DuPont Barksdale and Chequamegon Projects Update

DuPont Barksdale and Chequamegon Projects Update

December 12, 2007

DuPont CRG

Great Lakes Visitors Center

December 12, 2007 DuPont Barksdale and Chequamegon Projects Update

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Purpose of MeetingBarksdale:

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.


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DuPont RepresentativesBrad Nave – DuPont, Sr. Site DirectorJon Hammerberg – URS Corporation, Sr. Project Engineer

Former DuPont Barksdale Works Project Update


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Barksdale Project PrioritiesCurrent Priorities:

Identify priority source areas and take appropriate action.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.


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Barksdale Project PrioritiesOther 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.

Summary of 2007 Barksdale Work


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Reported Investigation Results Prepared a 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.



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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.



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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.

Summary of 2007 Work


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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.

Current Conditions Report Summary


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Current Conditions Report SummaryPriority 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


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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.

2007 Site Investigation Work


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Overview 2007Site InvestigationActivities:

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


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2007 Investigation Priorities


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Clearing Work SitesCleared:

• Four miles of new trails.

• X-acres of sample sites.


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Screening with Geophysics (EM61)

Used to:

• Map metallic debris.

• Locate metallic pipe lines.

• Locate utility lines.

• Identify changes in soil conductivity.


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Geophysics EM61 Results— PAI

1731800 1731850 1731900 1731950 1732000 1732050 1732100 1732150 1732200 1732250 1732300 1732350 1732400 1732450 1732500 1732550 1732600 1732650 1732700 1732750 1732800 1732850 1732900 1732950 1733000 1733050 1733100 1733150

533900

533950

534000

534050

534100

534150

534200

534250

534300

534350

534400

534450

534500

534550

534600

534650

534700

534750

534800

PRELIMINARY


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Trench InvestigationUsed to:

• Verify geophysical detections.

• Locate & sample non-metallic pipes.

• Locate & sample foundations.

• Recover buried TNT.

• Profile process ditches.


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Trench Sampling at Foundations


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Trench Sampling at Foundations


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Recovering TNT fromCatch Box

Total of 1,920 pounds of soil and TNT recovered and disposed in 2007 (contained 470 pounds of TNT ).


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Profiling Product Residues in Ditch

TNX


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FIDO Analysis Equipment


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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.


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TNT Located Using Cartridges and FIDO

TNT found by FIDO visible only after tall grass & sheet metal hiding it was removed.


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Drilling and Soil Sampling


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Soil Samples


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Removing Asbestos

250-lf of exposed pipe insulation was removed.


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Waste Water Treatment and Disposal

2,500 gallons removed in 2007.


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Debris and Scrap Metal Recovery


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Debris and Scrap Metal Disposal

Total of 50 cubic yards of scrap removed to date.


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Off-site Monitoring Project SummaryPer 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.


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Off-Site Monitoring Results

2007 Administrative Efforts


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Priority Rankings 2007


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Proposed Priority Rankings—2008


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Closure RequestRequest 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.


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Pending Closure Request Area South of Boyd Creek

Remedial Technology Evaluation

DNT Biodegradation Study


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DNT Pilot - BackgroundPurpose:

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.


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Barksdale Field DNTBio Pilot


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Project Setup and ChallengesArea 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).


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Results and Conclusions2,4 DNT

0

5000

10000

15000

20000

25000

30000

35000

June August September October

Month Sampled

Co

nce

ntr

atio

n (

ug

/kg

)

Control

Cell 2

Cell 3

Cell 4

2,6 DNT

0

10000

20000

30000

40000

50000

60000

June August September October

Month Sampled

Co

nce

ntr

atio

n (

ug

/kg

)

Control

Cell 2

Cell 3

Cell 4

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.

Additional Target Analytes


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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.

Additional Target Analytes


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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.

Barksdale Path Forward

Chequamegon-Nicolet National Forest Update


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Chequamegon-Nicolet National ForestProject Summary:

DuPont is working with the US Forest Service (USFS) to investigate two former metal cladding sites (Cabin Lake and Clover).

Metallic debris delineation completed at Cabin Lake in late 2006, while debris delineation was completed at Clover in May 2007.

Debris delineation report submitted to USFS on June 7, 2007.


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Chequamegon-Nicolet National ForestIn June 2007, DuPont and USFS representatives met to discuss debris delineation results and plan the next phase of investigation activity(soil sampling).

During this meeting, USFS personnel informed DuPont that there are four potential cultural resource areas in the vicinity of the Cabin Lake and Clover sites and that DuPont must conduct an archaeological evaluation.

DuPont and USFS conceptually agreed on the scope of soil sampling work:

• Sampling work will include biased soil sampling and trenching at both sites where the most concentrated metallic debris was identified.

• Sampling work will include sediment and surface water sampling from within Cabin Lake.


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Chequamegon-Nicolet National ForestSince June 2007, DuPont and USFS representatives have:

Determined which potential locations will be subject to archaeological study.

• One area at Cabin Lake (a former logging camp) will require further study.

• Remaining sites are outside of DuPont’s investigation area and are not subject to archaeological study.

Completed a joint field reconnaissance in November 2007 of the archaeological areas.

Conceptually agreed on the scope of archaeological work:• Historical file review of location at Cabin Lake.• Work plan development and approval.• Completion of archaeological study.


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Cabin Lake Geophysical Findings


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Clover Geophysical Findings


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Chequamegon-Nicolet National ForestPath Forward:

DuPont is currently completing the historical file review and developing the archaeological work plan.

Once archaeological field work is complete and reported (estimated summer 2008), DuPont will submit the final work plan for the environmental investigation to USFS for review and undertake the proposed work, pending appropriate archaeological permits from Wisconsin and USFS.


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Questions or comments?

Documents

DuPont Barksdale and Chequamegon Projects Update