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AR226-2548 RCRA FACILITY INVESTIGATION REPORT DUPONT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA JUNE 30,1999 Project No. OD6W7205 Prepared by ^ CORPORATE REMEDIATION GROUP An Alliance between DuPont and The W-C Diamond Group Barley Mill Plaza, Building 27 Witmington, Delaware 19880-0027 EID090342 jn|ihi,lil.l4,^iiblilil.i<,iililililiti|i|iMillllft|i|iMlM^!ttBili|il<>ilillHljJ)iffijji SSSSSSSS^!^- RCRA FACILITY INVESTIGATION REPORT DUPONT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA JUNE 30,1999 nMMuiiiuii ^frZOOOHSV APPROXIMATE AERIAL EXTENT OF- SOLID V MANAGEMENT UNIT C-6 APPROXIMATE AERIAL EXTENT OF SOLID V| MANAGEMENT UNIT H-14 "; APPROXIMATE AERIAL EXTENT OF SOLID V' -: MANAGEMENT UNIT A-3 r:! APPROXMATE AERIAL EXTENT OF SOLID Vl :: MANAGEMENT UNIT B-4 PERMITTEB HAZARDOUS WASTE FACILITY TITI& RFI SOIL SAMPLING DuPONT WASHINGS WASHINGTON. WES'i . >* t."''' o 300 600 FEET Fl DHE CHKD: APPD: nG DATE: 05/24/99 REV.: 0 EID090345 DuPoni WashinglonWorks P.O. Box 1217 Parkersburg.WV26)02-1217 CERTIFIED MAIL RETURN RECEIPT REQUESTED Mr. Martin Kotsch Project Manager U.S. EPA, Region ffl 1650 Arch Street Philadelphia, PA 19103-2029 June 24,1999 RE: Permit WVD045875291 Dear Mr. Kotsch: Please find enclosed the RCRA Facility Investigation (RFI) Report of Findings for your review and comment. If you have any questions or comments, please contact me at (304) 863-4271. Very truly yours, /c^^S^ R. L. Ritchey Sr. Environmental Control Consultant Washington Works Attachment CC: Mr.MarkPriddy Office of Waste Management WV-DEP 1356 Hansford Street Charleston, WV 25301 Ms. Barbara Taylor, ChiefOffice of Water Resources WV-DEP 1201 Greenbrier Street Charleston, WV 25311 Mr. B. F. Smith, ChiefOffice of Waste Management Charleston. WV 25301 1356 Hansford Street * cover letter only .: -.--..,- -,..,.. Q...... EID090346 RCRA FACILITY INVESTIGATION REPORT DUPONT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA USEPA PERMIT NUMBER WVD04-5 87-5291 June 30,1999 ^ CORPORATE REMEDIAT10N GROUP An Alliance botwwn DuPontand The W-C Diamond Group Bariey Mill Plaza. Building 27 WImington, Delaware 198804027 /Mu^yi^ rAc 'f^jiA^ j^ Elizabeth Bishop7/ W-C Diamond Project Manager Project No. OD6W7205 DuPont CRG Project Director W-C Diamond Deputy Project Manager EID090347 Executive Summary...............................................................................................................................ES-1 Section 1 1-1 Introduction.................................................................................................................... Section 2 1.1 SWMU Descriptions................................................................................ 1-1 1.2 RFI Purpose and Investigation Tasks...................................................... 1-2 1.3 Guidance Documents............................................................................... 1-2 Facility Description........................................................................................................ 2-1 Section 3 2.1 Topographic Setting................................................................................. 2-2 2.2 Regional Geologic Setting....................................................................... 2-2 2.3 Regional Hydrogeology........................................................................... 2-2 2.4 Regional Groundwater and Surface Water Use....................................... 2-3 2.5 Local Geology and Hydrogeology........................................................... 2-3 2.5.1 2.5.2 Groundwater Flow Directions...................................................... 2-4 Transmissivity, Hydraulic Conductivity, and Groundwater Flow Velocity............................................................................... 2-5 2.6 Surface Water........................................................................................... 2-5 2.7 Known Releases From Site SWMUs....................................................... 2-6 RCRA FacilityField Investigation................................................................................. 3-1 3.1 Soil Sampling Methods............................................................................ 3-1 3.2 Site-Wide Monitoring Well Installations................................................. 3-2 3.2.1 Monitoring Well Construction..................................................... 3-3 3.2.2 Monitoring Well Development.................................................... 3-4 3.3 Site-Wide Groundwater Sampling........................................................... 3-4 3.4 SWMU-Specific Sampling...................................................................... 3-5 3.4.1 SWMU A-3--Riverbank Landfill (RBL) and 3.5 3.6 3.7. 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.4.2 SWMU B-4--Anaerobic Digestion Ponds (ADP)...................... 3-5 SWMU C-o--Polyacetal Waste Incinerator (PWI)................T.. 3-6 3.4.3 SWMU H-14--Burning Ground (BG)........................................ 3-6 Background Soil Sampling...................................................................... 3-6 Soil Geotechnical Analysis...................................................................... 3-7 Slug Testing............................................................................................. 3-7 Revised Nomenclature............................................................................. 3-8 Surveying................................................................................................. 3-8 Waste Management.................................................................................. 3-8 Decontamination...................................................................................... 3-9 -' ' Quality Assurance/Quality Control........................................................ 3-10 Sample Preservation...............................................................................3-11 Field Custody Procedures...................................................................... 3-11 > ^ g -----_-------------------------------------------------------------------------------------------------------------------------------------------- M . CCNIPOHATCRCUeOIATtON GROUP Q AtA--NMM----l alPwinasnww-cauaaiHUinw BtoflUtaU.UUb HM^WWW I--MW ^S. SN-J\ . <^\ C:WlARYV205\720SRF).DOCU&JUN-9a720a 1 t<) EID090348 TABLEOFCONTENTS Section 4 RCRA Field Investigation Results............................................................................... 4-1 Section 5 4.1 Data Quality Review................................................................................ 4-1 4.1.1 RFI Data Quality Objectives........................................................ 4-2 4.1.2 RFI Analytical.Protocol Deviations...........--............................... 4-2 4.1.3 RFI Data Usability Review and Data Validation......................... 4-3 4.2 Soil Investigation .................................,,......................................--......... 4-4 4.2.1 Background Soil Sampling.......................................................... 4-4 4.2.2 SWMUA-3--^Riverbank Landfill (RBL) and SWMUB- 4.2.3 4--Anaerobic Digestion Ponds.................................................... 4-5 SWMU C-6 -- Polyacetal Waste Incinerator (PWI)................... 4-6 4.2.4 SWMU H-14 -- Burning Ground (BG)...................................... 4-6 4.2.5 Soil Investigation Summary......................................................... 4-6 4.3 Groundwater Investigation....................................................................... 4-7 4.3.1 4.3.2 Plantwide Groundwater Sampling.............................................. 4-7 Groundwater Investigation Summary.......................................... 4-8 Washington Works Groundwater Model...................................................................... 5-1 Section 6 5.1 Introduction.............................................................................................. 5-1 5.2 Conceptual Hydrogeologic Model........................................................... 5-1 5.3 Groundwater Flow Model Development................................................ 5-2 5.4 Model Calibration.................................................................................... 5-3 5.5 Sensitivity Analysis................................................................................ 5-4 5.6 Conclusion of Groundwater Modeling.................................................... 5-5 5.7 Model Limitations....................................................................................5-5 Screening Level Risk Evaluation............................................................................... 6-1 6.1 Objectives and Approach......................................................................... 6-1 6.2 Site Description and Land Use................................................................ 6-2 6.2.1 On-Site and Adjacent Land Use .............................................3-.... 6-2 6.2.2 Groundwater Uses........................................................................ 6-2 6.2.3 Surface Water............................................................................... 6-3 6.2.4 Ecological Setting........................................................................ 6-3 6.3 Data and Media Evaluated....................................................................... 6-4 6.4 Screening-Level Health Risk Evaluation................................................. 6-4 6.4.1 6.4.2 6.4.3 Potential Human Receptors.......................................................... 6-4 Screening Levels Used In the Evaluation.................................... 6-5 Derivation of Preliminary Screening Levels for FC-143............. 6-6 6.4.4 Results of Risk-Based Screening for Soil.................................... 6-7 6.4.5 Risk Screening for Production Well Water................................. 6-7 6.5 Summary of Constituents and Pathways of Concern (Human Health)..........................>...........................................................-..............6-8 <ssss ^ CORPORATE REMCOATfON WWW AlAlteDRMMMI Out'wtwsnwWCOtlimsawf C;'MARYW205\7205RF1.00029-JUN.99l720S\ II EID090349 [AAiAcl&Lfa-t-c, , Ck^t^4^ ^'rll( OAen^ EID090350 TABLEOFCONTENTS Section? 6.6 Ecological Exposure Evaluation......................................................... .....6-8 6.6.1 Exposure Areas and Media ..................................................... ,..,,6-8 6.6.2 Habitat Characterization at the RBL/ADP.............................. , ,6-9 6.6.3 Identification of Significant Ecological Resources................. .....6-9 6.6.4 Ecological Exposure Pathway Evaluation .............................. ...6-10 6.7 Summary and Conclusions................................................................. 6-10 Conclusions/Recommendations.................................................................................... 7.1 7.1 Conclusions......................................................................................... .....7-1 7.2 USEPA Environmental Indicators ...................................................... .....7-2 7.2.1 CA 725-Human Exposure Under Control............................... .....7-2 7.2.2 CA 750-Contaminated Groundwater Migration Under Control.................................................................................... 7-7 7.3 Recommendations...................................................--......................... 7-2 Sections References.................................................................................................................,,..,,8.1 FIGURES Figure 1.1 SWMU Location Map Figure 2.1 Site Location Map Figure 2.2 Nearby Industrial Land Use Figure 2.3 Regional Stratigraphic Column Figure 2.4 DuPont Production Well Fields Figure 2.5 Cross Section Location Map Figure 2.5A Cross Section A-A" Figure 2.5B Cross Section B-B' - Figure 2.5C Cross Section C-C' Figure 2.5D Cross Section D-D' Figure 2.5E Figure 2.5F Cross Section E-E' Cross Section F-F' Figure 2.6 Figure 2.7 Schematic Diagram of Riverbank Slumping of Floodplain Deposits Groundwater Round 1 Contours Figure 2.8 Groundwater Round 2 Contours Figure 3.1 RFI Sample Locations Figure 3.2 Groundwater Round I and 2 Sample Locations Figure 4.1 Methylene Chloride Results in Soil ^ CORTOflATfi HWeOKnCM flfl (MWMtf nwW-CawMl^a uHf Ml nu.. fcAlkg 3] VMWW.MWIW (MW4 C:WARY\720a7Z05RFI.DOCV29JUN-99>720a III EID090351 TflBIEBFCflMTENTS____________________ Figure 4.2 Figure 4.3 Figure 4.4 Figure 4.5 Figure 4.6 Figure 4.7 Figure 4.8 Figure 4.9 Figure 4.10 Figure 4.11 Figure 4.12 Figure 4.13 Figure 4.14 Figure 4.15 Figure 4.16 Figure 4.17 Figure 4.18 Figure 4.19 Figure 4.20 Figure 5.1 Figure 5.2 Figure 5.3 Figure 5.4 Figure 5.5 Figure 5.6 Figure 5,7 Figure 5.8 Figure 5.9 Figure 6.1 ' Figure 6.2 Freon-113 Results in Soil Tetrachloroethene Results in Soil--West Riverbank Landfill Tetrachloroethene Results in Soil--East Riverbank Landfill Trichloroethene Results in Soil--West Riverbank Landfill Trichloroethene Results in Soil--East Riverbank Landfill PC-143 Results in Soil (563 to 584 MSL Samples) FC-143 Results in Soil (585 to 605 MSL Samples) FC-143 Results in Soil (607 to 640 MSL Samples) Carbon Tetrachloride Results in Soil Groundwater Round 1 Carbon Tetrachloride Results Groundwater Round 2 Carbon Tetrachloride Results Groundwater Round 1 Tetrachloroethene Results Groundwater Round 2 Tetrachloroethene Results Groundwater Round 1 Trichloroethene Results Groundwater Round 2 Trichloroethene Results Groundwater Round 1 Freon-113 Results Groundwater Round 2 Freon-113 Results Groundwater Round 1 FC-143 Results Groundwater Round 2 FC-143 Results Model Domain Model Grid ; Model Boundary Conditions .*-. Model Conductivity Zones Calibrated Model Groundwater Potentiometric Surface with Residuals Calibrated Groundwater Model Scatter Plot of Target Heads vs. Model Heads Sensitivity Analyses Scatter Plot of Target Heads vs. Model Heads Model Verification Predicted Groundwater Potentiometric Surface with Reduced Pumping Human Exposure Pathway Evaluation Ecological Exposure Pathway Evaluation <aro ^ RAT8 RKUEOIATKUI OfKXJf M jflrf m HfC ObmMj Oiw^ iBtayiMnu.BjMiar C:WARy\7205l7205W1.0002a^lUN-97205> IV EID090352 TABLEOFCONTENTS TABLES Table 3.1 Table 3.2 Table 3.3 Table 3.4 Table 3.5 Table 3.6 Table 4.1 Table 4.2 Table 4.3 Table 4.4 Table 4.5 Table 4.6 Table 5.1 Table 5.2 Table 6.1 Table 6.2 Table 6.3 Table 6.4 Table 6.5 Table 6.6 Table 6.7 Table 6.8 Table 6.9 Table 6.10 Boring and Sample Locations by SWMU Analytical Parameters by SWMU New Monitoring Well Construction Information Monitoring Well Development Information Depth to Water Measurements for Round 1 Depth to Water Measurements for Round 2 Analytical Parameters and Result Ranges by SWMU Carbon Tetrachloride Results for Groundwater Sampling Tetrachloroethene Results for Groundwater Sampling Trichloroethene Results for Groundwater Sampling Freon-113 Results for Groundwater Sampling FC-143 Results for Groundwater Sampling Calibrated Model CALSTATS Statistics Sensitivity Analyses CALSTATS Statistics BG Soil Analytical Results 0-2 Feet BG Soil Analytical Results 2-20 Feet RBL/ADP Soil Analytical Results 0-2 Feet RBL/ADP Soil Analytical Results 2-20 Feet Production Well Groundwater Concentrations; FC-143 Screening Levels Summary of Risk-Based Screening for Soil Summary of Health-Based Screening for Production Well Water Rare, Threatened and Endangered Species Summary of Risk Evaluation Results ^ COWOIUnilEMeOaTlOKBROur BiAri--tf nr W6 OMiiMjanw C:>MARW20Sl7205RFI.D002S-JUN-97205l V EID090353 TABLEOFCONTENTS APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Soil-Sample Results versus Industrial RBCs Groundwater Round 1 Sample Results versus MCLs Groundwater Round 2 Sample Results versus MCLs Groundwater Round 3 Sample Results versus MCLs Boring Logs Monitoring Well Construction Diagrams ATTACHMENTS Attachment 1 Land Use Report ^ CORPMAIC RWEDWWH W03P O^Mf MJ ! W IXMmnrf Omy SWvWfW.flMva CAMARYV205\7Z05RFl.D0029-JUN-9fll7205t VI EID090354 RCRA FACILITY INVESTIGATION REPORT ACRONYM LIST ADP= ADQM= AEL= ASTM= BG= BGS= CED= CEG= CLP= COC= CRG= CSR= CT58 DOT= DQO= DTW= ECDs ESI= FC-143= FID= ft/sec= GC= GE= gpd/ft2" gpm= HQ= HSWA= LLI= MCL= MeCI= mg/kg= MS= Anaerobic Digestion Ponds Analytical Data Quality Management Allowable Exposure Level American Society for Testing and Materials Burning Ground Below Ground Surface Corporate Environmental Database Community Exposure Guideline Contract Laboratory Program Chain of Custody Corporate Remediation Group Code of State Regulations Carbon Tetrachloride Department of Transportation Data Quality Objectives Depth to Water Electronic Capture Detector Environmental Standards, Inc. Ammonium Perfluorooctanoate Flame lonization Detector Feet Per Second Gas Chromatograph General Electric Plastics Gallons Per Day Per Square Foot Gallons Per Minute Hazard Quotient Hazardous and Solid Waste Amendments Lancaster Laboratories, Inc. Maximum Contaminant Levels Methylene Chloride Seep Milligrams Per Kilogram Matrix Spike MSD= MSL= ND= PCE= PEF3 PID= PPE= PSD= PVC= PWI= QA= QAPP= QC= RBC= RBL= RBLL1= RCRAs RFI= RTE= SCM= SL= SOP= SWMU= TCE= TCLP= ug/kgs ug/L= USEPA= USGS= Vl= VOC= Matrix Spike Duplicate Mean Sea Level Non-Defect Tetrachloroethene Particulate Emission Factor Photo lonization Detector Personal Protective Equipment Public Service District Polyvinyl Chloride Polyacetal Waste Incinerator Quality Assurance Quality Assurance Project Plan Quality Control Risk-Based Concentrations River-Bank Landfill Methylene Chloride Seep Resource Conservation and Recovery Act RCRA Facility Investigation Rare, Threatened or Endangered Site Conceptual Model Screening Levels Standard Operating Procedure Solid Waste Management Unit Trichloroethene Toxicfty Characteristic Leaching Procedure Micrograms Per Kilogram Micrograms Per Liter U.S. Environmental Protection Agency United States Geological Survey Verification Investigation Volatile Organic Compound > M <-h VO EID090355 Executive Summan A Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) was conducted in the fall of 1998 on four Solid Waste Management Units (SWMUs) at the DuPont Washington Works to satisfy requirements of its RCRA Hazardous and Solid Waste Amendments (HSWA) Permit Number WVD 04-587-2591. The primary objectives of this investigation were to determine the nature and extent of waste constituent releases from these units into underlying soil, determine the rate of migration in groundwater and other media, and evaluate any potential impacts to human health or the environment from these releases. The four SWMUs investigated were SWMU A-3 Riverbank Landfill (RBL), SWMU B-4 Anaerobic Digestion Ponds (ADP), SWMU C-6 Polyacetal Waste Incinerator, and SWMU H-14 Burning Ground (BG). The RFI was designed to fill data gaps remaining after completion of the 1992 Verification Investigation (VI), which determined that each of these units had potentially released waste constituents into underlying soil and groundwater. The RPI scope of work included a major field effort entailing soil boring and monitoring well installation, soil and groundwater quality sampling, and field reconnaissance to identify potential human and ecological receptors. The RFI effort also included construction of a site-wide groundwater flow model to evaluate the impact of production well pumping on waste constituent migration from SWMU areas. The modeling was conducted to confirm that ongoing production well pumping prevented off-site migration ofSWMU-impacted groundwater. Soil and groundwater analytical results were compared to USEPA Region m Risk-Based Concentrations (RBCs) for industrial soil, or to Maximum Contaminant Levels (MCLs) or RBCs for drinking water. These results were evaluated in conjunction with the receptor identification results to determine if any significant exposure issues exist. The key conclusions of the RFI are summarized as follows: Q The Riverbank Landfill (RBL) and Anaerobic Digestion Pond (ADP) SWMUs have released organic constituents to underlying soils. These impacts tend to occur below land surface, are limited in areal extent, and do not exceed USEPA Region in industrial soil RBCs. a Several RBL/ADP-derived organic constituents were detected in site aquifer groundwater quality samples. However, in most instances, these constituents are at concentrations below the MCL or RBC for tapwater. This groundwater migrates to and is contained by on-site production wells. Q Two organic constituents, trichloroethene (TCE) and ammonium perfluoro-octanoate (i.e., FC-143), are present in production well groundwater, the former at concentrations exceeding its MCL, the latter at concentrations exceeding its calculated health-based screening level. This impacted groundwater does not present a human exposure risk as it is primarily used for non-contact industrial purposes. Q Ongoing production well pumping, as confirmed by the groundwater flow model, prevents off-site migration ofSWMU-derived waste constituents. Although not planned, S8S6 ^ MWMM WMMWH WWP Olfmrmtf TA we OtaMwrfOmtl Mil' in--ruin HUHiwM.DriM-- iMMOr CflMARW20S721)5RF1.00029-.IUN-9a721)a ES-1 EID090356 Biecullve Summary this pumping could be reduced by as much as 65% while still maintaining site groundwater capture. Q No significant exposure pathways to SWMU-impacted soils or groundwater exist, because all soils are covered and rendered inaccessible by buildings, asphalt, or dense vegetation; and the site aquifer groundwater is either below health-based screening levels or is primarily utilized for non-contact industrial purposes. 0 The active containment/treatment system for the methylene chloride seep (RBLL1), as constructed, effectively contains seepage and prevents off-site migration. The system is an effective final remedy. Based on these conclusions, DuPont Washington Works believes that it meets applicable criteria under USEPA's Environmental Indicator program, specifically, CA-725 Human Exposures Under Control, and CA-750 Contaminated Groundwater Migration Under Control. DuPont recommends the following current and future activities at Washington Works pursuant to its HSWA Permit/Corrective Action Program: Q Continue operation of the methylene chloride seep (RBLL1) collection/treatment system. Q Maintain production well pumping at or above 35% of present levels. Q Conduct long-term site aquifer potentiometric surface monitoring to continue to verify site groundwater capture. Q Conduct long-term groundwater quality monitoring to continue to ensure protection of human health and the environment. aaao ^ CORPOIUTE nacouncN OKXJP AlJUfMCwMW* aAntjntf nr w CliMMWOmy inirMRuMftii' C:tMARW20a7205RFI.OOCU9.JUN-9M72aa ES-2 fcQ 0 0 M 0\ EID090357 SECTIOHONE___________________IntraimeUon In response to the United States Environmental Protection Agency (USEPA) letter of May 5,1997, and in accordance with the Corrective Action portion of the Resource Conservation and Recovery Act (RCRA) Permit Number WVD 04-587-5291, DuPont Washington Works herein presents its RCRA Facility Investigation (RFI) findings for the following four Solid Waste Management Units (SWMUs): 0 SWMUA-3--Riverbank Landfill (RBL) 0 SWMUB-4--Anaerobic Digestion Ponds (ADP) 0 SWMUC-6--Polyacetal Waste Incinerator (PWT) Q SWMU H-14-^Buming Ground (BG) 1.1 SWMU DESCRIPTIONS A brief description of each of the SWMUs is presented below. SWMU locations are shown on Figure 1.1. Q SWMU A-3, Riverbank Landfill (RBL): The RBL is about 4,500 feet long and lies along the northern edge of the site near the Ohio River. It was operated between 1948 and the late 1960s and received powerhouse ash, incineration ash, plastics, rubble, and plant trash. After closure, it was covered with 6 to 35 inches of soil. Currently, the RBL is covered with dense vegetation (on its slope) or by buildings and pavement in the manufacturing area. Q SWMU B-4, Anaerobic Digestion Ponds (ADPs): Three former ADPs are co-located with a portion of the RBL. One pond dates from the 1950s and two others from the 1970s. The ponds received waste from the fluorocarbon manufacturing process until 1988, when the pond contents and upper few feet of clay liner and pond berm material were removed and disposed of off site. The pond area was backfilled and capped with topsoil, and the area is currently vegetated with grass. ~-i- Q SWMU C-6, Polyacetal Waste Incinerator (PWI): The former PWI consisted of two brick-lined pits in the western portion of the manufacturing area. The PWI operated between 1959 and 1990. The PWI has been excavated and backfilled with clean soil. Q SWMU H-14, Burning Ground (BG): The BG is located in the central portion of the manufacturing area and was operated between 1948 and 1965. Since 1990, the site has been leveled with clean fill and gravel and overlain by buildings and asphalt. A previous Verification Investigation (VI) found evidence of releases of organic constituents and possibly metals to soil and groundwater at the RBL, ADP, and BG (DuPont 1992). Little evidence of contamination was found in soil at the site of me former PWI. Further investigations and evaluations were performed for this RFI, and are reported herein. <sss ^ CQ1K1RATS IWMOWOOH WV3W AtMUHwMww PuttMI Mtf 7ft Hl OMMMtf OMIW C:WARYV20W205RnDOC\29-JUN-99\720a 1-1 > 03 0 S3 5 EID090358 SEGTIONONE Iniroduction 1.2 RFI PURPOSE AND INVESTIGATION TASKS This RFI Report was prepared in accordance with the RCRA Facility Investigation Plan that was submitted to USEEAJn 1997 (DuPont 1997). The purpose of the RFI Report is to: Q Summarize the nature and extent of releases of SWMU-related constituents and, if applicable, rate of migration. Q Provide a detailed geologic and hydrogeologic characterization of the area surrounding and underlying the SWMUs. Q Identify if potential releases are a concern for human health or the environment. Q Determine if further actions are warranted for the SWMUs. The RFI tasks that were performed to meet these objectives include: Q Background soil sampling. Q SWMU-specific soil and groundwater sampling. Q Site-wide monitoring well installation and groundwater sampling, and closure of old monitoring wells determined by site-wide survey. Q Data evaluation and identification of sources of release and nature and extent of contamination. Q Hydrogeologic characterization and groundwater flow model development and calibration. Q Identification of potential receptors and a screening-level risk evaluation to assess whether releases from SWMUs pose a threat to human health or the environment 1.3 GUIDANCE DOCUMENTS The following documents were used in the preparation of this RFI. RCRA Groundwater Monitoring: Draft Technical Guidance (USEPA Office of Solid Waste, November 1992); Test Methods for Evaluating Solid Waste Physical/Chemical Methods (USEPA, SW-846 Third Edition November 1986) RCRA Facility Investigation Guidance (USEPA 530/SW-89-031, May 1989); Selecting Exposure Routes and Contaminants of Concern by Risk-Based Screening (USEPA Region in, 1993), and other guidance documents as cited in the report. ^ ^jinweaws^awf CaMARW20Si7205WI.DOCT29.JUN-97ZOa 1-2 EID090359 SEenOMTWO_________________Facility Pescnpmm The 1,200-acre DuPont Washington Works site (also referred to as the plant or the Site) is located on the Ohio River in Washington, West Virginia, approximately seven miles southwest ofParkersburg, West Virginia (see Figure 2.1). Previously, the land was used for agriculture. The initial manufacturing units constructed at Washington Works were completed in 1948. The plant currently has 14 operating and service divisions that span nearly a mile along the Ohio River. Products manufactured at the site include: Q Compounded engineering plastics Q Nylon molding pellets and filaments Q Acrylic molding compounds Q Polyvinyl butyral Q Acrylic resins Q Fluoropolymers Q Polyacetal products Washington Works is located in an area of industrial and other land uses. Immediately adjacent to the western boundary of the plant site is the General Electric Plastics plant (GE) and two industrial warehouses (see Figure 2.2). The north side of the plant is bounded by the Ohio River, which flows west and is located hydraulically upgradient from the plant. A heavily wooded and hilly 250-acre closed solid waste landfill (i.e.. Local Landfill), owned by Washington Works, is located contiguous to and immediately south of the site. The east side of the site is bound by a small stream and steep, wooded hills. Residential areas are located within one mile on the south, east, and west sides. Other large manufacturing industries in the surrounding area include Amoco, Shell Chemicals, and Huntsman Chemicals, all being on the Ohio side of the Ohio River. Washington Works also encompasses Blennerhassett Island, located in the Ohio River, upstream of the plant (Figure 2.1). One of several Washington Works groundwater well fields is located on the island. 