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AR226-2548 RCRA FACILITY INVESTIGATION REPORT DUPONT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA JUNE 30,1999 Project No. 0D6W7205 ASH000246 Prepared by <90B& v C O R P O R A T E REM ED IA TIO N G R O U P An Alliance between DuPont and The W-C Diamond Group Barley Mill Plaza, Building 27 Wilmington, Delaware 19880-0027 EID090342 III I } I t^OOOHSV ! EID090343 WYM//P/////M/A i APPROXIMATE AERIAL EXTENT MANAGEMENT UNIT C -6 OF SOLID V APPROXIMATE AERIAL EXTENT OF SOLID V ; ' MANAGEMENT UNIT H-14 j AERIAL EXTENT OF SOLID V -------: MANAGEMENT UNIT A -3 APPROXIMATE AERIAL EXTENT OF SOLID VI M MANAGEMENT UNIT B -4 PERMITTED HAZARDOUS VASTE FACILITY EID090344 TITLE: A RFI SOIL SAMPLING p DuPONT WASHING^ WASHINGTON, WES'1 V * FEET ASH000248 OWN: DHE CHKO: DES.: APPO: DATE: 0 5 /2 4 /9 9 REV.: 0 FILE NUMBER: 7205D002 FIGURE NO.: 3.1 &v. y&'iV -> * * n iV > ^ ^ |- w' V* < * * . , * , , * '1 \ y t; -v^ T >w - h if -, r- i OVED ASH DRAWING NO / PROJECT NO Tf _*. H- ' V --Vit ^ -1 -.-4 .4.' W r ? - e, , -5 *& '?yi ` , touts & Co. Irr; si WORKS ST VI RGI NI A ASH000249 EID090345 < p n fij> DuPont Washington Works P O. Box 1217 Parkersburg, WV 26102-121? CERTIFIED MAIL RETURN RECEIPT REQUESTED Mr. M artin Kotsch Project Manager U.S. EPA, Region in 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 o f Findings for your review and comment. If you have any questions or comments, please contact me at (304) 863-4271. Very truly yours, Attachment CC: Mr. Marie Priddy Office o f Waste Management WV-DEP 1356 Hansford Street Charleston, WV 25301 Mr. B. F. Smith, Chief* Office o f Waste Management Charleston, WV 25301 1356 Hansford Street * cover letter only R. L. Ritchey Sr. Environmental Control Consultant Washington Works Ms. Barbara Taylor, Chief* Office o f Water Resources WV-DEP 1201 Greenbrier Street Charleston, WV 25311 ASH000250 EID090346 RCRA FACILITY INVESTIGATION REPORT DUPONT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA USEPA PERMIT NUMBER WVD04-587-5291 ASH000251 June 30, 1999 Project No. 0D6W7205 C O R P O R A T E R E M E D IA T IO N G R O U P An A lliance betw een DuPontand The W C Diamond Group Barley Mill Plaza, Building 2 7 Wilmington, Delaw are 19880-0027 (M u /n /u l/ sA c 'Husjp J*- or -ifz--a--o1.e_tjj_n -m s- no. p_ 77 W -C Diamond Project M anager Project Director Deputy Project M anager EID090347 TABLE OF CONTENTS Executive Summary.................. ................................... -....................................................... ......... ES-1 Section 1 introduction................................................................................................................ 1-1 1.1 SWMU Descriptions....................................................................................1-1 1.2 RFI Purpose and Investigation Tasks............................... .-.......................1-2 1.3 Guidance Documents...................................................................................1-2 Section 2 Facility Description............ ....................................... 2-1 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 U se.........................................2-3 2.5 Local Geology and Hydrogeology..............................................................2-3 2.5.1 Groundwater Flow Directions............... 2-4 2.5.2 Transmissivity, Hydraulic Conductivity, and Groundwater Flow Velocity.................................................................................. 2-5 2.6 Surface Water...............................................................................................2-5 2.7 Known Releases From Site SWMUs......................................................... 2-6 Section 3 RCRA Facility Field 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 SWMUA-3--Riverbank Landfill (RBL) and . SWMU B-4-- Anaerobic Digestion Ponds (A D P)....................... 3-5 3.4.2 SWMU C-6--Polyacetal Waste Incinerator (PW I)................;.... 3-6 3.4.3 SWMU H-14-- Burning Ground (B G ).......................................... 3-6 3.5 Background Soil Sampling......................................................................... 3-6 3.6 Soil Geotechnical Analysis..........................................................................3-7 3.7. Slug Testing................................................................................................. 3-7 3.8 Revised Nomenclature................................................................................ 3-8 3.9 Surveying................... 3-8 3.10 Waste Management..................................................................................... 3-8 3.11 Decontamination...........................i................................................................3-9 j* 3.12 Quality Assurance/Quality Control...........................................................3-10 3.13 Sample Preservation.................................................................................. 3-11 3.14 Field Custody Procedures......................................................................... 3-11 CORPORAATiME RmCMnCMOIMmtmONCROUP O vP vttnt TtmwearemriOwp BwtavMaptaa.au!*27 C:\MARY\720S\7205RFI.DOCV3CWUN-99\7205V 1 ASH000252 EID090348 TABU OF CONTENTS Section 4 Section 5 Section 6 R C R A Field Investigation Results 4-1 4.1 Data Quality Review......................................................... 4.1.1 RFI Data Quality Objectives................................ 4.1.2 RFI AnalyticalProtocol Deviations..................... 4.1.3 RFI Data Usability Review and Data Validation. 4.2 Soil Investigation............................................................................. 4.2.1 Background Soil Sampling................................................. 4.2.2 SWMU A-3--Riverbank Landfill (RBL) and SWMU B- 4--Anaerobic Digestion Ponds.................................. 4.2.3 SWMU C-6 -- Polyacetal Waste Incinerator (PWI) 4.2.4 SWMU H -14-- Burning Ground (B G )................... 4.2.5 Soil Investigation Summary....................................... 4.3 Groundwater Investigation..................................................... 4.3.1 Plantwide Groundwater Sampling............................ 4.3.2 Groundwater Investigation Summary....................... 4-1 4-2 4-2 4-3 4-4 4-4 4-5 4-6 4-6 4-6 4-7 4-7 4-8 Washington Works Groundwater Model... ................................................. 5-1 5.1 Introduction............................................. 5.2 Conceptual Hydrogeologie M odel......... 5.3 Groundwater Flow Model Development 5.4 Model Calibration................................... 5.5 Sensitivity Analysis............................. 5.6 Conclusion o f Groundwater Modeling 5.7 Model Limitations.. 5-1 5-1 5-2 5-3 5-4 5-5 5-5 Screening Level Risk Evaluation.. 6-1 6.1 Objectives and Approach......................>................................................. . 6-1 6.2 Site Description and Land U se.................................. ............................ .6-2 6.2.1 On-Site and Adjacent Land U se............................................. -k. .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 Potential Human Receptors.............................................. .6-4 6.4.2 Screening Levels Used In the Evaluation....................... .6-5 6.4.3 Derivation o f Preliminary Screening Levels for FC-143 . 6-6 6.4.4 Results o f Risk-Based Screening for Soil....................... .6-7 6.4.5 Risk Screening for Production Well W ater.................... .6-7 6.5 Summary o f Constituents and Pathways o f Concern (Human H ealth).......................... ................................................................. 6-8 C:\MARY\7205V7205RFI.OOC\29-JUN-99\72OS\ 11 / I ASH000253 EID090349 ASH000254 os06oaia g wVD ; ^ \ r j^p v T fV ] TABU OF CONTENTS 6.6 Ecological Exposure Evaluation.................................................................6-8 6.6.1 Exposure Areas and M edia.............................................................6-8 6.6.2 Habitat Characterization at the RBL/ADP.....................................6-9 6.6.3 Identification o f Significant Ecological Resources.......................6-9 6.6.4 Ecological Exposure Pathway Evaluation................. 6-10 6.7 Summary and Conclusions....................................................................... 6-10 Section 7 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 C o n tro l............................................................................................. 7-2 7.3 Recommendations............................... 7-2 Section 8 References......................................................................................... 8*1 Figure 1.1 Figure 2.1 Figure 2.2 Figure 2.3 Figure 2.4 Figure 2.5 Figure 2.5A Figure 2.5B Figure 2.5C Figure 2.5D Figure 2.5E Figure 2.5F Figure 2.6 Figure 2.7 Figure 2.8 Figure 3.1 Figure 3.2 Figure 4.1 F IG U R E S SWMU Location Map Site Location Map Nearby Industrial Land Use Regional Stratigraphic Column DuPont Production Well Fields Cross Section Location Map Cross Section A-A' Cross Section B-B' Cross Section C-C' Cross Section D-D' Cross Section E-E' Cross Section F-F' Schematic Diagram o f Riverbank Slumping o f Floodplain Deposits Groundwater Round 1 Contours Groundwater Round 2 Contours RFI Sample Locations Groundwater Round 1 and 2 Sample Locations Methylene Chloride Results in Soil CORPORATE RB<<ED<ATIONOROUP 0vflMrANafMnUithKCMOmMmM<SWv Iv M y M I P is a . M U lng 27 C:\MARY\72O5\72O5RFIOOCV29-JUN-99V7205\ ASH000255 EID090351 TABU OF CONTENTS 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 FC-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 Potentiometrie Surface with Residuals Calibrated Groundwater Model Scatter Plot o f Target Heads vs. Model Heads Sensitivity Analyses Scatter Plot o f Target Heads vs. Model Heads Model Verification Predicted Groundwater Potentiometrie Surface with Reduced Pumping Human Exposure Pathway Evaluation Ecological Exposure Pathway Evaluation CORPORATE ft Ah /UU O A M M O iH tC O b im tl A WHuUiv f i. M r m IMM402T C:\MARY\7205\7205RFI.DOC\29-JUN-99\7205\ iV ASH000256 E1D090352 TABU OF CONTENTS 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 o f Risk-Based Screening for Soil Summary o f Health-Based Screening for Production Well Water Rare, Threatened and Endangered Species Summary o f Risk Evaluation Results ASH000257 CORPORATE RBAEOMTtONGROUP aA*n ATOtmwWmvCMOwtMmM*rf<lp Brrliy M l t TT ** *" " ' nunam C:\MARY\72Q5V7205RFI.DOQ29-JUN-9917205V V EID090353 TABLE OF CONTENTS A P P E N D IC E S Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Sort-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 . M onitoring Well Construction Diagrams Attachment 1 Land Use Report ATTACHMENTS ASH000258 COfUKMATE RMED4ATWWOAOUP O iA n t M * 77 W-C O m ta n i Onu Sarty M i PItfA SMng 27 . C.AMARY\7205\7205Rf:I.DOC\29-JUN-99\72QS\ V I EID090354 RCRA FACILITY INVESTIGATION REPORT ACRO N YM LIST ADP= ADQM= AEL= ASTM = BG= B G S= CED= CEG= CLP= COC= CRG= CSR= CT= DOT= DQO= DTW = ECD= E SI= FC-143= FID = ft/sec= GC= GE= gpd/ft2= gpm = HQ= HSW A= LLI= MCL= M eCl= m g/kg= M S= Anaerobic Digestion Ponds Analytical D ata Qualify Managem ent Allow able Exposure Level Am erican Society for Testing and Materials Burning Ground Below Ground Surface Corporate Environmental D atabase Com m unity Exposure Guideline Contract Laboratory Program Chain of Custody Corporate Remediation Group C o d e o f State Regulations Carbon Tetrachloride Department o f Transportation D ata Qualify Objectives Depth to W ater Electronic Capture Detector Environmental Standards, Inc. Am m onium Perfluorooctanoate Flam e Ionization Detector Feet Per Second G a s Chromatograph General Electric Plastics G allons Per D ay Per Square Foot G allons Per Minute Hazard Quotient H azardous and Solid W aste Am endm ents Lancaster Laboratories, Inc. Maxim um Contaminant Levels Methylene Chloride Seep M illigram s Per Kilogram Matrix Spike M SD = M SL= ND= PCE= PEF= P ID = PPE= PSD= PVC= PW I= QA= QAPP= QC= RBC= RBL= RBLL1= RCRA= R F I= RTE= SCM = SL= SO P= SW MU= TCE= TCLP= pg/kg= pg/L= USEPA= U SG S= V l= VOC= Matrix Spike Duplicate Mean Se a Level Non-Detect Tetrachloroethene Particulate Em ission Factor Photo Ionization Detector Personal Protective Equipment Public Service District Polyvinyl Chloride Polyacetal W aste Incinerator Qualify Assurance Qualify A ssurance Project Plan Qualify Control R isk-Based Concentrations River-Bank Landfill Methylene Chloride Seep Resource Conservation and Recovery Act R C R A Facility Investigation Rare, Threatened or Endangered Site Conceptual Model Screening Levels Standard Operating Procedure Solid W aste Managem ent Unit Trlchloroethene Toxicity Characteristic Leaching Procedure M icrogram s Per Kilogram M icrogram s P er Liter U.S. Environmental Protection Agency United States Geological Survey Verification Investigation Volatile O rganic Com pound ASH000259 EID090355 Executive Surnm an A Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) was conducted in the fall o f 1998 on four Solid Waste Management Units (SWMUs) at the DuPont Washington Works to satisfy requirements o f its RCRA Hazardous and Solid Waste Amendments (HSWA) Permit Number WVB 04-587-2591. The primary objectives o f this investigation were to determine the nature and extent o f waste constituent releases from these units into 'underlying soil, determine the rate o f 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 o f the 1992 Verification Investigation (VI), which determined that each o f these units had potentially released waste constituents into underlying soil and groundwater. The RFI scope o f 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. TTie RFI effort also included construction o f a site-wide groundwater flow model to evaluate the impact o f 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 o f SWMU-impacted groundwater. Soil and groundwater analytical results were compared to USEPA Region in 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 o f the RFI are summarized as follows: 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 HI industrial soil RBCs. 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. 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 prim arily used for non-contact industrial purposes. Ongoing production well pumping, as confirmed by the groundwater flow model, prevents off-site migration o f SWMU-derived waste constituents. Although not planned, COWOGATB RUeOUTtON 0 * 0 u * OPMaw ntw cOMOMi VWmngiM.M I M S W T C:\MARY\7205\7205RFI.DOCN29-JUN-99\7205\ ES"1 ASH000260 EID090356 Executive Summary this pumping could be reduced by as much as 65% while still maintaining site groundwater capture. 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 prim arily utilized for non-contact industrial purposes. 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 M igration Under Control. DuPont recommends the following current and future activities at Washington Works pursuant to its HSWA Permit/Corrective Action Program: Continue operation o f the methylene chloride seep (RBLL1) collection/treatment system. M aintain production well pumping at or above 35% o f present levels. Conduct long-term site aquifer potentiometric surface monitoring to continue to verify site groundwater capture. Conduct long-term groundwater quality monitoring to continue to ensure protection o f human health and the environment. ASH000261 CORPORAATiAEORmEMmBMKAmTmIOhNOR' OUP O P e n f M Jim W 4! O f m r t O m * 1MMCOgPlau. Z7 C:\MARY\7205\7205RFI.DOC\29-JUN-99\72fl5\ ES-2 EID090357 SECTIONONE Introduction In response to the United States Environmental Protection Agency (USEPA) letter o f May 5, 1997, and in accordance with the Corrective Action portion o f 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): SWMUA-3-- Riverbank Landfill (RBL) SWMU B-4-- Anaerobic Digestion Ponds (ADP) SWMU C-6--Polyacetal Waste Incinerator (PW1) O SWMU H-14--Burning Ground (BG) 1.1 SWMU DESCRIPTIONS A brief description o f each o f the SWMUs is presented below. SWMU locations are shown on Figure 1.1. SWMU A-3, Riverbank Landfill (RBL): The RBL is about 4,500 feet long and lies along the northern edge o f 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 o f soil. Currently, the RBL is covered w ith dense vegetation (on its slope) or by buildings and pavement in the manufacturing area. SWMU B-4, Anaerobic Digestion Ponds (ADPs): Three former ADPs are co-located with a portion o f 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 o f clay liner and pond berm material were removed and disposed o f off site. The pond area was backfilled and capped with topsoil, and the area is currently vegetated with grass. SWMU C-6, Polyacetal Waste Incinerator (PWI): The former PWI consisted o f two brick-lined pits in the western portion o f the manufacturing area. The PWI operated between 1959 and 1990. The PWI has been excavated and backfilled with clean soil. SWMU H-14, Burning Ground (BG): The BG is located in the central portion o f 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 o f releases o f organic constituents and possibly metals to soil and groundwater at the RBL, ADP, and BG (DuPont 1992). Little evidence o f contamination was found in soil at the site o f die former PWI. Further investigations and evaluations were performed for this RFI, and are reported herein. _ CORPORA! RtMCOMION O ftou* OvP--t mA*tATfKc*m**cCiMOWwaMontfO m * ty MB P la n . Butting 37 C:\MARY\7205\7205RFIDOC\29-JUN-99V7205\ 1 - 1 ASH000262 EID090358 S E C T IO N O N E Introduction 1.2 RFI PURPOSE AND INVESTIGATION TASKS This RFI Report was prepared in accordance with the RCRA Facility Investigation Plan that was submitted to USEPAin 1997 (DuPont 1997). The purpose o f the RFI Report is to: Summarize the nature and extent o f releases o f SWMU-related constituents and, if applicable, rate o f migration. Provide a detailed geologic and hydrogeologic characterization o f the area surrounding and underlying the SWMUs. Identify if potential releases are a concern for human health or the environment. Determine if further actions are warranted for the SWMUs. The RFI tasks that were performed to meet these objectives include: Background soil sampling. SWMU-specific soil and groundwater sampling. Site-wide monitoring well installation and groundwater sampling, and closure o f old monitoring wells determined by site-wide survey. Data evaluation and identification o f sources o f release and nature and extent o f contamination. Hydrogeologic characterization and groundwater flow model development and calibration. Identification o f 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 o f this RFI. RCRA Groundwater Monitoring: Draft Technical Guidance (USEPA Office o f Solid Waste, November 1992); Test Methodsfo r 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 o f Concern by Risk-Based Screening (USEPA Region III, 1993), and other guidance documents as cited in the report. COAPO* SM i WfeWflgUn, M a t IMMQMT 1-2C:\MARY\7205\7205RFI.DOC\29-JUN-99\7205\ ASH000263 EID090359 SECTI0NTWO Facility Description 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 o f Parkersburg, 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 m ile along the Ohio River. Products manufactured at the site include: Compounded engineering plastics Nylon molding pellets and filaments a Acrylic molding compounds Polyvinyl butyral Acrylic resins Fluoropolymers Polyacetal products ' Washington Works is located in an area o f industrial and other land uses. Immediately adjacent to the western boundary o f the plant site is the General Electric Plastics plant (GE) and two industrial warehouses (see Figure 2.2). The north side o f 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 o f the site. The east side o f 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 o f several Washington Works groundwater well fields is located on the island. ASH000264 CORPORATE REMSBATON GROUP A iA V M NM NM OuPmtuH nY*-C avm t*artM 0 Birfar M i Pfe n . M M * JT MMKnmn.Ottwi-- MMO 0077 C:\MARY\7205\7205RFI.DOC\29-JUN-99\7205\ 2- 1 EID090360 SiCTIONTWO Facility Description 2.1 TOPOGRAPHIC SETTING The W ashington Works plant rests on Quaternary alluvial terrace deposits in western West Virginia's Q hiaR iver 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 o f the Dunkard Series that rises steeply and outcrops off the southern edge o f the site to form the valley wall. The valley wall rises from an elevation o f630 feet above mean sea level (MSL) near the southern edge o f the site to 860 feet above MSL at the Local Landfill (see Figure 2.2). This highftr knob country south o f the site is characterized by branching V-shaped valleys typical o f a dissected plateau geomorphology. 