Former DuPont Barksdale Works Project Update December 14, 2005 Great Lakes Visitors Center DuPont CRG

Former DuPont Barksdale Works Project Update

December 14, 2005Great Lakes Visitors Center

DuPont CRG

December 14, 2005 Former DuPont Barksdale Works 2

DuPont Company Representatives

Brad Nave: Project Director – DuPont Corporate Remediation Group

Cary Pooler: Project Manager – URS Corporation


Purpose of Meeting

Reaffirm site priorities and public commitments, and provide a status update for each.

Provide an update on work completed since the August public meeting.

Project Priorities and Commitments ReviewBrad Nave


Project Priorities

Four Project Priorities:1. Continue to provide drinking water that meets

appropriate Wisconsin regulatory standards for all site-related compounds to residents with impacted wells.

2. Develop plan for long-term drinking water supply and implement as appropriate.

3. Evaluate for potential off-site surface water issues and take appropriate action.

4. Identify priority source areas and take appropriate action.


Project Priorities

Other Commitments:– Continue to work with WDNR in the

investigation/cleanup of site impacts.– Continue to be available and communicate with

neighbors.– Fulfill commitments on Home Value Protection

Plan.


Project Priorities continued…

Priority 4: Identify priority source areas and take appropriate action.

– Site investigation work has been undertaken since 1998.

– Site divided into “northern” and “southern” areas. Northern area: primary location of historical

manufacturing and support operations. Southern area: primary location of historical

product storage operations.


Other Commitmentscontinued…

Home Value Protection Plan – Four properties purchased to date. Two have

been resold. One home removed, but property retained.

– An additional offer made in late September; offer turned down and property sold in October.

– Appraisals and inspections are pending for two properties.


Other Commitmentscontinued…

Home Value Protection Plan (continued)– Home Value Protection Program will remain in

effect until six months after alternative water is available. Availability of the program was the last

calendar day of August 2005 for most residents. Last municipal water hookup was in June 2005.

Barksdale Site InvestigationCary Pooler


Northern Area InvestigationWork Completed to Date

Work undertaken to date in the northern area has included:– Groundwater investigation.– Historical building/process review.– Waste area identification.– Stream diversion.– Debris location/recovery.– Discrete soil sampling.– Excavation of soil adjacent to select former

process and support buildings and select process ditches.


Northern Area InvestigationIssues Identified

Learnings to date include:– Two separate plumes of site-related constituents

in groundwater.– Over 280 historical buildings across site.– 13 waste management areas identified to date.

Two former burning grounds. Remaining areas include empty containers,

building rubble and other debris.– TNT present at surface and at depth at select

building foundations and ditches.



Learnings to date (continued):– Percentage level concentrations of DNT isomers

at select locations across the site.– Bare areas distributed across former

manufacturing areas.– Bare areas in former acid production areas.– Potential asbestos containing material (PACM).– Debris includes empty drums, process vessels,

and a variety of other metallic and non-metallic wastes.

– Perchlorate preliminarily identified in groundwater.


PerchlorateOverview

Perchlorate is both a naturally occurring and manmade anion consisting of chlorine bonded to four oxygen atoms (ClO4

-).


PerchlorateOverview

Why are we looking for perchlorate at Barksdale?– A historical document identified in February of

2005 indicated that the former Barksdale plant manager was corresponding with a chemist in Chile about staffing.

– This letter may indicate a that sodium nitrate from Chile was used for as a raw material for nitric acid production at Barksdale.


PerchlorateOverview

At this time, most naturally occurring sources of perchlorate appear to be geographically limited to arid environments. High natural perchlorate concentrations are found in Chilean caliche and some potash ores.– Sodium nitrate is leached from Chilean caliche to

make fertilizers, among other products. Chilean nitrate derived fertilizers were the

primary fertilizers used in the United States until the 1960s.

– Sodium nitrate (“soda nitre” or “Chilean saltpeter”) was formerly an important raw material for the production of nitric acid in the United States and elsewhere.


PerchlorateOverview

Preliminary results:– Preliminary laboratory results indicate that

concentrations in groundwater surrounding the former nitric acid production area range between 0.033 to 150 parts per billion (ppb).

– Perchlorate was not detected in the two potable wells sampled on-site.


PerchlorateOverview

EPA has established a 24.5 ppb limit in drinking water for perchlorate.– Perchlorate inhibits iodide uptake.

Next steps:– Sample additional wells on-site in Spring 2006.


Northern Area InvestigationHistorical Buildings/Ditches



Trenching Investigation– Investigation of subsurface residual product

distribution and identification of former subsurface pit and drain locations.

– Phase I – Identify typical conditions Used remote controlled excavator Focus on soil adjacent to former process

buildings.



