The Great Lakes may be developing a giant garbage patch similar to the one in the Pacific Ocean.
The largest group of freshwater lakes in the world is being filled with plastic debris that is amassing in certain locations.
"The massive production of plastic and inadequate disposal has made plastic debris an important and constant pollutant on beaches and in oceans around the world, and the Great Lakes are not an exception," said lead author Lorena M. Rios Mendoza of the University of Wisconsin-Superior.
Most of the debris is made up of tiny particles that have broken up, making them difficult to notice.
In Lake Erie, researchers found between 1500 to 1.7 million particles per square mile.
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"The main problem with these plastic sizes is its accessibility to freshwater organisms that can be easily confused as natural food and the total surface area for adsorption of toxins and pseudo-estrogens increases significantly," said Rios in a statement.
The problem may be worse in the Great Lakes than in the oceans.
Researchers found that the number of microparticles in the Great Lakes was 24 percent higher than in the Southern Atlantic Ocean.
The amount of plastic produced has increased 500 percent in the last 30 years.
Plastic, in various forms, is responsible for 80 to 90 percent of ocean pollution.