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Health Risk Assessment of the B.K.K. Landfill, West Covina, California Prepared by: David M. Siegel, Ph.D., D.A.B.T. Lillian J. Kelly, R.E.H.S., R.N., M.P.H. Katherine L. Goldsmith, Dr.P.H, Hazardous Waste Toxicology Section Environmental Epidemiology and Toxicology Branch Health Hazard Assessment Division California Department of Health Services 714 P Street, Room 499, Sacramento, CA 95814 November 1990 INTERIM REPORT 28819 VSfW ACKNOWLEDGEMENTS In June 1990, a draft copy of the "Health Risk Assessment of the B.K.K. Landfill, West Covina, California" was reviewed by members of the Air Quality Advisory Committee, a technical subcommittee of the Interagency Steering Committee of the B.K.K. Landfill. The Department of Health Services expresses appreciation to the committee members for their critique of the draft report. Comments and suggestions were incorporated into this interim report. Statistical evaluation of the data in the 1984 Extended Monitoring Program of the risk characterization was performed by Joel Swartz, Ph.D., Environmental Epidemiology and Toxicology Branch. Special recognition is given to Sharon Davis, Office Technician, and Shirley Williams, Word Processing Technician, for their patient and diligent word processing support. R&S151883 TABLE OF CONTENTS LIST OF FIGURES...................................................................................................................................iii LIST OF TABLES................................................................................................................... iv GLOSSARY OF TERMS................................................................................................................................ vi EXECUTIVE SUMMARY...................................................................................................................................X INTRODUCTION......................................................................................... 7 Nature of Health Risk Assessments..................................................................................... 7 Purpose and Scope of this Health Risk Assessment................................. ,............. 7 History of the BKK Landfill, West Covina, California.........................................8 HAZARD IDENTIFICATION....................................................................................................................... 18 Indicator Chemicals Detected at the BKK landfill................................................18 Carcinogens Detected at the BKK Landfill.................................................................. 22 EXPOSURE ASSESSMENT............................................................................................................................ 25 Population in The Vicinity of the BKK Landfill.....................................................26 Pathways of Exposure to Neighboring Residents.......................................................32 Air Monitoring/Modeling Programs Used in the Quantitative.......................... 40 Risk Characterization DOSE-RESPONSE ASSESSMENT................................................................................................................ 43 Chronic Reference Doses......................................................................................................... 43 Inhalation Unit Risk Values................................................................................................ 45 RISK CHARACTERIZATION....................................................................................................................... 48 Risk Characterization of Exposure to Contaminants Detected........................ 48 in Offsite Surface Water Near the BKK Landfill Risk Characterization of Noncarcinogens Detected in .......................................50 Air Near the BKK Landfill Risk Characterization of Carcinogens............................................................................51 Numerical Estimations of Risk............................................................................................ 53 Limitations and Uncertainties............................................................................................81 Significance of the Risk....................................................................................................... 83 REFERENCES.............................................................................................. 85 APPENDICES Appendix A Summary of the Three Previous Health Risk Assessments of the BKK Landfill, West Covina, California. R&S151884 -i- Appendix B "Ambient Air Monitoring and Health Risk Assessment for Suspect Human Carcinogens Around the BKK Landfill in West Covina," March 1983. California Department of Health Services-Toxic Substances Control Division, California Air Resources Board, and South Coast Air Quality Management District. Appendix C "Estimates of Carcinogenic Risk in the Vicinity of the BKK Landfill," March 1986. K.S. Crump and Co., Inc., Ruston, LA. Appendix D "Risk Assessment for Exposure to Ambient Air in BKK Landfill in West Covina, 1978-1985," April 1986. Martyn T. Smith, Health Risk Associates, Berkeley, GA. the Vicinity of the Kenneth T. Bogen and Appendix E Analysis of Variance of the Data in EPA and DHS' 1984 Extended Monitoring Program. Note: Copies of the three previous health risk assessments of the B.K.K. Landfill are provided for the reader who wishes to review the methods and assumptions of those reports. R&S151885 -ii- LIST OF FIGURES FIGURE PAGE 1 LOCATION MAP, BKK LANDFILL, WEST COVINA, CA..................................... (Environmental Solutions, Inc.) 9 2 WASTE LOCATION INDEX MAP, BKK LANDFILL, WEST COVINA, CA..........................10. (Environmental Solutions, Inc.) 3 VICINITY MAP, BKK LANDFILL, WEST COVINA, CA.......................................................14 (Environmental Solutions, Inc.) 4 POPULATION CENSUS TRACTS IN THE VICINITY OF THE BKK LANDFILL............... 28 (CH2MHU1) 5 SENSITIVE POPULATIONS NEAR THE BKK LANDFILL (CH2MHU1).............................31 6 SCHEMATIC OF EXISTING AND POTENTIAL CONTAMINANT MIGRATION......................33 PATHWAYS, BKK LANDFILL (CH2MHU1) 7 AIR MONITORING PROGRAMS, BKK LANDFILL, WEST COVINA, CA (CH2MHU1) ..52 8 VINYL CHLORIDE IN AMBIENT AIR, 1983-1987 STATION A MONTHLY................. 57 MONITORING DATA, BKK LANDFILL, WEST COVINA, CA 9 AMBIENT AIR TOXIC MONITORING SITES IN THE SOUTH COAST AIR ....................69 BASIN (SCAQMD) NOTE: A parenthetical notation in the title credits the source of the Figure. A footnote on the Figure provides the full reference. R&S151886 -iii- LIST OF TABLES TABLE PAGE 1 HAZARDOUS WASTE TYPES DEPOSITED IN BKK LANDFILL, 1975-1984....................12 (Environmental Solutions, Inc.) 2 LISTINGS OF CHEMICALS DETECTED AND INDICATOR CHEMICALS............................. 19 BKK LANDFILL, WEST COVINA, CA (CH2MHI11) 3 CARCINOGENS DETECTED IN GROUNDWATER, SURFACE WATER, AND AIR................. 24 BKK LANDFILL, WEST COVINA, CA 4 SUMMARY OF POPULATION CENSUS TRACT DATA FOR THE VICINITY..........................29 OF THE BKK LANDFILL (CH2MHill) 5 POTENTIALLY SENSITIVE POPULATION SUBGROUPS FROM CENSUS TRACTS.............. 30 IN THE VICINITY OF THE BKK LANDFILL (CH2MHill) 6 INDICATOR CHEMICALS DETECTED IN OFFSITE SURFACE WATER................................. 35 1981-1985, BKK LANDFILL, WEST COVINA, CA 7 SUMMARY OF AIR QUALITY RELATED DATA COLLECTIONS FOR THE............................ 36 BKK LANDFILL AND VICINITY (CH2MHill) 8 AIR MONITORING/MODELING PROGRAMS USED IN THE QUANTITATIVE......................41 RISK CHARACTERIZATION OF THE BKK LANDFILL, WEST COVINA, CA 9 REFERENCE DOSES FOR INDICATOR CHEMICALS DETECTED IN....................................44 OFFSITE SURFACE WATER AND AIR, BKK LANDFILL, WEST COVINA, CA 10 INHALATION UNIT RISK (IUR) VALUES FOR CARCINOGENS DETECTED AT.............47 BKK LANDFILL, WEST COVINA, CA 11 COMPARISON OF INDICATOR CHEMICALS DETECTED IN OFFSITE............................... 49 SURFACE WATER, 1981-1985, TO ORAL CHRONIC REFERENCE DOSES, BKK LANDFILL, WEST COVINA, CA 12 VINYL CHLORIDE IN AMBIENT AIR (ppb), 1983-1987, MONTHLY AND ............... 56 ANNUAL GEOMETRIC MEANS, SCAQMD MONITORING STATIONS AROUND BKK LANDFILL, WEST COVINA, CA 13 INDIVIDUAL EXCESS LIFETIME CANCER RISK, SCAQMD AMBIENT VINYL............... 59 CHLORIDE MONITORING PROGRAM, BKK LANDFILL, WEST COVINA, CA 14 INDIVIDUAL EXCESS LIFETIME CANCER RISK, DHS-TSCP/CARB/SCAQMD............... 63 1982 EXPANDED MONITORING PROGRAM, BKK LANDFILL, WEST COVINA, CA 15 SUMMARY OF 1984 INDOOR MONITORING IN PRIORITY I HOMES............................... 65 AND A CONTROL HOME (CH2MHill) R&S151887 -iv- TABLE PAGE 16 INDIVIDUAL EXCESS LIFETIME CANCER RISK, EPA AND DHS 1984........................ 68 EXTENDED MONITORING PROGRAM, BKK LANDFILL, WEST COVINA, CA 17 1985 ANNUAL AVERAGE AMBIENT AIR CONCENTRATIONS OF VARIOUS...................... 71 TOXIC ORGANIC GASES IN THE SOUTH COAST AIR BASIN (SCAQMD) 18 INDIVIDUAL EXCESS LIFETIME CANCER RISK, CARCINOGENS.................................... 74 DETECTED AT EL MONTE STATION, 1985 LOS ANGELES BASIN AIR TOXICS MONITORING PROGRAM, AND ALSO DETECTED NEAR BKK LANDFILL, WEST COVINA, CA 19. SUMMARY STATISTICS FOR THE JANUARY 1987 THROUGH DECEMBER1987.................77 MONITORING DATA FOR VINYL CHLORIDE NEAR BKK LANDFILL (CARB) 20 RANGE OF CUMULATIVE POPULATION EXPOSED TO VINYL CHLORIDE........................ 78 NEAR BKK (CARB) 21 INDIVIDUAL EXCESS LIFETIME CANCER RISK, CARB MODELING OF........................ 79 1987 AMBIENT VINYL CHLORIDE CONCENTRATIONS NEAR BKK LANDFILL, WEST COVINA, CA 22 SUMMARY OF THE THREE PREVIOUS HEALTH RISK ASSESSMENTS OF THE BKK LANDFILL, WEST COVINA, CA...................................................................... Appendix NOTE: A parenthetical notation in the title credits the source of the Table. A footnote on the Table provides the full reference. R &S151888 -v- GLOSSARY OF TERMS ANALYSIS OF VARIANCE - A statistical technique that isolates and assesses the contribution of one or more factors to the variation in an outcome of interest. In analysis of variance (ANOVA), independent categorical variables (factors) are investigated for their influence on the dependent continuous random variable (outcome). Assumptions underlying ANOVA are: independence of the values, normality of the errors in the values, and equal variance for all observations. AMBIENT AIR - Outdoor air. AMBIENT AIR QUALITY STANDARD - A standard adopted by CARB in consideration of public health, safety, and welfare, including, but not limited to, health, illness, irritation to the senses, aesthetic value, interference with visibility, and effects on the economy; standards may vary from one air basin to another; standards relating to health effects are based on the recommendations of DHS (California Health and Safety Code Section 39606). An ambient air quality standard applies at the boundary of a facility. In 1978, CARB adopted an ambient air quality standard for vinyl chloride of 10 parts per billion (ppb) for a 24-hour average. The standard represented the limit of detection for vinyl chloride at that time. CARB - California Air Resources Board CAPCOA - California Air Pollution Control Officers Association CERCLA - In 1980, Congress passed the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) which established broad federal authority to deal with releases or threats of releases of hazardous substances. CERCLA, also known as Federal Superfund, was amended in 1986. CH2MHILL - A consulting engineering firm contracted by EPA in October 1985 to conduct an exposure assessment of the B.K.K. Landfill. CHRONIC REFERENCE DOSE - An estimate of the daily exposure to humans, including sensitive populations, that is likely to be without an appreciable risk of adverse health effects during the lifetime (70-years). Developed by EPA, the chronic reference dose is specifically designed to be protective for long-term exposures; the subchronic reference dose is used with short-term exposures. CLASS I LANDFILL - A classification system for landfills in California developed by state agencies. All landfills require a permit to operate. Class I landfills may accept hazardous waste, subject to federal and state regulations for hazardous waste management units. CLASS III. LANDFILL - A landfill that accepts only non-hazardous waste (municipal refuse and dewatered sludge). Class III landfills are regulated by state and local agencies. DHS - California Department of Health Services -vi- R&S151889 DHS-EETB * California Department of Health Services, Environmental Epidemiology and Toxicology Branch DHS-TSCP - California Department of Health Services, Toxic Substances Control Program EPA - United States Environmental Protection Agency HEALTH RISK ASSESSMENT - An analysis of the potential adverse health effects associated with exposure to hazardous substances based upon four systematic components: hazard identification, exposure assessment, dose-response ass ssment, and risk characterization. INDIVIDUAL EXCESS LIFETIME CANCER RISK - An upper-bound estimate of the probability of an individual developing cancer due to a lifetime (70-year) exposure to the level in question of a carcinogen. LANDFILL GAS - Methane, carbon dioxide, and trace gases generated by the anaerobic decomposition of buried organic wastes (both municipal and hazardous wastes). These gases serve as a transport medium for volatile organic compounds deposited or generated onsite. Landfill gas that is not collected by a gas collection system is released to ambient air, or migrates laterally through the soil before being released to the air or groundwater. LEACHATE - Any liquid, including suspended components in the liquid, that percolates through or drains from buried wastes. LINEARIZED MULTISTAGE MODEL - A mathematical model used to estimate the probability of incidence of disease by extrapolating from high dose animal studies to low level human exposures. This model is commonly used In quantitative carcinogenic risk assessments where the chemical agent is assumed to be a complete carcinogen and the risk is assumed to be proportional to the dose in the low region. This model yields estimates of risk that are conservative, representing a plausible upper limit for the risk. MAXIMUM CONTAMINANT LEVEL - The enforceable drinking water standard, based on health and technical feasibility. MAXIMUM LIKELIHOOD ESTIMATE - The best fit dose-response line from a set of data. POPULATION EXCESS CANCER BURDEN - An upper-bound estimate of the increase in cancer cases in a population as a result of a defined exposure to a carcinogen. RCRA - In 1976, Congress passed the Resource Conservation and Recovery Act (RCRA) which controls the generation, treatment, storage, and disposal of solid and hazardous waste. The Act, referred to as "cradle-to-grave" regulation of solid and hazardous waste, was amended in 1980 and 1984. R&S151890 -vii- RCRA PART B PERMIT APPLICATION Requires owners and operators of hazardous waste facilities to submit detailed information about a facility, such as: a description of the procedures, structures or equipment used to prevent runoff and contamination of water supplies; a topographic map showing surface waters, surrounding land uses (residential, commercial, agricultural, recreational); a wind rose; and injection and withdrawal wells onsite and offsite. Contents f Part A and Part B of the Application are specified in the California Code of Regulations, Title 22, Division 4, Chapter 30, Sections 66390 and 66391. SAM WORK PLAN The Site Assessment and Mitigation (SAM) Work Plan for the Class I Hazardous Waste Management Unit, developed by consultants to the B.K.K. Landfill in coordination with regulatory agencies. Provisions of the SAM Work Plan address ongoing monitoring requirements of the B.K.K. Landfill. SCAQMD - South Coast Air Quality Management District SLOPE FACTOR An upper-bound estimate of the probability of developing cancer per unit intake of a chemical over a lifetime (70-year). The slope factor is usually, but not always, the upper 95th percent confidence limit of the slope of the dose-response curve and is expressed as (mg/kg-day)"1. THRESHOLD - A dose level below which a response attributable to a particular substance will not occur. TOXIC AIR CONTAMINANT - An air pollutant which may cause or contribute to an increase in mortality or an increase in serious illness, or which may pose a present or potential hazard to human health. As established by legislation in 1983, and in consultation with DHS, CARB is implementing a program which first identifies and then controls toxic air contaminants (California Health and Safety Code Section 39650 ec seq, Food and Agriculture Code Section 14021 eC seq). UNIT RISK A measure of the carcinogenic potential of a substance, expressed in terms of risk per unit concentration of the substance in the medium where human contact occurs. The inhalation unit risk is an estimate of the probability of developing cancer as a result of constant exposure over 70 years to 1 ng/m3 of a substance in air. UPPER 95 PERCENT CONFIDENCE LIMIT - The statistical upper bound of the excess cancer risk derived from low dose extrapolation models. VOC - Volatile organic compound R&S151891 EXECUTIVE SUMMARY In October 1985, the United States Environmental Protection Agency (EPA) contracted CH2MHill to conduct an exposure assessment of the B.K.K. Landfill, W st Covina, California with the understanding that the California Department of Health Services (DHS) would perform a quantitative health risk assessment based on the data collected and evaluated. In August 1988, CH2MH111 completed its seven-volume report, entitled "B.K.K. landfill Environmental Exposure Characterization Report, West Covina, California." The report was reviewed by EPA, DHS, a technical peer review subcommittee, and a citizens advisory committee. This health risk assessment of the B.K.K. Landfill was prepared by the Hazardous Waste Toxicology Section of the California Department of Health Services, Health Hazard Assessment Division. The health risk assessment is concerned primarily with the risk of developing cancer from a 70-year exposure to the concentrations of carcinogens detected in air around the B.K.K. Landfill between 1982 through 1987. Air monitoring data from this period met retrospective quality assurance review for use in a quantitative risk characterization. The health risk assessment is divided into five parts: INTRODUCTION, which Introduces the health risk assessment and summarizes the history of the B.K.K. Landfill; R&S151892 HAZARD IDENTIFICATION, which gives information about the indicat r chemicals (carcinogens and noncarcinogens) detected in groundwater, surface water, and air in and around the B.K.K. Landfill; EXPOSURE ASSESSMENT, which describes the population in the vicinity of the B.K.K. Landfill, evaluates the pathways of exposure t neighboring residents, and describes the air monitoring programs used in the risk characterization; DOSE-RESPONSE ASSESSMENT, which identifies the chronic reference doses for noncarcinogens and the inhalation unit risk values for carcinogens used in the risk characterization; - RISK CHARACTERIZATION, which estimates the individual excess lifetime cancer risk and the population excess cancer burden from a 70-year exposure to the concentrations of carcinogens detected in air around the B.K.K. Landfill between 1982 through 1987. A summary of the three previous health risk assessments of the B.K.K. Landfill is provided in the Appendix for informational purposes. The B.K.K. Landfill in West Covina, California, operated a Class I landfill (that is, a landfill permitted for disposal of hazardous waste) from approximately 1972 to December 1984. During that time, the B.K.K. Landfill was the largest Class I hazardous waste land disposal facility in California and the primary hazardous waste disposal facility for the Los Angeles area. The Class I landfill began as 40 acres in 1972, expanded to 140 acres in 1975, -2- R&S151893 and by 1984 encompassed approximately 170 acres of the 583-acre facility. Acreage in excess of the 140 acres includes a buffer zone of the adjoining non-hazardous waste disposal area. Approximately 3.4 million tons of hazardous waste were deposited at the facility. Seventy-two percent of the waste was liquid hazardous waste such as acid solutions, alkaline solutions, solvents, and wastes containing vinyl chloride. Hazardous wastes were buried in drums, injected into wells, co-mingled with non-hazardous waste, r solidified (mixed) with onsite soil. The surrounding land was relatively undeveloped when the B.K.K. Landfill opened as a municipal waste disposal facility in 1963. Since that time, residential neighborhoods were developed to the north, west, south, and southeast. By 1985, EPA estimated the population within a one-mile radius from the center of the landfill to be approximately 40,000 persons (EPA, 1985). Beginning in 1969, neighboring residents complained about odors, surface water runoffs, spills, and dust releases from the facility. Since 1979, studies, investigations, and hearings have been conducted in response to complaints from residents and concerns of regulatory agencies. Environmental monitoring at the B.K.K. Landfill detected volatile . organic compounds in air, groundwater, and surface water in and around the facility. Vinyl chloride, a human carcinogen, was detected in ambient air at concentrations above California's ambient air quality standard of 10 parts per billion (ppb). EPA issued orders in 1984 and 1986 to the B.K.K. Corporation citing hazardous waste violations. On November 30, 1984, the B.K.K. Landfill stopped accepting hazardous waste. Under the direction of EPA and State -3- agencies, the fi.K.K. Landfill completed closure of the Class I landfill in March 1989, and is conducting a Site Assessment and Mitigation (SAM) Work Plan. A Class III (non-hazardous waste) land disposal facility continues to operate on approximately 150 acres of the remaining 413 acres. EPA contracted the engineering firm of CH2MH111 to conduct an exposure assessment to evaluate whether contaminants released from the B.K.K. Landfill presented a health risk to neighboring residents in comparison to background exposure concentrations. CH2MHill's report evaluated groundwater, surface water, and air monitoring data for 1975 to March 1986. The CH2MH111 rep rt had several Important conclusions about plausible past routes of exposure: 1) although groundwater below the B.K.K. Landfill is contaminated, groundwater is not used for drinking water or irrigation; 2) human exposure could have potentially occurred through ingestion or dermal contact with contaminated surface water released from the B.K.K. Landfill, but exposure would have been limited and infrequent; and 3) air monitoring data indicated an exposure pathway for neighboring residents. The hazard identification section and the exposure assessment section of this health risk assessment summarize information presented and evaluated by CH2MH111 in its 1988 report. The dose-response section identifies the toxicity values (reference doses and unit risk values current through June 1989) used in the quantitative risk characterization. The risk characterization section estimates the risk of adverse health effects associated with exposure to the concentrations of contaminants (carcinogens R&S151895 -4- and noncarcinogens) detected in offsite surface water and air for residents living near the B.K.K. Landfill. Because it is assumed that no threshold exists for substances that induce cancer, the risk characterization is concerned primarily with the risk of developing cancer from a 70-year exposure to the concentrations of carcinogens detected in air around the B.K.K. Landfill between 1982 through 1987. Individual excess lifetime (70-year) cancer risks are estimated using data from three site-specific air monitoring programs and one Los Angeles basin air monitoring program evaluated by CH2MH111, and one air modeling program of site data used by the California Air Resources Board (CARB). The population excess cancer burden is estimated for residents within a one-mile radius of the landfill. Ambient vinyl chloride monitoring data represent the most appropriate data to assess the excess cancer risk associated with the B.K.K. Landfill because vinyl chloride is a human carcinogen and is not commonly detected in the Los Angeles air basin. Carcinogens such as benzene, perchloroethylene, and trichloroethylene are detected in ambient air both at the B.K.K. Landfill and in the Los Angeles basin (SCAQMD, 1987). These compounds may present an additional cancer risk to people living around the B.K.K. Landfill, but it is not possible with the present data to distinguish between exposure due to ambient levels and exposure due to the B.K.K. Landfill. Vinyl chloride is rarely detected in ambient air and therefore more clearly represents exposure associated with the B.K.K. Landfill. -5- Based on the 1987 ambient vinyl chloride concentrations and the methods and assumptions used in this health risk assessment, the individual excess lifetime cancer risk associated with exposure to the carcinogen detected in air around the B.K.K. Landfill is estimated to be approximately 1 to 2 individuals in 100,000 persons. This assumes everyone is exposed to vinyl chloride at the 1987 concentrations for an entire 70-year lifetime. In the population of A0,000 persons living within a one-mile radius of the B.K.K. Landfill, less than one additional case of cancer would be expected to occur from this exposure. Currently, DHS and CARB are reevaluating the data on the carcinogenicity of vinyl chloride, in recent and past literature, for the purpose of identifying vinyl chloride as a toxic air contaminant. When this process is completed, a new unit risk value for vinyl chloride will be established. The new value is likely to be about 29 times greater than the value used in this health risk assessment. When this new value is adopted, DHS will prepare an addendum to this health risk assessment, reflecting the changed unit risk value for vinyl chloride, updating toxicity values, and adding air monitoring data collected since 1987. -6- R&S 151897 INTRODUCTION Nature of Health Risk Assessments Health risk assessments estimate potential adverse health effects associated with exposure to toxic and hazardous compounds based upon four systematic components: hazard identification, exposure assessment, dose-response assessment, and risk characterization. Each component refines the analysis and all four together are the assessment. Results of a health risk assessment are conditional on the methods and assumptions used, and the limitations and uncertainties identified. Health risk assessments are derived from the knowledge and technology available at a particular time, and consequently need to be continually reviewed to ensure consistency with scientific advances. Purpose and Scope of this Health Risk Assessment The purpose of this health risk assessment is to estimate, for residents living near the B.K.K. Landfill, the risk associated with exposure to the concentrations of contaminants detected in environmental monitoring of the facility through 1987. This 1990 health risk assessment updates a 1982 joint agency assessment (DHS-TSCP/CARB/SCAQMD, 1983) and is expected to be updated when reevaluation of the cancer potency of vinyl chloride is completed. Information on the history of the B.K.K. Landfill, the choice of indicator chemicals, and the exposure assessment was taken primarily from Volume I of CH2MH111' s seven-volume report to EPA. For a more detailed discussion of the -7- R&S151898 history, indicator chemicals, or exposure assessment, the reader is referred to that report (CH2MH111, Volume I, 1988). The CH2MH111 report was reviewed by EPA, DHS, a technical peer review subcommittee, and a citizens advisory subcommittee. Figures and tables taken from CH2MHH1' s report and other reports are individually referenced. History of the B.K.K. Landfill. Vest Covina. California The B.K.K. Landfill, operated by B.K.K. (Kenneth B. Kazarian) Corporation, is located within the corporate boundary of the City of West Covina, California, 18 miles east of downtown Los Angeles in Los Angeles County (Figure 1). In 1963, the B.K.K. Landfill opened on 130 acres in the San Jose Hills as a municipal waste landfill for the disposal of household and commercial refuse and inert solids such as construction debris. A land use permit was obtained from the City of West Covina, and waste discharge requirements were prescribed by the Los Angeles Regional Water Quality Control Board. In 1971, the City of West Covina approved an expansion of the facility from 130 acres to the present 583 acres, and permitted the disposal of hazardous waste onsite. In 1972, the B.K.K. Landfill opened a 40-acre Hazardous Waste Management Unit (that is, a Class I landfill) and began accepting hazardous waste. In 1975, the Class I Hazardous Waste Management Unit expanded by an additional 100 acres (Figure 2) , -8- R&S151899 Th B.K.K. Landfill was the largest Class I hazardous waste land disposal facility in California and the primary commercial hazardous waste disposal facility for the Los Angeles area. Annual summaries of hazardous wastes deposited at the facility are available for the years 1975 through 1?84. These summaries record that approximately 3.4 million tons of hazardous waste were deposited at the B.K.K. Landfill. Seventy-two percent of the waste was liquid hazardous waste. Wastes accepted in the greatest quantities were: acid solutions, alkaline solutions, contaminated soils, drilling muds, oil and oil sludges, tank bottom sediments, and other (unspecified) hazardous wcste (Table 1). Hazardous wastes were deposited onsite by four methods: buried in drums, injected into wells, co-mingled with solid non-hazardous waste, and "solidified" (mixed) with onsite soil. In 1963, the B.K.K. Landfill was located in a relatively undeveloped area of the San Gabriel Valley. In 1971, a residential neighborhood was sited approximately 2,000 feet from the northern border. By 1975, residential zoning and land use permits in West Covina allowed the construction of hemes up to the property line on the southern and southeastern borders (Figure 3). Migration of hazardous waste constituents from the landfill occurred. Anaerobic decomposition of the waste generated landfill gas which served as a transport medium for volatile organic compounds (VOCs) deposited onsite to migrate to ambient air. Hydrogeologic investigations found contamination in groundwater under the facility. -11- TABLE 1 (Environmental Solutions, Inc. ) TABLE 1.4 HAZARDOUS WASTE TYPES DEPOSITED IN BKK LANDFILL!')P) (1975-1984) ' (TONS) WASTE TYPE 1975 1976 1977 1971 1979 1980 1981 1982 1983 1984 TOTAL Acid Sludge Acid Solution Acid Solution w/Melab Acid Solution w/o Metals Acid Solution - Neutralized Adhesive Alkaline Sludge * Alkaline Solution Alkaline Solution w/Metals Alkaline Solution w/o Metab Alkaline Solution - Neutralized Alkali Solids Alum Sludge A. P. 1. Generator Sludge Aqueous Solution w/Mctab Aqueous Solution w/>10% Organics Asbejlos-Containing Waste* Ashes Baghouse Waste Bilge WateT Bio. Waste Other Than Sewage Blasting Sand Brine Cannery Waste Catalyst Chemical Toilet Waste Chemicab. Unused Containers, Empty Contaminated Equipment Contaminated Soil and Sand Cyanide Wasle Degreasing Sludge Detergent and Soap Distillation Bottoms Drilling Mud PCC Waste Filler Cake Fillets, spent Dux Fly Ash Gasoline and Wtfer Glaze Sludge Glue Hair Pulp Ileavy Metal Solution t kavy Meta] Sludge Ink and Solvent 19,300 49,59* 6*5 9,046 220 70* I7.2RR 33,497 62,761 172 22,991 45 2*9 12.316 41,756 70,747 329 17,310 34 385 13,773 71,615 69,712 t,)2l 3,*95 34 1,421 41,650 13,440 112,755 69,396 79,487 641 1,641 31 673 367 213 3,978 4,488 27,319 19,153 299 66,526 5,395 210 1,361 45,899 281 269 919 721 3,393 69 91 183 4,256 2,645 564 25,388 59 206 2,084 11 55 2,263 240 716 t.817 31,483 21,061 371 3,064 40,732 1,025 3,713 21,254 1,783 ISO 2,511 1,071 3,881 22,649 13,942 2,984 481 18,219 18021 12,595 6,312 30,292 4,729 2,506 1,692 2,868 404 8,974 11 485 1,073 6,523 79,927 1,257 1,332 1,235 7,394 4,323 2,238 304 14 30 1,590 542 6) 131 7,221 6.342 971 5,870 834 966 299,417 1,285 2,065 2,243 10,210 8,411 312 24 146 406 6,177 9,149 3,176 7,090 19,863 6,664 2,659 2*6 1,*90 271 3,623 *94 1,111 76,929 1,157 1,733 237 1,392 3,671 2,116 483,333 13,966 3,130 26,458 1,475 4,425 512,798 27,170 15,771 211 1,023 17,3*4 22,173 50,155 11,393 6,94* 2,12* 7,269 1,794 6*2 3,1*1 3,621 55,327 23,860 657 2.304 3,150 6,523 451,540 15,400 2.442 7,773 4,279 175,8*3 18,471 2,444 304 14 30 3,674 553 118 131 9,484 6,512 1,687 (1)Sourct: BKK annual waste summaries, 1975 through 19M, (2)Blanks in the table result from change in waste classifieation. to O Deposited in the greatest quantity during this period Reference: Modified from Cl LM Dill (March 6. 1986). H i-oei.sts'sy ENVIRONMENTAL TABLE 1.4 HAZARDOUS WASTE TYPES DEPOSITED IN BKK LANDFILL 0K2) (1975-1984) (Continued) (TONS) WASTE TYPE 1975 1976 1977 I97S 1979 1980 1981 1982 1983 1984 TOTAL Ink Sludge 76 541 617 Ink Wastewater 423 1,215 1,618 Laboratory Chemical) 186 253 439 Latex Waste 7M 3,107 446 6,482 5,433 1,586 658 606 19,032 Lime Sludge 3,055 10,304 10,679 2,737 26,775 Machine loot Coolant Meul Sludge Metal Dust and Machining Waste 3,528 1,376 3582 529 22,857 406 15,393 293 7,110 38,250 2,604 Mud and Water 17.754 51,486 29,259 65,816 44,457 31,426 1,177 248,375 Oil 24,610 11,229 9,467 27,405 22,276 14,137 1,204 471 3,650 1,369 115,838 CHI Sludge 2,568 9.516 70,711 26,345 109,140 Oil and Water Oil Containing Waste, Unspecified 35,201 33,631 24,703 18,462 70,832 43,165 Organic liquids 1,690 103 1,993 Organic Monomer Waste 131 281 412 Organic Solids 534 927 1,461 Paint Waste 9 : Paper Sludge/Pulp Pesticides 3,377 904 5.401 534 6,372 130 7,414 189 6,952 290 5,092 358 3,628 353 17,604 231 15,256 53 243 11,643 59 169 82,739 112 3,410 Pesticide Containers 24 79 42 145 Pesticide RJnsewater Pharmaceuticals 263 26 301 124 35 571 S3 61 714 727 Phenolic Waste 82 32 114 Phosphate Sludge 528 177 1,405 Photoprocessing Waste 123 1,445 1,099 1,680 5,047 Plating Sludge 1,870 5,949 7,819 Plating Solution, Acid 5,848 3,583 9.431 Plating Solution, Alkaline 879 2,480 3,359 Polychlorinated Biphenyls 7 49 65 121 Resin Waste Scrubber Waste 1,158 11,320 550 1,103 3,377 912 1,142 79 16.997 2,714 Solvent, llalogenated 1,046 9,491 1,392 515 12,521 Solvent, Hydrocarbon 813 153 652 122 2,440 Solvent, Oxygenated 181 171 1,211 224 1,864 Solvent, Mixed 19,418 14,662 17,612 960 52,652 Solvent, Unspecified 3,447 6,424 9,211 16,649 17,139 27,340 10,210 Spill Cleanup Stretford Solution 856 1,583 3,925 4,640 4,781 6,223 Sulfide Sludge Sump Sediment 211 625 12.734 25,920 2589 3,054 6,479 38,654 Tank Bottom Sediment Tanning Sludge Tetraethyl Lead Sludge Wastewater Treatment Sludge 24,205 88 52,742 91 57,661 100,434 124,448 146,152 35 25 60 3,250 15,863 24 290 13,088 855 6,344 39,964 1,097 32 16,674 44,471 150 5,170 11.733 1 2,221 614,898 1,252 513 49,809 Other Liquids Misc. Sludge Waste Other Hazardous Waste___________ 6,769 5,805 2,302 1,501 4,890 8.966 989 3,143 26,241 13,191 12522 1,970 20.037 74,451 43,571 14,492 124.721 TOTALS 178,733 268,897 259,487 418,683 428,261 459.507 287,813 493539 759,660 342,050 3,896,630 ENVIRONMENTAL (l)Soutce: BKK annual waste summaries, 1975 through 1984. <2)Blanks in the table result from change in waste classification. Deposited in the greatest quantity during this period. Reference: Modified from Cl IjM Hill (March 6, 1986). _-> ; ~r--------- 'yzZLr.:;y=* v/-, -------- ~ --/? 1 ^ y,fi i ' uS:-. \'rr n ^> A.-\ ; r^M'^rO' J^l: :k\. V *"ro -. R&S151903 1~^:^--^J|-f -, + S; ' . -X. ~*c,,,c, 7i Mn USGS Tfloognonc man / Booim Park Outtarangi* --I-- (Ottttd IBM, Pnp f#vMC.108i) * Sea* 124.000 FIGURE 1.2 VICINITY MAP BKK LANDFILL FACILITY ENVIRONMENTAL SOLUTIONS, INC. Source: Environmental Solutions. Inc., Figure 1.2, "BKK Landfill Site Assessment and Mitigation Work Plan, Book I, Subsurface: Site Characterisation," March 15. 