DuPont Barksdale and Chequamegon Projects Update

1. DuPont Barksdale and Chequamegon Projects Update December 12, 2007 DuPont CRG Great Lakes Visitors Center

2. Purpose of Meeting Barksdale: • Provide an update on site priorities and public commitments. • Provide a summary of site investigation work completed in 2007. • Summarize next steps. Chequamegon-Nicolet National Forest: • Provide an update on site investigation activities at the Cabin Lake and Clover sites. DuPont Barksdale and Chequamegon Projects Update

3. DuPont Representatives Brad Nave – DuPont, Sr. Site Director Jon Hammerberg – URS Corporation, Sr. Project Engineer DuPont Barksdale and Chequamegon Projects Update

4. Former DuPont Barksdale Works Project Update

5. Barksdale Project Priorities Current Priorities: • Identify priority source areas and take appropriateaction. Priorities Addressed: • Evaluate for potential off-site surface water issues and take appropriate action. • Sampling by DuPont and WDNR/EPA has identified no issues. • Continue to provide drinking water that meets appropriate Wisconsin regulatory standards for all site-related compounds to residents with impacted wells. • Develop plan for long-term drinking water supply and implement as appropriate. • All previously affected wells are closed. • No homes in affected area are using local groundwater. • Washburn municipal water supply (completed in 2005) currently supplies homes in affected area. DuPont Barksdale and Chequamegon Projects Update

6. Barksdale Project Priorities Other Commitments: • Fulfill commitments on Home Value Protection Plan. • Ended after construction of municipal water supply. • Continue to work with WDNR. • Continue to be available and communicate with neighbors. DuPont Barksdale and Chequamegon Projects Update

7. Summary of 2007 Barksdale Work

8. Summary of 2007 Barksdale Work Reported Investigation Results • Prepareda Current Conditions Report that: • Summarized all investigation data collected to date (~1998 - 2007). • Established priorities for future investigation work. • Submitted in May 2007. Conducted extensive site investigation that: • Identified over 560 acres as eligible for no further action in 2007. • To date, over 1,400 of the former 1,800 acres of the site have been investigated and are eligible for no further action. • Confirmed that the property formerly owned by DuPont outside of the site fence is unaffected and appropriate for continued residential and recreational use. • Reaffirmed that there are no other affected potable drinking water wells in the vicinity of the site. DuPont Barksdale and Chequamegon Projects Update

9. Summary of 2007 Barksdale Work Continued administrative efforts: • Working with WDNR to request Case Closure of the five Use Areas that comprise 442 acres south of Boyd Creek. • Continue to implement administrative controls in order to reduce the potential for human exposure to site-related compounds on-site. • Continue to support municipal water supply. • Pay Washburn for municipal water system meter fees, water usage, and maintenance. • Address possible electrical grounding issues. DuPont Barksdale and Chequamegon Projects Update

10. Summary of 2007 Work Recovery and Disposal of Residual Site Materials. Evaluation of Remedial Technologies: • Field scale bio-pilot conducted. • Continued laboratory studies at GA Tech. Synthesis of DNX isomers: • SWRI, Inc. DuPont Barksdale and Chequamegon Projects Update

11. Current Conditions Report Summary Site Divided in 61 Use Areas: • Production Areas – 21 areas. • Support Areas – 14 areas. • Waste Areas – 9 areas. • Historically Undeveloped Areas – 16 areas. • Groundwater – treated as a single Use Area. Current Condition of Site: • Primary use of property formerly owned by DuPont is recreational or residential. • Residential property is limited to areas outside of fence that were either historically undeveloped or used for support purposes. DuPont Barksdale and Chequamegon Projects Update

12. Current Conditions Report Summary Priority Ranking of Use Areas: • 33 Use Areas ranked High Priority for further investigation. • 21 Use Areas ranked Low Priority for further investigation. • 7 Use Areas ranked No Further Action. • 5 in the Southern Area • 2 north of Boyd Creek DuPont Barksdale and Chequamegon Projects Update

13. Electrical Grounding • DuPont is addressing possible electrical grounding issues with the municipal water supply pipeline: • Some homes may have been grounded to plumbing as part of original home construction. • This practice is outdated according to current electrical code. • With connection to municipal supply, ground may have been interrupted. • DuPont will have licensed electrical contractor check each home connected to municipal water system. • If the home is improperly grounded due to DuPont’s work, grounding will be addressed. DuPont Barksdale and Chequamegon Projects Update

14. 2007 Site Investigation Work

15. Overview 2007Site Investigation Activities: • Geophysical surveying • Soil sampling and trenching in former production areas • Discrete soil sampling at biased locations • Grid sampling generally in non-manufacturing areas • FIDO Surveying DuPont Barksdale and Chequamegon Projects Update

16. 2007 Investigation Priorities DuPont Barksdale and Chequamegon Projects Update

17. DuPont Barksdale and Chequamegon Projects Update

18. Clearing Work Sites • Cleared: • Four miles of new trails. • X-acres of sample sites. DuPont Barksdale and Chequamegon Projects Update

19. Screening with Geophysics (EM61) • Used to: • Map metallic debris. • Locate metallic pipe lines. • Locate utility lines. • Identify changes in soil conductivity. DuPont Barksdale and Chequamegon Projects Update

20. Geophysics EM61 Results— PAI DuPont Barksdale and Chequamegon Projects Update

21. Trench Investigation • Used to: • Verify geophysical detections. • Locate & sample non-metallic pipes. • Locate & sample foundations. • Recover buried TNT. • Profile process ditches. DuPont Barksdale and Chequamegon Projects Update

