A Call for Sludge Regulation

A Maine farm group plans to sue to prompt federal action, and new data confirms the widespread presence of PFAS in rain

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Eight years ago, Maine uncovered the edge of a vast agricultural problem when PFAS (per- and polyfluoroalkyl substances) surfaced on a third-generation dairy farm. The toxic fluorinated compounds in the farm’s water, soil, pasture grasses and milk traced back to wastewater sludge spread on fields more than a decade earlier.

The U.S. Environmental Protection Agency (EPA) and most state agricultural departments still promote land-spreading as a “beneficial use” of sludge, despite knowing that the “forever chemicals” it contains pose serious health risks, disrupting hormonal, immune and reproductive systems and increasing the risk of various cancers.

Among more than 700 chemical compounds the EPA has identified in the residual wastewater sludge that industry terms “biosolids,” PFAS are nearly universal. “What’s different about Maine is that we’re actually looking for it,” says Sarah Alexander, executive director of the Maine Organic Farmers and Gardeners Association (MOFGA). To date, state agencies in Maine have found more than 70 PFAS-contaminated farms, a handful of which have had to cease all food production.

In 2022, Maine became the first state to ban land application of sludge and the sale of compost containing sludge. No such protections exist for the larger U.S. food supply, Alexander notes. Each year, more than half of the nation’s sewage sludge is land-applied, the EPA reports, with 31 percent spread on agricultural lands and the balance going to settings like home gardens, landscaping, athletic fields, golf courses and parks.

To force faster adoption of federal regulations governing PFAS in sludge, MOFGA announced last week its intent to join a lawsuit against the EPA with Public Employees for Environmental Responsibility (PEER), an environmental watchdog group that notified the EPA in February of its intent to sue. That action followed sludge contamination incidents affecting farmers in Texas, South Carolina, Michigan and other states.

“A patchwork approach across the states is not going to work,” Alexander says; what’s needed is a coordinated and timely response from the EPA, the U.S. Department of Agriculture and the U.S. Food and Drug Administration.

The EPA plans to complete a risk assessment this year of two PFAS compounds commonly found in sludge, but Alexander says that’s “too little and way too late.”

The Clean Water Act mandates that the EPA review sewage sludge regulations every two years and address pollutants that could be harmful. According to MOFGA, the EPA has promulgated only nine regulations governing land application of sewage sludge. At least 12 of the PFAS found to date in sludge have clear scientific evidence demonstrating public harm, MOFGA asserts.

Evidence of risks from sludge has been accumulating for decades. A 1997 report by the Cornell University Waste Management Institute urged the EPA to adopt stricter sludge regulations and “take a closer look at the contents of sewage sludges and the conditions under which they are applied.”

“Sewage sludge is widely suspected as a major sink” of PFAS, researchers wrote in 2005, since the compounds adsorb to solids during wastewater treatment. Christopher Higgins, an environmental engineering professor at the Colorado School of Mines, coauthored that research and worked with colleagues on a 2011 published study that found PFAS levels in soil rose proportionate to the volume of municipal sludge applied. By then, the EPA had confronted record-high levels of PFAS on Alabama pastures treated with sludge that incorporated waste from a fluorochemical manufacturer.

Higgins recalls trying to convince the EPA and wastewater industry associations that a multi-million-dollar research program was needed to assess the risks that PFAS in sludge might pose for groundwater, soil health and the food supply, but he says “there was no real interest in doing the research and asking the hard questions.” When he presented study findings to waste industry officials, he recalls that “they wanted to stick their heads in the sand and say there is no problem.”

When EPA established drinking water standards this spring for some prevalent PFAS compounds, the agency acknowledged that “there is no level of exposure to these contaminants without risk of health impacts, including certain cancers.” The EPA describes PFAS as “an urgent public health and environmental issue,” but in MOFGA’s estimation, regulation does not yet match rhetoric. “We know the risks are there,” Alexander says. “We want them to take action.”

Widespread use and disposal of PFAS underlies the ongoing contamination of sludge, the EPA wrote in a statement last year. There are no viable means presently to remove PFAS from sludge at scale or to remediate the farm soils that sludge contaminates.

The plight of farmers whose lives were upended by toxic sludge convinced Maine to lead the nation in passing a phased-in ban on PFAS in most products. The only viable means to manage chemicals this persistent and pernicious, legislators realized, is to largely eliminate their use.

“No one can undo the historic contamination of our land,” testified one Maine farmer who lost his home and business due to sludge. “But we know enough now to turn off the tap.”

