Efeitos de elementos metálicos na saúde de Physalaemus Cuvieri (anura: leptodactylidae) e na qualidade da água próximo a rodovia

Abstract

Roads are sources of pollutants that can affect aquatic environments and, consequently, the health of organisms that depend on water to survive and reproduce. Among the substances with polluting potential are metallic elements. By exceeding the carrying capacity of theenvironment, metallic elements become a source of environmental pollution, presenting themselves as substances with harmful and bioaccumulative properties. This study aimed to evaluate the effect of Al and Zn on the health of amphibians native to the southern region of Brazil and analyze the effect of the presence of roads on the occurrence of metallic elements in water. For ecotoxicological analysis, bioassays were carried out for 14 consecutive days exposing Physalaemus cuvieri (crying frog) tadpoles to aluminum sulfate and zinc sulfate. The tests were carried out in glass containers, using different concentrations of aluminum (0.10 mg L-1 0.20 mg L-1 and 0.30 mg L-1) and zinc (0.18 mg L-1, 0.27 mg L-1), in triplicate. The results of the bioassay data demonstrated that Al and Zn did not cause lethality, but interfered in the development of tadpoles, especially by inducing differences in mass and length and increasing the neutrophil/lymphocyte ratio, an important indicator of animal stress. The study on the presence of metals on roads was carried out on the banks of the RS-135 road, between the municipalities of Sertão and Erechim in the north of the State of Rio Grande do Sul. Water samples were taken from nearby water sources with or without the influence of the road. At each point, two water samples were collected. The estimation of the presence and concentration of metallic elements was carried out using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The presence and concentration of the elements Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, Zn were evaluated. The results shown that proximity with roads had an influence on the concentration of metals in the waters around. The waters near roads had greater concentration of metal elements when compared to other areas, mainly Ca, Mg and Na.