22. Trench Sampling at Foundations DuPont Barksdale and Chequamegon Projects Update

23. Trench Sampling at Foundations DuPont Barksdale and Chequamegon Projects Update

24. Recovering TNT fromCatch Box Total of 1,920 pounds of soil and TNT recovered and disposed in 2007 (contained 470 pounds of TNT ). DuPont Barksdale and Chequamegon Projects Update

25. TNX Profiling Product Residues in Ditch DuPont Barksdale and Chequamegon Projects Update

26. FIDO Analysis Equipment DuPont Barksdale and Chequamegon Projects Update

27. Screening with Vacuum Cartridges • Used to: • Compare relative TNT/DNT strength between site areas. • Locate visibly obscured TNT pieces in tall grass and in debris piles. • Locate TNT impacted soil. • Identify large buried TNT deposits. • Screen excavated soil for live loading. • Screen borehole samples to select sample depths. DuPont Barksdale and Chequamegon Projects Update

28. TNT Located Using Cartridges and FIDO TNT found by FIDO visible only after tall grass & sheet metal hiding it was removed. DuPont Barksdale and Chequamegon Projects Update

29. Drilling and Soil Sampling DuPont Barksdale and Chequamegon Projects Update

30. Soil Samples DuPont Barksdale and Chequamegon Projects Update

31. Removing Asbestos 250-lf of exposed pipe insulation was removed. DuPont Barksdale and Chequamegon Projects Update

32. Waste Water Treatment and Disposal • 2,500 gallons removed in 2007. DuPont Barksdale and Chequamegon Projects Update

33. Debris and Scrap Metal Recovery DuPont Barksdale and Chequamegon Projects Update

34. Debris and Scrap Metal Disposal • Total of 50 cubic yards of scrap removed to date. DuPont Barksdale and Chequamegon Projects Update

35. Off-site Monitoring Project Summary Per agreement with WDNR, wells to the south and southeast of site that are not connected to the municipal water supply are monitored biennially until 2009. • In 2007, 33 wells were sampled. • Second sampling event since installation of municipal water supply. • Samples analyzed for nitroaromatic and nitramine organic compounds. • All sample results continue to be non-detect. • Results reaffirm that there are no other affected potable wells in the vicinity of the site and municipal water is not needed in this area. • Next sampling event will be in 2009. DuPont Barksdale and Chequamegon Projects Update

36. Off-Site Monitoring Results DuPont Barksdale and Chequamegon Projects Update

37. 2007 Administrative Efforts

38. Priority Rankings 2007 DuPont Barksdale and Chequamegon Projects Update

39. Proposed Priority Rankings—2008 DuPont Barksdale and Chequamegon Projects Update

40. Closure Request Request Submittal will Include: • Historical Site Summary. • Verification of Site Zoning. • Analytical Summary of Soil/Sediment/Surface Water and Groundwater Data. • Summary of Historical Groundwater Elevation Data. • Maintenance Plan. • GIS Registry Submittal. DuPont Barksdale and Chequamegon Projects Update

41. Pending Closure Request Area South of Boyd Creek DuPont Barksdale and Chequamegon Projects Update

42. Remedial Technology Evaluation

43. DNT Biodegradation Study

44. DNT Pilot - Background Purpose: • To replicate GA Tech pilot at field scale. Location: • Former Lydol House. Goals: • Determine if DNT concentrations can be reduced in the field by applying key learnings from GA Tech 2006 Pilot. • Evaluate if technology can get DNT concentrations below land use specific criteria. DuPont Barksdale and Chequamegon Projects Update

45. Barksdale Field DNTBio Pilot DuPont Barksdale and Chequamegon Projects Update

46. Project Setup and Challenges Area divided into four 10’ x 20’ cells>: • Cell 1 – control (initial tilling only). • Cell 2 – monthly tilling only. • Cell 3 – monthly tilling and pH adjustment. • Cell 4 – monthly tilling and water addition. Sampling frequency: • DNTs monthly. • pH and field parameters biweekly. Challenges: • Tilling clayey soil to a depth of 2 feet. • Started with a slightly different soil matrix than was used in Georgia Tech pilot. • Higher concentrations of DNX isomers and TNT. • Lower intial concentrations of DNT • Lower intial soil pH (<3.5 to 5 average). DuPont Barksdale and Chequamegon Projects Update

47. Results and Conclusions • Conclusions: • 2,4 DNT and 2,6 DNT appear to be degradeable in the field. • Pilot results suggest achieving land-use specific criteria is possible. • Howard Rotovator is an effective tool for tilling soils to 2 feet. • DNX isomers not readily degradeable. DuPont Barksdale and Chequamegon Projects Update

48. Additional Target Analytes

49. Additional Target Analytes DuPont will include up to 15 new compounds to routine nitroaromatic/nitramine organic laboratory analyses, assuming reliable laboratory standards can be obtained and successful analytical performance studies are conducted. The 15 compounds consist of four DNT and 11 DNX isomers. • DNT isomers identified: • 3,4-DNT • 2,3-DNT • 2,5-DNT • 3,5-DNT • Standards have been located for the 3,4- and 2,3-DNT isomers. DuPont is currently trying to obtain standards for the remaining two isomers. • Eleven DNX isomers have been identified as potentially present. Five have been located and purchased, five more have been synthesized; one more to go. DuPont Barksdale and Chequamegon Projects Update

50. Barksdale Path Forward Continue to investigate high priority areas on-site: • Near-term investigation focus will be high priority areas. • Periodically characterize surface water and sediment in drainages located at the security fence line. • Work with WDNR to administratively close the five Use Areas south of Boyd Creek. • Continue to implement administrative controls in order to reduce the potential for human exposure to site-related compounds. Continue biodegradation studies. • Scale-up in 2008. Continue to sample off site potable wells. Continue to address possible addition of new target analytes. Continue public interaction and water supply commitments. DuPont Barksdale and Chequamegon Projects Update