The study was presented Wednesday at the yearly meeting of the American Public Health Association.
The team also put forward a separate study. This showed that wild fish sold commercially contained higher levels of mercury, arsenic and selenium than fish caught near former industrial areas of Lake Erie. Coal-burning pollution is marked by the presence of mercury, arsenic and selenium in fish.
Three studies were presented at a special session on contaminants in freshwater fish.
The first study found high amounts of mercury and selenium in channel catfish caught in a rural area upstream of Pittsburgh and near a coal-fired power plant. Mercury and selenium are well-known contaminants resultant of burning coal for power generation.
Local anglers caught channel catfish from the three rivers area of Pittsburgh, where the Allegheny, Monongahela and Ohio rivers meet, at the behest of researchers.
The anglers also caught catfish from the Allegheny River at Kittanning, 40 miles upstream from Pittsburgh and downwind of Reliant Energy's Cheswick Power Station in Springdale, 26 miles away.
According to lab tests, there was 19 times more mercury and three times more selenium in the Kittanning-caught fish than in the three rivers area fish.
The risk of developing neurological disorders from eating catfish with such high levels of mercury as those caught near Kittanning is eight times higher than the U.S. Environmental Protection Agency's acceptable risk for children under six years of age, six times higher for women of childbearing age, and five times higher for the general population, warn the researchers.
"Given these results, we should be concerned about fish caught in areas that are situated close to coal-plants, even if upstream from more heavily polluted areas," says lead investigator Dr. Conrad Volz, assistant professor at the University of Pittsburgh Cancer Institute, Center for Environmental Oncology.
Volz is co-director for exposure assessment in the Department of Environmental and Occupational Health.
"These types of power plants may be significant sources of mercury and selenium in fish contamination," he adds.
Pat Hammond, communications director for Reliant Energy based in Houston, Texas, gives that though company officials have not seen the study the plant is in compliance with its air and water permits.
Reliant had declared last year it would spend $250 million to install a flue gas desulfurization scrubber at Cheswick.
"We believe it is important for fish consumption advisories to take into account industries such as power plants that may be important sources of water pollution, and warn people in these areas about the dangers of consuming local fish", says Volz.
In a second study Volz found that white bass wild-caught in the Canadian part of Lake Erie contained higher levels of mercury, arsenic and selenium than fish caught near former iron and steel mills on the Allegheny and Monongahela rivers in Pittsburgh.
"We were surprised by our results since we had hypothesized that levels of contaminants in fish would be higher in specimens caught near once heavily polluted sites," says Volz.
"These results indicate to us that purchasing fish from a local market cannot guarantee food safety," he adds. "We recommend a more rigorous testing program for commercial freshwater fish with particular attention to fish entering the U.S. from other countries."
Volz gives that the results may indicate that sediments in Lake Erie remain toxic because reductions in industrial pollution are just recent, while coal-fired power plants and wastewater treatment plants around Lake Erie and to the southwest continue to emit pollutants.
Volz put forward a third study which showed that exposing estrogen-sensitive breast cancer cells to extracts of channel catfish caught in areas of the Allegheny and Monongahela rivers near Pittsburgh with heavy sewer and industrial waste caused the cells to multiply.
The study suggests that the fish have substances that mimic the actions of estrogen.
"We believe there are vast quantities of pharmaceutical and xeno-estrogenic waste in outflows from sewage treatment plants and from sewer overflows, and that these chemicals end up concentrated and magnified in channel catfish from contaminated areas," warns Volz.
"These findings have significant public health implications, since we drink water from the rivers where the fish were caught," he says. "Additionally, the consumption of river-caught fish, especially by semi-subsistence anglers, may increase their risks for endocrine-related health issues and developmental problems", he warns.
The three studies were funded by grants from the Highmark Foundation, the DSF Charitable Trust and the Heinz Endowments.