Researchers focus on Great Lakes pollution

BLOOMFIELD HILLS, MICH. — Microplastic particles, not just in the form of tiny beads but fibers and fragments, too, are polluting the Great Lakes and launching new areas of study for scientists.

From face scrubs to fleece jackets, the list of threats to the five lakes, which hold about 20 percent of the earth's surface freshwater, is growing. The latest concerns are polymer particles under 5 millimeters in size, and there are calls to start scrutinizing water samples for nanoplastics under 0.33 mm.

Overall, the Great Lakes studies to date just scratch the surface of the problems polymers could be posing, according to Jennifer Daley, a research fellow at the University of Michigan.

“What we saw most were polyethylene, polypropylene or nylons, which makes sense because these dominate plastics production,” Daley said during a March 6 lecture at the Cranbrook Institute of Science in Bloomfield Hills.

Cranbrook has an exhibit called “Plastic Waters: From the Great Lakes to the Oceans,” which is being presented by the Alliance for the Great Lakes and the California-based 5 Gyres Institute.

Known for tracking an estimated 260,000 metric tons of floating debris (the weight of an estimated 5.2 billion plastic particles) that accumulated in five ocean zones, 5 Gyres has brought attention to the derelict fishing nets, shopping bags, action figures, bottle caps, flip flops, pacifiers and more swirling about the Pacific, Atlantic and Indian oceans.

Daley said the soupy salt waters peppered with macroplastics — as high as 10 particles per liter in one study of the northeast Pacific — gave rise to questions about synthetic threats to other waterways.

“In the last few years people have been asking: What about fresh water systems, particularly the Great Lakes,” Daley said. “They're host to 30 million people, 21 percent of our fresh water, and $4 billion in fishing alone. When you have that many people on a system, there are bound to be stressors. The Great Lakes are impacted by everything from habitat alteration and invasive species to pesticides and litter. Where does plastic pollution fit when it comes to Great Lakes stressors?”

The answers are only starting to come into focus on microscope slides.

Too much fiber

One recent threat to make waves in the mass media came in January with coverage of water samples taken in 2013 from Lake Michigan. Scientists sounded the alarm that 12 percent of the debris consisted of microfibers.

“To be honest, most microfibers are probably coming from our washing machines,” Daley said of fabrics made from plastics like polyester and nylon.

Microfibers also were found in the gastrointestinal tracts of some fish and a double-crested cormorant, which eats fish.

Another field study, this time of 100 fish by University of Michigan researchers, showed similar results for the five species of fish tested.

“While they didn't find microbeads, they did find fibers in 11 to 36 percent of the fish,” Daley said.

Scientists now are trying to determine the risks posed by the fine fibers on aquatic life along with the effects from highly publicized microbeads and small fragments from degrading macroplastics.

“This is an area where we really need to study to understand which organisms are coming into contact the most with microplastics,” Daley said. “This could be ingestion by zoo plankton that swim across the waters or ingestion by fishes. In terms of effects, we don't know at this point but these are some areas we think could be a concern if indeed organisms are taking up microplastics to a significant degree.”

Energy reduction

One of the 5 Gyres exhibit pieces at Cranbrook shows a picture of a gutted fish next to about 15 little shards of blue, yellow, white, black, beige and brown plastic. The caption asks: What's in your sushi?

Scientists have a lot of other questions about the effects of microplastic litter in the marine environment.

“This is an area we're getting into now,” Daley said. “We're early in the stages of understanding the impact on organisms. We know microplastics are small enough to be taken up by a number of organisms across all trophic levels.”

A trophic level is the position an organism occupies in a food chain. Daley said in 2013, scientists saw the uptake of microplastics in one of the bottom feeders change the energy reserve of marine worms.

“There was a 30 percent decrease in energy reserves in worms from a 1 percent by weight microplastics ingestion,” she said. “What that shows is there might be an issue with starvation if there's that substantial of a decrease in energy reserves. We need field validations to see what this looks like at environmental concentrations.”

As a physical contaminant of organisms, Daley showed a slide that says ingested microplastics could have both behavioral and morphological effects. They could hinder mobility, reduce vigor, block intestines and gastric enzyme secretions, diminish feeding stimulus, hamper breathing and delay ovulation.

Then, there are the chemical contaminants. Some research suggests aquatic organisms also are exposed to the chemicals associated with plastics.

“This is all really early research and we need to do more work,” Daley said.

Beads, fragments

Microplastics, which are technically 0.33 to 5 millimeters, find their way into the waterways from wind, storm runoff, boats, wastewater treatment plants, and accidental and intentional dumping. The plastic bits float on the surface, are suspended in the water column, sink to bottom sediment, and wash up on beaches.

