An Overview of Environmental Investigations

1. An Overview ofEnvironmental Investigations January 22, 2002 Presented by: DuPont Corporate Remediation Group

2. Today’s meeting... Provide an overview of the basic objectives, strategy, and techniques for conducting an environmental investigation.

3. DuPont’s Philosophy Conduct investigations that allow DuPont and the regulatory agency to make informed decisions and take appropriate steps to protect human health and the environment.

4. Environmental Investigations • Address multiple needs. • Human and ecological exposure via • Groundwater. • Soil and/or sediment. • Surface water. • Air. • Usually an iterative approach. • Vary in complexity.

5. Basic Environmental Investigation Steps • Research historical land use, specifically detailed operations, spills, etc. • Develop analytical program. • Identify chemicals of concern (COCs) and appropriate analytical methods.

6. Basic Environmental Investigation Steps, continued • Identify appropriate investigation techniques. • Develop work plan. • Agency interaction. • Perform vendor selection and contracting.

7. Basic Environmental Investigation Steps, continued • Mobilize and set-up field operations. • Sample potentially impacted media (air, soil, sediment, groundwater, and surface water). • Review analytical data for usability. • Perform hydrogeologic review.

8. Basic Environmental Investigation Steps, continued • Evaluate media-specific characteristics. • Types of COCs present. • Concentration(s) of COCs at exposure points. • Evaluate results against realistic exposure scenarios for humans and environmental receptors.

9. Basic Environmental Investigation Steps, continued • Evaluate if corrective measures are warranted based on available data. • Fix may be temporary. • Report findings and recommend next steps. • Agency interaction and repeat steps for next phase of investigation, as necessary.

10. Evaluating Historical Land Use • Aerial photography. • Engineering prints. • Construction and operation details. • Raw materials. • Personnel interviews. • Public files.

11. Historical ResearchAugust 23, 1995

12. Historical Research March 20, 1947

13. Historical Research April 1, 1947

14. Historical Research November 30, 1951

15. Historical Research November 25, 1968

16. March 20, 1947 April 1, 1947 November 25, 1968 November 30, 1951

17. Historical Research August 23, 1995

18. Analytical Program Development • Generate potential COC list and select analytical methods. • Identify acceptable analytical laboratory or laboratories. • Develop Quality Assurance Project Plan (QAPP). • Consider time-sensitive samples in schedule. • Shipping issues and lab waste disposal.

19. Identify Investigation Techniques • Consider nature of COCs. • Corrosive, ignitable, flammable, float, sink, sorb to soil, bioaccumulative, toxicity, etc. • Consider COCs and sample device interaction. • Consider site conditions (access, underground obstructions, power lines, and other hazards). • Consider worker health and safety (PPE).

20. Work Plan • Summary guidance document for all work proposed. • Specifies all procedures, techniques and protocols to be employed during investigation. • Uses historical research, interviews with former workers, etc. as guidance. • References QAPP.

21. Agency Interaction • WDNR provides oversight and recommendations. • Integral part of site assessment. • Work plan may be revised based on WDNR input.

22. Contracting • DuPont contracts with all vendors to ensure project work is performed according to the work plan.

23. Mobilization and Sampling • Set-up is integral to a successful field program. • Need offices, communications, etc. • Access issues resolved (clearing, off-road vehicles, etc.). • Field work can range from days to years. • Depends on objectives. • Unforeseen circumstances/conditions. • Weather.

24. Field Work

25. Specialized Equipment

26. Seven Pieces of Drilling Equipment Used in 2001

27. Track Mounted Auger Drilling

28. ATV Core Drilling

29. Rotosonic Drilling

30. Reverse Circulation Air Rotary Drilling

31. Advancing Reverse Circulation Casing

32. Mud Rotary Drilling

33. Geophysical Logging

34. Groundwater Sampling

35. Robotic Excavation

36. Transportation of wastes to off site disposal

37. Containment and Temporary Storage of Drill Cuttings

38. Well Sampling

39. Field Delays

40. Analytical Data Review • Analytical data is the cornerstone of the investigation. • Prelim. results typically provided within 30 to 60 days from receipt by lab. • Based on lab capacity, complexity of analyses, etc. • Third-party review. • Final results. • Project team review can take months.

41. Hydrogeologic Review • Geologic conditions. • Groundwater flow, gradient, and direction. • Extent of contamination in aquifer (vertical and horizontal). • Volume of contaminated groundwater. • Mass of contaminants in aquifer.

42. Hydrogeologic Review, continued • Volume of contaminated soil. • Mass of contaminants in vadose zone (soil). • Fate and transport. • Nature of compounds. • Nature of site.

43. Exposure Evaluation • Identify exposure pathways and scenarios. • Type(s) of potential receptors at locations. • Frequency, duration, etc. • Compare to calculated or agency published health-based guidance. • Conforms to agency guidance. • Identifies potential issues.

44. Corrective Measures • Evaluate exposure pathways that need elimination. • Consider if remedy is to be interim or final. • Consider type of exposure. • Consider size of the exposure area and nature of COCs. • Reference mass, volume calculations made earlier. • Evaluate technologies.

45. Reporting and WDNR Review • Report memorializes efforts and publicly communicates results. • Can be very large (months to prepare and review). • Serves as basis for next phase.

46. Reporting and Agency Review • WDNR review integral. • Next phase designed and process repeated.

47. Summary of Steps • Research historical land use. • Develop/refine analytical program. • Identify appropriate investigation techniques. • Develop work plan. • Agency interaction. • Perform vendor selection and contracting. • Mobilize and set-up field operations. • Sample potentially impacted media. • Review analytical data for usability. • Hydrogeologic review. • Evaluate media-specific characteristics. • Evaluate results against realistic exposure scenarios for humans and environmental receptors. • Evaluate if corrective measures are warranted. • Report findings and recommend next steps. • Agency interaction and repeat steps for next phase of investigation, as necessary.

48. Questions?

49. Next Meeting Date: Time: Place: Subject: March 26, 2002 7:00 p.m. Northern Great Lakes Visitors Center Results of the Phase I Investigation