1988. P* 1"3. -14- The first odor complaint against the B.K.K. Landfill was reported to the South Coast Air Quality Management District (SCAQMD) in 1969. The number of odor complaints reported to SCAQMD increased to 278 in 1979, 537 in 1980 and 936 in 1981. Neighboring residents have been concerned for many years about odors and hazardous waste releases in surface water runoff, spills, and dust from the B.K.K. Landfill, and have voiced general health concerns about living near a hazardous waste facility. Since 1979 various studies, investigations, and hearings have been conducted in response to complaints from residents and concerns of regulatory agencies. In 1980, SCAQMD began monitoring ambient air in the vicinity of the B.K.K. Landfill for odorous organic compounds. In 1981 vinyl chloride, an odorless gas and a human carcinogen, was detected in concentrations above California's ambient air quality standard of 10 ppb. In June 1981, the California Department of Health Services-Toxic Substances Control Program (DHS-TSCP) banned further disposal of waste containing vinyl chloride from the B.K.K. Landfill, and SCAQMD established a program to monitor ambient air around the B.K.K. Landfill for vinyl chloride. I The following nine agencies formed an interagency task force in 1981 to coordinate activities associated with the B.K.K. Landfill: California Department of Health Services (the Toxic Substances Control Program and Public Health) Los Angeles Regional Water Quality Control Board United States Environmental Protection Agency -15- R&S151904 California Waste Management Board South Coast Air Quality Management District City of West Covina County of Los Angeles Department of Public Works County of Los Angeles Department of Health Services County of Los Angeles Sanitation Districts. In 1983, EPA requested a Resource Conservation and Recovery Act (RCRA) Part B Permit Application from the B.K.K. Landfill. During a facility inspection and permit application review later that year, EPA found several violations regarding groundwater monitoring, bulk liquid disposal, and ignitable/reactive waste disposal. In April 1984, EPA issued B.K.K. Corporation a RCRA Section 3013 Order of Consent, requiring a comprehensive investigation of onsite and offsite contamination. In July 1984, 19 homes along the southern perimeter vere evacuated as a result of lateral subsurface migration of landfill gas. EPA issued B.K.K. Corporation a Comprehensive Environmental Respoi.se, Compensation, and Liability Act (CERCLA) Section 106 Order, requiring mitigation of landfill gas emissions and leachate migration. EPA and DHS monitored indoor air in homes, and reoccupancy criteria were developed.by DHS Epidemiologic Studies and Surveillance Section (DHS, 1984). All evacuated homes were allowed to be reoccupied by December 1984. On November 30, 1984, the B.K.K. Landfill withdrew its RCRA permit application, stopped accepting hazardous waste, and began closure of the Hazardous Waste Management Unit. At that time, the size of the Class I unit was defined as 170 acres, which includes a buffer zone from the adjoining non-hazardous waste disposal area. -16- R&S151905 In 1986, EPA again issued orders to B.K.K. Corporation: a RCRA Section 7003 Order finding that an imminent and substantial endangerment to human health may have been present from handling and disposal practices at the B.K.K. Landfill; and a RCRA Section 3013 Order finding that a substantial hazard to human health or the environment may have been present from air and groundwater contamination and the proximity of drinking water sources in the area. The B.K.K. Corporation retained Environmental Solutions, Inc. to pr pare a SAM Work Plan in response to the EPA orders and in conjunction with federal, state, and local regulatory agencies. In March 1989, closure of the Class I Hazardous Waste Management Unit was completed with the placement of the final cover and collection systems as stipulated in federal and state regulations. As part of the post-closure permit, monitoring will continue at B.K.K. Landfill, and may continue for 30 years from the date of closure. A Class III (non-hazardous waste) land disposal facility continues in operation on approximately 150 acres of the remaining 413 acres. SAM Work Plan activities completed in 1989 included: a "phase I" site hydrogeologic characterization, a landfill gas analysis, flare source testing, a soil and sediments sampling program, an ambient air gas and particulat monitoring program, and an air tracer test. An odor study, an elevated subsurface temperature and carbon monoxide sampling program, and a surface emissions program were in progress. Final SAM Work Plan reports are due in December 1990. -17- HAZARD IDENTIFICATION The hazard identification component of a health risk assessment determines whether or not chemicals present at a site may pose a hazard to human health, and whether the health hazard is carcinogenic or noncarcinogenic. Noncarcinogenic effects may result from acute or chronic exposures, and threshold levels are established below which no adverse health effect is expected. It is assumed that no threshold exists for carcinogens. This section identifies the indicator chemicals (carcinogens and noncarcinogens) detected in groundwater, surface water, and air in and around th B.K.K. Landfill. Indicator Chemicals Detected at the B.K.K. Landfill CH2MHill prepared a list of all chemicals detected in groundwater, surface water, and air around the B.K.K. Landfill (CH2MH111, 1988). To focus on the contaminants' of primary concern, CH2MHill applied the indicator chemical selection process, outlined by EPA in the "Superfund Public Health Evaluation Manual (1986)", and identified carcinogen and noncarcinogen indicator chemicals (Table 2). The indicator chemical selection process directs attention to the contaminants of primary concern to human health and the environment, while not excluding any chemical that may cause harm to human health or the environment. Criteria used in the selection process are: the measured concentration of the -18- TABLE 2 (CH2HMIU) LISTING OF CHEMICALS DETECTED AND 1MDICATOS CHEMICALS FOB GROUNDWATER, SURFACE WATER, AND AIR* BKK LANDFILL, WEST COVINA, CALIFORNIA A: GROUNDUATER CHEMICALS DETECTED INDICATOR CHEMICALS VOLATILE ORGANICS 1,1,1Trichloroethane 1,1,Z,Z-Tetraehloroethane 1,1,Z*Trichloroethane 1,1 -0iehtoroethane 1,T-Dichloroethylene I,2-Diehlorobemene 1,2-Diehloroethane 1,2-Dichloropropane 1,3-Dichlorobenzene 1,4-Dichlorobenzene 2-Butanone Acetone Beniene Bromomethane Carbon tetrachloride Chlorobentene Chloroethane Chloroform cis*1,2-Dichloroethylene trens-1,2-Dichlorocthylene Ethylbenzene Methylene Chloride Xylenes o-Chlorotoluene Perchloroethylone Propylbentene Styrene Toluene Trichloroethylene Trichloromonofluoromethane Vinyl Chloride SEMI'VOLATILES 1,2,4-lriehlorobenzene 1,3,5Trimethylbentene 2 Maxanone 2,4-Dimethylphenol bis(2-Chloroethyl)ether bis(2'Chloroisopropyl>ether bis(2-EthylhexylIphthalate Dibutylphthalate Oiethylpnthalate Oimehtylnitrosamine di-Octylphthalste lsophorone Napthalene n-Nitrosodimethylamine Phenol Phenols (total) Tetrahydrofuran INORGANICS Arsenic Barium Boron Cadaiun Chromium total) Cobalt Copper Cyanide Fluoride Iron Lead Manganese Mereury Nickel Nitrates Seleniun Silver 2inc NON-CARCINOGENS VOLATILE ORGANICS 1,1,T-Trichloroethane 1,1 *Diehloroethane l,2'Dichlorooentene 2-Butanone Chlorobenzene cis-1,2-Dichioroethylene trons-1,2-Diehloroethylene Ethylbenzene o.p-Xylene Toluene SEMI-VOLATILES Phenols, (total) Phenol INORGANICS Barium Cadaiua Copper Fluoride Lead Manganese Mercury Silver Zinc CARCINOGENS VOLATILE ORGANICS 1,1,2,2-Tetraehloroethane 1,1,2-Trichloroethane 1,1-Dichloroethylene 1,2-Diehloroethane Benzene Carbontetrachloride Chloroform Methylene Chloride Perchloroethylene Trichloroethylene Vinyl Chloride SEMI-VOLATILES bis(2-Chloroethyl)ether n-Nitrosodimethylamine INORGANICS Arsenic R & S 151908 *Chemicals detected represent those found in the landfill gas; the indicator chemicals represent those analyzed in the aionitoring programs SYNONYMS 2-Butanone * Methylethylketone 2-Hexanone Methylbutylketone n-Nitrosodimethylamine * Dimethylnitsosannne Methylene Chloride * Dichloromethane Perchloroethy1ene * Tetrachlorocthylene TABLE 2 (Continued) LISTING OF CHEMICALS DETECTED AND INDICATOR CHEMICALS B; SURFACE WATER CHEMICALS DETECTED , INDICATOR CHEMICALS VOLATILE ORGANICS 1.2-Dichlorobenzene 1,1,1T richloroetnane 1.1.2-Tricnioroetnane 1,1 * D i eh l oroetnane 1.1-Diehloroethylene 1.2-Dichloroethane Acetone Benzene BremodiChloromethane Chlorobenzene Ch l orod i Bromoeietnane Chloroform cts-l,2-Dichloroetnytene trans-1,2*Diehloroetnylene Dichiorometnene Ethylbenzene Xylenes o-Cntorotoluene Perchloroethylene Styrene Propylbenzene Toluene Trichloroethylene Vinyl chloride SEMI'VOLATILES 1,3,5-Trimethyl benzene 1.A-Dtehlorooenzene Acenaphtnene bis(2-EthyUiexyl)bhthalate Dioutyt bhthatate oi-Octylohthalate nitrosoaionenylamine Phenols (total) INORGANICS Arsenic Codmiun Chromiun (total) Copper Cyanide Lead Nickel Seleniun Silver Zinc NON-CARCINOGENS VOLATILE ORGANICS 1,1,1-Trichloroethane 1,1Dichioroetnane 1,2-Dichlorooenzene Chlorooenzene Ethyl Benzene Xylenes Toluene SEMI-VOLATILES Phenol (total) INORGANICS Codeine Chromiun (total) Copper Cyanioe Lead Nickel Seleniun Zinc CARCINOGENS VOLATILE ORGANICS 1.1.2-Trichloroetnane 1.2-Diehloroethane Benzene Chloroform Methylene Chloride Perchloroethylene Trichloroethylene vinyl Chloriae INORGANICS Arsenic The indicator chemicals reoresent those anaIvied in the monitoring programs SYNONYMS 2-Butanone * Methylethylketone 2-Hexanone Methylbutyl ketone n-Nitrosodimethylomine * Dimetnylmtrosamine Methylene Chloride * Dichloroethane Perchloroethylene * letrachloroethvlene R&S151909 -20- TABLE 2 (Continued) LISTING OF CHEMICALS DETECTED AND INDICATOR CHEMICALS C: AIR* CHEMICALS DETECTED INDICATOR CHEMICALS VOLATILE ORGANICS 1.1-Diehloroethane 1.1 -Diehl oroethyl ene 1.2-Dichloroethane 1.3-Dichtoropropene 1.1.1 - T r i ch l oroethane 1,1,2-Trichloroethane 2.3-Dimethylbutane Benzene Carbon Tetrachloride Chlorobenzene Chioroethane Chloroform Cyclohexane eis-1,2-Dichloroethylene trans-1,2-Dichloroethylene Hexane isopropylbenzene lso-octane Methane MethyIcyclohexane Methycyelopentane Methylene Chloride Nonane n-Propylbenzene Perchloroethylene Toluene Trichloroethylene Vinyl Chloriae Xylene (total) NON'CARCINOGENS VOLATILE ORGANICS 1,1,1-Trichloroethane Chlorobenzene trans-1,2-Dichloroethylene CARCINOGENS VOLATILE ORGANICS 1,1 *Dichloroethylene 1,2-Dichloroethane Benzene Carbon Tetrachloride Chloroform Perchloroethylene Trichloroethylene Vinyl Chloride BASE/NEUTRALS 1,4 * Dichlorobenzene Dichlorobenzene ACID EXTRACTABLES 2-Butanol Chemicals detected represent those found in the landfill gas; the indicator chemicals represent those analyzed in the monitoring programs SYNONYMS 2*Butanone Methylethyl ketone 2-Hexanone * MethyIbutylketone n-Nitrosodimethylamine = Dimethylintrosamine Methylene Chloride = Dichloromethane Perchioroethyiene * Tetrachloroethylene R&S151910 Source: CH2MHi.il, Table 5-A, "EKK Landfill Environmental Exposure Characterization Report. West Covina, California," August IS. 1988, Voiisse 1, p. 5-22. -21- chemical; the toxicity of the chemical; and the physical/chemical properties of the chemical, which determine fate and transport in environmental media. Consequently, indicator chemicals represent the most toxic, mobile, and persistent chemicals at a site as well as those in the greatest concentrations. Carcinogens Detected at the B.K.K. Landfill EPA evaluates available data on the carcinogenic effects of chemicals from two sources: human epidemiologic investigations and long*term animal tests. EPA applies to the data a "weight of evidence" judgment on the likelihood that the chemical is a human carcinogen (EPA, 1986; EPA, 1989). The evidence is characterized separately for human studies and animal studies as sufficient, limited, inadequate, no data or no evidence. For example, the weight-of-evidence for human studies is as follows: sufficient evidence of carcinogenicity, which indicates that there is"a causal relationship between the chemical and human cancer; limited evidence of carcinogenicity, which indicates that a causal interpretation is credible, but that alternative explanations, such as chance, bias, or confounding, could not adequately be excluded; inadequate evidence. which indicates that either there were few pertinent data, or that available studies, while showing evidence of association, did not exclude chance, bias, or confounding and therefore a causal interpretation is not credible; -22- no data, which indicates that data are not available; no evidence, which indicates that no association between an exposure and an increased risk of cancer was found in well-designed and well-documented epidemiologic studies. Based on the "weight of evidence", EPA classifies carcinogens as follows: - Human carcinogen, i.e., sufficient evidence of carcinogenicity in humans; - SI: Probable human carcinogen, i.e., sufficient evidence of carcinogenicity in animals with limited evidence in humans; - S2: Probable human carcinogen, i.e., sufficient evidence of carcinogenicity in animals with inadequate evidence in humans; - : Possible human carcinogen, i.e., limited evidence of carcinogenicity in animals with inadequate evidence in humans; JJ: Not classifiable as to human carcinogenicity, i.e.. Inadequate evidence of carcinogenicity in animals with no evidence in humans; - : Evidence of noncarcinogenicity for humans. The "weight of evidence" classifications for the carcinogens detected in groundwater. surface water, and air around the B.K.K. Landfill are A, B2, and C. The sites of carcinogenic effects for these chemicals include the liver, lung, skin, kidney, breast, and stomach. Table 3 presents this information for the carcinogens detected around the B.K.K. Landfill, based on toxicological data current through June 1989. -23- R&S151912 TABLE 3 CARCINOGENS DETECTED IN GROUNDWATER. SURFACE WATER, AND AIR BKX LANDFILL WEST COVINA, CALIFORNIA Carcinogen CAS#* EFAb Class Cancer Site Arsenic (inorganic) Cadmium Chromium(VI) Lead Nickel Benzene Bis-2-ehloroethyl ether Carbon Tetrachloride Chloroform 1,2-Dichloroethane 1,1-Dlchloroethylene Methylene chloride N-nitrosodimethyLamina Ferchloroethylene 1,1,2, Z-Tetrachloroethane 1,1,2-Trichloroethane Trichloroethylane Vinyl chloride - A lung, skin - B1 lung, prostata, mammary - A lung " B2 kidney, lung, nervous system - A lung, nasal 71-43-2 A hematopoietic system (leukemia) 111-44-4 B2 liver 56-23-5 B2 liver 67-66-3 B2 kidney, liver 107-06-2 B2 sttssach, breast, uterus circulatory system, lung, liver 75-35-4 C kidney, breast, lung 75-09-26 B2 liver, breast lung, hematopoietic system (leukemia) 62-75-9 B2 liver, lung, kidney, circulatory system 127-18-4 C liver 79-34-5 C liver 79-00-5 C liver, kidney, adrenal, spelen, circulatory system 79-01-6 B2 lymph, liver 75-01-4 A liver a- Chemical abstract service number b- EFA weight of evidence classification: A, sufficient evidence in humans; Bl, sufficient evidence in animals, limitad in humans; B2. sufficient avidsnca in animals, inadequate in humane; C, limited evidence in animals, inadequate in humane. Taken from EFA'e Integrated Risk Information System (IRIS}, June 1989. With the exception of 1,1-diehloroethylene and certain lead compounds, the above carcinogens are listed as known to the State of California to cause cancer for purposes of the Health and Safety Code Section 25219,5 at aaq. R&S151913 -24 EXPOSURE ASSESSMENT The exposure assessment component of a health risk assessment identifies and describes the population at risk, and the types, frequency, magnitude, and duration of exposures. This section describes the population in the vicinity of the B.K.K. Landfill, evaluates the pathways of exposure to neighboring residents, and tabulates the air monitoring programs which will be used in the risk characterization. For a more detailed analysis of the exposure assessment, the reader is. referred to Volume I of CH2MHill's report (CH2MH111, 1988). In October 1985, EPA contracted CH2MH111 to conduct an exposure assessment as a technical enforcement support activity. The regulatory basis for the assessment was RCRA Section 3019, Subsection (b) and the procedural basis was the Superfund Public Health Evaluation Manual (EPA, 1986). The report, completed in 1988, included data available through March 1986 and consisted of the following volumes: Volume I - Text; Volume II * Plates; Appendices Volume 1 (groundwater data), Volume 2 (groundwater data), Volume 3 (groundwater data), Volume 4 (groundwater and surface water data), Volume 5 (surface water, air, and soils data). Limited environmental monitoring data for the B.K.K. Landfill and the surrounding area have been collected since 1975, specifically: groundwat r data are available from 1975 to the present; surface waters have been sampled since 1980; landfill gas, ambient air, and odor studies have been conducted -25- R&S151914 onsite and offsite since 1979. In 1984, ten onsite soil samples were analyzed for particle size only; one offsite residential soil sample was analyzed for volatile organic compounds and none were detected. CH2MHill's objectives for the exposure characterization were: 1. to compile and evaluate existing environmental monitoring data collected onsite and near the B.K.K. Landfill; 2. to provide detailed analyses of the data to assess whether exposure to contaminants released from the B.K.K. Landfill posed either an immediate or a long-term risk to human health or the environment, in comparison to background exposure concentrations. Data analyses included both: retrospective quality assurance review of the environmental monitoring data, and fate and transport evaluation of the contaminants in groundwater, surface water, and air. Population in the Vicinity of the B.K.K. Landfill In 1963, when the B.K.K. Corporation received its permit, the landfill was located in a relatively undeveloped area of the San Gabriel Valley. In 1967, the California Department of Finance estimated a population of approximately -26- R&S151915 67,000 in West Covina to the north and west of the facility, and a population of approximately 4,500 in Walnut to the east. In 1988, the Department of Finance estimated a population of 94,000 in West Covina and 25,000 in Walnut. CH2MH111 identified the age and sex distribution of the population in whole census tracts around the B.K.K. Landfill (Figure 4, Tables 4 and 5). Ethnicity, occupation, and socioeconomic status were not characterized. Demographics, prepared by CH2MH111 from the 1980 U. S. population census, indicated that the residential communities in and around the B.K.K. Landfill consisted primarily of young adults, families with children, and women of childbearing age. CH2MH111 examined sensitive population groups within a one-mile radius of the landfill boundary and identified 12 elementary schools, 2 child care centers, and 1 nursing home (Figure 5). The population within a one-mile radius around the landfill was estimated for use in previous risk assessments and in the exposure assessment. In 1982, three agencies jointly conducted the first health risk assessment (DHS-TSCP/CARB/SCAQMD, 1983) and identified a population of 7,700 people at a distance of one mile from the B.K.K. Landfill property line. This population was derived by dividing the assessor's plot maps into quadrants corresponding to four monitoring stations (A, B, D, and F), and estimating the population within each quadrant using 1980 census data. In 1985, EPA identified a population of 40,000 people within a one-mile radius from the center of the landfill (EPA 1985). The difference in population numbers reflect different estimation methods rather than real population increase. This 1990 health -27- S ource: CH2MH111. F ig u re 6 -3 , "BKK L a n d f ill E n v iro n m e n ta l Exposure C h a ra c te ris a tio n R e p o rt. West C ovina, C a lifo r n ia ," August 15, 1988, Volume I , p , 6-22. FIGURE 4 <CH2ttHill) ueistssa e o.t i.e cate: i i<*` > 1 *"it FIGURE g-3 FOPUtATIOM CENSUS TRACTS IN TWE VICINITY OF THE BKK LANDFILL tKK lANOHU tHYIAONMtNTAL tSOOSUef CH*RAC1CHIlMIOM Source: CB2HB111. Table 6 -4 , "BKK L a n d f i l l E n v iro n m e n ta l Exposure C h a ra c te riz a tio n R eport West Covina, C a lifo r n ia ," August IS , 1988, Volume I , p. 6-21. TABLE U (CH2MH111) ( Table 8-4 simhu) or ropuuTioH census tmct mm ros me vicihitt or me bkk uuvriu. fooulatloo Group Conttlns BAX South (680! TWITST- 468l.l1 I. Ml Groups Total Children (0-4) Children f)-9) Children (10-111 Children (IS-19) Adult* 110-10 Adults 115-44) Adults It)*) Nedlftn *9# s,jn 111 m 300 189 til i,eis 118 17.7* 10,515 1,114 1,057 756 til 1,01] 9,571 118 17.1 6,101 64 940 l,0il 1,057 666 ],m no 31.0 40(1.6] locillea 9e1sttee te till Landfill (Census Traci Wo. Beige) tsst-SoutbeMt Nost-toutbucst Northwest 4014 408(.01 nir 4DT9 40BD.D1 (944.01 46*6.dJ TBE! 7,101 715 811 897 810 ttl 3,m 771 17.1* 11,474 1,144 i.m 1,48) 1 ,)98 714 t,m 771 14.8 8,0)5 9)8 581 874 81) 907 1,948 1)1 18.1" 7,107 589 711 111 984 811 1,180 197 71. 1* 9,015 418 481 5)5 547 175 1,4)1 111 18.1* 1,885 )48 185 405 505 598 1,4)8 158 18.6* 1,759 155 191 191 571 119 1,551 101 II. 1* 1,998 174 780 )43 110 388 1,989 1)8 19.8* 5,414 181 187 380 509 801 1,1)1 )) 19.) North Northeast 1084.01 <041.01 "IMJ 4,1)4 177 111 II) S39 MO ),) 111 10.0 1,898 91 9) 178 1)5 108 , 1,081 111 11.8 3,836 no 181 301 50) SOI 1,911 11) II.1* It. resales Total Feoalea <0-1*1 resales (10-MI realist Ili-tO reoslet It)*) 1,191 811 1,00) 791 76 9,187 i.ati 1,151 1,141 no 4,097 1,917 89) i.m 171 ),419 1,999 9t0 91) 151 t,14f 1,584 1,891 1,818 199 1,997 1,178 887 880 94 1,978 1,547 95 1,018 108 1,5)7 1,01) 688 157 100 1,489 111 880 757 100 1,108 7)1 SOI 1,001 189 1,000 8(8 181 718 111 1,815 TM 18 95) 1)8 1,178 718 ISO 91 110 970 1,19) 117 $81 149 418 1)7 11$ 87 138 `Represents the aearegt aedlta age far tbe census tract, because aedlans are calcalsted separatelr for populations elthla eecti cltf bouodsrr elthin each census tract. Soiree! Based on 1880 Census (U.I. Dept, ol Coeoetce, 19811. USUFESI/036 816(9(5^ Sourca: CE2MHI1L. T a b la 6 -5 , "BKK L a n d f i l l E n v ic o o n a n ta l Expoaura C h a ra c ta rix a tio n R a p o rt Wast C ovina, C a lifo r n ia , " August. 15, 1988, Volusia 1, p . 6 -2 9 . TABLE 5 (CH2HH111) Table 6-5 potentim.lv sensitive population subgroups from census tracts 1 IH THE VICINITY OF THE BKK LANDFILL Regions (Located Relative to BKK) Contains BKK South East-Southeast Northeast North Northwest West Southwest Census Tract No. 4080.01 4081.31 4081.32 4081.02 4081.01 4034 406J 4064.01 4064.02 4065 4066.01 4066.02 4080.02 4079 4070 Percent of Census Tract Populations by Subgroups Females of Child- Senior Infants Children Bearing Age Adults (0-4 yrs) (5-14 yrs) (15-44 yrs) (65+ yrs) 10.6 12.7 28.4 2.8 11.9 10.4 10.0 17.2 24.7 23.8 29.5 24.0 24.7 2.2 3.8 3.8 8.9 20.6 23.9 9.3 22.0 27.8 2.8 2.2 2.9 12.8 24.8 6.4 6.3 16.4 23.3 4.8 14.2 20.6 6.0 6.5 6.7 13.7 25.5 5.4 14.4 23.6 8.1 15.6 22.3 7.1 6.4 6.4 7.9 15.7 29.2 9.7 20.0 25.7 3.2 3.6 8.3 22.3 25.4 2.8 Total No. of Females of ChildBearing Age (15-44 yrs) 1,511 3,109 1,943 1,781 1,443 3,465 950 1,031 391 1,391 1,124 891 1,418 1,287 . 1,804 Census Tract Total No. 5,324 10,535 8,101 7,201 6,025 12,478 3,826 4,424 1,898 5,444 4,759 3,998 4,855 5,015 7,107 Region Total No. 5,324 25,837 18,503 3,826 6,322 14,201 i 9,900 7.107 Source of Data! 1900 Census tU.S. Dept, of Commerce, 1983) LASUPER8/031 6I6l-SI.S'8U FIGURE 5 (CH2MH111) 026LSLSW S o u rc e CB2MH111, F ig u re 6 .4 , "BKX L a n d f ill E n v iro n m e n ta l Exposure C h a ra c te ris a tio n R e p o rt, Meet C ovina, C a lifo r n ia ," August IS , 1988, Voliane I , p. 6-27. risk assessment uses EPA's population estimate of AO,000 people within a one-mile radius of the landfill. Pathways of Exposure to Neighboring Residents Pathways of exposure to humans include environmental media (air, water, soil, and food) and routes of exposure (ingestion, dermal contact, and inhalation). CH2MH111 prepared a schematic (Figure 6) to illustrate existing and potential pathways of exposure to contaminants from the B.K.K. Landfill. All the pathways together represent the total exposure from the site. Analysis of each individual pathway represents the exposure to different populations, such as onsite workers or neighboring residents. Groundwater Although groundwater below the B.K.K. Landfill has been contaminated, contaminants from the landfill have not been detected in the municipal drinking water supply wells, located one to three miles from the facility. Mitigation measures and monitoring schedules stipulated in the SAM Work Plan are designed to detect if contaminants migrate to municipal drinl.ing water supply wells, at which time EPA and/or the State would issue a corrective action order. Groundwater in the vicinity is not used for irrigation. Seeps near the B.K.K. Landfill may have provided a potential source of exposure to contaminated groundwater in the past during rainy seasons. Seeps were dewatered by extraction wells, and have been dry since 1984. -32- 33 Co U) CroO FIGURE 6 (CH2HH111) ssetsi-s^u S ource: CH2MHU1, fig u r e 6 .1 , "BMC L a n d f i l l E n v iro n m e n ta l Exposure Characterization R e p o rt. West Covina, C a lifo r n ia ," August 15, 1988, VoLuae I . p , 6 -3 . Surface Water Three surface water drainage areas exist around the B.K.K. Landfill: Vine Creek Drainage to the north, Nogales Street St rm Drain/Giano Channel Drainage to the southeast, and Puente Creek Drainage to che southwest. Measured and estimated concentrations of contaminants in surface water originating from the landfill were less than the Clean Water Act criteria for acute toxicity in freshwater organisms; drainages are ephemeral and do not support permanent populations of aquatic organisms (CH2MHill, 1988). Human exposure could have potentially occurred through ingestion or dermal contact with contaminated surface water released from th B.K.K. Landfill. Unfortunately, no quantitative estimate of exposure can be made based on the available information. Median values of indicator chemicals detected in offsite surface water are given in Table 6. The volume of rui.off discharge from the Nogales Street Storm Drain/Giano Channel Drainage was reduced 95 percent in November 1986, at which time drains and containment measures were constructed on the landfill. Soil Soil from only one residential yard located on Miranda Street was analyzed in July, 1984 for VOC's and none were detected. Air Fifteen separate air sampling programs were conducted between 1979 to 1986. These programs included odor studies, landfill gas emissions monitoring, flare gas testing, periodic and continuous ambient air monitoring, and indoor air monitoring. CH2MHill tabulated the 15 programs, dates, and methods (Table 7) . Sampling stations located in residential neighborhcods -34- R&S151923 TABLE 6 INDICATOR CHEMICALS DETECTED IN OFFSITE SURFACE HATER, 1981-1985 BKK LANDFILL, WEST COVINA, CALIFORNIA Indicator Chemical Non-Carcinogens Trans-l,2-Dichloroetbylen 1.1.1-Trichloroathane 1.1-Dichloroethane 1.2-Dichlorobanrana Chlorobanzana Ethyl banzana Xylanaa Toluene Phanol Copper Cyanlda Selenium Zinc Median Value* (cnbl 2.4 3.4 56 NDb 1.08 ND 0.2 0.2 3,900 40 3 41 17,000 Location (tons drain, Azusa Avenue storm drain, Azusa Avenue runoff discharge, Nogales Street Galater Park Spring storm drain, Azusa Avenue Galater Park Spring storm drain, north of entrance gate storm drain, north of entrance gate Bidden Valley Spring south fork, Puente Creak GIB manhole, Amar and Hoodgate Galater Park spring Carmen's Fond discharge Carcinogens Arsenic Cadmium Chromium Laad Nickel 1.1.2-Trichloroethane 1.2-Dichloroethane 1,1-Dichloroethylene Benzene Chloroform Methylene Chloride Perchloroethylene Trlchloroethylene Vinyl Chloride BO** 2 5 12 100 14 230 3.2 ND* 1.7 71 3.3 2.1 40 runoff discharge, Nogales Street Bidden Valley Spring storm drain, Azusa Avenue storm drain. Nogslea and Shakespeare seep above Miranda Street runoff discharge, Nogales Street rtmaff discharge, Nogales Street seep above Miranda Street Galater Park Spring storm drain, north of entrants gate runoff discharge, Nogales Street runoff discharge, Nogales Street runoff discharge, Nogales Street seep above Miranda Street a: Median values taken from Table 3-18 BMC Landfill Comparison of Contaminants Detected In Offsite Surface Water With State And Federal Standards, "BKK Lsndfill Environmental Exposure Characterization Report West Covina, California," CB2MH111, 1988, Volime I, pgs. 3-90 to 3-94. b: Taken from Table 5-21 Maximum Values of Indicator Chemicals In Surfsce Wstsr Samples Collected From the Vincinity of the BKK Landfill, CH2MH111, 1988, Vobarn I, pgm. 5-125 to 5-127. ND - Not Dstsctad. R&S151924 -35- _____ Sampling Program_____ Investigation of Odorous and Volatile Coapounds for BKK Landfill Sampling Period Nov. 1979 June 1980 TABLE 7 (CH2HHill) Table 3-19 SUMMARY OF AIR QUALITY RELATED DATA COLLECTIONS FOR THE EXE LANDFILL AND VICINITY Sampled By Sampling Activities Univ. of So. Cal, Environ. Engineering Dept. Onsitei o Suction pump sampling using a Tenas-GC trap for Volatile Orgenlce o Suction pump sampling for K^S Page 1 of 4 Sample Analyses o GC/MS speciation of organics (limited) i U> BKK Odor Study CT\ Oec. 19B0 Euteck Inc. Onsitai o Landfill gas sampling o GC analysis of gas samples BKK Plare Station No. 1 Source Testing April, Kay, and June 19B0 SCAQKD Onsitet o 2 liter bulb sampling of gas collection system inlet end gee outlet (et the flare)t and ambient samples onsite and offalte o GC/HS analysis for Vinyl Chloride Ambient Air Monitoring Program June 19B1 present SCAQMD Offsitai o 24-hour Tedlar bag samplings et vsrlous locations around the site o Two long-term stations and 12 mid- or short-term stations used to evaluate etation altlngi o GC analysis for Vinyl Chloride only o 10 ppm detection limit for 6/BI through 12/82 o 2 ppm detection limit for 1/B3 through present S6iSIS?b Table 3-19 (Continued) Page 2 of 4 Sampling Program BKK Expanded Monitoring program Sampling Period July 19, Oct. )5, 1962 Sampled SCAQHD, ABB, and D0I1S-TSCD Sampling Actlvltlee Of falter o 24-hour Tedlar bag samplinga at S station* near the aite and one control site Sample Analyaea o GC/HS analysis for eight vola tile organic compounds Directional Ambient Air July-Aug. 1962 5CAQMD Sampling and Kicro- meteorological Survey i U-i-JJ BKK Flare Station Mo. 1 Oct. 1982 ARB Source Testing Onaltei o Mine directionally controlled portable bag sampler*, and eight portable wind recorders Onaltei o Grab samples in Tedlar bags from the Inlet line and from four burners o GC analysis for Vinyl Chloride only o GC/MS analysis for six volatile organic compounds o Four composite samples of ambient air (2-to 3-hour com posites) upwind and downwind of disposal areas BKK Flare Station Ho. 1 Source Testing Oct. 1983 Science Application* Inc. for BKK Onsite o Samples collected at the main header to the flare station (inlet)t sample collection method unknown (to be deter mined o GC/HS analysis, 23 volatile organic compounds detected ambient air Monitoring During Drilling at Barrier 2 May and June 1964 BKK Oneit ei o Eight-hour composite and grab samples In Tedlar bsgst from one upwind and two downwind stations to the drill site o GC analysis for Vinyl Chloride only 9261S(.S'8U Sampling Progru Emergency Response Sampling Indoor Air Sampling 0i0 Extended Monitoring Progru Sup ting Period July 17-24, 19S4 Sampled BY SCAQKD July, Aug., and Sept. 19S4 DOHS-TSCD Aug. Sept., Oct. 19B4 SCS Eng. for DOHS and EPA Table 1-19 (Continued) Sampling Activities Offsltei o HHU/OVA and flask suples indoor and at subsurface areas around selected evacuated hones Offsltei o Bulb and flask auples from under the sinks of 21 homes taken periodically Offsltei 1- Collected 24-hour composite air auples (Tedlar bags) from Indoors at 10 Priority I homes and I control 2- Collected 24-hour charcoal tube suples from indoors at 51 Prior ity 11 homes and 10 control 3- Continuous OVA monitoring In homes to parallel the composite sample collections 4- Periodic flask samples collected when OVA readings exceeded 100 ppm indoors 5- Subsurface probes (deep and shallow) monitoring with OVA meter, and flask collections when readings exceeded 1000 ppm Page 3 <Jf 4 Suple Analyses o Flask suples analysed for Vinyl Chloride and Methane o Bulb and flask samples analysed for 14 volatile organics, 3 in ert gases, arid CO (Analyses by ARB and SCAQMO) o Analysis for 10 volatile organic compounds using GC/MS o Analysis for Vinyl Chloride o For total hydrocarbons o Analysis for 10 volatile organics o Flask samples analyzed for 10 volatile compounds ZS61Sl-S'8d S o u rc e: tTable 3 -1 9 . "BHC L a n d f ill E n viro TM n e l E x p o .u r. C h . r . c t . r ix . t io n R .p o rt Waat Covina, C a lifo rn ia ," August 15, 1988, V o li e I . pgs. 3-97 to 3-100. Sampling Program Ambient Air Collections During Excavation of the Ephemeral Pond Surface Emissions Monitoring Prograe BKK Flare Station Ho. 1 LASUPER4/049 Sampling Period Harch 1905 Sampled By BKK April 1985 (1st Sampling) BKK Oct.-Hov. 1985 BKJt Oct. 19SS Certified Testing Laboratories for 8KK Table 3-19 (Continued) Sampllng Activities Oneltei o Tedlar bag samples collected both during days of excavation and days without excavation Onsitei o Integrated gas samples, each collected over a lOO'xSOO' area UBlng a flow sietering puatp Into a Tedlar bagi with a total of approximately ISO acres sampled onsite Page 4 of 4 Sample Analyses o GC analysis for Vinyl Chloride end Kethsne (analysis by Truesdail Labs) o Analysis for methane by BKKi and quantitative specletIon of approximately 10 percent of samples by Trusedail Labs for 30 volatile organic (14 detec ted) o Repeat of the let sampling, with approximately 150 acres sampled onsite Onsite o Grab samples II) Into Tedlar bags frest the inlet line and from one outlet (burner) o Analysis for methane by BKXi and quantitative speclatlon of approxiawtely 10 percent of samples by Hast coast Analytical Lab for 49 compounds (21 detec ted) o GH/HS analysis for 13 volatile organic compounds and polychlori nated biphenyls and related dioxin derivatives (data under review at this time sseisis'sa detected VOC's and indicated air as an exposure pathway for neighboring residents. Air Monitoring/Modeling Programs Used in the Quantitative :isk Characterization CH2MHill's retrospective quality assurance review identified 4 of the 15 air monitoring programs as relevant to quantitative analysis. Three of the four programs monitored ambient air around the B.K.K. Landfill; the fourth program monitored ambient air in the Los Angeles basin, in which the B.K.K. Landfill is located. Data from these four programs are used in the risk characterization and described in that section. GARB used the 1987 ambient vinyl chloride monitoring data from the landfill in an air dispersion model to estimate population exposure to vinyl chloride for the purpose of proposing to identify vinyl chloride as a toxic air contaminant. The risk characterization uses CARB's modeled data and describes the program in that section. Table 8 summarizes the programs and data used in the quantitative risk characterization. -40- cn CO ro co -V9- Program SCAQKD 1983-1987 Ambient Vinyl Chloride Monitoring Program DBSTSCP/CARB /SCAQMD 1992 Expanded Monitoring Program EPA-DHS 1984 Extended MonitorIns Program SCAQKD - CARS 198S Lo* Angelas Besln Air Toxics Monitorln( Prosram CARB ModelIns of 1987 Ambient Vinyl Chloride Honltorlns Data oeeistssa TABLE 8 AIR MONITOR!HC/MODELING PROGRAMS USED IN THE QUANTITATIVE RISK CHARACTERIIATIOH OF THE B.K.K. LANDFILL, WEST COVINA, CA flats Statfonfs} A, B, MYi located In residential nelshborhooda south, southeast of the landfill ' Chemlcaifs) Monitored i Vinyl chloride (detection limit 2 ppb) EJethod; 24-hour contlnuousi Tedlar bsgsi CC analysis) dally 6(81-1990 Ai considered In 1982 as the location for "worst-ease" meteorolotlc conditions Indoor air 10 Priority 1 evacuated homes El Monte, CARS A, B, MY 9i vinyl chloride, perchloroethylene, trichloroethylene, 1,2-dlchloroethane, chloroform, benaane, chlorobemene, trans-l,2-dlehloroethene, 1,1-dlchloroethena 9: vinyl chloride, perchloroethylene, trlchloroathylene, 1.1-dlchloroethene, 1.2-dlehloroethane, chloroform, bentene, carbon tetrachloride, 1,1,1-trlchloroethane Hi bensene, carbon tetrachloride, chloroform, ethylene dlbromlde, ethylene dlchlorlde, methylene chloride, perchloroethylene, toluene, 1,1,1trlchloroethane, trichloroethylene, vinyl chloride vinyl chloride (detection limit 2 ppb) 24-hour continuous; Tedlar bagsi Sunday through Thursday, July 19-Oetober IS) CC analysis, split samples analysed by CARB lab and SCAQKD lab 24-hour composite) Tedlar bags) CC-MS analysis not doicrltod in SCAQKD 1997 report SCAQKD's datsi 24-hour continuous) Tedlar bagsi CC analysis Summary Statist let si Monthly and annual geometric means, calculated by DBS from SCAQKD'a dally measurements Arithmetic means, taken from Table 11, DHSTSCP(CARB/SCAQKD 1983 report (a) Median values, taken from Table 6-13 and Volume 3 Appendix H-2 CH2KHU1 1988 report (b) Table V-l SCAQKD 19B7 report (c) Range of modeled concentrations, taken from Table II-S, CARB 1990 report (d) TABLE ft (continued) > Abbreviation*s SCAQHD DHS-TSCP CARB EPA cc CC-MS i South Coast Air QuslLty Mana*eownt District . Department of Health Service!-Toxic Subatancet Control Program California Air Resoureea Board - U. S. Environmental Protection Agency - gas chromatography - gaa chromatography-maa! apectrometry a, DHS-TSCP/CARB/SCAQHD, 'Ambient Air Monitoring and Health Risk Aaaeaament for Suspect Human Carcinogen* Around the MX Landfill In West Covina," March 1983. bt CH2MHU1, "BKK Landfill Envlronmantal Exposure Characterlcatlon Report Heat Covina, California,' Volume I Text end Volume 3 Appendix H-l, August 15, 1988. ci SCAQHD, 'The Hagnltude of Ambient Air Toxics Impacts Prom Existing Sources In the South Coeat Air Beelti,' 198T Air Quality Management Plan Revision, Working Paper Ho. 3, June 1987. d. CARS, 'Technical Support Document, Proposed Identification of Vinyl Chloride aa e Toxic Air Contaminant,' Draft Report Executive Summary and Part A, Kay 1990. -w - is6tstssy DOSE-RESPONSE ASSESSMENT The dose-response assessment defines the relationship between the "dose" (intake) of a chemical and the probability of a response, such as induction of a carcinogenic effect. EPA uses the term intake instead of dose because the information required to estimate "dose" (that is, the amount of a chemical absorbed and subsequently distributed to target organs) is usually not known. Numerical expressions of a chemical's dose-response relationship are called toxicity values: reference doses are values for noncarcinogenic effects; slope factors and unit risks are values for carcinogenic effects. This section identifies the chronic reference doses and inhalation unit risk values, current through June 1989, used in the risk characterization. Chronic Reference Doses Information about the amount of a chemical that produces a toxic response and the type of toxic response produced at a given dose level is obtained quantitatively from studies in experimental animals or observations in human epidemiologic investigations. Noncarcinogenic effects may result from acute or chronic exposures, and threshold levels are established below which no adverse health effect is expected. EPA has derived reference doses for chemicals based on different routes of exposure. The chronic reference dose (RfDc) is an estimate of the daily exposure to humans, including sensitive populations, that is likely to be without appreciable risk of adverse effects during a lifetime. Reference doses for carcinogens refer to effects other than the risk of cancer. Table 9 lists the reference doses for indicator -43- R&S151932 TABLE 9 REFERENCE DOSES* FOR INDICATOR CHEMICALS DETECTED IN OFFSITE SURFACE WATER AND AIR BKK LANDFILL. WEST COVINA. CA Indicator Chemical RfDc-0 mg/kg-day RfDc-0 ppb RfDc-I mg/kg-day RfDc-I Mg/m3 Non-Carcinogens Trans-1,2-Diehloroethylens' 1,1,1-Trichloroethane 1,1-Dlchlorostbane 1,2-Dichlorobenzene Chlorobenzene Ethyl Benzene Xylenes Toluene Phenol Copper Cyanide Selenium Zinc Carcinogens Arsenic Cadmium Chromium Lead Nickel Benzene Carbon Tetrachloride Chloroform 1,2-Dichloroethane 1,1-Dichloroethylene Methylene Chloride Perchloroathylene 1,1,2-Trichloroethane Trichloroethylene Vinyl Chloride 2E-2 9E-2 IE-1 9E-2 2E-2 IE-1 2E+0 3E-1 6E-1 1Z-0 2E-2 2E-3 2E-1 IE-3 5E-4 2E-2 7E-4 IE-2 9E-3 6E-2 IE-2 4E-3 - 700 3,150 3,500 3,150 700 3,300 70,000 10,500 21.000 1.300 700 105 7,000 35 17.5 MCL-50b MCL-Soh 700 MCL-lb 24.3 350 MCL-0.5b 315 2,100 350 140 MCL-5b MCL-0.5b 3E-1 IE-1 4E-2 5E-3 * 3E-1 mg/m3 2E+0 mg/m3 IE-3 " 70 1.050 350 140 17.5 350 300 2,000 2,100 130 70 3.5 700 3.5 - 1.75 -* - 70 -* * 2.45 - 35 - 31.5 * 210 * 33 - 14 -- "d a; Oral and Inhalation Chronic Reference Doses (RfDc-0, RfDc-I) in mg/kg-day are taken from Table A, "Health Effects Assessment Summary Tables, Third Quartar FY 1989," EPA July 1989, OERR 9200.6-303-(89*3). Chronic *3 Reference Dosaa in ppb and pg/mJ ara calculatad using conversion factors of 70 kg, 2 liters/day, and 20 m/dsy. b: MCL Maximum Contaminant Laval in Drinking Water, California Code of Regulations. Title 22, Division 4, Chapter IS. Sections 64*35 snd 64444.5. c; Trans-1.2-Dichloroathyl*na was reportedly not detected in ambient air in the 1982 Expanded Monitoring Program (DHS-TSCP/CARB/SCAQMD. 