University of Iowa researchers have found high levels of toxic polychlorinated biphenyls (PCBs) in the deep sediments lining the Indiana Harbor and Ship Canal (IHSC) in East Chicago, Ind. Scientists say the discovery is cause for concern because the IHSC is scheduled to be dredged in spring 2012 to maintain proper depth for ship traffic in this heavily industrialized area of southern Lake Michigan.
The study, published online in the journal Chemosphere on Sept. 6, builds upon a previous UI study that found the release of PCBs from the sediment floor to the water above, and then, to the air. This time, scientists drilled down into the floor of the canal and discovered that the concentration of PCBs buried within the sediment is even higher.
"We found that the deeper you go, the more toxic it is," said Andres Martinez, a UI postdoctoral scholar in civil and environmental engineering and lead author of the study. "Dredging the IHSC has the potential to expose these more toxic sediments."
PCBs can enter the human body by eating or drinking contaminated food, through the air we breathe, or by skin contact. According to the Environmental Protection Agency (EPA), these compounds have been shown to cause cancer, along with a variety of other adverse health effects on the body's immune, reproductive, nervous and endocrine systems.
"This finding is significant because it demonstrates that the concentration of toxic chemicals below the surface of the canal floor is quite high," said Keri Hornbuckle, professor of civil and environmental engineering in the UI College of Engineering and coauthor of the study. "We need to get this information out, because the level of pollutants underneath the sediment has never been reported."
PCBs were widely used as coolants in electrical transformers and in a wide variety of products, ranging from waterproofing compounds to paints and pesticides. They were manufactured from 1929 until th
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University of Iowa Health Care