New Data on Concentration of Chemicals in Wastewater Residue

New data show that the sludge produced by sewage treatment plants contains a wide variety of toxic metals, pharmaceuticals, flame retardants, and other compounds, including some antibiotics in surprisingly high concentrations.

That's significant because every year more than half of the roughly 7 million metric tons of these so-called biosolids produced in the United States are applied as fertilizer to farm fields.

"Whether the concentrations of these chemicals pose any health threat isn't known," according to an article in ScienceNOW Daily News.

In the next year, the U.S. Environmental Protection Agency expects to complete risk assessments on 10 chemicals in the new data.