Six-month-old brook trout for stocking area lakes and ponds are shown in this 2019 file photo. Credit: Linda Coan O'Kresik / BDN

Maine could issue more “do not eat” advisories for freshwater fish due to contamination from so-called forever chemicals, as the state continues to come to grips with the extent of contamination from the class of chemicals that manufacturers have used in everyday products for decades.

State health and environmental officials are considering a lower safety threshold for PFAS contamination in fish as they act on new information from a federal agency about just how toxic the chemicals are to humans.

The action follows years of testing of fish that have shown a number of species in state waterways with elevated contamination levels. That testing has also revealed a handful of hotspots for contamination in the state, such as Fairfield — where state officials last fall told hunters not to eat deer — and the former Loring Air Force Base in Aroostook County.

Currently, the state’s safety threshold for PFAS in fish — the level of contamination at which the state warns people against consumption — is 34 parts PFAS per billion. The state is weighing whether to lower that threshold to three or four parts per billion, according to Tom Danielson, an aquatic biologist with the Maine Department of Environmental Protection and Robert Long, a spokesperson for the Maine Center for Disease Control and Prevention.

That change would follow a similar move by Massachusetts, and would be based on information from the federal Agency for Toxic Substances and Disease Registry showing that contamination levels previously thought to be safe are actually too high for humans. PFAS have been connected with a number of health effects, including elevated risk of kidney and testicular cancer and small decreases in infant birth weight.

There have already been limits for years on the amount of freshwater fish considered safe to eat due to mercury pollution. A lower threshold for PFAS — and specifically, one kind of forever chemical called PFOS — means that even more fish across Maine would be considered dangerous to eat, and that people in some places should be concerned, Danielson said.

“Some of the highest levels of PFOS we’ve found in fish are in the hundreds of parts per billion,” Danielson said. “We’re trying to develop some fish consumption advisories, warning folks in some cases to just not eat fish from certain water bodies.”

Danielson and his colleagues have tested a variety of fish in waters across Maine over the last seven years. In 2019, for example, smallmouth bass from parts of the Androscoggin River had some of the highest levels of contamination in fish tested that year. The fish had contamination levels as low as 2 parts per billion and as high as 14. While all of those fish are considered safe to eat under Maine’s current standard, half of the samples from that year would be considered unsafe to eat under the state’s likely new safety threshold.

While Danielson and his colleagues have identified a number of hotspots for PFAS contamination, working out the source of contamination is more complicated.

It’s widely known that PFAS have been used in paper manufacturing over the years, and that runoff from state-licensed landfills has tested high for PFAS contamination. In addition, wastewater treatment plants — because they receive runoff from landfills, industrial waste and from sewage from homes where PFAS end up in human waste — release millions of gallons of wastewater into rivers each day that could contain elevated PFAS levels.

Waters by the former Loring Air Force Base in Limestone, where lots of PFAS-containing firefighting foam was used over the years, have fish that testing has shown to have high PFAS levels, Danielson said.

In one instance, fish tested near a closed landfill showed concentrations of PFOS in the thousands of parts per billion, he said.

And in Fairfield, high levels of contamination in fish follow the discovery of high levels of PFAS in more than half of the deer tested there last fall. The Department of Environmental Protection had previously discovered high levels of PFAS in soils in that area.

Toxins in fish aren’t new. But PFAS behave differently in fish from mercury, which is more familiar to scientists, according to Diane Kopec, a faculty fellow at the George J. Mitchell Center for Sustainability Solutions at the University of Maine.

While mercury tends to collect in fish muscle, PFAS contamination appears to be more widespread throughout the fish, which could be more harmful to animals that eat the fish.

“When you’re looking at a food web, animals don’t take out the filet and leave the internal organs behind,” Kopec said. “An animal that eats the fish eats the whole fish.”

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Sawyer Loftus

Sawyer Loftus is an investigative reporter at the Bangor Daily News. A graduate of the University of Vermont, Sawyer grew up in Vermont where he worked for Vermont Public Radio, The Burlington Free Press...