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EPA/600/6-86/002 May 1986- OEVEIOPMENT OF AOVISORT LEVELS FOR POLYCHLORINATEO BIPHENYLS (PCBs) CLEANUP Exposure Asses enent Group Of rice of Health and Environmental Assessment Office of Research and Development U.S, Environmental Protection Agency Washington, D.C. rt national technical INFORMATION SERVICE U. HinMaalfKniIsT. O<f iCmMMuOKI HONS (Utmtt t/eicivhffnlicnaml *tht prro^amt hda/mta<#rMwfrng/ i M#*t VO- * a. niciriiNTt Acctsuomoio EPA 500/6-86/002 ' 4. TlTLt AAOXUtTITLt Development of Advisory levels for Polychlorinated Biphenyls (PCBs) Cleanup Mav IMA 1 FtAOOMMINO OnOANIZATlON COOI EPA/600/21 f Aurnomi) Seong T. Hwtng, James W. Falco, Charles H. Nauman 1- MMFOAMlNO OAOANiXATlOM A|q*t AO Office of Health and Environmental Assessment (RO-669) Exposure Assessment Group U.S. Environmental Protection Agency Washington, O.C. 20460 It. SPONtOMINO AOSNCY NAMl AWO AOOMtM 10. FH04HAU lloiUftfef fcft* ii tvm or niroMT amo ismioo eovanio same as #9 i*. anowsoniwo Aflame* com EPA/600/21 l*. AWT uct This dociweqt presents background information used in developing advisory level' of PCBs in soil estimated to be permissible In protecting public health. The results of exposure assessment and health effects studies are combined to arrive at the permissible levels of PCBs. Health effects studies conducted using animals for the duration of 10-30 days are used to determine the 10-day advisory levels for PCS clean, up. The long.tens.advisory levels are based on the carcinogenic`risk evaluations. Exposure pathways considered in estimating the 10-day and long-term average daily intakes include soil ingestion. Inhalation, dermal contact, ingestion of contaminated food, and ingestion of water. Exposure to drinking water contaminants is presumed to occur independently of other pathways, becaust water could come from a clean public water system. The exposure pathways most pertinent to the evaluation of permissible PC3 levels in soil are soi, ingestion, .apor inna'scion, and contaminant contact huaan skin. The currently available modeling techniques considered most appropriate within the constraints of availability of Input data are used to estimate exposures. PCB advisory levels are presented as ranges of values to reflect the difference in soll-aipartition coefficients depending on soil type, different types of coeewrclal Aroclors, and variations In the soil Ingestion rate. it. tv monos and oocumsmt AMtvme fc.lMNTIPlim/OPtll IMOlOTlIlia c eOSAT! FiaM/Cnur II. a'TAiuTIO** STATIMSNT Release to the public ._ is. cviaity cwam enut nwn Unclassified 10. itcuAiVv CkAia rnttmtt/ Jncltssifieo ii. **& o* 216 ii iel - ) MOMS 224377 DISCLAIMER This docjnent has been reviewed in accordance with the U.S. Envlrormentel Protection Agency's peer and admlnistratIve review policies end approved for publication. Mention of trade names or conmerclal products does not constitute endorsement or reconnendetlon for use. 11 MOMS 224176 CONTENTS Tables...................................................................................................................... Foreword............................................................................................................. vii Preface..................................................................................................................... lx Abstract............................................................................................................. * Authors and Revfewers...................................................................................... 1. Executive Summary.............................................................................................. xi 1-1 Z. Introduction...................................................................................................... 2-1 ]. Chemical Compositions...................................................................................... ]-l 4, Production........................................................................................................ 4-1 5. Uses.................................................................................................................... 5-1 (, Disposal............................................................................................................. 6-1 7. Chemical and Physical Properties.............................................................. 7-1 8. Environmental Distribution ......................................................................... 8-1 9. Environmental Fate and Transport .............................................................. 9-1 10. Toxicology....................................................................................................... 10-1 11. Existing Standards and Guidelines , ..................................................... U-i 12. Exposure Assessment Methodology................................................................. 12-1 12.1 12.2 12.3 12.4 Estimation of Exposures for Contaminated Sites ...................... Determination of Permissible Pollutant Level In Soil . . Incorporation of Time-Varying Parameters ............................ PCS Advisory Evaluations........................................................... 12-3 12-10 12-11 12-14 13. Hater Quality Limits.................................................................................... 13-1 14. Leachate Contamination of Groundwater..................................................... 14-1 15. Soil Ingtstlon Pathway................................................................................. 15-1 111 MOMS 224379 CONTENTS (continued) 16. [nhalttfon Pathway......................... ........................................................ 16.1. 16.2. 16.3. 16.4. Intake by Air Exposure Route.................................................. Emission Evaluation Scenarios ............................................... Air Dispersion Modeling........................*.............................. Air Exposure Evaluation.......................................................... 17. Dermal Contact Pathwey .......................................................................... 18. Comparison of Exposures by Soil Ingestion. Inhalation, and Dermal Contact ......................................................................................... 19. Results......................................................................................................... 19.1 Derivation of Permissible Soli Contamination.................... 19.2 Suimary of Results ...................................................................... 20. Limitations of Application ........................................................ 21. References.................................................................................................... APPENDICES A. Models Used In Air ReleaseRate Calculations.................................. 6. Example Emission Rate Calculations for Four Studied Scenarios................................................................................................... C. Siimary of Computer Runs for Each Aroclor and at Each value of Soil-Air Partition Coefficients ....................................... D. Health Advisories for PC8s In Soil (Prepared by N.l. Dourson. Environmental Criteria *nd Assessment Office, Cincinnati, OH) ........................................... 16-1 16.1 16.2 16_g 16.iq 17.1 18*1 19-1 19-1 13.a 20-1 21-1 A-i B-l C-l 0-1 1v MOMS 22*360 TABLES 1. Permissible PCS soil contamination levels (uncovered surface contamination)............................................................................. 2. Permissible PCB soil contamination levels (25-cm-thlek clean cover).................... 3. Approximate composition of Aroclors ................................................... 4. Chemical and physical properties of PCBs........................................... 5. Solubility of chioroblphenyls In water............................................... 6. PCB monitoring In ambient air by NY50EC........................................... 7. Existing PCB standards and guidelines ............................................... B. Maximum lifetime risk for ingesting soil contamination at different PCB levels.......................................................................... 9. Maximum dally PCB intake by ingestion of soil at various PC8 concentrations .............................................................. ID. Comparison of PCB Intakes by Ingestion and Inhalation routes for acute effects.......................................................................... 11. Comparison of PCB Intakes by Ingestion and Inhalation routes for carcinogenic effects .......................................................... 12. Concentration of PCBs In soil at saturation vapor pressure based on Kg 1,000 an*/g....................................................... '.2. PCS. frzr, I ,*3/3 PCB sell it different control levels............................................................................................. 14. Values of constants for standard deviation expression as a function of downwind distance and stability condition .... 15. Ambient PCB concentrations at different locations (PCB In soil 1 u9/9. W8-12S4).......................................................... 16. Caparison of Intakes by various exposure routes............................ 17. Evaluation conditions for each Aroclor............................................... 18. Low and high values of air-soil partition coefficient used In the evaluation...................................................................................... l_g j.; 3.3 7.3 7.5 9.3 11.3 15-1 15-2 16*3 16-4 16*7 16-7 16-10 16-11 18-1 19-5 19-6 4 HOMS 2243S1 19. Permissible PC8-1242 soil contamination levels (uncovered surface contamination)..................................................... ....................... 20. Permissible PC8-1Z40 soil contamination levels (uncovered surface, contamination). ............................... ...................... 21. Permissible PCS-1254 soil contamination levels (uncovered surface contamination)............................................................................. 22. Permissible PCB-1260 soil contamination levels (uncovered surface contamination)......................................................... 23. Permissible PCS-1242 soil contamination levels (25-cm-thlck clean soil cover)..................................................................................... 24. Permissible PCB-1248 soil contamination levels (Z5-c*th1ck clean soil cover)..................................................................................... 25. Permissible PCB-12S4 soil contamination levels (Z5-c*thlck clean soil cover).......................... 26. Permissible PCB-1260 soil contamination levels (25-cm-thlck clean soil cover)......................................... 19.7 19.5 19-9 19-10 19-11 19-12 19-13 19-14 vi MOMS 224382 FOREWORD Tn Exposure Assessment Group {EAG) or EPA's Office of Research nd Development has three main functions: 1) to conduct exposure assessments; l) to review assessments and related docuaents; and 3) to develop guidelines for Agency exposure assessments. The activities under each of these functions are supported by tnd respond to the needs of the various ERA program offices. In relation to the third function, EAG sponsors projects aimed at developing or refining techniques used in exposure assesmnents. and at applying these techniques to develop health-based advisory levels for contaminant cleanup. This docunenc is one of these projects and was done for the Office of Solid Waste and Bnergency Response. Polychlorinated biphenyls (PCBs), commercially known as Aroclors, consist of mixtures of chlorinated biphenyl compounds. Many sites contaminated by PCBs remain contaminated because of PC8 persistence In the environment. Although comnerclal PCS production has been banned by the Toxic Substances Control Act, continued use in previously existing commercial equipment can result in splits which require cleanup. EPA has become Increasingly Involved In the discovery, assessment, and cleanup of these Sites. The purpose of this docuaent Is to provide advisory levels for PCS cleanup, and to describe the detailed technical and scientific rationale end methods used In developing these advisory levels for PCBs In contaminated soil. This project required development of exposure and risk assesment methodology related to hazardous waste and spill sites, and analyses of health effects data. Tha advisory levels and the assessment methodology thus developed will help EPA set vi1 MONS 224383 priorities In PCS spill and cleanup management, and address ocher PCS contaminant problems. Michael Callahan, Director Exposure Assessment Group HONS 22*384 will PREFACE The Exposure Assessment Group of the Off tee of Health and Envlronmental Assessment (OHEA) has prepared this development doctaaent for advisory levels for polychlorinated biphenyls (PC8s) cleanup at the request of the Office of Emergency and Remedial Response. This document s Americas the procedures concerning multlmedfa exposure assessments for PCI-contaminated sites, and literature Information on chemical and physical properties and healtn effects pertinent to evaluation of exposures to PCBs. The purpose of thfs docunent is to serve as a technical and scientific basis for developing healthbased advisory levels for PCBs in soil at spill or cleanup sites. The literature search supporting this docment is current to Nay 1986. HONS 224385 abstract This dociment presents background information used In developing advisory levels of PCBs in soil estimated to be permissible in protecting public health. The results of exposure assessment and health effects studies are combined to arrive at the permissible levels of PCBs. Health effects studies conducted using animals for the duration of 10-30 days are used to determine the 10-day advisory levels for PCB cleanup. The long-term advisory levels are based on the carcinogenic risk evaluations. Cxoosure pathways considered in estimating the 10-day and long-term avertge dally intakes include soil ingestion, inhalation, dermal contact, Ingestion of contaminated food, and Ingestion of water. Exposure to drinking water con taminants Is presuaed to occur independently of other pathways, because water could come from a clean public water system. The exposure pathways most per tinent to the evaluation of permissible PCB levels In soil are soil Ingestion, vapor inhalation, and contaminant contact with human skin. The currently available modeling techniques considered most appropriate within the constraints of availability of input data are used to estimate exposures. PCBs advisory levels are presented as ranges of values to reflect the difference in soil-air partition coefficients depending on soil type, different types of commercial Aroclors, and variations In the soil Ingestion rate. X MOMS 224386 AUTHORS AND REVIEWERS Th Exposure Assessment Group of the Office of Health and Envl romnental Assessment was responsible for preparing this dociment. AUTHORS Seong T. Hwang Exposure Assessment Group Office of Health and Environmental Assessment U.S. Environmental Protection Agency James W. Faico Office of Environmental Processes and Effects Research U.S. Environmental Protection Agency Charles H. Hausen Exposure Assessment Group Office of Health and Environmental Assessment U.S. Environmental Protection Agency REVIEWERS The following Individuals provided review comments and criticisms during several peer>rev1ew processes to which this docusent was subjected. H t ?lr'i;r Office of Toxic Substances U.S. Environmental Protection Agency Joseph A. Cotruvo, 01 rector Criteria and Standards 01 vision Office of Drinking Water U.S. Environmental Protection Agency Voram Cohen Department of Chemical Engineering University of tlllfomla, Los Angeles Los Angeles, California Barbara Davis Office of Waste Programs Enforcement U.S. Envlronmental Protection Agency MONS 22+387 XI Karen Hammerstrom Exposure Evaluation Division Office of Toxic Substances it.s. Envlrorcnental Protection Agency Krlshan Khana Health Effects Branch Office of Drinking Mater U.S. Envlro mental Protection Agency Bussell Klnerson Office of Toxic Substances U.S. Environmental Protection Agency Will lam Marcus Office of Drinking Water U.S. Envlronnentel Protection Agency Robert E. MeGaughy Carcinogen Assessnent Group Office of Health and Environmental Assessment U.S. Envlronsental Protection Agency Mary Lund Mortensen Agency for Toxic Substances and Olsease Registry Atlanta. Georgia Debdas Hikerjee Environmental Criteria and Assesseent Office--Cincinnati U.S. Environmental Protection Agency Judith A. Nelson, Director Regulatory Coordination Team Office of Pesticides and Toxic Substances U.S. Environmental Protection Agency Arnett Nold Office of Toxic Substances U.S. Environmental Protection Agency Edeerd V. OhanIan Health Effects Iranch Office of Orlnklng Hater U.S. Environmental Protection Agency Suresh Rao Soils Department University of Florida Gainesville, Florida Danny Relble Department of Chemical Engineering LoultUna State University Baton Rouge, Louisiana Charles Rls Carcinogen Assessment Group Office of Health and Environmental Assessment U.S. Environmental Protection Agency - Jerry F. Stara Environmental Criteria and Assessment Offlee*Cincinnati Office of Health and Environmental Assessment U.S. Environmental Protection Agency Louis Thibodeaux Hazardous Waste Research Center Louisiana State University Baton Rouge, Louisiana Edwin F, Tlnsworth, Oeputy 01 rector Office of Toxic Substances U.S. Environmental Protection Agency X 111 NOBIS 22*389 1. EXECUTIVE SUMMARY This report hes been prepared In response to a memortndun deted April 9, 1985, from the Office of Emergency end Remedial Response (OERR), requesting that the Office of Health and Environmental Assessment (OHEA) develop advlsory levels for polychlorinated biphenyls (PCBs) which can be used es guide lines for initiating removal action for sites contaminated with PCBs. Inter ested offices within EPA, Including OERR, have advised OHEA that these advisory levels for PCBs cleanup should be developed based on considerations of public health protection from short-tern and long-term exposures. The advisories presented In this report Include permissible levels of PCBs in soil correspond ing to 10-day and lifetime acceptable Intakes, Exposure routes considered In developing these advisory levels Include drinking water, ingestion of PCB-contaminated soil by children and adults, and inhalation of ambient air contaminated with PCBs. Other exposure routes, such as dermal exposure, food Intake, and Ingestion of fish which have bloaccumulated PCBs, are considered In relation to their Importance and their relevance to the present document. In view of the high bloaccumulatlon factor for PCBs, the consideration of bloaccumulatlon Is Important In setting PCB levels In surface water In which aquatic animals live. If one of these routes Is a controlling factor In relation to the exposure route or human Intake considered, the advi sories need to be reevaluated. Commercial-grade PCBs marketed as Aroclors in the United States are mix tures of many chlorinated biphenyl compounds In various proportions. Each PCB compound may exhibit Its own toxicological characteristics and physical and chemical properties. This fact complicates the exposure analysis In deriving the allowable concentrations In drinking water and soil. It Is conceivable 1-1 MOMS 22+390 I that chemical and physical properties reported in the literature for eacn Arodor designation represent an average property for the mixture. To define* the variability of safe levels for contamination by different Aroclor designations, exposure analyses have been performed for several Aroclors: Aroclor 1242, 1248, 1254, and 1260. The steps used in developing the advisories Include: (1) the evaluation of toxicological effect studies. (2) exposure analysis for PCS intake from drinking water, soil Ingestion, air Inhalation, and denial contact, and (3) risk assessment combining the toxicology studies and exposure analysis. Ten-day noncancer health advisories are based on the short-term acceptable intake (Al) derived from studies of animals treated with Aroclor-1254 for no more than 30 days to examine noncarclnogenlc effects. This AI value, which forms the basis for establishing permissible levels of PCBs In soil. Is 0.1 and 0.7'mg/day for a 10-kg child and a 70-kg adult, respectively. The permissible PC8 concentrations for each carcinogenic risk level are based on the potency factor of 4 (mg/kg*dayJ*1 rounded off from two Independent evaluations based on an Aroe lor-1260 study. It Is likely that not all of the PCBs Ingested or Inhaled by humans are absoroeo. Proper calculations of absorption rsts ini hsrej ir.pttur* based on realistic, pharmacokinetics-type. models to determine intake. Lack of experimental data with which to estimate the parameters needed In the pharmaco kinetics models has prevented their applications to the analysis for PCB absorp tions through human exchange boundaries. Future work should consider these models. Although most animal studies (In rats and mice) on the extent of absorption In the gastrointestinal tract show absorption In excess of 90S, there are two experiments on monkeys reporting less than 881 absorption In one case and less than 131 and 401 absorption for a specific congener In another case, based on the analysis of feces and urine. Vehicles used In administering 1-2 MOMS 224391 PCBt were not specified. It is likely that the high adsorption characteristics of PCBs on soil could retard the adsorption rate in the hunan intestinal tract. In the risk analysis performed fn the present study, the absorption rate for humans after Ingestion of PCB-contamlnated soil Is considered to be 30X. Absorption from dermal exposure has been reported to be as significant as from other routes of exposure, but little information Is available for the quantitative evaluation of dermal absorption rates. Five percent dermal ab sorption is assimd for soil contaminants In contact with himan skin. The dermal absorption rate of contaminants present on soil Is presumed to be less than that for contaminants spilled on skin In pure form. Inhalation studies using PC8 aerosols show that the absorption of PCBs from inhalation exposure readily occurs. In the present analysis, an absorption factor of SOI Is assuied for absorption of PCB vapors after InhaUtlon Into huaan lungs. The clrcunstances under which hiatan exposure occurs are divided Into three classes depending on population distribution: (1) Exposure occurs on-site. This can be further subdivided into: (a) sites which are readily accessible to children, and, hence, the soil from which will be subject to Ingestion, der mal contact, and inhalation, and (b) sites for which there Is no possibility of soil ingestion, and, hence, exposure is only through inhalation; (2) sites which no population Is assueed to enter within a radius of 0.1 km from the site; and (3) sites which no population Is assueed to enter within a radius of 1 km from the site. The soil fhgestlon rates used for Class (l)(a) evaluations are 3 and 0.6 g/day. The former is a value based on data fro* a study of an adult person with pica, while the latter represents a long-term average value for soil ingestion. If sites are not accessible to populations at distances of 0.1 ion or 1 km from the site, as in Classes (2) and (3) above. It Is assuMd that 1-3 MOMS 22*B92 no ingestion of contaminated otl occurs mo the exposure route is that of Inhalation. The emission rate of volatilized PCSs can be considerably reduced by covering '.he contaminated soil by lOw-porostty uncontmxlneted soil Or clay material. The reduction In the emission rate will result In a decrease In ambient air concentrations of PCBs by the action of blowing winds. When pcbcontamlnated material Is directly exposed to the atmosphere, the PCS levels in soil required to maintain the same level of exposure will be less than those expected when the PCB-contaminated material Is covered with low-permeablltty material of appropriate thickness. The cover would also serve as a deterrent to soil Ingestion and direct dermal contact. The depletion of PCBs from soil caused by volatilization Is accounted for In the exposure analysis by solving a partial differential equation simulating PCB vapor diffusion through the soil air-phase pores, and the distribution of PCBs between air and soil phases. Boundary conditions assuee that tht air.phase resistance is relatively small compared to the dlffuslonal resistance in the soil air-phase pores. The available experimental data reasonably follow the time-amission rate reiationsnip preoicteo fra tne moo*Is oased on this assump tion. Since the depletion rate varies over time, it Is averaged over theexposure period. Depletion averaged over a period of time should lead to a lesser inhalation exposure than that based on the model assuaing that depletion does not occur. The worst-case amissions would occur when the contaminated soil is initial ly exposed to the atmosphere and the soil is contaminated up to the conditions exhibiting saturation vapor pressure. A constant amission rate can be assuxed if the vapor-phase concentration maintains a constant value at the surface of 1-4 HONS 224393 soil contiminotion for time-varying omission rates. Calculations corresponding to Classes (1), (2), and (3) for exposure possibilities with surface contamina tion are repeated at an assumed 25-cm thickness of a soil cover Initially free from PCS contamination. Among many factors affecting thw emission rate (In cluding vapor pressure, soil-air partition coefficient, Henry's Law constant, etc.), the value of the soil-air partition coefficient shows the most wideranging variation, because of the variation of the experimental soil-water partition coefficient available In the literature for soil textures ranging from 40 to 1,000 cnVg. The method for determining the permissible PCS levels In soil, which com bines the routes of soil Ingestion, Inhalation, and dermal exposure, has been computerized to avoid the necessity for hand calculations. The results of these computer calculations are suamrlzed In Tables 1 and 2, which have been prepared using different combinations of the following varlablas; (1) Surface contamination representing a situation where the contaminated soil surface has been left uncovered after removal action. !2) 2S-c (10-Inch) clean cover applied, representing a situation Jr which clean soil material Is used on top of the. contaminated soil surface. (3) Two different soil ingestion rates (3 and 0.6 g/day) for Class (l)(a), corresponding to sites accessible to children. (4) Different AI levels (short-term AI, and AIs at different cancer risk levels). (5) Pour Aroclors (Aroclor 1242. 1248, 1254, and 1260). (6) Two selected values of the soil-air partition coefficient, repre senting the high and low values. MONS 228394 IMIf 1, KKIMSSIM.E *C4 SOIL CONNUMMIIM LEVELS (UNCOVflEO SUVACC CONIMtlMIIONl location and roata af haaaa atpatura f>iriiilH> twli 1h Wl/t tall I cvrmtirtli^ u Aaacaacar thari -tara* accaatahla lataka InO/davl* Caacar rltk waclEtc datai (na/divt 100 far chili rao fti adult 0.001 (10-f rltk) o.om (It*4 rlU) 0.1 ft (10-* rltk) (l*-V4 4rltk) on tba caataaiaatad tlta - Sail 1 natation*, lahalatlaa* tS-loo' - Sail 1natation*, lahalatlaa* 41-410 > lahalatlaa anIf4 41-nl SiO-JJO 1.00.3000 n 0.000-0.01 0,01-0.00 O.0I-O.1 .00-0.1 O.l-O.t 0.1-1.0 0.0-1 1-4 1-10 l-lf JS-tl II-4J0 0.1 ka fraa caataninatad tita - lahalatlaa anIf* 1 ka fraa MlMlMIU lilt - IriuUilM wl|* n n n i.o-na (O-l.ZalQ* r.inoi-tt t.fil0A-Tt no-i.iiio^ I,lil0*-l.)tl0* tl n * Short-t ara a 10-day tatHa. *taiai aa ataraaa aalahtt af 10 and JO f tar a child and aa adalt, ratoactltaly. `Cbtidraa aaat l-S, with atca (cantualaf 1 tall/day). *Chlldraa aaat l-S, althart alca (cantwin* 0.0 f tan/day). inhalation ratat ara attaad (a ha 70 a*/4w Ear tba thart-tara mV lanonr-tara aaacaacar aanaturat; all aihtr |ara chraalc) tiaoiarat atMaad ta ha 10 a'/aajf at a ratal! af 107 dnya' aanatara oar yanr. flaaat ratal! la aach cata hacaata I) faar KOi (lt*2, 1140, IIM, IMO) ara cansldarad, aach alth a airfaraat tayar arattara, mV t) h1#i aaV taa aalaat far tall-air partition caafflclant ara aach la lha calcalailaaa. *vt taaataa aa thaaratital ufvr-taiaV Halt. Ortctlcal raataat raaalra aa Eraa-flaalaf NO Hautot far tba Halt. MOMS 22*393 imu !. KMissiau w (?-<-thlct CsUilMm(tmillh)wim umt ftftnim laaaH I-- tt/t mil carrapaMtaa ta Lacatlaa u< raa<a it kwa KCWtOU latatt <ri/wl ioa hal far cal ltf far -halt cwtf Mat taatwu <**f*t (aa/aw) a.pm a.am (ia-'rMnat) (* rlal t) {.MIffat) (!"y trfak) Oa tat caataaiaatai ttta - tall laftatlaaC. lakalatlaa* - tall lapttlta*. lakalatlaa* . lakalatlaa aaly* 11 n IW Sl*u-n ti I.IH.1 a.tf-i.a i.i-i.a .f-tt l-lf f.l-n ?!-n M-n lft-n l.l ta fraa taataalaatP tlta lahalatlaa ply* I tataMfaraa*luiM tlta lahalatlaa aal|* n n n n Un <N>n nn nn nn NlM aa aaaraaa aalMt aJ aa la k far a cMM aaf aa adult, rapact Italy. *cailaraa taaa 1-t. wlta pica (caaatMai 1 a tall/dtrl* *Chl Iart ip i-i, vtthaat |tu (taaaaataf a.a a aal l/day). lakalatlaa rata* art aaaaaai U ha far Ua IkartHM mt iPpr-ttfk aaacaacar aapaaarat; all attar (art ckratlc) aaaaiaraa atpap ta ha 1C */da aa a raaait af l*t tayi' aaaaart aar par. 