Document LpqONJdKYKV7VryKYmOVY7e3d

AR226-2521 C-8 DATA SUMMARY REPORT CONSENT ORDER GWR-2001-019 DUPONT WASHINGTON WORKS FACILITY AND LOCAL, LETART AND DRY RUN LANDFILLS ') Dale: February 2003 Project No.: 7423 18983753.00036 CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Diamond Barley Mill Plaza, Building 27 Wilmington, Delaware 19805 A SH 021621 BID639853 0 -8 Data Summary Report Table of Contents TABLE OF CONTENTS Executive Summary.... ,......................................... 1.0 Introduction ............................... 1.1 Document Organization....................... 2.0 C-8 Analyses and Analytical Reporting,,...,,,,, 2.1 Independent Quality Assurance Review 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 o f C-8 in Groundwater and Surface Water.....................10 3.3.2 Ohio River Water Quality,.....,...................................... 12 3.3.3 Public Water Supply Sampling.............................................. .. 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 Works Facility...................................................... 14 3.4.3 Washington Works Groundwater Model Refinement....... ......... 15 3.4.4 Surface-water Field Reconnaissance at the Washington Works Facility........ ........................... 15 3.4.5 C-8 Monitoring in Groundwater and Surface Water at the Washington Works Facility...................................... 15 3.4.6 Washington Works Facility Site Conceptual Model Refinement....,..,....,....,........,.,.........,........ 16 3.5 Revised Site Conceptual Model......................... 16 3.5.1 Current Environmental Setting...........................................................16 3.5.2 Current Human Health and Ecological Exposure Pathways............. 21 3.6 Washington Works Facility Summary............. 24 4.0 Local Landfill................................... . ****>**! ******>+***#*********!.*****26 4.1 Introduction,........................................... 26 4.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling.,...,.... ........................... .................................................................. 26 4.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data........................... 27 W W K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington. DE i ASH021622 110639854 C '8 Dala Summary Report Table of Contents 4.3.1 Monitoring o f C-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 Landfill..................................................... .............-- ..................... 28 4.4.2 Surface-water Field Reconnaissance at the Washington Works Facility........................................................... 29 4.4.3 Installation o fNew Wells at Local Landfill............................. 29 4.4.4 Local Landfill Site Conceptual Model Refinement....... 29 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.................................................. ..................... --*..........................- 3 7 5.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data................................................................ 38 5.3.! Monitoring o f 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 Landfill.............................................. 40 5.4.2 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 Monitoring Data............................ .....51 6.3.1 Monitoring o f C-8 in Groundwater 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 Run Landfill................................................................ ...................... . 53 6.4.2 Surface-water Field Reconnaissance at the Dry Run Landfill...........54 6.4.3 Installation ofNew Wells at Dry Run Landfill ..............................54 6.4.4 Dry Run Site Conceptual Model Refinement.................................... 54 WW K-C-0 Dala Summary - text (Inal Feb. 5 ,0 3 Wilmington, PE li ASB021623 EID6398S5 C-8 Data Summary Report Table of Contents 6.5 Revised She Conceptual Model......................................................... 6.5.1 Current Environmental Setting..........................................6.5.2 Current Human Health and Ecological Exposure Pathways 6.6 Dry Run Landfill Summary.................. ............................................. 7.0 References............................... -- ............................................................. Table 3.0 Table 3.1 Table3,2 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 Summary of C-8 Analytical Results in Groundwater and Surface Water Ohio One-Mile Radius Residential Sampling Summary of Off-Site Sampling Program (C-8 Sampling) - Ohio Two-Mile Radius Residential Sampling Summary o f C-8 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 o f Analytical Results: C-8 in Groundwater - DuPont Washington Works Facility Summary o f Analytical Results: C*8 in Surface Water - DuPont Washington Works Facility Ohio River Water Sampling C-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 Washington Works Synoptic Groundwater Elevations, February 2002, and Well Screen Locations - DuPont Washington Works Facility W W K -08 Data Summary - text final Feb. 5 .0 3 Wilmington, D ASH021624 1IC 639856 C-8 Dato 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 o f Analytical Results: C-8 in Groundwater - Local Landfill Summary o f Analytical Results: C-8 in Surface Water - Local Landfill Summary o f On-Site and Off-Site Exposure Pathways Evaluation - Local Landfill Summary of Off-Site Sampling Program (C-8 Sampling) - Letart Landfill Summary of G-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 Summary of Analytical Results: C-8 in Surface Water - Letart Landfill Summary o f On-Site and Off-Site Exposure Pathways Evaluation - Letart Landfill ' Summary of Off-Site Sampling Program (C-8 Sampling) Dry Run Landfill Summary o f C-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 o f Analytical Results: C-8 in Groundwater - Dry Run Landfill Summary o f Analytical Results: C-8 in Surface Water and Leachate - Dry Run Landfill Summary o f On-Site and Off-Site Exposure Pathways Evaluation - Dry Run Landfill Figure 1.0 Figure 3.0 Figure 3.1 Figure 3 2 FIGURES 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 W W K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington. 0 1 iv SB021625 E ID 639857 C-8 Date Summary TableReport_________________________________________________________________ of Contents Figure 3.3 Monitoring Weil and Surface Water Sample Location Map - DuPont Washington Works Facility Washington, WV Figure 3.4 Figure 3.5 C-8 in Groundwater - 4Q02- DuPont Washington Works Facility, Washington, WV Ohio River Water Sampling Locations - Upstream - DuPont Washington Works Facility, Washington, WV Figure 3.6 Ohio River Water Sampling Locations - Downstream - DuPont Washington Works Facility, Washington, WV Figure 3.7 C-8 Concentrations (ug/1) in the Ohio River and Public Water Supplies DuPont Washington Works Facility, Ohio - West Virginia Figure 3.8 Idealized Ohio River Valley Cross-Section and Block Diagram - DuPont Washington Works Facility, Washington, WV Figure 3.9 Generalized Geologic Cross-Section at River Mile 190 - DuPont Washington Works Facility, Washington, WV 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 Cross-Section Location Map - DuPont Washington Works Main Plant, Washington, WV Cross-Section A-A' - 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 F-F' - 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 M ap-L ocal Landfill, Washington, WV . Figure 4.1 Figure 4.2 Local Landfill Monitoring Well and Surface Water Sample Location Map - Local Landfill, Washington, WV Cross-Section Location Map - Local Landfill, Washington, WV Figure 4.3 Geological Cross-Section A-A' - Local Landfill, Washington, WV Figure 4,4 Geological Cross-Section B-B' - Local Landfill, Washington, WV WWK-C-B Data Summary - text final Feb. 5 ,0 3 Wilmington, DE EID639858 C -8 Data Summary RfepOfl 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 Geological 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 Blinker'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 Gross-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 Groundwater Contour Map - 4QD2 - Letart Landfill, Letart, WV F-Zone Groundwater Contour Map - 4Q02 - Letart Landfill, Letart, WV Site Location Map - Dry Run Landfill, Luheck, WV C-8 in Groundwater - Dry Run Landfill, Luheck, 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, Luheck, WV Cross-Section B-B' - Dry Run Landfill, Luheck, 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 WW K-C-8 Date Summary te e Anal Feb. 5 ,0 3 Wilmington, DE vl ASH021627 EID639859 C -8 Dala Summary Report Table of Contents APPENDICES Appendix A Boring Logs and Well Construction Diagrams - Washington Works Facility ' Appendix B Boring Logs and Well Construction Diagrams - Local Landfill Appendix C Boring Logs and Well Construction Diagrams - Lctart Landfill Appendix D Boring Logs and Well Construction Diagrams - Dry Run Landfill W W K-C-8 Data Summary --text final Feb. 5 ,0 3 Warninglon, DE V I ASH021628 EID639860 0 8 Data Summary Report Executive Summary EXECUTIVE SUMMARY A multi-media consent order (Order No. GWR-2001-019; Consent Order) wasentered^ 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 IS, 2001. The Consent Order identified a series o f 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 o f releases of ammonium periluorooctanoate (0 8 ) , CAS Number 3825-26-1, from DuPont operations at the Washington Works facility (facility, also referred to as the "main plant") and the associated landfills (Local, Letart, and Dry Run). ' The Consent Order established the C-8 Groundwater Investigation Steering Team (GIST) to oversee investigations and activities o f the Consent Order including Task A: Groundwater Use and Well Survey/Groundwater Monitoring, Task B: Assessment of Existing Groundwater and Surface Water Monitoring Data, and Task C: Plume _ Identification/Groundwater Assessment at each site. The Consent Order also established the C*8 Assessment o f Toxicity Team (CATT), which consisted o f 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 o f 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 o f the exposure pathways evaluation. This evaluation assessed whether human and ecological receptors were exposed to C-8 impacted media (e.g., soils, surface water, groundwater) both on-site and off-site on the basis o f data collected under the Consent Order. Pathways were classified as complete or incomplete. To be conservative, the highest C-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, that the CATTestablished Aquatic Life Advisory Concentration for C-8 (C-8 ALAC) o f 1,360 ug/1 is a more appropriate benchmark for evaluation provided that waters are not ingested such as surface water, groundwater, process water, and leachate. In this table, highlighted boxes 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 die C-8 SL. Most importantly, this table shows that all drinking-water sources are substantially below C-8 SL. WWK-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington, PE ASH02629 1 1 0 6 3 OS61 :\ I C-B P ala Summary Report Executive Summary C-B Impacted Media Exposure Pathway Assessment [Complete (C) or incomplete (1)) Human Receptors Ecological Receptors SWMUs/Lsnrililled Materials 0) Soil ma Surface Water Groundwater Drinking water (from groundwater) Process water (tarn groundwater) Drinking Water (wells, springs and/or cisterns)-WV Non-drinking water (wells, springs and/or cisterns) - WV Unused water sources - WW Drinking Water (wells, springs ! 1 and/or cisterns)-OH Non-drinking water (wells, springs and/or cisterns) - OH Unused water sources OH Ohio River water PWS (WV and OH) l 1 1 1 C [1.9 (L) ug/l] C (51.2 ug/l) C (2.8 ug/l) C (5.07 ug/l) i C (8.59 ug/l) C (23.6 ug/l) 1 C (1.09 ug/l) C (4.29 ug/l) 1 1i 1 NA NA . 0(2.8 ug/l) C (5,07 ug/l) 1 C (8.59 ug/l) .... . ^ C G & $ u g n) ' "T : (1.09 ug/i) C (4.29 ug/l) ! f SWMUs/LandBlled Materials Soil Leachate Surface Water Groundwater Drinking Water (wells, springs and/or cisterns) - WV Non-drinking water (wells, springs and/or cisterns) - WV Unused water sources Local I 1 C (120 ug/l) C (115 ug/l) 1 C (2.8 ug/l) C (5.07 ug/l) 1 1 1 C (120 ug/l) C (115 ug/l) l 0(2.8 ug/l) 0(5.07 ug/l) 1 ... SWMUs/Landfilled Materials Soil . Leachato 1 Surface Water Groundwater Drinking Water wells - Letart Non-drinking water wells- Letart i Ohio River water Unused water sources - Letart 1 1 C (2050 ug/l) G (371 ug/l) 1 G (0.139 ug/l) CINQ (<0.05)] C (0.12B Ui}/|) 1 1 1 C (2050 ug/l) G (371 ug/l) 1 C (0.139 ug/l) C[NQ 0.05)] C (0.128 ug/l) i SWMUs/Landfilled Materials So _ _ _ _ _ _ a Leachate (captured and treated) Surface Water Groundwater. Drinking Water (wells, springs si ?, and/or cisterns) - Dry Run V Non-drinking water (wells, springs 1 and/or cisterns) - Dry Run 1 Unused water sc u te * Dry Run C (Unknown) C (Unknown) 1 C (87 ug/l) ,1 C (0.422 ug/l) C (0,54 ug/l) 1 C (Unknown) C (Unknown) 1 c (87 ug/l) 1 C (0.422 ug/l) C(0.54 ug/l) 1 (L) = biased low NA= not applicable Highlighted cells indicate exceedence of CATT-establlshed 0 8 SL (150 ug/l) W W K-CB Data Sum m ary- text final Feb- 5 ,0 3 Wilmington, DE |jj ' ASH02J.630 E IB 6 3 9 8 6 2 C-8 Dala Summary Report executive Summary For the Washington Worksfacility,, 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: O Solid Waste Management t Jnits (SWMUs) on-site are believed to be the primary source of C-8 migration to groundwater. Air deposition o f C-8 on the ground surface and migration to groundwater also may have occurred, Q No offsite migration of groundwater is occurring. 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. Q Air emissions of C-8 from the facility also are believed to be the source o f C-8 cdricenfratidhsTefecfedTh West Virginia adjacent'to the'faalify andTbca! Landfill. Q Air emissions o f 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 $L 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: C-8 is believed to migrate via water transport from C-8 containing landfilled materials to groundwater at the Local Landfill. . Groundwater 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 from the facility via air emissions, 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: C-8 is believed to migrate via water transport from C-8 containing landfilled materials to groundwater at the Letart Landfill. Groundwater flow at Letart Landfill is toward the Ohio River and is away from off-site residential areas. W W K-O-8 Data Summary - text final Feb. 5, 03 Wilmington, DE ASH21631 1ID 639S 63 0 8 Date Summary Report Executive Summary The annual C-8 loading from groundwater to the Ohio River indicates a very low C-8 concentration in the river from the landfill, which is supported by the very low C-8 concentrations measured in the Ohio River, Air emission of C-8 is not a viable migration pathway because there are no air emissions at Letart Landfill. Q Contact with surface water (Cap Runolf location) and leachate at the toe of the Letart Landfill and in the wet-weather stream surface water that discharges to 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 o f the landfill, the very steep terrain, and the wet-weather nature o f the stream. In addition, fencing limits access to the area. Further, the use o f 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. 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 o f C-8 Impacted groundwater has occurred. Dry Run Landfill is located within eight miles o f the facility. Transport of C-8 via air emissions from the facility potentially could be the source of the very low concentrations o f C-8 detected within the one-mile radius sampling area. WWK-C-8 Date S um m aty- text fir! Feb. 5 .0 3 WiWth^ton. BE SB021632 EID639864 C-B Date Summary Report Introduction 1.0 INTRODUCTION Since the early 1950s, ammonium perfluorooctanoate (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 containing C-8 from these processes have been released to the air, discharged to the Ohio River; disposed o f at the Washington Works facility and/or at the DuPont Local, Letart, and Dry Run landfills; and otherwise shipped off-site for destruction or disposal (see Figure 1.0). C-8 has been detected in varying concentrations in and around the Washington Wotks facility and the associated landfills (Local, Letart, and Dry Run), in private drinking wells 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 o f 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 o f 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 Steering Team (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 o f the Consent Order. Pursuant to Attachment A o f 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 the three landfills by sampling water from wells, cisterns, and springs. Included with these sampling activities was the sampling o f PWS located one mile upstream and ten miles downstream of the facility. The area o f 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 w an included in the One-mile Radius Survey and C-8 Sampling Report and the Ohio River Public Water Supply Sampling (DuPont, 2002a). Task A activities are re-summarized in this report. Task B; Assessment o f 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 die GIST for evaluation (DuPont, 2002b). The second part o f Task B, monitoring C-8 in surface water and groundwater 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, 2002d). WW K-OO Data Summary - text final Feb. 5 .0 3 Wilmington. DE ASH02X633 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 Tdentification/Groundwater Assessment at each she began following the completion o f Tasks A and B. This activity included delineating the vertical and horizontal extent of C-8 impacted groundwater and specifically included an assessment of C-8 impacted groundwater at the Letart Landfill and its impact on the Ohio River and PWS along the river as required by the Consent Order. The C-8 Plume Identification Groundwater Assessment Work Plan was submitted to the GIST in May 2002 (DuPont, 20O2e). For the Washington Works facility, Task C included groundwater modeling using GIST-approved groundwater modeling tools. Groundwater modeling was used to evaluate possible C-8 migration pathways in groundwater from the facility. A separate groundwater modeling report was issued to file GIST in January 2003 (DuPont, 2003a). This report documents Task C activities and re-summarizes briefly the groundwater modeling results. While conducting the activities identified in Tasks A, B, and C, which were designed to assess the presence and extent o f C-8 in drinking water, surface water, and groundwater, an evaluation o f transport mechanisms for C-8 migration also was conducted. This evaluation was conducted to gain a bettor understanding o f how C-8 migrates m the environment and to better understand the results generated during the implementation of Tasks A, B, and C. . Two main possible transport 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 deposited on surfaces o f structures (roofs, etc.) and then have been dissolved and transported by precipitation into cisterns. C-8 in air emissions also may have been deposited on 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 disposed o f on-site (i.e,, facility and landfills) and C-8 had been detected in surface water and groundwater from various sources at and near the Washington Works fatality and the three landfills. Sampling performed under Task A o f the Consent Order resulted in detections o f 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 o f Toxicity Team (CATT). The ' CATT consisted o f scientists from academia, government, non-profit organizations, and industry. The CATT was assembled to assess the toxicity and risk to human health and WW K-C-a D ate Summary - text final Feb. 5 .0 3 Wilmington, DE ASH021634 3ED639866 0 8 Date 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 screening criteria for water (C-8 SL) of 150 ug/I (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 o f 150 ug/1, regardless o f water 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) o f 1,360 ug/1 in 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 ofthis document provides information on C-8 reporting and data validation. The remainder o f this report discusses specific activities conducted and results obtained at the Facility and the Local, Letart and Dry Run Landfills. Section 3 presents the Washington Works 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 foe new results, is then discussed. A human health and ecological exposure assessment follows. Finally, observations for each site are summarized. Section 7 o f foe report provides a reference list, including Consent Order related documents previously submitted to the GIST, W W K -08 Date Summary * text final Feb. 5 ,0 3 Wilmington, DE ASH021635 E D 639867 C-8 Data. Summary Report C-8 Analyses and Analytical Reporting 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 groundwater investigation at The facility and associated landfills are technically sound, usable, and properly documented. Specifically, Sections 5,6, and 10 o f the QAPP present sampling protocols, sample and document custody procedures, and internal quality control checks that were followed during the 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/Tandem Mass Spectrometry (LC/MS/MS). DuPont adopted this method (LC/MS/MS) for analyzing C-8 in water in November 2001. Currently, Exygen performs all C-8 water sample analyses for DuPont using the laboratory Standard Operating Procedure (SOP) it developed. . Exygen reports C-8 results for die laboratory replicate o f each field sample. These results are evaluated for precision by comparing the field sample result to foe corresponding laboratory replicate result: Q If both results are less than the practical quantitation limit (PQL), foe replicate sample for that analyte is considered to have passed foe precision criteria. Q If one or both results are between one and five times the PQL, foe replicate is considered to have met the precision criteria if the two results differ by less than the PQL. If one result is less than foe PQL and foe other is not and if foe two results differed by a value less than the PQL, foe replicate is said to have met the acceptance criteria. Finally, if both results are at least five times foe PQL, the replicate is considered to have met foe criteria if foe relative percent difference (RPD) between the two results is less than or equal to 20%. The RPD is foe absolute value of the difference o f two measurements divided by their average. When foe precision criteria outlined above are met, Exygen Teports foe average o f foe field sample and foe laboratory replicate results are reported. If criteria for precision are exceeded, Exygen reports foe higher o f the sample and laboratory replicate results. Finally, when one result (from the sample/laboratory replicate pair) is above foe PQL and one below, foe result that is above the PQL is reported. C-8 results are recorded in foe Corporate Environmental Database (CED) and are reported as FC-143 for consistency with historical results. W W K-C-8 Date Summary - text final Feb. 5 .0 3 Wilmington. OE ASH021636 1 EID639868 C -$ Data Summary Report .$ Analyses and Analytical Reporting An aliquot o f each field sample also is 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. 1ne 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 o f 5%, or one each per analytical batch (whichever is greater) for groundwater and surface-water samples collected withm the facility and landfill boundaries. Specifically, analysis of well, outfall, and sfoam samples collects at the facility, Local Landfill, Letart Landfill, and Dry Run Landfill were subsequently performed with the reduced QC sample frequency. This reduction ro QC sample frequency was made because a substantial database exists for these samples, including at least three rounds of sample analysis at Exygen. There was no reducfaon m QC sample frequency for samples collected 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 the QAPP. Results o f the in-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 reported by Exygen have been judged usable for the purposes of the project. Exygen reported that seven o f 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 specified hold time. The laboratory also has reported that non-project, field spiked samples at 100 and 1,000 ug/1, have exhibited stability for periods as long as one year (Exygen, 2002). The data packages were examined in-house, using the review protocol included in foe QAPP, and foe results were determined to be usable for project purposes. All data reported by Exygen have been judged usable for foe purposes o f the project. 2.1 Independent Quality Assurance Review A subset of foe data packages generated by Exygen were submitted to Environmental Standards, foe (ESI) in Valley Forge, Pennsylvania, for an independent (ne., third-party) . quality assurance review. Thirty-eight data packages, containing results for 326 samples, including field blanks and duplicates, were submitted for validation. The samples submitted for review represent samples collected from foe West Virginia one- and twomile radius, Ohio one-and two-mile radius, Ohio River sampling, and PWS. The samples submitted for review represent 23.7% o f foe samples, collected between December 2001 and November 2002, from foe 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/samp]es submitted for foe independent quality assurance review were selected at random; however, off-site residential and PWS . samples were preferentially selected because these samples were collected from drinkmg- W W K -08 Date Summaiy - text final Fb. 5 03 Wilmington. DE 1IP639869 C -8 Data Summary Report C-8 Analyses and Analytical Reporting water sources. In addition, samples o f 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 [United States Environmental Protection Agency (USEPA), 1994], Data were examined by ESI to determine the usability o f the analytical results and compliance relative to the QAPP, QAJPP Addendum, and the laboratory SOP. Results of the quality assurance review indicated that the quality of the data is acceptable and qualification o f the data was not warranted, with the exception that positive results for two samples reviewed were qualified 3, as estimated, due to precision criteria between the sample and lab replicate not being met. It should be noted that the laboratory, mid DuPont, in this case and any similar cases for data not submitted for independent review, reported the higher of the two results. WWK-C-B Data Summary - text final Feb. 5 .0 3 Wilmington, DE A S H 0 2 6 3 8 EXD639870 C-B Data 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 wiles southwest of Parkersburg, West Virginia (see Figure 3.0). Consent Order required tasks to be conducted at or immediately adjacent to the facility 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 Local LandfilL D Task B: Assessment o f Existing Groundwater and Surface Water Monitoring ' D ata--develop and implement a monitoring plan that evaluates the presence and extent o f C-8 in drinking water, groundwater, and surface water in and around the facility and perform an assessment of C-8 impact to the Ohio River and to PWS wittun one mile upstream and 10 miles downstream (and possibly two and three miles upstream and 20 and 30 miles downstream) of the facility. Task C: Plume Identification/Groundwater Assessment--determine the vertical and horizontal extent of C-8 impacted groundwater exceeding l ugfl 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 o f the Consent Order are presented along with the new data acquired while conducting these activities. In Section 3.5, the revised site conceptual model updates 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 site. 1- 3.2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling 3.2.1 One-Mile Radius Sampling The Local Landfill is located immediately south o f the facility. Because of the proximity o f the Local Landfill to the facility, groundwater wells located within the combined onemile radius (ofboth sites) in West Virginia were sampled (see Figure 3.1), The groundwater well and water-use survey and sampling within the one-mile radius o f 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). W W K-C-fl D ata Summary - text final Feb. S. M Wilmington, DE A SH 2163& E D 639871 C-8 Data Summary Report Washington Works Facility Table 3.0 summarizes the off-site survey and sampling program for the one-mile radius. A total o f269 homes were surveyed, and a total o f 44 water sources were sampled, b.x wells used for drinking water were sampled. No cisterns or springs sampled were use for drinking water. 