2.2 REGIONAL GEOLOGIC SETTING The W ashington W orks plant lies on the western edge o f 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 o f unconsolidated river deposits o f poorly to well-sorted, brown and gray sand, silts, clay and gravel. The Dunkard Series bedrock consists primarily o f red and varicolored sandy shale; gray, green and brown sandstone; and minor beds o f 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. W ells 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: infiltration o f precipitation falling directly on the alluvium Lateral movement o f the river water through the alluvium via permeable sands andjravel zones ' Seepage from streams tributary to the Ohio River The maximum amount o f water available to the alluvium depends on the degree o f hydraulic connection to the river. The degree o f hydraulic connection is a function o f the condition o f the river bottom, permeability and thickness o f the alluvium, and distance and hydraulic gradient between the wells and river. Pumping o f on-site active well fields near and parallel to the river (i.e., the Ranney W ell, 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. CORPORATE REMEOUnO* OROUP OiPWaflrf!*WfcCOM*wdOwp l a t M lPlus. But* 3 t Wfri*an. M w a IMSCOOg 2-2C:\MARYV72Q5\7205RFI.DOC\29-JUN-99\7205\ ASH000265 EID090361 S1CTIQMTWO Facility Description 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 o f the Dunkard Series that rises steeply and outcrops o ff the southern edge o f die site to form the valley wall. The valley wall rises from an elevation o f 630 feet above mean sea level (MSL) near the southern edge o f the site to 860 feet above MSL at the Local Landfill (see Figure 2.2). This higher knob country south o f the site is characterized by branching V-shaped valleys typical o f a dissected plateau geomorphology. 2.2 REGIONAL GEOLOGIC SETTING The W ashington Works plant lies on the western edge o f the Appalachian Gosynclinal 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 o f unconsolidated river deposits o f poorly to well-sorted, brown and gray sand, silts, clay and gravel. The Dunkard Series bedrock consists primarily o f red and varicolored sandy shale; gray, green and brown sandstone; and minor beds o f 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 reportai (Schultz 1984). Natural recharge to the alluvial aquifer comes from various sources, including: infiltration o f precipitation falling directly on the alluyium Lateral movement o f the river water through the alluvium via permeable sands and gravel zones "- Seepage from streams tributary to the Ohio River The maximum amount o f water available to the alluvium depends on the degree o f hydraulic connection to the river. The degree o f hydraulic connection is a function o f the condition o f the river bottom, permeability and thickness o f the alluvium, and distance and hydraulic gradient between the wells and river. Pumping o f on-site active well fields near and parallel to the river (i.e., the Ranney W ell, 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. CORPORATE REMEHATIQM9N0UP and TU*MKCOtanonrfO m fl eh*Mmu.eui*2r OafaM IW M 0 P 2-2C :\M A R Y \7205\7205RFI.D O C \30-JU N -99\7205\ ASH000266 EID090362 SiCiWNTWO Facility Description 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 o f 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 w ell's position with respect to the river, as well as formation grain size and thickness. The groundwater quality in the alluvium in this region tends to be naturally poor, having the highest median chloride, sulfate, hardness (as calcium carbonate), iron, and manganese concentrations o f 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 die 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 o f Parkersburg, 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 o f Ohio River terrace deposits o f 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 o f silt, clay, and fine grained sand to approximately 20 to 30 feet, followed by approximately 20 to 30 feet o f coarse sand and gravel, which extends down to the top o f the bedrock (part o f the Permian-age Dunkard Group). To the south on the main plant area and above the riverbank, approximately 10 to ' 20 feet o f silt, clay, and fine-grained sand overlie approximately 80 to 100 feet o f sand and gravel to approximately 90 to 120 feet deep (the top o f 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 o f 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. -- 2-3C :\M A R Y \7205\7205R FI.D O C \29-JU N -99\7205\ A SH 000267 EID090363 SiiTIOMTWO l^iGilitir Descripflon The bedrock unit that underlies the Ohio River terrace deposits consists o f interbedded sandstones, siltstones, claystones, shales, occasional limestones, and coal zones. This formation belongs to the Perxnian-age Dunkard Group. Soil borings drilled in the early 1970s at the northwest com er o f the site indicate that the top o f the bedrock zone, which immediately underlies the upper alluvial sand and gravel o f the Ohio River terrace deposits, is shale at approximately 530 feet above MSL. To the south o f the plant toward the edge o f the Ohio River depositional valley, the Ohio River terrace deposits thin out. Bedrock o f the Dunkard Group is present at the ground surface south o f the site at the Local Landfill. Due to riverbank undercutting, some slumping o f clay and silt exists along the northern boundary o f the property along the river's edge. An interpretation o f the typical Ohio Riverbank stratigraphy is presented in Figure 2.6 (Caristn 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 , o f the underlying shallow clay and discharges along the riverbank. Figure 2.5C shows an example o f the relationship o f 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 o f 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 o f 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 m ajor aquifer. In fact, the upper zone o f the Dunkard Group, primarily a shale and silt matrix, bounds the lower portion o f the site aquifer and serves as a confining unit to underlying geologic units. 2.5.1 Groundw ater 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 o f on-site production wells. The Ohio River is the primary source o f 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 o f2,000 gpm; and the five DuPont-Lubeck wells, which pump about 70ft 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 o f 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 o f the site is toward the East Well Field wells from the south and from the north. In the north-central portion o f the site, groundwater flow is toward the Ranney Well. In the central and western portion o f the site, groundwater flow is south-southwest towards the DuPont-Lubeck Well Field. Pumping o f the production wells (Ranney Well, East Well Field, and the DuPont-Lubeck Well Field) eliminates off-site migration o f groundwater which may emanate from the SWMU areas. CORPORATEMEDIATION OHOUR n w ca M fl v a to 'M ffO A .a u U n tZ r VHrtrQUn.amra WOta g 2-4C :\M A R Y \7205\7205R FI.O O C \29-JU N -S9tf205\ ASH000268 EID090364 ! ^ ') ( " ' ^i SECTIONTWO Facility Description 2.5.2 Transmissivity, Hydraulic Conductivity, and Groundwater Flow Velocity In a 1990 hydrogeologic assessment, production well specific capacity testing o f the DuPontLubeck W ell Field-and the East Well Field was conducted. The results were used to calculate the transmissivity o f the site aquifer (DuPont 1990). The results indicated that the transmissivity values for the site aquifer in the vicinity o f the DuPont-Lubeck W ell Field appear to be higher than the values calculated in the vicinity o f the East Well Field, h i the vicinity o f 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 o f the East Well Field, die values ranged between 16,050 and 50,000 gpd/ft2. The differences in the shape, depth, and extent o f the cones o f depression between these two areas support the transm issivity 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 o f 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 o f the site. A groundwater flow velocity o f 3 ft/d was estimated between monitoring wells TW-33 and TW-M4 in the western central portion o f the site. In the eastern portion o f the site, a groundwater flow velocity o f 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 o f 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 o f the plant site is covered with asphalt and concrete. Therefore, much o f the precipitation falling on site is routed toward drains and storm sewers, which ultimately discharge into the Ohio River. Precipitation frilling 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 o f the Ohio River deposits that underlie topsoil and fill along the riverbank. Precipitation falling on the unpaved southern portion o f the site most likely migrates downward toward the unconfined water table, but may be limited by the shallow layers o f clay and silt o f the Ohio River terrace deposits. 4Q0 ^ CORPORATE REMEDIATIONOROUP ArtAHm m tMfMMn aPptfw nw W tC O few enFO ra* WrM dF'U U .B iM n g Z r ww C:\MARY\7205\7205RF1.DOC\29-JUN-99\7205\ Z - J E1D090365 ASH000269 SICnOHTWO taluni DescrhniM Two drainage swales, one located in the facility's southwest comer, and the other located on the extreme eastern end o f the facility, also convey surface runoff during rainy weather to the Ohio River. During dry weather, 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 o f releases of organic constituents and possibly metals to soil and groundwater at the RBL, ADP, and BG. Little evidence o f release was found in soil at the site o f the former PWI. At the RBL/ADP area (in the western portion o f the RBL), several organic constituents and rnptaig 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. FC-143 and Triton-X were also detected in groundwater and seep samples in this area. Soil samples that were collected in the vicinity o f the RBL/ADP during the VI did not have significant levels o f site-related constituents, indicating that releases to groundwater and to surface seeps are the chief migration pathways from these SWMUs. The source o f 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 o f organic constituents to groundwater was identified in the 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 o f these metals in groundwater is probably not due to leaching from soils at the BG. Soil samples did not have significant levels o f 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 o f the RFI was to determine if the BG was the source o f 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 o f significant releases to adjacent soil at the site o f 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. CORPORATO MM0MT1OMMOUP 2*6C:\MARY\7205\7205RFI.DOO29-JUN-99\72a5\ ASH000270 EID090366 SICTWMTHREE RCRA Facility Field Investioation 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 o f site geologic and hydrogeologic conditions so that constituent transport can be predicted. The RFI was also 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: Site-wide monitoring well installation Site-wide groundwater sampling (2 rounds) Background soil sampling 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 o f 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 o f 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 o f 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 o f screening spatial and vertical differences o f volatile organic vapors at the various sampling locations. Monitoring was conducted to fulfill requirements o f the Health and Safety Plan included in the RFI Work Plan ' and to assist in sample screening. ' CORPORATE ttlC O K tW M OR M ABM CtlM UM DkPmr m r MtcoriflMfttfa 3*1C:\MARY\72Q5V72O5RFI.DOCV29-JUN-99\7205\ ASH000271 EID090367 SICTEQNTHREE RCRAFa Field investigation In general, samples were collected in the following order to reduce the loss o f volatile components: Volatile organic compounds (VOCs) Q Extractable organics M etals 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 18-to-24-inch interval (BGS) was collected for VOC analysis because volatile organics in the deeper portion o f 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 FID. 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 o f VOCs from the sample prior to analysis. After the 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 the soil sample was decontaminated prior to each use according to the general decontamination procedures discussed in Section 3.11 o f this report. During sample collection, a geologist recorded soil descriptions on the basis o f visual observations in accordance with the Unified Soil Classification System (equivalent to ASTM D2487 69). Boring logs that provide a description o f the penetrated soil profile were completed for each sample (see Appendix E). All PID/FED readings were noted on the boring logs. Upon completion o f 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. 3.2 SITE-WIDE MONITORING WELL INSTALLATIONS The RFI field investigation included installation o f 24 site-wide monitoring wells to supplement the existing monitoring wells within or near the specific SWMUs being investigated. Monitoring well locations ar 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 HI in August 1998. (RFI Work Plan: CORPORATE REMCOWDOMOIIOUP DM flw OAMWtffe w * 0%ftumau, z t HMMBT 3-2C :\M A R Y \7205\7205R Fi.D O C \29-JU N -99\7205\ ASH000272 EID090368 SECTIONTHREE sens Facility Field Investigation Groundwater M odel Update Report). There were no changes to the proposed sampling locations based on the preliminary model results. All new wells were-iastalled 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 M onitoring W eil Construction M onitoring wells were constructed according to West Virginia Monitoring Well Design Standards 47 CSR 60. No more than 20 feet o f 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 o f the screen. Gravel pack placement was confirmed by line measurements made through the annulus o f 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 o f the borehole. Once in place, the bentonite seal was hydrated with water from the Blennerhassett Island pumping wells. The remainder o f the well annulus to ground surface was tremmie grouted with a cement/bentonite grout that was mixed according to one o f the following specifications: Cement-bentonite 8 gallons o f water to 5 pounds o f bentonite dry mixed per 94-pound bag o f cement . Cem ent-bentonite_iO gallons o f water per 8 pounds o f bentonite water mixed with a 94-pound bag o f 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. W ells that were installed in heavily trafficked areas or roadways were completed with * a Morrison-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 o f qualified geologists and engineers. All newly W M n0an.<M n h IBMP 0027 3-3C :\M A R Y \7205\7205RFI.D O C \30-JU N -99\7205\ ASH000273 EID090369 SICTIDNTHREE RCRA Faculty H eld Investigation installed monitoring wells were registered by the driller within the state o f W est Virginia as per 47 CSR 60. A ll new wells have also been labeled by permanently affixing the W est Virginia registration number to the protective casing or flushmount. Well construction information is summarized in Table 3.3. 3.2.2 M onitoring W ell Development The new wells were allowed to cure a minimum o f 12 hours before being developed. Each new well was thoroughly developed by pumping and/or bailing to remove fines from the screened interval. Total w ell depths necessary to calculate the required purge volumes were tabulated after completion o f the well installation and accompanied the sampling team in the field. All wells were developed for a minimum o f one hour until at least ten well volumes had been purged and turbidity levels visibly decreased. All development water was contained and disposed o f as described in Section 3.10 o f this report. Well development information is summarized in Table 3.4. 3.3 SITE-WIDE GROUNDWATER SAMPLING A total o f 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 o f 1998 (see Figure 3.2). The second groundwater sampling event was conducted during the first and second weeks in February o f 1999. Well Q05-MW01 was not sampled during Round 2 because o f 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. To minimize the potential for cross-contamination, monitoring wells were evacuated and - sampled beginning from the well with the highest potential for contamination to the lowest. The sampling order o f 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 o f three volumes o f water standing in the well casing by using a low-flow submersible pump. A few o f the wells were purged and sampled with a disposable polyethylene bailer because the water column was not large enough to allow the use o f a submersible pump. The depth o f 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 o f pH, specific conductance, turbidity, dissolved oxygen, temperature, and salinity were collected by use o f a Horiba U-10 instrument during well purging. Purging was CORPORATE R M O A T iO N OAOUP 3-4C:\MARY\7205\7205RFI.QOQ23-JUN-S9\7205\ A SH 000274 EID090370 SECTIONTHREE RCRA Facility H eld Investigation completed when at least three well volumes had been evacuated and three consecutive readings o f pH and specific conductance had stabilized to within 10 %. When purging was complete, the well was allowed to recharge 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 cross contamination w ithin and between monitoring wells, as described in Section 3.11. M onitoring instruments and the submersible pump were cleaned with an Alconox detergent wash followed by a deionized w ater rinse. All purge and decontamination water was containerized and disposed o f as described in Section 3.10 o f this report. 