MICHELE NORRIS, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.
ROBERT SIEGEL, host:
And I'm Robert Siegel.
The state of California is taking another look at a common class of pesticide, one that's probably under your kitchen sink. Pyrethroids are a synthetic cousin of a pesticide made from chrysanthemum flowers, and they're in everything from ant spray to dog shampoo. California is now the first state to closely examine the environmental impacts of these common products.
From member station KQED, Tamara Keith reports
TAMARA KEITH: Pyrethroids became the pesticide of choice as more problematic agents like DDT and Diaznon were phased out. Now, between agricultural, commercial and home applications, Californians alone use nearly a million pounds of pyrethroids a year.
Mary-Ann Warmerdam is director of the California Department of Pesticide Regulation. The department is undertaking a rare re-evaluation of more than 600 pesticide products containing pyrethroids.
Ms. MARY ANN WARMERDAM (California Department of Pesticide Regulation): These are viewed as softer materials, easier to use, less toxic to the environment. We would very much like to see these materials continuing to be available to the consumer market. Consumers want these products.
Our concern is, why are these products finding their way into places they shouldn't be?
KEITH: Places like this creek that runs through a Sacramento suburb. UC Berkeley researcher Don Weston is up to his knees in water. Wearing waterproof duck-hunting pants, he sloshes through the creek gathering samples of its muddy bottom, scooping the sediments into a gallon-sized jar.
He's looking for pyrethroids. In an earlier study of this creek, he found enough of the synthetic chemicals in some of the sediments to kill off the small invertebrates he uses in lab tests.
Mr. DON WESTON (Researcher, UC Berkeley): The creek becomes toxic from the point where that tributary enters. So I was going to get a sample around the mouth of where that tributary comes in.
KEITH: When pyrethroids were originally approved for use, it was assumed that they wouldn't hurt aquatic life. That's because they don't persist in the water column. Pyrethroids are, however, drawn to sediments like a magnet, and there they do persist. That's a problem for the tiny mud-dwelling critters that live there, and potentially for the fish that eat those critters.
Weston has taken hundreds of samples of sediments in both rural agricultural creeks and urban creeks. He says fewer than 20 percent of the rural streams were toxic because of pyrethroids. His urban samples are a different story.
Mr. WESTON: Sixty-five, 70 percent of them are toxic in the urban environment, and there's enough pyrethroids to explain the toxicity in every single one of them.
KEITH: In urban streams like this one, he says the toxicity isn't caused by big industry or farms. It's mom and dad and two kids and a dog.
Mr. WESTON: It's just regular suburban living and the pesticides that we use to try to keep the bugs out of our house or off our property.
KEITH: To the San Francisco-based Pesticide Action Network, this re-evaluation of pyrethroids is good news.
Susan Kegley is a senior scientist with the group.
Ms. SUSAN KEGLEY (Pesticide Action Network): I'm hoping that there will be some restrictions on use. And getting the stuff off the market would, of course, be the first choice altogether.
KEITH: That of course isn't the first choice of the 123 companies whose products are up for review.
Mr. PARRY KLASSEN (Coalition for Urban Rural Environmental Stewardship): The writing is on the wall. If people don't figure out how to use these correctly, the government is going to take them away.
KEITH: Parry Klassen is executive director of an industry-funded group called the Coalition for Urban Rural Environmental Stewardship.
He says if people want to continue killing ants and other pests with a quick spritz, there are no good alternatives available.
Mr. KLASSEN: We believe that we can properly use this product or steward this product so it doesn't end up in the streams and in sediments, causing impact.
KEITH: Eventually everyone involved expects some products to be removed from the market. And others will likely have new instructions to limit the potential for run-off.
For NPR News, I'm Tamara Keith in Sacramento.