PFAS concentrate as they climb Great Lakes food chain
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- University of Notre Dame researchers published a peer-reviewed meta-analysis in the Journal of Environmental Quality, combining 42 years of studies and nearly 2,500 samples of algae, fish, birds, and other Great Lakes organisms to trace how PFAS moves through ecosystems.
- PFOS concentrations dropped dramatically in the lower Great Lakes (Ontario and Erie) over the last two decades after a voluntary industry phaseout in the early 2000s, but showed little to no decline in the upper lakes (Superior, Michigan, Huron), where water retention runs 60–170 years versus 2–7 years for the lower lakes.
- PFAS levels increase as chemicals move up the food chain—algae and plants carry the lowest concentrations because they grow and die quickly, while predators like salmon and eagles accumulate the highest amounts from prey.
- Multiple states including North Carolina, Wisconsin, Montana, and Pennsylvania have issued fish consumption warnings over PFAS levels, and Michigan has tested Great Lakes fish for the chemicals annually since 2012.
- The study covered just six of the more than 15,000 PFAS compounds identified by the National Institutes of Health, and found no national ban exists—only a patchwork of federal regulations and voluntary industry phaseouts of certain chemicals.
- Co-author Gary Lamberti, an aquatic science professor at Notre Dame, said stopping manufacturing allows food webs to eventually cycle out the contamination, calling it "kind of good news for how we can manage these chemicals."
Why it matters: PFAS is detected in nearly all Americans' blood and linked to fertility declines and certain cancers, so the study gives regulators a working model: the lower Great Lakes show measurable PFOS declines roughly two decades after industry pulled back. But upper-lake residents won't see equivalent reductions for generations because those water bodies retain water for 60–170 years—meaning geographic exposure inequities are baked in regardless of how quickly new regulations land.