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, regardless o f water use. Each colored circle represents a sampling location and the color and size of the circle indicate the magnitude o f the C-8 concentration measured. For example, small black circles represent samples having 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/1 are 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 driving-water samples had C-8 concentrations above the 1 ug/1 threshold level described by fire Consent Order, die GIST ordered the expansion o f the radius to two miles and resampling the drinking-water samples within the one-mite radius. The highest C-8 concentration m a non-drinking source was 5.07 ug/1. The highest C-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 o f C-8 as a migration pathway was possible if 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-mile radius o f the facility and the Local Landfill were completed on June 3,2002. DuPont submitted the results o f file two-mile radius survey to the GIST in August 2002 (DuPont, 20Q2h). Table 3,2 summarizes the off-site survey and sampling program for the two-mile radius. Within the two-mile radius a total o f 109 homes were surveyed, and 65 water sources were sampled. Seventeen wells and one spring used 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 the C-8 results for the two-mile radius. All samples are posted regardless ofwater use. O f 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 spring sample was 1.8 ug/1. All drinking-water samples from wells had C-8 concentrations less than 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). I WWK-C-B Data Summary - text final Feb. 5 ,0 3 Wilmington, DE A SH O 21640 IID 639872 C-8 Date Summary Report Washington Works Facility 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, the 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 forth 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 sampling also 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 foe facility boundary into Ohio. The groundwater well and water-use survey and C-8 sampling within foe one-mile radius in Ohio were completed on June 7,2002. DuPont submitted the results of foe one-mile radius survey to foe OEPA and the GIST in August; 2002 (DuPont, 2002i). ' Table 3.4 summarizes foe one-mile radius survey and sampling in Ohio, The total number of homes surveyed was 150, and the total number o f water sources sampled was 68. O f foe 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 foe samples collected, including foe measured C-8 concentration. The C-8 concentration measured for foe drinking-water wells ranged from non-detectable [<0.01 ug/1 (ND)) to 8.59. The C-8 concentration for a drinking-water spring was 1.29 ug/1. The highest C-8 concentration measured in non-drinking-water sources and unused sources was 23.6 mid 16.9 ug/1, respectively. Figure 3.2 is a map showing the location o f samples, regardless o f water use, collected within foe .Ohio one-mile radius. This figure uses foe same symbols a$ were used in Figure 3.1. Locations o f samples having -8 concentrations greater than 10.0 ug/1 appeared to be clustered to foe 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 possible migration pathway from foe facility, providing foe cisterns were filled by precipitation. Even though foe highest C-8 concentration measured for a drinking-water sample within the one-mile radius was an order of magnitude lower that foe CATT established C-8 SL of 150 ug/1, nine non-drinking-water and unused water source samples had C-8 concentrations above 10.0 ug/1. Based on these results, OEPA requested an expansion of foe survey area to a two-mile radius. 3.2.4 Ohio Two Mile Sampling The groundwater well and water-use survey and C-8 sampling within the two-mile radius of foe facility were completed on September 30,2002. DuPont submitted foe results of WWK-C-8 Dato Summary - text final Feb. 5 .0 3 Wilmington, 0 6 A0HO2X64! EID639873 i 'i ' 1 I C-8 Paia Summary Report 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 sampling strategy 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. Inarea``B" all idaitified wells, springs, and cisterns were sampled, regardless o f use (dunking water, non-dnnking water, or unused) because this portion o f the two-mile radius was adjacent to an area within the one-mile radius where die highest C-8 concentrations were measured. In addition, all identified drinking water, non-drinking water, and unused wells, spnngs, 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 it these _________ _ riftn-drinkinn-water and unused sources were not Table 3.6 provides a summary o f the Ohio two-mile survey results, to total, 733 homes were surveyed, and 62 water sources were sampled, including 49 wells used for drinking water. No cisterns or springs sampled were used as drinking-water sources. Figure s .2 also shows the location o f samples, regardless o f water use, collected within.the Ohio two-mile radius. Table 3.7 provides details o f the samples collected, including the measured C-8 concentrations. The C-8 concentrations measured m drinking-water samples ranged from ND to 6.5 ug/1, with only 11 samples having C-8 concentration greater 1 0.ug/1. The highest C-8 concentration measured for the non-dnnkmg-water samples ranged was 6.85 ug/1. The highest C-8 concentration measured m an unused source was 8.68 ug/1. The range o f C-8 concentration m the three cistern samples was from 0.217 to 0.592 ug/1. Overall, the C-8 concentrations are lower to the two-mile radius samples than in foe one-mile radius. ' While foe groundwater w ell arid water-use survey and C-8 sampling w ere being conducted in foe one^.and riyo-mUe radius to Ohio,.gropdwater ^ r ,ng conducted. One o f foe objectives o f foe groundwater modeling effort was to determine foe likelihood that off-site migration o f C-8 impacted groundwater was occurring. The groundwater modeling showed that no potential groundwater migration pathway exists beneath foe Ohio River (DuPont, 2003a). Therefore, air transport of C-8 is foe 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 o f facility monitoring wells were to be sampled following foe development o f a groundwater monitoring plan by DuPont (DuPont, 2002c) and its approval by the GIST (DuPont, 2002d), Frequency o f sampling WW K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington. 0 6 ASH021642 EID639874 C-8 Data Summary Report Washington Works Facility S , towas to be monthly for the first four months following the effective date of the Consent Z S r l J t o , H e , . Monthly sampling of ground , beg," m January 2002^' Quarterly sampling beganinM ay2002 (2Q02). Thu 4Q02 ntomtonug report was submitted to the GIST in December 2002 (DuPont, 2002k). Table 3,8 provides a list of the production and monitoring wells included in the groundwater monitoring program for the facility. Well construction data and groundwater elevation data also are provided in this table. The three new bedrock monitoring wells (AJ06-MW02, N04-MW03, and Y14-MWTO) that were insulted! 3Q02 as part o f the C-8 plume delineation work plan were added toi 8 Tible 3 9 nroaram in 4002. F ip re 3-3 shows the location the wells listed m Table 3,8. Table 3.9 i S S o f L e T c o n c e n t r a t i o n s measured in these production and -- n ^ w e lls through October 2002, including C-8 data acquired prior to the issumgof theConsent ( X The most recent data are listed first for each well. F ip re 3.4 shows the October 2002 C-8 concentrations in groundwater. Table 3.9 shows that, in general, monitoring and production WStem half of the facility have shown a C-8 concentration range from 0,071 to 2.82 ug/l (A ll 1-MW01, AM07-PW01, A008-PW01, and AX13-PW01)_ nonitonngand production wells in the western half of the site generaly 1have^" ^ c o n c e n t r a ti o n L e e o f O 117 to51.2ug/l (V05-PW01,L04-PW01,N13-MW01. Y14-MW01, S & W 0 1 , West Well Field 1, E13-MW01, and-DOS-MWOl). Monitoring wells located Hiarent the Ohio River near the former Anaerobic Digestion Ponds have higher C 8 SSS t o leas than 100 to 84,100 ug/l (P08-MW01, P04-MW02 Q - MW02, and R04-MW02). However, evaluation o f bonng lo p for these well sbows that to ee o f these wells are screened in aperched water-table located m the clays and silts that stratigraphically overly the sands and gravels of the primary site water-table aquifer (site aquifer). Q04-MWD2 is the only well included m the groundwater monitoring progr^n located in the former Anaerobic Digestion Ponds area that - e n r o l m the she aquifer. Recent C-8 concentrations measured for this well have been highly varab e, ranging from 32.2 to 7,720 ug/l. (Further discussion o f the wells screened m the perched water-table are presented in Section 3,5.1 ) Available data for the bedrock aquifer are very limited (only three but mnges from non-quantifiable [<0.05 ug/l (NQ)] in the central southern boundary (Y14-MW02) to 0.133 ug/l along in the eastern portion (AJ06-MW02) of the site to 21.2 ug/l in the near the former Anaerobic Digestion Ponds (N04-MWQ3). The next groundwater sampling event for the facility is scheduled for the first quarter 2003. Surface-wafer Monitoring The Consent Order also identified six outfalls1 at the facility ^ areregulated by West Virania/National Pollutant Discharge Elimination System (WV/NPDES) Permit No. WV0001279 and where monthly sampling o f C-8 was required. F ip re 3.3 shows the locations o f the six outfalls. Monthly sampling o f outfalls began in December 2001. The ' In this port, all surface-water samples identified as outlets, inlets, 01 outfalls will be refeired to collectively as outfalls. WW K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington. D 11 s li ASH021643 EXD639S75 C -8 Data Summary Report Washinoton Works Facility ___________ ____ ________ ---- --------- ------------------------------------------ TM November 2002 Surface Water Monitoring Report was submitted to the GIST >n January 2003 (DuPont, 2003b). Table 3.10 summarizes the C-8 concen^hons m ^ u re d tn the outfalls, including C-8 data acquired prior to the issuing of the Consent Order. The most re&cent data are listed nfirst flor eachn outufalmL he six outfalls sampled discharge process water and stormwater runoff to 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 o f C-8, ranging from NQ to 8.56, f^ e c tiv e l* 0 0 * 9 01 and 105 have discharged higher C-8 concentrations, ranging from 2.15 to 54.6 ug/1. Outfall aH w shnwn the hidiest concentrations o f C-8 and discharges the largest volume of e f f l u compared to thfother outfalls at the facility. C-8 concentrations for OitfaH 005 following the installation of a carbon filtration treatment system m the flouropolymers process. , Outfall sampling for December 2002 has been completed, mid the monitoring port^will be issued to the GIST in February 2003. Outfall sampling ^ Ja n u a ry 2003 haSbcen completed, but the C-8 results have not yet been validated. The next monthly outfall ^mpling event 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, hi addition, the evaluation river-water quality was identified as a data gap inthe Compilation o f Historical C-8 report (DuPont, 2002b) m d was included* a recommended activity in the C-8 Plume Identification Work Plan (DuPont, 2002e). The 3 S S S ? W a S p l i n g Proposal for the facility and the Letart Landfill (DuPont, 20021) was developed and submitted to the GIST in January 2002. Near the facility, Ohio River water was sampled to measure concentrations o f C-8 m the Ohio River. The sampling investigation was designed to meet three mam objectives: Q Characterize background C-8 concentrations in river-water upstream o f the facility. Q Assess C-8 concentrations in river water along the facility reach. Q Evaluate C-8 concentrations in river water downstream. Table 3.11 presents a summary of the Ohio River water sampling program, including sampling near 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 show the location o f upstream samples and samples along the facility reach. Figure 3.6 shows the concentration o f downstream samples. C-8 concentrations for each sample are posted. In total, 46 river-water samples were collected, including two duplicate samples. Adjacent to the facility, river-water samples were collected at three locations along two transects across the river. Samples were collected at three depths (dip, imd-column, and WWK-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington. D ASB02644 EID639876 t\ C-B Date Summary Report Washington Works Facility bottom) at each location. Field parameters were monitored during collecUon o f each sample. During the same time period that river water was sampled, effluent from Outfall 005 was sampled to evaluate dispersion downstream of the outfall. Ofthe seven samples collected upstream o f the facility, six wereND, andonewasNQ. Of the 27 samples collected along the facility reach, all were ND except for two that were NO. The range of C-8 concentration for the 12 downstream samples was 0.0949 1 09 ug/1 The two highest -8 concentrations were measured in a dtp and mid-column sample collected approximately three miles downstream from the facility. It is likely that the two highest C-8 concentrations measured in the Ohio ^v erw ater area direct result of increased C-8 concentrations discharged through Outfall 005. Table 3 . 2 shows that the C-8 concentrations measured at Outfall 005 are highly gamble. C-8 data were not collected from Outfall 005 between July 1 and July 10; but, if C-8 concentration was higher on 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 C-8 containing groundwater exists beneath the Ohio River. Therefore, air transport of C-8 to the Ohio liv e r is a likely migration pathway, in addition to the direct discharge o f C-8 containing surface water to the Ohio River through the permitted outfalls. 3.3.3 Public Water Supply Sampling pwsin West Virginia and Ohio at various points upstream o f 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 C-8 concentrations measured the distance upstrefm and downstream was expanded. Sixteen PWS located as far as three miles upstream and 53 miles downstream were ultimately included in the sampling events (see Figure 3.7). Based on the very low C-8 concentrations measured at the various PWS the number of PWS required to be sampled and the frequency o f sampling were reduced by the GIST in May 2002. Table 3.13 presents all the C-8 concentrations measured in the various PWS. For PWS sampled more t o once, the sampling event results are listed in chronological order, . Currently, only t o e PWS, Lubeck (West Virginia), Tappers Plains (Ohio), and Little Hocking (Ohio) are sampled on a quarterly basis (DuPont, 2002m). C-8 concentrations measured at Lubeck ranged from 0.283 to 1.21 ug/1, while C-8 concentrations measured at Tuppers Plains ranged from ND to 0.726 ug/1 (see Table 3.13), Little Hocking had the highest C-8 concentrations of all the PWS sampled. C-8 concentrations in production wells have ranged ftom 0.42 to 8.58 ug/1. C-8 concentrations in drinking water 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 C-8 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/1. 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 production wells at Little Hocking. Groundwater results have been presented WW K-C-8 Pate Summary - text final Feb. 5 ,0 3 Wilmington, DE 13 A SH 021645 EID639877 O B Data Summary Report Washington Works Facility to the OEPA. The method development for analyzing C-8 in soils is still m progress, therefore, none of the soil samples has been analyzed y et As a result, no final conclusions have yet been drawn from this investigation. However, ^ ^ o r t d o c u ^ n . g the sampling investigation and the C-8 results for groundwater and soil will be submitted to the OEPA and the GIST when the analytical results have been finalized. The nextPWS sampling event at Little Hocking, Lbeck and Tuppers Plains is scheduled for the first quarter 2003. 3,4 Task G: Plume Identificatlon/Groundwater Assessment Based on the data gaps identified in the Compilation of Historical C-8 DataReport (DuPont, 2002b), the C-8 Plume Identification/Groundwater Assessment Work Plan was developed and submitted to the GIST (DuPont, 2002e). Included m this work P o w e re specific activities recommended to fill the data gaps. In the following s e c tio n s ^ * 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 installed to further delineate C-8 concentrations in groundwater, to evaluate pundwat flow direction and to determine the vertical groundwater gradients between Ihe bedrock and the overlying sand and gravel. Figure 33 shows the location o f monitoring and production wells, and the locations of the newly installed bedrock wells. Well construction diagrams for the new wells, AJU6MW02, NO4-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 o f 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 Hydrogeologie Testing of New Wells at the Washington Works Facility , Hydrogeologie testing o f the three new bedrock wells was recommended to evaluate aquifer characteristics of the underlying bedrock aquifer in the C-8 Plume Dehneatio work plan. The bedrock monitoring wells were clustered with or locatednear existing wells screened in the primary site water-table aquifer. This allowed for the evaluation of fthlie vertical pgrad*ie!n*t*s bweTMtw*eTMen the pnrimaryv siute watier-tiabwle a4quiTMfer and the underlying bedrock aquifer. Only one round o f water levels was measured for these wells (October 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 m the bedrock and groundwater in the overlying sand and gravel near the former Anaerobic Digestion Ponds area. W W K -& 8 D a Summary - texl final Feb. 5 .0 3 Wilmington, DE 14 ASH021646 EID639878 O S Data Summary Report Washington Works Facility At well cluster Y14-MW01 and Y14-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 higher than in wells located nearby that were measured in February 2002, indicating a likely upward groundwater gradient from the bedrock to the overlying sands and gravel, in this area. 3,4.3 Washington Works Groundwater Model Refinement A groundwater model was developed for the facility as part o f the RFI report for Washington Works (DuPont, 1999). This model was revised during this investigation partially to address the comments generated by the United States Enviromnental Protection Agency and the United States Army Corp of Engineers (USACOE) The Consent Order also required refinement o f the groundwater model for the facility to re evaluate the extent of groundwater captured by the pumping wells at the site and to determine the likelihood that off-site migration o f C-8 impacted groundwater is occurring. To meet these requirements, refinement o f 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 finalization process. The report o f final findings for the revised groundwater model for the facility and the surrounding area was submitted to the GIST in January 2003 (DuPont, 2003a), The revised groundwater ruode] supports DuPont*s previous conclusions that no pff-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 on site and sampling surface 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 beyond those locations that are currently sampled. 3.4.5 C-8 Monitoring in Groundwater and Surface Water at the Washington Works Facility to monitor C-8 in groundwater, in both the unconfined alluvial aquifer and underlying bedrock 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 o f continued monitoring of groundwater and surface water are presented in Section 3.3.1. W W K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington, DE A SH 021647 EID639879 C -8 Data Summary Report Washington Works Facility 3.4,6 Washington Works Facility Site Conceptual Mode! Refinement The final recommended activity for the facility is the integration o f all the new data gathered during completion of Tasks A, B, and C into a revised site conceptual model (SCM). This activity was completed and the revised SCM is presented m the o owi g section. 3.5 Revised Site Conceptual Model The revised SCM ideally represents the current environmental setting (geolop, hydrology, hydrogeology, groundwater flow, and water quality) and current human health and ecological exposure pathways at aid surrounding the site. The following sections present the revised SCM in detail. 3.5.1 Current Environmental Setting . G eology ,. The facility rests on Quaternary alluvial terrace deposits in the Ohio River Valley. Figure 3 8, modified from Siraard (1989), is amodel block diagram showing the complex set of terraces and floodplains that formed in the Ohio Valley because of the glacial advances and retreats o f the pro-, early- and late-Wisconsinan and the resulting successive phases o f alluvial,fills and the incisions into the alluvial fill by the Ohio River. Siraard (1989) identified five facies o f 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 (eotian). A generalized north-south cross-section from the Little Hocking Water Association well field in Ohio, through the Ohio River and across the facility, is presented m Figure 3.9. This cross-section shows the Holocene silt and clay overbank deposits that overlie the Pleistocene sand and gravel outwash deposits and the finer reworked Pleistocene alluvium, thought to underlie the river. The alluvial terrace deposits are m O alam by a fiat, river-scoured bedrodc surface o f the Dunkard Series that rises steeply and foims the valley walls to the North o f Little Hocking Water Association and to the south of the facility. Figure 3.0 shows the relatively flat topography of the alluvial ieirace deposits and the steep topography o f the valley walls to the north and south. The detailed geology underlying the facility is shown on seven geologic cross-sections. Six o f these cross-sections were developed during the Verification Investigation (DuPont, 1992) and revised in early 2002 for the Compilation o f Historical Data Report (DuPont, 2002b) based on additional findings from the RF1. Further refinement o f these six cross sections, based on toe installation o f three bedrock wells, and the generation of a generalized cross-section near the former Anaerobic Digestion Ponds were completed as part of toe C-8 Plume Delineation Work Plan activities. Some o f the test wells and monitoring wells portrayed in toe 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 toe locations of monitoring wells that currently exist at the site. The locations of toe geo ogic WWK-C-8 Dala Summary - taxi final Feb. 5 .0 3 Wilmington, DE 16 ASH02 EID63988 C-B Data Summary Report Washington Works Facility cross-sections A-A' through F- F are shown in Figure 3.10. The location ofG-G' is shown onFigure 3.17. Two east-west cross-sections, A-A' and F -F \ are shown in Figures3.ll 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 expande^ view o the riverbank area near the former Anaerobic D ij^ n m Ponds an e ver Landfill. Note that wells R04-MW02 and P04-MW02 are screened m aperched groundwater zone within the Holocene overbank deposits. The main and oldest Quaternary alluvial terrace at the facility is topographically flat and lies approximately 50 feet above the Ohio River while the remains o younger exist at lower elevations along the riverbank. The Holocene overbank deposits consist of silt, sandy silt, clay, silty clay! and clayey silt. The overbank deposits are approximately 35 feet thick near die riverbank and decrease in thickness away from thenverbank. Under the central portion o f the facility, these overbank deposits range from approximately 5 to 15 feet thick. The overbank deposits are absent m the wertwnporfion ofthe site. The Quaternary alluvium (sand and gravel outwash deposits) ranges fr feet thick (near the river) up to 90 feet thick (under the central portion of the facility). The alluvium consists o f coarsening downward unconsolidated poorly to well-sorted, brown and gray sand, silts, clay, and gravel. The Dunkard Senes bedrock consists primarily o f S and varicolored sandy shale; gray, green and brown sandstone; gray and light gray siltstone; and minor beds of coal, elaystone, black carbonaceous shale, and limestone. Hydrology, Hydrogeology and Groundwater Flow Hydrology Surface water at the facility discharges through drains and storm sewers (outfalls) and drainage swales. Six outfalls (001,002,003,005,007 and 105) collect facility process water m d stormwater runoff and discharge it to the Ohio River. These six outfalls are regulated by WV/NPDES Permit No. WV0001279. The locations of tiiese outfal s are shown in Figure 3.3. Two drainage swales, one located in the facility's southwest corner, and the other located on the extreme eastern end of the facility, convey surface runoff 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, RBLLl and sampled during the VI (DuPont, 1992). This seep likely originates from precipitation that has infiltrated topsoil or fill and flows along the top o f the underlying shallow clay and ultimately discharges along the riverbank (see Figure 3.3). groundwater collection system has been in operation at the Riverbank Landfill once 1991. The RFI verified that the collection system effectively captures water at the seep area (DuPont, 1999). 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 RBLLl (see ' Figure 3.3). Seep water also is captured at this location by way o f an active French-dram collection system. Seepwater is contained in an underground collection vessel that is W W K-C-8 Data Summary - text Anal Feb. 5 ,0 3 Wilmington, DE AB021649 1ID 639881 C -8 Data Summary Report Washington Works Facility pumped out periodically, and the seep water is treated at the wastewater treatment facility on-site. Hydrogeology Regional groundwater,supplies are obtained from the Dunkard Group bedrock and Ohio River alluvial terrace deposits. The saturated portion of the Ohio River alluvial terrace deposits comprise the principal regional aquifer used for water supply purposes. 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 mid commercial water supply companies obtain water from the alluvial aquifer. The yield from alluvial aquifer wells is related to the well's position with respect to the nver, as well as formation grain size and thickness. The Holocene silts and clays underlying the facility contain perched groundwater zones. 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 3.14). Groundwater elevations for these monitoring wells are typically 6 to 18 feet higher than elevations measured in monitoring wells completed in the underlying pnmary site watertable aquifer. During the February 2002 synoptic water level event, groundwater elevations in the perched water table ranged from 571.91 feet above mean sea level (M5L) to 583.46 feet MSI Groundwater elevations in the underlying pnmary site watertable aquifer ranged from 552.15 to 566.62 feetMSL, Figure 3.1? shows a generalized cross-section for the area of the former Anaerobic Digestion Ponds showing the relationship between the Ohio River (normal pool elevation o f 582.0 feet MSL), the perehed water table, and toe underlying primary site water-table aquifer. The primary site water-table aquifer occurs at a depth o f about 60 to 70 feetbgs m the facility area. The saturated zone is approximately 30 to 40 feet thick, extending to the surface o fthe 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 of the Dunkard Group (Washington Formation^ which consists primarily o f shale and siltstone, bounds the lower extent o f the site aquifer. Natural recharge to the alluvial aquifer comes from various sources, including: a Infiltration o fprecipitation falling directly on the alluvium Q Lateral movement of the river water through the alluvium via permeable sand and gravel zones ' Q Seepage from stream tributaries that discharge to the Ohio River The maximum amount o f water available to toe alluvium depends on the degree of hydraulic connection to the river. The degree of hydraulic connection is a function o f the permeability and thickness of the riverbed, permeability and thickness of the alluvium, and hydraulic gradient between the groundwater and the river. Pumping o f on-site active well fields near and parallel tti the river (i.e., the Ranney Well, the DuPont-Lnbeck 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 Summary - text final Feb. 5 .0 3 Warrington. DE ASH02L650 EID639882 C-8 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 hydrogeologic assessment, 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 transmissivity and the hydraulic conductivity of the primary site aquifer (DuPont, 1990), In the vicinity o f the DuPont-Lubeck Well Field, frtmsmi^mty 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 transmissivity values ranged between 16,050 ana 50 000 gpd/fl?. Hydraulic conductivity values were calculated from the transmissivity vaiues 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 (em/sec) and from 0.01 to 0.049 cm/sec, respectively. ................... ........ ......... ................ Using the hydraulic conductivity values from the 1990 study and the hydraulic gradient values determined from groundwater elevations measured in 1990 and assuming an effective porosity value for sand and gravel o f 35 %, the groundwater flow velocity for several well pairs was calculated. The groundwater flow velocity was estimated at 5 feet/day (ft/d) between monitoring wells T13-MW01 and LI 8-MW01 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 o f the site. In the eastern portion of the site, a groundwater flow velocity o f 2.5 ft/d was estimated for the site aquifer between monitoring wells AL1Q-MW01 and AO09-MW01. Groundwater Flow As part of the C-8 plume delineation work plan, a thorough evaluation of well survey data and well construction data was completed. This evaluation determined that incorrect measuring point 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, the 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 o f on-site production wells. Normal pool elevation for the Ohio River is 582.0 feet MSL, higher than the elevation o f the primary site aquifer, indicating a gradient from the river to the primary site aquifer. The on-site production wells include the Rairney Well, a radial collector well which pumps 800 to 1,000 gpm; the seven wells in the East Well Field, which pump a combined average rate o f2,000 gpm; and the five DuPont-Lubeck wells, which pump about 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 o f the ^ divide and to the west on the western side o f the divide. Groundwater on the western side o f 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 comer of the WWK-C-8 Data S um m ary-text final Feb. 5 ,0 3 Wilmington, DE A SH 021651 EID639883 C-B Data Summary Report W ashington Works Facility site groundwater flows southeast toward the DuPont-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, although preliminary evaluation o f available data indicates a predominantly upward gradient especially near the river that potentially may be reversed near the groundwater mound/dtvtde located under the central and eastern portion o f the facility (see F ip re 3.18). The revised groundwater model supports an upward groundwater gradient between die bedrock and the overlying sand and gravel (DuPont, 2003a). Further data are needed to complete this evaluation and will be collected during future quarterly groundwater monitoring events. Water Quality Groundwater Quality The available C-8 concentration data for groundwater at the site was presented m Section 3 31 These data show that concentrations of C-8 in the groundwater are variable with the highest concentrations being measured in wells screened in the perched water-table located near the former Anaerobic Digestion Ponds. Historic C-8 concentrations m these wells range from less than 100 to 84,100 ug/1. Groundwater from wells screened in the in the perched water table. In addition, C-8 concentrations are variable depending on location of the monitoring well with respect to the locations of the pumping wells. Historic C-8 concentrations in wells located in the eastern half o f 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 u p . Available data for the bedrock aquifer are very limited but range from 0.133 ug/1 in the eastern portion o f the site, to NQ along the 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 representative o f the primary site water-table aquifer Based on measured water elevations in the wells, the perched groundwater in the fine-grained silts and clays o f the Holocene overbank deposits is most likely migrating downward into the underlying site aquifer. The rate of migration of groundwater from the perched water table to the underlying site aquifer is likely to he very slow because of the fine-grained sediments present m this area. Therefore, the contribution o f the C-8 from the perched 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 production wells. 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 significantly below the C-8 SL of 150 ug/1 established by the CATT (WVDEP, 2002). For example, production well AM07-PW01 (historically known as WWK-C-8 D ab Summary - text lira i Feb. 5 .0 3 Wilmington, PE ASB021652 EID639884 C-8 te la Summary Report Washington Works Facility well 336) supplies potable water to the facility, C-8 concentrations in groundwater 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 m Section 3.3.1. The six outfalls monitored at the facility all discharge process water and stormwater runoff to the Ohio River. Outfalls 003 and 007 discharge effluent with the lowest concentrations o f C-8, ranging from NQ to 8.56 ug/1, Outfalls 002,0 0 1 , and 105 discharge higher concentrations ranging from 0.118 to 54.6 utyl. Historically, Outfall 005 has shown the highest concentrations o f C-8 and has discharged a larger volume o f 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 - 8 concentration at Outfall 005 has decreased in 2 0 0 1 and 2 0 0 2 following the installation of a carbon filtration treatment system in the flouropolymers process. Comparing the 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 ALC) o f 1,360 ug/1 shows that all values are lower than the criteria (Menzie-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 o f releases o f C-8 to the environment from 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 the C-8 SL, regardless o f media type. Oil-Site Human Health and Ecological Exposure Pathways . On-site human receptors include authorized facility workers and facility visitors. Ecological receptors include animals living within the facility boundaries. < Direct exposure to C-8 bearing materials contained within the Solid Waste Management Units (SWMUs) is limited or non-existent because thse materials have been removed and regraded or paved (Riverbank Landfill, Burning Ground, Waste Incinerators, and Digestion Ponds) or covered and vegetated. In 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. WW K-C-8 Data Summary - text final Feb, 5 .0 3 Wilmington, DE ) - - '. A SH 021653 EID39885 C-8 Date Summary Report Washington Works Facility A large portion o f 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 -8 impacted soils is an incomplete exposure pathway. Much of the precipitation falling on-site is routed toward drains and storm sewers, which ultimately discharge into the Ohio River. Precipitation falling on the riverbank slope either infiltrates into the soil or runs off to the river. The seeps that occur in places along the riverbank are likely caused by infiltration o f precipitation that accumulates above or in the low-permeability Holocene silt and clay overbank deposits that underlie topsoil and fill along fiie 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 through the 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 (b p ) near the river bank and at 60 to 80 feet bgs under the central portion o f the site. The only potential contact route for groundwater is via contact with water pumped from production wells. Water pumped from production wells is used for two purposes; supplying drinking water and providing industrial process water. Well AM07-PW01 is the production well that provides the majority o f the drinking water to the facility. The other wells that provide drinking water at various times are AOQ8PW01 and AQ09-PW01. Because AMQ7-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 significantly lower than the CATT-established C-8 SL of 150 ug/1 (WVDEP, 2002). In addition, average concentrations of C-8 in drinking water at point o f use (which is a mixture o f 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 o f C*8 measured in these wells was 51.2 ug/1, detected in well V05-PW01. 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 demineralized water to generate steam, and/or consumption in the manufacturing processes. There is a potential for limited contact. However, fins contact is expected to he 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 o f C-8 in process water at the point of use (which is again a mixture o f water from several production wells) will be lower than maximum concentrations detected in any single well. An ecological evaluation conducted as part o f 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/Dgestion Ponds was the only potential ecological exposure medium within the RFI study area. However, topsoil and a vegetation cover WW K-OB Data Summary - text final Feb. 5 ,0 3 Wilmington, DE 22 ASH21 6 5 4 E1D63986 C -8 Dala Summary Report Washington Works Facility prevent human and ecological receptor contact with surface soils (i.e., 0 to 1 feet). Therefore, the contact with surface soil at the Riverbank Landftll/Digestion Ponds ts 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 gravel, asphalt, or buildings and do not provide ecological habitat. Subsurface soil (greater than 2 feet) and groundwater are not exposure media o f concern for ecological receptors, and groundwater does not discharge to surface water at the site. 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 during the groundwater well and water-use survey. West Virginia One- and Two-Mile Radius Groundwater and Surface Water Direct exposure to C-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 to he a complete pathway in situations where the water source is used but the water is not used for drinking-water purposes, although the 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 o f 150 ug/1. The pathway is considered to be complete if the well is used for drinking-water purposes. The highest C-8 concentration measured in drinking water was 2.8 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 considered to be limited due to the low C-8 concentrations measured. An evaluation o f ecological exposure to groundwater and surface water shows that 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 o f C-8 to ecological receptors is limited due to the low C-8 concentrations measured. Ohio One- and Two-Mile Radius Groundwater 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 radios, the highest drinking-water C-8 concentration measured was 8.59 ug/1. This concentration is significantly lower than the C-8 SL o f 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 o f ecological exposure to groundwater and surface water shows that 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 W W K-& 8 Dala Summary - text final Feb. 5 .0 3 Wilmington. DE i SB 02655 EID639887 `\ O B Data Summary Report Washington Works Facility 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 highest C-8 concentration in the Ohio River water, 1.09 ug/1, is well below the C-8 SL. Public Water Supplies The highest C-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 o f C-8 in drinking water supplied to die public. The highest C-8 concentration measured in the drinking water from the Little Hocking well field was 4.29 ug/1. Compared to the CATTestablished C-8 SL o f 150 ug/1, this concentration is significantly below that level (WVDEP, 2002). The human health exposure pathway for groundwater 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 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 facility. The C-8 concentration in groundwater 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 of the data evaluated for the Washington Works facility, the following observations were made: Q 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 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 O Current on-site human receptors contact with C-8 impacted drinking water is a complete pathway. However, this pathway is considered to be minimal because the highest C-8 concentration measured in drinking water at the site was 1.9 W W K-OS Data Summary - text Anal Feb. 5, 03 Wilmington. DE A S H 0 2 6 5 6 EID639888 C-0 Data Summary Report Washington Works Facility (L) ug/1, significantly lower than the CATT-established C-8 SL of 150 ug/1 (WVDEP, 2002). 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. 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 highest C-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 highest C-8 concentration measured was ^ 23.6 ug/1, which is significantly lower than the C-8 SL of 150 ug/1. For Ohio River water, file highest C-8 concentration was 1.09 ug/1, again significantly lower than the C-8 SL of 150 ug/1. The current revised groundwater model supports DuPont's previous conclusions that no off-site migration o f groundwater is known to be occurring and that no potential groundwater migration pathway exists beneath the Ohio River. The current groundwater modeling observations combined with the current C-8 concentrations observed in groundwater, surface-water, and PWS in Ohio indicate that air transport o f C-8 is the primary migration pathway for C*8 from the facility to adjacent areas. C-8 transported in air emissions and deposited on surfaces is likely to be mobilized by precipitation and migrate via water transport to surface water and/or groundwater. Air transport o f C-8 in.air emissions and water transport o f C-8 directly discharging through facility outfalls into the river are believed to be the sources of C-8 in file Ohio River. The highest C-8 concentration measured in Ohio River water was 1.09 ug/1. This C-8 concentration Is significantly lower than the CATT established C-8 ALAC o f 1,360 ug/1 (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. 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. O 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 from C-8 containing materials in the SWMUs directly into groundwater via water transport W W K-G4 Data Summary - text final Feb. S. 03 Wilmington, DE SH021657 110639809 C -8 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 o f 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 approximately 2 feet o f low permeability soil and vegetative cover. Consent Order required tasks to be conducted at or immediately adjacent to the Local Landfill included the following: 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 groundwater wells, springs, and cisterns within a one-mile (and possibly twoand three- mile) radial distance o f the facility and the Local Landfill. Task B : Assessment o f Existing Groundwater and Surface Water Monitoring Data--conducting monthly sampling for C-8 at Local Landfill at certain outfalls identified in WV/NPDES No. WV0076538 as Outfalls 101,004 (Old), 004 (New), 005 (Old)/SS-l, and 005 (New). C-8 samples were to be taken from all fire wells at the Local Landfill monthly for the first four months and quarterly thereafter. Task C: Plume Identification/Groundwater Assessment --determine the vertical and horizontal extent o f C-8 impacted groundwater at Local Landfill exceeding 1 ug/1 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 o f the Consent Order along with the results o f 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 surrounding Local Landfill is presented. 4,2 Task A: Groundwater Well and Water-Use Surveying and C-8 Sampling The Washington Works facility is located immediately north of the Local Landfill. Because o f the proximity o f 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 mid sampling for the facility and the Local Landfill are presented in Section 3.2,1 and 3.2.2. Briefly summarized, expansion o f the one-mile radius was required by the GIST because the C-8 concentrations in five drinking-water samples within the one-mile radius were above the 1 ug/1 threshold 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 WW K-C-0 Data Summary - text final Feb. S. 03 Wilmington, DE ASB021658 EID639890 C-8 Date Summaiy Report Local Landfill establishment o f the human health protective screening criteria for water (C-8 SL) of 150 ug/1 by the CATT, the GIST determined that no further ofT-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 sampled for C-8. The frequency o f sampling was to be monthly for the first four months following the effective date o f the Consent Order, then quarterly thereafter. Monthly C-8 sampling o f groundwater began in December 2001 and quarterly sampling began m May 2002 (2002) Table 4.0 provides a list of the monitoring wells included m the groundwater monitoring program for Local Landfill. Well construction and groundwater elevation data also are provided in Table 4-0- At the time monitoring started, only four monitoring wells existed at Local Landfill, LLMW-4, LLMW-6 , LLMW-9, and LLMW-10. Another five wells were installed during 3Q02 as part o f 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 o f foe monitoring wells. Table 4.1 presents foe C-8 concentrations measured in these monitoring wells, including C-8 data acquired pnor to foe issuance o f foe 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 o f foe limited data set. Additional groundwater monitoring data will be obtained during foe 1Q03 event. However, for foe four wells with multiple C-8 measurements, some observations can be made, and foe results for the new wells can be compared to the historical data available. LLMW-4, LLMW-6 , and LLMW-13B show foe highest C-8 concentrations ranging from 1.32 to 79 6 ug/1 Shallow, overburden well LLMW-11A, only sampled once, had a C-8 concentration o f 2 .2 2 ug/1. The other five wells at foe landfill have lower concentrations, ranging from ND to 1.12 ug/1. The next groundwater-sampling 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/NPDES Permit No. WV0076538) where monthly C-8 sampling was to be performed, Outfalls 101,004 and 005. Monthly sampling of these three outfalls began in December 2001. In March 2002, two additional outfalls were added to the monitoring program due to a modification o f the WV/NPDES permit. [The names o f the two o f 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)/SS-l, not to be confused with Outfall 005 (New).] WWK-C-8 Data Summary - text final Feb, 5 .0 3 Wilmington. DE A SH 021659 1ID639891 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 o f the property and the two 005 outfalls monitor a stream located on the western side o f the property. Both of these streams discharge stormwater runoff from the landfill. Surface water in the two 004 outfalls ultimately discharge to Pages Run, which crosses the facility and enters the Ohio River. Surface water in the two 005 outfalls crosses through the facility in stormwater pipes and ultimately discharges through Outfall 003 to the Ohio River. Outfall 1 0 1 , located along the northeast perimeter of the landfill property, is located in a plastic sewer pipe that conveys seep water and leachate from a series o f three holding ponds located on the eas side of the landfill cells in addition to stormwater runoff. Water passing through Outfall 101 is conveyed via the sewer pipe to the Washington Works facility and ultimately discharges through Outfall 001 into the Ohio River. LM1 (Leachate) is a surface-water point that monitors leachate entering Pond 2, one o f the holding ponds that 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 acquired prior to the issuing o f the Consent Order. The most recent data are listed first for each outfall. Outfall 101 is the only outfall that has consistently had 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/1 range, while the concentration m the both 005 outfalls have been higher, in the 20 to 50 ug/1 range. Outfall 101 has shown a w id e r range of C-8 , from 12 to 115 ug/1. LM l (Leachate) has had the highest C-8 concentration at Local Landfill (120 ug/I). 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 the C-8 results have not yet been validated. The next monthly outfall sampling event is scheduled for February 2003. ' 4.4 Task C: Plume Identfflcation/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 o f the activities recommended in the C-8 plume delineation work plan is summarized. Details of the activity status and the data acquired are then presented. 4.4.1 C-8 Monitoring in Groundwater and Surface Water at Local Landfill 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, was an activity recommended in the C-8 plume delineation workplan (DuPont, 2002e). The results of continued monitoring of groundwater 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 o f C-8 is conducted on a monthly basis. W W K-& 8 Data Summary - text final Feb. 5 ,0 3 Wilmington, OE A SH 021660 EID639892 C -8 Cala Summary Report Local Landfill 4.4.2 Surface-water Field Reconnaissance at the Washington Works Facility Conducting field reconnaissance to identify additional surface-water features located at tire Local Landfill and sampling surface water from new locations identified during llus effort was a C-8 plume delineation recommended activity. Field reconnaissance was performed, and no new surface-water features were identified. 4.4.3 Installation of New Wells at Local Landfill The installation o f four additional well clusters (overburden and bedrock) was proposed in the C-8 plume delineation work plan to further 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 be^ock wells, LLMW-12B, LLMW-13B, and LLMW-14B were installed during 3Q02. The overburden wells were not installed at three o f the proposed well cluster locations because very little overburden was encountered and the overburden was dry. Figure 4.1 shows the locations o f all monitoring wells at the Local Landfill including the locations of the newly instated monitoring wells. Well construction diagrams for the new wells, are provided in Appendix B. The geological logs for the five wells installed in 3Q02 confirm previous interpretations of subsurface conditions at the site. In general, some thickness o f clay and weathered bedrock (shale, sandstone, and/or siltstone) is underlain by unweathered bedrock, which consists of alternating layers o f shale and layers o f sandstone and/or siltstone. Where the data were available, it confirmed that the lithologic units dip slightly toward the north. The new geological data were used to refine the geologic interpretation used 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 o f 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 o f 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 W W K-C-0 Data Summaiy - text final Feb. 5 .0 3 Wilmington, D i ASH021661 EID639893 C-B Data Summary Report Local Landfill bedrock. LLMW-8 , a bedrock welt, 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-1 IB, 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 the 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 installed well, was projected onto BB\ A-A' runs 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 geological data 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 o f approximately 10 to 25 feet at the landfill cells. The slopes appear to be a combination o fnatural topography with terraced outcrops o f massive sandstone and siltstone underlying varying 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 minoT sandy and silty zones, and some pebbles and fragments o f sandstone in some locations. Th clays are o f 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 2 1 to 40 feet bgs, competent bedrock is present (see Figures 4,3,4.4, and 4.5). The bedrock at the Local Landfill consists o f inter-bedded red and varicolored sandy or calcareous shale, and gray, green, and brown sandstone and siltstone o f the Permian age Bunkard Group. Cross-section B-B* (see Figure 4.4) shows that the sandstone layers dip gently toward the north. Most o f the sandstone layers located in the upper portion o f the stratigraphic section are lenticular and laterally discontinuous. However, four laterally continuous sandstone and/or siltstone layers are located in 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 Flew Hydrology fri general, infiltration o fprecipitation is limited due to the very low hydraulic conductivity (5 x 10'7 cm/sec) o f the surficial clays (where these clays exist) and the W W K-C-8 Data Summary --text final Feb. S. 03 30 C-0 Data Summary Report Local Landfill 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 o f the property and one located on the southern side ofthe 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 flows 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 o f 2002, many seeps, which normally do flow, were not observed flowing. The lack of observedflowmayboa result o fthedrought-conditions, teachate from theseponds is - discharged into a pipeline. Monitoring o f combined pond effluent conveyed in the pipeline is 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 o f 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 o f 1 x l ( r cm/sec. The lower sandstone and/or siltstone layers are now identified as the A-Zone, B-2one, OZone, and D*Zone based on re-evaluating the old geologic and 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 through D-Zone are separated by laterally continuous shale layers. Well yields from the sandstone and siltstone 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, this 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 lo w 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 o f the property. - The C-Zone is the next lower sandstone/siltstone unit and is monitored through wells I.LMW-13B and LLMW-14B. The O Zone is located at elevations between approximately 612 and 640 feet MSL. LLMW-11A, located to the south o f one of the landfill cells, may be screened in a weathered portion o f OZone. The screen is located at the correct elevation for OZone, and the lithology there is described as clay overlying silt WW K-C-8 D a b Summary --lexl final Feb. 5 ,0 3 Wilmington, DE 31 A SH 021663 EID639895 # `s C-B Data Summary Report Local Landfill and sand. However, because it is located in a valley, the clay, silt and sand could be recent deposits instead 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 0O4(New), which monitor this stream, were dry during August, September, and October 2002. Based on the data available, LLMW-11A is considered to be part of the C-Zone monitoring wells. The lowest elevation on the north edge o f the Local Landfill and the southern edge o f 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 exposed at the surface but more likely, the edge o f this zone contacts the alluvial material directly. The D-Zone is the lowest hydrogeologic unit encountered, 545 to 562 feet MSL, and is m afe up of siltstone and sandstone. LLMW-1 IB is the only well that was drilled deep enough to encounter the D-Zone; therefore, little information about the lateral continuity o f 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 aquifei (A-Zone) have been prepared from these data as required by the WV/NPDES Permit Ho, WV0076538. Figure 4.6 presents the groundwater elevation map for 4Q02 for the A-Zone. A groundwater elevation map for 4Q02 for th C-Zone is presented in Figure 4.7. Note that data flora LLMW-11A was used to make this map because the outfalls monitoring the stream next to these wells showed no-flow 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 in 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 o f limited groundwater elevation data for the closed wells (based on well installation information) indicates a downward vertical gradient between the upper discontinuous waterbearing zone and the lower sandstone layers containing the underlying significant aquifer (A-Zone). Evaluation of groundwater data for the A-Zone and the C-Zone 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 o f 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 WW K-C-8 Date Summary - text (Inal Feb. 5 .0 3 Wilmington. DE A SH 021664 EID639896 C -6 Data Summary Report Local Landfill 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 discharges to the Ohio River. Groundwater also can seep to small streams draining the property to the north [monitoring points Outfall 005(01d)/SS-l and 005(New)j and flow to the Quaternary alluvial terrace unconfined aquifer where pumping o f on-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 o f the property and ultimately flows toward the north back on to the facility [Outfalls 004(Old) and 004(New)]. Groundwater from C-Zone and D-Zone, which are located in the bedrock at elevations lower than the alluvium surface, likely discharges to the alluvium in the subsurface. Groundwater flow in the alluvial aquifer, adjacent to the valley walls o f the Local Landfill, is toward the pumping wells located near and parallel to the Ohio River. The pumping o f 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. W ater 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 highest at LLMW-4 (maximum o f 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 o f LLMW-4, has shown a range in C-8 concentration o f 0,15 to 1,12 ug/1. Monitoring well LLMW-9, an upgradient well located to the southwest o f one of the landfill cells has shown C-8 concentrations ranging from non-detectatole to 0.14 ug/1. These data indicate that C-8 from 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 gradients indicate 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, groundwater flow with the B-Zone is toward the facility in the northwest and away from the one- and two-mile sampling area. C-8 concentrations for the one round o f data for wells in the C-Zone, LLMW-] 1A, LLMW-13B, and LLMW-14B, are higher, 2.22,6.61, and 0.488 ug/1, respectively, supporting a downward vertical gradient for groundwater from the A-Zone to the B-Zone to the C-Zone as indicated by groundwater elevations. Groundwater flow in the C-Zone is likely to be in the same direction as in the A-Zone and the B-Zone, to the northwest. The one C-8 value from the D-Zone is HQ (LLMW-1 IB). This may indicate that downward migration o f C-8 to the D-Zone has not taken place. However, the location of this well is upgradient o f the landfill cells WW K-C-fl Data Summary -te x t final Feb. 5 .0 3 33 C-B Data Summary 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 o f this northwest flow direction. . Surface-water Quality C-8 concentrations in surface water are presented in Table 4.2. Outfall 101 monitors stormwater runoff and effluent from the leachate ponds and seeps that dram into the ponds. Outfall 101, which has never had no-flow conditions while it has been monitored, has had the highest C-8 concentration measured in surface water at Local Landfill, ranging from 12 to 115 ug/1. The C-8 concentration measured in a sample from Inlet 002 [LM1 (Leachate)], which collects seep water flowing to Pond 2, was 120 ug/1, in November 2002. Outfalls 004(Old), 004(New), and Q05(Old)/SS-l and 005(New) are monitoring points , located along two streams on the southern and northern sides o f the property, respectively. These outfalls collect stormwater runoff from the landfill cells. These four outfalls have all had no-flow conditions for the past several months. However, Outfall Q05(Old)/SS-l historically has shown the highest C-8 concentrations of these four . outfalls, ranging from 6 .8 to 51.4 ug/1. 