Insecticides Pose 'Excessive Threat' To Waterways

Insecticides pose an "excessive threat" to the health of waterways and can be found in concentrations that breach regulatory limits by considerable amounts, according to a new study.

The study, published last month by Proceedings of the National Academy of Sciences, noted that very little is known about the effect of insecticides on water quality—despite widespread use of insecticide by farmers around the world. The researchers crunched data available from previous scientific studies.

"Our data show, for the first time to our knowledge at the global scale, that more than 50% of detected insecticide concentrations exceed regulatory threshold levels. This finding indicates that surface water pollution resulting from current agricultural insecticide use constitutes an excessive threat to aquatic biodiversity," the study said.

The authors called for new regulations to protect waterways. "Overall, our analysis suggests that fundamental revisions of current regulatory procedures and pesticide application practices are needed to reverse the global environmental impacts of agrochemical-based high-intensity agriculture," the report said.

Many of the insecticides studied in this report may pose a health threat to humans. The researchers focused on 28 insecticides commonly used on farms, including organophosphates as well as pyrethroids.

"The researchers checked the scientific literature for any data they could find on levels of these 28 insecticides in 'surface waters' (such as lakes, ponds, streams and creeks) near agricultural fields across the globe. Their analysis uncovered 838 studies, capturing data from 2,500 aquatic sites across 73 countries between 1962 and 2012," the Washington Post reported.

They compared the data to regulatory thresholds set by the U.S. and the European Union.

"In the end, out of these 11,300 values, more than half of them (52 percent) breached U.S. or E.U. limits, the researchers found. These breaches occurred not just in countries with weak regulatory systems but, in similar amounts, in countries with well-established regulatory systems such as the United States, Canada, Australia, EU nations and Japan," the Post reported.

The study, led by Sebastian Stehle and Ralf Schulz at Germany's University Koblenz-Landau, showed that insecticide contamination is rare but a major threat when it occurs, Agence France-Presse reported.

"Of the some 2,500 aquatic sites covered, just 2.6% of the samples contained measurable levels of insecticides," the report said.

For more on source water contamination, visit Water Online's Contaminant Removal Solution Center.