'lap raaait la aacb cap tactaaa 11 faar fCta (1MI. ISt, IIP, tttt) art caaatdara4, tact altfi a dlffaraat tap arattara, aal 1) hip aa4 | talaaa far aall-alr tartIt la cpff Ictaat art tap la tha calcatatlaai. **t taaataa aa ttaaratlcal apar-taaP HPt. Practical rattan rapIP aa fraa-f laataf PCI llplt* far tha lint. MOMS 22*396 (7) Exposures for 10 days after cleanup or spill of contaminants for short-term advisories. Table 1 shows the range of values for permissible PCB concentrations In soil when the soil Is contaminated up to the surface In contact with the atmo sphere and is left uncovered. Table 2 represents the case where the contami nated soil left at the site, or after remediation, Is covered with a 25-cm (10-inch) clean soil layer. The ranges In both tables result from the use of four Aroclors and the use of high and low values for the soil-air partition coefficient. Other factors reflected In the ranges are differences In vapor pressures and Henry's Law constants for each Aroclor. The permissible PCBs levels In soil specific to each comolnatlon of the scenarios are compiled in Appendix C, as obtained from computer simulations. The symbol "vs" In Tables 1 end 2 Indicates that no upper-bound limit for PCB concentrations In soil can be derived from the exposure evaluation, because the PCB concentration In soil Is above the vapor saturation concentration. There are two reasons for such a result. First, the emission rate cannot exceed the upper-bound value which can be expected when the air-phase concen tration of PCBs at the contaminated soil surface Is maintained at the vaoor saturation point. The concentration at the vapor saturation point corresponds to the vapor pressure concentration. Second, when the cover Is applied, not only Is the emission rate retarded, but also the concentration of PCBs In soil being Ingested Is controlled by the amount of PCBs adsorbed on soil In equlli brium with the air pibase being emitted. Therefore, the concentration of PCBs In the Initially clean soil material cannot exceed the concentration In equi librium with saturated vapor. In actuality, the "no upper limit," or the level above vapor saturation, designated by vs, should be Interpreted with great care. The assumptions used i-a WINS 224397 in tne exposure evaluation are critical. They include Out are not linnt*a to: (1) no soaking of clean cover by liquid PCBs for the thickness of 25 cm; (2) no disturbance of cover material oy construction activities or children digging the ground; (3) no exposure to initial spills when 25 cm of clean cover (Table 2] is assumed; (4) no population enters the area within the respective radius of distances from the site; and (5) the cover material Is at least equivalent to soil material. From a practical point of view, Assumption 1 Is tantamount to requiring the presence of no free liquids In the soil, which may otherwise result in the phenomenon of "wleking," Since the ranges shown In Tables 1 and 2 are depend ent upon the type of Aroclors and the values of the soil-air partition coeffici ent, site-specific or Aroclor-speclflc Information should be used to establish an appropriate level of PCBs for that particular condition. The methodology for performing site-specific exposure evaluations Is presented. Computer outputs for the selected Aroclors under the ranges and conditions of cannon environmental concern are presented In Appendix Ct and can easily be used to find the permissible concentrations In soil suitable to particular situations. Table 1. for example, can be Integrated as follows: (1) When the site Is amenable to access by children with possibilities of Ingesting the-contaminated soil exposed to the atmosphere, and when exposure occurlng to the children by Inhalation and dermal contact is accounted for, the permissible PCS levels In soil should range from 25 to 100 ug/g and 42 to 420 ug/g for prevention of noncancer effects from 10-day exposure for a child with an average weight of It) kg Ingesting soil at the rates of 3 and 0.6 g/day, respectively. For cancer effects, permissible levels In soil for a lifetime exposure to PCBs resulting from Ingestion of and dermal contact with contaminated toll and Inhalation of contaminated air should range from 0.08 to 0.1 ug/g 1-J NONS 224390 and 0.1 to 0.6 ug/g, corresponding to an upper.bound risk estimate of iu* at assuned soil ingestion rates of 3 and 0.6 g/day, respectively. The specific level will depend on tne types of Aroclor present, the likely Ingestion rate, and the extent of soil-air partitioning. For sites In which there Is no possi bility of soli Ingestion, PC8 levels In soil, based on the Inhalation route only, should range from 47 g/g tono limit value for a 10-day exposure for a child with an average weight of 10kg, and correspond to no limit value for an adult with an average weight of 70kg. The permissible levels of PCBs In soil, based on the Inhalation pathway only, rangefrom 0.1 to 2 gg/g, corresponding to a lifetime At at a risk factor of 10*. Again, the level will be dictated by the types of Aroclor present and the specific characteristics of tne site invol ved. (2) If there Is no possibility of a population entering the contaminated site within a radius of 0.1 km from the site, the PCS levels In soil can remain at no limit value and 90 to 2.2 x 104 gg/9, without exceeding 10-day A! and lifetime At at 10* risk, respectively. Similar Interpretations can be made for the results applicable to sites ..'.t'.c.t ;cpvliticr, up to 1 km from the site, and to the carcinogenic risks listed at 10*4. 10*5 and 10-7. The short-term A1 levels (100 pg/g day for a child and 700 gg/g day for an adult) used In this report to develop 10-day advisories based on noncancer effects are derived from animal studies, which collectively indicate that the experimental threshold for adverse effects of Aroclor 1254 is at or near a dose of 1.0 pg/kg body weight. Using this dose as a No Observed Adverse Effect Level (NOAEL) and a safety factor of 100, the 10-day AI levels for non cancer effects described above (100 and 700 gg/day) were confuted and serve 1-10 MOMS 224399 Advisory levels for 1-oay ana lifetime noncancer effects cannot be aerived 4t this time because of the insufficiency of the available data. However, in view of the experimental duration, the 10-day advisories nay well be used for the 1-day advisories. 11 MQNS 224400 2. INTRODUCTION The purpose of this document Is fourfold: (1) to provide background information compiled In the process of developing permissible health advi sories for polychlorinated biphenyls (PCBs) In soil and drinking water, in response to a request from the Office of Emergency and Remedial Response, (2) to outline the procedures used In developing the advisories, (3) to list per tinent input data necessary In carrying out the exposure analyses and In set ting the allowable concentration limits, and (4) to present an outline summary of the results obtained from computer simulations of th techniques used. The information and methods presented are Intended for use In setting safe advisory levels to protect public health from short-term, longer-term, and lifetime exposures to PCBs released from hazardous waste facilities or from spills at previously contaminated sites. Particular Interests pertain to levels of PCBs allowable In contaminated soil, and the potential of PCS migra tion to groundwater from PCS-contamlnated or hazardous waste facilities. These advisories are not concerned with setting PCB limitations In sediments contaml- curfic- v.'stsr, ,/hlch can be i source of bloeccumulatlon of PCBs In aquatic animals. Th analyses presented In this report provide the basis for deriving PCB levels allowable In soil and drinking water, which are likely to be primary sources of exposure pathways, PCB problems that may exist In rivers and estu aries because Of contaminated sediments are not dealt with in these analyses. Th analyses mainly address health concerns at hazardous waste sites or at sites with contaminated soil. The primary health impacts considered Include adverse Impacts associated with Ingestion of contaminated soil. Inhalation of ambient air, and dermal contact with the soil. Other exposure routes, such as 2-; MOMS 224401 drinking water, food intake, and Ingestion of bl oaccumul ateo fish art consider ed to the extent that the pathways are relevant. PCBs that have migrated from contaminated sites to various exposure media are evaluated for short-term and lifetime impacts to arrive at corresponding advisory level values. The total dose of PCBs Is obtained by sunning each dose from all major exposure pathways, and Is compared with acceptable Intakes (AI) judged from the health effects Information available In the literature. A longer-term ai considered most appropriate In deriving 10-day noncarclnogenlc advisories Is used In the exposure evaluation. Advisories for protecting against carcino genic risks are similarly derived at various risk levels based on the potency factor. This report Is not Intended to address the achievablllty of the safe levels developed. Although the report contains a brief statement, taken from the available literature on analytical capability, control technology, and environmental distribution of PCBs, the data base seems Insufficient to make a generalization concerning the level of PCB cleanup achievable In practice. The Exposure Assessment Group distributed three earlier drafts of this iacument under the title of "Development of Health Advisories Mr oolyrhlorin. ated Biphenyls (PCBs)" for Internal review and coemnt on Hey 9, 1985 and July 25, 1985, and under the title of "Development of Health Advisories for Poly chlorinated Biphenyls (PCBs) Cleanup" on December 16, 19B5. As a result of the comments from the Office of Orlnklng Water, on the December 16, 1985 draft, the 1-day advisories-have been replaced by 10-day advisories because no data could be found Indicating that S.A.StS'.A'.S'-hexachloroblphenyl, used for development of the 1-day advisories. Is a component In coenerlcal Aroclors. This final draft reflects changes made to Incorporate coemmnts from the Office of Toxic Substances, the Office of Emergency and Remedial Response, and OHEA's Z-l NONS 224402 Envl roiunental Criteria and Assessment Office. 224403 3. CHEMICAL COMPOSITIONS A polychlorinated biphnyl (PCB) 1* eny member In a family of organic compound* with two or more chlorine substitutions on biphenyl ring*, and can be typified by the following chemical structure; xx xx x xx x The symbol, x. In the structural formula represents possible positions of chlorine tht cm be substituted for hydrogen, which Is one of the basic ele ments of aromatic hydrocarbons. Based on the possible distribution of substi tuted chlorine atoms on two benzene rings of biphenyl, It Is calculated that there could theoretically be 209 types (congeners) of PCSs. Patents disclose that PCBs are prepared by the chlorination of biphenyl In the presence of a catalyst. The process yields a complex mixture of chlorinated biphenyl compounds. It Is unlikely* however, that all combinations of chlorinated biphenyls would be formed In the chlorination process. Although the crude mixture Is purified to remove reaction Impurities, the resulting product Is still a mixture of chlorinated biphenyls In various proportions. Their compositions depend upon the chlorination conditions. Commercial-grade PCSs, consisting of mixtures of different composition, are sold under the trade name Aroclors. Impurities such as chlorinated dlbenzofurans and chlorinated naphthalenes are known to exist In commercial PCSs. The sole producer of Aroclors in the United States for the period 1957 to 1972 was the Monsanto Chemical Company. Their products are characterized by four-dlgn numbers. The first two numbers represent the type of molecule (12 blphenyi- 3-1 MONS 224404 based; 54 terphenyl-based; 25.44 * blands of PCBs and chlorinated terphertyis; and the last two digits refer to the-percentage of chlorine by weight. PCB products are also manufactured in otner countries, Including Germany, France, Japan, and the U.S.S.R. Table 3 Illustrates approximate compositions of Individual biphenyls for some Aroclors (U.5. EPA, 1976b). Although one might expect some 140 to 150 separate congeners In an Arodor, the actual analysis of Aroclor 1246, for example. Identified less than SO peaks In the high-resolution gas chromatograph using a typical Aroclor 1248 sample {U.S. EPA, 1976b). No compounds which can be formed by addition of chlorine rather than substitution were found In a detailed study of PCBs (U.S. EPA, 1976b).' It Is suspected that the conditions prevailing during Industrial manufacturing of PCBs do not favor the formation of addition compounds, or that these latter confounds might have been destroyed In the step used to purify the Aroclor. In constrest to the analysis shown In Table 3, another publication reports an analysis of Aroclor 1221 to contain 12.7* biphenyl, 47.lt monochlorophenyls, and 40,2t dlchlorophenyls (Hutilnger at al., 1974). Major ?CB components In foreign product! Ssirl" t^s rises ?f ''anech'or ahd Phenoclor for Japanese, and.French products, respectively, have been identlfled. The number of the major components separated from Kanechlor 400 is five, and that from Phenoclor OPS is seven. 3-2 MOMS 224405 TABLE 3. APPROXIMATE COMPOSITION OF AR0CL0R5 CM o rob < phenyl C12H10 C12M9CI C12*<8C12 Cl27c13 Cl2*<6cl4 CizHjCls c12h4^6 c12h3c17 Ci2H2C18 c12m1c19 Cl2C110 NO non-d*t*ct*b1*. Percent by weight for Aroclor d**1gn*tlon 1221 1242 1248 1254 1260 1016 11 <0.1 51 1 32 16 2 4 49 IB 2 25 40 0.5 B 36 NO 1 4 NO <0.1 NO NO NO NO NO NO <0.1 <0.1 0.5 1 21 48 12 23 3B 6 41 NO B NO 1 NO <0.1 1 20 57 21 1 <0.1 NO NO NO NO 3-; NONS 224406 4. PRODUCTION Commercial production of PCSs from the starting material benzene was begun in the 1920s by Swann Research, Inc., of Annlngton, Alabama, which referred to these products under the trade nme Aroclor. PCBs were manufactured at that location by Swann Research, Inc., and its successor, Monsanto Chemical Company, until the plant was closed In 1971. Monsanto continued production at another plant at Sauget, Illinois, until 1977, The only other known manufacturer of PCBs is Geneva Industries of Houston, Texas, which manufactured PCSs from 1972 through 1974. The domestic sale of Aroclor products peaked to 33,000 metric tons In 1970, and has declined since then due to restrictions on the use of PCBs (Hutzlnger et al., 1974). PCBs were available commercially as mixtures (Aro- clors) of 20 to 75 chlorinated biphenyls, and were marked according to the weight of chlorine contained In the mixtures. These commercial mixtures 1n- eluded Aroclors 1242, 1254, 1248, 1260, 1262, 1268. 1221, 1232, and 1016, In descending order according to domestic sales. In the year of peak production, :7t of che Aroclors produced were In the form of Aroe'?* '.2*2 'ann*' The production In Japan and the annual consumption in Finland are estimated at 26 million pounds and 0.5 million pounds par year, respectively. PCS*1016 (413 chlorine) Is a more recent product, and Its sales prevailed for the period 1972.1976. PCSs may be tormed as side-products In othar manufacturing processes In. volvlng the use of chlorinated benzene or biphenyl in the reaction step. For example, some of the trlchlorobenzene used as a solvent In the manufacture of the dry pigment phthalocyanlne blue Is converted to PCBs during the reaction. PCBs formed can contaminate the pigment product at concentrations from a few 4-1 MOMS 22++07 parts per million to as muen as O.lt, Similarly, dlehlorobiphenyl is formed In the manufacture of dlaryllde yellow pigments as a product of side reaction with the reactant dlchlorobenzldlne. The process of chlorinating water which contains biphenyl In a compound used as a dye carrier In dyeing polyester fibers can form PCBs as a side-react Ion product which can contaminate the water. No natural sources of PCBs have been Identified, PCBs have been Imported Into the United States for use In various applica tions. Oecachloroblphenyl was Imported from Italy for use as a wax filler In the Investment casting industry until 1976. PCBs Imported from France are used In mining machinery cooling systems. The percentage of imported PCBs over the total domestic sales for the period 1971 through 1975 In the United States Is In the range of 1.6X to 2.7X (U.S. EPA, 1976b). 4-2 MOMS 224408 5. USES Products containing PCBs hava been usad In agriculture and Industry for dacades. Their use is are mainly attributable to high chemical stability and physical properties desirable In certain applications. These properties include nonflamiability, high dielectric constant, plasticizing capability, and ease of volatilization under heated conditions. Since 1930, PC8s have been extenslvely used as dielectric fluids in electrical transformers and capacitors, and have also been used for a variety of other purposes. Including use In heat transfer and hydraulic systems. In the Investment casting Industry, and as plasticizers and solvents In sealants and adhesives. PCBs are also used as flame retardants In the manufacture of hard plastic products In which heat resistance Is desired, as a dye carrier In carbonless copy, paper, and as a plasticizer In paints. Several published sources provide a comprehensive breakdown of uses for different types of Aroclors (Hutzlnger et al., 1974; Nlsbet and Saroflm, 1972; Versar, Inc., 1977). The most widely used Aroclors were 1242, 1248, 1254, and 1260, Aroclor 1016 was used after 1970.but In much smaller quantities than the four types mentioned above. A Monsanto martetlng bulletin on PC8s, published In the 1960s, also described their possible use as gaskets and packing materi. als; as vehicles In graphic arts; as Impregnation agents; as moisture-proof coatings; as wax substitutes; as de-dusting agents; In Insecticides; In abra sives, lubricants, and cutting oils; In Inks; In mastics; and In tank coatings (Monsanto Chemical Co., undated). A number of other uses have been patented. In the United States, there are 17 companies that have used PCBs in the manufacture of askarel capacitors, and 13 companies that have used PCBs in the manufacture of askarel transformers. According to one study, in 1976 approxi- S-l MOMS 224409 mately 25 Investment casting foundries (out of total of 135 in the united States) used PCB-fllltd waxes in the manufacture of metal castings (U.S. PA, 1976a). In 1971, because of environmental concerns, the manufacturer voluntarily restricted the sale of PCS products for use only In "closed" systems, which include electrical transformers and capacitors with Insulating fluids that contain PCBs. These two applications account for all of the current use of PCBs in the United States. The company was on a schedule to phase out pro* ductIon of all PCBs by 1979. The cessation of the production will reduce the amount of PCBs being released Into the environment, but millions of pounds of PCBs are still being used In electrical insulation applications. The environ mental contamination by existing PCBs, and their environmentally safe treatment or disposal, continue to be of concern. *OMS 224410 S. DISPOSAL A material balance performed on the amount of PCBs produced, sold, ana purchased provides an estimate of the amount of PCBs lost or disposed of In the manufacturing process. The total estimated amount reported to have been disposed of or lost for the year 1974 is about 3.8 million pounds (U.S. EPA, 1976b), of which about l.B million pounds are estimated to have been land* disposed, and the rest to have been Incinerated. The 1.8 million pounds of PC8s In the land-disposed wastes generated from the manufacturing process amounts to only a small fraction of the total PCBs sent to land disposal facilities. The total land-disposed amount of PCBs for the year 1976 is reported to have been about 12 million pounds (U.S. EPA, 1976b). The most Important source of PCB waste has been capacitors that have failed or become obsolete, or that are contained In obsolete equipment. Other PCB wastes Include solid wastes from PCB manufacturing facilities and from operations using PCBs In nonelectrical applications. The data base for the WET Model, prepared by SCS Engineers (Undated), shows :.hst PCS fluids cthtilnlrs *0?, PC2-12S4 Tint hsz!rdous waste treatment, storage, and disposal facilities (TSOf) amount to about 4,500 tons per year. This waste competes for the capacity of TSOF regulated under Subtitle C of the Resource Conservation and Recovery Act. Water effluents from PCB production and first-tier use faclltles are relatively small compared with the amounts being disposed of In landfills. Severe local Impacts are evident by the dlscharge into rivers of these effluents. PCBS are now found in the sediments, water column, and biota In the rivers, A few examples of current PCB problems Include the Hudson River and the New Bedford, Massachusetts, harbor. As a result of a strong tendency of PCBs to adsorb on sediments, and of sediment 6-1 MOMS 224411 migration, pcs problems are identified farther downstream from the discharge points. Twenty spills Involving PCB products have been identified (Lt.S. EPA, 1976c). These spills occurred In transformer Installations from trucks and railroad cars while they were en route to their destinations, and from leak in drums. 6-2 MOJSS 224412 7. CHEMICAL AND PHYSICAL PROPERTIES The chemical and physical properties of PCSs can be divided Into two groups: (1) those relevant to the commercial and Industrial use of PCSs, and (2) those that are needed in exposure evaluation and hence In developing media- specific safe level advisories for PCSs. The latter properties will be briefly summarized herein. The widespread distribution of PCSs in the environment suggests that the major route by which PCSs are transported from treatment, storage, and dis posal facilities Is through the atmosphere In the form of volatilized vapor and adsorption on particulate smtter. Vapor pressure Is one of the Important properties affecting volatilization. The available vapor pressure data for conmerclal Aroclors, as reported In the literature, have been compiled and are presented In this chapter. Vapor pressure, as distinguished from partial pressure or true pressure, refers to the awxlmum vapor-phase pressure achiev able under equilibrium conditions at the soil-air Interface. Experimental data (U.S, EPA, 1980a) suggest that PCBs are strongly ad- :cr;*d on aarth materials, including soil. PCBs adsorbed on sdl, cr -.c in the soil mixture, will be subject to Ingestion If the contaminated sites are accessible to children or to adults with habitual pica. The bloaccuimjlatlon factor (In the food chain and In aquatic biota) Is also an Important physical parameter when there Is a likelihood of PCB transport In water. As pointed out previously, there are a number of congeners for each of the Aroclors. Thus, the properties listed herein for Aroclors represent averages over the various species that constitute the mixtures. The observation that environmental samples have contained more chioroblphenyls with high chlorine levels than is characteristic of freshly manufactured Aroclors is attributable 7-1 MQNS 224413 in large part to the possible metabolism and volatilization of lower chlorine species, coupled with enhanced sorption of species with more chlorine. The more connon types of Aroclors are shown In Table 4. Thirteen Aroclors were listed in a manufacturer's booklet (Monsanto Chemical Co., undated). These compounds range from oily liquids to white crystals and hard transparent resins, and generally have similar chemical and biological characteristics. The properties and parameters commonly needed In estimating the environ mental fate and transport of a given chemical are vapor pressure, solubility in water, soil-water partition coefficient, and bloaccumulatlon factor. These properties of PCBs, and other relevant properties, are shown In Table 4 (Surkhard et al., 1915; MacKey and lelnonen, 1975; Hutzlnger et al.. 1974; Monsanto Chemical Co., undated; Hwang, 1982; U,S. EPA, 1979a). Information on addition al physical and chemical properties such as viscosity, softening points, and other factors, can be found In references authored by Hutzlnger et a). (1974), Monsanto Chemical Co. (undated) end U.S. EPA (1980a). The vapor pressure of PCBs and their solubility In water are low, and tend to decrease as the number of chlorine substitutions on the phenyl rings increase. Aroclors are soluble In most aliphatic and aromatic solvents, and are highly resistant to the action of strong alkali or acids, or high tem peratures. Aroclors subjected to boeA tests are reported to have shown no evidence of oxidation (Hutzlnger et al., 1974). PCBs have been shown to adsorb relatively rapidly and strongly to various materials. Including soil, wood, plastic, and glass (Hutzlnger et al., 1974). Partition coefficients Indicating a measure of partitioning under equili brium conditions between PCBs at the Interfaces of air-soil, air-water, watersoil media are important parameters in exposure analysis. Experimental data are scarce. Data for the distribution between air and water In the form of 7-2 MOMS 224414 TABLi 4. CHEMICAL AND PHYSICAL P0PET1E$ OF PCBs Neteculer PCI weight Specific Orevlty Solutility* In weter (ag/L) *per press.(Mrtq) *t 2S*C Henry's lew coqsttnt (eta. ji /j ao)) PCI-1016 (Arochlor 1016) PCI-1221 PCI-1232 PCI.1242 PCI-1248 PCI* 1254 PCI-1260 PCI-1262 PCI-1261 PCI-1270 PCI-2565 PCI-4465 PCI-5442 PCI -5460 2.2`.5.5`. tatrachlombiphenyl 2,2.3.4,5.pantechlorobiphenyl 257.9 200.7 232.2 266.5 299.5 328.4 377.5 24,000 12,000 35.000 380,000 1.300.000 1,070,000 14,000,000 4 1.182 1.266 1.380 1 .*45 1.538 1.620 1.646 1.810 1.947 1.717 1.712 1.434 1.740 0.42 15.0 1.45 0.24 5.4*I0"` 1.2*IO"z -0.03 2.7*10-3 4*10" 6.7*10* 4.06*10-; 4.06*10*; 4.94*10*? 7.71*10"* 4.05*10-5 5.73*10 3.51*10 -4* -35 8.37*10 3 7.13*10 -3C 4.6*10*2 2.2*10*2 *Hutlinger et el.. 1874; Monsento Cheatcel Co., undeted. "MecKey end L*1nonefl, 1975. clb*eng, 1M2, end U.S. EPA, 1900c. Bloeccueuletton feeter; 31,200 L/kg. Soil-weter partition coefficient (U.S. EPA. 1900e); 22 - 1938 L/ky. MOMS 224415 Henry's Lin constant and water and soil, exist for some selected Aroclorj. Experimental data metsuring the distribution of PCBs between air and soil are nonexistent. Estimates of air-sol 1 partition coefficient can be calculated based on Henry's law constant and soil-water partition coefficient using one of several empirical relationships. The Henry's Law constant and soil-water par tition coefficient, in turn, are dependent on water solubility and percent organic carbon in soil, respectively. The Henry's Law constants shown In Table 4 are based on Information in MacKay and Lelnonen (1975) for PCB-1242, PC8-1248, and PCB-1260; and in a U.5. EPA research report (1980c) for PCB-1254. Burkhard et al. (1985) recently published a list of calculated Henry's Law constants for PCB-1242, PCB-124B, PCB-1254, and PCB-1250, The value for PC8-1254 Is an experimental value obtalned In the EPA laboratory In Cincinnati, Ohio, while others represent cal culated values. A comparison of Henry's Lew constants for PCB-1254 shows that the values In MacKay and Lelnonen (197S) and Burkhard et al. (198S) differ by a factor of 10, while those In MacKay and Lelnonen (1975) and the experimental EPA value (1980c) differ by a factor of 3. Since MacKay and Lelnonen's value is closer to the experimental value, Henry's Law constant; fsr ?CS'12^3, ?C21248, and PCB-1260 are tAken from MacKay and Lelnonen (1975). In the absence of experimental data, the soil-water partition coefficient Kd (cm3 water/g soil), and the air-soil partition coefficient, KlS (g soil/ air) can be estimated from water solubility and percent organic carbon (tOC) In soil, using-correlations presented by various researchers. For exam ple, the values for the octanol-water partition coefficient, K^,, can be used to estimate the values for the soil sorption coefficient based on soil organic carbon content, Kqq (cm3 water/g organic carbon), and the bioconcentration fac tor (BCF) by the following formula: I09 Koc 0.544 log Kgg + 1.377 log Kqc - 1.00 log Km - 0.21 log BCF - 0.76 log KM - 0.23 (Kenaga and Goring, 1980) Uarlckhoff, 1979) (Velth et al., 1980) (1) (2) <3) The K<j and K,s values then can be estimated by XOC Koc V H K _ a* *7 (4) (5) where K represents Henry's law constant. Since the comon unit for K is given in atm *>3/9 mol, a conversion factor of 41 {-1/2.44 x 10*2) should be multiplied In the right-hand side of Eq. (5) when the units for KM, H, and X<j are 9 soil/ cm3 air, atm w3/g mol, and cm3 water/g soil, respectively. The multiplica tion of KiS by the concentration of PCBs In soil will provide the concentration of PCBs In the air phase above contaminated soil of Interest under equilibrium conditions. It should be recalled that *he *ir.*oli 7rti*lnn coefficient. , has the unit of 9 soil/cm3 air. This Is equivalent to the ratio of the air-phase to soil-phase concentration, or (mg/cm3 a1r)/(mg/g soil). The esti mation of Kts requires the knowledge of Henry's law constant and the soil-water partition coefficient as given by Eq. (5). A listing of solubilities of each chlorinated biphenyl is shown in Table S (U.S. EPA, 1976c). There has been much speculation as to the possible role of photochemical reaction in the environmental decay of PCBs. The results of a study using mercury vapor (uv) sources (U.S. EPA, 1976c) have been difficult to extrapolate 7-3 MONS 224417 to environmental conditions because th radiation wavelength is not within the spactrum of solar radiation at the surface of the earth. Mora recant experi ments have been reported using a light source more closely approximating the spectral distribution of solar radiation, but the values for the photochemical reaction constants are not available. The Monsanto Chemical Company has reported vapor pressure data only for high-temperature conditions for Aroclors 1242, 1248, 1254, and 1260 (Monsanto Chemical Co., undated). The temperature used In presenting the data ranges from 150*C to 300*C. These vapor pressure values may be extrapolated to the temperatures which are of comnon environmental concern, but their accuracies would be doubtful. An EPA report presents kinetic data obtained from biodegradation experi ments using water-soluble Aroclor 1242 (U.S. EM, 1980a). The rate constants are presented for biphenyl compounds with up to the three chlorine substitutions present In Aroclor 1242. The data clearly show that meny of the chlorinated biphenyls with four chlorine substitutions do not biodegrade after 48 hours of degradation run. Inferring from the compositions of Aroclors 1242 and 1254 as conceivable that Aroclor 1242 may biodegrade to soma extent beeause It contains a substantial amount of chlorinated biphenyls with two and three chlorine substitutions. It appears that biodegradation of Aro clor 1254 would be insignificant or may not occur because most biphenyl com ponents have four or more substituted chlorine atoms. PCBs have several properties which make them toxic In the environment. In addition, they can significantly bloaccumulate and concentrate In the fatty tissues of all organisms. For example, the PCB concentration In resident fish is often many times higher than that in the surrounding water. PCSs are chem ically stable compounds that are able to persist in the environment for long 7-6 MOMS 224418 TABL 5. SOLUBILITY OF CHLOROBIPHENYtS IN MATE I? Compound Monochioroblphenyl $ 2 3 4- 01 chi oroblphonyIs 2.4 2,2' 2.4' 4,4'- Trlchloroblphenyls 2,4,4'2'.3,4- Tetrichl orobl phenyl s 2.2'.5,5'z.2',i,r2,2'.3,5' 2,2',4,4'2,3*,4,4 ' 2,3',4',5 3,3',4.4'- Pentichloroblphenyls 2,2',3,4,5 J *>< 4 C Z Hexachloroblphenyl 2,2',4,4'.5,5'- Octechloroblphenyl 2,2',3,3',4,4*,5,5'- Oecachloroblphenyl 4,4'-01chioroblphenyl Tween 80 0.\t Tween 80 11 * Humic icld extract Solubility mg/L (ppm) 5.9 3.5 1.19 1.40 1.50 1.88 0.08 0.085 0.078 0.046 0.034 0.170 0.068 0.058 0.041 0.175 0.022 0.031 0.0088 0.0070 0.015 5.9 >10.0 0.07 7-7 MOHS 224*19 periods. Impurities In conmarclal PCBs could amplify the PCB problem because of their similarity In chemical structure and toxicity (Monsanto Chemical Co., undated). 7-3 HONS 224420 B. ENVIRONMENTAL DISTRIBUTION The relent of PCBs Into the environment through disposal on or in lend, md through effluent discharges into waterways, together with their high atten uation characteristics and long half-life, has resulted In detectable levels in ambient air, soil, rivers, sediments, and In tissues of fish, wildlife, cattle, poultry, and a large portion of the human population. Measurable amounts of PCBs have been found in Antarctic ice, showing that atmospheric transport over long distances does occur (u.S. EPA, 1976b). Monitoring shows that the soils in the rural and urban areas where there is no record of PCS disposal or contamination, contain detectable amounts of PCBs (U.S. EPA, 1976c). One study estimates that 701 of the PCS load to Lake Michigan Is through atmospheric transport (University of Wisconsin, 1980). The results of soil sampling show that PCBs are more prevalent In urban soil than In agricultural soil. Oata Indicate that PCBs are rarely detected in agricultural soil, while urban soils showed PCB contaminations up to about 12 ug/g soil, with averages ranging from 0.01 to 0.21 ug/g (U.S. EPA. 1976c; Carey, undated). Sixty-three percent of tne soil samples showed detectaole PCB levels. The most prevalent PCBs In soil were Aroclor 1254, and, to a lesser extent, Aroclor 1260. The PCB concentrations In air samples over Lake Michigan taken during 1977 (University of Wisconsin, 1980) were lower than In those taken In the urban portion of Milwaukee. The main components were Identified as Aroclors 1242 and 1254, while the particulate-phase PCBs contained Aroclor 1260 In some Instances. The average concentration of PCBs in the air over Lake Michigan was 0.B7 ng/m3 (0.44 to 1.33 ng/m3). The concentrations of PCBs in the particulate samples were similar to those in the air samples. Air samples taken in later years MONS 224421 fro* Lake Michigan showed an avaragt conctntratlon of 1 ng/3, Thai* concen tration* are lower than those reported In the ambient air In the continental United States. The ambient air concentrations of PCBs for urban Chicago averaged 7.7 ng/ m3. The average composition in the air sampled was B61 Aroclor 1242, 131 1254, and 11 1240. The particulate-phase PCBs had a slightly different composition for the same Aroclor*. The ambient air in Milwaukee showed an average PCB concentration of 2.25 ng/a3. 