IU scientists study toxins in Great
Published November 28th, 2004
BLOOMINGTON, Ind. -- 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
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
"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
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
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,"