3.4 SWMU-SPECIFIC SAMPLING After review o f 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 o f extent o f migration o f SWMU-specific constituents. 3.4.1 SW M U A -3-- Riverbank Landfill (R BL) and SW M U 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, hi general, the sample locations were established to determine the vertical and lateral extent o f 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 o f a series o f 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 o f methylene 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 o f 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 o f constituent migration. Along the length o f the north side o f 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 o f 22 soil sample sites.* 8886 CORPOAATI MEDIATION OAOUP D M W h W C ttZ rfO m * to, U tPteU . 044*927 ***** __ C:\M ARY\720S\r205RFl.D0023-JUN-99\720S\ J - J A SH 000275 EID090371 SECTIONTHREE amRCBfl Facility im w stigailon The south side o f 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 o f the RBL in an effort to supplement the existing well system. The wells were drilled ju st o ff the southern boundary o f the RBL, since the SWMU area itself is inaccessible due to the presence o f 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 o f constituents from the RBL and ADP. As with all o f 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 in comments (EPA 1997) on the VI data from this SWMU, the field investigation at the PWI consisted o f 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 o f 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 o f 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 o f numerous buildings in this area which prevented evenly spaced sampling points. Soil borings included sample collection with depth to delineate vertical distribution o f potential constituents o f 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 pathway. A separate monitoring well completed north o f the BG and south ofthe 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 o f 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 o f spatial variations in background metals concentrations, which may result from szxas. C:\MARY\7205\7205RFI.DOC\29-JUN-99\7205X 3-6 ASH000276 EID090372 S IG T IO N T H R E E BORA Faelinv Field investigation natural geologic processes. The background soil samples were analyzed for the following analytes: arsenic, barium, cadmium, chromium, lead, nickel, methylene chloride, tetrachloroethene, trinhloroethene, andFC-143. 3.6 SOIL GEOTECHNICAL 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: Grain size (sieve analysis) M oisture content Atterberg limits Porosity Vertical permeability 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 o f groundwater sampling in November 1998 after all w ells had been properly developed. In-situ permeability o f the screened interval for each well was evaluated by the instantaneous removal and insertion o f a well slug with a known volume. The response o f 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 unconfined aquifers. Results o f the slug tests were used in calibrating the groundwater model described in Section S. ASH000277 CORPORATO RSMBOttTKM OSCUP A iW m M w i O f m i aitf TO*W C OtomnrfC m * IMma ivun.Dalamra W tM v O Xt 3-7C:\MAfm 7205\7205RFI.DOC\30-JUN-99\7205\ EID090373 S lfiT IO N T H R E E R O IA Facility 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 o f the existing soil boring and monitoring well locations while maintaining an easily usable and understandable system o f 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 o f 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 A P I3 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 wore surveyed once the soil sampling and well installation program was completed. All well locations were surveyed and four measurements were recorded. The elevation o f the ground surface and the top o f 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) o f the wells were surveyed to the nearest 0.01 foot. Each o f the new wells were marked on the top o f 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 ^gch point. Horizontal locations and ground surface elevations were recorded to assist in proper data analysis and cross-section representation. 3.10 WASTE MANAGEMENT v. Waste management procedures are described in the Waste Management Plan (see Appendix F o f the RFI workplan). Each waste stream produced during the RFI was handled in the appropriate maimer as discussed in the following text. The typical wastes that were generated and managed during RFI activities included: Soil cuttings from drilling and augering activities Water from purging and development o f monitoring wells Water from decontaminating sampling and drilling equipment COMORATI REMCOATiON OHOUP tMNrfu * !7wWCOfen*Oive VMM'iw i.CMm 19H04027 C:\MARY\7205\7205RFI.DOC\29-JUN-99\7205\ 3-8 ASH000278 EID090374 SECTIONTHREE BORA Facility H eld Investigation Disposable sampling equipment Disposable personal protective equipment (PPE) 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 o f the soil contained in each individual drum. Additional samples were collected and analyzed following the RFI program to further assess the status o f individual drums. All drums were classified as non-hazardous and w ill be properly disposed o f o ff 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 o f waste water was produced during the sampling activities. A Toxicity Characteristic Leaching Procedure (TCLP) sample o f the waste water was collected and analyzed following the RFI activities and results were compared to TCLP criteria for waste disposal classification. The waste w ater 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 o f 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 w ithin 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 o f the plant using a pressurized steam cleaner and Blennerhassett Island water. Sampling equipment included drilling rigs with augers, hand augers, split-spoon samplers, trowels, spoons, mixing bowls, spatulas, bailers, tubing, and pumps. All o f these items came into direct contact w ith the sample and had a potential to impact analytical results. Therefore, care was taken to ensure the cleanliness o f 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 Blennerhassett 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 COW OfiATl fUEMKOATIOMOnOUP iln iU kiw M M M tevU iPU t*.ufcfrq27 W *ttt<gta,(M OT tMMOMF C:\MARY\7205\7205RFI.D0029-JUN-B9\7205\ 3'9 ASH000279 EID090375 SECTIONTHREE BCBA Facintv H eld invBsugatlon contamination o f the borehole and/or well. All excess soil cuttings and decontamination water were contained and w ill be disposed o f 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 o f 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 o f sampling. Procedures for the decontamination o f protective equipment and the removal o f respiratory and personal protection clothing to avoid transfer o f constituents from clothing to the body are discussed in the Health and Safety Plan (see Appendix E o f the RFI workplan). 3.12 QUALITY ASSURANCE/QUAUTY 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 o f 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 the field. Trip blanks were shipped and analyzed for each shuttle o f 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 w ater 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 o f one in twenty for each appropriate type o f matrix and parameter. Duplicate samples were collected to evaluate the aggregate sampling and analytical precision. ' MS/MSD samples were also collected at a level o f one in twenty. MS/MSD samples were collected to provide a method o f accuracy in a given matrix. The MS was performed by adding a predetermined quantity o f stock solutions o f certain analytes that are representative o f test constituents to a sample matrix prior to the sample extraction/digestion and analysis. The concentration o f the spike was at the regulatory standard level or above the method detection limit. The MSD was collected as a duplicate to the MS to further demonstrate analytical accuracy. CORPORATE RCMSOMTIOM0AOUP .HMbgZt a 1MS&0QZ7 C:\MARY\7205V7205RFI.0OC\29-JUN-89\7205\ 3-10 ASH000280 EID090376 S E G T I0N T H R E E BORA faculty H eld Investigation Equipment blanks (also called rinsate blanks) were used to evaluate equipment cleaning and decontamination 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 o f days. The temperature o f 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 tim e o f sample collection, the following field activities were performed and documented by the investigator: All procedures regarding preparation o f reagents or supplies that were used in sample collection and/or sample preservation. Sample quantity, type (i.e., composite or grab), location, and depth was documented in the investigator's field log. ~ Sample labels were prepared, and they included sample identification numbers, time and date o f collection, proposed laboratory analyses, and name o f sampler. Samples collected in the field by a team o f investigators were the responsibility o f each sampler until the samples were transferred to a person designated as the field sample custodian. Chains o f 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 o f samples, number o f ` 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. - CORPORATEftaC H A tO H O ftO U P C:\M ARY17205\7205RFI.DOC\2W UN.99\7205\ 3 - 1 1 ASH000281 EID090377 S E 6T I0N T H R E E BCRA Facility Held Investigation Prior to sample shuttle delivery to the courier, the sample shipping containers (e.g., cooler, box) were sealed w ith 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 o f the field sample custodian. Z8z o o h sv GOWOftATVMMEOATKM OROUP A iJIm M iN M WMV^IMMaMMOTart* U M taa. M * 3T C:\MARY\7205\72a5RFI.OOC\29-JUN-99\7205\ 3-12 EID090378 S iG T IO N F O U R BORA Held Investigation R esults The following section presents the RCRA Facility Investigation results. It is organized as follows: ' Data Q ualttyReview Soil Investigation Groundwater Investigation In general, the results are presented and discussed on a SWMU by SWMU basis. To provide a qualitative guide to the level o f observed impacts and to help assess their potential significance, all soil analytical results were compared to USEPA Region III 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 o f FC-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 o f 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: Sample receipt Sample log in Sample storage 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. ASH000283 CORPORATE ftEMEOtAtKM OftOUR OoPwU Mtf Ttm MACOTMM* Oftafi MS R IM , VuMrg *7 VMfltfngtan, M tw v UMOOWT C:\MARY\7205V7205RFI.DOC\29-JUN-99\720S\ 4-1 EID090379 S iC T IO N F O U R BOBA Held HivestigaUon Besults 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 Table 1 o f 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 o f all analytical data generated. Results for individual metals were qualified as unusable (flagged R) for project purposes in one or more samples. The loss o f these individual results as a result o f data validation and evaluation did not materially affect the evaluation o f the Washington Works site and did not change the conclusions reached in this report. Eleven sample results were found to be unusable out o f 3,732 total results generated, for a completeness o f 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 frill data validation. 4.1.2 RFI Analytical Protocol Deviations All analytical procedures used by the laboratory for this investigation were USEPA-approved procedures w ith the exception o f the surfactant ammonium perfluorooctoanate (FC-143), for which an USEPA-approved method was not identified. The analytical procedures used for the majority o f the analyses were according to Test Methods for Evaluating Solid Waste Physical/Chemical Methods (SW-846, December 1996). The remaining analyses w ith the exception o f FC-143 were conducted according to Methods for Chemical Analysis o f W ater and Wastes (USEPA 600/4-79-020, March 1988). The FC-143 analysis was performed 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. 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 o f second round groundwater samples. A comparison o f 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 o f groundwater samples were collected from selected wells to verify this discrepancy (see Appendix D). __ .* -- CORPORATERSM80IATKMGROUP A tA IbnM M m w O P * r f I t o W C OfemcMfC m p m rk w rM a N w g ]r C:\MARY\7205\7205RFI.DOC\2S-JUN-99\7205\ 4-2 ASH000284 EID090380 SIC TIO M FO U R RCBA H eld Investigation Results 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 o f 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 fell outside the recommended weight range o f 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 RFI Data Usability Review and Data Validation All o f 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 o f the data. Any major or minor QA/QC deficiencies are noted in the narrative portion o f the laboratory data packages. In addition, full data validation was conducted on 10% o f 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 HI. 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 o f sampling conducted and param eter analyzed during the RFI. Laboratory generated Contract Laboratory Program (CLP)like data packages were selected for validation at random in order to Evaluate approximately 10% of the total number o f samples analyzed Preferentially select samples allowing validation o f a more complete analytical list M inimize the number o f data packages submitted for validation ---- Allow complete data packages to be evaluated As stated in Section 4.1.1, validation o f the sample results by ESI resulted in assessment o f individual target compounds/analytes in one or more samples as unusable for project purposes. Results wore 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 o f the data. CQRPOMTS RflMBSMtION OAOIF OAMltflteWCaMMItav IvtayMirtata.aiAfega Ifrlm kvM lO riaM r* IlM OBQg C:\MARY\72Q5V205RFI.OOC\29>JUN-99\7205\ 4-3 S8Z000Hs EID090381 S iC T IO N F O U R RCHA Field Investigatlon 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) o f sample contamination. .. Qualifiers provided by the data validators as well as those as well as those assigned upon further evaluation o f analytical data were entered into DuPont's Corporate Environmental Database (CED) and are reflected in the tables and figures o f 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 o f 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 o f 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 o f individual SWMU area soil sample results with background concentrations, the following key results are noted: The majority o f individual metal results were less than or equivalent to the respective background concentration. FC-143 was present in several background, near-surface samples. This is attributed to deposition o f airborne particulate originating from the Teflon process area. ASH000286 CORPORATE AMERAftONtMOUP 0^a4Mtf7MtoMmACM0fanraW(fcwe far M l d m Swtmunogo27wr CAMARY\7205tf205RFl.DOC\29-JUN-99W205\ 4-4 EID090382 SieilQNFOUR RGBA nein Investigation Besults (ADP) SWMU A`3-- Riverbank Landfl11<RBL) and SWMU B4-- Anaerobic Digestion Ponds Results for the ADP aud 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 o f the RBLLI seep area to determine the horizontal and vertical extent o f 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 o f MeCl were found m 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 o f MeCl detected was from the 6- to 8-foot interval in M04-SB05 (320,000 pg/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 pg/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 o f the RBL/ADP. Figure 4.2 presents the results o f analysis for Freon-113 in each o f the sample locations. The Freon-113 soil concentrations ranged from nondetect to 9,700 pg/kg. In general, the Freon-113 was detected in subsurface sod samples (i.e., greater than 2 feet). These results confirm similar Freon-113 levels detected during the VI. Low concentrations o f 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 pg/kg and TCE was detected at concentrations up to 8,800 pg/kg. In general, these constituents were detected in subsurface soils (i.e., greater than 2 feet) in a random pattern throughout the limits o f the RBL/ADP. No specific source area was identified. However, the highest concentrations appear to occur near the western portion o f the RBL. FC-143 was detected in a number o f soil samples collected in the RBL/ADP SWMU area. Figures 4.7 through 4.9 present the soil sample locations and results o f the analyses for FC-143 FC-143 was detected at concentrations ranging from 18 to 48,000 pg/kg. The highest results are associated with the ADP area aid occur in soil samples collected from the 8- to 12-foot depth range. These results confirm similar results collected during the VI. Samples collected in the RBL and ADP were also analyzed for five inorganic analytes: arsenic, barium, cadmium, lead and nickel. The detected concentrations o f these inorganic parameters were similar to the mean level found in the background samples (see Section 4.2.1, Background Soil Sampling). .