The herbicide atrazine is more likely to kill developing amphibians when it is highly diluted than when it's much more concentrated in aquatic environments, a new study suggests. Although counterintuitive, the finding is consistent with some controversial past research on atrazine and studies showing that other hormonally active compounds are most damaging at trace concentrations.
Atrazine, the most commonly used weed killer in the United States, shows up across the environment. Typically applied to crops in spring, it lingers in aquatic habitats for months.
Scientists who have looked for biological effects of the contaminant have reported inconsistent results. Some scientist