CLARKSVILLE, BUTLER COUNTY, IOWA
The Iowa Department of Public Health (IDPH), Hazardous Waste Site Health Assessment Program, prepared this health consultation for the Clarksville PCB site located in Clarksville, Butler County, Iowa, at the request of U.S. Environmental Protection Agency (EPA) Region 7. IDPH was asked to determine whether contamination at the Clarksville PCB site poses a public health hazard. The information reviewed in preparation of this health consultation was current at the time of writing. Any site-related information forthcoming later could alter the conclusions and recommendations presented.
The Clarksville PCB site is located on the northwest edge of the city limits of Clarksville, Butler County, Iowa. Clarksville is a rural community of approximately 1400 persons. Of these, 108 are less than five years of age, and 311 are 65 years of age or more (1). The median age of residents is 39 years.
The site itself is an undeveloped 7.7 acre lot adjoining the Butler County Sportsmen's Park. Sportsmen's Park is a 30 acre park owned by Butler County and maintained by the local conservation district. Access to the site is unrestricted, though difficult because of its relatively remote location and the presence of dense vegetation throughout the area. A salvage yard lies immediately to the east of the site, and, in fact, constitutes the eastern site boundary. The nearest residences are approximately 500 feet to the north and east of the site. The Sportsmen's Park ponds and recreation area lie to the west.(2, 3). A cemetery and gravel pit are directly south of the site. Currently, there are no plans to develop the site.
The site was formerly a part of the adjacent salvage yard; however, no salvage activities have transpired there since 1986 (2). The Butler County Department of Public Works is now using the site for disposal of construction debris. The few areas of open space on the site contain piles of rubble and old concrete from road maintenance.
From 1977 until 1984 the salvage yard owner leased the 7.7 acre Clarksville PCB site, and used this area to store old vehicles, automotive batteries, and scrap metals. It has been alleged that electrical transformers were at one time salvaged or stored there, although this could not be confirmed by the U.S. Environmental Protection Agency's inspection (4). Upon termination of the lease, all remaining salvage materials were removed.
Contaminants of concern at this site include polychlorinated biphenyls (PCBs) and lead in soil, sediment, and surface water. In the past, PCBs were commonly used in fire retardant and electrical insulating applications (5). PCBs are not naturally-occurring compounds, and their presence at the Clarksville site is most likely the result of previous salvaging activities. Lead is a component of lead-acid batteries, used in automobiles and other vehicles. The fact that batteries have been stored on site in the past indicates that this might be the source of lead in soils.
A removal site evaluation at Clarksville PCB was conducted by EPA Region 7 during July 2001. The purpose of this evaluation was to identify the extent of lead and PCB contamination in soil, water, and sediments at the site (3).
Eleven surface soil samples taken at a depth of 0-2 inches were collected during the evaluation. These were subsequently analyzed for PCBs and lead. Deeper samples could not be collected because of the very dense vegetation cover, the presence of numerous rubble piles, and the limited amount of surface soil present at the site (3). Because of these limitations, screening of soils for lead was done using a portable x-ray fluorescence (XRF) spectrometer. Seventy-three such screening samples were taken throughout the site. Five sediment samples were collected at the site and around ponds within the nearby Sportsmen's Park. Water samples were collected from a pond in the Sportsmen's Park and from a shallow groundwater well within the Park (3).
Laboratory and screening results showed only limited areas of contamination. Five of 11 soil samples contained detectable amounts of PCBs, and one location had as much as 3.8 milligrams of PCBs per kilogram of soil (mg/kg). This concentration exceeds the Agency for Toxic Substances and Disease Registry's (ATSDR) cancer risk evaluation guideline of 0.4 mg/kg of PCBs in soil for chronic (greater than 364 days) exposures. Only one sediment sample had detectable levels of PCB's (0.14 mg/kg). No PCBs were found in surface waters or groundwater.
Lead was detected in surface soil samples at concentrations ranging from 20-1,910 mg/kg. The two highest results for lead in soil were 1,810 mg/kg and 1,910 mg/kg, both from isolated locations on the site. The 73 XRF readings confirmed these were the only two areas containing elevated concentrations of lead; no other lead concentrations exceeded 300 mg/kg. Sediments from the adjacent Sportsmen's Park contained lead in concentrations ranging from 3.0-49.7 mg/kg. At present, neither EPA nor ATSDR have established health-based guidelines for lead contamination in soil or sediment (6). Lead in water ranged from undetected to 13.8 micrograms per liter (µg/L), which is below the regulatory standard of 15 µg/L for lead in drinking water. (3)
Possible exposure pathways at the Clarksville PCB site could originate from air, soil, or water. The relevant routes for human exposure are ingestion of PCB- or lead-contaminated soil and water. Site trespassers and neighborhood children, who might play on the site, are potential candidates for exposures. However, during a site visit made by IDPH staff in July 2001, no evidence of children or trespassers on the site was observed. This might be in part because the site is relatively difficult to access.
