BROWN: Trashing the Great Lakes: Plastic pollution abounds

Some of the most iconic images of marine litter involve plastic. Picture a turtle caught in plastic six-pack rings, a tree’s branches draped with shopping bags, or a highway median full of empty bottles.
Mar 21, 2014

However, an emerging Great Lakes plastic problem is much less photogenic. In fact, it is microscopic.

A recent study published in Marine Pollution Bulletin revealed tiny plastic particles floating throughout the surface water of the Great Lakes. The published research highlights the team’s work in Lake Superior, Lake Huron and Lake Erie. The team, led by Marcus Eriksen of the 5 Gyres Institute, is currently studying their samples from Lake Michigan and Lake Ontario.

Twenty of 21 collected samples contained plastic. Lake Erie accounted for 90 percent of the total volume of plastic collected, possibly due to the fact that Lake Erie is surrounded by three major urban centers — Detroit, Cleveland and Buffalo.

The average abundance was 43,157 plastic particles per square kilometer, with 80 percent of the particles ranging from 1/3 to 1 millimeter in size. 

With Chicago and Milwaukee in the Lake Michigan watershed, will Lake Michigan be inundated with plastic?  

Interestingly, the research team initially misidentified coal fly ash as plastic particles. In fact, eight of the 21 samples were comprised of as much as 20 percent coal ash.

Fly ash is a product of coal combustion. Some coal ash is released into the atmosphere; some is captured and stored inadequately; and some is reused in cement, concrete and asphalt where it may enter water bodies through stormwater. Coal ash can contain numerous toxic chemicals, and the incidental discovery of so much fly ash is troubling in its own right.  

Right now, there are more questions than answers. How does plastic enter the Great Lakes? What types of plastic products are of greatest concern? How does it move around? To what extent does it naturally degrade and what ecological harms does it pose?

Larger pieces of plastic can fatally entangle or suffocate marine species and ingestion can impede organ function. Microplastics can become part of the diet for marine life. Plastics absorb certain toxins and can accumulate in marine life when eaten.

Researchers have discovered that even small invertebrates such as mussels ingest microplastic, potentially impacting every species up the food chain. 

The strategies for studying plastic pollution are still being developed. Some microplastics float, some sink, and some linger somewhere between the sediment and the surface. More study is needed on how each kind of plastic behaves in the water column; currents and water temperatures can play a role as well.

Researchers haven’t yet identified the main sources of plastic pollution in the Great Lakes. The leading theories are that littering, inadequate waste management, stormwater and combined sewer overflows contribute the most.

The small particles of plastic collected during the study in the Great Lakes are believed to be microbeads, which typically cannot be collected in wastewater treatment.

As more is learned about the issue, attention should turn to solutions. Early options being discussed include increasing the recycling rate, tightening solid and liquid waste management practices, altering plastic production, and reducing the utilization of plastic. 

Once a national leader, Michigan now has an abysmal statewide recycling rate estimated by the state Department of Environmental Quality to be about 14.5 percent. 

Biodegradable plastic is an alternative to petroleum-based plastics, but studies show that many existing biodegradable plastics only compost in the right conditions — conditions that are not present in marine environments.

The 5 Gyres team believes that microbeads found in personal care products, like face wash and shampoo, are a potential source. The Great Lakes’ plastic samples are of similar shape, size, color and composition. Several large companies have agreed to phase them out. New York and California have developed legislation to prohibit the sale of products containing plastic microbeads.

Consumers can also choose products that do not contain plastic microbeads — and, in fact, there are products that still offer the exfoliating benefit of the beads, but with natural products. Consumers willing to read the ingredients on their personal care products should look for these four wordy types of plastic: polyethylene (PE), polypropylene (PP), poly(methyl methacrylate) (PMMA) or polyethylene terephthalate (PET).

Plastics are intended to be durable. While the production and use of plastic products continues to grow, the rate of recycling remains dismally low.

Documentaries like “Trashed” are exposing the global problem of plastic pollution in the marine environment, but the Great Lakes are a globally unique freshwater ecosystem. Microplastics require significantly more regional research and problem solving. 

The West Michigan Environmental Action Council looks forward to the results of Mr. Eriksen’s team’s work in Lake Michigan and Lake Ontario, and we call on other scientists and research institutions to take up this compelling issue.   

— By Becky Brown, the water programs outreach coordinator for the West Michigan Environmental Action Council.

Comments

nocchipi

"Once a national leader, Michigan now has an abysmal statewide recycling rate estimated by the state Department of Environmental Quality to be about 14.5 percent." - Michigan can do much better on recycling.

Interestedreader

California has outlawed plastic bags,only paper at the stores,perhaps an issue for MI

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