A South Hero landfill has high levels of “forever chemicals”. Nobody knows exactly why
Almost three years after high levels of PFAS were detected at a closed landfill in South Hero, authorities still do not know where the toxic chemicals are coming from at the site.
In December, a landfill monitoring well showed about 3,570 parts per trillion of PFAS – well above the state’s safe standard for drinking water, which is 20 ppt. The chemicals were not detected in the drinking water supplies near the site.
James “Buzz” Surwilo, an environmental analyst at solid waste program, said it was “really surprising” to find this level of PFAS contamination in a rural landfill, as the chemicals are more common at sites with commercial or industrial waste.
“Where that came from, it’s really everyone’s guess,” he said.
Per- and polyfluoroalkyl substances, or “PFAS”, are a family of thousands of chemicals sometimes referred to as “eternal chemicals” because they do not break down naturally in the environment.
PFAS are bound health effects, including cancer, behavioral and developmental problems in infants and children, fertility and pregnancy problems, and immune system problems.
Vermont regulates the level of five specific PFASs in its drinking water: PFOA, PFOS, PFHxS, PFHpA and PFNA. Any combination greater than 20 ppt is considered toxic.
Authorities monitor many closed landfills for PFAS and calculate the sum of each site of these five chemicals, if applicable. The 3,570 ppt reading in South Hero is the highest currently in any closed landfill site in the state, according to data reviewed by VTDigger.
Since 2016, one or more monitoring wells in 20 closed landfills have reported PFAS levels above the state’s safe standard for drinking water, according to data from the Department of Environmental Conservation. Some reports did not reveal the exact levels of certain chemicals, so the total could be higher.
A second monitoring well at the South Hero site reported around 500 ppt of PFAS in December, according to the data.
Surwilo said the state began monitoring closed landfills for PFAS after the chemicals were found in Bennington drinking water wells near two former ChemFab factories in 2016. The discovery sparked outrage. local and a class action lawsuit followed.
In March 2020, PFAS were also found in groundwater near the Vermont Air National Guard base in South Burlington. The contamination was mainly due to the use of now-banned fire-fighting foam, according to a rough draft.
PFAS can be found in a number of consumer products as well as food packaging, non-stick cookware, cosmetics and water resistant clothing.
David Carter, president of South Hero’s Selectboard, said the landfill closed in the 1990s. No local remembers a manufacturing in the area that could have produced toxic waste, he said – there therefore has a chance that the contamination comes from household products.
Engineers last month installed additional monitoring wells to see if contaminated groundwater is migrating past the landfill. The surrounding land has shallow bedrock, Surwilo said, making it difficult to access groundwater for testing.
“We just need more information to understand what’s going on,” he said.
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