'SSSSI ^ coflpoMuc neucgunoN wow JtoJWWMWW OupMtun nH(caMiwaww s C:\MARW20Sl720SRF1.00029-JUN-99720a 2-1 fr EID090360 SEGTIONTWO FaclEftvDescription 2.1 TOPOGRAPHIC SETTING The Washington Works plant rests on Quaternary alluvial terrace deposits in western West Virginia's Ohio-River Valley. The alluvial terrace is topographically flat and lies approximately 50 feet above the Ohio River, which flows east to west past the site (see Figure 2.1). The alluvial terrace is underlain by a flat, river-scoured bedrock surface of the Dunkard Series that rises steeply and outcrops off the southern edge of the site to form the valley wall. The valley wall rises from an elevation of 630 feet above mean sea level (MSL) near the southern edge of the site to 860 feet above MSL at the Local Landfill (see Figure 2.2). This higher knob country south of the site is characterized by branching V-shaped valleys typical of a dissected plateau geomorphology. 2.2 REGIONAL GEOLOGIC SETTING The Washington Works plant lies on (he western edge of me Appalachian Geosynclinal basin. Valley fill Quaternary alluvium and Permian-age Dunkard Series bedrock highlands dominate the regional geologic setting. The Quaternary alluvium ranges from one to 100 feet in depth and consists ofunconsolidated river deposits of poorly to well-sorted, brown and gray sand, silts, clay and gravel. The Dunkard Series bedrock consists primarily of red and varicolored sandy shale;gray, green and brown sandstone; and minor beds of coal, claystone, black carbonaceous shale, and limestone (see Figure 2.3). 2.3 REGIONAL HYDROGEOLOGY The Quaternary alluvial terrace unconfined aquifer (i.e., alluvial aquifer) is the principal regional aquifer and is used locally for industrial, municipal, and rural water supplies. Wells in the region generally yield several hundred gallons per minute (gpm). Radial collector wells in me Ohio River yielding as much as 3,500 gpm have been reported (Schultz 1984). Natural recharge to the alluvial aquifer comes from various sources, including: Q Infiltration of precipitation falling directly on the alluvium Q Lateral movement of the river water through the alluvium via permeable sands andjgravel zones Q Seepage from streams tributary to the Ohio River The maximum amount of water available to the alluvium depends on the degree of hydraulic connection to the river. The degree of hydraulic connection is a function of the condition of the river bottom, permeability and thickness of the alluvium, and distance and hydraulic gradient between the wells and river. Pumping ofon-site active well fields near and parallel to the river (i.e., the Ranney Well, the DuPont-Lubeck Well Field and the East Well Field shown in Figure 2.4) lowers the groundwater level to below river stage. This induces water from the river to flow into the alluvium toward the wells, which replaces water pumped from storage in the aquifer, and helps sustain high-yield pumping wells. <9BB> ^ COAPOIUTE REMEdunoff WWP wwtu^ n. wrttiiiuitniiHf tay m nu4 !* zr 7-7 I> C;WAR'rt7205l7205RFI.OOCUJUN-9720a -- - ya a S OS m EID090361 SECTIOMTWO______ fading neserlptian 2.1 TOPOGRAPHIC SETTING The Washington Works plant rests on Quaternary alluvial terrace deposits in western West Virginia's Ohin River Valley. The alluvial terrace is topographically Hat and lies approximately 50 feet above the Ohio River, which flows east to west past the site (see Figure 2.1). The alluvial terrace is underlain by a flat, river-scoured bedrock surface of the Dunkard Series that rises steeply and outcrops off the southern edge of the site to form the valley wall. The valley wall rises from an elevation of 630 feet above mean sea level (MSL) near the southern edge of the site to 860 feet above MSL at the Local Landfill (see Figure 2.2). This higher knob country south of the site is characterized by branching V-shaped valleys typical of a dissected plateau geomorphology. 2.2 REGIONAL GEOLOGIC SETTING The Washington Works plant lies on the western edge of the Appalachian Geosynclinal basin. Valley fill Quaternary alluvium and Permian-age Dunkard Series bedrock highlands dominate the regional geologic setting. The Quaternary alluvium ranges from one to 100 feet in depth and consists ofunconsolidated river deposits of poorly to well-sorted, brown and gray sand, silts, clay and gravel. The Dunkard Series bedrock consists primarily of red and varicolored sandy shale; gray, green and brown sandstone; and minor beds of coal, claystone, black carbonaceous shale, and limestone (see Figure 2.3). 2.3 REGIONAL HYDROGEOLOGY The Quaternary alluvial terrace unconfined aquifer (i.e., alluvial aquifer) is the principal regional aquifer and is used locally for industrial, municipal, and rural water supplies. Wells in the region generally yield several hundred gallons per minute (gpm). Radial collector wells in the Ohio River yielding as much as 3,500 gpm have been reported (Schultz 1984). Natural recharge to the alluvial aquifer comes from various sources, including: Q Infiltration of precipitation falling directly on the alluvium Q Lateral movement of the river water through the alluvium via permeable sands and^gravel zones Q Seepage from streams tributary to the Ohio River The maximum amount of water available to the alluvium depends on the degree of hydraulic connection to the river. The degree of hydraulic connection is a function of the condition of the river bottom, permeability and thickness of the alluvium, and distance and hydraulic gradient between the wells and river. Pumping ofon-site active well fields near and parallel to the river (i.e., the Ranney Well, the DuPont-Lubeck Well Field and the East Well Field shown in Figure 2.4) lowers the groundwater level to below river stage. This induces water from the river to flow into the alluvium toward the wells, which replaces water pumped from storage in the aquifer, and helps sustain high-yield pumping wells. BEft ^ CORKMWE HBMHXATIOHOIIOUP ChAri wf DM WC QtoimrfOmfl w^SSiSS'SSw C:^MARVW20a7205RF|,D0030-JUN-&3\7205 EID090362 SECTIOHTWO _______faeimypescrtpuon 2.4 REGIONAL GROUNDWATER AND SURFACE WATER USE Regional groundwater supplies are obtained from the Dunkard Group bedrock and Ohio River alluvial terrace deposits. The saturated portion of the Ohio River alluvial terrace deposits comprises the principal regional aquifer used for water supply purposes. Production wells completed in this aquifer have been known to yield up to 500 gpm (Schultz, 1984). Based on these high yields, numerous industrial and commercial water supply companies obtain water from the alluvial aquifer. The yield from alluvial aquifer wells is related to the well's position with respect to the river, as well as formation grain size and thickness. The groundwater quality in the alluvium in mis region tends to be naturally poor, having the highest median chloride, sulfate, hardness (as calcium carbonate), iron, and manganese concentrations of all hydrogeologic units in the region (Schultz 1984). Water from the alluvium generally is a calcium bicarbonate type, with near neutral pH and high dissolved solids content. The underlying Dunkard Group bedrock generally only yields enough water for domestic and farm use. Median yields for valley, hillside, and hilltop wells were 6.5,2.0, and 3.0 gpm, respectively (Schultz 1984). Except for a few localized areas where fractures are plentiful, there is little potential for higher well yields. Waters in the Dunkard Group generally are a sodium bicarbonate type (Schultz 1984). Regional surface water use is primarily satisfied by the Ohio River and Little Kanawha River near Parkersburg. These sources provide water to the cities ofParkersburg, West Virginia, and Belpre, Ohio. In less congested areas (i.e., near the DuPont site), the local communities receive water from small local water companies that obtain their water from production wells screened in the Quaternary river alluvium. 2.5 LOCAL GEOLOGY AND HYDROGEOLOGY The uppermost geologic unit directly below the plant consists of Ohio River terrace deposits of Pleistocene age. The total thickness averages approximately 60 feet along the riverbank and approximately 100 feet to the south. Along the riverbank, this unit consists of silt, clay, and fine grained sand to approximately 20 to 30 feet, followed by approximately 20 to 30 feet of coarse sand and gravel, which extends down to the top of the bedrock (part of the Permian-age Dankard Group). To the south on the main plant area and above the riverbank, approximately 10 to 20 feet of silt, clay, and fine-grained sand overlie approximately 80 to 100 feet of sand and gravel to approximately 90 to 120 feet deep (the top of bedrock). These deposits are laterally continuous throughout the site. Site geology is shown on six geologic cross sections developed during the April 1992 VI (DuPont, 1992) and revised based on additional findings from this investigation. The locations of the geologic cross sections are shown in Figure 2.5. Two east-west geologic cross sections, A-A' and F-F', are shown on Figures 2.5A and 2.5F. Four north-south cross sections, B-B', C-C', D-D', and E-E' are shown on Figures 2.5B, 2.5C, 2.5D and 2.5E, respectively. The cross sections were developed from detailed geologic logs obtained during the VI and RFI, and from less detailed historic geologic logs from test and production wells and geotechnical borings drilled in the late 1950s through the early 1980s. ngMB ^^ cwpauTfRaw<a<aiM> OlfatfMtfDrWCaimriOffiw MWMKW.UIB I o C:\MARW20aroi5WI.D0029..1UN-997Z05< 2-3 Q --1 EID090363 SEGTIflHTWO_________________Facility Description The bedrock unit that underlies the Ohio River terrace deposits consists ofinterbedded sandstones, siltstones, claystones, shales, occasional limestones, and coal zones. This formation belongs to the Permian-age Dunkard Group. Soil borings drilled in the early 1970s at the northwest comer of the site indicate that the top of the bedrock zone, which immediately underlies the upper alluvial sand and gravel of me Ohio River terrace deposits, is shale at approximately 530 feet above MSL. To the south of the plant toward the edge of the Ohio River depositional valley, the Ohio River terrace deposits thin out. Bedrock of the Dunkard Group is present at the ground surface south of the site at me Local Landfill. Due to riverbank undercutting, some slumping of clay and silt exists along the northern boundary of the property along the river's edge. An interpretation of the typical Ohio Riverbank stratigraphy is presented in Figure 2.6 (Cariston and Graeff 1955) and correlates well with the geologic data obtained from the borings completed along the riverbank. Seeps located along the riverbank appear to be precipitation that has infiltrated topsoil or fill and that flows along the top of the underlying shallow clay and discharges along the riverbank. Figure 2.5C shows an example of the relationship of fill and clay layers along the riverbank. The Ohio River alluvial terrace deposits comprise the principal aquifer underlying the site, hereafter referred to as the "site aquifer." The water table occurs at a depth of about 60 to 70 feet bgs in the main plant area. The saturated zone is approximately 30 to 40 feet thick, extending to the surface of the underlying Dunkard Group. The on-site production water wells completed in the site aquifer yield 200 to 450 gpm. As discussed in Section 2.4, the underlying Dunkard Group is not a major aquifer, m fact, the upper zone of the Dunkard Group, primarily a shale and silt matrix, bounds the lower portion of the site aquifer and serves as a confining unit to underlying geologic units. 2.5.1 Groundwater Flow Directions Groundwater flows to the south-southwest in the Washington Works site aquifer. However, groundwater elevations, flow directions, and flow rates on-site are strongly influenced by the Ohio River and by pumping of on-site production wells. The Ohio River is the primary source of recharge to the site aquifer. The on-site production wells are the Ranney Well, a radial collector well which pumps 800 to 1,000 gpm; the seven wells in the East Well Field, which pump a combined average rate of 2,000 gpm; and the five DuPont-Lubeck wells, which pump about 700- gpm combined. Groundwater elevation contour maps developed from data collected in November 1998 and February 1999 are presented'as Figure 2.7 and Figure 2.8, respectively. The direction of groundwater flow in the site aquifer is indicated by the flow arrows. As shown on the groundwater elevation contour maps, groundwater flow in the northeast part of the site is toward the East Well Field wells from the south and from the north, m the north-central portion of the site, groundwater flow is toward the Ranney Well. In the central and western portion of the site, groundwater flow is south-southwest towards the DuPont-Lubeck Well Field. Pumping of the production wells (Ranney Well, East Well Field, and the DuPont-Lubeck Well Field) eliminates off-site migration of groundwater which may emanate from the SWMU areas. <ssss ^ CORPOUfC RBMCDUTMN OROjr DiAM-w n-wcotemjaw^ I ---------------------- ^ 0 C:WRW20W72()5RFI.DOCa9-JUN-9720a 2-4 g 000\ EID090364 SEGTIONTWO facility Descripaon 2.5.2 Transmissivity, Hydraulic Conductivity, and Groundwater Flow Velocity In a 1990 hydrogeologic assessment, production well specific capacity testing of the DuPontLubeck Well Field-and the East Well Field was conducted. The results were used to calculate the transmissivity of the site aquifer (DuPont 1990). The results indicated that the transmissivity values for the site aquifer in the vicinity of the DuPont-Lubeck Well Field appear to be higher than the values calculated in the vicinity of the East Well Field. In the vicinity of the DuPont-Lubeck Well Field, transmissivity values ranged between 114,900 and 127,500 gallons per day per square foot (gpd/ft2). In the vicinity of the East Well Field, the values ranged between 16,050 and 50,000 gpd/ft2. The differences in the shape, depth, and extent of the cones of depression between these two areas support the transmissivity values calculated. In the same 1990 hydrogeologic assessment, hydraulic conductivity values were calculated from the transmissivity values for the East Well Field. For Wells 335 and 337, the hydraulic conductivity values ranged from 0.00042 to 0.0018 feet/second (ft/sec) and from 0.00033 to 0.0016 ft/sec, respectively. Using the hydraulic conductivity values from the 1990 study and the hydraulic gradient values determined from groundwater elevations measured in 1990 and assuming an effective porosity value for sand and gravel of 35 %, the groundwater flow velocity for several well pairs was calculated. The groundwater flow velocity was estimated at 5 feet/day (ft/d) between monitoring wells TW-24 and TW-27 in the southwest portion of the site. A groundwater flow velocity of 3 ft/d was estimated between monitoring wells TW-33 and TW-M4 in the western central portion of the site. In the eastern portion of the site, a groundwater flow velocity of 1.5 ft/day was estimated for the site aquifer between monitoring wells TW-M1 and TW-26. 2.6 SURFACE WATER Surface water at the Washington Works facility is considered to be the Ohio River, drains and storm sewers, seeps at the riverbank, and drainage swales. The average river water elevation is about 580 feet above MSL and the elevation of the Ohio River terrace deposits under the main plant is about 630 feet above MSL. The Ohio River is the main recharge source to the site, aquifer. A large portion of the plant site is covered with asphalt and concrete. Therefore, much of the precipitation falling on site is routed toward drains and storm sewers, which ultimately discharge into the Ohio River. Precipitation falling on the riverbank slope either percolates into the soil or runs off to the river. In addition, the seeps that occur in places along the riverbank are probably caused by percolated water that accumulates above the slumped, low-permeability clay and silt of the Ohio River deposits that underlie topsoil and fill along the riverbank. Precipitation falling on the unpaved southern portion of the site most likely migrates downward toward the unconfined water table, but may be limited by the shallow layers of clay and silt of the Ohio River terrace deposits. <M ^ COWVHWtt REhEDIATION QROUP AlAMWMMM OAriwtf ffw WC Otamrianf 1m hM Pteu. IdUng ir 1MM<^an;(Mw IMWnr > CO t-rt C:MARYW205\7208RFI.a0029-.)UN-9Bl720St 2-5 0 0 S 00\ EID090365 SEGTIONTWO Facility Description Two drainage swales, one located in the facility's southwest comer, and the other located on the extreme eastern end of the facility, also convey surface runoff during rainy weather to the Ohio River. During dryweather. the drainage swales are dry. 2.7 KNOWN RELEASES FROM SITE SWMUs Previous investigations presented in the VI Report (DuPont 1992) and summarized in the RFI Plan (DuPont 1997) found evidence of releases of organic constituents and possibly metals to soil and groundwater at the RBL, ADP, and BG. Little evidence of release was found in soil at the site of the former PWI. At the RBL/ADP area (in the western portion of the RBL), several organic constituents and metals were detected in groundwater or seep samples that exceeded health-based screening criteria for drinking water. These constituents included methylene chloride, Freon-113, tetrachloroethene (PCE), trichloroethene (TCE), arsenic, cadmium, and lead. PC-143 and Triton-X were also detected in groundwater and seep samples in this area. Soil samples that were collected in the vicinity of the RBL/ADP during the VI did not have significant levels of site-related constituents, indicating that releases to groundwater and to surface seeps are the chief migration pathways from these SWMUs. The source of release may be the RBL, ADP, or both. The main seep area (RBLL1) at the RBL/ADP, where methylene chloride is the primary constituent, has been controlled by a french drain and carbon adsorption treatment system since 1990 (see Figure 4.1). A key objective of the RFI was to determine if this containment system is effective at preventing off-site migration. The BG ceased operation in 1965 and, since 1990, the site has been leveled with clean fill and gravel and overlain in part by buildings and asphalt. A potential release of organic constituents to groundwater was identified in me VI, in that carbon tetrachloride, PCE, and TCE were detected in concentrations above screening criteria for drinking water. FC-143 was also detected in groundwater. Arsenic, lead, and nickel were detected above MCLs in unfiltered samples but not in filtered samples, suggesting that the presence of these metals in groundwater is probably not due to leaching from soils at the BG. Soil samples did not have significant levels of site- related constituents, although barium and methylene chloride concentrations exceeded screening criteria for the soil-to-groundwater pathway (these constituents were not detected in groundwater above MCLs). An objective of the RFI was to determine if the BG was the source of the constituents identified in groundwater during the VI, or whether these constituents originated from the RBL. The PWI was excavated (i.e., ash material was removed) and back filled with clean soil in early 1990. There is no evidence of significant releases to adjacent soil at the site of the former PWI because metals concentrations in soil samples did not exceed risk-based screening criteria or background levels (VI Report, DuPont 1992). Additional sampling for chromium is included in the RFI to confirm the conclusion, since chromium was omitted from the VI analytical list. Releases to groundwater are not a concern at this SWMU. <lfflB> ^ CORPORATR lUMBiwnoMawur MMhmMMM tkArt (Ite WC OlM--tf Onif > CO 2-6 s CaMARY\7205l7205RF1.00029-AIN.972aa 0 0 s -~J 0 EID090366 SEBTICNTHREE__________RCRfl Facility flemnvestigalien The RFI was designed to delineate the impact to soil and groundwater associated with potential releases from the four SWMUs, and to gain a better understanding of site geologic and hydrogeologic conditions so that constituent transport can be predicted. The RFI was also intended to identify potential exposure pathways and assess potential concerns for human health and the environment. The field investigation was conducted in accordance with the RFI Plan (DuPont 1997) and included the following primary field activities: Q Site-wide monitoring well installation Q Site-wide groundwater sampling (2 rounds) Q Background soil sampling Q SWMU-specific soil sampling and groundwater sampling (2 rounds) Site-wide monitoring well installation and soil sampling activities were conducted from August through October, 1998, Two comprehensive groundwater sampling events were conducted in November 1998 and February 1999 respectively, after all monitoring wells were installed and soil sampling was completed, Soil and groundwater are the two environmental media that were sampled and.analyzed during the RFI. The sections that follow provide detailed information on the sampling methods, locations, depths, and analytical parameters for each medium. Sampling locations and depths were selected to provide data representative of current site conditions. Analytical parameters were determined based on data collected at each unit during previous investigations. Table 3.1 describes the number and depth of borings at each investigation area. Table 3.2 summarizes the completed analytical parameters and test methods. 