Document G3xqOpyK9VeOqj6Q581ovBqn

AR226-2521 C-8 DATA SUMMARY REPORT CONSENT ORDER QWR-2001-019 DUPONT WASHINGTON WORKS FACILITY AND LOCAL, LETART AND DRY RUN LANDFILLS Date: February 2003 Project No.: 7423 18983753.00036 CORPORATE REMEDIATION GROUP An Allian6e between DuPont and URS Diamond Barley Mill Plaza, Building27 Wilmjngton, Delaware 19805 ASH021621 EID639853 0-8 Dala Summary Report Table of ContgntS TABLE OF CONTENTS Executive Summary....... ,.................--.....--............................,..,........""---...--...,.-- .----vhi 1.0 Introduction......,.,...,.-.,,,-,,.....-.---..-.-.--..-.........-..-.........--............""-.--""--""1 1.1 Document Organization .........,.,,,..,.,,.,,...................-.......--................. ....,..,.,.3 2.0 C-8 Analyses and Analytical Reporting.........,....,.......,,................-.....------.--..... 4 2.1 Independent Quality Assurance Review ,......,,..,,.,,.,,,,,,....,,.........,.,,...........- ....5 3.0 Washington Works Facility.....................-.......,..............,....,.....--............................. 7 3>1 Introduction..............,.........,....,........................................*...."......""."."-- .......7 3.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling................................ ..........................,,....................,...........-- ..,--.--..7 3.2.1 One-Mile Radius Sampling ............................................................ 7 3.2.2 Two-Mile Radius Sampling........................................................... 8 3.2.3 Ohio One-Mile Sampling .......,,,,,,..,,,,..,,.....,,.,,...,,,,,,..,,.............-....... 9 3.2.4 Ohio Two Mile Sampling .,,,,,,,,..--------................--.-- ............9 3.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data .......,,.,,...,,..,,...,,,,.,.,,-..,,-- --...--.........--.........................--.-- 10 3.3.1 Monitoring of C-8 in Groundwater and Surface Water..................... 10 3.3.2 Ohio River Water Quality.....................^.......,......,..........--......--12 3.3.3 Public Water SupplySampling....------.................................... 13 3.4 Task C: Plume Identification/Groundwater Assessment,,,,.,,.........,,,,..,,..,,.... 14 3.4.1 Installation ofNew Wells at the Washington Works Facility........... 14 3.4.2 Hydrogeologic Testing of New Wells at the Washington 3.4.3 3.4.4 3.4.5 3.4.6 Works Facility...................----.............-- .......................................14 Washington Works Groundwater Model Refinement ....,,...,,.,,,,....,.. 15 Surface-water Field Reconnaissance at the Washington Works Facility 15 ....,,,,.,,...,,..,,..,,............,,....,,,,,,......................--.................... C-8 Monitoring in Groundwater and Surface Water at the Washington Works Facility .--...,,...,,--....,,,,.......,,.,,.......,,.,,.......... 15 Washington Works Facility Site Conceptual Model RejBneinent.,..........................-.........,................--....,.......----..........16 3.5 Revised Site Conceptual Model........,..........,,,.,,.......,.,....----....--.--.......... 16 3.5.1 Current Environmental Setting...................................--.................... 16 3.5.2 Current Human Health and Bcological Exposure Pathways............. 21 3.6 WashingtonWorks Facility Summary,...........,,.....,--.----...;..----................. 24 4.0 Local Landffll...................................;.........,...................,....................,........,...........26 4.1 Introducnon..........--.......,......--...,.....,...,.,............,...,..,.,.,........,.....,,...,..,.....--26 4.2 Task A: Groundwater Well and Water.Use Surveying and C-8 Sampung.....,.......................,..,....,..,-..................,...........,.......................----...26 4.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data..........................;.--..........................--............................27 WWK-C-8Data Wilmington. DE Summary- text final Feb. 5 , 0 3 ' " " " " " " T ASH021622 EID639854 C-B Dala SinTimary Report Table of Contents 4.3.1 Monitoring ofC-8 in Groundwater and Surface Water.............*,,..,.. 27 4.4 Task C: Plume Identification/Groundwater Assessment..,,.........------........ 28 4.4.1 C-8 Monitoring in Groundwater and Surface Water at Local 4.4.2 Landfill.......................-..,..,.....................-..-.......,......,-..................28 Surface-water Field Reconnaissance at the Washington Works Facility................-.......-.......................................,.............-.....----29 4.4.3 Installation ofNew Wells at Local Landfill ....,.......,,,...........-.--..29 4.4.4 Local Landfill Sits Conceptual Model Refinement..........,.,....,........^ 4.5 Revised Site Conceptual Model,..,,.............,,..................----..--..........,,.,,. 29 4.5.1 Current Environmental Setting.......................................................... 29 4.5.2 Current Human Health and Ecological Exposure Pathways............. 34 4.6 Local Landfill Summary ............,,-,,-......-- ..,,....--...........................................36 5.0 Letart Landfill..........................,,..,......................................,..........--------..--... 37 5.1 Introduction.........................,..,......................----"...--..------"------------"..37 5.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling...................................,,.................,,,,.....,,,,,,........................--........37 5.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data ..--........,.--.--............,,................----,,......,,....,.......------ 38 5.3.1 Monitoring of C-8 in Groundwater and Surface Water at Letart Landfill........................................................................... 38 5.4 Task C: Plume Identification/Groundwater Assessment.............................. 40 5.4.1 C-8 Monitoring in Groundwater and Surface Water at Letart 5.4.2 Landfill......................................................----.,,.......-...............-. 40 Surface-water Field Reconnaissance at the Letart Landfill,.............. 40 5.4.3 Installation ofNew Wells at Letart Landfill......-.---- .-........-..-.40 5.4.4 Letart Landfill Site Conceptual Model Refinement.......................... 41 5.4.5 Ohio River Water Sampling Near Letart Landfill ..----.........,,.,,.,, 41 5.5 Revised Site Conceptual Model...................................................................... 41 5.5.1 Current Environmental Setting............--......................................... 41 5.5.2 Current Human Health and Ecological Exposure Pathways ............ 46 5.6 Letart Landfill Summary,,.,,.,,....,......,,..,,,,......,,...,....----.............------..-- 48 6.0 Dry Run Landfill.............................................................................................. 50 6.1 Introduction.,..,........,...........--...--.........,.................................................--.....50 6.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling...........----................,,.,,.,,..,,.....,,,,......,,,,,,..........,,.,,,,,,.,,,,......,----.50 6.3 Task B: Assessment of Existing Groundwater and Surface-water Monitorimg Data.......................-..,,..--.........--..........-- ----........................51 6,3.1 Monitoring of C-8 in Gromidwater and Surface Water at Dry Run Landfill......------.-..-..------...............----.,,......,.........,.,,. 51 6.4 Task C: Plume Identification/Groundwater Assessment ..,,,,,,...,...,,,,.....,,.>.... 53 6.4.1 C-8 Monitoring in Groundwater and Surface Water at Dry 6.4.2 6.4.3 6.4.4 RunLandfill....,................,.......,.......,.,.,............,..,.........-.--.........-53 Surface-water Field Reconnaissance at the Dry Run Landfill........... 54 Installation ofNew Wells at Dry Run Landfill..-...------..----..... 54 Dry Run Site ConceptualModel Refinement...............----.............. 54 WWK-&0 Dala Summary - text final Feb. 5,03 11 WBmInfllon, DE ASH021623 EID639855 C-8 Data Summary Report Table of Contents 6.5 Revised Site Conceptual Model ............-................,...........--..--,--.- .54 6.5.1 Current Environmental Setting,.-...-................................ .54 6.5.2 Current Human Health and Ecological Exposure Pathways .57 6.6 Dry Run Landfill Summary...................,,,,,,,,...-...-.-....--.................. .59 7.0 References. .61 Table 3.0 Table 3.1 Table 3,2 Table 3.3 Table 3.4 Table 3.5 Table 3.6 Table 3.7 Table 3.8 Table 3.9 Table 3.10 Table 3.11 Table 3.12 Table 3.13 Table 3.14 TABLES Summary of Off-site Sampling Program (C-8 Sampling) - DuPont Washington Works Facility and Local Landfill Summary of C-8 Analytical Results in Ground-water and Surface Water (ug/1)- Washington Works Facility and Local Landfill (Off-Site Wells, Springs, and Cisterns - One-Mile Radius) Summary of Off-Site Sampling Program (C-8 Sampling)- Washington Works Facility and Local Landfill Two-Mile Radius Summary of C-8 Analytical Results in Groundwater and Surface Water (Off-Site Wells, Springs, and Cisterns) - Washington Works Facility and Local Landfill Two-Mile Radius). Summary of Off-Site Sampling Program (C-8 Sampling)- Ohio One-Mile Radius Residential Sampling Sunanaty of C-8 Analytical Results in Groundwater and Surface Water Ohio One-Mile Radius Residential Sampling Summary of Off-Site SamplingProgram (C-8 Sampling) - Ohio Two-Mile Radius Residential Sampling Summary of C-S Analytical Results Zones A, B, and C - Ohio Two-Mile Radius Residential Sampling Monitoring Well Construction and Groundwater Elevation Data - DuPont Washington Works Facility Summary of Analytical Results: C-8 in Groundwater - DuPont Washington Works Facility Summary of Analytical Results: C-8 m Surface Water - DuPont Washington Works Facility Ohio River Water SamplingC-8 Results - DuPont Washington Works and Letart Landfill Outfall 005 C-8 Concentration (ug/1)- DuPont Washington Works Summary of C-8 in Groundwater - Public Water Supplies, West Virginia and Ohio - DuPont WashingtonWorks SynopticGroundwater Elevations, February 2002, and Well Screen Locations - DuPont Washington Works Facility WWIW-8 Data Swnrnairy - tsxt tinal Feb. 5.03 lit WildftlBton, DE ASH021624 B1C639856 .--\ C-8 Data Summary Report Table of Contents Table 3.15 Table 4.0 Table 4.1 Table 4,2 . Table 4.3 Table 5.0 Table 5.1 Table 5.2 Table 5.3 Table 5.4 Table 5.5 Table 6.0 Table 6.1 Table 6.2 Table 6,3 Table 6.4 Table 6.5 Summary of On-Site and Off-Site Exposure Pathways Evaluation DuPont Washington Works Facility Monitoring Well Construction and Groundwater Elevation Data - Local Landfill Summary of Analytical Results: C-8 in Groundwater - Local Landfill Summary of Analytical Results: C*8 in Surface Water -Local Landfill Summary of On-Site and Off-Site Exposure Pathways Evaluation - Local Landfill Sunnnary of Off-Site SamplingProgram (C-8 Sampling) - Letart Landfill Summary of C-8 Analytical Results in Groundwater (ug/1)- Letart Landfill (Off-Site Wells- One-Mile Radius) Monitoring Well Construction and Groundwater Elevation Data - Letart Landfill Summary of Analytical Results: C-8 in Groundwater - Letart Landfill Summai'y of Analytical Results: C-8 in Surface Water - Letart Landfill Summary of On-Site and Off-Site Exposure Pathways Evaluation - Letart Landfill Summary of Off-Site Sampling Program (C-8 Sampling) Dry Run Landfill Summary ofC-8 Analytical Results in Groundwater and Surface Water (ug/1)- Dry Run Landfill (Off-Site Wells, Springs, and Cisterns - OneMile Radius) Monitoring Well Construction and Groundwater Elevation Data - Dry Run Landfill Summary of Analytical Resulte: C-8 in Groundwater - Dry Run Landfill Summary of Analytical Results: C-8 in Surface Water and Leachate - Dry Run Landfill Summary of On-Site and Off-Site Exposure Pathways Evaluation - Dry Run Landfill Figure 1.0 Figure 3.0 Figure 3.1 Figure 32 RGUHES DuPont Washington Works Properties Site Location Map - DuPont Washington Works Facility, Washington, WV One- and Two-Mile Radius Map - Local Landfill, Washington, WV One- and Two-Mile Radius ~ Summary of C-8 Results - Washington County, OH WWK-C-8 Data Summary - tBxt final Feb. 5,03 tv Wihiington, OB. ASH02KS25 BID639857 ^|P^ j& ^^ C.8 Date Summary of Contents Report___________________________________Table Figure 3.3 Figure 3.4 Figure 3.5 Figure 3.6 Figure 3.7 Figure 3.8 Figure 3.9 Figure 3.10 Figure 3.11 Figure 3.12 Figure 3.13 Figure 3.14 Figure 3.15 Figure 3.16 Figure 3.17 Figure 3.18 Figure 4.0 Figure 4.1 Figure 4.2 Figure 4,3 Figure 4,4 Monitoring Well and Surface Water Sample Location Map - DuPont Washington Works Facility, Washington, WV C-8 in Groundwate)--4Q02-DuPont Washington Works Facility, Washington, WV Ohio River Water Sampling Locations - Upstream - DuPont Washington Works Facility, Washington. WV Ohio River Water Sampling Locations - Downstream - DuPont WashingtonWorks Facility, Washington, WV C-8 Concentrations (ug/1)in the Ohio River and Public Water Supplies DuPont Washington Works Facility, Ohio - West Virginia Idealized Ohio River Valley Cross-Section and Block Diagram - DuPont Washington Works Facility, Washington, WV Generalized Geologic Cross-Section at River Mile 190 - DuPont Washington Works Facility, Washington, WV Cross-Section Location Map - DuPont WashingtonWorks Main Plant, Washington, W V Cross-Section A-A1 - DuPont Washington Works Main Plant, Washington, WV Cross-Section B-B' - DuPont Washington Works Main Plant, Washington, WV Cross-Section C-C' - DuPont Washington Works Main Plant, Washington, WV Cross-Section D-D' DuPont Washington Works Main Plant, Washington, WV Cross-Section E-E' - DuPont Washington Works Main Plant, Washington, WV . Cross-Section P-P' - DuPont Washington Works Main Plant, Washington, WV Cross-Section G-G' - DuPont Washington Works Main Plant, Washington, WV Revised - February 2002 Groundwater Elevation Map - DuPont Washington Works Main Plant, Washington, WV Site Location Map-Local Landfill, Washington, WV Local Landfill Monitoriag Well and Surface Water Sample Location Map - Local Landfill, Washington, WV Cross-Section Location Map - Local Landfill, Washington, WV Geological Cross-Section A-A' - Local Landfill, Washington, WV Geological Cross-Section B-B' - Local Landfill, Washington, WV WWK-C-B Data Summary- text Bnal Peb.5,03 V Wihninglon, DE ASH021626 EID639858 C-8 Data Surmnory B6pon Table of Contents Figure 4.5 Figure 4.6 Figure 4.7 Figure 5.0 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 5.10 Figure 5.11 Figure 6.0 Figure 6.1 Figure 6.2 Figure 6.3 Figure 6.4 Figure 6.5 Figure 6.6 Figure 6.7 Figure 6.8 Figure 6.9 Geolo^cal Cross-Section C-C" - Local Landfill, Washington, WV A-Zone Groundwater Elevation Contour Map - 4Q02 - Local Landfill, Washington, WV C-Zone Groundwater Elevation Contour Map - 4Q02 - Local Landfill, Washington, WV Site Location Map -Letart Landfill, Letart, WV . , C-8 in Groundwater - Letart Landfill, Letart, WV Monitoring Well and Surface Water Location Sample Map - Letart Landfill, Letart, WV Rt. 33 Stream and Brinker's Run Surface Water Sampling Locations Letart Landfill, Letart, WV Ohio River Water Sampling Locations - Letart Landfill, Letart, WV Cross-Section Location Map - Letart Landfill, Letart, WV Cross-Section A-A' - Letart Landfill, Letart, WV Cross-Section B-B' - Letart Landfill, Letart, WV Geologic Cross-Section C-C' - Letart Landfill, Letart, WV Geologic Cross-Section D-D' - Letart Landfill, Letart, WV D/E-Zone Oroundwaier Contour Map - 4Q02 - Letart Landfill, Letart, WV F-Zone Groundwater Contour Map - 4Q02 - Letart Landfill, Letart, WV Site Location Map - Dry Run Landfill, Lubeck, WV C-8 in Groundwater - Dry Run Landfill, Lubeck, WV Monitoring Well and Surface Water Location Map Dry Run Landfill, Wood County, WV Cross-Section Location Map- Dry Run Landfill, Wood County, WV Geological Cross-Section A-A' - Dry Run Landfill, Lubeck, WV Cross-Section B-B' - Dry Run Landfill, Lubeck, WV Geological Cross-Section A-C - Dry Run Landfill, Lubeck, WV Geological Cross-Section D-B*- Dry Run Landfill, Lubeck, WV A-Zone Groundwater Elevation Contour Map - 4Q02 - Dry Run Landfill, Wood County, WV B-Zone Groundwater Elevation Contour Map " 4Q02" Dry Run Landfill, Wood County, WV TOMK-C-aDalaSummaiy-tBttflnal Feb. 5,03 Wilmington, DE yl ASH021627 EID63985& C-8 Data Summary Of Contents Report____________.______________________Table Appendix A Appendix B Appendix C Appendix D APPENDICES Boring Logs and Well Construction Diagrams - Washington Works Facility Boring Logs and Well Construction Diagrams - Local Landfill Boring Logs and Well Construction Diagrams - Lctart Landfill Boring Logs and Well Construction Diagrams-Dry Run Landfill WWK-Ofl Date Summary -text final Fab. s, 03 Waminglon, DE vil ASB021628 EID639860 C.8 Data Summanf Report Summary _________________EXeCUttve EXECUTIVE SUMMARY A multi-media consent order (Order No. GWR-2001-019; Consent Order) was entered into between the West Virginia Department of Environmental Protection (WVDBP), the West Virginia Department of Health and Human Resources - Bureau for Public Health (WVDHHR-BPH) and DuPont on November 15,2001. The Consent Order identified a series of requirementsand tasks to be performedby the parties(WVDBP, WVDHHRBPH, and DuPont) in order to deteraaine whether there has been an impact on human health and the environment as a result of releases of ammonium perfluorooctanoate (C-8), CAS Number 3825.26-1, from DuPont operationsat the WashingtonWorks facility (facility, also referred to as the "maw, plant") and the associated landfills (Local, Letart, and Dry Run). The Consent Order established the C-8 Groundwater Investigation SteeringTeam (GIST) to oversee investigations and activities of the Consent Order including Task A: Groundwater Use and Well Swvey/Groundwater Monitoring. Task B: Assessment of Existing Groundwater and Surface Water Monitoring Data, and Task C: Plume Identincation/Groundwater Assessment at each site. The Consent Order also established the C-8 Assessment ofToxicity Team (CATT), which consisted of scientists from . academia, government, non-profit organizations, and industry, to assess the toxicity and risk to human health and the environment associated with exposure to C-8 releases from DuPont activities. This C-8 data summary report documents all activities conducted to meet the requirements of the Consent Order. In addition, the revised site conceptual models are presented, which better represent the current environmental setting(geology, hydrology, hydrogeology, groundwater flow, and water quality) and current human health and ecological exposure pathways for the conditions at and near the sites. The table below shows the results of the exposure pathways evaluation. This evaluation assessed whether human and ecological receptors were exposed to C-8 impactedmedia (e.g., soils, surface water, groundwater) bom on-site and off-site on the basis of data collected under the Consent Order. Pathways were classified as complete or incomplete. To be conservative, the highestC-8 concentration measured for each type of aqueous media was compared to the CATT-established human health protective screening criteria for water (C-8 SL) of 150 ug/1, regardless of media type. Note, however, (hat the CATTestablished Aquatic Life Advisory Concentration for C-8 (C-8 ALAC) of 1,360 ug/1is a more appropriatebenchmark for evaluation provided that waters are not ingestedsuch as surface water, groundwater, process water, and leachate. In this table, highlightedboxes indicate media that exceed the C-8 SL. This table shows that for all on-site and off-site media evaluated for the facility and the three landfills, only leachate and surface water at Letart Landfill exceed the C-8 SL. If these media were compared to the established C-8 ALAC of 1,360 ug/1, only leachate at Letart exceeds the C-8 SL. Most importantly, this table shows that all drinking-water sources are substantially below C-8 SL. WWK-C4 Data Summaly - text flnal Fob. 5,03 Wilrningtwi, DE vill ASH021629 SIt>63&861 C-8 Date Summary Report Executive Summary c-a impacted Media SWMUs/LBndtlled Materials 01 Soil Surface Water Groundwater 1 Drinking water ((romgroundwater) Process water (ftom groundwaler) DrinkingWater (welle, springs and/or cistern?)-WV S NorKlnnking water (vwlls. springs and/or cisterns)-WV s Unused water sources - WW r DrinkingWater (wells, springs i 0 and/or cisterns) * OH. Non-drinkingwater (wells, springs antyor cisterns) - OH Unused water sources OH Ohte Rhw water PW8 (WV and OR) Exposure pathway Aflgesame-nt (Complete (c) or incomplete (1)] Human Receptors Ecological Receptors I 1 1 1 1 1 1 1 C[1.9(L)ug/I] NA C (51.2 ug/1) NA C(2.8ugfl) 0(2.8 ug/l) 0(5.07 ug/1) i C(5.07jig/l) 1 C18.69U8/1) C(23.6ugfl) 1 C(1.09ufl/l) C (A6 ug/l) 0(8.59 ug/l) "" c@a$ua/i) """"'""I . C(1.09ug/l) C(4.20ug/l) SWMUs/Land!illed Materials Soil M Leachate 0 5 s Surface Water Qroundwater DrinkingWater (wells, springs 3 .. and/or cisterns). WV Non-drtrAIngwater (wells, springs andter cisterns)-WV Unused water sources - Local SYVMUs/Landfitled Materials So Leachate 0 SurfacB Water 3 aiwndwater DrinkingWater wells - Letart N&n^ifnklngwater welte- Letart 8 Ohio Rlw water Unused water eoweaa - Letart SWMUs/LandBlled Materials ^soli LeBchate (capturedand treated) Surface Water 5 Grcmndwater &inl(lna Wrter (weBs, springs ^ a ancVor dstems) - Diy Run Non-drinktofl water (wells, springs andtor cisterns) - Dy Run Dnused water Bciurces Diy Run I 1 0 ?180ugft) 0(115ug/l) i C (2.8 iig/l) C (5.07 ug/1) 1 | i 0(2050 ug/1) C (371 ug/l) 1 0 (0.139 ug/l) OINQ(<0.06)] 0(0.128ugll) 1 C (Unknown) C(Unknown) i c(Wua/ir """1 '.( C(0.422 ug/l) C (0.54 ug/l) ' I 1 C(120Ugfl) C (115 ug/l) I C(8.au8/l) C(@.07ugfl) I 1 1 C (2060 ug/l) C (371 ug/l) 1 0(0.139 ug/l) CINQ(<0.06)] CJ0.128ug/l) 1 0 (Unknown) G [Unknown) 1 C (87 ug/l) 1 C (0.422 U8/1) 0(0.54 ug/l) 1 (L) a biased low NA= not applicable Highlightedcells hdtoate eweedence or CATT-establtetied 08 SL (160 ug/l) WWK-C-8 Data Sunnnaiy- tsxtflnal Feb. 5,03 Ix Wilmington. DE ASH021630 EID63&862 c-a paia suwraiv Report______________________Executive Summary For the Washington Works facility^ the current revised site conceptual model combined with the current revised groundwater model, the current on-site and off-site C-8 concentrations measured, and the current exposure pathways evaluation show that: Q Solid Waste Management I Jnits (SWMUs) on-site are believed to be the primary source of C-8 migration to groundwater. Air depositionof C-8 on the ground surface and migration to groundwater also may have occurred. 0 No off-site migration of groundwater is occurring. Q No potential groundwater migration pathway exists beneath the Ohio River. Airemissions are believed to be the primary migration pathway of C-8 from the facility to adjacent areas in Ohio. 0 Air emissions of C-8 from the facility also are believed to be the source of C-8 cdncerifrations'oetecteffTri West Virginia adJicenftothe'faciHfy'andXbcal Landfill. ^ 3 Q Air emissions of C-8 and discharge of C-8 through outfalls are believed to be the ' migration pathways of C-8 from the facility to the Ohio River, and in turn, from the river to public water supplies (PWS) located downstream. Q There are no known complete exposure pathways for human or ecological receptors that exceed the CATT-established C-8 SL or the C-8 ALAC at the . facility. For the Local Landfill, the current revised site conceptual model combined with the current on-site and off-site C-8 concentrations measured and the current exposure pathways evaluation show that: Q C-8 is believed to migrate via water transport from C-8 containing landfilled materials to groundwater at the Local Landfill. Q Oroundwater flow from Local Landfill flows toward the facility to the northwest (away from off-site residential areas), Q C-8 detected in the one- and two-mile radius sampling areas near the facility and Local Landfill is likely to have been transported Ihmi the facility via air emissions. Q There are no known complete exposure pathways for human or ecological receptors that exceed the C-8 SL or the established C-8 ALAC at the Local Landfill. ' For the Letart Landfill, the current revised site conceptual model combined with the current on-site and off-site C-8 concentrations measured and the current exposure pathways evaluation show that: 0 C-8 is believed to migrate via water transport from C-8 containing landfilled materials to groundwater at the Letart Landfill. Q Groundwater flow at Letart Landfill is toward the Ohio River and is away from off-site residential areas. WWK-0.8 Data SunmiBly - text final Feb. 5. 03 Wilmfngton, DE ASH021631 EID639863 OS Date Summary iteport__________________________________Executive Summary Q The annual C-8 loading from groundwater to the Ohio River indicates a very low C-8 concentration in (he river from the landfill, which is supported by the very low C-8 concentrations measured in the Ohio River, Q Air emission of C-8 is not a viable migration pathway because there are no air emissions at Letart Landfill. 0 Contact with surface water (Cap Rimoff location) and leachate at the toe of the Letart Landfill and in the wet-weather stream surface water that dischargesto the Ohio River are complete exposure pathways for human or ecological receptors that exceed the C-8 SL. However, exposure is limited because of the remote location of the landfill, the very steep terrain, and the wet-weather nature of the stream. In addition, fencing limits access to the area. Further, the use of health and safety plans, standard operating procedures^and personal protective equipment also limit exposure. For Dry Run Landfill, the current revised site conceptual model combined with the current on-site and off-site C-8 concentrations measured and the current exposure pathways evaluation show that: Q C-8 is believed to migrate via water transport from C-8 containing landfilled materials to groundwater at the Dry Run Landfill. Q Groundwater flow at the site is toward the west. C-8 concentrations measured within the one-mile radius sampling area show that no off-site migration of C-8 impacted groundwater has occurred. Q Dry Run Landfill is located within eight miles of the facility. Transport of C-8 via air emissions from the facility potentially could be the source of the very low concentrations of C-8 detected within the one-mile radius samplingarea. WWK-C-8 Date Swwnaty- text final Feb. 5.03 WIMih^ton, DE xi ASH021632 EID639864 C-8 Date Summary Report ____________________Introduction^ 1.0 INTRODUCTION Since the early 1950s, ammonium perfluorooclanoate (C-8) has been used by DuPont in its fluoropolymer-related manufacturing processes at the Washington Works facility (facility, also referred to as the "main plant"). Residues containingC-8 from these processes have been released to the air: discharged to the Ohio River; disposedof at the WashingtonWorks facility and/or at the DuPont Local, Letart, and Dry Run landfills; and otherwise shippedoff-site for destruction or disposal(see Figure 1,0). C-8 has been detected in varying concentrations in and around the Washington Works facility and the associated landfills (Local, Letart, and Dry Run), in private drinkingwells and in public water supplies(PWS) located in West Virginia and in Ohio. A multi-media consent order (Order No. GWR-2001-019; Consent Order) was entered into between the West Virginia Department of Environmental Protection (WVDEP), the West Virginia Department of Health and Human Resources - Bureau for Public Health (WVDHHR-BPH) and DuPont on November 15.2001. The Consent Order identified a series of requirements and tasks to be performed by the parties(WVDEP, WVDHHRBPH, and DuPont) in order to determine whether there has been an impact on human health and the environment as a result of releases of C-8, CAS Number 3825-26-1, from DuPont operations at the Washington Works facility and the associated landfills. The Consent Order established the C-8 Groundwater Investigation SteeringTeam (GIST) to oversee investigations and activities that were conducted to assess the presence and extent of C-8 in drinking water, groundwater, and surface water at and around the facility and the associated landfills, as described in Attachment A of the Consent Order. Pursuant to Attachment A of the Consent Order, three tasks were performed by DuPont and evaluated by the GIST, Tasks A, B, and C. Task A: Groundwater Use and Well Survey/Groundwater Monitoring involved evaluating C-8 in groundwater initially within a one-mile radius from the Washington Works facility and Hie three landfills by sampling water from wells, cisterns, and springs. Included with these sampling activities was the samplingof PWS located one mile upstream and ten miles downstream of the facility. The area of investigation was expanded based on results obtained. Twelve PWS located within a river reach extending 3.5 miles upstream and 53 miles downstream were sampled. Available results were included in the One-mile Radius Survey and C-8 Sampling Report and the Ohio River Public Water SupplySampling (DuPont, 2002a). Task A activities are re-summarized in this report. Task B; Assessment of Existing Groundwater and Surface Water Monitoring Data included compiling historical C-8 data, monitoring all wells at the landfills, and developing a Groundwater Monitoring Plan (GMP) for the Washington Works facility and the Local, Letart, and Dry Run Landfills. The historical C-8 data compilation report was submitted to the GIST for evaluation (DuPont, 2002b). The second part of Task B, monitoring C-8 in surface water and groimdwater at the landfills, began in December 2001. Sampling was performed monthly for four months and is now conducted quarterly. The Proposed GMP for the Washington Works facility (DuPont, 2002c) was submitted to the GIST for review and was approved following minor modifications (DuPont, 2002a). WWK-OO Date Swmnaty - text final Feb. S. 03 Wllrnlnaton. DE ASH021633 EID639865 C-B Data Summary Report __________________Introduction Groundwater sampling at the Washington Works facility pursuant to the approved GMP began in late January 2002. Task B activities also are re-summarized in this report. Task C: Plume IdentirScation/Groundwater Assessment at each she began following the completionof Tasks A and B. This activity included delineating the vertical and horizontal extent of C-8 impacted groundwater and specifically included an assessment ofC-8 impacted groundwater at the Letart Landfill and its impact on the Ohio River and PWS along the river as requiredby the Consent Order. The C-8 Plume Identification Groundwater Assessment Work Plan was submitted to the GIST in May 2002 (DuPont, 2002e). For the WashingtonWorks facility. Task C included groundwater modeling using GIST-approved groundwater modelingtools. Groundwater modeling was used to evaluate possibleC-8 migration pathwaysin groundwater from the facility. A separate groundwater modeling report was issued to the GIST in January 2003 (DuPont, 2003a). This report documents Task C activities and re-summarizes briefly the groundwater modeling results. While conductingthe activities identified in Tasks A, B, and C which were designed to assess the presence and extent of C-8 in drinking water, surface water, and groundwater, an evaluation of transport mechanisms for C-8 migration also was conducted. This evaluation was conducted to gain a better understanding of how C-8 migrates in the environment and to better understand the results generated during the implementation of Tasks A, B, and C. Two main possibletransport mechanisms were considered in evaluating results. These were air transport and water transport. Air transport was considered because DuPont had released, and continues to release, C-8 in air emissions from the facility. C-8 particles in air emission may have been depositedon surfaces of structures (roofs, etc.) and then have been dissolved and transported by precipitation into cisterns. C-8 in air emissions also may have been depositedon ground surfaces and dissolved and transported by precipitation to surface-water bodies or to groundwater, In addition, C-8 was detected at low concentrations in some of the water samples taken from cisterns. If the cistern was filled using a PWS that had been shown to contain C-8, then the source of the C*8 in the cistern may have been the water used to fill the cistern. Alternatively, the source of C-8 in the cistern may have been from air emissions. It also may have originated from both sources. Water transport, including transport via surface water and groundwater, was considered because C-8 bearing materials were disposedofon-site (i.e., facility and landfills) and C-8 had been detected m surface water and groundwater from various sources at and near the Washington Works facility and the three landfills. Sampling performed under Task A of the Consent Order resulted in detections of C-8 in the Little Hocking Water Association well field, which is the PWS located immediately across the Ohio River from the Washington Works facility. A formal groundwater modeling evaluation was performed to determine if imported groundwater from the facility migrated off.site toward Little Hocking. The Consent Order also established the C-8 Assessment ofToxicity Team (CATT). The CATT consisted of scientists from academia, government, non-profit organizations, and industry. The CATT was assembled to assess the toxicity and risk to human health and WWK-C-8 Date Summary - text final Feb. 5.03 Wllmlngton.DE A8H021634 E1D639866 C-6 Data Summary Report ...______._________________Introduction the environment associated with exposure to C-8 releases from the DuPont activities. In a final report issued in August 2002, the CATT established the human health protective screeningcriteria for water (C-B SL) of 150 ug/1(WVDEP, 2002). The results presented in this report which were obtained for Tasks A, B, and C, are compared conservatively to the CATT-established C-8 SL of150 ug/1, regardless ofwater use. In addition, as reflected in the August 2002 report, the CATT also established a C-8 screening criteria of 240 mg/kg for soils (WVDEP, 2002). However, development of a method for analyzing C-8 in soils has not yet been completed;therefore, no soil samples have been analyzed. The CATT also established an Aquatic Life Advisory Concentration for C-8 (C-8 ALAC) of 1360 ug/1in October 2002 (Menzie-Cura & Associates, 2002). Surface-water results presented in this report are compared to these screening criteria and to the C-8 SL 1.1 Document Organization Section 2 of this document providesinformation on C-8 reporting and data validation. The remainder of this report discusses specific activities conducted and results obtained at the facility and the Local, Letart and Dry Run Landfills. Section 3 presents the WashingtonWorks facility data. Sections 4,5, and 6, present data for the Local, Letart, and Dry Run Landfills, respectively. Within each section, a similar format is followed. A brief introduction is presented. The next three subsections then describe activities performed and results obtained for Tasks A, B, and C, respectively. The revised site conceptual model, which integrates the new results, is then discussed. A human health and ecological exposure assessment follows. Finally, observations for each site are summarized. Section 7 of the report provides a reference list, including Consent Order related documents previously submitted to the GIST. WWK-MDatgSumiriBiy-textlinat Feb. 5,03 Wilmington, DE A5H021635 BID6398$7 c.8 Date. summary Report ______ ___C-8 Analyses and Analytical Reporting 9 2.0 C-8 ANALYSES AND ANALYTICAL REPORTING The Quality Assurance Project Plan (QAPP; DuPont, 20021)discusses the procedures and protocols developed to ensure that project information, data, and decisions derived from or based on data acquired during the ground-water investigationat The facility and associated landfills are technically sound, usable, and properly documented. Specifically, Sections 5,6, and 10 of the QAPP present samplingprotocols, sample and document custody procedures, and internal quality control checks that were followed duringthe field sampling activities associated with the groundwater well and water-use survey. The QAPP also presents information on quality assurance, calibration procedures and .frequency, analytical procedures, data reduction, verification, and reporting. Information on the analytical method and the precision criteria used for the C-8 reporting are summarized below. Exygen Research. Inc. (Exygen), located in State College, Pennsylvania, originally developed and tested a new analytical method that utilizes Liquid Chromatography/TandemMass Spectrometry (LC/MS/MS). DuPont adoptedthis method (LC/MS/MS) for analyzing C-8 in water to November 2001. Currently, Exygen performs all C-8 water sample analyses for DuPont using the laboratory Standard OperatingProcedure (SOP) it developed. Exygen reports C-8 results for the laboratory replicateof each field sample. These results are evaluated for precision by comparing the field sampleresult to the corresponding laboratory replicate result: Q If both results are less than the practical quantitation limit (PQL), the replicate sample for that analyte is considered to have passedthe precision criteria. 