Fertilizer levels that the EPA says are safe for drinking water can kill some species of frogs and toads, according to a new study published in the journal Environmental Toxicology and Chemistry. Oregon State University researchers were surprised to find that some tadpoles and young frogs raised in water with low levels of nitrates typical of fertilizer runoff ate less than frogs in clean water, developed physical abnormalities, suffered paralysis, and died prematurely. “We’re looking at levels of nitrates so low we didn’t think we’d get any effect,” said Andrew Blaustein, a zoologist and expert on global amphibian declines. Fertilizer runoff may also be encouraging the growth of algae that feeds tiny parasitic flatworms called trematodes, blamed for causing deformities in frogs around the U.S. “The question I have to ask is, are you comfortable drinking water with levels of fertilizer that kills off frogs?” Blaustein said. (Uh, that’d be a no.)