^ CORPORATERSMSXATMMONOUR C:\MARY\7205\72Q5RFI.DOCY29-JUN-99\7205\ 4-5 ASH000287 EID090383 SEGTIONFOUR ROBA Field investigation Results 4.2.3 SWMU C-6-- Polyacetal Waste 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 (xg/kg) within the BG area as indicated on Figure 4.10. FC-143 was also detected in several o f the samples collected in the BG at low concentrations (10 to 140 pg/kg). Figures 4.7 through 4.9 present the results o f 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 o f these inorganic parameters were sim ilar 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 o f 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 o f MeCl impact to soils. In addition, in order to assess qualitatively the level o f observed impacts and their potential significance, all soil sample results were compared to USEPA Region HI RBCs for industrial soil (USEPA Region HI 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: Metal constituents detected in soil were comparable to background concentrations (see Table 4.1). - 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 pg/kg or less). The maximum concentration o f Freon-113 was 9,700 mg/kg at a depth o f 10-12 feet. Extent o f MeCl impacts at die RBLLI seep area appear to be limited to a "hot spot" at about 8 to 10 feet BGS. C:\MARY\7205\7205RFI.OOCV29-JUN-99\7205V 4-6 ASH000288 EID090384 S iG T IO N F O U R RCBA Field Investigation Results The surfactant FC-143 was detected in soil throughout the RBL, ADP, and BG SWMU areas. The highest concentrations (up to 48,000 pg/kg) occurred in ADP area subsurface soils. ___ None o f the organic constituents detected in soil (i.e., PCE, TCE, MeCI, Freon-113, or FC-143) exceeded their respective RBCs (or preliminary screening level for FC-143). Further discussion o f 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 w ith die 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. Methylene Chloride (MeCI) All plant wells were sampled and analyzed for MeCI except for those located within the BG. MeCI was not detected in any o f the groundwater samples collected during either round o f sampling. This includes M04-MW02 and NQ4-MW02, two monitor wells situated between the RBLL1 seep area and the Ohio River. Carbon Tetrachloride (CT) Five wells w ithin and in close proximity to the BG were sampled for CT. CT was detected in samples from two o f the wells. Table 4.2 presents the results'from both rounds o f sampling. Figures 4.11 (Round 1) and 4.12 (Round 2) show the well locations and CT sampling results within the BG SWMU. Detected concentrations ranged from 1 to 16 pg/L. ' Tetrachloroetfaene (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 o f groundwater sampling and demonstrates consistency between rounds. Observed concentrations ranged from 1 to 240 pg/L. mss CORPORATE REM PM TIOHOROUP a m Ai Mnmw cMflmMmria * M k iIr N m h a M M O T C:\MARY\7205\7205RFI.DOC\29-JUN-93\7205\ 4-7 ASH000289 EID090385 SICTIONFOUR RCBA M M Im m U n Bw i Results Trlchloroethene (TCE) Wells that were included in the PCE sampling were also analyzed for TCE. Similar to PCE, TCE was detectediH-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 o f the sample analyses for both groundwater sampling rounds. Observed concentrations ranged from 1 to 800 jig/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 o f the wells sampled. Table 4.5 tabulates the results o f the sample analyses. W ell locations and sample results are presented in Figures 4.17 and 4.18. Observed concentrations ranged from non-detect to 7,100 pg/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 o f the FC-143 sampling for both rounds. Observed concentrations ranged from 0.1 to 13,600 pg/L. Concentrations were below 40 pg/L in 28 o f the 37 wells sampled; in the other 9 wells, maximum concentrations ranged from 380 to 13,600 pg/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 o f the screening criteria for organic compounds occur mainly within the RBL/ADP SWMUs. In light o f these Endings, a thorough analysis o f the site groundwater flow regime and the significant results o f 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 the 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: The seep collection and treatment system is effective at preventing off-site migration o f seeps at RBLL1. The BG is not a significant source o f constituents in the groundwater. The constituents o f concern detected in groundwater are coming from the RBL/ADP SWMUs. CORPOAATKM M O M nO N O N O U ^ M M mmM mm Oi^eiwd rheWCOhmmtfewy W M n#*,OtfM H n M M O r C:\MARY\7205\7205RFI.DOC\29-JUN-99\7205\ 4-8 ASH000290 EID090386 SECTIOHFOUR U U Held InvastlgaUoB Results M etals are naturally occurring and do not. appear to be SWMU-related constituents o f concern. ASH000291 COWORAT1 W K W H O H O B W W n )lw .tM w M ISSH-OOZ? 4-9C:\MARY\7205\7205RFI.DOC\23-JUN-99\7205\ EID090387 SiCTIM FIVE W ashington W orks eronadinator M odel 5.1 INTRODUCTION In accordance w ittrthe September 24,1997, DuPont Washington Works RCRA Facility Investigation Plan, Section 3.1.2, a mathematical model o f groundwater flow at the site was constructed. A preliminary model was constructed in 1998, prior to the initiation o f the RFI sampling activities, to assist in developing a more comprehensive list o f field data needs. The results o f the preliminary modeling were submitted to the USEPA Region III 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 o f 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 o f 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 o f the hydrogeologic model development, all available hydrogeologic data for the Site were reviewed. All site-specific boring logs, groundwater elevation data, water supply well data, and regional hydrogeologic data were compiled and reviewed to determine the number o f 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 o f coarse sand and gravel deposits at the bottom grading up to finer sands, silts, and clays at the top. There are overbank deposits consisting o f 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 o f 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 o f the site, the contact between the alluvial deposits and the consolidated bedrock is relatively flat, at an elevation o f approximately 530 feet above MSL. The bedrock is composed o f Permian-age shale and sandstone o f the Washington Formation which is part o f the Dunkard Group. The bedrock permeability is very low compared to die overlying alluvial river terrace deposits (Schultz 1984). Just south o f State Road 892, the Ohio River terrace ends and the bedrock outcrops at the surface. ASH000292 EID090388 S 1G T I0H F IV E W ashington W orks Groundwater Model m * ? aUuvium at ** site at elevations ranging from approximately 570 to 554 feet MSI* with groundwater flow toward the process water supply wells at the site, llifl water tevel m the 0hio River adjacent to the site averages 582 feet MSL. Groundwater is recharged from ramfall, 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 runoff from bedrock outcrop areas to the south is assumed to be carried away via surface water drainage ditches and therefore does not recharge groundwater. 5.3 GROUNDWATER FLOW MODEL DEVELOPMENT A groundwater flow model o f 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 three dimensional, finite-difference groundwater flow model. The model MODFLOW was used ecause it is well documented and widely accepted by regulatory agencies and industry. The model pre- and postprocessor Model Cad for Windows (Geraghty & M iller) was used to design the model grid, facilitate the building o f 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): ^ o u t h ' North from the middle o f the Ohio River Channel, and south to just below GE. The north to south domain totals 8,800 feet. J East to West - East where the terrace deposits end at the valley wall, and west to the middle o f 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 model;domain (see Figure 5.2). D ie cells were then grouped into zones based on parameters such as hydraulic conductivity and recharge " ,f bedf ck ou^ rP " to o f State Road 892 and northwest o f the Ohio River were set . . . boundaries. No-flow boundary conditions are applied to cells that are outside o f the model s computational domain. A recharge rate o f 11 inches a year was applied over the active flow cells in the model domain wa? 1 ^ to be about 1/3 o f the annual rainfall o f approximately 35 inches a year. Increased recharge along the bedrock outcrop south o f the site was not simulated due to tlu; PnTZ T e !i dramage ditches along State Road 892 that cany away runoff from the bedrock outcrop and prevent it from infiltrating into groundwater. The h io River was modeled as a river with a stage o f584 feet MSL and a bottom o f 553 feet " i eIed aPProximately two feet higher than average because o f greater Jrivprh g m Februuy 1999 which cau?ed a rise in river stage. The model-calibrated rbed conductance was low. The latter is reasonable based on the presence o f the fine-grained a, ^ ' ' ---------------- COnPOfiATE WBMg M n O W OHOUP A P m M U wWCOIm ^ o^ * 5-2C:\M A R Y \7205\7205R FI.D O C \30-JU N -99\7205\ ASH000293 EID090389 SECTIOKFIVE W ashington W orks Groundwater Model sediments which deposit along the low-energy reaches o f the river found along much o f the site boundary and along GE boundary. The bottom o f the one-layer model was assigned an elevation o f 525 feet MSL to approximate the bottom o f the alluvial deposits. Figure 5.3 shows the location o f the boundary conditions, including no-flow cells and river cells. 5.4 MODEL CALIBRATION Once the model was constructed, it was calibrated to data collected from the site on February 1, 1999. This included extraction rate data from 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 o f 1998, pumping rates have been monitored continuously, but in most cases flow meters record flow for a group o f 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 lhe 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% o f 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 o f900 feet per day in the area o f the DuPont-Lubeck Well Field, which coincides w ith a coarsening o f the alluvium in that area (see cross sections in Figures 2.5A-2.5F). The calibrated hydraulic conductivity in the vicinity o f the Ohio River was slightly less, at 200 feet per day. Figure 5.4 shows the location o f the three different conductivity zones. Riverbed conductance is high: in die vicinity o f Blennerhassett Island than in the rest o f the river, but both are estimated by the model to be low, 13.1 feet2 per day (ft 2/d) and 2.3 ft 2/d, respectively. The island is ju st o ff the cut bank or higher energy area o f the Ohio River where coarser sediments are deposited. Riverbed conductance was calibrated at a somewhat lower value, 1.2 ft 2/d, along the downstream portion o f the site and along GE. This low: conductance": coincides w ith the lower energy area o f 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 the 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 % o f 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 o f the wnoNoroup 5-3C:\MARY\7205\72O5RFI.DOC\3O-JUN-SS\7205\ EID090390 SECTIONFIVE W ashington W orks Groundwater Model residuals fall along a line o f perfect fit (i.e., where the modeled head would exactly match the observed head). While scatter is observed along the line o f 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 o f 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 o f 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 sim ilar to the calibrated model and there was very sim ilar 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 o f 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 the sensitivity analysis. Lowering the river stage increased the influence o f the pumping wells. Recharge is unlikely to be as high as 47% o f the annual rainfall (16 inches per year = 47% o f 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 tire 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 o f 582 feet. In both cases all the model heads fell along a line parallel to the line o fperfect fit, but were about 6 feetlow er than observed heads (see Figure 5.8). The discrepancy could be related to input values for river stage, conductivity, conductance, recharge, or pumping rates. O f 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 rainfall 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 o f 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 ,,. 4 ^ eoRpamtsRMDMrioNonoup Oi*W nwttfCMnanrfAw* C:\MARYW20517205WI.OOC\2WUN.97205\ 5~4 ASH000295 EID090391 SECTIBHFIVE m i M M w W arta enundtrauw Model 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 o f maintaining hydraulic control o f 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 o f 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 o f 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 the East W ell 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 o f 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 o f 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 the short-term changes in pumping rates, or seasonal fluctuations in river stage and recharge rates. The boundary conditions to the south o f GE 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 o f 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. _ ASH000296 C:\MARY\7205X7205RRDOC\29-JUN-99\7205\ 5-5 EID090392 SE C T IO N SX Screening level B isk EvaMaflen 6.1 OBJECTIVES AND APPROACH The overall objective-ofthis 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 o f 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 o f potential concern. The ecological evaluation focused on characterizing the habitat within die RFI study area and identifying whether complete exposure pathways exist between SWMU releases and significant ecological resources or receptors. This approach allows identification o f the constituents and exposure routes o f 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: RCRA Facility Investigation Plan, DuPont Washington Works (DuPont, 1997). RCRA Facility Investigation Requirements (included as Attachment D to the RCRA Facility Investigation Plan). USEPA Region IE Technical Guidance Manual "Selecting Exposure Routes and Contaminants o f Concern by Risk-Based Screening" (USEPA Region III, 1993). Q USEPA Region IE Risk-Based Concentration Table (USEPA Region IE, 1999). USEPA guidance for ecological risk assessment (USEPA 1997; 1998a; 1998b). In keeping w ith the above guidance documents, the risk evaluation includes: Description o f on-site and adjacent land use (Section 6.2). Evaluation o f data used in risk screening (Section 6.3). 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). Identification o f constituents and exposure pathways o f concern screening step (Section 6.5). Ecological exposure evaluation (Section 6.6). . Summary and conclusions (Section 6.7). _ <dau> ^ COftfOftATE ftSMEDUnOM GROUP AtJWHHMNM OuflMfMtf111wtc A m? M qpMinHa,INta|lt tMMnflMn.(Manm 11M00WT C:\MARY\7205\7205RFI.DOC\30-JUN-99\7205\ 6-1 EID090393 <t>* O ! ASH000297 SIG T IO N SIX Screening level Risk EvahaUon 6.2 SITE DESCRIPTION AND LAND USE This section provides an overview o f land use at the Washington Works site and identifies potential human aad-ecological receptors. Additional is provided in Attachment 1, Land Use Report information on current and future ... . land use 6.2.1 On-Site and Adjacent Land Use The Washington Works facility has been the site o f 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 m iles west o f Parkersburg, WV. Most o f the facility is developed for manufacturing purposes and is covered with paving, rail tracks, and buildings. Open areas mclude lawns, mowed fields, and a few areas o f natural growth along portions o f the riverbank. he developed portion o f the property is fenced, and access is rigorously controlled by a security system. The riverbank itself lies outside the 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 o f 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 o f Washington, whose eastern extent is adjacent to the DuPont property, and individual homes and subdivisions w ithin about a mile o f the properly 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. t TM e>.adJacent IaTMJ ^ is expected to remain a mix o f 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 f 1 ^ ' mUiUC1f a ' anc*rural water supplies. Depth to groundwater is approximately 6Qto 70 teet in the mam 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 o f this report, DuPont .Wf TM gion Works operates several production well fields on the plant property that provide fA O 0? PWm S S J J f Wa? Ft0 the pIant <PtabIe water is provided by Wells 331 (AO08, PW01), 332 (AQ09-PW01), and 336 (AM07-PW01), in the East Well Field). onT hfrp m "I * 6 direction include eleven industrial and five potable water wells on the GE Plastics site located just to the west o f Washington Works and the Lubeck Pubhc Service D istnct ^ S D ) well field located about 2.3 miles south (downriver) o f the plant. ^ " % f the PPulation * this portion o f Wood j P^D' l9 " u 0ther pnvate welIs or smaI1 community wells o f unknown status were identified during a well search, but they are suspected o f being inactive (see Section 4.3 o f Attachment 1, Location o f Wellhead Protection'Areas and Drinking Water Wells). - <fiBUD ^ CORPORATE REMEDIATION OfKXJP Tht* * U m M M ti WCOtaMtfame JhrtuMijRats.M l '~ ~ . ----- ------------ -------------------C:\MARY\7205\7205RFI.DOC\29-JUN-99\7205\ 6-2 ASH000298 EID090395 SE C T IO N SX Screening le ve l R isk Evaluation As discussed in Section 5, pumping o f the Washington Works well fields controls groundwater flow, so that groundwater affected by SWMU releases is contained on-site. 6.2.3 Surface W ater Surface water o f the Ohio River provides water to the cities o f Parkersburg, W est 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 W ashington 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 runoffto the Ohio River during rainy weather are located on the property, one in the facility's southwest com er and the other on the extreme eastern (upgradient) end o f the property. The former BG and PWI have been excavated, backfilled, and resurfaced, so there are no surface water impacts from these SWMUs. The slopes o f 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 o f production w ell pumping. 6.2.4 E colo gical Setting The W ashington Works site itself is largely developed and used for manufacturing activities, with manicured lawns, mowed fields, and a few areas o f natural growth along portions o f the river bank. These areas provide a narrow and intermittent terrestrial habitat for a variety o f birds, small mammals, and other animals. The upper terraces upstream and downstream from the plant are kept in grassland with some small areas o f 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 o f any federal or state listed species in the vicinity o f the Washington Works Site (West Virginia Division o f Natural Resources [WVDNR], 1999). In addition, no wetlands o f critical terrestrial 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. ASH000299 CCRKMUTE MMCOUnON OHOUP 6-3C:\MARY\7205\72G5RFI.DOCV29-JUN-99\7205\ EID090396 SECT10NS1X Screening level R isk Evaluation 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 die soil data included in the risk evaluation. These Hnta were from samples collected between 0 and 20 feet BGS at the BG and RBL/ADP units. The depth o f 20 feet is considered a conservative estimate o f depth o f 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, VO5-PW01, andLO4-PW 01. W ater 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 o f the exposure medium to which humans are or could be exposed. 6.4 SCREENING-LEVEL HEALTH RISK EVALUATION The purpose o f 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, PW I, ADP) or covered 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. O fthese, 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 o f his/her career. Therefore, evaluating presumed on-site worker exposure to soil at the SWMUs is protective o f construction workers and trespassers, whose exposure would be short-term and interm ittent. 