3.1 SOIL SAMPLING METHODS Surface soil samples were collected from 0 to 2 feet below ground surface (BGS) using a stainless steel, hand-operated auger or split-spoon sampler. Borings were advanced using a truck-mounted drilling rig with hollow-stem augers. Continuous split-spoon samples were collected at 2-foot intervals per American Society for Testing and Materials (ASTM) methods, if a drill rig was used. In areas of the site which were inaccessible by a truck-mounted drilling rig or where sample locations were shallow, a stainless steel hand auger was used to collect the samples. Soil sampling locations are indicated on Figure 3.1. During soil sampling activities, all intrusive work was monitored with a photoionization detector (PID) or a flame ionization detector (FID) as a means of screening spatial and vertical differences of volatile organic vapors at the various sampling locations. Monitoring was conducted to fulfill requirements of the Health and Safety Plan included in the RFI Work Plan and to assist in sample screening. oflOb ^ com>oiun MMCOMIM mow DkAMfMU Hi* IWCOrwMWOfMW --((Mlinui.WKkgl? C:<MARY<7ZOSi7205RF1.00029-JUI<-9720a 3-1 gs a 0 0 (s> -J EID090367 SEGTBBNTHREE____ BBBflFacility neM instigation In general, samples were collected in the following order to reduce the loss of volatile components: Q Volatile organic compounds (VOCs) Q Extractable organics Q Metals 0 Indicators (BOD, chloride, ethane, ethene, methane, nitrate, sulfate, sulfide, TOC) Upon sample retrieval, the VOC sample containers were filled immediately by transferring soil from the sampling device with a stainless-steel scoop or trowel. The section representing soil from the lS-to-24-inch interval (BGS) was collected for VOC analysis because volatile organics in the deeper portion of the core are less likely to have volatilized to the atmosphere. The VOC sample containers were filled completely and packed to minimize sample headspace. The remaining soil in the sample was screened for VOCs using a PID or FDD. The soil was then transferred to the remaining sample containers using a stainless steel scoop or trowel. Collecting the sample for VOC analysis prior to performing headspace analysis minimizes the loss of VOCs from the sample prior to analysis. After me sample containers were filled, they were labeled and placed in a sample shuttle containing ice or ice packs. All samples were kept at approximately 4C during storage and shipment. All equipment used to collect me soil sample was decontaminated prior to each use according to the general decontamination procedures discussed in Section 3.11 of this report. During sample collection, a geologist recorded soil descriptions on the basis of visual observations in accordance with the Unified Soil Classification System (equivalent to ASTM D2487 69). Boring logs that provide a description of the penetrated soil profile were completed for each sample (see Appendix E). All PBD/FED readings were noted on the boring logs. Upon completion of sampling, all borings were either tremmie grouted using an appropriate grouting mixture or filled with bentonite pellets if the location was sampled using a hand auger. ."'t 3.2 SITE-WIDE MONITORING WELL INSTALLATIONS The RFI field investigation included installation of 24 site-wide monitoring wells to supplement the existing monitoring wells within or near the specific SWMUs being investigated. Monitoring well locations are indicated on Figure 3.2. In general, the new monitoring wells were installed to satisfy site aquifer hydrogeologic (i.e., piezometric head) data gaps. In addition, two wells were installed near the western plant boundary line (i.e., the boundary with GE) to determine piezometric head and groundwater quality. The 24 new monitoring wells were installed at locations based on the Site Conceptual Model presented in the RFI Work Plan (DuPont 1997). A preliminary site-wide groundwater flow model was completed and presented to the USEPA Region ffl in August 1998. (RFI Work Plan: OBB ^ annMimmwwtmtwsw ouArt a-rf n we OAMwrf omiw brfw M Pted fcJ*q 2f MMntfmOit--m vsuawa ---------------------- ^ w g 0 C:\MARW205205RFI.DOQ2-,)UN-97205\ 3-2 ^ EID090368 SEGTIONTHREE BORAFacility Held investigation Groundwater Model Update Report). There were no changes to the proposed sampling locations based on the preliminary model results. All new wells were-mstalled with a truck-mounted drilling rig with hollow-stem augers. The soil was continuously sampled with split spoons for lithologic logging if the monitoring well was associated with a SWMU. For background monitoring wells, as well as V06-MW01 and W05MW01, lithologic logging was performed with split spoons samples collected approximately every 5 feet. During monitoring well drilling, soil samples were collected from various depths based on visual observations and PID/FID readings. The soil samples were analyzed for the specific parameters listed in Table 3.2. Lithologic logs were completed during the drilling activities. The lithologic logs and well construction diagrams are included as Appendix E and Appendix F, respectively. 3.2.1 Monitoring Well Construction Monitoring wells were constructed according to West Virginia Monitoring Well Design Standards 47 CSR 60. No more than 20 feet of screen for each well were used during well construction activities. Soil borings were advanced until contact with the water table and then advanced another 10 to 15 feet. Well screens were installed to straddle the entire saturated thickness encountered in the borehole. All new monitoring wells were constructed with flushjointed, Schedule 40, polyvinyl chloride (PVC), 2-inch diameter pipe. Each well was installed with a threaded PVC plug on the screen bottom. The annular space around the screen was filled with gravel pack using an appropriate sand for the screen size. The gravel pack was extended 2 feet above the top of the screen. Gravel pack placement was confirmed by line measurements made through the annulus of the borehole to prevent sand bridging. A 2-foot-thick bentonite pellet seal was placed above the gravel pack. Seal placement was also confirmed by line measurements through the annulus of the borehole. Once in place, the bentonite seal was hydrated with water from the Blennerhassett Island pumping wells. The remainder of the well annulus to ground surface was tremmie grouted with a cement/bentonite grout that was mixed according to one of the following specifications: Q Cement-bentonite--8 gallons of water to 5 pounds of bentonite dry mixed per 94"-pound bag of cement Q Cement-bentonite--10 gallons of water per 8 pounds of bentonite water mixed with a 94-pound bag of cement Protective 6-inch outer steel casing, locking cap, concrete pads, and traffic posts were installed for all wells in non-trafficked areas. Traffic bollards were installed for all stickup wells near roadways. Wells that were installed in heavily trafficked areas or roadways were completed with a Momson-Dubuque type flushmount. All RFI drilling was performed by a West Virginia licensed/certified well driller. Well logging and installation was supervised by a team of qualified geologists and engineers. All newly ^ wvEMUsawncMcawr JnjUtemAib--t tf n* W6 Ote--^OMW WMHm.VM^lf ^ 3-3 S C:lMARW20S\7205RFI.Ot>a3(MUN-99\72oa - - 0 ^ (jj EID090369 SECTIONTHREE ReRAFacUKyField Investigation installed monitoring wells were registered by the driller within the state of West Virginia as per 47 CSR 60. All new wells have also been labeled by permanently affixing the West Virginia registration number to the protective casing or flushmount. Well construction information is summarized in Table 3.3. 3.2.2 Monitoring Well Development The new wells were allowed to cure a minimum of 12 hours before being developed. Each new well was thoroughly developed by pumping and/or bailing to remove fines from the screened interval. Total well depths necessary to calculate the required purge volumes were tabulated after completion of the well installation and accompanied the sampling team in the field. All wells were developed for a minimum of one hour until at least ten well volumes had been purged and turbidity levels visibly decreased. All development water was contained and disposed of as described in Section 3.10 of this report. Well development information is summarized in Table 3.4. 3.3 SITE-WIDE GROUNDWATER SAMPLING A total of 37 new and existing wells were sampled on two separate occasions during the RFI field investigation. These included one potable water well, four production wells, eight existing monitoring wells, and 24 newly installed monitoring wells. The first groundwater sampling event was conducted after all new monitoring wells had been installed and developed during the first and second weeks in November of 1998 (see Figure 3.2). The second groundwater sampling event was conducted during the first and second weeks in February of 1999. Well Q05-MW01 was not sampled during Round 2 because of insufficient water volume due to dry weather. Field location maps were prepared from survey data for the newly installed monitoring wells. Prior to groundwater sampling, the depth to water was measured in each new and existing well that was accessible, and water level elevations were calculated for each sampling event based on new survey data (see Tables 3.5 and 3.6). This data was then-used to prepare the water level contour maps depicting the groundwater gradient maps that are presented in Figures 2.7 and 2.8. .i-. To minimize the potential for crass-contamination, monitoring wells were evacuated and sampled beginning from the well with the highest potential for contamination to the lowest. The sampling order of the wells from most to least contaminated was based on data from the VI (DuPont 1992). Prior to sample acquisition, monitoring wells were purged a minimum of three volumes of water standing in the well casing by using a low-flow submersible pump. A few of the wells were purged and sampled with a disposable polyethylene bailer because the water column was not large enough to allow the use of a submersible pump. The depth of the purge pump intake depended on well yields. The ideal intake for the pump was at the static water level in the well. The pump intake was adjusted as the water column responded to pumping. Measurements ofpH, specific conductance, turbidity, dissolved oxygen, temperature, and salinity were collected by use ofaHoriba U-10 instrument during well purging. Purging was <SS3K> ^ CORPORA TEROifixATiQN GROUP OArtjnf nrMlirOtoncWnnmi jrt^MiftoLMiiwir C:<MWW20a7205f(F1.00CQ9-JUN4a720a 3-4 g 0 4^ EID090370 SECTIOMTHREE BBBflfaclBtyHeM investlBatlon completed when at least three well volumes had been evacuated and three consecutive readings ofpH and specific conductance had stabilized to within 10 %. When purging was complete, the well was allowed tojscharge and then sampled. All wells were sampled with a disposable polyethylene bailer and dedicated bailing twine. Dedicated, disposable tubing was used during well pumping. Proper decontamination was performed during well sampling to prevent crosscontamination within and between monitoring wells, as described in Section 3.11. Monitoring instruments and the submersible pump were cleaned with an Alconox detergent wash followed by a deionized water rinse. All purge and decontamination water was containerized and disposed of as described in Section 3.10 of this report. 3.4 SWMU-SPECIFIC SAMPLING After review of VI data, SWMU-specific soil and groundwater sampling activities were planned and presented in the RFI Work Plan (DuPont 1997). The sampling programs described below allowed delineation of extent ofmigration of SWMU-specific constituents. 3.4.1 SWMU A-3--Riverbank Landfill (RBL)and SWMU B-4--Anaerobic Digestion Ponds (ADP) Field investigation activities at the RBL and ADP SWMUs have been grouped together due to their close proximity. Soil boring and monitoring well sample locations are shown on Figures 3.1 and 3.2, respectively, m general, the sample locations were established to determine the vertical and lateral extent of waste constituents migrating from these units. Three shallow soil borings and three monitoring well locations (well locations include both a soil boring and a monitoring well) were completed for the ADP to evaluate FC-143 concentrations in soil and groundwater and potential migration pathways. In addition to the new RFI soil borings and monitoring wells, the field investigation at the ADP included groundwater sample collection from Q04-MW01, Q05-MW01, P06-MW01, and P08-MW01, part of a series of six new monitoring wells installed in June 1997 that are situated within or near the ADP boundary. A detailed investigation was conducted at the RBL seep area (RBLL1) (see Figure 4.1). An active French drain groundwater collection and carbon adsorption system has been in operation at RBLL1 since 1991. Six shallow soil borings and three shallow monitoring wells were installed in this area to determine the extent ofmethylene chloride impact to shallow soil and seep water. This investigation also helped to verify that the current collection and treatment system is effectively capturing the affected water at the RBLL1 seep area, and thus remains a successful ongoing corrective measure. The rest of the RBL was investigated on a broader basis, with the objective being to determine whether impacts to shallow soil or groundwater have occurred, and, if so, determine the direction of constituent migration. Along the length of the north side of the RBL (i.e., riverside), 15 shallow soil borings were installed, approximately 100 to 140 feet apart. Shallow monitoring wells were installed at seven additional soil boring locations for a total of 22 soil sample sites. ^ CCIWaMISmMBOWlWMWKW A^rfMrf Th WGOtaiMHrfOnw kV Ml Pta. BifUiq 2T C:lMARW20Sff205RFI.D002JUN-9S\721)5 3-5 I U EID090371 SECTMMTHREE BCM Facility HeM InvestlBaflon The south side of the RBL was investigated along its entire length in a manner similar to the north side. Eight new monitoring wells were installed and two soil borings were completed along the south side of the RBL in an effort to supplement the existing well system. The wells were drilled just off the southern boundary of the RBL, since the SWMU area itself is inaccessible due to the presence of dense vegetation. Soil samples were collected from several depth intervals during the drilling investigation (see Table 3.1). Six monitoring wells installed in June 1997 assisted in evaluating the potential migration of constituents from the RBL and ADP. As with all of the wells included in the RFI field investigation, these wells were sampled twice for the analytical parameters listed in Table 3.2. 3.4.2 SWMU C-6--Polyacetal Waste Incinerator (PWI) Per USEPA Region ffl comments (EPA 1997) on the VT data from this SWMU, the field investigation at the PWI consisted of two soil samples collected with a hand auger at locations equivalent to the VI soil borings. Soil samples were collected from the surface (0 to 2 feet) and analyzed for chromium. 3.4.3 SWMU H-14--Burning Ground (BG) The RFI field investigation included a comprehensive evaluation of soil and groundwater quality underneath and near the BG. Seventeen soil borings and five new monitoring-wells were completed to determine the vertical and lateral extent of waste constituents migrating from this unit (see Figure 4.10). Soil boring locations were chosen within a statistically based 35-foot spaced grid. The locations were chosen based on the existence of numerous buildings in this area which prevented evenly spaced sampling points. Soil borings included sample collection with depth to delineate vertical distribution of potential constituents of concern. The sampling frequency and analytical parameter list are provided in Table 3.1 and 3.2, respectively. Based on the Site Conceptual Model, groundwater flow beneath the BG is mostly southwest toward the DuPont-Lubeck well field during pumping. The monitoring wells completed at the BG were designed to evaluate downgradient groundwater quality along this migration patBway. A separate monitoring well completed north of the BG and south of me RBL (AA05-MW01) was installed to aid in differentiating groundwater quality impacts between the two SWMU areas. 3.5 BACKGROUND SOIL SAMPLING Twelve background soil samples were collected at ten borings at locations on the Washington Works site where, to the best of our knowledge, no manufacturing or waste management activities have been conducted. Background sample locations are listed in Table 3.1 and shown on Figure 3.1. All samples were collected from the same site-wide soil horizon that is present below or near the SWMUs being investigated. The background soil data set provides site-wide coverage of spatial variations in background metals concentrations, which may result from ^ ChftnfMtf n> WC ObnwJ 0 ------------------------------------------ ^ C/3 g CaMARY\7205r205RFI.DOC\29-JUN-99\7205l j-i-6r 0 0 tsl s^ EID090372 SEBTiOMTHREE__________BGM faelliCf neM invesilBaflon natural geologic processes. The background soil samples were analyzed for the following analytes: arsenic, barium, cadmium, chromium, lead, nickel, methylene chloride, tetrachloroethene,Jrichloroethene, andFC-143. 3.6 SOIL GEOTECHN1CAL ANALYSIS During the RFI field investigation, soil samples were collected for laboratory geotechnical analysis from the RBL and BG SWMU areas. The geotechnical samples were collected via a 3foot-long, 3-inch diameter, hydraulically advanced, Shelby tube sampler and analyzed for the following: Q Grain size (sieve analysis) Q Moisture content Q Atterberg limits Q Porosity Q Vertical permeability Q Horizontal permeability The four Shelby tube soil samples, two from the BG and two from the RBL, were collected at locations already designated for soil boring/well installation. In general, the samples were collected from differing lithologies that represent the various soil types throughout the site. 3.7 SLUG TESTING As a supplement to the permeability assessments conducted on the geotechnical samples, slug tests were performed on several newly installed wells throughout the site. Fifteen new wells were tested to provide hydraulic conductivity results throughout the site. The fifteen wells were slug tested during the first round ofgroundwater sampling in November 1998 after all wells had been properly developed. m-situ permeability of the screened interval for each well was evaluated by the instantaneous removal and insertion of a well slug with a known volume. The response of the removal and insertion was measured in the well with pressure transducers and Hermit data loggers. Data was reduced using the Bouwer and Rice method for imconfined aquifers. Results of the slug tests were used in calibrating the groundwater model described in Section 5. <SSBi ^ GORPOIUTSflMDumOMIWOUf AlJUtmAfMl OArt ri n-MU: CKMMIJOioyr > S 1 1 1^-1 C;MARY\7207205RFI.DOCUO-AN-97205k -''' 0 0 3 EID090373 SECTIOMTHREE RGRAFacility Field investigation 3.8 REVISED NOMENCLATURE A site-wide alphanumeric coordinate system was developed to facilitate unique nomenclature for proposed and pre-existing wells and soil borings. This coordinate system allowed modification of the existing soil boring and monitoring well locations while maintaining an easily usable and understandable system of nomenclature. A 200- by 200-foot grid was superimposed on the DuPont Coordinate System. Each column (from east to west) was assigned a letter from A to BE. Each row (from north to south) was assigned a number from 1 to 27. Hence each cell in the grid has a unique identifier (i.e., AP13, BA05). All pre-existing wells and soil borings were then renamed according to the cell location and the type of sample. The following convention was used: MW for Monitoring wells, PW for production wells, and SB for soil borings. For example, two monitoring wells in cell AP13 were renamed AP13-MW01 and AP13-MW02. After all preexisting wells and soil borings were renamed, RFI specific wells and soil boring locations were selected and named. Figure 3.2 shows the revised names for the preexisting wells and soil borings, as well as the completed RFI wells and soil borings. 3.9 SURVEYING All sample locations were surveyed once the soil sampling and well installation program was completed. All well locations were surveyed and four measurements were recorded. The elevation of the ground surface and the top of the PVC casing was surveyed to the nearest 0.01 foot using the nearest convenient permanent surveyed benchmark. Horizontal locations (i.e.. Northings and Eastings) of the wells were surveyed to the nearest 0.01 foot. Each of the new wells were marked on the top of the PVC riser pipe to identify the surveyor's reference point and to standardize the measuring point for depth to water measurements. Soil boring and hand auger locations were surveyed and three measurements were recorded for each point. Horizontal locations and ground surface elevations were recorded to assist in proper data analysis and cross-section representation. '-. 3.10 WASTE MANAGEMENT Waste management procedures are described in the Waste Management Plan (see Appendix F of the RFI workplan). Each waste stream produced during the RFI was handled in the appropriate manner as discussed in the following text. The typical wastes that were generated and managed during RFI activities included: Q Soil cuttings from drilling and augering activities Q Water from purging and development of monitoring wells 0 Water from decontaminating sampling and drilling equipment vsssa ^ COHWW.V HOWWKM WWW CaMARW20a7205RFI.D002MUN-9720a 3-8 EID090374 SECTBOMTHREE RGRAFacility Field investigation 0 Disposable sampling equipment Q Disposablejzersonal protective equipment (PPE) 0 General construction debris Soil cuttings that were produced during the RFI drilling and augering programs were contained in 137 polyethylene. Department of Transportation (DOT) approved drums. All drums were labeled, dated, logged, and staged on-site to await characterization. Analytical samples from the associated soil borings were compiled to determine the status of the soil contained in each individual drum. Additional samples were collected and analyzed following the RFI program to further assess the status of individual drums. All drums were classified as non-hazardous and will be properly disposed of off site. Development and decontamination water produced during the RFI activities was contained in a 21,000-gallon portable tank staged near the decontamination area. Approximately 3,500 gallons of waste water was produced during the sampling activities. A Toxicity Characteristic Leaching Procedure (TCLP) sample of the waste water was collected and analyzed following the RFI activities and results were compared to TCLP criteria for waste disposal classification. The waste water was classified as non-hazardous and pumped into an over-the-road tanker truck for transportation to the DuPont Chambers Works facility in Deepwater, New Jersey, for proper disposal. Disposable PPE and sampling equipment were contained in drum liners at the end of each day. The drum liners were sealed after they were filled and deposited into an on-site waste dumpster for proper disposal. 3.11 DECONTAMiNATION Proper decontamination was performed during sample collection to prevent cross-contamination within and between sample locations. Prior to moving onto a new location, the drill rig and associated equipment were thoroughly cleaned at the decontamination pad constructed in the East Well Field area of the plant using a pressurized steam cleaner and BIennerhassett Island water. "' Sampling equipment included drilling rigs with augers, hand augers, split-spoon samplers, trowels, spoons, mixing bowls, spatulas, bailers, tubing, and pumps. All of these items came into direct contact with the sample and had a potential to impact analytical results. Therefore, care was taken to ensure the cleanliness of all sampling equipment. When possible, laboratorycleaned or disposable sampling equipment was used (e.g., bailers for sampling wells). Sampling devices (i.e., split spoons, hand augers, and stainless steel sampling spoons) were cleaned, at a minimum, by an Alconox detergent scrub and a BIennerhassett Island water rinse after each use. All well riser pipe and screen used for well construction was certified cleaned and wrapped by the distributor. During drilling and well construction activities, vegetable oil and other nonpetroleum based products were used as lubricating oils to minimize potential SSSSS ^ COWCWATI RCMUXATIONOnOUP BiArtM rkwHKCOMMntfOMqp C:lMARyV20a720SRF).DOCtt9-JUN-B9\7205\ 3-9 EID090375 SECTIONTHREE RBRAFacility Field Investigation contamination of the borehole and/or well. All excess soil cuttings and decontamination water were contained and will be disposed of as per Section 3.10. All equipment in direct contact with the material to be sampled was decontaminated prior to sampling to prevent cross-contamination of the collected samples. In addition, care was taken so as not to allow anything to come into contact with a sample or sample area which could affect its composition. In addition to the decontamination procedures outlined above, the person collecting the sample wore clean, disposable latex gloves and limited his/her contact with the samples. Sample bottles and containers were prepared by the contracted laboratory and were sealed to ensure cleanliness. Sample bottles were not cleaned or reused in the field. The drilling augers, well casings, well screens, and hoses were pressure washed prior to use, unless certified clean and wrapped prior to transport to the site. A personnel decontamination area was established at each sample location prior to start of sampling. Procedures for the decontamination of protective equipment and the removal of respiratory and personal protection clothing to avoid transfer of constituents from clothing to the body are discussed in the Health and Safety Plan (see Appendix E of the RFI workplan). 