3-2 MOMS 224422 9. ENVIRONMENTAL FATE AND TRANSPORT PC3s have been found in samples of air, water, soil, sediments, fish, birds, and mammals (Including humans) all ovtr tht world (U.S. EPA, 1930a). One* released Into tht tnvl ronfotnt, PCSs persist and collect In animal tis sues. Environmental problems caused by PCSs were largely unreported until 1966, when PCS contamination of fish, eagles, and humans was detected. The best-documented Incident concerning the effects of Ingested PCSs on humans is the case that occurred In Yusho, Japan, In 1968 (U.S. EPA, 1980a). Several other cases have also been reported (U.S. EPA, 1980a, U.S. EPA, 1976c). Sediments containing PCSs have boon reported In rivers, estuaries, and harbors (U.5. EPA, 19Slb), In concentrations ranging from 20 to 50,000 Mg/g. Leaching of PCSs could occur, although It will be constrained by the low solu bility limits. Once PCSs dissolved in water enter the soil medium. It Is possible that further migration will be severely retarded In view of the high soil-water partition coefficients. The retardation factors calculated from these coefficients can be used to simulate the arrival time and concentration increase in groundwater. This will be further explained later. Oesplte their low vapor pressures, PCSs can volatilize Into the atmo sphere. The migration of PCSs through air Is considered to be one of the basic mechanisms by which the ubiquitous presence of PCSs occurs in nature (U.S. EPA, 1980a). The how York State Department of Environmental Conservation (NYSOEC) analyzed sampler of PCS-contamlnated air at several localities. These analyses are shown in Table 6 (NYSOEC, 1979; U.S. EPA, 1981b). Concentrations of PCSs in the ambient air as high as 300 ug/m3 were reported at the disposal site. The average values ranged from 130 to 0.3 ug/*3. Concentrations of suspended particulates In the air In the vicinity of dump sites were also monitored by 9-1 HONS 224423 TABLE 6. PCB MONITORING IN AMBIENT AIR BY NYSDEC Sit* Max . PCB cone. (u9/^) Caputo dump Fort Millar dump Remnant area Moreau site Buoy 212 Ute Old Moreau Site (Sumer 1979) 300 35 10 15 Average PCB cone. (ug/*3) 130 24 9 5.6 0.7 (one sample) 0.3 9-Z NYSOEC, using high-volume air samplers {NYSOEC, 1979; U.S, EPA, 1981b). Th* geometric annuel mean concentration of particulate matter was 36 to 63 ug/m3, while the 34-hour averages were 71 to 144 ug/m3. The amount of PCBs adsorDeo to the collected suspended particulates was not reported. Based on mass-transfer models, MacXay and lelnonen (1975) calculated the half-lives of PCBs present In solution In a water column of 1 a depth. Half lives provide some indication of how fast a compound can volatilize from solution. The half-lives for Aroclor-1242, Aroclor-1248, Arodor-1254, and Aroclor-1260 are reported to be 12.1 hr, 9.5 hr, 10.3 hr, and 10.2 nr, respec tively. Half-lives will be longer when depths are greater than 1 m. The cal culated half-lives are for evaporation from a calm, liquid surface. Turbulence provides exchange of contaminants between the surface layer and the bulk of the water column. This exchange results In Increased emission rates, thus pro viding shorter half-lives. In addition to the Importance of attenuation mechanisms when PCBs inter act with soil, biodegradation Is also suggested as a potentially important machanlsm. Biodegradation studies using pure and mixed microbial cultures, th.s *ssult1ng metabolic changes In PC9 compounds, have been summarized by Hutzlnger at al. (1974) and Hwang (19B2). Photochemical degradation of PCBs in the atmosphere Is also of Interest, since a number of pesticide compounds have been shown to break down through the photochemical route. However, very little Information Is available in the literature to determine the extent of PCB degradation In the atmosphere. The safe disposal and treatment of PCBs discarded after their use in electrical applications Is a matter of great concern with regard to human health. Incineration techniques are frequently applied to PCB awterlal at elevated temperatures and high residence times. Several experiments involving ;-i MOMS 224425 pyrolysis of commercial PCBs have boon reported {Bu$*r and Rapp*, 1979). Th* PCBs used In th* pyrolysis experiments Included t*tr*ch1orob1ph*nyl, pentachiorobiphenyi, hexacnloroblphenyl, heptaehloroblphenyl, and octachlorobiphe nyl. Th* analysis of th* pyrolysis residues showed the presence of chlorinated furan compounds. However, the researchers concluded that the formation of furan compounds Is the result of uncontrolled burning of PCBs, and that th* emission of these compounds can be reduced by controlling the burning process. Th* high-temperature combustion of PCBs, such as In the case of transform er fires, results In th* formation of polychlorinated dlbenzofurans (PCOFs) and other toxic compounds. In an experiment studying conditions favoring the formation of polychlorinated dlbenzodloxlns (PCOOs), researchers found that the optimum conditions for the formation of PCOFs are a temperature of near 67$*C at a residence time of 0.8 seconds or longer, with 81 excess oygen (Midwest Research Institute [NRI], 1984). No conditions for th* formation of PCOOs are represented. The report states that detection of PCOOs was occasional and at low levels. 9-4 MOMS 224426 10. TOXICOLOGY The advisory levels for PC8 cleanup presented in this document (l.e., the permissible PCS soil contamination levels) are health-based values. These advisories are derived through calculations which first estimate human riskspecific (cancer end point) or acceptable Intake (Al) {noncancer end point) levels, and then determine the exposure rates which will effect these intake levels. Risk-specific doses are derived for the cancer end point, and a 10-day Al level Is derived for an approximate 10- to 30-day exposure considering only noncancer effects. A detailed assessment of the available cancer and noncancer health effects data for PCBs Is presented In Appendix 0. Only a brief overview and major Issues will be presented here. The determination of risk-specific Intake levels Is accomplished through a mathematical process which aukes use of a cancer potency factor and a reflected risk level or levels to estlaute the Intake level that would cor respond to such risk levels. Cancer potency factors for PCSs have been determined through an exhaustive analysis of animal studies. Values have been caicuiaceo uy Gnu vtrA, ,ioCu/ uu uw >*.34 (mg/kg^dAy)** ana by 073 (t?A, 13350) to be 3.57 (mg/kg.day)"1-. An average of these values, or 4.0 (mg/kg-day)*1 is used In the calculations presented In this document. A discussion of the data and methods used to estimate cancer potency factors for PCBs Is Included in Appendix 0. The determinations made by OftD and 0TS are both based on the same animal study-(Kimbrough et al., 1975), with only slightly different assumptions being Incorporated. A noncancer Al level was derived for PCBs during the preparation of this report, it must be emphasized that this Al Ignores the cancer end point and is based on toxicity other than cancer. The 10-day Al level of 100 ug/day 10-1 MOWS 224427 for a child and 700 ug/day for an adult, derived for use In this document, is based on feeding studies with rabbits and rats In which a NQAEL for de creased reproductive rate, and effects on thyroid and liver, were evaluated. These studies are described briefly below. Vllleneuve et al. (1971) found increased Incidences of fetal death, re sorptions, and abortions at 12.5 mg/k9/day of Aroclor 1254 in rabbits when exposed on days 1 through 28 of pregnancy, A dose of 1,0 mg/kg/day appeared to be without effect. Collins and Capen (1980a, b, c) In a series of studies on thyroid effects In rats, determined that 50 ug PCB per g of diet (- 2.5 to 5.0 mg/kg/day) for 4 weeks was associated with clearly defined adverse effects, but that doses of S ug PCB per g of diet (~ 0,25 to 0.5 mg/kg/day) were not. Carter (1963) demonstrated liver hepatomegaly In rats at doses of 20 ug Aroclor 1254 per g of diet (~ 2 mg/kg/day) for 14 days; such an ef fect, In the absence of other signs of toxicity (e.g,, fatty Infiltration of the liver), might not bo considered adverse. Grant and Phillips (1974) ob served increased liver weights In rats at doses as low as 5 mg/kg/day Aroclor 1254 given In com oil for 7 consecutive days. Collectively, these studies indicate tnat the experimental threshold for adverse effects of Aroclor 1254 ih studies of 30 days' duration or less Is at or near a dose of 1 mg/kg/day Thus, it seems reasonable to use this latter dose, a No Adverse Effect dose, as a basis for health advisories for Aroclor 1254 for short exposure durations. 10-2 MOMS 224428 11. EXISTING STANDARDS AND GUIDELINES Th 1968 incident In which toxic symptoms were experienced by Japanese people exposed to contaminated cooking oil gave rise to a great deal of concern in the United States with regard to hazardous chemicals. The U.S. Food and Drug Administration (FOA) started sampling foods for possible contamination by PCBs in 1969, and detected levels of PCBs in fish from the Great Lakes, in milk caused by use of materials containing PCBs, and In chlckans as a result of the existence of PCBs In the feed. The temporary tolerance levels for residues of PCBs proposed by FOA became effective June 29, 1979 (U.S. FDA, 1984). In the early 1970s, EPA proposed the establishment of criteria for PCBs being discharged In Industrial effluents, but has not so far Issued effluent limitations concerning PCBs. The Occupational Safety and Health Administration (OSHA) adopted standards for PCB exposure by Industrial workers. Subsequently, the National Institute for Occupational Safety and Health (NIOSH), after their extensive assessment, recommended lowering the allowable concentration of PCBs In the workplace, However. OSHA has not acted on this recommendation. Tii# Now 0wi l- ment of Health Issued an Interim guideline for the allowable ambient air con centration of PCBs to which Individuals may be exposed during the duration of a PCB reclamation project planned for the Hudson River (NTSOEC, 1979), The IPA promulgeted regulations relating to manufacture, processing, distribution In coamerce, use, dlposal, storage, and markings of PCBs and PCB items, The regulations originally became effective Hay 31. 1979, and were later amended, A complete presentation of the effective regulations can be found in the latest edition of 40 CFR Part 761 (U.S. EPA, 1984b). The PCBs referred to in these regulations Include any chemical substances or their 11-i MONS 224429 mixtures containing concentrations of chlorinated biphenyls of 50 ppm or greater. The regulations pertain to prohibitions on manufacturing, pro* cessing, distribution in commerce, and use. and specifically apply to PCB Incinerators, chemical waste landfills disposing of PCBs. transformers, pigments, electrical and heat transfer equipment, natural gas pipeline com* pressors, microscopy mounting medium, capacitors, PCS containers, and hydraulic systems (U.S, CPA, 1984b), The PCB standards and guidelines for numerical limitations of PCBs in food, drinking water, and ambient air existing at the present time are shown In Table 7. Because of the complicated nature of the CPA's regulations pro* aulgated under TSCA, these regulations are not presented In tabular form. U-E NOUS 22**30 TABLE 7. EXISTING PCS STANDARDS AND GUIDELINES Exposure pithMiys Food (FDA stindird)* Milk fit md dilry products Poultry Eggs Fish md ihtllflsh Flnlshtd inlmil fttd Drinking wittr (Now York Stitt) Anbltnt ilr Populittd irtis (Now York Stitt guldtllnt)* workplict (OSHA stmdird) Work sitt (NIOSH gu1dtlint)c U mo 4o Mixiauit illowiblt PCBs 1.5 wg/g (pp) 9/9 (pp) 0.3 9/9 (PP") 2.0 ug/g (PP) 1.0 U9/9 (ppm) 1.0 M9/L (wM 1.0 ug/n3 500 ug/n3 ug/it3l `U.S. FDA, 1984. "Ntw York Stitt Otpirtatnt of Httlth, 1981. 'N1U5H, 19/7. 11-3 12. EXPOSURE ASSESSMENT METHODOLOGY The presence of PC8s In environmental media poses t potentlel health risk to humans from the following sources of Intike: Ingesting contaminated soil Inhaling cortt mineted tlr Ingesting conttmlneted food drinking conttmlneted water e dermal absorption of PCBs In contact with skin Other exposure pathways affecting ecological communities, such as phytotoxicity to plants, may also need to be considered. If multiple-route exposures are possible, the concentrations allowable for a single-route exposure should be adjusted to meet the acceptable levels of acute and chronic health effect exposures from all sources of Intake. The amounts of each medium subject to human Intake used In this analysis are as follows: dally Intake of drinking water, 2 L/day; dally Inhalation of air, 20 m^/day (U.S. EPA, 1984b). Acute effects result from short-term or long-term Intakes, Carcinogenic effects are normally treated as resulting rrom lifetime intaxes, Safe leva is of PCBs In soil corresponding to 1-day and 10-day acceptable Intakes should be based on consideration for preventing acute health effects from short-term and longer-term exposures. Levels of PCBs In soil corresponding to acceptable Intakes for long-term effects can be derived from the acceptable dally Intake (ADI) based on long-term health studies for acute effects, or from the car cinogenic potency slope based on lifetime exposure for carcinogenic effects. The long-term risk level for ingestion of contaminated soil over a 70-year lifetime exposure can be obtained by 12-1 HONS 224432 69 yrs Risk - I 1611 (_5M)_-Co_ *_ (POT) (Ift) t=0 18*1 (lTJ (6) where Risk - lifetime risk; GI - gastrointestinal tract absorption of PCBs; SH - exposure frequency over t lifetime; Co a Initial concentration of PCBs In soil; k biodegradation constant (1/day); POT potency slope factor (mg/kg/ day)-1 for PCBs; IR dally ingestion rate of soil; SW body weight (70 kg for adults and 10 kg for children); and LT exposure time over a lifetime (70 years). If the contaminant undergoes biological or chemical degradation In soil, and follows first-order kinetics in its disappearance under isothermal conditions, the contaminant concentration will change as a function of time according to CQe*kt. The sumatlon in Eq. (6) Is necessary in order to add all the risks associated with the dally dosage over a lifetime. The Initial concentration of PCBs In the soil Is calculated at an assumed lifetime risk according to Eq. (6). A computer Is convenient to use to sum all the dally risks. The soil Ingestion scenario will be applicable to sites which are readily accessible, especially by children. Since the population Is living wti v>r ,;**r the s;ta, the exposure to PCS* due to inhalation of contaminated air cannot be neglected. In order to account for the Inhalation exposure In deter mining the allowable PCS levels In soil due to the combined routes of ingestion. Inhalation and dermal absorption, the ambient air concentrations at the expo sure points are needed. The concentration of PCBs In the vapor phase Is the result of the volatilization of the PCBs from the contaminated soil and their dilution by winds. The dilution factor for ambient air concentrations can be defined as D - C,/CM 12-2 (7) NONS 22*433 where Ct (yg/m3) the ambient air concentration at an exposure location, and C|s (ug/m3) - the concentration of PCBs In air at the soil surface where the emission occurs. The value of Cag continuously Increases as the PCB con* contrition in soil Increases* until the concentration of PCBs In the air phase corresponds to that of PCB vapor pressure. Beyond this point, a further In* crease In PCB concentration In soil will have a minimi effect on the vola* tllliatlon rate. Once exposure pathways are Identified, exposure evaluation requires infor* nation on the levels of concentration to which a given target population may be exposed. Each pathway my require route-specific evaluation. A general method for estimating exposures for contaminated sites will be described first. The method can bo simplified by eliminating those pathways that are unimportant or unrelated In the evaluation of PCB advisories. The relevant assumptions for the simplification are described below. 12.1 Estimation of Exposures for Contaminated Sites The combined human Intake of contaminants from all exposure pathways should not exceed the acceptable Intake (AI, In mg/day) needed for preventing adverse effects from short-term and lifetime exposures. The intaxe from an Individual route when soil Is contaminated can be expressed quantitatively as follwxs: 1} Intake by soil Ingestion (mg/day): I, (C.)(IP x io-3)(QI)(SM)(P) (8) The term (Cf)(IR) In Eq. (B) represents the dally amount of a contami nant Ingested resulting from soil Ingestion, In ug/day, because C, rep re 12-3 HONS 22**3+ sent* the contenrinmt concentration In toll Ug/g) or ppm (both units re equiv*lent), end IR Is the soil Ingestion rte (g/day) end QI Is defined In Eq. (6). The factor iO"3 Is needed to convert the unit from ug/day to mg/day. The fraction of the Ingested contaminants that will enter human organs and systems to cause toxicity Is given as GI. An Individual may not always be present on the contaminated site over his lifetime. The frequency factor of exposure over a lifetime, $M, represents the fraction of a lifetime that an individual will be exposed to the contaminants under consideration. The factor F Is necessary because soil Ingestion only occurs during childhood (1 to 5 years of age), and the weight of the human body changes from childhood to adulthood. 11) Intake by air Inhalation of volatilized contaminants (mg/day): I2 - (Ktl)(C-)(D)(IM x 1q3)(ABA)<SM) Z * (9) In Eq. (9), Kas, D, and IH represent the soil-air partition coefficient, given by Eq. (6), g io11/cm3; the extent nf nllutlnn m ;iven by Eq. (7); '.nd the average dally Inhalation rate of ambient air (m3/day), respectively. The term (K|t)(Ct)(D)(I0^) represents the ambient air concentration of a pollutant at the exposure location In ng/m3 when K|f and C# are given In g sol 1/cm3 and mg/kg, respectively. The determination of the ambient air concentration at an exposure loca tion, (Kas)(Ct)(D)(I03), or the dilution factor In the term, requires the esti mation of transient emission rate, and the use of dispersion modeling. The emission rate will not only be transient, but It will also be retarded by soil or equivalent cover material. This phase of the problem requires solution of a 12-a HONS 224435 partial differential equation, ai described in the Section 16. If the concentration of PCBs in soil Is at or above saturtion conditions, under which the air phase concentration of PCBs is equal to the vapor pressure concentration for a particular Aroclor or a mixture of Aroclors, the further increase In C, will not increase the ambient air concentration, assuming that other factors, such as temperature, remain constant. Therefore, the dally Intake by inhalation remains constant above the concentration of PCIs In toll providing saturated air concentration. This concentration of PCBs In soil, or the saturated concentration in soil for air Inhalation, will be denoted by csm* iii) Intake by dermal absorption (mg/day): I3 - (C#)(CR x 1Q-3)(A8S:($M) (10) There are many occasions when children playing In the yard or adults working in the garden will come In direct contact with contaminated soil. Dermal contact does not necessarily constitute adverse exposure. The contaminant needs to be systemic to be absorbed Into the human body and to exert toxicity. In Eq. (10), the term (Ct)(CR) represents the contaminant contact rate with skin In wg/day since C$ Is In ufl/g (-ppm) and CP Is the dermal contact rata of soil In g/day. The factor 10*3 Is used to con* vert the contact rate from ug/day to mg/day, and SM will be 1 when the short* or longer-term (10-day) exposure Is estimated, and will be between 0 and 1 when the lifetime exposure Is estimated. 12-5 NOUS 224436 1v) Intake by drinking water (mg/day): U " (C*)(I*)(SH) (ID In Eq. (11) It-Is assumed that the contaminant In drinking water Is completely absorbed Into the human body at the average dally water con sumption rate of IW or the absorption fraction Is 1. In order to relate the contaminant concentration In groundwater, C*, to the contaminant con centration in soil, CSl a fate and transport model can be used to estimate the concentration In the leachate entering groundwater, or Qw - C^/fg* g/L (12) where fg represents a functional relationship describing contaailnant trans port In groundwater. This function should be selected to suit the most appropriate conditions for the system. The leachate concentration, C^, referring to the contaminant concentration In liquids just before entering jrcundwater, should not be confused with the contaminant concentration in groundwater, which results from mixing of the leachate with groundwater. Also, care should be exercised In using groundwater transport models, be cause some models will treat the leachate concentration as a boundary con dition, while others require the contaminant concentration In groundwater as a boundary condition, which should be obtained by groundwater monitoring. When the units of C* and are all In mg/L, then the function fg becomes dimensionless, host leachate from hazardous waste land disposal sites may enter groundwater over a finite surface area, fevering area source models for simulating pollutant transport In groundwater. 12-6 HONS 224437 There Is no reliable method of predicting the leachate concentration from the contaminant concentration in soil, or vice versa. For the exposure evaluation, an equilibrium relationship vetween soil and leachate Mill pro vide a first approximation. Monitoring data can also be used relating the concentrations between leachate and soil. An equilibrium condition can be written as c, - (KL,)(CL), *g/kg (13) where K^, Is a partition coefficient In (mg/kg)/(mg/L). Eqs. (11), (12), and (13) are cornelned to get u cs (IM)(SM) ITgHKiTs) (IA) Mhen the equilibrium condition Is not appropriate. It can be modified to Include transport processes between the soil and leachate. v) Incase by fish ingestion (mg/aayj: At the average dally fish consumption rate of IF (kg/day), and under the assumption of complete absorption of the contaminant associated with the consumption of fish, the exposure can be estimated as 15 (CF)(IF)(SM) (15) where Cp Is the contaminant concentration In fish. The use of the biocon centration factor 8CF, (mg/kg f1sh)/(mg/L water), to relate pollutant con centrations In fish and water, gives 12-7 HONS 224438 Is (BCF)(Cw)(IF)(SM) (IS) where It 1i assumed that contaminants are present in water In dissolved form and that bottom sediments or benthal deposits on which pollutants may be ad sorbed are not directly swallowed by fish. Under the condition of equili brium between the pollutant-containing soil and leachate which Is generated from the soli, substitution of Eqs. (12) and (13) Into Eq. (14) results In (BCF)(IF)(SM) (17) The transport functions, fg. In Eqs. (14) and (17) may assume distinct mathematical descriptions, because one pertains to transport In groundwater and the other to that In surface water. vl) Intake by Inhalation of contaminants adsorbed on particulates (mg/day) may be expressed by I6 - (Cp)(lH)(C# x 10-9)(A8P)(SM) (18) Contaminant-containing soil can be airborne by blowing winds. In addition, toxic substances volatilized from contaminated soli can be ad sorbed on particulate matter present In the ambient air. Exposure to con taminants occurs because of Inhalation of air containing these particulates. The exposure location could bo distant from the source of emission, or In the vicinity of the emission source. Exposure concentrations will change accordingly. Another form of exposure relates to Inhalation of air con- 12-8 NONS 2244)9 talnlng particulate matter on which volatile conitltuentt are adsorbed. The Intake rate can be estimated based on the concentration of contami nants m wind-dlspersed soil or on particulate matter, C, ug/g (-ppm), and the concentration of the particulates In the ambient air, Cp ug/m3, as shown In Eq. (18). The absorption fraction, A8P, 's used because contaminants present In or on soil (or particulate matter) may be bound on the solid material, reducing the contaminant's absorption rate. Finally, the factor 10" Is a conversion factor to make the units consistent. vll) Intake by Ingestion of vegetables (mg/day): The intake rate due to Ingesting IV kg/day of vegetables, plants, or agricultural products containing cv mg/L of contaminants will be 17 " (CV)(IY)($N) (19) If it Is assumed that equilibrium Is established between the contaminant concentrations In plant and soil, then the exposure can be modified as: 17 ' Usv)(Cs)(lV)(SM) (20) where K#v Is a partition coefficient defined as contaminant concentration in plant/total contaminant concentration In soil (mg/kg pi ant)/(mg/kg soil). viil) Intake by Ingestion of food maat: The contaminant Intake at consumption rate of IN (kg/day) of meat con taining C,, (mg/kg) of pollutant Is 12-9 HONS 224440 Ib " (C)(IM)(S) (21) Here again, an equi librium relationship Is assumed between the contaminant concentrations In the animal body and plants. Therefore, the Intake rate due to meat consumption Is 13 ' Uvm)(Cv)(lM)(SM) - OWOCsvHCsHINHSM) (22) where Ky^ and Ktv are the partition coefficients used to describe pollu tant distribution between mast and vegetables, and the partition between vegetables and soil, respectively. 12.2 Determination of Permissible Pollutant levels in $011 The total Intake from all possible exposure pathways Is sat equal to the acceptable Intake (AI) for short-term and chronic health effects; or AI Ij I3 (23) Eq. (23) can be solved for permissible contaminant levels In soil correspond ing to each acceptable Intake. It is possible that some exposure pathways occur independently of others. For example, a residence which Is located on a contaminated site may use drinking water from a clean public water treat ment system, and may.thus be free of contaminants found on the site. It 1$ also possible that domestic animals are not raised for food consumption on the contaminated site under consideration. Under such circumstances, all exposure pathways need not be considered. If exposure pathways of significant concern are related to soli Ingestion, inhalation of contaminated air, or 12-10 HONS 224441 dentil contact with soil, as Is the cast for development of PCS advisories, Eqs. (8), (9), and (10) can be added to solve for cs, (Al)dOOO) cs -------------------------------------------------------------------------------- ----------- C(W)(GI)(F) (Kt,)(D)(IH){ABA x 106) (C*)(A8S)]SM (2*) The emission rate is limited by the air phase concentration in equili brium with the contaminant concentration In soil. Once the contaminant soil concentration reaches the level at which the vapor phase concentration In equilibrium with the soil is at the vapor pressure concentration, a further Increase In contaminant concentration In soil (Cs > Cw) does not Increase the emission rate. At or above this concentration, the ambient air concen tration remains constant regardless of the concentration of the contaminant in soil. Under such conditions, C In Eq. (9) Is no longer a variable, and therefore Eq. (24) does not apply. This situation can be remedied by considering the Intakes by the Individual route of exposure at a constant value of C* [C* in Eo. (91] for Inhalation exsosure. and solving for Cj. The form of the equation will be slightly different from that for Eq. (24). C . (AIKIOOO) - (KM)(CM)(D)(IH x 103)(A8A)(SM) * t(M)(6I)(F) (C*)(ASS)]$M (25) 12.3 Incorporation of Time-Varying Parameters The body weight of a human constantly changes until maturity. The cal culation of Als from the safe dose level (SL) given In mg/kg*day requires 12-11 MONS 224442 an assumption of body weight. for rigorous treatment, the ostliutlon of lifetime exposure should take into account changes In body weight, In this cast. It is convonlont to work with SL Instoad of AI for exposure calcula tions. For carcinogens with a potoncy value at POT (mg/kg*day)*l, tho equivalent SL at an assumed risk level, R (such as 10", etc.), can be obtained by (SL)eq. . R , mg/kg*day W (26) The risk level shown represents an upper-bound estimate. An upper-bouno estimate of risk of 10", for example, means that upon lifetime exposure to a contaminant, a person experiences an Increased maximum risk of devel oping cancer In a probability of 1 In one million. Snyder (1975) presented data on the change of body weight as a func tion of age. A regression analysis on Snyder's data for average male weight provides the following relationship. BU 3.16 3.52 (ago), kg for age 0 - 18 yr BW 70, kg for age greater than 18 yr (27) (28) To obtain the dally exposure averaged over an Individual's lifetime, intake rates given by Eqs. (8) - (10). (10), (17). (18), (20), and (24) should be divided by the body weight, and the dally Intake per unit body weight should be averaged by summing the total Intake per unit body weight over the period during which exposure occurs and dividing the result by LT. For purposes of Illustration, Eqs. (8) and (9) are repeatod below: 12-12 HONS 220043 1) The average dally exposure by soil ingestion per unit body weight in mg/kg*day can be determined as lx . 2"50 <Wy* (C0'kt)(IR x 103)(GI)(SM) Bw ' 1 day (BW)(IT) (29) Again. In Eq. (29) [also in in Eq. (30)], the contaminant present In soil is assumed to disappear by biodegradation and other reactions, accord ing to first-order kinetict. Other proceises affecting the concentration in soil are considered in the exposure analyses for Individual pathways. 11) The average daily exposure by Inhalation of volatilized contami nants in mg/kgday is calculated from I2 . 