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The proposed Potter Company National Priorities List (NPL) site in Wesson, Mississippi is not currently a public health hazard based on the Agency for Toxic Substances and Disease Registry (ATSDR) evaluation of available environmental and health outcome data and community health concerns. However, the residents of Wesson and students and staff of Copiah-Lincoln Community College were exposed to trichloroethylene (TCE) in the Wesson Municipal Water Supply for up to 15 years. It is uncertain whether this exposure may have resulted in adverse health effects.

The TCE contamination came from the Potter Company which used TCE to clean polychlorinated biphenyls (PCBs) from the electrical capacitors that the company manufactured. The use of TCE from 1954-1975 and PCBs from 1959-1968 resulted in the contamination of the soil around the facility with PCBs and the contamination of ground water with TCE. The PCB-contamination was discovered in 1986 and the PCB-contaminated soil removed by April 1993. The TCE contamination in ground water was identified in 1987 and temporary measures to reduce exposure were taken quickly. All exposures to the contaminated groundwater ceased in 1989 by switching to uncontaminated wells.

Additional activities that should be conducted regarding the Potter NPL site are the testing of the ground water for PCBs, and the determination of the length of time that the Wesson Municipal Water Supply system was contaminated. Depending on the results of this modelling, a cancer mortality data review for Wesson, and an epidemiologic study of Wesson residents should be considered.


In this public health assessment, the Agency for Toxic Substances and Disease Registry (ATSDR) evaluates the public health significance of the proposed Potter Company National Priorities List (NPL) site in Wesson, Mississippi. More specifically, ATSDR has reviewed available environmental and health outcome data, and community health concerns to determine whether adverse health effects are possible. In addition, this public health assessment recommends actions to reduce, prevent, or further identify the possibility for site-related adverse health effects. ATSDR, in Atlanta, Georgia, is one of the agencies of the U.S. Public Health Service. ATSDR is required by the Superfund law (Comprehensive Environmental Response, Compensation, and Liability Act of 1980 [CERCLA] as amended by the Superfund Amendments and Reauthorization Act of 1986 [SARA]) to conduct public health assessments of hazardous waste sites proposed for the National Priorities List (NPL) within one year of the site's proposal for the NPL.

A. Site Description And History

The proposed Potter Company NPL site is located in the City of Wesson, Copiah County, Mississippi. The City of Wesson is approximately 43 miles southwest of Jackson.

Since 1953, the Potter Company facility has manufactured electronic components. Presently, the facility occupies approximately 10 acres and is bordered by Highway 51 to the west and Fourth Street to the north (see Appendix 1, Figure 1) (1). Four buildings are presently at the facility: the original manufacturing and office building, a newer metal warehouse building (housing manufacturing operations), a frame storage building (previously housed a degreasing operation), and a former one story residence (purchased by Potter Company in 1988 - the Byrd property). A large paved parking lot is located adjacent to the manufacturing buildings. The remaining property, approximately five acres, is wooded.

In 1986, Potter Company was sold by Varian Associates, Inc (2). At that time, employees expressed concern over how waste materials had been handled at the plant. Subsequent sampling in April and May 1986 detected polychlorinated biphenyls (PCBs), primarily Aroclor 1254, and solvents in surface soils at the facility and PCBs in surface soils on the adjacent residential property (purchased by Potter Company in 1988) and drainage ditches off the Potter property. PCB oils were used in capacitors manufactured at the plant from 1959-1968. The equipment manufactured at the plant was cleaned (degreased and excess PCBs removed) with solvents, trichloroethylene (TCE) from 1954 to 1975 and 1,1,1-trichloroethane (TCA) from 1975 to the present.

In May 1986, the State of Mississippi ordered Potter to determined the extent of PCB contamination in soils, develop a plan to remove the contaminated soils, and install monitoring wells (2-4). By April 1993, Potter Company had removed over 6,500 cubic yards of PCB contaminated soil from the plant facility, the adjacent residential property, and the unnamed stream off the company property. The contaminated soils were disposed of in permitted hazardous and solid waste landfills. These remediation activities have removed all PCB soil contamination above ten parts per million (ppm) at the Potter manufacturing facility and any PCB soil contamination above one ppm in the unnamed stream off-site and on the Byrd property.

