Chemical fractions of toxic metals and assessment of risks on the environment and health in Mugla topsoils

Abstract

In the current study, the chemical fractions of Pb and Cd and total concentrations of these metals in topsoil samples which were collected between 2016 and 2017 in the center of Mugla, which is a small agricultural city in the Aegean Region of Turkey, were determined. Contamination, environmental, and potential human health risks indices were calculated in topsoil samples for Cd and Pb. In order to determine the exchangeable, reducible, oxidizable, and residual fractions of Cd and Pb in topsoil samples, the modified BCR chemical sequential extraction procedure was used. According to contamination and environmental risk indices, only Cd could pose a serious risk for the center, but Pb had no risk. But according to potential human health risk indices in the topsoil samples, no harm to human health was determined for both metals. The results of the study showed that total concentrations of Cd in the topsoil samples in all the locations of the center of Mugla had a uniform distribution. However, the chemical fractions of the metals did not show a uniform distribution and very different fraction values were obtained for Cd and Pb in each location of the city. In addition, it was determined that the concentrations of Cd in the topsoil samples exceeded the maximum permissible limits for some international soil quality guidelines but the concentration of Pb in topsoil samples did not exceed these limit values.