4J .2 Current Human Health and Ecological Exposure Pathways The main objective of the Consent Order was to determine whether than has been an impact on human health and the environment as a result o f releases o f 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 on-site (at the Local Landfill) and off-site (adjacent to 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-Site Human Health and Ecological Exposure Pathways Current Environmental Setting This section describes file 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 o f the landfill property. The trail loops around the eastern part o f the landfill starting and WW K-C-8 Data Surmnaiy - text final Feb. 5 ,0 3 Wilmington. DE A SH 021666 EID639898 C"B Dala Summary Report Local Landfill ending near the landfill's electrically operated gate. The nature trail is a marked trail an does not come near the cells. Access to the site from surrounding roads is possible hut 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 permeability soil and vegetative cover. This cover prevents human and ecological receptois' exposure to the landfilled materials. Permit WV0Q76538 requires that the landfill surface will be inspectai quarterly for evidence of cracking or erosion (which could allow surface water to enter the solid waste deposit) and evidence o f settling of solid waste (causing ponding o f surface water). Per Condition G-16 o f the permit, a stormwater erosion inspection is conducted annually. Therefore, human and ecological receptors exposure to C-8 containing landfilled materials is an incomplete pathway. At the landfill, precipitation is expected to take one o f two paths. It may infiltrate downward through the vegetated soil cover and into th cells, although, the low ^ permeability o f 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 to rn further 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 although the amount o f 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 x ecological receptors. However, contact would be very rare since only facility representatives enter this area on an infrequent basis. The highest C-8 concentration measured in leachate from Local Landfill 120 ug/1, which is lower than the CATTestablished C-8 SL o f 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 o f 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 W W K-C-ii Dato Summary --text final Fb. 5, 03 Wilmington, DE A SH 02X 667 i EID639899 C -8 Data Summary Report Local Landfill 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/1 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 mid 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 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 impacted media: On-site landfilled materials * On-site soil ' On-site groundwater . O 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 limited because o fhealth and safety practices followed when managing the leachate and because o f 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-establisbed C-8 SL o f 150 ug/1 and the Aquatic Life Advisory Concentration for C-8 (C-8 ALAC) o f 1,360 ug/1 (WVDEP, 2002; Menzie-Cura & Associates, 2002). Q Current off-site exposure pathways for human and ecological receptors that are complete hut limited, due to the very low C-8 concentrations measured, include residential drinking and non-drinking-water sources. For the drinking and non drinking-water sources, the highest C-8 concentrations measured were 2.8 and 5.07 ug/1, respectively. These concentrations are well below the C-8 SL of 150 ug/L . Evaluation o f 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 deposited on surfaces is likely to be mobilized by precipitation and migrate via water transport to surface water and/or groundwater. WW K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington, DE A SH 021668 EID639900 0 *8 Dala Summary Report Letart Landfill 5,0 LETART LANDFILL 5.1 Introduction The Letart T ^ f i l l is located about 46 river miles downstream o f the Washington Works facility, north o f the town of Letart in Mason County, West Virginia (see Figure 5.0). The landfill was operated and closed under WV/NPDES Permit No. WVQ076066. The Letart Landfill was permanently closed by installing an engineered multi-layer geosynthetic and soil cap (DuPont, 2001). Included in the closure activities were the installation o f a leachate collection system, erosion and drainage control measures, and chain-link fencing. The cap construction was completed in April 2001. The permit requires quarterly 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 the following; 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 Letart Landfill. Task B: Assessment o f Existing Groundwater and Surface Water Monitoring Data---conduct monthly sampling for C-8 at Letart Landfill at certain outfalls identified in WV/NPDES Permit No. 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. Task C: Plume Identification/Groundwater Assessment--determine the vertical and horizontal extent o f C-8 impacted groundwater exceeding 1 ug/l or as directed by the GIST at Letart Landfill. This task included an assessment o f the C-8 concentration in Ohio River Water in the vicinity o f the Letart Landfill. In Sections 5.2 through 5.4, discussions are presented of the specific activities that were conducted to meet the requirements o f the Consent Order, along with the results o f the sampling events. 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 Weil and Water-Use Surveying and C-8 Sampling The groundwater well and water-use survey and sampling activities conducted within the one-mile radius o f the Letart Landfill were completed on February 24,2002. DuPont submitted the results o f the one-mile radius survey to the GIST in April, 2002 (DuPont, 2 0 0 2 a). W W K -C e Date Summary - text final Feb. 5 ,0 3 Wilmington, DE ASE021669 EID639901 i\ C -8 Dat Summary Report Letart Landfill Table 5.0 summarizes the off-site surveying and sampling program for the one-mile radius. A total o f46 homes were surveyed, and a total of 30 wells were sampled. Eleven of the wells were used as drinking-water sources. Table 5.1 provides details for each sample collected including the C-8 concentration measured (ug/1). Eight other wells sampled were used for non-drinking water and the other 11 wells were unused. No cisterns or springs were sampled. Figure 5.1 shows the locations sampled, regardless o water use. Each colored circle represents a sampling location, and the color and size of the circle indicate the magnitude 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 samples were ND or NQ, except for one sample collected from a well used for drinking water that had a C-8 concentration of 0.139 ug/1 and one sample collected from an unused well that had a concentration o f0.636 ug/1. The GIST required that the drinking-water well sample with a C-8 concentration of 0.139 ug/1 be 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 further surveying and sampling was needed. 5.3 Task B: Assessment of Existing Groundwater 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. Montiily C-8 sampling o f groundwater began in December 2001 and quarterly sampling began in May 2002. Table 5.2 provides a list o f 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 o f the C-8 plume delineation work. These wells were included in the monitoring program that began in 4Q02. Figure 5.2 shows foe location o f foe monitoring wells. Table 5.3 presents foe C-8 concentrations measured in these monitoring wells, including C-8 data generated prior to the issuing o f the Consent Order. The most recent data are listed first for each well. The water-bearing units at foe 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 foe 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 edge o f foe 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 ,0 3 38 A SB 021670 EID639902 C -8 Data Summary Report Letart Landfill Groundwater 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 tl^ u g h LMW-3 and LMW-5A. C-8 concentrations in LMW-3 and LMW-5A ranged from NQ to 2,270 ug/1 and from 0.8 to 112 ug/t, respectively. Note that in the groundwater elevations measured for LMW-5A (see Table 5.2) have always been at depths lower than the bottom o f the screen indicating that this well has been essentially dry throughout the penod it has been monitored. Groundwater sampled from this well and analyzed for - 8 may not be representative o f 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 m LMW-3A a n d l 3A ranged from 60.3 to 510 ug/1. C-8 concentrations measured in LMW-4, -5B and -14A ranged from 172 to 3,060 ug/1. LMW-12 was dry during the 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 LMW-10, LMW-l 1, and LMW-13B have always been less than 1 ug/1. Concentrations of C-8 in LMW-6 ranged from 9.4 to 30 ug/1. C-8 concentrations in LMW-2A and -14B ranged from 50 to 990 ug/1. An additional sandstone and siltstone zone, located under the F-Zone is monitored by LMW-9. The C-8 concentrations measured in LMW-9 ranged from 0.2 to 0.907 ug/1. Table 5.2 shows that groundwater elevations in this well have consistently been below the bottom o f the screen, indicating that this well has essentially been dry during the period that is has been monitored. In 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 ug/1) 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 stormwater runoff from the landfill. Outfall 002 then discharges to a small wet-weather stream at the toe o f the landfill. Outfall 003 collects stormwater runoff. Monthly sampling of these two outfalls began in December 2001. DuPont also is sampling surface-water samples at selected other locations, including Stormwater Runoff, Rt. 33 Stream, Blinkers Run and Cap Runoff. Figures 5.2 and 5.3 show the locations o f the six surface-water sampling points. Table 5.4 gmnmariyfts the C-8 concentrations measured in the outfalls, including C-8 data generated prior to the issuing o f the Consent Order. The most recent data are listed first for each outfall. Outfall 002 collects landfill leachate. C-8 concentrations at this outfall have ranged from 4.52 to 3,240 ug/1. Using the 14 (see 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/1. The C-8 concentrations in this leachate have been highly variable since the landfill cap WW K-C-8 Date Summary - text final Feb. 5 ,0 3 Wlimlrigton. DC ASH021671 EID639903 *) C -8 Dala Summary Report Letart Landfill was installed. Cap Runoff C-B concentrations ranged from 65.1 to 371 ug/1. The Stormwater Runoff sample had a concentration of 50.9 ug/1 The R ^ B Stream Oulfall 003, and Blinker's Run samples' C-8 concentrations ranged from 0.0612 to 3.92 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 the C-8 results have not yet been validated. The next monthly outfall sampling event is scheduled for February 2003. 5,4 Task C: Plume ldentificatien/Groundwater Assessment Based on the data gaps identified in the Compilation of Historical C-8 Data Report (DuPont, 2002b), the C-8 Plume Identifieation/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 o f the activities recommendedin the C-8 plume delineation work plan are summarized. Details of die activity status and the data acquired are then presented. In addition, 1asK C included an assessment o f the C-8 concentrations in Ohio River Water m the vicinity o f the Letart Landfill, and these results also are presented. 6,4,1 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 m the Consent Order. The results of continued monitoring o f groundwater and surface water are presented in Section 5.3.1. Monitoring o f C-8 in groundwater continues on a quarterly basis, while surface-water monitoring o f 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 performed, and no new surface-water features were identified. 5.4.3 Installation of Now 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 farther 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 3Q02. At LMW-12, no overburden was encountered. Figure 5.2 shows the locations of all monitoring wells at the Letart Landfill including the locations o f the newly installed monitoring wells. Well construction diagrams for the new wells, are provided in Appendix C. W W K-C-8 Dala Summary - text final Feb. 5, 03 Wilmington, DE ' ASH021672 ED639904 C-8 Data Summary Report Letart Landfill Data from the geological logs For the five wells Installed in 3Q02 support the previous interpretation o f subsurface conditions at the site. Clay and weathered bedrock (shale, sandstone and/or siltstone) is underlain by bedrock, consisting of alternating layers o f shale and sandstone, or siltstone or both. The A-Zone through the 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 geologic data confirmed that the lithologic units dip slightly toward the south. The new geological data were used to refine the geologic interpretation used for the revised SCM, which is presented m 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 Integration of all the new data gathered during completion of Tasks A, B, and C into a revised SCM. This activity was completed, and the revised SCM is presented in Section 5.5. 5.4.5 Ohio River Water Sampling Near Letart Landfill Adjacent to the Letart Landfill, Ohio River water also was sampled to measure the C-8 concentrations. Two locations were sampled. These sampling locations are shown m Figure 5.4. One sampling location was positioned in the river near the point where the ravine originating at the landfill discharges surface water into the river. The other sampling point was located approximately 1,0 0 0 feet downstream of the first location. Ail samples were collected near the shoreline (approximately 100 feet east o f the shoreline). Dip and mid-column samples were collect! at both locations. In total, five river-water samples were collected, including one duplicate sample. The Ohio River water C-8 results For samples collected near the Letart Landfill are presented at the bottom o f Table 3-11 and are shown in Figure 5.4. 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 bettor 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 F-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, f> WW K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington, DE SB021673 EID6399Q5 C*8 Data Summary Report Letart Landfill to further delineate C-8 concentrations in groundwater, and to evaluate groundwater flow direction. The locations of four cross-sections developed for the Letart Landfill are shown in Figure 5.5. Two cross-sections, A-A' and B -B \ were presented in the Compilation o f 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 rad runs south, showing the geological data obtained from the newly installed monitoring wells. The Letart 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, 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 o f 20.5 feet. The underlying bedrock at the Letart Landfill consists o f interbedded red and varicolored sandy or calcareous shale, and gray, green, rad brown sandstone and/or siltstone of the Permian age Dttnkard Group. Six stratigraphic water-bearing zones that were designated as the A-Zone through F-Zone, with the A-Zone being the shallowest zone rad the F-Zone the deepest. These zones are identified on the cross-sections. These zones consist of massive, very fine to fine grained crystalline sandstone and/or siltstone with occasional shale lenses. The A-Zone through the F-Zone are separated by 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-2one are a single'zone In the far north rad separate into two distinct zones in the central area. The B-Zone thins out rad is missing from logs from file southern area. D-Zone is an isolated unit in the northern area. This unit joins up with B-Zone m the central area. In the southern area, the D-Zone rad 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, rad LMW-5B were re-examined during construction o f new cross-sections rad are now believed to be screening other 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 fins newly identified zone, it is not dear if this 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 Groundwater Flow Hydrology The Letart Landfill engineered cap system prevents surface water from contacting landfilled materials. Precipitation falling on the engineered cap system takes one o f two paths. It may infilfrate downward through the vegetated soil rad encounter the impermeable geomembrane and then flow laterally downslope on top of the geomembrane. Alternatively, precipitation may flow via overland flow on top o f the vegetative layer downslope. In either situation, this surface water does not contact the WW K-C-a Date Summary - text Anal Feb. 5 .0 3 Wilmington, DE ASH021674 EID639906 C-8 Data Summary Report Letart Landfill landfilled materials and migrates downslope toward drainage ditches constructed m or adjacent to the cap system. Precipitation falling on the northwest side of the upper part of the cap flows downslope toward the southwest, away from the landfill, into a drainage ditch that flows to a sediment trap near LMW-6 . Precipitation falling on the remaining portions of the cap flows downslope and toward the south in drainage ditches. Hydrogeology Hydraulic conductivity testing [i.e., slug tests (A-Zone) and borehole packer tests (Z one, D/E-Zone, and F-Zone)] of the bedrock zones indicates that these zones display low hydraulic conductivity (Tetra Tech Richardson, 1990). Hie A-Zonehydrauhc conductivity is low, ranging from Iff4 cm/sec to less than Iff cm/sec. (There are no wells monitoring the B-Zone; therefore, it was not tested.) The C-Zone and F-Zone have very low hydraulic conductivities ranging from 1 0 cm/sec to less than 1 0 cm/sec. The D/E-Zone hydraulic conductivities also are very low and range from 10 cm/sec to 10'cm/sec. The low hydraulic conductivities can be attributed to the very fine-grained nature o f the water-bearing units. In addition, many sandstone units in the region typically display effective porosity as low as 1 percent. This low porosity results from pore space being filled in by authigenic minerals (e.g., kaolimte) sometime after original sediment deposition. The F-Zone has been designated the "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 hydraulically connected 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 HdffltfttP.it 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 F-Zone. The saturated thickness o f 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). ha 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 essentially be 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 .1 0 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 WWK-C-8 Data Summary - text final Feb, 5 .0 3 Wilmington, DE 43 EID639907 C -8 Data Summary Report Letart Landfill 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/E-Zone, two wells that monitor this zone were not used. The D/E-Zone becomes quite complicated in the southern portion of the landfill area. In the very northern arei&, the D/E-Zone does not exist. In the north-central portion of the landfill area, the D/E-Zone appears as a single lithological unit. In the south-central part, the D/E-Zone splits into a thinner upper unit and a thicker lower unit. At the toe of the landfill are ttaee wells that monitor the D/E 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 constructing the groundwater elevation map because the elevations that were observed in these wells were not thought to be representative o f overall groundwater flow within this zone, hi general, ground water flow in this zoiie is from the north toward the south. F ip re 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 o f the landfill, groundwater 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 o f the bottom of the 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 o f groundwater flow directions within these zones. However, elevations measured in the monitoring wells indicate a downward vertical gradient within the.sitepoundw atosystan............... .................................................... -.................. system in 2 0 0 1 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 o f the 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 o f the valley. The landfill is an unlined W W K-OS Date Summary - text te a l Feb. 5 ,0 3 Wilmington. DE A SH 021676 S ID 639908 C -8 Dala Summary Report Letart Landfill landfill. This means that C-8 impacted water migrating through the landfilled matenal 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 overa 1 downward g ^ ie n t f r ^ t h e 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 installationoffire engineered cap will minimize the amount o f precipitation able 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 expected given tha the C-8 concentration in the landfilled materials was most likely higWy variable. In the A-Zone, LMW-1 shows the highest concentrations; and, m general, w eL -8 concentrations appear to be increasing over time 7^ L ' concentrations have been higher in LMW-3 than m IM W -5 ^ In , highest C-8 concentrations are found in LMW-4 and LMW-5B, both located at the toe of the landfill. In 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 momtors a zone lower than the F-Zone, C-8 concentrations have always been less than 1 ug/1. C-8 concentrations in groundwater from 28 residential ^ l o c a t e d vritWn 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 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. T h e O J^ u g /l sanple is located amongst many other samples that had C-8 concentration ofND N Q . The location o f the 0.636 ug/1 sample is almost the same location as where the R t 3 3 Strea sample is collected. C-8 concentrations in the RL 33 Stream sample p r a n g e d from 0 573 to 3.92 ug/1. It is possible that this well is m communication with C-8 impacted surface water at this location. The stream that is being sampled does receive surfacewater runoff from the landfill. The C-8 concentration measured withm the One-mile radius are significantly lower that the CATT-established C-8 SL a of 150 ug/1. In the Compilation o f Historical Data Report (DuPont, 2002b), the annual loadingofC -8 to die Ohio River from C-8 impacted-groundwater at Letart Landfill was calculated. The estimation was based on the assumption that impacted groundwater flows from the A-Zone downward to the F-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 loading was l 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 m 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/1, higher than the previous mean used. Therefore, the revised annual loading estimate is 0.017 Ib/yr, also higher than previously estimated. Therevised annual loading also should result in a very low concentration in the Ohio River. The WWK-C-B Data Summary - loxt final Feb. 5 ,0 3 Wilmington. DE ASH021677 EID639909 C -8 Data Summary Report Letart Landfill measured C-8 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/1 and 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. Sampling locations, Outfall 002, Cap Runoff, and Stormwater Runoff are associated with leachate from the landfill and have had the highest C-8 concentrations measured in surface water at the Letart Landfill. Cap Runoff and stormwater runoff have 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 that have ranged from 4.52 to 2,050 ug/1 since 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 Blinker Run sample, which was collected from a stormwater drainage ditch, had a very low C-8 concentation, 0.0612 ug/1. Stormwater runoff from the northern part o f the landfill flows down the stormwater drainage ditch, off the F pedy and into Blinker's Run. Brinker's Run discharges into a pond that is located off the north side of the landfill property. The Rt. 33 Stream sample is collected at the point where Brinker's Run enters the pond. The C-8 concentrations for the RL 33 Stream samples have ranged from 0.573 to 3.92 ug/1. The pond then discharges to the Ohio River. Other than Outfall 002 and Cap Runoff samples, all the surface-water samples for the Letart Landfill am less than the drinking water and the C-8 ALAC (WVDEP, 2002; Menzie- Cura & Associates, 2002). 