Environmental hazard of pesticides applied in the border region between Platinum and Amazon Basins at the turn to century XXI

Objective: To reveal the environmental risk of pesticide prescribed in a border region between the Amazon and Platinum Basins, at the turn of the 21st century. Methods: The study used data of agronomic prescriptions for pesticides issued in the biennium of 1999-2000 in 24 cities located in a border region between the Amazon and Platinum Basins, Mato Grosso, Brazil. Results: The most widely used pesticides in the study region are class II (very dangerous) and III (dangerous) in number of prescriptions (N = 2,828, 86.8%) andquantity prescribed (N = 344,765, 90.4%). Among class III pesticides, a strong inversion was observed in the number of prescriptions (N = 1,274; 39.1%) and quantity prescribed (N = 237,319; 62.2%), indicating a lower number of prescriptions, but with higher amountprescribed. The proportion of prescriptions for products amid the various classes of Potential of Environmental Dangers (PPA ranking model, apllied in Brazil) changed over the two years (c2=20,814; DF=3; p < 0,01). The 10 most prescribed products (11 activecompounds) were: glyphosate, 2,4-D, sulfluramid, chlorimuron ethyl, fipronil, diuron, paraquat, methamidophos, carbofuran, chlorpyrifos and lambda-cyhalothrin, and seven of them were ranked as PPA class I or II. Conclusions: The ratio between the number of pesticide prescriptions and the quantities prescribed among the various classes of PPA showed alteration over crop years. The most reported products in this border region were classified as the most dangerous ones, with diverse mechanisms of action and potential risksto living organisms. This suggests the need to define specific policies and carefully designed strategies to prevent environmental disaster in this region