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. " O COftKMATI MMEOUHON OflOUP w<AnAOMn*m M n m BtyM iftau.BM idtrg27 VMngwi,CMaMN IWOWg ~ -------------------------- _A C:\M ARY\7205\7205RFI.00029-JUN-99\7205\ 6 - 4 ASH000300 EID090397 SIG T IO N SIX Screening level R isk Evaluation 6.4.2 Screening Levels Used in the Evaluation Soil data were compared to the following screening levels: USEPA Region HI RBCs for industrial soil (soil ingestion pathway) (USEPA Region HI, 1999). The RBCs are based on a target excess cancer risk o f 10" (1 in 1 million) and a noncancer hazard quotient (HQ) o f 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 o f the property is industrial (Section 6.2.1 and Attachment 1, Land Use Report). A screening level for lead in industrial soil o f 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 1996a). Federal MCLs for drinking water or the federal action level for lead in tap water. USEPA Region m RBCs for tap water (in the absence o f an MCL) (USEPA Region III, 1999). Preliminary screening levels for FC-143 in soil and groundwater (see Section 6.4.3). Certain potential exposure pathways are not included in the derivation o f the screening levels, namely: Inhalation: The inhalation pathway is not included in the derivation o f 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 o f the risk screening for the following reasons. -- First, inhalation o f 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) o f 1.32 x lO4^ m3/kg soil (USEPA 1996b). When applied in the denominator o f an equation to estimate air concentrations o f particulate mutter, 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. __ CORPORATE RB MDIATtONOROUP A tM M ttM W H N VM iPitt*M * ttMMOzr /c C:\MARY\7205\7205RFI.DOCl29s3UN-99\72Q5\ 0 " J ASH000301 EID090398 SEC T IO H SIX Scre e n b g le ve l R isk Evaluation Dermal absorption: The dermal absorption exposure route is not included in the derivation o f 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 o f the screening: a cases where constituent concentrations in soil exceed RBCs, dermal absorption may warrant further consideration in the future. ' M igration to groundwater: Soil screening levels for protection o f 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 HI RBCs for soil and groundwater w o e derived from a health-based Community Exposure Guideline (CEG) o f 0.0003 mg/m3 air (Haskell Laboratory 1991). The CEG was developed by Haskell Laboratory to be protective o f public exposure via the inhalation pathway. The CEG was derived from the DuPont Allowable Exposure Level (AEL) for workers o f 0.01 mg/m . Both the AEL and the CEG are health-protective o f 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 o f 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 o ften to account for the presence o f sensitive subpopulations in the community and again by a safety factor^ofthree to account for a 24-hour/day exposure time, resulting in the CEG o f 0.0003 mg/m . Therefore, the CEG is considered protective o f general public exposures that could include sensitive subpopulations, exposed 24 hours/day. ; Exposure to the CEG o f 0.0003 mg/m3would result in an allowable daily iritap-p o f 0.006 mg/day, assuming an inhalation rate o f 20 m3/day (USEPA Region m 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 o f preliminary screening levels for FC-143 in industrial soil (120 mg/kg) and for groundwater used as drinking water (0.003 rng/L). These preliminary screening levels were used in evaluating site soil and production well water data for FC-143. 4 ^ CORK3K.TC RG M 0 MT10N OROUP C:\MARY\720S\7205RFI.OOC\29-JUN-93\7205\ 6 - 6 ASH000302 EID090399 SC T IO H SIX Screening Level B isk 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 and include the SLs for comparison. Table 6.7 summarizes the results o f the risk- based screening for soil. .. Table 6.7 shows that maximum observed concentrations o f all constituents at all SWMUs and soil intervals were well below their respective screening levels, with the exception o f 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 o f multiple noncarcinogens are also not a concern. Maximum observed concentrations o f all site-related constituents were lower than screening levels by factors o f ten to one million, except for FC-143 and methylene chloride in the 2- to-20-foot interval at the RBL/ADP, where maximum concentrations o f these two constituents were Iowa: than their respective screening levels by a factor o f about 2.4. Because maximum observed concentrations o f 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 MCLs or 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 o f all constituents were below their respective drinking water criteria. To confirm this conclusion, a third round o f 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. In production wells providing industrial process water, maximum concentrations o f all constituents were also below health-based criteria for drinking water, with the exception o f TCEin production well V05-PW01 and FC-143 in production wells K16-PW01, V05-PW01, and L04-PW01. Specifically, the maximum concentration o f TCE (22 micrograms per liter (ug/L)) exceeded the MCL o f 5 ug/L, and the maximum concentration o f FC-143 (16.2 ug/L) exceeded its preliminary screening level for drinking water o f 3 ug/L (Table 6.8). For both constituents, maximum concentrations exceeded their respective drinking water criteria by factors o f 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 o f the drinking water criteria by relatively small factors is not likely to pose health concern for workers,who may be exposed to process water. C C R A X U rg REMEDIATIONO fKXP OAm w TIv IM O Iwwrffea* VAmHen,Odwee 18090087 6-7C:\M ARW 205\7205W I.DOC\29-JUN-99\7205\ ASH000303 EID090400 SEC T IO N SIX Screening level Risk Evaluation 6.5 SUMMARY OF CONSTITUENTS AND PATHWAYS OF CONCERN (HUMAN HEALTH) All constituents iruall media evaluated were below health-protective criteria, with the exception o f TCE and FC-143, whose maximum concentrations in industrial process well water exceeded drinking water criteria by factors o f four to five (see Appendices B and C). However, average concentrations in process water at the point o f use (which is a mixture o f 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-impacted 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 FC-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 o f species or habitat, are reflective o f 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 o f field reconnaissance for habitat characterization (April 6 to 7, 1999), principally along the portion o f 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 o f concern for ecological receptors, and groundwater does not discharge to surface water at the site. _. CORPORATE MMSOIATIONCROUP AiM m m M n . Sotoy M i Plata, SUMngXT W Wii |ltH ,W a H ii I M M H f -- : *> C :\M A fm 720Sl7205RFI.O O a29-JU N -9a720a O 'O ASH000304 EID090401 SIG T IO N SIX Screening level B isk Evaluation 6.6.2 Habitat Characterization atthe RBUADP . 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 o f the alluvial terrace on which the main plant is located. A layer o f clean fill 6 to 36 inches thick was placed over the RBL upon closure in the 1960s. The southern side o f the RBL is within the stive 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 o f 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 o f the RBL, the grassy area gives way to natural vegetation o f trees and shrubs. M ajor vegetation species include beech, maples, oaks, ash, cottonwood, black willow, and sweetgum. W ildlife observations, including tracks, burrows, and scat, included small mammals (woodchucks, cottontail rabbits, squirrels) and deer tracks along portions o f the river. It can be aggnmed that other small animals such as mice, voles, raccoons, and various reptile and amphibian species would inhabit the area near the riverbank. Birds observed in the area were primarily bank swallows, crows, and redwing blackbirds. Other passerine birds w ill likely occur during different seasons. Hawks were observed hunting over the area and several species o f 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 die RFI study area. In addition, according to the WVDNR, W ildlife Resources Section, no rare, threatened, or endangered species are recorded for the vicinity o f the Washington Works plant Table 6.9 lists the terrestrial species that are list! 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 o f 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. ASH000305 CONKMATC MMeMMIOM OAOUP | t y M l Wm , BUMwgT f W M ngM , ( M a r* * UMC OOP 6-9C:\M ARW 205\7205RFI.00029-JUN-99\7205\ EID090402 SEG T IO N SIX Screening level R isk Evaluation 6.6.4 Ecological Exposure Pathway Evaluation In conclusion, there appear to be no significant ecological resources or exposure pathways o f concern related to-soil at the SWMUs. Groundwater is not an exposure medium for ecological receptors, because there are no surface expressions o f groundwater 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 o f significant ecological resources in the study area. 6.7 SUMMARY AND CONCLUSIONS Soil at all SWMUs is not a medium o f 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 o f exposure for workers. In wells supplying industrial process water, maximum concentrations o f 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 o f woody or grassy vegetation along the river bank and slopes o f 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 o f the W ashington W orks site. Because o f 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 o f the screening-level risk evaluation and ecological exposure evaluation. 1 ASH000306 CORPORA? RSMSCIATKMCROUP Ai W m n M m m AAM M ^IlHM tCOiinrfAav a rt* M i PU M .au** 2? laMMO? 6-10C:W ARY\7205\7205RFI.DOC\29-JUN*99\7205\ EID090403 SlGTIflNSEVEN Concluslons/Recom m eniiatloiis 7.1 CONCLUSIONS The main objectives-efthe Washington Works RFI were to determine the nature and extent o f SWMU-derived waste constituents, and their rate o f 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 o f these efforts are summarized as follows: 1. Concentrations o f 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 o f horizontal impact (i.e., laterally away from the edge o f a SWMU) o f organic constituents to soils near the SWMUs appears to be minimal. In general, releases from SWMUs migrate vertically downward through the vadose zone to the site aquifer. 4. Concentrations o f 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 o f 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 o f SWMU-impacted groundwater by the production well system and, although not planned, this capture would continue even with a 65% reduction in pumping rates. COHPOJUTS RCMtDUnOM CHOW AwWwwe eeftw w OuftMlOTtf niaW CO Iaiw itfO iw v 7-1C :\M A R Y \7205\7205R FI.D 0C \29-JU N -99\72Q 5\ ASH000307 EID090404 SECTIONSEVEN 7.2 USEPA ENVIRONMENTAL INDICATORS The following summary is provided to address USEPA's newly implemented Environmental Indicator program. The primary objective is to present RFI conclusions that specifically pertain to CA 725-Human Exposure Under Control and CA 750-Contaminated Groundwater M igration 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 Migration Under Control As demonstrated by the site-wide groundwater flow model, current production well pumping prevents off-site migration o f 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: . Continue operation o f the methylene chloride seep collection and treatment system (RBLL1) as a final remedy. M aintain production well pumping at or above 35% o f present levels. Conduct long-term groundwater quality and site aquifer potentiometric surface monitoring to ensure die continued protection o f human health. Conduct long-term groundwater potentiometric surface monitoring to ensure the continued capture o f site groundwater. : It is proposed that this monitoring occur semi-annually. A set o f 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 o f production well pumping as the means o f preventing off-site migration o f SWMU-derived waste constituents. DuPont will prepare a long-term groundwater monitoring plan upon direction from USEPA Region III. ASH000308 7-2C :\M A R Y \7205\7205R FI.O O C B 8-JU N -99\7205\ EID090405 90* 060a ia SiC TIO H EIG H T_______________________________ Balerences Braun, E. L. 1950. Deciduous forests o f the eastern North America. Philadelphia, PA: The Blakiston Company. Carlston and Graeff. June 30, 1955. Groundwater Resources o f 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.I. DuPont de Nemours Co. Washington Works April 1992. (Vol. 1). ______ . 1997. RCRA Facility Investigation Plan, DuPont Washington Works, September 24, 1997. Corporate Remediation Group. Fenneman, Nevin M. 1938. Physiography o f the Eastern United States. New York: McGrawHill. GE Plastics. 1996. Groundwater Elevation Map, June 18-19. Geraghty & M iller, Inc. 1993. CALSTATS: A Model Calibration Utility that Compares ModelComputed Values with Field-Computed Values, 1993. Hamilton, W illiam J. and John O. Whitaker Jr. 1979. Mammals o f the Eastern United States. Ithaca: Cornell University Press. Haskell Laboratory. 1991. Ammonium Perfluorooctanoate (FC-143). HydroTrak, Inc. 1999. ModelCad For Windows: Computer Aided Design Software fo r Groundwater Modeling. 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. U. S. Geological Survey, Techniques o f Water Resources Investigations. Chapter 6-A1. pp. 586. ASH000309 A CORPORATE ftEfcg(NATIONGROUP 8-1C:\MARW205\7205RFI.DOCV3tKIUN-99\7205\ SlCTIflMEIGHT 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 Guidefo r MODPATH, Version 3: A Particle-Tracking Packagefo r MODFLOW. Pollack, D.W. 1989. User's Guidefo r MODPATH/MODPATH PLOT, Version 3: A Particle Tracking Postprocessing Packagefo r MODFLOW, The United States Geological Survey Finite-Difference Groundwater Model. USGS Open File Report 94-464. Schultz, R.A. 1984. Groundwater Hydrology o f the Minor Tributary Basins o f the Ohio River West Virginia. ' Smith, Roy L. March 7,1995. Risk-based Concentration Table January-June 1995. USEPA Region in memorandum. USEPA. 1986. Test Methodsfo r Evaluating Solid Waste Physical/Chemical Methods. SW-846 Third Edition - .. 1989. RCRA Facility Investigation Guidance. Office o f Solid Waste EPA/SW-530-8931. _. July 27,1990. Proposed Rule: Corrective Actionfo r Solid Waste Management Units at Hazardous Waste Management Facilities. EPA/SW-530-90-012. .. November 1992. RCRA Groundwater Monitoring: Draft Technical Guidance. Office o f Solid Waste. EPA/530-R-93-001. .. May 31,1994. RCRA Corrective Action Plan (Final). USEPA Directive N um ber 9902.3-2A. - December 1996a. Recommendations o f the Technical Review Workgroup for Lead for an Interim Approach to Assessing Risks Associated with Adult Exposure to Lead in Soil. Technical Review Workgroupfo r Lead. . 1996b. Soil Screening Guidance: Technical Background Document. USEPA/540/R95/128. CORPORATO REMEDIATION(IA0UP A iM m lM M AA* fC O fm rrf Oraw Beto rW P Ita,g tA *iZ7 8-2C:\MARYV7205\7205RFI.DOCV29-JUN-99\7205\ ASH000310 EID090407 SECTIOHEIGHT References 1997. Ecological Risk Assessment Guidance fo r Superfund: Process fo r Designing and Conducting Ecological Risk Assessments (Interim Final). Environmental Response Team. Edison, NJ. ______ . May 5,1997. Verification Investigation Report Notice o f Deficiency. Letter from Mary Beck to W. M. Stewart. . April 1998a. Guidelines fo r Ecological Risk Assessment. Risk Assessment Forum. USEPA/630/R-95/002F. ______ . 1998b. Ecological Risk Management Principlesfo r Superjund Sites (Draft Guidance). Office o f Emergency and Remedial Response. USEPA Region E l 1993. Selecting Exposure Routes and Contaminants o f Concern by RiskBased Screening. Technical Guidance Manual. USEPA/903/R-93-0Q1. ______ . 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 o f Natural Resources (WVDNR). May 12,1999. Correspondence from Barbara Sargent, Wildlife Resources Section, to Don Spires, URSG-Woodward-Clyde. West Virginia Division o f Environmental Protection. M ay 1, 1996. 47 CSRCO, M onitoring Well Design Standards, Office o f Water Resources. A SH 0003U 4Q9B Oi^ttnenmWCOlmmttOnm 8-3C:\MARY\7205\7205RFI.D0030-JUN-99\7205V EID0904Q8 rs oOm o * EID09Q4Q9 FIGURES lilllB ay p iP iJ EID090410 ASH000313 GENERAL ELECTRIC PLASTICS CO. N o rth w e st Pipe Company 8, AGA Gas (located to the w est o f GE) IB9B) DISTRIBUTION CENTERS OF PARKERSBURG (WAREHOUSING) ---- 1------ PROPERTYL IE Shell Chemicals (lo c a te d 0.5 miles u p river) Huntsman Chemicals (lo c a te d 1 mile u p riv e r) ;I / DuPont W ash in g to n W orks Local L a n d fill Amoco (lo c a te d 10 miles u p riv e r) \ I II \ m it1 ^ N EARBY INDUSTRIAL LAND U SE SCALE C o rp o ra ta nam adW an Q ram DuPont Washington Works 800 0 800 *****mdP*-CMmm* Washington, West Virginia Figure 2.1 EID090412 E T fr06oaia -* SCALE om OHE CHKDs m BAIE: RCK: 05/24/9# 0 7205C006 MKHU 2 .4 ' "* ; - -5* ASH000316 UMMEMffCNM0MNMKUOTU.UMHMBMttl* o M ^ w g w a a ia a B W t b t o w n a ia a y mmb il -- mi m n i w w w n w r o n t w i f> w s m b ^ % 1 * M W fltt.S N M B UNTS S U H 3 4 rvwM c tarai w . n e to t m a u n a %fia Colporato Remodation Group An jUHann tifa m a DuPcmi and Ita W--C Diamond Qnrap Qartay MAI Piaza, Building 27 wamfagton, Ddawara 19880'-0027_______ IT IL E : CROS DuPC DWN: DEL CHKD: SJO W A SI- DATE: 6/25/99 D E S .: APPD: REV.: 0 F IL E N U M BER: 7205B007 FIGURENO.: 2 .5 EID090414 E ID 090415 c O (Down River) West A 20 FT, 630- 620 - LEG EN D S E U a E3 CROSS SECTION A - A1 E. I. du Pont de Nemours & Company, Inc. WASHINGTON WORKS PLANT .WEST VIRGINIA 1991 T o p o o i- O L S a n d - S M .S C .S P 5 FR Q Q ] S it - M L S a n d a n d G r a v a i- S W .G P .G W .G M BS EZD P a a t- P T B e d ro c k I7 1 C k i - a f S t a t ic W a te r L e v e l, D e c . 1 9 9 1 A p p ro x im a te G e o lo g ic C o n t a c t -- - S t a t ic W a te r L e v e l, In fe r r e d G ro u n d w a te r F lo w D ir e c t io n F IG U R E 2 .5 A T179X C A (Up River) P r o d u c t io n T r i s t ELL 3 3 3 t a s l Figure 2.5A E ID 090416 CD IO IN m o f&=f) mx (9 OQ 3 O cn IMOI , PLEISTO CEN E AGE Ohio- RJ.lv eur T.errauce DJeCpousjita - 9 `9 ' 9 ] ' ;0 ; - - ; : - ;0-Q- .'o- ;Cku.'c>' 3 : a s -z n a i a : ' <Kv :D':q - ffe. 1m 'o-'- : , / . P 5 * P '.9 ;/. ' 9 4 ' 9 ? : t ? P y . :. / :0:-c>- ;-0;.'o-;0/Q--e>*. iQ-o'-fai- P r-y i IP." - ' 9P: *- ' -VO'****--'o ^ V - . Ai: P:. - -'9 9 ' f 9 :V' :.M fb - 3.": Lx'P::'- :* : ASIIGQ0317 HSW 3 N0LLVA313 N ( E 2.5C North c 20 FT n 7 9 X G C lthLEGEND: f f l E D .H t 640--1 1_ 285 F S ii 1)1)01ISV ; ' : P . ` * U I * * EID090417 CROSS SECTION D - D* FIGURE 2 .S D c E. I. du Pont de Nemours & Company, Inc. WASHINGTON WORKS PLANT , WEST VIRGINIA uggjLE G E N D I T o p e o - O L 1 = 3 F ill O (S 3 S a n d - S M .S C .S P E D ] S H M L S a n d a n d G r a v a i- S W .G P .G W .G M TW-22 1991 Pact - PT V y i B e d ro ck m C la y - C L 1 " S t a t ic W a te r L e v a i, D e e . IS S I A p p ro x im a te G e o lo g ie C o n t a c t S ta tto W a te r L e v e l, In fe rr e d G ro u n d w a te r F lo w D ire c tio n 7179XCD South D' RBLMW-9 B-29 BGMW-2 B -33_ BD-22 TB-80 vt/T-O', ......O '.. ,,0 ' .'R.', .0', .'R.'i ; : R ^ : `:P O ;; '.:R.;: ; ;p _ a- ., O '.. ao. . , "a0.'