(A DuPont Barksdale Dynamite Plant Operation)
FORMER DUPONT CLADDING SITE AT CABIN LAKE
(a/k/a DUPONT BARKSDALE EXPLOSIVES PLANT)
WASHBURN, BAYFIELD COUNTY, WISCONSIN
The Wisconsin Department of Health and Family Services (DHFS) evaluated soil sampling datafrom the former DuPont cladding site near Cabin Lake, in Bayfield County, Wisconsin.Explosive and inorganic compounds detected in soils were very low and pose no apparentpublic health hazard. Given the low levels of contaminants in soils, meat from deer or otheranimals found at the site is safe for people to eat. Investigations at the Cabin Lake site werelimited in scope. DHFS recommends discussion between the Department of Natural Resources(DNR) and E. I. DuPont de Nemours and Company (DuPont) about the need for additionalinvestigations. DHFS will continue to evaluate new sampling data that may come from the CabinLake site. DHFS will also continue to coordinate with Wisconsin DNR and Bayfield CountyHealth Department in addressing environmental health and public health issues that pertain to theformer DuPont properties and communities in Bayfield County.
Since 1995, DHFS staff have been involved with public health evaluations of environmentalcontamination at the former DuPont Barksdale Works, in Bayfield County, Wisconsin. DuPontmanufactured explosives at the 1,800-acre Barksdale plant site from 1905 to 1971. Duringdiscussions with the community and other agencies, DHFS received anecdotal reports thatDuPont also conducted metal cladding operations at a remote location near Cabin Lake, withinthe Chequamegon National Forest. Citizen reports to DHFS included descriptions that the formerDuPont cladding site near Cabin Lake is devoid of vegetation because wildlife continuously digand ingest surface soils at the site. Several community members said the site was a good place tohunt because deer are attracted to something in the soils. DuPont also reported it previouslyconducted metal cladding operations at Cabin Lake. Explosive metal cladding is an industrialprocess that fuses different types of sheet metal using high explosives.
On the morning of May 25, 2001, staff from DHFS and DNR visited the Cabin Lake site. Whenwalking onto the site, staff saw several deer fleeing from an approximately 3-4 acre clearing intothe forest. A large portion of this clearing had little or no vegetative cover. In some locations,surface soils were loose and completely covered with deer hoof prints. These hoof marks weremade since morning, when it had rained. Deer had apparently dug with their hooves down todeeper soils at a number of locations, with the deepest holes being 2-3 feet deep. Pieces of metaldebris and short lengths of wires were randomly dispersed in soils across the property. Metal andwood debris protruded from the walls inside several holes, suggesting these soils were previouslydisturbed by human activities. During the site visit, agency staff saw a deer return to the openarea of the site, walk into a dug depression, stop, and regularly lower its head, apparentlyingesting soils.
On July 11, 2001, DHFS and DNR staff returned and collected soil samples from the Cabin Lakesite. Six surface soil samples were collected from selected locations, including inside and nearpoints that were dug by wildlife. These samples were submitted to the Wisconsin StateLaboratory of Hygiene and analyzed using U.S. Environmental Protection Agency Method8270C. This method targets 68 semivolatile organic compounds, including the two mostcommon isomers of dinitrotoluene (2,4- and 2,6-dinitrotoluene). Trace amounts of di-n-butylphthalate were found in soil samples. Di-n-butyl phthalate was also detected at similarconcentrations in the laboratory blank, suggesting the compound was a laboratory artifact and notactually present in soils at the site (1).
On August 14, 2001, DuPont staff visited the Cabin Lake site and collected surface and sub-surface soil samples from 10 locations. These samples were analyzed for nitroaromatic andnitramine organic compounds, inorganic compounds, semivolatile organic compounds, andvolatile organic compounds. DuPont reported their findings in September 2003 (2). These resultsare summarized in Table 1. DuPont concluded that none of the compounds found were "a threat to human health."
|Chemical||Highest Level Detected||Lowest Level Detected||Frequency of Detection||Health Comparison Value|
|2,4-dinitrotoluene||0.11||-||1/10||100.0† - child |
1,000.0† - adult
|2,4,6-trinitrotoluene||0.016||-||1/10||100.0† - child |
1,000.0† - adult
|Copper||411.0||8.1||10/10||2,000.0 ‡ - child |
20,000.0 ‡ - adult
* U.S. Environmental Protection Agency's Region III Provisional Health Value.
