Toxicological potential of metals found in soil of cemeteries in Santa Maria - RS

Abstract

Contamination with toxic elements and cemetery leachate may result when proper geo-environmental and hydro geographic studies are not conducted and cemeteries are dug in soils without appropriate structure and chemical properties. This contamination may percolate through the water table, leading to groundwater contamination, which can dramatically affect natural resources and public health. The toxicity of soil from Santa Maria was evaluated in this context. In addition, concentrations of Al, Ca, Cd, Cr, Cu, Fe, Mg, Ni, Pb and Zn were determined and compared with the tolerance limits established by the National Environmental Council Resolution No. 420 of 2013. Oligochaetas of the Eisenia andrei species were used as bio indicators in the format bioassays-limit test (control versus treatment), in a completely randomized design with three replications, consisting of seven treatments and two levels. At the end of the exposure period, we evaluated the effects of acute toxicity in oligochaetas, considering the median lethal concentration (LC₅₀). The results of acute and chronic toxicity studies in the two analyzed cemeteries (urban and rural) showed toxicity (CL₅₀ 239,88 mg k^-1 e 52,48 mg kg-¹⁾ and interference in the reproductive process of oligochaetas. We detected concentrations of toxic metals that exceeded legally established values.

Keywords:
biomarkers; oligochaetas; toxic metals; toxicity.