The sewage sludge that many wastewater treatment facilities lightly treat and then sell in the United States as household fertilizer contains concerning levels of controversial substances.
Last year, the Sierra Club and Michigan Ecology Center discovered toxic per- and polyfluoroalkyl substances, better known as PFAS or “eternal chemicals,” in nine fertilizers made from sludge from purification – commonly referred to as “biosolids” in ingredient lists – and mapped companies selling sludge-based fertilizers and composts for domestic use.
Eight of the nine products tested exceeded the screening guideline for perfluorooctane sulfonic acid (PFOS) or perfluorooctanoic acid (PFOA) set in Maine, the state with the most stringent safeguards for PFAS levels in land-applied sludge. agricultural land. PFOS and PFOA are two of the most dangerous chemicals ever. They are no longer made in the United States, but are still produced internationally and can be imported as consumer goods.
Altogether, there may be as many as 5,000 of these engineered chemical compounds on the market today. They persist in the environment and in our bloodstream because these compounds do not undergo any degradation by light or air or by biological processes. Since they are highly mobile, their contamination spreads through the soil into ground and surface waters and accumulates in fish, shellfish, wildlife and crops.
Levels of PFAS in these household fertilizers and compost raise concerns that the chemicals could contaminate fruits and vegetables and harm those who eat them, according to those behind the 2021 report. Chemicals Forever, which have been linked to cancer, thyroid disease and weakened immunity, cover food packaging, fabrics and waterproof clothing. They are used in electronics, fire-fighting foam, anti-fog sprays, waxes, microwave popcorn bags, some pizza boxes, and countless other items. They seeped into drinking water supplies in Rhode Island and Massachusetts.
Sludge in the garden: toxic PFAS in household fertilizers made from sewage sludge noted that many products made from sewage sludge are labeled as “eco”, “natural” or “organic” – even though biosolids are not allowed to be applied on farms growing certified organic produce.
The Sierra Club and Ecology Center researchers purchased nine fertilizers: Cured Bloom; TAGRO blend; morganite 6-4-0; ProCare Natural Fertilizer; EcoScraps Slow Release Fertilizer; Menards premium natural fertilizer; GreenEdge Slow Release Fertilizer; Earthlife natural fertilizer; and Synagro Granulite fertilizer granules.
Of the 33 PFAS analyzed in the products, 24 were detected in at least one product. Each product contained 14 to 20 detectable PFAS.
Rhode Island Department of Environmental Management (DEM) Wastewater Treatment Facility sludge regulations allow the spreading of sludge as fertilizer and soil amendment.
However, most of the sludge generated in the state is either incinerated or buried in a landfill, according to an agency spokesperson. Domestic sludge – liquid or solid material removed from a septic tank, cesspool, portable toilet or marine sanitation device – is not considered sludge.
Another DEM spokesperson noted that the Environmental Protection Agency (EPA) is currently conducting a risk assessment study for PFAS in biosolids. He said the DEM is “waiting for this work to be completed before making a decision on the matter.”
“As it stands, however, the DEM does not require testing for PFAS in sewage sludge,” he wrote in an email to ecoRI News. “The only municipality testing PFAS in sludge is Bristol, which has a permit with MADEP [Massachusetts Department of Environmental Protection] because Bristol sludge is used as compost in Massachusetts.
Massachusetts has a long-term goal of “virtually eliminating” PFAS in biosolids, but is still developing a screening limit and management plan to achieve that goal. Over two years ago, PFAS have been found in a biosolid fertilizer that the Massachusetts Water Resources Authority has sold for nearly three decades.
Connecticut does not allow the use of biosolids as fertilizer.
the Northeast Biosolids and Tailings Associationa company-backed non-profit organization that promotes the use of sewage sludge and other wastes as fertilizers, soil amendments and energy sources, says sewage, sludge and biosolids are not not sources of PFAS.
“Wastewater treatment processes do not use PFAS chemicals,” according to the New Hampshire-based organization. “Only in a few worst-case scenarios have wastewater and biosolids been implicated in PFAS contamination of water at levels of concern.”
The EPA has a health advisory of 70 parts per trillion (ppt) for PFOA and PFOS in drinking water. The maximum contaminant level in Massachusetts for its six listed PFASs is 20 ppt. Rhode Island is following the federal advisory.
Maine is one of the only states to have guidelines to prevent biosolids from contaminating agricultural land and groundwater. It requires that all biosolids be tested for three PFASs before land application. When concentrations exceed a screening limit of 2.5 parts per billion for PFOA, 5.2 for PFOS and 1,900 for perfluorobutanesulfonic acid (PFBS), agricultural fields should also be tested to ensure that repeated applications did not lead to soil concentrations above the limit.