.. : :9'.: `. :<=>'.<d>: ;o',: : ;9'.<? :i. ;o',: ;o',: ' YiR.iYiR.Yi'.'iP.yi'' -,;P .',, 'a *',m i'.O/.'. :C .........;.;...'..|.R.....[-.`H. ' Jd' o'.,;<,o ; ;o',:. i , | .:<3.;.;-<3'.- :9'. '...O'.v', '. n..O' VA.V.......v..A0..'.V. .' o-<?:' -d ' I , .o '.;r 1! ' SL ;o',:..', ;o'.: 'o-.: 'o'. : 'G.'.'i'.y.'.'/.t)'.;g: ':-.6yo; .v.oyG: .y6'-:G: .Y^ Oa ..'R- i', ;R.io-, ;R..;<6 : !9'.<?:. :o\o: ;'. ;o'.:. ;o\: ;'. ;o',; 'G.'.v.yG.v G/y'.oy.'.'^ y " y.;. ' Q r` :RY:Y:RY:' 'G.'.'^yG'.'i'.; ';'.RYa'.:Y; :iq~ To(a5J :g.'.;:'6'.:cs, 69 :o'jd>:;*, ;o\o; , ;\OTt i .".yG.'.'l'.'.'G, = oyG ..yyo^yyG v;^ p .'.^ .'.O :o\: 'o'.; '. :<=>\: ;o'.: '. `o-.' \ ;o\: *, o'.: = .y,t)'.:.v':. V 't ^ .v t y . :o\d>:`.,1;o\:' = ' \ : ; . ;o',c!>! . ]di`. ;o'.: -'. ;'.: '. ;o".: 3 L3 > X irP ELEVATION ( f e a t MSL) C R O S S SE C T IO N E - E' E . I. du Pont de Nemours & Company, Ine. WASHINGTON WORKS PLANT , WEST VIRGINIA LEGEND! Bg OLT o p a a t- S U r~1 Send- SM.SC.SP mD - . E3 SandandGrami- SW.GftGW.GM 1991 S Foot-P T EZ3 [Z2 W- CL StaHo WaterUni. Dw.DI ; ASptaptriacdWrnaatteerGLeaomlobgiMeConoanctiact r FlowDtraeSan FIGURE. 2.5E 7179XCE South E' BGMW-7 630 BGMW-1 BGMW-5 BGMW-6 BURNUSIGROUND - UNIT H-W BGMW-4 BGMW-3 im m illili 620 . . 'o '. : ;o ' . ,*--*ss,', ),0'*'iod' cp.;!O*,t;o1\0<?; \ ;o\o, --; ;'< I; ;o\: 'P''o.''ji?r .:cy.v.b' q; '.'G;.v'/G' '/. ip^n'.y 'gWsb.V.qYCS; 600- & ? #&:'J[''.?;</?; -, '.Py.'.''. `P-\, ;o;. ''. ;o; S ' l'. ;P.'|c :.o-.v '* 'rb- '0/ ; ;o\< :; ;o\0: TIf!fj i> .'G.'.V.'.'0 . ,. ji- . :H-" . -o>a . -.o5s:i*''y0''.'v';'.6'- : .v.6y:.;:^yQ .. i'-O.'-y--9'<V 580 r r *. . o 1, . ml '.'-O'**''' ' 560 ' *.. ^ > 0 P - *. `c V c ^ p a e v t v * . ." w a * n 1. '. ' . A '. \ A \ \ ` . ' . A * . * . ' . ' . .1 /.V ' * *.v ' ..v .v * *>v v > { u r \ i u \ i i m \ w -i-w * ,'7 , S a> > 1 8 ASH000321 EID 090420 i i SID 0 9 04 2 1 c c SID090422 ASH000323  EID090423 ASH000324 g* a jn S lJ ASH000325 EID090424 LEGEND , D08-MW01 J17-PW01 M16-MW01 = EXISTING W ELL = PRODUCTION WELL = C-8 WELL ^ E13-MV01 as ^ Y04-SB01 RBLU =i =i N20-SB01 o * R FI HAND AUGER iK APPROXIMATE AERIAL EXTENT OF SOLID ' MANAGEMENT UNIT A-3 K 0 4 -: p jg j 5 8 2 . 0 ' i i 1 A u\ ASH000326 630.1 X / >W-CDimmmdOmm 'laza. B id d in g 2 7 Jew 19880-0027 METHYLENE CHLORIDE IN SOIL DuPONT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA T m -------------- 1 I wot O V S 8 /M nem oo* 4 .1 EID090425 H04-SB03 CONSTITUENT Freon 113 P/F UNITS Total D04-SB03 CONSTITUENT Freon I3 RIVERBANK P/F UNITS : LANDFILLTotal gug/kg) S-HO4-SBQ3<6-0> S-N04-S803C14-16> 10/10/98 10/10/98 Prim ary Primary UNIT A-3 390 J 400 J "1 N04-SB04 CONSTITUENT Freon 113 P/F UNITS Total S-M04--SB04<0-2> S-M04-SB04 10/12/98 10/12/91 Primary P rln a r 210 J ---------------- DENT P/F UNITS S-T04-SB0KD-2) 10/10/98 Prim ary Total <"8/<a> 170 J ASH00Q327 K04-SB01 CONSTITUENT P /F UNITS S-K04-SB0K12-141 10/12/98 Primary Freon U3 T otal ft/i<a> V I IH r v 340 J -r^ V05-PV01 L06-SB01 CONSTITUENT Freon 113 S-L06-SB010-12) S-LOfr-- 09/25/98 09 P/F UNITS Primary Pi T otal <ua/ka> 9700. oL8-SB02 r LEGEND , D 0 8-M W 0 1 = EX IS T IN G W E L L J1 7 -P W 0 1 = PRO D U CTIO N W E L L ^ E13 -M W 0 1 _ iw d s H o n G n w p -- R rw M e m W-e Stamane Amp ^ Y 0 4 -S B 0 1 1 3 z a v B u ld in g 2 7 --------------- m o ra 1 9 8 8 0 - 0 0 2 7 150 RFI SO ILS MAP FR EO N 1 1 3 IN S O IL DuPO N T WASHINGTON W ORKS W ASHINGTON. W EST VIRGINIA 1B B S ------------- H Q -------------- W N IH k ' U R * - wer j s /x /m TM O TK j 4 .2 *" EID090426 t>z> ooK to8-oo EID090427 eo u 3d fa ASH00329 EID090428 f 'c LEGEND D08-MV01 J17-PV01 * M16-MV01 EXISTING WELL = PRODUCTION WELL C -8 WELL EI3-MV q Y04-SB o N20-SBQI = R FI HAND AUGER APPROXIMATE AERIAL EXTENT OF : MANAGEMENT UNIT A-3 N05-SB01 CONSTITUENT T richtoroethsne S-N05-SBOK2-4) S-NO p / r UNITS 09/88/98 Primary 0 1 T otal <ua/ko> 8800. -EL. 582,0' U03-MW01 U04-MV01 . U04-SB01 "^r V04-SB01 /VOUUUUJJU V06-MV01 L06-SB01 CONSTITUENT Irk n a ro rth e rw I \l p/r u T o tal (u 1, U] It o L08-SB02 R o u w d M k x t G ro u p i Hm n M m m <Ite W-CDimmnAdram .Mn.SIDPatlaawzaareB1u9M8h8g0-020727 O 75 150 FEET RFI SOILS MAP TRICHLOROETHENE IN SOIL OuPONT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA W M 1I--- 1- iear \ 9s/\9/m TMnOHL 4.5 EID090429 <c Y04-SB01 . RFI BORING APPROXIMATE AERIAL EXTENT OF SOLID WASTE MANAGEMENT UNIT A -3 TEMPORARY V O X RIVERS LANDFII UNIT A ASH000331 / \J r AI06-SBU CONSTITUENT T rich lo ro eth en hJ AG07-MW0I a te : P /F UNITS S-A I06-SB O K 0- 0 8 /2 3 /9 8 P rip sa ry T o ta l <un/kg> ' 16QJ C \ 4 zo 9 -M w o i^ |M M d a flo a Group Z09-SB01 uKm m M m m Ib M H M N lA i a Plaza BuMIng 27 R F I S O IL S M A P TR ICH LO R O ETH EN E IN SO IL Du PO N T WASHINGTON W ORKS W ASHINGTON. W EST VIRGINIA S 3 -------- p i --------Y u Z j ta/svm azau j 4M EID090430 ' 'c zstoooHsv f" II C SU M ? Corporate Remediation Group A iA R m g t M w M Dopantm i fhm W-CDkumnd Snap BtrityM M Pitza, BuMhQ ST W Um kgfan,D dm m n 16880-0027 43 Soil Results (mg/kg) 10-220 221 -1000 1001 -2400 2401-11000 11001 -48000 >te results for one sam ple on 39 depth range IH SO pmu* SO REV. .1/99 W ash.apr 4.7 EID090431 F ig u re 4.7 -. ASH000333 Corporate Remediation Group AnAlEtnca batwaen Duponttnd Th* W-C Diamond Group Btrtoy MSIPluzt, Buidlng 27 Wilmington, D tlm ven 13830-0027 61 -170 171 -600 601 -1200 . 1201 - 9500 Multiple results for one sam p le scation indicates that m ultiple o il sam ple were collected fo r he soil depth range DE&: so .. IP P O : 0 so m tz 31/99 1 HLE NUMBER W ash.apr H O U R S MOt: 4- .8 oe 9i U I EID090432 c( ) ASH000334 / 0 $$ e / 1) il 5-110 11 -280 51-1800 results for one sam ple indicates that m ultiple pie were collected for lepth range An Alliance t Duponttn d The W C Diamond Group Barioym P ira, Buiamg 27 WSmington, D tltw tn 19820-0027 4 RJH oe s z so APPO: SO SO REV J .3/31/99 1 RLE NUMBER: W ash.apr ROUSENOJ . 4 .9 EID090433 I Y05-MW01 , *0 c 630 ASH000335 Z06-SB04 Y07-SB01 G GRDUND -14 Y07-SB01 CONSTITUENT S-Y07-SBK8-10) 09/2 2 /9 8 P /F UNITS P rln ary C arb o n T e tra c h lo rid e T o ta l <UB/ k 9> 0053 LEGEND D08-MV01 J17-PW01 N2-SB01 o = EXISTING WELL = PRODUCTION WELL = RFI HAND AUGER Jv SCALE nwdvfSon Gran mfm-CMDktannmumdftnfi Homo, BuMtng 27 "magra 19880-0027 CARBON TETRACHLORIDE IN SOIL DuPONT WASHINGTON WORKS WASHINGTON. WEST VIRGINIA j-i "M .. bihiiii iiW I*- w I WK/m I -- I 4.10 EID090434 Carbon TetracKloride R esults (ug/l) .1 2-16 + W ells not Sam pled > CO go o upO>J On F ie u re 4.11 D Corporate Remediation Group Dupentend The W-CDiamond Group BarleyUHPlaza, Bidding tT WUmington, Detonate 1$BBQ40Z7 ea: 4A j h GB WPO: 3B GB m il 1/19/99 1 RLE NUMBER Acid.apr neuBENO: 4.11 EID090435 ASH000337 EID090436 c ASH0G0338 ,-A achloethene Results (ug/l) \\ \ \ 3 - 51 ' 2 6-8 9-17 18-240 Corporate Rem ediation Croup An Alliance between Dupont and 77 W-G DiamondGroup BarleyMillPlaza, Building 27 Wilmington, Delaware 79880-0027 1BIJH f3 '99 CE&: GB APPOt: GB REV.: 1 RIENUUBSfc A cid.ap r FIGURENO- 4.13 - e E ID 090437 ASH000339 Tf I s E ID 090438 ASH000340 E ID 090439 hloroethene Results, (ug/l) 1 -5 6-36 37-63 64-150 151-670 ASH0341 h ---------- vm peg i m a m Corporate Remediation Group * RJH GB AnAleiKobttwman HKft: APPO: Duponttit Th W-C DItmand Group GB GB Bwtoy MBPa, HuBtitog27 WBmington, Q*tamn 19860-0027 ATS 5/19/99 1 RUNUMSeC Addapr 4.16 E ID 090440 ASH000342 I E ID 090441 ASH000343 E ID 090442 r. S\ E ID 090443 ASH000344 ASH000345 EID090444 A SH 000346 ---- osco MODEL DOMAIN utadtailon Group E . I.. DuPont de Nemours & Co. DuPont Washington Worte N * r-c W M * SOURCE: USGS UTTUE HOCKINC QUAI 7.5 MINUTE SERIES (TOPOGRAPHIC) p|aM< 27 ______________________ iM >ar 19B8N027 Washington. West Virginia H SH T K- /o/~ 9 .1 EID090445 ::i{iK;5:B5;:na!:K:a:::::iiK::::: ss'Sis<s$^^^plEIS^^BI|^|lS|i|i AC****X*at*A*l*B**.*****.*W**WW*3aW***>**W->M.r*** ; M M l l * M * * * * * M * * * M * " " " ,r" , * * * * ` ,* M * " * Wi,r* ` -- " * * ' " ** fca * * x j* * w * B i R * a * * * C * * * * * . .... XJ*w<******^*J'*****'***************> * * * * * * * .* * * * * *******'***2*m****iiij555i*552*5'i5253**i*52*2' WB* * * * * :* * i 5 * * 5 * 5 i 5 * * ' * * * X ' : * * *-* .>* .......S...*........'.*..--- * *---*--*--*-------*---*--*- -]-- * * * * * * * * * * * * . 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" " ^ " " ' U " b" H ' H S H - b b i^<h>(*b * .X * * * W * M R X * .* * irR X X X X * * * * * - Jr > J2 * f 5 x x * * * * : * * * > * * * * * * * A * * * * A * * * * * - * * * * * . * <M H >xaA lM r* * 4 X i T " r x r x m 1 i R Ra * * Aa* ML a R#xRRKRxW aJ . ***xR *a*M RA>v|r*aa<xi kh > *A2- J J k :H ::H : b : ; : b : : : :! :::: i M * * * 4 W -* R * * a ii* ir a * * * * H a it R * * rBKkr . .* M R H . v a i ir aa R a k aa ai K f> * a -* K R * aaaR H a * x aj< * a* K a x * x a x * * * :JibZ a .* * -* * * * '* * -*< ** * ** v n * > a * a ^ M R a R i * J ; : 2 K K i * * K 5* 5 **x * * * ; f 5 S ; i ; * ** * * L,xk*",`*'a'w**<'a'**'a**a *** <*< ii'** a aa* 'X* **i * a k a ia a * * * * x * # ii a * a a* *x a S ^ a > * K a ii * wi K CaCa4*xK*BCCx*Cv***B***Ca**AR*x**M*M*K'*A**i*<?jMJ. 5raJA*;l;*ZRX^** *a* n .V* a *JM f*fai*a* i ii h a.a* a a' a* B .* i r x * ' B * a - Bxr* a x * * x * * x * p .a j ? ; 3 3 Z m . x ii x h A * R k . t x A a B A R a a V B 4 . * a > x .* k u rJ2 ;2 2 i Tk M a * a n k m * n n m a a * a M M * * a * a * * a * * n u M i i n n a i * 5 ?^z d---- - "i-il-Ur i iXX **lu* -b----R--X- K * M * x . c x * > x x ' x a . a b xbJ * * * * * * J J J J J J " ; ; ; H ;S ! ; 5 : : e;. .,.,....... _ ,* R* R B * B a .* * B x W A 5 B * B a * * a B R a JiB iw B x a a x a * 2 j;2 2 3 K Rx R A a- *R!JI X*; Kai ia -iRBiiwB*iK:Bas a: R a a a * a f: a a: w: !B m: n .! i iaf ia :a a M i c i i * * *- - t*. "f c a` RHxM BB ' -~ - M x jiw x a * a a * B * * * a a * A ;.; r H H S ^ H S ijllg : *2*i5*ii5i*iici***5**ii^lc c a c * a a B a c a . * . . .C. K. .. .*_____ *____R.B__B__*___ * a B B a a x a J t* * a a * ;i' J t i j n t M k f m a . b . J _ _ _ _ IC B Xl X ci v l * l i l B iB a m a a * a**** liif t Ma a A R R c a a M a * * * an d a * . B B B -A A A C 4 B a * * - * * * C C R B i a a K K X J I ^ ____ _ * * * 3 2 ' . Sc e5 *i *S ^j 2 *2a * * /3( ta M aka* i55a ** ^: J* ;* * * A -a ta ji*ilN a a a c c*c*B *a * rc A c a M a R B ' C R B *' f k * k * *** * * * * * ] _ * * * j ; j k ! ; ; ; B a a iia k ia x B a B B K C A y a x a a .c a k U c c B U R B B B X B B c a B -a B B c a B c a c B B X R B a A B X X irc a R a a c -B a ia x x tiiiitiR B a a x ii * *: :;;i;'iv;;'ir:s;n;;H;H;;ri..;.:.:.:.::.:;::" ::;: ";::* a a c K B B a a R B a B k C B c * c a a R B c x B x a . H a B * M a a a a a c j r * t * c f r * '* J J J J - J 2 i j B c a R a a a B B a * a e ------- - -------- -- -- -------- - * B U * * i r * * A x * * i t B t t B a * W c # * * * i < * a . * * * * * * * U R v m a J n s t n u k -t---n----n- --n i -n---n----a----M--- --n----M-------m--- -H ,M i n K iu * n j **B>^i xm*a * * B**.a* ! M ODEL GRID m f^ 0B672IS99| G rou n d w ater F lo w Model DUPONT WASHINGTON WORKS WASHINGTON. WEST VIRGINIA Ci m. <o I U* ASH000347 E ID 090446 SI . 1 (* f G ro u n d w ato r Plow Modal DUPQNT WASHINGTON WORKS WASHINGTON, WEST VIRGINIA E ID 090447 F ig u re 5.3 ! (^eooousv Groundwater Flow Modal DUPONT WASHINGTON WORKS WASHINGTON. WEST VIRGINIA m a % ft E ID 090448 i E ID 090449 ASH000350 Figure 5.6 Groundwater Model Summary DuPont Washington Works Parkersburg, W est Virginia Calibrated Groundwater Model - February 1,1999 Data Set A SH 000351 im M odel G roundw ater E levation {feet MSL) E ID 0 9 0 4 5 0 v v5 u 3 & E ID 0 9 0 4 5 1 . .jure 5.7 GroundwaterModel Summary DuPont Washington Works Parkersburg, West Virginia SENSITIVITY A N ALYSES S000HSV 555 560 565 Target Head (feet MSL) Note: Best fitlinebased on linearregression ofdata set. C a lib ra te d M o d al H e a d s P u m p in g -1 5 % j P u m p in g + 1 5 % * R h m ratag e -2 ft X R iv e r sta g e + 2 ft p R iv e r C o n d u cta n ce -5 % P R iv e r C o n d u cta n ce + 5% O C o n d u ctivity -5 0 % O C o n d u c tiv ity + 5 0 % A R ech arg e -66% A R e ch a rg e +66% --------- T a r g e t H e a d = M o d e l H e a d ----------L i n e a r ( P u m p i n g - 1 5 % ) ----------L i n e a r ( R i v e r s t a g e + 2 f t ) ----------L i n e a r ( R i v e r C o n d u c t a n c e + 5 % ) -- L in e a r (C a lib ra te d M o d el H e a d s ) L in e a r (R iv e r C o n d u c ta n c e -5 % ) ----------L i n e a r ( R e c h a r g e - 6 6 % ) ---------L i n e a r ( R i v e r s t a g e - 2 f t ) ----------L i n e a r ( C o n d u c t iv i t y - 5 0 % ) ----------L i n e a r ( C o n d u c t iv i t y * 5 0 % ) --------- L i n e a r ( R e c h a r g e + 6 6 % ) --------- L i n e a r ( P u m p i n g + 1 5 % ) F ig u re 5.7 / I I H a oVO oI* U1 to t ,,,_re 5.8 GroundwaterModel Summary DuPontWashington Works Parkersburg, West Virginia M odel Verification - Novem ber 1997 & Novem ber 1998 Data S e ts Nov-98 Pumping 20% less A Noves Nov-97 Pumping 20% less Nov-97 -T arg et Head => Model Heed -L in ea-(Nov-87 Pumping 20% less) -- -- Linear (Nov-98 Pumping 20% less) -- Linear (Nov-88) U near (Nov-97) SOOOHSV Target Groundwater Elevation (feet MSL) Note: Best fitlines based on linearregression ofdata set. F ig u re 5.8 ASH000354 E ID 090453 SOURCE M A T E R IA L S It* FO R M ER B 6 A N D RBL/ADP WAY ST A T U S ECEPTORS FUTURE RECEPTOR tiverbank spassar C onstruction W orker O 0 O 0O 0O 0O ASH000355 NOTES: o DUPONT WASHINGTON WORKS RFI WASHINGTON, WEST VIRGINIA Potentially Complete and Potentially Complete but b Blank Indicates an Incomp DATE: 5 4 0 4 0 DATE: 5 00 4 1 RIVER BANK LANDFILL AND ANAEROBIC DIGESTION PONDS dAN EXPOSURE PATHWAY EVALUATION F U E NO. Md06W720589 F IG U R E 6.1 V 2 a SAIS99V44d04w7I_05\M<Hl*jtU\HUMAN (3JUOV99M:4S PM Page 1 o f I E ID 090454 s . n m u t n w n j I M r t, M c o n n u u m w p m Page 1 o f I E ID 090455 ASH000356 ASH000357 E ID 0 9 0 4 5 6 TABLE 3.1 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Background Burning Ground AE11-SB01 AI10-SB01 AP10-SB01 E13-SB01 G17-SB01 N20-SB01 P14-SB01 T14-SB01 Y14-SB01 Z11-SB01 AA06-SB01 AA07-SB01 AA07-SB02 AA08-SB0J AA08-SB02 AC06-SB03 AC06-SB04 AC06-SB05 0 59 0 0 0 0 0 0 0 0 76 0 0 6 14 20 40 64 0 0 4 0 4 0 0 6 12 34 48 62 0 6 14 34 54 62 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 10 5/98 2 10/5/98 78 10/5/98 2 10/5/98 2 9/2/98 8 9/2/98 16 9 a m 22 9 a m 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 2 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 9/1/98 64 9/1/98 2 9/9/98 8 9/9/98 14 9'9/98 20 m m 42 9/9/98 64 9'9/98 borings.xls ASH000358 EID090457 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Burning Ground (corn) AC07-SB02 AC07-SB03 AC07-SB04 AC08-SB01 AC08-SB02 Y07-SB01 Z06-SB02 Z06-SB03 Z06-SB04 1 Z07-SB0I 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 8 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 62 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 9/1/98 0 2 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.xls ASH000359 E ID 090458 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Burning Ground (cont) River Bank Landfill Z09-SB01(cont) AA04-SB01 AA05-SB01 AB06-SB01 AB06-SB02 AB07-SB02 AB08-SB02 AC04-SB01 AE05-SB02 AF05-SB01 AH05-SB01 A106-SB01 60 0 6 14 30 0 8 20 60 4 10 18 40 58 2 10 18 40 62 0 4 10 14 20 40 60 0 4 0 20 28 0 34 58 0 30 0 4 0 18 36 48 60 Page 3 of 5 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 9/3/98 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 9 4/98 6 9/4/98 12 9/4/98 16 9/4/98 22 9-4 '98 42 9'4'98 62 9/4/98 2 9,27 98 6 9/27/98 2 8/21/98 22 821/98 30 8/21/98 2 822/98 36 8/22/98 60 8/22/98 2 8 22 98 32 8/22/98 2 10/14/98 6 10/14/98 2 8/23/98 20 8/23/98 38 8/23/98 50 8/23/98 62 823 98 borings.xls ASH000360 E ID 090459 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT W ASHINGTON W ORKS PLANT River Bank LandfiIl(cont) KM-SB01 L04-SB01 L06-SB01 M04-SB02 M04-SB03 M04-SB04 M04-SB05 M06-SB02 N04-SB01 N04-SB02 N05-SB01 004-SB02 004-SB03 Q04-SB03 S04-SB02 0 12 0 S 0 10 22 66 0 8 14 0 6 14 0 10 2 6 12 2 8 20 66 0 12 0 8 14 2 8 20 70 0 6 14 0 10 14 ,0 8 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 9'28'98 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 10'12'98 2 10/11/98 10 10M1/98 2 10/11/98 10 10/11/98 20 10/11/98 borings.xls ASH000361 E ID 090460 BORING AND SAMPLE LOCATIONS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT River Bank LandfiIl(cont) S05-SB02 T04-SB01 U04-SB01 V04-SB01 YO4-SB01 Anearobic Digestion Ponds P04-SB02 PO5-SB02 R04-SB02 '2 '. ' 4 9/26/98 10 12 9/26/98 40 42 9/26/98 66 68 9/26/98 0 2 10/10/98 10 12 10/10/98 16 18 10/10/98 0 2 9/30/98 4 6 9/30/98 16 18 9/30/98 0 2 9/29/98 4 6 9/29/98 18 20 9/29/98 0 2 8/20/98 10 12 8/20/98 30 32 8/20/98 0 2 10/9/98 8 10 10/9/98 14 16 10/9/98 2 4 9/24/98 22 24 9/24/98 42 44 9/24/98 68 70 9/24/98 0 2 ]0'9'98 10 12 10'9 '98 18 20 10/9'98 ASH000362 Page 5 of 5 borings.xls E ID 090461 TABLE 3.2 ANALYTICAL PARAMETERS BY SWMU RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT River iBank Landfill/ Anaerobic Digestion Pits /S . Polyacetal Waste Incinerator Burning Ground . Soil ' Kfethylene chloride Tetrachloroethene Trichloroethene Freon-113 FC-143 Arsenic Barium Cadmium Lead Nickel ' Groundwater Methylene chloride Tetrachloroethene Trichloroethene FC-143 f Soil 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 Soil Carbon Tetrachloride FC-143 Arsenic Barium Cadmium Lead Nickel 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 6010 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) ASH000363 Page 1 of 2 tab!3.2.xls E ID 090462 (Ili Burning Ground (ont) 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 Methylene chloride FC-143 . Arsenic Barium Cadmium Chromium Lead Nickel Groundwater Methyiene chloride Tetrachloroethene Trichloroethene Freon 113 FC-143 Arsenic (dissolved, total; 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) 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 -- -- -- -- ... RBL = Riverbank landfill (SWMU A-3) ADP = Anaerobic digestion ponds (SWMU B-4) BG = Burning ground (SWMU H-14) PWl = Polyacetal waste incinerator (SWMU C-6) /' Page 2 of 2 tab!3.2.xls ASH000364 EID090463 r\ TABLE 3.3 NEW WELL CONSTRUCTION INFORMATION RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Borehole ID W elllD AA04-MW0I. SBOI TW-70 AA05-MW01 ,SB01 TW-71 AB07-MW02.SB02 TW-72 AC07-MW02.SB02 TW-73 AF.11-MW01.SB0I TW-74 AI06-MW01 TW-75 LI3-MWOI.SBOI TW-76 GI7-MW0I.SB01 TW-77 L06-MW0I.SB0I TW-78 M04-MW02.SB02 TW-79 M04-MW03.SB03 TW-80 N04-MW02.SB02 TW-81 N05-MW0l,SB0l TW-82 P04-MW02.SB02 TW-83 P05-MW02-SB02 TW-84 R04-MW02.SB02 TW-85 S05-MW02.SB02 TW-86 U04-MW01.SB0I TW-87 V06-MW0I TW-88 W05-MW0I TW-89 YI4-MW0I.SB0I TW-90 7.06-MW02.SB02 TW-91 /07-MW0I.SBUI rrw-92 /(W-MWOI.SBOI TW-93 Bottom 43 70 72 74 72 72 74 80 77 25 26 26 82 28 80 28 78 27 77 76 90 72 74 70 nppc Diameter H W " SereenLength Size ^ 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2 " 10 2 10 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2 " 10 10 T 10 10 2" 10 10 T 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 2" 10 10 f f 1- S ^ T it m m m m 43 33 43 70 60 70 72 62 72 74 64 74 72 62 72 72 62 72 74 64 74 80 70 80 77 67 77 25 15 25 26 16 26 26 16 26 82 72 82 28 18 28 80 70 80 28 18 28 78 68 78 27 17 27 77 67 77 76 66 76 90 80 90 72 62 72 74 64 74 70 60 70 T -- , -- 1 ' ' : ' -S , 1 .1 . j ; >11 JV L j 1 L-.ii- * -i . ', . - i'V,v' 31 31 28.5 28.5 surface 58 58 56 56 surface 60 60 58 58 surface 62 62 60 60 surface 58 58 56 56 surface 60 60 58 58 surface 60 60 58 58 surface 68 68 66 66 surface 65 65 63 63 surface 13 13 11 11 surface 14 14 12 12 surface 14 14 12 12 surface 70 70 68 68 surface 16 16 14 14 surface 68 68 66 66 surface 16 16 14 14 surface 66 66 64 64 surface 15 15 13 13 surface 65 65 63 63 surface 64 64 62 62 surface 73 73 71 71 surface 60 60 58 58 surface 62 62 60 60 surface 58 58 56 56 surface E ID 0 9 0 4 6 4 S9000HSV Page 1 of 1 RFITABLS.xls r "\ T A B L E 3.4 WELL DEVELOPMENT INFORMATION RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Borehole ID Weir ID AA04-MW0I, SBOI TW-70 Stickup(2.6') AA05-MW0I.SB0I TW-71 Stickup(2.6') AB07-MW02.SB02 TW-72 Stickup(2.5') AC07-M W02.SB02 AEII-MWOl,SBOI AI06-MW0I E!3-MW0I,SB0I G 17*MW,SB01 L06-MW0I.SB01 TW-73 TW-74 TW-75 TW-76 TW-77 TW-78 Flushmount Flushmount Flushmount Stickup(2.IS') Stickup(2.5') Flushmount M04-MW02,SB02 TW-79 Stickup(2.l5') M04-MW03.SB03 TW-80 Stickup(2.05') N04-MW02.SB02 TW-81 Stickup(2.35') N05-MW0I,SB0I TW-82 Flushmount P04-MW02.SB02 TW-83 Stickup P05-MW02-SB02 TW-84 Flushmount R04-MW02.SB02 TW-85 Stickup(2,00') S05-MW02.SB02 U04-MW0I,SB01 V06-MW0I W05-MW0I YI4-MW0I.SB0I Z06-MW02 SB02 TW-86 TW-87 TW-88 TW-89 TW-90 TW-9I Flushmount Stickup(2.5') Flushmount Flushmount Stfckup(2.5') Flushmount Z07-MW0I SBOI TW-92 Stickup(2.4S') Z09*MW0l.SB0l TW-93 Flushmount 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 10/11/98 10/8/98 10/8/98 10/11/98 10/13/98 Depth to 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 `V o m 30.85 64.30 64.25 62.60 60.30 62.10 63.50 72.35 68.20 14.55 14.45 14.80 71.35 27.10 69.00 14.45 66.70 11.45 65.95 65.10 77.75 61.65 65.45 57.90 2.37 1.49 1.81 1.79 1.89 1.60 2.17 1.75 1.64 1.78 2.28 2.29 1.80 0.52 1.83 2.60 1.65 3.00 1.58 1.81 2.62 1.59 1.89 1.99 3P 30 20 30 30 20 20 25 25 20 25 25 25 25 10 25 30 20 30 20 20 30 20 30 20 I S ? 