Human health risk assessment of soil in an abandoned arsenic plant site: implications for contaminated site remediation

The abandoned contaminated site remediation has been recognized valuable for their redevelopment bringing social, economic and environmental benefits. The risk assessment is a key step in the process of contaminate site remediation. However, in terms of experience of contaminated site risk assessment, China is in the early stage. A challenge for decision makers responsible for clean-up of contaminated sites has been the understanding the crucial role of risk assessment in the process of contaminated site remediation. In this study, a site-specific human health risk assessment was used to prioritize the high-risk sites contaminated with heavy metals (As, Cd, Hg, Pb, and Zn) in Luoma site, located in Hechi City, China. It is found that, for As, Cd, Pb and Zn, the China's soil threshold value exceeded in 96%, 78%, 35%, and 43% of analyzed soil samples, respectively. Further studies conclusively showed the soil at Luoma site in its present condition pose non-cancer and cancer risks to potential future receptors. The main contribution of non-cancer and cancer risks was through oral intake. As and Pb were the dominant substances responsible for cumulative risk and sub-areas which require to remediate. The obtained results have confirmed the environment effects and high human health risk at Luoma site. They may also be used to provide scientific basis for contaminated remediation and redevelopment.