5.5.2 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 o f releases of C-8 to the environment from DuPont operations at die Washington Works facility and the associated landfills (Local, Letart, and Dry Run). Therefore, human health and ecological exposure pathways both on-site (at the 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 on- and off-site. Potential exposure routes were evaluated and classified as complete or incomplete. Table 5.5 summarizes the human health aid ecological exposure pathway evaluation for the Letart 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 o f media type. On-Site 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 WW K-C-8 Data Summary - text final Feb. 5 ,0 3 Wilmington. D i 46 B1D639910 G-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 designed to convey the runoff from the landfill cap to a designated discharge point and to eliminate die potential for runoff-related erosion of the cap. In addition the landfill cap is requued to be inspected at least quarterly (permit requirement C.12.A) For evidence of iBr0TM1" the landfill's Stormwater Pollution Prevention Plan. The engineered cap 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 landfilled materials and soils is considered an incomplete exposure pathway to human and ecological receptors. The Letart Landfill engineered cap system also prevents surface water from contacting landfilled materials. Surface water flows toward drainage ditches constructed in the cap system and is discharged at the southern edge o f the landfill. Because this surface water does not contact the landfilled materials, it is not impacted by C-8 However, leachate discharging from the leachate collection system is piped to Outfall 002 (leachate basm), where it mixes with stormwater runoff. Outfall 002 enters a OTiall, wet-weather stream that flows approximately 400 feet before it discharges to the Ohio River. However, exposure is limited because o f the remote location of the landfill, the very steep terrain, and the wet-weather nature o f 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. The highest C-8 concentration measured in leachate since the installation o f 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 was 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 o f the valley walls and would only be exposed at the surface if seeps exist. Field reconnaissance did not identify any seeps m 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 highest C-8 concentration in a non-drinking-water sample was NQ, well below the C-8 SL o f 150 ug/1. The pathway is considered to be complete if the well W W K-C-8 Data Summaiy - text final Feb. 5 ,0 3 Wilmington. DE ASH021679 EID63991 C -8 Data Summary Report Letart Landfill is used for drinking-water purposes. The highest $ ,,8 water was 0.139 ug/l, significantly lower than the CATT-established C-8 SL o f 15 (WVDBP, 2002). Therefore, even though the pathway is complete, it also is limited due tr, thft Inw 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 impact on human healthand the environment as a result o f releases of C-8 to the environment from the landfill. The C-8 concentration m groundwater and surface water from many sources (on-site, off-site, monitoring wells, production wells, private wells, and Ohio River water) was measured. Based on all ofthe data evaluated for the Letart Landfill, the following observation were made: The current exposure pathways are incomplete for human and ecological receptors contact with the following C-8 impacted media: * On-site landfilled materials * On-site soil * On-site groundwater Q Human and ecological receptors contact with C-8 impacted surface water and leachate (Cap Runoff and Outlet 002) discharging to the wet-weather stream at the toe ofthe landfill are currently complete exposure pathways. The highest C-8 concentrations measured at these locations are 371 and 2,050 ug/l, respectively. However, exposure is limited because of the remote location of the landfill, the very steep terrain, and the wet-weather nature o f the stream. In addition fencing limits access to the area. Further, the use o f health and safety plans, standard operating procedures, and personal protective equipment also limit exposure. Q 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 non-drinking-water sources, the highest C-8 concentrations measured were 0.139 and NQ, respectively, which are well below the C-8 SLoi 150 ug/l (WVDBP, 2002). The highest C-8 concentration measured m Ohio River water is 0.128 ug/l, well below the C-8 SL of 150 ug/l and the 1,360 ug/l C-8 ALAC developed by the CATT (Menzie-Cura & Associates, 2002). Groundwater flow in the site significant aquifer under the landfill is toward the southwest and the Ohio River. C-8 impacted groundwater from the water-beanng zones at Letart Landfill ultimately flows into the Ohio River. Evaluation ofthe groundwater flow directions at the landfill and ofthe Letart onemile radius C-8 results shows that C-8 impacted groundwater is not migrating toward off-site residences. 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 WW K-C-8 Data Summary - text final Feb. 5 .0 3 Wilmington. DE 48 ASH021680 EXD639912 C -8 Data Summary Report Letart Landfill (0 128 ug/j) that are well below the C-8 SL and the C-8 ALAC th atwer determined by the CATT (WVDEP, 2002; Menae-Cura & Associates, 2002). The transport pathway of C-8 at the Letart Landfill is believed to be via water transport from C-8 containing landfill materials. Air emission of C-8 as a migration pathway is not possible because there are no air emissions at the Letart Landfill. In addition, the Letart Landfill is too far away from the Washington Works facility to be impacted by C-8 containing air emissions emanating from the facility. WWK-C-B Dala Summary - text final Feb. 5 .0 3 Wilmington, DE ASH021681 EM39913 C -8 Data Summary Report Dry Run Landfill # 6.0 DRY RUN LANDFILL 6.1 Introduction The Dry Run Landfill is located west of the town of Lubeck, in Wood County, West Virginia, about eight miles southwest of the Washington Works facility and the Local Landfill (see Figure 6.0). The landfill covers approximately 17 acres of a 5 3 5 -acrc parcel o f land owned by DuPont. The landfill was constructed within the drainage basin of Dry Run, a tributary of the North Fork of Lee Creek, which is a tributary o f the Ohio River. The landfill began operation in 1986 and the central portion is still active and operates under WV/NPDES Permit No. WV 0076244. The upper portion o f the landfill is closed and is covered with a soil and vegetative cover. The lower portion o f the landfill also is closed and is covered by a engineered landfill cap. Consent Order required tasks to be conducted at or immediately adjacent to 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 Tsmdfill Task B; Assessment o f Existing Groundwater and Surface Water Monitoring Data--conduct monthly sampling for C-8 will be performed at 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 the wells at the Dry Run Landfill monthly for the first four months and quarterly thereafter. Task C: Plume Identificafion/Groundwater Assessment--determine the vertical and horizontal extent o f C-8 impacted groundwater exceeding 1 ug/1 or as directed by the GIST at Dry Run Landfill. In Sections 6.2 through 6.4, discussions o f the specific activities conducted to meet the requirements o f the Consent Order are discussed along with the new data generated during these activities, hi Section 6.5, 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 surrounding the Dry Run Landfill is presented. 6.2 Task A: Groundwater W ell 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 Run 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). WW K-C-8 Date Summary - text Baa! Feb. 5, 03 Wilmington. DE ASB021682 EID639914 G-8 Data Summary Report Pry Run Landfill Table 6.0 summarizes the off-site surveying and sampling program for the one-mile radius A total o f 64 homes were surveyed, and a total of 53 water sources (wells, cisterns and springs) were sampled. Thirteen wells, one cistern, and one spnng sampled 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 o f all samples collected, regardless of water use. Each colored circle represents a sampling location, and the color and size of the circle indicate the magnitude o f the G-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 the Dry Run Landfill one-mile radius samples . were less than 1.0 ugfl. The highest C-8 concentrations measured for unused and non drinking-water sources were 0.974 and 0.54 ug/1. Seven of the 15 drinking-water samples were ND or NQ, and the range of C-8 concentrations in the other eight drrakmgwater sam ples w as between 0.0505 and 0.339 ug/l 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 resampling of 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 o f the three drinking-water sources was completed in April 2002. C-8 concentrations ranged from NQ to 0.422 ug/1 in 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 o f 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 o f the landfill, discharges surface water to die 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 0.331 ug/1, respectively. 6.3 Task B: Assessment of Existing Groundwater and Surface-water Monitoring Data 6.3.1 Monitoring of C-8 in Groundwater and Surface Water at Dry Run Landfill Groundwater Monitoring The Consent Order required that all monitoring wells at Dry Run Landfill be sampled for C-8. Monthly C-8 sampling o f groundwater began in December 2001, and quarterly sampling began in May 2002. Table 6.2 provides a list of the monitoring wells included in the groundwater 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 Run Landfill. Another seven wells were installed during 3Q02 as part o f the C-8 plume delineation work plan, and these new wells were included in the monitoring program starting in 4Q02 (DuPont, 2002k). W W K-C-8 Data Summary - text Anal Feb, 5 ,0 3 Wilmington, DE ASH021683 ED639915 C -8 Data Summary Report Pry Run LandfiH 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 issuing of 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 depth as 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 shown the highest C-8 concentrations in overburden, ranging from 0.07 to 15 Ug/l. This well is located at the toe o f the landfill. DRMW-6A has shown a C-8 concentration range o f 0.096 to 1.24 ug/l. DRMW-12A, DRMW-12B, and DRMW-21A have had much lower C8 concentrations, ranging from ND to 5.4 ugh. Wells monitoring the A-Zone include DRMW-16B, DRMW-17B, DRMW-18B, DBMW-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 o f these wells are new wells, except DRMW-14, and have only been sampled one time. C-8 concentrations in these new wells has ranged from ND to 0.155 ug/l. C-8 concentration in DRMW -14 has ranged from <0.1 to 2,5 ug/l. Wells monitoring the 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-15 has had higher C-8 concentrations ranging from 0.263 to 5.0 ug/l. 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/l. Only one well monitors the C-Zone, DRMW-21B. This is a new well that has only been sampled once, 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 outfalis at the Dry Run Landfill (regulated by WV/NPDES Permit No. WV0076244) where monthly C-8 sampling was to be performed, Outfalls 001,003, and 004. (Outfall 002 is a required outfall sampling location as stated in die WV/NPDBS 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 sampling o f these three outfalls began in December 2001. 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 Underdrain, Property Boundary, and DR Leachate, The locations o f die 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 o f the Consent Order. The most recent data are listed first for each outfall. miK-OS Data Summary - text final Feb. S, 03 Wilmington. DE ASH02184 110639916 C -8 Dala Summary Report Dry Run Landfill point. O ^O M h k h rf^fto w co p d M o M m lO ^ X h samptes uM k takan, tl C-8 coneenM io 0 7 .. 58 u * m n g it diffic to determine arepreaentative C-8 f " f ahoTM k ,M f , i 5 The & 8 TM f* 'although Outlet 0G3 has had no-flow conditions in nine of the 12 sampling events ^The Outlet 001, SS-2 and Pond Underdrain sampling locations have s wn concentrations ranging from 4.6 to 8? ug/1. The DR Leachate sampling point, from w hichl^chate ^etaacdw lo^ 8 iscaptured by the leachate collection system at Diy Run and is transported to t c S S ^ ES S S sE'Washington Works facility where it is treated. sampling event is scheduled for February 2003. 6 4 Task C: Plume ldentlflcation/Groundwater Assessment (DuPont, 2vv h ni<!T /DuPont 2002e). Included in this work plan were the activities recommended in the C-8 plume delineation work plan is summarized briefly. Details o f the activity status and the data acquired are then presented. 6.4.1 C-8 Monitoring in Groundwater and Surface Water at Dry Run Landfill Continuing to monitor C-8 in groundwater in the overburden rad in the ` bedrock aquifer (utilizing the newly installed momtanng wells), rad m surfaceT'J'T pristine locations identified in the Consent Order, was an activity recommended m the C 8 Dlume delineation work plan. The results o f continued monitoring of groundwater 2 2 L E T p r e S e d in Section 6.3.1. Monitoringof C-8 in groundwater miarterlv basis while surface-water monitoring o f C-8 is conducted on a rnl% bsi!P pre-existing surface-water monitoring points. The Dry Run creek Ogres '* iradfill rad then discharges to Lee Creek, which dischrgts to the Ohio River. This sample was collected, rad the C-8 results r e presented in Section 6.3.1. e WWK-C-B Data Summary - text final Feb. 5 ,0 3 Wilmington, DE 53 SH021685 1ID6399JL7 C -8 Data Summary Report Dry Run Landfill 0,4.2 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 sampling surface water from new locations identified dunng this effort was a C-8 plume delineation recommended activity. Field reconnaissance was performed (during drought conditions) 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 proposed in 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 wellcluster 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 o f alternating layers of sandstone and siltstone separated by layers of shale. Further, the new geologic logs also confira 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 integration o f all the new data gathered during completion o f Tasks A, B, and into a revised SCM. This activity has been completed, and die 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 die conditions at and surrounding the Dry Run Landfill. The following sections present the revised SCM in detail. 6.5.1 Current Environmental Setting Geology The locations o f 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 o f the new wells installed in 3Q02, was generated. This new cross-section WW K-OB Dala Summary--text final Feb. 5 .0 3 Wilmington, DE A SH 021686 EID639918 C -8 Data Summary Report Dry Run Landfill A-A' which runs northwest to south east along the northeast side o f the landfill, is presented in Figure 6.4. Cross-section B -B \ running north to south across the toe o f the landfill, has been modified slightly but the basic information m the cross-section remain. The modified cross-section B-B' is presented in Figure 6.5. In 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 o f the landfill. Cross-section D-B' runs across the center o f the landfill crossing from the northeast to the southwest. The Dry Rim 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, consisting primarily o f heavy clays derived from the weathering o f shale, A geotechnical investigation of the overburden underlying the Dry Run Landfill was completed by DuPont (1996). The investigation consisted o f advancing soil test bonngs, test pits, laboratory testing of soil physical properties, 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 o f this natural soil ranged from 12 to 28 feet in the test borings within the landfilled area. In 1989, a monitoring well installation program, performed by Tetra Tech Richardson Inc., indicated similar silty clay and weathered shale overburden. Currently, there are five monitoring wells that monitor the water-bearing overburden (DRMW-6 A, DRMW-12A, DRMW-12B, DRMW-13A, and DRMW-21 A) at the Dry Run Landfill (see Figures 6.4 through 6 .6). - ... , _____ 11* fWr, nTvntrwimntelv 1? to 20 feet bgS. The underlying bedrock at the Dry Run Landfill consists o f inter-bedded red and varicolored sandy or calcareous shales, and gray, green, and brown sandstones and/or siltstones o f the Permian age Dunkard Group. Based on the new geological data, three separate water-bearing siltstones and/or sandstone units have been identified withmthe bedrock at Dry Run. These zones are shown on the cross-sections when possible. These are labeled the A-Zone, the 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 o f the landfill area, while the B-Zone is known to be laterally continuous under the toe of the landfill in the northwest. None o f the new wells were drilled deep enough to encounter the C-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 furthest 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. WW K-OO Pala Summaiy - text final Feb. 5 .0 3 W am ington.DE A SH 021687 EID639919 C -6 Data Summary Report pry 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 encompassing the inactive lower half o f the landfill was completed by Potest & Associates, Inc. in 1999. Leachate from the landfill discharges mto a leachate collection sump located northwest o f the landfill (see Figure 6.2) through perforated pipes buried at the low edge o f the fill area. The leachate is pumped from the collection sump to a 50,000-gallon collection tank located at the top of the hill. Leachate is pumped from the collectira tank to a tanker truck, which is then hauled to the facility for treatment m the wastewater treatment plant. Six surface-water sampling points are located near the toe o f 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 o f the landfill. Ultimately, al o f 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 underlying bedrock 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, Inc. as required by the permit because these wells were not being utilized for quarterly monitoring (Potesta & Associates, 1999). Groundwater Flow In the 4002 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 conceptual model 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 the 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 o f groundwater flow in the B-Zone. The groundwater contour lines on this map are dashed because there are very limited data for the zone. However, groundwater flow direction in this zone also is generally toward the west. Groundwater flow directions m the underlying the C-Zone cannot be determined because there is only one well m 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-B Data Summary--text final Feb. 5 .0 3 Wilmington, DE ASH021688 EID639920 C-8 Date Summary Report Pry Run Landfill Water Quality Groundwater 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 underlying water-beanng zones (A-Zone, B-Zone, and C-Zone) at the Dry Run Landfill. The highest concentrations o f C-8 measured in the overburden and underlying zones are found in the wells that are the closest to the toe of the landfill. The highest C-8 concentration measured in groundwater at the Dry Run Landfill is 20.9 ug/1, significantly lower that the CATT-estahlished C-8 SL of 150 ug/1. The highest concentration o f C-8 in groundwater used as drinking-water source by residences located within a one-mile radius of the landfill was 0.422 ug/1. The highest concentrations o f C-8 in groundwater used as non-drinking-water and unused sources by residences located within a one-mile radius o f the landfill was 0.54 and 0.974 ug/1, respectively. These values are also significantly lower that the C-8 h i ot 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 die Dry Run Landfill. The leachate samples have shown the highest C-8 concentrations with a maximum concentration o f 704 ug/1. It is expected that leachate from the landfill would have the highest concentration of C-8 because the source for the C-8 is likely the landfilled materials. Leachate at the Dry Run Landfill does not discharge to surface water. It is collected at the landfill and is treated at the facility. Six o f 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 stormwater from the area. The 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 o f C-8 observed at this location has been 39 ug/1, although, seven o f the 11 samples collected from this point have had C-8 concentration less than 10 ug/1. With the exception o f the leachate samples, the C-8 concentration o f 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) o f 1,360 ug/1. 6.5.2 Current Human Health and Ecological Exposure Pathways The main objective o f the Consent Order was to determine whether there has been an impact on human health and the environment as a result o f releases o f C-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 ecologica! 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-B Date Summary - text final Feb. 5 ,0 3 Wilmington. DE ) ASH02168 9 EID639921 C-B Data Summary Report Pry Run Landfill evaluated and classified as complete or incomplete. Table 6.5 summames the human health and ecological exposure pathway evaluation for the Dry Ru" J. conservative, for each complete exposure pathway, the maximum 0 8 concentration measured in the 0 8 impacted media is compared to the 0 8 SL, regardless o f media type, On-Site Human Health and Ecological Exposure Pathways Current Environmental Setting The on-site current human health and ecological exposure pathways section descnfe* the potential exposure routes for human and ecological receptors that are found attheD ry 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 o f workers in the central portion o f the landfill area during normal working ho r . The institutional controls and the daily activity discourages trespassers on the site. Direct contact with landfill materials or soils impacted by the materials m the inactive, low half of the landfill is incomplete due to the leachate collection system s geotexfile and geomembrane cover. However, direct contact with landfilled materials or soils impacted by the materials at the active, upper half o f the landfill is a complete pathway an is limited to the workers in active portions o f the landfill. Precipitation felling in the upper half o f 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 through the 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 o f feetbgs at the upper end o f the landfill. In the lower end o f the landfill, the A-Zone is exposed at the surface. However, no seeps were observed in the areas where this zone is exposed. In 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 groundwater as an exposure pathway is also incomplete. Contact with C-8 impacted surface water near the toe o f 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 m surface waterrn this area has ranged from 0.54 to 87 ug/1, less than the C-8 SL established by the CATT and significantly less that 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 3 9 ug/i( which are below the C-8 SL and are significantly lower than the C-8 ALAC, In WWK-C-B Dala Summary ~ text final Feb. 5 ,0 3 Wilmington, DE A SH 021690 1ID639922 C-8 Dato Summary Report 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 Pathw ays 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 considered to be an incomplete pathway in situations where the water source is not used. The pathway is considered-tcrbe-a complete-pathway wheirthe watersonrceisusedbut not for drinkingwater purposes although the exposure is considered to be minimal because the water is not ingested. The highest C-8 concentration in a non-drinking-water sample was 0.54 ug/1, well below the C-8 SL o f 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 o f 150 ug/1. Therefore, the pathway is complete, and exposure is considered to be limited due to the low C-8 concentrations measured. Outside o f 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 ND 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, ' Dry Run Landfill Summary Many different activities have been conducted at and around the Dry Run Landfill in order to determine whether there has been an impact on human health and the environment as a result o f releases o f C-8 to the environment from the 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 o f the data evaluated for the Dry Run Landfill, foe following observation ware made: Q The current exposure pathways are incomplete for human and ecological receptors contact with on-site leachate and groundwater. 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 o f 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 foe active landfill and when managing the leachate collected at the Dry Run Landfill, and surface water. WWK-C-B Data Summary - text final Feb. 5 ,0 3 Wilmington. DE ASH021691 IID 639923 C -8 Dato Summary Report Dry Run Landfill O Contact with surface water exiting the site that has been impacted by C-8 1$ 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 o f 150 ug/1 and lower than the C-8 ALAC of 1,360 ug/1 (Menzie-Cura & Associates, 2002). C-8 concentrations measured in seven o f the samples taken at the property boundary were less than 1 0 ug/1, indicating that while this exposure pathway is complete, exposure ts limited because o f the low concentrations of C-8 detected. 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. For the drinking and non drinking-water sources, the highest C-8 concentration measured were 0.422 and 0.54 ug/1 respectively, which are well below the C-8 SL o f 150 ug/1 and the C-8 ALAC of 1,360 ug/1 (WV DEP, 2002; Menzie-Cura & Associates, 2002). Qi Evaluation o f the C-8 results measured at the Dry Run Landfill, o f the groundwater flow direction at the landfill, and o f the one-mile radius C-8 results shows that C-8 impacted groundwater is not migrating off-site. 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 o f C-8 by air emissions from the facility cannot completely be ruled out, and m aybe the source o f C-8 for the very low concentrations measured within the Dry Run one-mile sampling area. WWK-C-B Data Summary - text final Feb. 5 .0 3 Wilmington, PE SHQ21692 EID639924 0 8 Data Summary Report References 9 7.0 REFERENCES DuPont 1990. Washington Works 1990 Preliminary Hydrogeologie Assessment. Solid Waste & Geological Engineering Department. 1992. Verification Investigation E J. DuPont de Nemours Co. Washington Works April 1992. (VoL 1). 1996. Report o f Geotechnical Investigation Dry Run Landfill, Washington Works Main Plant, Parkersburg, WV. Geotechnical Group, Civil Engineering Systems DuPont Engineering. ' 1 9 9 9 . RCRA Facility Investigation Report, DuPont Washington Works, June 30 1999, DuPont Corporate Remediation Group and URS Diamond. _ _ _ _ _ 2000, Letart Landfill Groundwater 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 Remediation Group and' URS Diamond. ______ 2002b. Compilation o fHistorical C-8 Data, DuPont Washington Works Main Plant and Landfills January 2002. DuPont Corporate Remediation Group and URS Diamond. ______2002c. Proposed Groundwater M onitoring Planfo r Washington Works Facility Plant and Landfills January 2002. DuPont Corporate Remediation Group and URS Diamond. 2002d. Email with attached map from Andrew Hartten o f DuPont to the Groundwater Investigation Steering Team 2/25/02. ______2002e. C-8 Plume Identification/Groundwater 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-8DataSummary-text (inai Feb. 5,03 Wilmington. DE ASH021693 BID639925 C-fl Date Summary Report References 2002f. January 2002 Groundwater Investigation Quality Assurance Project Plan fo r Washington Works Plant Washington, WV>January 2002, DuPont Corporate Remediation Group and URS Diamond, 2002g. May 2002 Groundwater Investigation Quality Assurance Project Plan Addendumfo r Washington Works Plant Washington, WV, January 2002. DuPont Corporate Remediation Group and URS Diamond. 2002h. Two-Mile Radius Survey and C-8 Sampling, DuPont Washington Works 'F adlity/locat Landfill, West Virginia (March-May 2002) August 2002. DuPont Corporate Remediation Group and URS Diamond. 2002L One-Mile Radius Survey and C-8 Sampling Report, Washington County, Ohio (March -June 2002) August 2002. DuPont Corporate Remediation Group and URS Diamond. 2002j. Two-Mile Radius Survey and C-8 Sampling Report, Washington County, Ohio (June - September 2002) December 2002. DuPont Corporate Remediation Group and URS Diamond. 2002h Fourth Quarter 2002 C-8 Suiface Water and Groundwater Monitoring ~Report For Washington Works Facility and Local, Letart and Dry Run Landfills Washington, WVDecember 2002. DuPont Corporate Remediation Group and URS Diamond. 20021. Ohio River Water Sampling Results, Washington Works Facility and the Letart Landfdl November 2002. DuPont Corporate Remediation Group and URS Diamond. 