EMBARGOED—NOT FOR PUBLIC RELEASE BEFORE:
Monday, April 13, 2015
 3:00 PM US Eastern Daylight Time
 7:00 PM Greenwich Mean Time
Tuesday, April 14, 2015
 4:00 AM Japanese Standard Time
 6:00 AM Australian Eastern Time
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Agricultural insecticides and aquatic biodiversity
Agricultural insecticide contamination of streams and estuaries frequently exceeds
regulatory thresholds, according to a study. High levels of pesticide contamination in aquatic
habitats can reduce aquatic biodiversity, but the degree of pesticide contamination
worldwide has not been evaluated. Sebastian Stehle and Ralf Schulz examined 838 studies
conducted between 1962 and 2012 and covering 2,500 aquatic sites in 73 countries to
evaluate the exposure of surface waters to agricultural insecticides. The authors determined
whether the concentrations of 28 commonly used insecticides representing all major
insecticide classes exceeded threshold concentrations accepted by regulatory authorities at
the sites. The authors found that insecticide contamination occurs rarely in the aquatic
environment, with an estimated 2.6% of the samples containing measurable levels of
insecticides. But at the sites containing insecticides, 52.4% of the detections exceeded
regulatory thresholds. Threshold level exceedances were high even in highly regulated
countries and were pronounced for new-generation insecticides. According to the authors,
changes to pesticide regulations and additional monitoring of surface waters in agricultural
areas around the globe may reduce impacts to surface water biodiversity.
Article #15-00232: “Agricultural insecticides threaten surface waters at the global scale,” by
Sebastian Stehle and Ralf Schulz.
MEDIA CONTACT: Ralf Schulz, Institute for Environmental Sciences, University KoblenzLandau, GERMANY; tel: 0049 6341 28031327; e-mail: <schulz@uni-landau.de>
An image accompanying this article is available.
http://www.eurekalert.org/jrnls/pnas/15-00232.htm
AFTER THIS ARTICLE PUBLISHES, it will be available at
http://www.pnas.org/cgi/doi/10.1073/pnas.1500232112