The Mississippi Bureau of Pollution Control and the Mississippi Department of Health sampled the two municipal wells for Wesson (Wesson wells number 1 and 2, approximately 1,000 feet southeast of the Potter Company facility) in August 1987 (5). The results of the laboratory analysis conducted on the samples indicated that the wells were contaminated with significant amounts of TCE. In September 1987, the citizens of Wesson were informed that their drinking water was contaminated with TCE. The city and state advised the citizens to either boil their drinking and cooking water or obtain water from a source not containing TCE until a permanent solution for eliminating the TCE from the Wesson water supply was implemented. Bottled water was provided for students at the Copiah-Lincoln Community College.

By May 1988, the aerator at the Wesson water treatment plant had been modified to reduce the concentration of TCE in the drinking water (5). However, this modification did not reduce the TCE concentration in the city's drinking water below the maximum contaminant level (MCL) specified by the U.S. Environmental Protection Agency (EPA) under the Safe Drinking Water Act [i.e., five parts per billion (ppb) or 0.005 ppm].

New wells (Wesson wells number 3 and 4) were drilled one mile southeast of the old wells. Analysis of samples taken from these wells indicated no TCE contamination (5). These new wells were connected to the Wesson municipal water distribution system in June 1989. The old wells were then closed by the city.

On September 30, 1991, the State of Mississippi Bureau of Pollution Control approved the remediation action plan proposed by the Potter Company and their consultants for cleaning up groundwater contamination (6,7).

EPA proposed that the Potter Company site be placed on the NPL on May 10, 1993 (2).

B. Site Visit

A site visit was conducted by ATSDR staff (Mr. Sven E. Rodenbeck and Dr. John Crellin from ATSDR Headquarters in Atlanta, Georgia, and Mr. Robert E. Safay from the ATSDR Region IV Office) on December 7 and 8, 1993. The site visit was conducted to collect information needed for the Public Health Assessment for the proposed Potter Company NPL Site (Update 14). Public Availability Sessions were held on December 8. In addition, meetings were held with EPA, Mississippi Department of Health, Mississippi Department of Environmental Quality, and the consultant for the Potter Company.

The following observations were made during the site visit: 1) the known area of PCB soil contamination has been remediated, 2) groundwater monitoring wells have been installed to determine the extent of groundwater contamination, 3) most of the groundwater treatment systems (e.g., air strippers) are at the Potter Company, and 4) the drinking water supply wells for the Lincoln Rural Water Association and the City of Wesson are southeast of the Potter Company.

C. Demographics, Land Use, and Natural Resources Use

During the 1980 census, the City of Wesson had a population of 1,313 (2). Drinking water is provided to all the city residences by the Wesson municipal drinking water supply system. In addition to providing drinking water to city residences, the system also provides drinking water for the Copiah-Lincoln Community College. Approximately 1,000 students attend the Community College.

Wesson well numbers 1 and 2 were constructed in 1971 and 1974 respectively. Prior to 1971, the city residences were provided drinking water obtained from a spring system (5). The spring is located southeast of the proposed Potter Company NPL site and was used by the City as the only source for drinking water from 1922 to 1971.

In 1986, Copiah county had a population of 26,952 (50.3 percent White and 49.7 percent African-American). Approximately 47.7 percent of the Copiah county population is male (52.3 percent female).

The land surrounding the proposed Potter Company NPL site is used primarily for residential areas.

A small drainage ditch is located near the southern property line of Potter Company. The ditch discharges into a unnamed stream. No fishing is conducted in the unnamed stream because it is frequently dry.

D. Health Outcome Data

Using state and federal health databases, it may be possible to determine if there is a higher than expected number of certain health effects in Wesson or Copiah County. Cancer was identified as a plausible health outcome and a community health concern. Cancer mortality data from the National Center for Health Statistics were evaluated. The results of this evaluation are discussed in the Health Outcome Data Evaluation section of this Public Health Assessment.


During the December site visit, ATSDR staff met with local government officials, EPA officials, Mississippi Department of Health officials, and individual citizens (during the public availability sessions). The only community health concern mentioned to ATSDR was:

Is the occurrence of cancer elevated in this area?

This concern is addressed in the Health Outcome Data Evaluation section.

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