Avaliação ecotoxicológica de metais potencialmente tóxicos das águas do rio Pirajibú por análises de biomarcadores bioquímicos no fígado de girinos de rãs-touro.

Abstract

Environmental contamination of the aquatic environment by metals is a major concern and has received considerable attention in recent decades. Metals, derived from agricultural operations and industrial effluents, can reach different water bodies and produce toxic effects on aquatic organisms and, accumulated in the aquatic biota can represent a health problem of public interest. The present study investigated the presence of metals [Aluminum - Al, Barium - Ba, Cadmium - Cd, Cobalt - Co, Copper - Cu, Chromium - Cr, Potassium - K, Manganese - Mn, Molybdenum - Mo, Nickel - Ni, Strontium - Sr and Zinc - Zn] in the water of the Pirajibú River, Sorocaba, SP and verified the effect of these metals on the liver of bullfrog tadpoles (Lithobates catesbeianus). For this purpose, water was collected from two sites of the river (Montante and Jusante of the industrial area), during the dry period of the year, and the tadpoles were exposed to these waters for 96h. As a control group, tap water from the UFSCar campus Sorocaba was used. For the evaluation of the effects on bullfrogs, the following variables were analyzed in the liver: activity of the antioxidant enzymes: SOD (superoxide dismutase) and CAT (catalase), levels of LPO (lipid peroxidation), PCO (carbonylated proteins) and of MT (metallothionein). The data of the water were compared with the limits established by the resolution of the National Council of Environment (CONAMA) no. 357 of 2005. As results, in comparison with the control group, the CAT activity was higherMOntante and Jusante and the SOD was lower, LPO was lower in Jusante, PCO was higher in Montante and Jusante and there were no significant changes in the concentrations of MT. The results show that although the metals were below the CONAMA resolution limit the acute exposure to Pirajibú River water caused oxidative stress in tadpoles.