1983); CH2MH111 included data for the chemical in its 1988 report (Volume 5. Appendix H-2, CH2MH111, 1988). d: Noncarcinogenic effects of vinyl chloride occur at concentrations in air near or above 10,000 ppb which is much greater than ambient levels detected near the BKK Landfill, West Covina ("Technical Support Docun>ent, Proposed Identification of Vinyl Chloride as a Toxic Air Contaminant. Draft Report Fart B," CARB May 1990, pg. 1-2). R&S151933 -44- chemicals detected in offsite surface water and/or air around the B.K.K. Landfill. For those chemicals detected around the landfill that do not have a reference dose, the maximum contaminant level in drinking water is listed. Inhalation Unit Risk Values Cancer is considered a multistage process, and it is assumed that no threshold exists for substances that induce cancer. For carcinogens, risks are estimated as probabilities. Mathematical models used to derive estimates of risk associated with carcinogens are generally based on theories of carcinogenesis. EPA normally uses the linearized multistage model to extrapolate from observed high dose animal studies to expected low level environmental exposures. Values obtained from this extrapolation are expressed as slope factors or unit risks for a lifetime (70 years) exposure. Generally, after the data are fit to the appropriate mathematical model, the upper 95 percent confidence limit of the slope of the resulting dose-response curve is calculated. This value is known as the slope factor and represents an upper 95 percent confidence limit on the probability of a response per unit intake of a chemical over a lifetime. In some cases, slope factors based on human dose-response data use a "best" estimate (that is, the best fit dose-response line from a set of data) instead of the upper 95 percent confidence limit. The slope factor, expressed as (mg/kg-day)'1, is used when calculating the risk from actual daily dose in mg/kg to an individual. The unit risk is the risk per unit concentration of a chemical in the medium where human contact occurs. The unit risk, expressed as ppm'1, ppb-1, or -45- (ug/m3)*1, is used when calculating the risk from ambient air concentrations to which an individual is exposed. EPA recommends that numerical estimations of risk be coupled with the "weight-of-evidence" classification of a carcinogen. Risk assessors may arrive at different values for a carcinogen because they select different data sets or different extrapolation models. This health risk assessment uses the unit risk values derived by either EPA's Carcinogen Assessment Group or DHS's Air Toxics Section, and contained in California's "Air Toxics Assessment Manual, Table 3.15" (CAPCOA, 1987). Table 10 presents the unit risk values and the corresponding "weight-of-evidence" classification for the carcinogens detected at the B.K.K. Landfill. -46- R&S151935 TABLE 10 INHALATION UNIT RISK (IUR) VALUES FOR CARCINOGENS DETECTED AT BKK LANDFILL, WEST COVINA, CALIFORNIA Carcinogen AGENCY* IUR* <ng/m3)-1 EPAb etui Arsenic (inorganic) Cadmium Chrcmium(VI) Lead Nickel Benzene Bis-2-ehloroathylather Carbon Tetrachloride Chloroform 1,2-Dichloroethane 1,1-Dichloroethylane Methylene Chloride N-Nitrosodimethylamina Perchloroethylene 1.1,2,2-Tetrachloroethane 1.1,2-Trichlnroethane Trichloroethylene Vinyl Chloride EPA DBS DHS EPA DHS EPA DHS EPA MS EFA DHS EPA EPA EPA EPA EPA EPA 4.3E-3 1.2E-2 1.5E-1 4.BE-4 5.3E-5 3.3E-4 4.2E-5 2.3E-5 2.2E-5 5.0E-5 1.0E-6 1.4E-2 5.8E-7 3.8E-5 1.6E-5 1.3E-6 2.7E-6 A Bl A B2 A A B2 B2 B2 B2 C B2 B2 C C c B2 A a: Reference documents for tha valuaa listed wara derived by the Environmental Frotection Agency (EFA) or the Department at Health Services, Health Hazard Assessment Division, Air Toxics Section (DHS), and are given with Table 3.15, "Air Toxics Assessment Hsnual." California Air Pollution Control Officers Association, October 1987 pgs. 3.3-24 to 3.5-28. Values are current through June 1989. b: EPA weight of evidence classification: A, sufficient evidence in humans; Bl, sufficient evidence in animals. limited in humans; B2, sufficient evidence in animals, inadequate in humans; C, limited evidence in animals, inadequate in humans. Taken from EFA's Integrated Risk Information System (IRIS), June 1989. R&S151936 -47- RISK CHARACTERIZATION Risk characterization integrates the three previous components of a health risk assessment (hazard identification, exposure assessment, and dose'response assessment), to provide a numerical estimation of risk and a framework to relate the significance of the risk. This section estimates, for residents living near the B.K.K. Landfill, the risks associated with exposure to the concentrations of contaminants detected in offsite surface water and air. Individual excess lifetime cancer risks are calculated for carcinogens detected in three site-specific air monitoring programs, one Los Angeles basin air monitoring program, and one air modeling program. The population excess cancer burden is also estimated. Limitations and uncertainties of the estimated risk are discussed, and the significance of the risk estimate is explained. Risk Characterization of Exposure to Contaminants Detected in Offsite Surface Water Near the B.K.K. Landfill Most indicator chemicals detected in offsite surface water near the B.K.K. Landfill were detected in concentrations below their thresholds for noncarcinogenic effects (Table 11). Four indicator chemicals were detected in concentrations above their reference dose or maximum contaminant level: tine was detected at 17,000 ppb; arsenic, at 89 ppb; 1,2-dichloroethane, at 230 ppb; and vinyl chloride, at 40 ppb. Surface waters near the B.K.K. Landfill are not used for drinking water. Any exposure to contaminated -48- R&S151937 TABLE 11 COMPARISON OF INDICATOR CHEMICALS DETECTED IN OFFSITE SURFACE WATER, 1981-1985 TO ORAL CHRONIC REFERENCE DOSES BKK LANDFILL, WEST COVINA. CA Indicator Chemical Madlan Value ppb RfDe-Oralb ppb Non-Carclnogena Trana-1,2-Dichloroethylane 1.1.1-Trichloroathane 1.1-Dlchloroathana Chlorobenzene Xylanaa Toluana Fhanol Copper Cyanide Lead Selenium Tine Carcinogen* Araenic Cadmium Chromium Lead Nickel 1.1.2-Trichloroethana 1.2-Diehloroethan* 1,1-DichloroethyXene Chloroform Methylene Chloride Ferchloroethylene Trichloroethylene Vinyl Chloride 2.4 3.4 36 1.08 0.2 0.2 3,900 40 3 12 41 17,000 890 2 3 12 100 14 230 3.2 1.7 71 3.3 2.1 40 700 3.150 3,500 700 70,000 10,300 21,000 1,300 700 MCL-50 105 7,000 33 17.3 MCL-30 MCL-30c 700 140 MCL-0.Jc 313 330 2,100 350 MCL-5c MCL-0.5e a: Median Valuea are taken from Table 3-18, "BKK Landfill Environmental Expoaur* Characterization Report, We*t Covin*. California," CH2MH111, 1988, Volume I. pga. 3-90 to 3-94. (Table 6 of thi* report). b: Chronic Reference Dosea (RfDc-Oral) were calculated from chronic reference doae* Hated in Table A, "Health Effect* Aaaesament Suanary Table* Third Quarter FY 1989." EPA July 1989 (Table 9 of thi* report). c: MCL - Maximum Contaminant Level in Drinking Water. California Cod* of Regulation*, Title 22. Diviaion 4, Chapter 15, Section* 64435 and 64444.5. d; Maximum value taken from Table 5-21, CH2MH111, 1988, Volume I, pg*. 5-123 to 5-127. R&S151938 -49- surface water would have been infrequent, much less than two liters a day, and of limited duration. The risk associated with exposure to the concentrations of these contaminants in offsite surface water near the B.K.K. Landfill is n t considered significant. No numerical estimate of risk is made because no quantitative estimate of exposure can be made from the available information. RIsJs___Characterization----- of___ Noncarcinogens Detected in Air Near the B.K.K. Landfill From the limited sampling in air monitoring programs around th B.K.K. Landfill, only two noncarcinogen indicator chemicals were detected in air, both below their reference dose. 1,1,1-Trichloroethane was detected in 10 Priority I homes during the 1984 Extended Monitoring Program at a median value of 4 ppb; the inhalation chronic reference dose is approximately 192 ,,ppb. Trans-l,2-dichloroethylene, originally reported not detected in the 1982 Expanded Monitoring Program (DHS-TSCP/CARB/SCAQMD, 1983), was reported by CH2MH111 (Volume 5, Appendix H-2, CH2MH111, 1988); the median value was 1 ppb and the inhalation chronic reference dose is approximately 18 ppb. Noncarcinogenic effects of vinyl chloride occur at concentrations in air near or above 10,000 ppb, which is much greater chan ambient levels detected around the B.K.K. Landfill (CARB, Part B, 1990). Because the concentrations of contaminants detected in ambient air around the landfill do not exceed their thresholds for chronic reference doses, impacts from noncarcinogenic adverse health effects are not anticipated. -50- R&S151939 Risk Characterization of Carcinogens No threshold is assumed for carcinogens, therefore, this risk characterization estimates the risk of developing cancer from exposure to the carcinogens detected in air around the B.K.K. Landfill between 1982 through 1987. Data is taken from the following programs, which are summarized In Table 8 of the exposure assessment section: Site-specific programs (see Figure 7) SCAQMD's 1983-1987 Ambient Vinyl Chloride Monitoring Program - DHS-TSCP/CARB/SCAQMD's 1982 Expanded Monitoring Program - EPA and DHS's 1984 Extended Monitoring Program Los Angeles air basin program GARB and SCAQMD's 1985 Los Angeles Basin Air Toxics Monitoring Program Modeling program CARB's Modeling of 1987 Ambient Vinyl Chloride Concentrations Around the B.K.K. Landfill. Two measures are used to estimate the risk: the "individual excess lifetime cancer risk" and the "population excess cancer burden". These risk estimates are statistical concepts which represent plausible upper bound estimates of the probability of developing cancer due to lifetime (70-year) exposure. Th individual excess lifetime cancer risk implies that an individual remains in the same location for an entire lifetime, and that the concentrations of carcinogens remain unchanged. The population excess cancer burden represents the plausible upper limit on the number of excess cases of cancer which could occur in a population after exposure for a specific period of time. -51- R&S151940 S o u rce : CH2MH111. "BKK L a n d f ill Exposure C h a r a c te r iz a tio n R e p o rt. W est C o v in a , C a lif o r n ia . " A u g u st 15, 1988 Volume I , p. 5*165 (F ig u re 5 .2 1 ) and Volume FIGURE 7: Air Monitoring Programs, BKK Landfill, West Covina, CA (Based on CH2MHHI Fig. 5-21 and Plat 15) SAN BERNARDINO FREEWAY 1984 INDOOR . CONTROL HOME 3 MILE RADIUS (CENTER OF SITE | `T' .1 MILE RADIUS (BOUNDARY) LEGEND SCAOMD AMBIENT AIR MONITORING PROGRAM $ Long-Term Sampling Locations (>l Year) (J) Medium-Term Sampling Locations Q Short-Term Sampling Locations (<2 Months) A 1981 EXPANDED MONITORINO PROGRAM (A, B, D, E, FI and F2) 1984 EXTENDED MONITORINO PROGRAM Priority I Houses (Evacuated) & Control Home H Priority II Houses (Evacuated) Priority II Houses (Ncn-evacustcd) I I . P late 15. tcur i> ipej.sis'su Enlarged View of 1984 Extended Monitoring Program Numerical Estimations of Risk 1. Numerical Estimation - Individual Excess Lifetime Cancer Risk The risk calculation is expressed as: ECR -CxYRxEFxRFxURx 1/LT Where ECR - Excess lifetime cancer risk C - Concentration in /ig/m3 of the carcinogen; parts per billion were converted to micrograms per cubic meter (/ig/ra3) as follows (assuming 25C and 760 mm Hg pressure): pg/m3 - ppb x molecular weight 24.45 m3/^mole YR - Years of residence associated with exposure EF - Exposure factor, i.e., percent of time spent at home RF - Retention factor, i.e., percent of measured concentration absorbed in the lungs UR - Unit risk value LT - Human individual lifetime in years. Assumptions for this calculation are the following: persons have an average adult body weight of 70 kg and breathe 20 m3 of air per day; persons are at home 80 percent of the time (that is, the residential scenario assumes an annual exposure fraction of 292/365 days); persons retain 100 percent of the measured concentration; persons have an average 70 years lifetime. -53- R&S151942 a. Risk Characterization Using SCAQMD's 1983-1987 Ambient Vinyl Chloride Monitoring Program Data In 1977, SCAQMD measured ambient air at four plants which manufactured or used vinyl chloride in the Los Angeles Basin: Keysor-Century in Saugus; Union Carbide in Torrance; and B.F. Goodrich and Stauffer Chemical in Carson (SCAQMD, 1982). The B.K.K. Landfill received wastes containing vinyl chloride from these plants. In 1981, SCAQMD conducted limited sampling of landfill gas emissions at the B.K.K. Landfill and detected vinyl chloride at concentrations above the California ambient air quality standard of 10 ppb. Because vinyl chloride is a human carcinogen, it became the landfill gas contaminant of primary concern. Vinyl chloride is the only contaminant for which there are continuous monitoring data from 1981 to the present. SCAQMD _t>egan monitoring in residential neighborhoods around the B.K.K. Landfill: Station A, established in 1981, was located at the intersection of Marlena and Nogales Streets, 450 feet southeast of the property line; Station B, established in 1981, was located on Lynn Court, immediately adjacent to the southern property line; Station MY, established in June 1984, was located on Myra Court, 150 feet southeast of the property line. Because the detection limit for vinyl chloride was lowered from 10 ppb to 2 ppb in 1983, comparison with data prior to 1983 is limited. -54- R&S151943 Samples were collected, as 24-hour continuous daily samples in Tedlar bags and analyzed at SCAQMD's laboratory by gas chromatography. Table 12 presents the monthly and annual geometric means of vinyl chloride at Stations A, B, and MY for the years 1983 through 1987. DHS staff calculated the geometric means from SCAQMD's daily measurements. Measurements of vinyl chloride below the detection limit of 2 ppb were assumed to be at the detection limit. Figure 8 was generated from this data, and shows that both the maximum value of vinyl chloride detected and the frequency of detection have declined since 1985. Applying the present risk calculation to the 1987 annual geometric mean of vinyl chloride from Station MY (the highest value), and assuming a 70-year exposure to this level of vinyl chloride, the individual excess lifetime cancer risk is estimated to be 1.5 x 10"5, or approximately 1 to 2 in 100,000. -55- R&S 151944 TA10I 12 VINYL CHLORIDE IN AMSirrrr AIR (ppb) - 1983-1987 MONTHLY AND ANNUAL GHWETRIC MEANS SCAOMD ttJHIIORIKG STATIONS AROUND EOL LANDFILL, WEST COVINA, CA month STATION 1983 JAN FEB MAR APR MAT JUNE JULY AUG SEPT OCT NOV DEC A 3.8 3.6 2.3 2.1 2.6 2.3 3.A 2.5 3.5 2.9 2.2 2.7 ANNUAL 2.8 1984 3.1 2.8 3 2.5 3.2 2.8 NS 3.7 4.7 4.4 3.7 3.6 3.3 1985 3.9 3.4 4.7 3 2.6 2.9 2.9 4 3.2 3.2 2.6 3.7 3.3 1986 2.7 2.6 2.6 2.3 2.3 2.5 2.6 2.3 2.2 2.2 2.1 2 2.4 JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC ANNUAL 8 3.4 2.8 2.5 2.4 2.1 2.1 3.7 3.1 2.5 3.4 3.4 4.2 2.9 73 3.7 3.1 3.9 2.5 3.5 . 2.5 4.6 2.3 3.5 2.3 ND 2.3 2.3 2.7 2.7 2.5 3.6 2.8 5.1 2.3 3.8 2.8 3.8 2.6 2.1 2.5 2.2 2 2.1 2.1 2.2 2.1 2.2 2.1 2 2 2.1 JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC ANNUAL ND 6.6 3.1 ND 4.4 3.8 ND 4.5 3.2 HD 3.8 2.3 ND 3 2.7 ND 3.9 3.2 ND 4.1 3.2 4.1 4.8 3.2 4.5 4 2.6 5.3 3.9 2.6 5.1 3.9 3.3 3.8 6.3 2.8 4.5 4.3 3.0 ANNUAL TOTALS 2.8 3.9 3.3 2.5 1987 2 2.1 2.3 2.6 2.1 2.1 2.3 2.2 2.6 2.4 2.1 2.4 2.3 2.1 2 2 2.1 2 2 2 2.2 2 2 2 2 2.0 2.3 2.4 2.9 3 2.6 2.3 2 2.8 3.2 2.6 3.1 3.1 2.7 2.3 R&S 151945 NOTE: DHS staff calculated monthly and annual geometric maans from SCAOMD'a daily maaaurament* of vinyl chloride, ND - No data was received. Measurements below the detection limit of 2 ppb ware assumed to be at the datection limit. Station A - Mariana & Nogales Streets; Station B - Lynn Court; and Station MY Myra Court, aatablisbad Juna 1984. -56- FIGURE 8 VINYL CHLORIDE IN AMBIENT AIR 1983-1987 STATION A MONTHLY MONITORING DATA BKK LANDFILL, WEST COVINA, CA VINYL CHLORIDE - BKK - 1985-1987 MAXIMUM VALUE VINYL CHLORIDE - BKK 1983-1987 NOTE: DHS staff generated this* figures from daily measurements of vinyl chloride by SCACMD at Station A. -57- R&S151946 If a value of 1 ppb (chat is, half the detection limit) is substituted for values of vinyl chloride below the detection limit, the 1987 geometric means by station would be: A, 1.4 ppb; B, 1.1 ppb; and MY, 1.4 ppb. The annual geometric mean of all three stations would be 1.3 ppb. Using the value from Station MY, 1.4 ppb or 3.6 pg/m3, the individual excess lifetime cancer risk would be 7.8 x 10"6, or approximately 8 in 1,000,000. Vinyl chloride emissions from the B.K.K. Landfill appear to have changed over time. Years used to compare the changes in vinyl chloride emissions are: - 1982, at which time the first health risk assessment was conducted; - 1983, at which time the detection limit for vinyl chloride was lowered to 2 ppb; - 1984, at which time homes were evacuated due to subsurface migrati n of landfill gas, leading to an improved landfill gas collection system; - 1987, at which time mitigation measures were further lowering vinyl chloride emissions from the facility. Table 13 evaluates the 70-year risk over these changing exposure periods. A one-year exposure period is defined for data from 1983 through 1986. The 1982 data represent the following: the initial seven-year period for which waste disposal records are available (1975-1982); the landfill expansion from 40 acres to 140 acres; and -58- R&S151947 TABLE 13 INDIVIDUAL EXCESS LIFETIME CANCER RISE* SCAQMD AMBIENT VINYL CHLORIDE MONITORING PROGRAM BEE LANDFILL. WEST COVINA. CALIFORNIA 19B2b M/m3 (ppb) 19B3C M/D3 (ppb) 19B4d M/d3 (ppb) 1985d m/d3 (ppb) lose4 M/d3 (ppb) 1987d M/D3 (ppb) Total Cve YR ECR 18.6 (7.3) 7 4.0 x 10'6 7.2 (2.8) 1 2.2 x 10'7 11.5 (4,5) 1 3.5 X 10'7 11.0 (4.3) 1 3.4 x 10~7 7.7 (3.0) 1 2.4 x 10'7 6.9 (2.7) 59 1.3 x 10"5 70 1.8 x a; Calculated by ECR - Cve x YR x EF X RF X UR X 1/LT idlera 3ECR - Excess lifetime cancer risk Cve " Concentration In m/d'' of vinyl chloride YR * Years of residence associated with exposure EF " Exposure factor, i.a. parcant of time at bona (80S) RP - Retention factor, i.a. percent of oaaaurad concantratlon absorbed in tba lunfa (100Z) UR - Unit riak value for vinyl chloride: 2.7 x 10~8 Cm/d3)'1, taken from Table 3.15, "Air Toxica Aaaeaaaent Manual," California Air Pollution Control Officer`a Aaaociation, October 1987, p. 3.5*28. Value currant through Juno 1989. LT - Human individual lifetime in yaare (70) b: Mean value. Station A. Table II, "Ambient Air Monitoring and Health Riak Aaaeaament for Suepoct Bubid Carcinogena Around the BEE Landfill in Weat Covina." DHS-TSCP/CARB/SCACMD, March 1983, p. 16 (Appendix B of thia report), c: DHS ataff calculated the annual geometric mean from daily maaauremanta of vinyl chloride by SCAQMD at Stations A and B (Table 12-of this report). d: DBS staff calculated the annual geometric mean from daily measurements of vinyl chloride by SCAQMD at Station MY (Table 12 of this report). R&S151948 -59- the increased residential construction along the southern border. The 1987 measurements are projected for the remaining 59-year period, although mitigation measures may be expected to lower vinyl chloride emissions. Applying the present risk calculation to the data specified in Table 13, the individual excess lifetime cancer risk ov r the changing exposure periods is estimated to be 1.8 x 10"5, or * approximately 2 in 100,000. b. Risk Characterization Using DHS-TSCP/CARB/SCAQMD's 1982 Expanded Monitoring Program Data During July to October 1982, DHS-TSCP, CARS and SCAQMD conducted a 90-day study to monitor ambient air around the B.K.K. Landfill for nine VOCs. The study was the first health risk assessment of the landfill. A summary of the report as well as a copy of the report are provided in the Appendix. Three monitoring stations were located in residential neighborhoods around the landfill (A and B to the south; F to the north); two monitoring stations were located on the landfill (D at the entrance, E at the highest elevation); and SCAQMD's monitoring station in Pico Rivera, nine miles to the southwest, was selected as the control station C. The selection of Pico Rivera as a residential control site has since been questioned because of the influence from industrial emission sources in Pico Rivera. In 1982 it was considered to be the closest established monitoring station for which routine data had been -60- R&S151949 collected over a period of years, and an upwind location. Stations A, B, D, E, and F are shown in Figure 7. The study defined the exposure period as the previous seven years (1975-1982) reflecting the seven year period for which waste disposal records were available, the landfill expansion from 40 acres to 140 acres, and the increased residential construction along the southern border. Continuous 24-hour samples were collected in Tedlar bags Sunday through Thursday. Split samples were taken and analyzed by two laboratories, SGAQMD's laboratory and CARB's southern laboratory branch (Haagen-Smit). Of the nine compounds monitored, seven were detected. Mean values from each laboratory were reported. CH2MHill's 1988 report has conflicting information about the program's data for benzene. DHS-TSCP/CARB/SCAQMD reported that benzene was detected by one laboratory which had a detection limit of 2 ppb, but not by the second laboratory which had a detection limit of 20 ppb. Benzene was included in their health risk assessment. CH2MHU1 listed the detection limits for benzene from the two laboratories as 10 ppb and 20 ppb, and excluded benzene from its exposure assessment. CH2MH111 did not document the discrepancy between the 2 ppb and 10 ppb detection limit for the one laboratory. For this risk characterization, data from Station A are used. Topographic and meteorologic data suggested that the location of -61- 3> 9 CO COOl Station A received higher contaminant levels than the other stations (B, D, E, and F), and represented a "worst-case" scenario. Applying the present risk calculation to the 1982 Station A measured data, assuming the seven-year exposure period defined in the program (1975-1982) and an additive effect of the carcinogens, the individual excess lifetime cancer risk is estimated to be 1 in 10,000. This estimate includes the benzene data reported by one laboratory. Deleting the benzene data because of the discrepancies in detection limits reduces the estimated risk to approximately 5 in 100,000 (Table 14). c. Risk Characterization Using EPA and DHS' 1984 Extended Monitoring Program Data (Indoor Air Monitoring, Priority I Evacuated Homes) In July 1984, 19 homes along the southern and southeastern perimeter of the B.K.K. Landfill were evacuated when methane, from lateral subsurface migration of landfill gas, was detected at concentrations above the lower explosive limit (50,000 ppm). The Southern California Gas Company detected and identified the methane gas from the landfill during a routine survey (every four years for residential distribution piping systems). The landfill gas served as a transport medium for VOC's deposited at the facility. EPA and DHS developed the "Extended Monitoring Program" to investigate the hazards: 10 homes and 1 control home were designated Priority I, requiring indoor air monitoring for 9 VOC's and total hydrocarbons; 51 occupied homes and -62- R&S151951 TABLE 14 INDIVIDUAL EXCESS LIFETIME CANCER RISE* DHS-TSCP/CARB/SCAOMD 1982 EXPANDED MONITORING PROGRAM BEX LANDFILL. WEST COVINA, CA Carcinogen Molecular Weight C-Station A^ ppb ng/m3 Unit Risk (Mf/m3)-1 Cancer Risk EPAd Clas* Chloroathene (Vinyl Chloride) Perchloroethylens (FCE) Trichloroathene (TCE) 1,1-Dichloroathene (Vinylidene Chloride) 1,2-Dichloroethane (Ethylene Dichloride) Trichloromathane (Chloroform) Bensons 62.3 163.83 131.4 96.93 98.96 119.39 78.11 7.3 16.6 3.7 23.0 1 5.37 1.3 3.13 3 12.1 0.3 2.44 4.8 . 13.3 Total Excess Lifetime Cancer Risk Including Bansan* Total Excess Lifetime Cancer Risk Excluding Benzene 2.7E-6 3.8E-7 1.3E-6 5.0E-5 2.2E-5 2.3E-5 3.3E-5 4.0E-6 1.2E-6 3.6E-7 2.1E-3 2.1E-5 4.5E-6 6.5E-3 A C B2 C B2 B2 A 1.2E-4 5.21-5 a: Calculated by ECR -CxYRxEFxRFxURx 1/LT where ECR " Excaaa lifetime cancer risk _ " Concentration m ug/m3 YR - Years of reaidenee aaaoeiatad with axpoaure (7) EF - Exposure factor, l.a. percent of time at borne (80S) RF - Retention factor, l.a. percent of measured concentration abaorbed in the lungs (10QX) UR - Unit risk value LI - Hums individual lifetime in yaara (70) b: Mean values, Station A, Table II, "Ambient Air Monitoring and Health Risk Assessment for Suspect Bunin Carcinogens Around the BEE Landfill in West Covina." DBS-TSCF/CARB/SCAQMD, March 1983, pg, 16. (Appendix B of this report). c: Values taken from Table 3.13 of the "Air Toxics Assessment Manual," California Air Pollution Control Officers Association. October 1987, pgs. 3.3-24 to 3.3-28. Values current through June 1989. d: EPA weight of evidence classification: A, sufficient evidence in humans; Bl, sufficient evidence in animals, limited in humans; B2, sufficient evidence in animals, inadequate in htssana; C, limited evidence in animals, inadequate in huaans. Taken from EPA's Integrated Risk Information System (IRIS), June 1989. R&S151952 -63- 10 control homes were designated Priority II, requiring monitoring for vinyl chloride; and 90 subsurface landfill gas probes were installed onsite and offsite to monitor for total hydrocarbon levels. Field technical support and data quality assurance support for the program were provided by the EPA FIX contractor (Ecology and Environment, Inc,). Laboratory analyses were done by West Coast Analytical Laboratories. Data management support was provided by an EPA contractor, Tech Law. Priority I homes were monitored in October 1984 for the following nine VOC's: chloroform, 1,1-dichloroethylene, benzene, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, perchloroethylene, trichloroethylene, and vinyl chloride. Composite 24-hour samples were collected in Tedlar bags and analyzed by gas chromatography-mass spectrometry. Data for Priority II homes were not available and not discussed by CH2MH111. CH2MHill prepared Table 15 as a summary of the data for the Priority I homes and the control home, and recorded the data for the program in Volume 5 Appendix H-2. CH2MHill did not list benzene, as seen in Table 15, because detections were attributed to laboratory contamination. No documentation or explanation of the laboratory contamination was provided. Data for benzene is added as a footnote to Table 15. Carbon tetrachloride and chloroform were not detected in any of the ten Priority I homes, and are not included in the risk -64- TABLE 15 (CH2MHILL) Table 6-13 SUMMARY OF 1984 INDOOR MONITORING IN PRIORITY X HOMES AND A CONTROL HOME Chemicals PrioriT%p& %?gfs (10) a No. Median Maximum No. Median Maximum 1,1-Dichloroethylene 1,2-Dichloroethane 1,1,l-Trichloroethane Carbon Tetrachloride Chloroform Perchloroethylene Trichloroethylene Vinyl Chloride 75 <1 75 3 75 4 75 <1 75 <1 75 2.5 75 1.5 75 <4 2 14 14 <1 <1 21 6 7 4 <1 4 <1 43 4 <1 4 <1 4 1.5 4 <1 4 <4 <1 <1 4 <1 <1 2 <1 <4 Notes: Data source is the 1984 Extended Monitoring Program. Values presented with < symbol are detection limits. *Number of samples. Source: CH2MH111, Table 6*13, "BKK Landfill Environmental Expoaure Charactarization Report. Heat Covina, California." Auguat 13, 1988, Volume 1. P. 6-43. Benzene data in CH2MB111 Volume 3, Appendix B-2, 1988, are the following; Priority I homei - 70 samplei, median value 7 ppb, mavinnim value 29 ppb; Control home - 2 eamplez, 4 and 6 ppb. Carbon tetrachloride and chloroform ware not detected in any of the 10 Priority I home*. A detection limit of 4 ppb for vinyl chloride ia not aubatantiated by recorded valuea in Volume 3, Appendix H-2. R&S151954 -65- characterization; the values in Table 15 for carbon tetrachloride and chloroform are the detection limits for the compounds. A detection limit of A ppb for vinyl chloride in Table 15 is not substantiated by recorded values in Volume 5, Appendix H-2: a value of 1 ppb is recorded for one home and a value of 2 ppb is recorded for thr e homes. Because the concentrations detected in the Priority I homes appear somewhat similar to the concentrations detected in the control home, analysis of variance (ANOVA) was performed to determine if there was a difference. ANOVA is a statistical technique that investigates the contribution of one or more factors to the variation in an outcome of interest. For the seven compounds detected in the Priority I homes (vinyl chloride, 1,1-dichloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, perchloroethylene, trichloroethylene, and benzene), 3-way ANOVA shows that concentrations detected in the Priority I homes were significantly higher than concentrations detected in the control home (p <0.039). Excluding benzene, 2-way ANOVA of the six compounds shows a significant difference in the concentrations detected in the Priority I homes (p <0.006). Both analysis controlled for sample date/calendar period, indicating that the difference was not due to the day the sample was taken. (Appendix E contains a more detailed description of the analyses.) Whether or not there were additional sources of the compounds within the homes cannot be determined from the available data. R&S151955 -66- Table 16 applies the present risk calculation to the six carcinogens detected in the Priority I homes. (1,1,1-Trichloroethane, a Class D carcinogen, is not included in the risk calculation; the inhalation reference dose is 192 ppb.) A one-year exposure period of January to December 1984 is assumed since all evacuated homes were allowed to be reoccupied by December, and elevated levels of methane and landfill gas may have been present for a short time prior to being detected by the routine survey. Assuming an additive effect of the carcinogens, the individual excess lifetime cancer risk is estimated to be 2 in 100,000 including benzene, and approximately 6 in 1,000,000 excluding benzene. d. Risk Characterization Using CARB and SCAQMD's 1985 Los Angeles Basin Air Toxics Monitoring Program Data Pursuant to California's toxic air contaminant program (Health and Safety Code, Section 39650 et seq), CARB and SCAQMD initiated programs in 1985 to monitor selected VOC's at specific locations within the Los Angeles basin. Results were reported in "The Magnitude of Ambient Air Toxics Impacts From Existing Sources in the South Coast Air Basin" (SCAQMD, 1987). Air monitoring stations for SCAQMD were located in Anaheim, Azusa, Burbank, and Lennox; monitoring stations for CARB were located in El Monte, Long Beach, Los Angeles, Rubiodoux and Upland (Figure 9). Compounds selected for monitoring were: benzene, carbon tetrachloride, 1,2-dibromomethane, 1,2-dichloroethane, methylene chloride, perchloroethylene, toluene, 1,1,1-trichloroethane, -67- n w Ol O0C5Oi Carcinogen TABLE 16 INDIVIDUAL EXCESS LIFETIME CANCER RISE* EPA and DBS 1964 EXTENDED MONITORING PROGRAM BKK LANDFILL. WEST COVINA, CA Molecular Haight Median'3 ppb ma/b3 Unit Risk0 (si/a3)*1 Cvicar Risk ' EPAd Class Vinyl Chloride Ferehloroetbylene Trichloroetbene 1,1-Dichloroethene 1,2-Dichloroethane Benzene 62.3 163.83 131.4 96.93 98.R6 78.11 4 2.3 1.3 1 3 7 10.2 17.0 8.1 4.0 12.1 22.4 Total Excess Lifetime Ceneer Risk Including Benzene Total Excess Lifetime Cancer Risk Excluding Benzene 2.7 E-6 5.8 E-7 1.3 E-6 3.0 E-5 2.2 -3 3.3 E-5 3.1 E-7 1.1 E-7 1.2 E-7 2.3 E-6 3.0 E-6 1.4 E-5 A C B2 C B2 A 2.0 E-5 5.8 E-6 a: Calculated by ECR ~CxYRxEFxRFxURx 1/LT where ECR - Excess Lifetime cancer risk C - Concentration in ug/m3 TR " Years of residence associated with exposure (1) EF " Exposure factor, i.e. percent of time at hone (80Z) RF - Retention factor, i.a. percent of meaaured concentration absorbed in the lungs (1001) UR - Unit risk value LT - HvMan individual lifetime in years (70) b: -Median values taken from Table 6-13, "BKK Landfill Environmental Exposure Characterization Report, Weat Covina, California," CB2MH111, 1968, Volina I, p. 6-43. c: Values taken from Table 3.13, of the "Air Toxics Assessment Manual," California Air Pollution Control Officers Association, October 1987, pgs. 3.3-24 to 3.S-2B, Values current through June 1989. d: EPA weight of evidence classification: A, sufficient evidence in humans; Bl, sufficient evidence in animals, limited in humans; B2. sufficient evidence in animals, inadequate in humans; C, limited evidence in animals, inadequate in humans. Taken from EPA's Integrated Risk Information System (IRIS), June 1989. R&S151957 fifl- R&S151958 SMH1WN MIT) FIGURE 9 (SCAQMD) FIGURE V-l AMBIENT AIR TOXIC MONITORING SITES IN THE SOUTH COAST AIR BASIN Sourca: South Coast Air Quality Management District, Figure V-l, "The Magnitude of Ambient Air Toxics Impacts From Existing Sources m the South Coast Air Basin," June 1987, p. V-2. -69- trichloroethylene, chloroform, and vinyl chloride, (Table 17). Values obtained from these programs provide "background" levels in the Los Angeles air basin. Sampling methods and analysis were not described in the report. CH2MH111 used data from the four SCAQMD monitoring stations in its 1988 report. This risk characterization uses data from CARB's El Monte station. Of all nine locations shown in Figure 9, El Monte appeared to be more representative of ambient air conditions which might exist around the B.K.K. Landfill. The Azusa station was not considered representative because of its proximity to mountains. With the exception of vinyl chloride, the carcinogens detected in ambient air near the B.K.K. Landfill have also been detected in ambient air in the Los Angeles basin. For the carcinogens detected near the B.K.K. Landfill, Table 18 applies the present risk calculation to the annual average ambient concentrations of those carcinogens also detected at El Monte Station in the las Angeles basin. Assuming a 70-year exposure and an additive effect of the carcinogens, the individual excess lifetime cancer risk for the area near the El Monte Station is estimated to be approximately 7 in 10,000. Benzene emissions have the greatest cancer risk impact in the Los Angeles basin, corresponding to an upper-bound risk of 1 in 10,000 to 1 in 1,000 (SCAQMD, 1987). Benzene emissions are attributed almost -70- TABLE 17 (SCAQMD) TABLE V-l 1885 ANNUAL AVERAGE AMBIENT AtR. CONCENTRATIONS OF VARIOUS TOXIC ORGANIC GASES IN THE SOUTH COAST AIR BASIN* (concentration in ppbr) Pollutant SCAQMD ARB Ana heim Aauaa Burbank Lennox El Long LA Rubi- Upland Mont* Beach doux BENZENE At*. Cone. Std. Dr. Dataction Limit Sampla Sia*/# < DLe Data Category^ 1.7-J.8 l. 2.0-4.0 34/10 B 1.0-2.6 .82 1.0-4.0 21/13 B 2J1-3.0 14 1.0-3.0 23/9 B 1.7-2.8 1.5 2.0-3.0 23/10 B 4.8 2.6 .5 39/0 A 44 1.9 .5 25/0 A 44 2.3 .5 23/0 A 24 14 .5 24/0 A 3.4 14 4 22/0 A CARBON TETRACHLORIDE At*. Cone. Std. Dot. Dataction Limit Sampla Sis*/# < DL Data Catagory 42 .038 .018 32/0 A .13 .036 JUS 18/0 A .10 JUS JUS 30/0 A .11 .033 .016 20/0 A JNS J>24 .004 36/0 A 40 JU4 .004 22/0 A .11 J)16 .004 21/0 A .099 .015 .004 30/0 A 42 JITS .004 20/0 A CHLOROFORM At*. Cone. Std. Dav. Dataction Limit Sampla Sis*/# < DL Data Category .045-.30 * .03-1.0 33/31 C .0S3-.28 .03-1.0 18/18 C .018-.24 .077-.5 20/20 C .063-.27 .077-.89 30/18 C .063 .023 .02 36/0 A .062 .02$ .03 22/0 A 41 .090 .03 21/0 A .053 .028 .02 20/0 A .071 .045 .02 20/0 A ETHYLENE DIBROMIDE At*. Cone, (ppt) Std. Dar. (ppt) Dataction Limit (ppt) Sample Sisa/# < DL Data Category 5-100 * 100 22/21 C 0-100 100 18/19 C 0-100 100 30/20 C 0-100 100 20/30 C 'S-S 4 5 36/26 B 4-8 9.0 5 22/15 B 2-6 2.0 5 21/14 B 2-6 1.4 5 20/16 B 3-5 1.0 5 20/9 B ETHYLENE DICHLORIDE At*. Cone. Std. Dar. Dataction Limit Sampla Sis*/# < DL Data Category 0-17 * 2.1-28 22/22 C 0-14 4.0-28 19/19 C 0-18 4.0-28 20/20 C 1.0-18 0 4.0-28 30/19 C R&S151960 -71- TABLE V-l (continued) Pollutant SCAQMD ARB Anahum Aauaa Burbank Lennox El Lone LA Rubi- Upland Mont* Beach doux MKTHYLfiNE CHLORIDE Ava. Cone. Std. Dev. Dataction Limit Sample Siaa/# < DL Data Category PTOCHLOROETHYLENE Ava. Cone. Std. Dav. Dataction Limit Sample SUa/# < DL Data Category 3.1 3.4 .3 33/0 A 2.0 1.S .2 10/0 A 2.7 i.e .2 30/0 A 2.3 3.5 .3 30/0 A 5.1 4.S-4.7 2.5 3.9 .005 .005 35/0 22/1 AA 3.5 2.2-2.S 2.0 1.9 .006 .005 21/0 30/4 AB 2.7-3.S 1.7 .005 20/3 B 1.5 .86 .01 36/0 A 1.0 .56 .01 22/0 A 1.2 .91 .01 21/0 A .46 .32 .01 20/0 A .70 .45 .01 20/0 A TOLUENE Ava. Cone. Std. Dev. Dataction Limit Sample Sim/# < DL Data Cateforjr 4.0-5.6 3.9 3.0-6.0 34/S B 2.5-4.9 2.3 3.0-7.0 31/11 B 5.5-S.7 3.0 S.0 33/5 B 3.5-5.3 4.2 .40-5.0 33/11 B 1 1 1-TRICHL0R0ETHANE Ave. Cone. Std. Dav. Detection Limit Sample Siaa/# < DL Data Category 3.3 1.4 .33 33/0 A 2.0 1.7 .23 10/0 A 3.3 1.7 .33 30/0 A 2.5 1.5 .23 20/0 A 7.1 4.7 .02 35/0 A 3.0 2.1 .03 22/0 A 2.4 2.8 .03 31/0 A 1.1 .73 .02 20/0 A 1.6 1.1 .02 20/0 A TRICHLOROETHYLENE Ava. Cone. Std. Dev. Dataction Limit Sample Site/# < DL Data Category .33-.35 .33 .30-.90 23/7 B .1G-.33 .25 .11-90 19/8 B .30--45 .73 .12-22 20/7 B .20-.23 .23 .12-.IS 20/15 B .40 .25 .02 36/0 A .29 .20 .02 23/0 A .34 .22 .02 21/0 A .10 .06 .02 20/0 A .37 .17 .02 20/0 A VINYL CHLORIDE Ava. Cone. Std. Dev. Detection Limit Sample Site/# < DL Data Category 0-3.0 3.0 34/24 C 0-2.0 2.0 21/21 C 0-2.0 3.0 24/34 C 0-3.0 < 2.0 34/23 C -72- r &S151961 Pollutant TABLE V-l (continued) s cAqMD ARB Anahun Asuia Burbank Lennox El Lone LA Rubi- Upland Mont** Beach doux BENZOfAlPYRENE (from EPA monitoring network) Ava. Cone, (ng/mj Std. Dev. Det. Lim. (ng/m*) Sample Sis*/# < DL Data Category .7S .17 .33 31/0 A .73 .0079 33 13/0 A * Blank* indicat* no data avaiiabl*. ~ kuipt of arithmetic annual average* defined a* follow*: firtt Mtimat* la the average a**uming all aub-deteetion limit observation* equal aero; aecond eatimat* ia the average aaauming all aubdetection limit observation* are equal to the detection limit concentration. Standard deviation* were calculated using only the observation* above detection limits; if more than BO percent of the observation* were below detection limits, standard deviations wet* not calculated. k Detection limit* for some SCAQMD-measutcd pollutant* reported a* rang* became limits changed from sample to sample depending on analytical condition*. See text for further explanation. c "Sample Sis*/# < DL's (the total number of samples taken over the year) / (total number of the** samples with concentrations below minimum detectable limits). 