The most comprehensive study on per-and polyfluoroalkyl substances (PFAS) through the entire food web found some decreases in the Great Lakes, but not in all areas.
PFAS are a group of man-made chemicals, otherwise known as forever chemicals, that were used for decades to make products heat, water, stain and grease resistant. Non-stick products such as Teflon are one example. Many PFAS have been banned, but the substances are slow to break down.
Forever chemicals bio-accumulate through the food web, with higher concentrations at the top of the chain in animals like eagles, top fish predators and humans. Although studies have been completed for decades tracking PFAS at the top of the food chain, a recent study by the University of Notre Dame is the most comprehensive to look at the entire food aquatic food web.
The study found PFOS (perfluorooctane sulfonate), one of the PFAS, decreased in the lower Great Lakes, but not in Huron, Michigan, or Superior as the larger, deeper lakes see a slower turnover of water. This contrast is lake turnover varies from two to seven years for the lower lakes compared to 60 to 170 years for the upper lakes. PFOS was used in firefighting foams and stain-resistant coatings for fabrics. A voluntary phase-out of PFOS started more than two decades ago.
The Notre Dame study looked at 42 years of data collected on PFAS and more than 2,500 samples. The study also found PFAS transfer from one organism to another through the food web. It found the lowest concentrations at the bottom of the food web in organisms like algae, and the highest concentrations in top predators like salmon and eagles.
OFAH Fisheries Biologist Adam Weir penned a letter in conjunction with Pollution Probe to the federal government, endorsing a risk assessment on PFAS and the proposed ban of the substances in firefighting foams. The letter points out the health risks to anglers from consuming fish contaminated with PFAS.
