NORTH CHARLESTON, SOUTH CAROLINA
BACKGROUND AND STATEMENT OF ISSUES
The U.S. Environmental Protection Agency (EPA) Region IV requested the Agency for Toxic Substances and Disease Registry (ATSDR), to review the analytical results of contaminated shellfish (i.e., clams, oysters, shrimp and crabs) samples obtained from Shipyard Creek, North Charleston, South Carolina, and to evaluate the health implications associated with human consumption of shellfish from the creek.
Shipyard Creek is a tributary of Cooper River in North Charleston, South Carolina. The Macalloy Corporation facility is situated on 125 acres at the headwaters of Shipyard Creek. Surface water runoff from the Macalloy facility enters Shipyard Creek. The facility has been operated continuously by various owners since 1941 as a ferro-chrome manufacturing facility. Macalloy Corporation has owned and operated it since 1979. The wastes generated from the facility during the ferro-chrome manufacturing process include the following: chromium; arsenic; lead; barium; manganese; mercury; and zinc.
An ecological study sponsored by the National Oceanic and Atmospheric Administration (NOAA) and EPA was conducted during the summer of 1997. Results revealed the presence of chromium contaminated shellfish and sediments in Shipyard Creek.
The study showed that fish tissue samples were contaminated, but at levels that did not pose a health threat if consumed by humans . The analytical results showed chromium at concentrations that exceed the Food and Drug Administration's (FDA) action levels in edible tissues in 95% of the shrimp, 26% of the blue crabs, and 15% of the oysters tested. Data also showed that shrimp, oysters and crabs contained chromium at concentrations greater than shellfish control samples from other areas outside of Shipyard Creek. The chromium concentrations ranged from 2.7 parts per million (ppm) to 34.3 ppm, 0.14 ppm to 24.3 ppm, and 7.5 ppm to 77.8 ppm, respectively, for eastern oysters, blue crabs, and shrimp from Shipyard Creek (see Attachment 1). The data were analyzed and confirmed by two separate independent statistical tests. The study did not characterize the valence state of chromium in the shellfish. It is assumed, since chromium is normally present in biological systems entirely as chromium III, that the levels reported are for chromium III.
Because of these findings, on April 30, 1998, the South Carolina Department of Environmental and Health Control (SCDEHC) issued an order pursuant to S.C. Code Annotated §44-1-140, that Shipyard Creek be closed to all harvesting or collecting of shrimp and crab from its mouth to its headwaters. That the existing closure for clams and oysters continue until the SCDEHC revokes the order . The EPA and SCDEHC announced that a Superfund removal at the Macalloy Corporation facility would be performed.
A Superfund removal is a short term clean up action to stabilize or clean up a site that poses an imminent and substantial threat to human health and the environment. The removal will be implemented to mitigate the immediate threat to human health and the environment by preventing site-related releases of contaminated storm water run off from entering into Shipyard Creek and adjacent wetlands. The removal action will consist of building a system of berms and drainage controls designed to collect storm water and the installation of a water treatment system to remove contaminants before discharge .