The term “biosolids” was coined to cover the more visually disgusting term of sewage sludge, a product used by farmers as fertilizer on agricultural land. This under-publicized threat to human health is generated during the treatment of domestic waste and contains a cocktail of hazardous substances discharged into the sewer system.

Combined sewer systems are an underground network of pipes designed to dry out streets by collecting rainwater, domestic sewage and industrial wastewater in the same pipe. When sewer lines run directly into factories, their waste is combined with the city’s sewage treatment plants, making it exempt from EPA regulation.

This combination of industrial and human waste is collected at wastewater treatment plants where the solids are removed, the water treated and then released back into the environment. The sewer sludge may be burned, dumped at a landfill or processed into biosolids.

What Are Biosolids?

According to the EPA,¹ biosolids result from the treatment of domestic sewage at a treatment facility where it is processed and residuals are recycled. The sewage is then applied as fertilizer on agricultural lands. According to the EPA,² “Biosolids are treated sewage sludge. Biosolids are carefully treated and monitored and must be used in accordance with regulatory requirements.”

While this statement makes it seem biosolids are safe for application on agricultural lands, recent findings in dairy products³ and a report from the Office of Inspector General (OIG)⁴ demonstrates they are not.

The production of biosolids begins with sewage from wastewater treatment plants. Research from the U.S. Geological Survey (USGS)⁵ has shown household chemicals and drugs are found in biosolids originating from wastewater treatment plants, as these plants are unable to eliminate the compounds.

USGS scientists⁶ found relatively high concentrations of active ingredients of drugs and chemicals in biosolids. The researchers purchased or obtained nine different biosolids and analyzed them for 87 organic chemicals, finding 55 were detected in measurable amounts and as many as 45 were found in a single sample.

Additionally, the nine samples were more similar than they were different, meaning although they were produced using a variety of treatment processes and from different geographical areas, the contaminants and relationship to each other did not vary greatly. Although the EPA states biosolids are harmless, chemicals linked to cancer are being milked from dairy cows in Maine.⁷

Tainted Milk Highlights Hidden Threat to Food Supply

Public advocates in Maine are now calling for the ban of biosolids as fertilizer after finding it destroyed a dairy farmer’s living and polluted a public water supply. Beginning in the late 1980s, Fred Stone began spreading biosolids over his hayfields that fed his dairy cattle.

Stone said he didn’t know the sludge could be contaminated with PFAS, chemicals associated with cancer, liver damage, low birth weight and hypothyroidism.

Two years after discovering milk from his dairy cows was contaminated with PFAS, he has been dumping 100 gallons or more of fresh milk daily, as the cows continue to produce milk with lingering contamination. He estimates he’s losing up to $450 a day. During a media conference at his farm, Stone said:⁸

“The toxic chemicals that I never used and had never even known about until two years ago contaminated my cows — which I really take exception to — and ruined my farming operation and hurt my family. I want the state of Maine to make sure that no other farming families have to go through what’s happening to us. Believe me, I would not wish this on my worst enemies.”

Although a task force has been created to study the degree of PFAS contamination in Maine, advocates are urging the administration to aggressively end the use of biosolids and any PFAS chemical use in products in Maine. Patrick MacRoy, deputy director of the Environmental Health Strategy Center suggests:⁹

“It seems highly unlikely that Mr. Stone’s farm is the only one with PFAS contamination from sludge. All of the evidence suggests that this is but the tip of the toxic iceberg. There are likely other farms — dairy or otherwise — with similar contamination. Until the tests are done, that is the only safe assumption we can make.”

This tip of the iceberg is a far cry from the EPA’s claim biosolids are safe for use and their continued promotion of the sewer sludge as fertilizer on agricultural lands where chemicals are absorbed into the plants.