0 If one or both results are between one and five times the PQL, the replicate is considered to have met the precision criteria if the two results differ by less than the PQL. Q If one result is less than the PQL and the other is not and if the two results differed by a value less than the PQL, the replicate is said to have met the acceptance criteria. Q Finally, if both results are at least five times the PQL, the replicate is considered to have met the criteria if the relative percent difference (RPD) between the two results is less than or equal to 20%. The RPD is the absolute value of the difference of two measurements divided by their average. When me precision criteria outlined above are met, Exygen reports the average of the field sample and the laboratory replicate results are reported. If criteria for precision are exceeded, Exygen reports the higher of the sample and laboratory replicate results. Finally, when one result (from the sample/laboratory replicate pair) is above the PQL and one below, the result that is above the PQL is reported. C-8 results are recorded in the Corporate Environmental Database (CED) and are reported as FC-143 for consistency with historical results. WWK-Ofl Data Summaly - text Bnal Feb. 5,03 Wllmington, DE ASH021636 EID639868 c-6 Data summary Report Analyses and Analytical Reporting _____C-8 An aliquot of each field sample also i$ analyzed as a matrix spike (MS). Results of the MS analysis are used to assess accuracy. The MS recovery value must fall between 70 to 130%, unless the sample concentration is at least four times the amount spiked. The maximum amount used to spike field samples is 500 ug/1. The QAPP Addendum (QAPP Addendum, DuPont, 2002g)was generated during May 2002 in order to document a reduction in the number of laboratory QC samples (matrix spike and replicate) to a frequency of5%i or one each per analytical batch (whichever is greater) for groundwater and surface-water samples collected within the facility and landfill boundaries. Specifically, analysis of well, outfall, and stream samplescollected at fhe facility. Local Landfill, Letart Landfill, and Dry Run Landfill were subsequently performed with fluereduced QC sample frequency. This reduction in QC sample frequency was made because a substantial database exists for these samples, including at least three rounds of sample analysisat Exygen. There was no reduction in QC sample frequency for samplescollected outside the facility and landfill boundaries, such as off- site wells, tap water samples, cisterns, PWS, and Ohio River water samples. ^ All data packages generated by Exygen have been reviewed in-house for compliance with the laboratory SOP and QAPP Addendum, and for data usability, using the checklist provided in fhe QAPP. Results of the m-house review indicate that data reported by Exygen have been generated in compliance with the laboratory SOP and QAPP Addendum with few exceptions, as noted in the individual review summaries and discussed below. All data reportedby Exygen have been judged usable for the purposes of fhe project. Exygen reported that seven of the Ohio two-mile radius samples (including two field blanks) from one data package, and two samples from Local Landfill, collected during November 2002 and reported in another data package, were analyzed beyond the sample hold time of 14 days (as per the SOP). These samples were analyzed within two times the specifiedhold tune. The laboratory also has reported that non-project, field spiked samplesat 100 and 1,000 ug/1, have exhibited stability for periods as long as one year (Bxygen, 2002). The data packages were examined in-house, using the review protocol included in the QAPP, and the results were determined to be usable for project purposes. All data reported by Exygen have been judged usable for the purposes of the project 2.1 Independent Quality Assurance Review A subset of the data packages generated by Exygen were submitted to Environmental Standards, me (ESI) in Valley Forge, Pennsylvania, for an independent (i.e., third-party) qualityassurance review. Thirty-eight data packages, containing results for 326 samples, includingfield blanks and duplicates, were submitted for validation. The samples submitted for review represent samples collected from the West Virginia one- and twomile radius, Ohio one-and two-mile radius, Ohio River sampling, aad PWS. The samples submitted for review represent 23.7% of the samples, collected between December 2001 and November 2002, from the West Virginia one- and two-mile radius, Ohio one-and two-mile radius, Ohio River sampling, PWS, and facility and landfill groundwater and surface-water sampling. Data packages/samples submitted for the independent quality assurance review were selected at random; however, off-site residential and PWS samples were preferentially selected because these samples were collected from drinking- WWK-08 Data Summaly-text final P(A.5.03 5 Wllinlngton, DE ASH021637 BIDg39869 c-apatesumma-yReport______________C-8 Analyses and Analytical Reporting water sources. In addition, samples of particular interest to the GIST, such as samples yielding positive analytical results from the Ohio River sampling were submitted for review. The quality assurance review was performed by ESI with guidance from the Region III Modifications to National Functional Guidelines for Organic Data Review [UnitedStates Bnvironmental Protection Agency (USEPA), 1994]. Data were examined by ESI to determine the usability of the analytical results and compliance relative to the QAPP, QAPP Addendum, and the laboratory SOP. Results of the quality assurance review indicated that the quality of the data is acceptable and qualification of the data was not warranted, with the exception that positive results for two samples reviewed were qualified J, as estimated, due to precision criteria between the sample and lab replicatenot being met. It should be noted that the laboratory, and DuPont, in this case and any similar cases for data not submitted for independentreview, reported the higher of the two results. WWK-C-B Data Summary - text final Peb. 5,03 Wllmingion, DE ASH021638 EID639870 w DBB summary Report Washington Works Facility 3.0 WASHINGTON WORKS FACILITY 3.1 Introduction The facility is located along the Ohio River in Washington, West Virginia, approximately seven miles southwest ofPaAersburg, West Virginia (see Figure 3.0). Consent Order required tests to be conducted at or immediatelyadjacentto the facility included the following: 0 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling-- conduct a distance-phased groundwater well and water-use survey identifying and samplingall groundwater wells>springs,and cisterns within a one-mile (and possiblytwo- and three- mile) radial distance of the facility and. the Local Landfill. 0 Task B: Assessment of Existing Groundwater and Surface Water Monitoring Data--develop and implement a monitoringplan that evaluates the presence and extent ofC-8 in drinking water, groundwater, and surface water in and around the facility and perform an assessment ofC-8 impact to the Ohio River and to PWS within one mile upstream and 10 miles downstream (and possiblytwo and three miles upstream and 20 and 30 miles downstream) of the facility. 0 Task C: Plume Identification/Oroundwater Assessment---detennine the vertical 08 and horizontal extent of impacted groundwater exceeding 1 ug/1 or as directed by the GIST, using groundwater modeling tools approved by the GIST if modeling is done. In Sections 3.2 through 3.4, discussions of the specific activities conducted to meet the requirements of the Consent Order are presented along with the new data acquired while conducting these activities, to Section 3.5, the revised site conceptual model updates the current environmental setting (geology- hydrology, hydrogeology, groundwater How, and water quality) and cunent human health and ecological exposure pathways for the conditions at and near me site. i- 3.2 Task A: Qroundwater Well and Water-Use Surveying and C"8 Sampling 3.2.1 One-Mile Radius Sampling The Local Landfill is located immediatelysouth of the facility. Because of the proximity of the Local Landfill to the facility, groundwater wells located within the combined onemile radius (of both sites) m West Virginia were sampled (see Figure 3.1). The groundwater well and water-use survey and sampling within the one-mile radius of the , facility and the Local Landfill were completed on February 12,2002. DuPont submitted the results of the one-mile radius survey to the GIST in April 2002 (DuPont, 2002a). WWK-C-fl Data Summary - text Bnal Feb. 3.03 WBmIngton.DE ASH02163& EID$3987l . \ .Ijijj^ 'i'^ c.e Datesumn^ Report__________________WashI!19tonw^rksFa^ Table 3.0 summarizes the off-site survey and sampling program for the one-mile radius. A total of 269 homes were surveyed, and a total of 44 water sources were sampled. Six wells used for drinking water were sampled. No cisterns or springssampledwere used for drinkingwater. Table 3.1 provides details for each sample collected, including the C-8 concentration measured (ug/1). Figure 3,1 shows the locations of all samples collected, regardlessof water use. Each colored circle represents a samplinglocation and the color and size of the circle indicate the magnitude of the C-8 concentration measured. For example!, small black circles represent sampleshaving C-8 concentrations ranging from to 1.0 to 10 ug/1,while large black circles represent samples having C-8 concentrations greater than 10.0 ug/t. Note that the number of C-8 detections above 10 ug/1are limited. Table 3.1 shows that the C-8 concentrations in six drinking-water samples during the one-mile radius sampling ranged from 0.328 to 2.8 ug/1. Because the drinking-water sampleshad C-8 concentrations above the 1 ug/1threshold level described by the Consent Order, the GIST ordered the expansion of the radius to two miles and resamplingthe drinking-water samples within the one-mile radius. The highest C-8 concentration in a non-drinking source was 5.07 ug/I, The highestC-8 concentration in unused water sources was 14.3 ug/1. C-8 concentrations measured in the six cisterns sampled ranged from 0.561 to 3.52 ug/1 (see Table 3.1). These results indicated that air transport of C-8 as a migration pathway was possibleif cisterns were filled by precipitation. If water is added to the cistern from another source (groundwater, PWS etc.) then water transport of C-8 is possible. Survey results from individual residents show that cisterns were filled predominantly by precipitation. 3.2.2 Two-Mile Radius Sampling The groundwater well and water-use survey and C-8 sampling within the two-roile radius of the facility and the Local Landfill were completed on June 3,2002. DuPont submitted the results of the two-mile radius survey to the GIST in August 2002 (DuPont, 2002h). Table 35 summarizes the off-site survey and sampling program for the two-mile radius. Within the two-mile radius a total of 109 homes were surveyed, and 65 water sources were sampled. Seventeen wells and one springused for drinking water were sampled. None of the eight cisterns sampled was used as a drinking-water source. Table 3.3 provides details for each sample collected, including the C-8 concentration measured (ug/1). Figure 3.1 includes (he C-8 results for the two-mile radius. All samples are posted regardlessofwater use. Of the 18 drinking-water samples, only one (a spring sample)had a C-8 concentration greater than 1.0 ug/1. The C-8 concentration in the springsample was 1.8 ug/1. All drinking-water samples from wells had C-8 concentrations less man 1.0 ug/1. The highest C-8 concentration measured in non-. drinking-water and unused water sources were 1.67 and 2.32 ug/1, respectively. C-8 concentration measured in the wells from the one-mile radius that were resampled ranged from 0.526 to 2.48 ug/1(see Table 3.1). WWK-C-B Date Sunimay-text final Feb. 5.03 Wllmlnaton. DE 8 ASH021640 BID63&8-72 Mpatesumm-.rytepm _____________Washington Works Facility ^ ^B Again C-8 concentrations measured in the eight cisterns indicated air transport as a possible C-8 migration pathway from the facility because the cisterns were predominantly filled via precipitation. The results for the two-mile radius showed a trend toward lower concentrations than were found in the one-mile radius sampling area. While the two-mile radius was being conducted, (he CATT released the human health protective screening criteria for water (C-8 SL) of 150 ug/1(WVDEP. 2002). In August 2002, the GIST determined that no further off-site surveying or resampling around the facility and the Local Landfill was ' needed. 3.2.3 Ohio One-Mile Sampling Off-site surveying and samplingalso was conducted in Ohio. C-8 was initially measured in the Little Hocking Water Association well field (a PWS sampling point), located in Ohio directly across the Ohio River from the facility in December 2001 (see Section 3.3.3). DuPont and the Ohio Environmental Protection Agency (OEPA) agreed that the groundwater well and water-use survey would be expanded to a distance one mile from the facility boundary into Ohio. The groundwater well and water-use survey and C-8 samplingwithin the one-mile radius in Ohio were completed on June 7,2002. DuPont submitted the results of the one-mile radius survey to the OEPA and the GIST in August. 2002 (DuPont, 2002i). Table 3.4 summarizes the one-mile radius survey and samplingin Ohio, The total number of homes surveyed was 150, and the total number of water sources sampled was 68. Of the 68 water sources sampled, 17 were from drinking-water wells, and one was from a drinking-water spring. No cisterns sampled were used for drinking water. Table 3.5 provides details on (he samples collected, including the measured C-8 concentration. The C-8 concentration measured for the drinking-water wells ranged from non-detectable [<0.01 ug/1(ND)] to 8.59. The C-8 concentration for a drinking-water springwas 13.9 ug/1. The highest C-8 concentration measured in non-drinking-water sources and unused sources was 23.6 and 16.9 ug/1, respectively. Figure 3.2 is a map showing the location of samples, regardless of water use, collected within the Ohio one-mile radius. This figure uses the same symbols a$ were used in Figure 3,1. Locations of samples having C-8 concentrations greater than 10.0 ug/1appearedto be clustered to the northeast and northwest. C-8 concentrations measured in the five cisterns ranged from 0.748 to 7.33 ug/1. These results indicated that air transport of C-8 was a possiblemigration pathway from the facility, providing the cisterns were filled by precipitation. Even thoughthe highestC-8 concentration measured for a drinking-water sample within the one-nrile radius was an order of magnitude lower that the CATT established C-8 SL of 150 ug/1,nine non-drinking-water and unused water source sampleshad C-8 concentrations above 10,0 ug/1. Based on these results, OEPA requested an expansion of the survey area to a two-mile radius. 3.2.4 Ohio Two Mile Sampling T h e groundwater well and water-use survey of the facility were completed on September and 30, C-8 sampling within the two-mile radius 2002. DuPont submitted the results of WWK-C-8 Data Sunimaiy.- text Snal Feb. 5.03 . Wthiington. OB 9 . ASH021643. EID639873 c-a Date summaryReport________________Washington Works Facility the two-mile radius survey to the OEPA and the GIST in December, 2002 (DuPont, 2002J). For the Ohio two-mile radius, the samplingstrategy was modified following discussions with the OEPA and the GIST. The two-mile radius survey area was divided into three areas, "A", "B", and "C"(see Figure 3.2). All homes within the entire area within the two-mile radius, areas "A", "B", and "C", were surveyed. In area "B" all identified wells, springs, and easterns were sampled, regardless of use (drinkingwater, lion-drinking water, or unused) because this portion of the two-mile radius was adjacentto an area within the one-mile radius where the highest C-8 concentrations were measured. In addition, all identified drinkingwater, non-drinking water, and unused wells, springs,and cisterns from residences located along Township Road 97 (located within area "C") were sampled. In area "A" and "C", wells, springs, and cisterns were sampled only if these sources were used for drinking-water, non-drinking-water aid unused sources were not sampled. Areas "A" and "C" are adjacent to areas in the one-mile radius where lower C-8 concentrations were measured. Table 3.6 provides a summary of the Ohio two-mile survey results, to total, 733 homes were surveyed, and 62 water sources were sampled, including49 wells used for drinking water. No cisterns or springssampled were used as drinking-water sources. Figure 3.2 also shows the location of samples, regardless of water use, collected within the Ohio two-mile radius. Table 3.7 provides details of the samples collected, including the measured C-8 concentrations. The C-8 concentrations measured in drinking-water samples ranged from ND to 6.5 ug/1, with only 11 sampleshaving C-8 concentration greater 1.0. ug/1. The highestC-8 concentration measured for the non-drinking-water samples ranged was 6.85 ug/1. The highestC-8 concentration measured in an unused source was 8.68 ug/1. The range of C-8 concentration in the three cistern samples was from 0.217 to 0.592 ug/1. Overall, the C-8 concentrations are lower in the two-mile radius samples man in me one-mile radius. While tfae groundwater well arid water*use survey and C-8 samplingwere being conductedinthewe- andtwo-mile radius m Ohio, groimdwater mo^^^^ conducted. One of me objectives of the groundwater modeling effort was to determine the likelihood that off-site migration of C-8 impacted groundwater was occurring. The groundwater modeling showed that no potential groundwater migration pathway exists beneath the Ohio River (DuPont, 2003a), Therefore, air transport of C-8 is the most likely migration pathway for C-8 from the facility. 3.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data 3.3.1 Monitoring of C-8 in Groundwater and Surface Water Groundwater Monitoring The Consent Order required that a select number of facility monitoring wells were to be sampled following the development of a groundwater monitoring plan by DuPont (DuPont, 2002c) and its approval by the GIST (DuPont, 20024). Frequency of sampling WWK-C-8 Data Summary " text final Pei>. 5,03 10 wnminatafi. re ASH02lg42 EID639874 c-spata summary Report___________.____Washington Works Facility was to be monthly for the first four months following the effective date of the Consent Order, then quarterly thereafter. Monthly sampling of groundwater began in January 2002. Quarterly samplingbegan in May 2002 (2002). The 4Q02 monitoring report was submitted to the GIST in December 2002 (DuPont, 2002k). Table 3,8 provides a list of the productionand monitoring wells included in the groundwater monitoring program for the facility. Well construction data and groundwater elevation data also are provided m this table. The three new bedrock monitoring wells (AJ06-MW02, N04-MW03, and Y14-MW02) that were installed in 3Q02 as part of the C-8 plume delineation work plan were added to the monitoring program in 4Q02. Figure 3.3 shows the location the wells listed in Table 3,8. Table 3,9 presents all of the C-8 concentrations measured in these productionand monitoring wells through October 2002, including C-8 data acquired prior to (he issuing of the Consent Order. The most recent data are listed first for each well. Figure 3.4 shows the October 2002 C-8 concentrations io groundwater. Table 3,9 shows that, in general, monitoring and production wells located on the eastern half of the facility have shown a C-8 concentration range from 0.071 to 2.82 ug/1 (AEl 1-MW01, AM07.PW01, A008-PW01, and AX13-PW01). Monitoring and production wells in the western half of the site generallyhave shown a C-8 concentration . rangeof0.117to51.2ug/l(V05-PW01,L04-PW01,N13-MW01,Y14-MW01, K16-PW01, West Well Field 1, E13-MW01, and-D08-MW01). Monitoring wells located adjacent to the Ohio River near the former Anaerobic Digestion Ponds have higher C-8 concentrations, ranging from less than 100 to 84,100 ug/1(P08-MW01, P04-MW02,004MW02 and R04-MW02). However, evaluation of boring logs for these well shows that three of these wells are screened in a perched water-table located in the clays and silts that Btratigraphicallyoverly the sands and gravels of the primary site water-table aquifer (site aquifer). Q04-MW02 is the only well included in the groundwater monitoring program located in the former Anaerobic Digestion Ponds area that is screened in the site aquifer. Recent C-8 concentrations measured for this well have been highly variable, ranging from 32.2 to 7,720 ug/1. (Further discussion of the wells screened in the perched water-table are presented in Section 3.5.1.) Available data for the bedrock aquifer are very limited (only three wells) but ranges from non-quantifiable [0.05 ug/1(NQ)] m the central southern boundary (Y14.MW02) to 0.133 ug/1along in the eastern portion (AJ06-MW02) of the site to 21.2 ug/1in the area near the former Anaerobic Digestion Ponds (N04-MW03). The next groundwater sampling event for the facility is scheduled for the first quarter 2003. Surface-water Monitoring The Consent Order also identified six outfalls1at the facility that are regulated by West Virgbua/National Pollutant Discharge Elimination System (WV/NPDES) Permit No. WV0001279 and where monthly sampling of C-8 was required. Figure 3.3 shows the locations of the'six outfalls. Monthly sampling of outfalls began in December 2001. The ' In this ttpoit, all surface-water samples identified as outlets, inlets, 01 outfalls will be refeired to collectively as (wtfelb. WWK-C-8 Data Swnmaty- text final Feb. 5.03 11 Wilmlnglon. DE ASH021643 EID639875 j^k- . c-e pa summary Raport_____________^_____Washinglon Works FacHHy November 2002 Surface Water Monitoring Report was submitted to the GIST in January 2003 (DuPont, 2003b). Table 3.10 summarizes the C-8 concentrations measured in the outfalls, including C-8 data acquired prior to the issuingof the Consent Order. The most recent data are listed first for each outfall. The six outfalls sampled dischargeprocess water and stormwater nmoffto the Ohio River. The WVDEP permit required monthly repotting of effluent flow volumes and C-8 concentrations. Outfalls 002,003, and 007 typically discharge effluent containing the lowest concentrations of C-8, ranging from NQ to 8.56, respectively. Outfalls 001 and 105 have dischargedhigher C-8 concentrations, ranging from 2.15 to 54.6 ug/1. Outfall 005 has shown the highest concentrations of C-8 and dischargesthe largest volume of effluent compared to the other outfalls at the facility. C-8 concentrations for Outfall 005 have ranged from 1.43 to 199 ug/1, with one anomalous highconcentration of 915 ug/1. However, the C-8 concentration at Outfall 005 has generallydecreased in 2001 and 2002 following the installation of a carbon filtration treatment system in the flouropolymers process. Outfall sampling for December 2002 has been completed, and (he monitoring report will be isawd to the GIST in February 2003. Outfall samplingfor January 2003 has been completed, but the C-8 results have not yet been validated. The next monthly outfall samplingevent is scheduled for February 2003. 3.3-2 Ohio River Water Quality Characterizing Ohio River water quality, with respect to C-8, was a Consent Order requirement. In addition, the evaluation river-water quality was identified as a data gap h the Compilation of Historical C-8 report (DuPont 2002b) and was included as a recommended activity in the C-8 Plume Identification Work Plan (DuPont, 2002e). The Ohio River Water Sampling Proposal for the facility and the Letart Landfill (DuPont, 20021)was developed and submitted to the GIST in January2002. Near the facility, Ohio River water was sampledto measure concentrations of C-8 in the Ohio River. The sampling investigation was designedto meet three main objectives: Q Characterize background C-8 concentrations in river-water upstream of the facility. Q Assess C-8 concentrations in river water along the facility reach. 0 Evaluate C-8 concentrations in river water downstream. Table 3.11 presents a summary of the Ohio River water sampling program, including samplingnear the Letart landfill. The Letart Landfill samples and C-8 results are . discussed in Section 5.4.5. Table 3.12 provides the C-8 results for Outfall 005. Figure 3.5 shows the location of upstream samples and samples along the facility reach. Figure 3.6 shows the concentration of downstream samples. C-8 concentrations for each sample are posted. In total, 46 river-water samples were collected, includingtwo duplicate samples. Adjacent to (he facility, river-water samples were collected at three locations along two transects across the river. Samples were collected at three depths(dip>mid-column, and WWIW8 Data Summaty - text final Feb. 5.03 12 WilmIngton.DE ASB021644 EID639876 C-B Date Summary Report__________________________Washington Works Facility bottom) at each location. Field parameters were monitored during collection ofeach sample. During the same time period that river water was sampled, effluent from Outfall 005 was sampled to evaluate dispersion downstream of the outfall. Of the sev&n samples collected upstream of the facility, six were ND> and one was NO. Of the 27 samples collected along the facility reach, all were ND except for two that were NQ. The range ofC-8 concentration for the 12 downstream sampleswas 0.0949 to 1.09 Tig/I. The two highest 08 concentrations were measured in a dip and mid-column samplecollected approximatelythree miles downstream from the facility. It is likely that the two highestC-8 concentrations measured in the Ohio River water are a 08 direct result of increased concentrations dischargedthrough Outfall 005. Table 3.12 08 shows that tha OS concentrations measured at Outfall 005 are highly variable. data were not collected ftom Outfall 005 between July 1 and July 10; but, if 08 concentration was higheron these days,-it might explain why the higher concentrations were measured in the river during this same time frame. The revised groundwater model showed that no potential migration pathway for 08 containing groundwater exists beneath the Ohio River. Therefore, air transport of OB to the Ohio River is a likely migration pathway, in addition to the direct dischargeof 08 containing surface water to the Ohio River through the permitted outfalls. 3.3.3 Public Water Supply Sampling PWS in West Virginia and Ohio at various points upstream of the facility were sampled pursuant to the Consent Order. Sampling of PWS within one-mile upstream and 10-miles downstream began in December 2001. Based on the 08 concentrations measured, the distance upstream and downstream was expanded. Sixteen PWS located as far as three miles upstream and 53 miles downstream were ultimately included in the samplingevents 08 (see Figure 3.7). Based on the very low concentrations measured at the various PWS, the number of PWS required to be sampled and the frequency of sampling were reduced by (he GIST in May 2002. Table 3.13 presents all the 08 concentrations measured in the various PWS. For PWS sampled more man once, the sampling event results are listed h chronological order. Cwently, only three PWS, Lubeck (West Virginia), Tuppers Plains (Ohio), and Little Hocking (Ohio) are sampled on a quarterly basis (DuPont, 2002m). 08 concentrations measured at Lubeck ranged from 0.283 to 1.21 ug/1, while 08 concentrations measured at Tuppers Plains ranged from ND to 0.726 ug/1(see Table 3.13). 08 Little Hocking had the highest concentrations of all the PWS sampled. 08 concentrations in production wells have ranged from 0.42 to 8.58 ug/1. 08 concentrations in drinkingwater dispersed to customers from these wells at the PWS have ranged from 1.69 to 4.29 ug/1. TW-4, a test well, had the highest measured 08 concentration at 37.1 ug/1. The concentrations measured at TW-4 have been steadily decreasing; the most recent result for this well was 14.5 ug/l. Based on these results, OEPA requested that an investigation be conducted to evaluate the C-8 concentrations at TW-4 and vicinity, and DuPont agreed to conduct the investigation. DuPont has sampled groundwater and soil samples from borings and collected groundwater samples from all the test and productionwells at Little Hocking. Groundwater results have been presented WWK-C-B Date Suiwiary - text final Feb. 5.03 13 Vfflmlngton.DE ASH02164S EID639877 08 Data Summaty Report Wa$hl ngton Works Facility to the OEPA. The method development for aannaallyyzziendgyCe-t8 Ainssaoirlessiuslts, tnilol ifninparlogress; tchoenrcelfuosrieo,nnsohnaevoefytehtebseoeinl sdarmawplnesfrhoams btheiesninvestigation. However, a report documenting the samplinginvestigationand the C-8 results for groundwaterand soil will be submitted to the OEPA and the GIST when the analytical results have been finalized. The nextPWS samplingevent at Little Hocking, Lubeck and TupporsPlains is scheduled for the first quarter 2003. 3.4 Task C; Plum Identificatlon/Qroundwater Assessment Based on the data gaps identified in the Compilation of Historical C-8 Data report (DuPont, 2002b), the C-8 Plume Identification/Oroundwater Assessment Work Plan was developed and submitted to the GIST (DuPont, 2002e). Included in this work plan were specificactivities recommended to fill the data gaps. In the following sections, each of the activities recommended in the C-8 plume delineation work plan is summarized briefly. Details of the activity status and the data acquired are then presented. 3.4.1 Installation of New Wells at the Washington Works Facility Three new bedrock monitoring wells were installed at the facility. These wells were groundwater installed to further delineate C-8 concentrations in groundwater, to evaluate flow direction and to determine the vertical groundwater gradients between the bedrock and the overlying sand aid gravel. Figure 33 shows the location of monitoring and productionwells, and the locations of the newly installed bedrock wells. Well construction diagrams for the new wells, AJ06MW02, N04-MW03 and Y14.MW02, are provided in Appendix A. Geologic data obtained during the installation of these three wells confirmed the depth to bedrock underlying the facility where these wells are located. These new data also permitted refinement of existing cross-sections that were developed for the facility. These revised cross-sections are discussed in detail in Section 3.5.1.1. 3.4.2 Hydroaeologic Testing of New Wells at the Washington Works Facility Hydrogeologic testing of the three new bedrock wells was recommended to evaluate aquifer characteristics of the underlying bedrock aquifer in the C-8 Plume Delineation work plan. The bedrock monitoring wells were clustered with or located near existing wells screwed in the primary site water-table aquifer. This allowed for the evaluation of mbeedvroecrtkicaaqlugifreard.ieOntnslbyeotnweeeronutnhde oprfiwmaatreyr sleitveewlsawtears-tmabelaesauqreudifefor ranthdestheewuenlldse(rOlycintogber 2002) and other wells nearby. The groundwater elevations indicate that at Q04-MW02 and surrounding sand and gravel aquifer wells, there is most likely an upward gradient between the groundwater in the bedrock and groundwater in the overlying sand and gravel near the former Anaerobic DigestionPonds area. 14 WWK.&8 Dala Sumrnaty - texl final Feb. 5.03 WIlnilnBton. DE ASH021646 EID639878 c^DateSmmiaiyReport______________Washington Works Facility At well cluster Y 14-MWO I and Y 14-MW02, located near the southern property boundary of the site, the groundwater gradient appears to be downward from the sand and gravel to the underlying bedrock. The water level measured in AJ06-MW02 in October 2002 is higherthan in wells located nearby that were measured in February 2002 indicatinga likely upward groundwater gradient from the bedrock to the overlying sands and gravel, in this area. 3.4.3 Washington Works Qroundwater Model Refinement A groundwater model was developedfor the facility as part of the RH report for WashingtonWorks (DuPom, 1999). This model was revised duringthis investigation partially to address the comments generated by the United Slates Environmental Protection Agency and the United States Army Coip of Engineers (USACOE). The Consent Order also required refinement of the groundwater model for the facility to reevaluate the extent of groundwater captured by the pumping wells at the site and to determina the likelihood that off-site migration of C-8 impacted groundwater is occurring, To meet these requirements, refinement of the groundwater modeling work was completed with input, guidance, and critical review from the United States Geological Survey, the USACOE, the West Virginia Department of Health and Human Resources, and GIST members during the model development, calibration, and Gnalization process. The report of final findings for the revised groundwater model for the facility and the surrounding area was submitted to the GIST in January 2003 (DuPom, 2003a). The revised groundwater model supports DuPont's previous conclusions that no off-site migration of groundwater is known to be occurring and that no potential groundwater migration pathway exists beneath the Ohio River. 3.4.4 Surface-water Field Reconnaissance at the Washington Works Facility Conducting field reconnaissance to identify additional surface-water features located onsite and sampling surface water from new locations identified during ttus effort was a C-8 plume delineation reoonunanded activity. Field reconnaissance was performed and no new surface-water features were identified beyond those locations that are currently sampled. 3.4.5 C-8 Monitoring in Groundwater and Surface Water at the Washington Works Facility Continuing to monitor C-8 in groundwater, in both the unconfined alluvial aquifer and underlyingbedrock aquifer (utilizing the newly installed bedrock wells), and in surface water at existing locations identified in the Consent Order was an activity recommended in the C-8 plume delineation work plan. The results of continued monitoring of groundwater and surface water are presented in Section 3.3.1. WWK-C-8 Data Summaly - text final Psb. 5,03 Wllrntngton,DE 15 ASH021647 EID639879 C-B Data summary Repon________ ________Washington Works Facility 3.4.6 Washington Works Facility Site Conceptual Model Refinement The final recommended activity for the facility is the integration of all the new data gatheredduring completion of Tasks A, B, and C into a revised site conceptual model (SCM). This activity was completed and the revised SCM is presentedin the following section. 3.5 Revised Site Conceptual Model The revised SCM ideally represents the current environmental setting (geology, hydrology, hydrogeology,groundwater flow, and water quality) and current human health and ecological exposure pathways at and surrounding the site. The following sections present fhe revised SCM in detail. 