5 "IB. `i iiit V. f. J 126 Bailed Grey to brown, silty ? 13.4 Pump/Bail Dark brown, cloudy, silty 16.6 Pump/Bail Brown, cloudy, some silt 16.7 Pump/Bail Brown, cloudy, silty 10.6 Pump/Bail Dark brown, cloudy, silty 12.5 Pump/Bail Brown, cloudy, silty 11.5 Pump/Bail Dark grey to brown, some silt 14.3 Bailed Brown, cloudy, silty 12.2 Pump/Bail Brown, cloudy, some silt 14.0 Pump Light brown, cloudy, trace silt 11.0 Pump Brown, cloudy, trace silt 10.9 Pump Light brown, cloudy, trace silt 13.9 Bailed Light brown, cloudy, some silt 19.2 Bailed Dark brown, cloudy, some silt 13.6 Bailed Dark brown, cloudy, some silt 11.5 Pump Brown, cloudy, silty 12.1 Pump/Bail Brown, cloudy, silty 10.0 Bailed Brown, cloudy, silty 12.6 Pump/Bail Dark brown, cloudy, silty Il I Pump/Bail Brown, cloudy, some silt 11.4 Bailed Dark brown, cloudy, silty 12.6 Pump/Bail Brown, cloudy, silty 15.9 Pump/Bail Brown, slightly cloudy, some silt 10.1 Pump/Bail Dark brown, cloudy, silty i E ID 0 9 0 4 6 5 99OOOHSV Page 1 of 1 RFITABLS.xls TABLE 3.5 GROUNDWATER ROUND I DEPTH TO WATER MEASUREMENTS RCRA f a c il it y in v e s t ig a t io n DUPONT WASHINGTON WORKS PLANT ASH000367 Page 1 of 1 RFITABLS.xls EID090466 TABLE 4.4 TRICHLOROETHENE RESULTS FOR GROUNDWATER SAMPLING RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT Groundwater Results for November Sampling Groundwater Results for February Sampling AA05-MW0I L04-PW0I I.06-MW0I M04-MW03 N04-MW02 N05-MW01 P05-MW02 P06-MW02 P08-MW01 Q04-MW02 Q05-MWOI V05-PWOI V06-MW01 W05-MW01 1l/l 1/98 23. 11/18/98 5. 11/13/98 61. 11/12/98 1. 11/12/98 39. 11/13/98 800. 11/13/98 110. 11/13/98 400. 11/13/98 35. 11/13/98 3. 11/13/98 130. 11/18/98 22. 11/16/98 150. 11/17/98 27. UU/L 1. UG/L 1. UG/L I. UG/L 1. UG/L 1. UG/L 25. UG/L 2. UG/L 10. UG/L I. UG/L 1. UG/L 5. UG/L 1. UG/L 1. UG/L 1. 5 5 5 5J 5 130 10 50 5 5J 25 5 5 5 MCL= 5 UG/L AA05-MW0I 2/4/99 5. UG/L 1. 5 L04-PW01 2/7/99 5. UG/L 1. 5 } L06-MW01 2/5/99 25. UG/L 1. 5 M04-MW02 2/7/99 36. UG/L 1. 5 N04-MW02 2/7/99 30. UG/L 1. 5 N05-MW0I 2/5/99 670. UG/L 10. 50 P05-MW02 2/5/99 150. UG/L I. 5 P06-MW02 2/5/99 480. UG/L 5. 25 P08-MW01 2/4/99 63. UG/L 1. 5 V05-PW01 V06-MW0I W05-MW01 2/7/99 22. 2/4/99 120. 2/6/99 28. UG/L 1. UG/L 1. UG/L 1. 5 5 5 E ID 090472 L000H SV Page 1 of 1 Gwmcls.xls TABLE 4.5 FREON-113 RESULTS FOR GROUNDWATER SAMPLING RCRA FACILITY INVESTIGATION DUPONT WASHINGTON WORKS PLANT (roundwater Results for November Sampling Groundwater Results for February Sampling Ik/-* fri -ulk .. *. a* V 4 ' L06-MW0I 11/13/98 3700. UG/L 50. 250 M04-MW03 11/12/98 1500. N04-MW02 11/12/98 270. N05-MW01 11/13/98 7100. P05-MW02 11/13/98 1400. P06-MW02 11/13/98 1900. l*08-MW0l 11/13/98 270. Q04-MW02 11/13/98 860. Q05-MW01 11/13/98 2200. S05-MW02 11/13/98 130. U04-MW0I 11/12/98 13. V05-PW0I 11/18/98 64. UG/L 2. UG/L 2. UG/L 50. UG/L 40. UG/L 20. UG/L 4. UG/L 20. UG/L 50. UG/L 2. UG/L 2. UG/L 2. 10 10 250 200 100 20 100 250 10 10 10 MCL= 59,376 UG/L L04-PW0I L06-MW0I M04-MW02 M04-MW03 N04-MW02 N05-MW0I P05-MW02 P06-MW02 P08-MW0I Q04-MW02 2/7/99 270. 2/5/99 2900. 2/7/99 380. 2/7/99 3000. 2/7/99 210. 2/5/99 3600. 2/5/99 1600. 2/5/99 2200. 2/4/99 890. 2/4/99 76. UG/L 2. 10 UG/L 50. 250 UG/L 4. 20 UG/L 50. 250 UG/L 2. 10 UG/L too. 500 UG/L 40. 200 UG/L 50. 250 UG/L 10. 50 UG/L 2. 10 S05-MW02 2/5/99 80. UG/L 2. 10 V05-PW0I 2/7/99 56. UG/L 10 E ID 090473 H E 000H SV Page 1 of 1 Gwmcls.xls E ID 090474 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-MW0I B07-MW02 AC07-MW02 AE1I-MW01 AI06-MW0I AM07-PW01 EI3-MW0! F06-MW0I GI7-MW0I KI6-PW0I L04-PW0I L06-MW01 L7-PW0I M04-MW02 M04-MW03 M16-MW0I N04-MW02 N5-MW01 N13-MW01 P04-MW02 P05-MW02 P06-MW02 P08-MW01 Q04-MW02 Q05-MW01 R04-MW02 S05-MW02 TI3-MW01 U04-MW01 V05-PW0I V06-MW0I 11/12/98 0.1 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 I l/l 1/98 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 1/12/98 380 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 i 1/13/98 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 SAEOOOHSV 0.1 0.1 0.2 I 0.1 0.1 0.1 0.1 0.1 0.1 2 0.1 1 50 0.1 0.1 0.1 0.1 20 2 0.1 800 100 2 5 50 2 AA04-MW01 AA05-MW01 AB07-MW02 AC07-MW02 AE11-MWOl AI06-MW01 AM07-PW01 E13-MW01 F06-MW01 G17-MW01 K16-PW01 L04-PW0I L06-MW0I L17-PW01 M04-MW02 M04-MW03 M16-MW01 N04-MW02 N05-MW01 N13-MW01 P04-MW02 P05-MW02 P06-MW02 P08-MW01 Q04-MW02 2/6/99 5.43 2/4/99 1.46 2/4/99 0.535 2/4/99 0.356 2/2/99 0.69 2/3/99 0.13 2/3/99 0.082 2/2/99 0.59 2/2/99 0.35 2/2/99 2.11 2/9/99 16.2 2/7/99 5.89 2/5/99 4.91 2/9/99 2.76 2/7/99 17.0 2/7/99 21.1 2/3/99 3.66 2/7/99 329. 2/5/99 815. 2/2/99 29.6 2/6/99 13600. 2/5/99 434. 2/5/99 414. 2/4/99 43.4 2/4/99 994. UG/L 0.028 0.095 UG/L 0.032 0.11 UG/L 0.030 0.099 UG/L 0.028 0.095 UG/L 0.030 0.1 UG/L 0.030 0.1 UG/L 0.030 0.1 I UG/L 0.030 0.1 UG/L 0.030 0.1 UG/L 0.030 0.1 UG/L 0.29 1 UG/L 0.028 0.094 UG/L 0.028 0.095 UG/L 0.029 0.098 UG/L 0.14 0.47 UG/L 0.16 0.53 UG/L 0.030 0.1 UG/L 3.1 10 UG/L 28. 95 UG/L 0.60 2 UG/L 320. 1100 UG/L 2.8 9.5 UG/L 3.1 10 UG/L 0.70 2.3 UG/L 6.1 20 100 R04-MW02 2/6/99 9420. UG/L 280. 950 50 S05-MW02 2/5/99 174. UG/L 3.1 10 0.1 TI3-MW0I 2/3/99 0.64 UG/L 0.030 0.1 0.1 U04-MW01 2/6/99 4.20 UG/L 0.033 0.11 0.1 V05-PW01 2/7/99 12.4 UG/L 0.14 0.47 0.2 V06-MW01 2/4/99 1.91 UG/L 10.029 0.095 Page 1 of 2 Gw m cls.xls |R \ BLE 4.6 FC-143 RESULTS FOR GROUNDWATER SAMPLING rcra facility investigation DUPONT WASHINGTON WORKS PLANT Groundwater Results for November Sampling W 05-MW 0I YI4-MW01 U6-MW 02 Z07-MW 0I 09-MWUl 11/17/98 0.31 11/10/98 12 11/16/98 4.5 11/16/98 I8 11/17/98 0.1 ucT UG/L UG/L UG/L UG/L Preliminary Screening Uvei (SL): 3 ug/L 01 ? 05 05 0.1 Groundwater Results for February Sampling WO5-MW0I Y14-MW01 Z06-MW02 Z07-MW01 Z09-MW01 2/6/99 0.729 2/2/99 4.95 2/4/99 0.803 'm m 2.05 2/6/99 2.74 u g /l 0,078 0095 UG/L 0.030 01 UG/L 0.029 0.097 UG/L 0078 0.095 UG/L 0.029 0.095 EID090475 9l 0 0 0 H S V I 'I Page 2 of2 Gw m cls.xls TABUS 5 .1 Groundwater Modal Summary OuBoat Washington Works Wsrkarsburg, Hast Virginia CALSTATS - - - V a r sio n 1 .3 C a lib ra tio n S ta tis tic MODFLOW BCP rila Hane___. MODFLOW BAS File M.m.___j mod.bcf nod.baa Target Information in..!. mod.trg Model-Computed Ueada in..',' mod.hde NU Hue J0B -M W 01 Z07-MW02 T13 -MW01 016-M W 01 A 009-M W 01 Lia-MWOl V09-MW01 AR09-MW01 AX12-MW01 A J06-M W 01 AOOS-MWOl 004 -MW02 Q05-MW01 P06-M W 02 P08-MWC1 N13-MW01 M16-MW01 AAG4-MW01 AA05-MW01 AB07-MW02 AC07-MW02* AE13-MW33 AI * 0 ] 6.- M W 0 - 1 G17-MW01 2-06-MWrz N05-MW01 P04 -MH02 PC5-MWC2 SOS-MW02 V06-MWG1 W05-MW01 Y 14-M W 0: Z06-MW02 Z07-MW01 Z0S-MW01 Y0S-MWC1 AC05-MW01 AL10-MW01 I07-M W 01 D0S-MW01 F06-MWC1 03-MW01 O05-MWC2 Target Bead Model Head 5 6 1 .0 0 5 6 5 .4 0 5 6 1 .7 3 5 6 2 .9 7 5 6 1 .8 0 5 5 9 .9 7 5 6 2 .3 0 5 6 4 .9 0 5 5 9 .8 3 5 6 7 .3 0 5 5 8 .0 0 5 5 7 .8 7 5 6 2 .9 0 5 6 3 .2 0 5 6 0 .4 9 5 6 5 .7 6 5 6 6 .6 0 5 6 6 .2 6 5 6 8 .5 0 5 6 8 .6 8 5 6 3 .8 0 5 6 6 .8 9 5 6 1 .2 0 5 6 1 .2 9 5 6 0 .8 0 5 6 0 .7 0 5 6 0 .8 0 5 6 0 .5 0 5 5 9 .1 0 5 6 4 .0 0 5 6 3 .1 0 5 6 4 .1 0 5 6 0 .9 3 5 6 1 .2 0 5 6 0 .6 9 5 5 9 .4 5 5 5 8 .4 2 5 6 3 .8 5 5 6 3 .9 5 5 6 4 .2 1 5 6 8 .4 0 5 6 4 .9 2 5 6 7 .7 0 5 6 4 .9 3 5 6 9 .9 0 5 6 8 .5 4 CSS. ? e 5 5 7 .5 0 S 6 C .S S 5 6 0 .7 0 5 6 2 .1 0 5 6 1 .7 0 5 5 9 .8 0 5 5 8 .2 6 5 6 2 .3 6 5 6 1 .9 0 5 6 1 .9 7 5 6 1 .8 2 5 6 0 .7 0 5 6 0 .5 0 5 5 9 .8 8 5 5 8 .6 6 5 6 1 .0 0 5 6 0 .7 0 5 6 5 .3 0 5 6 2 .7 0 5 5 8 .8 2 5 6 1 .3 5 5 6 2 .4 4 5 6 2 .6 1 5 6 5 .0 0 5 6 2 .3 6 5 6 4 .6 0 5 6 1 .9 9 5 6 7 .7 0 5 6 5 .1 5 5 6 6 .6 0 5 6 7 .4 5 5 6 1 .7 0 5 6 2 .9 0 5 6 2 .4 2 5 6 2 .9 7 5 6 2 .8 0 5 6 3 .3 4 5 5 5 .3 0 5 5 6 .9 7 5 5 4 .3 0 5 5 5 .6 0 Residuai -0 .7 3 2 .4 3 1 .8 3 2 .4 7 -2 .4 0 0 .1 3 2 .4 1 -2 .5 6 0 .3 4 -0 .1 8 -3 .0 9 -0 .0 9 -0 .1 3 -0 .5 0 0.11 1 .0 5 0.68 0 .1 5 -0 .8 5 - 0.11 3 .4 8 2 .7 7 1 .3 6 -0.50 -0 .7 6 -1 .7 8 - 1.20 0 .1 3 - 0.12 0 .8 2 1 .8 4 2 .1 8 -0 .6 5 2.86 0 .0 9 2 .6 4 2 .6 1 2 .5 5 -0 .8 5 -0 .7 2 -0 .0 7 -0 .5 4 tl.6 7 -1 .3 0 ASH000377 E ID Q 90476 --- Summary Statistics For ntire Modal Number of Targets - 44 Residual Mean 0 .3 2 1 5 4 9 Residual Standard Dev. * 1 . 5 9 9 5 6 7 Residual Sum of Sguares 1 1 7 . 1 2 8 3 1 1 Absolute Residual Mean Minimum Residual Maximum Residual - 1 .2 6 6 0 2 8 " -3 .0 8 9 6 4 8 3 .4 8 0 3 8 3 Observed Range in Head Res. S t d . Dev ./Range " 1 5 .6 0 0 0 0 0 - 0 .1 0 2 5 3 6 ASH000378 E ID 090477 T A B L E 5.2 Groundwater M odel Sum m ary DuPont W ashington W orks Parkersburg, W st Virginia Sensitivity Anlayses Recharge + 66% Recharge - 66% Conductivity + 50% Conductivity - 50% C o n d u ctan ce+5% Conductance - 5% River Stage + 2 feet River Stage - 2 feet Pumping +15 % Pumping -15 % R e sid u a l Mean R e sid u a l Standard D e v ia tio n R e sid u a l Sum of Squares A bsolute R e sid u a l Mean M inim um R e sid u a l Maxim um R e sid u a l -3.1 1.7 556 3.1 2.7 1.9 480 3.0 -1.2 1.8 202 1.8 4.7 3.8 1658 5.1 -0.6 1.6 128 1.5 1.3 1.6 193 1.7 -1.9 .6 270 21 2.6 1.6 408 2.7 5.2 2.0 1358 5.2 -4.2 1.7 913 4.2 Residual = Observed H ead m inus Modeled Head residual = modeled heads too high + residual = modeled heads too low c -5.6 0.7 -2.1 5.6 -5.3 2.8 -2.3 14.5 -3.9 2.7 -2.2 4.4 -5.1 1 4 -1.0 5.6 0.0 8.3 -7.6 -0.3 C alib rated ' Recharge 0.0025 1 0.00375 Conductivity 200 300 250 375 900 1350 Conductance 13.1 13.76 2.3 2.42 1.2 1.26 River Stage 584 586 Pumping (total) 5563 6398 Note: Model units are in feet and days. 0.00165 100 125 450 12.45 2.19 1.14 582 4729 ASH000379 Page 1 of 1 Sensitivity xls E ID 090478 TABLE 6.1 BURNING GROUND SOIL ANALYTICAL RESULTS: 0 - 2 FEET SRCNAME AA06-SB01 AA07-SB01 AA07-SB02 AA08-SB01 AA08-SB02 B07-SB02 AB08-SB01 D epth From To 02 02 02 02 02 02 D ate 9/2/98 9/16/98 9/27/98 9/27/98 9/27/98 9/4/98 AB0B-SB02 0 AC06-SB03 0 AC06-SB04 0 AC06-SB05 0 AC07-SB02 0 AC07-SB03 0 AC07-SB04 0 AC08-SB01 0 C08-SB02 0 Y07-SB01 0 Z06-SB03 0 Z06-SB04 0 Z07-SB01 0 Maximum Concentration 2 2 2 2 2 2 2 2 2 2 2 2 2 9m m 8/31/98 9/1/98 919m 9/9/98 9/14/98 9/14/98 9/27/98 8/24/98 9122m 9/15/98 9/11/98 9/10/98 Industrial Soil SL <CR* 10"8: H Q * 1) Maximum Cone. E xceeds SL? C arbon T etrachloride ug/kg Qual PQL ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 NO 44000 No ND 270 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 c FC-143 ug/kg Qual Ul Ul 82 32 u u Ul u u 15 u 39 64 29 Ul 53 u Ul Ul Ul 82 120000 (1) No PQL 24 25 12 11 12 12 37 12 10 13 11 11 11 12 21 11 11 26 26 22 A rsenic m g/kg Qual 8 7.4 5.6 9.8 8.7 9.4 10.2 3.7 11.7 8 5.2 5.2 6.2 7.5 6.9 4.9 10.2 5.9 12.7 12.7 3.8 c Yes B ariu m m g/kg Qual 167 108 142 112 106 72 79 43 42 41 662 270 131 139 142 212 78 124 71 562.0 140000 No n Cadm ium m g/kg Qual PQL ND 2.3 0.59 J 2.6 0.67 J 2.2 1.04 J 2.2 1.99 J 2.3 1.2 J 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 0.89 J 2.3 ND 2.3 ND 2.2 2.0 1000 No n Lead m g/kg Qual 10.5 11.6 11.5 26 19.6 10.5 14.8 5.6 10.6 9.7 9.7 11.4 11.3 10.2 12.8 3 9.4 12.9 14 26.0 1000 No' (2) N ickel m g/kg Q ual 12.2 12.6 12.8 16.7 13.2 15.5 17.3 8.5 13.1 13.2 11.7 12.4 16.9 13.2 14.7 2 .6 14.4 13.9 17.3 17.3 41000 No J n Leg e n d : c = Carcinogen. CR = T arget cancer risk for carcinogenic effects. HQ = Target hazard quotient for noncancer effects. J = Estim ated concentration below the PQL. n = Noncarcinogen. 11 ND = Not D etected, i PQL Practical Q uantitation Limit. i Qual * Laboratory d ata qualifier (J. U. Ut) or Not D etected (ND) i SL = Screening Level. EPA Region III risk-based concentrations (RBCs) for industrial son. based bn 1 in 1 million (10 ) ex cess cancer risk and noncancer hazard quotient of 1. U Not detected. Ul Not detected. N otes; (1) Preliminary screening level: se e Table 6.6 and Section 6.4.2 (2) Conservative SL for lead in industrial soil: se e Section 6 4.1 \ I .d*. >i. h. 1 1 . ;xh m i l \ m Page 1 o f 1 E ID 0 9 0 4 7 9 08000H SV TAdi.E 6.2 BURNING GROUND SOIL ANALYTICAL RESULTS: 2 - 20 FEE f SRCNAME AA06-SB01 AA06-SB01 AA07-SB02 AA08-SB01 AB06-SB01 AB06-SB01 AB06-SB02 AB06-SB02 AB07-SB02 AB07-SB02 AB07-SB02 AB07-SB02 AB05-SB02 AC06-SB03 AC05-SB03 AC06-SB04 AC06-SB04 AC06-SB05 AC06-SB05 AC07-SB02 AC07-SB03 AC07-SB03 AC07-SB03 AC07-SB04 AC07-SB04 AC07-SB04 AC07-SB04 AC08-SB01 AC08-SB01 AC06-SB01 AC08-SB01 AC08-SB02 AC08-SB02 D epth -rom TO 68 14 16 20 22 46 46 46 10 12 18 20 24 10 12 18 20 46 10 12 14 16 20 22 46 68 12 14 68 14 16 68 12 - 14 18 20 18 20 46 8 10 14 16 20 22 46 10 12 14 16 20 22 46 8 10 14 16 20 22 10 12 20 22 D ate 912m 912m 9/2/98 9127m 9/27/98 9/1/98 9/1/98 9/1/98 9/8/98 9/8/98 9/8/98 914m 9/4/98 9/4/98 9/4/98 9/27/98 8/31/98 8/31/98 9/1/98 9/1/98 919m 9/9/98 9/9/98 919m 9/14/98 9/14/98 9/14/98 9/14/98 9/14/98 9/14/98 9/14/98 9/14/98 9/27/98 9/27/98 9/27/98 9/27/98 8/24/98 8/24/98 C arbon Tetrachloride ug/kg Qual POL ND 240 ND 240 ND 240 NO 240 ND 240 ND 250 ND 260 ND 270 ND 230 ND 270 ND 240 330 260 840 250 230 J 390 NO 290 ND 250 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 ND 240 FC-143 ug/kg Qua) POL 140 14 51 12 U 11 91 12 U 12 Ul 24 Ul 22 Ul 21 U 12 17 11 U 11 U 12 36 13 59 12 U 11 11 10 55 12 12 12 63 12 Ul 22 U 12 U 11 U 11 U 12 U 12 Ul 23 18 13 U 11 U 13 13 11 U 12 U 12 Ul 35 m 25 u 11 Ul 23 u 12 u 10 A rsenic m g/kg Q ual 12.3 9.8 9 10.5 9.8 9.7 10.3 6.1 10.7 10.1 10.2 10 11.8 8.3 4.4 7 11.7 12 11.1 8.5 10.5 8 5.9 13 11.4 8.8 7.8 6 10.9 3.5 5.9 B ariu m m g/kg Qual 52 26 28 59 116 43 35 23 48 37 35 42 55 36 30 150 44 63 55 44 46 38 21 56 76 43 45 39 90 63 48 Cadm ium m a/ka Q ual POL ND 2.3 ND 2.2 ND 2.1 0.75 J 2.3 0.81 J 2.3 ND 2.3 ND 2.2 ND 2.1 ND 2.2 ND 2.2 M3 2.1 ND 2.3 ND 2.4 ND 2.3 ND 2 1 0.76 J 2.3 ND 2.4 ND 2.2 ND 2.4 ND 2.1 ND 2.3 ND 2.3 M3 2.1 ND 2.5 ND 2.5 ND 2.1 ND 2 3 ND 2.1 0.88 J 2.5 ND 2.4 0.23 J 2.1 Lead m a/ka Q ual 11.2 ' 7.2 6 11.9 14.9 9.5 7.4 6 9.1 6.9 4.8 10.3 9.7 7.9 4 .2 12.4 11.2 9.4 10.9 9.8 10.5 6 .6 5.4 13.1 6 .5 6.1 9.3 5.3 13.2 10 5.4 N ickel filia l 16.7 9.4 12.5 19 18.7 14.3 12.8 13.2 14.4 12.9 11.1 15.3 14.3 11.1 11.9 17.2 15.6 11.9 16.6 17.8 16.4 11.9 11.9 15.3 21.1 12.6 13 10.7 20.8 199 14.3 EID 090480 N I*** Nt 1. *K "* |lt 11 \ \( 18E 000H SV Page I of2 TABLE 6.2 BURNING GROUND SOIL ANALYTICAL RESULTS: 2 - 20 FEET SRCNAME D eath D ate From To Y07-SB01 4 6 9/22/98 Y07-SB01 B 10 9/22/98 Y07-SB01 14 16 9/22/98 Z06-SB02 2 4 9/22/98 Z06-SB02 Z06-SB02 8 10 9/22/98 14 16 9122m Z06-SB02 20 22 9/22/98 Z06-SB03 4 6 9/15/98 Z06-SB03 10 12 9/15/98 Z06-SB03 14 16 9/15/98 Z 06-S B 03 20 22 9/15/98 Z 06-S B 04 10 12 9/11/98 Z 06-S B 04 20 i i 9/11/98 Z07-SB01 10 12 9/10/98 Z07-SB01 20 22 9/10/98 Z09-SB01 2 4 9/3/98 Z09-SB01 8 10 9 1 3 m Z09-SB01 Z09-SB01 14 16 913190 20 ?? 913m Maximum C onosntration Industrial Soil SL (CR = TO-6. HQ = 1) Maximum Cone. E xceeds SL? C arbon T etrachloride ug/kg Qual PQL 180 J 240 ND 240 ND 240 ND 240 840 44000 No ND ND ND ND ND ND ND c 240 240 240 240 240 240 240 FC-143 ug/kg Qual U U 78 u 23 u *u Ul Ul Ul Ul 59 u Ul u 34 u u u 140 120000 (1) No PQL 11 13 11 12 13 10 12 21 22 21 21 13 11 24 10 12 12 12 11 A rsenic m g/kg Q ual 10.5 12.2 6.7 8.7 10 9 7 12.5 12 10.4 8.2 13 3.8 C Yes B ariu m m g/kg Q ual 46 71 50 45 44 43 27 65 59 65 41 150 140000 No n Cadm ium m g/kg Qual PQL 0.61 J 2.3 0.71 J 2.4 0.54 J 2.4 0.41 J 2.2 1) 2.3 ND 2.3 ND 2 ND 2.4 ND 2.5 1) 2.4 ND 2.2 0.88 1000 n NO 1ffTirl m afia Qual 8.9 12 8.4 7.4 11.7 7 .9 4.4 17 11.7 9.7 9.1 17 1000 No (2) N ickel m g/kg Q ual 13.3 14.2 12.5 15 13.7 10.5 17.2 19.8 16.3 14.7 21.1 41000 No n L egend: c s Carcinogen. CR 2 T arget cancer risk for carcinogenic effects. HQ * Target hazard quotient far noncancer effects. J * Estim ated concentration below the PQ L n * Noncarcinogen. ND > Not D etected. 1 PQL 2 Practical Quantitation U nit. Q ual Laboratory data qualifier (J, U, Ul) or Not D etected (ND). SL 2 Screening Level. EPA Region III risk-based concentrations (RBCs) fir industrial soil, based on 1 in 1 million (10*) - ! ex cess cancer risk and noncancer hazard quotient of 1. U 2 Not detected Ul * Not detected Notes.: (1) Prelim inary screening level, se e Table 6.6 and Section 6.4,2. (2) C onservative SL for lead in industrial soil; see Section 6.4 1. S 44tfcNm 12 II * IuM<> H - . 