2I5M dIy* 0<M)(Coe_kt){0)(IH x loWxSH) W ' 1 day (BW)(LT) Similar expressions can be written for other exposure pathways. For conser vative contaminants, the term Cge"*1* In Cqs. (29) and (30) can be replaced by Cj. The total dose from all exposures should not exceed SL, or (SL)^. SSLL i*f1f + wIz * w for noncarc1no9n1c effects (30) (SL) q. WWW for carcinogenic effects (32) 12-13 NOUS 22*4+4 As before, Eq. (31) or (32) can be solved for the permissible concentration in soil, Cs. From Eqs. (B) and (29), one can solve for tha factor F for us* in Eq. (B). The uso of LT - 25550 days, and the assumption that soil ingestion occurs during ages l through 5 (t 365 to 1B25 days), yield F 0,323. The factor F does not depend on the soil Ingestion rate. Eqs. (8) and (29) use Eqs. (2B) and (27), respectively, for 8W. 12.4 PCB Advisory Evaluations Under normal conditions, significant soil Ingestion Is limited to children (Lepow, 1975). Although very limited information Is available on the ranges of age subject to soil Ingestion, one Investigation presented a case study of an adult with a history of habitual eating of garden soli, which may have been associated with a pica Illness (Wedeen et al., 1978). The fraction of soil contaminant absorbed by humans Is dependent upon the type of compound and Its soil contaminant adsorption characteristics, and Is generally smaller than that which can be expected when contaminants are present in food or drinking watder. PCBs can be removed from surface water, leaving It suitable for drinking, well water tnat comes rrom grouno water cog la oe a direct source uf drlnxtng water. The location of the drinking water exposure does not necessarily have to be at the site of the contamination, it Is assumed that the population which may be subject to PCS contamination In drinking water Is remote from the PCB-contamlnated sites, and the allowable water concentration Is separately calculated on the7>as1s of not eating contaminated soil and not Inhaling con taminated air In the Immediate vicinity of the site. The water concentra tion for a single-route exposure can be calculated as 12-14 MOMS 224445 AI 2 L/day (33) where Cw concentration of PCBi in water In mg/l, and AI the acceptable intake for prevention of acute and carcinogenic advene health effects. In mg/day. If fish caught In PCB-contanlnated surface water are eaten, and if the same water is the source of drinking water, the allowable concentration of PCBs (C* mg/day) should be determined as AI (34) where F is the daily fish consumption, BCF Is the bioconcentration factor (31,200 L/kg) (U.S* EPA, 1980b; U.S. EPA, undated). The national average of fish consumption Is 0.006S kg/day (U.S. EPA, 1984b). However, It Is more appropriate to use regional values where such data are available. The variabilities of Input values needed In Eq. (24) (appropriate for PCB exposure pathways) are wide-ranging for some values, and narrow for others. Tl.e ..viali:;-,' ,-;ta of olr used for calculation Is 20 3/day for both adults and children (U.S. EPA, 198Sd). Soli Ingestion rates used for evaluating short-term exposures are 3 and 0.8 g/day, representing conditions with and without pica, respectively (further explained In Section IS). One lifetime exposure evaluation 1$ based on an average dally rate of 0.8 g/day multiplied by factors to correct for the changing weight of the body as a person grows from a child to an adult. This exposure Is assumed to occur from age 1 to 5 years. However, the soli Ingestion rate of 3 g/day Is also used In long-term exposure evaluation. The absorption factors for PCBs through the gastrointes tinal tract for ingested soil, through the pulmonary organs for inhaled air. 12-15 HOMS 224446 end through the skin for contacted toil art assumed to be 0.3. 0.5, ano 0.0S, respectively (U.S. EPA', 1984a; ll.S. EPA, 198Se). The off-site factor Is assumed to be 1 for longer-term (10-day) exposure evaluations, and 0.5 for lifetime exposure evaluations, using the carcinogenic potency factor, A similar approach can be used for short-term (1-day) and lifetime noncancer exposure evaluations. However, these evaluations are not performed because of a lack of data regarding health effects. If all Intake routes, including drinking water, soil Ingestion, air inha lation, dermal contact, and Intake of PCBs by means of fish or other food are of relevant Importance, the allowable concentration levels can also be com bined In similar fashion. Since the scope of the present study pertains to site cleanup, the applicable formulas for combining concentrations are not presented, but they should be considered as the situation warrants. 12-16 HONS 22444? 13. WATER QUALITY LIMITS The concentration leveli of PCBs In drinking water are based on slngleroute exposures that are estimated to result In acute and chronic toxic effects. This does not Imply that bloaccumulatlon In aquatic organisms dees not occur. The assumption pertains to absence of fish contaminated with PCBs In the diet. If other routes are of concern, the allowable concentrations In meter should oe redefined. The following levels of PCBs In drinking water, corresponding to 10-day AIs, can be calculated for children and adults: e 10-day health advisory: Safi i nQ/ko*day*10 ko concentration L/day--* 0.1 ( 100 ppb) (child) 1 mo/ko*dav*70 ko concentration -----ltJO-2 L/day-- 0-35 .. ( 350 ppb) (adult) Similarly, tne concentration ieveis at tne various upper-oouno cancer risks assumed are calculated, and the results can be tabulated as follows: Upper-bound cancer risk Advisory level (ng/L) 10-4 10-5 10-6 10-7 875 87.5 8.75 0.8 Example chronic toxicity advisory level (at 10'* maximum risk) 10*6 risk 70 kjj. B.75x10'* mg/L (-B.75 ng/L) 4(mg/kg*day)'i*2 L/day 13-1 MOHS 224448 As Indicated previously, an Aroclor constitutes a mixture of many con* geners. Since each congener compound exhibits different solubility charac teristics, the applicability of these limits to Individual congeners is ion question. In the absence of short-term data for non-carclnogenlc effects, the 10-day health advisory may be used as the 1-day health advisory for commercial A rod ors. 13-2 HONS 224449 14. LEACHATE CONTAMINATION OF GROUNDWATER Contaminated leachate will Impact groundwater quality. To date, ground water monitoring data showing major contamination of groundwater by PCBs has been rarely reported. If the contaminated site Is located above an unsatur ated tone, soil through which leachate has to art grate to reach groundwater will adsorb PCBs and will greatly retard PCS migration, as evidenced by the high soil-water partition coefficients. Experimental work {U.S. EPA, 1980a) has shown that the adsorption characteristics vary depending upon the type of soil used. The experimental values are comparable to the partition coeffici ents estimated from the values of KM (water-octanol partition coefficient) given in Table 4. PCSs entering groundwater at hazardous waste sites could also be retarded as they are carried along the flow lines. The area-source groundwater model (Hwang, 1985) has been used to evalu ate the extent of retardation and dilution of contaminants In groundwater. A typical precipitation rate has been used to estlaute a leachate generation rate which Is a source term In the groundwater rate and transport model. Two Different values of the retardation factor covering the extreme variations of the soil-water partition coefficients were considered: Rd 127, corresponding to Kd 22 cm3/g; and S71S, corresponding to Kd 1000 cm3/g, where Kd represents the soil-water partition coefficient, and Rd Is the retardation factor o*d i h. <d. >b bulk density, e porosity). The results of e modeling show that when the concentration of PCBs In leachate Is maintained at 0.12 mg/L, the vertically averaged PCS concentration In groundwater at 1000 cm away from the center of a disposal site after two years of release is 0.5 X 10*4 mg/L and 1.9 x 10*7 ^j/l for th low and high values of the retar dation factor, respectively. Other parameter values used In this simulation 14-1 MONS 224450 were: leachate flow rate 23.4 cm3/s, groundwater seepage velocity 5 x 1Q_* cm/s, porosity of groundwater medium 0,35, depth of the aquifer 300 cm, size of disposal site 0.5 acre, and the bulk density of the medlun 2 g/cm3. The simulation was repeated for a distance of 1 km away from the site. The concentration values at that distance were very small. The groundwater transport analysis back-calculated allowable leachate con centrations entering groundwater below a hazardous waste facility, given the maximum allowable concentrations at a compliance point. These calculations do not account for "facilitated transport" via dissolved organics, cosolvents, etc. As Indicated previously, the maximum allowable concentrations were based on the allowable dally Intakes designed to prevent acute and chronic health effects, for th purposes of simulation, the maximum allowable drinking water concentrations at such distances as 1000 cm and 1 km from the contaminated site can be estimated. For acute toxicity, the drinking water concentration of 0.1 mg/l is assumed; for chronic carcinogenic toxicity, the concentration of PCB In groundwater assumed was 8.7 ng/l, corresponding to a 10** lifetime risk. The down-gradient groundwater concentration Is a complex function of leacnate concentration, olspars Ion end ratcrdctl sr. In groundwater, Initial dilution In groundwater, biodegradation (If any), and groundwater velocity. The functional relationship can be found elsewhere (Hwang, 1988), and takes the form 05) where represents the leachate concentration corresponding to the drinking water concentration C* at a point of Interest, and fg Is a functional relation ship which Incorporates fate and transport of PCB In the groundwater medium. 14-2 MOMS 224491 At the lower end of the retardation coefficient (Rj 127), trie calculated leachate concentrations under steady-state conditions are 570 mg/l and 4,3 x 10-3 mg/L, for acute and chronic levels, respeetlvely, for the concentrations maintained at the distance of 1000 cm from the site. The solubility values in Table 4 show that the 10-day acuta PCB levels fn leachate are above the solubility limits. The solubilities for most Aroclors are above the leachate concentration necessary to prevent the chronic effect of PCBs in groundwater. In other words, the chances ofexceeding the level of PCBs In groundwater which would causa acute toxicitywould be small, while leachate can enter groundwater to exceed chronic concentration levels, tt should be noted that the assumptions used In the calculations are that the points of exposure are 1000 cm and that the concentrations attainable under steady-state conditions are used. For different compliance points, the allow able leachate concentrations will change. In addition, steady-state conditions assume that the transport of PCBs In- groundwater occurred for a long time, so that concentrations at the exposure point are no longer changing. However, tne maximum allowable leachate concentrations for other conditions of transport, ano for oifferent locations or exposure, can aiso oe evaluates. For mot visua l congeners, the concentration levels should be reevaluated because of the dif ference In chemical and physical characteristics between an Individual congener and an Aroclor consisting of an array of congener mixtures. 14-3 MOMS 224452 IS. SOIL INGESTION PATHWAY A literature starch shows that there Is very limited Information on the rate of likely soil ingestion by children and adults which can b used In exposure assessment. The situation for which the Information Is derived dif fers from study to study. Lepow (1975) studied tha mouthing behavior of ten 2- to 6*year-old children In connection with Investigations Into tha principal cause of the excessive lead accumulation in the children. The total soil Ingestion rate for a 2-year-old child based on the average amount of street dirt, house dust, and soil Ingested by the child by putting Ms hands and fingers In his mouth, can be suaeaed as 0.6 g of soil per day. wedeen et al. (1978) observed the lead concentration in blood of a black woman with a 12-year history of habitual eating of garden soil. Using the levels of blood lead concentration and the concentrations of lead In the soil analyzed, they estimated the amount of lead the subject had consumed each year from her garden soil. From this estimate, the soil Ingestion rate Is estimated to have been In the range of between 1.96 and 3.9 9/day, with an average value at about 3 g/day. The lead concentration In the dried garden soil Is reported to be between 690 ug/g and 700 ug/g of soil. Investigators at the Centers for Disease Control present the lifetime ingestion rate of contaminated soil according to age group (Kimbrough et al., 1984). The paper states that the data presented are "based on work done study ing lead uptake from contaminated soils." However, the writers of this report were unable to locate the original experimental work or Its source to cite in this evaluation. The Ingestion rate Is assumed to change at different ages, and is given as 0 for the age group 0 to 9 months, as 1 g/day for the age group 9 to 18 months, as 10 g/day for the age group 1.5 to 3.S years, as 1 g/day for 15-1 MOMS 224453 tne age group 3.5 to 5 years, and as 0.1 g/day for a 5-year-old child. The second column of Table B shows the lifetime carcinogenic risk posed by Ingesting soil contaminated with PCBs at various concentrations. This table is prepared using Eg. (6) at the soil ingestion rate of 3 g/day for children aged 1 through 6 and an average weight of 10 kg. The values for other parameters used are $H 0.5, GI 0.3, and k 0. The risk values In the second column compare with those In the third column, which are prepared using the soil Ingestion rate applicable to different age groups, as suggested by the Centers for Olsease Control. TABLE 8. MAXIMUM LIFETIME RISK FOR INGESTING SOIL CONTAMINATION AT 0IFFERENT PCS LEVELS PC8 level In soil Ug/g) Lifetime risk Age-dependent (1R - 3) IR4 0.1 1 5 10 20 SO 1,54 x 10" 1.54 x 10'5 7.7 x 10-5 1.54 x lO"4 3.08 x 10*4 7.7 x lO'4 1.92 x 1Q-* 1.92 x lO"5 9.6 x 10*5 1.92 x 10*4 3.B x IQ'4 9.6 x 10*4 Taken from Kimbrough et Si., 1984. 15-2 HONS 224454 A computer program wit convenient to ute In carrying out th summation of dally Intakes ovtr Hfit1m# period. The lifetime risk represents an upper. Pound estimate of the unit risk that can occur as i result of Ingesting PC8contamlnated soil over a lifetime, and indicates the risk posed by a single exposure pathway; that Is, soil Ingestion is the sole route for PCS Intakes, and other pathways, Including air, water, fish are assumed to be Insignificant sources of human intake of PCBs. Since the population that will be subject to soil ingestion resides In the area and must breathe the air affected by PC8 emissions, the magnitude of PCB Intakes by the Ingestion and Inhalation routes needs to be compared to determine the significant pathway. The comparlslon 1$ presented In Section 18, Similarly, In order to determine the dally health advisory levels for a single exposure pathway, the dally PCB Intakes equivalent to Ingesting 3 g of soli In a day at various PCS concantrat Ions are calculated, The results are shown in Table 9. TABU g. MAXIMUM DAILY PCB INTAKE BY INGESTION OF SOIL AT VARIOUS PCB CONCENTRATIONS PCS level in soil (ug/g) 0.1 1 5 10 20 50 Dally PCS Intake at 301 absorption (mg/day) 0.00009 0.0009 0.0045 0.009 0.018 0.04S 15-3 HONS 224455 The exposure pathways for soil ingestion, air inhalation, and other routes must be evaluated. If one pathway is found to be dominant over the other, the insignificant pathway based on short-term and long-term Intake rates can be ignored. If they are comparable, the concentration levels need to be adjus ted to reflect the combined Intake rates by using Eq. (24) or co*lMt1ons of Eqs. (8) through (22). 15-4 NOUS 224456 16. inhalation pathway 16.1. INTAKE BY AIR EXPOSURE ROUTE Exposure to PCBs occurs at or near contaminated sites through inhalation of ambient air contaminated with PCS vapors or particulate matter on which PCBs are adsorbed. The PC8 vapors emitted from contaminated soil will be diluted by the action of winds before a person inhales the ambient air. When PCBs are adsorbed on soil, the vapor pressure of the PCBs above the soli sur face will be always less than the vapor pressure exerted by PCBs when they are present in pure form. In other words, the adsorption phenomena depress the vapor pressure that can exist under saturated conditions. This true vapor pressure Is referred to as "partial pressure.* When adsorption reaches Its saturation capacity on soil, the partial pressure will be equal to the pure PCS vapor pressure. Estimates of PCB concentrations In the ambient air Impacting the popula tion at hazardous waste sites are discussed In this section, as well as com parison with the intake rates of PCB through soil Ingestion. In calculating ambient air PCB concentrations, the first task was to estimate the emission rates of PCBs from the bulk of soil contaminated at various concentrations of PCBs. The emission rate calculations can be rigorously performed by the methods summarized by Hwang (19B2) for steady state conditions, and by methods presented In the Appendix for transient conditions. Based on the Inhalation rate of 20 Vday, and absorption rates of 501 and 301 for innaled and ingested PCBs (U.S. EPA, 1984b), respectively, the concen trations of PCBs In inhaled air and particulates equivalent to the dosage causing acute and chronic toxic effects can be estimated. The purpose of this exercise is to evaluate the concentrations of PCBs In the atr, which are compa- 16-1 MONS 2244*7 rab? to the ingestion dotage. Tablet 10 and 11 show thlt comparison for intake rates corresponding to acute and chronic effects respectively. Taole 10, for example, shows that a dally intake of 3 g of soil contain, mg l ug/g of PCBs is equivalent to a dally inhalation of air containing 0.45 ug/m3. The concentration of PCBs on particulate matter must be as high as 7,500 ug/g for the inhalation of particulates at an assumed concentration of 60 ug/m3 to be comparable to the ingestion of soil and Inhalation of air described above. This concentration Is used because the concentration should not exceed the primary ambient air quality of 7$ ug/a3 for particulate matter. Since the concentrations of PCBs on soil under consideration are In the range which is less than this concentration, it can be assumed that the PCB Intake by inhalation of particulate matter at contaminated sites Is relatively unlmportant. Similar arguments can be made for the results shown In Table 11 for long-term intakes. The equivalent air concentrations Cc shown in Tables 10 and 11 are calculated by the following formula; r (ua/m3) d,11< 1ntlU 11 l3 V*/m* * 20 nr/day 0.S (absorption factor) () 16.2. EMISSION EVALUATION SCENARIOS Emission rates are estimated for four different scenarios: Case l--as the PCBs volatilize from the Initial contaminated soil column, they are depleted from the column of soil by diffusions! transfer of PCBs across the toll-air interface, resulting in unsteadystate emission rates, and the layer depleted of PCBs acts as cover material retarding the volatilization rate; Case 2--the same scenario as in Case 1 except that the contaminated soil Is Initially covered with 25 cm of cover material; Case 3--PCBs are volatilized from the 16-2 HONS 224458 TABLE 10. COMPARISON OF PCS INTAKES BY INGESTION ANO INHALATION ROUTES FOR ACUTE EFFECTS PCB levels fn sot 1 (ppm) 0.1 1 5 10 20 SO Dally acute intake (mg/day) 0.00009 0.0009 0.0045 0.009 0.0018 0.04$ Egulv. air cone, for acute Ingestion (ug/m3) 0.009 0.09 0.45 0.9 l.B 4.S Cone, of PCBs on particulates (ug/9) 150 1,500 7,500 15,000 30,000 75,000 16-3 MOMS 224499 TABLE II. COMPARISON (IF PCS INTAKES T INGESTION AND INHALATION ROUTES FOR CARCINOGENIC EFFECTS PCD lc*lt In toll Uy/9) 0.1 1 S to 20 SO LIFotlao rltk t IR 1 I.S4 i 10-0 l,S4 > 10-0 7,7 x IQ"S 1.54 i 10-* 3.08 |0-4 1.1 * lo-4 Avorxgo dolly Intokt (9/do/) 3.86 i I0-* 3.86 IQ'* 1,93 x 10-4 3.86 x I0-4 M2 x 10-4 1,93 x IO*i Equl*. xlr com. Fop tho rltk (o9/oJ) 0.00019 0.0039 0.019 0.039 0.077 0.19 Cone, of PCBt on portlculotct (w9/9) 6.4 64.3 322 643.7 12B7 3217 MONS 224460 surface Of contaminated soil, and the PCB concentration at the surface is kept at a constant value; Case 4--the contaminated soil is covered with 25 cm of clean cover soil to retard the volatilization rate, and the concentration of PCBs at the surface is kept at a constant value. As pointed out previously, there exists a PCB saturation point above which the air-phase PCB concentration in equilibrium with (or partitioned with) the contaminated soil remains constant, and hence the emission rate of PCBs will also remain essentially steady over time. Below this point, a concentration profile of PCBs across the contaminated soil column starting from the surface to the depth of contamination will be created as volatilization progresses. This will result in unsteady-state emission rates which will vary over the period that exposure occurs. The period considered Includes 10 days for 10-day advisory, and estimated lifetime (70 years) for long-term advisory. The concentration of PCBs In soil corresponding to the saturation point can be estimated from the knowledge of vapor pressure and air-soil partition ing. For example, since the vapor pressure of Aroclor 1254 (7,71 x 10"5 mmHg) as reported in a publication, corresponds to the saturation concentration of 1,362.7 wg/m3, the PCB concentration in soil at the saturation point Is c . ________ 1.362.7 uq/m3 * [KtJ(g so11/cm3 air) x 10* cm^/m3] - 1,362.7 (2,Mx lO^Hl.OOO) , 4 (8.37 x 10*3 x 10) for an assumed value for of 1,000 cm3/g. The saturation concentration Is dependent upon the value of the air-soil partition coefficient. PCI saturation 16-5 MONS 224661 concentrations In sir, and tne corresponding concentrations in soil for the Aroclors considered as part of this evaluation, are tabulated in Table 12, based on the soil-water partition coefficient of 1,000 cm3/g for highly adsorbaole earth material (U.S. EPA, L9B0a), which is used in calculating the air-soil partition coefficient. A similar table can be prepared at the lower end value of the soil-water partition coefficient, which is approximately 40 cm^/g for sandy material (U.S. EPA, I98ua). Case 3 and perhaps Case 4 may be unrealistic, because as volatilization continues, the PCB concentration in soil decreases and the surface layer, depleted of PCBs, should act as an uncontaminated layer decreasing the emission rate. But this estimate should provide upper-bound values for omission rates. Cases 3 and 4 would be applicable in real-case situations when the concentra tion of PCBs in soil is high enough so that the air-phase concentration in equilibria with soil remains constant until the concentration of PCBs in soil decreases to the saturation point (Cyn, as defined on p, 12-5). Below the saturation point, the air-phase concentration will no longer remain constant, but will decrease in direct proportion to the soil-phase concentration, in the emission rate calculation, the partial pressure of PCBs as a result of parti tioning between the air and soil phases is used. Since the vapor pressures and Henry's Law constants art different for most PCBs, some typical PCBs are used for the purpose of illustrative calculations. Table 13 susmarizes the results of calculations fee amission rates for soil containing 1 ug of Aroclor-1254 and Aroclor-1242 per g of soil. The values shown for Cases 1 and 2 are the averages for one day omitted after the initial contamination at the concentra tion. This Is for illustration only because Aroclor-1248 and Aroclor-1260 are also used for omission rate calcualations. The models used for the omission rate estimation and necessary calculations are shown in Appendix A. The emis- 16-6 MOMS 224462 TABLE 12. CONCENTRATION OF PCBS IN SOIL AT SATURATION VAPOR PRESSURE BASED ON Kd 1000 cm3/g Aroclor-1254 Aroclor-1242 Aroclor-1260 Aroclor-1248 PCS concen tration in soil with saturated vapor {ug/g) 4 250 28.2 55.3 Saturated vapor concentration tug/*3) 1362.7 5823.3 822.8 7962.8 TABLE 13. PCB EMISSION RATES FROM 1 ug/g PCB SOIL AT DIFFERENT CONTROL LEVELS Scenario Emission rates (o/cm2*s) Aroclor-1254 Aroclor-1242 Case 1 Case 2 Case 3 Case 4 1.03 x 10"11 3.67 x 10*13 1.13 x 10*1 1.67 x lO*!3* 2.7 x 10*12 2.8 x 10*1* B.57 x 10"12 1.14 x 10*l4t Th models for estimating Missions from landfills underpredict the Mission rate m comparison to Case 2. The estimates for Cases 2 and 4 are based on tn mathematical model (described In Appendix A) and the empirical model (Farmer et ah, 1980), respect!vely. 16-7 HONS 224463 slon rates at various conctntratlon levels of PCB In soil are aide for evalua ting the imoact of volatilization on the exposed population at various loca tions. Table 13 snows that the emission rate,of Aroclor-1254 Is different from that of Aroclor-1242 at the same soil contamination level. The table also shows that the use of cover material is very effective In reducing the emission rate. The average emission rates over a period of 10 days, or a lifetime, for Cases 1 and 2 can be similarly estimated by the rigorous mathematical formulae provided in Appendix A. As PCBs volatilize, the partial pressure of PCBs at the soil-air Interface decreases, and the soil layer, depleted of PCBs, pro vides the barrier for mass transfer, causing the emission rates given for Cases 3 and 4 to approach values comparable to those for Cases 1 and 2, respectively. The Thibodeaux and Hwang model (1982), originally developed for land treatment facilities, provides emission rates similar to those shown for Case 1 and 2 in Table 13. PCBs volatilized Into the atmosphere from a contamination site-will im pact the population In the surrounding region. The concentrations of PCBs at the point of impact need to be determined In order to evaluate the signifi cance of the air emissions compared with the soil Ingestion and dermal path ways. Acute and chronic Impacts are based on the dally concentrations and the concentrations averaged over an annual period. Emission rates correspond ing to all four cases of maintenance levels are used to estimate the concen trations of PCBs ihthe ambient air at the site and at distances of 0.1 km and 1 km, 16,3. AIR 0ISPERS10N MODELING Dispersion modeling Is used to estimate the ambient air concentrations which may be possible for dally and annual exposures. Olsperslon modeling for estimating the annually averaged concentrations makes use of six stability 16-B MODS 224464 classes, six Mind speed classes, and 16 sectors, assigning the receptor point to one of the 16 sectors. The Mind rose data consisting of 6 * 6 * 16 576 elements ar compiled by the National Climatic Center In Asheville. North Carolina. The dispersion model for the annual concentration sums th con centration contributions over the entire range of stability classes and Mind speeds for each exposure location downwind of~the contamination site, and can take the following form (Bruce, 1969); s C(X,k) 2.03 x 106Q l 1 *1 li)l,X 6 t 3< (37) where C(X,k), the annual concentration located In a sector k at a distance of X downwind of the site (ug/m^);(a)1,X standard deviation of the plume in the indirection (vertical direction' at distance X for stability class 1, Q emission rate, g/s, Uj mean wind speed for wind speed class j, m/s and fljk * frequency of wind In stability class 1, wind speed class j, and direc tion in sector k. Both X and the standard deviation have the the units of meters. The values for the standard deviation can be found in an air pollution textbook {War* and Warner, 1981), or can be determined by a curve-fitting equation of the fora <i>i.x " (38) where a, b, and d are empirical constants varying according to stability t and distance x (Mark and Marner, 19B1; Martin, 1976). The values for these constants are given in Table 14 (Martin, 1976). 16-9 HONS 224465 TABLE 14. VALUES OF CONSTANTS FOR STANOARO DEVIATION EXPRESSION AS A FUNCTION OF OOMNW1NO DISTANCE ANO STABILITY CONDITION Stabllity A B c 0 E F a 440.8 106.6 61.0 33.2 22.8 14.36 X < 1 km b d 1.941 1.149 0.911 0.725 0.678 0.740 9.27 3.3 0 -1.7 -1.3 -0.36 a 459.7 108.2 61.0 44.5 55.4 62.6 X > 1 fcm b d 2.094 1.098 0.911 0.516 0.305 0.180 -9.6 2.0 0 13.0 -34.0 -48.6 The estimation of the on-site ambient air concentration does not require the use of air dispersion modeling presented above. The ambient air concentration Is controlled by th extent of dilution before dispersion occurs down wind of tne source. The dilution cen be estlmeted from the knowledge on the rate of PCB emissions and volumetric rate of wind being mixed with PCB vapors. The method for estimating the on-site ambient air concentrations Is described in detail In Appendix A. 16.4. AIR EXPOSURE EVALUATION Table IS summarizes the results of dilution estimation and dispersion modeling to obtain the concentration levels of PCBs In ambient air at various locations considered for emissions of PCB-12S4. This table Is a suiwtary of one set of calculations for the PCB concentration of 1 ug/g in soil for each scenario. The wind speed of 10 mpn is used for both one-day and annual concen tration averages. The Climatic Atlas of the United States provides information 16-10 MONS 224446 on mnuil average wind speed. A default value of 10 mph represents a typical annual wind speed in the United States. A site-specific evaluation will require detailed wind rose information based on local measurements. TABLE 15. AMBIENT PCB CONCENTRATIONS AT DIFFERENT LOCATIONS (PCS IN SOIL 1 ug/g. PCB-12S4) Case 1 Case 2 Case 3 Case 4 On-site 0.61 1.4x10-3 11 0.017 Concentrations (uq/m3) 0.1 km from site Oally Annual 0.026 5.9x10-5 0.48 7.1x10"* 0.0065 1.47x10-5 0.12 1.8x10** 1 km from site Oally Annual 0.0016 3.5x10"* 0.03 4.3x10*5 0.0004 8.9x10-7 7.3x10*3 1.1x10*5 The standard deviation Curve for 0 stability Is employed In estimating the ambient air concentratlone at the distances of 0.1 and 1 km from the site as shown In Table 15. since 0 stability Is by far the most frequently occurring stability class. Although 0 Is the most coevon stability, an exposure-weighted average stability should be used for site-specific evaluations. The frequency with which wind* blow toward a sector of Interest is assumed to be 1 for evalu ating the worst-case dally concentrations, while It should be based on the most common of the standard 16 wind directions for estimation of the average annual concentration levels. The concentrations In ambient air on-site and at dis tances of 0.1 km and 1 km from the site are given In the table. Calculations are performed for the ambient air concentrations of PCB-1242, PCB-1248, and 16-11 MONS 224467 PCS-1260. but thc$ ere not tabulated here. The values In the table should not be construed as representing fixed ambient air concentrations at the location and under the mode of exposure. The values are presented by way of 11 lustra* tlon to compare the contributions to ambient air occurring given the different assumed conditions. The concentration of PCBs In equilibrium with soil containing 1 vg/g PCB-1254* which corresponds to the partial pressure of PCBs partitioned above the soil. Is 340 ug/m3. This represents the maximum vapor concentration when PCB Is emitted from the soil surface. Based on this concentration and the estimated ambient air concentrations given In Table 15, one can calculate the dilution factors of the emissions for use In Ed. (9) or (24). For example, the air dilution factor for the on-site exposure corresponding to the Case 1 emission rate would be 0 0.611/340 0.0018 The values shown In Table 15 can also be used to determine the dally In taxes and lifetime rlsx levels corresponding to breathing each ambient air le vel. For example, the dally Intake from the exposure to the ambient air con centrations of PCB-1254 at 0.1 km from the site for the Case 1 emission rate can be based on a dally Inhalation rate of 20 m^/day of air and 50* absorption factor for Inhalation. Oally intake (mg/day) C(ug/m3) 20 m^/day (1/1000 mg/ug) - 0.026 (20)(1/1000)(0.5) 0.00026 mg/day 16-12 HONS 224468 Th stmt dally Intake can bt obtained by using Eq. (9): Dally intake (8.37x10*3/1000)(1/2.44x10*2)(1)(0.026/340)(20)(103)(0.5)(1) 0.00026 mg/day Similarly, the lifetime risk associated with breathing the ambient air can be calculated as follows: Risk * C(u9/i3) * 20 m3/day . 