3.12 QUALITY ASSURANCE/QUALITY CONTROL Several quality assurance/quality control (QA/QC) methods were conducted during the field activities to ensure quality data collection and analyses. Trip blanks, duplicate samples, matrix spike/matrix spike duplicates (MS/MSD) samples, and equipment blanks were collected during the field program to assure field procedure and laboratory quality. A trip blank consisted of a sample container filled at the laboratory with analyte-free or deionized water. The trip blank traveled to the site with the empty sample bottles and back from the site with the collected samples in an effort to simulate sample handling conditions. Trip blanks were not opened in me field. Trip blanks were shipped and analyzed for each shuttle of VOC that was collected in a day's period. The trip blanks served as a check on sample contamination originating from container migration or from sample transport. Duplicate soil and water samples were obtained by alternately filling sample containers from the same sampling device for each parameter. Media to be analyzed for VOCs were collected first. - Duplicate samples were collected at a rate of one in twenty for each appropriate type of matrix and parameter. Duplicate samples were collected to evaluate the aggregate sampling and analytical precision. MS/MSD samples were also collected at a level of one in twenty. MS/MSD samples were collected to provide a method of accuracy in a given matrix. The MS was performed by adding a predetermined quantity of stock solutions of certain analytes that are representative of test constituents to a sample matrix prior to the sample extraction/digestion and analysis. The concentration of the spike was at me regulatory standard level or above the method detection limit. The MSD was collected as a duplicate to the MS to further demonstrate analytical accuracy. <BB) ^ WHVWUOtWMttATWUWmP C:lMARyi7205\7205RFI.D0029-JUN-99<7205\ 3-10 EID090376 SEGTIONTHREB RCRAFacility Fiehl Investigation Equipment blanks (also called rinsate blanks) were used to evaluate equipment cleaning and decontammation procedures. At the sample location, analyte-free water or deionized water provided by the laboratory was poured over or through the sample collection device, collected in a sample container, and preserved as appropriate. One equipment blank was collected for every twenty samples. All QA/QC samples were handled, transported, and analyzed in the same manner as actual field samples. Blanks were held on site for the minimum number of days. The temperature of the blanks was maintained at approximately 4C while on site and during shipment. Holding times for individual parameters were dictated by the specific analytes being tested and the analytical method being used. Samples collected were packaged in accordance with the Quality Assurance Project Plan (QAPP) and shipped under chain-of-custody to the laboratory using an overnight service (Federal Express) or laboratory courier. 3.13 SAMPLE PRESERVATION All sample containers were received from the laboratory containing proper preservatives for the method analysis except for the dissolved metal sample containers. Field filtering for dissolved metals species in water samples was completed and the preservative was added to the sample aliquot once filtering was completed. Field filtering was performed using a 0,45-micron filter, a peristaltic pump, and dedicated Tygon tubing. 3.14 FIELD CUSTODY PROCEDURES At the time of sample collection, the following field activities were performed and documented by the investigator: Q All procedures regarding preparation of reagents or supplies that were used in sample collection and/or sample preservation. Q Sample quantity, type (i.e., composite or grab), location, and depth was documented in the investigator's field log. Q Sample labels were prepared, and they included sample identification numbers, time and date of collection, proposed laboratory analyses, and name of sampler. Samples collected in the field by a team of investigators were the responsibility of each sampler until the samples were transferred to a person designated as the field sample custodian. Chains of Custody (COC) forms were required and completed for each sample collected in the field. Prior to sample transport to the laboratory, a COC form was completed by the field sample custodian. Sample locations, sample identification numbers, description of samples, number of samples collected, and specific laboratory analyses conducted on each sample were recorded on the COC forms. The field sample custodian signed and dated the COC form and retained a copy for the project records. <8B86 ^ COAfORATK REMBiHTKMfttfUUP fTifUnf nfi< TtuWCSViMMtViam BaterdWnmOdUkqZ? WlbWWM.CUw IMUOIOr > CO hg CAMARY^7^oa7^05Rf:I.DOC2JUN.99^720 3-11 0 00 EID090377 SECTIONTHREB RORfiFacility neM investigation Prior to sample shuttle delivery to the courier, the sample shipping containers (e.g., cooler, box) were sealed with the signed COC forms inside. After shipping and arrival at the laboratory, the authorized laboratory custodian who received the samples signed the COC forms, thus terminating custody of the field sample custodian. <vas> ^ OOWOAATB lUMEOATION gROUP (M>W(wWmWCOtecWlta^ 9frtftMHw.9uU^Sf CaMARYi7205\7205RFI.OOCl29-JUN-9g\7205\ 3-12 > i 0 00 (^) EID090378 SECTIOMFOUR___________BBM fteM Investigation Results The following section presents the RCRA Facility Investigation results. It is organized as follows: Q Data Qualt^Review Q Soil Investigation Q Groundwater Investigation In general, the results are presented and discussed on a SWMU by SWMU basis. To provide a qualitative guide to the level of observed impacts and to help assess their potential significance, all soil analytical results were compared to USEPA Region in Risk-Based Concentrations (RBCs) for industrial soil (USEPA Region III 1999). Groundwater results were compared to federal Maximum Contaminant Levels (MCLs) for drinking water or to RBCs for tapwater if no MCL was available. Concentrations ofFC-143 were compared to preliminary health-based screening levels for soil and groundwater that are derived in Section 6.4.3. Tables in Appendices A, B, and C show all analytical results in comparison to these screening criteria. Where relevant, the RFI results were discussed in relation to VI results to confirm consistency of findings or delineate migration pathways. 4.1 DATA QUALITY REVIEW The groundwater and soil samples were collected, analyzed, and reviewed according to the QA/QC requirements stated in the QAPP, with the exceptions noted in Sections 4.1.2 and 4.1.3. Sample custody at the analytical laboratory was maintained through systematic sample control procedures, including: 0 Sample receipt Q Sample log in 0 Sample storage .<; Q Sample archival or disposal The laboratory COC procedures were documented in the laboratory's quality assurance (QA) plan, which was provided as an attachment to the RFI workplan. <BBB) ^ COUWAK IICMCUATKM WOW OvfvumriMMcamwHQMuf > I C:WlRW20a7205RFI.DQCU9.JUN-9720Sl 4-1 IS? s EID090379 SEGTIONFOUR RCRftRelJ Investigation Results 4.1.1 RFI Data Quality Objectives The RFI data quality objectives (DQOs) were set based on RFI needs. The DQOs were stated in Section 3 and TabTeT of the QAPP in the RFI Work Plan. Quantitative DQOs were established for completeness, accuracy, and precision. Completeness was calculated as usable data as a percentage of all analytical data generated. Results for individual metals were qualified as unusable (flagged R) for project purposes in one or more samples. The loss of these individual results as a result of data validation and evaluation did not materially affect the evaluation of the Washington Works site and did not change the conclusions reached in this report. Eleven sample results were found to be unusable out of 3,732 total results generated, for a completeness of greater than 99%. This value exceeds the completeness goals established in the QAPP. Precision and accuracy goals established in the QAPP were adopted from the associated analytical methods. Precision and accuracy results were evaluated and qualifiers applied as necessary for samples designated for mil data validation. 4.1.2 RFI Analytical Protocol Deviations All analytical procedures used by the laboratory for this investigation were USEPA-approved procedures with the exception of the surfactant ammonium perfluorooctoanate (FC-143), for which an USEPA-approved method was not identified. The analytical procedures used for the majority of the analyses were according to Test Methods for Evaluating Solid Waste Physical/Chemical Methods (SW-846, December 1996). The remaining analyses with the exception ofFC-143 were conducted according to Methods for Chemical Analysis of Water and Wastes (USEPA 600/4-79-020, March 1988). The FC-143 analysis was perfomied according to a laboratory standard operating procedure (SOP) utilizing extraction, derivitization, and gas chromatograph (GC) electron capture detector (ECD) analysis. Laboratory analysis was primarily performed by the DuPont partner laboratory Lancaster Laboratories, Inc. (LLI), Lancaster, Pennsylvania, as specified in the QAPP. LLI is evaluated, via periodic on-site audits, on an ongoing basis by DuPont to assess performance and to generate confidence in data obtained from sample analysis. Deviations from planned sample analysis are described below. .s-s 4.1.2.1 FC-143 Analysis FC-143 analysis was performed for soil and first round groundwater samples by CH2M Hill (Quality Analytic), Montgomery, Alabama. Quality Analytic, however, ceased operation prior to second round groundwater sample collection. The FC-143 analytical SOP was subsequently provided to LLI and LLI performed all required analyses of second round groundwater samples. A comparison of first and second round groundwater analysis results for FC-143 showed that many, but not all, second round results for FC-143 were higher than first round results. DuPont is investigating possible differences in the FC-143 standard used by the different laboratories for calibration and spiking in an attempt to explain the generally higher FC-143 results found during second round groundwater analysis. A third round of groundwater samples were collected from selected wells to verify this discrepancy (see Appendix D). B6 ^ COBPOWTi RfiMCaAflON GROUP &^Wf witf Ita MCOMMMfGlwii C;\MARY\7205V7205RFI.D002&-JUN-99\7205\ 4-2 EID090380 SEGTIONFOUR ________BGBAHeMlntfesMBatton Bosuns In addition, FC-143 analysis at each laboratory generally gave poor or imprecise spike recoveries as discussed in Section 4.1.3, resulting in qualification of validated FC-143 results as estimated. Two groundwater results and an equipment blank were qualified as unusable as discussed below. 4.1.2.2 Encore Sampling Encore samplers were used to obtain and ship soil samples to the laboratory for methanol preservation according to USEPA Method 5035. Some sample weights were found upon methanol preservation to fall outside the recommended weight range of 4.5 to 5.5 grams. In all such cases the sample preparation and analysis was performed using the sample received at the laboratory and detection limits were adjusted accordingly. 4.1.3 RF! Data Usability Review and Data Validation All of the analytical data (100%) was reviewed by the laboratory prior to reporting the data and by the DuPont Corporate Remediation Group (CRG) Analytical Data Quality Management (ADQM) team upon receipt of the data. Any major or minor QA/QC deficiencies are noted in the narrative portion of the laboratory data packages. In addition, full data validation was conducted on 10% of the RFI samples, as stated in the RFI Work Plan QAPP. Soil and groundwater sample results were validated by Environmental Standards, Inc. (ESI), Valley Forge, Pennsylvania. ESI performed the validation using the National Functional Guidelines (for organic and inorganic compounds) modified for use in USEPA Region in. The validation reports prepared by ESI, each including an executive summary, are available for inspection upon request. Samples selected for validation represented data from all types of sampling conducted and parameter analyzed during the RFI. Laboratory generated Contract Laboratory Program (CLP)like data packages were selected for validation at random in order to 0 Evaluate approximately 10% of the total number of samples analyzed Q Preferentially select samples allowing validation of a more complete analytical list Q Minimize the number of data packages submitted for validation -- Q Allow complete data packages to be evaluated As stated in Section 4.1.1, validation of the sample results by ESI resulted in assessment of individual target compounds/analytes in one or more samples as unusable for project purposes. Results were judged by the validator to be unusable (flagged R) primarily due to very low spike recoveries associated with non-detect FC-143 results and significant negative blank contamination associated with non-detect results for cadmium. The affected cadmium results may be considered usable at an elevated reporting level; however, this was not deemed necessary by users of the data. <sssa ^ CORPOMTB lUMmMTIOM OHOUl* nifirtmfTTl.HfrfVimlftlMf fayMIHn.aiAfcBX? w<m&i-. Mmzr C:IMAR'A72(15W205RF1.00029.JUN-99>720S> 4-3 ^ GO g? S % EID090381 SEGTIONFOUR BORAHeld Investigation Results Additional qualifiers were applied to the data by the validator to reflect samples where values may be considered to be estimated or to exhibit a high or low bias, such as where batch or sample spike recoveries fell outside QC criteria, or associated blank samples indicated an outside source (incomplete equipment cleaning, shipping, storage) of sample contamination. . Qualifiers provided by the data validators as well as those as well as those assigned upon farther evaluation of analytical data were entered into DuPont's Corporate Environmental Database (CED) and are reflected in the tables and figures of this report. 4.2 SOIL INVESTIGATION The sections below present soil sampling results obtained from the RFI. All results have been summarized in Appendix A, The tables include comparisons with USEPA Region HI RBCs for industrial soil (or to a preliminary screening level for FC-143). Data results are also posted graphically on site maps. The soil investigation was designed to fill data gaps remaining after the VI. In some instances, (i.e., SWMU H-14, Burning Ground) the soil investigation focused on near-surface (i.e., 0-2 foot) soil quality. In the following section, some comparisons between the VI data and the RFI data are presented. 4.2.1 Background Soil Sampling Background soil samples were collected at ten locations near the upgradient perimeter of the property away from the main plant area (see Figure 3.1). Background soil samples were analyzed for the parameters listed in Table 4.1. Table 4.1 also presents a summary of background soil sample results. These summary concentrations were compared to SWMU area soil sample results to determine if the result exceeded background levels. Based on the comparison of individual SWMU area soil sample results with background concentrations, the following key results are noted: Q The majority of individual metal results were less man or equivalent to the respective background concentration. 0 FC-143 was present in several background, near-surface samples. This is attributed to deposition of airborne particulate originating from the Teflon process area. <ss ^ . COWauT<lIBM1K(Mr >bUn a^rt--tfJtalwcolMiaWamw ^WM HB UUq 37 WftftqtBK.OltaM* WHMU > US a CAMARy\7205l7Z05RFI.DOC\2a-JUN-99\720S\ 4-4 2 N1 00 o\ EID090382 SECTIONFOUR BCBflHein Investigation Results 4.2.2 SWMU A-3--Riverbank Landfill (RBL)and SWMU B-4--Anaerobic Digestion Ponds (ADP) Results for the ADP-and RBL are discussed together because the ADP is located within the RBL SWMU boundary. Samples collected within these two SWMU units were analyzed for the following organic parameters: methylene chloride (MeCl), Freon-113, PCE, TCE, and FC-143. All organic analytes were detected in the soil investigation in at least one soil sample. Several soil borings were advanced downgradient of the RBLLI seep area to determine the horizontal and vertical extent of methylene chloride impact. These locations were M04-SB02, M04-SB03; and N04-SB02. Figure 4.1 depicts the soil sample findings for this area. Mostly low levels ofMeCl were found in four soil samples at depths ranging from 2 to 14 feet BGS from boreholes M04-SB05 and N05-SB01 in the soil around the seep area. The highest concentration ofMeCl detected was from the 6- to 8-foot interval in M04-SB05 (320,000 ug/kg). This interval appears to be the only true hot spot found near the seep area because sampling intervals below and above display much lower concentrations (less than 700 ug/kg). Soil samples collected downgradient from M04SB05 did not contain detectable MeCl, indicating limited horizontal movement away from the seep area. MeCl was not detected in samples from any other location at the site. Freon-113 was detected in ten soil borings around the western section of the RBL/ADP. Figure 4.2 presents the results of analysis for Freon-113 in each of the sample locations. The Freon-113 soil concentrations ranged from nondetect to 9,700 ug/kg. In general, the Freon-113 was detected in subsurface soil samples (i.e., greater than 2 feet). These results confirm similar Freon-113 levels detected during the VI. Low concentrations of both PCE and TCE were detected in soil samples collected near the RBL/ADP SWMU areas. Figures 4.3 through 4.6 present the sample locations and results. PCE was detected at concentrations up to 3,800 ug/kg and TCE was detected at concentrations up to 8,800 ug/kg. In general, these constituents were detected in subsurface soils (i.e., greater than 2 feet) in a random pattern throughout the limits of the RBL/ADP. No specific source area was identified. However, the highest concentrations appear to occur near the western portion of theRBL. .--. FC-143 was detected in a number of soil samples collected in the RBL/ADP SWMU area. Figures 4.7 through 4.9 present the soil sample locations and results of me analyses for FC-143. FC-143 was detected at concentrations ranging from 18 to 48,000 ug/kg. The highest results are associated with the ADP area and occur in soil samples collected from the 8- to 12-foot depth range. These results confirm similar results collected during the VL Samples collected in the RBL and ADP were also analyzed for five inorganic analytes: arsenic, barium, cadmium, lead and nickel. The detected concentrations of these inorganic parameters were similar to the mean level found in the background samples (see Section 4.2.1, Background Soil Sampling). <vasi ^ cawvmn. mmmemiKw O^M Mtf fft* WC OtMMrt Omf I1WU>PbU(UM>I > 03 3 A <; CflMARY<7209720SRF1.0002JUN-9Sl720a 0 4-3 0 8 00 ^1 EID090383 SECTIONFOUR ROBAneM investigation Results 4.2.3 SWMU C-6 -- PolyacetalWaste Incinerator (PWI) Two soil samples, L08-SB02 and L09-SB02, were collected in the PWI and analyzed for chromium. The chromium results for these two samples were 10.8 and 9.6 mg/kg respectively. The chromium concentrations were equivalent to the background levels (4 to 120 mg/kg) at both locations. 4.2.4 SWMU H-14 -- Burning Ground (BG) Numerous soil samples were analyzed in the BG for two organic compounds: carbon tetrachloride (CT) and FC-143, which were detected during the VI in nearby groundwater samples. CT was detected at two locations at relatively low concentrations (180 to 840 pg/kg) within the BG area as indicated on Figure 4.10. FC-143 was also detected in several of the samples collected in the BG at low concentrations (10 to 140 y-g/kg). Figures 4.7 through 4.9 present the results of the analyses for FC-143. Samples collected in the BG SWMU were also analyzed for five inorganic parameters: arsenic, barium, cadmium, lead, and nickel. The concentrations of these inorganic parameters were similar to the levels found in background samples (see Section 4.2.1, Background Soil Sampling). 4.2.5 Soil Investigation Summary The RFI soil investigation's primary objective was to determine if constituents of interest identified during the VI were present in soils underlying or adjoining the RBL, ADP, PWI, and BG. In the RBLLI seep area, a more detailed investigation was conducted to determine the extent ofMeCl impact to soils. In addition, in order to assess qualitatively the level of observed impacts and their potential significance, all soil sample results were compared to USEPA Region III RBCs for industrial soil (USEPA Region m 1999) or to a preliminary health-based screening level for FC-143 (derived in Section 6.4.3). The soil investigation results are summarized as follows: Q Metal constituents detected in soil were comparable to background concentrations (see Table 4.1). Q PCE, TCE, and Freon-113 were detected throughout the RBL and ADP area soil, primarily in subsurface samples (depths greater than 2 feet). Concentrations were relatively low (typically 2,000 u,g/kg or less). The maximum concentration ofFreon-113 was 9,700 mg/kg at a depth of 10-12 feet. Q Extent ofMeCl impacts at me RBLLI seep area appear to be limited to a "hot spot" at about 8 to 10 feet BGS. 'asasa ^ coofofunflBxiwmoNMoup WMXI--WCOUMOKW > w w 4-6 C:lMARY\7205W205RF1.00029-JUN-99ff205< 0 0 s 00 00 EID090384 SECTIOHFOUR BCRflHeM investigation Kesults a The surfectant FC-143 was detected in soil throughout the RBL, ADP, and BG SWMU areas. The highest concentrations (up to 48,000 ug/kg) occurred in ADP area subsurface _ _ soils. Q None of the organic constituents detected in soil (i.e., PCE, TCE, MeCl, Freon-113, or FC-143) exceeded their respective RBCs (or preliminary screening level for FC-143). Further discussion of the soil investigation results is provided in Section 6, Screening-Level Risk Evaluation. 4.3 GROUNDWATER INVESTIGATION 4.3.1 Plantwide Groundwater Sampling Plantwide groundwater sampling was conducted during two separate monitoring events. The sampling events focused on existing and newly installed wells associated with the BG and RBL/ADP SWMUs. As per the VI results and the approved RFI workplan (DuPont 1997), groundwater was not investigated at the PWI. Table 4.1 lists the parameters that were analyzed at each specific SWMU. Following is a discussion that describes the findings for individual parameters. Results are summarized in Tables 4.2 to 4.6, and complete analytical results are shown in Appendices B and C. Methyiene Chloride (MeCI) All plant wells were sampled and analyzed for MeCI except for those located within the BG. MeCI was not detected in any of the groundwater samples collected during either round of sampling. This includes M04-MW02 and N04-MW02, two monitor wells situated between the RBLL1 seep area and the Ohio River. Carbon Tetrachloride (CT) Five wells within and in close proximity to the BG were sampled for CT. CT was detected in samples from two of the wells. Table 4.2 presents the results from both rounds of sampling. Figures 4.11 (Round 1) and 4.12 (Round 2) show the well locations and CT sampling results within fhe BG SWMU. Detected concentrations ranged from 1 to 16 ug/L. Tetrachloroethene (PCE) All plant wells included in the two rounds were sampled for PCE except for the five wells within the BG boundary. PCE was detected in several wells on the plant site. All detections are associated with the RBL/ADP SWMUs. Figures 4.13 and 4.14 show the results and locations where PCE was detected in groundwater. Table 4.3 lists the results for both rounds of groundwater sampling and demonstrates consistency between rounds. Observed concentrations ranged from 1 to 240 u.g/L. <SSSSl ^ c(MpofUTfiRcifiiATioM<Majp AlMblMMMMn a^MMnwWca--MjOwf 9^IUarfus.lhM(9TT > w C:UMRW20a720SRFI.DOQ29-JUN-9mr20 4-7 ffi 0 0 s 00 ^0 EID090385 SECTIBNFOUR RCRAHeld invesiloaUon Results Trichloroethene (TCE) Wells that were included in the PCE sampling were also analyzed for TCE. Similar to PCE, TCE was detected-ifl-several wells on the plant site. Figures 4.15 and 4.16 show the results and well locations where TCE was detected. Like the PCE detections, TCE in groundwater occurs near the RBL/ADP SWMUs. Table 4.4 tabulates the results of the sample analyses for both groundwater sampling rounds. Observed concentrations ranged from 1 to 800 ug/L. Freon-113 Freon-113 was analyzed for in samples associated with the RBL/ADP SWMUs. In both rounds, Freon-113 was detected in twelve of the wells sampled. Table 4.5 tabulates the results of the sample analyses. Well locations and sample results are presented in Figures 4.17 and 4.18. Observed concentrations ranged from non-detect to 7,100 ug/L. FC-143 All plant wells were sampled for FC-143. Figures 4.19 and 4.20 depict the well locations and results for FC-143 detections. Table 4.6 presents the analytical results of the FC-143 sampling for both rounds. Observed concentrations ranged from 0.1 to 13,600 ug/L. Concentrations were below 40 ug/L in 28 of the 37 wells sampled; in the other 9 wells, maximum concentrations ranged from 380 to 13,600 ug/L. The highest concentrations were observed in monitoring wells P04-MW02 and R04-MW02, near the ADP area. 4.3.2 Groundwater Investigation Summary Groundwater sample results were compared to MCLs for drinking water or a health-based screening level for FC-143 (see Tables 4.2 to 4.6). Several exceedances of the screening criteria for organic compounds occur mainly within the RBL/ADP SWMUs. m light of these findings, a thorough analysis of the site groundwater flow regime and the significant results of that analysis are discussed in Section 5. Several total and dissolved inorganic parameters, specifically, barium, cadmium, lead, and nickel exceeded MCLs (see Appendices B and C). These exceedances occurred in samples taken at SWMU areas and in (he background samples taken away from the manufacturing area. Based on the background levels, metals in groundwater are concluded to be naturally occurring and " unrelated to SWMU releases. The groundwater investigation results indicate: Q The seep collection and treatment system is effective at preventing off-site migration of seeps at RBLL1. Q The BG is not a significant source of constituents in the groundwater. Q The constituents of concern detected in groundwater are coming from the RBL/ADP SWMUs. ^ iSESS cvwoMmuueoumauwww OuCMmfnrWCObmiMrfOiWf BriH MB n^ rftfn| ir MirinfK.MlHn 1MW402T > ^ C:>MARYV20a7205WI.D0029.XIN4720a 4-8 S SO 0 EID090386 SEGTIONFOUR RCRAField Investigate Results Q Metals are naturally occurring and do not. appear to be SWMU-related constituents of concern. issna ^ CORPOIUHI fOHnONOAOUP *IJUiMMMwOT OlArtftrf n we ObMaitfOnw > ^ C:'MARW20St7205RFI.D0029-JUN-Ba\7205\ 4-9 0 S SO BID090387 5.1 INTRODUCTION In accordance witfrthe September 24,1997, DuPont Washington Works RCRA Facility Investigation Plan, Section 3.1.2, a mathematical model ofgroundwater flow at the site was constructed. A preliminary model was constructed in 1998, prior to the initiation of the RFI sampling activities, to assist in developing a more comprehensive list of field data needs. The results of the preliminary modeling were submitted to the USEPA Region ffl on August 18, 1998, in a letter report, "RFI Work Plan: Groundwater Model Update Report." The preliminary model has been refined based on data collected during the RFI, and the results presented herein. Prior to beginning the mathematical modeling, new hydrogeologic data collected during the RFI were reviewed to confirm the site conceptual model. Since the model construction is based on the conceptual model, parameters such as river stage and hydraulic conductivity were refined in the mathematical model based on new information. The model was then calibrated to a recent data set, February 1,1999, which included groundwater elevation data from a sufficient number of new and existing monitoring wells. After the model was calibrated, model parameters were independently increased and decreased relative to the value obtained during calibration to determine to which parameters the model is most sensitive. This helps to determine the degree of model uncertainty. The model was also verified against historic data sets. Then the calibrated model was used develop predictive runs under different pumping regimes. 