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Friday, November 16, 2018

EPA's inspector general says processed sewage sludge used as fertilizer might not be safe

The treated sewage sludge that many farmers use as fertilizer might not be safe because not enough is known about hundreds of pollutants found in the stuff, according to a newly published report by the Environmental Protection Agency's inspector general.

"The treated sewage known as biosolids is chock full of nutrients, which is what makes it so good at enriching soil. But it also can be chock full of pollutants, from heavy metals such as mercury and arsenic to pharmaceutical compounds, flame retardants and disease-carrying organisms," Jennifer Dlouhy reports for Bloomberg Quint.

The biosolids are the residue left over after wastewater goes through treatment plants. About half the sludge created annually is incinerated or sent to landfills. The other half is used as fertilizer after undergoing extra treatment to remove more pollutants and make it less appetizing to pests. Fertilizer sludge is tested for pathogens, pollutants that may need to be regulated, and nine heavy metals, including arsenic and mercury. "Although the EPA has consistently monitored biosolids for those nine regulated substances, the agency lacks the data or tools needed to determine the safety of hundreds of other pollutants found in the material, the inspector general found. And while the EPA is reviewing additional pollutants, the agency hasn’t always completed those assessments in a timely manner, the watchdog said," Dlouhy reports.

At least 352 pollutants found in biosolids haven't been fully vetted for safety by the EPA, though at least 61 of them have already been declared hazardous by another federal authority, Dlouhy reports. EPA officials responded to the report with a reminder that the pollutants are not necessarily a threat to public health or the environment.

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