3.8.1 Current Environmental Setting Geology The facility rests on Quaternary alluvial terrace depositsin the Ohio River Valley. Figure 3.8, modified from Siroard (1989), is a model block diagram showingthe complex set of terraces and floodplams that formed in the Ohio Valley because of the glacial advances and retreats of the pro-, early- and late-Wisconsinan and the resulting successive phases ofalluvial.fills and the incisions into the alluvial fill by the Ohio River. Siroard (1989) identified five facies of the Ohio River Valley: sand and gravel (coarse-grained Ohio River alluvium or outwash); tributary sand and gravel; colluvium; silt and clay (fine grained Ohio River alluvium or overbank sediments);and sand and silt (eolian). A generalized north-south cross-section from the Little Hocking Water Association well field in Olao through the Ohio River and across the facility, is presented in Figure 3.9. This cross-section shows the Hplocene silt and clay overbank deposits that overlie the Pleistocene sand and gravel outwash deposits and the finer reworked Pleistocene alluvium, thoughtto underlie the river. The alluvial terrace deposits are underlain by a flat, river-scoured bedrock surface of the Dunkard Series thai rises steeply and forms the valley walls to the North of Little Hocking Water Association and to the south of the facility. Figure 3.0 shows the relatively flat topographyof the alluvial terrace deposits and the steep topography of the valley walls to the north and south. The detailed geology underlying the facility is shown on seven geologic cross-sections. Six of these cross-sections were developed during the Verification Investigation (DuPont, 1992) and revised in early 2002 for the Compilation of Historical Data Report (DuPont, 2002b) based on additional findingsftom the RFI. Further refinement of these six crosssections, based on the installation of three bedrock wells, and the generation of a generalized cross-section near the former Anaerobic Digestion Ponds were completed as part of the C-8 Plume Delineation Work Plan activities. Some of the test wells and monitoring wells portrayed in the cross-sections were temporary and no longer exist. Table 3.14 provides well construction information and groundwater elevation measurements for wells currently in existence at the facility. Figure 3.3 shows the locations of monitoring wells that currently exist at the site. The locations of the geologic WWK-O-8 Data Summary - text Knal Feb. 5.03 16 Wihiington, DE ASH021648 BI063&880 &-B Data Summary Report ________ Washington Works Facility cross-sections A-A' through P*F' are shown in Figure 3.10. The location ofO-O* is shown on Figure 3.17. Two cast-west cross-sections, A-A' and F-F' are shown in Figures 3.11 and 3.16. Four north-south cross-sections, B-B', C-C', D-D\ and E-E' are shown in Figures 3.12,3.13, 3.14 and 3.15, respectively. Cross-section G-G*, Figure 3.17, shows an expandedview of the riverbank area near the former Anaerobic Digestion Ponds and the Riverbank Landfill. Note that wells R04-MW02 and P04-MW02 are screened in a perched groundwater zone within the Holocene overbank deposits, The main and oldest Quaternary alluvial terrace at the facility is topographicallyflat and lies approximately50 feet above the Ohio River while the remains of younger terraces exist at lower elevations along the riverbank. The Holocene overbank depositsconsist of silt, sandy silt, clay, silty clay and clayey silt. The overhauls depositsare approximately 35 feet thick near the riverbank and decrease in thickness away from the riverbank. Under the central portion of the facility, these overbank depositsrange from approximately 5 to 15 feet thick. The overbank depositsare absent in the western portion of the site. The Quaternary alluvium (sand and gravel outwash deposits)ranges from 30 feet thick (near the river) up to 90 feet thick (under the central portion of die facility). The alluvium consists of coarsening downward unconsolidated poorly to well-sorted, brown and gray sand, silts, clay, and gravel. The Durikard Series bedrock consists primarily of red and varicolored sandy shale; gray, green and brown sandstone; gray and light gray siltetone; and minor beds of coal, claystone, black carbonaceous shale, and limestone. Hydrology, Hydrogeology and Oroundwater Plow Hydrology Surface water at the facility discharges through drains and stonn sewers (outfalls) and drainage swales. Six outfalls (001,002,003,005,007 and 105) collect facility process water and stonnwater runoffand dischargeit to the Ohio River. These six outfalls are regulated by WV/NPDBS Permit No. WV0001279. The locations of these outfalls are shown in Figure 3.3. Two drainageswales, one located in the facility's southwest comer, and the other located on the extreme eastern end of the facility, convey surface ninoff during rainy weather to the Ohio River. During dry weather, the drainage swales are dry. The main groundwater seep area at the Riverbank Landfill was identified, RBLL1 and sampled duringthe VI (DuPont, 1992). This seep likely originates from precipitation that has infiltrated topsoil or fill and Hows along the lop of the underlyingshallow clay and ultimately discharges along the riverbank (see Figure 3,3). An active French-drain groiMidwater collection system has been in operation at the Riverbank Landfill since 1991. The RFI verified (hat the collection system effectively captures water at the seep area (DuPont, 199$), Surface water from the seep is treated by a carbon filtration unit. This treated water discharges through Outfall 005 to the Ohio River. A second seep at the Riverbank Landfill (RBLL2) is located upriver from RBLL1 (see Figure 3.3). Seep water also is captured at this location by way of an active French-drain collection system. Seepwater is contained in an underground collection vessel that is WWK-C-a Pate Summary - text final Feb. 5,03 17 Wilmfnaton, DE ASB02164& BID 63 98 8 31 c-8 Data Summary Report Works Facility ___ _______________Washington pumped out periodically, and the seep water is treated at the wastewatel treatment facility on-site. ^^I Hydrogeology Regional groundwater.suppliesare obtained from the Dunkard Group bedrock and Ohio River alluvial ten-ace deposits. The saturated portion of the Ohio River alluvial terrace depositscomprisethe principalregional aquiferused for water supplypurposes. Production wells completed in this aquifer have been known to yield up to 500 gallons per minute (gpm)(Schultz, 1984). Based on these high yields, numerous industrial and commercial water supplycompanies obtain water from the alluvial aquifer. The yield from alluvial aquifer wells is related to the well's positionwith respect to the river, as well as formation grain size and thickness. The Holoceae silts and clays underlyingthe facility contain perched groundwater %ones. Along the riverbank, in the vicinity of the former Anaerobic Digestion Ponds, are seven monitoring wells that are completed in this perched groundwater zone (see Table 344). Groundwater elevations for these monitoring wells are typically 6 to 18 feet higher than elevations measured in monitoring wells completed in the underlying primary site watertable aquifer. During the February 2002 synopticwater level event, groundwater . elevations in the perched water table ranged from 571.91 feet above mean sea level (MSL) to 583,46 feet MSL: Croundwater elevations in (he underlying primary site watertable aquifer ranged from 552.15 to 566.62 feet MSL. Figure 3.17 shows a generalized cross-section for the area of the former Anaerobic Digestion Ponds showing the relationshipbetween the Ohio River (normal pool elevation of 582.0 feet MSL), the perchedwater table, and fee underlying primary site water-table aquifer. The primary site water-table aquifer occurs at a depthof about 60 to 70 feet bgs in the facilityarea. The saturated zone is approximately 30 to 40 feet thick, extending to the surface of the underlying Dunkard Group bedrock. The on-site production water wells completed in the site aquifer yield 200 to 450 gpm. The underlying Dunkard Group is not- a major aquifer. The upper zone at the Dunkard Group(Washington Formation)^ which consists primarily of shale and siltstone, bounds the lower extent of the site aquifer. Natural recharge to the alluvial aquifer comes from various sources, including: Q Infiltration ofprecipitation falling directly on the alluvium 0 Lateral movement of the river water through the alluvium via permeable sand and gravel zones 0 Seepagefrom stream tributaries that discharge to the Ohio River The maximum amount of water available to the alluvium dependson the degree of hydraulic connection to the river. The degree of hydraulic connection is a function of the penneability and thickness of the riverbed, permeability and thickness of the alluvium, and hydraulic gradient between the groundwater and the river. Pumping of on-site active well fields near and parallel to' the river (i.e., the Ranney Well, the DuPont-Lubeck Well Field, and the East Well Field shown in Figure 3.3) lowers the groundwater level in the alluvial aquifer to below river stage. This induces water from the river to flow into the WWK-C-B Data Sumrnaly- text final Feb.5,ft3 1B Wilmingten.DE ASH021650 EID639882 _ ft ^^ c-a Data summary Report______ __________Washington Works Facility alluvium toward the wells, which replaces water pumped from storage in the aquifer, and helps sustain high-yield pumping wells. In a 1990 hydrogeologicassessment, production well specific capacity testing of the DuPont-Lubeck Well Field and the East Well Field was conducted. The results were used to calculate the transmissivityand the hydraulic conductivity of the primary site aquifer (DuPont, 1990). In the vicinity of the DuPont-Lubeck Well Field, transmissivity values ranged between 114,900 and 127,500 gallons per day per square foot (gpd/ft). In the vicinity of the East Well Field, the transroissivity values ranged between 16,050 and 50,000 gpd/fl2.Hydraulic conductivity values were calculated from the transmissivity values for the East Well Field. For wells AX13-PW01 and AZ13-PW01, the hydraulic conductivity values ranged from 0.013 to 0,055 centimeters/second (cm/sec) and from 0.01 to 0.049 cm/sec, respectively. Using the hydrauiicconductivity values from the 1990 study and the hydraulic gradient values detennined from groundwater elevations measured in 1990 and assuming an effective porosity value for sand and gravel of 35 %, the groundwater flow velocity for several well pairs was calculated. The groundwater flow velocity was estimated at 5 feet/day (ft/d)between monitoring wells T13-MW01 and LI 8-MWOl in the southwest portion of the site, A groundwater flow velocity of 3 ft/d was estimated between monitoring wells P06-MW01 and K14-MW01 in the western central portion of the site. h the eastern portion of the site, a groundwater flow velocity of 2.5 ft/d was estimated for the site aquifer between monitoring wells AL10-MW01 and A009-MW01. Groundwater Flow As part of the C-8 plume delineation work plan, a thoroughevaluation of well survey data and well construction data was completed. This evaluation detennined that incorrect measuringpoint elevations were used in calculating groundwater elevations that had been included in the monthly and quarterly monitoring reports. Since this discovery, all groundwater elevation calculations have been redone and corrected values were included in the 4Q02 C-8 monitoring report. In addition, me groundwater elevation map for February 2002, the most recent groundwater measuring event where almost all site wells were included, has been revised using the corrected groundwater elevations and is shown in Figure 3.18. Overall, the revised map did not alter groundwater flow directions on- site. Figure 3,18 shows groundwater elevations and flow directions. It also shows flow rates on-site are strongly influenced by the Ohio River and by pumping ofon-site production ' wells. Normal pool elevation for the Ohio River is 582.0 feet MSL higher than the elevation of the primaiy site aquifer, indicating a gradient from the river to the primary site aquifer. The on.site production wells include the Ranney Well, a radial collector well which pumps 800 to 1,000 gpm; the seven wells in the East Well Field, which pump a combined average rate of 2,000 gpm; and the five DuPont'Lubeck wells, which pump about 700 gpm combined. A groundwater divide exists in the central part of the site with groundwater flowing to the east toward the Bast Well Field on the eastern side of the divide and to the west on the western side of the divide. Groundwater on the western side of the divide ultimately flows either back to the north toward the Ranney Well, or to the southwest toward the DuPont-Lubeck Well Field. From the northwestern corner of the WWK.08 Data Swinnaly- texl final Feb. 5,03 19 WIlmlngton, DE ASH021651 EID639883 M Data Summary Report_________________ Washington Works FgCilHy _______,, site, groundwater flows southeast toward the DuPonl-Lubeck Well Field. The revised groundwater model supports the interpreted groundwater flow direction generated using groundwater elevations measured in the monitoring wells (DuPont, 2003a). As discussed in Section 3.4.2, the vertical gradient between groundwater in the sand and gravel and in the underlying bedrock has not been verified, althoughpreliminary evaluation of available data indicates a predominantlyupward gradient especially near the river that potentiallymay be reversed near the groundwatermound/divide located under the central and eastern portion of the facility (seeFigure 3.18). The revised groundwater model supports an upward groundwatergradient between the bedrock and the overlying sand and gravel (DuPont, 2003a). Further data are needed to complete this evaluation and will be collected during future quarterlygroundwater monitoring events. Water Quality Groundwater Quality The available C-8 concentration data for groundwater at the site was presented in Section 3.3.1. These data show that concentrations of C-8 in the groundwater are variable with the highestconcentrations beingmeasured in wells screened in the perched water-table located near the former Anaerobic Digestion Ponds. Historic C-8 concentrations in these wells range from less than 100 to 84,100 ug/1. Groundwater from wells screened in the primary site water-table aquifer has much lower C-8 concentrations than those screened in the perched water table. In addition, C-8 concentrations are variable depending on location oftihe monitoirog well with respect to the locations of the pumping wells. Historic C-8 concentrations in wells located in the eastern half of the facility range from 0.071 to 2.82 ug/1. Historic C-8 concentration data for wells located in the western portion of the site are higher, ranging from 0.117 to 51.2 ug/1. Available data for the bedrock aquifer are very limited but range from 0.133 ug/1in the eastern portion of the site, to NQ along roe central southern boundary, to 21.2 ug/1 in the area near the former Anaerobic Digestion Ponds. The C-8 concentrations in groundwater from the monitoring wells screened in the perched water-table is not considered to be representativeof the primary site water-table aquifer. Based on measured water elevations in me wells, the perched groundwater in the fine-grained silts and clays of the Holocene ovcrbank depositsis most likely migrating downward into the underlying site aquifer. The rate of migration of groundwater from the perchedwater table to the underlying site aquifer is likely to be very slow because of the fine-grained sediments present in this area. Therefore, the contribution of the C-8 from the perehed groundwater to the overall site groundwater quality is likely to be minimal. In addition, the groundwater at the site is currently captured by the facility productionwells. Groundwater elevations at the site show that the site aquifer is recharged from the Ohio River and that groundwater at the site does not discharge from the ate aquifer to the river, C-8 concentrations in groundwater pumped at the site and used for potable or industrial purposes are significantlybelow the C-8 SL of 150 ug/1established by the CATT (WVDEP, 2002). For example, production well AM07-PW01 (historicallyknown as WWK-C-8 Data Swnmaiy " text final Feb. 5.03 20 Wilmington, 06 ASH021652 BID63&e84 MpaiasumrofyReport_______________Washington WorksiFagjiJty well 336) supplies potable water to the facility. 08 concentrations in groundwaler from AM07-PW01 have ranged from 0.071 (J) to 1.9 (L) ug/1. Surface-water Quality The available C-8 concentration data for surface water at the site was presented in Section 3.3.1. The six outfalls monitored at the facilityall discharge process water and stonnwater ronoffto the Ohio River. Outfalls 003 and 007 discharge effluent with the lowest concentrations of C-8, ranging from NO to 8.56 ug/1. Outfalls 002,001, and 105 dischargehigher concentrations ranging from 0-118 to 54.6 ug/1. Historically, Outfall 005 has shown the highest concentrations of C-8 and has dischargeda larger volume of effluent compared to the other outfalls at the facility with concentrations ranging from 1.43 to 915 ug/1. Note that the 915 ug/1 measurement is unusually high compared to the other values measured at this outfall and likely was a sample collected when the system was temporarily off-line. Excluding this anomalous measurement, the C-8 concentration range is from 1,43 to 199 ug/1. The C>8 concentration at Outfall 005 has decreased in 2001 and 2002 following the installation of a carbon nitration treatment system in the flouropolyroersprocess. Comparingthe highest measured C-8 concentration in effluent from the outfalls, 915 ug/1, to the CATT-established the Aquatic Life Advisory Concentration for C-8 (C-8 ALAC) of 1,360 ug/1shows that all values are lower than the criteria (Menzae-Cura & Associates, 2002). 3.5.2 Current Human Health and Ecological Exposure Pathways The main objective of the Consent Order was to determine whether there has been an impact on human health and the environment as a result of releases of C-8 to the environment ftom DuPont operations at the facility and the associated landfills (Local, Letart, and Dry Run). Therefore, human health and ecological exposure pathways both on-site (at the facility) and off-site (adjacent to the facility and the Local Landfill) were considered. The human health and ecological exposure pathway sections below describe the potential exposure routes for human and ecological receptors on- and off-site the facility/Local Landfill. Potential exposure routes were evaluated and classified as complete or incomplete. Table 3.15 summarizes the on-site and off-site human health and ecological exposure pathways evaluation for the facility. To be conservative, for each complete exposure pathways, the maximum C"8 concentration measured in the C-8 impacted aqueous media is compared to file C-8 SL, regardless of media type. On-Slte Human Health and Ecological Exposure Pathways . On-site human receptors include authorized facility workers and facility visitors. Ecologicalreceptors include animals living within the facilityboundaries. ;. Direct exposure to C-8 bearingmaterials contained within the Solid Waste Management Units (SWMUs) is limited or non-existent because these materials have been removed and regradedor paved (Riverbank Landfill, Burning Ground, Waste hicinerators, and Digestion Ponds) or covered and vegetated, hi addition, institutional controls (such as fencing) and excavation permits also limit exposure. Therefore, human and ecological receptor contact with these materials is considered to be an incomplete exposure pathway. WWW9 Data Summary- text final Feb. 5.03 21 Wilnitngton, DE ASH021653 EID639885 c-8 Date summary Report______________________Washington WorRs Facility A large portion of the facility is covered with asphalt and concrete. Surface-water contact with C-8 impacted soils or groundwater is not likely in these areas. Therefore, surface water contacting C-8 impacted soils is an incomplete exposure pathway. Much of the precipitationfalling on-site is routed toward drains and storm sewers, which ultimately discharge into the Ohio River. Precipitation falling on the rivet-bank slope either infiltrates into the soil or runs off to the river. The seeps that occur in places along the riverbank are likely caused by infiltration of precipitationthat accumulates above or in the low-permeability Holocene silt and clay overbank deposits that underlie topsoil and fill alongtine riverbank. Human receptor contact with impacted seep water is an incomplete exposure pathway due to the active French-drain groundwater collection system. Direct exposure to effluent discharging throughthe outfalls is an incomplete pathway because there are engineering and institutional controls (such as fencing) in place. Direct exposure to groundwater impacted by C-8 is also an incomplete pathway at the facility because groundwater is located at about 30 to 38 feet below ground surface (bgs) near fhe river bank and at 60 to 80 feet bgs under the central portion of the site. The only potential contact route for groundwater is via contact with water pumped from production wells. Water pumped from productionwells is used for two purposes: supplying drinking water and providing industrial process water. Well AM07-PW01 is the production well that providesthe majority of the drinking water to the facility. The other wells that provide drinking water at various times are A008PW01 and AQ09-PW01. Because AM07-PW01 provides drinking water, it was included in the groundwater monitoring plan for the facility. C-8 concentrations in groundwater from AM07-PW01 have ranged from 0.071 (J) to 1.9 (L) ug/1, These concentrations are significantlylower than the CATT-established C-8 SL of 150 ug/1(WVDEP, 2002). hi addition, average concentrations of C-8 in drinking water at point of use (which is a mixture of water from the three wells) will be lower than the maximum concentrations detected in any single well. Human receptors contact with impacted drinking/tap water is a complete exposure pathway. C-8 was detected in production wells providing industrial process water (K16-PW01, V05.PW01, and L04.PW01), The maximum concentration ofC*8 measured in these wells was 51.2 ug/1, detected in well V05-PWOL Water from these wells is not used for drinking, but rather for industrial processes including non-contact and contact cooling water, fire water, process water, conversion to demdneralized water to generate steam, and/or consumption in the manufacturing processes. There is a potential for limited contact. However, this contact is expected to be minimal due to the low duration and frequency of contact and because health and safety procedures in place are followed when working with or around process water. Average concentrations of C-8 in process water at the point of use (which is again a mixture of water from several production wells) will be lower than maximum concentrations detected in any single well. An ecological evaluation conducted as part of the RCRA Facility Investigation focused on identifying whether significant ecological resources may be exposed to site-related constituents released from the SWMUs (DuPont, 1999). This evaluation concluded that surface soil at the Riverbank Landfill/Digestion Ponds was the only potential ecological exposure medium within the RPI study area. However, topsoil and a vegetation cover WVW.-OS Date Summary - text final Feb. 5,03 22 WIlmlnglon.DE ASH021654 SI&639B86 c-spaia summary Report Works Facility _______________Washington prevent human and ecological receptor contact with surface soils (i.e., 0 to 1 feet), Therefore, the contact with surface soil at the Riverbank Landfill/Digestion Ponds is an incomplete exposure pathway. Surface-water contact with C-8 impacted soils or groundwater is not likely because the Waste Incinerators and Burning Ground SWMUs are covered with grave), asphalt, or buildings and do not provide ecological habitat. Subsurface soil (greater than 2 feet) and groundwater arc not exposure media of concern for ecological receptors, and groundwater does not dischargeto surface water at the site. Therefore, contact with surface water or groundwater or subsurface soil is considered an incomplete ecological exposure pathway. Off-Site Human Health and Ecological Exposure Pathways Off-site human receptors include residents using the water sources sampled during the groundwater well and water-use survey. Ecological receptors include livestock using the water sources sampled duringthe groundwater well and water-use survey. West Virginia One- and Two-Mile Radius Groundwater and Surface Water i 08 Direct exposure to impacted surface water and groundwater is considered to be an incomplete pathway in situations where the water source is not used. The pathway is considered to be a complete pathway in situations where the water source is used but the water is not used for drinking-water purposes, althoughthe exposure is considered to be minimal. The highest C-8 concentration in a non-drinking-water sample was 5.07 ug/1, well below the C-8 SL of 150 ug/1. The pathway is considered to be complete if the well s used for di-inking-water purposes. The highestC-8 concentration measured in drinking water was 2.8 ug/1,significantly lower than the CATT-established C-8 SL of 150 ug/1 (WVDBP, 2002), Therefore, even though the pathway is complete, it also is considered to be limited due to the low C-8 concentrations measured. An evaluation of ecological exposure to groundwater and surface water shows thai there is a complete pathway for exposure to livestock if these water sources are used for these purposes. Within the West Virginia one- and two-mile radius, the highest concentration of C-8 measured in water that was specified as a non-drinking-water source used for livestock is 5.07 ug/1,well below the CATT-established C-8 SL. Exposure of C-8 to ecological receptors is limited due to the low C-8 concentrations measured. Ohio One- and Two-Mile Radius Qroundwater and Surface Water As stated in the previous section, the exposure pathway for groundwater varies from incomplete to complete depending upon water use. Within the Ohio one- and two-mile radius, the highestdrinking-water C-8 concentration measured was 8.59 ug/1. This concentration is significantly lower than the C-8 SL of 150 ug/1 (WVDEP, 2002). While the pathway is considered to be complete, exposure also is considered to be limited. The pathway is complete for surface water because one spring used for drinking water within the one-mile radius was sampled. However, the C-8 concentration is low, 1.29 ug/1, compared to the CATT-established C-8 SL. An evaluation of ecological exposure to groitttdwater and surface water shows mat there is a complete pathway for exposure to livestock if these water sources are used for these purposes. Within the Ohio one- and two-mile radius, no water sources identified as a WWK-&8 Data Summqiy - text final Feb. 5.03 23 Wilmlngtoii. DE ASH021655 BID639887 c-eoato Summary Repori___________________Washington WorksFaciljty drinking water or non-drinking water were used for livestock. However, the highest C-8 concentration measured in a non-drinking-water sample, which may be used for livestock, was 23.6 ug/1. Ohio River Water Direct exposure to Ohio River water is a complete pathway, although the exposure is considered to be limited because river water is not directly used for drinking water. River water is ultimately the recharge source for PWS along the Ohio River. However, the highestC-8 concentration in the Ohio River water, 1-09 ug/1, is well below the C-8 SL. Public Water Supplies The highestC-8 concentration measured in connection with sampling related to PWS along the Ohio River was measured in a test well at Little Hocking Water Association, Ohio. However, this concentration does not represent the concentration of C-8 m drinkingwater suppliedto the public. The highestC-8 concentration measured in the drinking water from the Little Hocking well field was 4.29 ug/L Compared to the CATTestablished C-8 SL of 150 ug/1, this concentration is significantlybelow that level (WVDEP, 2002). The human health exposure pathway for groundwaler from the Little Hocking well field is complete because the water is used for drinking and non-drinking- water purposes. 3.6 Washington Works Facility Summary Many different activities were conducted at and around the facility in order to determine "'^ whether there baa been an impact on human health and the environment as a result of releases of C-8 to the environment from DuPont operations at the facility. The C-8 concentration in groundwaier and surface water from many sources (on-site, off-site, monitoring wells, production wells, private wells, springs,cisterns, river water, and PWS) was measured. More than 670 samples were analyzed. Based on all oflhe data evaluated for the Washington Works facility, the following observations were made: 0 The current exposure pathways are incomplete for human and ecological receptors contact with the following C-8 impacted media: On-site SWMUs On-site soil On-site surface water On-site groundwater o In addition, the current exposure pathways are incomplete for ecological receptors contact with the following C-8 impacted media: On-site drinking water On-site process water 0 Current on-site human receptors contact with C-8 impacted drinking water is a complete pathway. However, this pathway is considered to be inimmal because the highest C-8 concentration measured in drinking water at the site was 1.9 WWK^C-B Data Summary - text final Feb. 5,03 24 Wilmlngton, DE ASH021656 EID639888 C-B pata summary Report____________;______Washington Works Facjijty (L) ug/1, significantly lower than the CATT-established C-8 SL of 150 ug/l (WVDEP.2002). 0 Current on-site human receptors contact with C-8 impacted process water is also a complete pathway. However, this pathway is considered to be minimal because health and safety procedures are in place and followed when working with or around process water. The highest C-8 concentration measured in process water at the site was 51.2 ug/1, which is lower than the CATT-established C-8 SL of 150 ug/1. Q Current off-site exposure pathways for human and ecological receptors that are complete but minimal, due to the very low C-8 concentration measured, include residential and public drinking-water sources, residential non-drinking-water sources, and Ohio River water* For the drinking-water sources, the highestC-8 concentration measured was 8.59 ug/1,well below the C-8 SL of 150 ug/1. For the non-drinking-water sources, the highestC-8 concentration measured was ^ 23.6 ug/1, which is significantly lower than the C-8 SL of 150 ug/l. For Ohio ^ River water, me highest C-8 concentration was 1.09 ug/l, again significantly lower than the C-8 SL of 150 ug/1. Q The current revised groundwater model supports DuPont's previous conclusions that no off-site migration of groundwater is known to be occurring and that no potential groundwater migration pathway exists beneath the Ohio River. Q The current groundwater modeling observations combined with the current C-8 concentrations observed in groundwater, surface-water, and PWS in Ohio indicate lhat air transport of C-8 is the primary migration pathway for 0*8 from the facility to adjacent areas, C-8 transported in air emissions and depositedon surfaces is likely to be mobilized by precipitation and migrate via water transport to surface water and/or groundwater. Q Air transport of C-8 in.air emissions and water transport of C-8 directly dischargingthrough facility outfalls into the river are believed to be the sources of C-8 in the Ohio River. The highestC"8 concentration measured in Ohio River water was 1.09 ug/l. This C-8 concentration is significantly lower than the CATT established C-8 ALAC of 1,360 ug/l (Menzie-Cura & Associates, 2002). C-8 in the Ohio River is likely to be the source of C-8 in PWS located downstream of the facility. Q SWMUs on-site are believed to be the primary source of C-8 migration to groundwater. Air disposition of C-8 on the ground surface combined with surface water transport to groundwater also may have occurred. Q The current groundwater modeling observations combined with the current C-8 concentrations observed in groundwater at the facility also support potential migration of C-8 fi-om C-8 containing materials in the SWMUs directly into groundwater via water transport. WWK^>8 Data Summary - tort final Feb. 5.03 Wilmington, DE 2S ASH021657 EID639889 C-e Data Summary Report __________ Local landfill 4.0 LOCAL LANDFILL 4.1 Introduction The Local Landfill is located immediately south of the Washington Works facility and consists of three separate closed cells. The three cells operated from 1964 to the mid1980s under WV/NPDES Permit No, WV0076538 (see Figure 4.0). When the cells were closed, the cells were covered with approximately2 feet of low permeability soil and vegetative cover. Consent Order required tasks to be conducted at or immediately adjacent to the Local Landfill included the following: Q Task A: Groundwater Well and Water-Use Survey and C-8 Sampling--conduct a distance-phased groundwater well and water-use survey identifying and sampling all groimdwater wells, springs,and cisterns within a one-mile (and possibly twoand three- mile) radial distance of the facility and the Local Landfill. 0 Task B: Assessment of Existing Groundwater and Surface Water Monitoring Data--conducting monthly sampling for C-8 at Local Landfill at certain outfalls identified in WV7MPDES No. WV0076S38 as Outfalls 101,004 (Old), 004 (New), 005 (01d)/SS-l, and 005 (New). C-8 samples were to he taken from all me wells at the Local Landfill monthly for the first four months and quarterly thereafter. Q Task C: Plume Identification/Groundwater Assessment -detennine the vertical and horizontal extent of C-8 impacted groundwater at Local Landfill exceeding lug/I or as directed by the GIST, In Sections 4.2 through 4.4, discussions are presented of the specific activities conducted to meet the requirements of the Consent Order along with the results of the sampling activities. In Section 4.5, the revised site conceptual model that better represents the current environmental setting (geology, hydrology, hydrogeology, groundwater flow, and water quality) and current human health and ecological exposure pathways for the conditions at and smrounding Local Landfill is presented. 4.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling The WashingtonWorks facility is located immediately north of the Local Landfill. Because of the proximity of the facility to the Local Landfill, groundwater wells located within the combined one-mile radius (of both sites)in West Virginia were sampled. The results for the groundwater well and water-use surveying and samplingfor the facility and the Local Landfill are presented in Section 3.2.1 and 3.2.2. Briefly summarized, expansion of the one-mile radius was required by the GIST because the C-8 concentrations in five drinking-water sampleswithin the one-mile radius were above the 1 ug/1threshold level. Within the two-mile radius, only one drinking-water sample had a C-8 concentration above 1.0 ug/1. The results for the two-mile radius showed a trend toward lower concentrations than in the one-mile radius. Based on these results, and the WWtW-fl Data Summary - text final Feb. S. 03 26 WllmlnglOil, D ASH021658 EIt)638&0 C-8 Data Sumimaly Report Local Landfill establishment of the human health protective screening criteria for water (C-8 SL) of ISO ug/1by the CATT, the GIST determined that no farther o(T-site surveying around the facility and the Local Landfill was needed. 4.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data 4.3.1 Monitoring of C-8 In Groundwater and Surface Water Groundwater Monitoring The Consent Order required that all monitoring wells at Local Landfill were to be sampledfor C-8. The frequency of samplingwas to be monthly for the first four months following the effective date of the Consept Order, then quarterlythereafter. Monthly C-8 samplingofgroundwater began in December 2001 and quarterly samplingbegan in May 2002 (2Q02). Table 4.0 providesa list of the monitoring wells included in the groundwater monitoring program for Local Landfill. Well construction and groundwater elevation data also are providedin Table 4.0. At the time monitoring started, only four monitoringweUs existed at Local Landfill, LLMW-4, LLMW-6. LLMW-9, and LLMW-10. Another five wells were installed during 3002 as part of the C-8 plume delineation work plan, and these wells were included in the monitoring program starting in 4Q02. Figure 4.1 shows the location of the monitoring wells. Table 4.1 presents the C-8 concentrations measured in these monitoring wells, including C-8 data acquired prior to the issuance of the Consent Order, The most recent data are listed first for each well. At the present time, only general observations can be made from the five wells recently ^ included in the monitoring program because of the limited data set. Additional groundwater monitoring data will be obtained during me 1Q03 event. However, for the four wells with multiple C-8 measurements, some observations can be made, and the results for the new wells can be compared to the historical data available. LLMW-4, LLMW-6, and LLMW-13B show the highest C-8 concentrations ranging from 1.32 to 79.6 ug/1. Shallow, overburden well LLMW-11A, only sampledonce, had a C-8 concentration of 2.22 ttg/1. The other five wells at the landfill have lower concentrations, ranging from ND to 1.12 ug/1. The next groundwater-samptmg event for the Local Landfill is scheduled for the first quarter 2003. Surface-water Monitoring The Consent Order also identified three outfalls at Local Landfill (regulated by WV/NPDBS Permit No. WV0076538) where monthly C-8 sampling was to be performed. Outfalls 101,004 and 005. Monthly samplingof these three outfalls began in December 2001. In March 2002, two additional outfalls were added to the monitoring program due to a modification of the WWNPDES permit. [The names of the two of the outfalls already included in the monitoring program were modified. Outfall 004 was renamed Outfall 004 (Old), not to be confused with Outfall 004 (New) and Outfall 005 was changed to Outfall 005 (01d)/SSl, not to be confused with Outfall 005 (New).] WWK-C-8 Data Symmaly - text final Feb. 5.03 27 Wilniington.De ASH021659 EID639891 C-8 Data Summary Report Local Landfill Figure 4.1 shows the locations of the five outfalls in the monitoring program. The two 004 outfalls monitor a stream on the north side of the property and the two 005 outfalls monitor a stream located on the western side of the property. Both of these streams discharge stonnwater runofffrom the landfill. Surface water in the two 004 outfalls ultimately dischargeto Pages Run, which crosses the facility and enters the Ohio River. Surface water in the two 005 outfalls crosses through the facility in stonnwater pipesand ultimately discharges throughOutfall 003 to the Ohio River. Outfall 101, located along the northeast perimeter of the landfill property, is located in a plasticsewer pipethat conveys seep water and leachate from a series of three holding ponds located on the east side of the landfill cells in addition to stonnwater runoff. Water passingthrough Outfall 101 is conveyed via the sewer pipe to the Washington Works facility and ultimately dischargesthrough Outfall 001 into the Ohio River. LM1 (Leachate)is a surface-water point that monitors leachate entering Pond 2, one of the holdingponds (hat then discharge through Outfall 001. LMl (Leachate) and is monitored bi-annually for C-8. Table 4.2 provides the C-8 concentration data for the outfalls, including C-8 data acquiredprior to the issuing of the Consent Order. The most recent data are listed first for each outfall. Outfall 101 is the only outfall that has consistentlyhad flow since the beginning of the C-8 monitoring program. The other four outfalls have had no-flow conditions for the past three months, most likely due to the drought. The concentrations of C-8 in both 004 outfalls have been in the 10-15 ug/1range, while the concentration in the both 005 outfalls have been higher, in the 20 to 50 ug/1range. Outfall 101 has shown a wider range of C-8, from 12to 115 ug/1. LM1 (Leacbate) has had the highest C-8 concentration at Local Landfill (120 ug/1). Outfall sampling for December 2002 has been completed, and the monitoring report will be issued to the GIST in February 2003. Outfall sampling for January 2003 has been completed, but me C-8 results have not yet been validated. The next monthly outfall sampling event is scheduled for February 2003. 