The long-standing practice of spreading treated sewage sludge and septage on farm fields has contaminated groundwater in some areas with PFAS, recent sampling shows.
The discovery has prompted a state agriculture official to say that a prohibition on harvesting feed and crops from those fields may be needed, And it has led a coalition of environmental groups to call on the state to test for PFAS levels in biosolids before they are spread on fields.
After seven out of 34 land application sites in Vermont were found to have PFAS levels above state groundwater standards, the state Department of Environmental Conservation is considering measures to prevent future contamination.
Vermont wastewater treatment plant operators and septic companies must dispose of the residual end products somewhere, and their options are limited. With tight capacity at southern New England incinerators, they can send it to a landfill or to a processing plant in New York, or spread it on fields as fertilizer.
Sludge and septage to be spread on fields must be treated to EPA standards to reduce pathogens and limit heavy metals, and are called “biosolids.” Critics have argued those standards do not address the thousands of chemicals that now show up in human waste, like pharmaceuticals and PFAS.
Per- and polyfluoroalkyl substances, or “PFAS,” gained notoriety in Vermont after the state discovered in 2016 that a particularly toxic form of the chemical had contaminated hundreds of drinking water wells around two former ChemFab factories in Bennington. That discovery prompted the DEC to start widespread sampling to better understand other potential sources of PFAS drinking water contamination.
Last fall the state began requiring wastewater plants and septic companies to test soil and groundwater for PFAS levels at fields where biosolids are spread.
“We found a couple fields were fine, and we found a couple that were pretty high,” Chuck Schwer, director of the waste management and prevention division for DEC, said of the initial sampling. “So we felt it was prudent to then require all the permittees to sample their fields.”
The “really good news” from the expanded testing is that no drinking water wells within a quarter mile radius of the fields have elevated PFAS levels, Schwer said.
But the municipalities of Bradford, Essex Junction, St. Johnsbury, Woodstock, and private company P&P Septic Services, all had had one or groundwater samples at fields where they spread biosolids come back with elevated PFAS levels. (Vermont’s groundwater enforcement standard for PFAS is a combined 20 parts per trillion for five of the compounds.) Those entities will now have to pay for further sampling to determine the extent of the contamination and if cleanup work is needed, said Schwer.
Schwer hopes that Vermont’s lawsuit against DuPont, 3M and other PFAS manufacturers will result in some funding that could help municipalities pay for this kind of work.
“But that’s a long way down the road, and there’s no guarantee we’ll be successful,” he added.
The soil samples taken at the fields where biosolids are spread had low to moderate PFAS levels, said Schwer. The state Agency of Agriculture, Food and Markets has been working with farmers who have contaminated soils to determine whether they need to only harvest part of their crop, Cary Giguere, public health and agriculture resource management director for the state Agency of Agriculture, Food and Markets, told lawmakers on Tuesday.
One farm that had higher than background levels of PFOS chose to only harvest corn ears last fall as that chemical does not get taken up in that part of the crop, he said in an email.
“Until we can get this contamination piece under control, I do believe a prohibition on land that’s used for food or feed would be appropriate,” Giguere told members of the House Agriculture and Forestry Committee on Tuesday, adding that this would leave “the Agency of Natural Resources with a problem of where does it go, and who deals with that problem. It might make it expensive for municipalities, which is why we’ve ended up where we are.”
A South Burlington farmer dumped milk after discovering in 2016 that his cows had been drinking from a well contaminated with fire fighting foam laden-runoff from the Vermont Air National Guard base. The milk did not have detectable levels of PFAS after a treatment system was installed at the well. But the agriculture agency is looking for funding for additional testing at other farms, Giguere said, adding that he did not expect to detect elevated PFAS levels in milk based on similar studies in other states.
Eamon Twohig, head of the DEC’s residuals management program, said “there’s no question” that losing biosolid application as a disposal option would cost municipalities, and consequently ratepayers, as well as septic companies more money. He also has broader concerns about what some municipalities would do with sludge if it couldn’t be land applied.
“It makes me nervous to think that a small Vermont wastewater treatment plant would generate sludge, put it in a roll off container, try to find a place to take that roll container” and be told no one will accept it, he said.
Jackie Folsom, legislative director for the Vermont Farm Bureau, said that she has not heard from any members on this issue, noting that biosolids are spread on a small portion of agricultural fields in the state.
“But I think that farmers want to play by the rules and they want to do things that make them good stewards of the environment. And they’re caught in the middle — there’s no standards for this in land application,” she said in an interview Wednesday, adding “I would suspect that probably fewer and fewer of them will be allowing this on their land, and that’s probably a good thing.”
A coalition of five environmental groups, including the Conservation Law Foundation, has called for just such a standard. In comments filed Tuesday on DEC’s proposed solid waste rules, the groups ask that the state require applicants test for PFAS levels in biosolids before spreading, as they have to do for certain heavy metals, and routinely test biosolids spreading sites.
Elena Mihaly, senior attorney at CLF, said they see this as part of a broader request for ANR to develop a “comprehensive” approach to limiting Vermonters exposure to PFAS.
In the case of biosolids, “we have these wastes we’re trying to get rid of, we’re spreading them on fields we know they contain PFAS,” she said. “It’s about time that we develop a standard screening level that tells us…when it is and when it isn’t safe to be land applying this stuff.”
She added that environmental advocates have also been pushing for S.295, a bill that would limit PFAS levels in items like carpeting and food packaging, where it is commonly found.
“The source of PFAS is the consumer products that get landfilled in the first place or go down our drains at home,” Mihaly said. “So the more we can limit and put bans on the sale and manufacture of those consumer products, the better.”
