In the United States, approximately 20 million acres of farmland may be contaminated by PFAS-polluted sewage sludge used as fertilizer. This is revealed in a new report by environmental researchers from the Environmental Working Group (EWG).
Dozens of American industries use PFAS in thousands of products and often discharge their liquid industrial waste into the sewer system, leaving residues in the sewage sludge.
The Environmental Working Group's (EWG) analysis illustrates the extent of farmland contamination resulting from sewage sludge or biosolids. So far, in the U.S., there is no legal requirement to test sewage sludge for PFAS. Health agencies warn that this practice threatens the food supply.
PFAS is a collective term for roughly 9,000 chemical compounds used to make products heat-, water-, or stain-resistant. They are known as "forever chemicals" because they do not naturally break down. These chemicals have been linked to cancer, thyroid disruption, liver problems, and birth defects.
"We do not fully know the extent of PFAS contamination in sludge because the U.S. Environmental Protection Agency (EPA) has not prioritized monitoring it by local governments," said EWG director Scott Faber.
Sludge is the byproduct of wastewater treatment, which is a mix of human waste and industrial waste. Removing sludge can be costly, so the waste management industry increasingly processes it as fertilizer rich in nutrients for plants.
EPA data show that since 2016, billions of pounds of sludge have been used as fertilizer. It is estimated that annually, 60% of sludge from U.S. sewage treatment plants is spread on farmland or other fields.
In two U.S. states where waste and sludge are tested for PFAS, a few farms have already been closed due to field contamination. The chemicals have been found in crops and livestock, and the public health costs are still unknown.