Toxic effects of phytosanitary surfactants for jewel tetra

Toxic effects of phytosanitary surfactants for jewel tetra (Hyphessobrycon eques). Surfactants are amphipatic molecules that reduce the surface tension of water and make up the inert components of pesticide formulations. Thus, the objectives of this study were: to estimate the lethal concentration (LC(I)50;96h); classify and evaluate water quality during testing of the following surfactants: Agral®, Aterbane ®BR, Ag-bem®, Energic®, Fixade® and Gotafix® for jewel tetra (Hyphessobrycon eques); and the signs of intoxication in the animals. For this, the fish were acclimated for ten days in the bioassay room. The animals were exposed to the surfactants in an entirely randomized design with three replications. The LC(I)(50;96h) of surfactant Agral® was 3.29 mg [L.sup.-1]; Aterbane® BR 8.21 mg [L.sup.-1]; Energic® 2.34 mg [L.sup.-1]; Gotafix® 4.37 mg [L.sup.-1]; Fixade® 3.38 mg [L.sup.-1]; and Ag-bem® 34.95 mg [L.sup.-1]. The variables of water quality were unchanged. The fish showed an increase in the opercular beating after exposure; 4 and 24 hours, loss of gasping ability; 48 hours, slow opercular beating; and 72 and 96 hours later, recovery. The surfactants Energic®, Agral®, Gotafix®, Aterbane® BR and Fixade® can be classified as moderately toxics, and Ag-Bem® as slightly toxic for H. eques; this organism shows similar intoxication signs for all surfactants. Keywords: ecotoxicology, fish, water quality, behavior. Os surfactantes sao moleculas anfipaticas que reduzem a tensao superficial da agua e fazem parte dos componentes inertes das formulacoes de produtos fitossanitarios. Assim, os objetivos deste trabalho foram: estimar a concentracao letal (CL(I)(50;96h)); classificar e avaliar a qualidade da agua durante os testes de toxicidade aguda dos surfactantes: Agral®, Aterbane® BR, Ag-Bem®, Energic®, Fixade® e Gotafix® para o peixe mato grosso (Hyphessobrycon eques); e os sinais de intoxicacao nos animais. Para tanto, os peixes foram aclimatados por dez dias em sala de bioensaio. Os animais foram expostos aos surfactantes em DIC com tres repeticoes. A CL(I)(50;96h) do surfactante Agral® foi 3,29 mg [L.sup.-1]; do Aterbane® BR, 8,21 mg [L.sup.-1]; do Energic®, 2,34 mg [L.sup.-1]; do Gotafix®, 4,37 mg [L.sup.-1]; do Fixade®, 3,38 mg [L.sup.-1] e do Ag-Bem®, 34,95 mg [L.sup.-1]. As variaveis de qualidade da agua nao foram alteradas. Os peixes apresentaram aumento do batimento opercular apos a exposicao; 4 e 24h, perda da capacidade de arfagem; 48h, batimento oper