5 Data Category codes for SCAQMD and ARB data are defined as: A - Most of the data above detection limits (>90%), C - Very few of the data point* are above detection limits (<10%), and B - Several data point* fall above and below detection limits. * * standard deviation not calculated for Data Category C. Source: South Coast Air Quality Management District, Table V-l, "The Magnitude of Ambient Air Toxic* Impacts From Existing Sources in the South Coast Air Basin." 1987 Air Quality Management Flan Revision Working Psper No. 3, June 1987, Pgs. v-4 to V-6, R&S 151962 -73- TABLE 18 INDIVIDUAL EXCESS LIFETIME CANCER RISK* CARCINOGENS DETECTED AT EL MONTE STATION, 1383 LOS ANGELES BASIN AIR TOXICS MONITORING PROGRAM AND ALSO DETECTED NEAR THE BKK LANDFILL. WEST COVINA. CA Cercinogen Molscular Weight Benxene Vinyl Chloride Perchloroethylene Trichloroethylene 1,2-Dichloroethee Chloroform 78.11 62.3 163.83 131.* 98.96 119.39 Total Excess Lifstims Csncsr Risk El Monteb ppb Mg/m3 Unit Risk (Mg/m3)"1 *.9 - 1.6 0.40 " 0.06 15.7 * 10.9 2.1 .3 3.3 -5 2.7 E-6 5.8 E-7 1.3 E-6 2.2 E-3 2.3 E-5 Cancer Risk EPAd Class 6.7 E-4 " 3.1 E-6 2.2 E-6 5.3 E-6 A A C B2 B2 B2 e1.6 E-* a: Calculated by ECR -CxYRxEFxRFxURx 1/LT where ECR " Excess lifetime esneer risk 3C " Concentration in MS/m YR - Years o rasldanca associated with exposure (70) EF - Exposure factor, i.e. percent of tine at hone (SOI) RF - Retention factor, i.e. percent of measured concentration absorbed in the Lungs (1001) UR - Unit risk value LT " Human individual lifetime in years (70) b: Values tsken from 1 Monte Station, Table V-l, "1983 Annual Average Ambient Air Concentrations of Various Toxic Organic Gases in the South Coast Air Basin," SCAOMD, 1987, pgs. V-* to V-6. c: Values taken from Table 3.13 "Air Toxics Assessment Manual," California Air Pollution Control Officers Association, October 1987, pgs. 3.3*2* to 3.3-28. Values current through June 1988. d: EPA weight of evidence classification: A, sufficient evidence in hissans; Bl, sufficient evidence in animals, limited in humans; B2, sufficient evidence in animals, inadsquste in humans: C, liaitsd evidence in animals, insdaquats in humans. Taken from EPA'a Integrated Risk Information System (IRIS), June 1989. R&S151963 74- equally to mobile sources (motor vehicles) and area sources (gasoline marketing, stationary gasoline engines, crude oil production, and agricultural burning). In two earlier characterizations, (the 1982 Expanded Monitoring Program and the 1984 Extended Monitoring Program) benzene could be excluded from the risk calculation because of discrepancies with the data. The data in this characterization suggest that risks presented by exposure to benzene are more significant from ambient sources than from the B.K.K. Landfill. e. Risk Characterization Using CARB's Modeling of 1987 Ambient Vinyl Chloride Concentrations Around the B.K.K. Landfill GARB used monitoring data from the B.K.K. Landfill in an air dispersion model to estimate population exposure to vinyl chloride for the purpose of proposing to identify vinyl chloride as a toxic air contaminant (CARB, 1990, Draft Document). CARB is the state agency responsible for identification of toxic air contaminants. A toxic air contaminant is subject to a different regulatory process than an ambient air quality standard. A toxic air contaminant is an air pollutant which may cause or contribute to increased morbidity r mortality, or which may pose a present or potential human health hazard (California Health and Safety Code Section 39655). Identification of vinyl chloride as a toxic air contaminant allows CARB to develop control strategies that reduce vinyl chloride air levels far below 10 ppb. -75- CARB used the Industrial Source Complex Short Term (ISCST) Gaussian model to estimate vinyl chloride concentrations and expos d population. This model does not allow direct inference of dist.-.-ce. In this model, the B.K.K. Landfill was represented as an area source in the center of a grid of 41 one-square-kilometer cells (that is, a grid of approximately 25 square-miles). For each square-kilometer cell, annual average vinyl chloride concentrations were estimated using SCAQMD's 1981 meteorological data from Walnut Station, and SCAQMD's 1987 ambient vinyl chloride monitoring data from Station A, B, and MY (Table 19). Population estimates for each square-kilometer cell were determined from 1985 population census estimates. The 1,681 grid cells and associated population estimates were sorted from high to low by modeled vinyl chloride concentrations. Grid cell populations were then summed to determine the cumulative population exposed to a certain level of modeled vinyl chloride concentration. Table 20 shows the results of CARB's modeling. Using CARB's modeled vinyl chloride concentrations, and applying th present risk calculation, the individual excess lifetime cancer risk ranges from 7 in 100,000,000 for exposure to 0.01 ppb of vinyl chloride to 4 in 100,000 for exposure to 7 ppb of vinyl chloride (Table 21). R&S151965 -76- TABLE 19 (CARB) TABLE II-l SUMMARY STATISTICS FOR THE JANUARY 1987 THROUGH DECEMBER 1987 MONITORING DATA FOR VINYL CHLORIDE NEAR BMC LANDFILL (Concentrations reported In parts per billion (ppb)) Station 1 Station 2 Station 3 Number of samples Percent of Samples Below the LOD* Estimated Concentration for** Samples Below the LOD Estimated Meanb Concentration Maximum 24-Hour Concentration0 337 73 1.0 1.7 7 337 90 1.0 1.2 8 345 55 1.1 2.6 15 a - The SCAQMD's limit of detection (LOD) for vinyl chloride 1$ 2 ppb. b - Gleit's method was used to estimate the concentration of samples below ,, the LOO. c - California's Ambient Air Quality Standard for vinyl chloride is 10 ppb for a 24-hour averaging period. Source: California Air Resources Board, Tabl* II-l, "Technical Support Document, Fropoaad Identification of Vinyl Chlorida as a Toxic Air Contaminant, Draft Report, Executive Stannary and Part A," Stationary Sourca Division, May 1990, p. A-7. Stations 1, 2, and 3 ara Stations A. B, and MY respectively. TABLE 20 (CARB) Vinyl Chloride Concentration 0.01 o.os 0.1 1.0 2.0 3.0 4.0 5.0 5.0 7.0 TABLE II-B RANGE OF CUMULATIYE POPUUTIOH EXPOSED TO VIHYl CHLORIDE NEAR BKE Btnnr of Cumulative Population Finmefl iver*Bound Estimate* Upper-Bound. 0 2.026.000 - 2.154.000 732.000 - 1.970.000 374.000 - 1.431.000 17,000 0 0 - 131.000 54.000 28.000 0 20.000 0 14,000 0 7.000 0 2.500 a - The exposure estimate is eased on a vinyl chloride emission rate of C.75 micrograms meter'* sect* o - The exposure estimate is based on a vinyl chloride emission rate of 3.32 micrograms meter'* secT* Source California Air Resources Board, Tabla II-5, "Technical Support Document, Propoaod Identification of Vinyl Chloride as a Toxic Air Contaminant. Draft Report, Executive Sumnary and Fart A", Stationary Source Division, Hay 1990, p. A-ll, Modeled data is for an area approximately 25 miles-by-25 miles around the B.K.K. Landfill, West Covina. California. TABLE 21 INDIVIDUAL EXCESS LIFETIME CANCER RISK* CARB MODELING OF 19B7 AMBIENT VINYL CHLORIDE CONCENTRATIONS NEAR BKK LANDFILL. WEST COVINA. CA Modeled Vinyl Chloride Concentration ppb M*/m3 Cancer Risk .01 0.1 1.0 2.0 7.0 .03 0.3 2.6 3.1 17.9 6.3E-8 6.3E-7 5.6E-6 1.11-3 3.9E-S ft: Calculated by ECR - Cvc xYRxEFxRFxURx 1/LT where ECR m Excess lifetime cancer risk Cvc - Concentration in MS/m3 of vinyl chloride YR - Years of residence associated with exposure (70) EF - Exposure factor, l.a. percent of time at home (80Z) RF Retention factor, l.e. percent of measured concentration absorbed in the lungs (100X) UR - Unit risk value for vinyl chloride: 2.7 x 10" (Mg/m3)*3 , taken from Table 3.13, "Air Toxics Assessment Manual", California Air Pollution Control Officer's Association. October 1987, p. 3.3-28. Value current through June 1989. LT m Human individual lifetime in years (70) b: Modeled vinyl chloride concentrations in ppb are takan from Table II-5, "Technical Support Document, Proposed Identification of Vinyl Chloride As A Toxic Contaminant, Draft Report, Executive Summary and Fart A," CARB Stationary Source Division, May 1990. p*. A-l*. -79 99 CD o CD OS 2. Numerical Estimation - Population Excess Cancer Burden The population excess cancer burden is calculated by multiplying the individual excess lifetime cancer risk in an exposed area by the population in the exposed area. The individual excess lifetime cancer risks estimated in the risk characterization scenarios of the B.K.K. Landfill are: 1987 Ambient Vinyl Chloride Monitoring, Station MY 1.5 x 10"5 1982-1987 Ambient Vinyl Chloride Monitoring 1.8 x 10_s 1982 Expanded Monitoring Program, excluding benzene 5.2 x 10-5 1984 Extended Monitoring Program, excluding benzene 5.8 X 10-6 Modeling of 1987 Ambient Vinyl Chloride 6.5 x 10"8 to 3.9 x 10'5 In 1985, EPA estimated the population within a one-mile radius of the center of the B.K.K. Landfill to be approximately 40,000 persons (LPA, 1985). In actual fact, not all 40,000 persons are exposed to the levels of vinyl chloride suggested in these scenarios. Most residents are exposed to lower levels. CARB's Table 19 shows that in 1987 the proportions of samples below the detection limit of 2 ppb was 73 percent, 90 percent, and 55 percent for Stations A, B, and MY respectively. Based on the risk characterization scenarios, the most appropriate individual excess lifetime cancer risk to estimate population excess cancer burden is derived from monitored data at Station MY. Using the individual excess lifetime cancer risk of 1.5 x 10'5 associated with 1987 ambient vinyl chloride monitoring at Station MY, and the estimated -80- populati n within a one-mile radius of the B.K.K. Landfill, the estimated population excess cancer burden is 0.6. That is, in a population of 40,000 persons less than one additional case of cancer would be associated with exposure to vinyl chloride at 2.7 ppb for an entire 70-year period. Limitations and Uncertainties A risk number is an estimate of the risk of adverse health effects conditional on the methods and assumptions of the risk characterization, and the limitations and uncertainties of the data collection. CH2MH111 addressed the limitations and uncertainties of the data collection in its exposure characterization (CH2MH111, 1988). These included the following; only a few air monitoring data sets were judged to be appropriate for quantitative risk assessment based on a retrospective quality assurance review; 24-hour air samples were collected, providing data on average air emissions only; air monitoring data are primarily from residential stations in the south and southeast which represent nighttime ("worst-case"), air flow. detection limits for vinyl chloride and benzene have changed, limiting direct comparison of data over time; -81-  not; all analytes were measured in all media, and some media (soil, particulates) were rarely sampled; . demographics are based on the 1980 U. S. population census data and projections, although there has been considerable development around the B.K.K. Landfill. Limitations of this health risk assessment include the following: use of data from 1982 through 1987 only; use of different summary statistics (that is, geometric means, arithmetic means, medians, and annual averages); use of June 1989 toxicity values. Uncertainties inherent in this health risk assessment include; the assumptions stated at the beginning of the risk characterization; the choice of unit risk values. The Class I Hazardous Waste Management Unit stopped accepting hazardous waste by December 1984, and was capped and closed in March 1989. Mitigation measures stipulated in the SAM Work Plan may be expected to reduce vinyl chloride emissions to levels and frequences below those detected in 1987. Significance of the Risk Excess lifetime cancer risk is estimated in order to assess the potential impact of a particular exposure in addition to the relatively constant background level of cancer risk. An individual has approximately a one in three (3 x 10'1) risk of developing cancer during his or her lifetime. The ambient vinyl chloride monitoring data represent the most appropriate data to assess the excess cancer risk associated with the B.K.K. Landfill because vinyl chloride is not commonly detected in the Los Angeles air basin. Carcinogens such as benzene, perchloroethylene, and trichloroethylene are detected in ambient air both at the B.K.K. Landfill and in the Los Angeles basin. These compounds may present an additional cancer risk to people living near the B.K.K. Landfill but it is not possible with the present data to distinguish between exposure due to ambient levels and exposure due to the B.K.K. Landfill. Vinyl chloride is rarely detected in the ambient air, and therefore vinyl chloride more clearly represents the increased exposure associated with the B.K.K. Landfill. Based on the 1987 ambient vinyl chloride concentrations, and the methods and assumptions used in this health risk assessment, the individual excess lifetime cancer risk associated with exposure to the carcinogen detected in ait around the B.K.K. Landfill is estimated to be approximately 1 to 2 individuals in 100,000 persons. This assumes everyone is exposed to vinyl chloride at the 1987 concentrations for an entire 70*year lifetime. Most residents are exposed to lower levels of vinyl chloride and most -83- residents are not likely to stay at one place an entire lifetime. Mitigation measures stipulated in the SAM Work Plan may be expected to reduce vinyl chloride emissions from the B.K.K. Landfill. Currently, DHS and CARB are reevaluating the data on the carcinogenicity of vinyl chloride, in recent and past literature, for the purpose of identifying vinyl chloride as a toxic air contaminant, pursuant to the Health and Safety Code Section 39650 et seq. When this process is completed, a new unit risk value for vinyl chloride will be established. The new value is likely to be about 29 times greater than the value used in this health risk assessment. When this new value is adopted, OHS will prepare an addendum to this risk assessment, reflecting the changed unit risk value for vinyl chloride, updating toxicity values, and adding air monitoring data collected since 1987. -84- /.6VSVS'8tl REFERENCES 1. Bogen, K.T. and Smith, M.T. "Risk Assessment for Exposure to Ambient Air in the Vicinity of the BKK Landfill in West Covina, 1978-1985." Unpublished paper. April 1986. 2. California Air Resources Board. "Technical Support Document, Fropos d Identification of Vinyl Chloride as a Toxic Contaminant, Draft Report." Parts A and B. CARB, Stationary Source Division. Hay 1990. 3. California Department of Health Services. "BKK Reoccupancy and Relocation Criteria." Draft Memorandum From Epidemiological Studies Section, Preventive Medical Services Division, to Angelo Bellomo, Chief, Southern California Section, Toxic Substances Control Program. October 30, 1984. 4. California Air Pollution Control Officers Association. "Air Toxics Assessment Manual. Toxic Air Pollutant Source Assessment Manual for California Air Pollution Control Districts and Applicants for Air Pollution Control District Permits." October 1987. 5. California Department of Health Services-Toxic Substances Control Program, California Air Resources Board, and South Coast Air Quality Management District. "Ambient Air Monitoring And Health Risk Assessment for Suspect Human Carcinogens Around the BKK Landfill in West Covina." Unpublished paper. March 1983. 6. CH2MH111. "BKK Landfill Environmental Exposure Characterization Report, West Covina, California." August 15, 1988. Volume I - Text; Volume II - Plates 1-17; Appendices Volume 1 F-l to F-3 (groundwater data). Volume 2 F-4 (groundwater data). Volume 3 F-4 and F-5 (groundwater data), Volume 4 F-5 (groundwater data) and G*1 (surface water data), Volume 5 G-2 (surface water data),H-l and H-2 (air data), and I (soils data). 7. Crump, K.S. and Co. "Estimates of Carcinogenic Risk in the Vicinity of BKK Landfill." Unpublished paper. Ruston, Louisiana. March 1986. 8. Environmental Solutions, Inc. "BKK LandfillSite Assessment and Mitigation Work Plan. Book I, Subsurface: Site Characterization." March 15, 1988. 9. South Coast Air Quality Management District. "Vinyl Chloride in the South Coast Air Basin." May 1982. 10. South Coast AirQuality Management District. "The Magnitude of Ambient Air Toxics Impacts From Existing Sources in the South Coast Air Basin." 1987 Air Quality Management Plan Revision Working Paper No. 3. June 1987. R&S151974 -85- 11. Study Group on Risk Assessment Presentation. "Presentation of Risk Assessments of Carcinogens, Report of an Ad Hoc Study Group on Risk Assessment Presentation." American Industrial Health Council. Washington, D.C. July 1989. 12. U. S. Environmental Protection Agency. "BKK Update: Information about the BKK Landfill, West Covina, California." EPA Region 9. Issue No. 1, March 1985. 13. U. S. Environmental Protection Agency. "Superfund Public Health Evaluation Manual." EPA 540/1-86/060 (OSWER Directive 9285.4-1). October 1986. 14. U. S. Environmental Protection Agency. "Guidelines for Carcinogenic Risk Assessment." Federal Register. 51:33992 - 34003, 1986. 15. U. S. Environmental Protection Agency. "Integrated Risk Information System (IRIS)." Database access June 1989. 16. U. S. Environmental Protection Agency. "Risk Assessment Guidance for Superfund, Human Health Evaluation Manual Part A, Interim Final." EPA OSWER Directive 9285.701A. July 1989. 17. U. S. Environmental Protection Agency. "Health Effects Assessment Summary Tables, Third Quarter FY 1989." EPA OERR 9200.6-303-(89-3). July 1989. R&S151975 or APPENDIX A R&S151976 SUMMARY OF THE THREE PREVIOUS HEALTH RISK ASSESSMENTS OF THE B.K.K. LANDFILL, WEST COVINA, CALIFORNIA Three previous health risk assessments have been performed evaluating residential exposure to seven carcinogens detected in ambient air around the B.K.K. Landfill. Risk estimates varied due to different assumptions and methods of risk calculation, as described in the following paragraphs. Copies of the three risk assessments are provided as Appendices A, B, and C. The seven carcinogens evaluated were: vinyl chloride, benzene, trichloroethylene (TCE), 1,1-dichloroethylene (vinylidene chloride), perchloroethylene (PCE), 1,2-dichloroethane (ethylene dichloride), and trichloromethane (chloroform). 1. "Ambient Air Monitoring and Health Risk Assessment for Suspect Human Carcinogens Around the BKK Landfill in West Covina", Department of Health Services-Toxic Substances Control Program/California Air Resources Board/South Coast Air Quality Management District (DHS-TSCP/CARB/SCAQMD), March 1983. (Appendix B) During July to October 1982, DHS-TSCP, CARB, and SCAQMD conducted a 90-day study to monitor ambient air around the B.K.K. Landfill for nine volatile organic compounds in response to continued concerns from neighboring residents. Twenty-four hour ambient air samples were collected in Tedlar bags on Sunday through Thursday at six sample stations. Figure 7 of this report (and Figure I of Appendix A) shows the locations of the stations: Stations A and B were located in residential areas south of the landfill, reflecting nighttime air drainage patterns; Station D was located at the entrance to th landfill; Station E was located at the highest elevation within the landfill, reflecting daytime transport; Station F was initially located in a residential area on the northeast side and on August 26, 1982, it was moved to the northwest in response to odor complaints from that area. Station C was located in Pico Rivera, nine miles southwest (upwind) of the facility, to estimate background levels. Stations A, B, D, and E were within 400 to 1,000 feet of the waste disposal area while Station F was 2,500 and 6,000 feet from the facility. The data given for Station F are an equally weighted average of the two locations. Split samples were taken and analyzed by two laboratories, SCAQMD's laboratory and CARB's southern laboratory branch, (Haagen-Smit) . DHS considered the nine volatile organic compounds to be known or potential human carcinogens: vinyl chloride, benzene, perchloroethylene, trichloroethylene, 1,1-dichloroethylene, chloroform, 1,2-dichloroethane, chlorobenzene, and trans*l,2-dichloroethene. The report stated that chlorobenzene and trans-1,2-dichloroethene were not detected. The remaining seven chemicals were detected in concentrations near the analytical limit of detection. Elevated levels of the seven were found around the B.K.K, Landfill compared to the control community of Pico Rivera. Stations A, B, and D had consistently more elevated levels than Stations E and F. R&S151978 The risk assessment focused solely on the risk of cancer because the chemicals were detected in concentrations considered below their threshold for non-carcinogenic, toxic effects -- even at the highest concentrations detected. Excess cancer risks were derived by subtracting the average concentration of each substance at Station C from the average concentration of that substance at the B.K.K. Lanofill monitoring site. The exposure period was defined as the previous seven years, 1975 to 1982, since that time reflected the beginning of recorded waste deposits, the landfill expansion from 40 acres to 140 acres, and the increased residential construction along the southern border. The report did not identify slope factors or unit risk values used in the risk calculation. Individual excess lifetime (70-year) cancer risk was based on the following assumptions: no dilution in the measured concentrations at Stations A-Ft - exposure for 24 hrs/day, 365 days/year, for 7 years (1975-1982); 100 percent absorption in the lungs. The maximum individual excess lifetime cancer risk attributable to emissions from the B.K.K. Landfill for the previous 7 years was estimated to be approximately 5 per 100,000 (5 x 10"s) . The population living within a one-mile radius of the B.K.K. Landfill property line was estimated to be approximately 7,700 persons. This number was derived by dividing the county assessor's plot maps into quadrants corresponding to monitoring Stations A, B, D, and F, and estimating the population within each quadrant from the 1980 census data. The population excess cancer burden was calculated for the population within each quadrant using the mean concentration difference for the respective station, then summing the derived excess number of cancers. Ho additional cases of cancer were suggested. "Estimates of Carcinogenic Risk in the Vicinity of the BKK Landfill", K. S. Crump and Co., Inc., March 1986. (Appendix C) In March 1986, K. S. Crump, as a consultant to attorneys for the B.K.K. Landfill, performed a risk assessment on the seven carcinogens detected in the DHS-TSCP/CARB/SCAQMD 1983 report. Crump identified epidemiologic data that he used to derive a human potency estimate for benzene, and the animal toxicologic data that he used in the linearized multistage extrapolation model to derive human potency estimates for the six other compounds. Exposure concentrations were taken from two air monitoring programs: the SCAQMD 1981-1985 ambient vinyl chloride monitoring program of the B.K.K. Landfill, supplemented by a University of Southern California 1980 residential monitoring program around the B.K.K. Landfill. The following assumptions were used: average air concentrations, from 12 SCAQMD stations and stations; exposure for 24 hours per day, 365 days per year, for 8 (1978-1985). 4 USC years According to Crump's methods, the lowest maximum likelihood estimate of total risk from all seven carcinogens was 2.5 x 10~6 and the highest upper 95 percent confidence limit estimate of total risk was 11 x 10-6 (Table 11 of Appendix B). If typical year-round occupancy of a home were no more than 12 hours/day. Crump estimated the risk to range between 1.25 to 6 per million people exposed. 3. "Risk Assessment for Exposure to Ambient Air in the Vicinity of the BKK Landfill in West Covina, 1978-1985", K. T. Bogen and M. T. Smith, April 1986. (Appendix D) In April 1986, Bogen and Smith, as consultants to attorneys for the B.K.K. Landfill, performed a risk assessment on the seven carcinogens detected in the DHS-TSCP/CARB/SCAQHD 1983 report. Bogen and Smith identified relevant animal bioassay data and used a Monte Carlo Potency Analysis (MCPA) method to derive potency distributions for the seven carcinogens. The MCPA method uses the multistage model of cancer, but rather than a single upper-bound confidence value for potency, Monte Carlo simulation produced complete distributions for potency estimation error. The following assumptions were applied by Bogen and Smith to the data in the 1983 DHS-TSCP/CARB/SCAQMD report: 50 percent dilution in the measured concentrations at Stations A, B, D, and F due to dispersion in ambient air; exposure for 15 hours/day, 365 days/year, for 7 years (1978-1985); 50 percent absorption in the lungs, based on a study cited by Bogen and Smith. Potency distributions were generated for each compound and each monitoring station and, again using a Monte Carlo procedure, the - corresponding potencies were added to obtain a distribution of total increased risk from all seven compounds. From the latter distribution, Bogen and Smith selected the 50th percentile value of 2.2 x 10"6 as a "best" estimate of increased lifetime cancer risk for the average individual living near the B.K.K. Landfill for the seven-year period. The "best" estimate value is a risk value as likely as not to overestimate the true level of average increased individual risk. Assuming the population of 7,700 exposed individuals from the DHS-TSCP/CARB/SCAQMD 1983 report, Bogen and Smith calculated a population excess cancer burden of 0.01 cases. R&S151980 Report TABLE 22 SUMMARY OF THE THREE PREVIOUS HEALTH RISK ASSESSMENTS OF THE BKK LANDFILL, UEST COVINA, CA Assuapt ions Methods Excess Cencer Risk "Ambient Air Monitoring and Health Risk Assessment for Suspect Hunan Carcinogens Around the BKK Landfill in West Covina." DHS -T SCP/CARB/SCAQMD 1983 "Estimates of Carcinogenic Risk in the Vicinity of the BKK Landfill." K.S. Crump t Co. 1986 "Risk Assessment for Exposure to Ambient Air in the Vicinity of the BKK Landfill in West Covina, 1978-1965." Bogen t Smith 1986 - no dilution in 1982 measured concentrations at Stations A B C 0 E F - exposure for 24 hrs/day 365 days/yr, 7 yrs (1975-82) - 10GX absorption In the lungs - average air concentrations from 12 SCAQMD Stations and 4 USC Stations - exposure for 24 hrs/day 365 days/yr, 8 yrs (1978-85) - 5OX dilution in 1982 measured concentrations at Stations A B D t F - exposure for 15 hrs/day 365 days/yr, 7 yrs (1978-85) individual excess lifetime cancer risk and population excess cancer burden 5 x 10' siaximum likelihood and upper 95X confidence limit estimate Monte Carlo potency analysts method and Monte Carlo procedure; "best" estimate 2.5-11 x 10'6 2.2 x 10'6 - 50X absorption in the lungs a: All three health risk assessments evaluated residential exposure to concentrations of the following seven carcinogens: vinyl chloride, benzene, trichloroethylene, perchtoroethylene, 1,1-dichloroethylene, 1,2-diehtoroethane, and chloroform. IBGiSlS'SH APPENDIX B R&S151982 Ambient Air Monitoring And Health Risk Assessment for Susoect Human Carcinogens Around the BKK Landfill in West Covina By California Department of Health Services Toxic Substances Control Qlvlslon California Air Resources Board Haagen>Smit Laboratory Division and South Coast Air Quality Management District March, 1983 1l CONTENTS Summary and Conclusions Introduction Background Purpose Compounds of Interest Methodology Sampling Strategy Analytical Methods Results and Olscusslon Meteorology Chemical Oata Health Effect Assessment * Page Numbers 3 4 S 6 7-8 9 10 11 * 13 Tables 14-20 Figures 21 - 29 Appendices '{Available Upon Request) Appendix A Detailed Sampling Methods Appendix B Oetalled Analytical Methods Appendix C Quality Assurance/Quality Control Oata Appendix 0 Chemical Oata Appendix E Meteorology Oata R&S151985 SUMMARY AND CONCLUSIONS 1. The ambient air concentrations of nine volatile compounds were monitored at five residential locations surrounding the BKK Corporations`s hazardous waste landfill in the City of West Covina for a three month period (July 19 October 15. 1982). These concentrations were compared to a control monitor located nine miles from the landfill site in a residential /commercial area of Pico Rivera. Those monitored substances Include: chloroethene (vinyl chloitide), tetrachloroethene (Perc), trichloroethene (TCE), 1,1-dichloroethene (vinylidene chloride), 1,2di chloroethane (ethylene dichloride), benzene, chlorobenzene, trichloromethane (chloroform), and trans-1, 2-dlchloroethene. The California Department of Health Services considers all of.these substances potential human carcinogens. 2. There continues to be periodic exceedences of the State Ambient Air Standard for vinyl chloride of 0.01 ppm (10 ppb). The concentrations of vinyl chloride as well as the frequency of exceedences are significantly lower than during the same period in 1981. This may be the result of the mitigation measures taken at the landfill since June 1981. 3. Relative to the Pico Rivera control station, air monitoring In the residential community around the 8KK landfill shows elevated levels of chloroethene (vinyl chloride), as well as tetrachloroethene (Perc), trichloroethene (TCE), 1,1-dlchloroethene (vinylIdene chloride), 1,2dlehloroethane (ethylene dichloride), and benzene. Many of these compounds are found at detectable levels in other areas of the Los Angeles . air basin. There is some data available which suggests that Perc, TCE and benzene occur at-comparable levels in some areas of the L.A. air basin. 4. Since the stations around the site are not known to be near other sources of emissions of ..these compounds (dry cleaning establishments, plastics products manufacturers, metal finishing Industries, etc.), the data sug gest that the BKK site is a source of these compounds. The elevated levels of the chlorinated compounds In particular Indicate a need for mitigation measures such as expansion of the landfill gas gathering sys tem, upgraded maintenance programs, and changes in handling of wastes containing these compounds. 5. Further action Is also mandated by the continued, periodic exceedences of the State's Ambient Air Quality Standard for vinyl chloride of 0.01 ppm (10 ppb). 6. All of the substances, even at the highest observed concentrations, are 3 c believed to be present in concentrations well below their tr.resnold for toxic, non-carcinogemc action. 7 At the low level of exposure experienced by residents adjacent to the BKK landfill, it is not possible to accurately calculate excess cancer risks. However, worst-case estimates of the individual excess cancer risks (maximizing both the exposure period and the concentrations) suggests that those residents living immediately adjacent to the landfill, and wno are also subject to both down wind and air drainage emissions from the site, may have accumulated excess risks to date of 5/100,000. This risk exceeds the level at which the Department attempts to control excess risks (1/1 ,000,000). Assumptions built jnto these calculations lead the Department to believe that these numbers represent a maximum risk and tnat the acutual risk is lower. 8. Based on an estimate of exposed population within a one mile radius of the landfill site boundary, no additional cases of cancer are to be expected from exposure to date. 9. The Individual cancer risks are at a relatively low level, and do not constitute a public health emergency. 10. Monitoring should be continued to determine the effectiveness of tne remedial actions tak.-n, and to further define: 1) The specific on-site sources of emissions, 2) The diurnal variation of concentrations and, 3) The dilution of these concentrations with distance frum the landfill. 4 R&S1519B7 INTRODUCTION ( BACKGROUND In October, 1980, odor complaints from resioents in the neighborhood surround ing the BKK landfill in West Covina prompted the South Coast Air Quality Management District (SCAQHO) to monitor for odorous organic compounds in tne vicinity of the site. In May, 1981, vinyl chloride was detected in the samples from tnis monitoring. A subsequent air survey confirmed the existence of vinyl chloride at concentrations exceeding the California Air Resources Board (AR8) Ambient Air Quality Standard of 0.Q1 ppm (24-hour average). The SCAQMO announced its findings in June, 1981.. Because of these exceedences, the California Department of Health Services (OHS) imnedtately banned further disposal of wastes containing vinyl chloride at the BKK Landfill. An evaluation of the vinyl chloride data by the OHS Indicated that although the levels posed no Immediate health hazard to the surrounding population, they were of sufficient concern to warrant prompt efforts to reduce these emissions from the landfill. Also In May, 1981, an Interagency task force consisting of the SCAQMO, OHS, City of West Covina, Los Angeles County Health Department, State Solid Waste Management Board, and the California Regional Water Quality Control Board (Los Angeles Region) was formed to develop a program to reduce the odor emissions from the site. This task force implemented a series of actions to expand the landfill's gas recovery system, and to Improve the efficiency of the waste gas incineration system. As a result of these efforts, the frequency of ex ceedences of the vinyl chloride standard, and of odor complaints, decreased significantly through the first half of 1982. These data were presented at a public meeting In the City of West Covina on July l, 1982. -Continued citizen concerns regarding their exposure to volatile carcinogens from the site and the need to determine the overall effectiveness of the emission mitigation measures prompted a sub-group of the task force consisting of OHS, ARB, and SCAQMO to embark on an expanded monitoring program. PURPOSE This study has .three purposes: 1) To evaluate the effectiveness of the mitigation measures already taken, and to determine whether or not further measures are necessary to control emissions from the site, 2) To determine if other volatile carcinogens besides vinyl chloride, known to have been disposed at the site In the past, are also present in the connunity at levels that would represent a public health concern, and 3) To provide a more comprehen sive data base for assessment of the health risk posed by emissions of carcinogens from the 8KK landfill in West Covina. 5 (a COHPOUNUS SELECTED FOR MONITORING Previous sampling of the landfill gas by SCAQMO, ARB, Euteck, Inc., and the University of Southern California indicated the presence at significant con centrations of suspected or known human carcinogens other than vinyl cr..pride. As with vinyl chloride, the presence of these compounds can be associated with the prior disposal of hazardous wastes at the site. Nine volatile compounds identified by these organizations were selected for monitoring based on their concentrations, carcinogenic potential, and the analytical capabilities of laboratories involved. These compounds are listed in Table l, along with Information on their uses, waste sources, and concentration in the landfill gas. OHS considers all nine compounds to be known or suspect human carcinogens. 