Pesticide pollution in American streams has dropped over the last 20 years according to a new report from the U.S. Geological Survey, but scientists say aquatic life is still at risk.
Changes in regulation and the development of less toxic herbicides and insecticides have reduced the risk pesticide pollution poses to humans. However, the pesticide levels in some regions were high enough to cause harm to plants and animals that live in streams.
Many newer pesticides require smaller doses than previous generations. The study’s lead author Wes Stone says that could have an impact in the overall detection of chemical levels.
“Some of the older pesticides are detected less frequently and the newer pesticides are detected more frequently in the streams,” says Stone.
Some of the most used pesticides weren’t included in the study, like glyphosate, sold under the brand name RoundUp. Stone says many compounds are difficult or expensive to test for and track.