† Agency for Toxic Substances and Disease Registry's Chronic Environmental Media Evaluation Guide.
‡ Agency for Toxic Substances and Disease Registry's Intermediate Environmental Media Evaluation Guide.
§U.S. Environmental Protection Agency's Residential Soil Cleanup Guideline for Lead.
DHFS concludes that the contaminants found in soils at the former DuPont cladding site at CabinLake pose no apparent public health hazard. Table 1 shows the results of the DuPontinvestigation and corresponding health-based environmental comparison values used by DHFS inevaluating the public health implications of the detected compounds. DHFS's conclusion isbased on the fact that all detected explosive compounds were less than the lowest, human health-based comparison value. Lead and copper were also detected in samples from all locations, but atlevels typical of those found in soil at this location and below levels associated with healtheffects.
People have asked DHFS whether wildlife that eat soils at the Cabin Lake cladding site maycontain elevated levels of explosive contaminants. They then ask whether meat from this game isfit for human consumption. It is evident that deer and other animals are ingesting soils at theCabin Lake site. Nitroaromatic explosive compounds do not bioaccumulate nor persist in animaltissues (3). These chemicals, when ingested by people or animals, are rapidly excreted throughurine or feces. Given the low levels of contaminants found at the site, and their tendency not toaccumulate in animal tissue, meat from deer or other animals at the site is safe to eat.
From the reported history of the cladding site at Cabin Lake, the presence of physical debris, andchemical residual contamination, it is apparent that past industrial operations have leftenvironmental effects. Available sampling data did not reveal levels of contamination that wouldbe of concern to human health, but the investigations were limited in scope. DHFS recommendsfurther discussion between DNR and DuPont on whether there is a need for additionalinvestigation of other environmental media at the Cabin Lake site.
Contaminants found at the former DuPont cladding site at Cabin Lake pose no apparent publichealth hazard to children who may regularly visit and play there. DHFS includes children whenevaluating exposures to contaminants and considers children as the most sensitive portion of thepopulation that was evaluated in this public health consultation. Additionally, DHFS consideredthat children may live near or regularly visit the former DuPont cladding site at Cabin Lake. TheCabin Lake site is remotely located within the Chequamegon National Forest, with the nearesthome several miles away. Given the low accessibility of the Cabin Lake site to young children,any potential child health risks are much less than for a site in a residential or urban setting.
- Organic compounds and inorganic chemicals detected in soils at the former DuPont cladding site at Cabin Lake were very low and pose no apparent public health hazard.
- Given the physical properties and low levels of contaminants found in soils at the Cabin Lake site, meat from deer or other animals found there is safe for people to eat.
- Investigations at the Cabin Lake site were limited in scope and additional investigations may be needed.
DHFS recommends that DNR further evaluate how people use the Cabin Lake site to determine whether other environmental media should be sampled.
- DHFS will discuss possible human exposure to contaminants at Cabin Lake with DNR andwill continue to review and evaluate the human health implications of new sampling datafrom the Cabin Lake site.
- DHFS will continue to coordinate with Wisconsin DNR and Bayfield County HealthDepartment in addressing environmental health and public health issues pertaining to theformer DuPont properties and the communities in Bayfield County.
- Wisconsin Department of Natural Resources. Memorandum to Sally Hess-Samuelson, USDAForest Service, from Christopher Saari, Wisconsin DNR, concerning soil sample results fromthe former DuPont Cabin Lake cladding area. Ashland, Wisconsin. October 12, 2001.
- DuPont Engineering. Soil sample results: Cabin Lake area of the Chequamegon NationalForest, Bayfield County, Wisconsin. Louisville: DuPont. September 23, 2003.
- US Environmental Protection Agency. Health advisory for 2,4- and 2,6-dinitrotoluene.Washington, DC: US Environmental Protection Agency. EPA No. 820R92002; NTISPublication No. PB92-189315. 1992 Apr.
Henry Nehls-Lowe, MPH
Bureau of Environmental Health
Division of Public Health
Wisconsin Department of Health and Family Services
This Former DuPont Cladding Site at Cabin Lake health consultation was prepared by theWisconsin Department of Health and Family Services under a cooperative agreement with theAgency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health consultation was begun.
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this healthconsultation and concurs with the findings.
Chief, SPS, SSAB, DHAC, ATSDR