4.4 Task C: Plume IdentSfication/Groundwater Assessment Based on the data gaps identified in the Compilation of Historical C-8 Data report (DuPont, 2002b), the C-8 Plume Identification/Groundwater Assessment Work Plan was developed and submitted to the GIST (DuPont, 2002e). This work plan included specific activities recommended to fill the data gaps. In the following sections, each of the activities recommended in the C-8 plume delineation work plan is summarized. Details of the activity status and tfie data acquired are then presented. 4.4.1 C-8 Monitoring inGroundwater and Surface Water at Local Landfill Continuing to monitor C-8 in groimdwater in the overburden and in the underlying bedrock aquifer (utilizing the newly installed monitoring wells), and in surface water at existing locations identified in the Consent Order, was an activity recommended in the C-8 plume delineation work plan (DuPont, 2002e). The results of continued monitoring ofgroundwater and surface water are presented in Section 4.3.1. Monitoring of C-8 in groundwater continues on a quarterly basis, while surface-water monitoring of C-8 is conducted on a monthly basis. WWK-M Data Summary - text final Feb. 5,03 28 Wllmington, DE ASH021660 BID 639892 C-8 Data Summary Report______________________ L00?1Landfiil 4.4.2 Surface-water Field Reconnaissance at the Washington Works Facility Conducting field reconnaissance to identify additional surface-water features located at die Local Landfill and samplingsurface water from new locations identified during this effort was a C-8 plume delineation recommended activity. Field reconnaissance was performed, and no new surface-water features were identified. 4A3 Installation of New Wells at Local Landfill The installation of four additional well clusters (overburden and bedrock) was proposed in the C-8 plume delineation work plan to farther characterize the bedrock stratigraphy under the site, to further delineate C-8 concentrations in groundwater, and to evaluate groundwater flow direction. One well cluster, LLMW-11 A and B and three bedrock wells, LLMW.12B, LLMW-13B, and LLMW-14B were installed during 3002. The overburden wells were not installed at three of the proposedwell cluster locations because very little overburden was encountered and the overburden was dry. Figure 4.1 shows the locations of all monitoring wells at the Local Landfill including the locations of the newly installed monitoring wells. Well construction diagrams for the new wells, are provided m Appendix B. The geological logs for the five wells installed in 3Q02 confirm previous interpretations of subsurface conditions at die site. fa general, some thickness of clay and weatfiered bedrock (shale, sandstone, and/or siltstone) is underlain by unweathered bedrock, which consists of alternating layers of shale and layers of sandstone and/or siltstone. Where the data were available, it confirmed that the Hthologic units dip slightlytoward the north. The new geological data were used to refine the geologicinterpretationused for the revised SCM which is presented in detail in Section 4.5.1. 4.4.4 Local Landfill Site Conceptual Model Refinement The final recommended activity for the Local Landfill was the integration of all the new data gathered during completion of Tasks A, B, and C into a revised SCM. This activity has been completed, and the revised SCM is presented in the following section, 4.5 Revised Site Conceptual Model The revised SCM better represents the current environmental setting (geology, hydrology, hydrogeology, groundwater flow, and water quality) and current human health and ecological exposure pathways for the conditions at and surrounding the Local Landfill. The following sections present the revised SCM in detaiL 4.5.1 Current Environmental Setting Geology In 1989, eight monitoring wells were installed at the Local Landfill by Tetra Tech Richardson (LLMW-1 through LLMW.8). However, five of these monitor wells (LLMW-1, LLMW-2, LLMW-3. LLMW-5, and LLMW-7) were closed in 1996 because the wells were screened in the discontinuous shallow clays and underlying weathered WWK-0.8 Date Summaly - text final Feb. 5.03 29 Wllmlnglon, DE ASH02l$61 EID639893 C.8 Data Summary Report______________________________________^pMJ-3"^^ bedrock. LLMW-8, a bedrock well, was closed in 1997. Two additional bedrock wells, LLMW-9 and LLMW-10 were installed in 1995 and 1997, respectively. LLMW-9 was installed as a background well. These two wells are screened within a sandstone layer that was selected as the significant underlying aquifer for SW/NPDES permit monitoring. Table 4.0 summarizes the well construction data for the existing monitoring wells. Five additional wells, LLMW-11A, LLMW-11B, LLMW-12B, LLMW.13B, and LLMW-14B were installed at Local Landfill in 3Q02 as part of the C-8 plume delineation work plan (DuPont, 2002k). The locations of three cross-sections developed for (he Local Landfill are shown in Figure 4.2. Two cross-sections, A-A' and B-B', were presented in the Compilation of Historical Data Report (DuPont, 2002b) and have been modified to include data not previously available for LLMW-9 and LLMW-10. In addition, LLMW-12B, a newly A^ installed well, was projectedonto B-B'. nins west to east through the central portion of Local Landfill, B-B' runs north to south. Cross-sections A-A' and B-B' are shown in Figures 4.3 and 4.4, respectively. Cross-section C-C', shown in Figure 4.5, is a new cross-section that starts in the south and runs north, and then runs to the east, showing the geologicaldata obtained from many of the newly installed monitoring wells. The Local Landfill is situated in a hilly area with high relief, up to 100 feet in some valleys, and lower relief of approximately 10 to 25 feet at the landfill cells. The slopes appear to be a combination of natural topographywith terraced outcrops of massive sandstone and siltstone underlyingvarying amounts of soil cover and man-made landfill plateaus. A shallow, tight, clay overburden layer lies at the surface and ranges from 3 to 25 feet thick. The clay can contains some minor sandy and silty zones, and some pebbles and fragments of sandstone in some locations. The clays are of low plasticity and appear to be well compacted, often displaying a laminar structure (DuPont, 1990). Underlying the shallow clay layer is weathered shale, weathered sandstone, and/or weathered siltstone zone ranging from 10 to 35 feet thick (see Figure 4.3). Below this weathered bedrock, at depths ranging from 21 to 40 feet bgs, competent bedrock is present (see Figures 4.3,4.4, and 4.5). The bedrock at the Local Landfill consists ofinter-bedded red and varicolored sandy or calcareous shale, and gray, green, and brown sandstone and siltstone of the Permian age Dunkard Group. Cross-section B-B' (see Figure 4.4) shows that the sandstone layers dip gently toward the north. Most of the sandstone layers located in the upper portion of the siratigraphic section are lenticular and laterally discontinuous. However, four laterally continuous sandstone and/or siltstone layers are located hi the lower stratigraphic section (see Figures 4.3,4.4, and 4.5). These water-bearing units are referred to as A-Zone (the "underlying significant aquifer"), B-Zone, C-Zone, and D-Zone. These four zones are labeled on the cross-sections and are discussed in detail in the hydrogeology section that follows. Hydrology, Hydrogeology and Groundwater Flow Hydrology In general, infiltration of precipitation is limited due to the very low hydraulic conductivity (5 x 10'7 cm/sec) of the surfieial clays (where these clays exist) and the WWK-C-8 Data Summary- text teal Feb. S. 03 30 Wllmlngton, DE ASB0216e2 EID63&894 C-fl Data Summafy LandfHI Report____________________________________j-pcal weathered bedrock (DuPont, 1992). In addition, infiltration of precipitation into the cells is limited by a surface cover that includes approximately 2 feet of low permeability soil and vegetation. Storm runoff flows into two streams, one located on the northern side of the property and one located on the southern side of the property. Surface water in these two streams is monitored. Outfalls 005(01d)/SS-l and 005(New) monitor surface water in the northside stream and Outfalls 004(01d) and 004(New) monitor surface water in the south-side stream. For the past few months, no-flow conditions have been observed at Outfalls 004 and 005, indicating that these streams have no base flow. Leachate from the southern cell and the eastern cell Hows from the seeps in the steep valley walls to leachate collection ponds. Pond 1,2, and 3 (see Figure 4.1). However, during the recent drought conditions of 2002, many seeps, which normally do flow, were not observed flowing. The lack of observedflow mffybe'a result of-the drought-conditions,t-eiffihatefirom theseponds is dischargedinto a pipeline. Monitoring of combined pondeffluent conveyed in the pipelineis conducted at Outfall 101. Pond effluent is conveyed through Outfall 101 to the facility where it passes through stormwater Outfall 001 into the Ohio River. Hydrogeology Groundwater underlying the Local Landfill occurs in multiple stratigraphic units. A discontinuous upper layer consists of the clays and underlying weathered bedrock and has a very low hydraulic conductivity (DuPont, 1992). The lower layers consist of the continuous and discontinuous sandstone units having low permeability of 1 x 10'5 can/sec. The lower sandstone and/or siltstone layers are now identified as the A-Zone, B'Zone, C-Zone, and D-Zone based on re-evaluating the old geologicand hydrogeologic data and the new data obtained while installing and monitoring the new wells at Local Landfill. These four zones are indicated on the cross-sections wherever possible (see Figures 4.3, 4.4, and 4.5). The A-Zone throughD-Zone are separated by laterally continuous shale layers. Well yields from the sandstone and siltslone layers are very low, ranging from <0.5 gpm to 1.5 gpm (DuPont, 1992). The highest laterally continuous sandstone layer is located at elevations between 710-740 feet above MSL (see Figures 4.3,4.4, and 4.5) and is designated as the "underlying significant aquifer." This unit is currently monitored semiannually as required by the permit at monitoring wells LLMW-4, LLMW-6, LLMW.9, and LLMW-10. Based on the new geological data obtained, mis unit also will be referred to as the A-Zone. The A-Zone outcrops in the western, northern, and eastern valley walls of the property. The next lower sandstone unit is designated as the B-Zone and is monitored via LLMW-12B. The B-Zone is located at elevations between approximately 665 and 694 feet above MSL, The B-Zone also should outcrop in the western, northern, and eastern valley walls of the property. The C-Zone is the next lower sandstone/siltstone unit and is monitored throughwells LLMW-13B and LLMW-14B. The C-Zone is located at elevations between approximately 612 and 640 feet MSL. LLMW-11A, located to the south of one of the landfill cells, may be screened in a weathered portion ofC-Zone. The screen is located at the correct elevation for C-Zone, and the lithology there is described as clay overlying silt WWK-C-fl Data $ummaiy - text final Feb. 5,03 31 Wilinlngtoti, DE ASH021663 EID639895  \ C-Steta Summary LandfJH Report_____._______________________LpCal and sand. However, because it is located in a valley, the clay, silt and sand could be recent depositsinstead of weathered bedrock. In addition, because there is stream nearby, there is likely to be a component of surface-water interaction involved at this location when the stream flows. The Outlets 004(01d) and 004(New)which monitor this stream, were dry duringAugust, September, and October 2002. Based on the data available, LLMW-11 A is considered to be part of the C-Zone monitoring wells. The lowest elevation on the north edge of the Local Landfill and the southern edge of the Washington Works facility is approximately 650 feet MLS. The highest elevation of C-Zone, approximately 640 feet MLS, is about 10 feet lower than the surface elevation indicating that this zone is not exposedat the surface but more likely, the edge of this zone contacts the alluvial material directly. The D-Zone is the lowest hydrogeologic unit encountered, 545 to 562 feet MSL, and is made up ofsiltstone and sandstone. LLMW-11B is the only well that was drilled deep enough to encounter the D-Zone; therefore, little information about (he lateral continuity of this unit is available. This unit may have been encountered at LLMW-1; however, the distance between these two wells is too far to extrapolate the data. The D-Zone also does not outcrop on the surface and most likely contacts the Pleistocene alluvium directly in the subsurface. Groundwater Flow Groundwater elevations have been measured semiannually since 1994. Groundwater elevation contour maps for the significant underlying aquifer (A-Zone) have been prepared from these data as required by the WV/NPDES Permit No. WV0076538. Figure 4.6 presents the groundwater elevation map for 4Q02 for the A-Zone. A groundwater elevation map for 4Q02 for the C-Zone is presented in Figure 4.7. Note that data from LLMW-11A was used to make this map because the outfalls monitoring the stream next to these wells showed no-How conditions. It was assumed that water elevations in this well were not highly influenced by surface water. Comparing Figures 4.6 and 4.7 shows that in general, groundwater in these two zones basically flows the same direction, toward the northwest. The direction of groundwater flow in the B-Zone and the D-Zone cannot be determined with the limited data available; however, groundwater flow in these two zones is likely to be similar to that observed ro A-Zone and C-Zone From a regional perspective, all bedrock groundwater is expected to generally flow north toward the Ohio River alluvial valley. Evaluation of limited groundwater elevation data for the closed wells (based on well installation information) indicates a downward vertical gradient between the upper discontinuous water bearing zone and the lower sandstone layers containing the underlying significantaquifer (A'Zone). Evaluation of groundwater data for the A-Zone and the C-Zoxie and of limited groundwater elevation data for the monitoring wells in the B-Zone and the D-Zone also indicates a downward vertical gradient between the zones. The sandstone/siltstones of the A-Zone (the underlying significant aquifer) and the B-Zone outcrop in the valley walls adjacent to the facility where groundwater discharge may flow downslope within the fractured rocks of the valley walls and ultimately enter the Quaternary alluvial terrace deposit underlying the Washington Works facility. Alternatively, groundwater also may discharge as seeps in the valley walls. Groundwater WWK-C-8 Date Summary - text final Feb. 5.03 32 WiWngtwi, DE ASH021664 EID639896 C-8 Data Summary Report_____ LancHJH _______________________Local from the A-Zone and B-Zone that discharges to seeps ultimately migrates to the facility through a number of pathways. It can discharge downward to leachate collection ponds and pipes (Outfall 101) and flow to the facility where it enters storm sewers and dischargesto the Ohio Riven Oroimdwater also can seep to small streams draining the property to the north [monitoringpointsOutfall 005(01d)/SS-l and 005(New)] and flow to the Quaternary alluvial terrace unconfined aquifer where pumpingofon-site active well fields controls groundwater flow, Groundwater seeps in the southern valley wall can seep to the small stream that drains the southern part of the property and ultimately flows toward the north back on to the facility [Outfalls 004(0ld) and 004(New)]. Groundwater from C-Zone and D-Zone, which are located in the bedrock at elevations lower than the alluvium surface, likely dischargesto the alluvium in the subsurface. Groundwater flow in the alluvial aquifer, adjacent to the valley walls of the Local Landfill, is toward the pumpingwells located near and parallel to the Ohio River. The pumping of these well fields lowers the groundwater level in the alluvium to below river stage, inducing surface water from the river to flow into the alluvium and toward the pumping wells. Water Quality Groundwater Quality Table 4.1 presents the data available for C-8 in Local Landfill monitoring wells. C-8 concentrations in the A-Zone, the underlying significant aquifer, are highestat LLMW-4 (maximum of 79.6 ug/1) and at LLMW-6 (maximum of 19.9 ug/1). These two wells are positioned adjacent to landfill cells and are the downgradient wells within the A-Zone. Monitoring well LLMW-10, located under a landfill cell and upgradient ofLLMW-4, has shown a range in C-8 concentration of 0.15 to 1.12 ug/1. Monitoring well LLMW-9, an upgradient well located to the southwest of one of the landfill cells has shown C-8 concentrations ranging from non-detectable to 0.14 ugfl. These data indicate that C-8 fiom the landfill cells (and/or from air deposition) is migrating downward and reaching groundwater within the A.Zone. Water levels in the A-Zone show groundwater flowing from the southeast to the northwest within this zone. The C-8 concentration measured from the one well screened in the B-Zone (LLMW-12B) is very low, 0.0658 ug/1. Groundwater flow gradientsindicate a downward gradient from the A-Zone to the B-Zone, which could be the migration pathway for C-8 to reach the B-Zone. However, goundwater flow with the B-Zone is toward the facility in the northwest and away fiom the one- and two-mile sampling area. C-8 concentrations for the one round of data for wells in the C-Zone, LLMW-11A, LLMW-13B, and LLMW-14B, are higher, 2.22,6,61, and 0,488 ug/1, respectively, supportinga downward vertical gradient for groundwater from the A-Zone to the B-Zone to the C-Zone as indicated by groundwater elevations. Groundwaler flow in the C-Zone is Hkety to be in the same direction as in the A-Zonc and the B-Zone, to the northwest. The one C-8 value from the D-Zone is NQ (LLMW-11B). This may indicate that downward migration of C-8 to the D-Zone has not taken place. However, the location of this well is upgradient of the landfill cells WWK-C-B Data Summary "text final Feb. 5.03 33 Wllmington. DE ASB021665 EID639897 C-8 Data Siimmay Report Local Landfill Groundwater flow in all zones monitored at the Local Landfill is toward the Washington Works facility (northwest). It is unlikely that C-8 impacted groundwater from any of the zones at Local Landfill would have migrated off-site into the one- and two-mile radius sampling area because of this northwest flow direction. Surface-water Quality C-8 concentrations in surface water are presented in Table 4.2. Outfall 101 monitors stormwater ninoffand effluent from the leachate ponds and seeps that drain into the ponds. Outfall 101, which has never had no-How conditions while it has been monitored, has had the highestC-8 concentration measured in surface water at Ucal Landfill, ranging from 12 to 115 ug/L The C-8 concentration measured in a sample from tolet 002 [LM1 (Leachate)], which collects seep water flowing to Pond 2, was 120 ug/1, in November 2002. Outfalls 004(01d), 004(Mew), and 005(01d)/SS-l and 005(New) are monitoringpoints , located along two streams on the southern and northern sides of the property, respectively. These outfalls collect stornwater runofTfrom the landfill cells. These four outfalls have all had no-flow conditions for the past several months. However, Outfall 005(01d)/SS-l historically has shown the highest C-8 concentrations of these four outfalls, ranging ftom 6.8 to 51.4 ug/1. 4.8.2 Current Human Health and Ecological Exposure Pathways The main objective of the Consent Order was to detemune whether there has been an impact on human health and the environment as a result of releases of C-8 to the environment from DuPont operations at the Washington Works facility and the associated landfills (Local, Letart, and Dry Run). Therefore, human health and ecological exposure pathways both en-site (at the Local Landfill) and off-site (adjacentto the facility and the Local Landfill) must be considered. The human health and ecological exposure pathway sections below describe the potential exposure routes for human and ecological receptors on- and off-site. Potential exposure routes were evaluated and classified as complete or incomplete. On-Slta Human Health and Ecological Exposure Pathways Current Environmental Setting This section describes the potential exposure routes for human and ecological receptors that are found at the Local Landfill, On-site human receptors include authorized facility workers and facility visitors. Ecological receptors include animals living within the landfill boundaries. Potential exposure routes were evaluated and classified as complete or incomplete and are summarized in Table 4.3. Table 4.3 summarizes the human health and ecological exposure pathway evaluation for the Local Landfill. To be conservative,. for each complete exposure pathway, the maximum C-8 concentration measured in the C-8 impacted media is compared to the C-8 SL, regardless of media type. Access to the Local Landfill is restricted by electronic and locked gates at the road entrances. However, a posted nature trail has been established on the east side of the landfill property. The trail loops around the eastern part of the landfill starting and WWW-6 Date Summaly - text final Feb. 5,03 34 Wilmifigton. DE ASH021666 EID639898 C.B Data Summary Raport__________________________.-..- Local Landfill ending near the landfill's electrically operated gate. The nature trail is a marked trail and does not come near the cells. Access to the site from surrounding roads is possiblebut is discouraged due to the heavily wooded nature of the property and the hilly terrain. The three cells at the Local Landfill are covered with a low permeabilitysoil and vegetative cover. This cover prevents human and ecological receptors' exposure to the landfilled materials. Permit WV0076538 requires that the landfill surface will be inspected quarterly for evidence of cracking or erosion (which could allow surface water to enter the solid waste deposit)and evidence of settling of solid waste (causingponding of surface water). Per Condition G-16 of the permit, a stonnwater erosion inspection is conducted annually. Therefore, human and ecological receptors' exposure to C-8 containing landfilled materials is an incompletepathway. At the landfill, precipitation is expected to take one of two paths. It may infiltrate downward throughthe vegetated soil cover and into the cells, although, the low petttieability of the soil cover reduces the amount of infiltration. If the precipitation does infiltrate the soil cover, it will possibly encounter the landfill materials and will continue migrating downwards. It may be prevented ftono farther downward migration by the low permeability clays and weathered bedrock. However, if this water does migrate farther downward, it should encounter the sandstones and shale layers. Groundwater flowing through the sandstone layers that outcrop in the valley walls located above the facility's southern edge would be exposed at the surface in seeps, if seeps exist. No seeps were identified in the valley walls during field reconnaissance. Seeps near the leachate collection ponds flow almost continuously althoughthe amount of flow is variable. Contact with leachate from the landfill cells that has reached the ponds and surface water via these seeps is possible and therefore, is a complete exposure pathway for human and ecological receptors. However, contact would be very rare since only facility representatives enter this area on an infrequent basis. Thfthighest C-8 concentration measured in leachate from Local Landfill 120 ug/1, which is lower than (he CATTestablished C-8 SL of 150 ug/l (WVDEP. 2002). . Depths to groundwater at the Local Landfill ranges from around 20 feet to 130 feet bgs (see Figures 4.3,4.4, and 4.5). In addition, groundwater has not been observed seeping in the valley walls indicating that ground water is not exposed at ground surface on valley walls, but most likely flows in the subsurface of the valley walls- Therefore, contact with C-8 impacted groundwater as an exposure pathway to human or ecological receptors is considered to be incomplete, Off-site Human Health and Ecological Exposure Pathways ' Off-site human receptors include residents using the water sources sampled during the groundwater well and water-use survey. Ecological receptors include livestock using the water sources sampled during the groundwater well and water-use survey. West Virginia One- and Two-Mile Radius Groundwater and Surface Water Results for the West Virginia one- and two-mile radius groundwater and surface water was presented in Sections 3.2.1 and 3.2.2. The exposure pathway is incomplete if the water source is not used. The exposure pathway for human and ecological receptors is complete if the water source is used for drinking water. The exposure pathway is WWK-&B Data Summary - text final Fab. . 03 35 Wllrnroton, OE ASH021667 EI0639899 C-8 Data Summaty Report_____ ________________________________Local Landf'lH complete if the water source is used for non-drinking-water purposes, although, the exposure is considered to be minimal because the water is not ingested. The highest C-8 concentrations for non-drinking-water and drinking-water sources was 14.3ug/l and 2.8 ug/1, respectively, which are significantly below the CATT C-8 SL of 150 ug/1. The pathway is complete but exposure is limited due to the low C-8 concentrations. 4.6 Local Landfill Summary Many different activities have been conducted at and around the Local Landfill in order to determine whether there has been an impact on human health and the environment as a result of releases of C-8 to the environment from the landfill cells at the Local Landfill. The C-8 concentration in groundwater and surface water from many sources (on-site, offsite, monitoringwells, production wells, private wells, springs, and cisterns)was measured. Based on all of the data evaluated for the Local Landfill, the following observations were made: Q The current exposure pathways are incomplete for human and ecological receptors contact with the following C-8 impactedmedia: On-site landfilled materials On-site soil On-site groundwater Q Human and ecological receptors contact with on-site leachate and C-8 impacted surface water are currently complete pathways. However, these pathways are considered to be linuted because of health and safety practices followed when managing the leachate and because of institutional controls in place to limit access to the site. The highest C-8 concentrations measured in leachate and surface water at the site were 120 and 115 ug/1, respectively, which are lower than the CATT-established C-8 SL of 150 ug/1 and the Aquatic Life Advisory Concentration for C.8 (C-8 ALAC) of 1,360 ug/1(WVDEP, 2002; Menzie-Cura & Associates, 2002). Q Current off-site exposure pathways for human and ecological receptors that are complete but limited, du6 to the very low C-8 concentrations measured, include residential drinking and non-drinking-water sources. For the drinking and non- driridng-water sources, the highest 08 concentrations measured were 2,8 and 5.07 ug/1, respectively. These concentrations are well below the C-8 $L of 150 ug/1. 0 Evaluation of the C-8 results measured at Local Landfill and the groundwater flow directions indicates C-8 migration via water transport from Local Landfill does not occur in any direction other than toward the Washington Works facility in the northwest but outside the boundary of the facility and the Local Landfill. Q C-8 detected at locations within the one- and two-mile radius is believed to have been transported from the Washington Works facility via air emissions. C-8 transported in air emissions and depositedon surfaces is likely to be mobilized by precipitation and migrate via water transport to surface water and/or groundwater. WWK-C-8 Data Summary - text final Feb. 5,03 36 WamnBton, DE ASH021666 EID639900 C-B Dala Summary Report Letart Landfill 5.0 LETART LANDFILL 5.1 Introduction The Letart Landfill is located about 46 river miles downstream of the Washington Works facility, north of the town of Letart in Mason County, West Virginia (see Figure 5.0). The landfill was operated and closed under WV/NPDES Permit No. WV0076066. The Letart Landfill was permanently closed by installing an engineeredmulti-layer geosyntheticand soil cap (DuPont, 2001). Included in the closure activities were the installation of a leaehate collection system, erosion and drainage control measures, and chain-link fencing. The cap construction was completedin April 2001. The permit requiresquarterly groundwater monitoring, surface-water monitoring, and engineered cap maintenance. Consent Order required tasks that were to be conducted at or immediately adjacent to the Letart Landfill included tfae following: 3 Task A: Groundwater Well and Water-Use Surveyingand C-8 Sampling-conduct a distance-phased groundwater well and water-use survey identifying and sampling all groundwater wells, springs, and cisterns within a one-mile (and possiblytwo- and three- mile) radial distance of the Letart Landfill. 0 Task B: Assessment of Existing Groundwater and Surface Water Monitoring Data--conduct monthly sampling for C-8 at Letart Landfill at certain outfalls identified in WV/NPDES Permit Mo. WV0076066 as Outfalls 002 and 003. C-8 samples were taken from all the wells at the Letart Landfill monthly for the first four months and quarterly thereafter. Q Task C: Plume Identification/Groundwater Assessment--determine the vertical and horizontal extent of C-8 impacted groundwater exceeding 1 ug/l or as directed by the GIST at Letart Landfill, This task included an assessment of the C-8 concentration in Ohio River Water in the vicinity of the Letart Landfill. to Sections 52 through 5.4, discussions are presented of the specific activities that were conducted to meet the requirements of the Consent Order, along with the results of the samplingevents. In Section 5.5, the revised site conceptual model is presented that more accurately represents the current environmental setting (geology, hydrology, hydrogeology, groundwater flow and water quality) and current human health and ecological exposure pathways for the conditions at and surrounding the Letart Landfill. 5.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling The groundwater well and water-use survey and samplingactivities conducted within the one-mile radius of the Letart Landfill were completed on February 24,2002. DuPont submitted the results of the one-mile radius survey to the GIST in April, 2002 (DuPont, 2002a). WWlWfl Date Summary - text final Feb. 5,03 37 Wilmlngton.oe ASH02166& EID639901 C-6 Data Summary Report Letart Landfill Table 5.0 summarizes the off-site surveying and sampling program for the one-mile radius, A total of 46 homes were surveyed, and a total of 30 wells were sampled. Eleven of the wells were used as drinking-water sources. Table 5.1 providesdetails for each sample collected including the C-8 concentration measured (ug/1). Bightother wells sampledwere used for non-drinking water and the other 11 wells were unused. No cisterns or springswere sampled. Figure 5.1 shows the locations sampled, regardlessof water use. Each colored circle represents a sampling location, and the color and size of the circle indicate the magnitu4e of the C-8 concentration measured. Small blue circles represent samples having C-8 concentrations less than 0,05 ug/1. Small green circles represent samples having C-8 concentrations ranging from to 0.05 to 1.0 ug/1. The C-8 concentrations measured in all Letart one-mile radius sampleswere ND or NQ, except for one sample collected ftom a well used for drinkingwater that had a C-8 concentration of 0.139 ug/1 and one sample collected from an unused well that had a concentration of 0.636 ug/1- The GIST required that the drinking-water well sample with a C-8 concentration of 0.139 ug/1be re-sampled. However, the resident declined to have the well re-sampled- Based on the very low C-8 concentrations measured when compared to the human health protective screening criteria for water (C-8 SL) of 150 ug/1, the GIST determined that no farther surveying and samplingwas needed. 5.3 Task B: Assessment of Existing roundwater and Surface-water Monitoring Data 5.3.1 Monitoring of C-8 In Groundwater and Surface Water at Letart Landfill Groundwater Monitoring The Consent Order required that all monitoring wells at Letart Landfill be sampled for C-8. Monthly C-8 sampling of groundwater began in December 2001 and quarterly sampling began in May 2002. Table 5-2 provides a list of the monitoring wells included in the groundwater monitoring program for Letart Landfill. Well construction data and groundwater elevation data also are provided in this table. At the time monitoring started, 13 monitoring wells existed at Letart Landfill. Another five wells were installed during 3Q02 as part of the C-8 plume delineation work. These wells were included in the monitoring program that began in 4Q02. Figure 5.2 shows the location of the monitoring wells- Table 5.3 presents the 0-8 concentrations measured in these monitoring wells, including C-8 data generated prior to the issuingof me Consent Order. The most recent data are listed first for each well. The water-bearing units at the Letart Landfill are named from ground surface to depth as the A-Zone through the F-Zone, with the A-Zone being the shallowest and F-Zone being the deepest. Groundwater in the A-Zone, the uppermost water-bearing unit, is monitored through three wells, LMW-1, LMW-7, and LMW-8. These three wells are located along the northwestern edgeof the landfill cell. C-8 concentrations in LLMW-1, LMW-7, and LMW-8 have ranged from 0.1 to 30,500 ug/1. WWK.C-8 Data Summary -text final Feb. 5,03 38 Wilrrtngton, DE ASH021670 EID639902 C-apala Summary Report_______________ _________ _'__.,.._l^artLand!i!l. Ground-water in the next lower water-bearing unit, the B-Zone, is not monitored because this zone is not laterally continuous at the site. Groundwater for the next lower water-bearing unit, the C-Zone, is monitored through LMW-3 and LMW-5A. C-8 concentrations in LMW-3 and LMW-5A ranged from NQ to 2,270 ug/1and from 0.8 to 112 ug/l, respectively. Note that in the grpundwater elevations measured for LMW-5A (see Table 5.2) have always been at depthslower than the bottom of the screen indicating that this well has been essentiallydry throughout the period it has been monitored. Groundwater sampled from this well and analyzed for C-8 may not be representative of the C-8 concentrations in the C-Zone. Groundwater in the D/E-Zone, the next lower water-bearing unit, is monitored through LMW-3A, -4, -SB, -12, -13A, and --14A. C-8 concentrations in LMW-3A and 13A ranged from 60.3 to 510 ug/l. C-8 concentrations measured in LMW-4, -SB and -14A ranged from 172 to 3,060 ug/l. LMW-12 was dry duringthe 4Q02 sampling event. Groundwater in the F-Zone, the underlying significant aquifer, is monitored by LMW-2A, LMW-6, LMW.10, LMW-l 1, LMW-13B, and LMW-14B. C-8 .concentrations measured in 1MW-10, LMW-l 1, and LMW-13B have always been less than 1 ug/l. Concentrations of C-8 in LMW-6 ranged from 9:4 to 30 ug/l. C-8 concentrations m LMW-2A and-14B ranged from 50 to 990 ug/l. An additional sandstone and siltstone zone, located under the P-Zone is monitored by LMW-9. The C-8 concentrations measured in LMW-9 ranged from 0.2 to 0.907 ug/l. Table 5.2 shows that groundwater elevations in this well have consistently been below the bottom of the screen, indicating that this well has essentially been dry during the periodthat is has been monitored, m addition, LMW-9 typically runs dry during sampling and takes days to recharge. Therefore, C>8 concentrations measured in this well (0.2 to 0.907 tig/I) may not be representative of groundwater quality in this zone. The next groundwater sampling event at the Letart Landfill is scheduled for the first quarter 2003. Surface-water Monitoring The Consent Order identified two outfalls at Letart Landfill (regulated by WV/NPDES Permit No. WV0076066) that required monthly C-8 sampling to be performed. Outfalls 002 and 003. Outfall 002 collects leachate and stonnwaternmofffrom the landfill. Outfall 002 then dischargesto a small wet-weather stream at the toe of the landfillOutfall 003 collects stoimwater nmoff. Monthly sampling of these two outfalls began in December 2001. DuPont also is sampling surface-water samples at selected other locations, including Stonnwater Runoff, Rt 33 Stream, Brinkers Run and Cap Runoff. Figures 5.2 and 5.3 sho^r the locations of the six surface-water samplingpoints. Table 5.4 summarizes me C-8 concentrations measured in the outfalls, including C-8 data generated prior to the issuing of the Consent Order. The most recent data are listed first for each outfall. Outfall 002 collects landfill teachate. C-8 concentrations at this outfall have ranged from 4.52 to 3,240 ug/l. Using the 14 ($ee Table 5.4) C-8 results for samples collected after the landfill cap was installed in April 2001, the range is smaller, from 4.52 to 2,050 ug/l. The C-8 concentrations in this leachate have been highlyvariable since the landfill cap WWK-C-8 Date Summary - taxt final Feb. 5.03 39 WIWngton> DE ASH021671 EID639&03 ___ c-8 paia Summary Report Letart Landfill _ _________ was installed. Cap RunoffC-8 concentrations ranged from 65-1 to 371 ug/1. The Stomiwater Runoff sample had a concentration of 50.9 ug/1. The Rt. 33 Stream, Outfall 003, and Blinker's Run samples' C-8 concentrations ranged from 0.0612 to 3.92 ug/1- Outfall samplingfor December 2002 has been completed and the monitoringreport will be issued to the GIST in February 2003. Outfall samplingfor January 2003 has been completed,but the C-8 results have not yet been validated. The next monthly outfall sampling event is scheduled for February 2003. .4 Task C: Plume Identification/Groundwater Assessment Based on the data gaps identified in the Compilation of Historical C-8 Data Report (DuPontt 2002b), the C-8 Plume Identification/Groundwater Assessment Work Plan was developed and submitted to the GIST (DuPont, 2002e). This work plan identified specific activities recommended to fill the data gaps. In the following sections, each of ?'