By Abbas Nazil
Scientists studying the Great Lakes are intensifying their research on microplastics, a growing environmental threat that could inform both U.S. and global policy, as world leaders continue negotiating a plastic pollution treaty.
Microplastics are now widespread in samples taken from the Great Lakes, raising concerns for both human health and the ecological stability of the basin, which provides freshwater to millions of people in the United States and Canada.
Researchers warn that while microplastics are already linked to reproductive decline, metabolic disorders and behavioral changes in wildlife, their full impact on human health remains unclear.
Chelsea Rochman, a researcher at the University of Toronto and the International Institute for Sustainable Development Experimental Lakes Area in Ontario, has found alarming levels of microplastics in Great Lakes fish.
Testing fish fillets from Lakes Ontario and Superior, she and her team discovered plastic particles in every sample, with some containing hundreds in the gut and dozens in edible portions.
Rochman said fish in the Great Lakes have the highest concentrations of plastic ever measured, suggesting that consumers of regional fish may face elevated risks.
Despite this, Rochman emphasized that fish are not the primary exposure pathway, since microplastics are present in air, water and food.
Her research is helping shape recommendations for both the U.S. and Canadian governments, including frameworks for monitoring, risk assessment and basin-wide pollution prevention strategies.
Other researchers are working to develop technologies to remove microplastics and related contaminants from the water.
Junhong Chen of the University of Chicago is co-leading the Great Lakes ReNEW Water Innovation Engine, a 10-year project funded by a $160 million National Science Foundation grant.
The program aims to recycle wastewater, recover useful minerals and create sustainable water systems by filtering out pollutants such as PFAS, bacteria and microplastics.
Global attention on plastics is also growing.
In Geneva this month, 184 countries gathered to negotiate a treaty on plastic pollution, though talks ended without agreement.
Experts like Oregon State University ecotoxicologist Susanne Brander argue that upstream measures are essential, including banning toxic polymers, mandating recycling and setting reduction targets for plastic production.
Recycling and cleanup alone, she said, will not solve the crisis.
Rochman and colleagues have pushed for microplastics to be recognized under the Great Lakes Water Quality Agreement as a chemical of mutual concern, which would require regular monitoring and policy responses every three years.
Their 2024 report also called for basin-wide tracking programs and emission prevention measures.
Future research will focus on human health impacts, particularly as microplastics break down into even smaller nanoplastics that are harder to detect.
Scientists stress the urgent need for standardized methods to measure these particles so that governments can act with greater certainty.
Some U.S. states are already stepping ahead.
California has implemented microplastic testing standards in drinking water, while Michigan lawmakers have introduced bills for statewide monitoring.
Experts believe state-level leadership could drive regional action in the absence of international agreements.
With the Great Lakes providing nearly 90 percent of U.S. freshwater, scientists caution that ignoring the issue risks both ecological damage and potential health impacts.
They hope that their research, combined with mounting global pressure, will push policymakers to act swiftly on regulating plastic pollution.
