Toxic Sludge Fertilizer

According to this New York Times article, research has shown that sewer sludge spread on farmlands often contains toxic chemical concentrations (PFAS) which can enter the human food chain from contaminated crops and livestock.

NOTE: this article was originally published to NYTimes.com on August 31, 2024. It was written by By Hiroko Tabuchi.

For decades, the government has encouraged farmers across the United States to spread sewage sludge on their cropland and pastures. But now there’s a growing awareness that sludge fertilizer can contain heavy concentrations of “forever chemicals” linked to cancer, birth defects and other health risks.

This sludge is a byproduct of the nation’s wastewater-treatment plants. It’s the solid stuff that remains after city sewage is treated. But because it’s essentially concentrated waste, those toxic chemicals, known as PFAS, can become concentrated in it, too.

Here are the key findings from The New York Times’s examination of sludge fertilizer use and the consequences for farmers and the food supply:

Millions of acres are affected.

The fertilizer industry says more than two million dry tons of this kind of fertilizer were used on 4.6 million acres of farmland in 2018. It estimates that farmers have obtained permits to use sewage sludge on nearly 70 million acres, or about a fifth of all U.S. agricultural land.

The sludge is also applied to landscaping, golf courses and forest land. It’s so plentiful that it has even been used to fill up old mines.

Some farmers allege that it killed their animals.

Several ranchers in Texas claim that sewage sludge applied to a neighbor’s fields contaminated their land and contributed to the deaths of horses, cattle and catfish on their property. They are suing the company that provided the sludge. They are also suing the Environmental Protection Agency, saying it failed to regulate the PFAS chemicals in fertilizer.

The company that provided the sludge told The Times that it was “vigorously contesting” the allegations, and that it is simply a “passive receiver” of chemicals that are already in the sludge.

It’s legal, though the E.P.A. is studying the risks.

The E.P.A. regulates pathogens and heavy metals in sewage fertilizer, but not PFAS. For decades, the agency has encouraged the use of sewage as fertilizer.

It is now studying the risks of PFAS in sludge fertilizer, also known as biosolids, in order “to better understand the scope of farms that may have applied contaminated biosolids and develop targeted interventions to support farmers and protect the food supply,” the agency said in a statement.

Elsewhere, the E.P.A. has started to take action. In April, it ordered utilities to slash PFAS levels in drinking water to near zero. The agency now says there is no safe level of PFAS for humans.

Contamination can reach food we eat.

Research has shown that PFAS chemicals can enter the human food chain from contaminated crops and livestock.

In Michigan, state officials issued a warning not to eat beef from a farm that was found to be particularly heavily contaminated. Officials in Maine found PFAS contaminants in milk from animals that had been grazing on land treated with PFAS-laced sewage sludge fertilizer.

Few states have taken action.

Maine is the only state to have banned the use of sewage sludge on agricultural fields. It’s also the only state that is systematically testing farms for the chemicals. Investigators have found contamination on at least 68 of the more than 100 farms checked so far, with some 1,000 sites still to be tested.

Michigan hasn’t conducted widespread testing at farms, partly out of concern for the economic impact on its agriculture industry. It has focused instead on limiting the release of PFAS into waste-treatment plants, to rein in future contamination of sewage sludge fertilizer.