6 6861SVS18U ( methodology , SAMPLING STRATEGY A meteorological survey previously conducted at the 8KK landfill and adjacent residential areas indicated that the daytime predominant wind direction was from the southwest to the northeast. However, eddies were observed throughout the landfill, which Is located in rough terrain on the south' slopes of the San Jose Hills. Radlatlonal cooling results In nighttime air drainage on the north and south slopes of the landfill, with wind flow from the south on the north slopes and from the north on the south slopes. The data from the.meteorological survey were correlated with odor complaints from the residential areas to determine the location of sampling sites which would reflect the maximum exposure of residents to toxic and hazardous gases emitted from the landfill. Six sites were selected and Identified alpnabetieally from A to F (See figure 1). Two (E & F) reflected the daytime transport of contaminants, three (A, 8 and 0) the nighttime transport, and one (C) was a control site nine miles away from the landfll in Pico Rivera. Sites A and B were located In residential areas on the south side of the landfill and F in a residential area on the northeast side. Stations A and 8 were established by SCAQMQ In Hay, 1981 as part of Its vinyl chloride monitor-. Ing program. On August 2S, 1982, site F was relocated to a residential area Northwest of the landfill because of odor complaints from this area. Sampling at this site was continued until the end of the program. Site 0 was located at the entrance to the landfill on Azusa Avenue to sample emissions diverted by the recently constructed berms on the southerly boundary of the site. These berms were designed to contain emissions while creating mechanical mixing and dilution of the toxic compounds. Site E was located at the highest elevation within the landfill itself, about 300 yards from the flares. The control site C'"was located at the SCAQMD Pico Rivera air monitoring station. This site was selected to reflect contaminant concentrations in an area not Influenced by the 8XK Landfill. It was also selected because it is the closest monitoring station to the site where more routine data has been collected over a period of years. The data from this site was not intended to reflect ambient air concentrations of these toxic compounds in the Los Angles air basin. A study period of three months (July 19 - October 15, 1982) was selected to provide an adequate data base. This period covered the warmest part of the year for the West Covina area. Samples were collected five.days per week, Sunday through Thursday. This frequency allowed sampling on one day with no activity on-site (Sunday), anq on four days of normal landfill operations. On this schedule, samples were analyzed, during periods of normal laboratory operations with a minimum of storage prior to laboratory analysis. 7 ( Samples were collected In Tedlar Bags continuously over a 24-hour period. This period was cnosen over a shorter 12-hour or 4 hour period Because it was necessary to determine the total daily dose of these ccmoounos that one would receive. It is also the time basis for the ARB's amoient air quality standard for vinyl choride: Q.G1 ppm. Tedlar bags were selected over other samoling methods such as absorbent tubes because of the greater confidence that :r.e bag samples would provide an accurate picture of these compounds in the air. This sampling period and method allowed comparison of the data from this program with data collected by the SCAQMO from Hay, 1981 to June, 1982. It is also accepted methodology by the U.S. Environmental Protection Agency, ARB, and SCAQMO for determining compliance with the vinyl chloride standard. An average of two samples per day were split between the two laboratories, SCAQMO and CARS (Haagen-Smit) laboratory. Each laboratory withdrew a sub sample directly from the septum opening of the Tedlar bag. The effectiveness of Tedlar bags for sampling chlorobenzene was unknown at the Initiation of the study period. Charcoal tubes were consequently selected as the medium for collecting these samples. Availability of equipment and laboratory capacity limited sampling to two per day; one at the control sta tion C and one at Station A or B. Chlorobenzene sampling was Initiated about midway through the study period, and analysis was performed by the OHS Air and Industrial Hygiene laboratory In Berkeley. ANALYTICAL HETHOOS Chloroethene (vinyl chloride) and benzene were analyzed using a gas chromatograph (GC) equipped with a flame ionization detector (FIO). Other chlorinated compounds, 1,1-dlchloroethene, trans-I.2-d1ch1oroethene, l,2-dlchloroethane, trlchloromethane (chloroform), trichloroethene (TCE) and tetrachloroethene (Perc) were analyzed usng a GC equipped with an electron capture detector (ECO). All compounds were quantified wth an electronic integrator. 3B*] C/D 2 8 <0 CO c RESULTS AND DISCUSSION METEOROLOGY Comparison of meteorological conditions during the three-month sampling period with the same period in previous years was necessary in order to determine whether the sampling results were influenced unduly by some abnormal weather condition. Since amoient temperature differentials are responsible for diffu sion and wind flow, and temperatures have been recorded by the National Weather Service In the San Gabriel Valley for the past twenty years, this was selected as one of the meteorological variables to examine, winds at the BKK site also determine the local transport of the contaminants. Therefore, the winds at Site A (because of Its exposure to the landfill) were compared for this three-month sampling period to those recorded In 1981. The temperature study Indicated that there was no significant difference between the average temperatures recorded during this three-month period and the 20-year average for the same three-month period. Frequency distributions for wind direction and speed were computed for the same three months in 1981 and 1982. Those directions which would impact Site A from the landfill were suonarlzed. No significant difference was exhibited between the frequencies for 1981 and 1982. AMBIENT AIR RESULTS Table II summarizes all of the data collected during the study period. Chiorobenzene and trans-l,2-d1chloroethene were not detected at any of the sampling stations during the study period, and are therefore not listed. The detection limits for each compound are shown In Table III. Statistical analysis of the split sample results revealed that the data from the two laboratories are not well correlated. The differences between the two laboratories was not unexpected, since the concentrations measured In this, survey were close to the limit of detection of the analytical methods. Therefore the mean concentration for each compound was calculated separately for each laboratory and station. The first number of each pair merely repre sents the lower of the two means from the laboratories, and the second numoer Is the higher mean value. Values reported as less than the limit of detection were set equal to the detection limit for purposes of calculating the mean concentrations. This treatment of the data allowed a conservative or worst case estimate of exposure for these compounds. It is recognized that In reality, these values can range anywhere from zero to the limit of detection. The ratio of the mean ambient air concentrations at stations A-F (those sta tion adjacent to the landfill) to the concentrations at the control station are shown in Table IV. These ratios were calculated separately for data from each laboratory. Figures [I through VIII show the ranges and means for each compound in a formatwhich allows the absolute concentration ranges to be plotted for each compoundstation, and laboratory during the study period. 9 DISCUSSION It Is apparent from Table IV that the mean concentrations at Stations A, 8, and and D are consistently higher than those at the control station for all compounds except chloroform. At Station , only TCE and ethylene dichloride appear consistently to exceed the control station value. Satation F con centrations exceed control station averages for Perc, TCE and vinyiidene chloride. These trends are also illustrated by Figures II through VIII. It should be noted that such large ranges In concentration are not a reflection of the impercision of the sampling and analytical methods, but are indicative of the wide daily fluctuations of concentrations in the air near the monitor ing stations. It should also be noted that the data from station F are actually an equally weighted composite from two locations. F^ and F^. These observations suggest that the BKX landfill may be a significant source of emissions of these compounds into the cofliminity. The levels of all compounds detected were consistently higher at stations A. B. and 0 than at Stations E and F* Since stations A. B. and 0 are located In areas where nightlme air drainage from the landfill is know to occur, it is likely that these elevated concentrations can be attributed to this phenomenon. The low levels at stations and F, which are located In areas not subject to the same flow patterns, further emphasize the importance of nightlme air drainage as the primary mode by which landfill emissions Impact the comnunity. This type of air movement does not allow as much dispersion as that which occurs in the daylight hours. 10 R&S151993 DISCUSSION OF HEALTH EFFECTS Introduction What are the expected health effects from exoosure to these substances at the concentrations observed in the area directly adjacent to the BKK lanofi117 For tnose suostances that can give non-carcinogenic acute and chronic toxic effects, such as liver, kidney or nerve damage, for low concentrations there is good evidence for a biological threshold, or a "no observed effect level". This means that concentrations below this threshold do not cause adverse health effects. All of the substances, even at the highest observed con centrations, are believed to be present In concentrations well below their threshold for toxtc, non-carcinogenic action. This gives a safety margin of from lOO-to-lOOQ fold In the concentrations before these substances even approach levels which could cause adverse health effects. It Is for this reason that this report concentrates solely on the risk of cancer. Carcinogenic Risk Assessment The chance of getting cancer Is calculated using risk assessment techniques. Risk assessment Is a science that predicts the probability or likelihood of an event occurring. It attempts to estimate the chances of cancer occurlng In a specified population, from a specified dose of a substance In a given tine period. Several facets go Into risk assessment: the carcinogenic potency of the substance .calculation of dosage from-exposure data and the number of people exposed (population at risk) and their Individual dosages. In order to evaluate the health Impact of those emissions due to the SICK site, use was made of the simple difference of the concentrations, l.e., the average concentration of each substance In the Pico Rivera Station was subtracted from the average concentration of that substance in the residential monitoring site. Thus, the derived risks are considered excess risks, or risks in addi tion to those typically Incurred away from the influence of the BKK landfill site. -- The stations selected for monitoring were those that in the past gave very high concentrations, suggesting that they are in the path of a drainage channel. In the absence of Information on the length, width and depth of the drainage areas, the dilution with distance (both lateral and down-nill), the concentrations of the initial drainages and the fraction of material that is carried by drainage and wind dispersions, it Is not possible to accurately estimate either exposures or the population at risk. However, It Is possible to estimate the upper limit or bound to this risk using a number of conserva tive assumptions. Some of the major assumptions are shown in Table V. The lifetime Incremental, worst-case estimated risk for residents adjacent to the BKK site, is based on the maximum possible period of exposure (24 hours/day, 7 days/week and S2 weeks/year). The exposures were projected from the observed 3-month monitoring period (August-October) for a maximum possible 11 R&S151994 t exposure period of seven years. Vinyl chloride is the only compound that air monitoring data is available for preceeding tne current monitoring perioa. In order to adjust the data for both seasonal variations and to correct for tne increased control measures that had been installed at the BKK site, the six other compounds were increased in proportion to their ratio to vinyl chloride for the prior monitoring periods. These calculations suggest that the maximum possible excess risk, is ap proximately 5 per hundred thousand (5/100This is the maximum increased lifetime risk of contracting cancer for those residents who have been subject to the emissions from the BKK landfill site for the past seven years. Thus, we can say with some certainty that the risk of getting cancer, attributable to exposure from emissions from the BKK lanofll is no greater than tms; wmle in fact, tne true excess risk of cancer is orooaoly lower, ~~ Population Comparisons The maximum individual excess risk can be better understood as applied to the exposed population. The accumulated individual excess risk multiplied by the population at risk (the number of people exposed to these concentrations) defines the maximum number of excess cancers expected during the lifetime of the exposed population. This results In an estimation of the additional cases of cancer expected during the lifetime of the exposed population due to the emissions from the BKK landfill site. The total population, at distances of up to one milefroo the BKK property line, were considered to be at risk (a total of approxmately 7700 people). This population was derived by dividing the assessor's plot maps into quad rants, corresponding to Monitoring Stations: A, B, 0, and F. The population within each quadrant was estimated using the latest census data of 1980. The exposure of tne population within each quadrant was assumed equal to that measured at the respective monitoring station. The total population within each quadrant was multiplied by the mean concentration difference for its. respective monitoring station, and the derived excess number of cancers was sunned. These calculations suggest that there should be no additional cases of cancer attributable to exposure from emissions from tne aKK Ianonll ounno tne lifetime of the population from exposure to date. The Department of Health Services has made a conscientious attempt to calcu late the worst-case estimate of risk. In those cases where there are insufficient data, the most conservative assumptions were used. As further information becomes available, such as, drainage patterns and dispersion rates, this additional data will be incorporated into the risk calculations. Although a small possibility exists that further information might increase the risk estimate, to the best of our knowledge, this new Information snould lower our worst-case risk estimates and provide a more accurate and realistic indication of risk. 12 c It is important that the provided risk estimates NOT be considered as static or "as engraved in stone." They are expected to change as further information become available. These revisions will be made to better refine the risk and not to obscure the true imoact. Such refinements wil be communicated to tne residents of West Covina as they become available. Several critical points should be kept In mind: 1. Since the biological mechanism of cancer is not known, mathematical models can only provide a best scientific "guess" of the dose* response relations at dosages much less than those employed in the bioassays. However, it is believed that at very low dosages, the shape of tne dose-response curve is concave upward. Thus, a linear model wilt provide the upper-limit for the risk for the experimental observations (see Figure IX). 2. The use of the upper-confidence values for the experimental results, then provides an added margin ef safety to Insure that the upperrisk level fs also based on the maximum possible number of cancers that statistically could occur from the experimental studies (see Figure X). 3. It Is not possible to calculate the actual risks at these low concentrations. Thus, it is very important that people understand that the presented risk numbers only represent the worst possible risk. It is expected that the true risks are lower than these .. numbers 4. These worst-case estimates of risk suggest that there should be no additional cases of cancer due to exposure to the emissions from the 8KK landfill. The Department of Health Services does NOT recommend any special medical precautions or treatment for those residents adjacent to the landfill site. 13 B&S151996 TABLE I COMPOUNDS SELECTED FOR HAHITORIKS COMPOUND (SVNONVH) I USES AND PROBABLE WASTE SOURCES .. Chloroethene (Vinyl Chloride) ^ 1,1 - Olchloroethene (Vlnyltdene Chloride) Trans-I,2-Dlchloroethene (Acetylene Dlchlorlde) Trichloroethene (TCE) Tetrachloroethene (Perc) /.eetsvsw Manufacture of PVC end other co-polymers; organic synthesis; adhesives for plastics; refregerant; manufacture of vinyl chloride also a significant waste source. Copolymerized with vinyl chloride to manufacture types of seran; adhesives for synthetic fibers. General solvent for organic materials, dye extraction, perfumes, lacquers, thermo-plastics, organic synthesis. Metal degreasing, extraction solvent for oils, fats, waxes; solvent dyeing; dry cleaning; refrigerant and heat exchange fluid; organic synthesis; fumigant; cleaning and drying electronic parts. Dry cleaning solvent; vapor-deoreaslng solvent; drying agent for aietals; heat exchange medium; manufacture of fluoro carbons. CONCENTRATION RANGE IN . LANDFILL GAS (ppm) 63 - 12000* N.O. - 1200b N.D. - BQQb N.O. - 1000b N.D. - 1500b TABLE 1 (CONTINUED) COMPOUND (SYNONYM) 1,2-Oichloroethane (Ethylene O(chlortde) t Trlchioromethane (Chloroform) Benzene 0 Chlorobenzene USES AND PROBABLE WASTE SOURCES Manufacture of vinyl chloride; organic synthesis; ant('knock agent In gasoline; paint, varnish, and finish removers; metal degreasing; soaps and scouring icompounds; .wetting and penetrating agent; ore flotation. Manufacture of fluorocarbon refrigerants and propellants; dyes 1 drugs; general solvent; fumigant; Insecticides. Manufacture of styrene, phenol, synthetic detergents, cyclohexane for nylon, aniline DDT, various other insecticides, funtgants; solvent; paint remover; rubber cement; anti-knock agent In gasoline. Manufacture of chloronitrobenzene, DOT, aniline; Intermediate and solvent for organic synthesis. CONCENTRATION RANGE IN LANDFILL GAS (ppm) N.D. - 5000b r 5. IC 0.038 (Ambient a1r)d 10 - 2000b N.D. - 5D0b /"V R&S 151998 Footnotes: a. Analytical Research Laboratories, Inc. "Report for BKK/Stauffer Chemical." June 17, 1981. b. Cutectc, Inc. "BKK Landfill Odor Study Final Report." Prepared for City of Vest covina. February 27, 1981. c. South Coast Air Quality Management District. "Report on Vinyl Chloride Emissions from a Class I Landfill Operation." Source lest Report C-81-96 A U. June 10, 1901*. d. University of Southern California. "Investigation of Odorous and Volatile Compounds for (IKK Class I Landfill Site in the City of Host Covina." Prepared for BKK Corporation. July* I1 TABLE II Chloroethene (Vinyl Chloride Tetrachloroethene (Perc) Sumnary of Ambient Air Oat** (ppb) A 7.1-7.3 ' B 4.5-5.5 Station C0 2-3 3.8-4,1 2.1-3.7 1.6-2.9 I.4-2.4 2*3-3.0 Trlchloroethene (ICE) 0.8-1.0 1,1-Dtchloroethene 1.1-1.3 (Vtnylidene Chloride) 1,2-Oichloroethane 1.3-3.0 (Ethylene Bichloride) Trlchloromethane (Chloroform) 0.3-0.5 0.8-1.8 0.7-1.0 0.6-2.8 0.2-0.3 1.6-1.7 0.1-0.3 0.7-0.6 HP 0.4-0.7 0.8-2.8 0.3-0.6 0.2-0.6 0.6-1.0 Benzene** 4.8 4.6 3.6 4.6 E 2.0-3 1.5-2.1 0.6-0.8 0.1-0.4 0.7-0.9 0.2 3.0 F 2-3 I.5-3.4 0.8-1.2 0.3-0.4 0.4-1.1 0.2 3.0 a. Each pair of values represents the means of the two laboratory data sets calculated for the entire study period. On those days when a compound was not detected, its concentra tion was assumed to be equal to the Halt of detection. b. One set of data used. All of the second set were below the Halt of detection. 666lStSlSy TABLE III c Detection Limits for Compounds Compound Chlorethene (Vinyl Chloride) * Tetrachloroethene (Perc) Trlchlorethene (TCE) 1,1-Oichloroethene (VinylIdene Chloride) 1.2-01chioroethane (Ethylene Qlchlorlde) Trlchloromethane (Chloroform) Trans-1,2-Dichloroethene Chlorobenzene Benzene Range of Oetectability (ppb) 2*3 0.1-0.2 0.1*0.2 0.1-0.3 0.2*0.4 0.02*0.1 1-3 104 2*20 a. Sampling by charcoal tube and analysis by one laboratory. R&S 152000 17 TABLE IV Ratio of Ambient Air Concentrations of Station A-F to Control Station Station Ca , Chloroethene (Vinyl Chloride) A Li-3.6 6 1.8-2.3 Station C0 1.0 1.4-1.9 ' 1.0 F 1.0 Tetrachloroethene (Percj l.S 1.2 1.0 1.2-1.6 0.9-1.1 1.4-2.1 TrIchloroethene (ICE) 2.9-3.9 3.0-7.2 1.0 .3-6.6 2.1-3.0 2.8-5.0 1,1-Dichloroethene 3.6-11 (Vtnylldene Chloride) 2.4-9.3 1.0 2.7-6.5 1.0-1.3 1.5-3.0 1,2-Dlchloroethane 3.3-4.5 (Ethylene Dlchlorfde) 1*9-4.3 1.0 1.9-4.3 1.3-1.7 1.0-1.7 Trlchloromethane (Chlorform) 0.4-2.7 1.0-1.4 1.0 1.7-3.1 0.4-1.1 0.4-1.0 Benzene*1 1.4 1.3 1.0 1.3 0.8 0.6 a. Ratios are calculated for each laboratory separately and expressed as a range. b. One laboratory data set available. vocft^ sl?a t( Table V Conservative Assumptions used by the California Department of Health Services to Estimate Cancer Risks from BKK. Emissions Animal Sioassav Studies 1. Use the most sensitive site, sex and animal species. 2. Use the upper 95.7t confidence value for the experimental data. 3. Assume all tumors (benign and malignant) are indicators of car* clnogenlc risk. 4. Use linear extrapolation for determining the risks at low dosages. Individual Risk Estimates 1. Use the measured concentration for each station as the human exposure, with no allowance for dilution with distance (downwind or laterial). 2. Assume an exposure for a full 24 hours/day, 7 days/week, and 52 weeks/year (with no allowance for leaving residence or air con ditioning In residence). 3. Assume. lOOt absorption for human exposure. 4. Selection of monitoring stations in drainage pathways. PoDulation at Risk 1. Assume maximum housing tract population at time of Issuance of permit to occupy. 2. Assume exposure from measured value at each monitoring Station with no allowance for dilution with distance (down-wind or laterial). 39 R&S152002 ( 3. No allowance for population being outside patterns. expected drainage R&S 152003 20 Flguro II 32 16 J3 cl - CL c ce o r-f -P 0 L P C4 QJ 0 C 0 CJ 2 i4 > 1 A Range and Mean for CHLOROETHENE (VINYL CHLORIDE) R&S152005 $ - Mean for .* Laboratory 1 4 - Mean for Laboratory 2 '> i > A <> 4 0 * 6 4 N (1 ti1 BcD Monitorial Stations 1 --____________I---------------------- E* F FigurQ III Range and Mean for TRICHLOROETHYLENE (TCE) 4 R&S 152006 A CL CL C oncentration in Monitordfcc| Stations C o n ce n tra tio n in ppb Figure IV 25.6 12. B 0.4 3.2 1.8 0.8 0.4 0.2 0.1 A Range and Mean for TETRACHLOROETHENE CPERC) R&S152007 * - Mean for Laboratory 1 A -- Mean for Laboratory 2 BD Monito^ng Stations Flguro V 12.8 8.4 - M CL, Q. 3.2 C *H n 1.8 o H -P 0 L -P 0.8 n QJ oc o 0.4 u 0.2 0.1 R anqe anad Mmean for 1, 2-DICHL0R0ETHANE(ETHYENE DICHLORIDE) R&S152008 * - Mean for Laboratory 1 A. - Mean for Laboratory 2 <> in C\J 0 B Monitoi^ppcj Stations Figure VI 4 Range and Mean for 1,1-DICHL0R0ETHENE(VINYLIDENE CHLORIDE) R&S 152009 JQ CL CL to CM C oncentration in Momtot^-icj Stat ions Figure VII 10.00 Range and Mean for TRICHLOROMETHANE(CHLOROFORM) 4 R&S 152010 C oncentration in ppb 1.00 0.10 - & 0.01 CD Monitoij^ncj Stations Figure VIII 8- * - <1 * Range and Mean for BENZENE R&S152011 - 6 * Mean f on . Laboratory 1 j3l - Mean for Laboratory 2 ir . i . < <t < ! - ( \ 1 lI t _ _ _ _ _ !_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ !- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - hB CDEF Monit^^ng Stations FIGURE IX R&S152012 FIGURE X t RISK * 29 APPENDIX C c ESTIMATES OF CARCINOGENIC RISK IN THE VICINITY OF THE BKK LANDFILL K S CRUMP and Co., Inc. 1201 Gaines Street Ruston, La. 71270 March 1, 1986 Introduction This document presents estimates of carcinogenic risk from seven volatile organic chemicals detected in the air around the BKK landfill in West Covina, California. These estimates were derived from epidemiologic and toxicologic data on these chemicals and air monitoring data from the site. The multistage mod 1 of cancer (Crump, 1985) was applied to animal data. This model is the model generally used by regulatory agencies, including the EPA, to obtain conservative upper limits to cancer risk. F r the one chemical in which human data were utilized (benzene), a linear 0 dose response model used to estimate benzene risk for OSHA regulations (CrtXmp and Allen, 1984) was utilized. Description of health effect data used For each chemical of interest we chose the most appropriate data sets available for making quantitative risk estimates. Animal bioassay data were used for all chemicals except benzene. Whenever inhalation studies were available, these were chosen over studies applying other routes of exposure. For the one ch raical for which where no inhalation data were available (chloroform), drinking water exposure was judged to be more appropriate than gavage due to the fact that gavage is more stressful to the R&S152016 R&S152017 ( animals. Data sets that provided positive results were used in favor of negative data except in cases where no positive data were available. From the positive data sets, risk was estimated from the data set which gave the largest risk (largest qi*, 95% upper limit on the linear term in the multistage model). In cases for which only negative data were available, the data set to model was decided on a case-by-case basis. Tetrachloroethylene: The tetrachloroethylene data sets chosen for analysis were from a study conducted by the National Toxicology Program (1985). The study utilized F344/N rats and B6C3Fi mice of both sexes with 49 or 50 animals/group. The animals were exposed to tetrachloroethylene by inhalation for 6 hours/day, 5 days/week, for 103 weeks. Mice were exposed to 0, 100, or 200 ppm tetra chloroethylene, while rats were exposed to 0, 200, or 400 ppm. The data set' that gave the highest risk, and was therefore chosen to be modeled, was male mice with hepatocellular carcinoma (Table 1). The incidence of this tumor type in the male mice was 7/49 (number of mice with tumor/number examined for the response) in the control group, 25/49 in the low-dose group, and 26/50 in_ the high-dose group. Trichloroethylene: Data sets from two trichloroethylene studies were considered for analysis. A study by Henschler et al. (1980) was conducted using male and female mice (strain Han:NMRI) and rats (strain Han:WIST). The animals were divided into groups of 30 an imals/sex/dose level. Exposure to trichloroethylene was carried out 5 days/week, 6 hours/day, for 78 weeks, with a total I 3 experimental length of up to 128 weeks. Both rats and mice were exposed to 0, 100, or 500 ppm trichloroethylene. In an inhalation study by Fukuda et aJ. (1983), groups of 49 or 50 female ICR mice and female SO rats were exposed to trichlo roethylene 7 hours/day, 5 days/week for 104 weeks. All animals were exposed to 0, 50, 150, or 450 ppm trichloroethylene. The data set from these studies that gave the highest risk, and was therefore used to estimate risk, was female mice - total malignant tumor bearing animals from Henschler at aJ. (1980) (Table 2). The incidence of malignant tumors in the female mice was 13/29 (number of animals with tumor/number of animals examined for the response) in the control group, and 22/30 in the 1 w-dose group, and 22/28 in the high-dose group. 1,2-Dichioroethane: The 1,2-dichloroethane data set chos n'for analysis was selected from a study by Maltoni at al. (1980). The animals used in this study consisted of male and female Swiss mice apd Sprague-Dawley rats. Groups of 90 animals/sex (mice control groups were larger: male - 115; female - 134) were exposed to 1,2dichloroethane in concentrations of 0, 5, 10, 50, or 250-150 ppm (the 250 ppm concentration was reduced to 150 ppm after tw we ks) for 78 weeks, with total experimental length of 119 weeks for mic and 148 weeks for rats. Exposures were carried out 5 days/week for 7 hours/day. The authors concluded that under the conditions of this study 1,2--dichloroethane did not show carcinogenic effects. Although data from female rats with non-malIgnant mammary tumors provided the highest risk, these data exhibited a non- R&S152018 R&S152019 4 monotone dose response and did not fit the multistage model. Since this was a negative study, the result for this data set was likely to be spurious; therefore the data set with the next highest risk was chosen for estimating risk. This data set was male rats - total tumor bearing animals (Table 3). The incidence of tumors in the male rats was 8/90 (number of animals with a tumor/number of animals examined) in the control group, 11/90 in the 5 ppm group, 5/90 in the 10 ppm group, 10/90 in the 50 ppm group, and 11/90 in the 250-150 ppm group. Vinvlidene chloride: Data sets from three vinylidene chloride . studies were considered for analysis. In a study by Viola and Caputo (1977), male and female Wistar rats were exposed t vinylidene chloride at 0 or 200 ppm for 20 weeks, then 0 or 100 ppm for 31 weeks. The rats were then observed for an additional 53 weeks. The exposures were carried out 5 days/week for 4 hours/day. Another study by tee et al. (1977) involved the exposure of male and female CD-I mice to 0 or 55 ppm vinylidene chloride. The animals were divided into groups of 36 mice/sex/dose level and exposed to the vinylidene chloride 5 days/week, 4 hours/day for 52 weeks, with no additional observation period. Maltoni et al. (1982) conducted a study in which male and female Sprague-Dawley rats were exposed to 0, 10, 25, 50, 100, or 150 ppm vinylidene chloride for 52 weeks, with an additional observation period of up to 78 weeks. The animals were divided into groups of 30 or 60 animals with 100 controls/sex. Exposures were carried out 5 days/week for 4 hours/day. cc 5 All of the vinylidene chloride data sets considered were negative. Since the studies by Viola and Caput'o (1977) and Lee et al. (1977) only involved one treatment group and did not observe the animals for their full life spans, we chose to estimate risk % from Maltoni et al. (1982). The data set chosen from this study was male rats with brain tumors (Tahle 4). The incidence of tumors in the male rats was 3/100 (number of animals with tumor/number of animals examined) in the control group, and 1/30 in the 10 ppm group, 0/30 in the 25 ppm group, 2/30 in the 50 ppm group, 0/30 in the 100 ppm group, and 0/60 in the 150 ppm group. Vinyl chloride; The vinyl chloride data set that was chosen for analysis was from studies by Maltoni et al. (1981). In this study, Sprague-Dawley rats were exposed to vinyl chloride 4 hours/day, 5 days/week for 52 weeks, with an additional observa tion period which lasted until the animals' natural deaths. Exposure levels ranged from 1 to 10000 ppm. The data smt that was used for risk assessment was rats with liver angiosarcoma (Table 5). This data came from several studies by Maltoni that employed similar protocols (Crump, 1982). The incidence of this tumor type, along with the respective treatment group, was as follows: 0/461 - control group (number of animals with tumor/number animals examined - treatment group); 0/118 -1 ppm; 0/119 - 5 ppm; 1/119 - 10 ppm; 5/120 - 25 ppm; 15/354 - 50 ppm; 1/120 - 100 ppm; 6/119 - 150 ppm; 12/120 - 200 ppm; 3/59 250 ppm; 6/60 - 500 ppm; 13/60 - 2500 ppm; 13/59 - 6000 ppm. The highest dose group showed a lower response than that obtained at lower doses. This decreased effect could not be explained by the R&S152020 ( (f R&S 152021 model and was therefore omitted (Crump, 1982). 6 Gehring et al. (1978) showed that the amount of vinyl chloride metabolized is not a linear function of exposure dose, but follows Michalis-Menton kinetics with metabolized dose being saturated at high doses. This information was used in*this analysis; exposure dose was converted to the metabolized doses shown in Table 5, the model was fit using metabolized dose, and the results were then translated back into exposure dose (Crump, 1982). Chloroform! No inhalation data was available for chloroform. Therefore, the data sets that were chosen for analysis were derived from a recent drinking water study by Jorgenson at ml (1985). In this study, male Osborne-Mendel rats and female B6C3Fi mice were given drinking water containing 0, 200, 400, 900, or 1800 mg chloroform. Water was available to the animals ad libitum for the duration of the study (104 weeks). Two control groups were employed in this study, the difference being that the water intake was restricted for one of the groups. Since the tumor incidence was not significantly different between the two control groups, we combined them as one group. The data set which gave the highest risk, and was therefore chosen to be modeled, was male rats - all kidney tumors (Table 6). The incidence of this tumor type in the male rats was 6/531 (number animals with tumor/number animals examined) in the control group, 6/313 in the 200 mg/1 group, 7/148 in the 400 mg/1 group, 3/48 in the 900 mg/1 group, and 7/50 in the 1800 rag/1 gr up. Benzene: Risk estimates for benzene were derived from a risk assessment based upon human epidemiological data that was c 7 performed by Crump and Allen (1984) for OSHA. Crump and Allen estimated risk for 40 years of occupational exposure to one ppm benzene using six different models. The highest estimate was 9.5 per thousand and was obtained using a relative risk model with cumulative dose. A more middle-of-the-road estimate was that f 1.5 per thousand, which was obtained using an absolute risk model and weighted cumulative exposure. Therefore two estimates f the potency of benzene for causing leukemia under continuous lifetime exposure are used in this document: (1.5/1000)(365 days/240 days)(70 years/40 years)(2) = 0.0053 [ppm*1 and (9.5/1000)(365 days/240 days)(70 years/40 years)(2) = 0.033 [ppm-1] Upper 95% statistical confidence limits for these potency estimates are also used. The value of 240 days is the number of work days per year assumed in the occupational cohorts from which the risk estimates were derived. The factor of 2 reflects an estimate that the total amount of air breathed by humans in a day is roughly twice what is breathed by workers during work hours. Methodology for estimating human risk from animal data The multistage model (Crump, 1985) is used in this analysis for low dose extrapolation with animal data. The multistage model is given by R&S 152022 R&S152023 c 8 P(d) = l - exp(-qo - qid - ... - q*d"), * qt >. 0, i = 0,l,,..,k, where d is dose, P(d) is the lifetime probability of cancer at dose d and k, qo,...,qn are parameters. In practice, k is set equal to the number of dose groups less on* The measure of risk used is extra risk above background, defined as [P(d) - P(0)]/[1 - P(0)]. Extra risk may be interpreted as the probability of the occurrence of a cancer at a dose d, given that no cancer would have occurred in the absence of a dose. Under the multistage model, the 95% upper limit on extra risk for a dose of d may be adequately approximated by q!*d, where qi" is the 95% upper limit on the coefficient qi . _The multistage model is implemented using the computer program GL0BAL85 developed by Dr. R. B. Howe for K S CRUMP and Co. Parameters of the multistage model are estimated by the method of maximum likelihood (Crump and Howe, 1985) and a .. likelihood approach is used to estimate qia. The dose levels used for input into the multistage model are shown in Tables 1-6. These doses were the experimental doses reported in the study except for vinyl chloride, in which case the experimental doses were converted to metabolized doses as discussed earlier. Potency estimates (qi*s) used to obtain upper limits to human risk were made under three assumptions: that human c 9 and animal risk are equal when dose is measured in 1) ppm in air; 2) mg/kg body weight/day: and 3) mg/m2 surface area/day. To esti mate human potencies under these assumptions, potency estimates based upon the experimental doses were converted to equivalent units of [ppm"l] assuming the animals had been exposed continu ously throughout their life. For example, if animals were exposed by inhalation 6 hours per day, 5 days per week, the potency estimate in [ppm]*1 was multiplied by (24 hours/6 hours) and by (7 days/5 days). If the duration of exposure, 0, was less than (0.8)(104 weeks) = 83.2 weeks, the potency estimate was als multiplied by 83.2/D, which averages exposure over the first 80% of the animal's natural lifespan. This adjustment corrects for less than lifetime exposure in an experiment and is based upon the supposition that exposure during the last 20% of an animal's .life span is unlikely to affect its chances of getting a tumor. The value of 104 weeks that is used to represent typical mice and rat lirfe spans is the current duration of NTP bioassays. These potency estimates in ppm-1 units were then converted, using animal parameters, (body weights, breathing rates, etc.) to units commensurate with the dose units for which human and animal risks were assumed to equate ([mg/kg/day]* 1 , (mg/ra2/day] 1 or [ppm]-1 - no conversion being required* in this latter case). These animal potency estimates were assumed to represent human potency estimates and were then converted using human parameters (body weights, etc.) to the desired units ([ppm]*1 and [mg/kg/day]). Standard parameters for mice, rats, and humans used in these dose conversions are displayed in Table 7. Study- R&S152024 c 10 specific animal parameters were used in place of these standard values whenever available. Table 8 displays the human potency estimates so calculated, along with similar estimates derived by EPA. The chief differ ences between the EPA methodology and ours is that EPA did not give priority to inhalation studies (their goal was to derive general potency values and not to estimate risk from a particular route of exposure) and they converted risk from animals to humans on a mg/m2/day basis. Data on chemicals for which both human and animal data exist suggest that animal and human potencies match more closely when a mg/kg/day basis is used (Crump at al., 1985). We are currently working on a project for EPA to extend this work and preliminary results seem to corroborate this finding. Potency estimates in Table 8 for benzene were made from human data and consequently no animal-human conversion approach is required. The potencies reported for benzene under the ppm and mg/kg/day conversion approaches are from the absolute risk weighted cumulative exposure model and those reported under the mg/m2/day conversion approaches are from the relative risk cumulative exposure model (Crump and Allen, 1984). Crump and Allen's Table 21 was used to obtain maximum likelihood estimates of risk and that table, in conjunction with their tables 12 and 15, were used to compute qi*s appearing in Table 8 and .corresponding upper limits of risk. Exposure estimates Estimates of exposure were made for the residential area c u located south of the landfill, north of Amar Street and roughly east of Westport Street. This appears to be the residential area most heavily impacted by the landfill. Exposures were estimated for the period 1978-1985, which we understand is the period of concern. Estimates were developed using the South Coast Air Quality Management District (SCAQMD) monitoring data only and also by supplementing this data with monitoring data collected by the Engineering Program of the University of Southern California (U.S.C., 1980). All SCAQMD monitoring stations in the residential area of concern were identified. These are listed in Table 9 along with the numbers of samples for vinyl chloride by year. Except for the three month period from July 19 to October 15, 1982 monitoring data was available from SCAQMD for vinyl chloride only. Exposures to vinyl chloride were recorded by SCAQMD down to a detection limit of 2 ppb during 1983 to 1985 ("fine" recording approach). 