Friday, June 8, 2007

Blue frogs

Though not actually blue in color (unless they're one of these guys), frogs everywhere are apt to be feeling a bit blue upon hearing last week's news that three widely used organophosphate pesticides (or "OPs") have been found to be even more toxic to frogs than was previously thought.

In a study published last week in the journal Environmental Pollution, scientists at the University of Southern Illinois, Carbondale and the U.S. Geological Survey report that the breakdown products of insecticides diazinon, chlorpyrifos, and malathion are far more toxic to certain native California species of amphibians than the original pesticide chemicals, which are already highly toxic. In other words, these highly poisonous chemicals get even more poisonous to frogs after they enter the body and begin to be digested, or after they've been hanging around in the environment for a while and begin to degrade - 10 times more toxic in the case of diazinon, and 100 times more toxic in the cases of chlorpyrifos and malathion.

Frogs may be a "canary in the coal mine" for pesticides because of their moist, permeable skin, but according to one of the lead researchers on this study, Dr. Gary Fellers, these findings do not bode well for other species, including birds, mammals and humans.

OPs are widely implicated in the declines of several amphibian species in the California Central Valley and in downwind mountain areas that are prone to pesticide drift. U.C. Berkeley scientist Tyrone Hayes has also found that the nation's #2 most popular herbicide, atrazine, can cause hermaphrodism and other serious health effects in male frogs, even at very low levels.

These findings implicate pesticide contamination in a widespread decline in amphibian populations across the country, and even worldwide.

People must heed the warning of these green (and increasingly blue!) canaries in the proverbial coal mine, since we depend on the same water that frogs do, and a growing body of scientific evidence indicates that we are also being affected. Consider the recent finding from a researcher at Indiana University School of Medicine that rates of premature birth in humans are highest each year during the same months that pesticide and fertilizer levels spike in surface water, and lowest in the months when pesticide and fertilizer levels are lowest (link). Or, the finding that that children conceived in Indiana during the months of high pesticide use score lower on standardized tests than children conceived in months with low pesticide use (link).

While municipal drinking water treatment systems kill bacteria that could threaten human health, they seldom remove chemical contaminants - including pesticides and their break down products. Filtering your tap water to remove some impurities is a quick fix, but it is urgent that people act now to keep pesticides out of our waterways. For starters, please support farmers that don't use pesticides by buying locally-grown organic foods whenever you can, and sign up for PESTed's Action Alerts to stay in the loop about pesticide issues in North Carolina, and what you can do to make a difference.

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