Hornbuckle and student have a discussion
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PCBs: Dredging Up a Problem

For more than a century, toxins generated by heavy industry settled to the bottom of the Indiana Harbor and Ship Canal (IHSC) in East Chicago, Ind., creating thick sludgy mud that is home to everything from heavy metals to polychlorinated biphenyls (PCBs). The U.S. Army Corps of Engineers has announced plans to dredge the canal, but the plan raises questions for scientists.