From results of the recent sampling, it does not appear that site contaminants pose a threat to human health. PCB contamination at the site is not widespread, and only 5 of 11 samples contained detectable levels of PCBs. PCBs at one soil sampling location did exceed a health-based exposure guideline, although exceeding this guideline does not necessarily mean that a health hazard exists. The isolated nature of the PCB contamination at the site makes the possibility of exposure to the most contaminated soil unlikely. Also, dense vegetative and man-made soil cover (construction debris)exist on the site, which greatly limits accessibility to areas of contamination. Concentrations of PCBs in sediments are very low and are below the level of health concern. Exposure to PCBs via ingestion of water is not an issue, as no PCBs were detected in either surface or groundwater samples.
No health-based comparison values for lead in soil are currently available from either ATSDR or EPA. Nevertheless, the lack of accessibility to contaminated soil makes lead exposure unlikely. As with PCBs, the isolated nature of elevated lead concentrations greatly limits the potential for ingestion of contaminated soil. Because the contamination is not widespread, and because soil cover limits contact with bare soil, it is improbable that any significant exposure would occur. Water sampling revealed that lead concentrations are below any existing health guidelines or advisory levels. Sediments contain lead but at very low concentrations. No adverse health effects should be expected from exposure to lead in either sediment or water.
An important part of the health consultation process is the assessment of potential impacts of hazardous waste sites on children. This is especially true at sites at which direct contact with contaminated soils and dust is a potential pathway of exposure. Because of children's activity patterns and greater sensitivity to hazardous substances, children usually are considered the most sensitive populations for exposure at hazardous waste sites. The effects of lead ingestion on children are well documented. Ingestion of lead-contaminated soil in sufficient amounts and at sufficient concentrations can cause a variety of neurological and learning impairments in children (6). It has been suggested that exposure to PCBs also might have a greater effect on children than adults, although this has not been proven. Many of the studies examining possible relationships between environmental exposure to PCBs and adverse health effects have serious flaws which limit their usefulness (5).
It is unlikely that children have been, or will be, exposed to contaminants at the Clarksville PCB site. In a few locations, elevated concentrations of PCBs and lead in soil exist, but the risk of exposure to children is slight, for the reasons outlined in the previous section (contamination is not widespread, and extensive soil cover exists, thus limiting accessibility. Additionally, sediment and water samples from the site do not contain PCBs or lead at levels which would be of health concern.
- Under current site conditions, contamination of soil, sediment, and surface water at the Clarksville PCB site presents no public health hazard. If site use does not change, the site is expected to present no apparent public health hazard in the future.
- Re-evaluate the need for further actions if site use changes.
- It does not appear that, under present site conditions, health education efforts are warranted. However, IDPH will monitor future site use, and should conditions change, the need for health education and community involvement efforts will be re-evaluated.
- Data provided by the State Library of Iowa Information Center. Des Moines, IA; January 2002.
- Ecology and Environment, Inc., Site Inspection Report for The Ackerman Salvage Company Site, Clarksville, Iowa. CERCLIS No. IAD984562642. [Lenexa, KS: Ecology and Environment, Inc.; March 6, 2000.
- Removal Site Evaluation report, Clarksville PCB site, Clarksville, Iowa. Prepared for U. S. EPA Region 7. Lenexa (KS): Tetra Tech EM, Inc.; November 2001.
- Report of RCRA Complaint Investigation at the Ackerman Auto Truck Tractor and Salvage Company. Clarksville, Iowa. [Kansas City, KS: US Environmental Protection Agency Region 7.; July 9, 1992.
- Toxicological profile for polychlorinated biphenyls (PCBs). Prepared for the Agency for Toxic Substances and Disease Registry. Syracuse (NY): Syracuse Research Corporation; November 2000. (Contract No. 205-1999-00024.)
- Toxicological profile for lead. Prepared for the Agency for Toxic Substances and Disease Registry. Research Triangle Park (NC): Research Triangle Institute; July 1999. (Contract No. 205-93-0606.)
Hazardous Waste Site Health Assessment Program
Iowa Department of Public Health
ATSDR Regional Representative
Office of Regional Operations, Region VII
Office of the Assistant Administrator, ATSDR
ATSDR Technical Project Officer
Division of Health Assessment and Consultation
Superfund Site Assessment Branch
LTJG Shawn Blackshear
ATSDR Regional Representative
Office of Regional Operations, Region VII
The health consultation for the Clarksville PCB site was prepared by the Iowa Department of Public Health, Hazardous Waste Site Health Assessment Program, under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health consultation began.
Technical Project Officer, SPS, SSAB, DHAC, ATSDR
The Division of Health Assessment and Consultation, ATSDR, has reviewed this health consultation, and concurs with its findings.
Chief, SPS, SSAB, DHAC, ATSDR