In the United States, some 20 million acres of cropland may have been contaminated by PFAS-contaminated sewage sludge that has been used as fertilizer. This is according to a new report by environmental researchers at EWG.
Dozens of American industries use PFAS in thousands of products and often discharge their liquid industrial waste into the sewage system, after which the residue ends up in the sewage sludge.
The Environmental Working Group (EWG) analysis charts the magnitude of cropland contamination from sewage sludge or biological solids. Until now, there is no legal provision in the US for sewage sludge to be tested for PFAS. Health authorities warn that the practice threatens the food supply.
PFAS is a collective name for approximately 9,000 chemical compounds that are used to make products resistant to heat, water or stains. They are known as "forever chemicals" because they do not break down naturally. These chemicals have been linked to cancer, thyroid dysfunction, liver problems and birth defects.
“We don't know the full scope of PFAS contamination in sludge because the US environmental agency EPA has not made it a priority for local governments to monitor,” said EWG Director Scott Faber.
Sludge is the byproduct of the wastewater treatment process which is a mix of human feces and industrial waste. Disposing of sludge can be expensive, so the waste management industry is increasingly turning it into fertilizer that is rich in plant nutrients.
Figures from the EPA environmental agency show that more than billions of kilograms of sludge have been used as fertilizer since 2016. It is estimated that 60% of the sludge from the US sewage treatment plants is spread on cropland or other fields every year.
In two American states where the waste and sludge are checked for PFAS, several farms have already been closed due to contamination of fields. The chemicals have been found in crops and livestock, and the public health costs are still unknown.