Análise dos teores de elementos potencialmente tóxicos no solo de Serafina Corrêa - RS

Abstract

To define whether a particular type of soil has not been contaminated, it is necessary to identify the levels of potentially toxic elements present in this soil under natural conditions, without anthropogenic influence. These reference values are a basis for determining Soil Quality Guiding Values. Therefore, a definition of natural levels of potentially toxic elements in soils is essential for the preparation of legislation that supports the monitoring and remediation of contaminated areas and that is compatible with the pedological reality of the place. In this scenario, the objective of this study is to identify the natural contents of hexavalent chromium (Cr (VI)), lead (Pb) and cadmium (Cd), for the soils of the city of Serafina Corrêa in the state of Rio Grande do Sul. The results were correlated with CONAMA Resolution No. 420/2009, Cadmium contents were higher than the Prevention and Investigation Values, for both depths analyzed, having as maximum contents found 6.68 mg / kg for surface and 6, 03 mg / kg for subsurface. As well as contents of hexavalent chromium, Cr (VI), higher than the Intervention Value established by CETESB (2016), varying in the range of 6.91 mg / kg for surface and 3.57 mg / kg for subsurface, corroborating the need greater knowledge of regional diversities for the development of national standards. For the element Lead (Pb), the values found are within the limit established by legislation. Because high levels were found in agricultural areas and also in forest areas, it was not possible to identify whether they are of contribution from the source material or of anthropic action, especially due to the fact that the values in the subsurface horizons are also high. Finally, this work identifies the need to establish Reference Values for each region of Rio Grande do Sul, as these are natural levels, those used by the environmental inspection bodies in assisting and making decisions when it comes to disposal of industrial by products in the soil, as well as determining whether an area is contaminated or not.