* the activities recommended'in the C-8 plume delineation work plan are summarized. ,i Details of the activity status and the data acquired are then presented, to addition. Task C included an assessment of the C-8 concentrations in Ohio River Water in the vicinity of the Letart Landfill, and these results also are presented. 5.4.1 C-8 Monitoring in Groundwater and Surface Water at Letart Landfill The delineation work plan recommended continuing to monitor C-8 in groundwater in the overburden and in the underlying bedrock aquifer (utilizing the newly installed monitoring wells), and in surface water at existing locations identified in the Consent Order. The results of continued monitoring ofgrouttdwater and surface water are presented in Section 5.3.1. Monitoring of C-8 in groundwater continues on a quarterly basis, while surface-water monitoring of C-8 is conducted on a monthly basis. 5.4.2 Surface-water Field Reconnaissance at the Letart Landfill Conducting field reconnaissance to identify additional surface-water features located at the Letart Landfill and sampling surface water from new locations identified during this effort was a C-8 plume delineation recommended activity. Field reconnaissance was perfbnned and no new surface-water features were identified. Hl^ 5.4.3 Installation of New Wells at Letart Landfill The installation of three additional well clusters (overburden and bedrock) was proposed in the C-8 plume delineation work plan to characterize the bedrock under the Letart Landfill, to further delineate C-8 concentrations in groundwater and to evaluate groundwater flow direction. One bedrock well, LMW-12, and two well clusters, LMW-13A and LMW-13B and LMW-14A and LMW-14B, and were installed during 3002. At LMW-12, no overburden was encountered. Figure 5.2 shows the locations of all monitoring wells at the Letart Landfill includingthe locations of the newly installed monitoring wells. Well construction diagrams for the new wells, are provided in Appendix C. WWK-C-B Date Summary - texl final Feb. 5, 03 40 Wllfningtort,DE ASB023L672 EID63&904 C-8 Data Summary Report Letart Landfill Data from the geologicallogs For the five wells installed in 3Q02 support the previous interpretation of subsurface conditions at the site. Clay and weathered bedrock (shale, sandstone and/or sillstone) Is underlain by bedrock, consisting of alternatinglayers of shale and sandstone, OT siltstone or both. The A-Zone throughthe F-Zone and one additional water-bearing zone, under the F-Zone, were identified. The B-Zone, which exists in the northern areas, thins out toward the south while D/E-Zone exists in the south and thins out to the north. Overall, the new geologicdata confirmed that the lithotogic units dip slightly toward, the south. The new geologicaldata were used to refine the geologicinterpretationused for the revised SCM, which is presentedin detail in Section 5.5.1. 5.4.4 Letart Landfill Site Conceptual Model Refinement The final recommended activity for the Letart Landfill was the integrationof all the new data gatheredduring completion of Tasks A, B, and C into a revised SCM. This activity was completed, and the revised SCM is presentedin Section 5.5. 5.4.5 Ohio River Water Sampling Near Letart Landfill s a m p l i n g Adjacent to the Letart Landfill, Ohio River water also was sampledto measure the C-8 concentrations. Two locations were sampled. These sampling locations are shown in Figure 5.4. One sampling location was positioned in the river near the point where the ravine originatingat the landfill discharges surface water into the river. The other point was located approximately 1,000 feet downstream of the first location. All sampleswere collected near the shoreline (approximately100 feet east of the shoreline). Dip and mid-column samples were collected at both locations. In total, five river-water sampleswere collected, including one duplicatesample. The Ohio River water C-8 results for samples collected near the Letart Landfill are presented at the bottom of Table 3.11 and are shown in Figure 5A C-8 concentrations in these five samples ranged from 0.0971 to 0.128 ug/1. 5.5 Revised Site Conceptual Model The revised SCM better represents the current environmental setting (geology, hydrology, hydrogeology, groundwater flow, and water quality) and current human health and ecological exposure pathways for the conditions at and surrounding the Letart Landfill. The following sections present the revised SCM in detail. 5.5.1 Current Environmental Setting Geology At the time Consent Order was issued, 13 monitoring wells existed at Letart Landfill and monitored the water-bearing zones identified at the Letart Landfill, that are labeled as the A-Zone through P-Zone. Another five wells were installed during 3Q02 as part of the C-8 plume delineation work to better characterize the bedrock under the Letart Landfill, 41 WWK-08 Data Summaof - text final Feb. 5.03 Wilmlngton, DE ASH023L673 EID639&05 c-s Date summary Report_______________________Letart Landfill to further delineate C-8 concentrations in groundwater, and to evaluate groundwater flow direction. The locations of four cross-section? developed for the Letart Landfill are shown in Figure 5.5. Two cross-sections, A-A* and B-B\ were presentedin the Compilation of Historical Data Report (DuPont. 2002b) and are shown in Figures 5,6 and 5.7, respectively. Figure 5.8 and 5.9, are new cross-sections, which starts in the north and runs south, showingthe geological data obtained ftom the newly installed monitoring wells. The Letart Landfill is situated on a heavily dissected plateau consistingof several steep V-shaped valleys. Residual soil covers most landfill areas. In general, the soil at (he site has been described as residual in nature, consisting primarily of heavy clays derived from the weathering of bedrock. At most landfill areas, the clay is less than 10 feet thick, with a maximum thickness of 20.5 feet. The underlying bedrock at the Letart Landfill consists ofinterbedded red and varicolored sandy or calcareous shale, and gray, green, and brown sandstone and/or siltstone of the Permian age Dunlcard Group. Six stratigraphicwater-bearing zones that were designated as the A-Zone throughF-Zone, with the A-Zone beingthe shallowest zone and the F-Zone the deepest. These zones are identified on the cross-sections. These zones consist of massive, very fine to fine grained crystallinesandstone and/or siltstone with occasional shale lenses. The A-Zone through the F-Zone are separatedby locally continuous shale units that are generally 10 feet or greater in thickness. The B-Zone through the D/E-Zone are laterally discontinuous. The B-Zone and the C-Zone are a single'zone in the far north and separate into two distinct zones in the central area. The B-Zone thins out and is missing from logs from the southern area. D-Zone is an isolated unit in the northern area. This unit joins up with E-Zone in the central area. In the southern area, the D-Zone and the B-Zone are a single zone. The A-Zone and the F-Zone are laterally continuous. The A-Zone and the C-Zone outcrop in the valley walls, while the D/E-Zone outcrops along the Ohio River near the southern end of the landfill- The F-Zone likely outcrops in the riverbank of the Ohio River. The logs for LMW-9, LMW-5A, and LMW-5B were re-examined during construction of new cross-sections and are now believed to be screeningother zones. LMW-9 is now interpreted to be screened in a sandstone zone lower than the F-Zone. Because there is only one well in this newly identified zone, it is not clear if (his zone is laterally continuous. LMW-5B previously thought to be monitoring the F-Zone, is now believed to be screened in the D/E-Zone. Well LMW-5A, previously interpreted as monitoring the D/E-Zone, is now interpreted to be monitoring the C-Zone. Hydrology, Hydrogeology and roundwater Flow Hydrology The Letart Landfill engineered cap system prevents surface water from contacting landfilled materials. Precipitation falling on the engineered cap system takes one of two paths. It may infiltrate downward through the vegetated soil and encounter the impenneable geoxnembraneand then flow laterally downslope on top of the geomembrane. Alternatively, precipitation may flow via overland flow on top of the vegetative layer downslope. In either situation, this surface water does not contact me WWK.08 Date Summary ~ text final Feb. S, 03 42 Wilralngton, DE ASH021674 EID639&06 C-8 Data Summaly Report Letart Landfill landfilled materials and rni grates downslope toward drainage ditches constructed in or adjacent to the cap system. Precipitation falling on the northwest side of the upper part of the cap flows downslopetoward the southwest, away from the landfill, into a drainage ditch that flows to a sediment trap near LMW-6. Precipitationfalling on the remaining portionsof the cap Hows downslope and toward the south in drainage ditches. Hydrogeotogy Hydraulic conductivity testing [i.e., slug tests (A-Zone) and borehole packer tests (C-Zone, D/E-Zone, and F-Zone)] of the bedrock zones indicates that these zones display low hydraulic conductivity (Tetra Tech Richardson, 1990). The A-Zone hydraulic conductivity is low, ranging from Iff4 cm/sec to less than Iff5 cm/sec. (There are no wells monitoringihe B-Zone; therefore, it was not tested.) The C-Zone and the P-Zone have very low hydraulicconductivities ranging from 10* cm/sec to less than 10' 10'5 cm/sec. The D/E-Zone hydraulicconductivities also are very low and range from cm/sec to 10'3 cm/sec. The low hydraulic conductivities can be attributed to the very line-grained nature of the water-bearing units. In addition, many sandstone units m the region typicallydisplayeffective porosityas low as 1 percent This low porosityresults from pore space being filled in by authigenic minerals (e.g. kaolinite) sometime after original sediment deposition. The F-Zone has oeen designatedthe "underlying significant aquifer" as defined by the West Virginia Solid Waste Management Regulations because it is laterally continuous under the landfill and is thought to be hydraulicallyconnected to the Ohio River south of the landfill. The P-Zone groundwater average linear velocities were calculated for flow from the north to the southwest and from the north to the southeast (DuPont, 2000). These values are relatively low, 0.01 and 0,003 ft/day, respectively. The low velocities calculated in the F-Zone indicate that groundwater flow beneath the landfill is very slow, attributable to the low hydraulic conductivity present in the F-Zone and all the overlying units as well. Low vertical hydraulic conductivities in the overlying shallow zones limit infiltration and recharge down to the P-Zone. The saturated thickness of F-Zone is higher in the upgradient wells (LMW-2A and LMW-11) and is lower in the downgradient wells (LMW-6, LMW-13B, LMW-14B, and LMW-10). la many instances, the monitoring wells at the landfill cannot be sampled until 48 hours (or longer) after purging, when a sufficient quantity of groundwater has recovered in the well screen interval. LMW-10 appears to essentiallybe dry (see Table 5.2). Groundwater Flow Groundwater elevation contour maps for the significant underlying aquifer (F-Zone) were prepared as required by the WV/NPDES Permit No. WV0076538. Table 5.2 provides groundwater elevation data for wells in the monitoring program. Figure 5.10 presents a groundwater elevation map for 4Q02 data from the D/E-Zone. Figure 5.11 presents groundwater elevation map for 4Q02 data from F-Zone. Note that Figure 5.11 has been revised compared to the groundwater elevation map for 4Q02 that was provided in the 4Q02 groundwater and surface-water monitoring report. Figure 5.11 now includes the 43 WWK-C-8 Data Summary - text final Feb. 5. CO WIminaton, DE ASH021675 EID639907 C-8 Data Summary Report __ ____ ______ _____.__.. _ .... _ ^6tart ^O^JJ!1. new wells that monitor the F-Zone. LMW-9, which is screened below the F-Zone, has been removed. Groundwater flow in both the D/E-Zone and the F-Zone is basically from the north toward the south. For Figure 5.10, the 4Q02 groundwater elevation contour map for the D/B-Zone, two wells that monitor this zone were not used. The D/E-Zone becomes quite complicatedin the southern portion of the landfill area. In the very northern areas, the D/B-Zone does not exist. In the north-central portion of the landfill area, the D/E-Zone appears as a singlelifhological unit. In the south-central part, the D/E-Zone splitsinto a thimier upper unit and a thicker lower unit. At the toe of the landfill are three wells that monitor the D/B Zone, two are screened in the upper unit (LMW-3A and LMW-4) and one (LMW-5B) is screened in the lower unit. Although these wells are relatively close together, the groundwater elevations measured in these three wells differ significantly. Therefore, LMW-3A and LMW-4 were not used in constructingthe groundwater elevation map because the elevations that were observed in these wells were not thought to be representativeof overall groundwater flow within this zone. m general, ground water flow in this zone is ftom the north toward the south. Figure 5.11 presents the 4Q02 groundwater elevation map for the F-Zone. In this zone, groundwater also flows from the north. However, in the southern portion of the landfill, groundwatw flow starts to be perpendicular the Ohio River and flows toward the southeast. For this groundwater elevation map, the water level measured for LMW-10 was not used. Table 5.2 shows that water levels in this well have consistently been within 1 foot of the bottom of (he screen, and sampling this well has been difficult because the well frequently goes dry during purging and is very slow to recharge. In addition, water levels in this well are much lower than expected compared to adjacent wells. The location and limited number of monitoring wells within the A-Zone and the C-Zone prevents determination of groundwater flow directions within these zones. However, ' elevations measured in the monitoring wells indicate a downward vertical gradient within thesite groundwater system..,.............................._......... ......... ............ Rapid decreases m the observed volume of water dischargingfrom the leachate collection system in 2001 indicate that groundwater flow under the landfill is being greatly reduced in response to the installation of the engineered cap system. Water Quality Groundwater Quality Table 5.3 presents all historical analysis available for C-8 from monitoring wells at the Letart Landfill. Data in this table are presented and discussed by zone. Figure 5,7 shows a cross-section through the southern end of the Letart Landfill. Prior to the filling of (he valley, this cross-section shows that the A-Zone, the B-Zone, and the C-Zone most likely outcropped in the western valley wall, the C-Zone outcropped in the eastern valley wall, and the D/E-Zone likely outcropped in the valley floor. Further up the valley toward the north, it is likely that the A-Zone, the B-Zone, and the C-Zone outcrop on both the western and eastern sides of the valley. The landfill is an unlined WWK-W Date Summary -- text teal Feb. 5,03 44 Wllmington.DE ASH021676 EID639908 08 Date Summary Report ____ ___ Letart Landfill landfill. This means that C-8 impacted water migrating through the landfilled material prior to the installation of the engineered cap may have been able to migrate directly into the C-Zone, then the B-Zone, then the A-Zone as the landfill was filled. The groundwater elevations also indicate that there is an overall downward gradient froni the A-Zone to the F-Zone. This downward gradient also would help transport C-8 downward from one zone to the next lower zone. Groundwater flow within the zones also would move C-8 around within the individual zone. However, the installation of the engineered cap will minimize the amount of precipitationable to infiltrate into the. landfilled material. The concentration of C-8 in the various wells in the different zones indicated that the C-8 impact is the greatest at differing locations within the zones, which is expectedgiven that the C-8 concentration in the landfilled materials was most likely highly variable. In the A-Zone, IMW-1 shows the highest concentrations; and, in general, the C-8 concentrations appear to be increasing over time for all three wells. In the C-Zone, C-8 . concentrations have been higher in LMW-3 than in LMW-5A. In the D/E-Zone, the highestC-8 concentrations are found in LMW-4 and LMW-5B, both located at the toe of the landfill, h the F-Zone, LMW-2A, which is located near the northern edge of the landfill, has the highest C-8 concentrations. In LMW-9, which monitors a zone lower than the F-Zone, C-8 concentrations have always been less than 1 ug/l. C-8 concentrations in groundwater from 28 residential wells located within a one-mile radius of the Letart Landfill have concentrations that are ND or NQ (DuPont, 2002a). Two groundwater samples had higher values, 0.139 and 0.636 ug/l. These data indicate that although the groundwater in the zones under and near the landfill cell has higher levels of C-8, the C-8 impacted groundwater has not migrated far. The 0.139 ug/l sample is located amongst many other samples that had C-8 concentration ofND or NQ. The location of the 0.636 ug/l sample is almost the same location as where the Rt 33 Stream sample is collected. C-8 concentrations in the Rt. 33 Stream sample have ranged from 0,573 to 3.92 ug/l. It i$ possible that this well is in communication with C-8 impacted surface water at this location. The stream that is being sampled does receive surfacewater runofi'from the landfill. The C-8 concentration measured within the One-mile radius are significantly lower that the CATT-established C-8 SL a of 150 ug/l. In the Compilation of Historical Data Report (DuPont, 2002b), the annual loading of C-8 to the Ohio River from C-8 impactedgroundwater at Letart Landfill was calculated. The estimation was based on the assumption that impacted groundwater flows from the A-Zone downward to the P-Zone and ultimately migrates to the Ohio River. The C-8 historical mean for LMW.5B can be used along with the estimated groundwater flux to calculate the C-8 loading to the river. The estimated annual loadingwas I x 10-3 Ib/yr. This calculated mass is reasonable given the low hydraulic conductivities and low average linear velocities observed in the F-zone. This annual loading should result in a very low C-8 concentration in the Ohio River. The annual loading estimation was recalculated using a new historical mean value for the C-8 concentration in LMW-5B now that more C-8 monitoring data are available. The new mean value is 1,149 ug/l, higher than the previous mean used. Therefore, the revised annual loading estimate is 0.017 Ib/yr, also higher than previously estimated. The revised annual loading also should result in a very low concentration in the Ohio River. The WWK-C-BDataSummaiy-lBXUmal Feb. 5.03 45 Wilmington, DE ASH02167? BID639909 C.8 Data Summary Report Letart Landfill measured 08 concentrations in the Ohio River near the Letart Landfill are indeed low, with the maximum concentration measured being 0.128 ug/1. These concentrations are orders of magnitude lower than the C-8 SL of 150 ug/1and the Aquatic Life Advisory Concentration for C-8 (C-8 ALAC) of 1,360 ug/1. Surface-water Quality Table 5.4 presents the C-8 results for surface-water locations monitored at the Letart Landfill. Samplinglocations. Outfall 002, Cap Runoff, and Stormwater Runoff are associated with leachate from the landfill and have had the highestC-8 concentrations measured in surface water at the Letart Landfill. Cap Runoff and stormwater runoffhave had C.8 concentrations ranging from 50.9 to 317 ug/1. Outfall 002, which discharges leachate and stormwater runoff, has had highly variable C-8 concentrations (hat have ranged from 4.52 to 2,050 ug/1since the installation of the landfill cap. Outfall 003, which discharges stormwater runoff, has been dry or has had C-8 concentration lower than 0.4 ug/1. The Brmker Run sample, which was collected from a stormwater drainage diteh, had a very low C-8 concentation, 0.0612 ug/1. Stormwater runoff from the northern part of the landfill flows down the stormwater drainage ditch, off the property and into Blinker's Run. Brinker's Run discharges into a pond that is located off the north side of die landfill property. The Rt. 33 Stream sampleis collected at the point where Brinker's Run enters the pond. The C'8 concentrations for the Rt 33 Stream samples have ranged from 0.573 to 3.92 ug/1. The pond then dischargesto the Ohio River. Other than Outfall 002 and Cap Rnnoff samples, all the surface-water samples for the Letart Landfill are less than the drinking water and the C-8 ALAC (WVDEP, 2002; MenzieCura & Associates, 2002). 5.S.2 Current Human Health and Ecological Exposure Pathways The main objective of the Consent Order was to determine whether there has been an impact on human health and the environment as a result of releases of C-8 to the environment from DuPont operations at me Washington Works facility and the associated landfills (Local, Letart, and Dry Run). Therefore, human health and ecological exposure pathways both on-site (at (he Letart Landfill) and off-site (adjacent to the Letart Landfill) must be considered. The human health and ecological exposure pathway sections below describe the potential exposure routes for human and ecological receptors 0x1- and off.site. Potential exposure routes were evaluated and classified as complete or incomplete. Table 5.5 summarizes the human health and ecological exposure pathway evaluation for the Letart Landfill. To be conservative, for each complete exposure pathway, the maximum C-8 concentration measured in (he C-8 impacted media is compared to the C-8 SL, regardlessof media type. On-Slte Human Health and Ecological Exposure Pathways Current Environmental Setting This section describes the potential exposure routes for human and ecological receptors that are found at the Letart Landfill. On-site human receptors include authorized facility workers and facility contractors. Ecological receptors include animals living within the 46 WWK-C-8 Data Summary - text linat Feb. 5,03 Wilniington, OE ASH021678 EID63&910 C-8 Data Summary Report Letart Landfill landfill boundaries. Potential exposure routes were evaluated and classified as complete or incomplete. The Letart Landfill closure was completed in April 2001 with the installation of an engineered cap system. The cap system drainage controls were designedto convey the runofifrom the landfill cap to a designateddischarge point and to eliminate the potential for runoff-related erosion of the cap. In addition, the landfill cap is required to be inspectedat least quarterly (permit requirement C.12.A) for evidence of erosion as part of the landfill's Stonnwater Pollution Prevention Plan. The engineeredcap system prevents human and ecological contact with the landfilled materials and soils that may have been impacted by C-8. Contact with C-8 containing landfflled materials and soils is considered an incomplete exposure pathway to human and ecological receptors. The Letart Landfill engineeredcap system also prevents surface water from contacting landfilled materials. Surface water flows toward drainage ditches constructed in the cap system and is dischargedat fhe southern edge of the landfill. Because this surface water does not contact the landfilled materials, it is not impacted by C-8. However, leachate dischargingfrom the leachate collection system is piped to Outfall 002 (leachate basin), where it mixes with stonnwater runoff. Outfall 002 enters a small, wet-weather stream fhat Bows approximately 400 feet before it dischargesto the Ohio River. However, exposure is limited because of the remote location of the landfill, the very steep terrain, and the wet-weather nature of the stream. In addition, fencing limits access to the area. Further, the use of health and safety plans, standard operatingprocedures, and personal protective equipment also limit exposure. The highest C-8 concentration measured in leachate since the installation of the landfill cap was 2,050 ug/1. The highest C-8 concentration measured in the Ohio River adjacent to where this wet-weather stream enters the river wa$ 0.128 ug/1. The D/E-Zone and the F-Zone exist at elevations lower than the leachate collection system. Groundwater flowing from these zones to the south discharges to the Ohio River. Contact with this water is limited to the areas where these zones may outcrop on the valley walls. However, in general, groundwater flows downslope within the shallow soil, colluvium, and fractured rocks of the valley walls and would only be exposed at the surface if seeps exist. Field reconnaissance did not identify any seeps in the valley walls; therefore, this exposure pathway for human and ecological receptors is incomplete. Off-site Human Health and Ecological Exposure Pathways Off-site human receptors include residents using the water sources sampled during the groundwater well and water-use survey. Ecological receptors include livestock using the water sources sampled during the groundwater well and water-use survey. West Virginia One-Mile Radius Groundwater and Surface Water Direct exposure to C-8 impacted surface water and groundwater is an incomplete pathway in situations where the water source is not used. The pathway is considered to be a complete pathway in situations where the water source is used, but not for drinkingwater purposes, although the exposure is considered to be minimal because the water is not ingested. The highestC-8 concentration in a non-drinking-water sample was NO, well below the C-8 SL of 150 ug/1. The pathway is considered to be complete if the well WWK-C-8 Data Suti)inaiy - text Hnal Feb. 5,03 47 Wllmlnglon. DE ASH021679 EID63&&11 C-8 Data Summary Report (.etart Landfill is used for drinking-water purposes. The highest C-8 concentration measured in drinking water was 0.139 ug/1, significantly lower than the CATT-established C-8 SL of 150 ug/1 (WVDEP, 2002). Therefore, even though the pathway is complete, it also is limited due to the low C-8 concentrations measured. 5.6 Letart Landfill Summary Many different activities have been conducted at and around the Letart Landfill in order to determine whether there has been an impafcrot monthheumlaanndfhiella. ltThhaenCd -t8hecoenncveirnotnramtieonnt ians a result of releases groundwater and of C-8 to the environment surface water from many sources (on-site, off-site, monitoring well$, production wells, private wells, and Ohio River water) was measured. Based on all of the data evaluated for the Letart Landfill, the following observation were made: Q The current exposure pathways are incomplete for human and ecological receptors contact with the following C-8 impactedmedia: On-site landfilled materials On-site soil On-site groundwater 0 Human and ecological receptors contact with C-8 impacted surface water and leachate (Cap Runoff and Outlet 002) dischargingto the wet-weather stream at the toe of the landfill are currently complete exposure pathways. The highestC-8 concentrations measured at these locations are 371 and 2,050 ug/1,respectively. However, exposure is Uniited because of the remote location of the landfill, the very steep terrain, and the wet-weather nature of the stream. In addition, fencing limits access to the area. Further, the use of health and safety plans, standard operating procedures, and personal protective equipment also limit exposure. 0 Current off-site exposure pathways for human and ecological receptors that are complete but limited, due to the very low C-8 concentration measured, include residential drinking and non-drinking-water sources and river water. For the drinking and oon-drinldng-water sources, the highest C-8 concentrations measured were 0.139 and NQ, respectively, which are well below the C-8 SL of ISO og/1(WVDBP, 2002). The highest C-8 concentration measured in Ohio River water is 0.128 ug/1, well below the C-8 SL of 150 ug/1and the 1360 ug/1C-8 ALAC developedby the CATT (Menzie-Cura & Associates, 2002). 0 Groundwater flow in the site significant aquifer under the landfill is toward the southwest and the Ohio Rivw. C-8 impacted groundwater from the water-bearing zones at Letart Landfill ultimately flows into the Ohio River. 0 Evaluation of the groundwater flow directions at the landfill and of the Letart onemile radius C-8 results shows that C-8 impactedgroundwater is not migrating toward off-site residences. Q The revised C-8 annual loading estimate from groundwater indicates a very low C-8 concentration in the Ohio River from the Letart Landfill. This low estimated concentration is supported by C-8 concentrations measured in the Ohio River 48 WWK-C-8 Data Summary - tort final Feb. 5.03 WllfflhBton. DE ASH021680 BID639912 C-6 Data Summary Report Landfill -_______________________________Letart (0.128 ug/1)that are well below the C-8 SL and the C-8 ALAC that were determined by the CATT (WVDBP, 2002; Menzie-Cura & Associates, 2002). Q The transport pathway of C-8 at the Letart Landfill is believed to be via water transport from C-8 containing landfill materials. Q Air emission of C-.8 as a migration pathway is not possiblebecause there are no air emissions at the Letart Landfill. In addition, the Letart Landfill is too far away from the WashingtonWorks facility to be impactedby C-8 containing air emissions emanating from the facility. WWK-C-B Data Summary - text dual Feb. 5,03 Wllmlngton. DE 49 ASH021681 EID639913 C-6 Date Summary Report ________BEy^"111^-3"^ 6.0 DRY RUN LANDFILL 6.1 Introduction The Dry Run Landfill is located west of the town ofLubeck, in Wood County, West Virginia, about eight miles southwest of the WashingtonWorks facility and the Local Landfill (seeFigure 6.0). The landfill covers approximately17 acres of a 535-acre parcel of land owned by DuPont. The landfill was constructed within the drainagebasin of Dry Run, a tributary of the North Fork of Lee Creek, which is a tributary of the Ohio River. The landfill began operation in 1986 and the central portion is still active and operates under WV7NPDES Permit No. WV 0076244. The upper portion of the landfill is closed and is covered with a soil and vegetative cover. The lower portionof the landfill also is closed and is covered by a engineered landfill cap. Consent Order required tasks to be conducted at or immediately adjacentto the Dry Run Landfill included the following: Q Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling- conduct a distance-phased groundwater well and water-use survey identifying and sampling all groundwater wells, springs, and cisterns within a one.mile (and possibly two- and three- mile) radial distance of the facility and the Dry Run Landfill. Q Task B: Assessment of Existing Groundwater and Surface Water Monitoring Data--conduct monthly sampling for C-8 will be performedat Dry Run Landfill \ at outfalls identified in WV/NPDES Permit No. WV0076244 as Outfalls 001, 003, and 004. C-8 samples were to be taken from all (he wells at the Dry Run Landfill monthly for the first four months and quarterly thereafter. Q Task C: Plume Identification/Groundwater Assessment--determine the vertical and horizontal extent of C-8 impacted groundwaler exceeding 1 ug/1or as directed by the GIST at Dry Run Landfill. h Sections 6.2 through 6.4, discussions of the specific activities conducted to meet the requirwnerrts of the Consent Order are discussed along with the new data generated during these activities, to Section 6.5, the revised site conceptual model that better represents the current environmental setting (geology, hydrology, bydrogeology, groundwater flow, and water quality) and current human health and ecological exposure pathways for the conditions at and surrounding the Dry Run Landfill is presented. 6.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling The groundwater well and water-use survey and sampling within the one-mile radius of the Dry Rim Landfill were completed on February 28,2002. DuPont submitted the results of the one-mile radius survey to the GIST in April, 2002 (DuPont, 2002a). WWK-C-8 Dala Summary - text final Feb. 5. 03 Wilniington.OE 50 ASB021682 EID63&914 C-B Date Summary Run Landffll Report___________________Pry Table 6.0 summarizes the off-site surveying and samplingprogram for the one-mile radius. A total of 64 homes were surveyed, and a total of 53 water sources (wells, cisterns and springs)were sampled. Thirteen wells, one cistern, and one springsampled were used as drinking-water sources. Table 6.1 provides details for each sample collected including the C-8 concentration measured (ug/1). Figure 6.1 shows the locations of all samples collected, regardlessof water use. Each colored circle represents a samplinglocation, and the color and size of the circle indicate the magnitude of the C-8 concentration measured. Small blue circles represent sampleshaving C-8 concentrations less than 0.05 ug/1. Small green circles represent sampleshaving C-8 concentrations ranging from to 0.05 to 1.0 ug/1. The C-8 concentrations measured in all the Dry Run Landfill one-mile radius samples were less than 1.0 ug/1. The highest C-8 concentrations measured for unused and nondrinking-water sources were 0.974 and 0.54 ug/1. Seven of the 15 drinking-water samples were ND orNQ, and the range of C-8 concentrations in the other eight drinkingwater samples was between 0.0505 and 0.339 ug/1. Based on the very low C-8 concentrations measured when compared to the human health protective screening criteria for water (C-8 SL) of 150 ug/1, the GIST determined that no further surveying and sampling was needed. However, the GIST did require resamplingof the eight drinkingwater sources with measurable concentrations of C-8. Residents of five of the eight drinking-water sources declined to have their water sources resampled. Resampling of the three drinking-water sources was completed in April 2002. C-8 concentrations ranged from NQ to 0.422 ug/1in these samples (DuPont, 2002h). In addition, a surface-water sample was taken from the Lee Creek near the Graham residence, which is located a few miles west-northwest outside of the Dry Run one-mile radius. This sample was taken to evaluate C-8 quality in the Lee Creek before it discharges to the Ohio River. The Dry Run creek, which begins at the toe of the landfill, discharges surface water to the Lee Creek. The C-8 concentration measured was 028 ug/1(DuPont, 2002h). At this same residence, a drinking-water well and a spring used for non-drinking-water purposes also were sampled and analyzed for C-8. The C-8 concentrations measured in these water sources were ND and 0.33 lug/I, respectively. 