1/70 kg 1/1000 mg/u9 (4) (mg/kg/day)*1 (0.5)(0.5) where C If the ambient air concentrations shown In Table 16 and the value 4 (mg/kg*day)*1 represents the potency factor for Pels, and an additional factor of 0.S is the off-slte'factor under the assumption that a resident stays in the area SOI of the time. A series of calculations can be performed as shown above, or the procedure shown above can be reversed to back-calculate the PCS contaminations in soil which will provide the allowable ambient air concentrations at the locations considered and at the acute and chronic effect levels. 16-13 HONS 22*469 17. OERMAL CONTACT PATHWAY Deposition of contaminated soil, dirt, or dust on human skin can provide another pathway for human intake of PCBs. PCBs can be absorbed through skin when PCB-contamlnated particulates come Into contact with skin. Exposure evaluation requires an estimation of the amount of the particulates on skin, and the extent or rate of absorption. The absorption rate Is dependent upon the type of chemicals. Some chemicals are readily absorbed, while others are not. There are many factors affecting the amount of soil which can be accumula ted on skin. Factors include the exposed human skin area, contact time, type of soil, soil conditions, and type of activities. For example, the amount deposited on children playing In a contaminated area may be different from that on adults working In a garden. OHEA (U.S. EPA, 1984b) has made an estimation of the amount of soil depositlon on skin based on the studies by Lepow (197S) and Roels et al. (1980). Both investigators, using adhesive tape, measured the amount of soli and dirt accumulated by children on exposed areas such as hands, palm, and fingers. The measured amount of soil ranges from 0.5 to l.S mg/cm2, with an average value of 1 mg/cm2, it should be noted that this is an average value over the surface of the exposure area, and that some parts of the body may have more accumulation of soil than others. The area of human skin that will come In contact with soil or dirt depends upon the protective measures used during the time that such contact occurs, as well as the age group Involved. The exposed surface area of an adult is estimated to range from about 900 to 2,900 cm2. The exposed surface area of a child may be smaller In proportion to their total surface area. 17-1 MONS 224470 The ranges of values associated with the factors mentioned above makes It dif ficult to arrive at an average value for the amount of soil and dirt accumula ted on soil. An assumption of an average soil deposition at 1 mg/cm2, and exposed surface area of about 1,000 cm2 on a dally basis, provides an average dally deposition rate of 1 g per day. The variability Is such that this value may be different by a factor of as much as two. Investigators at the Centers for Disease Control present an estimated dally deposition of soil on skin according to age group (Kimbrough et al., 1984). Their tabular presentation shows that the dally amount of soil de posited on skin Is 0 for the age group 0 to 9 months; 1 g for the age group 9 to IB months; 10 g for the age group 1.5 to 3.S years; 1 g for the age group 3.5 to IS years; and 100 mg at age IS years. 17-2 HONS 224471 18. COMPARISON OF EXPOSURES BY SOIL INGESTION, INHALATION, ANO OERMAL CONTACT Table 16 shows comparisons of PCB Intake by various exposure routes. Calculations apply for PCB-1254 because the emission rtte Is dependent upon the sol 1-elr pertltlon coefficient, which Is different for each PCB. The ambient air concentration Is the on-site value based on the emission rate averaged over 1 day after soil is contaminated up to the surface without cover. TABLE 16. COMPARISON OF INTAKES BY VARIOUS EXPOSURE ROUTES* Exposure route Contact rate Absorption fraction Dally Intake (mp/day) Lifetime intake (mg/70 yrs) Soil ingestion 3 g/day (with pica) 0.3 0.6 g/day 0.3 Inhalation 20 m3/day*> 0.5 Dermal absorption 1 g/day 0.05 Oust Inhalation 20 m3/dayc 0.5 g x 10-* 1.6 x 10-4 6.1 x ID'3 5 x 10-5 6 x 10-7 ld 0.2 7B* 0.64f 7.7 x lO"3* `Used for Illustration: PCB-1254 at concentration of 1 ug/g In soil. b0n-s1te ambient air concentration based on 1-day average emission rate after surface contamination (no cover). Concentration of suspended particular matter: 60 ug/*3. d183 days/year for 6 years. Off-site factor 0.5. fAn average exposure of 1.5 mg/cm* and the exposure surface area of 1000 cm* assumed; off-sit* factor 0.5. IB--1 HONS 224472 Evaluation under the icentrlo of th* use of cover, or 1ongr-term amission averages, may change the dally intake by inhalation considerably. For example, a calculation shows that the use of 25>cm clean soil cover will reduce the dally Intake by Inhalation to 1,4 x 10*$ mg/day Instead of 6.1 x 10*3 mg/day. On the other hand, exposures by soil ingestion, dermal absorption, and dust In halation will be likely to decrease because clean toll Is used. The Ingested soil or the soil on the surface of the cover that may be accumulated on skin Is initially clean. Hence, th aally Intakes by pathways other than inhalation also become small. However, the concentration of PCBs In the initially clean cover material could increase as the PCBs In the air phase being emitted are adsorbed on the cover material as the liquid PCBs rise toward the surface due to capillary potential. The table suggests that soli Ingestion and inhalation are two competing exposure routes for PCS Intake. The dermal contact can also become a contributing route for some conditions of exposure duration. When a high concentration of particulate matter In the ambient air Is prevailing, the comparison shown in Table 1$ can no longtr apply. Consequently, the contrlbutlon to PCB intakes by Inhalation of particulate matter will Increase. There are a range of other possibilities which may result In a comparison different from that shown In Table 16. HONS 224673 IB-2 19. RESULTS 19.1. DERIVATION OF PERMISSIBLE SOIL CONTAMINATION Determination of the permissible PCB levels In soil for Intake through the combined exposure routes makes use of 1) q. (24) when the soli concen tration Is below the saturation point; and 2) the summation of Eqs. (B), (9). and (10), equated to the acceptable Intake otherwise. For each Aroclor under consideration, a separate exposure evaluation can be made for the following classes of exposure location and route; 1) Exposure occurs on-site. This can be further subdivided Into:, (a) sites which are readily accessible to children, and hence for which soil Ingestion Is a possibility, and (b) sites for which there Is no possibility of soil Ingestion, and hence exposure Is only through Inhalation; 2) sites which no population Is assumed to enter within the radius of 0.1 km from the site; and 3) sites which no population is assumed to enter within the radius of 1 km from the site. Two classes of soil Ingestion rates are evaluated when exposure occurs on* site (Class 1 above). For the first class, estimates of exposure are calcula ted for a person with pica who consumes 3 g per day between the ages of l-S years. For the second class, estimates of exposure are calculated for soil Ingestion of Q.f g per day between the ages of 1-5 years. For both classes, frequency Of exposure Is assumed to be every other day for lifetime exposures. For a 10-day exposure, soil consumption Is assumed to occur consecutively for 10 days. No soil Ingestion Is assumed for sites which are not accessible to population within 0.1 km or 1 km from the contaminated site. The route of exposure In these cases Is by Inhalation only. For lifetime inhalation expo sure estimates. It Is assumed that the population is exposed 501 of the time, l.e., 12 hours/day, or 6 months/year, 19-1 MONS 224474 The emission rate of volatilized PCBs can be considerably reduced by covering the contaminated soil by low-porosity uncontamlnated soil or clay material. The reduction In the emission rate will result In a decrease in ambient air concentrations of PCBs by the action of blowing winds. When PCB material is directly exposed to the atmosphere, the PCB levels In soil required to maintain the same level of exposure will be less than those expected when the PCB material Is covered with low-permeability material of appropriate thickness. The cover would also serve as a deterrent to soil Ingestion and direct dermal contact. The worst-case emissions would occur when the contaminated soil Is Initial ly exposed to the atmosphere and the soil Is contaminated up to the conditions exhibiting saturation vapor pressure. Models are used to estimate emission rates which can be constant or time-varying depending upon the degree of soil contamination. The constant emission rate can be assumed If the vapor phase concentration maintains Its constant value at the surface of contamination. There will be a profile along the layer of soil contamination for time-varying emission rates. The models for constant and time-varying emission rates are applied with or without cover material. Calculations corresponding to Cases 1, 2, and 3 for exposure possibilities are repeated at an assumed 2S-cm (10-inch) thickness of a soil cover Initially free of PCB contamination. The ambient air concentrations given In Table IS, and the resulting air dilution factors calculated, are based on an annual average wind speed of 10 mph. When wind speed Is lower than this. It Is possible that the dally dilu tion factors could be higher than the values In the calculations (less dilu tion). The combined soil concentration values based on Eq. (24) will be lower when the dilution factor Is higher. More accurate considerations of meteoro logical conditions will require site-specific evaluation, 19*2 HONS 224475 Among many factors affecting the amission rata (Including vapor prassura, soil-air partition coefficient, and Henry's law constant), the variability associated with the soil-air partition coefficient is more pronounced than any other chemical and physical properties. This is caused by the wide variation In experimental values for the soil-water partition coefficient reported In the literature (tl.S. EPA, 1980a), ranging from 22 to 2,000 ca3 water/g soil. For clay and sandy Materials, the range Includes about 40 to 1,000. The values of Kd higher than 1,000 are obtained from experiments using coal chars. For each Aroclor considered, the evaluation is performed for each set of conditions. The combination of these conditions can be summarized as follows: (1) No cover Is used. This Is designated as the case of "Uncovered Surface Contamination." Contaminated soil surface Is left uncovered after removal action in this case. (2) Soil cover of 25-cm thickness Initially free of PCS contamination is used. This is designated as the case of "25-ea-Thlck Clean Soil Cover". Contaminated soil surface Is covered with 25-cm-thlck soil cover. No soaking by liquid PCBs is assumed, which will reduce the effective cover thickness. (3) On-site exposure evaluation Is conducted at two different soil Ingestion rates: 0.6 and 3 g/day. The higher rate is reported for an Individual with the habit of eating soil (pica). For life expo sures. soil Is consumed every day for ages 1-6 years. For 10-day exposures, soil 4s consumed every day for ages 1-5 years. (4) Inhalation rate Is 20 *3/day for both an adult and a child. Popula tion Is exposed for 501 of the time for lifetime exposure durations. Ten-day evaluations are based on a dally inhalation rate of 20 m^/oay for 10 consecutive days. 19-3 HONS 224476 (5) honcancer and cancer effects are evaluated at the acceptable intakes corresponding to 10-day exposure on the first day of cleanup and after 10 days of elapsed time upon cleanup, and lifetime permissible exposures. (6) Two extreme values of the soil-air partition coefficients ire used in the evaluation. The high values of Kg (soil-water) correspond to low values of KtI (soil-air). (7) Area contaminated is 45 m x 45 m or approximately 0.5 acres. The combinations of these evaluation conditions are presented in tabular form in Table 17. The soil Ingestion rates of both 3 and 0.6 g/day are used In the evaluetlon pertaining to the longer-term (ilO-day) Intakes. The soil Ingestion rate of 0.6 g/day between ages 1 and 5 Is used for lifetime exposure evaluation, and this value Is averaged with respect to soil Ingestion and changing body weight over a lifetime. For each Aroclor, there are 120 different situations demanding different permissible levels of PCBs In soil depending upon the location, route and duration of exposure, elapsed time after site cleanup, and the type of health effects to be protected. Table 18 shows the corresponding values for Kg (soil-water partition coefficient) and Kat (soil-air partition coefficient) for Aroclors considered. The high values of Kg correspond to tho low values of KM, and vice versa. 19.2. SUMMARY OF RESULTS The method for determining the permissible PCB levels In soil Is programmed in a personal computer to avoid hand calculations. Tables 19 through 22 summa rize the results of computerized calculations for the case of "Uncovered Surface Contamination," and Tables 23 through 26 are for the case of "25-cm (10-lncn)Tnick Clean Soil Cover." The ranges are presented because the low and high values for the soil-air partition coefficient are used In the evaluation. 19-4 MOMS 224477 S-61 TAKE 17. EVALUATION CONDITIONS EON EACH ANOCLON loot Ion tod rout* of ocpoturo Intoko ritn Votoot for omUlon coofftclont (*0 BNl/t) m cow dtoth g > __________ On-tlto__________________ Sol I Inoottlon O t/A) (Mu lot Too derail Salt lomtlM (O.t /d) 1 Mulct 100 donut I Mulct loo Ml; O.t ko friM tin lohotctlee I to froo i Up InhcWtlon Ton-dt; totokO, child (100 1,9/d) Ton-do; Intoko. 0*1 It (700 ,9/4) 10*J rltk (0.0017S ,9/4) I0*` rltk (0.017S ,9/4) 10*4 rltk (0.17S ,9/4) I0*4 rltk (1.7S g/d) l4* l *d l KLg* kd c tl*4 t4 l* 1.000 0* 1,000 0 1,000 0 1.000 0 1,000 0 1.000 0 40 zs 40 21 40 ZS 40 ZS 40 zs 40 ZS 1,000 0 1000 0 1,000 0 1,000 0 1.000 0 1,000 0 40 zs 40 zs 40 zs 40 ZS 40 ZS 40 ZS 1.000 40 0 zs 1.000 40 0 zs 1.000 40 0 ZS 1.000 40 0 ZS I.000 40 1 ZS 1.000 40 0 ZS 1.000 0 1,000 0 1,000 0 1.000 0 1.000 0 1,000 0 40 zs 40 zs 40 zs 40 ZS 40 ZS 40 ZS 1.000 40 0 zs 1,000 40 0 zs 1,000 40 0 ZS 1,000 40 0 zs 1.000 40 0 zs 1.000 40 0 zs *Kd * toll-tutor port It loo coefficient to enttt of cm1 tttor/g Mil ( toot, to toll/conc. lo actor), hi 90 iSluoi cloto to (lt;i, 1m velvet dote to food. bHoaat 00 ttitr dot I puled ot "wrfKt <00tool ootloo.' <Hetat ZS cm (10*) clooo toll cover t#p> >* iModlototj of tor iwedlel tctloo. NONS 224476 TABLE 18. LOW ANO HIGH VALUES OF AIR-SOIL PARTITION COEFFICIENT USEO IN THE EVALUATION PCB type Kd (cm3 water/g tol1)* Hlgn Low Kat (o toll/or* a1r)b Low ------High 1242 1.000 40 2.35 * 10-5 5.87 x 10-4 m o r-* M 16 n 1248 1.000 40 1.44 * 10-4 1254 1.000 40 3.43 x 10-4 8.58 i lO-3 1260 1.000 40 2.92 x 10-4 7.31 x 10-3 ic* 1* the toll-water partition coefficient MO hat the unit of water/g toll which It equivalent to concentration In toll/concentration In watte. bKlt It the toll-air partition coefficient and hat the unit of g toll/car air. which It equivalent to concentration In air/concent rati on in toll. Thlt It calculated by (H/Kd) (1/2.44 * 10*Z). 19-6 NONS 224479 tutt IV. rt(Muaicsusatiktuio auactto-irMa icosoaniaaciowouiiMoaiM) tioa unis tatiuaa tat rwu it am Ii^wa ncMcar'tlvri.lin1 Ktmrtli mutt atrtoa* >fitilklt Itttlt lat/o) ttcrtttttotto it Cmw rm tttciMc ami 1--<os iso far tana fot !w a*ilt o.oeirs (10'' rial) t.om o.trs i.n (tH rlak) (If* rial) (It'* rial) 0* Ikt cMltataalt* l*li Sat! latMtlta*, Inkalatlaa* M-tf - tall tafactlaa*. Inkalatlaa* till/ lakatatlta aalp* 110-all 110**90 1100-7000 fl t.(Ot-t.tl t.tl-O.OO 0.04-t.f t.M-t.l t.l-t.k t.l-I.t 0.0-1.0 0-U 1.11,0 *.t-lt 110-zoo t.l la fraa caaiaalaaiat alta la*a 1at at talp* 1 ta frta HMMlaaM tilt - latillllaa aalf* at at* *% u O.t-It Itt-** llt-Mt l.lalt* l.lalO* n II n *lhsrl tifi tft-jjy tatttOa HttaO ta ataraft wl^Ht #0 n M II t| far a cklla tap aa aOtll, tMftclIvtljr. fCktlOrta apt! l.s, Him pica UaaKlat 1 | tall/Oar I. *Ckllarta apt! l-S, llktal pica (cttmatat O.t t ttH/Otpl. *liOwtptlta rtln art aiMri It V* It a>/0tp for Ikt tatfl-laTM M laaftr-ltra atac attar captftrot; II atkar (atra (traalil tiptiartl aaiaaat It H It *1/0tp *1 a rtttll 11 Itt tapt tapaiari ptr pear. 'laafat rtttll i* tack catt kacaatt l> fr VCtt (11*1, IIH, IIM, IMt) art caatltaraO, tack *Hk a aifltrttt apar prttwrt. M I) klfk at0 itt talttt ttr itll-tlr partltlaa cttfflcloot art tut la it# calcttatiaat, tit ttatttt tkttrttUtl attar-Vaaaa Halt, Practical rattati ratalra at frtt-flatlap Kl llpalOt ftr Ikt llall. MOMS 224480 IML( 10. rt*HISSM( Kt-IMO toil COOIMIMIIM U*ILS (tMCOfttfi SUOfkCl COOtWflMttON) w< rgnul*^xatnluan IkKlKir ihfl-l*ri until U luttlt if/flr* IlflHlUt I Id It td/ol COrrtloonOInf to t Mtlr fill IHtlllC 0t*t |h/<I too iir tun nw nr i*i't o.oom no-' mil o.oi/t t.nt i.u no-* rttii no-t mu no-* rim On tlx CMlMtnotlO III* - Jill Infill tM*. IdulillM* ll-00r - Sill IlftltlM*, Inhi III In* -JJ0 - Id'll It Id Ml|* fl-|l II-M0 00-?*00 ft 0.01 o.ot-o.o* 0.01*0.00 0.1 M4.1 O.I-O.O 1-0 I.O-t.O 1.0-0.0 0-10 ll-(l 01-110 0.1 la fria CMtoalMllO 11 to . imiiuIm Mlf* 1 la frM cnlwlMM 111* immiitw Mir1 It ft ft ft I.0-0.0 2H.1H W-ltO O.I|0* l.f>*-Mil|* 0,M0*-. ft Hfft-nn 1 10*4*1 IMHO. Mote# M inrift atlfOtl of 10 MO /0 If fir cMIO Ml m *0*11, rotooctfdtf. HMIOrwi ifM l-l. Itm plct IcMiMlif ] f ill I/Ilf). *CMIOrtn *frl l-t, illM fill (CnlMflf 0.0 f Mll/llf), I Bill t *11M ritn m illMtl to 0* 10 a>/or tM fMrt-tora ml toaftr-iora imtmtof oittltrot; ill it Mr (nri cftmU I noowrri mini li ot 10 r/*aj H rtMlt 11 III Mft momm for jioor. Urnfil ran It li iki uli Mon* I) fmr OCIi llltt, IMO, ItM, IMO> iri tMtfOorcO, ikI iltt llffiml door imuri, oM I) felfO mo In nlott for tul-tlr oortlttoa coo'flctoat oro inf lo tM ciicoiitlom. 0*1 Oomloi ni iMorottco* dOir-Mant Hall. IncUiil riitm roaolro Im-flMlof Kl IIm'Oi fir tM Mall. 19-8 MOMS 224481 iMil ft. nanisstiu pci-i4 sou coaiwtwiioa nuts umcontto sutrAcc cMiMiwnoa) LKitlM fNinikwi _______ NfllllUt Imti lat/al MfftumiM u_______________________________________ IkMMcir Ikart-lara* Kurtltu luu aaf44> ____________ into r<tt watlflt ton laa/44rl ' too far call# no far aOalt o.fiifi III** ml) o.tm i.m i.u II#*" rill) (I0-* flu) (to-4 rt(k) On Ihi (MlMlMIll (lit - Sail faotttlaat, taMialtaa* w-iaaf Sail tafaillaa*. taOalatlaa* na-aio taOalatlaa aalji* fl t.otf-o.oi O.tl-f.M o.oi-o.tt I.IM.I 0.1-0.4 0.1-0.4 I.O-f.O j.a-4.0 4.0-1.0 If 14-SI 440-410 l.l la fraa caataataataO tIlf taOalatlaa aalp* : la fraa caataalaataO Hta - taOalatlaa aalp* n n <1 tt s.o-r.t i.jfitJ 440-4*0 I.JalO1 a.fnaf *4 *4 I 'smu-uk t io-4af k *** HflH aa mrin Ml|Kl M II M I l| W i ckll M Milk, raaoactlfalf. Olllna un M, all* pica lcaaaal4 1 | tall/tap). *Cftl lira* H>* 1*1, Howl lie* IlMUMtaf 0.0 f ll/Wr). iwatailaa rtiH art mwl iikaS a*/Mr far ika Mri-im aw laafar-taw aaacaatar aiaafarat: all ataar taara ckraalt) aapaiafaa aiuaaf la ka It */# aa a raaall af lOf tart awataro par ftir. l|M)ti Ptaalt la tact caaa Oacaata I) faar Kll IU*f, IfM, 1144, 1140) art taaalOaraO, Mtk Hh a Olffaraat a#ar amun. aw I) hl0i aw Iw aataaa far tatl-alr part It Iaa caafriclaat art nif la *ka caltalatlaai. In aaaatai m Ihaaratlcal a#aar-0aaW Halt. IikiIiiI raataaa rawlra W fraa-flairtaf act llfplfi far taa llatt. 19*9 HOMS 224482 01*61 IMLt It. * Mill III l Kt-tftl Mil CMTMItellOa (MCDfttd SMTTKE CMIMUWItOk) lacattaa ate ravta af teaaa iifaun tecwar Mart-tarn* atcwlakla latte* aa/ter* Faraittlkla laaali lak/al (arraiaaatlaa la tMcar rial wtcttlc tew* laa/ter) lot far cklla no far ate It t.otm Ilf' rite) t.tm l.lfl i.?i 111*4 rite) Ilf* rltll (If4 rite) Oa ika caaiaalaaiat Ilia - Sail lafMtla**. lakallllaa* n-tff - Sail latMdate, lakalallaa* ll-Jt# - lakalallaa aalr* ft! MO-lit Hfi-nn ft t.t) t.tl-t.tt t.tl-t.lt t.l t.l-t.t t.l-t.t l.t 1.0-1.1 l.t-t.t H-IJ tt-tt M-tl t.l la traa taaiaaltelte ilia . lakalallaa aalr* 1 te (raa caalaataalM llta - lakalallaa aalr* ft ft n vt t-m nt-?at W-I.lalt4 r.fiit>- Vt I .tail* Vt ft `Sktrl'llfl i lt-4ay latte*. 4iM a arafiff aalfkti te It ate n l| far a ckllt ate aa atelt. rafted tel/- I(Mllri tfn 1-1, *lk |ui1t 1 | Ml (/ter). *Cfctltraa aft* 1-1, altkaat flu Utttateaf t.t I Mll/ter). 'Inluliilia ralai ara an--I ta ta It te/ter far ite itet-tm te laafar-tara mxuiff launfH; ll atkar Iter* urulc) uffiiru nwH te It r/te rwalt te lit ter* iiffmi ffr /iff. '(Hfn null la *Kk cm* taum I) <ter *Ct* (IMI, ttt, ItM, IMt) tea cwIteM, rack Uk (llllnm ufir frnun, *at t) Mf (at laa mIm* lar tali-alr rartitlaa caaffIdaat *r* M*a la ilia caltalMlaat. In teaatai aa (tearatlcal teter-teate Hall, /radical raataat raaatra te fraa-flktlaf Kl lltelte lar tte Halt. NOUS 2244*3 (AU 13. PlMIUItM PCI->343 $0>l CtoUHttof) UHtJ (3i-<a-lNlCK CUM Mil CMU) tKMlai M raatt af Dm ptun McMW llw1-ltri> <-**'** lw*l */> It* far eM 14 fto far Mad IPI>3 tM/ll torrtMtojlBl ___________Ctatat jilt tottlfll 4H1 tMM> Stilt (It*'rial 1*119 (.31 (If* rtrtl (If* rtrtl (It*4 rltll to (to ctowMim >U - toll laaailtaa* Itoalatlaa* Ift-Itt* - toll lapattlaa* Itoalatlan* *W-ttt - Itoalatlaa aalp* nl l3to-l4W Jltt-lftt VI t.t}-t.f f-t-l-t * Mf ll-to Ihn \ft-n M*vi VI l.l *a frto CaattotMt** - ItoctMlaa nip* I to frw iMMMU *<tt - Itotlltlto Mlf* n n vt n thn n VI VI n n it it `ttot-tm 4 iMt lata**. >IM t*ar*M toil *3 It aa* ft *t '*r * cklI* *to w atolt, rtoftttltolf. <Ckll*rw to** l-t. tt ** (catototkf > | totl/torl. *CM!*n* ** l-* alttort pica (caaaatoaf ** t Mll/tor|. ItolNiM rMn n HMto u to It '/tor far tto totn-Mto M Itopr-tan WKitokP tomnil til Mtor (ton ckTtotcl titowril MtMto t* to It '/tor to 4 rttoU tf Itt ton tto*ri p*r r**r. fpaaftt rtwlt la aack tmliikH II f*r PCt* (11*1, lilt. 13*4, IMP) an wattorto, aack altk aifftrato rapar prtitan, aa* 3| Mt W 1*a talam far toll-dr parlltlaa caafflctaat an *** la Ito calcalattaM. hi tonataa to IkaantUal appar-kaaa* Halt. Practical natoto rataln w frtt-Maalaf act llpMl far tto Matt. 19-11 HONS 224484 iMit i*. rtmttiMC rct-iito mil cMiMimmoi unit f-to-IHtCK CUM MIL CMtl) LkiIIm hI rant* *1 )w IHIWI .JS2!itljJi*SiUUlttLSSCSSi9S4!ja_!a--______ iwiiiMf rtwl-lin1 wwtMH >*>*** ___________twwr rlto toaclftttowt laMtor) i far cklU m far atoll o.win (IO-' rtu) .nn o.ift i.ji (M** rlM) (** rltt| IlH Hit) On tto uatMlWlM lit* tall tafattlM*. latolaltaa* 140*l*0f - tall lafttllM*. Inhalallaa* (M-n* - {ahtltllM Mir* at UOi-lMD IdO-n il 0.I1-.K a.to'O.i I.1-I.I I.I-I #.-l ! 10 1,0-14 10*440 tl-I.MO Mill4 1.1 to Iran CMtMlaatto HU - Iattaint Im Mir* 1 to frw (MMlMM HU - MUtid Mir* n V* n *1 r-i* l.talO* at at at ft at ft Huh M tnrtwMlHtl ( IMHt|liri toll* M4 M Mull. rtHKtlnl). OUMna Hn I-i. Mill |Ul Icaainartna ) f tall/Oarl* *C*iiotm tfat l-i, mum d (caataalaf 0.0 tall/tori. *IuIMIm ralat ara uuM l* to 11 M/tor fu tto ttort-Ura to lH|ir-Uf nuiw aiHMni; hi Mir (Mr* ctoMic) towiM hum i* to ) to/tor n null m IK tor* toiiiu rar r**r. 'Ihui rata It la HU c(M totMM I) (w Rll |IW, INI, IIW, IHO) M CMtltoraO, a*c* MU I (fTfaraat Mar araiiara. (to l| mi* ato laa *alaa* far ull-alr rarlltlaa taafffctaat ara **M la tto caltaUtlaat. hi (catat a# ttoacatiial Mt'Uato Halt, (radical raataa* mantra aa rraa*flatoaf (Cl ltaata* far tto lltot 21*61 HONS 2244*5 19-n imie fi. noBiiinit aci-ma.soii conTMiwmsi Uklj |-<.B-lHtC CUM MIC COftl) lac itlaa tap mil at Man riMHr* hWMtr akprt -l*ra* KtimUt Km t*!**i* 109 fr cm t4 roa far Mill Oa tka caalaalaatM till Sail laptailaa*. takalttlaa* im-im' Vail lafttllaa*. laaaUtlaa* W<nl lakalulaa aalp* 61 tn-IMO m-n *1 l.l ka Iran caalaalaata* tlla - lakalaUaa aalp* 1 ka fraa taadalaalM tit* laMUUaa aalp* n n ft n Itrail Iwrt) carratataHta t* _________cimf f*t t--tuit #im lt*/tl i.nm III*' Hat) i.nn (ir* rlk| B.m III** rl) (ll-^ rlttl i.ii-i.m' l.lf-#.M p.lf-l.gi II* H l.l-I.I l.f*l.t I.M.I n ft n MM i.i-a.i l*-ia r ** ft fft ft ft ft 'SMrl-tm i It-M latakt. Hum wrl|i MI0MI iMt X t| (M ClIK ant Milt, rilMIllltl). tckiiarta fn l-t. dik pH* lumMii ) i Mil/Pap). CM llrw **** l-i. d|M pit* IiMKIIm r*l*t tr* hum! M IipiiwN M M >/<*p | tar t*ll/4*r). tka lk*rt-Uf *M l*aftr-t*f* MMCMCpr (ap*a*r*a; It MKtr iaara tkrMlt) MmMn HMd t* ka I* 1/*p M rpMlt at Ilf 4*p npMur* p*r /aar. 'IM|H par prrtaMialalrtI,*tatKfl)ca*Mlp*ItaUatiMlaa II Mr talaaa Ktaritaltllfl*lal,lrIIpMar,tltItfaWa ,c|nINlfU| MlmCaPranIlIliMrMliantekka dtk I lllllrnt calcalatlaat. hi IimIti aa thaaratlcal *>if*aM Halt, Practical raataat rinirt a* fraa-ftpalaf act tlpall* tar |H Halt, HONS 224486 19-1* iMlt 71. KifllSIlIK PCI-1IM SOU CMTJMIMIIM IIWIS (ft-ta-IHICk CUM SOIL C0(| Lacallea aat raala af laa noaiara laacaacor ***rl-l#rn* iccaataOla laiak* a*/*T* IM far COM* m fr >4mII Paral**lkla l**l* (a*/ol carrnaaaalaa to *****Ctacor rlrt tooclflc taa/**l o.ooi n 110-' rnk) O.flfl f.US 1 -is O#-* rlitl (If* rlikl 110'" rlit) lit - Soil lafattlaa*, ia*latl*a* IIO-IM* - soil lafattlaa*. I**alttl*a* SM-OM * IlilllMIlll rtl 0.1 ka fraa caalaalaala* lit* . I*al*ll*a aalr* 1 ka fraa caalaalaat** ilia - laaalollaa aaljp* * 98 too-two mm sooo 98 98 98 0.01-0.01 a.u-o.a; 0.01-0.00 1-0 98 0.1-1,0 0.1-0-f 0.1*0,0 cm-no 98 1.0-1.0 11-MO 1.0-1.0 1.0-0 98 1M-M0 ito-ri* 98 98 98 H*Suhm*rt-lara***)-**miolakt*it*m. is o n if iw i *oii* m *o*it. mfm*if. cll*ra Ifn l-i, alto Olca |toli| ) I *atl/**r). *C*H4r t|t* 1-1. atthaat *** Uaaiaala# 0.1 f Mll/tar). ilMulitlM nln art tnnil li n If a*/*a? for ilw iml-Ura M laaftr-tara a*at*at*r Ufmini til NMf (Mr* ckraalc) oowro* nmH to *o 1* */0*r a rMlt * IK **r* lonw r*r r*#r. 'iwfii rata It ia cf um kacanta I) font lOl 11 M2, 11*0, 1114, INO) *r# ewilfirM, *Kl alt* I IIKviM ttoar ortttara. o l) hif* mo laa ralaa* far Mll-atr fcrtill*1 taafflelaat *r* ataO la t*a caicalatlaat. In Oaaata* aa Ihaarottcal aopar-Owa* Half, Practical roilOM ra*atr* aa fraa-llaataf ICO float** far t*a Hall. NONS 224487 .Yi'-: The symbol "vs" Indicates that no upper-bound limit for PCB concentr*tlons in soil can be derived from the exposure evaluation. This results mainly for to reasons. First, the emission rate cannot exceed the upper-bound value which can be expected when the air phase concentration of PCBs at the cone aminated soil surface Is maintained at the saturation point. The concentration at the saturation point corresponds to the vapor pressure concentration. Second, when the cover is applied, the emission rate Is not only retarded, but also the concentration of PCBs in soil being Ingested Is controlled by the amount of PCBs adsorbed on soil in equilibrium with the air phase being emitted. Hence, the concentration of PCBs In the Initially clean soil material cannot exceed the saturation point concentration. The PCB concentrations In soil corresponding to vapor saturation concentrations are 250, 55. 4, and 28 ug/g when Kd 1000; and 10, 2.2, 0.2. and 1.1 when Kd 40; for PCB-1242, PCB-1240, PCB-1254. and PCB1250, respectlvely. In actuality, the "no upper limit." or the level above vapor saturation, designated by vs, should be Interpreted with great care. The assumptions used In the exposure evaluation are critical. They include, but are not limited to: 1) no soaking of clean cover by liquid PCBs for the thickness of 25 cm; 2) no disturbance of cover meterlal by construction activities or children digging the ground; 3) no exposure to Initial spills when the values applica ble for 25-ca clean cover (Tables 23 through 26) are considered; 4) no popu lation enters the area within the respective radius of distances from the site; and 5) the cover material Is at least equivalent to soil material. The existence of free flowing PCBs liquids when placing clean soil cover material will have an effect of wetting the cover, resulting In the reduction of effec tive cover thickness. Hence, Assumption 1 will be tantamount to requiring the presence of no free liquids In the contaminated soil. 19-15 MOMS 224488 Sine* the ranges shc*n in these tables are dependent upon the values of the soil-air coefficient, the site-specific or contaminant-specific Informa tion will help find an appropriate level of PCBs for that particular condition. This can be done either by using the procedure outlined In the mein body of the report, or can be conveniently done by looking up the values listed In the Appendix for etch Aroclor at low and high values of toll-air partition coef ficient. The results In Tables 23 through 26 for each Aroclor esstm that the 25-cm clean cover material Is placed on top of contaminated soil. In this case, the Intake rate by exposure to soil Ingestion Is calcultted based on the estimated concentration profile existing In the cover materiel. This profile exists because of the establishment of the vapor-solid adsorption equilibria between the vapors being emitted and the soil. The concentration profile, which changes as a function of time. Is estimated by mathematical models, the concentration used for soil Ingestion Is the average concentration along the thickness of the initially clean cover material. If the prevailing contaminants at a site are PC6-1242, for example. Table 19 can be Interpreted as follows: (1) When the site Is amenable to access by children with possibilities of Ingesting the contaminated soil exposed to the atmosphere, the permissible PCS concentrations levels In soil should range from SS to 60 ug/g, and 92 to 247 ug/9 for prevention of noncancer effects from 10-day exposures at soil Ingestion rates of 3 g/dey and 0.6 g/day, respectively. When the site Is accessible to children and the population has the poten tial of on-site exposures to the contaminated soli and air over a lifetime, tne permissible PCB levels In soil should range from u.008 to 0.01, 0.06 to 0.1, 0.8 to 1.0, and 8 to 13 ug/g, corresponding to the best estimate of an upper- 19-16 MONS 22**89 bound oncogenic risk at 10*7, 10", 10"$ nd 10"4. respectlvely, Tht specific level wl11 be dependent upon the likely soil Ingestion rite end the extent of soil-iir partitioning. Because of the PCB concentration profile being esta* bllshed In the soil coluian as volatilization occurs, the PCS concentration averaged over the depth will gradually decrease over time. Hence, if the popu lation Is allowed to enter the site at some time after site cleanup, the per missible levels for preventing 10-day noncancer health effects can change. Again, the specific level will be dictated by site-specific characteristics such as the soil-air partition coefficient. (2) If there Is no possibility of population entering the contaminated site within a radius of 0.1 km from the site, the PCS levels In the soil can remain at the no theoretical upper*bound limit value (vs ig/g) without exceed* tng the 10*day AI upon Inhalation exposure for 10 days; and at 110*200 ug/g without exceeding the average dally dose corresponding to a IQ"6 risk for life time exposure. Similar Interpretations can be made for the results applicable to the carcinogenic risk listed at 10-4, 10*5, and 10-7. and to sites without affected population up to 1 km from the site. 19-17 MOMS 224490 20. LIMITATIONS OF APPLICATION It is assumed that the 25-cm (10-1 rich) clean cover material used remains undisturbed in the process of human activities on the site. At times this assumption may be found arbitrary, because an opportunity could eilst that would expose the contaminated soil surface In contact with the atmosphere by Inadvertent disturbances of soil surfaces, construction activities, utility Installation, precipitation, or children playing on the site, to name a few. In this case, additional thickness of cover material should be used, or the site should be made inaccessible to children or should be kept from any activ ities that would lead to disturbance of the soil surfaces. Spills on top of the clean cover will result In a situation equivalent to the surface contami nation case, requiring a more stringent concentration limit In soil. In this case, the results given for the 2S-cm-th1ck clean cover material do not apply. The tabulated results are Intended to be applicable under certain specific conditions. Under conditions similar to those used In preparing the tables, the values can be used without additional evaluations, A particular situation may warrant a site-specific evaluation which may require the use of conditions different from what has been assumed In preparing the tables. If the analysis Is available to show the specific type of Aroclor contaminating the soil, the Individual table should be used. If the value for the toll-air partition coef ficient can be better defined, the range of the permissible PCB concentration should be further narrowed. 