Research: No Longer ‘Right as Rain’

Detectable levels of PFAS appeared in most of the rainwater samples gathered between 2020 and 2022 through a collaborative testing project undertaken by the U.S. Environmental Protection Agency (EPA) and the National Atmospheric Deposition Program (NADP). EPA released the data in April to research partners, working toward two peer-reviewed manuscripts: one that evaluates the performance of the NADP’s PFAS-measuring techniques, and a second that discusses “the fluxes and measured concentrations of PFAS compounds,” according to an EPA spokesperson.

The testing for PFAS in weekly or biweekly rainwater samples began at four established “National Trends Network” sites in central North Carolina, New Jersey, upstate New York and coastal Maine, and grew to include three additional sites in the Midwest and West.

A diversity of PFAS compounds (among 30 that were assessed) occurred within and among the samples gathered, including “legacy” long-chain compounds, newer “GenX” formulas and precursor compounds (which can, over time, transform into more stable and enduring PFAS). Many samples had fewer than 5 PFAS analytes, some had between 5 and 10 analytes and a few had more than 10 analytes.

Levels and mixes of the chemicals vary widely because “rain is cleaning the atmosphere,” explains Rainer Lohman, who directs a PFAS research center at the University of Rhode Island. What collects in the rain depends in part on what PFAS were released from land-based sources like manufacturing facilities, landfills and wastewater treatment plants, or from the ocean itself (where PFAS appear to return to the land on ocean breezes).

A newly published study of PFAS in air and rain at sites around the Great Lakes found PFAS levels were as high in rainfall at rural sites as urban ones. (Airborne PFAS were notably higher in urban samples.) At remote lakes, researchers found, rain can be a significant pathway for PFAS to enter ecosystems.

The recent studies echo findings from a 2022 scientific review that compared levels of four PFAS compounds in several environmental media, including rainfall, around the globe. In numerous locations, rainwater greatly exceeded the EPA’s lifetime drinking water health advisory levels for PFAS. Researchers noted that atmospheric transport of these highly persistent chemicals is hard to reverse because they can cycle indefinitely.

News of Note

• An environmental health study published in late April reveals that New Jersey residents in “overburdened communities” face disproportionate PFAS exposure, with significantly more of the Black, Asian, and Hispanic populations drinking PFAS-contaminated water than the non-Hispanic white population.

• Sharon Lerner at Pro Publica, who has written extensively about the corporate cover-up of PFAS threats, has a fascinating and discouraging new piece based on extensive interviews with former 3M scientists.

• Participants at the recent Intergovernmental Negotiating Committee on Plastic Pollution in Ottawa, Canada, made little headway and encountered strong industry influence on treaty negotiations, Lisa Song reports in Pro Publica.

• A new study of PFAS in seafood found that shrimp and lobster ranked highest (and while there are federal guidelines for safe seafood consumption with some contaminants, none have been set for PFAS). Nor are there federal guidelines for safe PFAS levels in milk, as a recent Consumer Reports investigation noted. It found elevated PFAS in six of 50 milk samples, including some organic and grass-fed varieties (PFAS accumulate more in grasses/hay than grains).

• If the report on microplastics’ potential health effects in the March issue of ContamiNation didn’t get your attention, two recent studies on microplastics in testes may. Researchers at the University of New Mexico looking at testicular tissue from humans and dogs found significant concentrations of 12 types of microplastics, raising concerns about reproductive health impacts. Meanwhile, scientists in China found microplastics in all the human testes samples they tested and in the majority of semen samples.

• Scientists recently learned that friction occurring during the assembly and disassembly of toy building bricks generates nanoplastics and microplastics (primarily acrylonitrile butadiene styrene or polycarbonate, a potential inhalation concern). Researchers suggest—at a minimum—washing hands after play (but it’s hard not to think about all the other places plastic undergoes friction—like in food processors and salad spinners.)

Good Riddance

With weeds outpacing vegetables in our garden, my thoughts turn to mulch options. Many years ago, in a move of desperation, I tried black plastic as a means to control quackgrass. Bits of that enduring material still surface periodically and I try not to think about the invisible microplastics likely still present. Agriculture at every scale is heavily reliant on plastics, as pieces in Civil Eats and The Atlantic have recently noted, but as more studies emerge about plastic impacts at global and cellular scales, farmers and gardeners are looking for alternatives. Fortunately, there are websites and books out there to help.

Thanks for reading!