"The biggest surprise was that it took nearly a year to detect the effects of atrazine at 4 parts per billion, which is just 1 part per billion above the maximum allowable level in drinking water set by the U.S Environmental Protection Agency," said Rohr, who presented his findings at a recent workshop organized by the U.S Geological Survey in St. Louis, Missouri.
"What this tells me is that we need to consider the long-term effects of chemicals, and that exposure to atrazine during formative stages might have permanent effects on these salamanders that increases their risk of mortality," he added.
While the mechanism by which atrazine causes elevated mortality remains unclear, Rohr says other scientists have evidence suggesting that this pesticide is an endocrine disruptor.
Such chemicals disrupt the production of hormones that are vital to normal bodily functions. Concentrations of atrazine as low as 0.1 parts per billion have been shown to cause male frogs to develop both male and female organs by altering their production of sex hormones.
Findings from Rohr's study, which was funded by the U.S Environmental Protection Agency, National Science Foundation, and the Kentucky Academy of Sciences, could have implications for global amphibian declines.
"Salamanders, and amphibians in general, are crucial to ecosystems, as both predators and prey. They can be seen as bioindicators of enviro