How Big is the Plastics Problem in the Great Lakes?

By Dave Long

Many people realize the world has a serious problem with plastic pollution. The crisis has been featured on television, in movies and articles in National Geographic and many other publications. For example, the news has featured the Great Pacific Garbage Patch, which has been estimated to be the size of the state of Texas.

The Great Pacific Garbage Patch is largely made up of plastics. It contains single-use plastic waste, old fishing nets and buoys, and many other plastics from around the earth that have been caught up in the ocean currents. There have been several efforts to collect the plastics and reduce the volume of the garbage patch, but these efforts have not been very successful. The sad fact is three other garbage patches have been identified in the oceans, and many small islands have been destroyed by plastic waste.

The Great Lakes contain approximately 20% of the world’s surface fresh water. Compared to ocean plastics, not much has been reported about the amount of plastics in the Great Lakes. Based on the 2016 US Geological Survey (USGS) reports, significant volumes of plastics enter the Great Lakes every year, and they are not going away. The United States and Canada together discard 22 million pounds of plastic into the waters of the Great Lakes each year, according to a 2016 Rochester Institute of Technology (RIT) study. Much of it washes up along the shores, accounting for 80 percent of the litter found there. Researchers report that Chicago, Toronto, Cleveland, and Detroit are the worst contributors to plastic pollution. Half of the plastic dumped into the Great Lakes—11 million pounds—goes into Lake Michigan. Lake Erie places second, receiving 5.5 million pounds. Lake Ontario gets 3 million pounds of plastic waste a year, with Lake Huron and Lake Superior receiving smaller amounts.

Plastic pollution in Lake Michigan represents approximately the equivalent of 100 Olympic-sized pools full of plastic bottles dumped into the lake every year. Most of the particles from Chicago and Milwaukee end up accumulating on the eastern shores of Lake Michigan, while the particles from Detroit and Cleveland end up along the southern coast of the eastern basin of Lake Erie.

According to an article in the journal Environmental Science & Technology, tiny pieces of harmful plastic called microplastics are prevalent in many rivers that flow into the Great Lakes. Results are also illustrated on a new USGS microplastics website. This study characterized the quantity, size, and shapes of floating micro- and macroplastics in 29 Great Lakes tributaries in six states with adjacent land being forested, farmland, and urban areas. Water contributions came primarily from runoff and wastewater effluent. Rivers ran through areas with varied population densities and hydrologic conditions. Plastic particles were sorted by size, counted, and categorized.

Microplastics were found in all 107 samples, with a maximum concentration of 32 particles/m³ and a median of 1.9 particles/m³. Ninety-eight percent of sampled plastic particles were less than 4.75 millimeters in diameter and therefore considered microplastics. Urban watersheds had the highest concentrations of microplastics, but microplastics were also present in streams in forested and agricultural areas.

In summary, the USGS found 12% of fish from the Great Lakes contained plastic particles, 1,285 plastic particles in a square foot of river sediment, and 112,000 particles per square mile of Great Lakes water.

Where do microplastics come from? One source is photodegradation and/or mechanical breakdown of larger items, such as Styrofoam, plastic bags, bottles, wrappers, cigarette butts, and tires. As these plastics are exposed to sunlight, wind, waves, and water currents, larger pieces get smaller and smaller. Unfortunately, filters from cigarette butts are one of the most common types of plastic pollution found on a beach and lake bottom. Many smokers simply flick their cigarette butts on the ground, or worse, in the lakes. Some 95% of cigarette filters are made of tightly packed white cellulose acetate (a plastic). These small fibers break down into smaller and smaller particles, but it takes hundreds of years for cigarette filters to degrade.

Another source of microplastics, a subgroup called microfiber, comes from washing machines. Mark Browne’s research demonstrated a large percentage of the microplastic pollution comes from synthetic fabrics like nylon and acrylic fabrics. Patagonia, in its self-funded study by the Bren School of Environmental Science and Management, analyzed water and sediment samples from around the world and concluded “Microfibers are ubiquitous in the aquatic environment.” Patagonia in its own laundry study verified that large quantities of microfibers were released when washing synthetic garments, especially fleece. They also verified that wastewater treatment plants receive large quantities of microfibers and the majority of the microfibers pass through wastewater treatment plants because they are too small for treatment plants to filter.

Knowing that aquatic wildlife eat these microfibers is one thing; but seeing the impact on an individual fish brings this crisis to life—or rather, death. Sherri Mason, a professor of environmental chemistry at the State University of New York at Fredonia, is an expert in plastic pollution, having studied its impact on the Great Lakes ecosystem for several years. Through Mason’s research, she has seen the significant impact of the food chain in the Great Lakes. Cutting open fish, she was alarmed at what she found.  The body cavity of the fish was filled with synthetic fibers. Through the microscope, they seemed to be weaving themselves into the gastrointestinal tract.

What are the known risks from microplastics? We know that microplastics and microfibers can be harmful to wildlife. They are often ingested by birds, fish, oysters, mussels, and zooplankton. Ingestion is often a physical hazard blocking the intestine, interfering with reproduction, and even causing death.

They can also be a toxic hazard. Plastic particles can accumulate contaminants such polychlorinated organics, polycyclic hydrocarbons, and pesticides, which can be associated with endocrine disruption and cancer. These contaminants can accumulate within the food chain and end up in the fish we eat. Microfibers from garments have often been treated with toxic chemicals such as formaldehyde, brominated flame retardants and fluorinated fabric treatments. In a 2012 study, Mason found Lake Erie had higher concentrations of microplastics than any other body of water on Earth. Absorbed on these tiny pieces of plastic they found pollutants, such as DDT, polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), too small for treatment plants to filter out.

Are those living around the Great Lakes ingesting microplastics and microfibers? If humans are eating fish and other wildlife from the Great Lakes, they are likely consuming microplastics. Your favorite beer, if manufactured with Great Lakes water, likely contains microplastics or microfibers. Microfibers have been found in bottled water derived from the Great Lakes and microplastics and microfibers have been found in small quantities in some public water systems. Unfortunately, to date, very little research has been conducted on the effects of microplastics being ingested by humans. Much research will be required to determine the health or physical impacts to human ingestion of microfibers and microplastics.

David Long is the founder of Environmental Sustainability Solutions, LLC (ESS) that provides consulting services for environmental, sustainability. He will address potential methods to reduce the volume of plastics entering the Great Lakes and its tributaries in a future article.