0 During 1981 and 1982 SCAQMD recorded vinyl chloride measurements in increments of 10 ppb, with lowest measurements entered as <10 ppb ("coarse" recording approach). For the first six months of 1983 monitoring data were available using both methods of recording. For exposures recorded down to 2 ppb, average exposures were obtained by substituting 1 ppb for values recorded as <2 ppb. The effect of this approach was investigated by repeating some of the analyses substituting 2 ppb for values recorded as less than 2 ppb. Using 2 ppb instead of 1 ppb for values recorded as <2 ppb only increases the estimate of average levels for 1981 through 1985 by 10S. Thus the average levels do R&S 152026 ( 12 not appear to be sensitive to the approach taken for values recorded as <2 ppb. To estimate levels recorded as <10 ppb during 19B1-1982, the data for 1983 containing both "fine" and "coarse" measurements were used to help estimate average levels for various cat gories of coarse estimates available for 1981-82. Averages of th fine measurements * during the first 6 months of 1983 for samples for which the coarse measurement was <10 ppb was used to estimate the average level during 1981-82 for samples recorded as <10 ppb. for measurements recorded as 10 ppb during 1981-82. an average of 12.5 ppb was used because it appeared from the 1983 data that 10 ppb was recorded as the coarse measurement when the fine reading was between 10 and 15 ppb; otherwise the recorded value was used in determining the average levels for 1981-82. The effect of this approach was evaluated by comparing the average estimates obtained for July 19 - October 15, 1982 period with those obtained # independently for this period by California Department of Health Services et~al. (1983) for which they apparently had access to the fine measurements. Our estimated average level for Station A using the approach described above was 10% below their estimate and our estimated level for station n was 33% below theirs. To adjust for this, our estimates for Station A (#2) during 1981-82 were multiplied by 1.1 and our estimates for Station B (#1) wer multiplied by 1.33. Estimates for station #3 and #4 were multiplied by an intermediate value ithe square root of the product of these two factors). These approaches were used to obtain estimates for exposure R&S 152027 C 13 to vinyl chloride for each quarter that SCAQMD had collected data. A quarterly estinate was obtained by averaging all of the data obtained during that quarter from the stations listed in Table 9. This provided average levels of vinyl chloride for each quarter, beginning with the second quarter in 1981, through 1985. Average levels' throughout a period were estimated by averaging quarterly levels, giving all quarters equal weight. The background level of vinyl chloride was assumed to be 2.5 ppb, which is the average of the values reported for Station C by California Department of Health Services et al. (1983, Table II). The level of vinyl chloride attributable to BKK was estimated by subtracting this background level from estimated average levels. Average quarterly levels for the other six chemicals were estimated from the data in Table II of the California Department of Health Services et al. (1983) report by averaging the levels for the chemical of interest at Stations A and B, subtracting the average level at_Station C (background level), and multiplying by the ratio of the average level above background for vinyl chloride estimated as described above to the average level above background at Stations A and B for vinyl chloride in Table II of the California Department of Health Services et al. report. The approaches described thus far provide estimates of average exposures to the seven chemicals of interest for the period covering the second quarter of 1981 through 1985. Tw different approaches were employed to estimate exposures from 1378 through the first quarter of 1981. The first method (the "SCAQMD approach") involved assuming that averag levels found for the R&S152028 R&S 152029 c0 14 period from L978 through the first quarter of 1981 were equal to the average levels estimated for the earliest year for which SCAQMD monitoring values were available (first quarter 1981 through first quarter 1982). The second method involved use of monitoring data collected * during the spring of 1980 by the Environmental Engineering Program of the University of Southern California (U.S.C., 1980). In this program 54 air samples were taken at several sampling sites and analyzed by GC/MS for a variety of volatile organic-chemicals.. All of the seven volatile chemicals under consideration were detected in this program except for vinylidene chloride. Sixteen of the samples were collected at the four sampling sites in the residential area under consideration: Rl (4 samples), R2 (6 samples), R3 (2 samples), R4 (4 samples). Average levels for the entire residential area were obtained by averaging the levels of each of the seven'chemicals found in these sixteen samples. For each chemical except vinylidene chloride, whenever none was found the lowest value recorded in the sampling program was assumed; it was assumed that no vinylidene chloride was present. The average values so obtained are shown in Table 10. The large estimate obtained for benzene is due in large part to two very large measurements -- 88 and 67 ppb -- obtained at Station R4 on the same day. Since these large values possibly are not related to BKK, Table 10 also contains an estimate for benzene with these large samples omitted. In the second method for estimating exposures for the earlier period (the "USC method"), averages from Table 10 obtained using c 15 the USC data are assumed to hold for the period 1978-1980 and the SCAQMD approach is applied only to the period 1981-1985. Risk estimates Estimates of risk obtained by applying the results from the multistage model shown in Tables 1-6,8 to the exposures estimated as described in the previous section are shown in Table 11. The 95% upper limit estimates of risk for individual chemicals are obtained by multiplying the average exposures of humans in ppm times the fraction of a normal life span for which these exposures occurred by the appropriate human potency estimate from Table 8 in units of [ppm*1]. The identical approach, except applied t th maximum likelihood estimates of the q's (displayed in Tables 1-6) rather than to the qt"s are used to obtain maximum likelihood estimates of risk. Risk estimates pertaining to individual chemicals are summed to obtain estimates of total risk. The risks shown in Table 11 are based upon the rag/kg/day method for converting from animals to humans. As discussed earlier, data on chemicals for which both animal and human data are available indicate that this dose measure provides the best., correlation between estimates of cancer risk derived from human and animal data. To calculate upper limits based upon, say, the mg/m2/day method of converting from animals to humans, it is only necessary to multiply the upper limit risks in Table 11 by the ratio of the qi in Table R derived using the mg/m4/day conversion method to the corresponding qi* derived using the mg/kg/day conversion method. R&S152030 V 16 R&S 152031 Discuss ion The risk estimates in Table 11 all range between 2.5 and 11 per million. It should be kept in mind that they were derived assuming continuous exposure 24 hours per day for 8 years. Typical year round occupancy of a home is probably no more than 12 hours per day. Thus risks in the range of 1.25 to 6 are more appropriate for the typical occupant. These estimates are conservative in other ways also. All of the upper limits estimates were derived from a linear dose response model: such models are unlikely to underestimate risk, but would likely overestimate risk by a considerable amount if the linear hypothesis is not valid. The estimates determined from animal data were based generally on the single data set from an inhalation exposure study that provided the highest estimate of risk. Adding statistical upper confidence limits on risk from individual chemi.cals to obtain an upper limit for total risk will give an exaggerated upper confidence limit for total risk. To place the risks estimated in Table 11 into perspective, it is useful to compare them to risks from other activities. The following comparative risk estimates were made using methods commensurate with those applied in this report: Risk/Million Living in a brick house for life (low-LET radiation) 56 Living in Denver 8 years vs. living in Los Angeles (cosmic radiation) 29 Smoking one pack of cigarettes (lung cancer) 12 Accident during typical 2-day business trip 3 17 References California Department of Health Services Toxic Substances Control Division et al. (1983). Ambient Air Monitoring and Health Risk Assessment for Suspect Human Carcinogens Around the BKK Landfill in West Covina. (unpublished report). Crump, K. (1985). Methods for carcinogenic risk assessment. Principles of Health Risk Assessaent. Ricci, P. (ed.). Prentice-Hall. pp. 279-319. Crump, K. S. *(1982). Quantitative Assessment of Human Risk from Exposure to Carcinogens with Special Reference to Vinyl Chloride. Prepared for the Ontario Ministry of Labour, Occupational Safety and Health Division. Crump, K. and Allen, B. (1984). Quantitative estimates of risk of leukemia from occupational exposure to benzene. Prepared for OSHA. Crump, K. S. and Howe, R. B. (1985). Review of methods f r calculating statistical confidence limits in low dose extrapolation. Toxicological Risk Assessaent, Volume I. Clayson, D., Krewski, D., Monroe, I., (eds.). CRC Press, Inc. Boca Raton, Florida. Crump, K. S., Silvers, A., Ricci, P. f., and Wyzga, R. (1985). Interspecies Comparison for Carcinogenic Potency to Humans. In: (Paolo Ricci, ed.) Principles of Health Risk Assessaent, Prentice-Hall, pp. 321-372. Fukuda, K. , Takenoto, K. and Tsuruta, K. (1983). Inhalation carcinogenicity of trichloroethylene in mice and rats. Industrial Health 21:243-254. Gehring, p. j.f Watanbe, P. G. and Park, C. N. (1978). Resolution of dose-response toxicity data for chemicals requiring metabolic activation: example--vinyl chloride. Toxicology and Applied Pharaacology 44:581-591. Henschler, D., Rosen, W., Elsasser, H. M., Reichert, D., Eder, E. and Radwan, Z. (1980). Carcinogenicity study of trichloro ethylene by long-term inhalation in three animal species. Archives of Toxicology 43:237-248. Jorgenson, T. "A. , Meierhenry, E. F., Rushbrook, C. J.f Bull, R. J. and Robinson, M. (1985). Careinogenicity of chloroform in drinking water to male Osborno-Mendel rats and female B6C3F1 mice. Fundamental and Applied Toxicology 5:760-769. Lee, C. C., Bhandari, J. C., Winston, J. M., House, W. B., Peters, P. J., Dixon, R. L. and Woods, J. S. (1977). Inhalation toxicity of vinyl chloride and vinylidene chloride. Environmental Health Perspectives 21:25-32. R&S152032 VC 18 Maltoni, C.t Ciliberti, A., Carretti, D. (1982). Experimental contributions in identifying brain potential carcinogens in the petrochemical industry. Annals New York Academy of Science 381:216-249. Maltoni, C,, Lefermire, G., Ciliberti, A., Cotti, G. and Carretti, D. (1981). Carcinogenicity bioassays of vinyl chloride monomer: a model of risk assessment on an experimental basis. Environmental Health Perspectives 41:3-29. Maltoni, C., Valgimigli, L. and Scarnato, C. (1980). Long-term carcinogenic bioassays on ethylene dichloride administered by inhalation to rats and mice. In: Banbury Report 5, Ethylene Bichloride.* A Potential Health Risk? Ames, B., Infante, P. and Reitz, R. (eds.). Cold Spring Harbor Laboratory. National Toxicology Program (1985). The Toxicology and Carcino genesis Studies of Tetrachloroethylene (derchloroethlen ) (CAS No. 127-18-4) in F344/N Rats and B8C3F1 Mice (Inhalation Studies). NTP TR 311. NIH Publication No. 85-2567. U.S.C. (1980). Second Interim Report: Investigation of odorous and Volatile Compounds for BKK Class I Landfill Site in th City of West Covina. Environmental Engineering Program, University of Southern California Viola, P. L. and Caputo, A. (1977). Carcinogenicity studies on vinylidene chloride. Environmental Health Perspectives 21:45-47. R&S 152033 19 TADLB 1 Pit of Multistage Model to Vinyl Chloride Data on Rats with Liver Angiosarcoma fron Maltoni at al. (19B1) F.xper i mental Data* Melaho) t zed Tumor Dj>e (Pit) Incidence 0 0/461 Maxinum Likeli hood Estimates i of Parameters 95t Upper Limit on Risk foi*) qo = 0 4.8556B-5 Qoodness-of-Pit Test Results Degrees of chi-square Freedom p-value 15.7873 10 0.1059 16.9 0/118 qi = 3.833B-50 83.8 0/119 qa = 0 A U M O 165 1/119 395 5/120 q = 0 739 15/354 qs = 0 1309 1/120 qo =0 1761 6/119 qr = 0 2129 12/120 q8 = 7.007B-32 2435 3/59 q* = 0 3413 6/60 q> o - 0 5030 13/60 qi i = 0 5403 13/59 qi z * 0 1 Mu 11 on 1 el al. (1982) r port the results of several experiments that used u common (uulocul (designated DTI, HT2, BT6, DT9, DT15), which have been combined Tor this unulysis. *3.0H3li-5 incnns 3.883x10-*. R&S152034 20 TABLE 2 i Fit of the Multistage Model to Tetrachloroethylene Data oo Mule Mice with Hepatocellular Carcinoaa froa National Toxicology Prograa (19B5) Expert men ta1 Data* Dose Tumor Level (ppm) Incidence 0 7/49 Maximum Likeli hood Estimates of Parameters 95* Upper Limit on Risk (qi) * qo.= 1.7677E-1* 4.9588B-3 100 25/49 qt = 3.5523E-3 200 26/50 q2 = 0 1.7677E- 1 neans 1.7677x10-*. Goodness-of -Fit Tes t Res uIts Degrees of chi-square Freedora p-value 3.0201 1 8.224E-2 seosstssa ? TABLE 3 21 I Fit of the Multistage Model to Trichloroethylene Data on Feaale Mice. Total Malignant Tuaor Bearing Aniaala fro* Renschler et al. (1980) Experimental Data* Dose Tumor Level fppml Incidence Maximum Likelihood Estimates _ of Parameters 95* Upper Limit on Risk (at*) 0 13/29 Iqo = 7.6303E-1* 3.6006E-3 > 100 22/30 91 = 1.9002E-3 500 22/28 92 = 0 1 .7677E-i means 7.6303x10-'. Goodneas-of-Fit Test Results Degrees of chi-sauare Freedom p-vaine 2.8603 1 9.079IE-1 S /'"V 4 geossts'SB ) 22 TABLE 4 Fit of the Multistage Model to 1,2-Dichloroethane Data on Mole Rats. Total Tumor Bearing Animals from Maltoni et al. (1980). Experiments 1 Data* Dose Tumor Levelt(ppm) I ncidance 0 0/90 Maximum Likeli hood Estimates of Parameters |1 qo = 9.4636E-2* 95k Upper Limit on Risk (qi*) 2.4877E-4 5 11/90 qi = 2.4077E-4 10 5/90 qz =0 50 10/90 qi = 0 250-150 11/90 q* = 0 * 9.4636E-2 means 9.4636x10-*. Goodness-of -Fit Tes t Res ult s Degrees of chi-square Freedom p-vulue 2.5902 3 4.5921E-) zeozsisstd 23 TABLE 5 Fit of Multistage Model to Vinylidene Chloride Data on Male Rats with Bruin Tuaors froa Maltoni et at. (19B2) Experimenta1 Data* Dose Tunor Level fppm) Incidence 0 3/100 Maxinua Likelihood Bs tiaatea of Parameters 1' qo = 2.1661E-2* 95* Upper Liait on Risk {qi* 1 1.3749B-4 o II 10 1/30 25 0/30 q2 = 0 50 2/30 qa = 0 100 0/30 q = 0 150 0/60 qs = 0 *2.1661E-2 neans 2.1661x10-2. Goodness-of-Fit Test Results Degrees of chi-souare Freedom p-value 6.1007 5 2.9579E-I 8E03S1- S'Sd 24 TABLB 6 Fit of the Multistage Model to Chloroform Data on Male Ruts. All Kidney Tumors from Jorgenson et nl. (I9B5). Experiment a 1 Data* Dose Tumor Level !(tnjf / 11 Incidence 0 6/351 Maximum Likelihood Rs timutes of Parameters I qo = 1.5845E-2* 95* Upper Limit on Riak fqi* 1 1.0448B-4 200 6/313 qt = 4.4481E-5 400 7/148 q2 = 1.74B2B-8 900 1 BOO 3/4B 7/50 qi =0 q = 0 *1.58158-2 means 1.5845x10"2. Ooodneas"of-Fit Test Results Degrees of chl-aouare Freedom p-va|ne 1.0856 2 5.fill2E-1 6E0SS|.S'S'H 25 TABLE 7 Standard Values Used in Dose Conversions Body Species - Weight (Vg) Mouse 0.03 Rat 0.35 Human 70.0 Breathing Rate fm'/dav) 0.05 0.26 20 Natural Life Span <weeks) 104 104 3640 (70 years) TABLE 8 Human Potency Estimates (Qi"s) Vinyl chloride Tetrachloroethylene Trichloroethylene Vinylidene chloride Ethylene dichloride Chloroform Benzene Vinyl chloride Tetrachloroethylene Trichloroethylene Vinylidene chloride Ethylene dichloride Chloroform Benzene Dose Measure Assumed to Provide Eouivalent Risks in Animals and Hunan: d Dm mtf/ke/dav rae/n*/da* Units of (ppo)~l 1.11E-02 4.27E-03 2.50E-02 2.78E-02 4.76E-03 6.32E-02 2.18E-02 3.73E-03 4.95E-02 1.81E-03 6.95E-04 4.0SE-03 4.02E-03 1.55E-03 9.05E-03 3.18E-03 1.22E-03 7.16E-03 1.56E-02 1.56E-02 1.11E-01 Units of (mg/kg/day) -1 1.52E-02 5.83E-03 3.41E-02 1.43E-02 1.42E-02 1.S6E-03 3.47E-03 2.28E-03 1.56E-02 2.45E-03 2.43E-03 5.99E-04 1.34E-03 8.75E-04 1.56E-02 3.25E-02 3:22E-02 3.50E-03 7.81E-03 5.12E-03 1.1IE-01 f 0 27 TABLE 9 List of SCAQMD Monitoring Stations Used to Estimate Vinyl Chloride Exposures with Number of Measurements Available by Year Station1981 1(B) 2(A) 3 4 A B N East Bankuthy Lo My (Myra- Court)- 2711 Miranda 2715 Miranda 2600 Maureen 192 192 32 56 19B2 316 319 1983 254 252 1984 1985 304 305 33 10 1 33 172 209 52 13 321 288 122 306 R&S152042 28 TABLE 10 Average Exposures Obtained from Sixteen Air Staples Collected at Four Residential Sites in the Spring of 1980 by the University of California Vinyl chloride Tetrachloroethylene Trichloroethylene Vinylidene chloride Ethylene dichloride Chloroform Benzene Benzene (omitting two large outliers collected on a single day) ppb 1.25 3.43 0.81 0 2.24 1.14 16.0 7.59 R&S152043 29 TABLE 11 Estimates of Average Air Concentrations from 1978 to 1985 and Resulting Risks Assuming 24 Hour Per Day Exposure Air Concentration foob) Extra Risk per Million Best (ML) 95% Upper Estimate Limit . "SCAQMD Method" for Estiaating Average Air Concentrati ns Vinyl chloride Tetrachloroethylene Trichloroethylene Vinylidene chloride Ethylene dichloride Chloroform Benzene Total Risk 3.637 0.732 0.859 0.833 1.440 0.025 0.556 1.24 0.25 0.17 0 0.07 0.001 0.77 2.50 1.78 0.40 0.37 0.07 0.25 0.004 0.99 3.86 "USC Method" for Estiaating Average Air Concentrati ns Vinyl chloride Tetrachloroethylene Trichloroethylene Vinylidene chloride Ethylene dichloride Chloroform Benzene Total Risk 1.497 0.874 0.564 0.343 1.227 0.287 5.383 0.51 0.30 0.11 0 0.06 0.02 5.65 6.65 0.73 0.48 0.24 .0.03 0.22 0.04 9.60 11.33 "USC Method", Eliainat ng Two High Benzene Measurements Benzene Total Risk 2.212 2.32 ________ 3.94 3.32 5.68 R & S 152044 (0 ADDENDUM TO ESTIMATES OF CARCINOGENIC RISK IN THE VICINITY OF THE BKK LANDFILL K S CRUMP and Co., Inc. 1201 Gaines Street Ruston, La. 71270 Date of Addendum: April 4, 1986 It has been noted that the Californio Air Resources Board and the Department of Health Services (ARB and DOHS, 1984) estimated that the ambient concentration of benzene in the South Coast Air Batin (SCAB) was 4.6 ppb during 1981 and 1982. According to Figures 1 and 2 of Appendix E of ARB and DOHS (1984). it appears that the ambient concentrations at West Covina were close to the average of 4.6 ppb. The period for which this estimate was made is included in the period of assumed exposure from BKK (1978 to 1985). Also, the data upon which the ARB and DOHS estimate is based is much more extensive than that gathered during the period July - October, 1982 and which.was used in our March 1981 document to estimate ambient exposures. Thus we conclude that 4.6 ppb is a more reliable estimate of the ambient exposure to benzene near BKK during 1978 to 1985 than the estimate used in our March 1 document. If 4.6 ppb is used as the ambient level of benzene, the resulting air concentrations above ambient and corresponding risks are contained in the attached revision to Table 11. (c 2 The risks estimated for BKK may be compared to the following: Occupational exposure to passive smoke for 8 years Oeaths/Miliion 320 Drinking one diet soft drink per day for life (saccharin) Living in a brick house (low LET rodiation) 170 56 Living in Denver 8 years vs. living in Los Angeles (cosmic radiation) Eating peanut products 29 (aflatoxin. U.S. average consumption) n Driving for one month (1000 miles) on Los Angeles freeways (California urban interstate highways) One chest x-ray 6.7 1.5 Each of these risks was calculated using methods similar to those used for BKK. Details can be made available upon request. Reference ARB and DHS (1984). Report to the Scientific Review Panel on Benzene. Prepored by the Staffs of the Air Resources Board and the Department of Health Services. November. R&S 152046 (c 3 TABLE 11 (Revised) Estimates of Average Air Concentrations Above Ambient from 1978 to 1985 and Resulting Risks Assuming 2% Hour Per Day Exposure Air Concentration ________ (ppb) above ambient gmbient Extra Risk per Million Best (ML) 95* Upper Estimate______ Limit *SCAQMD Method* for Estimating Average Air Concentrations Vinyl chloride Tetrochloroethylene Trichloroethylene Vinylidene chloride Ethylene dichloride Chloroform Benzene Total Risk 2.5 1.9 0.25 0.20 0.55 0.A0 4.6 3.637 0.732 0.859 0.833 1.440 0.025 0.0 1.24 0.25 0.17 0 0.07 0.001 0.0 1.78 1.78 0.40 0.37 0.07 0.25 0.004 0.0 2.97 *USC Method* for Estimating Average Air Concentrations Vinyl chloride Tetrochloroethylene Trichloroethylene Vinylidene chloride Ethylene diehloride Chloroform Benzene Total Risk 2.5 1.9 0.25 0.20 0.55 0.40 4.6 1.497 0.874 0.564 0.343 1.227 0.287 4.515 0.51 0.30 0.11 0 0.06 0.02 4.74 5.74 0.73 0.48 0.24 0.03 0.22 0.04 8.05 9.78 USC Method*. Eliminating Two High Benzene Measurements Benzene Total Risk 4.6 1.12 1.18 3.17 2.00 3.73 R&S 152047 APPENDIX D R&S152048 Bisk Assessment for Exposure to Ambient Air in the Vicinity of the BKK Landfill in West Covina. 1978-1985 Kenneth T. Bogen. Dr.P.H. Martyn T. Smith, PbuD. Health Risk Associates P.0. Box 9529 Berkeley, CA 94709 1. Introduction The BKK landfill in West Covina has been in operation as a repository for toxic waste since 1976. Some of the residents in the vicinity of the landfill have complained that substances in the landfill are causing them to suffer an increased risk of disease and have asked that the landfill be closed. In 1983. the California Department of Health Services (DHS) ef of. (DHS 1983) issued a report which contained measurements of the ambient air concentrations of volatile organic compounds, which the Department considered to be potential human carcinogens, and also reported corresponding measurements at a con* trol site located 9 miles away. These measurements were used as a basis for cal culation of the excess cancer risk associated with residence near the BKK landfill (DHS 1983, attached as Appendix l). A review of the DHS 1983 report indicated that it was not possible to reproduce this calculation since no infor mation was given with regard to what animal cancer tests were used or how cer tain factors, such as meteorological conditions, were accounted for. We were therefore asked to perform our own calculation of the excess cancer risk that may be incurred by residence in the vicinity of the BKK landfill during a 7-year period between 1978 and 1985. Our analysis uses data from exposure monitor ing and from animal experiments along with a variety of methods and assump tions that are used by the U.S. Environmental Protection Agency (EPA), plus several new methods that have been developed recently. Section 2 describes these methods. Section 3 reports the results of the calculations we made, and " Section 4 discusses these results. 2. Methods In order to predict increased lifetime cancer risk, it is necessary in *h' case to calculate both a dose and a carcinogenic potency for each of the com pounds to which individuals are purportedly exposed around the BKK landfill. Dose is, of course, calculated from the available exposure information. Carcino genic potencies are derived from the selected animal bioassay data. Our assumptions and methods regarding the calculation of exposure and potency are described below. 2.1. Methods & Assumptions Regarding Exposure Assessment In the absence of detailed information on exposure in the vicinity of the BKK InndflU. a number of assumptions were made regarding how to interpret the concentration data available to us as well as how to estimate duration of exposure, dilution of ambient contaminant concentration, absorption of inhaled compounds and. finally, the impact of seasonal concentration variability. These assumptions are described below. 2.1.1. Concentration Data It Is assumed that the mean ambient air concentrations (Le., the mean value of the 2 [l in the case of benzene] compound-specific mean concentra tions) reported in DKS (19B3) equal the actual time-weighted average (TVfA) concentrations for the seven compounds measured, over the 7-year period of interest. These data were collected at 4- monitoring stations (Stations A. B. D. and F) located on the perimeter of the BKK landfill, as well as at a control moni toring station located 9 miles away (Station C). It is also assumed that the rela tive ratios of the latter values accurately reflect the relative contribution of each compound to total exposure over this period, for each monitoring station. For the purpose of our analysis, we have further assumed that the TWA concentrations at the stations on the perimeter of the BKK landfill and those at the control station are in fact different, That is, we assume that the DK5reported differences between the mean concentrations for Stations A. B, D and F. on the one hand, and Station C, on the other, are not due purely to chance. 52052 If a proper statistical analysis of the the actual concentration measurement data indicate that the latter differences are in fact due to chance, then the excess risk is of course 0 without reference to any further assumptions. Since the raw concentration data were unavailable to us, vre are unable to evaluate the likelihood of this possibility. Increased concentrations of the 7 contaminants measured by DHS in the BKK vicinity above the corresponding control station values were calculated for stations A, B, D and F in terms of mg/kg/day. These values are given in Appen dix 2. Mote that for Station F, the mean of the measured values is less than the corresponding control station value for benzene and chloroform. 2.1.2. Exposure Duration Here we assume that exposed residents are present in the vicinity of the BKK landfill for an average of IS hours per day. for 365 days per year over a 7year period. 2.1.3. Concentration Dilution We assume that concentrations reported on the perimeter of the landfill are dispersed in the ambient air to some degree before being inhaled by the average resident, and that this process reduces the average concentration to which residents are exposed by a factor of 2. We further assume that no addi tional dilution takes place (e.g.. due to filtration by air conditioning). 2.1.4. Absorption We assume residents' average respiratory intake rate is 20 m3/day per 70 kg body weight (Le., 0.2357 m3/kg/day). In their analysis of cancer risk due to household exposure of chlorinated hydrocarbons, such as those considered here, Cothern et ai. (1984) make the assumption that 50% of the amount of such compounds contained in inhaled air is absorbed into to blood and is R&S152053 <! -4- 0 distributed via circulation., and the balanced is exhaled back into the atmo sphere. We follow the Cothern et al. assumption of 50 absorption (i.e.. SOZ retention) of contaminants contained in respired air. 2.1.5. Seasonal Variation in Concentration It is possible that the release of volatile organic compounds, such as those considered here, from the surface of the BKK landfill may be enhanced with increasing temperature, resulting in increased ambient concentration during the warmer months of the year. We note that the DKS concentration measure* ments were made between July and October of 19S2. Since these months are the warmest of the year in southern California, these measurements may overestimate TWA concentrations at other times of the year. In the absence of other measurements, however, we make the conservative assumption that the DKS measurements accurately reflect TWA concentrations over the multi-year period of interest without seasonal adjustment. 2.2. Methods lc Assumptions Regarding Carcinogen Potency Assessment Since the mid-1960s, the primary basis for judging both carcinogenicity (Le., carcinogenic potential) per se and the carcinogenic potency of particular chemicals to humans, in the absence of adequate epidemiological data, has been data from long-term carcinogen bioassays using laboratory animals. By this means, an assessment of human carcinogenic potency of a compound at very low environmental dose levels begins with an assessment of tumorigenie potency at much higher experimental dose levels in the test species used. This is followed first by an extrapolation of expected response in that species from these experimental dose levels down to the environmental levels of interest, then by an extrapolation of the latter predicted response, in the test species used, to a response in a target human population. R&S152054 ( -0* 1 The validity of risk predictions calculated in accordance with the above procedure, of course, is conditional on the validity of key assumptions or "infer* ence bridges" that must be used to bridge fundamental gaps that currently exist in basic scientific knowledge concerning the mechanism of carcinogenesis, the extrapolation of high*dose observations to low*dose predictions for & given species, and the equivalence of tumorigenic doses between different species. Environmental cancer risk assessment cannot proceed without the use of these assumptions, so that much effort has gone into studying how they may stand ardized for use in a regulatory context (NAS 1983). But this does not mean that the uncertainty associated with these assumptions is in any way irrelevant or negligible, or even that their use will necessarily lead to risk predictions that are consistent with the "best guesses'* of a majority of informed scientists/exp erts. In certain components of our potency assessment we have made use of some of the assumptions and procedures that have become standard in the context of regulatory carcinogen risk assessment. But in other components of our analysis, we have made use of a range of plausible assumptions (rather than a single conservative assumption) in order to lend a greater degree of objec tivity to the analysis. The validity of the final result, however, remains condi tional on the validity of the residual set of inference bridges we have used for this analysis. The following subsections discuss the specific methods and assumptions we use for carcinogen potency assessment in the present analysis. 2.2.1. Selection of Animal Data The animal data we used for each compound were derived from EPA Health Assessment Documents when these were available. In the absence of such docu ments (for the cases of the 2 known human carcinogens vinyl chloride and R&S152055 benzene), data from the scientific literature were selected m general accor dance with EPA's preferred selection criteria. The latter criteria are eonreT-i/ative in the sense that efforts are made to err on the side of safety by generally focusing on data obtained for the most sensitive species/strain/sex tested while ignoring the weight of evidence for non-carcinogenicity or for less potent carcinogenicity presented by any remaining data (EFA 1984a). Below we describe the specific data sources we used in our potency assess ment. The actual dose-response input data used and related information appears in Appendix 2. We note that in the health assessment documents for the five compounds for which EPA has produced such documents to date, animal dose levels used to extrapolate tumorigenie response for given bioassay data sets represent life time TWA metabolized doses. In these eases, and in the case of vinyl chloride discussed below, dose levels were (linearly) transformed baclc into an applied dose level that corresponds with expected applied low-level dose, fully in accor dance with the pharmacokinetic data reUed on in each case for determining metabolized dose. The latter transformation obviates the need to readjust cal culated potencies that are based directly on a metabolized dose, rather than on an applied dose such as that calculated for BKK-vieinity residents. (See, how-. ever, the discussion of vinylidene chloride bioassay data below.) We note finally that in certain cases several animal bioassay data sets are discussed and analyzed in EPA health assessment documents, whereas only a subset of these are actually used' to calculated potency values recommended for use (albeit, for use in a regulatory context) by EPA. We have made use of only data sets relied on by EPA for final potency assessment in these cases. 1. Vinyl Chloride (VCL). No EPA health assessment document exists for VCL at this time. For potency assessment, we used the data of Maltoni and LeFem- c -7- r \ ine (1975) on the induction of zymbal gland tumors, nephroblastomas and liver angiosarcomas in female Sprague-Dawly rats exposed to VCL by inhalation. The experimental exposures in this study (0. 50. 250. 500. 2500, 6000. and 10000 ppm) were converted to lifetime TWA exposures in mg/kg/day using standard assumptions employed by EPA (Anderson ef al. 1983. EPA 1934a). In addition, the resulting animal TWA doses were adjusted to reflect non*linear metabolism of VCL by rats at these concentrations, in accordance with the pharmacokinetic analysis done by Gehring ef al. (1978). 2. Perchioroethylene (PCE). Bioassay data on PCE liver carcinogenicity in B6C3F1 mice have been used by EPA to extrapolate carcinogenicity at low doses (EPA 1984b). More recent bioassay data have been produced by the National Toxicology Program which may also be used to evaluate the carcinogenic poten tial of PCE (NT? 1985). See discussion in Section 2.2.2 regarding our omission of PCE data. 3. Trichloroethylene (TCE). Bioassay data on TCE liver carcinogenicity in B6C3F1 mice have been used by EPA to extrapolate carcinogenicity at low doses (EPA 1985a). See discussion in Section 2.2.2 regarding our omission of TCE data. 4. Vinylidene Chloride (VDCL). We make use of bioassay data on VDCL's capacity to induce kidney adenocarcinomas in male Swiss mice reviewed in EPA (1985b). EPA's derivation of dose data for this bioassay relies on experimental information regarding VDCL metabolism in rats and mice. For potency assess ment. EPA assumes lOOE metabolism of VDCL. and so uses caiculated metabol ized dose directly in its potency assessment. However, the metabolic data relied on by EPA for VDCL potency assessment show that 0.035 kg mice and 0.25 kg rats exposed to 10 ppm VDCL for 6 hours metabolize 0.188 mg and 0.723 mg VDCL, respectively. But using EPA's recommended method to calculate mouse R&.S152057 cc - s - respiration rates in the context of cancer risk assessment (E?A 1994a), the corresponding inhaled amounts (which equal the respective applied doses only if 100" absorption is assumed--see discussion above) are JUtruss: 97 g/M 10 ppm x 24.45 1/ M x 0.0345 2/3 0.035 0.025 m3/ day x 6 hr 24 hr/ day 0.4252 Bat- 10 ppm x 97 g/M 24.46 L/M 0.105 0.25 0.113 2/3 m3/ day 8 hr 24 hr/ day 1.76Sn That is. 43% and 45% of applied dose is metabolized by mice and rats exposed to 10 ppm VDCL for 6 hours, respectively. Since metabolic saturation in these species occurs at a much greater dose level than 10 ppm. it may be argued that the appropriate applied dose data to use for mice in analyzing the VUCL bioas say data can be linearly extrapolated down to the ppb range of interest. Le.. that the dose data should be increased by a factor of ^ = 2.3 over the ' 0.43 figures used by EPA. We did not correct for this source of potential conserva tism in deriving appropriate dose data to use in the analysis of the VDCL bioas say data, but rather used EPA's dose data directly. 5. 1.2-Dichioroethane (DCE). We make use of bioassay data on DCE's capa city to induce hemangiosarcomas in male Osborne-Mendel rats and hepatocellu lar carcinomas in male B6C3F1 mice reviewed in EPA (l9B5c). 8. Chloroform (CU3I). We make use of bioassay data on CLFM's capacity to induce hepatocellular carcinomas in male and female B6C3F1 mice reviewed in EPA (I985d). 