6.3 Task B; Assessment of Existing Oroundwater and Surface-water Monitoring Data 6.3.1 Monitoring of C.8 in Qrountlwater and Surface Water at Dry Run Landfill Groundwater Monitoring The Consent Order required that all monitoring wells at Dry Run Landfill be sampledfor C-8. Monthly C-8 samplingofgroundwaler began in December 2001, and quarterly sampling began in May 2002. Table 6.2 provides a list of the monitoring wells included in the groimdwater monitoring program for Dry Run Landfill. Well construction data and groundwater elevation data also are provided in this table. At the time monitoring started, eight monitoring wells were installed at the Dry Rim Landfill. Another seven wells were installed during 3Q02 as part of the C-8 plume delineation work plan, and these new wells were included in the monitoring program starting in 4Q02 (DuPont, 2002k). WWK-C-8 Date Summaly - text And Feb. 5,03 51 Wilmlnaton, DE ASH021683 BID639915 C-8 Data Summary Run LanCJftH Report______________________,,__________Pry Figure 6.2 shows the location of the monitoring wells. Table 6.3 presents the C-8 concentrations measured in these monitoring wells, including C-8 data acquired prior to the issuingof the Consent Order. The most recent data are listed first for each well. The water-bearing units at Dry Run are named from ground surface to depthas the Overburden, and the A-Zone, the B-Zone, and the C-Zone. Wells monitoring the overburden include DRMW-6A, DRMW-12A, DRMW-12B, DRMW-13A, and DRMW-21A. DRMW-13A has $hown the highestC-8 concentrations m overburden, rangingfrom 0.07 to 15 Ug/1. This well is located at the toe of the landfill, DRMW-6A has shown a C-8 concentration range of0.096tol.24ug/!. DRMW-42A, DRMW-I2B, and DRMW-21A have had much lower C8 concentrations, ranging from ND to 5.4 ug/1. Wells monitoringthe A-Zone include DRMW-16B, DRMW-17B, DRMW-18B, DRMW-19B, and DRMW-20B. DRWM-14 is a continuous open hole; therefore, effectively monitors all water-bearing sandstone and siltstone units above the A-Zone as well as the A-Zone. All of these wells are new wells, except DRMW-14, and have only been sampledone time. C-8 concentrations in these new wells has ranged from ND to 0.155 ug/1. C-8 concentration in DRMW -14 has ranged from <0.1 to 2,5 ug/1. Wells monitoringthe B.Zone include DRMW-12, DRMW-13, and DRMW-15. DRMW-12 has shown the lowest C-8 concentrations, ranging from <0.1 to 0.16. DRMW-I5 has had higher C-8 concentrations ranging from 0,263 to 5.0 ug/1. DRMW-13, which is located at the toe of the landfill, has had the highest concentration of C-8, ranging from 3.6 to 20,9 ug/1. Only one well monitors the C-Zone, DRMW-21B. This is a new well that has only been sampledonce, and the C-8 concentration measured was NQ. The next groundwater sampling event for the facility is scheduled for the first quarter 2003. . Surface-water and Leachate Monitoring The Consent Order identified three outfalls at the Dry Run Landfill (regulated by WWNPDBS Permit No. WV0076244) where monthly C-8 sampling was to be perfonned, Outfalls 001,003, and 004. (Outfall 002 is a required outfall sampling location as stated in the WV/NPDES permit. However, it was a temporary relocation of Outfall 001 and no longer exists). Outfall 001 collects stormwater and leachate. Outfalls 003 and 004 collect stormwater only. Monthly samplingof these three outfalls began in December 2901. In addition, there are five other locations that are sampled quarterly for C-8. These include Stream Samples-1 (SS-1) and -2 (SS-2), Pond Underdram, Property Boundary, and DR Leachate. The locations of me surface-water and leachate sampling points are shown in Figure 6.2. The Property Boundary sample location is located along the western property boundary where the Dry Run creek crosses over the property boundary (see Figure 6.0). Table 6.4 provides the C-8 concentrations measured in the outfalls and leachate, including C-8 data acquired prior to the issuing of the Consent Order. The most recent data are listed Erst for each outfall. WWK-C-a Data Summary - text final Feb. 5,03 Wllmlngton. DE 52 ASH02l6e4 EIt>639916 ^P c-gpaiaSOTmaiyRepon___________________Dry Run LancffiU Outlet 004 is upgradient and flows into SS-1. SS-1, Outlet 001, Outlet 003, and Pond Underdraw flow into SS-2, which flows ultimately into the Property Boundary sampling point Outlet 004 has had no-flow conditions in 10 of 12 sampling events. In the two events in which samples could be taken, the C-8 concentrations were 0.7 and 158 ug/l, making it difficult to determine a representativeC-8 concentration for this location. SS-1 ha$ shown the lowest C-8 concentrations, ranging from 0.54 to 1.63 ug/l. The C-8 concentrations in Outlet 003 and Property Boundary have been higher, ranging from 0.88 to 39 ug/l, although, Outlet 003 has had no-flow conditions in nine of the 12 sampling events- The Outlet 001, SS-2 and Pond Underdrain samplinglocations have shown C-8 concentrations ranging from 4.6 to 87 ug/l. The DR Leachate samplingpoint, from which leachate is sampled, has shown the highest C-8 concentrations in surface water, ranging &om 27.4 to 704 ug/l. The inactive lower half of the landfill is covered by geotextiles and geomembranes of the leachate collection system. Leachate at the Dry Run Landfill does not dischargeto surface water. Leachate is captured by the leachate collection system at Dry Run and is transported to the Washington Works facility where it is treated. Outfall sampling for December 2002 has been completed, and the monitoringreport will be issued to the GIST in February 2003. Outfall samplingfor January 2003 has been completed, but the C-8 results have not yet been validated. The next monthlyoutfall sampling event is scheduled for February 2003. 6.4 Task C: Plume IdentSflcatIon/Groundwater Assessment Based on the data gaps identified in the Compilation of Historical C-8 Data Report (DuPont, 2002b)> the C-8 Plume Identification/Groundwater Assessment Work Plan was developedand submitted to the GIST (DuPont, 2002e). Included in this work plan were specific activities recommended to fill the data gaps. hi the following sections, each of the activities recommended in the C-8 plume delineation work plan is summarized briefly. Details of the activity status and the data acquiredare then presented. 6.4.1 C-B Monitoring in Groundwater and Surface Water at Dry Run Landfill Continuingto monitor C-8 in groundwater in the overburden and in the underlying bedrock aquifer (utilizing the newly installed monitoringwells), and in surface water at existing locations identified in me Consent Order, was an activity recommended in the C-8 plume delineation work plan. The results of continued monitoring of groundwater and surface water are presented in Section 6.3.1. Monitoring of C-8 in groundwater continues on a quarterly basis, while surface-water monitoring of C-8 is conducted on a monthly basis, fa addition, sampling of Lee Creek, which crosses the site boundary, also was recommended in the C-8 plume delineation work plan. This sample was recommended to evaluate C-8 concentrations further downstream from the landfill than preexisting surface-water monitoring points. The Dry Run creek begins at the toe of the landfill and then dischargesto Lee Creek, which dischargesto the Ohio River. This sample was collected, and the C-8 results are .presented in Section 6.3.1. WWK-C-8 Date Summary - text final Feb. 5,03 53 Wlhiiflgton. 06 ASH021685 EID639917 c^s pate summary Run LandfH[ Repon______________Dry 6.4.2 Surface-water Field Reconnaissance at the Dry Run Landfill Conducting field reconnaissance to identify additional surface-water features located at the Dry Run Landfill and samplingsurface water from new locations identified during this effort was a C-8 plume delineation recommended activity. Field reconnaissance was performed (during droughtconditions) and no new surface-water features were identified beyond those locations that are currently sampled. 6.4.3 Installation of New Wells at Dry Run Landfill Six additional well clusters (overburden and bedrock)were installed as proposedin the C-8 plume delineation work plan to better characterize the bedrock at the Dry Run Landfill, to further delineate C-8 concentrations in groundwater and to re-evaluate groundwater flow direction. During implementation of field activities, overburden was minimal or was dry at most locations; therefore, five bedrock wells and one well cluster were installed. Figure 6.2 shows the locations of all monitoring well at the Dry Run Landfill including the locations of the newly installed monitoring wells. Well construction diagrams for the new wells, are provided in Appendix D. The geological logs for the five bedrock wells and the one well cluster installed in 3Q02 confirm previous interpretations of subsurface conditions at the Dry Run Landfill. Clay, silty clay, or fill material is underlain by bedrock, consisting of alternating layers of sandstone and siltstone separated by layers of shale- Further, the new geologic logs also confirro that the lithologic units are essentially horizontal. New to our geological interpretation is the identification of three individual water-bearing bedrock zones labeled as A-Zone, B-Zone, and C-Zone. These zones are discussed in detail in Section 6.5.1. 6.4.4 Dry Run Site Conceptual Model Refinement The final recommended activity for the Dry Run Landfill was the integrationof all the new data gathered during completion of Tasks A, B, and C into a revised SCM. This activity has been completed, and the revised SCM is presented in the following section. 6.5 Revised Site Conceptual Model The revised SCM ideally should accurately represent the current environmental setting (geology, hydrology, hydrogeology, groundwater flow, and water quality) and current human health and ecological exposure pathways for tiheconditions at and surrounding the Dry Run Landfill The following sections present the revised SCM in detail. 6.5.1 Current Environmental Setting Oeology The locations of four cross-sections developed for the Dry Run Landfill are shown in Figure 6.3. Two cross-sections, A-A* and B-B', were presented in the Compilation of Historical Data Report (DuPont, 2002b). Cross-section A-A' was based on minimal data, This original cross-section has been abandoned, and anew cross-section A-A', which includes many of the new wells installed in 3Q02, was generated. This new cross-section WWK.OB Daa Summaty - text Boat Feb. 5.03 54 Wamington.DE ASH0216Q6 EID639918 C-8 Data Summary Report Dry Run Landfill A-A', which runs northwest to south east along the northeast side of the landfill, is presentedin Figure 6.4. Cross-section B-B\ running north to south across the toe of the landfill, has been modified slightlybut the basic information in the cross-section remain. The modified cross-section B-B' is presented in Figure 6.5. hi addition, cross-sections A-C' and D"B' (see Figures 6.6 and 6.7), which include the new wells, were developed. Cross-section A-C runs from the northwest to the southeast on the southwest side of the landfill. Cross-section D-B' runs across the center of the landfill crossing from the northeast to the southwest. The Dry Run Landfill is situated on a heavily dissected plateau consisting of several steep V-shaped valleys. Residual soil covers most landfill areas. In general, the soil at the site has been described as residual in nature, consistingprimarilyof heavy clays derived from the weathering of shale. A geotechnicflilnvestigation of the overburden underlying the Dry Run Landfill was completedby DuPont (1996). The investigation consisted of advancing soil test borings, test pits, laboratory testing of soil physicalproperties,stability analyses, and settlement analyses. DuPont (1996) determined that the natural residual soil underlying the landfilled materials consisted of stiff to very hard silty clay and clayey silt with occasional rock fragments and a trace of sand. The thickness of this natural soil ranged from 12 to 28 feet in the test boringswithin the landfilled area. In 1989, a monitoring well installation program, performed by Tetra Teeh Richardson toe., indicated similar silty clay and weathered shale overburden. Currently, there are five monitoring wells that monitor the water-bearing overburden (DRMW-6A, DRMW-12A, DRMW-12B, DRMW-13A, and DRMW-21A) at the Dry Run Landfill (see Figures 6,4 through 6.6). Completion depths for these wells range from approximately 12 to 20 feet bgs. The underlying bedrock at the Dry Run Landfill consists ofmter-bedded red and varicolored sandy or calcareous shales, and gray, green, and brown sandstones and/or siltstones of the Permian age Dunkard Group. Based on the new geologicaldata, three separate water-bearing siltstories and/or saridstone units have been identified within the bedrock at Dry Run. These zones are shown on me cross-sections when possible. These are labeled the A-Zone, 1he B-Zone, and the C-Zone, with the A-Zone being the uppermost unit and the C-Zone being the lowest unit bgs. The A-Zone is laterally continuous under most of the landfill area, while the B-Zone is known to be laterally continuous under the toe of the landfill in the northwest. None of the new wells were drilled deep enough to encounter the 0-Zone. The B-Zone was not observed in DRMW-14, the well located furthest to the southeast. However, no additional sandstone or siltstone units were encountered under the A-Zone at the projected elevation of the B-Zone. The C-Zone was only encountered at the farthest northwest location, DRMW-21B. Hydrology, Hydrogeology and Groundwater Plow Hydrology The Dry Run Landfill is situated on a heavily dissected plateau consisting of several steep V-shaped valleys. The Dry Run creek drains the valley in which the landfill is located, 55 WWK-08 Data Summaty - text final Feb. 5.03 Wilmlrigton.DE ASH021687 EID639919  . .-.^ i',lWlia\ C-S Data Summary Report Dry Run Landfill Many small tributaries discharge from the nearby valleys into the Dry Run creek before it joins up with the North Fork of Lee Creek. The installation of landfill cap and a leachate collection system at the Dry Run Landfill encompassingthe inactive lower half of the landfill was completedby Potesta & Associates, Inc. in 1999. Leachate from the landfill dischargesinto a leachate collection sump located northwest of the landfill (see Figure 6.2) throughperforatedpipes buried at the low edge of the fill area. The leachate i$ pumped from the collection sump to a 50,000-gallon collection tank located at the top of the hill. Leachate is pumped from the collection tank to a tanker truck, which is then hauled to the facility for treatment in the wastewater treatment plant. Six surface-water sampling points are located near the toe of the landfill (see Figure 6.2). Four of these six points are man-made monitoring points associated with the leachate collection system and the lower landfill cap. Two points, SS-1 and SS-2, monitor surface water in streams located near the toe of the landfill. Ultimately, all of these surface-water monitoring points discharge into Dry Run creek. Dry Run creek ultimately discharges into Lee Creek. Lee Creek discharges into the Ohio River. Hydrogeology Groundwater occurs in the overburden and the underlyingbedrock aquifers. A total of 22 monitoring wells were installed at the Dry Run Landfill to monitor the overburden and bedrock aquifers. Currently, five overburden wells and 10 bedrock wells still exist. The other seven wells were abandoned in 1999 by Potesta & Associates, toe. as required by the permit because these wells were not being utilized for quarterly monitoring (Potesta & Associates, 1999), Qroundwater Flow In the 4Q02 Surface Water and Groundwater report (DuPont, 2002k), revised groundwater elevation maps for 2Q02,3Q02 and 4Q02 were generated. These maps did not include data from the new wells because the site conceptualmodel had not yet been revised. Using the new geological interpretation of three distinct water-bearing zones and using groundwater elevation data from the new wells, new groundwater elevation contour maps were constructed for the A-Zone and the B-Zone using 4Q02 data. These maps are presented in Figures 6.8 and 6.9. The groundwater elevation map for the A-Zone (see Figure 6.8) shows that overall the direction of groundwater flow is toward (he west DRMW-14 was not used in the construction of this map because it is an open hole well and .water levels measured in this well may be influenced by shallow water bearing zones that are higher in elevation than the A-Zone. Figure 6.9 shows the direction of groundwater flow in the B-Zone. The groundwater contour lilies on this map are dashed because there are very limited data for we zone. However, groundwatCT flow direction in this zone also is generally toward the west. Groundwater flow directions in the underlying the C-Zone cannot be determined because there is only one well in the zone. However, a downward vertical gradient is indicated from the A-Zone to the B-Zone and to the C-Zone based on groundwater elevations observed in the three zones. WWK-C-8 Data Sunwiaty- text final Fab. 5,03 56 Wilmington, DE ASH021688 EID639920 c.8D3teSum.myHeport____________________DifyRunLandgl[ Water Quality Broundwater Quality Groundwater quality data for the Dry Run Landfill were presented in detail in Section 6.3.1. Fifteen wells monitor the overburden and the three underlyingwater-bearing zones (A-Zone, B-Zone, and C-Zone) at the Dry Run Landfill. The highestconcentrations of C-8 measured in the overburden and underlyingzones are found in the wells that are the closest to the toe of the landfill. The highestC-8 concentration measured in groundwater at (he Dry Run Landfill is 20.9 ng/1, significantlylower that the CATT-establiehed C-8 SL of 150 ug/L The highest concentration of C-8 in groundwaterused as drinking-water source by residences located within a one-mile radius of the landfill was 0.422 ug/L The highestconcentrations of C-8 in groundwater used as non-drinking-water and unused sources by residences located within a one-mile radius of the landfill was 0.54 and 0.974 ug/1,respectively. These values are also significantlylower that the C-8 SL of 150 ug/1. Surface-water and Leachate Quality Surface-water and leachate quality was discussed in detail in Section 6,3.1. Surfacewater and leachate sampling points have been monitored at the Dry Run Landfill. The leachate samples have shown the highest C-8 concentrations with a maximum concentration of 704 ug/L It is expected that leacbate from the landfill would have the highestconcentration of C-8 because the source for the C-8 is likely the landfilled materials. Leachate at the Dry Run Landfill does not dischargeto surface water. It is collected at the landfill and is treated at the facility. Six of the surface-water sampling points are located in the vicinity of the toe of the landfill, and four of these are associated with the landfill cap. The four sampling points associated with the landfill cap flow into the other two sampling points located on streams that discharge storrowater from the area, The maximum concentration measured for these six sampling points has been 87 ug/1. The other sampling point is located at the western property boundary. The highest concentration of C-8 observed at this location has been 39 ug/1, although, seven of the 11 samples collected from this point have had C-8 concentration less than 10 ug/1. With the exception of the leachate samples, the C-8 concentration of all surface-water samples have been less than the CATT-established C-8 SL of 150 ug/1. Further, these concentrations are significantly less than the Aquatic Life Advisory Concentration for C-8 (C-8 ALAC) of 1,360 ug/1. 6.5.2 Current Human Health and Ecological Exposure Pathways The main objective of the Consent Order was to determine whether there has been an impact on human health and the environment as a result of releases ofC.8 to the environment from DuPont operations at the Washington Works facility and the associated landfills (Local, Letart, and Dry Run). To meet this objective, human health and ecological exposure pathways both on-site (at the Dry Run Landfill) and off-site (adjacent to the Dry Run Landfill property) must be evaluated* The human health and ecological exposure pathway sections below describe the potential exposure routes for human and ecological receptors on- and off-site. Potential exposure routes were WWK.C-8 Date Summary - text final Feb. 5,03 57 Wilmtngton.DE ASH021689 EID63&921 \ .siS&s*, lIBIISl C.8PalaSummaiy Report ______________ Dry Run Landfill evaluated and classified as complete or incomplete. Table 6.5 summarizes the human health and ecological exposure pathway evaluation for the Dry Run Landfill, To be conservative, for each complete exposure pathway, the maximum C-8 concentration measured in the C-8 impacted media is compared to the C-8 SL. regardless of media type. On-Site Human Health and Ecological Exposure Pathways Current Environmental Setting The on-sile current human health and ecological exposure pathways section describes the potential exposure routes for human and ecological receptors that are found at the Dry Run Landfill. On-site human receptors include authorized facility workers and facility visitors. Ecological receptors include animals living within the landfill boundaries. Potential exposure routes were evaluated and classified as complete or incomplete. Access to the Dry Run Landfill by is controlled by electronic gates on the major roads and locked gates on smaller roads. In addition, because the landfill is active, there is a crew of workers nn the central portion of the landfill area during normal working hours. The institutional controls and the daily activity discouragestrespassers on the site. Direct contact with landfill materials or soils impacted by the materials in the inactive, lower half of the landfill is incomplete due to the leachate collection system's geotsxtile and geomembrane cover. However, direct contact with landfilled materials or soils impacted by the materials at the active, upper half of the landfill is a complete pathway and is limited to the workers in active portions of the landfill. Precipitation falling in the upper half of the landfill may infiltrate the soil and vegetative cover and contact the landfilled materials as it migrates downward. However, this impacted surface water flowing within the landfill will be collected by the leachate collection system. Contact with leachate captured at the landfill is an incomplete pathway. If this impacted surface water migrates downward throughthe landfilled materials, it may eventually contact the underlying shales and sandstone of the bedrock and migrate downward as groundwater into the bedrock aquifer. Contact with groundwater is considered to be an incomplete exposure route. The water-bearing zones that are monitored at the landfill are located at several hundreds offeetbgsat the upper end of the landfill. In the lower end of the landfill, the A-Zone is exposed at the surface. However, no seeps were observed in the areas where this zone is exposed, hi addition, in the lower end of the landfill, the depth to groundwater in the overburden is 5 to 8 feet bgs; therefore, contact with this gromidwater as an exposure pathway is also incomplete. Contact with C-8 impacted surface water near the toe of the landfill is considered a complete exposure pathway. However, this exposure pathway is limited because site workers follow health and safety procedures (i.e., personal protective equipment)when managing surface water at the site. The C-8 concentration measured in surface water in this area has ranged J&om 0.54 to 87 ug/1, less than the C-8 SL established by the CATT and significantly less mat the C-8 ALAC of 1,360 ug/1. Contact with C-8 impacted surface water at the property boundary is also a complete exposure-pathway for human and ecological receptors. C-8 concentrations at this location.have ranged from 0.88 to 39 ug/1, which are below the C-8 SL and are significantly lower than the C-8 ALAC. In WWK.O-8 Data Summaty- text final Fsb. 5,03 58 Wilmiratot>.06 .. ASH0216&0 EID639&22 c.spataSuft.marytopart____________Dry Run Landfill addition, C-8 concentrations measured in the seven of the 11 samples from this location were less than 10 ug/L Therefore, although this exposure pathway is complete, it is limited due to the low C-8 concentrations measured. Off-site Human Health and Ecological Exposure Pathways Off-site human receptors include residents usingthe water sources sampledduringthe groundwaterwell and water-use survey. Ecological receptors include livestock using the water sources sampledduring the groundwater well Mid water-use survey. West Virginia One-Mile Radius Groundwater and Surface Water Direct exposure to 0*8 impacted surface water and groundwater is considered to be an incomplete pathway in situations where the water source is not used. The pathway is considered-tcrbe-a complete-pathway when-the water-scmrceris-iisedtut not for drinking- water purposes althoughthe exposures is considered to he minimal because the water is :-i not ingested. The highestC-8 concentration in a non-drinking-water sample was ^ 0.54 ug/1,well below the C-8 SL of 150 ug/1(WVDBP, 2002). The pathway is considered to be complete if the well is used for drinking water. The highest C-8 concentration measured in drinking water was 0.422 ug/1, significantly lower than the CATT-established C-8 SL of 150 ug/1. Therefore, the pathway is complete, and exposure is considered to be limited due to the low C-8 concentrations measured. Outside of the one-mile radius, a surface-water sample was taken from the Lee Creek near a private residence. The C-8 concentration measured in the Lee Creek was 028 ug/1 (DuPont, 2002g). At this same residence, a drinking-water well and a spring used for non-drinking-water purposes also were sampled and analyzed for C-8. The C-8 concentrations measured in these water sources were MD and 0.331 ug/1,respectively. The exposure pathways for these water sources are complete. However, all three of these concentrations measured are significantly lower than the C-8 SL, 6.6 Dry Run Landfill Summary Many different activities have been conducted at and around (he Dry Run Landfill in order to determine whether there has been an impact on human health and the environment as a result of releases of C-8 to the environment from (he landfill. The C-8 concentration in groundwater and surface water from many sources (on-site, off-site, monitoring wells, production wells, private wells, springs,and cisterns) was measured. Based on all of the data evaluated for the Dry Run Landfill, the following observation . were made: Q The current exposure pathways are incomplete for human and ecological receptors contact with on-site leachate and groundwater. Q Human and ecological receptor contact with C-8 impacted landfill materials, soils, and surface water are currently complete exposure pathways. However, these pathways are considered to be minimal because of institutional controls on the property, personal protective equipment worn, and health and safety procedures that are in place and followed when working with or around the active landfill and when managing the leachate collected at the Dry Run Landfill and surface water. WWK-C-SDstS Summary -text final Feb. 5,03 59 Wilminatoti, DE ASH021691 EID639923 C-8 Data Summary Report Dry Run Landfill 08 0 Contact with surface water exiting the site that has been impacted by i$ also currently a complete exposure pathway for human and ecological receptors. The highest C-8 concentration measured in surface water exiting the site was 39 ug/1, which is lower than the CATT-established C-8 SL of 150 ug/1and lower than the C-8 ALAC of 1,360 ug/1(Menzie-Cura & Associates, 2002). C-8 concentrations measured in seven of the samples taken at the property boundary were less than 10 ug/1, indicating that while this exposure pathwayis complete, exposure is liinited because of the low concentrations of C-8 detected, 0 Current off-site exposure pathways for human and ecologicalreceptors that are complete but limited, due to the very low C-8 concentration measured, include residential drinkingand non-drinking-water sources. For the drinking and non" drinking-water sources, the highestC-8 concentration measured were 0.422 and 0.54 ug/1respectively, which are well below the C-8 SL of 150 ug/1and the C-8 ALAC of 1,360 ug/1(WV DBF, 2002; Menzie-Cura & Associates, 2002). 0 Evaluation of the C-8 results measured at the Dry Run Landfill, of the groundwater flow direction at the landfill, and of the one-mile radius C-8 results shows that C-8 impacted groundwater is not migrating off-site. 0 The on-site C-8 results for groundwater and surface-water support water transport as the migration pathway for C-8 from C-8 containing landfilled materials to surface water and groundwater. However, the Dry Run Landfill is located within eight miles southwest of the facility. Therefore, air transport of C-8 by air emissions from the facility cannot completely be ruled out, and maybe the source of C-8 for the very low concentrations measured within the Dry Run one-mile sampling area. WWK-O-B Data Summary- text final Feb. 5,03 Wilirengton, DE 60 ASH03;16&2 E1D639924 ; '^\ fill|| C-8 Data Summary Report References 7.0 REFERENCES DuPont 1990. Washington Works ] 990 Preliminary Hydrogeologic Assessment. Solid Waste & Geological EngineeringDepartment. ___ 1992. Verification Investigation E.L DuPont deNemours Co. Washington Works April 1992. (Vol. I). __ 1996. Report ofGeotechnical Investigation Dry Rm Landfill,Washington Works Main Plant, ParkersburgWV. Geotechnical Group, Civil Engineering Systems, DuPont Engineering. ___ 1999. RCRA Facility Investigation Report, DuPont Washington Works, June 30 1999, DuPont Corporate Remediation Group and URS Diamond, 2000. Letart Landfill Grwndwater Protection Plan SW/NPDES Permit No. __WV0076066, January 7,2000. DuPont Corporate Remediation Group and URS Diamond. 2001. Certification Report Letart Landfill Cap Construction, June 2001. , Corporate Remediation Group. 2002a. One-Mile Radius Survey and C-8 Sampling Report and Ohio River Public ______Water Supply Sampling, DuPont Washington Works (December 2001-February 2002) January 2002. DuPont Corporate Remedifttion Group and URS Diamond. 2002b, Compilation of Historical C-8 Data, DuPont Washington Works Main _____Plant and Landfills January 2002. DuPont Coiporate Remediatioo Group and URS Diamond. ^___ 2002c. Proposed Grwndwater Monitoring Plan for Washington Works Facility Plant and LandfillsJanuary 2002. DuPont Corporate Remediation Group and URS Diamond. 2002d. Email with attached map from Andrew Hartten of DuPont to the ,, Gioundwater Investigation Steering Team 2/25/02. 2002e. C-B Plume Identtfication/Groundwatef Assessment Work Plan. DuPont _ Washington Works Facility and Local, Letart and Dry Run Landfills May 2002. DuPont Corporate Remediation Group and URS Diamond. WWK-C-8 Data Summary- text tina) Feb. 5.03 WHmlngton, 06 61 ASH0216&3 BXD639925 C.8 Date Summary Report References ____ 2002f. January 2002 Groundwater Investigation Quality Assurance Project Plan for Washington Works Plant Washington, WV, January 2002. DuPont Corporate Remediation Group and URS Diamond. ___ 2002g. May 2002 Groundwater Investigation Quality Assurance Project Plan Addendum for Washington Works Plant Washington, WV, January 2002. DuPont Corporate Remediation Group and URS Diamond. 2002h- Two-Mile Radius Survey and C-8 Sampling, Mont Washington Works _,__ Facility/Local Landfill. West Virginia (March-May2002) August 2002. DuPont Corporate Remediation Group and URS Diamond. _ _ _ 2002L One-Mile Radius Survey and C-8 Sampling Report, WashingtonCounty, Ohio (March -June 2002) August 2002. DuPont Corporate Remediation Group and URS Diamond, _ _ _ 2002J.Two-Mile Radius Survey and C-8 SamplingReport, Washington County, Ohio (June - September 2002) December 2002. DuPont Corporate Remediation Group and URS Diamond. ___ 2002)c. Fourth Quarter 2002 C-8 Surface Water and Oroundwater Monitoring Report For Washington Works Facility and Local. Letwt and Dry Run Landfills Washington. WVDecembKt 2002. DuPont Corporate Remediation Group and URS Diamond. ___20021. Ohio River Water Sampling Results. Washington Works Facility and the Letart Landfill November 2002. DuPont Corporate Remediation Group and URS Diamond. ____ 2002m. 3Q02and 4Q02 Public Water Supply Results, West Virginia and Ohio. DuPont Washington Works, Washington WV November 2002, DuPont Corporate Remediation Group and URS Diamond. ,___ 2003a. Revised Groundwater Flow Model. DuPont Washington Works. Washington, WV January 2003. DuPont Corporate Remediation Group and URS Diamond. ___ 2003b. November 2002 Surface Water Monitoring Report For Washington Works Facility and Local, Letart and Dry Run Landfills Washington. WV January 2003. DuPont Corporate Remediation Group and URS Diamond. Bxygen. 2002. Personal Communication between"John Flaherty, OperationsManager, Bxygen Research, Inc. and Michael D. Aucoin, Project Chemist, URS Diamond. WWK-C-9 Data Summary -, text flnal Feb. 5,03 B2 Wilminalon, OE ASH021694 BID63&&26 c.6 P9teSur(OTitfy Report______^-__^_^_________________________^eferences Menzie-Cura &. Associates, he. 2002. Una/ Report, C8 Assessment ofToxicity team (CAT!) Report Addendum Aquatic LifeAdvisory Concentration for C8. Potesta & Associates, toe. 1999. Monitoring Veils MW-1, MW-1A, MW'4. MW-4A. MW-6. MW-10. MW-10 Abandonment Report, Dry Run Landfill, DuPont WashingtonWorks. March 1999. Simafd, C. ML 1989. Geological History of the Lower Terraces and Floodplains of the t}pper Ohio River Valley, Open File Report, West Virginia GeologicalSurvey, 160 p. Schultz, R.A. 1984. Groundwater Hydrology of the Minor Tributary Basins of the Ohio River, West Virginia. Tetra Tech "Richardson. 1990. Monitoring Well Installation Program at Lefart Landfill- Summary Report, August 1990. USBPA. 1994. Region HI Modificationsto National Functional Guidelines for Organic Data Review. WVDEP. 2002. Final Ammonium Perfluorooctanonate (C8) Assessment ofToxicity Team (CATT) Report. August 2002. West Virginia Department of Environmental Protection VMK-OB Data Summaly - text final Feb. 5,03 Wlhilngton, DE 63 ASH0216&5 EID63S&27 3 I ASH021696 EXD639928 Table 3.0 Summary of Off-site Sampling Program (C"8 Sampling) DuPont Washington Works Facility and Local Landfill Washington, WV RESIDENTIAL SAMPLING FOR 'I.MII.E RADIUS .:.'. 1 5 Number of homes contacted(1) 311 0 I Number of homes surveyed(1) 269 Number of wells identified(2) 51 1JS Number of wells sampled(2) 34 Number of wells sampled that are used for drinkingwater 6 V) Number of cisterns identified I2) 17 E s 1 Number of cisterns sampled!2) 6 Number of cisterns sampled that are used for drinkingwater 0 i. Number of springs identified <2) 8 > fi Number of springs sampled(2) 4 (0 Number of springs sampled that are used for drinking water 0 i(0 Total number of samples 44 8 Total number of collected samples used for drinking water 6 Note: Field duplicates not considered In sample count. (t) During this investigation, homeowners/residents identified within the sampling radius were contacted to determine residential water usage. Up to two contacts were attempted at each residence. After the second contact attempt, a voluntary survey was tell at the residence. Because not all homeowners/resldences responded to the survey, the number of residences surveyed is less than the number of homes contacted. 121Some water sources (e.g. welte, cisterns, springs) identified during the survey were not sampled. In many cases, sampling of these water sources was refused by the homeowners/restdents. In other cases, the water sources were either not accessible or damaged. As a consequence, the number of water sources sampled was less than the number of water sources identified. 2/4/2003 1of1 Tab 3.0 Consent Order T&F.xls ASH0216&7 EID639929 Table 3.1 Summary of C-8 Analytical Results In Groundwater and Surface Water (ug/l) Washington Works Facility and Local Landfill (Off-site Wells, Springs, and Cisterns - One Mile Radius) Washington, WV SairiDle ID SamoleDato C^ug/1 OS-ANfeARTR 12/ia@OOT 2.8 6S-BALSEYAR 12/21/2001 1.74 08.BALSEYAR 4/11/2002 2.48 OS<;HRI8TMANS 08-CHRJS'TOIANS r 6S-8MITHMT 08-VlNCENTS OS-VINC6NT8 WSf^\ W^fSSS. 0,328 0.526 ^"--n 2/S/2W2 1.33 12/17/2001 4/11^002 1.36 08-WILGOXA 1W2882 1,72 OS.WILCOXA , ........^.