PFAS found in the Great Lakes, detected in fish and water supplies

Researchers report PFAS — persistent synthetic chemicals — have been detected in Great Lakes water, sediments, shoreline foams and fish; sources identified include industrial sites, firefighting foam, wastewater and atmospheric deposition.

Researchers and water managers are documenting the presence of PFAS, a large group of long-lasting synthetic chemicals, in the Great Lakes system. The lakes supply drinking water to more than 30 million people and support important commercial and recreational fisheries. PFAS have been used for decades in many products and do not break down easily. Recent monitoring finds these chemicals in rivers, groundwater, precipitation, sediments, shoreline foams and in fish across the region. Key points: - PFAS have been detected in Great Lakes tributaries, groundwater plumes, lake sediments, shoreline foams and in fish, with levels varying by location. - Identified sources include industrial sites, military use of firefighting foam, wastewater treatment plants, some pesticides and atmospheric deposition from distant sources. - The article cites examples of elevated measurements, including tributary concentrations above 1,700 parts-per-trillion near repeated foam use and more than 260 parts-per-trillion in Green Bay, and notes that foams can concentrate PFAS far above water levels. - PFAS are persistent and can move between water, sediment and biota; some compounds bioaccumulate in fish, which has led to consumption advisories in some areas. - Researchers and programs such as Sea Grant and the National Institutes of Water Resources are mapping contaminated groundwater and rivers to inform policymakers and resource managers. Summary: PFAS are now detected across multiple parts of the Great Lakes system and are linked to a range of upstream and local sources. Concentrations and exposure pathways vary, and sediments and natural foams can hold or release these chemicals over time. Ongoing research and mapping efforts are being used to identify sources and inform management; preventing additional inputs is emphasized because water residence times in the lakes can extend from years to centuries.