2002m. 3Q02 and 4Q02 Public Water Supply Results, West Virginia and Ohio, DuPont Washington Works, Washington ^ N o v e m b e r 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 D ry Run Landfills Washington, WVJanuary 2003. DuPont Corporate Remediation Group and URS Diamond. Exygen. 2002. Personal Communication between John Flaherty, Operations Manager, Bxygen Research, Inc. and Michael D. Aucoin, Project Chemist, URS Diamond. WWK-C-8 Data Summary - text final Feb. 5 .0 3 Wilmington, OE ASH21694 1ID63926 C-B Date Summary Report References Menzie-Cura & Associates, Inc. 2002. Final Report, C8 Assessment o f Toxicity team (CATT) Report Addendum Aquatic Life Advisory Concentrationfo r C8. Potesta & Associates, Inc. 1999. Monitoring Wells M W -l, MW-1A, MWM, MW-4A, MW-6, MW-10, MW-IO Abandonment Report, Dry Run Landfill, DuPont Washington Works. March 1999. Simard, C. M. 1989. Geological History o fthe Lower Terraces and Floodplains o fthe Upper Ohio River Valley, Open File Report, West "Virginia Geological Survey, I60p, Schultz, R.A. 1984. Groundwater Hydrology o fthe Minor Tributary Basins o f the Ohio River, West Virginia Tetra Tech Richardson. 1990. Monitoring Well Installation Program at Letart Landfill Summary Report, August 1990. USEPA. 1994. Region t i l Modifications to NationalFunctional Guidelinesfo r Organic Data Review. WVDEP. 2002. Final Ammonium Perfluorooctanonate (C8) Assessment o f Toxicity Team (CATT) Report. August 2002. West Virginia Department o f Environmental Protection W W K-OB Data Summary - text final Feb. 5 .0 3 Wilmington, DE ASK021695 EID639927 TABLES ASH021696 to a*4 M. Table 3,0 Summary of Off-site Sampling Program (C-8 Sampling) DuPont Washington Works Facility and Local Landfill Washington, WV .... .....---- r ,ll iI.'.T'i.iI., .'l.l'U.J. 1 RESIDENTIAL SAMPLING FOR 1-MILE RADIUS : Number of homes contacted(1) 311 x Number of homes surveyed<1) 269 Number of wells identifiedt2) 51 jn Number of wells sampled<2) 34 J Number of wells sampled that are used for drinking water 6 # Number of cisterns identified l2) 17 t0 'S Number of cisterns sampled(2) 6 .0 Number of cisterns sampled that are used for drinking water 0 Number of springs identified <2) 6 Esta Qc. Number of sprinas sampled<2) 4 CO Number of springs sampled that are used for drinking water 0 (0 M . Tota! number of samples 44 Total number of collected samples used for drinking water e Note: R eid duplicates not considered In sam ple count. During this investigation, hom eow ners/residents identified within the sam pling radius w ere contacted to determ ine residential w ater u sag e. Up to two contacts w ere attem pted at each residence. A fter to e seco n d contact attem pt, a voluntary survey w as left a t toe residence. B ecause not all hom eow ners/residences responded to to e survey, th e num ber of resid en ces surveyed is le s s than to e num ber of hom es contacted, 12)Som e w ater so u rces (e.g. w ells, cisterns, springs) identified during the survey w ere not sam pled. In m any c a se s , sam pling of th ese w ater sources w as refused by the hom eow ners/residents. In o th er c a se s, th e w ater sources w ere either not accessible or dam aged. As a co n seq u en ce, th e num ber of w ater sources sam pled w as less than the num ber of w ater so u rces identified. 2 /4 /20 0 3 1 of1 T ab 3.0 C onsent O rder T&F.xIs ASH021697 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 S em o le ID S an to le D ate OS-AHEARTR 12/19/2001 ! OS-BALSEYAR 12/21/2001 o s -balS ey a r 4/11/2002 : OS-CHRISTMANS .... 12/21/2001 OS-CHRISTMANS 4/11/2002 ------ ' " O ^ S M T O T " 2/5/2002 OS-VINCENTS 12/17/2001 ' OS-VINC&TS ' 4/11/2002 OS-WILCOXA 1/26/2002 0&.WILOXA "`W im m OS-ANSLEYB " 1/26/2002 OSBEBEEB 1/15/2002 SBLANKENSHIPR 2/21/2002 - o s -b u r c HAr d a 1/9/2002 OS-BUHDbl IE P - 1/1/202 OSCNM 1/27/2002 OS-CAYTONW 1/25/2002 OS-COCHRANG 1/25/2002 " OS-CORBITTG ' 1/23/2Q2 OS^OW ANJW 3/27/2002 OS-CREELK1 ....... 1/27/2Q2 OS-CREEL.K2 ......1/27/2002 " OS-DVISJ ` 1/9/2002 .... OSAKNE 1/9/2002 OS-FIKER 1/23/2002 OS-FURBEC " "1/23)2002 OS-HENDRICKSR 1/25/202 O SLA K EW A Stfci " 1/14/2002 s-LA kw sW ca 1/15/2002 OS-LAWSONDH 1/8/2002 OS-MIUJERJ .... 1/14/2002 OS-MILLSS 12717/2001 OS-NEWHOUSES ~"/27/2002 OS-PARSONS D TM 2 1 02 OS-RICHARDSV ^ 1 ^ 1 7 0 1 o s -r id d Le d i 2/12/2002 OS-WAYBRIGHTO 1/15/2002 o s -w h it a K r k 1/10/2002 C -aug/l . 1.74 S3 0.328 0.526 1.33 1 l.f 1.72 1.74 1.83 3.2 0.715 0.41 1.7 2.93 3.63 1.3 0.945 14.3 2.7 7.47 3.36 0.569 0.32 5.07 1.72 0.347 0.867 9.56 3.94 0.932 0.304 3.44 , 2g.3~7 0.252 . 2.3 OS-LAWSONDH2 1 /1 0 2 0 0 2 ' OS-RIDDLED2 2/12/2002 ~ OS-SHOCKEYG m iim z _ OS-rALLHAMfcH .. " 1/28/2002 10.9 2.8 ^1.33 W ater U se* Drinking W ater TSrinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater U nused U nused U nused ' U nused U nused U nused U nused U nused U nused U nused U nused U nused U nused MfeC. U nused W ater CatBe U nused U nused M isc. U nused U nused Misc. U nu sed ..... U nused M isc. U nused U nused U nused U nused U nused U nused W aTdrCattle Sam D leT voe ... '' Well W ell ............ Well ~W 5i W ell Well Well W ell ..................W l -- v ia l W ell W ell W ell W ell W ell Well Weil Well ' ' ' Well W ell Well W ell W ell W ell W ell W ell W ell W ell W ell Well W ell W ell " Well ~ HM W ell W ell W ell W ell Spring Spring SorSig Spring 1/29/2003 4:25 PM 1 of 2 Tab 3,1 Consent Order T&Fjds A SH 021698 EID639930 Table 3,1 Summary of C-8 Analytical Results In Groundwater and Surface Water (ug/t) Washington Works Facility and Local Landfill (Off-site Wells, Springs, and Cisterns - One Mile Radius) Washington, WV S am te ID S am p le D ate C -8ua/1 y u ja g g g u u I'I . ~ W ater U se * .... Sam ple Type OS-ALKlRF 1727/2002 d & 'o illN S C 12718/2001 S-P RtRBL 12/19/2001 ' o s -s m it h MM 12717/2001 OS-THOMPSONB 12/17/2001 g & w ffiK rc ig c c 12/17/2001 3.1 : ;j-- 0.681 2 .4 8 TM ~T32' U nused M ise, M ise. M ise. W ater C attle '`" ''"'HraScTM" TM C istern C istern C istern C istern C istern C istern * Drinking W ater (highlighted In boW blue) Inacales human consumption. Non-drinking W ater use Include livestock watering, gardening and any other non-human consumption water uses. Mise. Miscellaneous water use la not used ter drinking. Date highlighted in yellow aro resute ter water sources located within the one-mile radius teat were resampled during the two-mlla radius campling event 1/29/2003 4:25 PM 2d 2 Tab 3.1 Consent Order TF.xIs A SH 021699 E ID 633931 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 SAMPLINe FOR THE 2-MILE RADIUS S Number of homes contacted(1) $67 I Number of homes surveyedt1) 109 Number of wells identified<2) 98 M Number of wells in sampled(2) 52 Number of wells sampled that are used for drinking water 17 Number of cisterns identified(2) 17 t 3 Number of.cisterns sampledt2) 8 o Number of cisterns sampled that are used for drinking water 0 Number of sorinas Identified(2> 7` e Number of sprinas sampled(2) 5 Number of springs sampled that are used for drinking water 1 !Q. Total number of samples 65 <0 Total number of collected samples used for drinking water 18 N ote: R eid duplicates not considered In sam ple count. <1>During thl3 Investigation, hom eow ners/residents Identified within th e sam pling radius w ere contacted to determ ine residential w ater usage. Up to two contacts w ere attem pted a t each residence. A fter th e secon d contact attem pt, a voluntary survey w as left a t th e residence. B ecause no t all hom eow ners/resldences to the survey, th e num ber of residences surveyed is less than th e num ber of hom es contacted. 12)S om e w ater so u rces {e.g. w elts, cisterns, springs) identified during the survey w ere not sam pled. In m any c a se s, sam pling of th ese w ater sources w as refused by the hom eow ners/residents. In o th er c a se s, th e w ater so u rces w ere either not accessib le or dam aged. A s a consequence, the num ber of water sources sam pled Was le ss than th e num ber o f w ater so u rces identified. 2/4/2003 1 of 1 Tab 3.2 Consent Order T&F-Xls ASH02170O 110639032 Table 3.3 Summary of 0 8 Analytical Resulta In Groundwater and Surface Water (Off-site Wells, Springs, and Cisterns) Washington Works Facility and Local Landfill Two-mile Radius Washington, WV J I d 2-M ile S am p le ID O S-H A M IU O N F 0S -U N G E R A C 1 O S-ST E PH E N SD S 0S-5TEPH EN SEE O S-M C M A H A N G i O S-B A K iR iR O S-JA M ESO N RD OS-COLVINRL OS-FOUTTBL -- OS-NAYJL OS-BOSOEG OS-HESSQK O S-N EW BERRY PC OS-MILLSL OS-SMITHPL GS-PHILIPSAE 0S-C 0LEM A N C 1 OS-JOHNSONL1 OS-W iATHERHOLTU Q 3-0A R N E SA L OS-RHOADESRW OS-W IGAU S-Y Q ST J OS-GOLDSMITHML B OS-SAMSCW OS-SACCHID OS-JOHNSONL2 QS-UNGERC2 OS-ARNOLDWC OS-BARKERC : OS-WOLFEDJ ' ........ OS-WYTTVE OS-DOTSONH OS-HAMMONDE OS-CAMPBELLG OS-SARTORL O S-GLA SSe O S-M A TH EW SJR O S -R E E D E R H J OS-MILLSS OS-TUCKERCM OS-TALLMANE O S-U FE M OS-MOREHEADV OS-NORMANE D ate 3/14/2002 3/14/2002 3/14/2002 3/14/2002 3/15/2002 3/18/2002 mmm 3/19/2002 3/19/2002 3/19/2002 3/28/2002 3/28/2002 ' 4/5/2002 4/18/202 4/24/2002 4/25/2002 6/4/2002 3/14/2002 3/20/2002 4/3/2002 4/29/2002 5/8/2002 5/14/2002 5/20/2002 5/20/2002 sfem m 3/14/2002 3/14/202 4/8/2002 4/6/2002 4/8 002 4/12/2002 5/0/2002 mm2 5/ 10/2002 5/13/2002 5/13/2002 5/14/2002 5/14/2002 5/14/2002 5/21/2002 5/21/2002 5/22/2002 5/23/2002 5/29/2002 5/29/2002 C -B utj/L 0.737 ND (<0.010) 0.625 0.229 ND (<0.010) NQ {<0.0501 ND (<0.010) 0.242 .B99 0.465 NQ {<0050) NQ {<0.050) 0.386 N D (<0.010) ND (<0.010) 0.73 ND (<0.010) ND (<0,010) 0.078 1,3 1.56 0 .6 2 5 0.081 0.874 1,2 ND (<.) 1.08 1.36 2 0.706 .17 1.19 0.164 ND (0.010) 0 .0 7 4 0.091 0 .9 2 7 0.425 0.781 1.17 1.57 0.095 0.325 0.257 1.19 0,692 - W ater Use* S am ple Type Drinkinn W ater W ell Drinking W ater Well Drinkinn W ater W ell Drinkinn W ater W ell Drinking W ater Well Drinking W ater Well Drinking W ater W eil Drinking W ater W eil Drinking W ater Well Drinking W ater W ell Drinking W ater Well Drinking W ater Well Drinking W ater W ell Drinking W ater W ell Drinking W ater Weil Drinking W ater W ell Drinking W ater w ell Non-drinking W ater W ell Non-drinking W ater W ell Non-drinking W ater W ell Non-drinking W ater Well Non-drinking W ater W ell Non-drinking W ater Non-drinking W ater Well W eii Non-drinking W ater W ell Non-drinking W ater Wei) U nused W ell U nused W ell U nused W ell U nused Wei! U nused U nused -- Wyeljl Unused * * _ U nused W- gel.l U nused W ell U nused W ell U nused U nused W ell W ell U nused w ell U nused W ell U nused W eil U nused W ell Llnused W eil U nused Well U nused Wefl U nused W ell 1 /3 0 /2 0 0 3 1 Of 2 Tab 3.3 C onsent O rder T&F.xls ASB21701 1D639933 Table 3,3 Summary of 0 8 Analytical Results In Groundwater and Surface Water (Off-site Wells, Springs, and Cisterns) Washington Works Facility and Local Landfill Two-mile Radius Washington, WV 9Mite S am p le ID D ate C-B ug/L O^BIRAM B 5/29/2002 0560 OS-VAUGHNDI 5/30/2002 ND (<0.010) OS-MtTCHELLL OS-SMITHLK 5/30/2002 5/31/2002 1.20 0 .0 9 2 OS-WRIGHTW 6/3/2002 1.07 03-R IG H A R D S C 6/3/2002 1,52 OS-STUTTLERLR OS-BLOOMERQG 3/27/2002 3/21/2062 " 1.8 0 .8 5 7 " O S-B U R TO N bi 4/16/2002 .... 0 .8 2 3 QS-RiTTENHQUSE .... 4/16/2002 OS-ARTHURRS 3/20/2002 0 .8 9 8 2 .3 2 OS-WALTERSMM 3/22/2002 1.39 OS-WILLISJL 4/24/2002 0 .7 7 2 OS-HERTZTL 4/25/2002 1.67 O S -B L U iR i 4/16/2002 0 .4 4 7 OS-EDDYMM 4/24/2002 2.27 OS-EDDYMM2 4/24/2002 1.84 " ' OS-PUGHJ/ 5/14/2002 NQ (<0.050) OS-NUTTERK 5/22/2002 0.174 W ater Use* Sam oieT vpe U nused W eil U nused . wen U nused U nused W eil W ell U nused w en U nused W ell Drinking W ater Sprint Non-drinkina W ater S p rin t Non-drinking W ater Sprint Non-drinkina W ater S p rin t U nused S p rin t Non-drinkina W ater Non-drinking W ater Non-drinking W ater U nused C istern C istern C istern C istern Unused . Q tatefr U nused C istern U nused C istern Unusedr. ...1- - C&tie-i1'f1iri * Drinking W ater (highlighted in bold blue) indicates hum an consum ption. Non-drinking W ater u se s include livestock w atering, gardening and any other non-hum an consum ption w ater u se s. ,, , ,, ND - Not D etected a t or above th e limit of detection (LOD). T he listed 1 0 D is approxim ate and varies by instrum ent and over tim e. NQ = Not Q uantifiable. D etected a t a concentration above th e 10D and below the limit of quantification (LQQ). 1 /3 0 /2 0 0 3 2 of 2 T ab 3.3 C onsent O rder T&F.xls A SH 021702 IID63S934 Table 3,4 Summary of Off-site Sampling Program (C-8 Sampling) Ohio One-mile Radius Residential Sampling DuPont Washington Works RESIDENTIAL SAMPLING FOR OHIO 1-MILE RADIUS i X Number of homes contacted t1> -- *3--61-- " Number of homes surveyed( > 150 Number of wells identified 7 8 ... _ U5> Number of wells sampled{> 47 Number of wells sampled that are used for drinking water 17 . Number of cisterns identified(2) e (2) &ift Number of cisterns sampled that are used for drinking water t> Number of cisterns sampled that are used for drinking water 16 5 0 m Number of sprinas identified(2) 15 it & Number of sprinas sampledt2) 15 Number of springs sampled that are used for drinking water 1 S<3D Poo 1 s Total number of samples 68 HL i to Total number of collected samples used for drinking water 18 Note: Field duplicates not considered in sam ple count. TODuring this investigation, hom eow ners/residents identified within th e sam pling rad us w ere contacted to determ ine residential w ater u sag e. Up to tw o contacts w ere attem pted at each residence. Afterth e second contact attem pt, a w as left a t the residence. B ecause not all hom eow ners/residences to th esu n rey . th e num ber of resid en ces surveyed is to ss th an the num ber of hom es contacted. ra so m e w ater so u rces (e.g. w ells, cisterns, springs) Identified during the survey w ere not sam pled. In m any c a se s, sam pling of th e se w ater so u rces w as refused by the hom eow ners/residents. In other c a se s, th e w ater so u rces w ere either not accessible or dam aged. As a consequence, th e num ber of w ater so u rces sam ples w as le ss than th e num ber of w ater so u rces identified. 2/4/2003 Tab 3.4 C onsent O rder T&F.xIs SH021703 EID639935 Table 3.5 Summary of C-8 Analytical Results in Groundwater and Surface Water Ohio One-mile Radius Residential Sampling 1 /3 0 /2 0 0 3 1 of2 Tab 3.5 C onsent O rder T&F.xIs A SH 021704 EID639936 Table 3.5 Summary of C-8 Analytical Results in Groundwater and Surface Water Ohio One-mile Radius Residential Sampling 1-MHa S am ple ID OS-THOMPSONAM OS-ARBAUGHJ OB-YATESL O S -SPIG E R R F ... '.........OS-STAHLFR2 OS-STEPHANML2 OS-RAUCH SPQ1 RAUCH SPG 2 OS-RAUCH SPQ 3 .. OS-RAUCH SPG 4 OS-FtAUCH SPG 5 OS-WATSON MP2 OS-WATSON MP3 OS-SWEARINGENW S-STAHLPR1 S-CASTB1 OS-CASTOB1-2 ... OS-CSTOB2 (dup) ` OS-CSTQB3 .....o s -s t e p h a n Ml OS-PARLEYED OS-WATSON MP4 "" " ........."'OS-BEECHJB OS-BRICKMANCH : OS-STEPHANML3 S am p le D ate 5/16/2002 5/23/2002 5/24/2002 mmm 4/6/2002 m im i 4/11/2002 4/11/2002 4/11/2002 4/11/2002 4/11/2002 4/18/2002 mmm 4/22/2002 4/8/2002 6/7/2002 6/7/2002 6/7/2002 6/7/2002 4/9/2002 4/15/2002 4/16/2002 5/29/2002 6/4/2002 4/9/202 C -8yg/L 4.22 1.02 328 129 5.72 8.88 3.58 4,67 4 4.97 5.78 18.1 23,6 8.55 4,97 3.81 4 .3 2.98 5.835.41 1.28 7.33 2.85 0 .7 4 8 2.52 W ater Use* U nused U nused U nused Drinking W ater Nort-drinWng W ater Non-drinking W ater N on-drinkingW ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater N on-drinkingW ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater Non-drinking W ater U nused Non-drinking W ater Noh-drinklng W ater Sam ple Type W ell W ell Well . . . Spring Spring S p rin t Sprint Sprint Spring Spring Spring Spring Spring Spring Spring ............. - sp iio a Sprfrig Soring Spring C istern C istern C istern C istern C istern POOL * Drinking W ater (highlighted in bold blue) indicates hum an consum ption. Non-drinking W ater u ses Include livestock w atering, gardening and any other non-hum an consum ption w ater u see, ND = Not D etected a t or above th e limit of detection (LOD). T he listed LOD is approxim ate and v aries by instrum ent and over tim e. NO Not Q uantifiable. D etected a t a concentration above th e LOD and below the limit of quantification (IO Q ), 1 /3 0 /2 0 0 3 2 of 2 T ab 3.5 C onsent O rder T&F.xis SH021705 EID639937 Table 3,6 Summary of Off-site Sampling Program (C-8 Sampling) Ohio Two-mile Radius Residential Sampling DuPont Washington Works RfcjNTAl SAMPUNG FOR OHIO 2-WliL RADIUS % Number of homes contactedt1) 1131 X Number of homes surveyed11 733 Number of wells identified w 123 J2 Number of wells in survey sampledlZ) 58 Number of wells sampled that are used for drinking water Number of cisterns identified.(2> Number of cisterns sampled{2) o Number of cisterns sampled that are used for drinking water to k 1 I <3 Number of springs identified B) Number of sprinas sampled Number of serines sampled that are used for drinking water Total number of samples Total number of collected samples used for drinking water 49 7 3 0 3 1 0 62 49 N ote: Field duplicates not considered in sam ple c o u n t 01 During this investigation, hom eow ners/residents Identified within th e sam pling radius w ere contacted to determ ine residential w ater u sa g e . Up to two contacts w ere attem pted a t each residence. A fter th e second contact attem pt, a voluntary survey w as left a t th e residence. B ecau se not all hom eow ners/residences to th e survey, th e num ber of residences surveyed Is le ss than th e num ber of hom es contacted. ta so m e w ater sources (e.g. w ells, cisterns, springs) Identified during th e survey w ere not sam pled. In m any c ases, sam pling of th ese w ater so u rces w as refused by the hom eow ners/residents. In o th er c a se s, the w ater so u rces w ere either not accessible or dam aged. A s a co nsequence, th e num ber of w ater so urces sam pled w as less than th e num ber of w ater sou rces identified. 2 /4 /2 0 0 3 lofi Tab 3.6 C onsent O rder T&F.xls ASH021706 D 639938 Table 3J Summary of C-8 Analytical Results Zones A, B and C Ohio Two-Mile Radius C-8 Residential Sampling 1 /3 0 /2 0 0 3 1of 2 Tab 3,7 C onsent O rder T&F.Xls ASH021707 EID639939 Table 3.7 4 Summary of C-8 Analytical Results Zones A, B and 0 Ohio Two-Wile Radius C-8 Residential Sampling Q (cont.) Sam ple ID Sam ple Date OS-KingOD 8/16/2002 .. OS-KlnaCD-2 (DUP) mmm "" OS-KirkWE 8/14/2002 ............ OS-KnoxQT 8/16/2002 " OS-MillironMP 8/21/2002 OS-MoodyDA 8/20/2002 .................. OS-ShivelyJH " OS-SouthaltSA 8/22/2002 8/22/2002 ....... o s* S p ad erJD 8/16/2002 O S-St. Clair 9/25/2002 ..... OS*StimpertFfe 8/21/2002 :" OS-TaittW J 9/9/2002 O S -T ransport 0/16/2002 ' OS-W ebbD 9/25/2002 OS-W heatonCA 8/24/2002 S-W heatoriDC -- 8/21/2002 C-8 ug/L NO (<0.01) ND (<0,01) ND (<0.01) ND (<0.01) ND (<0.01) ND 0.01: NO {<0.05' 0.085 N D M J.O T NQ (<0,05 ND (<0.01 5.810 ND (<0.01 0.128 NC5 {<0.05 0.087 W ater Use* Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Sam ple Type W ell W ell W ejl W ell W e|i W ell W ell W ell "w eS W eil W ell W ell W eil W ell Well W ell *-Drinking W ater (highlighted in bold blue) indicates hum an consum ption. Non-drinking W ater u se s include livestock w atering, gardening and any other non-hum an consum ption w ater u ses. ND = Not D etected a t o r above th e limit of detection (LOD). T he listed LOU \ is approxim ate and varies by instrum ent and over tim e. NQ = Not Q uantifiable. D etected at a concentration above the LQD and below the limit of quantification (LOQ). 1/30/2003 2 of 2 T ab 3,7 C onsent O rder T&F.xIs ASH021708 EID639940 Tabie 3.8 Monitoring W e l Construction and Groundwater Elevation Data DuPortt Washington Works Facility Washington, WV New W all 10 Old W ell 10 M easuring P o in t E levation (ft) W elt D iam eter (in c h e s) S lo t Size (Incites) lig B SE il)l*0tm tt3rl{iK AE11-MW01 AJQ6-MW02 AM07-PW01 AO08-PW01 jAX13-PW01 D08-MW01 TW-74 j 336 331 335 TW-M5 -1 S 8 E13-MW01 j JC16-PW01 L04-PW01 TW -75 L4(354) GALLERY 628.94 6929 2 0.010 635.55 j 63426 128 95 2 18 0.010 63221 95 18 630.69 90 18 6 0 0 .6 7 4 625.47 76.8 2 0 .0 1 0 62324 18 589.75 S creen L ength (ft) E levation o f S creen interval (ft) 10 669.65 559.65 * 15 20 52265 507.55 ..U " 5582853826 January-02 567.02 -- * F eb ru ary -0 2 M arch-02 A pril-02 M ay-02 556.02 56420 565.93 566.54 -- -- -- -- * * * A ugust-02 O ctober-02 567.61 568.52 -- 569.55 * * G roundw ater elevations not m easured in production w eils. **Well w as dry 20 557.91 537.91 * * * * * * *- 13 10 NA 5 5 3 .6 9 540.69 -- * w * * * 558.67 - 'S**.' ' "'v '" 't.'.ST':f .. 548.67 ^v - ^ r 562.73 562.69 562.09 562.51 562.71 564.55 56424 5 6 1 .2 9 5 6 1 .1 2 562.04 560.59 5 6 0 .7 6 56223 561.91 . * * * -------------- ; * a- * * e ASH021709 10/2003 .t 1 of 2 I II IT Table 3,8 Monitoring Well Construction and Groundwater Elevation Data DuPont Washington Works Facility Washington, WV M m eam ok t ,h. 1 lidaw W a i f in fniH m oil tn [.M easuring P o in t p e ll D iam eter Slot NG4-MW03 N13-MW01 P04-MW02 P08-MWQ1 Q04-MWG2 R04-MW02 R on's MW-5 TW-83 ^on's MW-4 RorfsM W -1 TW-85 V O 5PW 01 RANNEY Y14-MW01 TW -90 Y14-MWOT2' 595.44 6 8 .5 2 10 15 625.87 59.95 2 0.010 5 27.81 2 0.010 1:0 625,29 8 8 .3 2 5 9 8 .7 6 39.64 2 5 10 594.92 2 7 .6 4 2 0.010 10 632.00 92 NA 1 6 4 2 .2 5 90 64342 131.59 2 0 .0 1 0 --------2s ------0 .0 1 0 10 15 B evation o f S creen Interval liftl 5 2 1 .9 4 - 570.92 - 505.94 56552 5 7 4 .5 8 584.58 5 6 5 .9 9 560,99 5 6 9 .1 2 55942 5 7 7 ,2 8 557.28 542.00 541.00 562.25 552.25 526.53 511.53 ! ' '. January-02 572.35 F e b ru a ry -0 2 M arch-02 559.92 **- 571.91 573.35 L rW M r 573.13 p a y -0 2 574.32 A ugust-02 572,69 |o cto b ar-0 2 567.82 I " 1 572.11 G roundw ater elevations not m easured In production wells. `Weil w as dry 560.10 ** -** Mr 562.09 560.88 560.05 559.45 560.40 559.77 563.77 563.06 576,61 576.39 577.36 576.97 577.10 575.28 574.98 - 562.76 562.15 * 5613 * 561.34 * 561.67 * 563.05 * 562.89 561.75 I 1/3W2Q03 2 o f2 I1 I T ab 3.8 C onsent O rder T&F.xte I II ASH0217XO 1/29/2003 Table 3.9 Summary of Analytical Resulto: 0 8 in Groundwater DuPont Washington Works Facility Washington, WV " S a fo b la AB11-MWM .AJ06-MW02 AM7-PW01 A 008-PW 01 AX13-PW01 ..^ . D ate 10/16/2002 9/4/2002 5/23/2002 4/29/2002 3/26/2002 2/22/2002 1/28/2002 2/2/1999 11/10/1998 . 10/16/2002 10/22/2002 8/26/2002 5/17/2002 4/16/2002 3/21/2002 2/14/2002 1/22/2002 11/20/2000 8/16/2000 5/12/1999 2/3/1999 11/18/1998 6/19/1998 6/2/1997 4/2/1996 10/22/2002 8/26/2002 5/17/2002 4/16/2002 3/21/2002 .... 2/14/2002 1/22/2002 11/20/2000 11/20/00 (dup) 8/15/2000 5/12/1999 6/19/1998 6/2/1997 4/2/1996 10/22/2002 8/26/2002 5/17/2002 4/16/2002 3/21/2002 2/14/2002 e8 tu(j/n 1.74 1.92 1.25 1.22 2.82 1.45 1.20 . 0.69 L 0.41 0,133 0.269 0.335 0.247 0.150 0.171 0.129 0.131 0.24 0.071 J 0.578 0.082 B 1.9 L 0,4 0.79 0.48 0.415 0.42 0.499 0.497 0.568 0.439 0.355 0.4 0.26 0.167 0,307 1 0.55 0.52 0.721 0.834 0.911 1.42 1.22 1.03 -- ... _ .. ... ... .... ......... ...... . .......... .. .............. . ........... ..... _... ...... 1 of4 Tab 3 9 C onsent Order T&F.xIs ASH021711 EXD639943 Table 3,9 Summary of Analytical Results: C-B In Groundwater DuPont Washington Works Facility Washington, WV Sam ple D08-MW01 E13-MW01 K16-PW1 L04-PW01 N04-MW01 N4-MW03 D ate 10/16/2002 9/4/2002 5/23/2002 4/29/2002 3/26/2002 2/22/2002 1/28/2002 10/18/2002 9/4/2002 5/23/2002 4/29/2002 3/28/2002 2/22/2002 1/28/2002 5/12/1999 2/2/1999 11/11/1998 10/22/2002 8/26/2002 5/17/2002 4/16/2002 3/21/2002 2/14/2002 1/22/2002 11/20/2000 2/9/1999 11/18/1998 10/25/2002 8/13/2002 .......5/21/2002 4/18/2002 3/21/2002 2/7/2002 1/15/2002 7/11/2001 4/11/2001 11/20/2000 2/7/1999 11/18/1998 11/10/98 (dup) .. ....... 1/28/2002 10/16/2002 C*8 fun/ll 0.128 0.117 0.551 0.424 0.262 1.27 0.582 3.43 2.39 2.47 2.44 1.62 2.32 2.11 0.882 0 .5 9 1 2 16.2 9,71 12.4 13.2 172 12 103 7.5 18.2 0.48 L 14.3 3.06 16.1 16,1 40.9 23.5 30.9 0.202 3.99 13.8 5.89 7.9 J 33 J 689 21.2 _ ... ... -- ..- I ..... ...J .... .... ....... ... 1/29/2003 2 of 4 Tab 3.9 Consent Order T&FJfls ASH021712 SID639944 I I I 1/29/2003 Table 3,9 Summary of Analytical Results: G-8 in Groundwater DuPont Washington Works Facility Washington, WV Sam olo N13-MW01 * - P04-MW2 P08-MW01 Q04-MW02 R4-MW02 D ate G-8 fun/l> 10/16/2002 Drv-no sam ple 9/4/2002 Dry-no sam ple 5/23/2002 Dry-no sam ple 4/29/2002 3/28/2002 Drv-no sam ple Dry-no sam ple 2/25/2002 ,, 57.8 2/2/1999 29.BL 11/11/1998 <0.1 10/16/2002 46600 10/16/02 (dup) 48300 9/4/2002 34400 5/23/2002 42400 4/29/2002 36500 . 3/26/2002 32300 2/25/2002 26800 1/28/2002 23600 1/25/2001 12600 2/6/1999 13600 ..... 11/12/1998 8300 10/16/2002 ' ...... 120 .... 9/4/2002 Drv-no sam ple 5/23/2002 4/29/2002 3/26/2002 Drv-no sam ple Dry-no sample Pump problems-no sam ple _ 2/25/2002 20.7 2/4/1999 43.4 11/13/1998 36 10/16/2002 7720 9/4/2002 32.2 5/23/2002 1480 4/29/2002 1210 3/26/2002 2070 212512m 1590 1/28/2002 1480 2/4/1999 994 11/13/1998 660 10/16/2002 84100. 9/4/2002 66500 5/23/2002 68100 4/29/2002 56300 3/26/2002 54400 212512m 43600 - 1/28/2002 47000 1/25/2001 13800 2/6/1999 9420 11/12/1990 ' 1300 3 of 4 Tab 3.9 C onsent Order T& F.xIs A S H 02713 1 ID 6 3 9 9 4 5 Table 3.9 Summary of Analytical Results; C'B in Groundwater DuPont Washington Works Facility Washington, WV S n to le VO5-PW01 Y14-MW01 Y14-MW02 W est Well Field (1) D ate 10/25/2002 8/13/2002 5/21/2002 4/18/2002 3/21/2002 2/T/2002 1/15/2002 7/11/2001 4/11/2001 11/20/2000 2/7/1999 2/7/99 (dup) '1 1 /1 8 /1 9 9 8 10/16/2002 9/4/2002 5/23/2002 4/29/2002 3/28/2002 2/22/2002 1/28/2002 2/2/1999 11/10/1998 ... 10/16/2002 .... 10/25/2002 8/13/2002 5/21/2002 4/16/2002 3/21/2002 2/7/2002 /15/2002 7/11/2001 4/11/2001 " O'S tugfl) 51.2 34.8 35.8 37.8 40.9 25.1 29 11.4 5.48 13.7 124 3.95 0.66 L 18.2 18.4 16.3 13.9 15,5 10.9 12.7 4 .9 5 1 12 N Q ^0 .0 5 ) 10.3 6.41 7.09 6.69 7.72 5.77 6.52 2.31 1.58 1 I .. .... ..... ........ _J j = estim ated value (below laboratory quantification lim it) L s possible low bias result (relative to QA/QC) B= com pound detected In QC blank (sjote: A nalytical method changed as o f Novem ber 2001 (see Section 2.0 o f DuPont (2003b) fo r details). . 1/29/2003 4 of 4 T a b 3,9 C o n se n t O rd e r T& F.xts ASH02173.4 EXD639946 Table 3.10 Summary of Analytical Results: C-8 In Surface Water DuPont Washington Works Facility Washington, WV ' - Sainble .... OUTLET 001 o u t f a l L 002 OUTLET 003 . Data 11/13/2002 10/10/2002 9/24/2002 8/27/2002 7/23/2002 6/28/2002 5/20/2002 4/16/2002 3/10/2002 2/5/2002 1/17/2002 12/20/2001 11/13/2002 ... 11/13/02 (dup) 10/18/2002 9/24/2002 8/27/2002 8/27/02 (dup) 7/23/2002 6/25/2002 6/25/02 (dup) 5/20/2002 4/16/2002 " 3/19/2002 2/5/2002 1/17/2002 12/20/2001 11/26/01 10/25/2001 ...... 9/19/2001 7/11/2001 6/14/2001 5/31/2001 4/11/2001 3/21/2001 2/14/2001 11/13/2002 10/18/2002 9/24/2002 8/27/2002 7/23/2002 6/25/2002 5/20/2002 4/16/2002 3/19/2002 . 3/19/02 (dup) 2/5/2002 C-8 (ug/l) . .... J 17.0 10.5 2.15 2.94 8-63 17.9 ........_ ,, 22.4 ....... 19.7 21.4 ........ 9.43 10.9 3.72 4.76 6.28 3.49 2 .1 4 2.56 2,51 229 3.86 3.81 . 4.13 2.45 5.85 4.66 423 ....... _ 1.98 4.84 2.6 0.118 0.558 6.594 0.436 1.5 8.54 1.74 --1 1,24 0 .8 7 0217 0268 0291 0.175 0.503 2 .7 6 2.91 2.81 1.33 ...... ... 1/29/2003 1 of 3 Tab 3.10 C onsent O rd er T& F.xls A SH 0217X 5 UD639947 Table 3,10 Summary of Analytical Results: C-8 in Surface Water DuPont Washington Works Facility W ashington, WV a : 1/29/2003 2 of 3 Tab 3.10 C onsnt O rd er T&F.xIs A SH 021716 H D 639948 Table 3.10 Summary of Analytical Results: C-8 in Surface Water D u P o n t Washington Works Facility Washington, WV I' SaitmlB OUTLET 105 (Coni) ___ r"> D ata___ _ B/25/2002 5/20/2002 5/20/02 (dup) 4/16/2002 3/19/2002 2/5/2002 1/17/2002 12/20/2001 C-8 iuo/D 3*00 . 8.27 5.18 15.9 13.2 14.8 7.53 9.78 I SorHnn 9 fl fit DllPOilt 12003b) tor d la is ). 