An Overview of Environmental Investigations

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An Overview of Environmental Investigations
January 22, 2002 Presented by DuPont Corporate
Remediation Group
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Todays meeting...

• Provide an overview of the basic objectives,
  strategy, and techniques for conducting an
  environmental investigation.

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DuPonts 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.

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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.

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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.

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Basic Environmental Investigation Steps, continued

• Identify appropriate investigation techniques.

• Develop work plan.
• Agency interaction.
• Perform vendor selection and contracting.

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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.

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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.

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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.

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Evaluating Historical Land Use

• Aerial photography.

• Engineering prints.
• Construction and operation details.
• Raw materials.
• Personnel interviews.
• Public files.

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Historical ResearchAugust 23, 1995
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Historical Research March 20, 1947
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Historical Research April 1, 1947
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Historical Research November 30, 1951
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Historical Research November 25, 1968
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March 20, 1947
April 1, 1947
November 30, 1951
November 25, 1968
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Historical Research August 23, 1995
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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.

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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).

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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.

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Agency Interaction

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

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Contracting

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

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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.

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Field Work
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Specialized Equipment
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Seven Pieces of Drilling Equipment Used in 2001
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Track Mounted Auger Drilling
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ATV Core Drilling
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Rotosonic Drilling
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Reverse Circulation Air Rotary Drilling
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Advancing Reverse Circulation Casing
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Mud Rotary Drilling
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Geophysical Logging
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Groundwater Sampling
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Robotic Excavation
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Transportation of wastes to off site disposal
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Containment and Temporary Storage of Drill
Cuttings
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Well Sampling
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Field Delays
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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.

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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.

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Hydrogeologic Review, continued

• Volume of contaminated soil.

• Mass of contaminants in vadose zone (soil).
• Fate and transport.
• Nature of compounds.
• Nature of site.

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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.

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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.

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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.

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Reporting and Agency Review

• WDNR review integral.

• Next phase designed and process repeated.

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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.

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Questions?
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Next Meeting
Date Time Place Subject
March 26, 2002 700 p.m. Northern Great Lakes
Visitors Center Results of the Phase I
Investigation