AVALIA??O DA TOXICIDADE AGUDA PARA O ORGANISMO-TESTE Vibrio Fischeri DOS PRINCIPAIS HERBICIDAS E INSETICIDAS APLICADOS NA LAVOURA DE ARROZ IRRIGADO DOS ESTADOS DE SANTA CATARINA E RIO GRANDE DO SUL

摘要

Santa Catarina and Rio Grande do Sul are the largest irrigated rice producing states in Brazil, and are highlighted for their intensive use of agricultural chemicals for the control of undesireable competitors and consumers of the crop. In order to evaluate the toxic potential of these agricultural chemicals, and their effects on non-target organisms, this work sought to determine the EC 20 and EC 50 of the main herbicides and insecticides used in the rice crop, using as a test organism the bioluminescent bacterium Vibrio fischeri . Short duration static tests were carried out (30 minutes), based on the inhibition of luminescence of the bacteria after exposure to the toxic agent. The products tested were the herbicides 2,4-D (DMA 806 BR- dimethylamide), metsulfuron-methyl (Ally), carfentrazone-ethyl (Aurora), bentazon (Basagran), quinclorac (Facet), oxyfluorfen (Goal), bispyribac-sodium (Nominee) and pyrazosulfuron-ethyl (Sírius), and the insecticides betacyflutrin (Bulldock), carbofuran (Furadan), lambdacyhalothrin (Karate) and fipronil (Standak) at maximum concentrations of 100 mg/L (a.i.). The herbicides Ally and Sírius and the insecticides Bulldock and Standak did not present toxicity for the bacterium Vibrio fischeri , as they resulted in an inhibitory effect of less than 20 %. Basagram, Facet, Nominee and Furadam presented toxicity with a EC20 (a.i.) of 40.87 mg/L, 36.00 mg/L, 45.83 mg/L and 3.23 mg/L, respectively, and for the products 2.4-D, Aurora, Goal and Karate, the EC50 values for the active ingredient obtained were 13.90 mg/L, 1.02 mg/L, 19.23 mg/L and 10 mg/L, respectively. Compared with studied carried out with other test organisms, the bacterium V. fischeri and the bioluminescence test presented low sensitivity to the toxicity of the agricultural chemicals.