^^ 1,74 OS-AINSLEYB i/zefeooz 1.83 OS-BEElEED 'OS-BDWKfcNsHlPR 1/15/2002 2/21/2002 3.2 0.715 08-BURCHARDA ^ OS-BUHUbl IEP OS^CWM 1/9/2008 1/10^662 1/27/2002 0.418 1.7 2.93 OS-eAYTONW ?5/2002 3.63 08-COCHRANQ 1/2W2002 1.3 os.coRBirre 1/23/2002 0.945 OS<;OWANJW a%7/2002 14.3 OS-CREELKI ""^"""l^^BoS 2.7 ,,.,,,,,,,,.. OS-CREEfcKS Og^AVISJ -Qg^^j^ b.l^kER 0&-FURBE^ 1/27/2002 1/9ffi002 1/9/2002 1/23/2002 1^3^002 7.47 3.3B 0.569 0.32 5.07 OS.HENDRICKBB """1&6/2002 08-LAKEWASHC1 OS'LAKEWASHC2 mwz 1/18/2002 1.72 0.347 0.867 OS.IAWSONDHI 1/8/2002 9.56 OB-MmJER3 OS-WWUSS 'mm^ 1/- 4&002 ' OS-NEWHOUSES OS-^ARSONS D SSIsSsS ^ OS.RICHARDSV 12iWo01 08-RIDDLED1 WZ66W OS-WAYBRteHtt) 06-WHlTAKehK we/awe 'ij^^oog 8.94 0.932 0.304 3.44 2.37 8.24 0.252 2.3 Water Use* brinkinaWater "Blinking Water Drinking Water DrinklnpWater IprnMng Water DrnRHifl Water Drinking Water Drinking Water Drinking Water Drinking Wafer Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused UnusedT Unused Unused ''"''"ISiiise. Unused Wa6r Cattle Unused Uniiset Mtec. Unused Unused Misc. Unused Unused Misc. Unused Unused Unused OS-LAW80NDH2 OS-R1DDLED2 C^SHOCKEYG 08-TALLHAMbH 1/ioiecioE 2/T82002 i/27iaoo2 "V2teODg 10.9 2.8 1.33 1.63 Unused Unulea Unused Water Cattle" ' - ' SampleTvpe m Well Well Well Well Well Well Well '""""""--Well Well Well Well Well Well ' : Wen Well Well , ^ ^..,..,. -- --well Well Well Wel Wel Well Welt Wel Well Well Wel Well Wel Well Well Wel Well Well Wel Wel Sprinp Bpnhg Sprtiq Spring 1/29/2003 4:25 PM 1of2 Tab 3.1 Consent Order T&FJ<S ASH021698 EID639$30 Table 3,1 Summary of C-8 Analytical Results In Groundwater and Surface Water (ug/1) Washington WorHs Facility and Local Landfill (Off-site Wells, Springs, and Cisterns - One Mile Radius) Washington, WV Sample ID Sample Date C-81K1/1 osm ww OS*AI UNSU OS-PORl EREL OS^MITHMM OS-THOMPSONB oswrKiRSci. 1/2W2002 3.15 12/18/2001 ij56 12/19^001 O.S61 T2?l7^oSl 8.48 12/17/2001 """"ll"""""":^ 12/17/2001 """" -(.32 Water Use* Unused Misc. Misc. Misc. Water Cattle Mtec. Sample Type Cistern Cistern Cistern Cistern Cistern CtetBm ' Drinking Water (WghllghtedIn bold blue) indicates human consumption, (ton-drinking Water uses include livestock walering.gartlering and any olher non-human consumptiDn water uses. Miac." Miscellaneous water use b not used (or drinking. Data highlighteidn yellow are resute for water sources located within the Ons-mile radius that were lesampled duringW two-mlla radius eamplingevent 1/29/2003 4:2S PM 20(2 Tab3.< Consem Order T8iF.x)s ASH021699 EXt)63$&31 Table 3.2 Summary of Off-site Sampling Program (C-8 Sampling) Washington Works Facility and Local Landfill Two-mile Radius DuPont Washington Works '... RESIDENTIAL SAMPLING FOR THE 2-MILE RADIUS m <D Number of homes contacted(1) 667 Z Number of homes surveyed m 109 Number of wells identified<2) 98 jtO "55 Number of wells in sampledt2) 52 S Number of wells sampled that are used for drinking water 17 . Number of cisterns identified<2) 17 | Number of-cisterns sampled(2) 8 0 Number of cisterns sampled that are used for drinking water 0 (0 Number of springs Identified(2) 7 0) E. Number of springs sampled(2) 5 & OT Number of springs sampled that are used for drinking water 1 '3. Total number of samples 65 E a V) Total number of collected samples used for drinking water 18 Note: Held duplicates not considered In sample count. m During ttlia investigation, homeowners/residents Identified within the sampling radius were contacted to determine residential water usage. Up to two contacts were attempted at each residence. After (he second contact attempt, a voluntary sun/ey was left at the residence. Because not all homeowners/resldences to the survey, the number of residences surveyed is less than the number of homes contacted. "'Some water sources (e.g. wells, cisterns, springs) Identified during the survey were not sampled. In many cases, sampling of these water sources was refused by the homeowners/residents. In other cases, the water sources were either not accessible or damaged. As a consequence, the number of water sources sampled was lass than the number of water sources identified. 2/4/2003 lof-l Tab 3.2 Consent Order T&F-Xls ASH021700 EI0639&32 Table 3.3 Summary of 08 Analytical Results In Groundwater and Surface Water (Off-site Weils, Springs, and Cisterns) Washington Works Facility and Local Landfill Two-mile Radius Washington, WV 2-Mile Sample ID OS*HAMILTONF OS-UNQERAC1 bS-STEPHEN$OS 08-STEPH6NS6E 08-MCMAHANGE OS-BAKERER 08-JAMESONRD OS-COLVINRL OS-FOUTTBl. OS-NAYJL 08-BOSOEC OS-HESSOK OS-NEWBERFIVPC OS-MIILLSLS 08-SMTMPL OS-PHIL PSAE OS-C01.EMANC1 OS^OHNSONLI OS-W6ATHERHOLTU 08-QARNE8AL OS-RHOADESRW OS-WIGAU OS.YOSTJ OS-GOLDSMrrHML OS-SAMSCW OS-SACCHID 0&-JOHNSON1.2 OS.LlN<3eRA<% OS-ARNOLDWC OS-RWKERC OS.WOLFEDJ OS-WYATTV6 OS-DOTSONM 08-EATONJD 0&-HAMMONDE OS-CAMPBELLQ OS-SARTORL 0&01A8SC 08-MATHEWSJR 0&-REEDERHJ OS-M1LLSS OS-TUCKERCM OQ-TALLMANE 08-UFEM 08-MOREHEADV OS-NORMANE Date 3/14/2002 3/1-^002 3/14/2002 3/14/2002 3/15/2002 3/18/2002 3/18^602 3/19^002 3/19/2002 3/19/2002 3/2B/2002 3/28/2002 4/3/2002 4/18/2002 4/24/2602 4/25/2002 8/4/2002 3/14(6002 3^0/2002 4/3/2002 4^9/2002 sia/aooz sn4fssm 5/20/2002 e/swaoaz BQ1/2002 a/14^602 3/14&002 4W2002 4^(2002 4/a'aoog 4/12/2002 B/Q/26QZ 6/8/2002 5/10/2ffl02 5/13/2002 5/iai2002 5/i4002 S/14/S002 5/14^002 8/21/2002 5/21/2002 S122/2QQ2 5/23/2002 S%9/2002 5/29/2002 C-8ugrt0.737 ND (<0.010) 0.62S 0.229 ND(<0.010] NQ(<0.050) NO (<0.010) 0^42 0.899 0.465 Ndi<0.050) hl0r<6.050) 0.386 ND(<0,016) ND(<:0.010] 0.73 NDi<0.010) ND <0,010J 0,078 1.3 1.66 0.625 6.081 0.874 IS ND(<;0.010) 1.08 1.88 2 0.70B 0.17 1.19 0.164 ND(<0.010) 0.074 0.091 0.927 0.425 0.781 1.17 157 0.095 0.325 0.257 1.19 0.692 Water Use* Drinking Water Drinking Water DrinkingWater Drinking Water Drinking Water Drinking Water Drinking Water Drinking Water DrinkingWater Drinking Water Drinking Water Drinking Water Drinking Water Drinking Water DrinkinaWater Drinking Water Drinking Water Non-drlnklna Water Non-drinking Water NorKirinklnpWater Non-drinkingWater Non-drlnMng Water Non-drinking Water Non-drinking Water Non-drinkinfl Water Non-drinking Water Unusoc Unused Unused Unused Unusec Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Sample Type Well Well Well Wetl Well Well Well Well Wel Well Well Well Well Well Well Well Well Well Well Well Wel Wel Wel Weil We) Well Wel Wel Wel Wel Wel Well Weft Wetl Well Well Wel Wel Wel Wel We) Well Well Well Well Well 1/30/2003 1of2 Tab 3.3 Consent Order T&F.XIS ASH021701 B1D639933 Table 3.3 Summary of C-8 Analytical Results In (aroundwater and Surface Water (Off-site Wella, Springs, and Cisterns) Washington Works Facility and Local Landfill Two-mite Radius Washington, WV 2"Mile Sample ID OS-BIRAMB 08-VAUGHNDE 0&-MITCHEH.L OS-SM1THLK OS-WRIOHTW 08-R1CHARD8C OS-STUTTLERLR 08-BLOOMKRCe OS.BURTOND6 OS-IWTENHOU8E OS-ARTHURR8 OS-WALTERSMM ^ 08-WILUS). OS-HERTZr. OS-BLUBRE OS-EDDYMM1 OS.EDDYMM2 08-PUGHJA OS-NUTT6RK Oate S/29/2002 5/30/2002 5/30/2002 51ffi002 e/a^oos 6/3/2002 3/27/2002 3l^002 4/18/8002 4/16/2002 3/20/2002 3/22/2002 4/24/2002 4/25/2002 4/18/2002 4/24/2002 4/24/2002 5/14/2002 5/22/2602 C-8U9/1, 0268 ND (<0.010) 1.26 0,092 1.07 1,62 1.8 0.857 0.823 0.898 2.32 1.39 0.772 1.67 0.447 2.27 1.84 NQ (<0.050) 0.174 Water Use* Unused Sample Type Well Unused . Well Unused Unused Well Well Unused Well Unused DrinkingWater Non-dririking Water h on-drinking Water Well Sprint W Sprinc ^ , hton-drinking Water , Unused NwMinnking Water ^"S SprinE Cistern ston-drinking Water Cistern on-drinktna Water Cistern Unused Cislerr Unused CIsterr Unused CIsteir Unused Unused Cistern Cistern * Drinking Water (highlightedtn bold blue) indicates human consumption. Non-drinking Water uses include livestock watering, gardening and any other non-human consumption water uses. ND " Not Detected at or above tha limit of detection (IOD). The listed LOD is approximate and varies by instrument and over time. NQ = Not Quantifiable. Detected at a concentration abwe the IOD and below the limit of quantification (LOQ). 1/30/2003 2of2 Tab 3.3 Consent Order T&F.xls ASH021702 EID63&934 Table 3.4 Summary of Off-site Sampling Program (C.-8 Sampling) Ohio One-mile Radius Residential Sampling DuPont Washington Worte RESIDENTIAL SAMPLING FOR OHIO 1-MILE RADIUS u 1 Number of home? contacted (1) 361 Number of homes surveyed(1) 150 Number of wells identified(2) 78 Iw> Number of wells sampled(2) 47 Number of wells sampled that are used for drinking water 17 . I/I Number of cisterns identifiedt2) 16 E 1 Number of cisterns sampled that are used for drinkingwater(2> 5 O Number of cisterns sampled that are used for drinking water 0 1u> Number of springs identifiedt2) 15 E? Number of sprinas sampled(2> 15 Number of springs sampled that are used for drinking water 1 01 Pool 1 1 V. Total number of samples 68 Total number of collected samples used for drinking water 18 Note: Field duplicates not considered in sample count. w During this investigation, homeowners/residents identified within the sampling radius were contacted to determine residential water usage. Up to two contacts were attempted at each residence. After the second contact attempt, a voluntary survey was left at the residence. Because not all homeowners/resldences to the survey. the number of residences surveyed is tess than the number of homes contacted. ^Sorne water sources (e.g. wells, cisterns. $prings)Identified during (he survey were not sampled. In many cases, sampling of these water sources was refused by the homeowners/resldente. In other cases, the water sources were either not accessible or damaged. As a consequence, the number of water sources samples was less than the number of water sources identified, 2/4/2003. .1of1 Tab.3,4 Consent Order T&P.xls ASB021703 EID639&35 Table 3.5 Summary of C-8 Analytical Results in roundwater aiiid Surface Water Ohio One-mile Radius Residential Sampling 1-MHe Sample !0 OS.MAROUMLL 08*KANITZKP OS-KANITZKP (dup] OS-RUMERJh 08-RYANSP OS-8WAINPM OS-WILCOXENWT 08.COU-INSRSOa-PARLEYFL OS-PRICEPL OS-HORNBECKLK OS-LEGLEffNERJK 08-MATHENYBL OS-MATHeNYTL OS-EDDYEE OS-PAR80NSCF OS-eERBERDA OS-6IVEN8DL 08-SMITHPW1 68.WICKHAMYD 08-RYANSP1A OS-ARMOR!^ 08-BAIUE8MD OS-PIERCBJ OS^HEPPARDRO OS^UCHSBL OS^ICKLESTS OS.LEFEBVR6SA os-RipperoK 08-WATSON MP1 OS-PARSONSDOH OI..COLLINSRL2 OS.DAU<3HERTYD OS*MCQEET OS-MAYLEVJ OS-WINDLANDB 08-HUMEJD OS^HETLERF 08-CURREYIA OS^FPANSlCOl O&WILLIAMSG OS-STAHLPR^ 08.8TAHLPR4.2 OS-OTAHLPR3 ^&NATH6NYB Sample Date 3/20/8002 3/21/2002 3/21/2002 9/21/2002 3/81/2602 3/21/2002 3/21/2002 3/22/2002 3/22/2002 3/22/2002 4/1/2002 4/1/2002 4/1/2002 4/1/2002 4/3/2002 4/8/2002 4/17/2002 5/22/2002 3/20/2002 3/20/2002 3/21/2002 aS002 4/18/2002 4/15/2002 4/17/2002 S/22/200B 4/8/2002 4/11/2002 4/16/2002 4/18/2002 4/83/2002 5/1/2002 5/1/S002 5/1/2002 8/SE/2002 66/2002 5/3/2002 5/3/200S SW2002 S/8/2002 MKWO& 5/15/2002 5/15/2002 6/156002 5/15/2002 C-augrt, ND(<0,010) 0.303 0.286 3.91 0.09B2 0.203 NQ (<0.050) 0.2?4 0.239 O.W2 0.237 ND (<0.010li 0.0805 0.185 6.4 8,59 0.102 0.416 135. 0.0842 0.278 0.675 1.24 3.B ND(<0.010) 0.955 12.1 12.9 4.49 17.2 2.09 0.104 18.9 0.0701 1.11 11.5 2.35 0.161 NDj(<0.010^ 16.7 1.35 6.35 6.36 11.1 O.S82 WaiwUse* DrinHinBWater DrinWnqWater DrinMnqWater DrInWngWater DrinWftaWi ater DrinMnq Water Drirtang Water Drirt<ing Water DrinhingWater DrinkinWgater DrinHlngWaler DrinkinqWater DrinkingWater DrinkingWater DrinkingWater DrinkingWater DrinkingWater DrinkingWater Non-drinkiWngater Non-drinking Water Non-tlrtnkina Water Non-drin singWater Non-drindng Water Non-drinking Water Non-dnnking Water tton.dnnkina Water Unused ^Qnused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Unused Sample Type Well Weil Wed Well Well Well Well Well Well Well Well Well Well Welt Well %ii Weil Well Well Well Well Well Well Well Well Well Well Weil VNI Welt Well Well Well Well Well Well Weil 'Welt Well Well Well Well Well Well Well 1/30/2003 1of2 Tab 3.5 Consent Order T&F.xls ASH021704 EID63&936 Table 3.5 Summary of C-8 Analytical Results in Qreundwater and Surface Water Ohio One-mile Radius Residential Sampling 1-MHo Sample ID Sampte Date OS-THOMPSONAM 5/16/2002 08-ARBAU6HJ 5/23/2002 08-YATE8L 5/24^002 08.SPICERRF " ^ "OiS-STAHt.PRZ 4/15Q002 4/8/2002 OS-STEPHANM12 4/9/2002 08-RAUCM 8PG1 4/11/2002 RAUCH8P62 4/116602 OS-RAUCH8PQ3 4/11^002 OS-RAUCH8P64 4/11/2002 08-RAUCH SP66 OS-WATSON MP2 4/11/2002 4/18/2002 OS-WATSON MP3 4/18/2002 OS-SWEARINQENW 4^2/2002 OS-8TAHLPR1 4/6/2002 08-CA8TOB1 6/7/2002 OS-CASTOB1-2 6/7/2002 0$-CASTOB2(dup) OS.CA8TOB3 6/7/2002 6/7/2002 0&.ST6PHANML OS.FAHLEY6D 4/9/2002 4/15/2002 OS-WATSON MP4 4/1B/2002 OS-B6EGHJB a'29/2002 OS-BARICKMANCH 6/4/2002 OS-STEPHANML8 4/9/2002 0-8uaffl. 4.22 1.02 3.2$ 1.29 5.72 8.88 3.58 4,67 4.4 4.97 5.76 18.1 23,8 8.55 4.97 3.81 4.3 2.96 6S35.41 1,26 7.33 2.85 0.748 2.52 Water Us* Unused Unused Unused OrinMnWg ater ^ Non-thinking W a t e r Non-drinking Water Non-drinkingWater Non-drfnMng Water Non-drinking Water -, Non-drinking Water Non-drinking Water ., Non-drinking Water r'on-(lrin(ng Water 'i on-drtnkfriWqater ^on'drlnlciWngater NorHitinkinWgater Non-tlrinkina Water Non-drinking Water NotMirinMna Water Non-drinking Water Non-drinking Water Non'drinldng Water Unused Non-drinkinnWater Non-drinking Water Sample Type Well Well Well - ^SprN Spring Spring Spring , . ,-My Spriiifl JfiriM ..... Spring Spring Spring Spring Spring Spring Sprtna JisM Spring Cistern Cistern Cistern Cistern Cistern "FooE * DrinkingWater (hahtighted in bold blue) indicates human consumption. Non-drinking Water uses include livestock watering, gardening and any other non-human consumption water uses, NO = Not Detected at or above the limit of detection (LOD). The listed LOD is approximate and varies by instrument and over time. NQ = Not Quantifiable. Detected at a concentration above the LOD and below the limit of quantification (LOQ), 1/30/2003 2of2 Tab 3.5 Consent Order T&P.xls AgH02l705 EID639937 Table 3.6 Summary of Off-site Sampling Program (C-8 Sampling) Ohio Two-mile Radius Residential Sampling DuPont Washington Works ": RESt@ENTW- SAMPLING FOR OHIO 2-iyilt.E RADIUS t Number of homes contacted(1) 1131 3: Number of homes surveyedl1) 733 Number of wells identified(2) 123 1. Number of wells in survey sampled(2) 58 Number of wells sampled that are used for drinkingwater 49 w Number of cisterns identified(2) 7 Number of cisterns sampled<s) 3 0 Number of cisterns sampled that are used for drinking water 0 ! Number of springs identified a) 3 Number of springs sampled(2) 1 ^ Number of springs sampled that are used for drinking water 0 i i Total number of samples 62 s Total number of collected samples used for drinking water 49 Note: Field duplicates not considered In sample count 0> During this investigation, homeowners/residents Identified within the sampling radius were contacted to determine residential water usage. Up to two contacts were attempted at each residence. After the second contact attempt, a voluntary survey was left at the residence. Because not all homeowners/residwces to the survey, the number of residences surveyed Is less than the number of homes contacted. w Some water sources (e.g. wells, cisterns, springs) Identified during the survey were not sampled. In many cases, sampling of these water sources was refused by the homeowners/residents. In other cases, the water sources were either not accessible or damaged. As a consequence, the number of water sources sampled was less than the number of water sources identified. 2/4/2003 1of1 Tab 3.6 Consent Order T&F.xls ASH021706 EH3639&38 tans A 3 C 1/30/2003 Table3.T Summary of C-8 Analytical Results Zones A, B and C Ohio Two-Mile Radius C-8 Residential Sampling Sample ID Sample Dal(i OS-AnkromCA OS-BedllionWW 7/9^18 7/1^002 OS-BoringAE 6/28/2002 OS-Cahtle^WA 7/19^002 08-CollinsNJ 7/9/2002 08-HairohC 6/26%002 OS-HoleombB 7/25/2002 OS-KnottsC 9/10/2062 OS-UKI&IM 7/9/2008 OS-McLauflNlnJL 712412002 OS-PhiBlpsPJ 7/2/2002 (JS-WaltonDI^ ' OS.WhiteAl- 6/26/2002 7/6/2002 OS-BoarcU 08-BosoFE OS'&ichananAP OS.pTeffiingWV 8/6/2002 7/28/2002 7/2S/2002 8^2/2062 OS'QrimRF 08-KldderEW 08-MeKowFl OS-Mereer^E 7/30/2002 9/17/2002 7/24/2002 7/24/2002 OS-MerinarJL Oe-SmtthDC OS-^mlttiWW OS^SonlenC OS-SSarkeyRF fiS-ThonfiasJB 08-WelclihJD OS-WelteB OS-WilltamsH 08-WiteonRMI 6&WilsonRM2 OS-FrameRD OS-SEtfn&R 9/23/2002 7/31/2002 9/12/2002 9/10/2002 7725/2002 9/19/2002 8/16/2602 8/17/2002 S/30/2002 7/31/2002 7/31/2002 7/24/2002 6/8/2002 OS-SplresRA OS-TuHezeliJM OS-AdamsQL OS-BowersockVK 08-CastoHg 08-CooltJM 08.Pavte)H OS-FoSlerTV OS-RrgginsJL C^-JacobsDK OS-KautzCR OS-KempN OS-KeNsonD 8/8/2002 9/5/2002 8/22/200S 8/14/2002 8/16/2002 8/14/2002 9/11/2002 8/14/2002 8/15/2002 8/16^002 8/22/2002 . 9/11/2002 9/11/2002 C-Sugfl, 0.059 1,710 1.150 Water Use* Drinktr^Water brinHinaWaler DrtnHiraWater 1.490 0.881 Drinking Water Drinhina W a t e r 0.844 NQ(<6.05] Drinkiita Water DrinMngWater 2.590 2,130 0.064 2.240 0.413 3.960 Drinkina Water Drinking Water DrtnktaflWater OrinkinflWater Drii'>Mr>gWaler OrinWnoWater 6.500 0.290 0.785 NO (:e0.05; OriinlungWater DrinMnftWater DrinkingWater OrlnkingWater O.S01 DrinMnaWater 4.150 Non-drinMna Water 0.973 Nan-diinWng Waier 0,784 DrinkinfWl ater 0.848 DrinMn^Weter 1:8110 DrinMno Water a.oS6 0.269 0.164 6.380 6.860 Unused DrinkinpWater Nort-drfnktnB Water Non'drlnking Water Nton-drinkinW^ ater 7.290 Ur>used 8.680 2.040 Unused DrinSdnWgater 4.7SO NorMlrinklnBWater 3,020 Non-drinkinq Water 0,592 Nwi-drlnklna Water 0.217 NorMlrtnMnn Water 0.374 Non-drtnMngWater 0.206 0.083 0.092 ND <0.01) ND <6.01) DrinMna Water Drinking Water DrinMng Water Drinking Water Drinking Water 0.812 ND (<0.01) DrinMng Water Drinking Water NDK0.01) NDr<a.6l) 0.091 0.092 OrinkOTgWater Drinking Water Drinking Water Drinking Water Sample Type Welt Well Well Well Well Well Well Weil Welt Well Well WeH Well Well Well Well Welt Weii Well Well Well ~^" Well "Well ireii Well Well Well Well Well Well Well Welt Spring Cistern Ctetem Cistern Wei Well Well Well Well Well Welt - "well WeJl Well Well 1o(2 Tab 3.7 Consent Order T&P.xls ASH021707 EID639939 Table 3.7 Summary of C-8 Analytical Results Zones A, B and C Ohio Two-Mile Radius C'8 Residential Sampling Zone C (cont.) eampreiD 08-KlnpCD OS-KlnaCD-2(DUP| OS-KtrkWE OS-KnoxGT OS-MitlironMP OS-MoodyDA OS-ShivelyJM OB-SouthallS? OS-SpaderJD 08-Sl.Cteir OS*8timpertPe OC-TatttWJ OS-Transport OS-WebbD 08-WheatonCA " OS*Wheat6nDl, Sample Date a/16/2002 we/wos 8/14/2002 8/16/2002 8/21/2002 8/20/2002 8/22/2002 a/as/abos fl/16/2002 9/S5/2002 8/21/2002 9/Sffi002 a/16ffi002 9l2S&0(& SlSAfSS02 wmm C-Bug/L ND(<0.01) ND(<0.01) ND(<0.01) ND(<0.01) ND (<0.01) ND (<0,01) NQ(<O.OS) 0.085 ND (<0.01) NQ <0.0i ND <b.01' 5.610 ND(<;0.01) 0.128 NQ(<0.05] 0.087 WatesrUaa* DrinkingWater Drinking Water Drinklnfl Water DfinkinqWater Drinking Water DrinklnqWater Diinktnfl Water DrinkinflWater Drinking Water Drinking Water DrinkingWater Drinking Water DrinkinoWeier DrinkingWater Drinking Water Dunking Water Sample Type Well Well Weil Well Well Well Well Well Well Well Well Well Well Well Well Well " Drinking Water (highlightedin bold blue) indicates human consumption. Non-drinking Water uses include livestock watering, gardening and any other non-human consumption water uses. ND = Not Detected at or above the limit of detection (LOD). The listed LOD is approximato and varies by instrument and over time. NQ K Not Quantifiable. Detected fit a concentration above the LOD and below the limit Of quantification (LOO). 1/30/2003 20(2 Tab 3,7 Consent Order T&F.xls ASH021709 BID639940 Tabled Monitoring Well Construction and Groundwater Elevation Data BuPonf Washington Works Faclitty Washington. WV NawWelltD Old Well ID Measuring Point Elevation (ft) rotal Deoth (ft) WallDlaniater (Inchest Sfot Size (Inches) AEtt-UWOI AJaa-tawo2 AM07.PW01 Aooa-pwo-f AX13^'W01 oovwm E13-MW01 , TW-74 338 331 338 TW-M5 7W-76 828.94 69.29 2 0.010 635.55 128 2 8.010 834.26 96 ' 63251 96 18 18 630.69 80 1& 600.87 4 625.47 76.8 2 0.010 Screen Length (ft} BavaHono? Screwl Interval (} 10 15 20 20 13 S89.6B 559.6S 522.55. 507.55 . .,^.;-.^, 558.26838^6 557.91 5S7.81 553.69540.69 ^g^iHidli!lte^g((BBfl^r(:^ January-02 567.02 -- * * -- February-02 SB6.02 -- * * 4r MarcMa SS4.20 ~ * * w April'02 58553 -- 4 * * May-02 S86.54 -- * * * August-02 567.61 -- * * October-02 568.52 ' 569.5S t * fr *Groun<lwater elevations not measured in production wetts, "Well was dry t0 568,87- . 548.67 ^ "T"^::? 582.73 '.^ " 561.29 562.69 561.12 sezoa 562.04 562.S1 560.5Q 582.71 560.76 564.55 562^3 584.J24 561.91 1/30/2003 1of2 Table 3.8 Monitoring Well Construction and Groundwater Elevation Data OuPont Washington Works Facltty Washington, WV ;;: New Well ID Old Well ID Measuring Point Elevation (.ft) rotai Depth (ft) We!! Diameter [Inches) Slot Siza (Inches) N04.MWC3 N113-HW01 P04-MtW02 P08-MW01 Q04-MW02 R04-MW02 V05.PWB1 RorrsMW-5 W-83 ROB'SMW^ RwrsMW-1 TW85 RANNEY 585.44 88.5 2 10 825.B7 58.95 2 0.010 892.38 27.81 2 0.010 S29.29 68^3. 2 598.76 39.64 2 594^2 27.64 2 0.010 632.00 82 NA Screen Length (ft) Bavstion of Screen Interval (tt) January-02 15 5 10 5 10 10 1 521.94. 508.94 570.92 585J&2 '. . -;'. ' i ,, -- -- 574.58564.S8 S66.99. 56059 569.1255&42 577.28S67.28 542.00 541 .TO ..^ ^^ft:"^- ': .. S7&35 ^"' :.i:-s?<5lriota,uwals-fcipaa -- 560^8 576,61 ft'.'-. "; .' ' " * ^abruary-02 -- 559.82 571.91 560.10 560.05 578.39 * flarcli-02 -- * 873.35 *. 559.45 577.36 * AprU-02 -- .* 573.13 ** 560.40 576.87 * May-02 -- *4- 574,32 ft* 559.77 577.10 August-02 -- * 572.6& ** 563.77 578.26 * OetobBr-OZ 567.82 *' 572.11 562.0& 583.06 574.98 Gfoitndwatereievations not measured In production wells. "Well was diry 1/30^003. 2of2 1/29/2003 Table 3.9 Summary of Analytical Results: C-8 in Groundwater DuPont Washington Works Facility Washington, WV Samplft AK11-MW01 AJ08.MW02 AM07.PW01 A008.PW01 AX13-PW01 Date 10/16/2002 8/4/2002 5/23/2002 4/29/2002 3/26/2002 2/22/2002 1/28/2002 2/2/1899 11/16/19&9 10/16/ai^ 10/226002 8/26/2002 5/17/2002 4/16/2002 3/21/2002 2/14/2002 1/22/2002 11/20/2000 8/16/2000 6/12/1999 2/3/1999 11/1S/1998 8/19/1898 6/2/1997 4ffi/1996 10/22/2002 B/26/2002 5/17/2002 4/16/2002 3/21/2002 2/14/2002 1/220002 11/20/2000 11/20/00 (Alp) 8/1S/2000 5/12/1899 IS/19W&8 6/2/1997 4/2/1886 10/22/2002 8/26/2002 5/17/2002 4/16te002 3/21/2002 2/14/2002 C^tHfl/O 1.74 1.92 1.25 1.22 2.82 1.45 1.20 . 0.69 L 0.41 0.133 0.2% 0.335 0.247 0.1S8 0.171 0.129 0.131 0.24 0.071 J O.S78 0.0826 1.9 L 0.4 0.79 0.48 0.415 0.42 0.499 0.497 O.S68 0.439 0,388 0.4 056 0.167 0,307 1 0.55 0.52 6.721 0.834 0.911 1.42 1.22 1.03 1of4 Tab 3.9 Consent Order T&P.xls ASH021711 EID639943 1/29/2003 Table 3.9 Summary of Analytical Results: C.B In Qroundwater DuPont Washington Works Facility Washington, WV Smpte D08-MW01 B13-MW01 KWW01 L04.PW01 N04-MW01 N04-MW03 Date 10/16/2002 9/4/2002 5/23/2002 4/29G002 3/202002 2/22/2002 1/28/2002 10/16/2002 9W2002 8/23/2002 4/29/2002 3/28/2002 222/2002 1/28/2002 6/12/1999 2/2/1999 11/11/189B 10/22^002 8/26/2002 5/1'W2062 4/16/2002 3^1^002 2/1-y2M2 1/22/2002 11/20/2000 2/9/1899 11/18/1998 10/2S/2002 8/13/2002 ^ 6/21/2002 4/18/2002 3/21/2002 2/7/2002 1/15/2002 7/11/2001 4/11/2001 mo^ooo 2/7/1999 11/18/1996 11/18/98 (Alp) 1/28/2002 10/16/2002 C.BtugW) 0,126 0.117 0.551 0.424 0.262 1.27 0.882 3.43 2.39 2.47 2.44 1.62 2.32 2.11 0.882 0.691 2 16.2 9.71 12.4 13.2 17.2 12 10.9 7.5 16.2 0.48 L 14.3 3-OS 16.1 16.1 40.9 23.5 30.9 0.202 3.89 13.8 8.89 7.9 J 3,9J 689 21.2 2 of 4 Tab 3.9 Consent Order T&F.x)s ASH021712 EID639944 1/29/2003 Table 3,8 Summary of Analytical Results: C-8 in Oroundwater DuPont Washington Works Facility Washington, WV sawipte N13-MW01 P04-MW02 PO&-MW6T Q04.MW02 R04-MW02 Data 10/16/2002 9/4/2002 912312002 4/29/2002 3/28/2002 2/26/2002 2/2/1999 11/11/1998 10/16/2002 10/16/02 (duo) S/4/2002 S/23/2002 4/29/2002 3/26/2002 2/28^002 1/28^002 1/25/2001 2/6/1889 11/12/1898 10/16/2002 9/4/2002 5/23/2002 4/29/2002 3/28/2002 2/25/2002 2/4/1999 11/13/1988 10/16/2002 9/4/2002 5/23/2002 4/29/2002 3/26/2002 2/25/2002 1/28/2002 2/4/1999 11/13/1998 10/18/2002 9/4/2002 S/23/2002 4/29/2002 3/26/2002 2/2S/2002 - 1/28/2002 1/25/2001 2/6/1999 11/12/1898 M M ) Dry-no sample Dry-no sample Dry-no sam^e Dry-no sample Dry-no sample 57.8 29.6L <0,1 46600 48300 34400 42400 36500 32300 26800 23600 12600 13600 8300 120 Dry-no s a m p l e Dty-no sample Dryno sample Pump problems-no sample 20.7 43.4 30 7720 32.2 1480 1210 2070 1590 1480 994 660 84100. 66500 68100 56300 54400 43600 47600 13800 3420 1300 3 of 4 Tab 3.9 Consent Order T&F.xls ASB021713 BID639&45 Table 3.9 Summary of Analytical Results; C-8 in Oroundwater DuPont Washington Works Facility Washington, WV Sample V05-PW01 Y14-MW01 Y14-MW02 West Well Pteld(l) Date 10/25/2002 8/13/2002 8/21/2002 4/18/2002 3/21/2002 2/7/2002 1/15/2002 7/11/2001 4/11/2001 11/20/2000 2/7/1999 2/7/99 (dup) 11/18/1998 10/16/2002 9/4/2002 5/23/2002 4/28/2002 3/280002 2/22/2002 1/28/2002 2/2/1999 11/10/1998 10/166002 10/26/2002 8/13/2002 5/216002 4/16/2002 3&1/2002 2/7/2002 1/16/2002 7/11/2001 4/11/2001 C-adiaTO 51.2 34.8 35.8 37.8 40.9 28,1 29 11.4 5.48 13.7 12.4 3,95 0,68 L 18.2 18.4 16.3 13.9 1S.5 10.9 12.7 4.9SL 12 N0^0.06) 10.3 6.41 7.09 8.69 7.72 8.77 6.52 2.31 1.58 J = estimated value (below laboratory quanlllfcatiorlimit) L a possible tow Mas result (relative to QA/QC) B= compound detected In QC blank Note: Analytical method changed as of November 2001 (sec Section 2.0 otDuPont (Z003b) for details). 1/29/2003 4 of 4 Tab 3.9 Consent Order T&F.xls ASH021714 EID639946 Table 3.10 Summary of Analytical Results: C-8 In Surface Water DuPont Washington Works Facility Washington, WV ".s^te OUTLBT001 OUTFALL 002 OUTLET 003 Data 11/13/2002 10/18/2002 9/24/2002 8/27/2002 7/23/2002 6/26/2002 5/20/2002 4/166002 3/1S/2002 2/S/2002 1/17/2002 12/20/2001 11/13/2002 11/13/02 (dlip) 10/18/2002 9/24/2002 8/27/2002 8/27/02 (dup) 7/23/2002 6/2S/2002 6/25/02 (dupL 5/20/2002 4/16Q002 3/19/2002 2/6/2002 1/17/2002 12/20/2001 11/26/01* 10/25/2001 9/19/2001 7/11/2001 6/14/2001 5/31^001 4/11/2001 3/21/2001 2/14/2001 11/13/2002 10/18/2002 6/24/2002 8/27/2002 7/23/2002 6/2S/2002 800/2002 4/16/2002 3/19/2002 .3/18/02 jdup) 2/6/2002 Miug/l) . 17.0 10.5 2.18 2.94 8.63 17.9 22.4 19.7 21,4 9.43 10,9 3.72 4.76 S.28 3.49 2.14 2.56 2.61 2.29 3.86 3.81 4.13 2.45 5.65 4.66 41.9^8 .,. 4.64 2,6 0.118 0.558 0.594 0.436 1.5 8.84 1,74 1,24 0.87 0317 0568 0.291 0.178 0.503 2.76 2.91 2.81 1.33 1/29/2003 1 of3 Tab 3.10 Consent Order T&PJ(IS ASH02l"7l5 EID639&47 Table 3.10 Summai'y of Analytical Results; C*8 in Surface Water DuPont Washington Works Facility Washington, WV ' '"' ' ^.'Sampla'' OUTLET 003 (Cont.) OUTFALL OOS OUTLET 007 OUTLET 105 Date 1/17/2002 1/17/02 (dupl 12/20/2001 11/13/2002 10/18/2002 9/246002 9/24/02 MW) 9/27/2002 7/23/2002 6/26/2002 5/20/2002 5/17/2002 4/16/2002 3/19/2002 2/6/2002 1/17/2002 12/20/2001 12gO/01(dupL^ 11/26/2001 10/26/2001 8/19/2001 8/30/2001 7/11/2001 6/14/2001 S/31/2001 4/11/2001 3/21/2001 2/14/2001 11/136002 10/18/2602 10/18/02 (dup) 9/24/2002 8/27/2002 7/23/2002 7/23/02 (dup) 6/25/2002 5/20/2002 4/182002 3/18/2002 2/5/2002 2/S02(dup), 1/17/2002 12/20/2001 11/13/2002 10/18/2002 9/24/2002 8/27/2002 7/23/2002 0.8(11(1/1) 0.956 vt9y 0.713 18.1 12.1 4,64 5.02 ....^'..1"9,2i 17.9 98.6 6$.7 3.8 9,26 141 137 31.4 35.2 915 65.7 2.86 2.16 120 7A 1.43 4.31 199 183 8.88 0.261 0.209 NQ (<O.OS) 0307 O.S97 0.844 0.284 0.49 O.S87 0.483 0.32 0.339 0.871 1.98 10.5 54.6 3.69 6.73 34.7 1/29/2003 2 of 3 Tab 3.1.0 Consent Order T&F.xte ASH021716 BID639948 Table 3.10 Summary of Analytical Results: C-8 in Surface Water DuPont Washington Works Facility Washington, WV " " -:;^'Santpte OUTLET 105 (Coni) Date C-B{uafl) 6/2S/2002 A3.n0o0 5/20%002 8.27 5<2(M02(dup) 5.18 4/16/2002 18.9 3/19/2002 13.2 2/5/2002 14.8 1/17^002 7.53 12/20/2001 9.7B -- -flLl-..mha^Vl-1 ta 'Barton 90 ftfbuPont (2003b) 1/2W2003 3 of 3 Tab 3.10 Consent Order T&F.xte ASH021717 EID639949 ASH021718 EID639950 ASH02171& EID63&951 Table 3.12 Outfall 005 C-8 concentration (ug/1) DuPont Washington Works SamplalO WWK-Z- OUTFA11M5 WWK-Z- OUTFALL 005 WWK-Z- OUTFALL 005 WWK-Z- OUTFALL 005 WWK.Z. OUTFALL 005 WWK.Z- OUTFALL 005 WWK-Z- OUTFALL 005 WWK-Z- OUTFALL 005 WWK-Z. OUTFALL 005 WWK-Z- OUTFALL 005 Date e/M2002 W25/2002 6/26/2002 6/27/2002 7/1/2002 7/10/2002 7/11/2002 7/12/2002 10/16/2002 10/17/2002 C'8U8/L 26.7 17.9 47.7 78.3 13.6 37.8 239.0 12.5 141.0 18.0 1/29/2003 .1of1 Tab 3.12 Consent Order T&F.xls ASH021720 EID63S&S2 ^^ Remote User Remote User 11Job 183 007/16J04 10:22 AIVI Table 3.13 Summary of C-8 in Kroundwater Public Water Supplies, West Virginia and Ohio Dupont Washington Works Facility, Washington WV Located PflrHeroburg.WV Btfprt.OH BteimwhassBK Island WV Littis Hocking, OH SamplalD PPSOPT PPSOAT PP8DA.T PPSDRANY1 PPSDRAMY1 PPSDRANY1 PPSDRAW2 PPSDRANY3 PPSDRAMY4 PP8DRANY5 BB-PSDAT BE1.PSDAT aapSDAT Bapsppwi BELPSDPW1 BEU'SDPWZ BB.PSDPW2 BEl^SOPWZ BELPSDPW3 BEtPSOPW BEUPSDPW4 BBPSOPWl BBIPSDPW4 BELPSDPWS BEU'SDPW BaPSOPWB BB.PSPPWS BLENITm BLENITW BIENIW16A BLENISLEP81 LHP8D1 (.HPSDI LHPSD1 IHPSDl IHPSD1 LHPS01 LHP8D1 LHPSD2 LHPSD2 IHPSDZ mpsoe t-HPSDZ WPS&2 IHPSD2 t-HPSD2 LHPSD2 l-HPSb3 LHPS&3 SaniplSaio 36ia02 arenooz 4050002 3/W2802 a/s^xe 4/28(2002 3/6G002 3/6<Z002 3/6/2002 3ffiB002 WWKQ. 3%5BW2 4/23^002 ZffffiBOZ 3f25%B02 WWHH6. ynws 3K&2002 3G5B002 ' 4/23/2002 2ffrat02 3/25^002 4/23<02 2/7(2002 3/25/2002 '1/23/2002 4/23(2002 2/21/2002 2/21ffi002 2/21/2002 1/30/2D02 12/202001 1/21/2002 2/22/2002 3/202002 4/23/2002 azi/ztxe 10/16/2002 12%n/2001 12ttW2001 iQiaooz 2026002 2BZBOC2 3KBffD02 4/23/ZW2 8CT/2002 10/16B002 12^2001 1&1/2002 JfeBugfl NQ(<;0,OSO) NQ(0.060) NQ(<O.OSO) 0.0663 0.0689 0.0746 ND(<0.010) ND(<0^01 NDt<0.010) NDMA10) o.oaie 0.113 0.12 0.09&5 0.13 NQ1<OA50) WH<0.050) NQf<O.OSO) 0.141 0.12 0.101 0.133 0.114 0.107 0.103 0.107 B.111 ND(<0,010) NQ(<0.05D) 0,316 0.16S 1fl2 1,72 2^7 2.M 2.02 3.65 3.41 3.72 3ja 2.97 2.03 2.07 3.31 3.4 4.26 3.B8 0.844 0.744 COfiBnc4 Before Treatment Sample After Tfeatrrieni Sample After Trealfflwil Sample ProluriionWsB dupjicate ProdudlwiWel) ProAiclImWell PfoductenWrii PiwlMcfonWstI Ptotiuaion Wll Ntw Trwimsnl Sample After TfealtnenI Sainpit; After TrealniBnt Saffi(ihi ProBurtonWSli PtCTluctionWOII PnxlucllonWeil duplicate ProtfuctlonWBII pTOJucUgoWdl PmdutllMtVltell pnxlucfiwWell ptBdufltliinWat Production Wtill PfoduclionWel) PrDducttonWOII PtoducllonWell duplicate Ttslwel Toalwflll Teslwel Drtniting SupplyWell ProtfucBMiWell ProducUonWeH ProducBon Well ProAirtlonWel) Pnduaon Well PttductonWell Production Wdll Production Will dupllcale production Wel ProihictlMiWel ProducHonWell ProtlucllanWcll PftMiticSonWl Production Well PioductionWEll pfotfuclionWell PfddtlCtlonVKell 1/29/2003 1of5 Tab 3.13 Consent Order T&P.xte ASH023L721 EID639953 Table 3.13 Summary of C-8 In Groundwater Public Water Supplies, West Virginia and Ohio Dupont Washington Works Facility, Washington WV loc.iflon UUteHocMnB.OHtconl.) GenewlBeddc.W/ LiibecJ<,WV Si>nipl!D LHPSD3 LHPSD3 mp8D3 LHPSD3 LHPS03 mp5D3 LHPS05 LHPSD5 LHPSD6 LHPSD5 LHPSDS LHPSDS mpsos LHPSD8 mPSDEPOOl IWSDEP001 mpSDEPOO! LHPSDEP001 LHPSOTWI WSDW1 mfSfTOW LHPSDTWO tHPSDTWH WPSDTWH LHPSDTW12 WPSDW12 IHPSDTWZ I.HP8BTW2 WPSOTW LHPSDTW3 1.HPSDTW4 1HPSDTW4 LHPSt)TO4 LHPSOTW4 LHPSDTW4 LtPSDTW LHPSDTW6 IW8DTW6 LHP8DTW LHPSDTO LHPSDTW9 IHTORCHBS BAR'n-errec 338B?TA eEWEU.3 6EWEU.3 OEWEU.3 GEWajLS LPSDAT LPS&AT 8inpI*D.lt> wanaaa. 3f2BQ002 4f23tt002 WsMWSt 1M16C002 10/16tt0&2 lazoaool iaiaoM wiwa 2ffi2/ZOl)2 3(26/2002 Aawiwi WiVWft 10rtS2fl62 MSSKWS MB/2002 4C2B02 0/1B20D2 1Q220C2 9/21/2002 KZ1BCB2 ?1/2002 iffiiaooi SQ1/2002 1/2ltt(>2 ?1(2002 1/22/2(102 801/2602 1/282002 f)/21B(H)2 1/22B002 3/28ffiC02 4/23/2002 8^1/2002 1W16S002 801/2(102 1/220)02 Bttl/2002 W21/2002 1/220002 9HMW& 1/22/2C02 ia2/zo% 1/22002 1/30002 1/3/2002 2/21/2002 .. ,.,,.,,, 4/260)02 3/26/2602 4/26/20Q2 C4ugn 0.42 O.S27 D.783 0.952 0.495 0.434 7,66 B.22 9.14 S,99 657 6.11 6.09 8,58 1.69 2, 1.93 4.2S 2.16 0.81 1.B 1.1 1.41 1.73 0.758 0.824 0.103 0.081 4.48 4.17 37.1 33.3 28.7 12.3 14.5 S.28 1.79 1.16 1,23 0.364 0.812 1.8S 1.94 1.81 1.78 W ..,,.. 1.75 1.84 0.69 0.652 Gcmnrt PnrtueConWoll PniiJwttcnWBll Prpiiuctitin Well fWtSssSW\ Well Po4wllon Wtill dutllcato pTOhidionWell production Well dwifcale Pioducuonwetl ProducliooWBll ProdwMonWtf ProducBonWal piBtftidionWell WBtcf System Pdnl VteterSysternPoinI Water SystemPoint Water 8yti) Point Test Well Testwil Testwd Test well T66tell TBrtwII ToawBll Teslwflll TtBlwell Test well Test well Test wall Tertwell Test well Test well Test wen Test well Tertwl) Telwll T6stwe ijiipltEdte TsstweD TtttWB|] W^tefSydBmPtiint Watw System Print Water System point Production Well duplicate Ptixlutlten Wen Production Wett AHerTreaiinenI Sample After Treatment Sample 1/29/2003 2 of 3 Tab 3.13 Consent Order T&F-xlS ASB021722 EID639954 Table 3.13 Summary of C-8 In Groundwater public Water Supplie$, West Virginia and Ohio Dupont Washington Works Facility, Washington WV 1001800 Lubeck,WV(a)fit. BdtevBlo Hydra PteiAWV TuppersPlains PSD. OH Samplalt) IPSDAT LPSDAT LPSDWEI-IA LPSDW&LA LP$DWH.LA LPSDWELLA fcPSDWB.l.A LPSDWELLA LPSOWELLB IP8DWEU.B LPSDWEU.B LPSDvreixB LPSDWEU.B LPSDWEU.C LPSDWELLC tpsowaic 1.P30W6U.C LPSDWELLC LPSDWH.LC LPSDWEU.D IPSDWELL& IP50WELLD LPSDwa-LD LPSDWHXD IPSDWEULD LPSDWELLE IPSDWEU-E LP8DWB1.E U'SDWH-LE LPSDWBXE IPSO WELLS IPSDWHJ-F LPSDWEU.F U'SDVffiU.F IPSDWELLF LFSDWEULP LPSDWELLF IPSDWBXF LPSDWELLF BailEVILLELD TPP8DP7 TPPSOPT TPPSDPT TPPSDPT TPPSDAT TPPSDAT TPP8PAT .TPPSDAT 7FPSOAT TPPSOFW1 SuHtAtWt 82W002 WWBIS 1(3Q002 2)21/2002 308Q002 Aseiwa TB4G002 )B;1S2002 221S002 3CTQ002 4/26f2002 7(ffi(XB 10/1B2002 10(2002 ZffliEonz y28ffi002 -taazooz 7/2*2002 iiaa)02 iraaona asicote 3/28/2002 4tt6tt002 7B4ao02 1 (VIS/ZOO? 1/3/2002 2/21/2002 3RaS002 4/2&2002 7/M2002 10/IBttOO?. i/afflonz ZEI/ZOtti a^a^oo? 3/28/2002 406/21)02 7/24/2002 7tt4QOffii 10/15/2002 1/29/2002 2/02002 MSUm 7/23/2D02 10/15/2002 2tB/2002 3/2S/2002 4/24/2002 7B3/Z002 10/15/2002 2/6/2B02 (M>U(jrt 0.6 0553 0.784 0,683 0.7S6 0,936 6.753 0.656 0.61 0.551 0.832 0.443 0.537 O.S92 0.479 0.491 0.471 0.396 0584 0.756 0.725 0.692 0506 6444 O.S17 0.332 1 1.09 1.11 1.02 1,21 1.04 0.313 0.35B 0.362 0.332 0,284 0.283 0.365 NCKO.OSO) 0.372 OJ47 0.24 0.226 0.361 0.35B 0.363 0.246 0.268 0.726 Coimtiontii ABeTTi-wlineiil Sample After Treatineni Sample ProduclknWell -c^ -^"^"^LW Production We PtoductionWell PioduatonWell PwxIudlMiWell PmdudtonWell ProdudlonWell Pr^ucttonWell PiDduaionWel] PicdueMoitWel PttduiSBwWrt ProiludlonWcn ProOuclIOnWell Pfoducton Wall productonWoll Production Wfll ProduaonWelt Productton Well Pfoducllon Well Piiiiluctionweli ProiliitBonWell PtoduclionWell PwlucltonWell Production Well PtwfwtionWell PnductenWBll Production Well Production Well PiciltKtfonWa Production WB]I Production Won duplicate Production Well PraAiaionWeB duplicate ProdudtonWall Miscellsneoua U?B BetofaTfeabnent Sample BisfotB Tftamieni Sample Belnw Tfeatmert Saiwie Beffirti Treatment Sample After Treatment Sample Atef Treatment Sample Alter Trftatnient Saniple Aftsr Treatinert SBinpte Alter TfefltnKifil Sample Production WEII 1/28/2003 3 Of 5 Tab 3.13 Consent Order T&F.xls ASH021723 BID639955 Table 3,13 Summary of C^8 In Groundwater Public Water Supplies, West Virginia and Ohio Dupont Washington Works Facility, Washington WV Location TiippBre Plains PSD, OH icont.) Ravenswooti Municipal, WV Mason CountyPSD.WV RatfnB Locte and Dam, \W VllteOBet Racine, OH New Haven water ttept, m SarnplBlO TPP$DPW TPP5DPW 7PPSDPW1 WSOPW TPP8DPW2 W8DPW2 TPPSDPW2 TPP3DPW2 TPPSOPVtt TPPSDPTO TPP8DPWS TPPSDPW3 TPP8DFW3 TPPSDWt 7PPSDPW4 TPPSDPW4 TPPSDPW4 TWSDPW5 TPPSDPWS WPSPPW5 TFPSDPWS WPSDPWB TPPSDPWB TPPSDPW6 tfVSt/VW TPPSDPWB C6RASIM coR/ffioirr CORBIENPA1 CORWEU.1 CORWOJ.2 CORWEUJ CORW6U.4 CORWEU.8 WSOWiPSW ' WSOHCPSS)^ MASONCPSD1 MASONCPSD2 MASONCPSD2 MASONCPS02 wsampssa MASONCPSD3 MASCT1CPSD3 RAaNELB VORAT VORRV3 VORWEUI VORWEl.U NHPSDAT MHPSDPW1 SannplBt>at WBawa 4iuiwa tssiwa wwaai sawn SRSWW WWW! 7ff3tt002 16M5/2602 2/Btt002 3K51W& 713SatW!i WS2002 W3SOS. 3^5/2002 7/230002 1OT5QB02 wwa Wtsmca 7B3f2602 lo/isecoz zreaooz W25f2002 4<24tt002 7f23tt002 10;15f20&2 3/27B002 3<zreo ?7(2002 %i7120(B 3ffi7C002 awttooa 3/27/2002 3ffi7f2002 1tt9;2002 aa/eooz 4(2a2D02 KZBQQte 307(2002 4050002 1/29,12002 M27(20fl2 4/25COO; K4ffi002 3C66002 3/28(2002 3C6C002 3GNZB02 4/11X2002 4/10C002 oauafi 0,70S 0.702 0.588 0.4BS 0.417 t.327 0.371 0.235 0^55 NQWA50) NQ(<0.flSO ND(<0.010) MD(<0.010( OA734 0.07 O.OS2 0.07? 