Environmental contamination levels based on geochemical properties of soils from direct influence areas of hydroelectric power plants.

Soils are extremely important in the assessment of contamination and pollution of aquatic and terrestrial ecosystems. This article aimed to evaluate the effects of potentially toxic elements (PTEs) in soils from direct influence areas of hydroelectric power plants. The Foz do Rio Claro hydroelectric power plant, in the Goiás State/Brazil, was used as enterprise model for referencing other studies about environmental pollution and impact around the world. The PTEs evaluated were cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), and mercury (Hg), in 10 different points of the study area. Soil concentrations were compared to the list of soil guiding values provided by Conama Resolution and Cetesb, which have reference values for prevention and investigation of soils. The concentrations of Cu, Zn, Ni, and Cd at the sampling point 06 were higher than soil backgrounds, with maximum values of 222, 103, 40.3, and 13 mg kg⁻¹, respectively. Detailed qualitative evaluation of contamination levels was performed from the geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (CF), and pollutant load index (PLI). In general, the elements Cu, Ni, and Zn in relation to the guiding values showed concentrations lower than the value of investigation, and Cd showed concentrations higher than the value of investigation. According to Igeo, EF, CF, and PLI for Cd, the impacts of this PTE are high and the level of environmental contamination in soils is significant and harmful to the biota. Finally, hydroelectric power plant areas need to be monitored and remediated to avoid pollution and impact for the environment. [ABSTRACT FROM AUTHOR]