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Researchers Trawl Lake Michigan for Microplastics

Researchers begin trawling for microplastics on Lake Michigan aboard the Flagship Niagara. Photo courtesy of 5Gyres Institute.

To paraphrase a line from the classic 1967 move The Graduate, Sherry “Sam” Mason, associate professor of chemistry at the State University of New York – Fredonia, would like to say one word to you. Just one word. Microplastics.

Not that she wants you to consider a career in microplastics, but she would like you to consider microplastics as the latest source of pollution in the Great Lakes.

For the past two summers, Mason and a team of researchers with the Los Angeles-based nonprofit 5 Gyres Institute have been plying the waters of the Great Lakes aboard the Flagship Niagara, one of the tall ships in this year’s Baylake Bank Tall Ships Festival, while trawling with a fine-meshed net for microplastics that have been collecting in the lakes. Last year she and the team collected samples from Lakes Superior, Erie and Huron. Earlier this summer samples were taken from Lake Ontario, and last week the team began sampling the waters of Lake Michigan.

“We’ll be out there three weeks, trawling Lake Michigan for microplastics,” she said recently by telephone. “We have a big net that skims the surface of the water. Anything that’s bigger than 1/3 of a millimeter will be contained in the end of the net.”

Mason said going into the survey last year, researchers expected to find plastic waste in the Great Lakes, just as massive amounts of plastic have been found in the world’s oceans. The “trash vortex” in the North Pacific occupies a space similar in size to the state of Texas.

“We anticipated finding plastic because of everything we find in the oceans, and, essentially, the Great Lakes are upstream from the oceans, so if you find it in the oceans, you’ll find it in the Great Lakes,” she said, but adding that they were surprised by the type of plastic they did find.

“We expected to find bigger pieces of plastic,” she said. “Instead, what we found were smaller bits. The biggest size were particles between a third of a millimeter and a millimeter in size. These are classified as microplastics. Predominantly, those microplastics seem to be microbeads. About 70 percent.”

The perfectly round beads of polyethylene are from face washes, body scrubs, toothpastes and other personal care products that contain polyethylene “scrubbing particles.”

“The main source is these personal care products. That is one source we can identify, these face washes and body scrubs, toothpaste that contain these microbeads as one of their components,” Mason said.

Dr. Lorena Rios-Mendoza, assistant professor in chemistry at the University of Wisconsin – Superior, was also involved in the sampling expedition last summer. Later this month she will return to Lake Superior for another trawl for plastics.

“I am working with the analysis of persistent organic pollutants, as PCBs (polychlorinated biphenyls), PAHs (polycyclic aromatic hydrocarbons), and organochlorine pesticides, such as DDTs,” she said. “My experience in the analysis of POPs (persistent organic pollutants) absorbed onto plastic debris in the ocean suggests that plastic debris is behaving as a new form of sediments. This means plastic debris is a new source of POPs to aquatic organisms. I found that samples from Lake Erie absorb and concentrate PAHs, PCBs, and I do not know yet the results for pesticides.”

That means the small plastic fragments containing these toxins and floating in the water could easily be confused as food and ingested by fish and water birds.

“We analyzed 110 samples of stomachs of fish from Lake Superior and we found in 20 samples microscopic fiber of plastics,” Rios-Mendoza said. “Plastics are practically indestructible in any reasonable scale time, so please recycle, reuse, reduce and refuse to use plastic. Most the times plastics finish in the ocean, lakes or in the stomachs of organisms. Remember, we need to stop the source and we are the source!”

Mason agrees.

“I think any plastic we’re finding in the Great Lakes is an issue. It shouldn’t be there. When we go looking for places that can support life, what do we look for, water because water is the essence of life. It’s kind of the basic necessity for any kind of living organism to survive. And we’re polluting that with something that is synthetic and can’t be biodegraded and has known health impacts.

We have the largest freshwater ecosystem in the world, so any piece of plastic we find in there, I have issues with. That’s part of why I do what I do. Any plastic we’re finding in the lake, ultimately comes from us. Each of us, therefore, as an individual person can dramatically effect the health of our lake by thinking of the choices we make on a day-to-day basis in terms of what we buy and what we consume, and how we dispose of it.”