Plastic polluting the Great Lakes
A second summer research tour of the Great Lakes has confirmed what the first one found — a wealth of tiny plastic particles is polluting the water.
Mary Balcer, director of the Lake Superior Research Institute at UWS, who has studied more traditional Great Lakes threats such as zebra mussels, said plastics are a new culprit on the list of Great Lakes ecological troubles.
“The accumulation of plastic particles is a great threat to our natural ecosystem and to the humans who use Lake Superior for our drinking water supply,” Balcer said Thursday.
Lorena Rios-Mendoza, assistant professor of chemistry at the University of
Wisconsin-Superior, said this summer’s efforts found small concentrations of plastic particles in Lake Michigan and Lake Ontario. Last year she found them in Superior, Erie and Huron.
So far, after two years of research, Lake Erie seems to hold the highest concentrations of plastics, she said, probably because the particles usually float. downstream from the upper lakes.
But Rios-Mendoza said Thursday that plastic particles have been found in all of the Great Lakes and Lake St. Clair. And she said that researchers also found them this summer in Lake Superior sediment, meaning they are not just floating on the surface of the giant lake.
“It was very shallow where they were found, but they were in the sediment,” she said.
Fresh off the research boat, Rios-Mendoza presented her preliminary findings Thursday at a media briefing at UWS.
The researchers drag fine-mesh nets across the surface of lakes. If you weren’t looking for them, scientists say, you probably wouldn’t notice how much plastic there was.
So far, Rios-Mendoza’s hypothesis is that the plastic in the Great Lakes starts small, possibly as scrubbing beads in household or beauty products, facial scrubs and even some toothpaste.
The particles are tiny enough to slip through the screens at wastewater treatment plants and then start their journey bobbing with the wind and currents across the Great Lakes.
Not only is the plastic itself an issue, she noted, but research has found that plastic can absorb persistent toxic chemicals, some of them known endocrine disrupters. So the floating plastic beads act like tiny, toxic sponges. That’s bad because the articles are just the size to be confused as food for small fish, she noted.
Rios-Mendoza wasn’t surprised to find plastic building up in the Great Lakes ecosystem. She had studied plastics in the Pacific and Atlantic Oceans since 2003, and she came to Wisconsin and UWS in 2010 expecting to find it here.
What surprised her last summer, her first year of field work on the Great Lakes, was the size of the plastic particles she found — tiny, generally about the size of a grain of sand, or 1 millimeter or less in diameter. Some of them can be seen only under a microscope.
In the ocean, by contrast, the plastic particles found, even after degrading in the environment for years, are generally much larger.
Yet, even though they are smaller in the Great Lakes, the number of particles found in some Lake Erie samples was greater than the volume of plastics found in ocean samples. Researchers counted 1.7 million plastic particles found in their Lake Erie nets alone.
The researcher said her work is raising more questions, ones outside of her field of expertise, on the impact the plastic and toxins might have on fish and the animals and people who eat fish.
Rios-Mendoza isn’t shy about jumping from researcher to advocate for the environment. On Thursday she reminded people of the three R’s of sustainability — reduce, reuse and recycle — when it comes to plastics. Keeping plastic out of the environment is key, she said.
“But I have a fourth one: Refuse,” she said. “If someone offers you a plastic bag for your sandwich, say no. … People ask, ‘Where this does come from?’ We are the source.”
She urged everyone to avoid using products that contain any kind of polymer or plastic ingredients, sometimes called microbits, on ingredient lists. She also urged people to avoid any beauty or health-care products with polypropylene and polyethylene as ingredients.
Some companies, including Procter & Gamble and Johnson & Johnson, have said they will phase out use of plastic particles.
Rios-Mendoza is working with 5 Gyres Institute, a Los Angeles-based nonprofit. She first started her ocean plastics research in 2003 at the University of the Pacific working with support of Algalita Marine Research Foundation in Long Beach, Calif.
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