Resumo

RONDON-BARRAGAN, Iang S; RAMIREZ-DUARTE, Wilson F  e  ESLAVA-MOCHA, Pedro R. Assessment of toxic effects and lethal concentration 50 of surfactant Cosmoflux^® 411F on juveniles of cachama blanca (Piaractus brachypomus). Rev Colom Cienc Pecua [online]. 2007, vol.20, n.4, pp.431-446. ISSN 0120-0690.

In Colombia, surfactant Cosmoflux^® 411F is used for the fumigation of illicit crops in order to improve the glyphosate herbicide activity. The use of Cosmoflux^® 411F is not supported by toxicological surveys. The aims of this study were to determinate the anatomopathological lesions due to the exposure to Cosmoflux^® 411F and to establish lethal concentration 50 (LC₅₀) to 96 hours in cachama blanca (Piaractus brachypomus). Juveniles of cachama blanca (~40 g) in two assays were used: 1) sublethal toxicity (n= 126) and 2) determination of LC₅₀ (n=84). Sublethal toxicity assay concentrations were: 0 mg/l (Treatment 0) 0.17 mg/l (Treatment 1), 0.34 mg/l (Treatment 2), 0.68 mg/l (Treatment 3), 1.36 mg/l (Treatment 4), and 2.72 mg/l (Treatment 5); through semi-static system. For the determination of LC₅₀ of Cosmoflux^® 411F 3000, 3450, 3900, 4350 y 4800 mg/l concentrations were used. LC₅₀ was 4417.99 mg/l. Animals showed slight decrease in swimming activity. At necropsy examination were found paleness in liver and whitish material accumulation in top of gill filament. Histopathologically, it was found fatty degeneration and hepatocyte vacuolization, epithelial cells, chloride cells and mucous cells hyperplasia, enterocyte vacuolization, increase in the expression of melanomacrophage centres in kidney, gliosis, neuronal degeneration and infiltration of eosinophilic granule cells/mast cells in telencephalon. With exception of central nervous system lesions, the findings are according to the reported in literature about surfactant exposure in fish. Central nervous system effects can have consequences on feeding, reproductive and social interactions, due to close telencephalon/olfactory system relationship, being necessary to deep in research to these processes. In same way, liver, gills and skin are target organs of toxic action of this xenobiotic. LC₅₀ is high (4417.99 mg/l) compared with that reported for other nonionic surfactants. Nevertheless, the lack of information about the structure of surfactant restrict the analysis of the dynamic and implications of xenobiotic in the generation of lesions, although, a synergic effect on the mixture is foreseen.

Palavras-chave : anatomopathological lesions; cachama blanca; Cosmoflux^® 411F; environmental toxicology; LC₅₀; non-ionic surfactants.

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