Integrated approach for the assessment of impacts from pesticide use in transgenic crop productive systems in the Pampa´s plains of Argentina. Part 3: Biological effects assessment on non-target aquatic-terrestrial biota

CARRIQUIRIBORDE P.; NATALE G.; SOBRERO M.C.; MARTIN M.L.; CAJADE R.; STREITENBERGER J.P.; ARNAL M.; RONCO A. E.

Vilnius, Lituania

Simposio; 11Th International Symposium on Toxicity Assessment; 2003

Institute of Botany, University of Vilnius

Prediction of long term effects on ecosystems from productive activities and the potential impacts on humans should be considered at the time of introducing technologies in different sectors. Biological impacts on vertebrates (amphibians and fish) and vascular plants (riparian and aquatic) from the production of herbicide resistant transgenic crops in the Pampa´s region from field and laboratory studies are reported here. Field characterizations carried on at a local water creek scale included cover-abundance (Domin-Krajina scale) plant census by species, measurements of biomass and chlorophyll content, population monitoring for fish and amphibians, added of in situ caged population experiments in relation to the spray of pesticides and rain events. Laboratory investigations were oriented to the assessment of fish and amphibian native species sensitivity to pesticide active ingredients, formulated pesticides and spray mixtures by means of standardized toxicity tests. Effects on the creek plant community and caged duckweed in the field indicate impacts on the photosynthesis, and of biomass on the strata closest to crop fields. No significant differences in field experiments of mortality or changes in community and population structure of fish were observed after each pesticide application in sampling sites. Caged fish and tadpoles did not show effect on mortality after cypermethrin+glyphosate spraying. However, an abnormally high number of deaths and narcotized fish and tadpoles in shallow up stream zones in addition with an increment of death organism drift were observed after the application of the phosphorate insecticide chlorpirifos. Results indicate that the acute effect of the pesticides used for soybean - corn crop was local, however it represents and additional pressure and possible selection factor on the natural fish and amphibian populations that should be assessed attending possible sublethal and accumulative effects. The actual impact of pesticide application strongly depends on the managerial ability of the farmers and  therefore environmental hazard could be improved if explicit broadcasting programs are implemented.