1/29/2003 3 of 3 Tab 3.1 0 C onsent O rd er TSF.xte A SH 021717 ED630949 i Table 3 . Ohio River Water Sampang C-8 Results DuPont Washington Worte Facility and Leiart Landfill ASH021718 H aO 1 /2 * 2 0 0 3 lI A S H 02 1 79 EI063995 Ta 3.11 ConsentOuterTSFjtis Table 3.12 Outfall 005 C-8 concentration (ug/l) DuPont Washington Works . ..S am p le ID 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 WWK-Z- OUTFALL 005 Date C-8 Ufl/L 6/24/2002 26.7 6/25/2002 17.9 6/26/2002 47.7 6/27/2002 79.3 7/1/2002 13.6 7/10/2002 37.8 7/11/2002 239.0 7/12/2002 12.5 10/16/2002 141.0 10/17/2002 18.0 1/29/2003 .1 of 1 Tab 3.1 2 Consent O rder T&F.xIs A SH 021720 E ID 6 3 9 9 5 2 Remote User Remote User Job 183 07/16/04 10:22 AM i :: :: :: :: : :: ::::: : :::: :: Tabi 3.13 Summary of C-8 IrGroundwater Public Water Supplies, West Virginia and Ohio Dupont Washington Works Facility, Washington WV Location ~ '~ 1 Belpi, OH ~ Blennerttasseit Island. VW Linio HocWng, OH Sample ID PPSOPT PP5DAT PPSOAT PPSDRANY1 PPSDRANY1 PPSDRANY1 PPSDRANY2 PPSDRAKY3 PPSDRANY4 PPSDRAMY5 BELPSDA BELPSDAI BELPSDA BELPSPPW1 BELPSBPW1 BELPSDPW2 BELPSDPW2 BELPSDPW2 BELPSDPW3 BELPSDPW3 BELPSDPW4 BELPSDPW4 BLPSDPW4 BELPS0PW3 BLPSDPWS BELPSDPW5 BELPSDPW5 BLENI TWO BLENI-TW7 BLENI W1SA BLENISLEPS1 LHPSD1 LHPSD1 LHPSD1 LHPSD1 LHPSP1 LHPSD1 LHPSD1 LHPSOS LHPSK LHP5K LHPSK LHPSK LHPSD LHPSD LHPSD 7 LHPSK2 LHPSD 3 LHPSD3 Snmpl* Dato 3/612002 - 3/6/2002 4/25/2002 3/8/2002 3/6/2002 4/25/2002 3/6/2002 3/6/2002 3/6/2002 3/6/2002 mam 3/25/2002 4/23/2002 2/7/2002 3/2502002 2/7/2002 mam 3/2&2002 3/25/2002 4&3/202 ` 2/7/2062 3/25/2002 4/23/2002 2/7/2002 3/25/2002 4/23/2002 4/23/2002 2/21/2002 2/21/2002 2/21/2002 1/30/2002 12/20/2001 1/21/2002 2/22/2002 3/20/2002 4/23/2005 6/21/2005 10/16/200! 12/20/2001 12/20/200 1/21/200! 2/22/200, 2/22/200'2 3/26/200 2 4/23/2002 8/21/200 2 MU16/2002 12/20/200 %1/21/200 C-8 ug/l N ('0.050) NQ(<0.050) NQ {<0.050) 0.0603 0,0686 0.0746 ND {<0,010) ND (<0,010) ND (<0.010) MD {<0.010) 0.0318 0.113 0.12 0.0995 0.13 NQ {<0050) NQ {<0.050) NQ {<0.050) 0.141 0.12 0,101 0.133 0-114 0.107 0.103 0.1D7 0.111 ND 0,010 NQ {<0.050 0,316 0.165 1.85 1.72 2.3/ 2.0! 2.05 3.6! 3.4 3,75 3.51 2.9 2.01 2.0 3? 1 3.4 4.2 6 3.08 0.844 0.744 Comment* 1 Before Treatment Sample! AfterTreatment Sample] AfterTreatment Samplej Production Well duplicate Production Well Production Well Production Wei! Production Well Production Well After Treatment Sample After Treatment Sample Alter Treatment Sample Production Well Production well Production Weil duplicate Production Well Production Well Production Well Production Wen Production Well Productionw ell Production Well Production Watt Production Well duplicate Test well! Teat wen Test well DiWtifw SupplyWell Production W ell ProductionWe# Production Wei) production Well Production Well Production Well Production Well Production Well duplicate Production We# Production Well Production Well Production Well Production Well Production Well Production Well Production Weil ProductionWell 1/29/2003 1of 5 Tab 3.13 Consent Order T&P.XS ASH021721 EID639953 I \ Table 3,13 Sum m ary o f C-8 In G roundw ater Public W ater Supplies W est Virginia and Ohio Dupont W ashington W orte Facility, W ashington WV Location U lte Hocking, OH (com.) , ' General S edile, WV Lubeck, WV Sample ID LHPSD3 JLHPSD3 LHPSD3 LHPSD3 LHPSD3 IH P 5D 3 LHPSC5 LHPSD5 LHPSD5 LHPSD5 LHPSD5 LHPSD5 LHPSD6 LHP3D5 LHPSDEP001 LHPSDEPQ01 IHPSDEPD01 LHPSDEPO01 IH PS0TW 1 LHPSDTW1 LHPSOTWtD LHPSDTOtO ~ LHPSDTW11 UIPSDTW11 LHPSDTW12 LHPSDTW12 LHP3DTW2 LHPSDTW2 LHPS0TW3 LHPSDTW3 LHPSDTW4 LHPSDTW4 LHPSDTW4 LHPSDTW4 LHPSDTW4 LHPSDTW5 LHPSDTW0 LHPSDTW6 ~ lh pso tvw LHPSDTW9 LHPSDTWS IHTORCH0S BARTLETTOC 3396 SW g w ell; ge w ell: GE w e l l : gew ell: LPSDA1 _________ LPSPA11* Sample D ati 2/22/2032 3/28/2002 4/23/2002 8/21/2002 1W1B/20Q2 10/18/2002 12/20/2001 1/21/2002 1/21/2002 212212002 3/26/2002 4/23/2002 8/21/2002 10/16/2002 1/22/2002 3/26/2002 4/23/2002 10/16/2002 1/22/2002 0/21/2002 1/21/2002 8/21/2002 1/21/2002 8/21/2002 1/21/2002 0/21/2002 1/22/2002 0/21/2002 1/22/2002 0/21/2002 1/22/20Q2 3/28/2002 4/23/2002 0/21/2002 10/16/2002 0/21/2002 1/22/2002 0/21/2000 8/21/2002 1/22/2000 8/21/2002 1/22/2002 1/22/2005 1/ 22/200; 1/3/200; 1/3/2001 > 2/21/2001 4/26/200! 3/28/200' 4/26/2; C -ftug/l 0.42 0.827 0.783 0.962 0.495 0.434 7.66 822 8.14 5,89 6.57 6,11 8.00 8.58 19 2.62 1.93 459 2.16 0.81 1.9 1.1 1.41 1.73 0.75 0,824 0.103 0.081 4.48 4.17 37.1 33.3 287 12.3 14.S 65i 1.7 1.1 1,2: 0,36/ 0.811 Li 1.91.8 17 5 1.8 j 1.7 5 1.84 0.6 9 0.65 2 com m ent* Production Well Production Well Production Well Production Well Production well duplicate production Well production Well duplicale Production Welt Production Well production Well Production Well Production Well Water System Point Water System Point Water System Peint Water System Point Test well Test well . Test well Test well Test well Test well Test well Test wli Teel well Test we!) Tesi well Test wall Tesi well Test well Test well Testwel Test well Teel well Tesiwell Testwel) duplicate Test wen Testwel Water System Point Water System Point Water System Point Production Well duplicate Production Wen Production We# After Treatment sample After Treatment Sample 1/29/2003 2 of S Tab 3-13 C onsent O rd e r T& F .xls A S B 0 2 7 2 2 1ID639954 Table 3.13 Summary of C-8 In Groundwater Publie Water Supplies, West Virginia and Ohio Dupont Washington Works Facility, Washington WV L o ifo Lubeck, WV (com.) Belleville Hydra Plant WV Toppers haine PSD, H - ......... .......... Sample lb IPSDAT LP5DAT LPSDWELLA IPSO WELL A LPSDWELLA LPSDW BXA lpsdw bxa LPSDWELLA LPSO WELL B LPSD WELL B LPSD WELL 8 LPSD WELL B LPSD WELL B LPSD WELL C LPSD WELL C LPSD WELL C LPSD WELL C LPSD WELL C LPSD WELL C LPSD WELL D LPSD WELLE) LPSD WELL D LPSD WELL D LPSD WELL D LPSD WELL D LPSD WELL LPSD WELL E LPSD WELLE LPSD WELLE LPSD W H X E LPSD WELLE LPSD w a x F LPSD WELL F LPSD WELL F LPSD WELL F LPSD WELL F LPSD W H X F LPSD WELL F LPSD WELL F BELLEVILLELD TPPSDPT TPPSDPT TPPSDPT TPPSDPT TPPSDAT TPPSDAT TPPSDAT TPPSDAT TPPSDAT TPPSDPW1 Sample Date 6/24/2002 10/15/2002 113/2002 2/21/2002 3/28/2002 4/26/2002 7/24/2002 10/15/2002 2/21/2002 3/28/2002 4/26/2002 7/24/2002 10/15/2602 1/3/2002 2/21/2002 3/28/2002 4/26/2002 7/24/2002 10/15/2002 1/3/2002 2/21/2002 3/28/2002 4/26/2002 7/24/2002 10/15/2002 1/3/2002 2/21/2002 3/20/2002 4/26/2002 7/24/2002 10/15/2002 1/3/2002 2ffi/2002 3/20/2002 3/20/2002 4/26/2002 7/24/2002 7/24/2062 10/15/2002 1/20/2002 2/8/2002 3/25/2002 7/23/2002 10/15/2002 2/84/002 3/25/2002 4/24/2002 7/23/2002 10/15/2002 216/2002 " . C S u s /l 0.6 0,653 0.764 0,683 0.706 0.B3B 0.753 OSSO 0,51 0.551 0532 0.443 0.537 0.592 0.479 0.491 0.471 0.398 0604 0.758 0.725 0.692 0.500 0.444 DJ517 0332 1 169 1.11 1.02 1/21 1.04 0313 03S8 0.352 0.332 0,284 0X83 0.355 NQ (<0.050) 0.372 0.347 0X4 0.226 0X61 0,358 0.363 0,24 0.268 0.726 Comment# || After Treatment Sample After Treatment Sample ProductionWell Production Weft Production Wet Production Well Production Well ProdustlonWell Production Well Production Wel) Production Well Production Well Production W ei Production Well Production Wen Production Well Production Well production Well Production W ell ProducionWelt Production Wol) Production Well production Well Production Well Production We!) Production Well ProductionWell production W ell Production Well Production Well Production Well Production Well Production Well Production Well duplicate Production Well Production Well duplicate Production W eil Miscellaneous Use Before Treatment Sample Before Treatment Sample Before Treatment Sample Before Treatment Sample Aller Treatment Sample After Treatment Sample After Treatment Sample After Treatment Sample After Treatment Sample Production Well 1/29/2003 3 of 5 Tab 3.13 Consent Order T&F.xIs ASH021723 1ID 639955 Table 3,13 Summary of C-S In Groundwater Public Water Supplies, West Virginia and Ohio Dupont Washington Works Facility, Washington WV Location Tirppars Plains PSD, OH leant.) _ " Sample IP TPPSDPW1 TPPSDPW1 TPPSDPW1 Sample Date 3/2512002 4/24/2002 7/23/2002 TPPSDPW1 TPPSDPW2 10/15/2002 2/3/2002 PP8D PW 2 7PPSDPW2 3/25/2002 4/24/2002 1 TPP5DPW2 7/23/2002 " TPPSDPW2 10/15/2002 TPPSBPW3 2/5/2002 TPPSDPW3 TPPSDPW3 PPSDPW3 TPPSDPW4 PPSDPW4 TPPSDPW4 TPPSDPW4 3/25/2002 7/23/2002 10/15/2002 ' 2/5/2002 3/23/2002 7/23/2002 10/15/2002 TPPSDPW5 TPPSDPW5 TPPSDPW5 2/5/2002 3/25/2002 7/23/2002 .... TPPSDPW5 10/15/2002 TPPSDPW6 2/5/2002 TPPSDPW8 TPP5BPW6 TPPSDPW6 3/25/2002 4/24/2002 7/23/2002 PPSDPW6 10/15/2002 Raveitsvrood Municipal,WV CRASIt C O R A S O lff 3/27/2002 3/27/2002 " n n p Rl Nn AT 3/27/2002 CORWEU1 3/27/200; 1 Mason County PSD, WV ~ I1~" COR WELL c o r w ell: COR W SJ-' COR WELL! m aso nc psd ' MASONCPSD MASONCPSD MASONCPSD3 " MASONCPSD2 MASONCPSD2 MASONCPSD3 MASONCPSD3 MASONCPSD3 3/27/200: 3/27/2001 3/27/26(5 3/27/200- 1/29/200 3/27/200'2 4/25/2002 1/29/2002 3/27(2002 4/25/2002 1/2912002 3/27/2002 4/25/200 Ratino Lada and Dam.WV Village of Racine, OH ........ RACINBJ } VORAt VORKV3 VORWEU 1 ____________ VORWEU2 1/4/201 2 3/26/200 3/26/200 3/26/20012 3/26/201 12 New Haven Water Dept.. WV NHPSDAT NHPSDPV, 1 4/10/201 4/1D/201B C o tta li 0.705 0.702 0.588 0,486 0.417 0.327 0.371 0.235 0255 NQ (<0.050) NQ (<0.050) ND 0.010) ND 0.010) 0,0734 0.07 0.652 0,076 0201 0401 0.216 0229 0.649 0.634 0.62 0.62 0,433 NQ 0.050) ND 0,010) ND 04)10] ND 0.010 ND 8.010 ND 04)10 ND (<0.010 NQ 0.050 NQ 8,050 0.0611 0.083 0.071 0.070 0.10 0,063 051 1 nd .oil)) ND 0.011j| ND ('0.011j> NQ 0.061 Comment production Well Production Well Production Well Production Wall Production Wall Production We Production Well Production W ei Production Well Production Well productionWell Production Well Production W ei Production W ei Production well Production Well Production Well Production Welt production Well Production Well Production Well Production Well production Well production Well Production Well Air stdDoar In Air Stripper Out Blend Altar Treatment production Well ProductionWall Production We Production Watt Production Welt Production Wen ProductionWei) ProductionWe8| Production Well production WeB Production Wall Production We# Production Wei Miscellaneous Use production WeB production Wo# production WbB . ProductionWeH 1/29/2003 4 Of5 Tab 3.13 Consent Order T&F.xIs ASB021724 ID639956 Tabi 3.13 Summary of C8 In Groundwater Publie Water Supplies, W est Virginia and Ohio Dupont Washington Works Facility, Washington WV I Location Wi~NewHaven Water Dept., j Vilage ol Syracuse. OH ~ Sample IP ..... NHPSDPW1 VOSAT V0SAT " VOS NORTH 2 VOS NORTH 2 VOS SOUTH R3 VOS SOUTH R3 Vllage of Pomeroy, OH VOPAT VOPAT VOPWELL1 V0PWBJL2 VOPWELL2 VOPWELU VOPW BH Sample Pate 4/100002 3/200002 4/240002 3090002 4040002 3/260002 404/2002 3060002 4040002 4/240002 3/26/2005 4/240002 3/260002 4040002 OO ug/l NQ{<0.060) NQ (-c0.050) ND (<0.010) NQ (<0.050) 0.491 oosa ND {<0.010) 0.0020 ND {<0.0101 0.0680 ND(<0.010 0,0851 0.0713 Comments 1 duplicate AlterTreatment Sample AfterTreatment Semple ProductionW ei Production Welt Production W et Production W ei AfterTreatment Sample AfterTreatment Semple Procjuciion Wen Production We# Production W ei Production W ei Production W elf MOs NotDetectedatorabovetheDmitOldetection(LOD). Tltenoted LODi$approximateandvariesbyinstrumenlandoverIme, NQbNotQuantifiable. DetectedatalevelabovetheLODandbelowthe limitofquantitation(.OQ), AllOS resultsamreportedinufl/l. Mlsc. =MiscellaneouswateruseIsnotusedfordrinking. 1/29/2003 Sof5 Tab 3.13 Consent OrderT8F.xls ASH021725 E ID 639957 Table 3.14 Synoptic groundwater Elevations February 2002 and Well Screen Locations DuPont Washington Works Facility Washington, West Virginia New ID Measuring Point Elevation (feet) * ~ 635.22 At-10-MWOI AOOe-MWOI AO09-MWO1 AR09-MW01 631.61 8364 632.89 635.27 635.23 680.67 pfifU M V d0 4 681.14 I7-MW01 joa-Mwoi 610.23 630.21 627.34 L1B"M W 0l 635.82 627,14 594,48 1 M 1& JA M M 625.67 629.29 Y lA A /A A /ftl U16-MW1 vn&Mwni 598.76 632.69 631.17 638.23 628.5 631.16 632.49 599.95 AAfRMWft1 633,32 A11*MW1 E13-MWQ1 017*MWO1 Mn4-MW62 633.02 628.94 625.47 632.61 595.51 M04-MW03 N04-MW02 KiWvMWOI P04*MWO2 ' P0&M W 02 RO4-MW02 S05-MW2 U04-MW01 v o i-m w o i W05-MW1 Y14-MW01 Z05-MW02 Z7-MWQ1 I Z09WW01__ _ 595.43 595.82 633.17 582.39 63124 594.92 639.64 595.43 629.49 ' 629.9 64225 629.21 632.98 624.65 DM ID TW -E8 TW-M1 TW-48 TW-28 TW"3B TW -38 TW -M 5 TW-M8 TW-M3 TW -20 TW-M4 tw -27 TW -55 TW -32 TW -54 TW -53 TW -50 TV/-24 TW -P12 TW -25 TW-3(pW-3) TW -E5 TW -22 TW -70 TW-71 TW -72 TW*74 TW -76 TW -77 TW -79 TW -ao TW-81 TW -82 TW -83 TW -64 TW -65 TW`86 TW -67 TW -08 TW -89 TW-9 TW -91 TW -82 TW -93 February 2002 D tW 68:6 67.12 70.32 73.81 37.98 38.9 49.16 6825 78.87 68.9 16.46 65.95 69.19 38.71 71.59 79,02 76.5 67.38 67.48 67.9 34.4 67.71 67.41 62.92 64.35 73.35 13.42 13.93 13.78 73.18 20.48 71.14 18.63 71.60 11,97 70.53 70.42 80.1 652 68.97 60.95 * A l Measuring Point Elevation data Is #om Vanen surveys In 1989 or 1998. February 2002 Groundwater Elevation (feet) 566.62 S64.49 562.57 56029 581,42 562.69 562.24 561.05 90 41 559.09 556.95 558.24 578.02 559.92 560,1 560.05 561.1 '652.15 61.73 561.12 563.68 564.59 565.55 565,61 565.61 596^2 561,12 559.46 562.09 581.5 582.04 559.99 571.91 560.1 576.39 558.98 583.46 558.96 559.48 562.16 564.01 564.01 563.7 ------- Screen Location Sits priman/ aquifer its orimarv aquifer tits primary aquifer rite primary aquifer rite primary aquifer rite primary aquifer rite primary aquifer site orimarv aquifer trite primary aquifer site orimarv aquifer site orimarv aquifer site orimarv aquifer site orimarv aquifer perched water table site Drimary aquifer site primary aquifer site primary aquifer site Drimarv aquifer site orimary aquifer site orimarv aquifer site orimary aquifer site orimary aquifer site orimarv aquifer site orimarv aquifer site orimarv aquifer site orimarv aquifer | _ site orimarv aquifer site orimary aquifer site primary aquifer oarched water table perched water table Derched water table site orimarv aquifer ... oerehed water table site Drimary aquifer oerehed water table site primary aquifer perched water table site orimary aquifer site primary aquifer site primary aquifer site primary aquifer site primary aquifer site primary aquifer 1/29/2003 1 Of 1 T a b 3 .1 4 C o n s e n t O rd e r T & F .xIs A SH 021726 ED639958 Table 3.15 Summary of On-site and Off-site Exposure Pathways Evaluation DuPont Washington Works Facility ! I 1 f 2 I 1 M *0 1 i : ....... - V .* O n-S ite SWMUs/Land filled Materials Soil Surface Water . Groundwater Drinking water (to n groundwater) Process water (from groundwater) Pathway Assessm ent (Complete (Q or incom plete (1)1 1 1 i 1 C C Com parison to Screening C riteria* uqri 150 ug/l 5 1 2 uo/I < 150 un/l Exposure Pathwayis fo r Ecoloctca! Receptors Pathw ay Assessm ent (C om plete or incom plete) 1 1 1 f NA m Com pttdson to Screening C rite ria* - -- - O ff-S its C-8 Im pacted Media Drinking W ater (wells, springs andior cisterns) - W V Non-drinking water (wells, springs and/or cisterns) - WV Exposure Pathways fo r Human and Ecological Receptors Pathway Assessment [Com plete (C> or Incom plete (1)1 Com parison to Screening C riteria* C 2,8 ug/1 150 ti.q/1 C 5.07 uo/1 <150 ug/l Unused water sources - WV Drinking W ater (wetta, springs and/or cisterns) - OH Non-drinking water (wells, springs and/or cisterns) - OH i c c 8.59 un/l 150 tig/l 23.6 un/l < 1 5 0 ug/i ,. .... Unused water sources - OH Ohio River water PWS (WV and OH)______________ 1 c c 1.09 u o /i 150 un/l 4.29 un/l 150 un/l * Highest vaiue In category is compared to the screening criteria Screen ng criteria was established by CATT of 24 mgrtsg for sioil, 1360 ug/l for aquatic life (surface w.ater), 150 ugfl for drinking water. For complete exposure pafthvrays, all water'samples are connpared to the drirtdhg water screening criteria to be pleie exposure pathways i 1/30/2003 1 off Tab 3.15 Consent Order T&r.xte ASH021727 i IB639960 I I I & O' NH>* -J *0 Table 4.0 Monitoring Weil Construction and Groundwater Elevation Data Local Landfill Washington, W V -- .... .....-- ............. ...... ............ ' i . 4~- Param eters M easuring Point LLMW-4 LLMW-6 847.55 796.27 Total. D epth (feat) Weil D iam eter Slot ' 157.1 4 0 02 93.09 4 0.020 Screen interval 20 710.45 '690.45 20 723.18703.18 Decernbe r-0t J a n u a r y -02 1F e b ru a ry -02 M arch-02 May-02 A ugust-02 O cto b er-0 2 692.55 715.39 715.26 715.31 714.93 715.52 715.53 71939 720.41 719.76 722.00 721.52 719.7? I 719.58 LLMW-9 LILMW-t LLMW-12B | LLMW-11 : -V 'GMpa LLMW-13B LLMW-14B :I D -Z one . !| LLMW-11B j 788.54 805.94 764.28 I 663.83 81,39 87.75 94.94 42.37 44 22 0.020 0.020 - 0.010 0.010 20 727.15707.15 727.78 728.06 728.01 728.12 728.48 728.24 728.10 20 738.19 i 718.19 j 720.67 720.51 720.73 720.90 721.64 722.97 723.01 20 20 689.34 - 641.46 - 689.34 ; 621.48 ion (feet) 681.93 640.42 750.80 672.04 139.87 57.28 22 0.010 0.010 15 625.93 610.93 15 629.76614.76 :; 646.29 627.74 665.12 115.95 2 0.010 20 569.17 549.17 563:.60 I 1/29/2003 Tab 4.0 Consent Order T&Fjds *t Table 4.1 Summary of Analytical Results: C-8 in Groundwater Local Landfill Washington, WV S am ple r-- LLMW-4 LLMW-6 LLMW-9 I Date 1 AZona 10/15/2002 512012m9/3/2002 3/28/2002 ----mimz2/26/2002 12/13/2001 5/16/2001 5/11/2000 5/19/1999 5/27/1998 ... 4/11/1996 10/15/2002 10/15/02 (dUDi 9/3/2002 5/20/2002 3/26/2002 2/25/2002 1/27/2002 12/13/2001 5/16/2001 5/10/2000 5/19/1999 5/27/1998 4/11/1996 10/15/2002 imimi9/3/2002 3/28/2002 2/25/2002 1/27/2002 12/13/2001 5/16/2001 5/10/2000 5/20/1999 5/27/1998 4/11/1996 C*8 (ug/i) 79.6 63.5 55.7 47.2 50.2 58.4 54.6 1.40 10 16.2 26 39 19.9 17 13.7 18.6 11.5 10.1 12.2 11.9 3 1.42 1.32 9 15 0.0569 NO NO NQ NO NO ND 0,039 J <0.029 0.048 J <0.1 0.14 . I 1/29/2003 1 of 2 Tab 4,1 Consent Order TSF.xls SH021729 EID639961 ta b le 4.1 Summary of Analytical Results: C-8 In Groundwater Local Landfill Washington, WV S am ple LLMW-10 ' " " ............. , ' LLMW-12B . - .... ...... LLMW-11A LLMW-13B LLMW-14B .............v - LLMW'11B D ate 10/15/2002 9/3/2002 5/20/2002 3/28/2002 2/25/2002 /27/2002 12/13/2001 5/20/1999 5/28/1998 B-Zone | 10/8/2002 I ozen# 10/8/2002 10/8/2002 10/9/2002 w arne I 10/8/2002 . ..... 1 c-8(ufl/n 0.3S5 0.357 0.56 0.698 1.12 0.162 0.133 0.15 0.22 0.0658 ......... 2.22 6.61 0.488 NQ(<0.05) J=>isHmatedvalue(belowlaboratoryquantitationlirnll) ND=NotDetectedatorabovethelimitofdetection(LOD) . NO3NotQuantifiable. DetectedataconcentrationabovetheLODendbelowtheUnlitotquantification <LOQ>. Note: Analytical methodchangedas of November2001 (seeSection2-0fordetails). 1/29/2003 2 of 2 Tab 4.1 C onsent Order T&F.xIs ASH02173 EID639962 Table 4.2 Summary of Analytical Results; 0 8 in Surface Water Local Landfill Washington, WV Sam ple OUTFALL 004 (New) P a te 11/30/2002 10/31/2002 9/30/2002 8/26/2002 7/1/2002 6/13/2002 6/21/2002 4/29/2002 3/26/2002 OUTFALL 004 (Old) 16/31/2002 9/30/2002 8/26/2002 7/1/2002 6/13/2002 5/21/2002 4/29/2002 3/26/2002 2/20/2002 1/24/2002 12/13/2001 9/27/2000 12/10/1999 6/3/1999 6/2/1998 5/29/1997 4/2/1996 .... 2/16/1994 dUTFALL 005 (New) .... 11/30/2002 10/31/2002 9/30/2002 8/26/2002 7/1/2002 6/13/2002 5/21/2002 I .. 4/29/2002 3/26/2002 i roa L c -a (uii/i) No-flow conditions No-How conditions No-tlow conditions No-flow conditions 11.2 9.29 No-flow conditions 14.5 14.6 No-flow conditions No-flow conditions No-flow conditions No-flow conditions 11.6 10 No-flow conditions 15 1.54 10.9 11.4 No-flow conditions 473 7.1 3.06 12 13 13 11 No-flow conditions No-ftow conditions No-flow conditions No-flow conditions No-flow conditions No-flow conditions No-ftow conditions 34J 16 _ .... II 1 1 | __ _ I 1/29/2003 1of 2 Tab 4 2 Consent O rder T&F.xls ASH02X731 EID639963 Table 4.2 Summary of Analytical Results: 0 8 in Surface Water Local Landfill Washington, WV S am ple OUTFALL 005 (Old)/SS1 OUTLET 101 LNI1 (LeachateVInlet 002 D ate ii//2W >2 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 i/ilM 0 2 I 2/T3/20T 9/27/2000 12/10/1999 6/3/1999 6/2/1998 5/29/1997 4/2/1996 2/16/1994 11/19/2002 10/31/2002 9/30/2002 ...... 8/26/2002 7/1/2002 6/13/2002 6/21/2002 4/29/2002 3/25/2002 2/20/2002 1/23/2002 12/13/2001 9/14/2000 6/3/1999 6/2/1998 11/21/2002 J ' 08(unm No-flow conditions No-flow conditions No-flow conditions No-flow conditions 32.1 27.3 No-fiow conditions 40.9 39 .46 51.4 No-flow conditions 13.3 34 6,8 39 41 39 35 76.7 78.6 115 70.3 63 38 40 48.2 36.4 63.1 81.4 82.4 12 15 54 120 Note: Analytical method changed as of November 2001 (see Section 2.0 of OuPont (2003b)tor details). 1/29/2003 ' f r. 2 of 2 Tab 4.2 Consent Order T&F.xls ASH02X732 EID639964 Table 4.3 Summary of On-site and Off-site Exposure Pathways Evaluation Local Landfill i|..wg y C-8 Im pacted O n-Site SWMUs/Landfiiled Materials Soi Leachate Surface Water Groundwater C-8 Im pacted Media Off-Site Drinking"Water (wells, springs and/or cisterns) Local ___________ Non-drlnklng w ater (wells,' springs and/or cisterns) L oca) ............ _ Human Health Exposure Pathw ays Pathw ay A ssessm ent (Complete or Comparison to Screening i n c o m p l e t e ) _______ Criteria* I I C 120 agri < 1~50~ug/i C* " t t S iig/1< ISO ugTi Ecological E xpoeure Pathw ays Pathw ay A ssessm ent (Compiete or C om parison to Screening In com ple t e ) ____ _ C riteria* 1_ . -- i. C 'C ' 1 5 tig/i < 150 ug/i Exposure Pathw ays for Human an d Ecological _________________ R ecep to rs____________ _______ Pathw ay A ssessm ent [Com piete (C) o r C om parison to S cre e n in g incom plete # ] C rite ria * ________ jy j u j/l 150 ug/i <150 ug/i Unused water sources ____ i * H ighest value In category is com pared t i e screening criteria. Screening criteria w a s established by C A T !o f 2 4 0 mg/kg for soil, 1360 ug/i for a g tra ic lie (surface w ater), 150 ug/i for drinking w ater. For complete, all w ater sam p les are com pared to th e drinking w ater screening criteria to be conservative. No com parison is m ade far Incomplete exposure pathways. ...... 1/30/2003 1of 1 Tab 4.3 Consent OrderT&F-xis Table 5.0 Summary of Off-site Sampling Program (C-8 Sampling) Letart Landfill Letart, WV 7 r r "Mi SIDENTIAL SAMPLING FOR 1-MILE RADIUS .. ....... Homes Number of homes contacted(1) ' 1 1 48 Number of homes surveyed(1) 46 111 Number of wells identified<2) Number of wells sampled ^ 42 30 1 Number of wells sampled that are used for drinking water 11 Number of cisterns identified(2) Number of cisterns sampled 125 O Number of cisterns sampled that are used for drinking water Number of springs identified m Number of springs sampled<2) 4 0 0 0 0 Number of springs sampled that are used for drinking water Total number of samples 0 30 Total number of collected samples used for drinking water 11 [sam ples Springs Note: Field duplicates not considered in sam ple count. 0) During thig investigation, homeowners/residents identified with! the sampling radius were contacted to determine residential water usage. Up to two contacts were attempted a t each residence. After the second contact attempt, a voluntary survey w as left at the residence. B ecause not all homeow nere/residences to the survey, the number of residences surveyed is less than the number of homes contacted. |2,Som e w ater sources (e.g. wells, cisterns, springs) identified during the survey w ere not sam pled. In many case s, sampling of th ese water sources w as refused by the homeowners/residents. In other cases, the w ater sources w ere either not accessible or damaged. As a consequence, the number of water sources sampled w as less than th e num ber of w ater sources identified. 2/4/2003 1 o ff Tab 5.0 C onsent Order T&F.xls A SH 021734 1X D 639966 STZOHSTf a i: i 1 II Table S.1 Summary of G-8 Analytical Results In Groundwater (ug/i) Letart Landfill (Off-slte W ells - One Mile Radius) Letart, WV Sam ple ID OS-BRINKERA O S -0U TY K I O S -G E R L A C H L 08-Q R1M M Q OS-G RM M R OS-JRDANS1 O S -JU D Q E T O S-PARSO NSB O S-SAYRET Sem ate Bate 12/ 11/2001 12/12/2001 12/ 11/2001 1 2/10*001 12/11/2001 1/17/2002 12/10/2001 12/14/2001 12/11/2001 Wl U fl/Il 0 .1 3 9 NO (0.0105 ND (ODIO) NO (0.010) NO (0.010) NO (ODIO) NO (0.010) NO (0.010) NQ (<0,0505 ..r m w Com m ents . ' S em ple ID Drinkinq W aterl 05-G ER LA C H B A O S -G E R L A C K C O S-G RM M R2 O S -0O R D A N S 2 Drinkinq W aterl O S-JO R D AN 83 O S -K E A R N S M G i O S -P A iN T E R J OS-PA R SCN SR 2 Drinkinq W aterl OS-RiCHAROSONO S am ple Bate 1 /1 6 /2 0 0 2 12/14/2001 1/16/2002 1/17/2002 1/17/2002 12/10/2001 12/11/2001 2 /2 7 /2 0 0 2 12/11/2001 O S -S H E L D S D 12/10/2001 NO (0.0105 O S -R O T T G E N R D 1/16/2002 OS-STEW ARTA OS-STEW ARTA O S -B IG B E N D 8H C DUPO NT LET1 O S -F R IE N D W OS-FR1ENDW 12/13/2001 1 2/13*001 1 /2 4 *0 0 2 1 /1 7 *0 0 2 1/16/2002 1/16/2002 N Q (<0.050) MD (<00505 NO KMHO) NQ (<0.050) ND (0.010) ND (0.010) Drinkinq W aterl Drinkinq W ater, duphcatel Unused Unused! Unused, duplicate | ' OS-SLEETHTR QS-STEW ARTA2 O S -T H A C K E R C OS-THO M ASC O S -TH O M A S U O S -V A U G H A N J 1/17/2002 2 *7 /2 0 0 2 1 2/1 2*0 01 12/10/2001 12/12/2001 12/13/2001 ' Drinking W ater (hlahlkjtr e d iti ttoid Hue) W icates hum aneonsuntpon. Nondrinking W ater uses include livestock watering, garden consumption water uses. ND N o t Detected at or above the t o il of detection (LOD). byThe feted LOO is approxim ate and varies instrument and over time. NO N o t Quantifiable. Detected a ! a concentration above fits LO D and betow the limit c l quantification (LO O ). A I!C -a results are reported in tig /l. Miscellaneous w ater use is not used tor drinking. I 1 i t "J-------------------- 1-- 1W ell U ae^ Com m ents! 0 .6 3 6 NO (0.010) h (0 .0 1 0) ND (0 .0 1 0) ND (0 .0 1 0) ND (0 .0 1 0) Unused M iscetan eo us Unused Unused Unused iM iscelaneous ND (0 ,0 1 0) N D (0 ,0 1 0) ND (0.010) N D (0 .0 1 0) NO (0 .0 1 0) N D (0 .0 1 0) NQ ( 0.0 50 ) ND (0 .0 1 0) ND (0 .0 1 0) N D (0 .0 1 0) (Miscetaneous Unused M fecelartebus Unused Unused Unused M Iscelanecu s MEscelaneous Uiacelaneous 4 Hoat 1/20/2003 10:11 AM 1 oft Tab 5.1 Consent Order T&F.xis ?! fa b le 5.2 Monitoring; Well Construction and Groundwater Elevation Data Letart Landfill Letart, WV Param eters M easuring Point Elevation (feet) LMW-13A LMW-14A LMW-2A 766.25 766.91 780.67 Total D ep th (Teat)_______ 152.35 156.72 182.17 Well D iam eter {Inches} S lo t Size {inches} .4 .0.010 4 0.010 4 0.010 S creen Length (feet) Elevation of Screen Interval (feet) D ecem ber-01 January-02 February-02 M arch-02 May-02 A u g u st-0 2 O cto b er-0 2 20 20 30 655.10- 628.19- 635.10 606.19 1 " ... ,r^ ^ s e s r 628.70 598.70 621.07 627.04 NA 622.19 62223 622.44 622.28 622.44 622.30 NA = Instrument limitations 1/29/2003 LMW-6 LMW-10 hr LMW-11 LMW-13B LMW-14S LMW-9 755.99 176.43 4 0.010 30 734.37 191.55 4 0.010 20 77621 166.54 4 0.010 25 765.86 19227 4 0.010 20 767.10 202.00 4 0.010 20 777.85 230.87 4 0.010 20 609.56 - 562.82 - 634.67- &apppp679.56 542.02 609.67 NA 582,26 581.97 581,82 581.97 582.34 582.05 NA. 543.37 543.36 543.39 543.39 543.26 543.35 NA 019.58 620.70 620.99 621.28 621.52 621.10 593.59 : 573.59 585.10565.10 566.98 - 546.98 682.86 I 569.31 NA 552.12 .551.93 551.79 55124 l 552.51 1 551.73 2 of 2 Tab 5.2 Consent Order T&F.xis ASH021736 Table 5.2 Monitoring Wed Construction and Groundwater Elevation Data Letart Landfill Letart, WV Becember-01 Ja n u a ry >02 February-02 M arch-02 May-02 A ugust-02 O ctober-02 752.62 752.82 752.65 752.10 75027 751.98 751.02 749.73 | 75225 751.87 751.56 751.16 I 751.49 I 751.75 745.04 746.76 745.05 746.24 745.41 744.96 745.43 | 64&S2 648.19 648.07 648.47 646.74 646.53 646.77 NA = Instrum ent fimitaHons 1/26/2003 1 of 2 61922 618.76 618.10 617.61 617.50 017.36 61723 617.4 616.76 615.37 614.80 615.27 615.54 615.84 642.79 639.99 643.30 643.08 636.02 632.47 590.64 595.34 596.86 596.66 596.25 598.86 635.47 Tab 5.2 Consent Order T&F.xts Table 5.3 Summary of Analytical Results: C-8 in Groundwater Letart Landfill L etarL W 1/29/2003 10f4 Table 5.3 Consent OMer T&F.xls ASH021738 EX D 639970 1/29/2003 Tabi 5.3 Summary of Analytical Results: C S In Groundwater Letart Landfill Letart, W V ,-r -- - -- C*Zori Wails '-- . . . . . " . . . . . . . . [ = Samolo " ....... LMW-3 ' Data 10/11/2002 T " sm am m5/24/2 . " 3/27/2002 2/24/2002 NQ 0.051 Div no sample 2270 1780 16 ... . 1 1/29/2002 * 12/13/2001 11/22/1901 1700 18 1000 1 3/22/1991 390 I.M W -fiA 10/11/2002 8/26/2002 112 Dry no sample 6/21/2002 87.6 3/27/2002 93.8 2/23/2002 1/26/2002 822 693 12/11/2001 94.4 ...... I 11/22/(991 0.6 3/22/1991 ... " 1.6 " Solinola LMYW3A D/E<Znae W alls D ate 10/11/2002 6/26/2002 . ....... ....... 1 e * (usto 204 Diy.no sar/iDls 5/24/2002 3/27/2002 2/23/2002 134 ... 132 101 . . . ... 1/26/2002 98.6 12/11/2001 7/19/1999 100 603 11/22/1991 3/22/1991 350 380 IM W -4 27/2002 2840 ........ . ... 1410 5/21/2002 1690 3/27/2002 20 2/23/2002 22SS 1/26/2002 3060 12/13/2601 1580 ... 4/3/2000 272 1/14/2000 172 11/22/1991 630 1 ! I' Santo!