5.2 CONCEPTUAL HYDROGEOLOGIC MODEL As part of the hydrogeologic model development, all available hydrogeologic data for the Site were reviewed. All site-specific boning logs, groundwater elevation data, water supply well data, and regional hydrogeologic data were compiled and reviewed to determine the number of model layers, groundwater flow, boundary conditions, and the global water balance for the area to be modeled. Previous studies show that the site is underlain by two primary geologic units: river terrace deposits and bedrock. The Pleistocene-age river terrace deposits are a fining upward sequence consisting of coarse sand and gravel deposits at the bottom grading up to finer sands, silts, and clays at the top. There are overbank deposits consisting of silt and clay along the Ohio River banks that are above the water-table aquifer. Fine-grained sediments may continue into the river bed in some areas due to bank slumping and low energy in the river, which creates a depositional environment for fines. In other areas of the river where energy is high, fines are eroded and coarser-grained sediments predominate (see cross sections in Figures 2.5A-2.5F). The alluvium is approximately 100 feet thick. Over the operating portion of the site, the contact between the alluvial deposits and the consolidated bedrock is relatively flat, at an elevation of approximately 530 feet above MSL. The bedrock is composed of Permian-age shale and sandstone of the Washington Formation which is part of the Dunkard Group. The bedrock permeability is very low compared to the overlying alluvial river terrace deposits (Schultz 1984). Just south of State Road 892, the Ohio River terrace ends and the bedrock outcrops at the surface. <SSQS> ^^ CCAPOAATC WUEOWWH OMW > CO g 0 C:IMWW21)a720SRFI.DOC\JUN.99ff20a 5-1 {3 v0 M EID090388 SECTIONFIVE Washington Works GroiindwateFMoileS Groundwater is encountered in <he alluvium at the site at elevations ranging from approximately 570 to 554 feet MSL, with groundwater flow toward the process water supply wells at the site. The water level in the Ohio River adjacent to the site averages 582 feet MSL. Groundwater is recharged from rainfall, which averages around 35 inches a year (National Climatic Data Center and United States Geological Survey (USGS)), and river water infiltration. Since the bedrock permeability is much lower than the alluvium, there is not significant groundwater interaction between the bedrock and the alluvium. Surface water runofffrom bedrock outcrop areas to the south is assumed to be carded away via surface water drainage ditches and therefore does not recharge groundwater. 5.3 GROUNDWATER FLOW MODEL DEVELOPMENT A groundwater flow model of the site was constructed based on available data and the conceptual hydrogeologic model described above. The USGS model MODFLOW (McDonald and Harbaugh, 1988) was used to calculate groundwater elevations. MODFLOW is a threedimensional, finite-difference groundwater flow model. The model MODFLOW was used because it is well documented and widely accepted by regulatory agencies and industry. The model pre- and post-processor Model Cad for Windows (Geraghty & Miller) was used to design the model grid, facilitate the building of input files for MODFLOW, and view the MODFLOW output files. The model was set up as a one-layer, two-dimensional model. The model domain includes the following area (Figure 5.1 outlines the model domain on a USGS topographic map): Q North to South - North from the middle of the Ohio River Channel, and south to just below GE. The north to south domain totals 8,800 feet. Q East to West - East where the terrace deposits end at the valley wall, and west to the middle of the Ohio River channel. The east to west domain totals 15,500 feet. The model was constructed by gridding the area into square regions called cells. The grid spacing or cell size is 50 feet by 50 feet over the entire modei'domain (see Figure 5.2). The cells were then grouped into zones based on parameters such as hydraulic conductivity and recharge. The areas of bedrock outcrop south of State Road 892 and northwest of the Ohio River were set as no-flow boundaries. No-flow boundary conditions are applied to cells that are outside of the model's computational domain. A recharge rate of 11 inches a year was applied over the active flow cells in the model domain. Recharge was estimated to be about 1/3 of me annual rainfall of approximately 35 inches a year. Increased recharge along the bedrock outcrop south of the site was not simulated due to the presence of drainage ditches along State Road 892 that cany away runofffrom the bedrock outcrop and prevent it from infiltrating into groundwater. The Ohio River was modeled as a river with a stage of 584 feet MSL and a bottom of 553 feet MSL. River stage was modeled approximately two feet higher than average because of greater than average rainfall in February 1999 which caused a rise in river stage. The model-calibrated riverbed conductance was low. The latter is reasonable based on the presence ofthff fine-grained 4BB6 ^ CORPORATE FUMeoiMONMOUP 4nWMKtaAnan OAM<rf IM MAC OMMlrfOlww likrMXKi.faMqir > C;lMARYW2<ia7205RFI.DOC\30-.)UN-9W205\ 5-2 2 s s EID090389 SECTIONFIVE Washington WorlffiCroundwaterModel sediments which deposit along the low-energy reaches of the river found along much of the site boundary and along GB boundary. The bottom of the one-layer model was assigned an elevation of 525 feet MSL to approximate the bottom of the alluvial deposits. Figure 5.3 shows the location of the bomatary conditions, including no-flow cells and river cells. 5.4 MODEL CAUBRATION Once the model was constructed, it was calibrated to data collected from the site on February 1, 1999. This included extraction rate data ftom the site production wells and groundwater elevation data from 44 observation wells at the site. Elevations and.pumping rates from a specific day were used rather than averages since pumping rates vary over time. Pumping rates can fluctuate daily in response to production needs for water and well maintenance issues. Since the fall of 1998, pumping rates have been monitored continuously, but in most cases flow meters record flow for a group of wells (e.g. DuPont-Lubeck Well Field, Blennerhassett Island, East Well Field, etc.) rather than individual wells. DuPont also obtained a June 1996 groundwater elevation map from GE, which borders the site to the southwest This offsite information, including estimated groundwater extraction rates, was also included in me model setup. Values for hydraulic conductivity and riverbed conductance were initially estimated based on grain size and hydraulic properties estimated from production well performance. The hydraulic conductivity and riverbed conductance were then varied independently to obtain a reasonable match between the model head and the target or measured heads. Recharge was not varied, as it was only 16% of the water into the model and some variation would not have significant impact. The hydraulic conductivity for the site in the calibrated model is 250 feet per day, with a hydraulic conductivity of 900 feet per day in the area of the DuPont-Lubeck Well Field, which coincides with a coarsening of the alluvium in that area (see cross sections in Figures 2.5A-2.5F). The calibrated hydraulic conductivity in the vicinity of the Ohio River was slightly less, at 200 feet per day. Figure 5.4 shows the location of me three different conductivity zones. Riverbed conductance is higher in me vicinity of Blennerhassett bland than in the rest of the river, but both are estimated by the model to be low, 13.1 feet2 per day (ft ^d) and 2.3 ft Vd, respectively. The island is just off the cut bank or higher energy area of the Ohio River where coarser sediments are deposited. Riverbed conductance was calibrated at a somewhat lower value, 1.2 ft Vd, along the downstream portion of the site and along GE. This lower conductance coincides with the lower energy area of the Ohio River or fill bank, where finer sediments are deposited. The groundwater elevation contours calculated by the model are shown on Figure 5.5, along with the residuals or me difference in the model heads and the target heads. To evaluate the difference between the target heads and the model heads, a calibration statistics program, CALSTATS (Geraghty & Miller, 1993), was used. CALSTATS calculates the range in heads, residual mean, residual standard deviation, and other statistical parameters, for the overall model. The residual standard deviation for the calibrated flow model is 1.6 feet. The observed range in heads (15.6 feet) and the residual standard deviation vary by 10.3 % of the total change in head across the model, indicating a reasonably good calibration for the model. In addition, target heads were plotted against model heads, and the resulting scatter plot shows that most of the ^ CORPORATE MfcKwnoNmoup *|AK*W*M--M ItW MH PUn IdUkq 27 > M <- a CAMAf)W205V205RFI.DOC\30-JUN-99\7205\ 3--3 s ^ EID090390 SEOTIONFIVB Washington Works Groundwater Model residuals fall along a line of perfect fit (i.e., where the modeled head would exactly match the observed head). While scatter is observed along the line of best fit, the model shows little bias to modeling too high or too low. The CALSTATS results and the scatter plot for the calibrated model are included as Table 5.1 and Figure 5.6. 5.5 SENSITIVITY ANALYSIS Sensitivity analyses were conducted using the calibrated flow model to determine the parameters that are most important in the model. Sensitivity analysis helps to quantify the degree of uncertainty in the model. Values for recharge, conductivity, riverbed conductance, river stage, and pumping were independently increased and decreased relative to the values obtained during calibration. The effect of increasing or decreasing a parameter was evaluated by comparing the best fit line for a data set to the perfect fit line (see Figure 5.7) and by reviewing the statistics provided by CALSTATS (see Table 5.2). In all cases the groundwater contours and the flow regime were very similar to the calibrated model and there was very similar capture. The model seems to be most sensitive to conductivity and pumping rate. Conductivity is reasonably estimated in the model based on grain size and aquifer characteristics determined from the pumping wells. Decreasing the conductivity or increasing pumping increased the influence of the pumping wells. When conductivity was increased or pumping decreased, the flow regime and capture zone were very similar to the calibrated scenario as noted above. The model is somewhat sensitive to riverbed conductance, river stage, and recharge. Riverbed conductance is a parameter that cannot be measured, only calibrated to. River stage was already modeled at a high, and it is unlikely that the stage would be two feet higher for any extended time, so the river stage was not increased for me sensitivity analysis. Lowering the river stage increased the influence of the pumping wells. Recharge is unlikely to be as high as 47% of the annual ramfall (16 inches per year = 47% of annual rainfall), and lower recharge enhanced the groundwater control provided by pumping (see Fig. 5-7). Two additional data sets (piezometric elevations and estimated pumping rates) were available to verify tile calibrated model. The pumping data and the observed heads from November 1,1997, and November 9,1998, were modeled using the more usual river stage of 582 feet. In both cases all the model heads fell along a line parallel to me line of perfect fit, but were about 6 feet-lower man observed heads (see Figure 5.8). The discrepancy could be related to input values for river stage, conductivity, conductance, recharge, or pumping rates. Of these, the lower river stage was already accounted for, and conductivity and conductance should not vary seasonally. Rainfall in November 1997 and 1998 was likely lower than rainfall in the exceptionally wet February 1999, and lowering recharge would not help raise the model heads, even though there may be seasonal variations in ramfall that are not accounted for in the steady state model. Therefore, the most likely reason for the discrepancy is pumping. Pumping rates can vary greatly on a daily basis since they are process driven. A 20 % lowering of pumping rates shifted the November 1,1997, and November 9,1998, modeled heads up to levels closer to the observed heads, as shown on Figure 5.8. Due to the aforementioned variability in pumping rates, and the fact that individual wells do not have flow meters, a 20 % change from the rate estimated for one day is not 4BB> ^ caimuniumunoNiiiwup mj nf nr WCOteMrt Omif torMflr-ftlMn,a7 wiMHtfoH.iM--ir IBMOOCW CAMARW205l7205RF1.00C\29.JUN.9720a 5-4 EID090391 SECTIONFIVB Washington Worfcs Srounifwager Moitel unreasonable, given how much the rates can fluctuate and how they are recorded in groups, rather than individually, in some cases. 5.6 CONCLUSION OF GROUNDWATER MODELING After the model was calibrated, it was used to simulate various pumping scenarios using the site's existing production wells with the objective of maintaining hydraulic control of groundwater on the site while decreasing overall pumping. Contour maps depicting groundwater elevations and flow lines for various pumping scenarios were constructed. These maps illustrated the area of groundwater capture for each scenario based on flow line convergence to recovery wells. Flow lines were calculated using MODPATH (Pollack 1994). The model shows that lowering February 1999 pumping rates by as much as 65% would still result in hydraulic control of groundwater at the site. The pumping distribution would have to be changed to approximately 660 gpm for the Ranney well, 500 gpm for the DuPont-Lubeck wells, 290 gpm for me East Well Field wells, and no pumping on Blennerhassett Island. Figure 5.9 illustrates the groundwater elevations and flow lines at these pumping rates. The conclusion therefore is that the well pumping is containing SWMU-impacted groundwater and would continue to do so even with a significant reduction in pumping rates. The sensitivity results also indicate that groundwater is being contained even accounting for the uncertainty of the model input parameters, i.e., even if the hydraulic parameters input to the model are different from their true values, the sensitivity analysis results indicates that capture of SWMU-impacted groundwater is being maintained. 5.7 MODEL LIMITATIONS Since this is a steady-state model, it simulates an average site condition rather than a fluctuating one. It cannot simulate me short-term changes in pumping rates, or seasonal fluctuations in river stage and recharge rates. The boundary conditions to the south ofGE are uncertain, and GE water levels are based on a June 18-19,1996, groundwater elevation map with pumping rates estimated based on these water levels. However, for the purpose of demonstrating current capture and capture under reduced pumping, these uncertainties do not change the conclusion that the pumping is containing the SWMU-impacted groundwater at the site. 1----6 ^ CORKIWX MhCOUIlCM OMOUP MMIMWwa DiAntMJTtoWlcahMMrfdHW innoiu.l--iir C:>MARY\720Sl7205WI.OOC\29-JUN-99\7205\ 5-5 EID090392 6.1 OBJECTIVES AND APPROACH The overall objediwofthis risk evaluation is to determine whether identified releases from the SWMUs are a potential concern for human health or the environment and whether further evaluation or action is warranted. In the screening-level health risk evaluation, concentrations of constituents detected in soil and groundwater were compared to generic health-protective screening levels for soil and groundwater, in order to identify constituents and exposure pathways of potential concern. The ecological evaluation focused on characterizing the habitat within the RFI study area and identifying whether complete exposure pathways exist between SWMU releases and significant ecological resources or receptors. This approach allows identification of the constituents and exposure routes of concern early in the RFI/CMS process, and avoids expending effort on minor constituents and exposure routes that do not influence overall risk (USEPA Region III, 1993). The risk evaluation has been prepared consistent with the screening-level approaches outlined in the following documents: Q RCRA Facility Investigation Plan, DuPont Washington Works (DuPont, 1997). D RCRA Facility Investigation Requirements (included as Attachment D to the RCRA Facility Investigation Plan). Q USEPA Region ffl Technical Guidance Manual "Selecting Exposure Routes and Contaminants of Concern by Risk-Based Screening" (USEPA Region III, 1993). Q USEPA Region ffl Risk-Based Concentration Table (USEPA Region in, 1999). Q USEPA guidance for ecological risk assessment (USEPA 1997; 1998a; 1998b). In keeping with the above guidance documents, the risk evaluation includes: Q Description of on-site and adjacent land use (Section 6.2). 5f- Q Evaluation of data used in risk screening (Section 6.3). Q Screening-level health risk evaluation, in which analytical data were compared to generic health-based screening levels for soil, to drinking water criteria for groundwater, or to background levels (Section 6.4). Q Identification of constituents and exposure pathways of concern screening step (Section 6.5). Q Ecological exposure evaluation (Section 6.6). Q Summary and conclusions (Section 6.7). <ssss& ^ COflroXTtHaKBIAnoHOBOW Ol^HMU^nuWCOImMttMuf tatar Ml nua, IMtftq ir c-.wwRwwsnosswi.oocsso^w-wisaa 6-1 EID090393 SEGTIONSIX Screening level Risk Evaluation 6.2 SITE DESCRIPTION AND LAND USE This section provides an overview of land use at the Washington Works site and identifies potential human aad-ecological receptors. Additional information on current and future land use is provided in Attachment 1, Land Use Report 6.2.1 On-Site and Adjacent Land Use The Washington Works facility has been the site of ongoing industrial activities since the initial plant was first constructed in 1948. It occupies 1,200 acres, extending about a mile along the Ohio River seven miles west ofParkersburg, WV. Most of the facility is developed for manufacturing purposes and is covered with paving, rail tracks, and buildings. Open areas include lawns, mowed fields, and a few areas of natural growth along portions of the riverbank. The developed portion of the property is fenced, and access is rigorously controlled by a security system. The riverbank itself lies outside me security fence, but is regularly patrolled. The riverbank adjacent to the facility is relatively inaccessible, due to its location and the regular security patrols, and there is little to attract casual visitors to the river's edge. Adjacent land use is a mix of industrial, commercial, agricultural, residential, recreational, and open space. Adjacent industrial or commercial properties include GE Plastics and two warehouses to the west. Nearby residential areas include the unincorporated town of Washington, whose eastern extent is adjacent to the DuPont property, and individual homes and subdivisions within about a mile of the property to the east, south, and west. Figure 2.2 show the Washington Works site and adjacent land use. The Washington Works facility will continue to be used for industrial purposes in the future. Likewise, adjacent land use is expected to remain a mix of industrial, residential, and other uses. Land use issues are addressed in more detail in Attachment 1, Land Use Report. 6.2.2 Groundwater Uses The alluvial terrace unconfined aquifer is the principal regional aquifer and is used locally for industrial, municipal, and rural water supplies. Depth to groundwater is approximately 6Q,to 70 feet in the main plant area, and the saturated zone is about 30 to 40 feet deep, extending to bedrock at roughly 100 feet BGS. As indicated in previous sections of this report, DuPont Washington Works operates several production well fields on the plant property that provide industrial process water and potable water to the plant (potable water is provided by Wells 331 (A008, PW01), 332 (AQ09-PW01), and 336 (AM07-PW01), in the East Well Field). Off-site well fields in the downstream direction include eleven industrial and five potable water wells on the GE Plastics site located just to the west of Washington Works and the Lubeck Public Service District (PSD) well field located about 2.3 miles south (downriver) of the plant. The Lubeck PSD provides water to nearly 99 % of the population in this portion of Wood County (Lubeck PSD, 1999). Other private wells or small community wells of unknown status were identified during a well search, but they are suspected of being inactive (see Section 4.3 of Attachment 1, Location of Wellhead Protection'Areas and Drinking Water Wells). - 4BB) ^ COATORATE RGUfiOAnOM ORCXJP OkArtw ffl HiCOtoMMrfOMf blU<FU>.KlUI IMlMBM^&bwm M--aBatf 3 C.1MARW20S\7205RFI.DOC\29-JUN.99\720a 6-2 2 M \0 00 EID090395 SECTIONSDC Screening level BIsR EvaiuaUon As discussed in Section 5, pumping of the Washington Works well fields controls groundwater flow, so that groundwater affected by SWMU releases is contained on-site. 6.2.3 Surface Water Surface water of the Ohio River provides water to the cities ofParkersburg, West Virginia, and Belpre, Ohio, about seven miles upstream of the Washington Works facility. There are-no permanent streams or surface water bodies on the main plant area at Washington Works. Precipitation in the main plant area is directed toward drains and storm sewers, which ultimately discharge to the Ohio River. Two drainage swales that convey surface nmoffto the Ohio River during rainy weather are located on the property, one in the facility's southwest comer and the other on the extreme eastern (upgradient) end of the property. The former BG and PWT have been excavated, backfilled, and resurfaced, so there are no surface water impacts from these SWMUs. The slopes of the RBL/ADP above the Ohio River are heavily vegetated, and the SWMUs have been covered with clean fill, so surface water impacts via surface runoff from these SWMUs are considered negligible. As indicated in the previous sections, SWMU-impacted groundwater does not discharge to surface water because of production well pumping. 6.2.4 Ecological Setting The Washington Works site itself is largely developed and used for manufacturing activities, with manicured lawns, mowed fields, and a few areas of natural growth along portions of the river bank. These areas provide a narrow and intermittent terrestrial habitat for a variety of birds, small mammals, and other animals. The upper terraces upstream and downstream from the plant are kept in grassland with some small areas of trees and brush. A small chestnut grove is being developed by the facility's Wildlife Habitat Enhancement Program, in conjunction with the American Chestnut Foundation. There are no known records of any federal or state listed species in the vicinity of the Washington Works Site (West Virginia Division of Natural Resources [WVDNR], 1999). In addition, no wetlands or critical tecrestrial habitat were identified at the Washington Works facility during field observations conducted at the site. Section 6.6, Ecological Exposure Evaluation, provides additional site-specific information about ecological resources and exposures at the site. <SOt> ^ CCMKMATE (UMfOIATMM BMOUP ttuMwwwuma OAlirri AWCDtaiMntfOnw > w C:\MARW205l720SWI.OOCe9-JUN-9720a 6-3 0ffi 0 0 M 0 ^0 EID090396 SECTIOHSIX_____________ScreenliiB level Risk Bfahiation 6.3 DATA AND MEDIA EVALUATED Soil and groundwater analytical data collected during the RFI were discussed in Sections 4.2 and 4.3. No quality assurance or quality control issues were identified that would affect data usability in risk assessment. Tables 6.1 through 6.4 show the soil data included in the risk evaluation. These data were from samples collected between 0 and 20 feet BGS at the BG and RBL/ADP units. The depth of 20 feet is considered a conservative estimate of depth of excavation for future construction or utility work. Two soil intervals were evaluated: 0 to 2 feet (surface soil) and 2 to 20 feet (subsurface soil). Table 6.5 shows the groundwater data included in the risk evaluation. These data were from water quality samples collected at the five production wells sampled during the RFI investigation: K16-PW01, L17-PW01, AM07-PW01, V05-PW01, andL04-PW01. Water from these wells is used to supply process water to the manufacturing area, and water from Wells AM07-PW01 (336) provides potable water to the plant. Therefore, groundwater drawn from these wells is representative of the exposure medium to which humans are or could be exposed. 