SURFACE AND GROUNDWATER POLLUTION BY ORGANOCHLORINE COMPOUNDS IN A TYPICAL SOYBEAN SYSTEM FROM THE SOUTH PAMPA, ARGENTINA

GONZÁLEZ, M.; MIGLIORANZA, K.; SHIMABUKURU V.; QUIROZ LONDOÑO, O. M.; MARTINEZ D.E.; AIZPUN, J.; MORENO J.

Environmental Earth Sciences

Springer

Año: 2012 vol. 65 p. 481 - 491

1866-6280

Organochlorine pesticides (OCPs) use have been restricted or forbidden in Argentina since 1998; being technical endosulfan the last currently OCPs used on the soybean-wheat production. Since they persist in soil for several years after application, OCPs constitute a source of environmental pollution. This work aims to assess OCPs contamination of groundwater (Gw) and streamwater (Sw) in, the Quequén Grande river watershed from south Argentinean Pampas, in relation with the hidrogeological characteristics. OCPs were analyzed in Sw, Gw, surface bottom sediments, soils and boreholes cutting sediments (Cs) by gas chromatograph-electron capture detector.Pesticide distribution in Cs was dependent on the characteristic of the non-saturated zone. Leached pesticides over 3 meters in Cs showed the pattern: HCHs = endosulfan > chlordanes > DDTs, and from 3 to 6 m heptachlor was the main group as a consequence of the past use of this compound in the area, mainly on potato crops. Endosulfan reaches Gw during application season as well as during flooding events while a retard effect was observed for Sw. Levels of - and -isomers were in certain cases above national (7 ng L-1) and international (3 ng L-142 ) limits foraquatic biota protection. Since the endosulfan sulfate metabolite was present in Gw and Sw and due to its high toxicity, it should be considered in the establishment of water quality criteria for human and environment protection.