7. Benzene (BNZ). No EPA health assessment document exists for BNZ at this time. For potency assessment, we used the data of Maltoni (19B3) on zymbal gland tumor induction in female Sprague-Dawly rats exposed to BNZ by ingestion. Metabolism was not taken into account regarding the dose levels in R&S152058 c C- 9 - this data set. 2.2.2. Dose-Response Extrapolation The extrapolation of observed response in animals at experimental doses to predicted response at lew doses can be strongly influenced by the model used to carry out this extrapolation. This is clearly illustrated in Cothern et al. (1984). EPA uses the "linearized multistage" model to extrapolate lifetime human cancer risk at very low dose levels based on a given set of animal carci nogenicity bioassay data (Anderson et al. 1993, EPA 1984a). This method yields an upper (one-tailed) asymptotic 95Z confidence limit of low-dose potency for a given input data set. The uncertainty referred to by this confidence limit is that due only to estimation error in fitting the multistage model, where this model is simply assumed to be correct for the purpose of doing a quantitative potency analysis. This dose-response model is such that risk is approximately equal to dose multiplied by potency at very low dose levels, such as the levels we con sider here. In addition, low-dose potency and risk extrapolations generated by the multistage model are conditional on the assumption that the compounds whose potencies are extrapolated are indeed human carcinogens at low doses. While in a regulatory context, a number of consen/ative, safety-oriented assumptions have been adopted to enable analysts to predict the cancer risks which may possibly be associated with exposure to certain compounds (MAS 1933, EPA 1984a). these assumptions do not necessarily provide the most likely or most reasonable estimate of risk given current scientific knowledge. Accordingly, we do not feel that the compounds PCE and TCE should be included in our assess ment of the most Likely risk associated with exposure to emissions from the BKK landfill. This is because both of these compounds are unlikely to be actual human carcinogens at the low doses considered in this analysis. Both - :q - C compounds produce tumors m the livers of B6C3F1 mice and do not do so in the livers of rats. The B6C3F1 mouse is extraordinarily susceptible to liver cancer, possibly because of the presence of an oncogene in its liver cell DNA (Fox and Watantabe 1985). Therefore, any agency which produces toxicity in the livers of B6C3F1 mice is more than likely to produce liver tumors by stimulating cell proliferation rather than by causing genetic damage. Recent studies by Mirsalis ef al. (1985) using both TCE and PCE support this proposition. Le.. that TCE and PCE produce liver cancer in BSC3F1 mice by an epigenetic toxic mechanism. Furthermore, mice do not metabolize TCE in the same manner as humans and do so at a much faster rate than either rats or humans. Since neither TCE nor PCE nor both will produce liver toxicity in humans at the low doses being con sidered here, they are extremely unlikely to produce liver cancer in the human population concerned. When more than one data set is used to calculate carcinogenic potency. EPA uses the geometric mean of the calculated asymptotic upper confidence limits based on those data sets as an overall estimate of potency. The latter procedure, for instance, was used in EPA's recent calculation of TCE*s carcino genic potency based on A bioassay data sets (2 sexes in 2 different studies) (EPA 1984b). For the purpose of deriving a lifetime tumorigenic potency assessment which takes a more objective approach to the uncertainties arising in doseresponse extrapolation, we have used an alternative to EPA's method, called the Monte Carlo Potency Analysis (MCPA) method, to assess carcinogenic potency under different assumptions, such as regarding which data set to use (or how to do inter-species dose extrapolation, discussed below). The MCPA method uses the same multistage model used by the EPA method. However, the MCPA method relies on Monte Carlo simulation, rather than the more conservative cc -11 - and approximate asymptotic approach used in the E?A method, and it produces complete distributions for potency estimation error, rather than the single upper confidence value for potency produced by the EPA method (Bogen 1996). Our application of the MCPA method to the above-specified dose-response input data was carried out using a version of the program GL0BAL79 used for the analysis of dichotomous tumor response data (Crump and Watson 1979) which was modified to generate complete Monte Carlo distributions of site-specific as well as composite tumorigenic potency based on that data (Bogen 1986). Tiroe-to-tumor data were not used in our analysis of carcinogenic potency, although it would be possible to do so in the context of our analytical frame work using a time-dependent multistage model (Crump and Kowe 1934). EPA potency assessments have occasionally used time-to-tumor data with such a model when these data are available and when early mortality in a bioassay is prevalent to the extent that it may lead to distorted estimates of potency. Potency values thus derived tend to yield slightly greater values for potency than are derived using a multistage model that does not incorporate time-totumor information. For example, for compounds considered herein that are addressed by EPA health assessment documents, upper confidence limit potency values derived using time-to-tumor information are higher than those derived without this information by a factor of approximately 2 or less. How ever. the incorporation of time-to-tumor information into potency assessment requires several additional assumptions, such as the selection of an appropri ate exponent of time (which corresponds to an assumed number of stages in the multistage carcinogenic process) to use in the more complicated time-to-tumor model (Crump and Howe 1934). This introduce yet additional sources of uncer tainty into the analysis. Since the time-dependent and time-independent models yield similar potency estimates in the cases we consider for which a comparison was undertaken by EPA in its health assessment documents, we B & S 152061 o . ( `l have relied oniy on the time-independent multistage model for our analysis. Depending on the nature of a particular data set. the question may arise regarding how or whether to combine experimental incidence data for each significant tumor type observed in a given bioassay into data amenable to a quantitative assessment of increased composite risk, where here the term "composite" is used to refer to the potential or actual occurrence of any one or more types of tumor from among a prespecifled set of types. UFA has used a tumor counting procedure that consequently has become widely applied in the context of environmental carcinogen risk assessment. According to EPA, if data exist for two or more significant tumor types in the same study, the number of animals with at feast on* of these types is used as Incidence data for quantita tive assessment of composite risk when bioassay data must be relied on for this purpose (Anderson at of. 1983. EFA 1984a). This procedure has been criticized in that it may lead to results which are inconsistent with the underlying tumor incidence data used for a given potency assessment, and an alternative pro cedure. "composite potency analysis." is available which always yields con sistent potency estimates based on tumor incidence data segregated by tumor type (Bogen 1986). We have made use of composite potency analysis in the con text of our assessment of VCL carcinogenic potency, in which case 3 different tumor types were observed to occur with significantly increased incidence in rats. 2.2.3. Inter-Species Dose-Equivalence Extrapolation Equivalent doses between species may be calculated on the basis of dose per body weight or dose per body surface area. At present it is not known which inter-species dose extrapolation assumption better reflects reality in the context of extrapolating tumor response data in animal* to anticipated response in humans, and existing data do not rule out either approach (Hogan o o> - 13 - C and Hoel 1932). When data from a bioassay using mice. e.g.. are used for dose-response extrapolation, the choice of which inter-species dose extrapola tion method to use alters the resulting potency calculation by a factor o: more than 10. To provide and objective approach to the issue of inter-species dose extrapolation, we used a Monte Carlo approach to combine the potency distri butions based on the body weight and surface area methods, under the assump tion that each method is equally likely to reflect reality. 2.2. Methods tc Assumptions Regarding Risk Calculations To calculate approximate increased low-dose risk to BKK-vieinity residents, calculated excess doses in mg/kg/day for each of the compounds VCL, VDCL, DCE, BNZ and CLFM at each station were multiplied by the factor x 4r-x 0.S0 x 0.50 = 0.015625 in accordance with the assumptions we made regarding exposure duration, con centration dilution and absorption. These excess doses were then multiplied by the corresponding calculated MCPA potency distributions to yield approximate compound-specific risk distributions for each of the stations A. B, D, and F. in accordance with the approximate linearity of the multistage dose-response model at very low doses. The latter station-specific risk distributions were then summed, using a Monte Carlo procedure, to yield distributions of total increased risk due to all 5 compounds for each station, under the assumption that the carcinogenic potency of the mixture of compounds is in all cases equal to the simple sum of the individual compound-specific potencies. That is. we assumed that there is neither positive nor negative synergism among the carci nogenic potencies of the mixture of compounds considered. An overall BKK-vicinity risk distribution was then derived by taking a weighted average of the 4 calculated station-specific risk distributions, again using a Monte Carlo procedure, where the station-specific weights were all assumed to be equal (i.e.. all equal to 0.25, resulting in a simple average of the 4 distributions). Finally, from this average distribution of total increased risk, the median value (i.e., the 50th percentile value) was selected to represent a risk value which is as likely as not to overestimate the true level of average increased individual risk which BKK-vicinity residents have incurred over the 7-year period of interest, conditional on the set of assumptions we made in our risk analysis. 3. Risk Analysis Results Our calculated MCPA potency distributions for each of the compounds VCL. VDCL. DCS. BNZ and CLFM (as well as for the compounds PCE and TCE) are given in Appendix 3. Application of the methods described above using these potency distributions yielded the station-specific distributions of increased risk given in Appendix 3, and the corresponding overall distribution of increased risk is also given in Appendix 3. From the latter distribution, we select the 50th percentile value equal to 1.5 x 10"*, or approximately one chance in a million, as our best estimate of increased lifetime cancer risk for the average individual due to residence in the vicinity of the BKK landfill for the 7-year period of interest. Assuming a population of 7700 exposed individuals in the BKK landfill vicinity, this results in a corresponding predicted population risk of about 0.01 cases. 4. Discussion Our calculation indicates that it is highly unlikely that even a single case of cancer would arise from the described BKK landfill exposure scenario. This result is consistent with the DHS report which suggested that 50 x 10~* represents a "maximum risk" and that "the true excess risk of cancer is prob ably lower" (DHS 1983. p. 12). Other various assumptions that could have led to a lower result were not included in our analysis. Such alternative assumptions include factors to take into account (l) seasonal adjustment of concentration data; (2) the possibility that the reported ambient concentration differences are due to chance such that the actual TVTA concentrations at the landfill and at the comparison stations are equal and therefore the increased cancer risk is 0; (3) the possibility that the effective dilution factor due to atmospheric mixing might be much greater than the factor of 2 assumed for the average individual in the BIOC residential population; or (4) the possibility that perhaps Less than 50J5 of VDCL inhaled by humans will be metabolized even at low doses, in accordance with our analysis in Section 2.2.1*4 of data in EPA (1985b) relied on for VDCL potency assessment. We did investigate, however, the effect of using alternative assumptions regarding (1) the carcinogenicity of PCE and TCE and (2) the relative population density in BKK-vicinity areas influenced by Stations A, B. D and F. The inclusion of PCE and TCE potencies into our risk analysis, corresponding with a presump tion that these compounds are human carcinogens at low doses analogous to the other compounds VCL, VDCL, DCE, BNZ and- CLFM, results in an increase in our "best" estimate of increased individual risk from 1.5 x lQ- to 2.2 x 10_#, that is. an increase by a factor, of only 1.47. This result highlights the fact that increased risk in our analysis is primarily due to the impact of VDCL's carcino genic potency, which was calculated to be greater than that of the other com pounds. In the context of our calculation of overall increased risk using a weighted average of station-specific risks, the effect of changing the station weights from (.25..25..25..2S) to (.25..40..15..20) for Stations A. B. D and F. respectively, was negligible. R&S 152065 cc - 16 - To put these risks further into perspective it must be understood that a 1 x 10"* Lifetime mortality risk is roughly equivalent to 19 minutes of life expec tancy. or put another way, equal to the added risk of death that is incurred by driving a car 100 miles, by riding a bicycle 10 miles, by traveling for 6 minutes by canoe or by smoking 1 or 2 cigarettes (cf. Crouch and Wilson 1952). The latter risk, smoking 1-2 cigarettes, is approximately equivalent in cancer risk to living for two weeks in Los Angeles as a result of air pollution (cf. Ames 1933). Residents living in the vicinity of the BKK landfill therefore experience only a negligible increased cancer risk, similar to that now being used by the U.S. Food and Drug Administration as a benchmark of insignificant health risk requiring no regulatory action (FDA 1935). At very low doses, individual cancer risk becomes approximately equal to carcinogenic potency multiplied by dose, according to the cancer risk extrapo lation model we have used in thi* analysis. Using the published EPA ("95/1 upper confidence limit") potency values, relation allows us to make certain com-, p&risons of estimated excess individual risk associated with different exposure situations. Note that such risk values are only estimates that contain a great deal of uncertainty, and only a small part of this uncertainty is meant to be addressed by EFA's use of "upper confidence limit" risk estimates: see, e.g.. Anderson ef al. (1933). Cothern ef ai. (1934) and Bogen (1936). Nevertheless, such risk estimates are useful for comparative purposes, as we have under taken here. Firstly, we calculated the excess individual risk due to exposures (15 hours per day) at an average BKK residence (see Tables 2.1 and 2.3). We then com pared this risk value of 2.4 x 10" with that associated with other typical expo sures to some of the compounds listed in Table 2.1 and exposure to other t "everyday" carcinogens such as aflatoxin B,. which is present in all peanut R&S152066 t - 17 - ( butter at an average of 2 ppb and which is regulated at 20 ppb (Table 2.4). One peanut butter sandw,Ch per day works out to be at least 10 times worse than residence near BKK. which is similar in risk to drinking ordinary L\S. tap water and much less risky than taking a daUy hot tub. This increased individual risk value of 2.-V x io** is also absolutely minimal when compared to the risk incurred by someone working in a dry cleaning shop or in a plant manufactur ing vinylidene chloride (Table 2.4). We therefore conclude that exposure of residents to the compounds and ambient concentrations listed in Table 2.1 poses a minimal, negligible cancer risk--a risk that is highly unlikely to result in even a single excess cancer case over the lifetime of the exposed 3KX residen tial population. R&S152067 REFERENCES Ames, B,, 1983, "Dietary carcinogens and anticarcinogens," Science, voi, 221. pp. 1256-1264. Anderson. E. L., and the Carcinogen Assessment Group of the U.S. Environmen tal Protection Agency, 1983. "Quantitative approaches in use to assess cancer risk." Risk Analysis. voL 3, no. 4, pp. 277-295. Bogen. K.T., 1986. Uncertainty in Environmental Health Risk Assessment: A Framework for Analysis and an Application to a Chronic Exposure Situa tion Involving a Chemical Carcinogen. Dissertation. School of Public Health. University of California at Berkeley. Cothern. C.R., W.A. Coniglio. and W.L. Marcus, 1984, "Techniques for the Assess ment of Carcinogenic Risk to the U.S. Population Due to Exposure from Selected Volatile Organic Compounds from Drinking Water Via the Inges tion. Inhalation and Dermal Routes." U.S. Environmental Protection Agen cy. Office of Drinking Water. EPA 570/9-85*001 (1 May 1934), NTIS Report No. PB84-213941. Washington D.C. Crouch. E.A.C. and R. Wilson. 1982. Risk/Benefit Analysis. Ballinger, Cambridge MA. pp. 185-193. Crump. K.S. and W.W. Watson. 1979, "GLQBAL79: A Fortran Program to Extrapo late Dichotomous Animal Carcinogenicity Data to Low Doses." National In stitute of Environmental Health Sciences. Contract No. l-ES-2123 (1979). Crump.-ICS. and R.B. Howe, 1984, "The multistage model with a time-dependent dose pattern: applications to carcinogenic risk assessment," Risk Analysis, voL 4, no. 3, pp. 163-176. DKS, California Department of Health Services, Toxic Substances Control Divi sion; California Air Resources Board. Kaagen-Smit Laboratory Division; and South Coast Air Quality Management District, 1983, "Ambient Air Monitor ing and Health Risk Assessment for Suspect Human Carcinogens Around the BKK Landfill in West Covina," (March 1983). EPA, U.S. Environmental Protection Agency, 1994a. "Proposed Guidelines for Carcinogen Risk Assessment." Federal Register, voL. 49. no. 227 (23 Nov. 1984), pp. 46294-46301. EPA. U.S. Environmental Protection Agency. Office of Research and Develop ment. Office of Health and Environmental Assessment, Evironmental Cri teria and Assessment Office, 1984b, "Health Assessment Document for Tetrachloroethylene (Perchloroethylene),*' (EPA/600/8-S2/005F Final Re port. July 1985), Research Triangle Park. NC 27711. EPA, U.S. Environmental Protection Agency, Office of Research and Develop ment. Office of Health and Environmental Assessment. Evironmental Cri teria and Assessment Office. 19B5a, "Health Assessment Document for Tri chloroethylene," (EPA/600/B-92/006F Final Report. July 1985; NTIS # PB65-24969B). Research Triangle Park. NC 27711. EPA. U.S. Environmental Protection Agency, Office of Research and Develop ment. Office of Health and Environmental Assessment. Evironmental Cri teria and Assessment Office, 1985b, "Health Assessment Document for Vinylidene Chloride," (EPA/800/9-33/Q31F, August 1985), Research Triangle Park, NC 27711. ' Cl * (c EPA. U.S. Environmental Protection Agency, Office of Research and Develop ment. Office of Health and Environmental Assessment. Evironmental Cri teria and Assessment Office, 1935c. "Health Assessment Document for 1.2Dichloroethane (Ethylene Chloride)," (EPA/600/8-94/006F Final Report. Sept. 1935), Research Triangle Park. NC 27711. EPA, U.S. Environmental Protection Agency. Office of Research and Develop ment. Office of Health and Environmental Assessment, Evironmental Cri teria and Assessment Office, 19B5d, "Health Assessment Document for Chloroform." (EPA/600/9-34/004F Final Report, Sept. 1935). Research Tri angle Park, NC 27711. FDA. U.S. Food and Drug Administration. 1985. "Proposed ban on the use of methylene chloride as an ingredient of aerosol cosmetic products." /federal Register. voL 50. no. (18 Dec. 1985), pp. 51551-51559. Fox, T.R. and P.G. Watanabe. 1985, "Detection of a cellular oncogene in spon taneous liver tumors of B6C3F1 mice," Science, voL 22S. pp. 596-597. Gehring, P.J.. P.G. Watanabe. and C.N. Park. 1978, "Resolution of dose-response toxicity data for chemicals requiring metabolic activation: Example--Vinyl Chloride." Toxical, Appl. Pharmacol., voL 44, pp. 581-591. Gehring, P.J.. P.G. Watanabe. and C.N. Park. 1979, "Risk of angiosarcoma in workers exposed to vinyl chloride as predicted from studies in rats." Taxicol. Appl. Pharmacol., voL 49. pp. 15-21. Hogan, M.D. and D.G. Hoel. 1982, "Extrapolation to man." in principles and Methods of Toxicology, ed. A.W. Hayes, Raven Press. New York. pp. 711-731. Maltani. C. and G. LeFemine, 1975, "Carcinogenicity assays of vinyl chloride: current results." Ann. N.Y. Acad. Sci., voL 24S, pp. 195-224. Maltoni. C,, 1983, "Myths and facts in the history of benzene carcinogenicity,". in Advances in Envinmmentxt Toxicology, Vol. TV: Carcinogenicity and Tox icity of Benzene, ed. M.A. Mehlman, Princeton Scientific Publishers Inc., Princeton, pp. 1-13. Mirsalis. J.C., C.K- Tyson. E.N. Loh, K.L. Steinmetz, J.P. Bakke, C.M. Hamilton, D.K. Spak. and J.W.'Spalding. 1985. "Induction of hepatic cell proliferation and unscheduled DNA synthesis in mouse hepatocytes following in vivo treat ment." Cixreinopenesii, voL 6, pp. 1521-1524. NAS, National Academy of Sciences. Committee on the Institutional Means for Assessment of Risks to Public Health. 1983. Bisk Assessment in the Federal Government: Managing the process. National Academy Press, Washington. D.C., pp. 36-37. NTP. National Toxicology Program. 1985, "NTP Technical Report on the Toxicol ogy and Carcinogenesis Studies of Tetrachloroetbylene (Perchioroethylene) (Cas No. 127-1B-4) In F344/N Rats and 36C3F1 Mice (Inha lation Studies)." Draft Report dated 9/85 (NTP TR 311, NIK Publication No. 35-2567). Research TriangLe Park. NC 27703. R&S 152069 c Table 2.1 Increased Exposure Above Measured Control Levels for Air contaminants Measured at 4 BKK-Vicinity Monitoring Stations Increased Exposure in mg/kg/day (assuming 20 m3/70 kg/day intake) At Monitoring station: Compound vinyl Chloride Perchloroethylene Trichloroethylene Vinylidene Chloride 1,2-Dichloroethane Benzene Chloroform A B0 P Mean .0034 .0019 .0010 .0011 .0019 .0011 .0018 .0011 .00087 .0015. .0016 .0021 .00074 .00062 .0014 .0014 .00091 .00091 .00007 .00056 o *o .0011 .0011 .00017 .00023 -.00055 -.00029 .0016 ' .0013 .0015 .0007 .0012 .0006 .00009 R&S 152070 o o* TAELE 2.2 POTENCY ANALYSIS INPUT KEY: LINE i * TITLE LINE HZ * ANIMALS PEP OCSE CROUP (SURVIVING UNTIL AFTER THE OCCURRENCE OF THE iST TuMCR IN THE EXPERIMENT) LINE *3 TUMOR-BEARING ANIMALS PEf COSE GROUP LINE 9 f EQUIVALENT APPLIED DOSES FCR EACH DOSE GROUP (IN MG/KG/CAY) 2. c VCL HALTCM75 SPR-DAw RATS FEMALE .3SKG HEAD KC/KG/C 56*59,59,59,59,6C*61 0 ,0,0,9 ,2 *7* 16 0 .0,9.225 ,13.92,19.52*23.76,30.90,31.57 ZYMBAL GLANC V CL MALTCNI75 SPR-CAH RATS FEMALE .3*KG HEAC KG/KG/C , , , , ,56, 59,59.59,59.6C.61 0 1 6 9 6 9,5 0.0,9.225,13.92,19.52,23.76,30.90,31.57 nefhrqelastohas VCL MALTOHI75 SPR-OAH RaTS FEMALE .35KG HEAD MG/KG/C 56,59,59,59,59,60.61 C ,1,9,7,3 ,13,9 C.0,9.225 ,13.92,19.52,23.7o,30.90,3i.57 LIVER ANGIOSARCOMAS cCL MALT0N175 SPR-Dah RaTS FEMALE .35nG HEAC MG/KC/C 56*59,59*59,55,60,61 6 ,1C.lo.22.32.31.36 0.0,9.225 ,13.92,19.52,23.76,30.90,31.57 COMPOSITE BENZENE MALT0NI63 5-C RATS FEMALE .3CKG HEAC MG/KC/C 3o0,2,3,e0.32 0*0*16*07*dQ36 ZYM6AL CLANG VlNYLlDENE CL MALTUN165 SR MICE .035KG MEAD ML/KG/D KIDNEY AOEnCSaRC. 126.25.115 0 ,0,2E 0 .0,0.9627,2.957 CCE NCI7e 0-M RATS MALE 9C,fc6,27 0 ,9,7 0 .0,23.1t ,92.75 .5KG HEAC KC/KG/C HEMANGIQSARCOMAS ,DCE NCI76 3&C3F1 1 . ,97,96 1 6,12 C.0,99.35 ,57.7G MICE macE .035KG HEAD MG/KG sC HEPATOCARC INCHAS 9^ R & S 152071 ^KHLOKCFORh. NCI 76 BtaC3Fl MICE MALE. 03SKG HEAD MG/KG/L w~]Kr*85.0A,4a5 =0 .0.79.A2.159.A HEPaTCCARCINQhaS CHLCRCFCRM NCI7t> etC3Fl MICE FEMALE.02BKG HEAD MG7KG/C 20.A5.A1 0.36.39 C .0,137.0 .27*.5 HEFaTCCARCINGMaS PCE NCI77 20.A6.A5 SbCEFl MICE, 2 .32.2 7 0 .0.118.66.163.39 MALES HALO (MC/KG/CAT) via SAME LIVER PCE NCI77 2C.A8.A5 66C3F1 MICE. FEMALES 0.19.19 .0.97.71S.1A2.76 HALO (HC/KG/CAT) VIA SAME LIVER PCE NTP85 A 7.A6.50 16.31.AO E6C3F1 MICE: 0 .0.119.96,203.02 MalE HALC MG/KG/OAV VIA SAME.HEP AC/CARC PCE KTP85 39.A0.A6 E6C3F1 MICE: FEMALE HALC MG/KG/DA1 VIA SAME, KEP CARC \3.2b ,12 A .79.209Ifc9 TCE MP82 A 8,50 8 .3C C .0 ,675 .830 E6C3F1 MICE: -MALE HALC MG/KG/DAI VIA SAME HEP CARC TCE NTF62 A 6 . A9 2 .13 0.0.680.AC9 86C3F1 MICE: FEMALE HALC HG/KG/OAV VIA SAME HEP CARC ISE*N517e EtC3F1 "ICE: 2C.5C.A8 1 .26.31 0-0.AAA.595.3A5.5A5 MALES HALO MG/KG/OAt VIA SAME HEF CARC NC17c SfcC3Fl MICE: 20.50. A7 0.A.11 C.0.337.779,655.510 FEMALES HALO MG/KG/CAT VIA SAME hP CARC c c R&S152072 ( APPENDIX THREE RISE ANALYSIS OUTPUT c c CL - L-U :a;S .-^iiALE r\G Tumor i gen <_ Potency Distribution Calculated Assuming Equipctent Doses Can Ee Extrapolated Between Species cn a til ,nq per Eocy Weight lEw) Basis cr 12) mg per Surf-ce Area tSA) Easis Percentile 0.430C 1.000C 2.000C 3.0000 <1.0000 5.0C0C 6.C0QG 7.000C 8.C00C 9.0000 10.00CC U.OOOC 12.0000 13.0C0G U.OOOC 15.0000 16.COCO 17.0000 1E.0CCC 19.QC0C 20.0000 21.000C 22.0C0C 23.000C 24.0C0C Z5.0C0C 26.000C "27.C00C 2B.0C0C 29.0000 30.000C 31.0C0C 32.0000 33.000c 34.0000 35.0C0C 36.GOOC 37.0000 3e.oooc 39.0C0C 40.0CGC 41.0CGC 42.00GC 43.0000 44.G00C 45.G0GC 46.000C 47.0CCG 48.GC0G 49.GG0C 50.CO0G 55 91.0000 Potency (i/[mg/k,g/aay J) Calculated using Extrapolat ion Assumption: Bw SA Percentile 0. 0.0005726795 0.0012990717 0.CC1615to92 0.C0212bo2e0 0.0023970178 0.0026284026 0.0028122789 0.0029672480 0.CC311S1H13 0.0032536136 0.0033952545 0.CC352B0201 0.0036366538 0.0037545366 C.CC38785900 0.0039749783 0.00^0688273 0.0041523&78 0.0042639095 0.0043675330 0.0044624414 0.C045H04690 0.004o295142 C.0C471175G8 0.0047964691 C.0048768963 0.0049669673 0.0050474182 0.0051244469 0.0051969453 C .0052697374 0.0053448596 0.0054183519 G.C054S30536 G.CC55457177 0.0056090541 0.0056853541 C.005 7550259 0.0C5&230604 0.0058844727 0.0059575361 0.0060177930 0.0060732237 0.0Ctl279945 C.0061864941 0.00625 44 325 0.C0O3161105 0.0063730385 0.0064345961 0.CC64955465 0.0065528918 ** *. 6 1 C 1 40/, 0. 0 .0033490527 0.0076017021 0.0106181065 0.0124365935 0.0140225347 0 .0153710032 0.0164463203 0.0173525847 0.0 1 62174 705 0*0190272629 0 .0198555849 0.02 06320 025 0.0212769942 0.0219566803 0.0226821490 0.0232456320 0.0237546641 0.0242832135 0.0249355137 0.0255418 CIO 0.02 609 65358 0.0265528448 0 .0270735645 0.0275545549 0.0280616 395 0.G285202E42 0.029047Q235 0.C29E175C35 0.0299679711 0 .030391944c 0 .0308176354 0-0312569551 0 .0316667381 0 .0320651159 0-0324315EC1 0.0328066535 0.0332481787 0.0336556211 0.0340534896 0.0344126336 0.0348402150 0.0351922959 0.0355203152 0 .0356367562 0 .0361766645 0 .0365764648 0.03e93otit6C 0 .0372697860 0 .0376297757 0.0379862152 0.03,3215733 0.4300 1.0C0C 2.0CCC 3.0CCCJ 4.0C0C 5.0CCC 6.0COC 7.0C0C 8.0C0C 9.0CCC 10.0COC ll.GCCC 12.0C0C 13.0CCC 14.0CCC 15.0CCC 16.0C0C 17.0C0C le.occc 19 .0000 20.0CCC 21.0CCC 22.0CCC 23.0CC0 24.0CCC 25.0C0C 26.0C0C 27.0C0C 28.0CCC 29.0C0C 30.0000 31.0C3C 32.0CC0 33.OC0C 34.0C0C 35.0CQC 36.0CSC 37.0CQC 36.0CCC 39.0CCC 4C.0CCC 41.0CCC 42.0CCC 43.0CCC 44.0CCC 45.DCGC 46.0COC 47.0CCC 48.0CCC 49.0CGC 5O.OC0C 51.0CCC **' > R&S 152074  3 > u^O c Sej.oooc 57.QC0C 56.000C 55.000G 60.0000 tl.CCOC 62.OCOC 63.OCOC 04.0000 65.0000 tt.OOOC 67.Q0CC te.oooc 69.OCOC 7C.0C0C 71*0000 72.000C 73.000C 74.OCOC 75. OCOC 76.0C0C 77.0C0C 78.000C 79.0000 eo.oooc Sl.COOC 82.0C0C 3.0000 E4.000C E5.0C0C 66.OCOC 7.0000 66.0C0C 9.0000 9C.CC0C 91.00CC 92.0000 93.0CCC 94. OCOC 95.000C 96.000 C 97.0000 9e.ococ 99.OCOC jwi; / 5 7 2 5 *' .CG66528769 0'.C0tj9ie2f69 0.0069725960 Q.G07C274523 C *0070795454 0.CC71384124 0.0071989144 0.CC7252940C 0.0075079383 0.0073671667 0.CC74252975 0.CC74962992 C.CC75497241 0.0076115336 0.0076629536 0.C077161331 0.0077770394 0.0078272959 0.C07S862319 0.0079470677 0.CC8Q047920 0.CC807CO635 O.CC8132oi42 C.0082012340 C.CC82558179 O.CG6327od53 C.CCE396221S 0.0084746592 0.CCE5414629 0.0086164356 0.0086653262 0.0067648258 0.0088466390 0.0089489324 0.0090373392 0.CC91302823 C.0092368033 0.0093518551 0.0094750915 C.CC9&185394 O.C097683055 C.CC99&60312 0.0102364104 0.0106925238 ' G .3597=0*1 <t5o 0.040C758962 0 .04045818^7 0 .0407760216 0 .04iQ9fc62l4 0.0414014 e45 0.0417457223 0.0420995392 0.0424154648 0.0427371152 0.0430834652 0 .0434234366 0.0438386574 0 .0441510901 0.0445125350 0.04iei32104 0.0451362431 0.0454804 376 0.0457743406 0.0461190C08 0.0464747697 0 .0468123443 0.C471975t54 0.04 75598336 O.C47961145e 0.0432603546 0.0467006361 0.0491131395 0 .0495601483 0.C499S06195 0.0503895344 0.0507950706 0.0512570515 0.0517357523 0.0523337163 0.0528536476 0.0533942580 0.C540171973 0.0546900257 0.0554107167 0.0562496C36 0.0572424C47 0.0534105612 0.05?e62937e O.C625303C90 C-- -- U c u C -6 .OCOC 37.0CCC 58. OCOC 59.OCOC cO.OCOC tl.OCCC 62. OCOC 63.OCOC 6*. OCOC 65.OCOC 66.OCOC 67.0CCC 6S.0CCC 69.0CCC 70.0CCC 71.OCOC 72.0CQC 73.0CCC 74 .OCOC 75.OCOC 76.0CCC 77.0CCC 78.0CCC 79.OCOC 60.0CCC 81.0CCC 62.0CGC 83.0CCC e4.occc C5.0CCC 6.OCOC 87.0CCC ee.occc C9.0CCC 90.QCCC 91.0CCC 92.OCOC 93.OCOC 94 .OCOC 95.OCOC 96.OCOC 97.OCOC 9.OCOC 99.OCOC R&S152075 PCE PCE N TFS 5 NTF65 1 BbC3 EoC3Fi nICE : MICE: i -L;mG/nC male HALC MCyKC/DAI female HALC HG/XG/DAI ; IA VIA -i:. same. ^vef. SAME,HEP AO/CARC SAME, hEP CARC Tumorigen ic Potency Distribution Calculatec Assuming Equipotent Ocses Can e Extrapolated Between Species on a 11) mg per 6ocy Height tSW> Basis cr (2) mg per Surface Area (SAJ Easis 'ercenti le 23.520C 24.0000 25.0000 26.000C 27.000C 26.0C0C 29.000C 30.0000 31.Q00C 32.0000 33.C00C 34.0000 35.0000 36.0000 37.0000 36.0000 39.0C00 40.00GC 41.Q0QC 42.0C0C 43.0000 "'44.0000 45.000C 4b.0000 47.000C 48.C00C 49.0000 50.0000 5X.00CC 52.0000 53.0000 54.0000 55.Q00C 56.0000 57.0000 56.0000 59.300C to.ocoo 6l000C b2.000C 63.CC0C 64.000C o5.QOOC 66.0000 C7.C00G 68.C000 69.0000 70.0000 71.0000 72.0000 73. oner Potency (l/[mg/kg/aay1 ) Calculated Using Extrapolation Assumption: BW SA Percent lie 0. 0.0000631399 0.0002477595 0.0004065095 0.0005406287 0.0006775336 0.0008084442 O.COC9508O39 0.0010622996 0.C012121321 0.0013783769 0.C015607907 0.0017147622 0.0018365651 0.0019815555 0.C021057397 0.C022612270 0.C0234471CS 0.0024843295 0.C026001376 0.0026963133 0.0026273263 0.0029609974 C.CG20636b03 O.CC32178S43 0.C033G36264 0.0033742981 0.C0344O5054 0.003540153*1 0.0036381371 0.CC36876083 0.0037636900 0.CC36175124 0.0039036532 0.0039779469 0.0040559196 0.C0411B9243 0.0041798120 0.004249751b O.QC43027191 0.0043729548 0.0044210218 0.0044639523 0.0045630060 0.CC4O134 321 0.CG47130641 0.C047519626 0.C04E404224 0.0C49026Jfi2 Q.0C49709054 n ,, nnemtnoKi 0. 0.0008419139 0.0032905159 0.0053327973 0.0071042343 0.0089232866 0.0105216913 0.C124C29778 0.014C911490 0.0157920271 0.0182200354 0.0207534954 0.0223cl4757 0 .0239088777 0.0262096580 0.0275176186 0.0296708345 0.0310361241 0.0326C732B1 0.0346589722 0.0360331582 0.0368654616 0.0390260671 0.0408C94414 0.0419077E36 0.0438546464 0 .0451851636 0.0462058075 0.0471365531 0 .0481932C89 0.0497919470 0 .0509260669. 0.0517350100 0.0527275520 0.0537138171 0.0543200411 0.0555971563 0.0560675710 0.05c9670C14 0.0578635931 0.0585039258 0 .0596585 C87 0.0602021478 0.0613929220 0.062C1O4 797 0.0625100061 0.0634471178 0.0644137189 0.0649261536 0 .066317804a 23.520C 24.0C0C 25.0C0C 26.0CCC 27.0C0C 28.0CCC 29.0CQC 30.0C0C 31.0C0C 32.0CCQ 33.0000 34.0C0C 35.0C0C 36.0C0C 37.0C0C 36.0C00 39.0C00 40.0000 41.0C0C 42.0CCC 43.0C0C 44.QCCC 45.0C0C 46.000C 47.0C0C 46.0C0C 49.0CCC 50.0COC 51.0C0C 52.0C0C 53.0C0C 54.0C0C 55.0CCC 56.0CCC 57.0C00 56.0C00 59.0C0C eO.OCOC 61.0C0C 62.0CC0 63.0CCC 64.0CCC 65.0000 66.0 CO C 67.0C0C tB.OCCC 69.QC0C 70.0CCC 71.0C0C 72.0C0C 77 nrrp R&S 152076 4 \J * W WWW 77.0000 78.0C0C 79.0000 eo.oooc 81.0000 82.000C 63.0C0G 8*.0000 65.000C 86.0CGC 87.0000 ae.oooc 89.0000 90.000C 91.000C 92.QC0C 93.000C 94.Q00C 9S.0C0C 98.000C 97.0000 98.000C 99.0000 G.CC5221550 0.CQ531 .083 C.0053876846 C.CG54476908 0.0055350373 0.0058042088 0.0056812912 0.0057923449 0.0058550616 0.0059278943 0.0060320524 0.0081395695 0.0062557189 0.C063808969 0.0064814021 0.0066168713 C.0067779957 C.0068894438 0.0070212791 0.0072206082 0.C0736812B5 0.C075660926 0.0078990255 C.0084332814 J .0659715^45 0 .0696 585774 0.0707354471 0 .0712223C70 0.0723741t51 0.0732380450 0.0739637436 0.0750207230 0.0761620775 0.0772702247 0 .0783423260 0.0797456056 0.0812C87208 0.0624906453 0 .0640217695 0 .08534067E7 0.0667500380 0.0888896659 0*0911299139 0.0928635597 0.0958132222 0.0984 798148 0.1026449278 0.1C77E51206 76.5 0'" 77 aOCl 78.0C0C 79.0C00 eo.ococ ei.ococ 82.0CCC 3.0000 84.0000 e5.occc et.occc 67.0000 be.ococ 89.0C0C 90.0C0C 91.0CCC 92.0C0C 93.0C0C 94.0000 95.0000 96.0C0C 97.0C0C 98.0CCC 99.0CCC R&S152077 fCS TCE NCI7t NCI76 ' -1 :-''r--'Ai_ t/0.`i : = eCJ."l< ct: :iaLS hal0 PG/kG/LaY' a SAf-t 3toC3Fl ,.4C: FEMALES HALC HG/KG/CAT 1A SAk ` t . r ^ r\ C HtP CAkC HEP CARC Tuiror i genic Potency Distribution Calculatec Ass urn in g Equipctent Doses Can Be Extrapc 1ateo Between Species on a ill mg per Bocy Height (Bk) Basis or l2J mg per Surface Area (SA) Basi 5 Percentile Potency ll/tmg/kg/cay] ) Calculated Using Extrapolation Assumption: 6H SA Percert ile 11.600C 12.000C 13.CC0G 14.0000 15.0000 16.0000 17.0000 IB.OCOC 19.QC0C 20.000C 21.000C 22.0000 23.000C I4.000C 25.00CC 26.0C0G 27.0000 28.0000 29.0Q0C 30.0000 31.000C 32.0000 33.0C0G 34.000C 35.OCC0 36.00CG 27.000C 38.0000 39.0000 40.0000 41.0000 42.0000 43.000C 44.0000 45.0000 46.C00C 47.000C 46.0000 49.0000 50.0000 51.C00C 52.0Q0C 53.0000 54.0000 55.0000 56.0000 57.COCO 58.0000 59.0000 1CO.GCOC onA ^ 0. O.COOQ2SB716 0.CCG0531952 0.0G00735315 0.0000769660 0.0001185321 0.0001299646 0.0001623041 0.0C01717535 0.0001994221 0.0002066782 O.0C02111J95 0.0002317257 0.0002410785 0.0002555447 0.C002674929 C.C002729225 C.CC02864209 0.0002967948 0.0003045304 0.CC031245SS 0.0003162312 0.0CC3278O30 0.0003427067 0.0003502932 0.0003569786 0.C0C3671742 0.0003819009 0 .0003870664 0.0003929799 0.0004038969 0.00042033 70 0.0004319644 0.0004422651 0.0C04531117 O.COG4652110 C.OCOHfil7551 0.0005044929 0.CC05184426 0.CCC537U77 0.0005564941 0.0005792555 0.0006026781 O0C0c419369 0.0006660301 0.0006980940 C.0007303558 0.GGC7553491 0.00077 892 82 C.0GC8099292 0. 0.0C04C10B05 0.0004617567 0.0010205493 0.0010693242 0.0016247210 0.0016E74B71 0.0021598654 0.0022996233 0.0025246800 0.0027376411 0.002CE02C75 0.0029799310 0.0030773962 0.0033821E20 0.0034916122 0.0035558483 0.0037451424 0.0038907297 0.0040064 328 0.004C976494 0 .0041765 687 0.0043178336 0.0044134 ies 0.0044350601 0.004O192929 0.0048116501 0.CC48415521 0.0049207t99 0.0050728549 0.0052447676 0.0054401890 0 .0055211429 0.0057C66 500 0.0058406456 0.C0597917ol 0.0061627164 0.0063774111 0.00O5426946 0.0067672594 0 .CO70168427 0.00 73C4G7C5 0.00 75932685 0 .0080260732 0 .0083375992 0.0086673699 0.0089960 C33 0.0093287C15 0.009t4l7506 0.0099793402 A nf 4 11.6CG0 12.0C0C 13.0C0C 14.OCC0 15.OCC0 lt.OCOC 17.3CCC le.occc 19.0C0C 20.0C0C 21.0CQC 22.0CCC 23.0C0C 24.0CCC 25.0C0C 26.0C0C 27.0CCC 2.0CCC 29.0CCC 3O.OC0C 31.3CCC 32.0C0C 33.0CCC 34.0CCC 35.OC0C 36.0C0C 37.0CCC 36.0C0C 39.0CGC 40.0COC 41.0COC 42.OC0C 42.0CCC 44.OCOC 45.0C0C 46.OCOC 47.OCOC 48. OCOC 49.0CCC 50.0CCC 51.OCOC 52.OCOC 53.OCOC 54.OCOC 55.0CC0 5 .OCOC 57.3CCC 58.OCOC 59.0CCC oO.OCCC R&S 152078 62QOOG 63.0000 64.0000 65.000C tt.QOOC 67.OCOO 66.QC00 tS.QCOG 70.0000 71.000C 72.0000 73.OCOO 74.0Q0C 75.0000 76.0000 77.CCCC 76.000C 79.000C 6C.0C0C 61.0000 82.0000 63.0000 64.0000 65.000C 66.000C 67.00CC Ee.ococ 69.000C 9C.OCOC 91.000C 92.000C 93.000C 94.000C 95.000C 56.OCOO S7.000C 96.0000 99.000C 0. COGtf 400H 0.0006792258 C.0009100983 0.CG0926O917 0.0009449993 0.0009639515 0.0009767214 C.CC09926786 0.0010138333 C.CC10469393 0.CC1054 7247 C.0010860262 0.0010860262 0.0011097321 G*0011232s46 0.001140e336 0.0C1160H31 0.C01171748O 0.0011930885 0.C012043S2G 0.0012199676 0.0012353265 0.0012502574 0.0012755778 C.0012912479 0.0013026590 0.0013261532 0.0C13389966 0.0013619312 0.0C13769770 0.C013963441 0.0014159299 O.CCl**4l5a35 C.0014610815 0.0015181559 0 *0015631253 0.0016321145 0.0017534167 0 .0105952565 Q-01Q'j503596 0.0llllo7CB6 0*0113679135 0.0116341598 0 .011820** 370 0.G120875696 0.0122434404 0.0126162264 0.0126998471 0.0130673681 0.0132064130 0.0135276621 0.0136578409 0.0139594963 0.0140514616 0.0143212499 0.0144456686 9.0146767264 0.0149525125 0.0152541241 0.0155025935 0.0156662275 0.0159120634 0.0160674529 0.0163902510 o.oib6i65269 0.0167716 797 0.0170479119 0.0172618143 0.0176176969 0.0179115627 0 .0 1 8164 9 76 7 0.0185676506 0.0190631678 0.0197C35675 0.0204428225 0.0217666433 t2.0l . >3.0 COC 64.QC0C 65.0C0C tfa.OCOC e7.OCOO C8.0 CGC C9.0CQC 70.0CCC 71.0C0C 72.0C0C 73.0COC 74.0CCC 75.0C0C 76.0C0C 77.QC0C 76.0COC 79.0 COC 60.0COC 61.0CCC 62.0CCC E3.0C0C 64.0COC 65.0CCC 66.0C0C 67.0C0C ee.ococ e9.0CCC 90.0 COC 91.0C0C 52.0C0C 53.0C0C 94 .0CCC 95.0C0C 56.0C0C 57.0CCC 56.0C0C 59.0C0C V IriTfL 12Ehc Cl 5 Sr. MICE C35KG liG/Ht/C K K f aCEnGC*.RC1NQma Tumorigenic Potency Distribution Calculatec Assuming Equipctent Ocses Can 6e Ext rape 1 a tec Between Species on a 11) mg per Bocy weicnt (EW) Basis or (2) mg per Surface Area iSA) easis Percentile 57.4000 58.GOOC 59.0000 fcO.OCOC 61.Q00C <s2.CQ00 63.GQ0C 64.0Q0C 65.0C0C 66.0000 67.0000 66.000C 69.0C0C 70.0C0C 71.0GOC 72.GCCC 73.0C0C 76.C00C 75.000C 76.0C0C 77.000C 76.C00C 79.0C0C 8C.0C0C 81.0C0G 62.G00C 83.000C 84.0COG 85.0C0C ee.OGOC 67.0C00 6B.C00G 9.0000 90.000C 91.000C 92 000 C 93.0C0C 94.0C0C 95.0COC 96.0C0C 57.0000 9e.00CC 59.C00C Potency (1/lmg/kg/day1) Calculated using Extrapolation Assumption: SA 0. 0.CO23508139 0.CC23508139 0*0023508X39 0*0023506139 0*0052523129 0.C052523129 0*0052523129 0.CC61231373 0.0061231073 0*0109638385 0*0109635385 0.0137751363 C.0137751363 0*0165575966 0*0193118080 0*0267377918 0.0403775983 0.0501255058 0*0532964957 0.0595352650 0.0626006722 0.0626006722 0.0656316665 0.0656318665 0.0686295033 0.C715944 767 0.0715944767 0.C745273232 0.0745273232 0.0774268177 C.0774288177 0.0794975162 0.0802996159 0.C831C80675 0.06333le445 0.0633316445 O.C9Q6eifi5o9 0.0964939337 C.1C66254709 0.1109157301 C.118E609372 0.1234383583 0. 