Michigan's Kalamazoo River is polluted by polychlorinated biphenyls (PCBs), highly toxic chemicals banned in the 1970s.

CNN: Pregnant women should follow guidelines on eating fish

There was another class of hazardous chemical present: polychlorinated biphenyls (PCBs).

CNN: THE GREAT DIOXIN SCARE

Worse still, some of those fish are full of polychlorinated biphenyls (PCBs), which at worst, cause cancer and at best wreck humans' immune, reproductive, nervous and endocrine systems.

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