"Protecting the Great Lakes' water quality is an important goal in itself," Hites said. "The lessons we learn from IADN, however, will relate to the behavior of contaminants around the world."
Discoveries by IADN scientists and others have helped reduce toxins in and around the Great Lakes, and improved the quality and safety of the lakes in recent decades.
PCBs are semi-volatile, which means the toxins can easily alternate between liquid and gaseous states. Hites and other environmental scientists have found that some of these airborne PCBs waft toward the Great Lakes and dissolve into them.
"Input from the air is one of the main ways that these chemicals can get into the Great Lakes," said EPA scientist and IADN Program Manager Melissa Hulting. "PCBs do not break down easily and can remain in the environment long after they were initially used or released. Their persistence also allows PCBs to travel long distances, even around the globe, so the PCBs that get into the Great Lakes can be from nearby or very far away."
A previous study by Hites and Basu reported increased lake PCB levels at Sturgeon Point, N. Y., when winds blew southward from Buffalo, about 12 miles away.
A broader study of other locations around the Great Lakes has corroborated this "urban effect" in PCB levels. For example, PCB concentrations at the most urbanized study site, downtown Chicago (1,000 picograms per cubic meter of air), are about 10 times higher than PCB levels at the decidedly less urbanized study site at Eagle Harbor on Michigan's Upper Peninsula (100 picograms per cubic meter of air).
Air, water and precipitation samples are collected at five master sites and 10 satellite sites in the United States and Canada. Some of the study sites are located in or near the cities of Chicago; Detroit; Cleveland; Buf
Contact: David Bricker