Assessment of insecticide contamination in runoff and stream water of small agricultural streams in the main soybean area of Argentina.

JERGENTZ S,; MUGNI H,; BONETTO, C.; SCHULZ R,

CHEMOSPHERE

Elsevier

Lugar: Amsterdam; Año: 2005 vol. 61 p. 817 - 826

0045-6535

Abstract The first order stream Brown and the second order stream Horqueta located in the main area of soybean production of Argentina were studied (assessed?) for insecticide contamination caused by runoff from nearby soybean fields. In sediments, suspended particles and water the most sold insecticides in Argentina endosulfan, chlorpyrifos and cypermethrin were analyzed. Endosulfan, chlorpyrifos and cypermethrin, the insecticides most commonly used in the soybean production, were analyzed in water, sediments and suspended matter. Highest concentrations measured in of suspended particles were 318 µg/kg for of endosulfan in Horqueta, (and) 226 µg/kg chlorpyrifos and 13.2 µg/kg cypermethrin in Brown. In runoff sediments chlorpyrifos appeared with concentrations of 150 µg/kg and cypermethrin with 53 µg/kg in Horqueta. (Whereas cypermethrin concentrations in the suspended particles were relatively low), Cypermethrin concentration in the stream water of Brown reached 0.7 µg/L. The highest chlorpyrifos concentration in stream water was 0.45 µg/L in Brown (while endosulfan was not detected in the water-phase). In runoff water highest concentration of 0.3 µg/L were found for chlorpyrifos in Horqueta and 0.49 µg/L for cypermethrin in Brown. The first order stream Brown showed higher concentration (of current-used insecticide) in the water phase than the second order stream Horqueta. Smaller streams are more in contact with the surrounding fields and have a higher bank surface with the nearby ecosystems. Contamination in this area has a higher impact on the stream ecosystem.