From Baltimore, at a meeting of the Society of Environmental Toxicology and Chemistry
Breezes crossing California's agricultural heartland, the Central Valley, can ferry farm chemicals to elevations high in the Sierra Nevadas. Mountain-water concentrations of endosulfan—a much-used Central Valley insecticide—are strong enough to threaten certain frogs and toads, a new laboratory study shows.
Donald W. Sparling, a wildlife toxicologist at Southern Illinois University in Carbondale, airlifted amphibian eggs collected at relatively pristine Sierra Nevada sites to his lab, where he then incubated them to adulthood in water that was clean or treated with endosulfan at between 0.007 and 15 parts per billion (ppb). Other researchers have recorded concentrations of the pesticide in mountain ponds of around 0.3 ppb, he says.
The highest concentration killed every exposed animal among all three species tested. At around 3 ppb, half of the Western toads