Declining PFAS Levels in Great Lakes Fish Reflect Positive Environmental Changes
A recent study in the Journal of Great Lakes Research uncovers a positive environmental trend: the decline of PFAS levels in fish from the Great Lakes. This improvement is linked to the reduction of certain chemicals by manufacturers over the past few decades.
Researchers from the Environmental Protection Agency’s Duluth lab have analyzed PFAS content in nearly 1,000 fish samples, including lake trout and walleye, from the five Great Lakes, spanning from 1975 to 2020. Their findings indicate that PFAS concentrations peaked between 2007 and 2017, followed by a steady decline, according to Sarah Balgooyen, the study’s lead author.
“We do see the ecosystem responding to these changes in industrial practices, which is a great thing,” Balgooyen stated. “We know that industry is in a very powerful position at this point because what they do changes what’s happening in our environment.”
The decline in PFAS levels is primarily attributed to the early 2000s agreement by manufacturers to phase out two common PFAS chemicals, notably PFOS. This substance, known for accumulating in fish and humans, was found in all samples tested.
Balgooyen, now affiliated with the Colorado School of Mines and a former research chemist at the EPA, noted that under President Donald Trump, the EPA reorganized and eliminated the office responsible for researching environmental risks, including those from PFAS.
These synthetic chemicals, known as per-and polyfluoroalkyl substances, are linked to health risks such as kidney and testicular cancers. They are termed “forever chemicals” due to their persistence in the environment.
Peak PFAS levels were recorded at around 450 parts per billion (ppb) in Lake Erie, subsequently decreasing to about 50 ppb by 2020. Lake Michigan saw a peak at approximately 150 ppb, which fell to about 80 ppb. Lake Superior, with its fewer industrial activities, had lower PFAS levels, peaking at 60 ppb and decreasing to 25 ppb by 2020.
Eric Haataja, a fishing charter captain in Milwaukee, welcomed the findings as beneficial for those who enjoy eating fish, stating, “It’s healthier. It’s better for you if there’s less of the toxins.” He also advocated for federal support to enable industries and wastewater treatment facilities to filter out such chemicals before they enter the lakes.
Lakes Erie and Ontario had consistently higher PFAS levels due to significant industrial activity and population density, leading to wastewater discharge into these lakes. PFAS are employed in various industries, including paper mills and metal plating, and are found in household products like non-stick cookware and stain-resistant carpets.
According to Gary Ankley, a former EPA research toxicologist and co-author of the study, there is optimism regarding the decrease in PFAS levels. However, he cautions that the levels might not yet be sufficiently low. He pointed out that guidelines for unsafe levels in fish consumption have evolved as new scientific insights emerge, prompting lower PFAS limits in drinking water.
The Wisconsin Department of Natural Resources (DNR) advised in 2020 avoiding fish with PFOS levels above 200 ppb. Recently updated guidelines suggest fish with levels over 40 ppb are unsafe to consume, says Sean Strom, the DNR’s fish and wildlife toxicologist.
Currently, anglers are advised to limit consumption of smelt to once a month in Lake Superior and once a week for smelt and yellow perch in Lake Michigan. The DNR plans to revise these guidelines later this spring.
Balgooyen emphasizes the importance of adhering to these advisories, given the ongoing uncertainties about PFAS’s health impacts. Ankley highlights the significance of a robust scientific and regulatory framework to continue reducing environmental contamination.