20-1 MON5 224491 21. REFERENCES Binder, S. (1985) Estimating the amount of soil Ingested by young children through trace elements. Report by the Centers for Disease Control. Bruce, D.B. (1969) Workbook of atmospheric dispersion estimates, U.S. Depart* ment of Health, Education, and Welfare. Pub. No.: 999-AP-26, Burkhard. I.P.; Armstrong, D.E.; Andrtn, A.W. (1985) Henry's law constants for the polychlorinated biphenyls. Environ. Scl. Technol. 7:590-596, Buser, H.R.; Rappe, C. (1979) Formation of polychlorinated dlbenzofurans from the pyrolysis of Individual PCB isomers. Chemosphere 8:157. Carey, A. (undated) Chemical/element concentrations In surface soils of selected U.S. urban areas. U.S. Envlroomental Protection Agency, pri vate communication. Carter, J.w. (1983) Onset of hepatomegaly In PCB (Aroclor 1254)-treated rats, Bull. Environ. Contarn. Toxicol. 31(2):183-187. Collins, W.T.; Capen, C.C. (1980a) Biliary excretion of thyroxlne-I-125 and fine structural alterations In the thyroid glands of gunn-rats fed PCBs. kab. Invest. 43:158. Collins. w.T.; Capen. C.C. (1980b) Ultrastructural and functional altera tions of the rat thyroid gland produced by polychlorinated biphenyls compared with iodide excess and deficiency, and thyrotropin and thyrox ine administration, Virchows Arch. 8. 33(3):213-231. Collins, W.T.; Capen, C.C. (1980c) Fine structural lesions and hormonal alterations In thyroid glands of perinatal rats exposed In utero and fed by the milk to polychlorinated biphenyls. An. J. Pathol. 99(1);125-141. DuPont, R.R. (1985, Nov.) Evaluation of air amission release rate model pre dictions of hazardous organics from land treatment facilities. Presented at American Institute of Chemical Engineers meeting, Chicago, II. Fanner, W.J.; Yang, N.-S.; Letey, J., Dept, of Soil and Environmental Sciences, University of Cal 1fornla-RIvers Ida; Spenser, W.F., Science and Education Adnlnlstrati on. Federal Research, USDA. (1980) Land disposal of nexachlorobenzdne wastes: Controlling vapor movement In soil. EPA-600/2-80119. Prepared for U.S. Environmental Protection Agency, Municipal Environmental Research Laboratory, Cincinnati, OH. Grant, D.L.; Phillips, M.E.U. (1974) The effect of age and sex on the toxlclt of Aroclor 1254, a polychlorinated biphenyl. In the rat. Bull. Environ. Contam. Toxicol. 12:145-152. Huang, S.T. (1982) Toxic emissions from land disposal facilities. Environ. Prog. 1:46. 21-1 MOMS 224492 Hwang. S.T. (1985, May) Assessing exposure to ground water contaminants migrated from hazardous west* facilities. Proceedings, Conference on Management of unconfined Hazardous Waste Sites, Cincinnati. OH. hutzlnger. 0.; Safe, S.; ZltkO, V., eds. (1974) The chemistry of PCBs. CRC Cleveland. OH: CRC Press. Jury, W.A.; Spencer, W.F.: Farmer, W.J. (1983) Behavior assessment model for trace organics In soil. I. Model description. J. Environ. Quel. 4:558 564. Karlckhoff, S.w. (1979) Sorption of hydrophonlc pollutants on natural sedi ments. Water Res. 13:241-248. Kenaga, E.E.; Goring, C.A.I. (1980) Relationship between water solubility, soil sorption, octanol-water partitioning, and bioconcentration of chem icals in biota. In: Aquatic Toxicology. (Eaton, J.C.; Parnlsh, P.R.; Hendricks, A.C.: eds.). American Society for Testing and Materials, in press. ASTM STP 707. Kimbrough, R.O.; Falk, H,; Stehr, p. (1984) Health implications of 2,3,7,8tetrachloro-dlbenzodloxln (TCDO) contamination of residual soil. J. Toxicol, Environ. Health 14:47, Kimbrough, R.0,; Squire, R.A.; Linder, R.E.; Strandberg, J.O.; Mental 1, R.J.; Burse. V.W. (1975) Induction of liver tumors in Sherman strain female rats by polychlorinated biphenyl Aroclor 1260. J. Natl. Cancer Inst. 55:1453-1459. Lepow, M.l. (1975) Investigations in sources of lead in the environment of urban children. Environ. Res, 10:415. Lorenz, H,; Neumeier, G. (1963) Polychlorinated biphenyls: profile of a group of substances. WtV Medlzln verleg Munchen, MacKey, 0.: ttlnonen, P.L. (1975) Rate of evaporation of Insolubility contaminants from water bodies to atmospnere. Env. Scl. Technol. 9:1178. Martin, 0.0. (1676) The change of concentration standard deviation with istence. J. Air Poll. Control Assoc. 26:145. Monsanto Chemical Company. (Undated) The AR0CL0RS--physical properties and suggested applications. MRI. (1984, Oecember) Thermal degradation products from dielectric fluid. Prepared for u.S. Environmental Protection Agency, Office of Toxic Sub stances. EPA-560/5-84-009. National Institute for Occupational Safety and Health (NIOSH). (1977) Criteria for a recommended standard: occupational exposure to polychlori nated biphenyls (PCBs). OHEW (NIOSH) Pub. No. 77-225. U.S. Government Printing Office, Washington, D.C. 21-2 MOMS 224493 New York Stite Department of Environmental Conservation. (1979) New York State air Quality report, continuous and manual air monitoring system. OAR-80-1. Albany, NY. New York State Department of Health. (1981, March 16) Hemorandian from John Hawley. Nisbet, I.C.T.; Saroflm, A.F. (1972) Rates and routes of transport of PC8s in the environment. Environ. Health Perspect. 1:21. Roels. H.A.; Buchet, J.-P.; Lauwerys, R.R.; Bruaux, P; Clyaeys-Thoreau, F.; Lafontaine. A.; Verduyn, 6. (1980) Exposure to lead by the oral and the pulmonary routes of children living In the vicinity of a primary lead smelter. Environ. Res. 22:81-94, SCS Engineers, (undated) w-E-T model hazardous waste data bate. Final draft. Prepared for U.S. Environmental Protection Agency, Office of Solid Haste. Washington, O.C. Reiton, VA. Snyder, W.S. (1975) Report of the task group on reference manual. Inter national Commission of Radiological Protection No. 23. Fergamon Press, New York, NY. Thibodeaux, L.J.; Hwang, S.T. (1982) Landfarming of petroleue wastes: modeling the air mission problem. Environ. Prog. 1:42-46. University of W1sconsIn-Madlson, Water Resources Center and Water Chmalstry Program. (1980, March) Atmospheric chemistry of PCBs and PAhs. Prepared for u.S. Environmental Protection Agency, Chicago, 1L. U.S. Environmental Protection Agency. (Undated) Guideline for assessing hjnan exposure. Office of Solid Waste. U.S. Environmental Protection Agency. (1976a, January) Development of a study plan for definition of PCI usage, wastes, and potential substitution in the Investment casting industry. NTIS No.: PB251842 C.l. U.S. Environmental Protection Agency, Office of Toxic Substances. (1976b. February) PCBs in the United States: industrial use and environmental distribution; Task 1. Prepared by Versar, Inc. NTIS No.: PB252402. U.S. Environmental Protection Agency. (I976e, March) National Conference on Polychlorinated Biphenyls. NTIS No.: PB253248. U.S. Environmental Protection Agency. (1978, March) Microeconomic impacts of the proposed PCB ban regulations. NTIS No.: PB281881 C.l. U.S. Environmental Protection Agency. (1979a) water-related environmental fate of 129 priority pollutants, vol. 1. EPA-440/4-79-029a. u.S. Environmental Protection Agency. (1979b, May) Polychlorinated blpnenyl* 1929-1979: Final report. Office of Toxic Substances. NTIS No.: PB256559. MOMS 224494 21-3 U.S. Environmental Protection Agency. (1980a) Attenuation of water-soluble polychlorinated biphenyls by earth materials. EPA-600/2-80-027. U.S. Environmental Protection Agency. (1980b) Ambient water quality criteria document for PCBs. Environmental Criteria and Assessment Office, Cincin nati , OH. EPA-440/5-80-068. U.S. Environmental Protection Agency. (1980c, April) Determination of henry's Law constants of selected priority pollutants. Municipal Environmental Research Laboratory, Cincinnati. OH. (Authors: Warner, K.P.: Cohen, J.M.; Ireland, J.C.) U.S. Environmental Protection Agency. (1981a, April) Evaluation of PCB destruction efficiency In an industrial boiler. EPA-800/2-81-085a. U.S. Environmental Protection Agency. (1981b, May) Environmental Impact statement on the Hudson River PCB Reclamation Demonstration Project. Region II, New York, NY. U.S. Environmental Protection Agency, (1983) Analysis of adipose and blood sera samples for Individual PCB Isomers. Draft Pinal Report on EPA Contract 68-01-5915, 11/30/81 - 5/31/83. U.S. Environmental Protection Agency, (1984a, Nov.) Risk analysis of TC00contaminated soil, EPA-800/8-84-031. U.S. Environmental Protection Agency. (1984b) Code of federal Regulations, Title 40, Part 761. U.S. Environmental Protection Agency. (1985a) Drinking water criteria docu ment for polychlorinated biphenyls (PCBs). Environmental Criteria and Assessment Office, Cincinnati, OK. Pinal Draft. EPA-600/X-84-198-1, U.S. Environmental Protection Agency. (1988b, June 12) Personal communica tion, Don R. Clay, Director, Office of Toilc Substances. U.S. Environmental Protection Agency. (1985c, Nov. 7) Personal communication, Martin, P, Helper, 01 rector. Exposure Evaluation Division, Office of Toxic Substances* U.S. Environmental Protection Agency. (19SSd, Aug.) Development of statistical distributions.or ranges of standard factors used In exposure assessments. Prepared by 6CA Corporation for the Office of Health and Environmental Assessment. NT IS No: PB85-242667. U.S. Environmental Protection Agency. (1985e) Personal comeunlcation with Office of Toxic Substances. U.S. food and Drug Administration. (1984) Code of Federal Regulations, Title 21, Part 109.3D. 21-4 MONS 224495 Veith, G.O.; Hacek, K.J.; Pttroctlll, Carroll, J. (1980) An evaluation of using partition coefficients and water solubility to estlMte plocon- centration factors for organic chemicals in fish. J. Fish. Res. Board Can. (Prepubllcatlon copy). Versar, Inc. (1976) Assessment of wastewater management, treatment technology, and associated costs for abatement of PCS concentrations In Industrial effluents. Prepared for u.S. Environmental Protection Agency. Office of Toxic Substances. NTIS No.: PB251433 C.l. Versar, Inc. (1977) A first-order mass balance model for the sources, distri bution. and fate of PCBs in the environment. Prepared for the U.S. Environmental Protection Agency. Office of Toxic Substances, Washington, D.C. Vllleneuve, D.C.; Grant. B.L.; Khera, K.; Clegg, D.J.; Baer, H.; Phillips, w.E.J. (1971) The fetotoxlclty of a polychlorinated biphenyl mixture (Aroclor 1254) In the rabbit and In the rat. Environ. Physiol. 1:67-71. Hark, K.; Warner. C.F. (1981) Air pollution; Its origin and control. New York: harper and Bow. Wedeen. R.P.; Malllk. D.K.; Baluman, V.; Bogden. J.D. (197B) Geophaglc lead nephropathy; case report. Environ. Res. 17:409. 21-5 HONS 224496 OERI VAT I ON OF MOOELS FOR ESTIMATING VOLATILE EMISSIONS FROM CONTAMINATED SOIL COLUMNS UNDER TRANSIENT CONDITIONS Because of the limited aqueous solubility and high soil affinity of PCBs, It has been assumed that these compounds move vertically in soils* primarily by diffusion in the vapor phase. If transport of PC8$ Is by vapor phase dif fusion through interstitial spaces between soil particles, a mass balance over an infinitesimal vertical element of soil can be written as follows: AE(-Oe1iC, - AE(.0#1C) AAZJC )z Z.t 2+02,t it t (A-l) where: A cross-sectional area of Interest, cm2 C concentration of PCBs In the vapor phase In soil pores, g/cm3 Cs concentration of PCBs In soil, g/g 0. molecular dlffuslvlty, cmvs effective dlffuslvlty, emz/s ("01'E1'3) E pore porosity bulk density of soil true density of soil, Ps, multiplied by (1*E), g/cm3 t time, seconds 2 depth measured from the soil-air Interface, cm In Eq. (A-l), the effective dlffuslvlty, D#^, Is used In place of E^3'Dj to account for the tortuosity effect In porous media. The use of effective dlffuslvlty Is consistent with the findings which describe emission rates of volatile chemicals from landfills and soils (Hwang, 19B2; Thibodeaux, 1979; Farmer et a 1., 1980). The effective porosity for dry soil Is used for slmplicity. The effect of moisture can be Incorporated In the porosity term as shown by Farmer et al. (1980). Since changes in soil and vapor phase PCB concentrations occur slMly, it can be assumed that vapor phase concentrations and soil concentrations of PCBs A-l HONS 224497 are in local equilibrium. If PCB concentrations in soil and In Interstitial vapors approach equilibrium, they are related by the following equation: where Kg soil/water partition coefficient H Henry's constant (A-2) Rearranging Eq. (A-l) and substituting Eq. (A-2) Into the resulting rela tionship yields Del iijaz or *C . JC (A-3) (A-3) where De1*E TE41*Li-EJ-Kg7,Hy a cm iho dtflntd a* a e1 i K-S A-2 (A-4) (A-5) MONS 224498 where * ` * >s q. (A-3) can be solved to estimate PCB soil concentration, vapor phase concentration, and emission rate Into air above soil for the various cases described In this report if initial and boundary conditions are sped* fled for each of these cases. Case 1. Surface is exposed to the atmosphere. The boundary and initial conditions are 1. I.C. 2. B.C. 3. B.C. C - (H/K<i)C$o *t t * 0, i > 0 C (H/Kd)C$0. *-, t > 0 C 0, at 2 0, t > 0 where Cjg is the Initial concentration of PCBs in soil. The solution to Eq. (A.3} for the above Initial and boundary conditions Is where C - (H/Kd)CS0 * erf (_L) 2/t I*'6' 2n erf (n) error function 7* / exp(-n*) dn o The flux rate at the soil-air interface ((<*) can be estimated as a function of time from equation (A-6) by using the concentration gradient A-3 MOMS 224499 as follows: "A E*D iC E e1 1 >2 2-0 /not (A-7) The boundary conditions usad hart ara suparlor to those usad by Jury at al. (1983), assuming that tha vapor-phase boundary layar Is rate-controlling. Expariments by DuPont (1985) on amission ratas from contanlnatad soil show that whan tha amission ratas for volatile organics ara plotted against tha raclprocal of /*, 1 straight Una 1$ obtalnad. This obsarvatlon Is conslstant with tha ralatlonshlps glvan by Eq. (A-7), and Thibodeaux and Hwang (1982). Tha modal darlvod by Jury at al. (1983). basad on tha boundary con ditions of tha controlling boundary layar In tha air phasa, doas not provlda a straight-llna relationship batwaan amission rata and l/7t. for this reason, tn* reUkionsnlp darlvad In this raport Is usad for exposure avaluatlon. Th average flux rata, NA, over an axposura Intarval, T, can ba calculatad using Eq. (A-7). T ; Ha at A j>_____ T 2,,D1 H_CS0 noT *d (A-8) or Wa(T) - 2 NA(T) (A-9) To astlmata tha total averaga amission rata, Q, tha flux rata daflnad in Eq. (a-9) must ba multiplied by tha area of soil contaminated. A-4 MONS 224SOO Q`A `\ (A-10) Furthermore, while Eq. (17) in Section 16 cn be used at any distance x from th site to estimate air concentrations of PCBs, It cannot be used on site. Although at present there is no generally accepted methodology for estimating on-site concentrations from an area source, on-site KB air con centration was estimated based on a "box model" approach, by using the equation (A-ll) where H mixing height 2 m V average wind speed within mixing zone 0.5 wind speed at the mixing height 0.S x 4,5 meter/sec 2.25 m/s LS width dimension of contaminated area perpendicular to the wind direc tion 45 m A need exists for development of a more rigorous approach to estimating on-site ambient air concentrations. Time constraints did not allow development and validation of a rigorous model. Estimation of Ingestion of contaminated soil required the calculation of an appropriate loll concentration. This concentration was calculated by deter mining the average concentration of PCB In soil to a depth of or 25.4 cm (10 inches) for a period of 6 years beginning at time 0. Because the error func tion has no closed-form solution it was approximated by MOMS 224501 A-5 2. - o(2n*l) irt _iso j CP^ ~ cs n0 where Lite depth which wet selected such thet (A-12) Ct (L,t) Cjo for all exposure durations. In calculations reported In this report, L was set equal to 250 cm. Integrating C* of the exposure duration to ($ years) and depth t (25 cm) yields an equation for average PCB soil concentration, c7 *0 Cs _1_ / t0*i 0 dz F321S^CSn0 ibr /1i_COS(,"22n"+l n t\i (*-13) Case 2. The contaminated surface is covered with PCB-free sol' material. Let t thickness of cover, cm, and L the depth of contamination mea sured from the top of cover material, cm. The Initial and boundary conditions become: 1. I.C. C 0, 0 < z < i, at t 0 2. I.C. c c0. i < z < L, at t 0 3. 0.C. C 0, z 0, at t > 0 4. 0.C. *C 0, z l, >z t t > 0 where Co Is the initial concentration of PCBs in the vapor phase, which can be obtained by Cq (H/k^JCjq. Eq. (A-3) with these Initial and boundary condi tions can be solved usiny the Fourier Series technique. The solution Is A-6 MONS 224502 - -(2n*l)2 lt2t C 4Cn l 41* n n-0 sin {_2n*l n Z| ent{2o*l It | (A-14) The flux rate at the toll.air Interface (NA) can be estimated as a func tion of time from equation (A-14) co.(i2s$i>M) (-15) The average emission rate over a time period, T, can be obtained by inte gration of Eq. (A-lS). The result Is r na 8(H/ttrf)*CS0*E-0'el II ---- * v2T n0 (2n+l)2 az)ti a Un*l|Vn*)tjr cos(12nM_) nt) or (A-16) na t*T ,, 01El/3(2n+l)* nI)t, L y 1 [t- (l+l(`S)L2 -4----------n-0 (2n*l)z 01El/3(2n*l)* Ji)t2___ f(2rt*l)nii [TaK-si-iT-a--------- ^C011 --rr*' (A-17) A-7 MONS 224503 Tht summation of terms given In Eq. (A-16) can bt conveniently carried out by meant of computer simulation. The time Interval tj-tj should be set equal to the exposure interval. In calculating exposures, the maximum average expo* sure Mat estimated. This was achieved by calculating as a function of time and determining the time at which the maximum value of d* occurred; tj was then set equal to this time. It should be noted that when the value of the expression n(Zn*l> H in 41 2 the exponential term of Eq. (A-16) Is small or considerably less than 1, the average of the exponential term over a time, t, will be close to 1. In this situation, averaging of the exponential term of Eq. (A-15) by the integration formulae given by Eq. (A-16) or Eq. (A-17) may easily result In an erroneous answer because one has to evaluate very precise numbers of many decimal points for the values of the exponential term. It Is more practical to numerically average Eq. (A-15) than to obtain the average value by using the Integration formula given by Eq. (A-16) or Eq. (A-17)i * 9 (2n+l)* n*t - . 2(h/k,)C$0-E-0., | r , . rp ) dt-coslddjDJIf.) "L T n*0 tj (A-18) The steps of the summation and the Integration with respect to n and t, respec tively, need to be carried out by means of a computer. As in Case 1, Eqs. (A-10) and (A-ll) are used to estimate emissions rate and on-site air concentration of PCBs. However, Eq. (A-17) or (A-1B) is sub stituted into Eq. (A-10) as an estimate of flux rate. Also as in Case 1, the average soil concentration used to estimate inges tion of soil must be calculated. This can be accomplished by noting that C;q A-8 NON$ 226504  c0 xd/H, substituting this relationship Into Eq. (A-14) end Integrating the resulting equation over the depth interval t and over the time interval ti to tj + t0. The result is CO* J(I"+l)ltf ) ,[2n+l)g n(ti*tn)l - e 4-L^ (A-19 where to 5 /ears and " 25 cm. When the Initial PCB soil concentration used in estimating exposures ex* ceeds the concentration at which the vapor pressure of PCB is achieved, a different model must be used in both Case 1 and Case 2. The vapor phase PCB concentration that can be achieved in the interstitial voids in soil is limited to the concentration corresponding to the vapor pressure. While this limits the emission rate, it should be noted that as the soil zones nearest the air*soi1 interface become depleted of PCB, the emission rate decreases. If PCB is present in soil concentrations that produce the vapor pressure in the vapor phase, the average emission rate may be increased because soil near the surface is depleted less rapidly. In modeling this phenomenon it has been assumed that at any given time, tne concentration profile of PCB in soil as a function of depth is a steady* state profile. As in the previous models, the concentration of PCS in the interstitial soil void space is assumed to be in equilibrium with PCS soil A*g MOMS 224505 concentrations. Given these assumptions ana the initial conditions that where Cst PCB soil concentration at which the vapor pressure Is achieved. A mass balance can be written to determine the rate of depletion from soil. If the soil concentration profile Is is defined In figure A-l. this mass balance Is dz at r 7 C,,[P(l-EK*ICd/H]l Ps(l-E)(Cso-Css) (A-20) Because we assume that any any time the soil and vapor PCB approach their steady'State concentrations. C . o ii z (A-Zl) substituting equation (A-21) Into equation (A-20) and Integrating the result Ing equation over the time Interval 0 to t and the corresponding depth Inter val 0 to z yields the result A-10 MONS 224506 C O N C EN TR ATIO N IN ( O il D*TM (t) Figure A-l. Model of chemical vaoor movement through toil when pariiel pressure is equal to vapor pressure. A-11 HONS 224907 (A-22) As in the previous case, the flux rate can be calculated as ar r E'D_.'C.-'H (1A E*0 . E*D . o -]-- el x el z z ka or (A-23) d6a"' (A-24) If the average flux Is determined for the time Interval T, it Is easy to show that (T) 2N*(T) (A-25) As Indicated previously, Eds. (A-10) and (A-ll) can be used to estimate emis sion rate and on-site air concentrations. However, Eq. (A-24) is substituted into Eq, (A-10) as an estimate of flux rate in this case. The average soil concentration to a depth of 25 cm over the exposure duration of up to 5 years of exposure must be determined to estimate Ingested dose of PC8s. The equation used to estimate this average depends on whether the depth z In q. (A-22) 1$ less or greater than Li (25 cm) at the end of the ingestion exposure periods. The time T5 at which z is easily A--12 MOMS 224506 calculated using the following equation: Ts 0.25'Lj^" (E'Cjj - 2(l-E)P-CS0`Kd/H - P-(1-E) *CM*Kd/H)/(E-0#1 *C,,) (A-26) If the Ingestion exposure period, T, is less than 15, the depth, z, will always be less than , and the average soil PCB concentration, c$, can be calculated as follows: rs - 2-(C,,-2*CS0) {E*0#1 -Cls-T/CE-Cst^2(l-E)-f*-Cso-Kd/H - (1-E)*P*C,,-ICd/H]} /3Li CS0 (A-27) If the Ingestion exposure period Is greater than Tj, the depth, z. will be greater than lj at the end of the exposure period, and the average soil PCB concentration can be calculated as follows: Z% 2-(CJt-2-Cso) (E*0#^ *Cjj/[E'Cjj+2(1E)*P*C5g*Kd/H 0.5 . . - (l-E)*C,,*P*Kd/H]| `Ts1*5 /(3`L^T) CS0*T5/T * 2MC|S-L1) {[E'Cjt+2(l-E)'P'Cjq - (l-E)-P*C,,*Kd/H] / [`Dercss31 -5 {T0*5 - t5*51/T A-13 (A-28) MQNS 224509 When clean cover Is placed over contaminated soil, a similar model can be developed as in the case where soil is contaminated to the surface. For such situations, assuming that local equilibrium between vapor and solid phases and steady-state concentration distributions at any time are attained, the following mass balance which yields relationships illustrated in Figures A-2 and A-3, which define the concentrations of PCD In soils as a function of depth L4 - (2*Ll-(l-E)`P(CS0-CM) {A'tU-EKi'CCso-C,,)-?]2 *Lr2* (E -H/Cd (1-E)*P) 'Cjj"[2(1-E)`P*(C$q-Cjj) E'H/ICd (1-E) *P) *C,,)]|0'5 / (2*[2'(1-E)*P-(CS0-C,,) C*H/IEd*(l-E)-P3*Css3l <*-29) The time at which PCS reaches the air-soil interface, Tb, can be estimated by rearranging Eq. (A-22) and substituting L* tj. for z, as follows: Tb " <L4*L! )2-{E-CIS*2*(l-E)-P-Cso*Kd/H - (l-E)*P-C,,-Kd/H| -{4*E(A-30) Integrating Eq, (A-24) over the exposure time interval T& to T+T|, and dividing the result by T yields the following expression for the average flux over the exposure period: A-14 MOMS 224510 C O N C E N T R A T IO N IN COIL Figure a-2. Model of chemical vapor movement through toll whn partial pressure is equal to vapor pressure. A-15 MOWS 224511 PCB t o il C O M C C N rflA IIO N Figure A-3. Hess balance for vepor movement through soil when partial pressure is equal to vapor pressure. MONS 224512 A-16 / E`erC (2-(1-E)'P-Cso E*C,,-H/)Cd - (1-E)"P*Cjj / K^/H (VT)1/2- \Vl T (A-31) At before, Egt. (A-10) and (A-ll) ctn be used to estimate emission rites ind on-site elr concentrations. Pi nil 1/, the average soil concentration to a depth of 25 cm over the exposure of duration up to 5 years must be determined In order to estimate ingested dose of PCBs. The equation used to estimate this average is: (A-32) Calculation of the Depth-Averaged Concentration for Uncovered Surface We want te find the average concentration of PC8s In soil over the expo sure period. As time progresses, the concentration In soil decreases because of volatilization. First, we want to find the time when the emission rate at any time equals the average emission rate. We equate Eqs. (A-7) and (A-8). Then A-17 (A-33) AONS 224513 The mission rate equals the average emission rate at t T/*, where T is the exposure time (1 day, 10 days, or 70 years), and t is any time. From q. (A-6), the vertically-averaged concentration over a depth of 2 cm is: C H c 1 / erf(_i__ ) dz *d SO z Jo 2/3t~ A-34) or Ceson I: f o trf(_2__ ) <iz 2/ot (A-35) The Integral should be nuaerically evaluated at t T/a, T being the exposure period for developing health advisories, and at an appropriate dgpth within which the concentration average Is desired. A-18 MOWS 224514 REFERENCES (APPENDIX A) OuPont., R.R. (1985, Nov.) Evaluation of air amission release rate model pre dictions of hazardous organics from land treatment facilities. Presented at American Institute of Chemical Engineers meeting, Chicago, IL. Farmer, W.J.; Yang, M.-S.; letey, J., Dept, of Soil and Environmental Sciences. University of Callfornla-RIverslde; Spenser, W.F., Science and Education Administration, Federal Research, USDA. (1900) land disposal of he*achlorobenzene wastes: controlling vapor movement in soil. EPA-600/2-80119. Prepared for U.S. Environmental Protection Agency, Municipal Environmental Research Laboratory, Cincinnati, OH. Hwang, S.T, (19B2) Toxic emissions from land disposal facilities. Environ. Prog. 1:46. Jury, W.A.; Spencer, w.F.; Farmer, W.J. (1983) Behavior assessment model for trace organics in soil. I, Model description. J. Environ, Qutl. 4:5$B664. Thibodeaux, L.J. (1979) Chemodynamlcs, New York, NY; John Wiley and Sons. Thibodeaux, L.J.; Hwang, S.T. (1982) landfarmlng of petroleum wastes: modeling the air emission problem. Environ. Prog. 1:42-46. A-19 MOMS 224515 APPENOIX 8 EXAMPLE EMISSION RATE CALCULATIONS FOR FOUR STUDIED SCENARIOS Example calculations for estimating volatile emissions of PCBs based on the models presented in Appendix A for unsteady-state conditions, and under steady-state conditions are presented below. Case 1. unsteadv-state emission: no cover. The contaminated soil Is exposed to the atmosphere, and no clean soil cover Is applied on top of the contaminated surface. PCB-1254 is used as *n example. The average emission rate, which Is obtained by averaging the Instantaneous emission rate over a time period, t (sec), can be obtained by: where /*efcm2U(s) s with S . Del 0.0$ (0,35)1/3 0.0352 c*2/s 8-1 *0NS 224617 Hence: a 0.0123 0.35 2.65(0.65)1 . 0.0003*3 The average emission rate when the Initial concentration In toll. Cjj 1Q" g/g ( 1 ppm) can be obtained by averaging over 10 dayt or 70 years: 10 day ( 66,400 tec) average; 70 Ttart ( 2.2075 k 10s sec) average: Case 2. Unsteady-state emission.-soil cover applied. Clean soil is applied on top of contaminated soil surface. Emissions will occur through the cover material, and Mill remain unsteady below the vapor saturation point. The average emission rate under the assumption of the initial 8'2 MONS 224516 contamination depth, l 200 cm, can be obtained by Eq. (A-l3); - -wu/* r n.i -t NA 2(H/Kd)CS0-E-et i Jn[/ne t n*0 0 a (2n*l)2H*. --^1 dt-co*{<22illL| 3 For an average emission over a period of 10 days (8(4,000 sec) 2(0.000342)(10'6)(0.35)(0.0352) Na (200H864.000) . 864,000 _ 2.&10"6(2n+l? II e 47200)* n0 0 * . co# 7,6 * 10*H g/cm2,s , Similarly, the average emission rate over a period of 70 years 5 * 10*1* g/cm2*s NOTE: The emission rate equation is programmed in a computer, and the sum mation 1$ carried out using the orogram. Case 3. Steady-state emission--no cover. The same scenario assumes that the contaminated surface Is exposed to the atmosphere, and its surface is maintained at the concentration of interest over the period of emission. This will apply to tne case where a large reservoir of PC8s is available for emission until the concentration at the surface reaches 8-3 MOWS 22(519 the saturation value. This will be the upper-bound emission rate for contami nated soil with no clean cover applied. PCB-1254 0.34 Q/cm3 alr/q/cm3 water 1000 g/g soil/mg/cm3 water * 3.4 x 10"7 mg/cm3 air 3.4 x 10" 7 x 10*3 x 10` "fl/3 340 >.g/m3 Partitioned vapor concentration: 340 g/ie3 Vapor pressure at 2$C 7,71 x 10 "5 imHg C* PMW 14.7 (7,71x10-5/760) 328.4 8.5xl0- I/ft3 ITT 10.73 (460 77J where F - 1.8 (25) 32 77F, C* saturation concentration of PC8-1254 in #/ft3 or "g/m3, P vapor pressure. MU molecular weight* P gas constant. 8.510-8 C4S4) x IQ* ud 1362.7 ..g/m3 (0.3048)3 n3 When PCB-1254 Is greater than 4 ppm in soil, the partial pressure in the air phase Is equal to vapor pressure. An average temperature of 25*C Is used for evaluating the saturation concentration In the vapor phase. Since the vapor B-4 HONS 224520 pressure It dependent upon temperature, a specific evaluation Mill require a temperature of fnterett. The temperature In the subturface toll may not fluc tuate considerably over the average value. PCB-1242 Concentration In air above toll with 1 gg/g PCS 3*0 x 5.73x10-* 23.3 ug/*3 8.37xl03 Saturated vapor concentration 1362.7 4,06x10"* 266.5 5823.3 gg/*3 7.71x10*5 328.4 Note: When the PCB concentration In toll 250 ug/g 5823.3 the vapor phase It saturated. i In order to calculate the emission rate, the values for gas-phase mass transfer coefficients are estimated using the relationship given by Hwang (1982). PCS-12S4; kg 5.8x10-5 IB 0.5 (THTT) 1.36x10*5 g mol/cm* s PCB-1242; kg 5.8x10-5 ,18 0.5 1.51x10*5 g mol/cm* . s Mole fractions of PC8s In the gat phate (y) when the concentrations are retained at 340 ug/n3 and 23.3 gg/m3 for PCB-12S4 and PCB-1242, respec tively, are: 8-5 HONS 226521 PCB-125* PCB-1242 y 3*0 ug/m3 0.07*2 ppb/Ug/m3) x 10*9 2.52x10*** y 23.3 ug/m3 * 0.0916 ppb/(ug.m3) x 10"9 2.13xl0*9 Th* mission rat*, Q, can b* obtained front the formula Q HU'kgy, where MW molecular weight (Hwang, 1982). Thus, the emission rat* for each Aroclor is: PCB-125* PC8-1242 Q 328.* (1.36xl0*5)(2.52xl0*8) 1.13x10-1 g/s cm2 Q 266.5 (1.51x10-5) (2.13x10*9) 8.57x10-12 g/s c*2 Case 4. Steady-state emission--cover applied. It Is assumed that the contaminated site Is covered with PCB-fre* soil cover, and that the concentration at the top of the contaminated soil Is main tained at 1 wg/g over the period of emission. The emission rate can-be obtained from the formula (Hwang, 1982). 