Índice para a avaliação do risco de contaminação da água por pesticidas: desenvolvimento e validação

Abstract

Since surface and ground water are strategic and vulnerable environmental compartments, their contamination by pesticides can cause significant damage to man and ecosystems. The objective of the present paper was to develop a simple and robust index to estimate the risk of water contamination by pesticides, in different agronomic and environmental settings, and to validate it at the field level. The risk of contamination (R) was defined as the product of the environmental vulnerability of the site (V) and the contamination potential of the pesticides (Pc). The vulnerability is calculated using the clay content of the soil, the distance to the nearest stream, and the type of soil management. The contamination potential is the product of the pesticide mobility, persistence, and toxicity to man and fish. A validation experiment was carried out in a soybean field in the Distrito Federal, Brazil. In that study, the glyphosate concentration on the runoff of the slope was compared with the behavior predicted by the index. Furthermore, the glyphosate concentrations in the river downstreamr were compared with the risk calculated by the index. In both cases, the ARCA index correctly predicted the values and trends obtained in the field study. However, considering the limited scope of the experiment, it is recommended that further studies be performed to better assess model validity