6.4 SCREENING-LEVEL HEALTH RISK EVALUATION The purpose of the screening-level health risk evaluation is to identify the constituents and exposure pathways that may be a concern for human health and that may warrant further evaluation or action. Constituents whose maximum concentrations do not exceed healthprotective screening levels and environmental media that have no constituents exceeding screening levels are concluded to pose no concern for human health and can be eliminated from further evaluation. Potential exposure to multiple chemicals and multiple media also is considered in the risk evaluation, in order to strengthen conclusions drawn from the risk-based screen. 6.4.1 Potential Human Receptors : Human exposure to hazardous constituents released from the SWMUs is minimal or non existent, because they have been removed and regraded or paved (BG, PWI, ADP) or coveted and vegetated (RBL). However, for the risk evaluation it was assumed that potential on-site human receptors include site workers, occasional trespassers along the riverbank, and construction workers performing excavation work. Of these, the on-site worker is the most exposed individual, because he or she is assumed to be present on a daily basis for the duration of his/her career. Therefore, evaluating presumed on-site worker exposure to soil at the SWMUs is protective of construction workers and trespassers, whose exposure would be short-term and intermittent. Likewise, workers are the only receptors who are exposed to production well water. Construction workers would not be exposed to groundwater during excavation because the water table is about 60 feet BGS. ^ COWOfWTB MUEOWWH OAOUP a^wnu^ Truvrrnmnv^Oivif toyMIPtaMRwqir WiNngwi^CMw WVMOV C:yaARVW205l7205RFI.OOC\29-JUN-flm720K 6-4 EID090397 SECTIONSIX Screening le^l BIsR BraHiatton 6.4.2 Screening Levels Used in the Evaluation Soil data were compared to the following screening levels: Q USEPA Regionffl RBCs for industrial soil (soil ingesdon pathway) (USEPA Region III, 1999). The RBCs are based on a target excess cancer risk of 10 (1 in 1 million) and a noncancer hazard quotient (HQ) of one. These RBCs represent chemical concentrations in soil that would be expected to pose no adverse impacts to health under the exposure conditions evaluated. Industrial soil RBCs were used because the current and future use of the property is industrial (Section 6.2.1 and Attachment 1, Land Use Report). Q A screening level for lead in industrial soil of 1000 mg/kg. This level is a conservative (low) estimate for industrial soil screening purposes, because it is below typical screening levels calculated using USEPA's Adult Lead Exposure Model (1,200 to 1,800 mg/kg, using default parameters) (USEPA l996a). Q Federal MCLs for drinking water or the federal action level for lead in tap water. Q USEPA Region ffl RBCs for tap water (in the absence of an MCL) (USEPA Region ffl, 1999). Q Preliminary screening levels for PC-143 in soil and groundwater (see Section 6.4.3). Certain potential exposure pathways are not included in the derivation of the screening levels, namely: Q Inhalation: The inhalation pathway is not included in the derivation of the USEPA soil screening levels used in this evaluation. Nor are there USEPA-established "soil-to-air" screening levels for an industrial scenario. However, neglecting the inhalation pathway is not expected to significantly affect the results of the risk screening for the following reasons. -- First, inhalation of non-volatile constituents (such as metals or FC-143) that are adhered to soil particulate matter usually does not contribute significantly to overall risk because air emissions from wind erosion are, on an annual average basis, relatively low. This is represented in USEPA's default Particulate Emission Factor (PEF) of 1.32 x ICT n^/kg soil (USEPA 1996b). When applied in the denominator of an equation to estimate air concentrations of particulate matter, the resulting air particulate matter concentrations are negligible and usually do not contribute to overall risk. -- Secondly, volatile constituents, such as methylene chloride or trichloroethylene, were relatively infrequently detected in soil (see Tables 6.1 through 6.4), and would not be expected to contribute to a significant inhalation hazard. Therefore, the industrial soil RBCs are considered sufficiently conservative (protective) for the screening-level risk evaluation. If constituent concentrations in soil exceed the RBCs, the inhalation pathway may warrant consideration in the future. ^ Kd fir W OtelMHrf OfK WrW>W CaMARY\720W5WI.OOCU9slUN.9a\720a 6-5 B 0 0 0 UJ 0 EID090398 SEGTIONSIX Screening level RISKEvaluation Q Dermal absorption: The dermal absorption exposure route is not included in the derivation of the USEPA soil RBCs used in this evaluation. Although this adds a small uncertainty to the screening levels, it will not significantly affect the results of the screening;Hi cases where constituent concentrations in soil exceed RBCs, dermal absorption may warrant further consideration in the future. Q Migration to groundwater: Soil screening levels for protection of groundwater used as drinking water were not included in the risk screening evaluation because groundwater data were compared directly to drinking water criteria. 6.4.3 Derivation of Preliminary Screening Levels for FC-143 USEPA-established screening levels are not available for FC-143. Therefore, preliminary screening levels analogous to Region ffl RBCs for soil and groundwater were derived from a health-based Community Exposure Guideline (CEG) of 0.0003 mg/m3air (Haskell Laboratory 1991). The CEG was developed by Haskell Laboratory to be protective of public exposure via the inhalation pathway. The CEG was derived from the DuPont Allowable Exposure Level (AEL) for workers of 0.01 mg/m3. Both the AEL and the CEG are health-protective of the exposure conditions to which they apply. For example, the AEL for workers is 100 times lower than a No Observed Effect Level in a laboratory animal inhalation study and is 1,000 times lower than a Marginal Effect Level in a laboratory animal feeding study (Haskell Laboratory 1991). Therefore, the AEL is considered to be a safe level for workers potentially exposed for eight hours/day. To derive a level protective of sensitive subpopulations (such as infants and the elderly) and to account for a 24-hour/day exposure time, the AEL was reduced further by a safety factor often to account for the presence of sensitive subpopulations in the community and again by a safety factor of three to account for a 24-hour/day exposure time, resulting in fee CEG of 0.0003 mg/m3. Therefore, the CEG is considered protective of general public exposures that could include sensitive subpopulations, exposed 24 hours/day. - Exposure to the CEG of 0.0003 mg/m3would result in an allowable daily intake of 0.006 , mg/day, assuming an inhalation rate of 20 nrVday(USEPA Region DI default residential inhalation rate). From this allowable intake, preliminary screening levels for soil and groundwater can be calculated using USEPA default exposure assumptions for industrial soil ingestion and residential groundwater ingestion. Table 6.6 shows the calculation of preliminary screening levels for FC-143 in industrial soil (120 mg/kg) and for groundwater used as drinking water (0.003 mg/L). These preliminary screening levels were used in evaluating site soil and production well water data for FC-143. & o CORKMtAT fWWSAWM WWW OJWM^DwWCa ;."s& > &Q hv-t C:1MARVV205\720SRF1.00029-.IUN-9Stf20a 6-6 Q 0 0 OJ s EID090399 SEGTIONSIX Screening level Risk Evaluation 6.4.4 Results of Risk-Based Screening for Soil Tables 6.1 through 6.4 show the sample analytical results for constituents detected in soil and groundwater andjnclude the SLs for comparison. Table 6.7 summarizes the results of the risk- based screening for soil. Table 6.7 shows that maximum observed concentrations of all constituents at all SWMUs and soil intervals were well below their respective screening levels, with the exception of arsenic (which is present at concentrations comparable to background levels). Therefore, it is concluded that constituents in soil do not pose a health concern for workers via the soil ingestion pathway. Potential exposure via other routes (e.g., dermal absorption or inhalation) and possible additive effects of multiple noncarcinogens are also not a concern. Maximum observed concentrations of all site-related constituents were lower than screening levels by factors often to one million, except for FC-143 and methylene chloride in the 2- to-20-foot interval at the RBL/ADP, where maximum concentrations of these two constituents were lower than their respective screening levels by a factor of about 2.4. Because maximum observed concentrations of site-related constituents are well below conservative health-protective screening levels, it is concluded that constituents in soil do not pose a health concern for workers or transient receptors. 6.4.5 Risk Screening for Production Well Water Table 6.5 compares sample analytical results from production well samples to MCLsor other health-based screening levels for drinking water. Table 6.8 summarizes the risk-based screen for production well water. In well AM07-PW01, which supplies potable water for the plant, maximum concentrations of all constituents were below their respective drinking water criteria. To confirm this conclusion, a third round of analysis for FC-143 was conducted in May, 1999 (see Appendix D). Therefore, no unacceptable health risk would be associated with the observed concentrations in the potable water well. - hi production wells providing industrial process water, maximum concentrations of all constituents were also below health-based criteria for drinking water, with the exception ofTCEin production well V05-PW01 and FC-143 in production wells K16-PW01, V05-PW01, and L04-PW01. Specifically, the maximum concentration of TCE (22 micrograms per liter (ug/L)) exceeded the MCL of 5 ug/L, and the maximum concentration of FC-143 (16.2 ug/L) exceeded its preliminary screening level for drinking water of 3 ug/L (Table 6.8). For both constituents, maximum concentrations exceeded their respective drinking water criteria by factors of four to five. Because water from these wells is not used for drinking, but rather for industrial processes such as non-contact cooling water or fire water where exposure is nonexistent or intermittent, it was concluded that the exceedances of the drinking water criteria by relatively small factors is not likely to pose health concern for workers, who may be exposed to process water. <BB ^ COIWOfurKRaKOMIONOROU^ Oi^lMv^nmWCOtmuntqmv toyMnuftAk4 > us y csiwwipawsaswicooaa-wH-wsoK 6-7 o (^ 0 L>-> EID090400 SEGTIONSIX Screening Level Risk EvaEuaiion 6.5 SUMMARY OF CONSTITUENTS AND PATHWAYS OF CONCERN (HUMANHEALTH) All constituents in^all media evaluated were below health-protective criteria, with the exception ofTCE and FC-143, whose maximum concentrations in industrial process well water exceeded drinking water criteria by factors of four to five (see Appendices B and C). However, average concentrations in process water at the point of use (which is a mixture of water from several production wells) will be lower than maximum concentrations detected in one well. Therefore, these exceedances are not considered a concern for worker health under exposure conditions typical for industrial process water. As demonstrated in Section 5, SWMU-unpacted groundwater is contained on-site by production well pumping and does not migrate off-site or to surface water. In summary, the identified releases from the SWMUs are not a concern for human health. Siterelated constituent concentrations in soil (0 to 20 feet) did not exceed screening levels. While TCE and PC-143 somewhat exceeded screening levels in production well water used for industrial process water (but not in potable well water), there is limited exposure to industrial process water. In addition, SWMU-impacted groundwater is contained on site. These findings are summarized in Figure 6.1, Human Exposure Pathway Evaluation. The figure indicates that potential exposure routes for site receptors (workers, riverbank trespasser, and construction worker) are either incomplete or insignificant and that groundwater migration to surface water is an incomplete pathway due to pumping. 6.6 ECOLOGICAL EXPOSURE EVALUATION The ecological evaluation focused on identifying whether significant ecological resources may be exposed to site-related constituents released from the SWMUs. According to USEPA guidance (USEPA 1997,1998a, 1998b), valued ecological resources are those that either provide critical habitat (such as wetlands or fisheries), are critical to sustaining populations of species or habitat, are reflective of public concerns (e.g., wildlife habitat for game animals), or are federal or state listed species that could be exposed and susceptible to site-related constituents. The study area for the ecological evaluation included the four SWMUs and surrounding terrestrial habitat. The ecological evaluation included a day and a half of field reconnaissance for habitat characterization (April 6 to 7,1999), principally along the portion of the property adjacent to the river, which includes the RBL/ADP. 6.6.1 Exposure Areas and Media Surface soil at the RBL/ADP is the only potential ecological exposure medium within the RFI study area. The PWI and BG SWMUs are covered with gravel, asphalt, or buildings and do not provide ecological habitat. Subsurface soil (greater than 2 feet) and groundwater are not exposure media of concern for ecological receptors, and groundwater does not discharge to surface water at the site. ^ cawMTtVutCmKMWajr tU^ltMtfAfWCOlMMlWOm^ -------------------------------------------------------------------------------------- CAMARY\720a7205RFI.DOCU9.JUN-99\720a 6-8 ^ Q EID090401 SECTOMSIX_____ screening level BisfcEyaluaflon 6.6.2 Habitat Characterization at the RBUAOP The RBL/ADP lies in a narrow band between the river and the main manufacturing area. It runs approximately 4,500-feet and rises 30 feet above the floodplain, covering a portion of the alluvial ten-ace on which the main plant is located. A layer of clean fill 6 to 36 inches thick was placed over the RBL upon closure in the 1960s. The southern side of the RBL is within the active manufacturing area and is covered with gravel or buildings. The ADPs were closed in 1988 and removed. The ponds were filled and capped and are now covered with grassy vegetation. The slope of the RBL/ADP is covered with hardwood trees, shrubs, grass, and other dense vegetation that has grown in the 30 years since the landfill was closed. The area between the RBL/ADL and the river is manicured grass, with a few trees and shrubs. At the upstream end of the RBL, the grassy area gives way to natural vegetation of trees and shrubs. Major vegetation species include beech, maples, oaks, ash, cottonwood, black willow, and sweetgum. Wildlife observations, including tracks, burrows, and scat, included small mammals (woodchucks, cottontail rabbits, squirrels) and deer tracks along portions of me river. It can be assumed that other small animals such as mice, voles, raccoons, and various reptile and amphibian species would inhabit the area near the riverbarik. Birds observed in the area were primarily bank swallows, crows, and redwing blackbirds. Other passerine birds will likely occur during different seasons. Hawks were observed hunting over the area and several species of waterfowl were observed on the river that might feed on vegetation on the riverbank. Ospreys, reintroduced by DuPont's Wildlife Habitat Enhancement Program, were reported by a plant employee to nest in the area. Bluebird and wood duck nesting boxes were placed near the river, but these species were not seen. 6.6.3 Identification of Significant Ecological Resources While numerous plant and animal species were observed along the riverbank area, no significant ecological resources such as wetlands, game habitat, or threatened or endangered species were identified within me RFI study area. In addition, according to the WVDNR, Wildlife Resources Section, no rare, threatened, or endangered species are recorded for the vicinity of the Washington Works plant Table 6.9 lists the terrestrial species that are listed as Rare, Threatened or Endangered (RTE) by both the U.S. Fish and Wildlife and the West Virginia Natural Heritage Program. In conclusion, no significant ecological habitat or species of special concern were identified within the study area, and therefore potential ecological impacts from constituents in soil at the SWMUs are expected to be insignificant. > ^ COMWRATC IWAMTMM OHQUP WteltlJ nwWCOttmfBittw ltay Ml Hm. UMHI 27 MHlVM, (Mwmt 18--0 0g > C:WARYl7205W205BFI3CU9-JUN49>720a 0<;-Qf S W s 0 u EID090402 SEGTIONSIX Screening level Risk Evaluation 6.6.4 Ecological Exposure Pathway Evaluation In conclusion, there appear to be no significant ecological resources or exposure pathways of concern related to-soil at the SWMUs. Groundwater is not an exposure medium for ecological receptors, because there are no surface expressions ofgroundwater at the site (water table is about 60 feet BGS). These findings are summarized in Figure 6,2, Ecological Exposure Pathway Evaluation. The figure indicates that potential soil exposure pathways are either incomplete or insignificant, primarily due to the absence of significant ecological resources in the study area, 6.7 SUMMARY AND CONCLUSIONS Soil at all SWMUs is not a medium of concern for human health because maximum observed concentrations in soil were below health-protective screening levels. In the well supplying potable water (AM07-PW01), constituent levels were below MCLs or other health criteria, so the water is not a significant source of exposure for workers. In wells supplying industrial process water, maximum concentrations of two constituents somewhat exceeded MCLs or health criteria for drinking water, but the water is not ingested, and therefore, the production well water is not considered a health concern under exposure conditions typical for industrial process water. SWMU - impacted groundwater is contained on.site by production well pumping. Ecological habitat in the study area is limited to a narrow band of woody or grassy vegetation along the river bank and slopes of the RBL/ADP, inhabited or visited by small mammals, birds, and other animals. No significant ecological resources were identified within the RFI study area, and no rare, threatened, or endangered species have been recorded for the vicinity of the Washington Works site. Because of the absence of significant ecological resources and the limited potential for exposure, ecological exposure pathways were concluded to be incomplete or insignificant. Table 6.10 summarizes the findings of the screening-level risk evaluation and ecological exposure evaluation. '' issast ^ CORPOIUTK IWOHTK)NaRDUP MMlMUbfhIUW OAM MW Rw we Omaxf OK.V l-wMiFua.MJqzr Wftmqkn.&tow l--MCOT > CO CMMRV\720a7205RFI.D002BN)UN4a720a 6-10 g UJ EID090403 7.1 CONCLUSIONS The main objectives-efthe Washington Works RFI were to determine the nature and extent of SWMU-derived waste constituents, and their rate of migration in groundwater and other media, and to identify whether or not potential releases are a concern for human health or the environment The RFI field investigation, groundwater flow modeling, and a risk evaluation were conducted to meet these objectives. The primary conclusions reached through completion of these efforts are summarized as follows: 1. Concentrations of metals detected in soils underlying and adjacent to SWMU areas are comparable to background concentrations. 2. The organic constituents detected in groundwater appear primarily to be attributable to releases from the RBL and ADP SWMUs. The BG SWMU does not appear to be a source for organic constituents detected in groundwater. 3. The extent of horizontal impact (i.e., laterally away from the edge of a SWMU) of organic constituents to soils near the SWMUs appears to be minimal, m general, releases from SWMUs migrate vertically downward through the vadose zone to Ac site aquifer. 4. Concentrations of organic constituents detected in soils underlying and adjacent to SWMU areas do not exceed USEPA Region III RBCs for industrial soils. This includes shallow soils (0-2 feet deep) and subsurface soils (>2 feet deep). 5. Two organic waste constituents, TCE and FC-143, were detected in groundwater from production wells. Their concentrations exceeded health-based screening levels. However, this impacted groundwater does not present a human exposure risk as it is primarily used for non-contact industrial purposes. 6. In the methylene chloride seep area (i.e., RBLL1) the horizontal extent of impact (i.e., toward the river) is minimal. The active french drain collection system effectively contains seepage, prevents human exposure, and prevents off-site migration. This system is an effective final remedy as constructed. - 7. No significant human or ecological exposure pathways to SWMU-impacted soils or ,, groundwater exist. SWMU soils are covered and rendered inaccessible by overlying " buildings, asphalt or dense vegetation. All but two organic constituents in site aquifer groundwater are below health-based screening levels; however, since the groundwater is primarily used for non-contact industrial purposes, it is deemed not a threat to human health. 8. The current groundwater flow model demonstrates complete capture of SWMU-impacted groundwater by the production well system and, although not planned, this capture would continue even with a 65% reduction in pumping rates. 41EBD ^ aw wav com-oKATt mutoAncn AtlUtoKMMMM OuAM id nr we OhHwotf Iwtey 1M nua. IMMkf 27 > CO /-I S C:lMARW2fl517205RFI.OOCl29-.IUN-99W205\ 7 1 0 U> 0 ) EID090404 SEGTIBMSEVEN _____Goncmstons/BacniBmenilations 7,2 USEPA ENVIRONMENTAL INDICATORS The following summary is provided to address USEPA's newly implemented Environmental Indicator program^-Ihe primary objective is to present RFI conclusions that specifically pertain to CA 725-Human Exposure Under Control and CA 750-Contaminated Groundwater Migration Under Control evaluation criteria. 7.2.1 CA 725-Human Exposure Under Control As noted in Section 6.5 and Section 7.1, there are currently no complete or significant exposure pathways to SWMU-impacted soils or groundwater. 7.2.2 CA 750-Contaminated Groundwater MigrationUnder Control As demonstrated by the site-wide groundwater flow model, current production well pumping prevents off-site migration of SWMU-impacted groundwater. 7.3 RECOMMENDATIONS DuPont recommends the following future activities at the Washington Works Plant site pertaining to the HSWA permit/Corrective Action Program: Q Continue operation of the methylene chloride seep collection and treatment system (RBLL1) as a final remedy. Q Maintain production well pumping at or above 35% of present levels. Q Conduct long-term groundwater quality and site aquifer potentiometric surface monitoring to ensure me continued protection of human health. Q Conduct long-term groundwater potentiometric surface monitoring to ensure the continued capture of site groundwater. : It is proposed that this monitoring occur semi-annually. A set of specific wells will be sampled for a parameter list consistent with currently identified groundwater quality impacts. Groundwater elevation measurements and samples would confirm the effectiveness of production well pumping as the means of preventing off-site migration ofSWMU-derived waste constituents. DuPont will prepare a long-term groundwater monitoring plan upon direction from USEPA Region III. 1BB> ^ COflPOflATE RCMGCNA710H ffiWUP Cllftrt ml Tin H'r OfMimrf filing > w C:WARV\7205\7205RFI.OOC\2S.JUN-9S\7205\ 7-2 S 0 LtJ 0 00 EID090405 90^060(313 SECTiBNEIGHT__________________References Braun, E. L. 1950. Deciduous forests of the eastern North America. BIakiston Company. Philadelphia, PA: The Cariston and Graeff. June 30,1955. Grovndwater Resources of the Ohio River Valley in West Virginia. West Virginia Geological Survey. Vol. 22. DuPont. 1990. Washington Works 1990 Preliminary Hydrogeologic Assessment. Solid Waste & Geological Engineering Department 1992. Verification Investigation E.L DuPont de Nemows Co. Washington Works April ____.1992. (Vol. 1). ____. 1997. RCRA Facility Investigation Plan, DuPont Washington Works, September 24, 1997. Corporate Remediadon Group. Fenneman, Nevin M. 1938. Physiography of the Eastern United States. New York: McGrawHill. GE Plastics. 1996. Groundwater Elevation Map. June 18-19. Geraghty & Miller, Inc. 1993. CALSTATS: A Model Calibration Utility that Compares ModelComputed Values with Field-Computed Values, 1993. Hamilton, William J. and John 0. Whitaker Jr. 1979. Mammals of the Eastern United States. Ithaca: Comell University Press. Haskell Laboratory. 1991. Ammonium Perflwrooctanoate (FC-I43). HydroTrak, Inc. 1999. ModelCad For Windows: Groundwater Modeling. Computer Aided Design Software for Lubeck Public Service District. April 19, 1999. Telephone conversation between Jim Cox, Manager, Lubeck PSD, and Patricia Westphal, URSG-Woodward-Clyde. McDonald, M. G. and A. W. Harbaugh. 1988. A Modular Three-Dimensional Finite-Difference Groundwater Flow Model. If. S. Geological Survey, Techniques of Water Resources Investigations. Chapter 6-A1. pp.586. 'sssss ^ COWOWVa REMCBM10H GROUT WPWttWiSrtMWWOtUMUIVMIV M^ Mfl rha. dHlir 27 CO o i ClARYl7ZOa7205RFI.DOC30-JUN-99l720 0-1 g 0 <*> 0 VO SECTMIIEIGHT___________________References McDonald, M.G. and Harbaugh, A. 1998. A Modular Three-Dimensional Finite-Difference Groundwater Flow Model (MODFLOW). USGS Open File Report 83-875. National Climactic Data Center, National Oceanic and Atmospheric Administration web site. Pollack, D.W. 1994. User's Guide for MODPATH. Version 3: A Particle-Tracking Package for MODFLOW. Pollack, D.W. 1989. User's Guide for MODPATH/MODPATH PLOT. Version 3: A ParticleTracking Postprocessing Package for MODFLOW. The United States Geological Survey Finite-Difference Groundwater Model. USGS Open File Report 94-464. Schultz, R.A. 1984. Groundwater Hydrology of the Minor Tributary Basins of the Ohio River, West Virginia. Smith, Roy L. March 7,1995. Risk-based Concentration Table January-June 1995. Region HI memorandum. USEPA USEPA. 