The massive spill of firefighting foam in August at the former Brunswick Naval Air Station once again brought renewed attention to a group of chemicals called PFAS, per- or polyfluoroalkyl substances, also known as “forever” chemicals. The spill released 1,450 gallons of aqueous film-forming foam combined with 50,000 gallons of water into the surrounding area in Brunswick, entering the watershed and eventually Harpswell Cove.
Dr. Chris Aeppli in the Bigelow PFAS lab. BLOS photo.
PFAS had been in the news before. In 2021 the Maine Department of Environmental Protection (DEP) revealed that 70 Maine farms had been contaminated with PFAS through municipal sewage waste sludge applied as fertilizer to the properties. The chemicals moved into the soil, water, and farm crops. Maine residents grew alarmed that PFAS also could be in their well water or municipal water systems.
PFAS are not benevolent chemicals. They comprise more than 10,000 synthetic chemicals that have been widely used in consumer products since the 1950s. They pose serious and long-term health consequences, including increased risk for kidney or testicular cancer, liver damage, high cholesterol, pregnancy complications, decreased fertility, lower birth weight in infants, among other risks. According to the Centers for Disease Control (CDC), the health effects of exposures to mixtures of different PFAS are still unknown.
“PFAS are designed to withstand harsh environmental conditions,” explained Dr. Christoph Aeppli, senior research scientist at Bigelow Laboratory for Ocean Sciences and head of its new PFAS analytical services lab. The lab is certified by Maine, and can test for PFAS presence in water, sediment, soil, and plant and animal tissue for state agencies, commercial customers, and the general public. “Like Teflon, they are hard to break down.”
PFAS can build up, or bioaccumulate, in animals. The higher up the food chain the animal, the more likely the bioaccumulation.
PFAS are drawn to proteins, fluids, and organs, unlike DDT, which builds up in fatty tissues. As they move through river systems and ultimately into the ocean, they are taken up by marine organisms, both on the seafloor and throughout the water column. Certain types of older PFAS concentrate in animals through the prey they eat, while newer PFAS can move directly from the water column into fish through their gills.
“PFAS are a big group [of chemicals]. Each has a different toxicity,” Aeppli said. “Detection does not necessarily mean toxicity. But the more you have the more toxic it generally is.”
The Surface Water Ambient Toxics Monitoring Program (SWAT) in the DEP monitors for 40 different PFAS in fish and shellfish. In 2021 it analyzed lobsters taken from 18 sites in the seven lobster management zones.
Half of the sites had no detected PFAS in lobster meat. The other half, which were collected from the southwestern zones, had very low concentrations. SWAT collected and analyzed softshell clams from six sites in 2022. The results indicated low concentrations of PFAS compounds in clam tissue, too low to warrant a public health advisory.
The federal Food and Drug Administration (FDA) issued an advisory update on PFAS and seafood in April this year.
“Our testing, which included a targeted survey to sample seafood, has so far indicated that seafood may be at higher risk for environmental PFAS contamination compared to other types of foods. While the data on PFAS in seafood is still very limited, filter feeders, such as clams, but also other bivalve mollusks, including oysters, mussels, and scallops, may have the potential to bioaccumulate more environmental contaminants than other seafood types,” the advisory stated.
But are PFAS found in Gulf of Maine lobster and other marine species at levels high enough to warrant concern? A recent Dartmouth College study of Gulf of Maine seafood purchased in New Hampshire, published in April in the journal Exposure & Health, suggested that “high seafood consumers may be exposed to PFAS concentrations that potentially pose a health risk.”
The Dartmouth study found instances of PFAS in 26 seafood species, including cod, haddock, lobster, salmon, scallop, shrimp, and tuna. Shrimp and lobster showed the highest levels of PFAS, with average concentrations reaching up to 1.74 and 3.30 ng/g (nanograms per gram of tissue).
Aeppli said anyone concerned about PFAS in seafood should put the Dartmouth study into perspective.
“The sample size [of seafood in the study] is relatively small. The authors analyzed three samples of each seafood item. This is a good start but not sufficient for drawing very general conclusions,” he explained in an email. “The PFAS concentrations were relatively low. For example, PFOS, the most toxic PFAS, was below detection for salmon, scallops, and tuna and below 1 ng/g for haddock and lobster. Even for shrimp, the species with the relatively highest concentration, PFAS only reached up to 2.6 ng/g. For comparison, the Maine CDC action level in fish is 3.5 ng/g for PFOS.”
“DEP was the first to look systematically at PFAS in marine species, but the focus has mostly been on shellfish. There’s been no large survey of commercial seafood species, and that is needed,” he said.
For more information, visit Maine Department of Environmental Protection.
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