U.S. regulators on Tuesday added to growing concerns about the long-standing practice of using sewage sludge to fertilize farmland, releasing a report warning that chemicals contaminating the sludge pose heightened human health risks for cancer and other illnesses.
The U.S. Environmental Protection Agency (EPA) said two types of hazardous per- and polyfluoroalkyl substances (PFAS) widely found in sewage sludge, a byproduct of wastewater treatment, can contaminate the milk, eggs and meat that come from farm animals raised on agricultural land where the sludge has been applied.
Those “exposure pathways” are among multiple ways in which people can be at risk, the EPA said.
The agency focused on perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), two well-studied types of PFAS chemicals linked to testicular and kidney cancer as well as liver problems.
The EPA last spring designated PFOS and PFOA as hazardous substances under the so-called Superfund law and announced the first legally enforceable limits for the two chemicals and four other types of PFAS in drinking water.
The EPA said that though the majority of U.S. food crops are not grown with the use of sewage sludge as a soil conditioner or fertilizer, because of the “extreme persistence” of PFOA and PFOS in soils, land where sewage sludge was applied years ago may still be contaminated.
The agency’s draft risk assessment, which was made publicly available on Jan. 14, said that “under certain scenarios and conditions,” land-applying or disposing of sewage sludge containing 1 part per billion or more of PFOA or PFOS “could result in human health risks exceeding the agency’s acceptable thresholds for cancer and noncancer effects.”
The draft assessment models health risks for people who live on or near contaminated sites or who eat primarily food or drinking water from PFAS-contaminated areas.
The report will be available for public comment over a 60-day period and may help the agency determine regulatory actions it might take under the Clean Water Act, said the EPA.
Hellbound and Down 