Rivers Flowing Into the Great Lakes Are Teeming with Microplastic Pollution

The minute plastics are in the food chain, and they’re increasingly shown to harm the health of marine animals.

Rivers that flow into the Great Lakes are awash with tiny plastic bits, some barely visible to the human eye but big enough to infiltrate the food chain, according to the largest study of microplastics in rivers to date.

Scientists found the harmful pollutants in every one of the 107 samples taken from 29 rivers across six states, according to research published this week in the journal Environmental Science & Technology.“It’s significant that we found how widespread the plastics were,” said hydrologist Austin Baldwin of the U.S. Geological Survey, the study’s lead author. “We found them not only in really urban watersheds but also agricultural watersheds and even forest-dominated watersheds.”
Concentrations of microplastics were greatest in urban waterways, with Michigan’s Rouge River showing the highest density: 32 particles per cubic meter. Tributaries that passed largely through more natural, forested areas showed smaller concentrations, with the lowest recorded concentration of 0.05 parts per cubic meter in samples from the St. Louis River in Wisconsin.
A growing body of research is showing that ingesting microplastics can harm the health of marine animals. In one recent study, the survival and reproduction rates of European perch dropped after the fish consumed microplastics, which can resemble the prey such species normally feed on. Another report linked microplastic pollution to lower reproduction rates in Pacific oysters.
Research led by environmental chemist Sherri Mason of the State University of New York at Fredonia, a coauthor of the new study, found microplastics in the bellies of 18 fish species in the Great Lakes, including angler favorites such as perch and brown trout.Growing public and regulatory awareness of the issue has focused on microbeads: minuscule polymer balls added to personal care products to help scrub off dead skin cells or whiten teeth. Mason’s earlier research proved that microplastic pollution was endemic throughout the Great Lakes and helped spur a federal ban on microbeads in personal care products and cosmetics; the ban takes effect in 2017.

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