Microplastics Invading the Food Chain

Photo: Possible microplastic mass in lower segment of Copepod

By David Long

The Great Lakes face many challenges. Some are well-known, such as Asian carp, but some are almost invisible, such as microplastics.

Small plastic detritus, termed “microplastics” or “microfibers,” are a widespread contaminant in aquatic ecosystems including the Great Lakes.

Research reported in Environmental Science and Technology suggests that marine microplastic debris can have a negative impact upon zooplankton function and health. It can be surmised that the zooplankton communities of the Great Lakes can also be negatively impacted by microfibers. A major concern is that since zooplankton is at the bottom of the food chain microplastics (microfibers) can cause a changes in the zooplankton community. This can harm Great Lakes fisheries.

The National Oceanic and Atmospheric Administration defines microplastics as small plastic pieces less than five millimeters long that can be harmful to our aquatic life. They are created by the degradation of larger items, such as discarded single use plastic containers, effluent from wastewater treatment plants and even fallout from the air. Microplastics from wastewater treatment plants comes from discarded plastics, laundering fleece, synthetic fiber clothing, and waste from carpet cleaning. Microplastics in airborne dust can enter the water through wind and runoff from roads and other impervious surfaces.

Ingestion of microplastics by organisms, including mussels, worms, fish, and seabirds, has been widely reported, but the impact of microplastics on zooplankton remains under-researched. It is very difficult to identify microfibers in zooplankton. Microplastics are best identified using 3D bioimaging techniques to document ingestion, egestion, and adherence of microplastics.

Microplastics have been observed adhering to the external carapace and appendages of exposed zooplankton. Ingestion of microplastics can interfere with the digestive system. More research is needed to understand the impact of microplastic debris on zooplankton.

Microplastics and microfibers pollution is well documented in research from universities such as the University of Michigan, Notre Dame, The University of Chicago, University of Wisconsin, Milwaukee and the State University of New York, Fredonia. Researchers from these schools as well as the U.S. Geological Survey have documented the presence of microplastics and microfibers in the Great Lakes since 2013.

Researchers have seen the volume of microplastics and microfibers increase over the years. Microfibers and microplastics have been found in beer brewed with Great Lakes water and drinking water taken from the Great Lakes. It is estimated about 22 million pounds of plastics enter the Great Lakes each year. Unfortunately, there is no legislation that protects our valuable Great Lakes water from plastic pollution.

There are no known solutions for cleaning up microplastic pollution in our lakes and oceans. Plastic does not degrade, it only breaks into smaller and smaller pieces. The only solution for the future is to reduce the amount of single-use plastics and increase the percentage of plastic that is recycled. Currently only 9% of plastic in the United States is recycled. It is cheaper to make virgin plastic from oil than to recycle plastic. Until the economics change, the industry will continue to make virgin plastic from oil and the recycle rate for plastics will remain low.

David Long is the founder of Environmental Sustainability Solutions, LLC (ESS) that provides consulting services for environmental, sustainability.

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