Plastic pollutes the Great Lakes in concentrations higher than any other body of water on Earth, concluded a recent study conducted by the State University of New York.
The first project to survey plastic pollution in the Lakes, students and faculty from the University spent the summer sailing Lake Superior, Lake Huron and Lake Erie collecting samples with a trolling net.
“We had two samples in Lake Erie that we just kept going back and rechecking the data, because the count, the number of plastic particles in the sample, was three times greater than any sample collected anywhere in the entire world,” said Sherri Mason, the project leader and SUNY chemistry professor.
James Dau, writing for the Great Lakes Echo, reports:
They found the least plastic in Lake Superior, with the concentrations increasing as they sailed south. That’s because water flows south from Lake Superior through Lake Huron and into lakes Erie and Ontario. The water carries plastics from one lake to the next, compounding the concentration each time, Mason said.
The net's mesh was a scant 333 micrometers (0.013 inch) wide allowing the researchers to capture the most minute microplastics found in the water. Their findings were puzzling, said Mason:
The reigning kind of thinking is that plastic moves from the land to the ocean through rivers and lakes, and that it gets smaller as it goes through erosion.
We thought we would find bigger pieces in the lakes than in the ocean, but we didn’t really. The vast majority of what we found was really, really small.
Plastic that small does not make it all the way to the ocean. Mason added, "somewhere in between there it disappears, and we want to know where it’s going.”
Scientists suspect that the microplastics are either washing up on beaches or becoming absorbed into the food chain via microorganisms or fish, which presents a real threat to human health, says Mason. "The fish may not immediately die, but they could remain toxic, and that’s really scary. If the plastics and chemicals are moving into the food chain, they’re moving into us.”
SUNY's study was done in partnership with the Los Angeles-based 5 Gyres Institute as part of a larger global effort to understand the origin and prevalence of plastic pollution in water.