IU scientists study toxins in Great Lakes
Written by Associated Press   
Sunday, 28 November 2004 10:33

Indiana University scientists are leading a federal effort to track the fluctuation of PCBs, pesticides and other toxins in the Great Lakes basin.

IU recently received a $3.5 million Environmental Protection Agency grant to continue operating a network of instruments on the five lakes -- Huron, Ontario, Michigan, Erie, and Superior -- which are the world's largest source of fresh water.

The study is part of a cooperative effort with Canada to measure pollutants coming from the air. IU has operated the network since 1994.

"We're trying to understand how (the toxins) behave; how compounds move around, where they come from and how fast they go from place to place," said Ronald A. Hites, an IU professor who is an internationally known expert in environmental toxins.

Earlier this year, Hites co-authored a report showing that farmed salmon had higher concentrations of PCBs -- polychlorinated biphenyls -- than wild salmon.

His work on the Great Lakes could help the EPA determine whether new measures are needed to reduce toxins, said Melissa Hulting, an EPA scientist who manages the data collection program.

"The Great Lakes are pretty sensitive to inputs of these pollutants from the air," Hulting said. "It may take awhile to get the chemicals out of the lakes."

PCBs, an organic compound suspected of causing cancer and other ailments, were once used to cool and lubricate transformers and electrical equipment. PCBs persist for years in the environment and build up in the fatty tissue of fish and mammals, becoming more toxic as they move up the food chain.

The EPA banned the manufacture of PCBs nearly 30 years ago, but it and other chemicals continue to accumulate in the Great Lakes at levels that pose health risks to people.

PCBs move easily between a liquid and a gas, evaporating into the atmosphere from soil and water before falling back to earth and starting the cycle again.

Although the chemicals' levels in the lakes have been declining, they're still high enough to prompt the EPA to advise people to limit consumption of fish caught in all five Great Lakes and many regional waterways.

As part of the study, IU researchers measure PCBs and other toxins in the atmosphere every 12 days at five U.S. locations, including Chicago and Cleveland. Canadian researchers measure sites on lakes Ontario and Huron.

Researchers then analyze the data to determine how much of the compounds ends up in the lakes -- and how much is coming from the lakes, Hites said.

Hites hopes the research explains the unsolved mystery of why levels of PCBs, after dropping steadily for years, suddenly spiked in 1997 and 1998, then dropped again.

"We still don't know why this happened, but we hope the next few years of data will provide us with some answers," he said.

 
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