Contamination and risk assessment of heavy metals in coastal sediments from the Mid-Black Sea, Turkey

This study investigated contamination and ecological risks caused by selected heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, etc.) in the Mid-Black Sea coastal sediments and their effects on human health. The pollution levels were evaluated using comprehensive ecological and pollution indices to quantify their exposure risks posed to human health using the United States Environmental Protection Agency risk assessment model. The result revealed that the mean concentration of Cr (536.14 mg/kg) and Ni (257.8 mg/kg) among the selected heavy metals in sediment was above the PEC value, indicating that they have negative impacts on the ecosystem. According to the local background values, those obtained from the C-f, C-d, I-geo, SEF, PLI, PERI, etc., indexes demonstrated that heavy metal pollution in this region ranged from pollution-free to moderate pollution, with the largest contribution of Cr and Ni. Hence, they must be performed long-term dynamic monitoring of Ni and Cr to avoid ecological risks and protect the ecosystem's health. On the other hand, since the non-carcinogenic health risk (HI) of selected heavy metals in adults is less than 1, it has been determined that there is no health risk, while the HI value is greater than 3 in children. Accordingly, it indicates a very high health risk for children. This study also presents that cancer risk for heavy metals was higher than the acceptable limit (1 x 10(-6)) for adults and children. The results of this study have important guiding significance for selecting evaluation methods for heavy metal pollution in sediments.