* LWW-5B 3/28/1991 . . D/E-Zono WaHs D al* 10/11/2002 10/11/02 (due) 690 C -B iu a m 2230 2280 1 8/27/2002 1480 6/27/02 (du al* 1340 5/21/2002 17 5/21/02 (du el* 1630 3/27/2002 1810 J I 1 1850 2/23/2002 1480 2/23/02MUP) 1430 1/26/2002 1780 ' 1/26/02 (due) i 12/11/2001 1890 1880 | 7/20/2001 483 1 7/20/01 (dup) 562 2ot4 Tabid 5.3 Consent Order T&F.xte A SH 021739 EID639971 1/29/2003 Table 5,3 Summary of Analytical Results: c-8 In Groundwater Letart Landfill Letart, WV ........ ' Sample LMW-12 LMW-13A LMW-14A .r , ^ ..... 8 *S i> l* . LMW-2A Sample IM W -8 J LMW'10 DiE-^one W ells IC o n t) Date 1/31/2001 10/5/2000 10/6/00 (dup) 7/25/2000 4/3/2000 4/3/00 (dual 1/14/2000 10/21/1999 615 1190.4 780 goo. J 1100 1020 10% 1750 . 10/21/09 (dupl 7/20/1999 7/23/1097 9/20/1994 3/16/1994 i i M im i _ 3/22/1991 10/10/2002 10/10/2002 10/10/2002 1700 445 480 530 1200 380 W" Dry-no sample 510 974 ....... F<2onW elb D ate 10/14/2002 8/27/2002 5/24/2002 3/29/2002 2/24/2002 ' 6 4 (n a /n 931 678 922 717 714 1/26/2002 12/11/2001 7/19/2001 1/30/2001 10/5/2000 7/25/2000 4/3/2000 1/14/2000 10/21/1999 7/20/1999 5/28/19% 7/23/1997 4/17/1900 9/20/1994 3/15/1094 11/22/1991 3/22/1991 740 830 242 423 246 275 308 453 370 350 980 480 480 270 260 03 50 . N tO M l W*Ks D el* 10/14/2002 a /27/2002 5/24/2002 3/29/2002 2/24/2002 1/28/2002 12/11/2001 1/13/2000 5/28/1998 11/22/1991 3/22/1991 10/17/2002 8/29/2002 5/21/2002 C4HUO/0 15.1 10.5 20.7 14.8 14,9 18.1 153 9.4 3 24 25 tnstfufli^meifcn probtems-Not a ! .... Pump probifimfi-Nol sampled 1 0JZ98 1 3 Of 4 Table 5J3 Consent Order T8F.xls A SH 02X 740 EID639972 Table 5,3 Summary o f Analytical Results: C-8 in Groundwater Letart Landfill LetarLW V 1' 1.............. ' M a li LMW-10 (C oni) L M W -I LM W -130 LM W -143 - .... _ . . . . . y rra r-- LMW-8 P ^ o n * W ells paw 3/27/2002 2/23/2002 1/26/2002 12/13/2001 10/14/2002 0/27/2002 5/21/2002 3/2B/202 2/24/2002 1/26/2002 12/11/2001 10/10/2002 10/10/2002 Under F >rWell Date ' 10/17/2002 ............ 0/28/2002 5/24/2002 3/27/2002 2 3 /2 0 0 2 1/26/2002 12/10/2001 10/7/1992 - 0.139 0.126 ..- 0.133 0.134 0.121 0.058 0.069 0.119 0.112 0.1S9 0.128 0.0956 105 ... M O ia ........ 0.007 0.479 0.71S 0,831 0.617 0.875 ....... 0.846 02 i estimatedvalue (belowlaboratoryquantitation limit). Note: Aft&Jytfclmethod hngdaS DfNVfftor 2001 <s#Section 2.0 of DuPont (2003b) fo details). Ana!vtle?Iduplicated values were previously toadvertantiv omitted bom the tables. 1/29/2003 4 of4 Table 5,3 Consent Order T&Pjds A SH 021741 EID639973 Table 5.4 Summary of Analytical Results; C-8 in Surface Water Letart Landfill Letart, WV I Sample 002(LEACHATE BASIN) ' . 1 003 STORMWATER RUNOFF RT 33 STREAM 1 I I 1 BRINKERRUN Date 11/25/2002 10/31/2002 9/27/2002 8/30/2002 7/30/2002 6/28/2002 5/30/2002 4/30/2002 3/26/2002 2/10/2002 1/25/2002 12/14/2001 11/27/2001 7/2O/2001 7/25/2000 4/3/2000 1/14/2000 10/21/1999 11/30/2002 10/31/2002 9/27/2002 8/30/2002 7/30/2002 6/28/2002 5/30/2002 4/30/2002 3/28/2002 2/19/2002 1/25/2002 12/14/2001 9/27/2002 10/31/2002 9/27/2002 5/30/2002 4/30/2002 3/28/2002 2/19/2002 1/25/2002 7/20/2001 7/31/2000 7/20/1999 7/23/1997 4/17/1996 10/14/2002 C-8(U0fl) 939 645 4.52 2050 1410 Not Analyzed* 1630 443 131 3 50.1 ..... 30.1 53.2 150 1350 1900 920 3240 No-Ftow Conditions No-Flow Conditions 0.17 No-FIcw Conditions No-Flow Conditions Not Analyzed* 0.282 0.0653 0.198 No-Plow Conditions 0.148 0.39 50.9 83 2.24 No-Flow Conditions 1.57 0.845 1.26 3.92 1.9 2.01 0.573 2.23 2 1.8 0.0612 1/29/2003 1 of2 Table 5.4 Consent Order T&F-xb A SH 021742 EID639974 Table 5.4 Summary of Analytical Results: C-8 in Surface Water Letart Landfill Letart, WV " . Sample CAP RUNOFF Date 11/25/2002 10/31/2002 8/30/2002 6/28/2002 5/30/2002 4/30/2002 3/28/2002 2/19/2002 1/25/2002 C -8 (u g /l) 65.1 102 No-Flow Conditions Not Analyzed* 371 279 Not Sampled No-Flow Conditions 119 Note: Analytical method changed as of November 2001 (see Section 2.0 of DuPont (2003b) lor details). > Samples were taken at the respective surface wafer 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 A SH 021743 EID639975 Table 5.5 Summary of On-site and Off-site Exposure Pathways Evaluation Letart Landfill Letart, WV ' Uc^ - Human H ealth E xposure Pathw ays -u.A.jt-. I .. . Ecological Exposure Pathw ays Pathw ay A ssessm ent (Complete or C-8 tm paoted Media Incom plete} O n-Site SWMLTs/Lantfflled Materials I Soli I L eachate ** C Surface W ater C Groundwater I Comparison to Screening Criteria* *2050U H /i> iso ug/l 371 ug/f > 150 ug/l '- jPathw ay A ssessm en t |(C om pteteor (Incom plete) I ] i~ l i i C C 1 Com parison to Screening Criteria* ~ *2 50ug/i>50ug/i 371 ug/l > 150 ugfl " Exposure Pathw ays for Human a n d Ecologica! j R ecep to rs I Pathway A ssessm ent [C om plete (C) o r C om parison to S creening : C -8lm pacied Media in co m p lete {111 Criteria* | O ffrile Drinking W ater Wells -.Letart Noivdrinking W itw WsHs - ....... .... -C-- --Sc!?9 9M < < 1 5 0 ug/l___ j Letart ____ ___ _ ........... Unused water sources Letart Ohio River water ............,__C ______ I c NQ(<0.05Q) 1 5 0 ug/J ................ - 0.128 u g / l 1 5 0 ugi/l j i" ! , t ' H ighest vafue in category is com pared to th e screening criteria. Screening criteria w a s established by CATT of 240 mg/kg for soil, 1360 ug/l for aquatic We (surface water), 150 ug/l for drinking w ater. For complete exposure pathways, a l w ater sarrtptes are com pared to the drinking w ater screening criteria to be co n se rv a im .M se ra B S d sm fe m a d e for incomplete exjxjsurejpathways,. , .............. ** H ighest C-6 concentration (since th e fandfiil c a p Installation In Aorii 2001) is shown. ... A5H021744 1/30/2003 t of 1 T ab 5.5 C o n sen t O rder T&F,xis Table 6.0 Summary of Off-site Sampling Program (C-8 Sampling) Dry Run Landfill Lubeck, WV ..... ... ... "* Eo X ' Number of homes contacted(1) Number of homes surveyed<1> Number of wells identified<2> Number of wells sampled(2) 75 64 41 37 Cisterns J W ells Number of wells sampled that are used for drinking.water Number of cisterns identified(2) Number of cisterns sampled(2) 13 17 8 Number of cisterns sampled that are used for drinking water Number of springs identified<2) Number of sprint sampledt2) 1 8 8 Springs Number of sprinqs sampled that are used for drinking water Total number of samples Bu & Total number of collected samples used for drinking water 1 53 15 Note: Field duplicates not considered in sam ple count. (1) During this investigation, homeowners/residents identified within the sampling radius w ere contacted to determine residential w ater u sag e. Up to two contacts w ere attem pted at each rsidence. After the second contact attempt, a voluntary survey w as left at the residence. B ecause not all hom eow ners/residences to the survey, the number of residences surveyed is less than the number of homes contacted. Som e w ater sources (e.g. wells, cisterns, springs) identified during the survey w ere not sampled. In many c a se s, sampling of th ese w ater so u rces was refused by the homeowners/residents. In other cases, th e w ater sources w ere either not accessible or damaged. As a consequence, the number of water sources sampled w as less than the number of water sources identified. 2/4/2003 loft Tab 6.0 Consent Order T&F.xls A SH 021745 EID639977 TABLE 6,1 Summary of C-8 Analytical Results In Groundwater and Surface Water (ug/i) Dry Run Landfill (Off-site Wells, Springs, and Cisterns - One Mile Radius) Lubeck, WV Sam ple ID Q S'ABBOTTRl OS-ABBOTTRL OS-ABBOTTS OS-ABBOTTS ....... OS-ANDERSONCD | ...... | OS-ATKINSONJ2 03-A TK IN S0N J2 O S -A 7K IN S 0N M 0S-8AKERH ' OS-HOPKINSKE OS-HOBNBECKJW OS-MORRISONM OS-NICHOLSONDH | OS-PARKEFUL ......... OS-SHEPHERDM O S-W ESTB RO O K LM OS-SEEBAUGHR O S -N IC H Q LS 0N D H 2 sam ple Date 12/1 0 0 1 4/11/2002 12/12/2001 4 /1 1 /2 0 12/13/2001 1/9/2002 4/12/2002 12/12/2001 12/14/2001 12/11/2001 12/13/2001 2/4/2002 12/11/2001 12/10/2001 2/4/2002 12/12/2001 2/26/2002 2/4/2002 u g /l 0.0606 NQ (0.050) 0.22 0.422 ND (0.010) 0.149 0,264 ND (0.010) 0.339 NQ (<OJ050) ND (o.oio ) ND (0.010) 0 .0 5 0.177 NQ (<0.050 ND (0.010 0.273 0.242 com m ents Drinking W ater Drinking W ater Drinking Water DrWdnn W ater Drinking w ater Drinking w ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking W ater Drinking Water Drinking W ater Drinking W ater Drinking w ater Drinking Water 0S -A T K IN S O N J1 OS-BAKERHK2 OS-CHANEYQ OS-COBBAJ OS-COBBAJ2 O O D A V IS A 2 O O B R IE N E R D 1 OS-GROSED 0S -H A R R IS R 1 OS-HQFMANNDE O S -ttO P E W E lG OS-JONESOR OOKAUFMANC OS-LOBBIN& 03-R O B E RTSDR 1/9/2002 2/20/2002 2/14/2002 12/11/2001 1/15/2002 2/13/2002 2/5/2002 2/15/2002 12/12/2001 12/12/2001 1/26/2002 12/13/2001 1/11/2002 2/12/2002 1/11/2002 ND (0.010) NQ (<0.050 0.164 0.0639 ND (0,010 l NQ (<0.050 .... ND (0.010) ND (0.010] 0.354 ND (0.010] 0.0614 ND (0.010 0.076 ND (0.010 . Mlsc. Unused Unused Mlsc. Unused Unused Mlsc. . Unused Unused Unused Unused Mlsc. Unused Unused Unused * Drinking W ater (hlghllghtodinbold blue) Indicates human consumption. Non-drinking W ater uses include livestock watering, gardening and any other non-human consumpBen water uses. ND Not Detected a t or above the limit of detection (LOD). The listed LOD Is approximate and varies by Instrument and over tim e. . N O a Not Quantifiable. Detected at a level above the LOD and below the limit of quantification (LOQ). m 0 8 results are reported In ugA. Mtec. = Miscellaneous water use Is not used for drinking. D ate highlighted In yellow are results for water sources located rt the one-mile radius that were resampled during the two-mlle radius sampling event beropie TVW W ei W ell W ei WeU W ell W ei W ei W ei We! w et W ei W ei W ell Wel w ei wen Sprint Cisterr W ell W ell W ell w ei) W ell wen w ell w5 W eil W ell W ell W ell W ell Well W ell 1/29/2003 4:18 PM lof2 Tab 6,1 Consent Order TSFjdS] A S B 0 2 i? 4 6 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 Mile Radius) Lubeek, wv Sam ple ID O S -S H E P H E R D P O S -V A N D Y N E H R O S -V A N D Y N E H R 0 S -V A N D Y N E H R 1 OS-W HITEEE OS-W IGALR 0S-W IG ALR1A 08-W lG A LC A OS-W INTERSJ O O W R I6 H U E d u po n t b re DUPONT DR3 ..... sam ple Date 12/14/2001 18/13/2001 12/13/2001 1/11/2002 2/20/2002 1/14/2002 1/26/2002 4/3/2002 12/11/2001 4/23/2002 1/2 /2 0 0 2 1/2/2002 -.......... U4> u g /l NQ (<0.050) ND (0.010) ND (0.010) 0.634 NQ (<0.050) NQ (<0.060) 0.127 NQ (<0.05) 0.166 0.839 0.68 W ater U s e --------Com m em s Mise. Unused duplicate Unused unused Unused Unused Unused MISC, unused Unused Unused saropw j W eil W all W eil Welt W ell W elt W ell W ell W et W ail W ell W eil O S -A TK IN S O N J3 OS-CAM PQ3 OS-CAM PG2 . OS-DOW L6RB2 OS-DOW LERE2 O S -R H O D E S R O S-S86A U SH V 0S -T E N N A N T JD 0S-CAM PG1 OS-DALEL O S -D A V IS A 1 0 3-D 0 W U R E 1 DUPONT DR3A 0S-G R IEN ERD 2 QS-H O PEW ELL1 Q S -M O Y E R S V 4/12/2002 k o /2 0 0 2 2/20/2002 1/28/2002 1/20/2002 2/4/2002 2/26/2002 2/8/2002 2/28/2002 2/28/2002 2/8 /2 0 0 2 1/28/2002 1/28/2002 2/5/2002 1/11/2002 2/28/2002 0.625 0.0998 0.081 0.347 0.35 0.0748 0.278 0.1D7 Non-drinking water W ater Catbe W ater C arte W ater Cattle dupltcata M is t. W ater Cattle Unused Unused 0.338 0,54 0.446 0.307 0.175 0.409 0.743 0.974 MISC. Mlsc. Unused Misc. Unused Misc. Unused Unused Spiinc Sprint Spring Spring Spring S p riM Spring Spinp Cistern Cistern Cistern cistern a s te rn a s te rn Cistern Cistern * Drinking w a te r (highlighted in bold blue) indicate? human consumption. Non-drinking W ater uses Include livestock watering, gardening and any other non-human consumption water uses. ND = Not Detected a t or above the lim it of detection (LC D ). The listed LQD is approximate and varies by Instrument and over fime. NQ = Not Quantifiable- Detected at a level above tee LCD and below the limit of quantification (LOQ). All 0 8 results are reported in ug/l. Misc, = Miscellaneous w ater use is not used tor drinking. 1/29/2003 4:18 PM 2of 2 Tab 6.1 Consent Order T&F.xIs] ASH021747 E D 639979 T ab le 6.2 M on ito ring W elt C o n stru ctio n a n d G ro u n d w ater E lev atio n D ata Dry R un L andfill L ubeck, WV Monitoring Wells Zone Overburden AZone . Parameters Measuring Point Elevation (feet) Total Depth (feet) Well Diameter [inches) Slot Size (Inches) Screen Length (feet) Screen Interval (feet) ................. pecember-01 January-02 February-02 March-02 May-02 August-02 October-02 DRMW-6A DRMW-12A DRMW-12B DRMW-13A PRMW-21A DRMW-16B DRMW-17B 744.46 11.89 2 0,010 737.B1 738.29 738.28 738.75 738.25 735.61 736.92 732.41 17.17 732.85 20.24 722.57 13,33 707.62 19.79 44 4 2 0,010 0.010 0,010 0.010 5 720.24715.24 727.30 728.50 727.99 728.09 725.97 725.51 725.91 10 722.61 712.81 5 714.24709.24 10 697.83687.83 Groundwater Elevation (feet) 728.11 729.14 728.70 729.58 729.67 728.24 714.35 716.97 714.16 716.68 716.70 713.62 - - - - - 726.64 713.97 703.00 792.98 61,61 4 0.010 20 751.37731.57 - - - - 736.49 853.56 127.09 4 0.010 20 746.47726.47 * - - 737,19 DRMW-1BB 925.87 202.05 4 0.010 20 743.82723,82 e- . - 757,47 Monitoring Wells . Zona . . A Zenefeon't) B-Zone Parameters Measuring Point Elevation (feet) DRMW-19B DRMW-20B DRMW-12 881.99 868.79 733.1 DRMW-13 722.68 C-Zone AboveA Zone DRMW-15 DRMW-21B DRMW-14 734.28 707.67 838.03 Total Depth (feet) Well Diameter (Inches) Slot Size (Inches) Screen Length (feed Screen Interval (feet) 151.76 4 0.010 20 750.23730.23 136.41 37.82 37.54 48.60 44 4 2 0.010 0.010 0,010 0.010 20 752.38 - 732.38 15 710.28 695.28 15 700.14685.14 20 .. 7 0 5 ,6 8 - 685.68 Groundwater Elevation (feet) 177.20 4 0.010 20 550.47530.47 239.91 10 NA NA NA December-Ol January-02 Februaty*02 March-02 May-02 August-02 October-02 _ - - - 750.94 - - - 752.95 724.40 725.25 725.40 725.74 725.99 723.65 723.54 711.81 712.17 711.46 712-21 712.54 710.65 711.65 716.10 710,50 716.33 717,02 716.88 715.82 716.02 _ - 613.01 754.09 757.99 754.87 755.45 755.12 755.31 755.13 1/29/2003 l o f i Tab 6.2 Consent Order T&F.xb &SH02748 1 ID 6 3 9 9 8 0 Table 6-3 Summary of Analytical Results: C-8 in Groundwater Dry Run Landfill Lubeck, WV S am ple i D ate | C*8 (ug/l) O verburden DRMW-6A 10/9/2002 8/28/2002 6/22/2002 3/30/2002 2/20/2002 1/27/2002 12/12/2001 7 /2 0 /2 0 0 0 7/21/1999 5/26/1998 7/22/1997 4/10/1996 1.13 0,785 1.24 0.843 0.822 0.824 1.04 0.212 0.098 0,27 0.36 0.19 _ DRMW-12A 1 10/9/2002 8/28/2002 5122/2002 3/3Q /2002 2/20/2002 1/25/2002 12/12/2001 7/19/2000 7/21/1999 5/28/1998 7/22/1997 4/10/1996 0.181 0.088 0.0832 0.078B 0.125 0.16B 0.158 0.128 0.081 J <0.10 <0.1 <0.1 1 DRMW-12B 10/9/2002 10/9/02 (duo) 8/28/2002 6/22/2002 3/30/2002 3/30/02 (dup) 2/20/2002 1/25/2002 1/25/02 (dup) 12/12/2001 7/20/2000 7/21/1999 6/16/1998 0.258 0.242 NQ NQ NQ NQ NQ 0.073 0.085 0,215 ND (0.029) 5.4 <0,1 1/29/2003 1 of 3 Tab 6.3 C onsent O rder T&F.xIs A SH 02X 749 EID639981 Tab! 6.3 Summary of Analytical Results: C*8 in Groundwater Dry Run Landfill Lubeck, WV S am ple 1' ' 1 b at O verburden 1 .. ...... DRMW-13A 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 5/26/1998 7/22/1997 4/10/1996 4/10/1996 (dup) ------ ..... ...... ........ ,-l_- -- DRMW-21A 10/9/2002 ' .... ....... ........A -Z o n e w e lls DRMW-16B DRMW-17B DRMW-18B DRMW-19B DRMW-20B 10/8/2002 10/8/2002 10/7/2002 10/7/2002 ........ 10/8/2002 A b o ve A -Z o n e W e ils DRMW-14 10/15/2002 8/28/2002 5/22/2002 3/30/2002 2/20/2002 1/27/202 12/12/2001 7/20/2000 7/21/1999 6/16/1998 7/21/1997 4/10/199 -- -------------- ----------- B -Z one W elte DRMW-12 10/9/2002 8/28/2002 5/22/2002 3/30/2002 2/20/2002 ________ 6.68 _____________ 5.14 2.31 4 3.73 5.97 6.4 9.9 0.070 J 8.7 15 8 .2 11 0.27 NQ (<0.05) 0.155 N D (<0.01) NQ (<0.05> NQ (<0.05) NQ (0 .0 5 ) 1 1 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 .1 ......... 1/29/2003 2 Of 3 Tab 6.3 C onsent O rder T&F.xls A SH 021750 EID639982 Table 6.3 Summary of Analytical Results; G-8 In Groundwater Dry Run Landfill Lubeck, WV .............. . S am p le T1 D ate C -8 (u g /l) ................................ DRMW-13 DRMW-13 (Cont.) B -Z o na W e lls (C o n i) 1/25/2002 12/12/2001 7/19/2000 7/21/1999 5/26/1998 7/22/1997 4/10/1996 10/9/2002 8/28/2002 8/28/02 (d ue)* 5/22/2002 3/30/2002 2/20/2002 1/25/2002 12/12/2001 7/20/2000 7/21/1999 5/26/1998 7/22/1997 0 .1 1 6 0 .0 8 6 0 .1 6 0 .1 3 4 < 0 .1 0 <0.1 <0.1 2 0 .9 13.1 14.6 16.9 12.6 11.5 16.5 9.86 9 .8 3 .6 9 .2 7 DRMW'15 " B -Z o n e W e lls 10/15/2002 8/28/2002 5/22/2002 5/22/02 (duD>* 3/30/2002 2/20/2002 1/27/2002 12/12/2001 7/20/2000 7/21/1999 C -Z o n o W e lls ........ 4 .9 2 3 .9 9 5 4 .6 6 4.91 3.6B 4 .3 5 4 .9 4 0.763 0.263 DRMW-21B I 10/9/2002 1 NQ (<0.05) N D 13Not D etected a t or ab o v e the limit of detection (LOD). The listed LOD is approxim ate and varies by instrum ent and over tim e. NQ = Not Q uantifiable. D etected s quantification (LOQ). J = estim ated value (below laboratory quantitation limit). Note: Analytical m ethod changed a s of N ovem ber 2001 (se e Section 2 .0 of DuPont (2003b) for details). *Analytical duplicates' values w ere previously Inadvertently om itted from the tables. 1/29/2003 3 of 3 Tab 6.3 C onsent O rder T&F.xls SH2A751 BID639983 Tabl 6.4 Sum m ary o f A nalytical Rsulta: G*8 in S u r fa c e W ater Dry Run Landfill Lubeck, WV " Sam el# OUTLET 001 OUTLET 003 OUTLET 004 ....... - D ato 11/21/22 10/30/2002 9/30/2002 . 8/30/2002 7/31/2002 7/1/2002 6/28/2002 5/28/2002 4/24/2002 3/25/2002 2/25/2002 1/28/2002 12/12/2001 10/3/2000 12/29/1999 5/19/1998 ...... 4/9/1996 11/30/2002 10/30/2002 9/30/2002 8/30/2002 7/1/2002 6/28/2002 5/28/2002 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 6/28/2002 5/28/2002 4/27/2002 3/26/2002 2/25/2002 1/28/2002 12/12/2001 ' G-8 lug/l) 64.6 81.7 Noflow conditions No-flow conditions No-flow conditions Noflow conditions No-flow conditions 30.9 41 71.6 43.9 41.6 Noftow conditions 31.5 66 17 86 No-flow conditions No-flow conditions No-flow conditions Nottow conditions 25.3 No-flow conditions No-flow conditions 20.1 6.77 No-flow conditions No-flow conditions 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 158 No-flow conditions No-flow conditions No-ftow conditions . 1/29/2003 1 of 3 Tab 6.4 Consent Order T&F-xIs A SH 021752 ED639984 Table 6.4 Sum m ary o f A nalytical R esults: C-8 in S urface W ater Dry Run Landfill Lubeck, WV Sam el PROPERTY BOUNDARY STREAM SAMPLING POlNT#1 (SS-1) STREAM SAMPLING POINT#2 (SS-2) D ale 10/30/2002 8/30/2002 5/28/2002 4/24/2002 3/25/2002 2/25/2002 18/2002 12/12/2001 16/3/2000 12/29/1999 7/14/1998 4/9/1996 10/30/2002 8/30/2002 5/28/2002 4/24/2002 3/25/2002 2/25/2002 1/28/2002 12/12/2001 10/3/2000 12/29/1999 6/19/1998 10/30/2002 8/20/2002 5/28/2002 4/24/2002 3/25/2002 2/25/2002 1/28/2002 12/12/2001 10/3/2000 12/29/1999 5/19/1998 - C -8 iUM/l) 3.8 No-flow conditions 9.41 6.69 22.8 3.81 11.1 3.99 10.3 39 0.88 9.9 1,63 No*f!ow conditions 1.63 0.932 1.06 0.85 0.893 1.19 0.758 0.54 1 29,2 Nb-flow conditions 51 28.9 66.6 24.3 42.4 20.5 27,6 87 4.6 1/29/2003 2 Of 3 Tab 6.4 Consent Order T&F.xIs A SH 021753 EID639985 Table 6.4 Sum m ary o f A nalytical R esults: C-B In S u r fa c e W ater Dry Run Landfill Lubeck, WV Sariiole ... DR LEACHATE POND UNDERDRAIN for details). D ate 10/30/2002 5/28/2002 4/24/2002 3/25/2002 2/25/2002 1/28/2002 12/12/2001 10/3/2000 12/29/1999 5/19/1998 7/22/1997 10/30/2002 5/28/2002 4/24/2002 3/25/2002 2/25/2002 1/28/2002 12/12/2001 C -8lua/B 704 160 237 334 266 398 109 27,4 34 56 62 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 EID639986 T a b le 6.5 Sum m ary o f O n -slte a n d O ff-site E x p o su re P a th w a y s E valuation Dry R u n Landfill Lubeck, WV Pathway Assassinant {Complete or Comparison to Screening Pathway A ssessm ent Complete or Comparison to Screening Criteria* ASH 021755 WH o 2 /4 /2 0 0 3 1of 1 T ab 6:5 C o n sen t O rder T&F.xts I FIGURES ASH021756 O H W / LETART LANDFILL WASHINGTON WORKS FACILITY/ LOCAL LANDFILL DRY RUNJ-ANDFILL lie!phi ($ :JSF pile ici.u> ljr >N i j F0 r ' f ^ j a C ^ G & r 1-------- - ^ v ^ e r t o w j j 'ife s v ifK - g g m it^ w ' ^ r c 4 - - v a^ '3 I bf w .r ---- - 't 'r r T f o n . r j ^ l t a l o s | ^ Vi nna ?S0 'v , - *i, / -(?1 ^-- Sp^iysboro-"' Harr isv.iSle $ zL "'- `Wetlsjteri' ^--^>arr|SOftvi/ `tiBeHe 35W --? ^ '................ ^ w ^ Ja cieso it; - 1 'S r V " IS ,, S tfc rJ ie * jrd - v { t f fR A vS ^W O iM U t j S ( *> * Si Cr s Mi t t'laAgf f^llpltLf \k 11D<SifS"T s ng C\ /} , *; &Y-4 A ;w w ' \ . \ ^e0 ;jplzabetrr -cS..m. _ithvH^l.e caxs i /s ,.'7'* -w l ". / \ 'f' Tanner />&, > V .'/T y - \ >* ~xtewiti ; > / yawinpt^wn,/ \i t h ' /Wayne \ f k l , " ,1 For/ DWtfesiiie x lS 2 . ? ^^aj nd'epeLvoioi\lneeyLv">io{rlem/c/AaicsP5.,,a5w.a^^^0. .ge- w <rrTe // 42?-A- rabia W in ,F u rn ace. j^R oberfsir^g' . -1 .___ ^waiton-^ D uPont W ashington Works P roperties Corporate Remediation Group DvPAeitntXlfniedncCrAS*T&f '* DuPont Washington Works W ashington. West Virginia ASH021757 EID63999Q E D 639991 LEGEND; 10.0+ ug/L 1.0-10.0 ug/L 0.05-1.0 ug/L <0.05 ug/L ffl O N tn M f ASH021760 p 5* a | Ap t lg i* h l HH < 2 2i . s r o en i *! liM J 0 1 ^i 1 1 i EJ 5 D Z gsO2e _a(. 3ofO-e ID S_ UJ I 1 CD t V 8 ASH02176X EID639993 (OAULXORAV--PWWEOUtl-W B etas (-P4O6+,6-M00W32 -ia7o,742-M0 wRooia_i, ' ` [ . -0 ^ LEGEND - MONITORING WELL & = PRODUCTION WELL 1 CINONGCREONUTNRDAWTAIOTNEROF C-S <ug/L) M Ho(Ti SH021762 SCALE 700. 700* > t 0 -8 IN 'GROUNDWATER - 4002 &mpm. Corpora Rsrmdhtian 4M^Uiane* hhww * -W eiewM 'DuPont Washington Work Fcety * Wahfogtont,.Wrt Virginia ",/r"! 'CtWSartpy UHI P & sb. BuBdfe 37 ASB021763 EID639995 EID639996 3 ASH021765 E ID 639997 IID 639998 > E D 639999 ASB02760 EID640000 I ,y EID640O01 WEST VIRGINIA stAte ao* _i= WTM?wo' LESEND: UJBEGK {0333*110 MBPUSUO WATER SUPPLY w o ranse HVEH TRAIAEN)SECT OHO H VER W A TfflS A M P O 3 tOCATJON AND 0-8 CONCS0RAHON3 w Q HANGE Noie ND I<OOf Us/L NQ > XUH <US5 US/L ---------------------------- p ...... ...... |.. ---------------------------- ---------------PT--------------- a "5 [ _ -- m ewanwniow <ao wws od CH 0SM B R B B W B OwycrrtsiDMiOflimaw OtPoat WosMajtoa Wortes FecStty wwagrees* uni Otte - WMt Virginia rz EID640002  tk'PV'v.' ' ' .f v. - ; - :1V, .';; . '. %' : ;v;.'3 - 0 Remote User Remote User Job 184 07/16/04 10:30 AM EID640003 SS (v> J -I H ILLUSTRATIONS TAKEN FROH SIMARD, 1989. N orth A P 'JE S re C B iE T C R R A C D E H O L O C E N E FLOODPLAIN U T T U E HOCKING WATS? ASSOCIATION OHIO OHIO RIVER HOLOCENE FLOODPLAIN rS r S o u th A' PLEISTOCENETERRACE DUPONT WASHINGTON WORKS W EST VIRGNIA rlttfw K W Sti CfVATON (Mt B E D R O C K (DUNKARD GROUP) VERTICALSCAIIEXAGGERATION AT 1:9 LEG EM : m H O L D ^C E N E O V E R S A N K S 1 L T A .N O C L j A V D E P O S IT S - PUBS-- T O C E N E G L A C IA L . OUTW ASH DEPOSITS COURSE SAND A N D GRAVEL li R H V O V R K E D P L E I S T O C E N E A L L U V I U M SA N ' A N D G R A V E L . mo w H (0 HORIZONTAL S O IE E ID 640004 EID640005 LEGEND MONITORING WELL. PRODUCTION WELL OUTFALL SAMPUNG POINT CROSS SECTION UNE o M -4 Mi W SCALE Kim, '531.............."j s------ j -------- <> ' ^ C ap oMtt4MijURuKMemswBwKSiFiiJamNtmlHomn*Osa? UH BertW3*. 2? CROSS--SECTION LOCATION MAP BuPwit WuKfafftait WertesMeinWant Washington, Hast SfagWa ----er-- A SH 021774 BID64006 South EX D 640007 240 FT l0ENS; EM; -- OU laaiai nil I-- 1 Sates* - S M ^ O S P BTRl Silt - U1 PB71 Sone=d and Grovat -- SW.GfViW.tiM n,, K B Peat n ESS3 Bttdnodc EZ3 ay~ W SWIe WoUr I m * t e e 1961 -I-- e-to ste Cwtoat Stella Wet U v tl Inlanad ...... .% . G re u n d -a q le F H w r t f r a e t b n . ? = ---- nil 6 1 CROSS-SECTION 8 -B' 'tSa... .-.-rviicm-i- Corpora* RanwaeUon Ororn ouPavtWMkk.sK. ** M<;no1- 4< m w M w m WoshShigton, W**lVirgWa 'S S C S L H iE fe S " -- " /M. M W >! >1 Holocene Age Pleistocene Age Glacial Ouiwash Deposits Permian Age [Washington Fnv : >: : - ." o -- : : - - 'o ;' P - - x " `' V-'.b' ? P:'0;-c>'.:0 oS`-/0'-c>':. /Q-'c)' ^ :u ` U-i'P: : \w XfT lllllllllll - - p;- ` r- e -.. c-'.ciPere* oo.-o-fi .''o-'-'rv '-S. -'0 ;.>1 | S ^ .O-Q-ro- OQ-: -^ - '9 )' -, ^ ,j- : . .. -'o --': : .-'p;'- : b->-o-Q-:'i>- . ?; . - -'<v- 0 -OCv'-.'oo-. i "O;-'e>- 0 0;.';-' '^-O M0-v- .-y- J* |5 I II* 1 it Hll A (L g ii C OL tn 9U (ISW W ) NOIIVA313 "u 1I SO 100 ASB021776 EID640008 N o rth D S2 0 20 FTn RBLMW--9 S --2 9 Z07-MW1 (TW-22) 9GHW-2 B -38 SM :/,o . & > ', ;o',o: .CS;. : $ / c v . v , o '. R . .'.o '.:P .;:o ' : i.O ; .'C J * /#,A v;b> o'.o; ;o!.<p: :'ci'Vj:V*-, *;0V'.d:'', ;o*'s>:''. ;efd:;.m'. .:.*Ki:;'.:q'>3t*'rt,;qi'\.<Al5*:,">ft.:<?J<-t?'':it*-'?`.<C?iV;fV*'?,*? I ' : o \ c > : He?;.-'. vcs.- , t.c--pv;'.\ ' - o '^ : ';o''.<Jj?e:i:';''.. A l.'it*.'' uj J&nfi . t4 off; h-<?h :'b,<^ ' :G- ty :Q';,'b'.:; v ' ;q\o:';. iq'-o:';'. :q-,d;;',iq'^rhq'i?:.-', 'q'^:;'. :q'<p:;'.;q;.<?;: , :q`g?;::q <?.-:?<=?^.-vP-;-, r V y .' -'.(K' '.ri' ;ri >''iv >* r~t ' n' ,fY -'pt*Y TS*n* 'b '1~ EID640009 RHIfi T c s p e o f l -- O L o S w n d - S M .S C .S P E 3 S cran d a n t* G ro v 1 -- irrm s a t - m l S W ,G P ,G W ,G W LEGEND; S 3 PftO t - PT f^ T rl Bedrock .. S ta tic W rt*r U vJ, Dec. t9$1 A pproxim ate Geologic Ccota c t S ta tic V o te r Level, Inferred m ao y -a C roundw flter Flow D irection -= fe : ao NH> >1 vl MM: ni MtfJNMMMt BootyWPn>. toof-saia 8T20H Sftr Nort_h ans JyT7. 'A 'Q -\:-X - . . . . O '* .* , vQ,.'-; Q- '.y &. ELJEVATION. (feet MSL) J :v ;:,-a v .r g o: P-~ 'q- :4 b --?> :o ?o ;'- i* fr l9*f H Is f fBa is- p - p P P b P : : - ;&.<?v ? ? :'&`Q'--<=rQ'O''P 'f\ y: . ---ir -JV-`: -' `: -0-'y& '-h:W - > .- -' - `.'.'o'. .-; '"cvk---t4o- *;-O---. O-;<V. rf.'.-'O 0;.o -o. -: -*04,v/*7fWy* . ' -v i-TM.i' -,-<X(Vn. . a * - - . e V / * :Pt;0?. -|n "' i ip-:6 V o - ;A-: - ."o"-,, . - * . _ft f-A `O . * V.* .-'Ozi - sv - 0 - -A,';p y q 'M P d `ri'- - * I ' ? *r :.*'51 : ;.`cloP -P to -.: : M fe .;- -0-0-p :-Ai'.'-b /r-b P -PP-o-PQo-i: o 'S ' -V-b:'-~Pb:&-ri''??'-:.:U v i;.tv .ia.`V K 'n- 0--' //-P-O-0- JCUJ yo^uiqnPM, o6y MWJqJ stisodeq t|SDM^np |opo|3 sy suaoo^sisjd f P tP t= = rxm r B ................................................- SCALE S05-M W 02 OHIO RIVER (NORMAL POOL E L E V A H Q N = 582.Q ') 630 614 -598 582 566 LEGEND: HOLOCENE OVERBANK DEPOSITS SILT AND OLAY PLEISTOCENE GLACIAL OUTWASH DEPOSITS COARSE SAND AND GRAVEL HORIZONTAL SCALE: VERTICAL SCALE 1"=*20' ('UUHUsUl*b . . 4VVi Corporalj|yiBffl*omnHabMtiMWlloa Group JO uPm t m d tm s M m o n d Bfcrtta&mvgMte*JntPtBoaOtofwBouracf1lng8D257 SECTION G--G* DuPont Washington Works Washington, West Virginia A*the** /V92 IdMH9U rwnDEL JW5B00I SH021780 EID640012 E ID 640013 I :oNKsJ CD LEGEND A m o n w o r in g w e l l AVPMI - PROD A C T I O N W E L L ------ APfW OXfMATE GROUNDWATER PLOWDKECHOM ....-- ...- . CRCU N O W A T E R E L E V A T IO N CONTOUR REVISED - FEBRUARY 2 0 0 2 num inaK A T E R EtEVAilON HAP OuPontWallnttonW M*pl""< WnahniTton, Wait ASl^nl S e w * M $ $ L U V H o cV in g , Q u a d r a ijjls " W *a t V lr fi mm> ^ 3 BWonrMlsyftQMlQBQP iPe ezloo,wBuffcii9O50t5t BVtQ /V 7 /0 \ ii m p tftttB u . H cuxw r DB. T fetM O t 1 " 4 I ASH02X782 EID640014 MCROM#883 EID640015  oU NH -J E ID 640016 STATIC WATER LEVEL OCTOBER 2002 W H<n 2 ta 2HCO 5wa H-4CO EID640019 ooso- 500J oa H04 *] t F liF K in SHALE SILT SAM C A S TO N E AND S =H _TS TO N E ---- ;------ ------------------ mm 550 500 C LA Y , WEATHERED a A L AND WEATHERED SANDSTONE SCREENED INTERVAL X STA TIC WATER LEVEL OCTOBER 2002 , SCALE M MM CALV E S V E X A G G E R A T IO N : S X <glB>' 1 "-SS3T ^ C a p o n i R o m ed iiS o n i S o p in ** * Scrir m * M ta j g e o l o g ic a l c r o s s - s e c t io n c - c - ie c o l U ndSfl o rfte g to n , W M t-W fW o t'j^ rr . * ?_ (ELEVATION IN EEET) t a # mottm 1 A SH 021788 EI0640020 ASB021789 EID640Q2X : i! ) j I i ' - ASH02179O EID640022 A SB021791 53ID 640023 A SH 021792 ID 640024 LEGEND: ` , SURFACE WATER SAMPLE LOCATION SCALE 650 650' Mutt ltfwemum) ngtnawahawlwis A SH 021793 EID640025 LGND SCALE 650 0. 650' Corporate Renieiflation Groi*> A n AlKtmca bwtuMirm P iiP m t and VHS Diamond Sorlfly Mill PiOlOr Building 2 7 yitnlrtgten, Pelowcre 1980 Ustori Landfill SU9 Letort, W est Virginla I I (MEf1a/3>60/9e90 11kwurt "" "an. rnuoto 1 TW. * * M 1 SH021794 EID640026 .KU*** XXXuuUfnfW--h---**>i* A<Wrb5w2Sl0Ni*oC*MHMeOnMWWef*!fKWMt**WE*bU**i>-1."- yWnwKgttS* cftss-sEcmpH tnoNmap L^ort. wto~n*fVttirtghtei* ASB021795 1ID640027 I XI 8 ilS .il* 5 3 I. i! _! i . Li t- o-otoci unit. WTtB*b. * not no" oo o NORTH A SH 021796 EID640028 E ID 640029 a o NH5 0 <0 J EID640030 IU-2A A SH 021799 EID640031  S H oaieoo EID640032 SHO2X801 EID64Q033 ASH021802 BID640034 A SH 021803 EID640035 ASH021804 EID640036 uot ca H Ci O ED640037 r o M H CoO 0) E ID 640038 j S oS NH O O EID640Q 39 northwest ASH021808 EID64040 I ASH0218X EID640042 EID640043