Former DuPont Barksdale Works Project Update June 07, 2006 Great Lakes Visitors Center DuPont CRG

Former DuPont Barksdale Works Project Update

June 07, 2006Great Lakes Visitors Center

DuPont CRG

June 7, 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

Barksdale:– Reaffirm site priorities and public commitments.– Provide an update on work completed since the

December 2005 public meeting.– Provide an overview for planned work for 2006.

Chequamegon-Nicolet National Forest:– Provide a status update on activities.

Barksdale 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.


Home Value Protection Plan

Home Value Protection Program has expired.– Last municipal water connection was in June

2005.– Eligibility expired for the final group of residents

in 4Q2006. – A single vacant lot is the only residential property

currently in the program and sale of the property is pending.


Work Completed in 2006

Alternative Water Supply– Managing invoices, supply, and maintenance

with Washburn.– To date, DuPont has paid $93,620.86 in related

water supply costs to Washburn.– Well abandonment documentation sent to

homeowners and WDNR.



Georgia Tech Bio-Pilot– DNT isomers not currently detected in aqueous

phase.– System was operated for 5 months and a 90%

reduction was observed.– Soil from system taken back to lab to further

determine limits of degradation.



Site Investigation Work– 2006 Work plan submitted to WDNR in March.

Preliminary approval has been received from WDNR.

Planned 2006 Site InvestigationCary Pooler


2006 Site Investigation

2006 Site Investigation– Investigation has two geographic focus areas:

Northern Area– Investigation multi-faceted.

Southern Area– Investigation focusing on surface soils.

– Investigation to begin this month.– Estimated completion of field work is September

2006.– Reporting by the end of the year.


Northern Area InvestigationPlanned Work

Determine distribution of site-related constituents.– Trenching.– Grid sampling in select aeas.

TNT recovery and disposal as part investigation efforts.

Debris identification and recovery. Perchlorate distribution in groundwater.










Insert maps/pictures of issues/findings.




Southern Area InvestigationGrid Sizes


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 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 InvestigationPreliminary Findings




Southern Area InvestigationPlanned Work

Conduct additional sampling for the purposes of delineating specific areas along historic roadways and railways.

Chequamegon-Nicolet National Forest UpdateBrad Nave


Chequamegon National Forest

National Forest Service contacted DuPont in April 2006.– Requested DuPont work with Forest Service to

develop a framework for future actions within the National Forest.

– DuPont met with USDA-FS on June 7, 2006 to discuss path forward.

– Future work will address both the Cabin Lake and Clover sites.



Questions or comments?


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.

Documents

Former DuPont Barksdale Works Project Update June 07, 2006 Great Lakes Visitors Center DuPont CRG