0^01 0501 0.216 0229 0.649 0.634 0.62 O.B2 0.433 NO(tOA10) NQ(<9.050) ND (<0,010) NDMA10) N^-stt.OW) ND (<D.010) ND(<OWO) ND(<0.010) NQ (til.050) NQ(<O.OBOi NQ(<1),050) O.OS18 0.0936 0.0714 0.0707 0.1BZ 0,063 0.51B NO (<0,010) ND(<0.010) ND (<0.010j ND(<0.fl10) N(<0.010) NQ(<0.oa>) CoffiMAtS ProdMCliWiWBll PnxIwillonWell PtoiluctkmWBl) PtOtlucUonWeli Production Well PiotefcnWel) ProiWtoWell ProAicttonWell ProductonWell ProductionWell PtoiJucBonWell ProdurtKm-Well PiMixatenWel ProAictlonWeB PuitluliltenWell ProductonWBll ProAicHonWell PtoAiciIonWBll pforiucttonWell Production WBII ProdueltonWell ProduaionWel) ProdudloitWtl) PicdualonWal ProclucBonWBll PtcductIonWell AlrSl(l|itarln Air Stripper Oul Blend Alter Treatment PrwiDcliDnWell PiBductlonWel) PrttluctionWell ProducliOnWel) ProducUnilWBll ProducltonWril Production Wen ProUucttoriWBll ProdMcilwiWeg PrtxiuctittnWoB PioduaiMiwrt ProtiuctlonWeB ProduiiHonWel PicducttonWel MiscellaneOtS U6 Wsf Treatrmnt Sample PwiuGliMiWflt ProauctlonWol PmaucltonWBl After Treafcneni Sairpte ProducllonWet 1/29/2003 4 of 5 Tab 3.13 Consent Order T&F.xls ASB021724 BID639956 Table 3.13 Summary of C-8 in Oroundwater Public Water Supplies, West Virginia and Ohio Dupont Washington Works Facility, Washington WV Locirilon Nw Haven Watw Dept., W Wage ol Syracuse. OH VHgto(Pomeroy,OH SanpltIO MHPSDPW1 V08AT VOSAT VOS NORTHS VCNORTH2 vosscxnHre vcsswTHta vowr VOPAT VOPWEU.1 vopwai.2 VOPWBl.2 VOPW&U VOPWBXfl Saii)plE>atB 4/IIM200S 3CT200S UWWS& waism WWS& 3/26ffiM)2 44^2 3t2S12<2 wmwa WMaSKO. WSISBSS 4C4/2002 3/26QCC2 4ffi4f2002 MO s Not OeiettM al w above ttie Bmitol (iBteetlen (100). TTia Bsltd LOD 1$approximate and varies by irisliument and ww <maN0 = Not QwnllllabI*. DelBfited at 9 teel abow the LOD atlfl below lh6 llmtt ol quantmeauon (.00), ABC-8 resulbai'fttepoitedinuflfl. Misc." MiiCetlarou water Usie Is nDl used for drinking. C-flUBft NQ(<(1.050) NQM-OS11 ND(<0.010) NQ(<0.050) M9( t-SBB ND(<!B.010) 0.0656 0.0626 ND(<0.010) 0.0689 ND(<;0.01< 0.0851 CommMib AllerTrwimenI Sampit Afler TrBcibTient SBffipte ' PflducltonW PioducBmWell Production Wisll ARw Treatrnnnl SBrnptp After Treatmiinl Spmple Pw*lfoiWe PipAiaiotiWal PioBuciitmWtl PioduaionWeB 1/29/2003 5of5 Tab 3.13 ConSBnt Order T&F.xls ASH021725 BID639&57 Table 3.14 Synoptic Groundwater Elevations February 2002 and Well Screen Locations DuPont Washington Works Facility Washington, West Virginia Mew ID AC05.MW01 M.10.MW01 A008.MW01 A003-MW01 AR09.MWB1 Measuring Pohit BevattontteBt)1 635.22 631.81 B36.02 632.89 635^7 Old ID TW-E6 TW.W1 TW-4S TW.28 TW-38 fffiiamySaWW 68:6 S7.12 74A3 mst 76.01 AX12.MW1 B35.23 TW.3B 73.81 DOW1W01 F06-MW01 600.67 601.14 m-w 7W-M6 37.8B 38.9 )07'MW01 610,23 TW-M3 49.18 JOWfW K14-MW01 630.21 627.34 TW-20 TW.M4 69.0 66.25 L1B-MW01 698.82 TW-27 78.67 MIMflWOI N04.MW01 627.14 594.48 TW-S5 TW^2 68,9 16-46 N19-MW01 625.87 TWS4 65.95 P08-MW01 629.29 TW.53 69,19 Q04-MW02 S68.76 TW.50 36.71 T13.MW&1 W6WWS U16.MW01 ^ 631.17 638.23 TW-24 'awn TW-25 71.59 79,02 76.8 V09.MW01 628.5 TW.3(p4) 67.3B YOS^WOI B31.16 TW-ES 67.48 Z07-MW02 632.46 TW-22 B7.9 M04-MW01 BS9.95 TW-70 34.4 AA05-MW01 633,32 TW-71 67.71 AB07-MW02 839.02 TW'72 67.41 AE11.MW01 6ZB.B4 TW-74 62.92 E13.MW01 62S.47 TW-7B 64.35 017.MW01 63Z.81 TW-77 73.35 MD4-MW02 695.51 TW-79 13.42 M04-MW S9S.43 TVI-SB 13,93 N04-MW02 595.82 7W-81 13.78 N05-MW01 633.1? TW-82 73.16 P04.MW02 P05MWD2 SB2.3B 631^4 TW-83 TW-84 20.48 71.14 R04.MWDZ 694.92 1W-SS 16.63 S05.MW02 630.64 TW48 71.68 U04-MW01 V09.MW01 596,43 629.49 TW-W TW-C8 t1,97 79.53 WO^MWOI Y1441W01 Z06*)W02 629.9 6WS 829.21 TVlf-89 TW-SO TW-81 70.42 00.1 e,2 207-MW01 z<wawoi 632.98 624.65 TW-82 TW-93 68.97 60.95 AH Measuring Point Bevafcn data Is tfDin Vtrncn surveys In 1689 or 1998. Grufl)datr Elevation (ri>l) S64.49 561.09 S62.57 560.26 581.42 562.69 562.24 561.05 60.41 559.09 556.9S 58.24 578.1)2 559.92 560.1 660.05 561.1 6S2.15 61.73 581.12 563.68 664.69 66S.5S 665,61 685,61 566.02 5$1.12 B59.46 582.B9 581,5 582.04 559.99 57151 590.1 876.39 668.68 583.46 5SB.fifl 5S9.48 562.1S 5(4.01 564.01 563.7 Screen Lorttitin* siteprimaryaquifer ste primary aquifer site primaiy aquifer siteprimary aquifer site primaryaquifer site primary aquifer site primaryaquifer site prtnar^aquifef ^te^rimary aquifer sita primaryaquifer sitepiimaryaquifer site primaryaquifer site primaryaquifer perched water table site primary aquifer sitejmnwy aquifer site primary aquifer sitegrliinajyiguifer site primary aquifer site primary aquifer site primary aquifer sita primary (Kimfer site primary 3tiuif@r siteprimarYaquifer site primary aquifer site primaryaquifer site primary aquifer site primary aquifer site primaixaiyjfer perched water tabte perched water table perchedwater table site primary aquifer perchedwater faMe site primary aquifer lurched water table site prtfnaiYjWter perched water table site primary aquifer site primary aquifer sitejirimatYilquifer site primary aquifer site primary aquifer Isiteprimary aquifer 1/29/2003 1oM Tab 3.14 Consent Order T&F.xls ASH021726 EID63&958 ^. Is 8 1 <B ?"E ffl ' .8 ir 1^ 88 5 s ; -a.' I|Qj; tAe = >_ a .s ^ l8s-a ?il gSl is88 o i B> x-- a R --' 0 ASH021727 EID639959 <-" Tabte 4.0 Monitoring Wdl Construction and Groundwater Elevation Data Local Landfill 1 1 Washington, WV .... . - ParamBters Measuring Point Bevaflon jgee^ maw-4 647.55 Total Depth (feet) Well Diameter (inches) Slot Size (inches) ' 157.1 4 0.020 Screen Length (feet) Screen Interval (feet) 20 710.45- 69&.4S LLMW-fi 796.27 93.08 4 0^20 20 723.18. 703.-18 December-01 january-02 February-02 March'02 May-02 Augiust.2 October'02 682.55 71S.39 715.28 715.31 714.93 71S.52 715.53 718^9 720.41 719.76 722.00 721.52 719.77 7-19.58 U-WSW-9 U-!MW-1t LUAW-12S. '^ - l^^i^.'-.-.e^te LLMW-W LUlSW-ISB 788.54 81,38 4 805.94 87,75 4 764.28 94.94 2 663.83 42.37 2 0.020 0.020 0.010 0.010 20 20 20 20 727.15707.15 738.19 i 718.19 688.34- 641.4S - 68.34 ; 621.46 Grow,idwaierElevaaon (fast) 727.78 728.06 728.01. 728.12 720.67 720.51 720.73 720.90 728,48 728.24 728.10 721.84 722.97 723.01 681 S3 640.42 7S0.80 139.87 2 0.010 15 625.93 610.93 648.29 1/29/2003 1of1 Ta Table 4.1 Summary of Analytical Results: C-8 In Groundwater Local Landfill Washington, WV Sample LLMW-4 LLMW-6 LLMW-9 Date A-Zona 10/15/2002 9/3/2002 5/20/2002 3/280002 2/26/2002 ""T/2W2002 "" 12/13&001 5/16/2001 5/11/2000 siwm S/27/199B 4/11/1986 10/16/2002 10/15/02 (dup) 9/3/2002 S/20/2002 3/28/2002 2/25/2002 1/27/2002 12/13/2001 8/16/2001 5/10/2000 5/19/1999 5/27/1998 4/11/1896 10/18/2002 9/3/2002 5/20^002 3/28/2002 2/28/2002 1/27/2002 12/13/2001 5/16/2001 5/10/2000 S/20/1889 5/27/1998 4/11/1896 c^(ug/l) 79.6 63.5 55.7 47.2 50.2 58.4 54.6 1,40 10 16.2 26 39 19.8 17 13.7 18.6 11.5 10.1 12.2 11.9 3 1.42 1.32 9 IS 0.0669 NQ NQ NQ NQ NQ ND 0.039 J 0.029 0.048 J <;0.1 0.14 1/29/2003 1of2 Tab 4.1 Consent Order T&F.xls ASH021729 EID639961 Table 4.1 Summary of Analytical Results: C'8 in Groundwater Local Landfill Washington, WV Sampte LLMW-10 . LLMW-12B . LLMW-11A Luwr-ifr U-MW-14B ' "''.I' -'^ LLMW-11B Data 10/15/2002 9/3/2002 SttO/2002 3/28/2)02 2/25/2002 1/27/2002 12/13/2001 5/20/1999 5/28/1998 B-Zone 10/8/2002 C-Zone 10/6/2002 10/8/2002 . 10/9/2002: D^ona r 10/8^002 C-8 (ug/1) 0.395 0.357 0.56 0.698 1.12 0.162 0.133 0.15 0.22 0.6658 2.22 6.81 0.488 NQ(<O.OS) J(i?(imatet) value (bi;l<w laboratory quanlllaHonliiril) Nl> Not Detected at or above the limit of OeteCBon (LOD) NO3 Not Quantifiable, Detected at a concenlraficn above the LOD and below the limit (rf quantification (LOO). Note: Analytical method changed as of Noi/smber 2001 {seesSection 2.0 for details). 1/29/2003 2 Of 2 Tab 4.1 Consent Order T&F.xts ASH021730 EID639962 Table 4.2 Summary of Analytical Results: C-8 in Surface Water Local Landfill Washington, WV Sampte OUTFALL 064 (New) OUTFAU-004(01d) OUTFALL 006 (New) Date 11/30/2002 1QQ1/2002 9/30/2002 8/266002 7/1/2002 6/13/2002 6/21/2002 4/29/2002 %6/2002 11/80/2002 10/31/2002 9/30/2002 B/26)2002 7/1/2002 6/13^002 8/21^002 ' 4/28/2002 3/26/2002 2/20/2002 1/24/2002 12/13/2001 8/27/2000 12/KVW9 6/3/WW 6/2/1998 59/1997 4/2/1986 2l'16/1984 11/30/2002 10/31/2002 9/30/2002 8/26/2002 7/1/200Z 6/13/2002 5/21/2002 4/29/2002 3/26/2002 C-a(ugfl) No-flow conditions No-ltow conditions No-ttow conditions No-flow conditions ^ r- 11.2 9.29 (sfo-flowcdhdilfona 14.5 -""14^" . No*ftow conditions No-flow conditions Mo-flow conditions No-flow conditions 11.@ 10 No-flow conditlor>8 15 1.S4 10.9 11.4 No-flow conditions 4.73 i:i----" 3.00 12 13 13 11 No-f tow conditions No-ftow conditions No-flow conditions Notlow conditions No-flow conditions No-flow eonditlona No-ftowconditlona 34.3 16 1/29/2003 iota Tab 4.2 Consent Order T&P.x)s ASH021731 BID 63 9 9 63 Table 4.2 Summary of Analytical Results: 08 in Surface Water Local Landtill Washington, WV Sample OUTFALL 005 (Old)/8S1 OUTLET 101 LM1j(LEachate)/lntet002 Date 11/30/2002 10/31/2002 9/30/2002 8/28/2002 7/1/2002 6/13/2002 5/21/2002 4/29/2002 3/26/2002 2/20/2002 1/11/2002 12/13/2001 9/27/2000 12/1W19&& 6/3/1999 6/2/1998 6/29/1997 4/2/1996 8/16/1994 11/18/2002 10/31/2062 9/30/2002 8/26/2002 7/1/2002 6/13/2002 5/21/2002 4/29/2002 3/25/2002 2/20/2002 1/23/2002 12/iaadoi 9/14/2000 6/3/1999 8/2/1898 11/21/2002 C-8(ugfl) No-flow conditions No-flow conditions No-flow conditions No-flow conditions 32.1 27.3 No-Jlow conditions 40.9 39 .48 1.4 No-flow conditions 13.3 84 6.8 39 41 89 35 76.7 78.6 115 70.3 63 38 40 48.2 36.4 63.1 81.4 82.4 12 16 84 120 Note: Analytical method changed as of November 2001 (see Section 2.0 of DuPont (2003b)tor<3eaBs). 1/29/2003 2of2 Tab 4.2 Consent Order T&F.xls ASH021732 EID639&64 Table 4.3 Summary of On-site and Off-site Exposure Pathways Evaluation Local Landfill ---;... .' .. ;-. .. ..... -^<.a&':;^',As^^^aC^Bi!^iiffiw^i^iitualteB^.t'S^; Human Health Exposure Pathways .- . Ecological Expo 0-8 Impacted Media On-Srte SWMUs/Landfiiled Materials Pathway Assessment (Complete or Incomplete) 1 Comparison to Screening Criteria* -- Pathway Assessment (Complete or Com Incomplete) ( Crite j SOB 1 Laachate Surface Water c ! "! 120ug/)<150t3g/l C c t15ag/i<'150ug/l S C --.. Groundwater . . -- ,, .-...-1 Expoatwe Patiways tor Human and Ecological Re ceptors ..J . . .-- C-8 Impacted Media Off-Site Drinking Water tweiis, Pathway Assessment [Complete {C) or Incomplete ii)] Compaj-lson to Screening Criteria* springs and/or ctstems) . Local C 2,aug/l150ug/l . Non-drinking water (weKs springs and/or cfeteme) - .Eocal. ....... ,, J1-... -.?--.-...- ASL'S'?<1SO "fi^ ..... ..,,. Unused water sources I --.-. ... * Highest valus tn category is compareTtothe screeningcriteria. Screening criteria was estabi ished byCA1Tof240mg/kg Be (surface water), 150 ug/t (or drinkingwater. For complete, all water samples, are compared to the drinking water seresening No comoarison is made for Incomplete exposure pathways. 1/30/2003 tof1 Ta Table 5.0 Summary of Off-site Sampling Program (C-8 Sampling) Letart Landfill Letart. WV : ^SESIDENTIASLAMPLING FOR 1 -MILE RADIUS ift a> Number of homes contacted(1) 48 0 X Number of homes surveyed(1> 46 Number of wells identified<2) 42 a 'S Number ofwelte sampledS2) 30 Number of wells sampled that are used for drinkingwater 11 i m Number of cisterns identified!2) 4 Number of cisterns sampled t2) 0 5 Number of cisterns sampled that are used for drinking water 0 Number of sprinqs identified!2) 0 is Number of springs sampled12) 0 W0. Number of springs sampled that are used for drinking water 0 1 Total number of samples 30 1 Total number of collected samples used for drinking water 11 Note: Field duplicates not considered in sample count. (1) During this InvesttgaBon.homeowners/restdents identified withh the sampling radius were contacted to determine residential water usage. Up to two contacts were attempted at each residence. After the second contact attempt, a voluntary survey was left at the residence. Because not all homeowners/residences to the survey, the number of residences surveyed is less than the number of homes contacted. ^Some water sources (e.g. wells, cisterns, springs) identified during the survey were not sampled. In many cases, sampling of these water sources was refused by the homeowners/resldents. In other eases, the water sources were either not accessible or damaged. As a consequence, the number of water sources sampled was less than the number of water sources identified. 2/4/2003 1of1 Tab 5.0 Consent Order T&F-xls ASH021734 EID639966 wgrgn ITS S?| | 51 St 81 S'jS||'| |^(^1 8 8 15|^|5.|5.|5.|?|QJ^|QJ^|?|?; % saaaq&as^Jqqs. al ^ 5 5 flg9SNm3|ttSS|8SSS II ?5555g5si555i e A 3 3 gg a* dill p 50 1^ in Zd w "1 -- jells 'S S i -.IB- a 8 S y S.-& ars s niS BIi .a? a I1 HI 3|1|5 lu w <i6 85 3 h ? sls^s&a e S ae|8(ss|leepae|9 gi rf- 1^ mw s 5a i5i@N^ a a d-io aTffl s g S i i 'J2 ri| bpSi^ ra e B ^ B a, lr S g-s s. s i tg S z p @11 z " S rt 3 5 ASB021735 EID639967 ! 8 sa H 0 CT 1 sy iy " g . t-> <1 u> o Table 5.2 Monitoring; Well Construction and Groundwater Elevation Data Letart Landfiil Letart, WV r ;-. ZSn^^^^W'; --y-.;..,-..:-^;??^',?'^;;;1?, Paramflters UAW-1SA Measuring Point Elevation (feet) 766^5 Total Depth <feat} (52.35 LMW-14A 766^1 158.72 LMW-2A 780.87 182.17 1MW-8 7SQS9 176..43 LBtW-1'O LMW-11 LMW-13B H.M 734.37 776.21 765,86 7 191.55. 16S.54 192.27 2 Well Diameter {inches) Slat Size (inches) Screen Length {feet} Sievation of Screen Interval (feet) Decsmbsr-OI January-02 Febraary-0'2 Marcli-02 May-02 August-02 4 4 4 4 4 , .0.010 20 0.010 20 0.010 30 0.&10 30 0.010 20 655.10635.10 628.19- 62S.70- 608.^6- 608.19 588.70 679.56 ..^-Sy-ya^t;. 'f:''t'"^!^i'y^. ^^SSiSh NA 822.19 622.23 622.44 622.28 622.44 HA 58Z26 %1.@7 581,82 ?1,97 582.34 562.82 542.82 NA 543.37 543.3S S43.3& 543.3& 543.26 543.35 4 4 0,010 0.010 0 25 20 634.87- 593.59 - 58 809.67 ; 573.59 5 '^^i'"'''1-^- :t'&'.".' NA 619.58 620,70 620.99 621.28 621.52 621.10 582.86 S NA = Instrument (EmitaOons t/29/2003 2of2 Tab '" I i H H o w 1 to t0 isfi s s ! H ^1, 'w st Table 5.2 Monitoring Well Constructioi-i and Groundwater Elevation Data Letart Landfill Letart.WV ..a^';,.-;:' .. Z<j%e^f^^^|^ LMW.1 ILMW-T LMW-8 s UflW-3 iLEiinmwV-B3iMA- 1tBMnnWiMf-saayA^ UBW-4 Measuring Point Novation, (feet) Total Depth (feet) Well Diametar (Inches) Slot Sizs {inches) Screen Length (feet) Elevaflon of Scraen Interval (feat) DacaTntwr-OI January-02 Pebruary-02 Ktorch-02 May-02 August-02 October-02 788.93 31,50 y 770.24 36.73 4 777.08 ' 40.60 4 676.47 30.61 2 647.22 30.87 4 674.79 59.59 4 651.58 28.66 2 0.010 0.010 5 10 9 5 10 5 5 742.43. 743.51 - 737.43 733.51 -^-<-----i 752.62 752.82 752.65 752,10 750.27 751.88 751.02 749.73 752.25 751.87 751.S6 751.16 75148 751.75 745.4&. 736.48 745.04 746.76 745.05 746.24 745.41 744.86 745.43 0^^'^^ 6S0.86- 645.86 628.55 616.55 '"":" "ito'liSdwI'Tyalltmailf' E.<letyviijaJMti* 820.20615^0 627.92 622.&2 lyr1----.^ 64&62 619^2 617.4 628.08 648,19 618.76 616.76 642.79 648,07 618.10 615.37 639.93 848.47 617.61 614.80 643.30 846.74 617.50 6t5.27 643.08 646.53 617,38 615,54 636.02 646.77 617.23 615.84 632.47 NA = Instrument fimitafion s 1C9/2003 1 of 2 T 1/29/2003 Table 5.3 Summary of Analytical ttesuHs: C-8 in Groundwater Letart Landfill LBtart.WV ,,-^-, - -satrtpi, UJBW-1 '^~ LMW-7 LMSv-8 AmVWIS .-----^ 10/14)2002 8B9/2DD2 5/24/2002 3/zwwz aa-yzooz 1RB/M02 12/10B001 7/19*2001 1/31/2001 10M/2000 7/24/ZW 4/3COOO .,l'iai2i%,,,,,., ., 10/21/1999 7/20/1999 5/28/1998 7/23/1M7 4/17/1998 ivwm\ 3/22/1991 10/14/2002 B07/2002 5/24/2002 3^/2002 2/24/2002 166/2002 laiOBOOl 7/2WZ001 101/2001 10/4/2000 7/26QOOO OT/ZOOO .Jff^ffi. 1W20/1999 7ff0f1999 S/28/tSS 7ayi997 4/17/1996 11/22/1891 ' 1^4C002 fl/2W2002 5B4/2002 3ffi9K002 2/23/2002 1/Z80002 12/10C001 7/1W20(M 1/30/2001 10/4/2000 mwwa 4/3/ZOOO 1/13GOBO 10BQ/t999 7/2fl1899 SC8/1999 7/23/19&7 -K17MS88 11/22/1991 Miunn) 2^00 23060 30500 206BO 1S400 29400 24600 8100 91B9 , 10600 B9BO 13fl00 17400 12600 "sszo"" 24000 S100 1700 M 60 300 1B7 667 324 180 488 334 242 ,. ,,,,,.., n,^,?2!3"1 168 211 219 339 """""' ,,., ,, .... . ,.,smsa , 53 15 0.1 '"""------34(i0' """ ' 3100 4020 3S20 2230 3930 3240 1120 2950 2300 2160 2160 2100 3260 1790 .,,,^J??20W00^..-^.,,.. 2200 280 lirf4 Table 5.3 Consent OiaerT&F.xls ASH021738 EID639970 1/29/Z003 Table 5.3 Summary of Analytical Results: C-8 In Groundwater Letart Landfill Letart.WV -" " Sah>p LMW-3 Wsw'm& Date Wl 1(2002 swawt stwjaisi wiisasa WAiwa 1086002 12/13/2001 esjiian NQWC5) Divnosainpla 2270 1760 1920 1700 1520 ''WSAr 'TM liawflM 3BOT891 ,,W11,Kffi..,,.,. 6^6/2002 &21C002 3076002 zaa/axa 1060002 tanaool 11B2/1B91 1000 380 112 Diy no sample 87,6 93,8 822 983 94.4 O.S 3/201991 1.8 9ZeCWftils StOiplB ' LMW3A Date 10/11B002 a/zs/ana SB4/!?OOZ M(uflfl 204 Diy-nosampte 134 3^7/2002 2/23G002 J/Z8<^)2 12/11B001 132 .'^ ir- "' 1"111 "ITI 98.9 100 7aftB99 BOA 11B2/1691 350 3/22/1991 3BO LMW-4 10/<ffiTO2 BKT/2002 ssw 1410 5B1C008 1690 37CH>% 2620 2/23/2002 1/26/2002 1Z/13tt001 -.m ., 3060 ,,.,,,.,,: - 1583 4/30000 272 1/14(2000 172 11B2/1891 830 3^8/1801 690 Dre.ZonaWHs -u5jW sSlph Duto --"" " ' 10/11B002 ,,,,,,,, ^m223-0-....,..- 10/11/02 (dun) 2280 8/27/2002 1480 BOwnaijHurt* 1340 ^1^02 1720 5/21/OZWup)* 1830 307/2002 1810 a7M!A!El 2/23/2002 1650 1460 2G3/02(dup) 1480 1/2&2002 1780 1/26/02 tduo) 1690 lail/ZOOl 7/202001 7/20)01(dUp) 1880 483 5B2 20(4 Table 5.3 Consent Outer T&F.xte ASH021739 EID639971 1/29/2003 Tabta S.3 Summary of Analytical Results; c-8 In eroimdwater Letart Landfill Lstart.WV "Saii^ " Dffi^one Wells IC&nt) Oaf 101/2001 10BCOOO Kyaootdup) 7/25BOO& 1/3/2000 4(3/00 (dup) 1/14/2000 10<2W18B9 - LMW-12 . ijjj^----. LMW44A'^-"""""" loci/roidup) 7/20/1999 7Q3/1B97 9CW1&S4 31994 USaiBfll 3W/1991 W10B002 1W1WZ002 1W10B01B -w-,i^W> IJTO5A psmvus Date ^ 10/14ffi002 8/27/2002 SB^ZO% 3/290062 2/24aOC2 . 1^0002 lanaool 7/18B001 IfflOAOOl iowax 7^aooo 4/3/2060 imaMio 1(1BV1999 ;ffiW19B9 Sf28/1S96 7ff3rt9S3' 4/17/1996 ,aMr'''' 3/1S/19M iiffiais9i 3ffi2/19S1 &a(ucH 615 1W..1 760 goo.j 1100 1020 10% 1750 1700 44S 480 ^ 830 1200 300 ^ bry-no sampis 510 ^4 .; ^^i'M 931 676 922 717 714 740 TOO 242 423 24B Z7S 306 453 370 350 TOO 460 480 276 260 83 SO SiKDpla LMW-9 UWV-10 PonBW*ni 0( KVKQ002 aa7/%iia 5RWW2 WQfiWZ 2/24/2002 1/280002 l2rt1ff001 17130000 5/28/1MB naiB9i 3601991 10/17/2002 acaoxB s/zieooz MluaW 15.1 10.8 20.7 14.6 14.9 18.1 16.8 9.4 30 ,,.--. ,,.,,,2'f,,,, 25 -.,, InslniffionlBltti probkinni-Not $snlplB(t Pump pfobtemfi-Nol sampled 0.298 3(ir4 Tabia 5J Consent OrdwT&F.xte ASH021740 EID639972 TabteM Summary of Analytical Results: C-8 in Groundwater LBlart Landfill Letart.WV '. , ' ^ '^ifW LMW-10(Confc) LMW-lt (-MW-T3B LMW-14B ^.^r^y^.----,. UHW.8 P-Zon*W*D Dite aizreooz 2B3/Z002 IBSffl^ iz/isaw 10/14/2002 8/27/2002 5Qiaa)2 3<2B/2002 ZZO(B 28/2002 I^UffiOOl iw-ioaooa lo/ioaooa Uod.rMon.Wdb "-^Ditf1^11 lttl2^ a/zazooz 22002 aZzeooz MQttOOZ 1602002 laidfiool 10/7/1692 C41<Uflfl) 0.138 0.126 0.133 0.134 0.121 e.osa 0.069 0.11& 0.112 0.159 0.128 0.0956 1BS " ""a1!------. ^""'aSo^'--'" 0.479 0.715 0.631 0.617 0.$75 0.846 0^ J s estimated value (below tahorabfy quantltaliDn llmll). Nole: AnalyBcdmElhod changed EB Df Nftwntftr 200) (ico SCt-lion 2.0 of DuPont (SOOSbl)o delans). ' tWWeM dutWcaSisfvaluw wwa pwiloutly teOwrtBnIly ornlBtd ftwi fte ttbtet. V29/2003 4 Of 4 Tabte 5,3 Consent Ordor T&P.xla ASH021741 EID639973 1/29/2003 Table 5.4 Summary of Analytical Results; C"8 In Surface Water Letart Landfill Letart,WV Sampte 002((.EACHATE BASIN) 003 STORMWATERRUNOPP RT 33 STREAM BR1NKERRUN Date 11/25/2002 10/31/2002 W27/SW2 8/30/2002 7/30/2002 8/28/2002 5/30/2002 4/30/2002 3/28/2002 2/19/2002 iaa/2002 12/14/2001 11/27^001 7/20ffi001 7/^2000 4/3/2000 1/14/2000 10/21/1989 11/300)02 WMW2 9/27/2002 8/30/2002 7/30^008 %e<2002 5/30^002 4/30/2002 3/28/2002 2/1W2002 1/2B20Q2 12/14/2001 8/27/2002 10Q1/2002 M7/2002 eraottooz 5/30/2002 4/30/2002 3/28/2002 2/18/2002 1/25/2002 7/20/2001 7/31/2000 7/20/19&& 7/23/19B7 4/17/1986 10/14/2002 c-8(uon) 939 645 4.52 20EO 1410 Not Analyzed* 1630 443 131 365 50.1 38.1 53.2 159 1350 1900 920 3240 No-Flow Conamons No-Plow Conditions 0.17 No-Flew Condition? No-Ptow Conditions Not Analyzed* 0.282 0.0653 0.19B NO-PIM Conditions 0.148 0.39 80.9 2^3 2^4 No-Flow Conditions 1.87 0.84S 1.26 3.92 1.9 2.01 0.573 2.23 2 1.8 0.0612 1of2 Table 5.4 Consent Order T&P-xts ASH021742 B1D639974 Table 5.4 Summary of Analytical Results: C-8 in Surface Water Lei.irt Landfill Letart, WV . -Sanipte CAPfWNOFF Date W2S/2002 10(31/2002 8/300002 6/2S/2002 5/30/2002 4/30/2002 3/28/2002 2/196002 1/25/2002 c-acwn) 85.1 102 No-Flow Conditions Not Analyzed* 371 279 Not Sampled No-Flow Conditions 119 lole: Analytical method changed as of November 2001 (see Section 2.0 of DuPont (2003b) for (ieteils). ' Sarnples were taken at the respective surfacs water locations. However, due to an error by the courier, the samples arrived at the lab warm and were not analyzed, 1/29/2003 2 Of 2 Table 5.4 Consent Order T&F.xls ASH021743 EID639975 TabteS.5 Summary of On-site and Off-site Exposure Pathways Evaluation Letart Landfili Letart, WV " e ^ ^ r w y ^ <'-Expo<u. Human Heaith Exposure Pathways ScoloflicaigxposM Pathway Assessment Pathway Assessment n-Stte (Complete or iCSW-aMImUsp/aLcatnecdBMaieeddKiateterids incomplete)______ wLea.ch.-a.t_e' Surface Water Qroundwater ...J-- ^_ ^L^. 'Comparison to Screening (Complete or ICriteria* i Incomplete) |_ _,' '~"Z'.- ~^~.. ___ _ _,, _ """ h_""*^&ual^l56'T^" ' C"' L "~371u@i/i>156ug/l ""}" C ' ''- \" "" '." \ ' i" Exposure Pathways for Human awS Eeoiogicai Corripari 'Criteria* "' '3 ReesDiare P _ a t h_w.,a_y ^&s._8e,s_s_menf j [Coraptete (C) or Coinparieon to Screening (yinyaeted Media [Off-SllBf ' """ ""~~ ' '"""" tneomplste {!)] Criteria* i.DriritlnaWaterWelte-Letart j ':Norhdinl<ingWater"Wtate- !'"""'" C __ . -.,o13&u.8fl.<<.150u9/l---1 jLetart "[Unused_'w_ate_ r s__o_urc.e.s.'.-."."."i'. .... ..._J3 _...,,. N0(<p.eso) iw ygfl 4Letart lOhto River water 0.128 ug/l 150 ug/l < Highsst value in calegoy is compared to the screening criteria. Screennig criteria was established by CATT of 240 mg&g for s Ufa {surface water), 150 ug/1for drinking water. For complete exposure pathways, sS water samptes are compared to Ihe drinlwig to be consefvative. No comparison is made for incomplete exposure pathways. " Highest C-8 cwcscvssSon (stocathe'fanidfillcap installation 'tn ^112001) te shown. ....... . . '. ........ .. 1/30/2003 tofl Ta Table 6.0 Summary of Off-site Sampling Program (C-8 Sampling) Dry Run Landfill Lubeck, WV 'RESIDENTIAL SAMPLING FOR 1-MILE RADIUS 8 E Number of homes contacted(1) 75 0 ae Number of homes surveyed(1) 64 Number of wells identified(2) 41 w 1 Number of wells sampled(2) 37 Number of wells sampled that are used for drinking water 13 V) Number of cisterns Identified(2) 17 1 Number of cisterns sampledt2) 8 u Number of cisterns sampled that are used for drinking water 1 m Number of springs identified<2) 8 0 e e Number of springs sampledt2) 8 B. w Number of springs sampled that are used for drinking water 1 Total number of samples 53 Q. S) Total number of collected samples used for drinking water 15 Note: Field duplicates nol considered In sample count. (1) During this investigation, homeowners/residents identified within the sampling radius were contacted to determine residential water usage. Up to two contacts were attempted at each residence. After the second contact attempt, a voluntary survey was (eft at the residence. Because not all homeowners/resldences to the survey, the number of residences surveyed is less than the number of homes contacted. ^Some water sources (e.g. wells, cisterns, springs) identified during the survey were not sampled. In many cases, sampling of these water sources was refused by the homeowners/resldents. In other cases, the water sources were either not accessible or damaged. As a consequence, tha number of water sources sampled was less than the number of water sources identffled. 2/4/2003 1of1 Tab 6.0 Consent Order T&F.xls ASH021745 EID639977 TABLE 6.1 Summary of C-8 Analytical Results In Qroundwater and Surface Water (ug/l) Dry Run Landfill (Off-site Wells, Springs, and Cisterns < One Mile Radius) Lubeck, WV Sample ID OS.ABBOTTRL OS.ABBOTTBL 08-ABBOTTS 08-ABBOTTS OS-ANDERSOWD 08.ATKINSONJ2 OS*ATKINSONJ2 OS.ATKINSONM OS-BAKErM 08-MOPKINSKE 08-HOBNBEGKJW OS-MORRISONM OS-NICHOLSONDH 08-PAWEFUl 08-8HIEPHERDM OS-WESTPROOKIM OS-SEEBAUGHR OS.NICH01.80NDH2 r^-^-vs Sample Date "s/i ia/n%ooi ^11^002 0.0606 NQ(<;0.05D) 12/12/2001 0.22 '1/11/2002 0.422 1&13/2001 N0(0.010) 1/9/2002 0.14S 4/1'%002 0.564 18/1 %001 N0(0.010) l2/l4ffi001 12/11/2001 0.338 N0(<0.050> 12/13/2001 ND (0.016) WIW& 12/11^001 ?(0.010) O.OS05 12/10(2001 0.177 2/4/2002 NO(cD.050) 12/12/2001 ND (0.0)0) 2/26/2002 SM/axa 0.273 0.242 Comments DrinkingWater Crinkihg Water Drinking Water CWiKinBWater Drirtklna Water OrlnltinBWatw Dunking Water Drinking Water Ddnking Water Drinking Water Drinking Water DrinkingWater DrinkingWater Drinking Water Drinking Water Drinkingwaier DrinkingWater DtinlilnB water !?Brnpl6 % ^-., Wel Well WBI Well Well We) Well Wel Wel Wel Wel Wel Well Wel Wel Well SKI"S .. -- CIsterr OS-ATKINSOMJ1 1/9/2002 ND (0,010) Misc. 08.BAKEBHK2 2/20/2002 NQ(<O.OSO) unused 08-CHANBYe 2/l'iaote 0.164 Unussd OS-COBBAJ 12/11/2001 0.0839 Misc. 08-OOBBAA? 1/1S/&OIK ND (0.010) Unused 09.DAV18A2 2/13/2002 NQ(<0.050) Unused OS-BniENERDI a/ygooe N0(<0.080] Misc. OS-SR08ED g/ISSOOg ND (0.010) . Unused OS41ARHISRE 12/12/2001 N0(0.010) Unused OSWIWiWOS 03-WPeWEU.g 13/12S001 1/26/2002 0.3S4 ND (0.010) Unused Unused 0&-JONESOR OS^UFMAND 1Z/13/2001 1/11/2002 0.0614 N0(0,010) Mte. Unused 08-I.OBBIN&1 03-ftOaEHTeDR a/iaaooa 1/18/2002 0.078 N0(0.010) Unused Unused DrinkingWater (highlightedin bold bins) Indicates human consumption. NorMlrinkIng Water uaea Include livastock watering, gardening and any other new human comumpfon water usca. ND B Not Detected at or above the limit 01 detection (LCD). The llst^LOD Is approbate and varies by iTWtnjment and werlirne. NQ Nol QuantKlablB. Detected at a level above I>IB LOO and below tha limit 01 quantification (LOO). AH0-8 resurts are reported In utj/t. MteC-s Miscellaneous water use Is not used tor dllnklngData higMghted in yellow are results {or water sources tocoted in the one-rnilB radius lhat nun lesampled during the tso-irite radius sampling went Woll wrii Wall Well Well Well Well Well Well Well Well Well Well Well Well 1/29/2003 4:18 PM 1ol2 Tab 6.1 Consent Order TaF.x)$] ASH021746 EID639978 TABLE 6.1 Summary of C-8 Analytical Results In Groundwater and Surface Water (ug/l) Dry Run Landfill (Off-site Wells, Springs, and Cisterns - One Mite Radius) Lubeok, WV Sample ID OS-8HEPHERDP OS-VANDYNEHB OS-VANDYNEHR OS-VANDYNEHH1 08-WHITEEE OS-WIGALB OS-WIOALR1A OS-WIQALCA OS-WINTCRSJ OS-WRIQHOE DUPONTDRe DUPONTDR3 0$.ATKINSONJ3 OS-GAMPQ3 08-CAMPQ2 OS-DOWI.ERB8 OS-DOWLERE2 OS-RHODEBR os-sesBAuaHV 0$-TeNNANTilD OS-CAMPQ1 OS-DALEL OS-DAV18A1 03.DOWLERE1 DUPONTDR3A OS^NENERDS OS410PEWE1L 1 OS-MOYERSV samplBBate 12/14/2001 1!2/13ffi00) 12/13/2001 1/11/2002 2/20/2002 1/14/2002 1/22002 -1/3/2002 1&t1ffiM1 4/29/2002 1/2/2002 V&ISW& 4/12/2002 2/2W2002 2/2B&002 1/2affi002 l/2a2 2/4^008 826/2002 2/8/2002 S/2eff002 wsfsxa 2/6/2002 i/awsooa 1/28/S008 zs/zooa i/iiiftoos z/2a%ob2 UB/I NQ (<0.050) N0(0.010) ND (0.010) 0.694 N0(<;0.050) NQ(<0.060) 0.127 NQ(<0.05) 6.166 0.838 0.68 Commenu MiBC, Unused duplicate VfrnsuS unused Unused Unused UnuSSd Misc. Utwea Unused Unused 0.825 0.0988 0.081 0.347 055 0,0748 0.278 0.107 Non-dilnlting water Water Cattte Water Cattle Water Cattle duplicate Misc.. Water Catlla Unused Unussfl 0.330 0.64 0.446 0.307 0.175 0.409 0.743 0.974 MISC. MISC. Unused Misc. Unused Misc. Unused Unusad ryp* Well Well Weil Well Well Well Well Well Well Wall Well Well Sprinc Sprint Sprini Sprint Spring Spring Sprint Sprin( Cisleffi Ctetem Ctetew cistern cistern cisteir CIstem Cistem DrtnWngWater (highlightedin bold blue) indicate? human consumption. Non-drinking Water uses Include livestock watertnB, gardening and any ether non-human eonBUrnpBonwater uses. NO a Not Detecled at or above the limit or detection (LOP). The BslBd LOD Is approximate and varies by Instrument and wer lime. NQ No( Quantifiable. Detected at a level abwe the LOD and below the lWtof(|uanllteaoit (LOO), All C-8 results are reported in ug/i. Misti, = Miscellaneous water use is not used tor drinking. 1/29/2003 4:18 PM 2of2 Tab 6.1 Consent Order T&F.xls] ASH021747 EII)639&79 Table 6.2 Monitoring Well Construction and Oroundwater Elevation Data Dry Run Landfill Lubeck.WV Zone Parameters Measuring Point Situation (feel) lotel Depth (feet) Well Diameter [inches) Slot Size (inches) Screen Length (fc6t) Screen Interval (feet) December-01 January "(i2 Pebniaiy-02 March-02 May-M AuguEt-02 October.02 Monitoring Wells OvortmniM) A-Zona DRMW-6A D(WIW-12A DRWW.12B ORMW.13A DRMW.21A DRMW.16B DRMW.17B 744.46 11.89 2 732.41 17.17 4 732.85 20.24 4 722.57 13,33 4 707.62 19.79 2 782,98 61,81 4 853.58 127.09 4 0.010 737'.B1 738.29 738.28 738.75 738.23 735.61 738.92 0,010 5 720.24 715.24 727.30 728.50 727.9& 728.89 728.S7 725.51 728.91 0.010 0,010 0.010 10 722.61 712.81 5 714,24. 709.24 10 697.83687.83 GrountiwaitarElBvaHoni(feet) 728.11 729.14 728.70 729.58 729.67 726.24 72S.S4 714.35 716.9T 714.16 716.6B 718.70 713.62 713.97 708.00 0.010 20 751.37731.57 736.49 0.010 20 746.47726.47 737.19 DRMW-18B 925.87 202.05 4 0.010 20 743.82723.82 787.47 ' .^" , Monitoring Wpite Zona A'ZOft6<eon'l) B-ZOAA Parameters Iteasuring Point Elevation (feet) DRMW-ISB DRMW'20B DRMW.12 881.99 868.79 733.1 DRMW-13 722.88 lotal Depth (feet) Well Diameter (inches) Slol Sbo (Indies) Screon Length tSSl.., Scrtwri Interval (twit) 151.78 4 0.010 20 7S0.23. 730^3 136.41 4 37.82 4 37.84 4 0.010 0.010 0.010 20 752^8732.38 15 710.28. 895.28 15 700.14886.14 (SroUndwatBr Elavfatlon(feQ DRMW.18 C.ZOTO DRMW-21B AbwA- Zona DRMW-14 7X28 48,60 707.67 177.20 838.08 239.81 2 4 10 0.010 0.010 NA 20 20 NA 705.68- 550.47- 685.68 S30.47 NA 3ecember41 January-02 ^ebruary'oz March-02 May-02 August-OS OcSober-02 7S0.94 752.95 724.40 725-25 725.40 7ZB.74 725.99 723.65 723.54 711.81 712.17 711.46 71241 712.54 710.65 711.85 716.10 718.50 716.33 717.02 716.88 715.82 716.02 613.01 754.09 757.99 754.87 755.45 755.12 755.31 755.13 1/29/2003 lof1 Tab 6.2 Consent Onler T&F.xls ASH021748 EID639980 Table 6.3 Summary of Analytical Results: C-8 in Groundwater Dry Run Landfill Lubeck.WV Sample DRMW-6A DRMW-12A DRMW-12B Date | Overburden 10/9/2002 8/28/2002 6/22/2002 3/30/2002 2/20/2002 1/27/2002 12/12/2001 7/20/2000 7/21/1999 5/26/1898 7/22/1897 4/10/1898 10/9/2002 8/28/2002 5/22/2002 3/30/2002 2/20/2002 1/25/2002 12/12/2001 7/19/2000 7/21/1999 5/26/1998 7/22/1997 4/10/1S96 10/9/2002 10/9/02 (dup) 8/28/2002 6/22/2002 3/30/2002 3/30/02 (dup) 2/20/2002 1/25/2002 1/28/02 (dup) 12/12/2001 7/20/2000 7/21/1989 6/16/1998 C'8(ug/l) 1.13 0,785 1.24 0.843 0.822 0.824 1.04 0.212 0.098 0.27 0.36 0.19 0.181 0.088 0.0832 0.0786 0.125 0.168 0.158 0.128 0.081 J <0.10 <M <0.1 0.268 0.242 NQ NQ NQ NQ NQ 0.07S .J^?5 0215 ,.. ,.., N0(0.029) 5.4 <0.1 1/29/2003 1of3 Tab 6.3 Consent Order T&F.xte ASH021749 EID639981 Table 6,3 Summary of Analytical Results; C-8 in Groundwater Dry Run Landfill Lubeck. WV Sample DRMW-13A DRMW-21A DRMW-16B DRMW-17B DRMW-18B DRMW-19B DRMW-20B DRMW-14 DRMW-12 Date Overburden 10/9/2002 8/28/2002 5/22/2002 3/30/2002 2/20/2002 1/25/2002 12/12/2001 7/20/2000 7/21/1999 5/26/1868 7/22/1997 4/10/1996 4/10/1996 (dup) 10/9/2002 A-ZonaWslls 10/8/2002 10W2002 io/mdo2 10/7/2002 16/8/2002 Above A'ZonoWeiis loMiySiT 8/28/2002 5/22/2002 3/30/2002 2/20/2002 1/27/2002 12/12/2001 7/20/2000 7/21/1999 6/16/1998 7/21/1997 4/10/1988 IB.ZOIW Wells 10/9/2002 8/28/2002 5/22/2002 3/30/2002 2/20/2002 C-S^ug/l) 6.68 5.14 2.31 4 3.73 5.97 6.4 9.6 0.070 J 8.7 15 8.2 11 0.27 NQ05) 0.1S8 ND(<0.01) RQ(<a0.05]i NQ(<0.05) N0(0.05) NQ NQ NQ NQ NQ NQ 0.115 2.5 0.1 <0.1 <0.1 " 0.109 0.0626 0.0817 0.0929 0.11 1/29/2003 2(rf3 Tab 6.3 Consent Oi-tier T&P.xls ASH021750 EID639982 Table 6.3 Summary of Analytical Results: C-8 in Oroundwater Dry Run Landfill Lubeek.WV Sample . Data C.8 (ugrt) B-Zono Welts (Cont.) 1/25/2002 0.116 12/12/2001 0.086 7/19/2000 0.16 7/21/1999 0.134 5/26/1998 7/22/1997 4/10/199B <0.10 <0.1 <0.1 DRMW.13 10/9^002 8/28/2002 20.9 , ^ ., ....... ,.,,,, 8/2B/02(dup)* S/22/Z002 14.6 16.9 3/30/2002 12.6 DRMW-13 (Cont.) 2/20/2002 11.5 1/25/2002 - 16.5 12/12/2001 9.86 " ~^ DRMW.15 7/20/2000 7/21/1999 5/26/1998 7/22/1997 B-Zom Walls 10/18/2002 8/28/2002 9.8 3.6 A!iL.,, ,, , 7 4.92 3.99 5/22/2002 $ 5/22/02 (dup)* 3/30/2002 2/20/2002 4.68 4.81 3.68 1/27/2002 12/12/2001 7/20/2000 4.35 4.94 0.763 7/21/1999 ; -- - - ----- ----- e^oniWIS' "~ DRMW-21B 10/90002 0.263 NQ (<0.06l ND=NotDetedetlatorabovfrtfieJimitofdete6Uon(LOD). rhe listed LOD ts approximate and varies by Instrument and over time. NQ = Not Quantiflabte, Detected ar quantification (LOQ). I a estimated value (below laboratory quantltatlon limit). Note: AnalyBcal method changed as of November 2001 (see Section 2.0 of DuPont (2003b) for details). * Analytical duplicates' values were previously Inadvertently^mlttec) from the tables. 1/29/2003 3 of 3 Tab 6.3 Consent Order T&F.xls ASH02t751 EID639983 Table 6.4 Summary of Analytical Results: C-8 in Surface Water Dry Run Landfill Lubeek, WV ' " Saffipte OUTLET 001 OUTLET 003 OUTLET 004 Date 11/21/8002 W/30/2002 9/30/2002 8/30/2002 . 7/31/2002 7/1/2002 6/28/2002 5/28/2002 4/24/2002 3/25/2002 2/2S/2002 1/28/2002 12/12/2001 10/3/2000 ' 12/29/199& 8/19/1998 4/8/1998 11/30/2002 10/30/2002 9/30/2002 8/30/2002 7/1/2002 8/28/2002 5/2a/2002 4/29/2002 3/26/2002 2/25/2002 1/28/2002 12/12/2001 11/30/2002 10/30/2002 9/30/2002 8/30/2002 7/1/2002 6/280002 5/28/2002 4/27/2002 3/26/2002 2/2S/2002 1/28/2002 12/12/2001 G.8(ua/l) , 84.6 81.7 No*flow conditions Noflow conditions No-flow conditions No-flow conditions No-flow conditions 30.8 41 71.6 43.9 41.8 No-flow conditions 31.5 68 17 8B No-flow conditions No-flow conditions No-flow conditions No-ltow conditions 28.3 No-flow conditions No.flow conditions 20.1 6.77 No-Row conditions No.flow condiUons No-flow conditions No-flow conditions No-flow conditions No-flow conditions No-flow conditions 0.7 No-flow conditions No-flow conditions No-flow conditions 1SB No-flow conditions No-flow conditions No-flow conditions 1/29/2003 1 of 3 Tab 6.4 Consent Order T&Fjds ASH021752 EXD639984 Table 6.4 Summary of Analytical Results: C-8 in Surface Water Dry Run Landfill Lubeck.WV SSAlpIft . PROPERTY BOUNDARY STREAM SAMPLING POINTO (88-1) STREAM 8AMPUNO POINT#2 (8S-2) Date C-(U||A) 10/30/3002 mows 5/28/2002 4/240002 3/25/2002 2/25/2002 1/28/2002 12/12/2001 10/3/2000 3.8 No-flow conditions 9.41 6.69 22.8 3.81 11.1 3.99 10.3 12/29/1999 39 7/14/1998 4/9/1896 0.88 9.9 10/30/2002 8/30/2002 - ------N^o.J-f.lo8w3.c,ond, it,i.ons . 5/28/2002 4/24/2002 3/25/2002 2/25/2002 1/28/2002 12/12/2001 10/3/2000 1.63 0.932 1.08 0.85 0.893 1.19 0,788 12/28/1989 6/19/1998 O.S4 1 10/30/2002 8/20/2002 29,2 No-flow conditions 5/2B/2002 51 4/24/2002 3/2B/2062 2/25/2002 1/2B/2002 12/12/2001 10/3/2000 12/29/1899 28.9 66.6 24.3 42.4 20.5 27.6 97 5/19/1998 4.6 1/29/2003 20(3 Tab 6.4 Consent Order T&P.xts A.SH021753 EID639985 Table 6.4 ' Summary of Analytical Results: C-8 in Surface Water Dry Run Landfill Lubeck,WV ': Sampio DRL6ACHATE POND UNDERDRAIN Date 10/30C002 e-iLuflfl) , 704 5^8/2002 160 412AIVM2 237 SKSRSWi 334 WSIWXt 2S6 1/2B/2002 39$ 12/120001 109 10/3ffi000 12/29/1&89 27,4 34 5/18/1898 S6 7/22/1897 62 10/30/2002 5/28/0)02 4/24/2002 ' 3/26/2002 2/26/2002 1/28/2002 12/12/200'( 38.8 67.4 33.4 66.7 37.1 29.3 35.4 .. 1/29/2003 3 of 3 Tab 6.4 Consent Order T&Fjds ASH021754 EIH639986 Table 6.5 Summary of On-slts and Off-site 'Exposure Pathways Evaluation Dry Run Landfill Lubeck,W On-SIte Off-Site C-8 impacted Madia SWMUs/LandfiHed Materials Soil Lsacrrate {captured& treataci) Surface Water Groundwater C-8 Impacted Media Human Health Exposure Pathways Pathway Assessment (Complete or Incomplete) C Coniparlsoft to Screening Criterta* -- c w I c 87ug/K'!50ugft I -- Exposure Pathways for Human and Ecological Receptors Pathway Assessment [Complete (C) or IncompiBta ^] Comparison to Screening' Criteria* Orinking Water (wetis, springs and/or cisterns) - Dry Run C Mon-drinking water {wets, springs andtoroiateras) - Diy Run C Unused water sources - Dry Run I 0.422 ugfi 150 Ug/l 0.54ug/l150ug/l Ecological Expo Pathway Assessment {Complete or Incomptete) C Comp Criter C I C I * Highest value Encategory ia compared to the screening criteria. Screening criteria was established by CATT of 240 ma/kg for (surface- water), 150 og/1 for drinking water. For complete exposure pathways, a8 water samples are compared to the drinking w ' consec^ive.MoGorTartsonJs.matief(rtacomDeteeTOowre&^^ . 2/4/2003 loft Tab eeeeeaaia 9Si.TKOttY ^ ASH021757 EID63&&8& ASB021758 EID639990 ASB02175& EID639991 ^uss ^1)5 ASB021760 BIt639992 ': LEGEND ^w^"a-- O-'"1*TM = lOJ MOWTOR8NQ WBLL PROOUCT10N WELL CONCENTRATION OF IN GROUNDWATER C--S <ugA) " ^Ss- CotpOltltB Rirod AMjAHIjiMiM* o ASB021763 EID639995 ASH021764 EID639996 ASH021765 EID639997 ASHQ21766 EIDe3&&&8 ASH021767 EI&639999 ASS021768 EID640000 TOOO&aaiH G9LTZOBSV 0 to LU o II 3 i a8 "& JT |a B.6 0< 5 ^ -8 ASH021770 EID640002 ^WSK: ^W. f? ^W>^&^y^^ Remote User Remote User flJob 184 07/16/04 10^30 AIVI ASH021771 EID640003 ASH021772 EI0640004 LEGEND $.'*""" - ^IMF--W ^ ^w-jtt.w^ A A "' - MONITORING WEUPRODUCTION weUOUTFAU- SAMPUNG POINT CROSS SECTION UNE ST. Coi> 8 ASH021774 BID640006 S g sC_O t/> Holoctna Aji| Ohio Rmir 1 OvtritOnk Dttoaital H^-<\S, !l|i gin 4- SCQ -2. OSH *<) MOIlYArB M liJi Tl J m ASH021775 EID640007 ASH021776 EID640008 eooofrsaia LLLtZOUSV [ TopBofl"" 01. | Stwt - SM.SW* | Sond and Gravel F-111 ILU11 silt -- MI. sw.epi.ow.oM LEGEND: ^^ F"^ cya PBBt - PT Bwireck any - CL Sicttc Wrttr tavri. Dec. 193) : Awoximatt Solo(te COTtoet . Statfc Wtttur Level, InfeTed S Gnmn*Kitf BB Direetbn ^- Ki ASH021779 BID 640011 LEGEND; p%>^ |,%^;^| HOLOCENE OVERBANK DEPOSITS -SILT AND CLAY PLEISTOCENE GLACIAL OUTWASH DEPOSITS COARSE SAND AND GRAVEL HORIZONTAL SCALfit 1""'40' VERTIOAL SCALE! t"20" ^ Corpojmf RwiMdUiHen Group JJB<_. tehouii IHrw <mt USS Wmtirut Bnrtey Mtt (teat BidcDng 27 Wilmlltlton, BJoinr* 190B3 SECTION G-G' DuPont Washington Works Washington. Wtet. Virglnto ASH021780 EID640012 ASH021781 EID640013 ASH021782 EID640014 ASH021783 E1D640015 ASB021-784 BID 640016 ASH021785 EID640017 ASH021786 EID640018 ASH021787 EID640019 ASH021788 E1D640020 Teoofrsaia 68j,TZOB8V ASH021790 EID640022 ASH021791 13ID640023 ASH0217&2 BID640024 ASH021793 EID640025 AS80217&4 EID640026 ASa0217&5 BID640027 ^^--j^y fi S oB s a a s 1> t- r*~ f* a'S(/. UJ 8 !* z" Ld M 4 0 0 h. "CO CO 5 g &{ 5 i s ^ COi 1--------? CTSH) NOtlVA3T3 ASH021797 EID640029 ASH0217&8 EID640030 ASH021799 EID640031 ASH021800 EID640032 ASH021801 BID640033 ASH021802 10640034 A8H021803 BID 640035 ASH021804 EID640036 ASH021805 EID640037 8 @ ASH021806 BID 640038 IHSENO; WjfS ESSi SILTY CStAY SANDSTirONE AMD 'StLTSTONE C3 SHAt 1 WEULS CKEEN :INTeRV<<U- -x- <;===' KOffi CROUHOWATBR OROUNOWATBR AQUTglFS? ZONE eLVA7ION (Oct. FLOW DIRECTION 2002) SECTION B-B' S C A 1. E 160 0 tW VEBHCU. OHSCSMnOM OFA^X CoipW BiA Mm ASH021808 EID640040 ASH021810 EID640042 ASH021811 EID640043