By Melissa Breyer / Source: TreeHugger


Lake Michigan alone receives the equivalent of 100 Olympic-sized pools full of plastic bottles each year.

Welcome to the latest edition of Planet Plastic, in which we find that not only are our oceans rife with plastic pollution, but our greatest of lakes suffer the indignity as well.

Such is the conclusion of a new study from the Rochester Institute of Technology that inventories and tracks high concentrations of plastic in the Great Lakes. And while the news is grim, it will hopefully prove helpful with future cleanup efforts and targeting pollution prevention.

The researchers found that around 10,000 metric tons (22 million pounds) of plastic debris enter the Great Lakes annually, the plastic pollution comes courtesy of both the United States and Canada.

“This study is the first picture of the true scale of plastic pollution in the Great Lakes,” says Matthew Hoffman, assistant professor in RIT’s School of Mathematical Sciences. Hoffman used computer simulations to follow the volume of plastic debris moving across state and international boundaries, from Illinois to Michigan and from Canada to the United States, according to RIT.

Along with co-author Eric Hittinger, Hoffman found that 5,000 metrics tons per year (half of the plastic pollution entering the Great Lakes in all) is delivered to Lake Michigan; Lake Erie is the recipient of 2,500 metric tons and Lake Ontario gets 1,400 metric tons. Lake Huron ends up with 600 metric tons of plastic and Lake Superior receives 32 metric tons per year.

For an easier way to understand that, think of it this way: The plastic pollution in Lake Michigan is about the equivalent of 100 Olympic-sized pools full of plastic bottles. Lake Ontario’s plastic chaos is comparable to 28 Olympic-sized pools full of plastic bottles.

The new study used the magic of mathematical modeling for a more comprehensive scope of the plastic pollution in the lakes. As RIT notes, “the inventory gives full mass estimates on the entire connected lake system and maps plastic debris moving between lakes and across interstate and international borders. The results provide environmentally realistic concentrations of plastic in the Great Lakes.”

And interestingly, the study finds that rather than congregating into patches like plastic does in the ocean, in the lakes the plastic is moved by wind and currents and mostly pushed ashore, often in another state or country than where it originated. Plastic accounts for somewhere around 80 percent of the litter on the shorelines of the Great Lakes.

Also notable is that while the big cities – Chicago, Toronto, Cleveland and Detroit – are the primary source of plastic pollution in the Great Lakes, they end up with less litter on their shorelines than they produce.

“Most of the particles from Chicago and Milwaukee end up accumulating on the eastern shores of Lake Michigan, while the particles from Detroit and Cleveland end up along the southern coast of the eastern basin of Lake Erie,” Hoffman says. “Particles released from Toronto appear to accumulate on the southern coast of Lake Ontario, including around Rochester and Sodus Bay.”

Read more @ TreeHugger