Humans do not operate in a vacuum. Everything in this world is connected. Every action we take has a consequence, even though it might not be obvious, or occur in the same place.
Nothing reinforces this more than a recent report that found that remote ponds in the Sierra Nevada mountains are contaminated with pesticides from up to 100 miles away in California’s Central Valley, which is hurting the native frog population.
According to U.S. Geological Survey researchers, trace amounts of agricultural chemicals are making their way over long distances, infiltrating national parks and other public lands where wildlife are supposed to be relatively safe from the outside world.
The study, published recently in Environmental Toxicology and Chemistry, examined pond-breeding frogs living in high elevation areas that are downwind of California’s highly agricultural Central Valley. Analysis of frog tissue, pond water and sediment revealed the presence of 10 distinct chemicals, including residues of DDT, an insecticide that has been banned for more than 40 years.
“Two fungicides, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected pesticides in tissue samples,” states the study abstract. “Significant spatial differences in tissue concentration were observed, which corresponded to pesticide use in the upwind counties.”
Despite what the agricultural industry might want us to believe, the impact of pesticide use is not limited to lands and waterways immediately surrounding the application site. Soil,water and wildlife living up to 100 miles away can still suffer the consequences of the heavy use of these toxic chemicals.
Over the past decade, scientists have noted an alarming decline in U.S. amphibian populations. According to a study published earlier this year, researchers were baffled to learn that “even the species of amphibians presumed to be relatively stable and widespread are declining. And these declines are occurring in amphibian populations everywhere, from the swamps in Louisiana and Florida to the high mountains of the Sierras and the Rockies.”
Current research seems to be the beginning of an answer to the mysterious disappearance of these animals. ”Documenting the presence of environmental contaminants in amphibians found in our protected federal lands is an important first step in finding out whether the frogs are experiencing health consequences from such exposure,” says Patrick Kleeman, a USGS amphibian ecologist who collected the frog samples, in a press release. “Unfortunately, these animals are often exposed to a cocktail of multiple contaminants, making it difficult to parse out the effects of individual contaminants.”
Image via USGS