Most of the marine litter is plastic fragments from larger items that degraded into smaller pieces because of weathering, mechanical breakdowns and microbes.

Sarah Neville, stewardship coordinator for the Alliance for the Great Lakes, said even the adopt-a-beach cleanups are getting more challenging because of teeny bits of plastic. Still, 14,500 volunteers in the eight Great Lakes states removed 51,797 pounds of trash from some 350 coastal areas in 2014.

“The numbers are really just staggering,” Neville said. “Unlike the river cleanups, we don't find refrigerators and tires. These are small, small pieces of plastic that people are picking up and they are adding up to these enormous values. … Plastic pollution is so problematic because this might break down into smaller pieces but it's not something that's going away. We're finding it in wildlife and we know it's negatively affecting the environment.”

Daley said the first and only published peer-reviewed article about microplastics in the Great Lakes was released in 2013. Tests were done on 21 water samples taken from Lakes Erie, Huron and Superior during a 2012 expedition led by Marcus Eriksen, researcher and co-founder of 5 Gyres Institute.

The researchers found that the lakes are teeming with debris, such as glass, metal and aluminum silicate from coal ash, and they estimated 60 to 80 percent of the marine pollution is plastic. All but one of the 21 samples collected by net tows contained plastic with an average abundance of 43,157 plastic parts per kilometer squared. Particle counts varied from 450 to more than 450,000 parts per kilometer squared; the size range of 0.35 to 0.99 mm accounted for 81 percent of the total.

The highest concentrations were found in Lake Erie near Buffalo, N.Y. Two samples near this city contained 85 percent of all the microplastic particles collected, including many green, blue and purple colored spheres consistent with microbeads found in facial cleansers. One sample contained 1,101 plastic particles, or 463,423 particles per kilometer squared, which was the highest count for one of the 60-minute tows.

“That follows suit with Lake Erie being a heavily impacted system,” Daley said.

Also, Lake Superior showed slightly higher particle counts than Lake Huron but that could be because water samples were taken closer to the shore, which is closer to sources of pollution.

Daley pointed to another study that looked at microbead density in bottom sediments of the St. Lawrence River, which connects the Great Lakes and the Atlantic Ocean.

“It's a really important water body,” Daley said, noting one sample contained 136,000 microbeads in a meter-squared area. “I'm not sure what was going on here. Was it a spill? We really don't know. It's another article showing microplastics in the Great Lakes and that we need to do more research in this area.”

What's next?

The findings from the expedition Erickson led brought about calls to ban microbeads from personal care products. Illinois was the first to outlaw them in June 2014, banning the manufacture of personal care products containing microbeads by the end of 2017 and the sale of those personal care products by the end of 2018.

New Jersey followed and similar proposals are pending in New York, Minnesota, Wisconsin, Indiana, Michigan, Colorado, California, Vermont, Connecticut and other states as well as at the federal level.

Some businesses in the plastics industry also are scrambling to develop biodegradable ingredients for personal care products. On March 5, biomaterials company Metabolix announced it is partnering with Honeywell to create a biobased microbead, perhaps with Mirel PHA biopolymers, which tests show are similar to cellulose and paper.

Daley said marine scientists also want to delve deeper into questions about new life forms in microbial communities growing on the surfaces of plastics — so-called plastispheres — and whether the particles' movement could “introduce alien species” to other areas. In addition, they wonder if microplastics are interacting with chemicals in the environment, like legacy contaminants such as PCBs.

“At this point the literature tells us that plastics can absorb and concentrate pollutants,” Daley said. “Degraded plastics can leach chemical additives — bisphenol A, phthalates, flame retardants. The next question is what does it mean to secondary impacts to organisms compared to other sources?”

And, how about other threats?

“Nobody is really looking at nanoplastics,” Daley said. “A number of articles have suggested we look at them. We should start thinking about all plastics — not just stopping at 0.33 mm but also looking at the really small-ranged microplastics.”

The University of Michigan has formed a research platform with eco-toxicologists, chemists, biologists and social scientists to address some questions about microplastics in the Great Lakes. Daley said they will study food dynamics, physical characteristics of the plastics, source tracking, environmental health and best methods for sampling microbeads.

“With young science it's beneficial to look at other focus areas to do our research and some of those directions I can see in the future would be understanding the types of microplastic that are the biggest current threat,” Daley said. “Is it microbeads, microfibers, fragments? What is the risk of exposure to Great Lakes organisms and what does realistic environmental concentrations mean?”