Invasive species reintroducing toxic, possibly cancer-causing, chemicals to Green Bay food web

"Two invasive species—the quagga mussel and round goby—can allow a group of toxic chemicals deposited more than 45 years ago to reenter the food web, passing them to predatory fish and possibly people," said a study published in the Journal of Great Lakes Research, Holly Drankhan reports for the Great Lakes Echo, a service of the Center for Environmental Journalism at Michigan State University. (Wisconsin Department of Natural Resrouces photo: Adult round gobies eat quagga mussels and may reintroduce PCBs to predatory fish)

Polychlorinated biphenyls (PCB), which the Environmental Protection Agency says can potentially cause cancer and may harm reproductive, neurological and immune systems, were discharged into the the Lower Fox River in northeastern Wisconsin from 1954 to 1971 by manufacturers of carbonless copy paper, Drankhan writes. "The river flows north from Lake Winnebago and discharges into Lake Michigan’s Green Bay."

Study author Kimberly Gray, of Northwestern University, said "the two invasive species are relatively stationary and reside in the lowest portion of the water column," Drankhan writes. "They move a large segment of the aquatic food web’s energy to the bottom of Green Bay, where PCBs are most concentrated."

"Mussels can filter about a liter of water a day, said Bob Wakeman, Wisconsin Department of Natural Resources water resources management specialist," Drankhan writes. "Adult round gobies in turn eat quagga mussels. This makes both invasive species capable of refocusing PCBs and introducing them to species higher up on the food chain—like the fish that people catch and eat." (Read more)