0.0296163750 0.0296163750 0 .0296183750 0.0296163750 0.0661749293 0 .0661749393 0*0661749393 0.1023446545 0.1023 446 545 0.1381355971 0.1381355971 0 *1735557020 0 *1735557020 0.2086124716 0*2433133423 0.3116757572 0*5087254643 0.6315413U7 0.6715184450 0.7500967383 0 *7887184 C24 0 *7887184 C24 0.6269C9CC56 0 *8269090056 0 .8646768232 0.9020331502 0.902C231502 0.5389846921 0.9389846521 0.9755411744 0.9755411744 1.0016051531 1.0117108622 1.04 7095179fc 1 .04 99120951 1.0499120551 1.1447867155 1*2409447432 1.3459155560 1 .3974500895 1.4978053570 1.55522*5278 Percertile 57.4CCC 58.0C0C 5910CCC tC.OCOC 61.0C0C 62.0CCC 83.0C0C 64.0C0C 65.0C0C 66.0C0C t7.3C0C ee.ococ 69.0CCC 70-0CCC 71.0CCC 72.0C0C 73.0CCC 74.0CCC 75.0CCC 76.0CCC 77.0C0C 7e.occc 79.0CQC eo.ococ 61.0CCC 62.0C0C 63.0CCC 64.0CCC 65.0CCC 86.0C0C 87.0C0C ee.ococ 69.3CCC 90.0CQC 51.0C0C 92.0C0C 93.0CCC 54.OC0C 95.0CCC 96.0C0C S7.0CCC 96.0C0C 99.0C0C R&S 152080 J Tumor ' genc Potency Distribution Calculatec A S s um i n j Equipctent Doses Can Be Extrapolatee Between Spec ies on a l1) mq per Eoc> Weignt (Sw) Basis cr (2) mg per Surface Area ISA) fcas i s Percenti le 32.0550 33.000C 34.0CCC 35.0000 36.0000 37.0000 38.CQ0C 39.0000 40.0000 41.0C0C 42.0000 43.0QOC 44.GC0C 45.GGQC 46.0000 47.0000 4B.0C0C 49.0C0C 50.0000 51.0C0C 52.0C0C 53.0C0C 54.0C0C 55.0C0C 56.QC0C 57.000C 56.00CC 59.00C0 (jC.QQCC 61.000C 62.0000 63.000C 64.0000 65.00CC 66.0030 67.0000 66.000C 69.0000 70.0000 71.0G0C 72.0000 73.0000 74.0C0C 75.Q00C 76.0000 77.000C 78.0000 79.0000 eo.ococ E1.0C0C fai.ocoo 3.0000 Potency ll/tm g/Kg/cay 1J Calculated Using Extrapolation a ssunption: 6* SA Perce rtile C. 0.0001023053 0.0004158972 0*C0C62230fi 0.QC06052544 0.0010680376 0.0012650864 0.CC13524315 0.C01460S92B 0.0016244322 0.0016513089 0.CC20l7699e 0.CC20587973 C.0022667374 0.CC2395o372 C.0C25417392 0.0026377053 C.0027363470 C.CC2S409075 0.CC28641261 0.CC30001164 C.QC31o6335C 0.0033263465 0.0034470366 0.0035790491 0.00jd29.s9i 0.003754912b 0.0039007415 0.CC41051777 C.0041463746 0.0C427347el 0.0042826235 C.C043652970 0.0045969049 0.0047065211 0.0046733628 0.0050965096 0.005x347317 0.0052294573 0.0052772732 0.0056311530 0.0057513049 0.00579263 76 0.0059661344 C.0063385554 0.0064640131 0.0067303953 0.C0o6540093 0.0068751334 0.CC 7373 34 04 0.CC7447748G 0.0074609537 0. 0.0010927507 0 .0034300131 0.0C52C99419 ' 0.0067426893 0 .0 0 762 0 3 055 0.0101002697 0.0106902649 0.C126C90139 0.0142214093 0.0148719465 0 .0160176922 0.0172541905 0.0183555558 0.0192078575 0.0205113776 0.0220622C46 0.0222374 797 0 .0227661040 0.0244304445 0.0251968tfi9 0.0264859651 0 .0266618678 0.C2720CSC87 0 .0280365832 3 .0291268602 0.02 96260286 0.03000 76 716 0.0307655465 0.0314085409 0.0326598287 0.0329465419 0.0335101448 0 .0340721*56 0.0351662982 C .0355 613206 0.0356993226 0.03o3942C12 0 .0382859968 0.0366370271 0.0387365334 0.0390550457 0.0395 76C53t 0.0404470563 0 .0413730331 0 .0415524e06 0.042E625122 0.0434967284 0.044339999c 0.0445330563 0 .04 50259484 0 .0455429740 32.055C 33.0CC0 34.0CCC 35.0CCC 36.0CCC 37.000C 36.0CCC 39.0C0C 40.0CCC 41.0CCC 42.0CGC 43.0CCC 44.0CCC 45.0CCC 46.0CCC 47.0CCC 48.0COC 49.0CCC 50.0CCC 51.3C0C 52.0CCC 53.0CCC 54.0CCC 55.0CCC 56.0C0C 57.OC0C 58.000C 59.0C0C 6C.0CCC 61.0CCC 62.OCOO 63.0000 64.OCOO 65.0CCC 6 6 0 CC C 67.0CCC 68. OCOO 69.0C0C 70.0CCC 71.0CCC 72.QCCC 73.0CCC 74.0000 75.0CCC 76.OCOO 77.0CCC 78.0CCC 79.0CCC eo.ococ ei.occc 82.0CCC 3.0000 R&S 152081 85.000C ci 7917844 7 0.0476443917 i. .OCCC 86.000C 0.0079985632 0 .0484G761G5 86.OCCC 7.0000 0.0081310456 0.0498319tG4 67.OC0C c es.ococ 69.000C 50.000C 0.C034179105 0*0085530340 O.COE5997ol5 0.0504848696 0.0508543ei2 0.0517573170 68.0C0C 69.OCCC SO.OCOC 91.0000 0.C090B88273 0.0522902669 91.0C0C 92.Q00C 0.0091661417 0 .C535E8bttO 52.OCCC 53.000C 0.C096l8e542 0.059351BCE6 53.OCCC 54.CC0C 0.0097569e>74 0 .0557135 596 54.OCCC 55.0C0C 0.0C98993all 0.0570824519 55.OC0C 96.QG0C 97.000C C.C103204176 0.C1056629C9 O.C5824623b3 0.0606013367 56.0C0C 97.OCCC 56.000C 0.C109909372 0.0631522334 . 96.0C0C 59.000C 0.C117450356 0.0666660615 59.0C0C J. * R&S152082 tuirorigenic F> ricy Z s zr l Pu t i on Calculates Assuming quipncent Ocses Can 6e EAtrspolateo Between Species on a 11) mg per Bocy weignt lh) Basis or 12) mg per Surface Area (SA) Basis rcentile 17.6000 18.0000 19.0000 20.000C 21.0000 22.0000 23.0000 24.OCOC 25.0000 26-0000 27.000C 2e.oooc 29.000C 30.00CC 31.0000 22.000C 33.C00C 34.0000 35.0000 36.0000 37.0000 38.0000 39.0000 40.0000 41.000C 42.0000 43.0000 44.000C 45.0000 46.0000 47.0000 48.0000 49.0000 50.0000 51.0C0C 52.0000 53.0000 54.0000 55.0000 56.0000 57.000C 58.0000 59.000C 60.0000 el.OCOC 62.0000 63.0000 64.0000 65.0000 66.0C0C 67.0000 66.0000 69.G00C 7n aAAr Potency (1/lmg/kg/cty I) Calculated Using Extrapo1 ation Assumption: BW SA Percent He 0. 0.C005611179 0.0010148041 0.0010154366 0.0011749854 0.0013267462 0.0013267462 0.0013685476 0.0014714494 0.0C14714494 0.CC14714494 0.0014714494 0.0016097173 0 .0016097173 C.001O097173 0.0016097173 0.0016097173 0.0017354523 0.0C17420996 0.CG1742O996 C.CC17420996 0.CC17420996 0.0017420996 0.C01742C99O. 0.C016690773 0.0018690773 0 .C016690773 0.CC16690773 C .0016690773 0.0019910738 0.0019910738 0.C019910736 C .0020652630 C.0021052632 0.0021004659 0.0021064659 0.0024735923 0.0024735923 0.0024735923 0.C02S360672 0.0028703306 0.OC287O33C6 0.0028703806 0.0026703806 0.0032219272 0.0032400019 0.0032801141 0.CU3280Il4l 0.0032601141 0.0034188544 0.0036572944 0.0036572944 0.0036572944 A AAA 4 , , ^ #i 0. 0 .0035775 830 0.00624 75200 0.0062514152 0.0072336569 0.0081679663 0.0081679663 0.0064252951 0 .0Q905E8C15 0.0090586015 0.0090566C15 0.009C566C15 0.0099100312 0.0099100312 0.0099100312 0.0C991C0312 0.0099100312 0 .0106841046 0.0107250279 0.0107250279 0.C107250279 0.0107250279 0.0107250279 0.0107250279 0 .0115067502 0.0115067502 0.0115067502 0.0115067502 0.0115067502 0.0122578C79 0.01225 78C79 0 .0122578079 3.0127145443 0.0129614165 0 .0129805179 0 .0129605175 0 .01522 3 74 9 0.0152283749 0.0152283749 0 .0174S99C85 0.0176711548 0.0176711548 0.0176711548 0.0176711548 0 .0198354088 0.0199466832 0 .0201936290 0 .0201536290 3.0201936290 0 .0210477673 0-0225156555 0-0225156555 0-0225156955 17-3CCC le.ococ 19-0C0C 20.0CCC 21.OCOC 22.0CCC 23.0CCC 24.0C0C 25.0C0C 26.0CQC 27.0CCC 28.0CCC 29.0COC 30.0CCC 31.0CCC 32.0CSC 33.0C0C 34.0CCC 35.0CCC 36.0CCC 37.0CCC se.occc 39.0CSC 4O.0CCC 41.0CCC 42.0CCC 43.0CCC 44.0CCC 45.0CCC 46.0CCC 47.0CCC 48-OCCC 49.0CGC 50.3CCC 51.0CCC 52-0C0C 53.0C0C 54.3C0C 55.0000 56-OCCC 57.0CCC se.ococ S9.0CGQ 60-0CCC 61.OCOC 62-OCOC 63.OCOC 64.OCOC 65.OCOC 66.OCOC 67.QC00 6b.ococ 69.0CCC R&S152083 71.0000 72.0000 73.0000 79.G00C 75.0000 76.QCQC 77.QOOC 76.000C 79.0000 E0.000C 61.0000 82.QQ0C 63.0000 69.0COC 65.COCO 66.0000 67.0C0C 66.0000 69.0000 90.0000 91.0000 92.0000 93.0000 99.0000 95.0000 96.000C 97.000C 96.0000 99.0000 0.00370 ,o39 0.003703-6639 0.0037036639 0.0037036639 0.0037999196 0.0037999196 0.C090362515 0.0090562302 0.0090562302 0.0090666526 0.0090668526 0.0C9068352O 0.0091919901 0.0091919901 0.0091919901 0.C09200931o 0.0C92009316 0.009200931b 0.0099769099 0.0095356899 0.0095356399 0.C09932999S 0.C099969199 G.CC99969199 0.0059797759 0.0059797759 0.C056957076 0.0059796696 0.0069061992 0.0226011589 0.0226011589 0-0228G11569 0 *0226011589 0.C230551992 0 .0230551992 0.02 98986977 0.0299716956 0.029971695b 0.02 51725 21b 0.025X725216 0.0251725316 0 .0259996661 0 .0259996661 0.0259996661 0.0256625 217 0.0258625317 0.0256625317 0.0275615266 0.0279239 312 0.0279239312 0.0302660035 0.0307752211 0.0307752211 0.0337355807 0.0337355607 0.0362962186 0.036e130676 0.0399369965 71.0CU 72.OCQ0 72.0CCC 79.3C0C 75.0C0C 76.3CCC 77.0C0C 76.OCCC 79.0C0C 60.OC0C ei.ococ 62.0CCC 63.0C0C 89.0CCC es.ococ 66.OCCC 67.0C00 te.ococ 69.0CQC 90.0C0C 91.OC0C 92.0C0C 93.0C0C 99.0C0C 95.OCCC 96.0C0C 97.0C0C 96.OCCC 99.0C0C `l Tumorigenic Potency Distribution Calculatec Assuming Equipctent Ocses Can Be Extrapolated Between Species on a tl) mg per Bocy height IfiM) Basis cr 12) mg per Surface Area (SA) Easis IbC.'.Ak. L/.a s Percent!le 26.7750 27.0C0C 26.000C 29.000C 3O.OC0C 31.0000 32.0000 33.0000 34.0000 35.COOC 36.0000 37.0000 38.0000 39.0000 40.0000 41.0000 42.000C 43.0000 44.Q000 45.000C 46.0CCG 47.0C0C 48..0C0C 49.0000 50.Q0CC 51.0000 52.0000 53.00SC 54.000C 55.0000 56.000C 57.0000 58.0C0C 59.0000 60.0000 61.000C 62.000C 63.0000 64.0000 65.000C 66.Q00C 67.0000 68.0000 69.GCQ0 70.00CC 71.300C 72.000C 73.000C 74.0000 75.CCOC 76.000C 77.000C 7R Potency t1/tmg/kg/day]) Calculated Using Extrapolation Assumption: Em SA Percentile c. 0.0000507622 0.C002C960ie 0.0004298591 0.0005620106 0.0009720490 0*0012379130 0.CC146139C2 0.0016829012 0.0021019625 0.CCZ3729971 0.0026725268 0.0029587736 0.0035185416 0.0036764252 0.0036315980 0.0042651291 0*0046149381 0.CC47179731 0.0047961711 0.0050184107 0.0C54e32995 0.0057254005 0.0056275208 0.0060069736 0.0063974769 0.0067353073 0.0068979263 0.0070492476 0.0070492476 0.0071712560 0.0073190155 0.C0765e2120 0.0080666031 0.0062255788 0.0082972646 O.CG638757b8 0.0084361104 O.C06h361104 0.0086623031 0.0088179633 0.C091513284 0.0C9471936*. 0.0094792508 0.C095t870o2 0.0095945485 O.CC9912el94 0.0099640759 C.009973*217 0.0099734217 O.C101132747 0.C102331033 ft 44v 0. 0.0006275531 0.0026408150 0.0054*94015 0.0071251357 0.0122466804 0.0155967139 0.0185654219 0.0212158430 0.0264530215 0 .0303103067 0.0338076092 0.033C34et0O 0.C452052CS7 0.04 77245301 0.048369C921 0.0553291105 0 .0594863114 0.0605577401 0.0626344010 0.063916049V 0.0698217377 0.0735943588 0.0 775177230 0 .0797523020 0.083774*325 0.0864733309 0.0504 72020 2 0.0956730517 0.0556720917 0.0965001956 0.0578169367 0.1016124487 0 .1065206666 0.1116283746 0.1121719629 0 .1126113012 0.1145228744 0.1145228744 0.1151535609 0.1190514735 0.1221539400 0.1278152466 0.1206533 326 0.1296197508 0.1302181631 0.1332766947 0.1349635545 0.1353602707 0.1353602 707 0.1363334507 0.136e39Ae2 A 1 "n* r - - 26.775C 27.0COC 28.OCOC 29.0CCC 30.0CCC 31.0CCC 32.0C00 23.0CCC 34.0CCC 25.0CCC 36.0CCC 37.0CCC 38.0CCC 39.0CCC 40.0CCC 41.0C00 42.0CCC 43.0CCC 44.3CCC 4S.0CCC 46.0CCC 47.0COC 46.0CCC 49.0C0C 5C.0CCC 51.OC0C 52.0C0C 53.0C0C 54.OC0C 55.0C0C 56.0CCC 57.0C0C 58.0C0C 59.0C0C 60 * 0 CC C tl.OCCC 6Z.0CCC 63.0000 64.OCOC 65.OCOC 66.0CCC 67.0CCC 68.QCCC 69.OCOC 70 .OCOC 71.OCOC 72.OCOC 73.QCCC 74.OCOC 75.OCOC 76.0 CCC 77.0CCC seo?stS5>1 37 JO.GCGC ei.ocoo 82.000C 63.0000 69.0000 65.0000 66.0000 67.0000 88.0000 89.000C 9C.0Q0C 91.OCOC 92.OCOC 93.0000 99.0000 55.000C 96.000C 97.0C0C 98.000C 99*000C c.c;.C7,',;z7g 0.0108 3989 0.0109590522 Q.0110216215 0.01119o5789 0.C111928107 0.0119462950 0.01x9962950 Q.Q11&1&7953 0.0116897561 0.QU7690376 0.011993008e 0.0121220953 0.0129753751 0.C129853618 0.C130839720 0.0139910503 0.0136979069 0.C190798213 0.C199791398 -..'. i . _ j Q .1 5** 702 02 0 0 .19 7206157** 0 .1936699 813 0.1<t93C60940 0.1512829799 0 .1512C29 799 0.1553995829 0.1553995629 0.1573326191 0.1586595908 0.1595713993 0.1620917022 0.1690292189 0.1689127088 0.1699593579 0.1775 769 790 0 .1630699078 0.185e78039 0.1910927995 0.1965127190 81.Ot - B2.0CQC 63.0CQQ 89.occc 85.0CCC 66 OCOC E7.0CCC 88.0CCC 89.0CCC 90.OCOC 91.OCOC 92.OCOC 93.0CCC 99 .OCOC 95.0CCC 96.OCOC 97.OCOC 96.0CCC 99.0CCC R&S 152086 Percent!le O.CCOC l.OOQC 2.COOO 3*0000 4.0000 5.000C 6.0000 7.3000 S.OOOC 9.0000 10.0000 ll.COOC 12.0000 13.0000 14.000C 15.0000 16.0000 17.0G0C 16.0000 19.0000 20.0C0C 21.0000 22.Q0CC 23.000C 24.0C0C 25.000C 26.000C 27.0000 28.0000 29.0000 30.0000 31.0000 32.0000 33.0000 34.0000 35.0000 36.0000 37.0000 38.0000 39.0000 40.000C 41.OC0C 42.C00C 43.0000 44.0000 45.0000 46.QC0C 47.0000 46.0C0C 49.0000 50.0000 51.0000 52.0000 53 *0000 - -L i ; ; Eogen/Smitn 2/10-13/Ec COMPOUNDS: VCt. VCCl, OCE, EM. CLFm Calculated C I str ibut i ens cf Individual Risk. STATICN A station e STATICN 0 0. 0.CQ0QH7384 0.0000149576 0.0000171173 0.C0001&6231 0.00002C2142 0.0003215941 0.0000223705 0.0000238056 0.0000247567 0.0000257650 0.0000265631 0.0000274636 C.O0CU28250O 0.0000290385 0.0000297792 0.C0003C4257 0.0000310246 0.0003318354 0.0003325451 0.0000332134 0.0000338986 0.0C0334o417 0.0000354209 0.0000363165 0.0000371377 C.0000361047 0.0000390199 0.0000400237 0.0000412684 0.0003423530 0.0003437418 0.0000451495 0.00004 70129 0.0003466159 0.0000510023 0.0003544 181 0.0000617547 0.0000730774 0.0003630700 0.000090l4o9 0.GO0095311C C.C000991074 0.0001029710 0 .0C010&0591 0 .0001090590 0-0001120o32 0.0001152433 0.0001181696 0.0001212229 0.0001242388 0.0001279027 0.0001312318 0.0001352057 o. 0.0000074220 0.0000093685 0.0000105254 0.0000114656 0.0000123675 0.0000130636 0.000013745e 0.000C14 3756 0.C00C149180 0.0000155280 0.000015 9662 0.0000165286 0.0000169985 0.0000175196 0.CC00160C47 0.0000183546 0.C00C16 8916 0.0000193605 0.C00G193277 0.0000203269 0.000C203272 0.0000213097 O.OOOC218615 O.OOOC224 705 C.OCO0228946 0.C00C23529C 0.0000242234 0.000C250636 0.CC0C253C34 0.0000264556 0.C00C274216 0.000C264245 0.0000294635 0.0000305580 0.000032 4 2o2 0.0000349260 0.0000406651 O.COOC476779 0.000054C435 O.OOOC56 8C7C O.COOC622C14 0.000 06*5 162 0.C00C670257 0.O00C69C5o5 O.COOC7C969C 0.C00C72 7919 0.0000746921 0.0000765475 0.0000765C02 0.0C0C80213C O.OOOC8Z3 139 0.0000645594 o.nnnrfi.'** i * C. 0.0000066312 C.0000064504 0.0000094e57 0.0000101036 0.0000108344 0.0000115001 C.0000121C13 0.0000126325 0.000013148C 0.0C0C136965 0.0000142634 G.O000148384 0.0000153391 0.0000158206 C.0000162584 C .0000166756 C .0000171831 0.0000176232 C.C0001S0155 0.0000184686 0.0000189382 0.0000194252 0.0000199231 C .0000205214 C .0000210566 C.Q0G0217582 0.0000223537 C.00002302 69 C .0000236635 0.0000244092 C .0000252452 C .0000261623 C.000 C27167C 0.0000233033 0.0000297674 0.0000316742 0.0C0Q35968C 0.000042395c 0.00004 6C22 7 0.0000517504 C.0000541636 0 .0000562566 C.000C58564C C.0000604466 C.OOOC62CG76 0.0000637651 0.0000657357 0.0000679010 0.0000697566 0 .000072169 7 0.0000744212 C *0000767982 3J w CJI -CoJD S T A T 1 ON -0.000060c -0.0000575 -0.0000544 -0.0000515 -0.0000491 -0.0000466 -0.000045C -0.0000432 -0.0000415 -0.0000396 -0.0000381 -0.0000356 -0.000C34C -0.0000324 -0.0000306 -0.0000282 -0.0000255 -0.000023T -0.000C216 -0.000019C -0.0000166 -0.000014* -0.0000125 -0.0000116 -0.000009* -0.0000075 -G.000CC6* -0.000005t -0.000005; "0.000004* -0.000004' "0.000004* -0.000004. -C.0Q0C04< -O.O0CCO3' "0 .000003' -0.OOCCO3-0.000003 -0.000003. -0 .000003( -0.000002 -0.000002 -0.000C02 -0.000002 -0.000002 -0.000002 -0.000002 -0.000001 -C.000001 -0.00C001 -0.000001 -0.000001 -O.OOCCOl r\rs r r\n \ - i/C C 55 .0000 56.0C0G 57.000C 5B.00C0 59.0G0C 6C.000C cl.OOOC 62.000C b3* 0 00 C 64 >0000 tS.OOOC 66*0000 67*0000 te.oooo 69.0000 70.0000 71.000C 72.0000 73.0000 74.0000 75.0000 7b.0000 77.0000 78.0000 79.Q00C 60.0000 61.0000 62.0000 63.0000 64.0000 65.C00C B6.CC0C 67.C00C ee.oooo 69.0000 90.0000 91.0C0C 92.0C0C 93.C00C 94.0000 95.0000 56.0000 97.000C 58.000C 99.0000 O.v J1431934 0.CO014753O4 0.0001520036 0.000155b557 0.0001599696 0.0001636242 0.0001674493 0.00017X2926 0.0001759144 0.0001004312 0.0001854171 0.0001897237 0.0001943767 0.0001991257 0.0002042394 0.0002096224 0 .0002152158 0.0002201937 0.0002254053 C.0002316636 0.0002371576 0.0002431331 0.0002497201 0.0G02564164 0.0002632263 0.0002726368 0.0002026490 0.0002964873 0.C003144502 C.G003390945 0.00037e4977 0.00C4 330993 0.C006022413 0.CC0S746531 0.CC1Q024015 0.0010721035 0.001x265214 0.0011773153 0.0012234695 0.C0126C7755 0.0013030332 0.0013433116 0.C014258O66 0.0015340221 0.0013085926 c .coo ee 0572:- 0.000C9G9279 O.OOOC935C64 O.COOC959528 O.COOC9e40fc2 0.C001C03645 0.0001036 3oC O.OGOlCo3234 0.CCQ1069515 O.CGO1116351 0.COO 1139339 O.OCC 1168312 0.0001198681 0.0001236307 0.0001266354 0.00013C2695 0.0001335675 0.000137779* 0.0001406766 0.0001440686 0.0001456596 0.000152414t 0.0001556880 0.0001599423 0.0001643577 0.0001691096 0.000174912E O.CCO1610220 0.000191131C 0.C002033676 0.0002190869 0.C002450236 0.C002L2996C 0.0003958667 0. COO 5829626 0.0006668878 0.000714C977 0.0007506026 0.0007856230 0.0006155349 0.0006414 365 0.0006704795 0.COO952050 0.0009515447 0.001C58915C C.0012C6825C C'COCoCC't i; .0000065959 0.0000896391 0.000093100 7 0 .0 0 0 09 6 72 5 5 0.000 1006619 0.0001055916 C.C001053911 C.0001139935 C.0001104010 0.0C0122828C 0 .0001273001 0.00013C543e C.0001347541 C *OOO1305cO9 C.OCO1423528 C.CCO 1464086 C.0001513642 C .0001556020 0.0001594999 C .0001646039 0.0001689261 C.0001732660 0.0001781289 0.0001834165 C.C00189C66C C.0001963395 0.0002033284 0.0002111578 C.C0C2199315 C.0002306007 0 .0002500737 0 .00 02807505 0.0003704334 C.0005154652 0.0005838092 C .0006263086 C.OCOeS76735 0.0006061612 C.0C0711C817 0.0007356133 C.C007671033 0.0007932837 C.0008353190 C .0005172775 C.001C3c255t vuQJCQ 10 -C.0000008 *0.0000007 -0.0000005 *0.0300003 -0.0000002 -0.0000000 c.oooccoo C.000C002 0.0000004 O.OOOGOG6 0.0000009 0*0000012 C.0000017 0.00000 25 C.OOOC036 C.OOUOG47 0.000C057 O.OOOCOoJ 0.0000076 C.00CC062 0.000C06S 0.0000095 0.0000101 0.00001C7 O.OOOCll* G.000012C 0.0000121 G.00U0l3t 0.000015: O.GOQOle? C.000C18* 0.0000221 C.000040t C. 000075: 0.00009 4( 0.0001061 C. 000116 G.0001251 C. 000132* O.U00140 0.000150 0.000160 0.C00172 0.000X91 0.000225 JO w Oi ooroo GO  'y - - Bcgen/in th Fet>. 1966 c COMPOUNDS: VCL. VOCL DCE, BNZ * CLFM STATIONS A,fi,0 odd f- Weighted Average Individual Risk Weiyhts: Percent ile A .25 3 .25 0 .25 F .25 0. l.ococ 2.C00C 3.000C 4.000C 5*0000 6.000C 7.000C e.oooc 9.000C 10.0000 ll.OOOC 12.000C 13.0000 14.0000 c 15.0000 16.0000 17.0000 16.0000 19". 0000 20.0000 21.0000 22.0000 23 *0000 24.000C 25.0000 26.000 C 27.0000 26.0000 29.0000 3C.000C 31.0000 32.0000 33.000C 34.0000 35.0000 36.0000 37 *0000 38.0000 39.0000 40.CC0C 41.0000 42.0000 43.0000 44.0000 45.0C0C 46.000C 47.0000 46 .OQOO 0. 0.0000119460 0.000015o075 0.0000179668 0.0000207219 0.0000223633 0.0000254846 0.0000276966 0.0000300740 0.0000322668 0.0000337775 0.0000359101 0.0000375922 0.0000396047 0.0000412700 0 .0000427910 0.0000443832 0.C000459137 0.0000475331 0.0000491222 0.0000505526 0.0000521641 0.0000534101 0.CC00551213 C.0000567550 0.0000563104 0.0000595291 0.0000609396 0.0000624 920 0.0000e39064 C.0000652964 0.0000666952 0.0000661751 0.0000695121 0.0000706344 0.0000721014 0.0000733940 0.000074t)9iQ 0.0000763045 0.0000777944 0.0000792022 0.0000809779 0.0000625569 O.CCOOe43548 0.C0008602BC 0.0000875945 0.0000892168 Q-C000912 793 0.0000923251 A .25 t .40 C .15 F .20 C. 0.0000122483 G.0C0C1C4225 o.cccoieefc2i 0.0000208173 0.0000223267 0.0000257504 0.0C00262544 C.CCC0308466 0.0000226372 0.0000356674 0.0000379173 0.0000397931 0.0C00413243 C.0C00429528 0.0CC0444416 0 .000045924 3 0.0C0C4 77669 0.0000492397 0.0C005C7661 0.0000523307 C. 0000528351 0.0000553665 0.0C00570069 C .0000 564052 0.0000600574 0.0000615665 0.0000622521 0.0000647120 0.0CCC6e3750 0.0000677963 0 .0000690913 0.0000706720 C .0000 717576 G.0C0G7233C6 0.0000 748465 0.0000763210 0.0000778514 0.0000793699 0.0000609702 0.0C00826C75 0.0000841434 0.0CC0e5611b 0.0000874245 0.0000e52e29 0.00009C9C96 C.CC00927660 C .0000 545262 C.0000963741 Fercentile O.OCOO 1.CC00 2*0000 3.0C00 4.0000 5.0C0C fc.CCOC 7.0C00 8.0000 9.0C00 10.0C00 ll.OOOC 12.0C0C 13.0000 14.0000 15.C00C 16.0000 17.0000 18.0000 19.0000 20.0000 21.0000 22.0C00 23.0000 2 4 .0000 25.0000 26.0000 27.0000 23.CC0C 29.0000 30.0000 31.0000 32 .0000 33.0000 34.0000 35.CC00 36.0000 37.0000 36.0COC 39.0000 40.UC00 41.0000 42.0000 43.0000 44 .CCOO 45.0000 46.0000 47.0C00 48.000C R&S152089 <*9.0000 50.000C 51-CCOO 52.QOOG 53.0000 59.0000 55.0000 5&.000C 57.0000 se.oooo 59.0000 60.0000 61.0000 02.0000 03.000C 69.oooc 65.000 C 6.0000 67.0C0C te.oooc 69.000C 70.0000 71.000C 72.000C 73.0000 79.0C0C 75.00CC 76.0000 77.0000 78.0000 79.0000 BO.0000 81.0000 62.0000 63.0000 69.0000 85.00CC 66.0000 e7.oooc 88.0000 89.0000 90.0000 .91.0000 92.0000 93.0000 99.0000 95.0000 96.0000 97.0000 98.0000 99.0000 0 CCC h lt:S c.ocoo^ss^e C.00Q099d262 0.000l01b**91 0.0001039926 0.00010b4* 39 9 0 .00010962*15 0.0001122982 0.0001157567 C.OOOilftfcObO 0 .0001227197 0.00012b79b7 0.0001316333 0.0001369030 0.0001939928 0.0001501922 0.0001591538 0.0001710379 C.0001&16358 0.000ie9b090 0.0001969361 C.0C02069036 0.0002137381 0.0002190300 0.0002266698 Q.CC02326950 0.0002399 111 0.0002950625 0.0002520022 0.0002596123 0.0002673615 0.0002793790 0.0002819232 0.0002903360 0.0002976529 0.0003068053 0.0003199969 0.0003299839 0.0003396795 0.0003939268 0.000353o567 0.0003653216 0.0003775376 0.0003887916 0.0009076859 0 .0009266392 0.0009508652 0.0009 789169 0.0005128299 0.0005533987 0.0006155258 0 * OCC 0 9 80939 C.0CC0599269 G.00CIC2190B 0 ,OCC 1 C 9b 79 9 0 .0001 C7l<*60 0.0CC1C57920 0.0001126752 0.0CC1150656 C.OL011769C8 0.OC012C7582 0.0001239 717 Q.OCO1271279 C.00C13C9e52 0.0001399603 0.0CC1390285 O.OCC1936627 0.0001965196 0.0C01593219 0 .0001552779 0.0001691932 0.GC017C9950 0.0CC177fat02 0.0CC1852956 0.0CC199e56 0.0002C53501 C.0002179657 0.0002206161 C.0CC2999C23 C .0002697587 0.0002659998 0.0CC2 999518 C.0CC3112532 0.0003220999 C.0CC3327C35 0 .0003 9 C9899 C.0003983519 0.0003579931 0.0003657997 C.0003751239 O.OCG3891729 0.CCC3 999676 0.0C09CfcO51b 0 .0009157669 0.0009 395696 0.0009516636 0.0009 729605 C. 0009960999 0.0005232969 0.0C05551788 0 .0006160105 0.0COc9275ee c <*9.0000 50.0000 51.CCOO 52.0000 53.0000 69 .0000 55.0000 6b.0000 67.0000 68.0000 59.0000 60.0000 tl.OCOO 62.0000 63.0000 69.0000 65.0000 66.0000 67.0000 68.0000 69.0000 70.0000 71.0C00 72.0000 73.0000 79.0000 75.0C00 76.0000 77.CCOO 76.0000 79.0000 eo.oooc bl.OOOC 8 2.0000 63.0000 69.0000 65.0000 6b.CCOO 67.0000 68.0000 69.0000 90.0000 91.0000 92.0000 93.0000 99.0000 95.0000 96.0000 97.0000 98.0000 99.0000 602s;ssy Percent!le 0. 1.0000 2.0000 3.000C 0.0000 s.ococ 6.000C 7.000C e.oooc 9.0C0G 10.0000 11.0000 12.0000 13.000C 14.0000 15.0000 16.0000 17.000C le.oooo 19.0000 20.000C 21.000C 22.000C 23.0000 24.0000 25.0000 26.0000 27.0000 26.0000 29.000C 3C.0000 31.0000 32.0000 33.0000 34.0000 35.0000 36.C00C 37.0000 36.0000 39.0C0C 40.0000 41.0000 42.0000 43.0000 44.0000 45.0000 46.000C 47.0000 46 .OCOC 49.CC0C 50.0000 51.0000 52.0000 53.0000 Bogen/Smith 2/10-13/Ee COMPOUNDS; VCL PCE. TCE. VDCL, CCE. BnZ * CLFn Calculated Distributions cf Individual RisK STATION A STATICS e station c 0. 0.0000167416 0.0003201954 0.0000225259 C.0000242155 0.0003256961 0.0003271932 C.0000263096 0.0000295966 0.0000307031 0.0000316542 0.0000326966 0 .0000336039 0.0000346373 0.0000355356 0.0000363311 0.0000370161 0.0000378112 0.0000365936 0.0000393749 0.0000401131 0.0C004C9161 0.0003418316 0.0000428108 0.0000438067 0.0003445365 0.0000454770 0.0003464649 0.0000475388 0.0000486140 0.0000497405 0.0000513301 0.0003527962 0.0003545322 C.00035o5647 0.0000596773 0.0000643914 0.0000760322 0.0003915892 0.0000990680 0.0001044989 0.0001090098 C.C001135631 0.0001166602 0.0001206o58 0.0001241229 0.0001284115 0.0001323431 0.000l36e215 0.0001420116 0.0001464406 C.0001554 665 0.0001631516 0.00017142c! 0. C.00CC104513 C.00C01255E1 O.OOC0135631 0.00CQ146549 O.CCC015C690 0.0000164566 O.OC00171433 0.0000176361 C.0CC0184297 C.COC019C747 0.C0CC197551 O.00C0202387 O.00CC207854 O.OOC0213115 O.CCC02160C4 0.00C02 22369 0.C0C02217C3 O.OCC0232621 O.OOC0236722 0.0000241711 0.0CC02 4c785 C.00C02 52247 0.00C0256257 0.00CC265473 0.00CC2 7C865 0.0000277467 0.0000284356 0.00002 91322 C.00CQ2 96595 C.OOCC3057E4 C.0000315562 0.00C03263C0 0.00C0338427 C.COCO 351800 0.00CC36E2C2 0.0000397141 0.0000*64039 0.00C05796E6 0.00C06452E1 0.00 CO 6 8 44 69 0.00C0715235 C.OOCC7417C5 0.00C0767352 C.00C0792412 0.00CCElt2ei C.0000644175 C.0000875623 0.C0C09C 2963 0.0UC093 70C7 C.00C0980230 0*0001027172 C.0001068566 o.cnr.i i t /405 c. C.00C01Q5567 C.000012406O C.0000137900 0.0000147735 0.0000156949 C.0000165174 C.0000172649 C.00001EC422 C.00CO1E7423 C.0000193151 C.0000199449 0*0000205678 C.C000210972 C.0000217091 C.OOC02232EO 0.0000227976 C.0000233639 C.000023E953 0.0000244075 C.C0C0249112 0.0000253937 C.OOC02567C3 C.C0C0265OEO C.0000272412 C.00C027E9c2 C.0000285023 C.00C0291974 C.0000296926 C.0000305469 C.00C0313912 C.0000323316 0.0000333016 C.0000345954 C.0000357623 0.0000375966 C.00004C244O 0.0000447861 C.0000522974 C.0000576410 C.0000tl3447 C.000064325b C.C00067C2E1 C.00CQ691ieB C.OOCO 715299 C. 0000741565 C.00C0769191 C.0000602985 C.0000835524 C.0000876839 C.C000929224 0.00009674 70 C.0001056147 C.nnni ; 5-371 p 33 w o CO STATION f -0.0000441001 -0.000038111. -0.000032H2' -0 .000026818* -0 .000021679* -0.000017246( -0.000013116-0.000008616 -0.000004945 -C. 00000374 8 -0.000003176 -0.000002666 -0.000002277 -0.000001956 -0.000001626 -0.000001341 -0.000001059 -O.OOOOCO724 -0.000000432 -0.000000161 0.000000102 C .00000037 2 0.000000653 0.000000916 0.000001165 0.000001406 0.000001636 0.000001673 0.0000021C6 O.OOOOC236S 0.000002595 0.00000282 ~ o.ooooo3ic: 0.00000331* 0.00000361* 0.000p0364< C.00000405' 0.00000439( 0.00000463' 0.00000494C 0.00000520' 0 .00000553' C .00000582 O.OOOOOolS 0.00000652 0.00000688 C.00000734 O.OOOOC778 C. 00000846 C.OOOOC907 0.00000964 0.00001068 0.00001147 n. onnn ^ 54 .CLOt: 55.QOOC 56.0000 57.0000 c 56.0000 59.3C0C 60.0C0C 61.0000 62.0000 63.00GC 64.0000 65.0000 66.000C 67.0000 te.oooo 69.0000 70.0000 71.0000 72.000C 73.0000 74.0000 75.0000 76.000C 77.0000 7C.0C00 79.000C eo.oooo 81.0000 82.0000 83.0000 84.0C0C '( 85.0000 86.0000 87.0000 88.0000 69.0000 90.0000 91.0000 92.0000 53.0000 94 .000 0 95.000C .96.0000 97.000C 98.000C 99.000C O.QCCi 3 300 C #CGOitcl400 0.0001967505 0.0002053009 0.0002127309 0.0CC22U341 0.0002291074 0.0002374263 0.0002460355 C.0002532971 C.C002&C4108 0.0002665594 0.0002754990 O.C0C2E23051 0.0002890742 0.0002954087 0.0003035968 0.0003120290 0.0003188752 0.0003255634 0.0003337023 0.0003422117 0.0003491150 0.0003587085 0.C003672591 0.0003757695 0.0003869332 0.0003988601 0.0004160306 0.0004327652 0.0009527254 0.0004891809 0.0005543724 0.0007449347 0.0009677429 C.0010927630 0.0011622346 C.0012161805 0.0012656278 0.0013107569 0.0013481090 C.0013977059 0.0014431083 0.0015204839 0.0016660416 0.0013914242 0.cgtll5l *93 C.GOCli92?71 C.000124C129 0.C0012916C5 0.0001334420 0.0OC1382014 C.00C143C019 C.0001474257 0.0001521993 0.0001565996 C.OOCUC5321 O.OOClt4?e55 C.00C1685263 O.COC172fc795 C.0001766196 O.OOC161C7G7 0.C0C1&5C113 C*OOClf94472 0.00C193C911 C.00019752C5 0.00C2025943 0.0002C7tl96 0.00C2118553 0.0002166571 C.OOC22203C5 0.00C2276990 0.0002345239 C.0002425023 0.0002519356 0.C0C2636519 0.0002762673 C.00C3CC416O 0.00C33S3321 0.0004476697 0.00C63C2672 0.0007125543 0.0007621924 C.00C8C1C&E6 0.000634 3418 0.0008637734 0.00CB919118 0.00C9262862 0.00C9553564 0.0010077254 0.0011076273 0.0012574432 C.l ;j.25*.OG1 C.0001351193 C.00C143c8tb C.OOOI5C7203 C.00015724C1 C.00016373Cl C.G0017C5682 C.0001769954 0.0001630609 C.00C18534t2 C.0001961023 C.00C202256& C.000202o51 C.00C2145035 0.0002196703 C.00C22*2651 C.00C23C911O C.0002371761 0.0002419357 C.0002471573 C.0002536896 C.0002599254 C.0002654939 C.0002716460 C.0002784427 0.0002654810 C.C00294l2c7 C.0003031442 C.00031417&6 C.00Q32447c9 C.00033774C7 C.000356C954 C.0003645051 C.00045894t9 0.0005636126 C.C00654C236 C.00070110C3 C.0007320404 C.0007656641 C.0007956789 0.0006216055 C.000855C121 C.OOC8E47o72 C.0009340050 C.00100C1422 C.0011262981 6.0000131966 0.0000140539 0.0000146532 0.0000155704 0.0000163612 C.0000170979 0.0000179092 C. 0000186928 0.0000196838 0.0000207714 0.0000220924 0.0000236661 0.0000256823 C.00002625 31 0.00003132 47 0.0000354304 0.0000386657 0.0000421539 0.0000454371 0.0000467792 0.0000523576 0.0000654247 0*0000586852 0.0000620299 0.0000655260 0.0000689765 0.0000731710 0.0000773962 0.0000623501 0.00006614ei 0.0000905731 0.0000960447 0.0001C31195 0.0001117394 0.0001230126 0.0001365960 0.0001511233 0.000lo58916 C.OOOI 79 77 81 0.0001926594 0.0002043543 0.0002171679 0.0002277545 C.0002429122 0.000258o257 0 .0002 88^14 67 39C3O grtoj o<o to Scccn/Smitn Feo. I9fc compounds: vcl. PCE . TCE. VOCL. CCE. B t*2 . CLFM 35 0W IoUV1> uCO STATIONS A, 6.3, dnd F : weighted Average Individua1 R i sw keiynts: Percentile A .25 B .25 0 .25 F .25 A .25 E .40 C .15 r .20 (test) A .1 e .1 0 .1 F .7 l test > A .05 e .05 0 .05 F .05 0. 1.0000 2.000C 3.0000 4.000C 5.0000 6.000C 7.000C 8.000C 9.0000 10.0000 11.0000 12.0000 13.0000 14.000C 15.0000 le.oooc 17.0000 le.oooc 19.0000 2C.000C 21.0C0C 22.000C 23.0000 24.Q00C 25.0000 Zfc.GQOC 27.0000 28.0000 29.0000 30.0000 31.0000 32.0000 33.0000 34.0000 35.0000 36.0000 37.0C00 36.0000 39.0000 40.0000 41.0000 42.0000 43.0000 44 .OCOC 45.0000 46.0000 47.0000 46.OCOC 0. 0.0000204584 0.0000242386 0.0000279106 0.0000311852 0.0000349727 0.0000378378 0.0000403607 0.0000437934 0.0000467385 0.0000497234 0.0000524977 0.0000551247 0.0000582948 0.000060S146 0.0000633737 0.0000656121 0.0000674726 0.0000695475 0.0000719375 G.0000744128 0.C000 770200 0.0000794324 0.0000816143 0.0000837869 0.0000857 691 0.0000876149 0.0000694127 0.C0009l419e 0.0000935049 C.0000953721 0.0000977037 0.0000997645 0.0001019075 0.000 L037152 O.CCO1058274 0.0001C7&Q90 0.0001097040 0.0001117766 0.0001136784 0.0001158186 G.CQ01180233 0.0001203513 0.0001229854 0.0001252108 0.0001275451 0.0001297198 0.0001325339 0.0001353096 0. 0.00C0211545 C.0CC0246190 C.00C0275176 0.0000304999 0.00C0341969 0.00C03ei523 0.0000413655 0.00CQ442506 0.0000468923 C.00C0499340 C.0000524410 C.00CC5519E3 0.C0C0582553 C.00CCo0tl22 0.0000628670 0.0000653010 0.0000678034 C.0000700922 0.0000719697 0.0000741625 0.0000766476 0.C0C0792382 C.0000615102 0.0000634925 0.C0C0655734 0.00C06 75942 0.0000697765 0.0000916467 0G0CG94 2213 O.COC0962963 0*00009 83643 C.0001003667 0.00C1G2 6966 C.00C104 3956 0.0001065292 0.0001084594 0.0001106679 O.OOC112c51b 0.00C114 5B**5 C .0001168656 C.00C119C925 O.COC1209054 C.OOC1229395 0.00C12 52725 0.0001272oc5 0.0001298882 0.0001324383 O.OOC135 1530 C. C.0OCQO48512 C.00C0087676 C.00C011C357 C.000013200E 0.0000155844 C.0000176491 C.0000194145 C.0000211199 C.00CQ225700 0.0000235269 C.0000255765 0.0000267758 C.C0C0279610 C.0000293068 0.0000304310 0.00003185 e.0 0.0000330773 C.0000343715 0.0000355260 0.0000368745 0.0000379083 C.0000390427 C.0000401178 C.000041441C 0.0000426145 0.0000436526 C.000044656** C.0000458641 C.00004 7Z9C7 C.0000467736 0.0000498835 0.000051C056 C.0000522020 C.0000536194 C.COCO 548920 C.0000560758 C.0000575C96 C.0000590906 C.C000606580 C.0000620599 C.0000638321 0.0000654171 C.0000671986 C.00006b9713 C.00C07C7d90 C.0000727128 C.0000751181 C.OOOO 772350 -0.00001644 0( -0.0000090311 -0.00000162 7' 0.000002 74 3` 0.000004900 0*000006846. 0.00000808 1 0.000009196 0.00001024 8 0.000011369 0.000012379 C.OOOO13360 0.000014179 0.000015041 0.000015933 0.000016753 0 .000017o96 0.0000U362 0.000019167 0.000019892 0.000020576 0.000021495 0.0000 22082 0.00002264* 0.00002355C 0.00002423 0.00002514: 0.00002593: 0 .00002657' 0.00002741' 0.000028131 C.003023860.000029710.00003064 C.00003158 0.00003240* 0.00003342 C.00003456 0.00003549 0.00003664 0.COOO3773 0.00003915 0.00004035 0.00004155 0.00004282 0.00004** 37 0.00004557 0.00004736 0.00004891 99.OOOC 5C.OCOO 51.0000 52.0000 53.OOOC 5*.OOOC 55.0000 56.0000 57.0000 56.0000 59.0000 60.0000 61.OOOC 62.0000 63.0C0C 69.0000 65.OOOC 66.000C 67.0000 68 .OOOC 69.0000 70.0000 71.0000 72.OOOC 73.OOOC 79.0000 75.0000 76.0000 77.OOOC 78.0000 79.OOOC 60.0000 El.0000 62. OOOC 63.OOOC es.oooo 85.OOOC 66.C00C 7.0000 66.0000 69.OOOC 90.CC0C 91.OOOC 92.0000 93.0000 99.0000 95.0000 96.0000 97.0000 98.0000 99.OOOC 0.-. J13 7 6 5 5 2 0 .COO 1 <*07559 0 .0001 <*35693 0.0001 <*6< 529 0.0001993753 0.0001523796 0.0001555732 0.0001596615 0.0001693265 0.0G01cfiQ505 0.0001730996 0 .000a776 7x6 O.DOOie3&QOO 0.0001692681 0.0001997999 0.0002017037 0.0002095510 C.0002160812 0.C002297096 0.0002307991 0.0002369559 0.0002957089 0.0002528513 0.0002599996 0.0002673251 0.0002793979 0.0002805328 O.COOZ883Q72 0.0002966691 0.0003052506 0.0003129182 0.0003209997 0.0003272209 0.0003350963 0.0003932383 0.0003520933 0.0003619785 G.0003710391 o.coo3&ne96 0.0003913370 C.0009007559 0.0009137709 0.0009266316 0.0009926630 0 .000958*1003 0.0009791230 0.0005015509 0.0005291859 0.0005669999 0.0006076190 0.0006669510 C.C0C13 77227 C.00C19 0C779 C.C0C1<*2 7951 C.G0C1<* 52163 C.OOC1<*'2E3 C.C0C15C6127 C.0QC159Co27 0.00C1575702 0.0001612672 C 00Clt9<*b25 C.0001689655 0.0001723213 C.00C1769o6 0.0001606079 0.0001653979 0.C0C1695BC7 C.00C1591297 ' C.0001996267 0.0002056536 C.OOC21C9U1 0.00C2172966 O.OOC22 9 6297 0.0002332696 C.00C29 2C739 C.COCZ552U2 C.00C266 7731 0 00 02 5 C 79 76 0.0002967759 0.00C3116931 0.0003275159 0.0003379013 0.0C03995175 0.0003627079 0.0003710679 O.COC36C7669 C.00C3905865 0.0009001763 C.0009056862 0.00 0916 3790 0.000929S799 0.00C9921397 0.0009599519 0.0009669131 0.0009632953 0.00099965C1 C.00C5183919 0.0005925868 C.C0C5795268 0.0006129660 0.00066 6 7765 0.0007551039 .0000793015 C.0000813925 C.OOCO = 35<*t 7 C.0000859501 c.oocoaetoti C.00009C7375 0.000092635b C.O0CO951255 C.0000975951 C.00010C2750 C.000102c7tl C.0001C53669 C.0001076213 C.0001102709 C.0001130905 0.0001156360 C.0001166579 C.0001215133 0.0001293996 0*0001279853 0.0001306368 0.0001339368 0.0001363976 C.0001399772 C.0001926068 0.0001969926 C.0001959200 C.0001533030 0.0001569610 0.0001593569 C.0001626595 C.0001660865 0.0001695919 C.0001732191 C.00017ei006 C.0001630363 C.000ie69070 C.00019239GG C.000196C053 C.0OC2011726 C.0002060791 C.0002132296 0.0002219399 0.0002286393 C.00C2366906 C.00029 55*9 76 C.0002553966 C.0002656395 C.000280138 C.0003019675 C.00033e5351 C. 00005096 0.0C305207 C.00005365 0.00005505 0.00005659 0.00005837 0.000055 78 0.00006126 0.00006260 C. 00006997 0.00006627 0.00006757 C.00006959 0.0000711& 0.00007299 0.00007957 C.0C007bb3 0.0000 7635 0.00006006 C.00000165 0.00006366 0.00008566 0.0000677e 0.000095t 0.00009252 C.00009971 0.00009736 0.00010005 0.00010316 0.00010563 0.00010699 0.00011295 0.00011652 0.00012060 0.00012975 0.00013015 0.00013556 0.000x9155 0.00019 7 6c C.00015935 0.0001609} C.000169 25 0.00017622 0.0001665: 0.0001962c C.0002C7GC C.00021611 0.00023136 0.00029610 C.00026937 C. 0002970: B23o CO coruoot c Table 2.3 Calculation of Increased Annual Carcinogenic Risk to Individuals for Comparative Purposes Compound EPA 95Z UCL Potency* (mg/kg/day)-* Individual Dose* (mg/kg/day) Annual Risk* (x 10) Vinyl Chloride Perchloroethylene Trichloroethylene Vinylidene Chloride 1,2-Dichloroethane Benzene Chloroform .0175 .051 . .011 1.16 .091 .029 .007 2.5 x 10~ 2.0 x 10-4 2.3 x 10-4 1.1 x 10**4 1.9 x 10" 9.4 x 10-9 1.4 x l0-fl .062 .15 .036 1.9 .25 .039 .014 Total = 2.4 * EPA potency values are for lifetime exposure and are taken from the EPA's. Health Assessment Document for Trichloroethylene (EPA 600/0-92/006?. July 1965) p. 9-133. * Doses derived from "Mean" values presented in Table 2.1, multiplied by the factor (l5/24)x(0.5)x(0.5) = 0.15625 to account for partial daily exposure, dilu tion and partial absorption, as explained in the text. c Annual risk calculated using 70 years as human lifespan. R&S152095 (0 Table 2.4 Table of Comparative Cancer Risks Daily Exposure Situation Person at Dose Individual Annual Risk3 (mg/kg/day) Risk (x 10*) BKK Resident Adult Youth See Table 2.3 See Table 2.3 2.4 3.4 Drinking 2 liters of aver age U.S. tap water con taining 86 ppb chloro form Adult 2.45X10'3 2.5 Swimming for 1 hr in a pool Child ' 0.01 10 Eating a peanut butter sandwich containing 2 teaspoons of p. buttter 2 ppb aflatoxin Bt Adult Child 0.9 U x 10-* 2.133 x 10-* 3B 88 Worker exposed to 50 ppm perehioroethylene for 8 hr. e.g., in a dry cleaning shop, for 5 days/week Adult 32.3 ~ 810.000 Worker exposed to 5 ppm vinylidene chioride for 8 hr. e.g., in an adhesive manufacturing plant, for 5 days/week Adult 1.90 - 890,000 Exposure Assumptions: Adult weighs 70 kg end inhales 20 m3 ot air per day: Youth are aged 0-13 breathmg a time-weighted average ot 0.4143 m3/kg/day (equivalent to 29 m3 per 70 kg per day); and Child weighs 30 kg. R&S 152096 APPENDIX E 23 C/3 cortnoo CD R&S152099 ANALiSIC OF VARIANCE OF THE DATA IN EPA AND DHS' 1984 EXTENDED MONITORING PROGRAM Analysis of variance (ANOVA) is a statistical. technique that isolates and assesses the contribution of one or more factors to an outcome of interest. Independent categorical variables (factors) are investigated for their influence on the dependent continuous random variable (outcome). Assumptions underlying ANOVA are: independence of the values, normality of the errors of the values, and equal variance for all observations. Two types of models used with ANOVA are the fixed effects model and the mixed effects model. In the fixed effects model there is one level of effect for each group f observations, and the assumption is that the difference is due to the fixed effect. In the random effects model, the effects are drawn from a prior distribution in which it is not possible to estimate the magnitude of the effects for one group of observations, but it is possible to estimate the overall variance. The mixed effects model contains both fixed and random effects. For the data in EPA and DHS' 1984 Extended Monitoring Program (CH2MHill, 1988), the independent categorical variables were: "type" (Priority I homes/control home), "agent1* (chemicals detected in the Priority I homes), and "sample date/calendar period"; the dependent random variable was "concentrations detected". Three-way ANOVA was performed on the data in the program for the primary factor of interest, "type" (that is, whether or not there was a difference between the concentrations detected in the Priority I homes and the concentrations detected in the control home). The two other factors investigated to ensure that the difference was not due to their influence were "agent" (vinyl chloride, 1,1-dichloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, perchloroethylene, trichloroethylene, and benzene) and "sample date". A mixed effects model was used, with agent and date as random effects. Analysis required log transformation of the values recorded in Volume 5 Appendix H-2. The table below shows that, in 3-way ANOVA, concentrations detected in the Priority I homes were significantly higher than concentrations detected in the control home (p <0.039). 3-WAY MIXED EFFECTS ANALYSIS OF VARIANCE PARAMETER Error Variance Constant Type Agent Date ESTIMATE 0.049 0.354 0.053 0.072 0.009 STANDARD DEVIATION 0.003 0.106 0.026 0.039 0.004 P VALUE . 0.001 0.039 - - R&S152100 A 2-way fixed effects model ANOVA was also done to verify that the sample date did not affect the primary factor of interest, "type". The analysis was done separately for the early part of the month (calendar period October 1-14) and the later part of the month (calendar period October 15-29). The second factor in the analysis was "agent" (the six compounds detected in the Priority I homes). Benzene was omitted in the 2-way ANOVA because too few data points in the control home precluded its inclusion in the analysis. Values recorded in Volume 5 Appendix H-2 were log transformed for the analysis. The table below shows that, in 2-way ANOVA, concentrations detected in the Priority I homes were significantly higher than concentrations detected in the control home (p <0.006). 2-WAY FIXED EFFECTS ANALYSIS OF VARIANCE FOR ALL DATES COMBINED SOURCE Agent Type Interaction Error SUM OF SQUARES 4.6203 0.4713 0.5490 28.2087 DEGREES OF FREEDOM 5 1 5 462 MEAN SQUARE 0.9241 0.4713 0.1098 0.0611 F VALUE 15.13 7.72 1.80 P VALUE 0.0000 0.0057 0.1117 n 9W cron oN> R&S152103