Agricultural insecticide contamination threatens U.S. surface water integrity at the national scale

Insecticides are applied in large volumes across the United States to protect agricultural crops from insect pests. As has been shown before through studies e.g. by the USGS or the U.S. EPA, these substances can be transported from agricultural fields into adjacent water bodies via various pathways where they have profound adverse effects on both water quality and biodiversity. Therefore, insecticides have to pass an elaborated environmental risk assessment procedure before being sold and applied to crops. During this process, regulatory threshold concentrations are derived, which should not be surpassed, in order to prevent adverse effects in non-target environments such as surface waters. These thresholds were compared to actual field concentrations of 32 commonly applied insecticides, obtained from 259 peer-reviewed publications reporting insecticide concentrations in more than 600 water bodies in the U.S.