After the heavy attention on ocean-based plastic pollution, the focus is moving to plastic pollution in the Great Lakes.

According to a new study by Rochester Institute of Technology researchers, approximately 10,000 metric tons of plastic waste has been entering the Great Lakes every year from the United States and Canada.

The study, "Inventory and transport of plastic debris in the Laurentian Great Lakes," has Matthew Hoffman, assistant professor at RIT's School of Mathematical Sciences as the lead author. It will be published in the coming issue of Marine Pollution Bulletin.

Great Lakes Plastic Pollution

The study employs tools like population dynamics and hydrodynamic modeling to assess the impact and sampled an area stretching from 62 miles or 100 km of the Great Lakes. That was followed by simulating the plastic debris distribution on a five-year period until 2014 for the results.

"This study is the first picture of the true scale of plastic pollution in the Great Lakes," said Hoffman.

They data from the National Oceanic and Atmospheric Administration Great Lakes Coastal Forecast System were used in simulating currents that transport plastic debris across the lakes.

Noting that plastic forms 80 percent of the litter on the shorelines of the Great Lake, the study blames highly populated areas in the United States and Canada for the plastic waste such as Toronto, Chicago, Cleveland, and Detroit.

The danger of plastic being consumed by wildlife and entering the larger food chain is ominous as debris travels differently in the Great Lakes unlike in the ocean.

In oceans, garbage patches are formed but in lakes winds and currents carry them to the shore and they are washed in another state or country.

The study by Hoffman and co-author Eric Hittinger, assistant professor of public policy at RIT highlights the scale of individual pollution in various lakes.

They note Lake Michigan receives half of the total plastic pollution at 5,000 metric tons entering the Great Lakes followed by Lake Erie with 2,500 metric tons and Lake Ontario with 1,400 metric tons. Lake Huron receives 600 metric tons of plastic and Lake Superior gets 32 metric tons of plastic waste every year.

Plastic Pollution Mathematical Modeling 

The RIT study differs from all previous studies with its mathematical modeling in expanding the problem's scope.

Earlier studies were targeting localized concentrations by measuring them through observation of tributaries, open water, and the shorelines.

Environmentalists had been expressing concern over microplastics like beads in face scrubs to fibers from laundry entering the water bodies. All these tiny particles are ingested by animals in marine food chain along with other pollutants.

The RIT study results may come handy in many applications including cleanup efforts, target pollution prevention and gauging flows of plastic pollution on the interstate and international basis.

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