Popular insecticide detected in suburban stream beds

For the first time, researchers have detected high concentrations of a popular insecticide in suburban stream sediments, raising concerns about its effects on aquatic life.

Pyrethroids, the active ingredient used in most home and garden insecticides, have been on the market for years. Although the compounds are considered potentially less harmful to humans than other insecticides, surprisingly little information is available about their long-term impact on the environment, according to Donald Weston, Ph.D., an adjunct professor of ecotoxicology at the University of California, Berkeley.

The finding, by Weston and others, was published online Oct. 19 by the American Chemical Society’s journal, Environmental Science & Technology. A print version of the article is scheduled to appear in the journal’s Dec. 1 issue.

Nearly all of the sediment samples Weston and his colleagues gathered from streams bordering a Roseville, Calif., neighborhood (a suburb of Sacramento) contained enough pyrethroids to eradicate a small bottom-dwelling crustacean called Hyalella azteca.

“These results indicate that monitoring for pyrethroids in urban and suburban streams is overdue, and the public, regulators, and the scientific community should give greater consideration to the potential effects of residential use of pyrethroids on aquatic systems,” Weston and his colleagues conclude.