The horror story started for Katia Holmes on a chilly January day when she learned the organic milk produced by her beloved herd of Jersey cows was toxic to humans.
Testing found the milk contained dangerously high levels of per- and poly-fluoroalkyls (PFAS) — a group of water- and grease-repellent chemicals used in everything from takeout containers to raincoats. Nearly impossible to destroy, they accumulate in human bodies and can trigger a range of health problems. Finding unwanted chemicals in their milk forced Holmes and her husband Brendan to temporarily shut down their Maine dairy farm.
"It was a hard moment for us because we've spent 18 years building this farm," she recalled. "We went from a thriving, diverse farm business to no income overnight, and for a month didn't sell anything."
They traced the contamination to hay grown on a nearby field that had been fertilized decades earlier with biosolids, or sewage sludge from municipal wastewater treatment facilities. Like most sewage treatment plants in both Canada and the U.S., these treatment facilities weren't equipped to filter out the PFAS, which were present in higher quantities than normal because of waste from local paper mills, and allowed them to concentrate in the residual sludge.
When the sludge ended up on local fields, it made its way into hay and, eventually, Holmes' herd of Jersey cows. The problem is, fertilizing fields with biosolids isn't limited to Maine. Canadian farmers also use the sludge and applied over 500,000 tonnes of it to their fields in 2020, according to federal data.
Yet almost none of Canada's farm-bound biosolids are being tested for PFAS.
Canada's sewage waste is regularly monitored for potentially harmful chemicals like chlorine, heavy metals or toxic bacteria and viruses. It isn't checked for PFAS and a host of other "emerging" toxins like microplastics, according to the National Pollutant Release Inventory, a federal database that tracks pollution.
Four types of PFAS have been banned in Canada since 2016, but dozens of types of PFAS similar to the banned toxins are still widely used. These legal chemicals are often just as harmful and indestructible, accumulating in the environment and human bodies over time.
While Environment and Climate Change Canada (ECCC) monitors for these PFAS in wastewater "on a rotating basis," the ministry said it "currently does not have any measures in place" to keep track of the chemicals in groundwater and/or agricultural soils.
Neither do provincial, territorial or municipal governments. Take Ontario, the Canadian province that last year applied the most sewage sludge and where the agricultural impact of PFAS in sewage sludge has been most widely studied. In 2008, the province partnered with the federal government to examine whether biosolids applied to fields would leech PFAS into the environment or into a crop of wheat. The province hasn't conducted similar research since, though it "continues to track science" on the issue, a spokesperson explained.
While the 2008 study determined the plants didn't absorb the toxins, a 2021 fact sheet published by the Water Association of Ontario noted that subsequent research determined some plants can absorb the chemicals depending on their concentration, species and soil type. The more recent studies determined that in plants, the chemicals are "not likely" to be harmful to health.
But head south of the U.S.-Canada border, and many government officials have taken a drastically different tone.
For instance, this spring the Maine State legislature passed a suite of laws to tackle PFAS contamination that will ban the use of biosolids on fields, help farmers get their farms and farm products tested and compensate farmers forced to relocate. The state expects to test close to 700 farms and has earmarked close to $77 million to deal with the problem.
Michigan is the only other state to have taken action on the issue and last year set a standard that doesn't allow farmers to put biosolids on their fields if they contain over 150 parts per billion of PFAS. The rule means all sewage sludge needs to be tested before it is put onto fields.
Last October, the Biden administration announced new plans to regulate PFAS, including research into PFAS contamination on farms and in food. In an April report, the Environmental Working Group, an American environmental organization, found that up to 20 per cent of U.S. cropland could be contaminated with PFAS because it was fertilized with sewage sludge.
Still, experts warn it is essential environmentalists and policy-makers tackling PFAS contamination on farms focus on the chemicals, not the application of sewage sludge to fields.
"The nuance is that the application of biosolids to the fields is a sustainable practice," explained Narasimman Lakshminarasimman Meanakshi Se, a PhD student at the University of Waterloo who studies new contaminants and wastewater treatment. If they aren't used as compost on fields, municipal waste managers need to incinerate biosolids or put them in landfills.
"This is a pollution prevention problem rather than a pollution control problem," he said. Testing for PFAS and removing the chemicals from sewage is expensive and, in some cases, nearly impossible. Eliminating PFAS entirely is a much more effective way to tackle the pollution problem. Instead of regulating biosolids, activists and policy-makers need to focus on regulating chemical companies in an effort to reduce the overall volume of PFAS produced and sold globally each year.
If they are ever implemented, rules restricting PFAS production will come too late for farmers like Holmes.
Nearly six months after she was forced to close her farm, she is still trying to get back in business. Her entire herd of milking ewes are contaminated, as are her dairy cows, meaning she cannot sell the milk they produce. The farm is getting by with milk from a new herd of cows and some other products that tests have shown are safe.
Despite the positive signs, she remains wary. Because they are water-soluble and so persistent, if she's not careful, PFAS could pop up anywhere on the farm, adding an "insane level of complication to what we do."
"It's important for people to understand what we're doing to our planet," she sighed. "And that we have the ability to stop."
Comments
On the question of whether using the sludge is a good idea in the first place I recommend the book "Toxic Sludge is Good For You", one chapter of which is all about the fundamental problems with the way we deal with waste, which leads to wastewater treatment concentrating all kinds of pollutants in that sludge, and how it got reclassified from toxic waste to fertilizer so someone could make a buck. I would say this article is unintentionally misleading--it's nice that they've noticed one particular pollutant that turns up in the sludge, it would be nice if steps were taken to stop making that pollutant, but that's the tip of the iceberg.
The fundamental bottom line is, most urban water systems steer storm drain output, including industrial waste water, to the same water treatment plants that receive sewage. And the more efficient the water treatment plants are, the less sludge remains, the more chemicals from the industrial waste water get concentrated in it. But separating the two water systems so sewage treatment plants weren't receiving the industrial chemicals in the first place would cost billions and billions of dollars.
I also recommend the book generally (full title: "Toxic Sludge is Good For You: Lies, Damn Lies and the Public Relations Industry") as a guide to the way the PR industry shapes our understanding of and beliefs about the world. Plus it's funny.