1986. Test Methods for Evaluating Solid Waste Physical/Chemical Methods. SW-846 Third Edition. 1989. RCRA Facility Investigation Guidance. Office of Solid Waste EPA/SW-530-89- ____.31. July 27,1990. Proposed Rule: Corrective Action for Solid Waste Management Units at ____.Hazardous Waste Management Facilities. EPA/SW-530-90-012. November 1992. RCRA Groundwater Monitoring': Draft Technical Guidance. Office ____.of Solid Waste. EPA/530-R-93-001. ____.May 31,1994. RCRA Corrective Action Plan (Final). Number 9902.3-2A. USEPA Directive December 1996a. Recommendations of the Technical Review Workgroup for Lead for ____.an Interim Approach to Assessing Risks Associated with Adult Exposure to Lead in Soil. Technical Review Workgroup for Lead. 1996b. Soil Screening Guidance: Technical Background Document. USEPA/540/R- _____.95/128. ^ UT ReMEOMTXMQAOUP s.-sas. > C:WARW20a720SRF1.0002MUN.99l720a 8-2 2 EID090407 SECTMMjEIGHT_____________Beterenees ____. 1997. Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments (Interim Final). Environmental Response Team. Edison, NJ. ___. May 5,1997. Verification Investigation Report Notice of Deficiency. Mary Beck to W. M. Stewart. Letter from April 1998a. Guidelines for Ecological Risk Assessment. Risk Assessment Forum. ____.USEPA/630/R-95/002F. 1998b. Ecological Risk Management Principles for Superfund Sites (Draft Guidance). ____.Office of Emergency and Remedial Response. USEPA Region HI 1993. Selecting Exposure Routes and Contaminants of Concern by Risk- Based Screening. Technical Guidance Manual. USEPA/903/R-93-001. April, 1999. Risk-Based Concentration Table. ____. United States Geological Survey, Water Resources Web Site W-C Diamond. August 18,1998. RFI Work Plan: Groundwater Model Update Report. West Virginia Division of Natural Resources (WVDNR). May 12,1999. Correspondence from Barbara Sargent, Wildlife Resources Section, to Don Spires, URSG-Woodward-Clyde. West Virginia Division of Environmental Protection. May 1, 1996. 47 CSRCO, Monitoring Well Design Standards, Office of Water Resources. itBBt A eowowRcwounoHmoup OifwtwS'niCOInwuftQMi twMin^M*q9 CaMARY\7205<7205RFI.DOC130-JUN-99720S 8-3 I g 0 U EID090408 EID090409 FIGURES '. EID090411 ZT^osoaia T^06oaia .< . . SCALE 600 0 600' ^ 7205C006 ffi loBST najRCNOu' 2.4 IDATET 05/24/99 0 u EID090414 VST a-roSM PLEISTOCENE AGE ^^SBS/MMSE\ Ohio River Terrace Deposits "-"-:13;"-"-^"-1":?\.^.-^0:-..0\Q:-.-.^?SS :"'E^^^-^'-" S^-?-?-0:-; ' 0- \.?b-2^>". -O-Q-.o". 0-Q-:i :^-><-. 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""' 0 ^:-0 Q:' '^.Qyb-o'1-^ -0-b^"^o-Q1 "o^ :D.a<S"-%.-Q-"0"-:0--Q--P:'-"lS-":'P:"---"-'"Sfr'-"-'"--1'P: -":-:o-"-'^-^''o":-^-"'^ -0 ^^g-.; -.'-'0. :'-'v3. l-:<^i-Q-:o"--Oi&o-.-0-Q- ^ _^'-^-.O^^'ca'^O/Q^^iQy-^L-Q -"X:"^'- -":'P;;; ^ ^ o 0 ^ ^ ^ ^ ^ ^ ^ ^ " Q:.^Q<[--'ii>'. ^.'Q'-'O'- 'OKC'-O- l^Z.:'?:":":'- ^:": ^- :'P: ^ ^"'^"s01;-.^'0;-"-^"0^ -"^"-'^Q)^:^ b^o^-b'-Ql" -^^^^'i^^.-^^-^ : --(o---': :" ."'o-'-".^"- .''cr"-": :' ."I ^;:n^^:^Q^^-o;1 _3^--0-:0^^-:S:^^ .t"^-:ip:-:--:y:'-j^ ai .||^ J3a"-cb---Q.:.'.ct>:".-.-.oyQ:_<=->"-.-o:^-..yo'.--:o-:- f-,'-- - ".Q--- ".y<"-"-->pr:-.'.?1 .-.-.P .-IN'^- y^^o^o^go^ ^ 1 ^ ^ ? + o-0'. b-o-^>".-b-o-.-o". b o- o. o- : ipv :---.?''0:--.?>"c --s ^"(^--'^^^^^^o^^^^^--.^^^^^^sy^---^^;^^p^0^?^^^^-0i^)^^^^^?^^^ .| g-: 'iO.-.O .o--..0.c>:-..0 0^ 0---; ..-'0--;: .-'O---:. ^ .^Q(;.^Q{.:b-c '/^&^^^W^%^c^^ ^^^^ ^Q^^O'?;.^C^ /'^^.^g^^-i^N^l^^^^^ ^^t>:;o^;l,| 'Q-Q'-O'- iQ^'-'O-0:-3-fi^ :-' n^ rJ-q^-'rr'T'lPri'lT'Tl? "^ ^<^^1^|^^^^ - - 'Nc.f0^-^^^^^^^^^^^^^ ^e?^':^ '"P/Q-^O.-Q-^-) ^Q^.bo^^ ;-;--'0--::-.-'0-- is.-t l--'o-:D.-Q--0"-:0.^--t\-^ ^o^^o^e,^:\ 1---::-.-0--";:-.-'0--- nSM 8B N011VA313 ,'") U- ^^-' EID090415 gS-Z suiigid /" \ Y /' Figure 2.5C SItODOHSV w ASH000320 3B'Z9-"'SV[ <'- ^ L, EID090419 ASH000321 SS-Z, ssaSiS. L^ EID090420 w p -- --fi40-- ----630-- --<20-- t -i u w --610---- t a 30 SCALE 0 100 i FEET / / S s ---------- :-- JL -- ///tS ---- ^ ^'''^^ ?:: :(: .'> 1=1^^ ^: --:^: -- -- -- 2 -- E== -------- i ^ l f. '-- n '"A Ilil! t ^ - ,-< K-- ,sv a -' S i g ----600-- ^= ! ^^Vs 1 u ^1^ --590-- ^ W / i ^ ...NORMAL POOL SBSE------./ SS' ;"5.; ^ --sao-- ^ '"' 'lv. 7^ s K ii,/ ///i^/ /'/ ^1 --570-- ^y/ |j OHIO RIVER /L^" 1 y /L.--,-- i --S60-- T^^i ^ ^ ^ s /7^ ?; if F- I f / ^ ^^i l ^::': :''?' >.' f*.* ./--" ^?;:: ^ 'i': i" ^ --sso-- ^ K| *^ ^ < .'; .' ;^ !' ^' * 4 ^ 1 ;* f(, :: . :' .. 1;'- .^' ; 3; 1 ?^ '" ?'.; fc ';; kri ;' ? ^''.I* 1 & : .^"*: ^^ ':: :'; *^ 1 v. :;'' ;^ ^ m .s"' a. ;. ^^7?^^^^^ 7/7/y^ ^540^ ^ ^ ^ ^' :>. " ^? ?^ > <: -". ;;.'. u i-^ ''. a --S30-- ^| j CLAY j^j SANO a SfUkVei. W?7^7- ^ ts FIGURE 2.6 CROSS SECTION BASED ON TEST BORINGS AT E.I-duPONT dNEMOURS, POLYCHEMICALS DIVISION, WASHIN6TON BOTTOM, SHOWIN8 RIVERBANK SLUMPlRQ OF FLOOD-PUUN CLAY. Source: Cariston and Graeff 1955. EID090421 EID090422 WEOOOHSV r'- . jMt-m-WW. .- '* * . . ^y:.y.^s.s^^^': /..:.,: ^ass\ EID090425 EID090426 8ZCOOOHSV EID090428 EID090429 EID090430 c r 43 Soil Results (mg/kg) 10-220 221 -1000 1001-2400 2401-11000 11001-48000 )!e results for one sample on indicates that multiple ample were collected for aa depth range G Corporate RmMliathMi Group AnWCinebtw9ii DufiwitsMi nw W-C Dlwaamt Group BwhyVUPHm. BiMhgXf wamhgeon. OulHw 19SWI-W27 IH SO tepp& SO .1/99 Wash.apr FIGUENO: 4.7 EID090431 .. -143 Soil Results 10-60 61 -170 171-600 601 -1200 . 1201 - 9500 (mg/kg) ^.^"" Corporate Remediation Group An AISsneu 6(Mwm Dupont nd 77 W-C DtfrnomS Group Buhy M Pim. BitUhy 27 Wllminston.Dtwiar19eaa-W27 /lultspleresults for one sample ^cation indicates that multiple oil sample were collected for he soil depth range "aSSBS--i JH SO topft: 0 so 31/99 Wash.apr 4 . 8 tNOl; EID090432 c EID090433 EID090434 r )arbon Tetrachtoride Results (ug/1) 1 2-16 ^ Wells not Sampled Corporate ftemediation Group Add.apr AaMSenobtMii 6B Oiipwitend 7R* W-C OtuaoiHl Group 4.11 BsitoyUS film. Building 27 c Wilmtnstw. Ortnmro 1SSSO-e027 H GB ' ^JDD hiro: RCV- i/19/99 fWWEVO. EID090435 ^' ..a < bon Tetrachloride Results (ug/1) 1 . 2-15 Wells not Sampled c rwn Corporate Remedlation Group ^ Wash.apr An AHince batwsn so Duponi and Th W-C Diwnond Group 4.12 uwf BwhymiaiaP>l--o--u--., wBuuwiludiilnlWg 26r7 l\ Wilmlngtoti. Dslowaro 198WWS7 SO Hf9\l/f9\f9\ SST SO IWPD- REV.: RUENUkBBt: ROURENO.: EID090436 ^-A achSoethene Results (ug/1) 1-2 \ ^ 3-5 \ \ 6-8 9-17 18-240 Corporate Rsmediation Group An AISwc between Dupmt and Tho W-C Diamond Group Borisy Mill Plaza. Building27 WOmiti^on. Diawai 1990W27 nn'JH '99 WPOL: REV.: GB GB RifiNUMBae Acid.apr RGURE NO- 4.13 EID090437 n Figure 4.14 ..... j- g8=^TS i i i N) 01 . 0 J^CJI (0 o i 0 0) 0 g) ^ <D (D 73 I i<^^ 6OOOHSV c v iroethene Results (ug/1) 1-5 3-61 32-150 151-400 401 - 800 Corporate Rmnadiation Group Acid.apr An ASsno batwMn c DupoiiffnslTlwW-CDhimind Group 4.15 BufyMHPhzs. BaSiHss W WSmtnetM, IMIHUM 198WI-W27 RJH GB hMWU GB GB wiT 5/19/99 fasluueeST F10UFENO- EID090439 c ..A Al, ( ;hloroethene Results (ug/1) 1-5 6-36 37-63 64-150 151-670 auuiiig Co ate Remedladon Group Add.apr AisAISsnclwtnui Dupsint wiS TIM W-G Qftmentf Group c BwSyMPlas. BuaiOas 27 4.16 IWmington. Orinmrr 188804027 SST < RJH HKD- GB to-a: ATR 5/19/99 GB GB RUiNuiffat" neiffiENO: EID090440 r ound 1: Freon 113 . 2-130 . 131-860 861 - 2200 2201 - 3700 3701-7100 Results (ug/l) Corporate Remediatfon Group c msm AllAiellc*lwtwmi Dupvntstiel Tin W-C Olsmend Group 4.17 BufuyMSPIm, BsiSiangST WSinlntrtsn. Dattvwn 198BO-W27 GB Wpa: -GB. 5/19/99 Acid-apr neuRE NO- EID090441 --KE ^\^^^^'/^-- ~ ^ , ^^ * found 2: Freon 113 . 2-80 . 81 - 380 . 381-890 891 - 2200 2201 - 3600 Results (ug/l) <@JPDN1)Corporate Remediatiwi Group AflASfineslseiwsan DupantsiunhoW-QDItmwiiSQtOUp BulayMSPIu,BuS<Slng27 WImlnstw, DteMm lam-MUT <^ RJH uvo: QQ 5^ -------------- WM- QIQQ GB GB 1 Add.apr fnauiSHO- 4.18 EID090442 -. r r. EID090443 A 0: u, . EID090445 EID090446 EID090447 EID090448 ^ Figure 5.6 Groundwater Model Summary DuPont Washington Works Parkersburg, West Virginia Calibrated Groundwater Model - February 1,1999 Data Set 560 565 Target Groundwater Elevation (feet MSL) . .dure 5.7 Groundwater Model Summary DuPont Washington Works Parkersburg, West Virginia SENSITIVITY ANALYSES 0 a x X < 0 0 0 A A -- ZSEOOOHSV 555 560 565 570 575 Target Head (feet MSL) Note: Best fit line based on linear regression of data set. w' t ..,-re 5.8 Groundwater Model Summary DuPont Washington Works Parkersburg, West Virginia Model Verification - November 1997 & November 1998 Data Sets id SOOOHSV 550 555 560 565 570 Target Groundwater Elevation (feet MSL) Note: Best fit lines based on linear regression of data set. 6-S SOURCE MATERIALS Ihl FORMER BG AND RBL/ADP WAY STATUS IECEPTORS FUTURE RECEPTOR faverbank respasser Construction Worker 0 0 0 0 0 0 0 0 0 NOTES: DUPONT WASHINGTON WORKS MI WASHINGTON, WEST VIRGINIA Potentially Complete and Potentially Complete but Ir Blank Indicates an Incompj OAT6 MM* DATE: MOO MVER'BANK LANDFILL ANB ANAEROBIC DIGESTION PONDS UN EXPOSURE PATHWAY EVALUATION |nuENa |4d06W720599 FIGURE 6.1 S:\ltMWiOtw72.05UAxld,jtl^HllMAN(2)W2WM:45 PM Page I of I EID090454 SOURCE 'OSURE ROUTE PATHWAY STATUS POTENTIAL ECOLOGICAL RECEPTORS MATERIALS IN RBL/ADP vbsofption 1 <S & 00 000 00 00 0000 NOTES: * 0 DUPONT WASHINGTON WOKSRFI PotentiallyComplele and SlBnificairtPaliay ___ PrtenffallyComptetbBut InsignificantPathway _ _ B*la_ n_k, I. mf-- cates an Incomplete Pathway: RaceptoDow WASHINGTON. WEST VIBCiNIA {jcnHiBacaiiofwt.uiwa__t_J__M__i[&uTfE^: Mt s-20-n '"W*NKI-"IDnLLANn ANAEROBIC DIGESTION PONDS -;tCAL EXPOSURE PATHWAY EVALUATION SMmmmnami, FIGURE u Pigclofl EID090455 TABLES EID090456 TABLE 3.1 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Background Burning Ground AE11-SB01 0 59 AI10-SB01 0 AP10-SB01 0 E13-SB01 0 G17-SB01 0 N20-SB01 0 P14-SB01 0 T14-SB01 0 Y14-SB01 0 76 Z11-SB01 0 AA06-SB01 0 6 14 20 40 64 AA07-SB01 0 AA07-SB02 0 4 AA08-SB01 0 4 AA08-SB02 0 AC06-SB03 0 6 12 34 48 62 AC06-SB04 0 6 14 34 54 62 AC06-SB05 0 6 12 18 40 62 Page 1 of 5 2 10/6/98 61 10/6/98 2 10/14/98 2 10/14/98 2 10/7/98 2 10/14/98 2 10/14/98 2 10/14/98 2 105.'W 2 10/5/98 78 10/5/98 2 10/5/98 2 9/2/98 8 9/2/98 16 9/2/98 22 9/2/98 48 9/2/98 66 9/2/98 2 9/16/98 2 9/27/98 6 9/27/98 2 9/27/98 6 9.'27'98 3 9'27'98 2 8/31/98 8 8'31.98 14 8/31/98 36 8/31/98 50 8/31/98 64 8/31/98 2 9/1/98 8 9/1/98 16 9/1/98 36 9;1/98 56 9.'!'98 64 9/1/98 2 9/9/98 8 9/9/98 14 9/9/98 20 WW& 42 9/9/98 64 9/9/98 borings.xls EID090457 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION - DUPONT WASHINGTON WORKS PLANT Burning Ground (coat) AC07-SB02 AC07-SB03 AC07-SB04 AC08.SB01 AC08-SB02 Y07-SB01 Z06-SB02 Z06-SB03 Z06-SB04 Z07-SB01 Z09-SB01 0 2 9/9/98 18 20 9/9/98 62 64 9/10/98 0 2 9/14/98 8 10 9/14/98 20 22 9/14/98 64 66 9/15/98 0 2 9/14/98 10 . 12 9/14/98 20 22 9/14/98 60 62 9/14/98 0 2 9/27/98 S 10 9/27/98 58 60 9/27/98 0 2 8/24/98 10 12 8/24/98 20 22 8/24/98 30 32 8/24/98 40 42 8/24/98 50 52 8/24/98 56 58 8/24/98 0 2 9/22/98 8 10 9/22/98 22 24 9/22/98 6: 64 9/22/98 2 4 9/22/98 8 10 9/22/98 62 64 9/22/98 0 2 9/15/98 10 12 9/15/98 60 62 9/15/98 0 2 9/11/98 10 12 9/11/98 64 66 9/fl/98 0 ^ 9/10/98 10 12 9/10/98 20 22 9/10/98 62 64 9/11/98 2 4 9/3/98 8 10 9/3/98 14 16 -9/3/98 20 22 9/3/98 40 42 9/3/98 Page 2 of 5 borings.xis EID090458 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Burning Ground (cont) Z09-SB01(cont) 60 River Bank Landfill AA04-SB01 0 6 14 30 AA05-SB01 0 8 20 60 AB06-SB01 4 10 18 40 58 AB06-SB02 2 10 18 40 62 AB07-SB02 0 4 10 14 20 40 60 AB08-SB02 0 4 AC04-SB01 0 20 28 AE05-SB02 0 34 58 AF05-SB01 0 30 AH05-SB01 0 4 A106-SB01 0 18 36 48 60 it- 62 9/3/98 2 8/20/98 8 8/20/98 16 8/20/98 32 8/20/98 2 9/23/98 10 9/23/98 22 9/23/98 62 9/23/98 6 9/1/98 12 9/1/98 20 9/1/98 42 9/1/98 60 9/1/98 4 9/8/98 12 9/8/98 20 9/8/98 42 9/8/98 64 9/8/98 2 94/98 6 9/4/98 12 9/4/98 16 9/4/98 22 9 4'98 42 9'4'<?8 62 9/4/98 2 9.2798 6 9/27/98 2 8/21/98 22 8'21.'98 30 8.'21/98 2 8'22/98 36 8/22/98 60 8/22/98 2 82298 32 8/22/98 2 10-'14/98 6 10.'14'98 2 8/23/98 20 8'23/98 38 8Q3A8 50 8'23/98 62 8'23/98 Page 3 of 5 borings.xis EID090459 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT River Bank Landfill(cont) K04-SB01 0 12 L04-SB01 0 8 L06-SB01 0 10 22 66 M04-SB02 0 8 14 M04-SB03 0 6 14 M04-SB04 0 10 M04-SB05 2 6 12 M06-SB02 2 8 20 66 N04-SB01 0 12 N04-SB02 0 8 14 N05-SB01 2 8 20 70 004-SB02 0 6 14 004-SB03 0 10 14 Q04-SB03 0 8 S04-SB02 0 8 18 Page 4 of 5 2 10/12/98 14 10/12/98 2 10/12/98 10 10/12/98 2 9/25/98 12 9/25/98 24 9/25/98 68 9/25/98 2 10/10/98 10 10/10/98 16 10/10/98 2 10/10/98 8 10/10/98 16 10/10/98 2 10/12.'98 12 10/12/98 4 10/12/98 8 10/12/98 14 10/12/98 4 9/28/98 10 9/28/98 22 9/29/98 68 9/29/98 2 10'12 '98 14 10'12'98 2 10/9/98 10 10/9,98 16 10/9/98 4 9.-2S19S 10 9'28 98 22 9/28/98 72 9/28/98 2 10/11/98 8 10/11/98 16 10,11'98 2 10'12.'98 12 10/12/98 16 WHW 2 IO'H/98 10 IO'H/98 ^ 10/11/98 10 10/11/98 20 10,'11'98 borings, xls EID090460  BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASfflNGTON WORKS PLANT River Bank Landfill(cont) S05-SB02 "2 10 40 66 T04-SB01 0 10 16 U04-SB01 0 4 16 V04-SB01 0 4 18 Y04-SB01 0 10 30 Anearobic Digestion Ponds P04-SB02 0 8 14 P05-SB02 2 22 42 68 R04-SB02 0 10 18 4 9/26/98 12 9/26/98 42 9/26/98 68 9/26/98 2 10/10/98 12 10/10/98 18 10/10/98 2 9/30/98 6 9/30/98 18 9/30/98 2 9/29/98 6 9/29/98 20 9/29/98 2 8/20/98 12 8/20/98 32 8/20/98 2 10/9/98 10 10/9/98 16 10/9/98 4 9/24/98 24 9/24/98 44 9/24/98 70 9/24/98 2 I0'9'98 12 10 ''98 20 10/9-'98 Page 5 of 5 borings.xls EID090461 TABLE 3.2 ANALYTICAL PARAMETERS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT River Bank Landfill/ Anaerobic Digestion Pits Polvacetal Waste Incinerator Burning Ground . Soil Groundwater Soil Soil '.. Methylene chloride Tetrachloroethene Trichloroethene Freon-113 FC-143 Arsenic Barium Cadmium Lead Nickel Methylene chloride Tetrachloroethene Trichloroethene FC-143 Arsenic (dissolved/total) Barium (dissolved/total) Cadmium (dissolved/total) Lead (dissolved/total) Nickel (dissolved/total) pH (field) Temperature (field) Specific conductivity (field) Dissolved oxygen (field) Redox (field) Chromium Carbon Tetrachloride FC-143 Arsenic Barium Cadmium Lead Nickel RBL = Riverbank landfill (SWMU A-3) ADP = Anaerobic digestion ponds (SWMU B-4) BG = Burning ground (SWMU H-14) PWI = Polyacetal waste incinerator (SWMU C-6) SW-846 8240 SW-846 8240 SW-846 8240 SW-846 8240 7060 6010 6010 7421 6010 SW-846 8240 SW-846 8240 SW-846 8240 7060 6010 6010 7421 6010 -- -- -- ... -- 6010 SW-846 8240 7060 6010 6010 7421 60)0 Page 1 of 2 tabl3.2.xls EID090462 Burning Ground (cont) Background TABLE 3.2 ANALYTICAL PARAMETERS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Groundwater . -Carbon Tetrachloride Arsenic (dissolved/total) Barium (dissolved/total) Cadmium (dissolved/total) Lead (dissolved/total) Nickel (dissolved/total) FC-143 pH (field) Temperature (field) Specific conductivity (field) Dissolved oxygen (field) Redox (field) Soil Metfaylene chloride FC-143 Arsenic Barium Cadmium Chromium Lead Nickel Groundwater Meth\ iene chloride Tetrachloroethene Trichloroethene Freon 113 FC-143 Arsenic (dissolved, lotalj Barium (dissolved/totall Cadmium (dissolved/total) Chromium (dissolved'total) Lead (dissolved/total) Nickel (dissolved/total) pH (field) Temperature (field) Specific conductivity (field) Dissolved oxygen (field) Redox (field) RBL = Riverbank landfill (SWMU A-3) ADP = Anaerobic digestion ponds (SWMU B-4 BG = Burning ground (SWMU H-14) PW1 = Polyacetal waste incinerator (SWMU C-6) Page 2 of 2 SW-846 8240 7060 6010 6010 7421 6010 -- -- -- -- ... SW-846 8240 SW-846 8240 7060 6010 6010 6010 7421 6010 SW-846 8240 SW-846 8240 SW-846 8240 SW-846 8240 7060 6010 6010 6010 7421 6010 --. -- ... ... ... tabl3.2.xls EID090463 TABLE 3.3 NEW WELL CONSTRUCTION INFORMATION RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT ^ ' : ^ Borehole ID 1 De(Sthto WellTO ;W1.. W Screen Length Bottom Diameter Size sieefrTo AA04-MWOI.SBOI TW-70 43 2" 10 10 43 33 43 31 31 AA05-MW01.SB01 TW-7t 70 2" 10 10 70 60 70 58 58 AB07-MW02.SB02 TW-72 72 2" 10 10 72 62 72 60 60 AC07-MW02.SB02 TW-73 74 AF-ll-MWOI.SBOl TW-74 72 A106-MWOI TW-75 72 U13-MWOI.SB01 TW-76 74 G17-MWOI,SB01 TW-77 80 L06-MWOI.SBOI TW-78 77 M04-MW02,SB02 TW-79 25 M04-MW03.SB03 TW-80 26 N04-MW02.SB02 TW-81 26 N05-MWOi,SBOI TW-82 82 P04-MW02,SB02 TW.83 28 P05-MW02-SB02 TW-84 80 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 74 64 74 62 62 72 62 72 58 58 72 62 72 60 60 74 64 74 60 60 80 70 80 68 68 77 67 77 65 65 25 15 25 13 13 26 16 26 14 14 26 16 26 14 14 82 72 82 70 70 28 18 28 16 16 80 70 80 68 68 R04-MW02,SB02 TW-85 28 2" 10 10 28 18 28 16 16 S05-MW02.SB02 TW-86 78 2" 10 10 I104-MWOI.SB01 TW-87 27 2" 10 10 78 68 78 66 66 27 17 27 15 15 V06-MW01 TW-88 77 2" 10 10 77 67 77 65 . 65 W05-MWOI TW.89 76 Y14-MWOI.SBOI TW-90 90 /06-MW02.SB02 TW-91 72 /.117-MWUI.SBOI h'W-92 74 /0)-MW(I.SBOI TW-93 70 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 76 66 76 64 64 90 80 90 73 73 72 62 72 60 60 74 64 74 62 62 70 60 70 58 58 S9EOOOHSV Page 1 of 1 TABLE 3.4 Borehole ID Welt ID AA04-MWOI..SB01 TW-70 AA05-MW01.SBOI TW-71 AB07-MW02.SB02 TW-72 AC07-MW02,SB02 TW-73 AEII-MW01.SBOI TW-74 A106-MWOI TW-75 EI3.MW01,SBOI TW-76 G17-MW01.SBOI TW-77 L06-MWOI.SB01 TW-78 M04-MW02,SB02 TW-79 M04-MW03.SB03 TW-80 N04-MW02.SB02 TW-81 N05-MW01,SBOI' TW-82 P04-MW02.SB02 TW-83 P05-MW02-SB02 TW-84 R04-MW02.SB02 TW-85 S05-MW02.SB02 TW-86 U04-MW01,SB01 TW-87 V06-MW01 TW-88 W05-MWOI TW-89 Y14-MWOI.SB01 TW-90 Z06-MW02(SB02TW-91 Z07-MWO|{SB01 TW.92 709.MW01.SBOI TW.93 Design Stickiip(2.6') Stickup(2.6') Stickup(2.5') Flushmount Flushmount Flushmount Stickup(2.I5") Stickup(2.5') Flushmount Stickup(2.15') Stickup(2.05') Stickup(2.35') Flushmount Stickup Flushmount Stickup(2.00') Flushmount Stickup(2.5') Flushmount Flusbmount Stickup(2.5') Flushmount Stickup(2.45') Flushmount WELL DEVELOPMENT INFORMATION RCRA FACILITY INVESTIGATION DUI'ONT WASHINGTON WORKS PLANT Date 10/7/98 10/7/98 10/11/98 10/12/98 10/8/98 10/7/98 10/9/98 10/9/98 10/9/98 10/12/98 10/12/98 10/12/98 10/9/98 10/12/98 10/9/98 10/12/98 10/13/98 10/7/98 10/8/98 10/11/9S 10/8/98 10/8/98 10/11/98 10/13/98 Depth ftoi Bottom 45.40 73.45 75.35 73.60 71.90 71.90 76.80 83.10 78.25 25.50 28.45 28.85 82.40 30.30 80.25 30.40 76.85 29.85 75.65 76.20 93.85 71.40 77.05 70.10 ^ 1C' wrw '^ )lume 30.85 12.37 64.30 .49 64.25 .81 62.60 .79 60.30 .89 62.10 .60 63.50 2.17 72.35 .75 68.20 .64 14.55 .78 14.45 2.28 14.80 2.29 71.35 27.10 .80 (152 69.00 .83 14.45 2.60 66.70 .65 11.45 5.00 65.95 .58 65.10 .81 77.75 2.62 61.65 .59 65.45 .89 57.90 .99 ' 7PKI|^?| 30 20 30 30 20 20 25 25 20 25 25 25 25 10 25 30 20 30 20 20 30 20 30 20 126 13.4 16.6 16.7 10.6 12.5 11.5 14.3 12.2 14.0 11.0 10.9 13.9 19.2 13.6 11.5 12.1 10.0 12.6 11 1 11.4 12.6 15.9 10.1 Bailed G Pump/Bail Da Pump/Bail Br Pump/Bail Br Pump/Bail D Pump/Bail B Pump/Bail D Bailed B Pump/Bail Br Pump Li Pump B Pump Li Bailed Li Bailed D Bailed D Pump B Pump/Bail Br Bailed B Pump/Bail D Pump/Bail B Bailed D Pump/Bail B Pump/Bail B Pump/Bail D 99OOOHSV Page 1 of 1 TABLE 3.5 GROUNDWATER ROUND 1 DEPTH TO WATER MEASUREMENTS RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT AA04-MW01 AA05-MW01 AB07-MW02 AC07-MW02 AE11-MW01 AI06-MW01 AM07-PW01 E13-MW01 F06-MW01 G17-MW01 KI6-PW01 L04-PW01 L06-MW01 L17-PW01 M04-MW02 M04-MW03 M16-MW01 N04-MW02 N05-MW01 N13-MW01 P04-MW02 P05-MW02 P06-MW02 POS-MWOI Q04-MW02 Q05-MW01 R04-MW02 S05-MW02 T13-MW01 U04-MW01 V05-PW01 V06-MW01 V09-MW01 W05-MWOI Y14-MWOI Z06-MW02 ZO-'-MWOl Z09-MW01 TW-70 TW-71 TW-72 TW-73 J 11/9/98 11/9/98 11/9/98 11/9/98 TW-74 11/9/98 TW-75 11/9/98 336 TW-76 TW-M6 TW-77 L4(354) Gallery 11/9/98 11/9/98 11/9/98 TW-78 LI (351) TW-79 TW-80 11/13/98 11/9/98 11/9/98 TW-55 TW-81 TW-82 TW-54 TW-83 TV-8.4 11/9/98 11/9/98 11,'13/98 IIWS 11,'9,'98 !) ]3'98 TW-52 TW-53 11/13/98 11/9/98 TW-50 11/9/98 TW-51 1].'13'98 TW-85 TW-86 TW-24 TW-87 11 9-'98 11 13'98 11/9/98 11/9/98 Rannev TW-88 11/9/98 TW-3 TW-89 11/9/98 11 '9'98 TW-90 11'9'98 TW-91 11/9/98 TW-92 11 '9'98 TW-93 11 '9 '98 1117 1505 1445 1438 1134 1427 1224 1215 1205 1048 1051 1049 1155 1055 1200 1417 1059 1402 1130 1539 1045 1019 1104 1534 1148 1109 1519 1525 1510 1140 1459 1456 1450 44.44 73.11 75.01 73.14 71.52 71.61 76.58 62.8 82.49 77.96 26.86 28.28 71.57 28.51 82.15 70.48 30.02 79.86 73.2 72.19 41.9 69.88 29.98 76.65 98.36 29.38 75.75 100 75.8 93.42 71.13 76.68 70.25 31.7 65.13 64.83 63.12 60.33 62.11 63.33 36.53 72.4 66.8 15.02 15.19 67.32 15.39 70.55 64 23.64 68.95 68.15 66.46 35.54 67.88 19.79 69.61 69.5 11.96 68.7 na 68.64 77.89 62.79 66.39 58.57 12.74 7.98 10.18 10.02 11.19 9.5 na 13.25 26.27 10.09 na na 11.16 na 11.84 13.09 4,25 13.12 11.6 6.48 6.38 10.91 5.05 5.73 6.36 2 10.19 7.04 28.86 17.42 na 7.05 7.16 15.53 8.34 10.29 11.68 0.163 0.163 0.163 0.163 0.163 0.163 na 0.163 0.653 0.163 na na 0.163 na 0.163 0.163 0.163 0.163 0.163 0.163 0.163 0.163 0.163 0.163 0.163 0.163 0.163 0.163 1.469 0.163 na 0.163 2.611 0.163 0.163 0.163 0.163 0.163 2-08 1.30 1.66 1.63 1.82 1.55 na 2.16 17.15 1.64 na na 1.82 na 1.93 2.13 0.69 2.14 1.89 1.06 1.04 1.78 0.82 0.93 1.04 0.33 1.66 1.15 42.40 2.84 na 1.15 1.17 2.53 1.36 1.68 | np 6.23 3.90 4.98 4.90 5.47 4.65 na 6.48 51.46 4.93 na na 5.46 na 5.79 6.40 2.08 6.42 5.67 3.17 3.12 5.33 2.47 2.80 3.11 0.98 4.98 3.44 127.19 8.52 na 3.45 3.50 7.59 4.08 5.03 5.71 Page 1 of 1 RFITABLS.xIs EID090466 TABLE 4.4 TRICHLOROETHENE RESULTS FOR GROUNDWATER SAMPLING KCRA FACILITY INVESTIGATION IIUPONT WASHINGTON WORKS PLANT Groundwater Results for November Sampling Groundwater Results for February Sampling M04-MW03 N04-MW02 N05-MW01 P05-MW02 TO6-MW02 P08-MW01 Q04-MW02 Q05-MWOI V05-PWOI V06-MWOI W05-MW01 1/12/98 1/12/9839. 1/13/98800 1/13/98 110 1/13/98400 1/13/9835. 1/13/983. 1/13/98 130 1/18/9822. 1/16/98 150 1/17/9827. MCL= 5 UG/L UG/L I. UG/L UG/L 25 130 UG/L 2. 10 UG/L 10. 50 UG/L UG/L UG/L 5. 25 UG/L UG/L UG/L AA05-MW01 L04-PW01 2/4/99 5. 2/7/99 5. UG/L 5 UG/L , 5 L06-MW01 2/5/99 25. UG/L . 5 M04-MW02 2/7/99 36. UG/L , 5 N04-MW02 2/7/99 30. UG/L . 5 N05-MW01 2/5/99 670. UG/L 10. 50 P05-MW02 2/5/99 150. UG/L 1. 5 P06-MW02 2/5/99 480. UG/L 5. 25 P08-MW01 2/4/99 63. UG/L 1. 5 V05-PWOI 2/7/99 22. UG/L 1. 5 V06-MWOI 2/4/99 120. UG/L 1. 5 W05-MW01 2/6/99 28. UG/L 1. 5 Z,OOOHSV Page 1 of 1 iB^ TABLE 4.5 FREON-113 RESULTS FOR GROUNDWATER SAMPLING RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Groundwater Results for November Sampling GroundwHter Results for February Sampling M04.MW03 11/12/98 1500. UG/L 2. 10 N04-MW02 11/12^8 270. UG/L2. 10 N05-MW01 11/13/987100. UG/L 50, P05-MW02 11/13/98 1400. UG/L 40 P06.MW02 11/13/98 1900 UG/L 20. 100 1'08-MWOI 11/13/98270. UG/L 4. Q04-MW02 11/13/98 860. UG/L 20 100 Q05-MWOI 11/13/982200, IUG/L 50 250 S05-MW02 11/13/98 130 UG/L 2. 10 U04-MWOI 11/12/98 13. UG/L 2. 10 V05-PW01 H'18/9864. UG/L2. 10 MCL= 59,376 UG/L ^ W.EOOOHSV Page 1 of 1 TABLE 4.6 FC-143 RESULTS FOR GROUNDWATER SAMPLING RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Groundwater Results for November Sampling Groundwater Results for February Sampling AA04-MW01 AA05-MW01 AB07-MW02 AC07-MW02 AE11-MW01 A106-MWOI AM07-PW01 E13-MW01 F06-MWOI G17-MWOI K16-PWOI L04-PWOI L06-MWOI L17-PWOI M04-MW02 M04-MW03 M16.MW01 N04-MW02 N05-MW01 N13-MW01 P04-MW02 P05-MW02 P06-MW02 P08-MW01 Q04-MW02 Q05-MWOI ^R04-MW02 S05-MW02 T13-MW01 U04-MW01 V05-PWOI V06-MW01 11/12/980.1 11/11/98 0.77 11/16/98 0.2 11/16/98 0.79 11/10/98 0.41 11/16/98 0.1 11/18/98 1.9 11/11/98 2 11/11/98 0.1 11/11/98 13 11/18/98 0.46 11/18/98 7.9 11/13/98 870 11/18/98 0.33 11/12/98 0.2 11/12/98 0.1 11/10/98 0.86 11/12/98 380 11/13/98 13 11/11/98 0.1 11/12/98 8300 11/13/98 1200 11/13/98 31 11/13/98 36 11/13/98 660 11/13/98 38 11/12/98 1300 11/13/98 690 11/17/98 0.1 11/12/98 1.6 11/18/98 0.66 11/16/98 1.7 UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L UG/L S/.EOOOHSV 0.1 1.1 0.2 0.1 0.1 0.1 0.1 0.1 0.1 > 0.1 1 50 0.1 0.1 0.1 0.1 20 2 0.1 800 100 2 5 50 2 100 50 0.1 0.1 0.1 0.2 T13-MW01 U04-MW01 V05-PWOI V06-MW01 Page 1 of 2 2/3/990.64 2/6/99 4.20 2/7/99 12.4 2/4/991.91 UG/L UG/L UG/L UG/L 0.030 0.033 0.14 0.029 0.1 0.11 0.47 0.095 K^ .BLE4.6 FC-143 RESULTS FOR GROUNDWATER SAMPLING RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Groundwater Results for November Sampling Groundwater Results for February Sampling Preliminary Screening Level (SL): 3 ug/L W05-MW01 Y14-MW01 Z06.MW02 Z07-MW01 209-MW01 2/6/99 0.729 2/2/99 4.95 2/4/99 0.803 2/4/99 2.05 2/6/99 2.74 UG/L 0.028 0.095 UG/L 0.030 0.1 UG/L 0.029 0.097 UG/L 0.028 0.095 UG/L 0.029 0.095 9UOOOHSV Page 2 of 2 TABLK 5.1 OroundwafcT Modal Suamazy DuPont HftMhington Work* Parkcrcburg, Wfc Virginia CM.STATS ---- Varaion 1.3 Calibration Statistics MODI-LOW MODFLOW BCP rila Home....; nod.bcf Target BAS File Ha--... .; Information DOd.ba* Model-Computed Haadaini.a.....<: mod.trg Bod.hdx N11 Hue J08-MW01 Z07-MW02 T13-MW01 D16-HW01 AOOS-MWOl L18-MW01 VOS-tlWOl ASOS-MWOl AX12-MW01 AJ-06-MW01 A008-MW01 004-MW02 Q05-MW01 P06-MW02 poB-vmal M13-MW01 M16-MMOI AA04-MW01 AA05-MW01 AB07-MW02 AC07-MW02' AE11-MK31 AI06-MW01 c" : -."; - S17-MW01 i.'se-w.- M05-MN01 P04-MW02 PC5-MWC2 SOS-MWC2 V06-MWOI M05-MW01 YK-MWO: Z06-MW02 Z07-1W01 ZOS-MW01 yss-w'i'ci AC05-MW01 AL10-MW01 I07-MW01 D08-MW01 FOfi-MWCl U03 -MW01 VaB-tWCZ Tarft Head 561.00 565.40 561.80 562.30 564.SO 558.00 562.90 563.20 566.60 56S.50 563.80 561.20 560.80 560.70 560.80 560.50 553.10 564.00 563.10 564.10 568.40 567,70 569.90 5SS-.2; 557.50 56C.M 560.70 562.10 561.70 560.70 560.50 561.00 560.70 565.30 562.70 565.00 564.60 567.70 566.60 561.70 562.90 562.80 555.30 554.30 Nodcl Bed 561.73 S62.97 559.97 559.83 567.30 557.87 560.49 565.76 566.26 568.68 566.89 561.29 560.93 561.20 560.69 559.45 558.42 563.85 563.95 564.21 564.92 564.93 568.54 553.8; 558.26 562.36 561.90 561.97 561.82 559.88 558.66 558.82 561.35 562,44 562.61 562.36 561.99 565.15 567.45 562.42 562.97 563.34 556.97 555.60 Rwldual -0.73 2.43 1.83 2.47 -2.40 0.13 2.41 -2.56 0.34 -0.18 -3.09 -0.09 -0.13 -0.50 0.11 1.05 0.68 0.15 -0.85 -0.11 3.48 2.77 1.36 -:.5: -0.76 -l."6 -1.20 0,13 -0.12 0.82 1.84 2.18 -0.65 2.86 0.09 2.64 2.61 2.55 -0.85 -0.72 -0.07 -0.54 -1.67 -1.30 EID090476 ---- Summary Statistics or Xabir* Kodl Number of Targets 44 Residual Mean 0.321549 Residual Standard Dev. m 1.599567 Residual Sum of Squares 117.128311 Absolute Residual Mean 1.266028 Minimum Residual -3.089648 Maximum Residual . 