The study by the Medical University of South Carolina found elevated levels of PCBs in fish from Charleston Harbor and the Ashley and Cooper rivers, The Post and Courier of Charleston reported.
The study shows all of the fish tested exceeded the U.S. Environmental Protection Agency's limits for PCBs, compounds used in consumer products and industrial applications before they were banned in 1979.
The South Carolina Department of Health and Environmental Control says fish caught in the harbor and rivers can be eaten safely.
But DHEC spokesman Tommy Crosby said the agency is reviewing the findings by the medical university. The study could lead to recommendations on limiting consumption of fish from those waterways.
Spot fish, striped mullet, croaker, flounder, red drum and spotted sea trout were studied in the latest review.
PCBs have been identified by the EPA as possible cancer-causing materials.
Finding where the chemicals originated is a frustrating challenge, said Andrew Wunderley of Charleston Waterkeeper.
Other research has shown the harbor and the two rivers also contain pharmaceuticals, microscopic pieces of plastic, fabric fibers and other compounds, the newspaper reported.
Information from: The Post and Courier, http://www.postandcourier.com
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