Lewiston-Auburn Water Pollution Control Authority on Lincoln Street in Lewiston. Russ Dillingham/Sun Journal

LEWISTON — The Lewiston-Auburn Water Pollution Control Authority has put a hold on sending sewage sludge to local farms for fertilizer because it tested high for a chemical linked to cancer and other ailments.

A majority of treatment facilities tested so far have had levels of at least one type of per- and polyfluoroalkyl (PFAS) substance high enough to merit additional state testing, according to state officials.

PFAS, a family of potentially thousands of synthetic chemicals, are known as “forever” substances because they are extremely persistent in the environment and in our bodies.

The Lewiston facility is among dozens that are grappling with where to send the contaminated sludge.

Authority Superintendent Mac Richardson said last week that he is “looking at all possibilities” moving forward after the initial tests. For now, however, the authority is sending all sludge to the Juniper Ridge landfill in Old Town, which is managed by Casella Waste Systems.

Because additional testing is required to continue farm applications, many treatment facilities, like Lewiston, are opting to send all sludge to landfills.

Increased scrutiny over the chemicals followed revelations that a dairy farm in Arundel had elevated levels of the contaminant in its soil, water and milk. In March, the Maine Department of Environmental Protection announced that it would begin testing all sludge material licensed for land application in the state for three types of PFAS substances.

Earlier that month, Gov. Janet Mills established a task force to review the prevalence of PFAS in Maine and to create a plan to address it.

PFAS were used for decades in nonstick cookware and firefighting foam, among other things, and have since been linked to cancer, thyroid disruption and reproductive and immunological changes in lab animals.

Treated sewage sludge, also known as “biosolids,” has been commonly used on farms as fertilizer or distributed as compost. Treatment plants are required to analyze sludge for a number of contaminants but there had not been a requirement to test for PFAS, until now.

The initial test in Lewiston showed that its material exceeded the 5.2 parts per billion screening standard for PFOS (one type of PFAS) at 13.8 parts per billion. The other two types of PFAS tested below the limit of detection.

David Burns, director of the DEP’s Bureau of Remediation and Waste Management, said last week that the results in Lewiston are in line with what he has seen statewide. Most sludge in Maine is testing high for the PFOS type, he said, while about half are exceeding levels for PFOA. The third type tested, PFBS, has not been a problem, he said. The state has not yet released the full results.

Burns, as well as local officials, stressed that the screening levels in state statute are not official standards or safety levels. He said a standard would mean it cannot be exceeded, but that a screening level is set to require additional testing.

As the DEP monitors the results, it is working on additional testing with treatment plants that are licensed for land application.

If a treatment plant that tests above the screening standard opts to pursue further land applications, it must first test the soil at sites where the sludge has been applied in the past. If the soil from the farm is below the screening level, the land application can continue.

However, the state is limiting its approval of land applications in these circumstances to one year, Burns said, in order “to digest all of the data once it’s in and determine what the appropriate course of action is.”

Burns said that faced with the additional testing, many treatment facilities are deciding to forgo the soil tests on sites where sludge has been applied.

“A lot of facilities that would be subject to that same requirement have opted at this point in time not to do the site-specific soil testing and instead are finding alternative outlets for their biosolids,” Burns said.

The board of directors at the Lewiston-Auburn Water Pollution Control Authority recently decided the same, voting to send all of its sludge to a landfill, for now. That’s despite having clearance to continue applications on a limited number of fields.

Richardson said that many facilities are struggling with what to do with the material, especially if it has exceeded any of the screening levels. He said Lewiston may do testing at specific sites, and depending on the results, may continue with limited applications.

“We’re trying to work with our farmers and make sure they’re comfortable,” he said. “This is quite a concern for farmers because of some of the negative publicity that’s been out there. So there’s just a lot of pieces we have to figure out before we resume.”

The pollution control authority typically provides sludge to between six and 10 farms each season. In total, it has provided material to more than 20 farms.

Late last year, the authority suspended operations at its compost facility.

The amount of biosolids the plant generates has been cut in half since the facility employed anaerobic digestion, a process in which micro-organisms break down material, resulting in biogas, which can be combusted to generate electricity and heat. Richardson said farm requests for material from the Lewiston plant doubled at that time because the process also reduces odor.

Richardson said that much of the information on PFAS is “still developing,” and that the screening standards are based on “preliminary figures.”

“You could argue it either way — that they’re either too stringent or not stringent enough,” he said.

Michael Belliveau, the executive director of the Environmental Health Strategy Center in Portland, said in March that the Arundel case “is likely the tip of the toxic iceberg.”

Richardson has said that none of the farms receiving material from the Lewiston facility have experienced issues similar to Stone Ridge Farm in Arundel.

Burns said 72 facilities are required to submit samples for testing and the state has received samples from about 80% so far.

In Androscoggin, Franklin and Oxford counties, 10 facilities are required to take part in the testing. So far, only compost facilities in New Sharon and Kingfield and the Bethel treatment facility have not yet submitted samples for testing.

The tests have also been conducted for compost produced by treatment facilities, and for a small number of paper mills, including two locations in Jay. For these tests, Burns said, the compost is most often exceeding the standard for PFOA, a different variation of PFAS than what is testing high in sludge.