3.480383 Observed Range in Head - 15.600000 Res. Std. Dev./Range 0.102536 EID090477 TABLE 5.2 Groundwater Model Summary DuPont Washington Works Parkersburg, West Virginia Sensitivity Aniayses Residua) Mean Residual Standard Deviation Residual Sum of Squares Absolute Residua! Mean Minimum Residual Maximum Residual Recharge + 86% -3.1 1.7 556 3.1 -5.6 0,7 Recharge-66% 2.7 1.9 480 3.0 -2.1 5.6 Conductivity * 50% -1.2 1.8 202 1.8 -6.3 2.8 Conductivity-50% 4.7 3.8 1658 5.1 -2.3 14.5 Conductance 5% -0.6 1.6 128 1.5 -3.9 2.7 Conductance - 5% 1.3 1.6 193 1.7 -2.2 4.4 River Stage + 2 feet -1.9 1.6 270 2.1 -5.1 14 River Stage 2 feet 2.6 1.6 408 2.7 -1.0 5.6 | Pumping +15 % 5.2 2.0 1358 5.2 0.0 8.3 Pumping-15% -4.2 1.7 913 4.2 -7.6 -0.3 Residual = Observed Head minus Modeled Head residual = modeled heads too high + residual = modeled heads too low Note: Model units are in feet and days. Page 1 of 1 Sensitivity xls EID090478 TABLE 6.1 BURNING GROUND SOIL ANALYTICAL RESULTS; 0 - 2 FEKT SRCNAME Depth Date AA06-SB01 From To 0 2 9/2/98 AA07-SB01 0 2 9/16/98 AA07-SB02 0 2 9/27/98 AA08-SB01 0 2 9/27/98 AA08-SB02 0 2 9/27/98 AB07-SB02 0 2 9/4/98 AB08-SB01 ABOB-SB02 0 2 9/27/98 AC06-SB03 0 2 8/31/98 AC06-SB04 0 2 9/1/98 AC06-SB05 0 2 9/9/98 AC07-SB02 0 2 9/9/98 AC07-SB03 0 2 9/14/98 AC07-SB04 0 2 9/14/98 AC08-SB01 0 2 9/27/98 AC08-SB02 0 2 8/24/98 Y07-SB01 0 2 9/22/98 Z06-SB03 0 2 9/15/98 Z06-SB04 0 2 9/11/98 Z07-SB01 0 2 9/10/98 Maximum Concentration Industrial Soti SL (CR- 10-8: HQ 1) Maximum Cone. Exceeds SL? Carbon Tetrachlorlde ug/kg Qua) PQL ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 270 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 NO 240 ND 240 ND 240 ND 240 ND 240 NO 44000 c No FC-143 ug/kg Qua! Ul Ul 82 32 U U Ul U U 15 U 39 64 29 Ul 53 U Ul Ul Ul 82 120000 (1) No POL 24 25 12 11 12 12 37 12 10 13 11 11 11 12 21 11 11 26 26 22 Arsenic mg/kg Qua) 8 7.4 5.6 9.8 8.7 9.4 10.2 3.7 11.7 8 5.2 5.2 0.2 7.5 6.9 4.9 10.2 5.9 12.7 12.7 3.8 C Yes Barium mg/kg Qua) 167 108 142 112 106 72 79 43 42 41 562 270 131 139 142 212 78 124 71 562.0 140000 n No Cadmium mg/kg Qua! ND 0.59 J 0.67 J 1.04 J 1.99 J 1.2 J PQL 2.3 2.6 2.2 2.2 2.3 2.2 0.92 J 2.3 ND 2 ND 2.2 ND 2.1 0.74 J 2.6 ND 2.2 ND 2.2 0.71 J 2.2 0.59 J 2.2 0.65 J 2.3 O.B9 J 2.3 N0 2.3 ND 2.2 2.0 1000 n No mg/k 10. 11. 11. 26 19. 10. 14. 5.8 10. 9.7 9.7 11. 11. 10. 12. 3 8.4 12 14 26 100 No Legend: c = Carcinogen. CR 'Target cancer risk for carcinogenic effects. HQ a Target hazard quotient for noncancer effects. J = Estimated concentration below the PQL n = Noncarcinogen. ND = Not Detected. PQL = Practical QuantXatton Limit. Qua! s Laboratory data qualifier (J. U. Ut) or Not Detected (NO) SL Screening Level. EPA Region III risk-based concentrations (RBCs) for industrial SON. based on 1 in 1 million (10 ) excess cancer risk and noncancer hazard quotient of 1. U "Not detected. Ul - Not detected. Notes; (1) Preliminary screening level: see Table 6.6 and Section 6.4.2 (2) Conservative SL for lead in industrial soil. see Section 64.1 r :n III 11 l\l 08EOOOHSV TA>L,E 6.2 BURNING GROUND SOIL ANALYTICAL RESULTS: 2 - 20 FEt. F SRCNAME AAO&-SB01 AA06-SB01 AAQ6-SB01 AA07-SB02 AA08-SB01 AB06-SB01 AB06-SB01 AB06-SB01 AB06-SB02 AB06-SB02 AB06-SB02 AB07-SB02 AB07-SB02 AB07-SB02 AB07-SB02 AB06-SB02 AC06-SB03 ACOS-SB03 AC06-SB04 AC06-SB04 AC06-SB05 AC06-SB05 AC06-SB05 AC07-SB02 AC07-SB03 AC07-SB03 AC07-SB03 AC07-SB03 AC07-SB04 AC07-SB04 AC07-SB04 AC07-SB04 AC08-SB01 AC08-SB01 AC08-SB01 AC08-SB01 AC08.SB02 AC08-SB02 Depth Prom To 6 8 14 16 20 22 4 6 4 6 4 6 10 12 18 20 2 4 10 12 18 20 4 6 10 12 14 18 20 22 4 6 6 8 12 14 6 8 14 16 6 8 12 - 14 18 20 18 20 4 6 8 10 14 16 20 22 4 6 10 12 14 16 20 22 4 6 8 10 14 16 20 22 10 12 20 22 Date 9/2/98 9/2/98 9/2/98 9/27/98 9/27/98 9/1/98 9/1/98 9/1/98 9/8/98 9/8/98 9/8/98 9/4/98 9/4/98 9/4/98 9/4/98 907/98 8/31/98 8/31/98 9/1/98 9/1/98 9/9/98 9/9/98 9/9/98 9/9/98 9/14/98 9/14/98 9/14/98 9/14/98 9/14/96 9/14/98 9/14/98 9/14/98 9/27/98 9/27/98 9/27/98 9/27/98 804/98 8/24/98 Carbon Tetrachloride ug/kg Qua! PQL NO 240 NO 240 ND 240 NO 240 NO 240 NO 250 NO 260 NO 270 NO 230 NO 270 NO 240 330 260 840 250 230 J 390 N0 290 N0 250 N0 240 N0 240 N0 240 ND 240 ND 240 N0 240 N0 240 N0 240 ND 240 N0 240 ND 240 ND 240 ND 240 ND 240 N0 240 FC-143 Arsenic Barium Csdnilufii ug/kg Qua) PQL mg/kg dual mgflcg Qual mg/kg Qua) PQL m 140 14 12.3 52 NO 2.3 51 12 9.8 26 ND 2.2 U 11 9 28 NO 2.1 91 12 10.5 59 0.78 J 2.3 U 12 9.8 116 0.81 J 2.3 UI 24 9.7 43 ND 2.3 UI 22 10.3 35 N0 2.2 UI 21 6.1 23 ND 2.1 U 12 10.7 48 N0 2.2 17 11 10.1 37 N0 2.2 U 11 10.2 35 ND 2.1 U 12 10 43 N0 2.3 36 13 11.8 55 ND 2.4 59 12 8.3 36 N0 2.3 U 11 4.4 30 N0 2.1 11 10 7 150 0.76 J 2.3 55 12 11.7 44 ND 2.4 12 12 12 63 N0 2.2 63 12 11.1 55 ND 2.4 UI 22 8.5 44 ND 2.1 U 12 10.5 46 ND 2.3 U 11 8 38 ND 2.3 U 11 5.9 21 ND 2.1 U 12 13 56 N0 2.5 U 12 UI 23 11.4 76 18 13 ND 2.5 U 11 8.8 43 U 13 ND 2.1 13 11 7.8 45 U 12 ND 2.3 U 12 6 39 ND 2.1 UI 35 UI 25 10.9 90 0.88 J 2.S U 11 UI 23 U 12 3.5 U 10 5.9 63 ND 2.4 48 0.23 J 2.1 < I'rKt n^-uTt^ l;iht<i.\l !*..' K'r'U*!! \\1 I8EOOOHSV TABLE 6.2 Bl'RNIM; GROUND SOIL ANALYTICAL RESULTS: 2 - 20 FEt.T SRCNAME Depth Y07-SB01 From To 4 6 Y07-S801 8 10 Y07-SB01 14 16 Z06-SB02 2 4 Z06-SB02 8 10 Z06-SB02 14 16 Z06-SB02 20 22 Z06-SB03 4 6 Z06-SB03 Z06-SB03 Z06-SB03 10 12 14 16 20 22 Z06-SB04 10 12 Z06-SB04------ 20 22 Z07-SB01 10 12 Z07-SB01 20 22 Z09-SB01 2 4 Z09-SB01 8 10 Z09-SB01 Z09-SB01 14 16 20 22 Maximum Concentration Industrial Soil SL (CR = TO-6; HQ = Maximum Cone. Exceeds SL? Date 9/22/98 9/22/98 9722/98 9/22/98 9/22/98 9/22/98 9/22/98 9/15/98 9/15/98 9/15/98 9/15/98 9/11/98 9/11/98 9/10/98 9/10/98 9/3/98 9/3/98 9/3/98 9/3/98 1) Carbon Tetrachloride ug/kg Qual POL 180 J 240 ND 240 ND 240 NO 240 NO 240 NO 240 NO 240 ND 240 NO 240 ND 240 ND 240 840 44000 c No Lagand- c = Carcinogen. CR "Target cancer risk for careinogwic effects. HQ Target hazard quotient for noncancer affects. J Estimated concentration below the PQL n Noncardnogen. ND Not Detected. PQL = Practical Quantitalion Limit. Qual a Laboratory data qualifier (J. U, UI) or Not Detected (ND). SL = Screening Level. EPA Region III risk-based concentrations (RBCs) Vfi industrial soil. based on 1 in 1 million (104) excess cancer risk and noncancer hazard quotient of 1. U = Not detected UI Not detected FC-143 Arsenic Barium Cadmium ug/kg Qual PQL mg/kg Qua) mgflcg Qual mg/kg Qua) POL m U 11 U 13 10.5 46 0.61 J 2.3 78 11 U 12 12.2 71 0.71 J 2.4 23 13 6,7 50 0.54 J 2.4 U 10 U 12 UI 21 UI 22 8.7 UI 21 4S 0.41 J 2.2 UI 21 59 13 10 44 U 11 NO 2.3 UI 24 9 43 U 10 7 27 NO 2.3 NO 2 34 12 12.5 65 NO 2.4 U 12 12 59 NO 2.5 U 12 10.4 65 NO 2.4 U 11 8.2 41 NO 2.2 140 13 150 0.88 120000 (1) No 3.8 C 140000 n 1000 n Yes No No Notes.: (1) Preliminary screening level: see Table 6.6 and Section 6.4.2. (2) Conservative SL for lead in industrial soil: see Section 6.4 1. s I'rri 44tkNm TJ II liiHti. \1-. I (...^ 1. ^K *)<> 1(1 11 A\1 moooHSV ''Vaf 1 E6J RIVER BANK LANDFILL/ ANAEROBIC DIGESTION PONDS SOIL ANALYTICAL RESULTS: 0 2 FEET SRCNAME Depth AA04-SB01 From To 0 2 AA05-SB01 0 2 AC04-SB01 0 2 AE05-5B02 0 2 AF05-SB01 0 2 AH05-SB01 0 2 AID6-SB01 0 2 K04-SB01 0 2 L04.SB01 0 2 L06-SB01 0 2 M04-SB02 0 2 M04-SB03 0 2 M04-SB04 0 2 N04.SB01 0 2 N04-SB02 0 2 004-SB02 0 2 004-SB03 0 2 P04-SB02 0 2 Q04-SB03 0 2 R04-SB02 0 2 S04-SB02 0 2 T04-SB01 U04-SB01 0- 2 0 2 V04-SB01 0 2 Y04-SB01 0 2 Maximum Concentration Industrial Soil SL (CR 1M; HQ = 1) Maximum cone. exceeds SL? Date 8/20/98 9/23/98 8/21/98 8/22/98 8/22/98 10/14/98 8/23/98 10/12/98 10/12/98 9/25/98 10/10/98 10/10/98 10/12/98 10/12/98 10/9/98 10/11/98 10/12/98 10/9/98 10/11/98 10/9/98 10/11/08 10/10/98 9/30/98 9/29/98 8/20/98 ug/hg FC.143 Qua! U Ul PQL 12 27 FREON 113 ug/kg Qual POL NO 520 NO 510 22 11 ND 530 Ul 22 NO 530 40 14 ND 590 14 12 NO 500 35 12 ND 520 Ul 35 NO 440 Ul 22 ND 470 55 12 ND 500 Ul 24 ND 530 81 12 1600 J 470 Ul 25 ND 560 79 13 ND 780 34 12 ND 600 32 11 ND 480 50 13 NO 530 170 13 ND 630 9500 1300 NO 560 1100 130 ND 650 60 11 170 J 600 140 13 ND 560 600 59 N0 610 22 14 ND 540 9500 1600 120000 (1) 6.1E+10 n No No Methytene Chloride ug/kg Qual POL NO 260 ND 260 ND 260 NO 270 ND 300 ND 250 ND 260 ND 220 ND 230 NO 250 ND 270 ND 240 NO 280 ND 390 NO 300 NO 240 ND 270 NO 320 ND 280 ND 320 NO 300 ND 280 NO 300 ND 270 NO 760000 C No CR = Target cancer risk for carcinogenic effacts. ' HQ = Target hazard quotient for noncancer effects. J = Estimated concentration below the PQL n - Noncarcinogen NO - Not Detected PQL = Practical Quantitation Limit Qual = Laboratory'data qualifier (J, U. Ul) or Not Detected (ND). SL = Screening Level EPA Region III risk-based concentrations (RBCs) for industrial soil, based on 1 in 1 million (104) excess cancer risk and noncancer hazard quotient of 1. U = Not detected Ul Not detected Notes; (11 Preliminary screening level; see Table 6 6 and Section 6.4.2. (2) Conservative SL for lead in industrial soil; see Section 6.4.1. S 11'ritJ4tilKw7'<lt.|a|tU,. )s KrI^i^Xwrifl 13 AM TetracMoro ug/kg Q N N N 510 N N N N N N N N N N 69 N N N N N N N N N 510 110000 No 8OOOHSV vs^ '^^S-y^-j . JE.63 RIVER BANK LANDFILL/ ANAEROBIC DIGESTION PONDS SOIL ANALYTICAL RESULTS: 0 - 2 FEET SRCNAME Depth Date AA04-SB01 AA05-SB01 From To 0 2 0 2 800/98 9/23/98 AC04-SB01 0 2 8/21/98 AE05-SB02 0 2 8/22/98 AF05-SB01 0 2 8/22/98 AM05-SB01 0 2 10/14/98 AI06-SB01 0 2 8/23/98 K04-SB01 0 2 10/12/98 L04-SB01 0 2 10/12/98 L06-SB01 0 2 9/25/98 M04-SB02 0 2 10/10/98 M04-SB03 0 2 10/10/98 M04-SB04 0 2 10/12/98 N04-SB01 0 2 10/12/98 N04-SB02 0 2 10/9/98 004-SB02 0 2 10/11/98 004-SB03 0 2 10/12/98 P04-SB02 0 2 10/9/98 Q04-SB03 0 2 10/11/98 R04-SB02 0 2 10/9/98 S04-SB02 0 2 10/11/98 T04-SB01 " 0 2 10/10/98 U04-SB01 V04-SB01 0 2 0 2 900/98 909/98 Y04-SB01 0 2 8/20/98 Maximum Concentration Industrial Soil SL (CR = 104; HQ = 1) Maximum cone. exceeds SL? Legend: CR = Target cancer risk for carcinogenic effects. HQ = Target hazard quotient for noncancer effects. J = Estimated concentration below the PQL. n = Noncarcinogen. ND = Not Detected. PQL = Practical Quantitation Limit. Qilal " Laboratory data qualifier (J. U, Ul) or Not Detected (ND) SL = Screening Level. EPA Region III risk-based concentrati (RBCs) for industrial soil. based on 1 in 1 million (10^) excess cancer risk and noncancer hazard quolioiit of 1 U = Not detected Ul = Not detected Notes; (1) Preliminary screening level: see Table 6 6 and Section 642. (2) Conservative SL for lead in industrial soil: see Section 6.4 1 Arsenic mgfkg Qual 7.7 10.8 9.4 5.9 15 7.9 5.9 6.9 6.4 9.6 7.8 9.7 10.2 7.8 9.7 10.5 6.4 9.50 10.1 7.50 10.4 10 8.2 6.7 9.2 15 3.8 C Yes Barium mg/kg 144 Qua! 85 92 972 131 85 129 172 135 123 224 288 157 104 161 270 120 175 127 150 160 149 139 153 139 972 140000 n No Cadmium mg/kg Qua) ND 0.51 J ND PQL 2.4 2.3 2.1 4.5 2.1 7.4 2.3 2.34 J 2.4 3.1 0.7 0.91 0.36 0.3 1 0.42 0.58 3 3.3 2.2 ND 2.2 J 2.3 J 2.3 ND 2.2 N0 2.4 J 2.4 J 2.3 ND 2.3 J 2.4 ND 2.2 ND 2.4 J 2.4 ND . 2.5 J 2.7 ND 2.4 2.2 2.3 ND 2.3 7.4 1000 n No ' I'"" .Milliii, ?; ii l.ihir ,1. li. li.arnni|;.lM Load mg/kg Qu 19 15.4 13.4 33 19 26 42 29 20.1 16.2 18.7 24.2 60 33 9.8 49 13.5 61 77 28 80 50 29 32 50 80 1000 (2 No WOOOHSV SRCNAME AA04-SB01 AA04-SB01 AA05-SB01 AA05-SB01 AA05-SB01 AA05-SB01 AC04-SB01 AC04-SB01 AE05-SB02 AF05-SB01 AF05-SB01 AH05-SB01 A106-SB01 K04-SB01 L04-SB01 L06-SB01 M04-SB02 M04-SB02 M04-SB03 M04-SB03 M04-SB04 M04-SB05 M04-SB05 M04-SB05 M06-SB02 M06-SB02 M06-SB02 N04-SB01 N04-SB02 N04-SB02 N05-SB01 N05-SB01 N05-6B01 004-BB02 004-SB02 004-SB03 004-SBQ3 Depth From To 6 8 14 16 4 6 8 10 16 18 20 22 10 12 20 22 10 12 10 12 20 22 4 6 18 20 12 14 8 10 10 12 8 10 14 16 6 8 14 16 10 12 2 4 6 8 12 14 2 4 8 10 20 22 12 14 8 10 14 16 2 4 8 10 20 22 6 8 14 16 10 12 14 16 1. _E6.4 RIVKR BANK IANDFILI-/AEROBIC DIGESTION PONDS SOU. ANALYTICAL RESULTS: 2-20 FEET Date 8/20/98 8/20/98 9/23/98 9/23/98 9/23/98 9/23/98 8/21/98 8/21/98 8/22/98 8/22/98 8/22/98 10/14/98 8/23/98 10/12/98 10/12/98 9/25/98 10/10/98 10/10/98 10/10/98 10/10/98 10/12/98 10/12/98 10/12/98 10/12/98 9/28/98 9/28/98 9/29/98 . 10/12/98 10/9/98 10/9/98 9/28/98 9/28/98 9/28/98 10/11/98 10/11/98 10/12/98 10/12/98 ug/kg 32 20 39 20 18 34 280 26 34 86 45 43 44 32 220 110 1800 28 24 FC.143 Qua) UI U1 U1 U U U U U1 U1 U1 U U1 U U1 U U U1 U PQL 11 24 12 12 21 11 12 13 13 13 12 15 11 24 24 66 25 13 12 24 12 12 12 12 11 11 11 . 25 12 12 11 11 210 20 13 12 12 FREON 113 Mothyloir ChloricfB T ug/kg Qual POL iigfkg Qual PQL u NO 490 ND 240 NO 570 ND 290 ND 530 ND 260 ND 630 ND 320 1 ND 560 NO 280 340 340 1600 1600 1600 380 580 330 190 140 ND 650 NO 480 J 520 ND 500 580 ND 500 ND 530 J 510 J 490 J 500 ND 500 650 ND 500 320000 N0 620 230 J 570 ND 550 510 ND 550 ND 500 N0 500 ND 570 730 ND 480 J 530 J 510 ND 550 ND 500 J 520 ND 330 NO 240 ND 260 ND 2SO NO 290 NO 250 NO 260 NO 260 NO 250 NO 2SO 2SO 10000 J 310 NO 280 NO 280 NO 290 NO 280 NO 250 NO 250 290 N0 240 N0 270 N0 2SO N0 280 N0 250 ND 260 SirM.44.|l)ln.HIIV|>M].shiH>-4^;llWlll HAM S8EOOOHSV V '.6.4 RIVER BANK LANDFILL/c.ROBIC DIGESTION PONDS SOU. ANALYTICAL RESULTS: 2-20 FEET SRCNAME Depth P04-SB02 From To 8 10 P04-SB02 P05-SB02 14 16 2 4 Q04-SB03 8 10 R04-SB02 R04-SB02 S04-SB02 10 12 18 20 8 10 S04-SB02 18 20 S05-SB02 2 4 S05-SB02 10 12 T04-SB01 10 12 T04-SB01 16 18 U04-SB01 4 6 U04-SB01 16 18 V04-SB01 4 6 V04-SB01 Y04-SB01 18 20 10 12 Y04-SB01 18 20 Maximum Industrial SON SL (CR 104; HQ 1) Maximum cone. Exceeds SL? Date 10/9/98 10/9/98 9/24/98 10/11/98 10/9/98 10/9/98 10/11/98 10/11/98 9/26/98 9/26/98 10/10/98 10/10/98 9/30/96 9/30/98 9/29/98 9/29/98 8/20/98 6/20/98 FC.143 ug/kg 11000 10000 20 48000 7900 11000 dual 44000 11000 ' 28 140 U 54 95 U 170 UI UI U 48000 120000 (1) No POL 1300 1300 12 3800 1300 1300 3800 1300 11 13 12 13 12 13 13 27 24 13 FREON 113 ug/kg Qua! N0 N0 N0 ND N0 N0 ND N0 ND ND ND ND ND ND ND ND ND PQL 590 560 510 550 540 590 500 520 480 520 600 540 540 670 500 580 560 1600 6.1E+10 n No Methytene Chtorkto ug/kg Qunl ND POL 290 ND 280 ND 260 ND 280 ND 270 ND 290 ND 250 ND 260 ND 240 NO 260 ND 300 NO 270 ND 270 ND 330 ND 250 NO 290 NO 280 320000 760000 c No Tetra ug/kg 1200 1400 11000 No Leoapd: CR s Target cancer risk for carcinogenic effects. HQ = Target hazard quotient for noncancer effects. J = Estimated concentration below the POL n x Noncarcinogen. NO = Not Detected. PQL " Practical Quantitation Limit. Qual = Laboratory date qualifier (J. U, UI) or Not Detected (ND). SL = Screening Level. EPA Region III risk-based concentrations (RBCs) for Industrial SON. based on 11n 1 million (104) [excess cancer risk and noncancer hazard quotient of 1. U h Not detected. UI Not detected. MV9fl0fmSmS. (1) Preliminary screening level; see Table 6.6 and Section 6.4.2 (2) Conservative SL for lead in industrial soil; see Section 6.4.1. S ll'rrM.1111--72 HT>M(& xh H..4'<. 2wr 111 11 <M 98SOOOHSV SRCNAME AA04-SB01 AA04-SB01 AA05-SB01 AA05-SB01 AA05-SB01 AA05-SB01 AC04-SB01 AC04-SB01 AE05-SB02 AF05-SB01 AF05-SB01 AH05-SB01 AI06-SB01 K04-SB01 L04-SB01 L06-SB01 M04-SB02 M04-SB02 M04-SB03 M04-SB03 M04-SB04 M04-SB05 M04-SB05 M04-SB05 M06-SB02 M06-SB02 M06-SB02 N04-SB01 N04-SB02 N04-SB02 N05-SB01 N05-SB01 N05-SB01 004-SB02 004-SB02 004-SB03 004-SB03 Depth From To 6 6 14 16 4 6 8 10 16 18 20 22 10 12 20 22 10 12 10 12 20 22 4 6 18 20 12 14 8 10 10 12 8 10 14 16 6 8 14 16 -10 12 2 4 6 8 12 14 2 4 8 10 20 22 12 14 8 10 14 16 2 4 8 10 20 22 6 8 14 16 10 12 14 16 T. 6.4 RIVER BANK LANDFILL/AEROBIC DIGESTION PONDS SOIL ANALYTICAL RESULTS: 2-20 FEET Date 8/20/98 8/20/98 9/23/98 9/23/98 9/23/98 9/23/98 8/21/98 8/21/98 8/22/98 8/22/98 8/22/98 10/14/98 8/23/98 10/12/98 10/12/98 9/25/98 10/10/98 10/10/98 10/10/98 10/10/98 10/12/98 10/12/98 10/12/98 10/12/98 9/28/98 9/28/98 9/29/98 10/12/98 10/9/98 10/9/98 9/28/98 9/28/98 9/28/98 10/11/98 10/11/98 10/12/98 10/12/98 Trichloreethene ug/kg dual POL NO 240 ND 290 Arsenic mg/kg Qua! 6.7 5.2 Barium mg/kg Qua! 157 106 Cadmium mg/kg Quid NO NO POL 2.4 2.5 NO 260 7.9 27 0.23 J 2.2 2200 320 3.8 22 0 21 J 2.1 NO 280 7.4 155 ND 2.5 1400 8800 78 340 NO 330 NO 240 ND 260 NO 250 290 ND 250 ND 260 N0 260 ND 250 ND 250 ND 250 ND 250 ND 310 ND 280 N0 280 N0 260 ND 280 ND 250 ND 290 290 J 240 270 ND 250 ND 280 ND 250 N0 260 13.4 7.9 8.1 7.3 9 8.7 6.7 6.4 7.4 6.8 22 6.2 5.8 6 8 5.2 5.8 7 5.9 8.2 7.8 5.2 7.3 7.3 6.9 6.8 145 1.94 J 2.9 62 2.7 2.2 140 ND 2.5 148 N0 2.5 157 11.8 2.5 233 ND 2.5 142 ND 2.5 136 ND 2.4 130 ND 2.4 146 N0 2.3 122 0.33 J 2.3 180 N0 2.5 134 ND 2.5 38 0.24 J 2.1 35 0.28 J 2.2 33 1.4 J 2.1 137 ND 2.5 229 ND 2.5 102 ND 2.5 147 0.7 J 2.3 43 0.29 J 2.2 32 0.33 J 2.2 178 ND 2.4 108 0.24 J 2.5 146 ND 2.5 144 ND 2.4 mfl 1 8. 7 4. 13 9 13 17 15 11 18 12 14 15 14 1 17 1 6 8 4 14 1 10 9 6 1 1 1 1 ,s rr.J|,ll^7211' lallllr.l- llrfoJH I" III 11 AM Z.8EOOOHSV ^ T E6.4 RIVER BANK LANDFILL/AEROBIC DIGESTION PONDS SOU. ANALYTICAL RESULTS; 2-20 FEET SRCNAME Depth P04-SB02 Frwn To 8 10 P04-SB02 14 16 P05-SB02 2 4 Q04-SB03 8 10 R04-SB02 10 12 R04-SB02 S04-SB02 18 20 8 10 S04-SB02 18 20 SO&-SB02 2 4 S05-SB02 10 12 T04-SB01 10 12 T04.SB01 16 18 U04-SB01 4 6 U04-SB01 16 18 V04-SB01 4 6 V04-SB01 Y04.SB01 Y04^B01 18 20 10 12 18 20 Maximum Industrial Soil SL (CR * 10-6; HQ = 1) Maximum cone. Exceeds SL? Date 10/9/98 10/9/96 9/24/98 10/11/98 10/9/98 10/9/98 10/11/98 10/11/98 9/26/98 9/26/98 10/10/98 10/10/98 9/30/98 9/30/98 9/29/98 9/29/98 8/20/98 8/20/98 Trichtoroethane ug/kg Quat POL ND 290 NO 280 NO 260 ND 280 NO 270 NO 290 NO 250 ND 260 ND 240 ND 260 ND 300 ND 270 ND 270 ND 330 NO 250 ND 290 ND 280 8800 520000 c No Arsenic ing/kg Qual 6.80 8.60 6.90 7.6 7.50 7.40 10.5 8.3 5.1 7.8 5.9 6.2 7.3 6.6 6.6 7.1 6 22 3.8 c Yes Barium mg/kg 172 Qual 170 830 171 180 186 187 193 91 30 195 187 162 155 212 128 117 830 140000 n No Cadmium mg/kg Qual NO NO POL 2.6 2.6 NO 2.5 NO 2.S ND 2.6 NO 2.4 NO 2.5 0.91 J 2.1 0.63 J 2.3 NO 2.5 ND 2.5 2.5 2.3 2.55 J 2.6 2.8 2.S 2.35 J 2.6 N0 2.4 118 1000 n No Loqend: CR = Target cancer risk for carcinogenic effects. HQ a Target hazard quotient for noncanoer effects. J = Estimated concentration below the PQL n = Noncarcinogen. ND Not Detected. POL = Practical Quantttaton Limit. Qual = Laboratory data qualifier (J. U, Ul) or Not Detected (N SL * Screening Level EPA Region III risk-based concentrat (RBCs) for industrial soil. based on 1 in 1 million dO4) excess cancer risk and noncancer hazard quotient of 1. U = Not defected. Ul = Not dejtected. Noff: (1) Preliminary screening level: see Table 6.6 and Section 64 (2) Conservative SL for lead in industrial soil: see Section 6.4.1 L mo/k 22 17.5 7.8 18.1 16.1 15.8 18.7 16.4 6.7 7.7 17.9 13 18 14 16.2 14.4 10.1 114 1000 No \ l'WHtll'I: ]1< Ullln \1< II"! hI.'U'WIII 1> \M 88COOOHSV TAKLE6.S PRODUCTION WELL GROUNDWATER CONCENTRATIONS COMPARED TO MCLs OR OTHER SCREENING CRITERIA SRCNAME Date K16-PW01 11/18/98 K16-PW01 2/9/99 L17-PW01 11/18/98 L17-PW01 3/9/99 AM07.PW01 11/18/98 AM07-PW01 2/7/99 V05-PW01 11/18/98 V05-PW01 2/7/99 L04-PVTO1 11/18/98 L04-PW01 2/7/99 Maximum Concentration MCL or Other Criterion Maximum cone. Exceeds Criterion? Arsenic mg/L 00013 ND 0.0043 NO 0.01 ND 0.0025 0.0017 0.0068 0.0028 0.01 0.05 No Qua! J J J J J J MCL POL 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Barium mg/L 0.15 0.14 0.13 0.13 0.0672 0,0743 0.0845 0.0848 0.16 0.14 0.16 2 No Qual J J J J MCL PQL 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Cadmium Qual mg/L ND ND ND ND ND ND ND ND ND ND ND 0.005 MCL No PQL 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Lead mg/L ND r-0 O.OU22 NO NO NO ND ND ND NO 0.0022 0.015 Na Qual J (1) PQL 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 Nicke men ND ND ND ND ND ND ND ND ND ND ND 0.14 No SRCNAME Date K16-PW01 11/18/98 K16-PW01 2/9/99 L17-PW01 . 11/18/88 L17-PW01 2/9/99 AM07-PW01 " 11/18/98 AM07-PW01 2/7/99 V05-PW01 11/18/98 V05-PW01 217199 L04-PW01 11/18/98 L04-PW01 217199 Maximum Concentration MCL or Other Criterion Maximum cone. Exceeds Criterion? FC-143 ug/L 0.46 16.2 0.33 2.76 1.9 0.082 0.66 12.4 7.9 5.89 16.2 3 Yes Qual J (2) PQL 0.1 1 0.1 0.098 0.1 0.1 0.1 0.47 1 0.094 PCE ug/L ND ND 4 5 4 4 5 5 No Qual PQL 5 5 J 5 5 J 5 J 5 MCL TCE ug/L Qual PQL ND 5 ND 5 22 5 22 5 5 5 5 J 5 22 5 MCL Yes MCI ug/L ND ND ND NO NO NO NO NO NO ND ! No J =|Estimaledvalue below PQL. MCL. = Federal maximum contaminant Level (or drinking water. ND'= Not detected. PQL = Practical quanlttation limit Plant potabte water supply (well 336). Observed concentrations did not exceed screening levels. (1) Federal action level for lead in tap water. (2) Preliminary screening level: we Table 6.6 and Section 6.4 2. (3) Risk-based concentration for Freon 113 (1.1.2-trichtoro-1,2.2-trHluoroethaiw in tap water (USEPA Region III. 1999) Qual MCL PQL 5 5 5 S 5 5 5 5 5 5 Fi*on1 Uflfl NO NO 64 56 270 270 5900 No S .IWh44it-7HW fMl: l>,ll,.<W;M> 111)4 AM ^OOOHSV TABLE 6.6 CALCULATION OF PRELIMINARY SCREENING LEVELS FOR FC-143 IN SOIL AND DRINKING WATER CEGair (1) malm's 0.0003 Inhalation Rate (2) ins/day 20 Allowable Dally lntak(3) mg/day 0.006 Water Ing--tion Rate (4) Uday 2 PSL water W mg/L 0.003 Soil Ingutlon RateW mg/day 50 Conversion Factor mB/kg 1.E+06 PSL oil (7) walks 120 Allowable Daily Intake = CEGair x Inhalation Rate PSL water* Prelin^aryScrBe^ngLfi^l for drinking waters Allowable Daily Irttake/Water ingstion Rate PSL soil = Preliminary Screening Level for Industrial coil = Allowable Daily Intake x 104* mg/kg / Soil Ingeation Rate Mtttea (1) CEGair e Community Exposure Guideline for air exposures (Haakelt Laboratory. 1991). (2) USEPA Region HI default residential inhalation rate (USEPA Region III. 1999). (3) Allowable Daily Intake = CEGair x Inhalation Rate. (4) USEPA Region III default residential groundwater ingestion rate (USEPA Region III. 1999). (5) PSL water a Allowable Daily Intake / Water Ingestion Rate. (6) USEPA default industrial soil ingestion rate {USEPA region III, 1999). (7) PSL soil = Allowable Daily Intake x mg/kg / Soil Ingestion Rate. s t**a jjdx.k": b Tflok \( tth^ 9 :)> * li'i > 4 w Page I ol" I EID090489 Tauie 6.7 RISK-BASED SCREENING FOR SOIL Constituent Arsenic Barium Cadmium Lead Nickel Carbon Telrachlorkte FC-143 Freon 113 Methylene Chloride Tetrachloroethylene Trichloroethylene Maximum Detected Concentration, mg/kg BG BG RBL/ADP RBL/ADP 0-2fl 127 562 2-20 ft 13 150 0-2(t 15 972 2-20ft 22 830 2 0.88 7.4 11.8 26 17 80 114 17.3 NO (<0.24) 0.082 22.6 0'84 0.14 46.3 9.5 1.6 ND (<0.3) 44.6 48 1.6 320 - 0.51 1.4 0.16 8.8 Industrial Soils'. mg/kg (1) Max > Soil SL? 3.8 140000 AllSWMUs No 1000 No 1000 (2) No 4100C No 44 No 120 (3) No 6.10E+07 No 760 No 110 No 520 No Legend: - Not analyzed. na a not available. BG Burning Ground. RBL/AOP = Riverbank Landfill and Anaerobic Digestion Ponds SL = Screening Level Nfitesi (1) Industrial soil SL = Risk-based concentration (RBC) for industrial soil. (2) Conservative SL for lead in industrial soil; see Section 6.4.1. (3) Preliminary screening level, see Table 6.6 and Section 6.4.2. USEPA Region III 1999. < ' r>'M4l>72 ll<\1lhlr< <hVr<>-7Ui/2<MI H AM I6EOOOHSV TABLE 6.8 HEALTH-BASED SCREENING FOR PRODUCTION WELL WATER Comtfbrnt Arsenic Barium Cadmium Lead Nickel PC-143 Tetrachloroethylene Unite mg/L mg/L mg/L mg/L mg/L ug/L ug/L Potable Water Wall(l) 0.01 0.07 ND(<0.01) N0(0.003) NO (<0.05) 1.9 NO (<5) wur ff*^y^c.j--,--^-- >n>a*..- Waited) Scr--ning Lavl Type Max>SL7 0.0068 0.05 MCL No 0.16 2 MCL No NO (0.01) 0.005 MCL No 0.0022 0.015 MCL No NO (<0.05) 0.14 MCL No 16.2 3 PSL Potable-No Process-Ye (3) 5 5 MCL No Trichloroethytone ug/L ND (<5) 22 Methyene Chloride ug/L ND(<5) S MCL Potable-No Process-Yes (4) 5 MCL No Freon113 UB/L NO (<10) 270 59000 RBC No Lagend- MCL = Maximum Contaminant Level for drinking water. PSL = Preliminary Screening Level: see Table 6.6 and Section 6.4.2. RBC = Risk-based concentration for tap water (USEPA Region III, 1999} - Not analyzed (1) Well 336 (AM07-PW01) (2) Process Water Wells. K16-PW01 K16-PW01 L17-PW01 L17-PW01 V05-PW01 V05-PW01 L04-PW01 L04-PW01 (3) Trichloroethytene exceeded the MCL in production uwH V05-PW01. (4) FC-143 exceeded the preliminary SL in production wells K16-PW01, V05-PW01. and L04-PW01. S H^>*<d^.">I<TlblBltll^-^^:llt:<AM Pane I t 1 EID090491 TABLE 6.9 RARE, THREATENED, AND ENDANGERED TERRESTRIAL SPECIES (1) Peregrine Falcon (Falcoperegrimis) Bald eagle (Haliaeetus leucocephaivs) Virginia big-eared bat (Corynorhhws tamisendii virginianus) Indiana bat {Myotis sodalis) Gray bat (M. pisescaa) Northern flying squirrel (Glaucomys sabrinusfuscvs) Eastern cougar {Felis concilia) Cheat Mountian salamander (Plethodon netting!) Flat-spired three-toothed land snail (Triodopsis platysayoides) Shale baircn rockcress (Arabis serotina) Running buffalo clover (7>ifoliimi stolanlferum) Harperella (Ptilimnium nadosum) Northeastern bulrush (Scapus ancistracfiaetus) Virginia spiraea (Spiraea vwgimww) (1) Source: West Virginia Division of Natural Resources. These speciesare listed by both the U. S. Fish and Wildlife and the West Virginia Natural Heritage Program. EID090492 TABLE 6.10 RISK EVALUATION RESULTS Do Constituent Levels Pose Potential Concern? Exposure Medium BGSoil PWI Soil RBL/ADPSoil Potable Water Wells (2) Process Water WeUs (3) SWMU Impacted Groundwater SoUO-2ft No No No Soffl2-20ft No No No Groundwater No No Contained on site (1) No = All constituent concentrations were below health screening levels or (for industrial process water) were below levels that would be expected to pose a concern under intermittent exposure during manutuC'.nnng o[H.ratio:u. lliae were no significant ecological resources or lisicd speJes iueiititled within the RFI study area. (2) Potable water well Well 336 (AM07-PW01). (3) Process waterwells = K16-PW01, L17-PW01, V05-PW01, L04-PW01. EID090493