'l. J# 1 II AM Page 2 o f2 EID 090481 Z 8000H SV 1 E6J RIVER BANK LANDFILL/ ANAEROBIC DIGESTION PONDS SOIL ANALYTICAL RESULTS: 0 - 2 FEET SRCNAME D epth From To AA04-SB01 02 AA05-SB01 02 AC04-SB01 02 AE05-SB02 02 AF05-SB01 02 AH05-SB01 02 AI06-SB01 02 K04-SBQ1 02 L04-SB01 L06-SB01 02 02 M04-SB02 M04-SB03 02 02 M04-SB04 02 N04-SB01 N04-SB02 02 02 004-S B 02 02 0 0 4-S B 03 02 P04-SB02 02 Q04-SB03 02 R04-SB02 02 S04-Sk02 02 T04-SB01 0- 2 U04-SB01 02 V04-SB01 YO4-SB01 02 02 Maximum Concentration Industrial Soil SL (CR a 1 0 4 ; HQ = 1) Maximum cone, ex ceed s SL? Legend: D ate 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 10/11/98 10/10/98 9/30/98 9/29/98 8/20/98 FC-143 ug/kg Qual U Ul PQL 12 27 FREON 113 ug/kg Qual PQL ND 520 ND 510 22 40 14 35 55 81 79 34 32 50 170 9500 1100 60 140 600 22 9500 120000 No 11 ND Ul 22 ND 14 ND 12 ND 12 ND Ul 35 ND Ul 22 ND 12 ND Ul 24 ND 12 1600 J Ul 25 ND 13 ND 12 ND 11 ND 13 ND 13 ND 1300 ND 130 ND 11 170 J 13 ND 59 ND 14 ND 1600 (1) 6.1E+10 n No 530 530 590 500 520 440 470 500 530 470 560 780 600 480 530 630 560 650 600 560 610 540 M ethylene C hloride ug/kg Q ual PQL ND 260 ND 260 T etracN oroethene "9 * 0 Qua) PQL ND 260 ND 260 T rlcM oroetheae Q ual PQL 64 J 260 ND 260 ND 260 ND 260 ND 260 ND 270 510 270 ND 270 ND 300 ND 300 ND 300 ND 250 ND 250 160 J 250 ND 260 ND 260 ND 260 ND 220 ND 220 ND 220 ND 230 ND 230 ND 230 ND 250 ND 250 ND 250 ND 270 ND 270 HD 270 ND 240 ND 240 ND 240 ND 280 ND 280 ND 280 ND 390 ND 390 ND 390 ND 300 69 J 300 ND 300 ND 240 ND 240 1) 240 ND 270 ND 270 ND 270 ND 320 ND 3 ) ND 320 ND 280 ND 280 NO 280 ND 320 N SM Nb " W ND 300 ND 300 ND 300 ND 280 ND 280 ND 280 ND 300 ND 300 ND 300 ND 270 ND 270 ND 270 ND 510 1 ) 760000 c 110000 C 520000 c No No No CR -T a rg e t cancer risk for carcinogenic effects. ' HQ = Target hazard quotient for noncancer effects. J = Estim ated concentration below the PQL i n * Noncarcinogen ND * Not D etected PQL Practical Q uantitation Limit Qual 2 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 (10'*) ex cess cancer risk and noncancer hazard quotient of 1. U a Not detected Ul a Not detected N otes: (1) Preliminary screening level, see Table 6 6 and Section 6.4 2 (2) Conservative SL for lead in industrial soil; se e Section 6.4.1. S iwiUJtlttowTiniMahW- \ls HLi>OBAprHI 12AM Page I o f2 E ID 090482 8000H SV jE 6J RIVER BANK LANDFILL/ ANAEROBIC DIGESTION PONDS SOIL ANALYTICAL RESULTS: 0 - 2 FEET SRCNAME D epth From To AA04-SB01 02 AA05-SB01 02 AC04-SB01 02 AE05-SB02 02 A P rm .R R m 02 AH05-SB01 02 AI06-SB01 02 K04-SB01 02 L04-SB01 02 i n fi.R R m 02 M 04-SB 02 02 M 04-SB 03 02 M 04-SB 04 02 N04-SB01 02 u n a je n n o 02 0 0 4 -S B 0 2 02 004-SB03 02 P 04-S B 02 02 Q04-SB03 02 R rU -S R fl? 02 S 04-S B 02 02 T04-SB01 ' 02 U04-SB01 02 V04-SB01 v na.R R ni 02 02 Maximum Concentreition Industrial Soil SL (Cl * 2 10-6; HQ 2 1) Maximum cone, e x a aedsSL ?__________ D ate 8/20/98 9123190 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 10/11/98 10/10/98 9/30/98 9/29/98 8/20/98 A rsenic m g/kfl 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 Legend: CR = Target cancer risk for carcinogenic effects. HQ = Target hazard quotient for noncancer effects. J s Estim ated concentration below the PQL. n = Noncarcinogen. ND 2 Not D etected. PQL 2 Practical Quantitation Limit. Qdai Laboratory d ata qualifier (J. U, Ul) or Not Detected (ND) SL 2 Screening Level. EPA Region ill risk-based concentrati (RBCs) for industrial soil, based on 1 in 1 million (10*) ex cess cancer risk and noncancer hazard quotient of 1 U 2 Not detected. Ul 2 Not detected Notes; (1) Prelim inary screening level: see Table 6 6 and Section 6 4 2. (2) C onservative SL for lead in industrial soil: see Section 6.4 1 B arium m g/kg Qual 144 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 Cadm ium m g/kg Q ual PQL ND 2.4 0.51 J 2.3 ND 2.1 4.5 2.1 7.4 2.3 2.34 J 2.4 3.1 2 2 ND 2.2 0.7 J 2.3 0.91 J 2-3 ND 2.2 ND 2.4 0.36 J 2.4 0.3 J 2.3 ND 2.3 1 j 2.4 ND 2.2 ND 2.4 0.42 J 2.4 ND . 2.5 0.58 J 2.7 ND 2.4 3 2.2 3.3 2.3 ND 2.3 7.4 1000 n No Lead m o/kn Q ual 19 15.4 13.4 33 19 26 42 26 20.1 16.2 15.7 24.2 60 33 9.8 49 13.5 61 77 26 80 50 29 32 50 80 1000 (2) No N ickel m o/kg Q ual 20.8 17.1 13.8 12.1 20.1 19 18.1 26.2 20.8 14.1 188 32.6 32.1 22.2 14.7 34.0 12.8 36 4 1 .3 26.8 32.2 29 32.4 24.5 49.9 41000 No n s t < P H t <'* *1. It. t i * 1 14 12 AM Page 2 o f2 E ID 090483 weoooHsv SRCNAME AA04-SB01 AA04-SB01 AA05-SB01 AA05-SB01 AA05-SB01 AA05-SB01 AC04-SB01 AC04-SB01 AE05-SB02 AF05-SB01 AF05-SB0I AH05-SB01 AI06-SB01 K04-SB01 L04-SB01 L06-SB01 M04-SB02 M 04-SB02 M 04-SB03 M04-SB03 M04-SB04 M04-SBOS M04-SB05 M04-SB05 M06-SB02 M 06-SB02 M06-SB02 N04-SB01 N04-SB02 N04-SB02 N05-SB01 N05-SB01 N05-6B01 004-^802 004-b B 0 2 004-S B 03 0 0 4-S B 03 Dflpth From To 68 14 16 46 8 10 16 18 20 22 10 12 20 22 10 12 10 12 20 22 46 18 20 12 14 8 10 10 12 8 10 14 16 $8 14 16 10 12 24 68 12 14 24 8 10 20 22 12 14 8 10 14 16 24 8 10 20 22 68 14 16 10 12 14 16 1 . <jE 6.4 RIVER BANK LANDFILIVAEROBIC DIGESTION PONDS SOU. ANALYTICAL RESULTS: 2 - 2 0 FEET D ate 6120198 8120196 9/23/98 9/23/98 9/23/98 9/23/98 8/21/96 8/21/98 8/22/98 8/22/98 8/22/98 10/14/98 6123198 10/12/98 10/12/98 9125198 10/10/98 10/10/96 10/10/98 10/10/98 10/12/98 10/12/98 10/12/98 10/12/98 9128198 9128198 9129198 . 10/12/98 10/9/98 10/9/98 9128198 9128198 9/28/98 10/11/98 10/11/98 10/12/98 10/12/98 FC-143 ug/kg Qual 32 Ul 20 39 Ul 20 18 Ul U U U 34 U Ul Ul 280 Ul 26 u Ul 34 86 45 43 44 32 u Ul u 220 u 110 1800 Ul 28 u 24 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 ug/kg Qua! PQL ND 490 NO 570 ND 530 ND 630 ND 560 M ethylene C hloride ug/kg Qual PQL ND 240 ND 290 ND 260 ND 320 ND 280 T etn cN o ro ath m ug/kg Q ual PUL NO 240 ND 290 ND 260 1400 320 ND 280 340 340 1600 1600 1600 380 580 330 190 140 ND 650 ND 330 ND 480 ND 240 J 520 ND 260 1) 500 ND 250 580 ND 200 ND 500 ND 250 ND 530 ND 260 J 510 ND 260 J 490 ND 250 J 500 ND 250 ND 500 650 250 ND 500 320000 10000 ND 620 230 J 310 J 570 ND 280 ND 0 ND 280 510 ND 260 ND 550 ND 280 ND 500 ND 250 ND 500 ND 250 ND 570 730 290 ND 480 ND 240 J 530 ND 270 J 510 ND 250 ND 550 ND 280 ND 500 ND 250 J 520 ND 260 52 76 ND ND ND ND ND ND ND ND ND 1 ND ND ND ND ND ND ND ND NO J ND NO ND ND ND ND 3% 240 260 250 290 250 260 260 250 250 250 250 310 280 280 260 no 250 250 290 240 270 250 280 250 260 EID090484 4 2S IWR44i)Mw72 llV lahlls xK'li> >l/ * W '| ) \ \ A M S8E000HSV Page 1of4 i r " ` 6.4 RIVER BANK LANDFILL/r^ROBIC DIGESTION PONDS SOII, ANALYTICAL RESULTS: 2 -20 FEET SRCNAME D epth From To P04-SB02 8 10 P 04-S B 02 P 0 5 -S B 0 2 14 16 24 Q04-SB03 R04-SB02 B 10 10 12 R04-SB02 18 20 S 04-S B 02 B 10 S 04 -S B 0 2 18 20 S05-SB02 24 S 05-S B 02 10 12 T04-SB01 10 12 T04-SB01 16 18 U04-SB01 46 U04-SB01 16 18 V04-SB01 46 V04-SB01 16 20 YO4-SB01 10 12 Y04-SB01 18 20 Maximum Industrial S o l S L fCF! 1041: HQ 1) Maximum cone. E xceeds SL? D ate 10/9/98 10/9/98 9/24/98 1Q/11/9B 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 9129m 8/20/98 8/20/98 FC-143 ug/kg Qual 11000 10000 20 48000 7900 11000 44000 11000 28 140 U 54 95 U 170 Ul Ul U 48000 1200)0 (1) No PQL 1300 1300 12 3800 1300 1300 3800 1300 11 13 12 13 12 13 13 27 24 13 FREON 113 ug/kg Qual PQL ND 590 ND 560 ND 510 ND 550 ND 540 ND 590 ND 500 ND 520 ND 480 ND 520 ND 600 ND 540 ND 540 ND 670 ND 500 ND 580 ND 560 1600 6.1E+10 No n M ethylene C hloride 9 * 8 -- Qual PQL ND 290 ND 280 ND 260 ND 280 ND 270 ND 290 ND 250 ND 260 ND 240 ND 260 ND 300 ND 270 ND 270 ND 330 ND 280 ND 290 ND 280 320000 760000 No c T etracM oroethene uuai rU L ND 290 ND 280 1200 260 ND 280 ND 270 ND 290 ND 250 ND 260 ND 240 ND 260 ND 300 ND 270 ND 270 ND 330 ND 250 ND 290 ND 280 1400 110000 No c L tm n d : CR = T arget cancer risk for carcinogenic effects. HQ = T arget hazard quotient for noncancer effects. J = Estim ated concentration below the PQL. n Noncarcinogen. ND = Not D etected. PQL * Practical Quantitation Limit. Qual = Laboratory data qualifier (J, U, Ul) or Not Detected (ND). SL c Screening Level. ERA Region III risk-based concentrations (RBCs) for Industrial soN, based on 1 1n 1 million (10*) ex cess cancer risk and noncancer hazard quotient of 1. U h Not detected. Ul f Not detected. (1) Prelim inary screening level; se e Table 6.6 and Section 6.4.2 (2) C onservative SL for lead in industrial soil; see Section 6.4.1. E ID 090485 S t<PPr44.KN>72 OVTaWiK-rK tf'-l'* S iw - l ti |1 AM ! 98C000HSV Page 2 of4 P 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 M 04-SB 02 M 04-SB 02 M 04-SB 03 M 04-SB 03 M 04-SB 04 M 04-SB 05 M 04-SB 05 M 04-SB0S M 06-SB 02 M 06-SB 02 M 06-SB 02 N04-SB01 N04-SB02 N 04-S B 02 N05-SB01 N05-SB01 N05-SB01 OO4-SB02 004-SB 02 004-SB03 004-SB03 I From 6 14 4 8 16 20 10 20 10 10 20 4 18 12 8 10 8 14 6 14 -10 2 6 12 2 8 20 12 8 14 2 8 20 6 14 10 14 To 8 16 6 10 18 22 12 22 12 12 22 6 20 14 10 12 10 16 8 16 12 4 8 14 4 10 22 14 10 16 4 10 22 8 16 12 16 T. 6.4 RIVER BANK LANDFILLMEROBIC DIGESTION PONDS SOIL ANALYTICAL RESULTS: 2 -2 0 FEET D ate 8/20/98 8/20/98 9/23/98 9/23/98 9/23/98 9123m 8/21/98 8/21/98 8/22/98 6122m 6122m 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 9129m 10/12/98 10/9/98 10/9/98 9m m 9126m 9126196 10/11/98 10/11/98 10/12/98 10/12/98 TrichloroetH ene 1 A rsenic ug/kg Quai POL tng/kg Q ual ND 240 6.7 ND 290 5.2 ND 260 7,9 2200 "320" 3.8 ND 280 7.4 B ariu m m g/kg Qual 157 106 C adm ium I m g/kg Q ual POL, ND 2.4 ND 2.5 27 0.23 J 2.2 22 0 21 J 2.1 155 ND 2.5 19 8.4 7 4.1 13.1 1400 8800 78 340 ND 330 ND 240 ND 260 ND 250 290 ND 250 ND 260 ND 260 ND 250 ND 250 ND 250 ND 250 ND 310 ND 280 ND 280 ND 260 ND 280 ND 250 ND 250 290 J 240 270 ND 250 ND 280 ND 250 ND 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 62 140 148 157 233 142 136 130 146 122 180 134 38 35 33 137 229 102 147 43 32 178 108 146 144 1.94 2.7 11.8 0.33 0.24 0.28 1.4 0.7 0.29 0.33 0.24 J ND ND ND ND ND ND ND J ND ND J J J NO ND ND J J J ND J ND ND 2.6 2 .2 2 .5 2 .5 2 .5 2 .5 2 .5 2 .4 2 .4 2 .3 2 .3 2 .5 2 .5 2.1 22 2.1 2.5 2 .5 2 .5 2.3 2.2 22 2 .4 2.5 2.5 2.4 91 13.7 17.4 15.9 114 18.6 12.3 14.2 15.7 14.8 19 17.5 14 6.4 8.7 4 .9 14.4 17.3 10.9 99 8 6.1 18.7 15.5 19.2 14.9 15.6 a9.77 7 20.3 44.6 16.8 23.3 22.4 2 2 .3 30.4 25.3 21.6 24.5 20.5 13.7 26.7 22.6 9.6 12 14.7 20.8 26.7 20.7 17 12.2 10.4 27.1 23.9 29.7 23.4 E ID 090486 S 72 'laMi*** t l - `hi 10 | AM I 8000H SV Page 3 of4 T E6.4 RIVER BANK LANDFILLMEROBIC DIGESTION PONDS SOIL ANALYTICAL RESULTS: 2 - 2 0 FEET SRCNAME D epth From To P04-SB02 8 10 P04-SB02 14 16 P O 5-SB 02 24 Q 04-S B 03 8 10 R04-SB02 10 12 R04-SB02 18 20 S 04-S B 02 8 10 S 04-S B 02 18 20 S05-SB02 24 S05-SB02 10 12 TO4-SB01 10 12 T04-SB01 16 18 U04-SB01 46 U04-SB01 16 18 V04-SB01 46 V04-SB01 18 20 YO4-SB01 10 12 Y04-SB01 18 20 Maximum Industrial Soil SL (CR > 10-6; HQ 1) Maximum cone. E xceeds SL? D ate 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 9/30/98 9/30/98 9/29/98 9/29/98 8/20/98 8/20/98 T ricM oroethene ug/kg Qual PQL ND 290 ND 280 ND 260 ND 280 ND 270 ND 290 ND 260 ND 260 ND 240 ND 260 ND 300 ND 270 ND 270 ND 330 ND 260 ND 290 ND 280 A rsenic m g/kg Qual 6.80 8.60 6 . ) 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 B arium m g/kg Qual 172 170 830 171 180 186 187 193 91 30 195 187 162 155 212 128 117 Cadm ium m g/kg Qual PCM. ND 2.6 ND 2.6 ND 2.5 ND 2.S ND 2.6 ND 2.4 ND 2.5 0.91 J 2.1 0.63 J 2.3 ND 2.5 ND 2.5 2.5 2.3 2.55 J 2.6 2.8 2.5 2.35 J 2.6 NO 2.4 8800 520000 No c 22 830 11 8 3.8 c 140000 n 1000 n Yes No No Leoend: CR = Target cancer risk for carcinogenic effects. HQ * Target hazard quotient for noncancer effects. J = Estim ated concentration below the PQL. n = Noncarcinogen. ND Not D etected. PQL = Practical Quantitation Limit. Qual * Laboratory d ata qualifier (J. U. Ul) or Not Detected (N SL = Screening Level EPA Region III risk-based concentrt (RBCs) for industrial soil, based on 1 in 1 million O ff6) ex cess cancer risk and noncancer hazard quotient of 1. U = Not d e le te d . Ul = Not defected. Notes; (1 ) Preliminary screening level; see Table 6.6 and Section 6 4 . (2) Conservative SL for lead in industrial soil: see Section 6.4.1 Lead m g/kg Q ual 22 17.5 7.8 18.1 16.1 15.6 18.7 16.4 6.7 7.7 17.9 13 18 14 16.2 14.4 10.1 N ickel m g/kg Q ual 27.7 28.2 23.5 25.1 27.7 27.4 27.4 21.8 12.4 30 27.2 2 4 .7 26.6 28.5 22.1 20 114 1000 No 44.6 (2) 41000 No n E ID 090487 I \ m N M t K i n lal.k.' Ni. i <.4 w: w i i i u am 88000HSV ' P g e 4 o f4 TABLE 6.5 PRODUCTION W ELL GROUNDWATER CONCENTRATIONS COMPARED TO MCLs OR OTHER SCREENING CR ITERIA SRCNAME D ate K16-PW01 K16-PW01 L17-PW01 1 17JMAJM AM07-PW01 * AM07-PW01 * V05-PW01 \zn*.pvunt L04-PW01 L04-PW01 11/18/98 2/9/99 11/18/98 2/9/99 11/18/98 2/7/99 11/18/98 2/7/99 11/18/98 2/7/99 MCL or O ther Criterion Maximum cone. E xceeds Criterion? A rsenic mg/L 0 0013 ND 0.0043 ND 0.01 ND 0.0025 0.0017 0.0068 0.0028 0.01 0.05 No Qual J J J J J J MCL PQL 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Barium Qual mg/L 0.15 0.14 0.13 0.13 0.0672 J 0.0743 J 0.0845 J 0.0848 J 0.16 0.14 0.16 2 MCL No PQL Cadm ium Q ual m g/L 0.1 ND 0.1 ND 0.1 ND 0.1 ND 0.1 ND 0.1 ND 0.1 ND 0.1 ND 0.1 ND 0.1 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 Qual m g/L ND NO 0.0022 J ND ND NO ND ND ND ND 0.0022 0.015 (1) No PQL 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 N ickel m g/L ND ND ND ND ND ND ND ND ND ND 0 .1 4 No Q ual PUL 0.05 0.05 0.05 D.uo 0.05 0.05 0.05 0.05 0.05 MCL SRCNAME D ate K16-PW01 K16-PW01 11/18/98 2/9/99 L17-PW01 1 17.DUUni 11/18/98 2/9/09 AM07-PWQ1 * 11/18/98 AM07-PW01 * 2/7/99 V05-PW01 viK jpuuni 11/18/98 2/7/99 L04-PW01 11/18/98 L04-PW01 2/7/99 Maximum Concentration MCL or O ther Criteiton Maximum cone Ex seeds Criterion? FC-143 uo/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 J5 5 J5 J5 MCL TCE ug/L ND ND 22 22 5 5 22 5 Yes Q ual PQL 5 5 5 5 5 J5 MCL _________ MeCI uo/L ND ND ND ND ND ND ND ND ND ND f No Qua) PQL Freon 113 Q ual POL 5 5 5 5 5 5 5 5 5 5 MCL m " ----------------------- ND ND 64 56 270 270 59000 No (3) 10 10 10 10 10 J =|Estim ated value below PQL. MCL = Federal maximum contam inant Level (or drinking water. ND - Not detected. PQL = Practical quantitation limit. Plant potable w ater supply (well 336). Observed concentrations did not exceed screening levels. (1) Federal action level for lead in tap water. (2) Preliminary screening level; se e Table 6.6 and Section 6.4 2. (3) R isk-based concentration for Freon 113 (1.1,2-trichloro-1,2.2-trifluoroethane) in tap w ater (USEPA Region III. 1899) S.l*HXK44dlNm'72VI'aWft. "AW**lu MAM Page I o fl EIDQ 90488 68000HSV TABLE 6.6 CALCULATION OF PRELIMINARY SCREENING LEVELS FOR FC-143 IN SOULAND DRINKING WATER CEGair (1) mg/ra3 0 .0 0 0 3 Inhalation Rate (2) m3/day 20 Allowable Daily Intake (3) mg/day 0 .0 0 6 Water Ingestion Rate (4) L/day 2 PSL water (6 ) mgfl. 0 .0 0 3 S o il Ingestion Rate (6) "W M SO Conversion Factor m 9 ^ 0 .. 1 .E + 0 6 PSL soil m mg/kg 120 Allowable Daily Intake = C E G alr x inhalation R ata PSL w ater Prelim inary S creening Level fo r drinking w ste r * A llow able Daily Intake / W ater Ingestion R ate PSL so il = Prelim inary S creen in g Level fo r industrial so il= A llow able Daily intak e x 10** m g/kg / Soil in g estio n R ate (1) CEG alr = Com m unity E xposure G uideline for a ir e x p o su res (H askell Laboratory, 1991). (2) USEPA R egion IH default residential inhalation rate (USEPA Region III, 1999). (3) Allowable Daily Intake = C E G air x Inhalation R ate. `' (4) USEPA R egion ill default residential groundw ater ingestion ra te (USEPA R egion ill, 1999). (5) PSL w ater * Allowable Daily Intake / W ater ingestion R ate. (6) USEPA default industrial soil ingestion ra te (USEPA region III, 1999). (7) PSL soil = Allowable Daily Intake x m g/kg / Soil Ingestion R ate. ASH000390 S I * 44d>-w": 0* Trtlot vii BM* * :* ** 1 4 AM Page I o f I E ID 090489 Taule 6.7 RISK-BASED SCREENING FOR SOIL C onstituent A rsenic Barium C adm ium Lead Nickel C arbon T etrachloride F C -143 Freon 113 M ethylene Chloride T etrachloroethylene T rich lo ro eth y len e M axim um D etected C o n cen tratio n , m g/kg BG BG RBL/ADP RBUADP 0 - 2 ft 2 - 2 0 ft 0 - 2 ft 2 -2 0 ft 12 7 13 15 22 562 150 972 830 2 0.88 7.4 11.8 26 17 80 114 17.3 22.6 46.3 44.6 ND (<0.24) 0.84 - - 0.082 0.14 9 .5 48 - - 1.6 1.6 - - ND (<0.3) 320 - - 0.51 1.4 - - 0.16 8.8 Industrial Soil S>. (1) Max > Soil m g/kg SL? 3.8 AliSW M Us 140000 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 not available. BG * Burning G round. RBUADP = Riverbank Landfill and A naerobic Digestion Ponds SL = Screening Level (1) Industrial soil SL = R isk-based concentration (RBC) for industrial soil. USEPA Region III 1999. (2) C onservative SL for lead in industrial soil; s e e Section 6.4.1. (3) Prelim inary screening level; se e Table 6.6 and Section 6.4.2. EID090490 i I S i oW ahtr* *bvf(.7W2WW<l M AM 16000HSV TABLE 6.8 h ealth -ba se d SCREENING FOR PRODUCTION WELL WATER C onstituent A rsenic C adm ium Nickel FC-143 U nite mg/L mo/L mg/L mo/L m g/L ug/L P otable W ater W ell (1) 0.01 0 .0 7 ND (<0.01) ND (0 .0 0 3 ) ND (<0.05) 1.9 P ro cees W ater W alla (2) S creening Level T n - 0.0068 0.05 MCL M ax>SL? No 0.18 2 MCL No ND (0 .0 1 ) 0.005 MCL No 00022 0.015 MCL No ND (0 .0 5 ) 0.14 MCL No 16.2 3 PSL P o tab le-N o P ro c e ss-Y e s (3) Tetrachloroethylene ug/L NO (<S) Trichloroethylene ug/L NO (<5) 5 22 5 MCL No 5 MCL Potable - No P rocess - Y es (4) M ethyene Chloride ug/L ND (<S) - Freon 113 8^-___ ND <<10) 270 Legend: MCL = Maximum Contam inant Level for drinking w ater. PSL = Preliminary Screening Level; se e Table 6.6 and Section 6.4.2. RBC = Risk-based concentration for tap w ater (USEPA Region III, 1999) - * Not analyzed ' 5 59000 MCL RBC No No N otes: (1) Well 336 (AM07-PW01) (2) P rocess W ater Wells. K16-PW01 K16-PW01 L17-PW01 L17-PW01 V05-PW01 V05-PW01 L04-PW01 L04-PWQ1 (3) Trichloroethylene exceeded the MCL in production well V05-PW01. (4) FC-143 exceeded the preliminary SL in production w ells K16-PW01, V05-PW01. and L04-PW 01. ASH000392 S *: 1*5 M* t-*6 : t IO AM Pauc I of E ID 090491 TABLE &9 RARE, THREATENED, AND ENDANGERED TERRESTRIAL SPECIES (1) ' Peregrine Falcon {Falcoperegrinus) Indiana bat (Afyotissodalis) Gray bat (M grisescens) Northern flying squirrel (Glaucomyssabrinusfiacus) Eastern cougar {Feltsconcolor) Cheat Mountian salamander (Plethodon nettingi) Flat-spired three-toothed land snail {Triodopsisplatysayoides) shale banen rockcress {Arabiaserotina) Running buffalo clover {Trifoliumstoloniferum) Harperella {Ptilimnium nodosum) ' Northeastern bulrush {Scirpus cmeistrochaetus) Virginia spiraea {Spiraeavirginiana) (1) Source: West Virginia Division o f Natural Resources. These species are listed by both the U. S. Fish and Wildlife and the West Virginia Natural Heritage Program. ' ASH000393 E ID 090492 TABLE 6.10 RISK EVALUATION RESULTS Do C onstituent Levels Pose Potential Concern? Exposure Medium __________ BG Soil PWI Soil RBL/ADP Soil Potable Water W ells (2) Process Water W ells (3) . SWMU Impacted Groundwater Soil 0 - 2 ft No No No Soil 2 - 20 ft No No No G roundwater 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 manufacturing 0[vratio;.a. lliere were no significant ecological resources or listed speues leentitied within the RFI study area. (2) Potable water well = Well 336 (AM07-PW01). (3) Process water wells - K16-PW01, L17-PW01, V05-PW01, LQ4-PW01. ASH000394 E ID 090493