Trenching Investigation(continued):– Phase II –

Used shielded conventional excavator. Focus on process ditches & buildings similar to

those from Phase I. Used bulk (mechanized) excavation to

determine location and expose deposits Used forensic (hand dug) excavation to

determine detail of deposition of solid deposits.



Phase I excavation (at Finishing Plant)



Phase II excavation (at Refine ditch)


Northern Area InvestigationHistorical Buildings/Ditches

TNT



More excavation photos showing TNT.TNT Layer



More excavation photos showing TNT.



More excavation photos showing TNT.


TNT Removal Process

Collect & size pieces by hand Weigh, wet, and pack in antistatic bags Courier ship bags to St.Louis for incineration




Northern Area InvestigationPictures of Waste AreasWest Boyd Rail Fill



Slab Crossing Debris



Nitramon Area Container

Dump


Northern Area InvestigationPictures of Waste AreasCrushed Drum Dump



Typical surficial debris recovered.



Bare area photos.

Bare Area


Northern Area InvestigationPath Forward

Continue to determine distribution of site-related constituents.

– Four month field effort planned for 2006.– Explore feasibility of alternative investigation techniques.

Continue TNT recovery and disposal as part investigation efforts.

Continue debris identification and recovery. Continue to understand perchlorate distribution in

groundwater. Consider grid sampling in select areas. Continue pilot test work at GA Tech


Site-related Research Work

Continuing Georgia Institute of Technology research on destruction of DNT and TNT.

– Study being conducted by Dr. Joe Hughes (Professor and Chair of the Civil Engineering Dept. at Ga. Tech) and Dr. Jim Spain.

– Study initiated in early 2004 and is ongoing.– A portion of their research on TNT destruction was published in the

peer reviewed journal Environmental Science and Technology this year.

– Scaled-up DNT bioremediation project to address DNT contaminated soils is in progress at the Georgia Tech facility.

Soils used in the system are from the Barksdale site. System will run until all DNT degraded or other suitable

endpoint is reached Final results should be available by the end of 2006. Updates will be provided in future public meetings.


Proposed Barksdale Soil Biodegradation Pilot Proposed pilot project is a simple set up with low operation and

maintenance requirements.

Water, pH adjustment &

Nutrients (phosphate,

magnesium, calcium, iron)

DNT Biodegradation ReactorSite Soils

Contaminated w/ DNT (source of bacteria and DNT)

Gravel for Drainage

1 DNT 2 NO2

-

Methanol +NO2

-

N2 + CO2 + H2O

Methanol (wood alcohol)

Denitrification Reactor to Remove Nitrite

(bacteria from soils)








Southern Area InvestigationScope of Work

Worked with WDNR to develop a work plan to investigate southern area.– Focus of work was to:

Determine nature and extent of site-related constituents in surface soil.

Determine if current recreational use is appropriate.

– Work plan approved by WDNR. Site sampling was very comprehensive,

encompassing both grid-based and biased sampling at 640 locations (416 analyzed) over 400+ acres.


Southern Area Investigation Scope


Southern Area InvestigationPreliminary Findings

With the exception of one occurrence of benzo(a)pyrene at the residential screening level, arsenic and lead are the only constituents that exceed residential or recreational screening levels.

The extent of contamination is generally limited to soils along historic roadways in the central portion of the parcel. (The one exception being at select samples in the northeastern corner of the parcel.)


The nature and distribution of contamination is consistent with our understanding of historic site operations and our experience at other munitions manufacturing sites.

Arsenic and lead concentrations are well correlated, especially in samples that exceed their respective screening criteria. Hence, selected remediation of elevated levels of one constituent would also address the other.



The levels of lead and arsenic observed do not represent an acute health risk, and as such, use of this area for an additional season of occasional recreational activities would not be expected to result in unacceptable exposures.

A waste disposal area (1970s berm) was identified. Waste materials primarily consist of building rubble.



Southern Area InvestigationGrid Sizes



Insert maps/pictures of issues/findings.


Southern Area InvestigationIssues Identified


Southern Area Investigation1970s Berm


Southern Area Investigation1970s Berm

1970s Berm


Southern Area InvestigationSuggested Path Forward

Conduct additional sampling (Spring, 2006) for the purposes of delineating specific areas along historic roadways and railways.


Summary of Presentation

Priorities remain unchanged. Progress made in northern and southern

sections of property in 2005.– Over 400 pounds of TNT recovered and destroyed

in northern section in 2005, and several former process areas were investigated. Four months of field work are planned in 2006.

– Groundwater investigation resulted in detections of perchlorate. Additional samples to follow 2Q06.

– 640 locations sampled in southern section of the site (over 400 acres). Additional investigation of several areas is planned for 2006.


Questions or comments?

Documents

Former DuPont Barksdale Works Project Update December 14, 2005 Great Lakes Visitors Center DuPont CRG