Environmental impact of insecticides applied on biotech soybean crops in relation to the distance from aquatic ecosystems.

Aquatic environments located in areas cultivated with biotech soybean were studied. Water and sediment samples were analyzed for insecticides, acute toxicity, genotoxicity, detoxification biomarkers, and fish diversity. Samples were taken in the core area of soybean cultivation in Argentina; all measures were related to the distance between the crops and the streams sampled. Endosulfan (alpha + beta) concentrations as high as 553.33 microg/kg were found in sediments from environments located at 0.15 m from treated fields. Ethoxyresorufin-O-deethylase (EROD) activity and cytochrome P4501A1 (CYP1A1) gene expression in fish showed the highest correlation with the environmental concentration of endosulfan. These biomarkers and mortality of amphipods significantly correlated with the concentration of endosulfan in water and sediment, which correlates inversely with the distance between the crop and streams. The differences with respective controls disappear at distances greater than 5 m. The fish diversity was significantly lower from distances between the margin of the stream and soybean crops, not exceeding 2 m. Copyright 2010 SETAC.