0 01 Pt4/3 C,* , g/cm2*s h where 0^ diffuslvlty, cm2/!, f>T total porosity, . Cj true vapor pressure In egullibrium with soil, g/car, h cover thickness, cm. using the dlffutlvlty value of 0.05 cm2/s, one can get for PCB-1254, an emission rat* of Q (0.051(0.35)4^3 3*0 uo/m3 1Q-* q/ua , iq-6 CH|3/m3 25.4 cm 1,67 x 10"13 g/cm2*s B-6 HOMS 224522 Similarly, for PCB-1242: Q (0.05) 35)4/3 23.3*10" * 10* 1.14xlD"l* 9/cm2 f * ' ' jl.* 8.7 MONS 224523 REFERENCES (APPENDIX B) Huang, S.T. (1982) Tonic emissions from land disposal facilities. Environ. Prog. 1:46. MQMS 224524 APPENDIX C SUMMARY OF COMPUTER RUNS FOR EACH AROCLOR AND AT EACH VALUE OF SOIL-AIR PARTITION COEFFICIENTS MOMS 224525 C -l (AMI C- I. KMISSItU CO*lM* M>1 CMIMHMIIM 11*1 St (UaUMHO SMMCt CMIMIWIIM, l| IMS) LhiIIm tit rwtt t* hmw littttn ItKIKIf iMfl-ttf** tctwirtlt Iwtrtt mfi* ins Itr (MI4 ns far itatt rtfliilUt Ititli lit/tl tKfnmUlni la ______ Cmtf flit ittclflt tun .Min lit*' rltt) (.fin f.irt i.n (!** rIM) ( rlu) (IO-*rlit| ta tkt ttMMlMIH lit* - Sill lntUlta(, Intilit lit* - Sill laftttlaa*. IMilltlaa* - IMuIttlta talr* lit tit 2IM ti t.OM 0.M O.f 0.M t. t t.t t l I to m 0.1 ta 1 rm CMttaltitta tilt luMlttlaa aatji* 1 la traa caatialatttO lilt - IMwIil l aaljr* ' n ti fl lot I.Hl** ti US l.ltlO* n ti 'Shart-iara * li-ttji latita. hint (ftrift mIMi tMt Mi n If Itr * (klli Mi tit Malt, ftifttllttly. CMlim tftt M, >IU fUt (ttntMtf 1 tll/tir>. ACMIOrta ifM !*, attllwt tlti (crnttMitf O.t f iall/t/). tlithtlttlaa riltt If tlMMi It bt M r/M far IM |trtltra MS Iffir-ttf MaciKli HMWti; II MMr (ttrt chraalc) aipatarai ttwai ti fca M t/Mf ti t rmll ti Itt taptttrt tar jrtir, 'tt MuMti m thttrttlul ttftr.httti Halt. IrKlIttl rttttat r*alr frta-fltalaf ft* lltili l tkt Halt. *ltll>ilr Hrtllla tttfMtltM t.H 10*' f Mll/ci1 ilf ( N.tl/tj I.IJ I 10** (tll/UNO l. I0-|. MONS 224526 20 rti c-j. kmissiou rct-mj soil cmimuhiioh unit** (IMCOKMO WRMCt C001MIMI100, 1* *0> rwltMl>arIlMK Kwtr th*rt-t*ra* WrtU IjltlLUfto* too f*r [MN mo Ih *0*tt ?*m1ii1H* la*it (i/ol ikTMMaOl-- I* ____________Caattf MU Mwlflt OWt IM/PH) o.oow (!*' rltO o.m f.m i.n <10** rltf) (W* MU) 111'4 Mtl) Oa Uw (MllllMIri tit* . loll laftttl***, fiOuIttlM* - S*l 1 ItlllllM*, lMI*tlM* - liOwlatlM Mir* M 147 ' 140 mo n . I.M l.l 1.0 II 0.3 3.0 .4 4 110 0.1 la IrM coatMlMtrO tit* - |M*l*tlM Mir* 1 la IrM cMt*al**t*0 tit* |iOtal*ttM Mtjr* I *4 vt n 4 no 1.1*10* ft 111 3.1*10* t *1 Shtrl-ln* 14-4*7 latOi, hnM m (**r*f* *!#** *0 II N R l| I* i chllO MO M Malt. rM*KtImIjt. 'CMIOtm IM 1*1, alth pit* (CMtaalaf ] ( t*ll/0*rl. *CMIOr** *** l-S, ItMwt pit* IcMVMtu* 0.4 * t*ll/0*r>. IM*ltlM rat** art HllH It k M a*/47 1 *r ttM Ittrt III* MO lk|lt`ttr* NKlMtf ntturii; ill HWr (mti iMalil tittwrrt mmt t* 0* 10 *% II r*t*>t ol III 0*rt tifttan Mr |lir, rTi ItMItl M tM*r*ttc(l M*r >-- Halt, ktclldl rmm r**lr* * (ra-n*l* rc* ll***0 tar <* I tall. *lall.*1r MdltlM CMtriclMt 1.3* I0`* f Ml l/C** *lr ( N.4I/U t./J II** (41)/I400 1.1* !'*). MONS 224527 IhiUm rwt * ***** ti**W imcNcir ** im*t H/to> 100 Ur chi I* JO* tor Unit PfralttlH* Iwll (--/! 4*rr*tKli f ____________Cmcw mu wfcu ***** I--/*) .tom (W* rt**) i.*m a.tn i. (I*-* rttt) (** rl*l (|*-4 rlU) On lh cMlMlmlri ill* - Soil l****ttliC, Inhllttlhh* - toil imu|n<i UMI*ttm* . UhwlM In hhljr* 41 4J ? TWO vs O.il 0.04 *. 0.1 1 o.t t *.* 4 I* 4f II* 0.1 la frm cntnlMlH tit* - IhiitMln *Bljr* 1 ta fra* UHtMlMtt* III! - Ii*illttn *hljr* f*( ft rt ft 1.1 II* *,J*0 .111** fit f.l** ft ft *siwrtairt l*-4*f ln(*t. Hitt* firm l*ti l ) If chit* ** m Whit, mphcttmljf. tChllhrm *** 1-t, alth *lc* (cmtiml** 1 t t*ll/**jr|. *Chll*rt* m> l-t. tlhmt *lc* (ciiIh M * t*llj**y). | t|*h(l*tlh rittt in ItuW llltlt I hr th* tmt'liu ta* I--fir -tr miKir *; II Mlwr |an curtate) pathrtt niml t t* 1* bV**jt II null * 1*1 **f\ imun **r r*r. I ft ItntUt Mh UmHICll mcctlol Halt. Iritlllll riiHM r**alr* *h ffm-llmlh* III Itml* fhr th* llhtt. Hall-tlr MJtltlhh cmfllclcat I.J* I**' ( thllVch' *lf ( *.*!/*( *.JI If* (DJI*** * J, 1 in** I. il i HONS 224526 tn c-i pfnmiHi pc*-I2*o tail confM*fion tints* (1C0n(0 SOPf l COOIMlMf 100, lt 441 iacatia ta* raut* al Nwata aapeiara hMMur itart-ttii* atctatatl* iwm /<>* IDO far CHIN /OQ f#f atult fammlSIa lattlt <--/) wnmnlw ta ____________Cantor rltt itclttc 4wi I--/Par I o.mn (I0*1 HU) o.oi n f.lft (It4 rltb) (* rltll (10 On tn# caataalaata* 11ta Sail laprttlaa*, laPalattaa* Sail taytitIan*, Inaalatlaa* laPalattaa aalp* (0 ISO n' no 2*00 *9 0.01 *.** Ml 0.1 1 * 0.2 2.0 11 0.2 2.0 0) O.i ta fraa coataalaatat tIta Inaalatlaa aalp* 1 ta fraa cantaalaalaO llta Inaalatlaa aalp* VI 99 99 99 1.0 *0 0,100 99 no 2.Sal*4 99 *Start-Un f IO-4ap latita. HnM tftrif* nl*Hi af II 4 II l| Iwl cOllO aao 4U, ratpactlaalp. Cc*fl0raa apat l-S, wit* pica (caaiaalaf 1 tall/Pap I. *chll4r*a M l*S, wttlMwt plea |(nW|4| .* f tail/Pap). * Inna I it Ian rat** art iiimI ta bn 20 a>llan far tha abart-tara aa4 laaftr-tara nawaatir all atkrr (aara tlraald aaaatwrat aiinal ta ba It r/4* at a ratal! at lit 4*ji tapatara par >tif. Ii dawatat aa tbaarttUal apaar-bawa* Halt. Practical raataat rtaalrt aa fraa-flawtap Kt float* far tba Halt. *Soll-alr partltlaa ctafllclaat 2.J* a W' f lall/ca* air ( H,4I/K4 S.2J a If* (4HM0O* 2.IS IP-*1, HONS 224529 II > gi i Hull C-S. rtM'ISSIIU PC0-US4 WIL COMMiaul lua LOUS* luaconu* swroct cmimimiiw, ioooi lacatlaa aatf rut* If haaaa aapaapra ftasctacar ihart.tanai ccaatahla 1 atata na/tau* IN far chi II no far aaalt Pttalaathla laialt Isa/al carraaaaatlsa ta Caacar rut taaclflc fatal (na/fail o.ooits do*" rlitl 0,alts [.in 1-1* (It-* rlul |10`> rlUl (It-* r|iaI 0* tta caataalMtat alia tail lafaitlaa*. Itaalatlaa* - Salt Isaaitlas*. latalatlaa* . mail atlas aafp* It SIO It' no mo rt 0.01 0.04 t.tt O.i 1 0.4 4 0.1 7 II s* 4M 0.1 ta fraa tastaaltatca ilia - Isaalatlaa aalp* 1 la fraa taataatsstat tlta Isaalatlaa aalp* n tt ft n 1 I.IllO* 4M 4. tilt* 4.tilt* 1.1*10* H ft Start-tiro f I0~4ap lotflta. Iim iMri| af II m ft It far chtlf at as afatt, niciliil|i> cChlltrm l-l. wit* pica limnlii ] tall/tapl. contras tn |*I, stthaat pita (tamualst o.t t Mil/tap), * IsSal ( las run art IIMM t* k* ft m*f4ip far lla llurt-lwi Ml liqir-lin mmmcit aipaiarat; II attar (tart chraalc) iifiMni iiiim! la ha It avtap at malt ar Itt lifi aapatura par rr. it aaaatat ta ttaaratUal aar oauai Halt, Practical ractaat ratalra na fras-flwlaf ftl Dealt far tta Halt, tall.air partltlaa caafflctaat I. It** Mtlfca* air ( N,4I/K4 t.fl It"' |41|/ltt I.It a IO-`l. MOMS 224530 TAM.) C-4. KMISSIOM RCO-ltM MIL CMIMIMTIOa ItniS** (UHCmKO SWKt CM1MHMIIOM. l4 40) iKfllta Mi rg*ti ( hiata lifWirt IwcMcir (Mrt'ttrw* KCMtMll M/itt* ioo (or till t4 no for Mill )oli_(jo) wrowaOtoa t* CMKRf rltk MKlUl MW Im/MI i.wn (It-' rift) i.n o.iti i.n (-* rltl) (-* rltt) <!** Hit) Or IM cmImIiiiM lilt Jolt iRfMitfa*. lahlttllRR* * tall laotUlRR*, IliMltttRB* . irmIiiIm *!/ too AM tf 730 30M ft 0.000 o.ot o.ot o.oo 1.0 11 o.t ] M 0.1 s Iff 0.1 ka fra (RRk(alatR0 tilt . itatitiiM mI|* 1 la fraa ctattalMItO tilt - IMlllRitRR *! Tt Tt ft ft t 1100 oro 4.;>to* Tt l.ltlO1 Tt Tt Start-ttr* l-4*r IMOI. HnM m Ittrtft Mlpll M M MO 10 If fir I cRtIO Ml m 40ll, ratfttlItaly. Hr114rMl ifM 1-4. aUR Rill (CMltoalRf 1 0 tttl/Oqr). *CRllOrw *f*i l-. wttRaat *lc* ((MtaiRi o.O tatWOar). iMttlfllaa nlM *r* wm If M ill aVAt? for tRo ilnrt-lm tao laaftr-itra aaactactr ti*ttrt>; II attar (r eRraate) HMUm iiimM It R 10 tt * ratal! tf 101 4tyt tiRtVtrt par pair, 'ii Oaaattt * iRRaritUtl aoor>Ra**0 Mali. Practical rtiMM rtRRlrt a* rnollMlM ICO Ilil4 for tht Halt. *lall-*lr MftlllM CMffUtaRt I.It i to** ( Mll/ca> tlr ( 11.41/0* 4.11 I 10*1 i. io*M* HOMS 224531 LkIIIh Mi r*rti af haaa* iitari _______________________________ fki*m*!*-t**ti-(k/k> nrrnmtlw ib___________ _ MKNKtr .kart-lira* iccmiklr HUM it/BlJ* Cnwf Mit BBktlflc W lak/BM) m far chit* too far 4vl o.iom (!*' flrtl Min p.iu 1,1* (l** Hit) (l*- Mil) (I*-* Mil) M lit taataat**t*B 111* dll dfritlBk*. Inks In In* - Skll tkdltlak*, IdklBtlkk* lf*Blitla Bkljr* l Ml r n k.kt k.kt 0.0* *.l 1 O.B B *.* II Bk 11 0.1 la Irak taklkaiBBtak Ilia - lakBlBtlaa Bkljr* 1 la from caklaatkatB* ilia ' Inkilatlak Ml/* n n n VI 4 It UI0* * IB* I.IllO* t* * 'SMrt'tm t l*-4T IDIti. Hiii w tivqi mkI^Ki af la aai to tf r* cilia mk m dill. nuttUHlii, <tMlin in !(. ilk Bid I Mtl/Mjr). *tkllkraa a*at t-l, wltlwiit pit* (cwwalBt l.i ( ull/iij). ImiIuIm riln in miwl IB ks 1* */> tor Ik* dart-tad Mi (wtHcif Ufiwii; ill itkBr (akri tkraalc) iiBBtam iiimM ib kk Ik 0*10*1 * I radii if Ikt 4*jn tiBawra for i**r, In Bawatkl *b tkaaratlcat opfor-kmuO Halt! Britt Itil rBBBBM raaalra m I rvt-flMl*f BCt I lull far tkk Halt. **Bll*tr iirtltlM cakfrlclBM I.ft Ik'* ( lall/ta* Blr ( H.ll|t| t.ll Ik'* |4l)/IUkB I, i 10**). HONS 224S32 Ttoit c-o. kmissiiu pci-im sou cMrwiMriM mutt (IMCaHUO SWfKt COOJMIOOIIOO. 1 OO) iKtllM M root# of dm iifntn IncMcir mwrtu iQtoio i/oct* wo tor toil* wo tor oOoll HnlwIMt Iwll Wil UfrwwULw U twwf flu wwliu <mi Im/nn_________ o.ioift (If*' rl*t) o.fin t.iu i,n (If** rift) (lf- riu) (10** rltl) Oo IN cMwlMlM ill* - Soli loontloot. |o*olotloo - toll 1 opoittoo*, loOoiotloo* - looolttloo ooly* ft MO rt 7| 0.01 f.fl 0.1 1.0 it 0.1 1.0 <0 0.1 1.0 It 0,1 lo troo cootoolOOtoo lit# loHolotloo ooljr* 1 lo troo cootoolootoo lit! - 10*01t loo ooljr* *1 *1 n 1.0 H noo r.tiio* no t.Illf* *i n `iMrl-lM* ll-ttf lototo. tfoiof o* Ivor** ool*t it II m II If tor dlM w oo oOolt, roooottliolr. *CMI0roo ifof l-t, oft* pic* (cornua!** 1 t Hll/iif). *CkllOroo *fo* l-l. irtlfoot ftco (loooaolof f.l f lotl/fop). oifOwIttloo rotoi rt iimM to 0* 2* ?/0or tor too |0ort-toro mo loooor-toro omcokot oifotorot; *11 otoor (ooro cOroolc) oipoiorot nooM to ko If *?/0op oi o molt ol lit Oort oofoooro por poor. r*i Ooootoi oo tkoorotlcol *por Oi io0 Holt, ProttUol rmoo* ropotro oo troo-tlooloo fCO 100II tor tOo llolt. tJoll>tlr portItlto cooftUtoM 7.* lf`* toll/to* Mr ( ./ l.tl o 10** Ml>/Iff- t.J* t lf-`l. MOMS 224533 C-9 ThlllC C*t. fCMIMIOlt PCt-1747 MIL COOIMIMTIOM Kttlll (It'Ca-lHICt CUW Mil COWI. I4 IMt) Locallaa at! raata af kaaaa aaaatar* kaacaacar ihart-Lara* accaaiabla I Mata /**! IN far chi la no far alalt Paraltathla la*alt (na/a) carmaaaOlaa ha Caaear flU itaclflc aatat |aa/Oa*l 0.001 ft CIO-' rirt) 0.01 ft .in i.rt (10* rich) (I0*1 rlrt) (I0*4 rlih) On tka c*fit*alaat*4 lltt Soil ln(aitlaac, lahatatlaa* - tall Itaaillaa, lahalatfaa* lahalatlaa aaljr* MO Kl *. 1*00 tno VI 0.1 0.1 0.0 t If wo 1 40 744 t m rt 1.1 ha fraa caataalaataC alia rt VI M rt rt rt tnhalatlaa aalj* 1 ha fraa caataalaataa tit* VI VI VI rt rt rt lahalatlaa aalF* 'Uwt-lini 10-Oap IttM, HataO aa mr|i wi0itt *f it aaa 70 t( far a chi la mm a* a*tlt. ratpactinir. `Chliaran 1*1. alth lca (caatuala| 1 Ml I/Car). Chltaraa aftt l-l. altfcaat pica (f a*tnnl*0 0.1 0 Mll/Oap). Inhatatlaa ntn ar* iimm lik II avcar Tar tka thart-tara aa4 laaar*tara naacaacar UMWII; *11 athar (aar* chraatc) (Tatar** iimM ha ha ! *,ya *1 4 ratal! *1 Itt a*n aipatara tar grair. (* aaaatat a* tkaaratlcal *aa*r-kraM Halt, Practical raaiaat raaalra a* fraa-Maala* PCI llaall far tka Halt. *iall-alr aartltlaa caafflctaaC <r.M a ll`* a Mllfca* air ( H.4tyc> * *-fJ 1 l*' (411/1000 7.W to*`|. NONS 224534 C-10 TM>[ C-IO. PtmilSIKI PCI-lt*t SOU COktMIIMtIOB Ltni.it (H-ca-mitt cum uni con*. i* io> LkiIIm *M root* *1 ktMM iifiwi HMtMCir sk*rt>t*ra* *Wt*t*t *VHl* IOB <W tkll* ra It t*.lt t*rai*iti* itwii (m/i) tifft--tin t* _________ Cxtw nn i--title <wt l--tin) O.OOin III"' rlit) t.tin t.us |.jj (If* rlit) (If* rlU) (It** rill) Ok tk* c*at**tMt*0 tit* - Sail ln*kttlMt, lk*l*tl*a* Sal 1 laf*itl*a*( IMwIitlW* - |kk*l*tl*a *) m 4u 1700 )W n 0.0) o.t 1.0 a) ).0 VI 1.0 l? VS ft vt rl 0.1 la fraa c*at*ala*t*0 tit* n n *t vs vs VS - 1ak*l*tl*a *atr* 1 ha fr*a cwt*alk*t*0 tit* . vt n *t VS vs VI - IkktlttlW **t* *ik*rt-Um 10-Ow Ikttk*. *0*t*0 m t**r*|t MlfM* ( II Mt II t It i tkMO Ml m *Mlt, r*to*ctl**ly, cCkll4r* H<1 1*1. *lt* kit* (ctatualaf ] f t*ll/r), *CM10r*a **t l*i. attkwt ole* (untaal** 0.0 * t*ll/0*r), ink*In I run *r* IIMN it k* 10 f/4*r (*r tk* iHrt-llft ml l*#**r-tra HKHCir !**rtl; II *tk*r (**r* ckraatc) H*(urn iimH t* 0* l* av*y M malt ( lit 4*fi *ik*t*r* **r j**r. '*t HmIH m tk**r*tlc*l ikk*r IkiH Halt, tracttcal rHMi r***lr* m rrM-llatln* ICO 1I*U It tk* Halt. *S*ll>alr MrtltlW ctalflclaat t.Jt If* | tall/ca* *lr ( N.ll/Ij t.F) i 10** (4I)/I000 I.H i 10-*). i | ! * HONS 22*535 TMnt c.ii. icmissiotc o-U4o mil coaiMMatrioa uvast tn-M-mcK cum mil tmi, t4 iom) Ltttlltf tfO mil tl MM iMMn MtMCir itert'lM^ **<* mm M/M* IM far cam m far afalt HfMim_iii_iMoi_o_<i/ol w'lwxm u ____________ Cpocor rut ifttlUc MM <ao/U) o.Min do-'rial 0.01 It (10** rltt) CIO-^>' r.ilnU) I.H CIO-* f I* IM (MtMlMtM tit* Sail laftltlta*. iMtlatlM* - Sail lafaitlM*. laMIttlta* - IMtlttlM tflr* IN' m *% IJM 4M n O.M 0.1 l.l 1 10 20 1 10 1 1 14 10,400 0.1 to fr*a caataataMaO tit* n n 14 II.OM n ft lailttla aalp* t ta Ira ualaolaitaO til* w% n ft n n ft imittim a*i* SMrt>ttra t lOUa* Iftatt. HttaO aa mIMi if n hi N i| Im cllio to4 w MK, ntf*tti**ir. `caitorto *** i*i. mUi flu (ttavaiao i tati/o*fl* <citllna HH I-I, altli* flC* |CMlf 1,1 iMulMlu rHn *r mhM U ft It f*/0af l*f tha (lart-lin mi lfMm uuMir ill mmt |w Unfit) iifffn mmM U M It whin rawIt tf IM **r* HMWi f#r aar. I*i itaatat aa UMntlul tpffr ft*4 Halt. frattlcil rnun ntiln m fu*-nrl*0 ref 11a**4 far im IMt. *Ul1-t1r flrtltlff ctafflctaat *.JI i !** f ffll/ca* tlr ( Jl.tl/t* .M * If* (41)/I0M I. I0*). HONS 22^536 imu cot. icMistiati ko-imo uti cmiwimmm itmsi <-ca-1N1CK cuu wii cm, 40) Lacallaa *a4 raat* *f haaaa aapaaara toaeaacar al art-tara* acnaMii 'lalak* .0/4*1* 10* far toll* 100 far *4a1t NtottaiOia !* (**/) carmaatotaa t* ____________taaar rial aaaclflc aaaaa (H/al o.ttin (If' rial) o.tm l.tn i.r* (If* rtati O0-* rtrt) 00'* rlit) Oa lha caM*k1**t*4 alt* Satl lapattlaaS laaalatlaa* tall lafaatlaaO. lahalatlaa* latialatlaa aaljr* l nf Ft 1100 Ft Ft 0.01 O.K o.w 0.1 1.0 4*0 0.1 1.0 iw 0.1 t.o I.OalO* t.l aa lr*a c**taal*tt*4 alt* lakalatlaa aalj* 1 to fra* c*at*Ma*t*4 alt* itoalatlaa aaly* Vt It Ft t.o l.talO* Ft Ft Ft Ft Ft It dwI-IHl I I0-4| IMM. Him a*r*t* *!** *f 10 M4 7u t far t cfcH4 4 m Malt, ntmiflf. `Cktiara* a**t l-l. attfc pic* (caattot** 1 M*l/4*t. *CkH4raa *f*a l-l, attkato flu [hhMm 0.0 a*itl/4*p). *l*fc*1*tl** run *rt HUaN t* ta It */*? far tk* Ikart-ttr* aa* laafar-tara aaacaacar aapaaaraa; *11 Mhtr (aara ckraalc) iifMana iiuaaf t* ka 10 */* at a raaalt *f IK 4*r* aapaaar* par fair. '*1 anataa aa tkaaratlcat a**ar-kaaa* IMt. Practical raaaaa* ra**1r* aa fraa-flaatap PC* 1|*al4 far Ika Malt. $*ft-alr partlttaa caafflciaM l.M a If* f taO/e** air ( 0.41/1* i.Ji a If* (40/1010 l.H a lf*l. MOMS 224537 c-n wit c-ij. **Misstate rco-irs* son cootmimtioo likui (fSto-INICK CUM SOU COVCO, 1* 1000) IKMIM to< root* of IMM mtn !wlnOli lmli (M/O) MWUMIO to ItOOttOCOr Ilnrt-Wl** ctMUOlt iMOt *J4n> ____________Cttstr rtt toottflc ow to/0*l 100 for chllo NO for o*U 0.001 N )I0*' ria) 0.01N O.IN l.?S (SO** riot) (tO-0 rlit) (10*4 rln| 0* th# c*ot*olo*t*0 lit* soil taoottloo*, loOolotloo* - Soil lofoitloof. looolotloo* . looolotloo oolr* iao IN **' mm ft o.ot o.oc 0.00 0.1 1 ft 0.0 0 ft 04 1* ft 1.1 to froo tootiolaotoO til* . Ink!lotl*o oolr* ft 10 to 1 to froo coottolottoO fit* to ft *t H IMWlMtM Nlft ft ft *tii* m iirwaiouof W *M N to for * drtto m *o Mil, rwoocilwlf. `COlUroo *000 l*. Olio flu Itioiiioloo 1 0 toll/oor). CtltOr** moo 1*1, otltNot flu (cooMt0 0.0 0 ** l/0*). *i*o*i*tt*o rotoo oro monnO to o* 10 o^/Oof for UN tOon-Ufo too lo^fiM ooottotor Moonti ill otOor (oor* tkroaic) iNHoril MUM to Oo M r/fOf N rooolt of 101 **ft oapoooro oor jw. '** Ooootot oo iliiritmi Mpoir lmi Halt, froctlctl unto* rooolro oo froo-Mooloo K0 Hail* for too Halt. Holl'Olr portltloo toofflcloot t.M i 10** o #tl/co* olr ( l,tl/>* Ml * 10** (0l)/l000 I. 10**). NOUS 224538  to Unit C-U. *M1SSI0L( Kt-IIH SOIL COUlWIMUM LEVELS* (2S-ca-telCC CUM SOIL COKI. It 40) lacatlaa m0 rsat af Obm *ifara OKiKir ikart>ura* uutSaOla Krt*4 M/0Ur> too far utla TOO far Malt NrtllllUt ltwl lat/ll tarraiaaaOlat tt ________ Cww rtlt imlllt <HH liti) o.ooin (10*' flat) 0.01 ft 0.12S 1 (10** rtit) O0-* rill) <10 Oa ska caattataasao lit* - Sail iHfastlaaS, tatalatlaa* Sail laatstlaaO, iHfctlatlaa* lahilaslta *)?* 140 VI VI 0.1 Sa fraa (*HS*ala*t*0 tit* laMlatlta wlf* 1 fc frw CMlMtNtt# fit* - laMlutm *! ft ft *20 V* ft ft ft 0.01 0.1 I ft o.ot 0.2 * ft o.ot 0.2 10 ft 10 ft ft ft ft ft ft ft *0*aa0 a* 4wh* mim* *f 10 hm ft lo for 4 ckito aaO m 4*H. raif*tti**ir. `COUOrtH 40*1 1-1, Mtk flu It4-ul*0 1 | Mll/4*f )- <CMI4TM *f*l l-l, alLOtaS flu ( wwulf 0.0 Ml 1/04?). latilitlH rt*i r 4ttnml ta h- It arlity f#r to* ttart-tlf* 40 1*Hf*r-t*ra mdchcw aifawrtl; 11 *tk*r (oar4 cfcrtalc) itMuff' 4m4 tt tt M 1/4fr 44 4 ratals *f 102 Otrt tiftiart far r*ar. f*t aaaatat ttaaratlul ffar-Ou<M4 Halt, fractlul rattaat ratalr* M frat.I)*!*( K0 Hall far tOa Halt *S*lt-lr f*rsltlaa tulflclaat |0'> f 1*11/ca* air < IMl/Kj S.f] 10** (4I)/IOOO 2.IS > 10-M. HONS 224S19 Unit C-15. PEIMISSIIU PC0-1MO SOIL COOTMIMTIOO UWlSt (zs-ca-thick cum son con*. ioooi Lac atlaa aaa raata af kaaaa tifatara Haacaacar taart-tara* t*ltkii lataia mviii* 100 far call* TOO far adult paralttIbla lavalt (a/al carrataaadlaa ta ____________Caacar rig aaactfic art** (*/al 0.001n HO*' rial 0.01 ft l.lft l.fl (- rltt) no-* rtlk) CIO-0 risk 1 Oa tka caataalaatai It* - Sail laaattlaa'. lakalatlaa* - Salt taaaitlaa*. lakalatlaa* lakalatlaa aalp* IM SM 1100 4000 It O.K 0.0f 0.00 o.t 2.0 It o.f f no o.t 0.0 710 0.1 la fraa caataalaatad tit* lakalatlaa aalp* 1 la fraa caataalaatad tit* lakalatlaa aalp* H n Vt Vt 0.0 710 Vt Vt vt rl VI *1 *$Hart-t*>* t lO-Oap lataka. Sllri M inrt|i mI|Mi if M w A t| (ir t dllT Ml M Matt. rmaacttralp. `CkltOrao *fkt 1-1. altk pica (c*a:*alaf 1 l*H/a*p) . *CMIraa hm 1-1, attfcOBt ptC* (tMMMiaf O.t MllfOtp). IihiiIiIim fun ar* iiMMi nhH aVCap far tlM Mrt-lifi of laapar-tara iwmiif *aiftt: II MMr (am Chraalcl Kutr iiuaM ta ba I* rffif at a ratal* af IK day* aapatara far raar. (y, aat*t aa taaaratltal taper-konad Halt. Practical raaaaaa raaalra aa fraa-Maalnf PCI llpald far tka Halt itll-alr partlttaa caafflclaM > f.Jt * "* | laU/ce* air ( H.Cl/Kj t.f] 10* (411/1000 I. **. MOMS 224540 C-16 (WE C-ll. KHISSim Kt-tlOO SOU COatMtMIlOa LEVELS* (IS-ca-THICK CLEM SOIL COftl, Kf 40) Lacattaa aao rente af kaaaa lift*art Wmkmc r tkart-tana* KCMtlkl I 1ataka at/Oat* 100 far ckl10 M far aOalt feralitffcta lartlt lak/l carrataaaOlaa ta taaar rltk tfaclflt Oatat (ta/oar) o.toirs (10*' rltk) O.flfS I.IfS (10*4 rltk) (If* ntt) 110** rltil Oa tka caataalaetaO tlta - Sail lefettlaa*. lakalatlaa* - Sail lafaitlaa*. lakalatlaa* - lakalatlaa neljO 110 00. ' 0 H00 Vt 0.01 *.** 0.0* 0.1 t.t MO 0.1 1.0 ISO 0.1 1.0 010 0.1 ta free caataalaataO tlta - lakalatlaa eelj* 1 ka fraa caataalaataO tlta . lakalatlaa eel/* n n It vt 1.0 010 Vt Vt vt vt Vt Vt *Skart-tare t II'*; Intake. HetaO aa inn* aalfktt af 10 enO TO tf far a cfcll* *aa aa aOalt. rttfectletlf. cClil lOrea eyet l-S, atto flea (caatwkaf 1 f telt/Oar). OCktlOraa eftt 1-1, altfceat flea Icanine!at 0.1 ( mIIMi). *lakitattaa fakai ara hmm ta aa 10 r/Uf far Ike inert -Lara aaO leaftr-tara aaacaacar eafetarett all atkar (ear* ckraalc) iifeiam iimM ta Oe 10 r/Uj at a retail a* lOt Oaft aifetnre far jeer. oaaatat aa intern leal aaeer-kaaaa Halt, met leal reeteaa raaalra aa fraa-flaainf ko Ila*i0 far tka Halt Hal I-air tertltlae caafflcteat l.M i t** tell/ce* air ( N.el/Kj * *.U >** (l/l00 t.Jl i I**1), MOHS 224541 APPENDIX 0 HEALTH ADVISORIES FOR PCBi IN SOIL Prepared by Michael L. Oourion Environmental Criteria and Assessment Office Office of Health and Environmental Assessment U.S. Environmental Protection Agency Cincinnati, Ohio HOWS 22*5+2 APPENDIX 0 CONTENTS EXISTING GUIDELINES, RECOMMENDATIONS, AND STANDARDS . ................................ NONCARCINCSENIC EFFECTS ....................................................... , ............................ QUANTIFICATION OF SHORT-TERM HEALTH ADVISORYLEVELS . . . , .. ................... CARCINOGENIC EFFECTS................................................................................................. QUANTIFICATION OF CARCINOGENIC RISK .................................................................. SPECIAL CONSIDERATIONS............................................................................................. HigH-Rlsk Subpopulation.................................................................................. Cocardnoganaili, Initiation, andPromotion............................................. SUMMARY.............................................................................. ... ...................................... REFERENCES..................................................................................................................... D-Z 0-4 D-l 1 0-14 0-17 0-20 0-20 0-21 0-21 0*25 0-1 HOMS 224543 EXISTING GUIDELINES. RECOMMENDATIONS. AND STANDARDS The manufacture, tale, and distribution of RGBs have been restricted under Section 6(e) of the Toxic Substances Control Act (TSCA) (R.L, 9**469). RGBs were restricted to sealed systems as of 1977. and manufacture and distri bution were banned In 1979. Rules for the disposal of PCBs were proposed In 1978 (43 FR 7150). The U.S. ERA (1980) has set ambient water quality criteria for RCBs for the protection of humans from Increased risk of cancer over a lifetime of 10*5, 10* and ID"? at 0.79. 0,079. and 0.0079 ng/L. As a result of the large bio concentration factor In fish, these criteria apply regardless of whether expo sure occurs through consumption of 2 L of water and 6.5 g of flsh/day or through consumption of fish alone. The Rood and Drug Administration 'FDA) has set temporary tolerances for RCBs In food and food related products, as shown in Table D*l. Occupational exposure limits for PCBs have been recommended by the American Conference of Governmental Industrial Hygienists (ACGIH. 1980). and criteria nave been set for PCBs In workplace air by the National Institute Occupational Safety and Health (NIOSH, 1977). The time-weighted average.(TWA) and short-term exposure limit (STEL) for Aroclor 125*. are. respectively. 0.5 and 1.0 mg/m3, and for Aroclor 12*2. 1 and 2 mg/m3 (ACGIH. 1980). The NIOSH (1977) criteria* Is 1.0 ug/m3 for a 10 hourt/day. *0 hours/week exposure. The National Academy of Sciences developed a 2*-hour suggested no adverse response level (SNARL) for RCBs of 350 ug/L based on the Induction of mixed-function oxidase enzyMS In the liver of rats administered Aroclor at doses of l to 2 mg/kg (NAS, 1980). For this analysis, an uncertainty faetor of 100 was used, since only enzyme Induction was reported In this dose range. 0*2 TABLE 0-1. FDA REGULATIONS FOR PCBt Commodity H11k (fit basis) Hanufacturad dairy products (fat basis) Poultry (fat basis) Eggs FInlshad animal faads Animal faad componants of animal origin Edlbla portion of fish and shall fish Infant and junior foods Papar food packaging natarial SOURCE: 21 CFR 109.30. Tamporary tolerancas (ppm) l.S l.S 3.0 0.3 0.2 2.0 5.0 0.2 10.0 0-3 NONS 224545 nqncarcinogekic effects Tests of the icut* lethality of PCB products In laboratory animals, with the exception of the guinea pig, suggest that, In general, PCB products have similar toxicity regardless of route of administration, species, or age of animal. The single dose oral LOso value In rats, rabbits, mice, and mink ranged from 0,5-20 g/kg bw (Grant and Phillips, 1974; Bruckner et al.. 1973; Kimbrough et al.. 1976; Flshbaln, 1974; Garthoff et al., 1981. Aulerlch and Ringer, 1977), Route of administration also had little effect (less than one order of magnitude) on lethality, with the lethal dose for dermal administra tion in rabbits ranging from 0.7-3 g/kg bw (Nelson et al., 1972), while the lethal dose In mice administered PCBs by Intraperltoneal Injection ranged from 0.8-1,2 g/kg bw (Lewln et al., 1972)* There are only two Indications of major differences In the acute toxicity of PCBs. First, there Is limited evidence that the guinea pig may be more sensitive to the lethality of PCBs than other species. Miller (1944) observed a 1001 mortality In a small group of guinea pigs receiving two oral doses of PCB (43% chlorine) at levels of 67 mg/animal at an Interval of 7 days apart; and McConnell and Kinney (1978) reported an L05Q.3O of 0.5 mg/kg for the PCB isomer 3,4,5-sym-hexachloroblphenyl (MC8) In guinea pigs. This Indication of possible large Interspecies differences In sensitivity Is of concern In specles-to-specles extrapolation when there Is Insufficient data to Indicate which experimental animal most accurately reflects the sensitivity of humans. The second problem concerns the possible large difference In toxicity of speci fic Isomers of PCBs. There are Indications, on the basis of limited data available from Blocca et al. (1981), that four different hexa-PCBs differ In LO50 value from 19 mg/kg to >64 mg/kg after oral administration to mice. It 0-4 MONS 224546 would not be unreasonable to assume that even larger differences will be en countered as more isomers are tested. Variation in toxicity of the different Isomers Is not of great concern In defining acceptable environmental levels, since Individual Isomers were not commercially made and released to the envi ronment. The analytical methods used to measure environmental PCBs determine the levels, in mg, of specific Aroclors. Since, as described above, the Aroclors do not differ greatly In acute toxicity, using data from the most toxic Aroclor should be protective without overly penalizing the other Aroclors. Some data are available on the nonlethal acute toxicity of PCBs admini stered by the oral route for periods of 30 days or less. The effects described In these studies were alterations of the liver, thyroid, and reproductive system. Rosin and Martin (1983) reported that a dose of 500 mg/kg of Aroclor 1254 fot>14 days to CO-1 mice decreased pentobarbital sleeping time. Indicating a substantial Induction of microsomal enzymes. At lower doses, Sanders et al. (1974) reported that exposure of ICR mice to diets containing 250 to 62.5 ppm of Aroclor 1254 for 14 days resulted, respectively. In hepatomegaly and eleva ted serum corticosterone (the latter presumably as a result of altered liver steroid metabolism). These exposures would result In doses of 32.8 and 8.1 mg/kg bw/day, assuming that a mouse consumes 131 of Its body weight per day. Similarly, Narbonne (1979) reported decreases In phenobarbltal sleeping time In Sprague-Oawlay rats maintained fro 8 days on a diet containing 100 ppm of Phenoclor OPS (dose of 5 mg/kg bw/day, assuming that a rat consumes 51 of Its body welght/day). PCS-Induced Increases In liver enzymes were suggested as the reason for the Increase In testicular acid phosphatase observed by Dlkshlth et al. (1975) In Sprague-Oawley rats fed Aroclor 1254 at a dose of 50 mg/kg bw/day for 7 days. Increases In 11ver-to-body weight ratio appear to be one of 0-5 MONS 224547 the sensitive indlcetors of PCB exposure. Carter and Mercer (1983) reported that 64 mg/kg bw/dly of Aroclor 12S4 caused Increased liver weight, while.Grant and Phillips (1974) observed increased liver weight at doses as low as 12.5 and 5 mg/kg bw/day In male and female Ulster rats, respectively, receiving Aroclor 1254 In the diet for 14 days. Carter (1983) observed hepatomegaly In rats in getting diets containing as little as 20 ppm Aroclor 1254 (1 mg/kg bw/day) for 14 days. Ooses as low as 1 ppm In diet of 3,4,5,3*,4*,5'-hexachloroblphenyl (345 HCB) for 28 days caused liver microabscesses and an Increased liver weight In 18-20 g 5-week-old C5781/6J mice (Blocca et al., 1981), Although adverse this study, 0.3 ppm In diet could be considered a lowest observed adverse effects were observed at concentrations as low as 0.3 ppm In diet In this study, there Is no documentation Indicating that commercial Aroclors contain 345 HcB. Hence, this study for 345 HcB cannot be used for establishing the short-term Health Advisory (HA), corresponding to an acceptable Intake (AI) level. Besides changes In the liver, other effects reported for exposure to low levels of PCBs were Increased thyroid activity In 5herman rats maintained on diets containing 250 opm of Aroclor 1254 (12.5 mg/kg bw) for 14 days; In Sprague-Dawley rats, administration of Aroclor 1254 by gavage for 21 days at a dose of 0.05 g/kg bw/day resulted In weight loss and decreased body tempera ture (Koerlves, 1979; Koartves and Alayoku, 1980). Enlarged thyroid has also been found In Otbome-Mendel rats maintained on diets containing 5 ppm of Aroclor 1254 (0.25 mg/kg bw/day) for 4 weeks (Collins and Capon, lgSOb). This exposure level also resulted In Increased liver enzymes In Holtzman rats (Garthoff et al.. 1977). The toxicity of PCBs resulting from exposures of between 30 and 90 days has been more extensively studied. Alterations In liver hlstopathology 0-6 HONS 224548 occurred it doses is low as 5 ppm in diet for 5 weeks in Holtzman rats (Kasza et ll,, 1978b), In the mouse {MNRI), a dose of Clophen A-60, as low as 0.025 mg/mouse (0.8 mg/kg bw/day. assuming a mouse weight of 0,03 kg) for 62 days, increased the estrous cycle, probably as a result of PCB-1nduced changes tn liver sterotd metabolism (Orberg and Mhlstrom, 1973). At higher dietary con. eentratlons of 167 ppm (22 mg/kg bw) for 6 weeks, Arodor 1016 and 1242 de creased the immunologic capabilities of BALB/CJ mice (Loose et el., 1979), Species other than rats and mice have been tested to a lesser extent for this duration. Rabbits exposed to diets containing 3 ppm of Aroclor 1254 (0.15 mg/kg bw/day, assuming that a rabbit consumes 4.91 of its body weight per day) for 8 weeks developed hepatomegaly and immunosuppression. In the guinea pig, Vos and van Genderen (1973) reported that diets containing 250 ppm of Clophen A-60 (7 mg/kg bw/day, assuming that a guinea pig consumes 2.81 of Its body weight per day) for 4-7 weeks was lethal, while diets containing 50 ppm of Clophen A-60 or Aroclor 1260 (1.4 mg/kg bw) for 4 to 7 weeks produced imnunosuppresslon. Allen et al. (1974) and Allen (1975) observed comedones and facial edema in rhesus monkeys ingesting diets containing 25 of ppm Aroclor (1.1 mg/kg bw, assuming that a monkey consumes 4.21 of its body weight per day) for 2 months. Studies of subchronlc and chronic exposure (1,e., 90 days) to RGBs have failed to use sufficiently low doses to define a no observed adverse effect level (NQAEl) In rats. In Sprague-Dawley rats, Allen et al. (1976) and Allen and Abrahamson (1979) reported that a 52-week exposure to diets containing 100 ppm of Aroclor 1248, 1254, or 1262 (5 mg/kg bw/day) followed by a 13-week observation period resulted in hepatomegaly and liver necrosis. At a lower exposure of 75 ppm in the diet (3.75 mg/kg bw/day) for 36 weeks, Sprague-Dawley rats developed focal necrosis (Jonsson et al.. 19B1). Elevated liver porphy- 0-7 MQNS 224549 rinc levels were detected by botn Kimbrough et at. (1972) and Zlnkl (1977) after exposure of Sherman rats for 8 months to 20 ppm of Aroclor 1254 or 1260 (1 mg/leg bw/day} and of CD rats for 20 weeks to 10 ppm of Aroclor 1254 (0.4 mg/kg bw/day). In a study employing near*l1fetlme exposure (2 years). Morgan et al, (1981) reported an Increase In mortality (33* ss compered with 81 In controls) In Fischer 344 rats at the lowest dose tested (25 ppm; 1.2S mg/kg bw/day). The subchronic studies demonstrated Increasing liver pathology over the dose ranges studied, 0.5*5 mg/kg bw/day; while In the only chronic study, the lowest dose tested (1.25 mg/kg bw/day) resulted In early deaths. In mice, dietary exposure levels to