Pesticides used by farmers in California’s Central Valley could be killing frogs in the Sierra mountains, report researchers. Don Sparling of Southern Illinois University Carbondale found that minute quantities of endosulfan — the active ingredient in many pesticides — was enough kill frogs. “At 0.8 parts per billion, we lose all of them,” Sparling said. 8 parts per billion is the equivalent of a dozen salt grains dissolved in 500 gallons of water. “We always thought there was an association between pesticides and declining amphibian populations, and we’re building up a body of evidence to show this is the case.” Sparling and colleagues found that endosulfan are making their way, likely via wind currents, into critical frog habitat, triggering die-offs among Pacific tree frogs and foothill yellow-legged frogs, which are native to meadows in California’s Sierra Mountains. “The Central Valley is an extremely intense agriculture area, with everything from grapes to peaches, to nuts and tomatoes grown there,” Sparling explained. “Along with that, you have literally hundreds of thousands of pounds of active-ingredient pesticides, this is before it’s diluted, applied each year in this area.” “These pesticides are applied by airplanes and we found that the wind would blow some of it up into the mountains, for instance. In other cases, these chemicals would volatize after being applied, turning into a gaseous state, which could also be picked up and spread into the mountains by wind.” …
Pesticide use linked to dying frogs in California
