Deposition of Potentially Toxic Metals in the Soil from Surrounding Cement Plants in a Karst Area of Southeastern Brazil

Abstract

Cement factories are the main sources of environmental pollutants among the different industrial activities, including soil contamination by potentially toxic metals. The karst region of Southeastern Brazil is known for the implementation of large cement producing facilities. This study aims to evaluate whether there is an increase in the concentration of PTM in the soil surrounding the cement plants and to estimate their harmfulness to both local human population and environment. In total, 18 soil samples were collected from the surroundings of three cement plants as well as four soil samples from areas outside the influence of cement plants and concentration of the following potentially toxic metals (PTM) were estimated: Cd, Pb, Co, Cu, Cr, Mn, Ni, and Zn. The results revealed that all PTM concentrations from cement plant surroundings were significantly higher than PTM concentrations from control areas and no PTM concentrations from CPS or CA soil samples exceeded national and global contamination thresholds. However, Igeo Index indicated low level soil contamination by Pb, Cu, and Cr, as well as high levels for Co. We could not verify significant non-carcinogenic risk to health for any soil sample, but carcinogenic risk analysis revealed different levels of carcinogenic risk among the sampled locations, for both adults and children. Our results indicate that exclusively evaluating the concentration of potentially toxic metals is not enough to verify the potential harmful effects of cement production for the surrounding population. Here we evidence that additional indices, based on both contamination indices and health risk assessments, should be considered for better evaluation of the impacts of cement production activity.