CHENEY, Washington, October 4, 2006 (ENS) - Treated sewage sludge sold to householders to spray on their lawns and gardens as fertilizer may be adding pharmaceuticals, flame retardants and other chemicals to the land, according to research by Chad Kinney, an assistant professor of chemistry and biochemistry at Eastern Washington University.

Nine different biosolid products, produced by municipal wastewater treatment plants in seven different states - Washington, Arizona, Wisconsin, Kansas, Colorado, Texas and Iowa - were analyzed for 87 different organic wastewater contaminants.

The 87 contaminants represent a cross section of medicinal, industrial and household compounds that enter wastewater treatment plants and may be discharged without being completely metabolized or degraded.

Fifty-five of the contaminants were detected in at least one biosolid product sold by government agencies as lawn-and-garden enhancements. Twenty-five compounds were found in every single one of the samples.

"No matter what biosolid we looked at, there were some of these compounds in it," said Kinney, whose research on the subject was published in online edition of the journal "Environmental Science & Technology."

The U.S. Geological Survey's Toxic Substance Hydrology Program supported Kinney's work, which he began while a postdoctoral fellow with the USGS.

Although government regulators and health officials said there is no immediate risk to public health, the study's authors called for more research on the long-term impact on the environment.

"We've been using biosolids for over 30 years safely," said Peggy Leonard, biosolids program manager for King County's waste treatment division, which makes the product GroCo. "As far as I know, there is no risk."

Thomas Burke, a professor of public health policy at Johns Hopkins University in Baltimore, said Kinney's research is a wake-up call for the U.S. Environmental Protection Agency, which has promoted biosolids for decades because they contain the same nutrients - nitrogen and phosphorus - found in fertilizers.

"I don't think people understood before this that they might be applying pharmaceuticals and disinfectants to their front lawns," Burke said.