Kanechlor*300, *400 or -500 or Arochlor 1254 of between 100 and 500 ppm (13*65 mg/kg bw/day) for periods from 23 weeks to 11 months produced hepatomegaly (Ito et el., 1973; Bell, 1983; Kimbrough and Linder, 1974). Holier (1977) used groups of BALB/CJ mice which were maintained for 9 months on diets containing 0, 3.75, 37.5, or 375 ppm of the Aroclors 121, 1242, or 1254 (0.46, 4.57, or 47.75 mg/kg bw/day). The Aroclor with the lowest chlorine content (1221) produced no liver lesions, while exposure to Aroclor 1242 resulted In Increased liver weight In the h1gh*dose group. In mice ex* cosed to Aroclor 1254, Increased mortality was observed In the h1gh*dose group, mild hepatopathology was observed In the median dose group, and no liver lesions were detected In the 1ow*dose group. The no observed effect level (NOEL) In this study In mice of 0.45 mg/kg bw/day Is nearly Identical to the lowest ob* served effect level (LOEL) of 0,5 mg/kg bw/ day associated with porphyria in rats (Kimbrough et.al,, 1972; Zlnkl, 1977). The only other species tested In chronic bioassays was the monkey, and It proved to be highly sensitive to the toxic effects of RGBs. The most comon observations In monkeys exposed to Aroclor 1248 In the diet for a period of from 8 to 39 months were skin lesions, palpebral edema, and erythema (Barsottl 0-8 MONS 224550 and Allen, 1975; Allen and Barsottl, 1976; Allen et al., 1980; Becker et a!., 1979). These effects Mere observed at the lowest doses tested, ranging fro* 2.5 to 3 ppm In the diet (0.095.0.126 mg/kg bw/day). In addition, Becker et al. (1979) reported that monkeys fed diets containing 3 ppm of PCBs had gastric lesions, body weight loss, and reduced hemoglobin end leukocytes. In the monkey, doses as low as 0.1 mg/kg bw/day produced frank toxic effects; no studies have been conducted from which a NOAEl can be derived or to Indicate how close 0.1 mg/kg bw/day Is to the NOAEL for monkeys. Although PCBs have not been demonstrated to be animal teratogens following oral exposure, these compounds have been demonstrated to adversely affect reproduction. When admlnstered to pregnant Wlstar rats at a dose of 100 mg/kg bw/day on days 6 to 1$ of gestation, Vllleneuve et al. (1971) observed no adverse effects; however, using the same treetment schedule, 5pencer (1982) reported that Sprague-Oawley rats were Infertile after receiving 15 mg/kg bw/day, that animals receiving S mg/kg bw/day had reduced litter weights, and that 2.5 mg/kg bw/day was the NOEL. Rabbits had resorptions, abortions, and fetuses at similar dose levels of 12.5 mg/kg bw/day administered on days 0 to 2B of gestation; however, slightly smaller doses of 10 mg/kg bw/day were reported to be the NOEL. The Hartly guinea pig, which has been shown to have greater sensitivity to the toxicity of PCBs than most other species, had macerated fetuses after receiving 2.2 mg/day (6/5 mg/kg bw/day) of Clophen A-50 on days 10 to 60 Of gestation (Brunstroam et al., 1982). Effective doses of PCBs were lower than exposure occurred before and dur ing gestation. In a two-generation study, 5herman rats maintained on diets containing 20 ppm Aroclor 1254 (1 mg/kg bw/day) had reduced litter size, and at 100 ppm (S mg/kg bw/day) the pups that were born died during nursing (Linder et al., 1974). in this study, 5 ppm (0.25 mg/kg bw/day) was the NOEL. Complete 0-9 MOHS 224551 loss of fertility was observed In mala and female Wlstar rats caged together for 9 weeks while Ingesting 6,4 mg/kg bw/day of Aroclor 1254 omjlslfled In their drinking water (Baker et al.. 1977), Kales regained normal fertility after removal from treatment for 2 weeks. When Aroclor 1254 was administered to lactttlng Holtzman rati at 32 mg/kg bw/day on days 3, 5 and 7 of lactation, the future mating behavior of nursing male pups was adversely affected (Sager, 1983), A lower dose of 8 mg/kg bw/day was a NOEL. Of the species tested, the mink and the monkey are the most sensitive to the reproductive toxicity of PCBs. Bleavlns et al. (1960) maintained mink on diets containing 5 ppm Aroclor 1242 or 20 ppm Aroclor 1016 (doses of 0.75 and 3 mg/kg bw/day, assuming that a mink consumes 151 of Its body weight per day) for 18 months and observed complete reproductive failure In the Aroclor 1242 group and 251 mortality and Infertility In the Aroclor 1016 group. A more recent study by Aulerlch et al. (1985) tested yet lower doses fed te mink via diet. Aroclor 1254 at 2.5 ppm; 3,4,5,3',4*,5'-hexachloroblphenyl (345 KB) at 0.1 or 0.5 ppm; 2,4,5,2*,4',5'-hexachlorob1pheny1 (245 KB) at 2.5 or 5.0 ppm; or 2,3,6.2*,3',6*-hexachloroblphenyl (236 K8) at 2.5 or 5.0 ppm of diet were fed to groups of 10 standard dark mink (proven breeders). A group of 20 ani mals served as controls. All of the mink fed 0.5 ppm 345 KB died within 60 days, while those fed 0.1 ppm showed 501 mortality after 3 months. One still born kit was whelped In the Aroclor 1254 group. 24$ KB and 236 KB did not affect reproductive performance at either dose. In a limited study (B animals/group), Allen et al. (1980) maintained rhesus monkeys on diets containing 2.5 or 5 ppm (0.1 or 0.2 mg/kg bw/day) of Aroclor 1248 for 18 months. In the low-dose group. Increased abortions were observed, while In the high-dose group, the mothers showed overt signs of toxicity and no live births occurred. After removal from exposure for 1 year, 0-10 HONS 224552 fertility had still not returned to normal, and soma pups died during nursing. It Is apparent that frank effects In reproduction were observed In mink at lower doses than In monkeys and still lower than the NOEL In rats, rabbits, and guinea pigs following repeated exposure to PCBs. QUANTIFICATION OF SHORT-TERM HEALTH ADVISORY LEVELS PCBs belong to a class of chemically stable, multi-use Industrial chemicals that have been widely distributed in the ecosystem. Technical preparations con sist of complex mixtures of discrete PCB Isomers. Because of their physicochem ical properties, PCBs have been used as heat exchangers, dielectric, hydraulic and lubricating fluids, plasticizers, pesticide extenders, adhesives, printing inks and surface coatings. The physical and chemical proparties and the chtmlcal formations of PCBs vary considerably, depending on the amount and position of chlorine substitu tion. Such properties as stability, volatility, and water solubility are par ticularly Important in regard to frequency of occurrence fn the environment. The higher chlorinated biphenyls are less volatile than the lower chlorinated biphenyls (Mleure et al., 1976). PCBs are extremal/ Insoluble In water. The solubility of commercial mixtures (for example, the Aroclors) ranges from 25 to 200 ppb (25 to 200 ug/l), depending on the chlorine content (Nlsbet and Saroflm, 1972; Haque et al., 1974). The solubility of discrete PCB Isomers has been examined, and ranges from 1 to 600 ppb (1 to 600 *g/L) depending on the degree of chlorine substitution In the biphenyl ring (Haque and Schmeddlg, 1975). PCBs elicit a variety of adverse health effects. This Is true of even partially well-defined compositions such as Aroclor 1254. For example, toxl- 0-11 MOMS 224553 cology studies on Aroclor.1254 of less less than 30 days' duration report liver toxicity (Grant and Phillips, 1974; Carter, 1983), thyroid toxicity (Collins and Capen, 1980a, b, c) and reproductive toxicity (Vllleneuve et al,, 1971), as well as other types of toxicity (U,$. EPA, 1985b). At first. It would seem that this variety In elicited adverse effects would make it diffi cult to distinguish the critical toxic effects of PCBs. However, It appears that the experimental thresholds for these effects may be similar, at least for studies of 30 days1 duration or less. Vllleneuve et al. (1971) found Increased Incidences of fetal death, re sorptions, and abortions at 12.5 mg/kg/day of Aroclor 1254 In rabbits when exposed on days 1 through 28 of pregnancy. A dose of 1.0 mg/kg/day appeared to be without effect. Collins and Capen (1980a, b, c), In a series of studies on thyroid effect In rats, determined that SO ppm of diet ( 2.5 to 5.0 mg/kg/day) for 4 weeks was associated with clearly defined adverse effects, but that doses of S ppm of diet (~ 0.2S to 0.5 mg/kg/day) were not. Carter (1983) demonstrated liver hepatomegaly In rats at doses of 20 ppm Aroclor 1254 of diet (- 2 mg/kg/day) for 14 days; such an effect In the absence of toxicity (e.g., fatty Infiltration of the liver) might not be considered adverse. Grant and Phillips (1974) observed Increased liver weights at doses as low as 5 mg/ kg/day Aroclor 12S4 given In corn oil for 7 consecutive days. Collectively, these studies Indicate that the experimental threshold for adverse effects of Aroclor 1254 In studies of 30 days1 duration or less is at or near a dose of 1 mg/kg/day. Thus, It seems reasonable to use this latter dose as a basis for health risk assessments for Aroclor 1254 for short durations. Utilizing a dose of 1 mg/kg/day weight as a ho Adverse Effect dose, a 10day exposure level for PCBs may be calculated as follows: D-12 HONS 224554 10-day exposure level - 1 mg/kq/day x 10 kg - 0.1 mg/day for i IQ.kg child loo * where 10 kg > assuned body weight of a child, and 100 uncertainty (safety) factor chosen In accordance with the National Academy of Sciences guidelines. In which a NQAEL from an animal study Is employed. For a 7Q-kg adult the 10-day exposure level would be 0.7 mg/day. CARCINOGENIC EFFECTS A nuaber of short-term assays predictive of carcinogenic potential have been performed using the Aroclors and Individual Isomers of KBs. Negative results have been obtained In the reverse nutation assay using S.. typhlmerlji (Schoeny at al.., 1979; Schoeny, 1982; Haddle and Bruce, 1977), and In the dominant lethal assay In rats (Green et al., 197$). KB products also did not produce chromosomal changes In 0. melanogaster (Nilsson and Ramel, 1974) or In the sperm and bone narrow cells of rats (Green et al., 1975; Garthoff et al., 1977; Olkshlth et al., 197$). Wyndham et al. (1976), however, observed Increases In reversion frequency 1n. typhlmurlm exposed to 4-chloroblphenyl and to a lesser extent with Aroclor 1221, while the more highly chlorinated 2,2' ,5,5*-tetrachloroblphenyl and Aroclor 1254 were negative. The positive response was observed In one strain, TA1538, In the presence of a metabolic activation system derived from rabbit liver. In addition, a weak positive response was observed by Peakall et al. (1972) In an assay of chromosomal aberration In the embryos of ring doves fed Aroclor 1254. The variable data observed with KBs Is consistent with the poor response and lack of correlation 0-13 Mo"S 22*SS5 with animal carcinogenicity data reported for many highly chlorinated compound* In short-term assay. Early bioassays of KBs ware inadiquata as a result of small group size or periods of exposure extending for less than 1 year. These studies failed to demonstrate that PCBs were carcinogenic when fed to rats or mice (Klmura and Baba, 1973; Ito at al., 1973; Ito at al., 1974; Kimbrough and Linder, 1974). The study by Kimbrough and Linder (1974) in which 50 BAL8/CJ male mice were fed diets containing 300 ppm of Aroclor 1254 for 6 or 11 months was suggestive that Aroclor 1254 was a liver carcinogen. Of the 22 animals surviving PCI treatment for 11 months, all had areas of adenoflbrosls In the liver, and seven had histologlcally Identified hepatomas. In animals surviving 11 months which are maintained on PCI'contaminated diets for 6 months, and In control animals, there were, respectively, only 0/24 and 0/58 livers with areas of adenoflbrosls and 1/24 and 0/58 animals with hepatoaias. There were no histologically Identi fied hepatocellular carcinomas In any group. In a later study In rats using a larger group size and a longer exposure period, Kimbrough et al. (1975) reported an Increased Incidence In hepato cellular carcinomas In animals exposed to KBs. In this study, 200 female Sherman rats were exposed to diets containing a nominal 100 ppm (range 70-107 ppm) of Aroclor 1260 for 630 days. The Incidence of hepatocellular carcinomas In the treated group compared with control animals wes 26/184 and 1/173, respectively; while the Incidence of hepatic neoplastic nodules was 144/184 and 0/173, respectively. In the only other chronic bioassay performed (NCI, 1978), 24 male and 24 female Fischer 344 rats/group were maintained on diets containing 0, 25, 50. or 100 ppm of Aroclor 1254. Although dose-related Increases In nodular hyper plasia were observed, there was no significant Increase In neoplastic lesions. 0-14 MOMS 224956 Uitfi respect to the tumor Incidence reported by Kimbrough et el. ( 1975), the number of rets/group In the NCI study may have been too small to detect a carcinogenic response. Very limited information is available on the carcinogenicity of PCBs in humans. In a survey of 1,200 patients In Yusho, Japan, 5.5 years after expo sure to PCBs, 41% of the 22 deaths were attributed to neoplasle (Kuratsune, 1976; Urabe, 1974). The relevance of these findings Is unclear since the tumors were at various common sites, and comparable Incidences for en unexposed population were not presented. In two letters to the editor, Bahn et al. (1976, 1977) described suspected Increases In malignant melanomas In a small group of workers exposed to Aroclor 1254. In the 31 "heavily exposed" workers, there were two cases of melanoma, while In the 41 "less heavily" exposed workers, there wes one melanoma. The International Agency for Research on Cancer (IARC) estimates that only 0.04 cases would be expected In this number of Individuals (IARC, 1978). The only epidemiologic study (Davldorf and Knupp, 1979) examined the association between ocular melanomas and populations resid ing in areas of known high environmental levels of PCBs. The authors concluded that a causal relationship between PCBs and ocular melanomas was not demon strated. The IARC (1978) considered the association between exposure to Aroclor 1254 and malignant melanomas described In the two letters to the editor of the New England Journal of Medicine (Bahn et al.. 1976, 1977) to be sugges tive evidence that PCBs are human carcinogens. 9-15 *0*S 224557 QUANTIFICATION OF CARCINOGENIC RISK WEIGHT OF EVIOENCE FOR HUMAN CARCINOGENICITY The likelihood that a chemical such as PCB Is a human carcinogen Is ex* pressed through a characterization or stratification of tha "weight of evi dence" (human, animal, short-term test) and a final Indiction of the "overall weight of evidence" for human carcinogenicity. The IARC has characterized the evidence for the carcinogenicity of PCBs in humans as "Inadequate," the evidence for carcinogenicity In animals as "suffi cient," and the supportive evidence from short-term tests as "Inadequate," (IARC, 1982). The overall welght-of-evldence designation for PCBs under the IARC scheme Is 29 (probably carcinogenic In humans; evidence inadequate In humans and Sufficient In animals). The EPA has recently proposed a similar scheme, which Is an adaptation of the IARC scheme (U.S. EPA, 1984a). There are some differences In the two schemes; however, for PC8s the requirements for Inadequate evidence of carcinogenicity In humans and for sufficient evidence In animals are essentially Identical. Similarly, the overall welght-of-evldence under the new EPA scheme would be designated as 82, which has the seme require ments as the 2B designation of the IARC scheme. To comply with the EPA proposed guidelines for carcinogen risk assessment (U.S. EPA, 1984a), any final risk estimate developed or used In risk charac terization should be coupled with the EPA classification of the qualitative welght-of-evldence. Thus, those risk levels used In this paper are understood to carry the "92" designation; for example, 1 x 10~$ (82), 1 x 10~* (92), etc. POTENCY SLOPE FACTORS The use of a potency slope factor, necessary In calculating risk or backcalculating permissible PCB soil concentrations from selected risk levels, does D-16 MOMS 224558 not definitely Indicate that the chemical Is a human carcinogen. The likeli hood that the agent Is a human carcinogen ls`a function of the welght-ofevidence described above. The proposed EPA guidelines for carcinogen risk assessment (U.S. EPA, 1984a) suggest that agents falling Into Groups A and 8 are suitable for quantitative risk assessments. The U.S. EPA Carcinogen Assessment Group (CAG) has used the data from female rats in the study by Kimbrough et al. (197$) to quantify the carcino genic risk from exposure to PCBs (U.S. EPA. 1980). In this analysis, the TWA concentration of PC8 (Aroclor 1260) In the diet was determined to be 88.4 ppm. associated with a dally dose of 4.42 mg/kg bw/day, by assuming that an adult rat consumes food equal to S% of Its body weight per day. In addition, for this analysis, the Incidence of hepatocellular carcinomas (26/184 In treated animals and 1/173 In controls) and neoplastic nodules (144/184 In treated animals and 0/173 In controls) were combined to produce tumor Incidences of 170/184 and 1/173 In the treated and control groups, respectively, using these data and the linearized multistage model, a cancer potency value (q^) for human exposure to Aroclor 1260 of 4.34 (mg/kg/day)*1 was calculated using the data in Table D-2. The U.S. EPA Office of Toxic Substances (OTS) has also used the data from the same study, but by altering two of the variables (see Table 0-2), calculated a qj of 3.57 (mg/kg/day)-1 (U.S. EPA, 1985a). The average of these two values Is 4.0 (mg/kg/day)"1, and this value has been adopted by this health advisories appendix for use In developing advisory levels for PCBs clean-up. Using this qj, a risk-specific dose (RSO) of Aroclor 1260 that would result in an increased lifetime risk level of 10~$ for a 70-kg man can be calculated as follows: 0-17 MOHS 224559 TABLE 0-2. DATA USED AS THE BASIS FOR THE qj Species Strain Sea Body weight (assumed) Length of exposure Length of experiment Tumor site Tumor type PCB product tested rat Sherman female 0.4 kg (0.35 kg) 64$ days (730 days)* 730 days 11 ver combined hepatocellular carcinomas ' and neoplastic nodules Aroclor 1260 Dose (mg/kg/day) 0 4.42. Incidence (Wo, respondlnq/Wo. tested) 1/173 170/184 The dete In parentheses Indlcete the alternative values used by OTS In computing a cancer potency factor. SOURCE: Kimbrough et a1.t 1975. 0-18 MOMS 224560 RSO l x 10' x 70 kg bw t 0.175 ug/dey. (mg/kg/dey)'* Thus, using the qf for humens of 4.0 (mg/kg/dey)"1, the RSDs corresponding to lifetime risks of IQ*4, IQ*5, end IQ*6 ere 1.75, 0.175, end 0.0175 ug/dey, respectively. The edoptlon of these potency end concentretlon levels for ell PC9s requires e further essumptlon thet ell KB compounds ere cerclnogenlc end thet the potency of Aroclor 1260 Is representedve of eny mixture of eny other PCB compound. SPECIAL CONSIDERATIONS HIGH-RISK SUBPOPULATION Two seperete groups of high-risk subpopuletlons for exposure to KBs mey be Identified. The first group Includes those persons with the potentlel for frequent or high exposure, nemely, occupetlonelly-exposed workers end breestfed Infents, es PCBs ere excreted In the breest milk of lectetlng humens (Hiller, 1977; Rogen et el., 1960; Wlcklzer et el., 1981; Hes end Devles, 1979 Kuwebere et el., 1979; Hofvender et el., 1981). The second group Includes those persons with en Ineblllty to oxidize KBs vie glucuronldetlon to fecllltete detoxlfleetIon end ellmlnetlon of these toxlcents, such es embryos, fetuses, end neonetes (2 to 3 months old) (Celebrese end Sorenson, 1977; Gillette, 1967; Nyhen, 1961), especlelly breest-fed Infents who receive e steroid vie humen breest milk thet Inhibits glucuronyl trensferese ectlvlty (Celebrese end Sorenson, 1977; Gertner end Arles, 1966), children slmulteneously exposed to the entlblotlc novobiocin (Lokletz et el., 1963; Celebrese end Sorenson, 1977), persons with Gilbert's syndrome or Crlgler end NeJJer 0-19 HONS 224561 syndrome (L*t*r and Scnmld, 1964; Calabrese and Sorenson, 1977), or persons with hepatic Infections such as Infectious hepatitis (Calabrese and Sorenson, 1977), COCARCINOGENESIS, INITIATION, AND PROMOTION DIGIovannl et el. (1978) demonstrated that Aroelor 1254 had weak tumor Initiating activity In the mouse two-stage tumorlgenesis models. Promoting activity was not indicated for this Aroelor In a study by Berry et al. (1979). Using otner experimental systems, [to et al, (1973) observed an Increased Inci dence of liver tumors In rats co-aomlnlstared PCBs and benzene hexachlorlde as compared with benzene hexachlorlde treatment alone. Co-admlnlstrati on of other potent live carcinogens, 3'-methyl-4-dlmethyl ami noazobenzene. N-2-fluorenylacetemlde and dlethylnltrosamlne, with PCBs, hMever, has resulted In the Inhibi tion of the tumorlgenic response (Ito et al., 1973). Similarly, anti neoplastic effects were reported by Nlshlzuml (1980) for pups of dams administered nanechlor-500 and diethylnltrosamlne. These studies make It apparent that expo sure to KBs can affect the carcinogenicity of other xenoblotlcs. SUmARY For the purposes of setting advisory levels for PCBs cooturinating soils, acceptable Intake (Al) levels have been developed which are based on both the toxicity and the carcinogenicity of KBs. The 10-day health advisories (HA) for toxicity other than cancer have been developed. The 1-day and lifetime HAs could not be evaluated. Advisories for the cancer end point are expressed In terms of 10** to 10*7 lifetime Individual excess risk levels. See Table 0-3 for summary of these Als and risk-specific doses. 3-:o MOMS 224562 TABLE 0-3. SUMMAKY OF RISK SPECIFIC DUSES (USDs) FOR CANCErt RISKS UF PC8S. OR OF ACCEPTABLE INTAKES FOR PROTECTION AGAINST THE nONCARCInUGEnIC EFFECTS OF PCBS Description lU-4 RSO 1U-5 KSO lU" RSO Short-torn Al (l-a*y) Lonytr-ttrn Al (10-Oty) LlfttlM Al Vlluo (wB/Oty) 1.75 0.175 U.0175 Not ostlMtoa 10U for i child 7UU for on Mult Not ostlMted 0-21 HONS 224563 The toxicity and carcinogenicity of PCBs have recently been critically evaluated In a number of EPA documents (u.S. EPA, i960, 1963, 19B46, 1965b). The approach taken here In developing a 10-day exposure advisory for non cancer toxicity has been to select from the available literature the animal study that addresses the critical toxic effect and yields the most appropriate no observed effect, no observed adverse effect, lowest observed effect, or lowest observed adverse effect level. This dose was then divided by an appro priate uncertainty factor to obtain the 10-day HA. The calculation of a 10-day HA for noncarc1no9en1c toxicity should make use of animal data derived after an exposure period ranging from 10 to 30 days The literature contains several animal studies which address this length of exposure. The studies chosen as a basis for the 10-day HA (Yllleneuve et al., 1971; Grant and Phillips, 1974; Collins and Capen, 1980a, b, c; Carter, 1983) yield a Ho Observed Adverse Effect Level (NOAEL). These studies Involved the feeding of Aroclor 1254 to rabbits and rats. Collectively, In these studies, NOAEL can be ascribed to a dose of 1 mg/kg/day). Dividing this NOAEL by an uncertainty factor of 100 yields a 10-day HA of 100 ug/k9/day for a child, and 700 ug/day for a 70-kg adult. The 1-day HA could not be estimated based on animal data derived from studies with an exposure duration of 1 to 5 days. The lifetime HA noncancer toxicity, likewise, could net be estlmeted. The cancer risk specific doses (Intake levels) have been calculated by solving for exposure In the equation Risk Potency x Exposure and multiplying by 70 kg. A cancer potency factor of 4.0 (mg/kg/day)*1 was 0-22 HONS 224564 adopted for use In these calculations. This vtiue Is the mean of the vlUes determined by OTS (3.57 (m^A^/day)"*) and by ORO (4.34 (n>9A9/day)*l).for PCBs. 0-23 HONS 224565 REFERENCES (APPENDIX 0) Allen, J.R. (1975) Response of the non-human prlmete to polychlorlntteO biphenyls exposure. Fed. Proc. 34:1675-1679. Allen, J.R.; Abrahamson, L.J. (1979) Responses of rets exposed to poly chlorinated biphenyls for 5Z weeks. II. Compositions!'end enzymic changes In the liver. Arch. Environ. Contsa. Toxicol. 8:191. Allen, J.R.; Barsottl, D.A. (1976) The effects of trensplscentsl end mam mary movement of the PC8s on Infsnt rhesus monkeys. Toxicology 6:331-340. Allen, J.R.; Barsottl, O.A.; Csrstens, L.A. (1980) Reslduel effects of polycnlorlnsted biphenyls on adult nonhumsn primates and their off spring. J, Toxicol. Environ. Health 6(l):55-66. Allen, J.R.; Carsten, L.A.; Abrahsmson, L.J. (1976) Responses of rats exposed to polychlorinated biphenyls for 52 weeks. 1. Comparison of tissue levels of PCS and b1ol09lca1 changes. Arch. Environ. Contsm. Toxicol. 4:409. Allen, J.R.; Norback, D.H.; Hsu, l.C. (1974) Tissue modifications In mon keys as related to absorption, distribution, and excretion of poly chlorinated biphenyls. Arch. Ehvlron. Contsa. Toxicol. 2:86. American Conference of Governmental Industrial Hygienists (ACGItJ). (1980) Documentation of the threshold Halt values. 4th ed. (Includes sup plemental documentation, 1981). Cincinnati, OH, p. 486. Aulerlch, R.J.; Bursi an, S.J.; Breslln, W.J.; Olson, B.A.; Ringer, R.K, (1985) Toxicological manifestations of 2.4,5-2',4'.5'-, 2,3,6,2`, 3',6'-, and B^.S.B'^'.S'-hexachloroblphenyl and Aroclor 1254 In mink. J. Toxicol. Environ. Health 15:63-79. Aulerlch, R.J.; Ringer, R.K. (1977) Current status of PCS toxicity to mink, and effect on their reproduction. Arch. Environ. Contaa. Toxicol. 6:279 292. Bahn, A.K.; Grover, P.; Rosenwalke, I.; O'Leary, K.; Stallman, J. (1977) PCBs and aelanoaa. R. Gig. J. Ned. 296:108. Bahn, A.K.; Rosenwalte, I.i Herrmann, N.; Grover, P.-, Stallmen, J.; O'Leary, K. (1976) Melanoaa after exposure to PCBs. New Engl. J. Med. 295:450. Baker, F.D.; Bush, 8.; Tuaasonls, C.F.; Lo, F.C. (1977) Toxicity and per sistence of low-level PCB In adult HI star rats, fetuses, and young. Arch. Environ. Contaa. Toxicol. 5(2):143-156. Barsottl, D.A.; Allen, J.R. (1975) Effects of polychlorinated biphenyls on reproduction in the primate. Fed. Proc. 34:338. Q-24 HONS 224566 Becker, G.M.; McNulty,-W.P.; Bell, H. (1979) Polychlorinated biphenylsinduced morphologic changes in the gastric mucosa of the rhesus monkey. Lab. Invest. 40:373, Bell, m. (1983) Ultristructural features of the murine cutaneous mlcrovasculature after exposure to polychlorinated biphenyl compounds (PCBs) and benzo(a)pyrene (BAP). Virchows Arch. B. 42(2)c131-142. Berry, D.L.; Giovanni, J.D.; Juchau, M.R.; Bracken, M.M.; Gleason, G.L.; Slaga, T.J. (1978) Lack of tumor-promoting ability of-certain environ mental chemicals in a two-stage mouse skin tumorlgenesls assay. Res. Coninun, Chem. Pathol. Pharmacol. 20:101. Blocca, M,; Gupta, B.N.; Chae, 1C., McKinney, J.O.; Moore, J.A. (1981) Toxi city of selected symmetrical hexachloroblphenyl isomers In the mouse. Toxicol. Appl, Pharmacol. 58:461-474. Blaavlns, M.R.; Aulerlch, R.J.; Ringer, R.K. (1980) Polychlorinated biphe nyls (Aroclors 1016 and 1242): effects on survival and reproduction in mink and ferrets. Arch. Environ. Contain. Toxicol. 9(5):627-63$. Bruckner, J.V.; Khanna, K.L.; Cornish, H.H. (1973) Biological responses of the rat to polychlorinated biphenyls. Toxicol. Appl. Pharmacol. 24:434 448. Brunstroem, 8.; Klhlstroem, I.; Lundkvlst, U. (1982) Studies of fetal death and fetal weight In guinea pigs fad polychlorinated biphenyls (PCBs). Acta. Pharmacol. Toxicol. 50(2):100-103. Calabrese, E.J.; Sorenson, A.J. (1977) The health effects of PCBs with par ticular emphasis on human high-risk groups. Rev. Environ. Health 2(4): 285-304. Carter, J.W. (1983) Onset of hopatomtgaly In PCB (Aroclor 1254).treated rats. Bull. Environ, Contam. Toxicol. 31(2):183-187. Carter, J.W.; Mercer, L.P. (1983) Prediction of food Intake, weight gain, and organ weights In rats as a formulation of dietary Aroclor 1254 (PCBs) by the saturation kinetics model for physiological responses. Nutr. Rap. Int. 27:561-568. Collins, li.T.J Capon, C.C. (1980a) Biliary excretion of thyrolxlno-I-125 and fine structural alterations In the thyroid glands of gunn-rats fed PCBs. Lab. Invest. 43:158. Collins, W.T.; Capon, C.C. (1980b) Ultrastructural and functional altera tions of the rat thyroid gland produced by polychlorinated biphenyls compared with iodide excess and deficiency, and thyrotropin and thyrox ine administration, Virchows Arch. B, 33(3)1213-231. Collins, W.T.; Capon, C.C. (1980b) Pine structural lesions and hormonal alterations in thyroid glands of perinatal rats exposed In utero and by the milk to polychlorinated biphenyls. Am. J, Pathol. 99(ITTl25-141. 0-25 HONS 224567 Davldorf* F.H.; Knupp, J,A. (1979) Epideniology of ocular melanoma, Incidance and geographic relationship in Ohio (1967-1977). Ohio State Mod, J. 7S(9):561-S64. DlGiovannl, j.; Slaga, T.J.; Berry, O.L.; Juchan, N.R. (1978) The effects of 2.3,7,8-tetrachlorodlbenzo-p-dloxln (TCOO) and Aroclor 1254 on 7,12dimethylbenz[A]anthracene metabolism and tumor-initiating activity In mouse Skin, Proc, AACR, ASCO 19:110, Dlkshith, T.S.S,; Rockwood, W.; Abraham, R,; Coulston, F. (1975) effects of polychlorinated biphenyls (Aroclor 1254) on rat testis, Exp. Nol. Pathol. 22:376, Flshbeln, L, (1974) Toxicity of chlorinated biphenyls. Ann, Rev. Pharmacol. 14:139. Garthoff, L,H,; Cerra, F.E.; Narks, E.M, (1981) Blood chemistry alterations In rats after single and multiple gavage administration of polychlorina ted biphenyls. Toxicol. Appl. Pharmacol. 6Q(l):33-44. Garthoff, L,H.; Friedman, L.; Farbar, T,N,; Locke, K.K.; Sobotka, T.J.; Green, S,; Hurley, N.E.; Peters, E.L.; Story, 6.E.; Noreland, F.N.; Graham, C.H.; keys, J.E.; Taylor, N.J.; Seal era, J.V,; Rothieln, J,E,; Narks, E.N.; Carra, F.E.; Rodl, S.B.; Spom, E.M. (1977) Biochemical and cytogenetic affects In rats caused by short-term Ingestion of Aroclor 1254 or FI remaster BP6. J. Toxicol. Envlroo. Health 3:769-796. Gartner, L.N.; Arias, I.N. (1966) Studies of prolonged neonatal jaundice In the breast-fed Infant. J. Pedlat. 68(1):54. Gillette, J.R. (1967) Individually different responses to drugs according to age, sex, and functional or pathological state. In: Wolstenholme, G.; Porter, R., eds. Drug responses to man. Churchill, London, p. 28. Grant. D.L.: bhllllos. H.E.J. (1974) The effect of age and sex on the toxi city of Aroclor 1254, a polychlorinated biphenyl. In the rat. Bull. Environ. Contarn. Toxicol, 12:145-152. Green, S.; $auro. F.N.; Friedman, L. (1975) Lack of dominant lethality In rats treated with polychlorinated biphenyls (Aroclors 1242 and 1254). Food Cosmet. Toxicol. 13:507-510. Haque, R.; Schmeddlng, O.V.; Freed, V.H. (1974) Aqueous solubility, adsorp tion and vapor behavior of'polychlorinated biphenyl Aroclor 1254. Environ. Scl. Technol. 8(2):139-142. Haque, R.; Schmeddlng, O.M. (1975) A method of measuring the mater solubility of hydrophobic chemicals: solubility of five polychlorinated biphenyls. Bull. Environ. Contan. and Toxicol. 14(1):13-lS. 0-26 HOMS 226568 Hefldlt. J.A.; Bruce, W.R. {1977} Comparison of tests for mutagenlcity or carcinogenicity using assays for sperm abnormalities, formation of mlcronucl'el, and mutations In Salmonella. In: Hiatt, H.H., ed. Origins of human cancer: proceedings of conference on cell proliferation. Cold Spring Harbor, NY. Vol. 4, p. 1549. Hofvander, r.; Hagman, U.; Linder, C.E.: Vat, R.; SI orach, $,A. (1981) World Health Organization collaborative breast feeding study. 1. Organochlorlne contaminants in individual samples of Swedish human milk, 1978*1979. Acta. Paedlatr. Scand. 70(1):3-8. International Agency for Research on Cancer (IARC). (1978) Polychlorinated biphenyls. 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