Implementation of an integrated health risk assessment coupled with spatial interpolation and source contribution: a case study of soil heavy metals from an abandoned industrial area in Suzhou, China

Soil heavy metal contaminated sites with multiple sources of pollution have caused worldwide public concern. However, the lack of correlation of risk assessment between source identification of heavy metal leads to unclear direction of source governance. An integrated methodology is established in this study by combining source apportionment and human health risks model to characterize source-identified risks of heavy metals based on spatial interplotation. Principal component analysis and positive matrix factorization model are used to identify and classify potential sources of heavy metals synthetically. The integrated results are incorporated into the health risk model to evaluate potential non-carcinogenic and carcinogenic risk of soil heavy metals. A case study was conducted in Suzhou city of China. The results indicate that concentrations of Cd and Hg were highly above the background values, accounting for percentages of 239.6% and 415.9% above background values, respectively. The source-contributed human health risk index of As contributed 76.9% to non-carcinogenic risk by pollutant sources of agriculture activities. The non-carcinogenic health risk index for adults and children are 0.308 and 1.00 respectively, indicating health threat to the children. Overall, the non-carcinogenic and carcinogenic risks of heavy metals are at an unacceptable level of risk and require environmental management. Furthermore, the health risk evaluation based on source contribution suggests that industrial processes contribute more to the health risk of heavy metals in soils. This study will provide a new insight for the treatment of mutil-sources of soil heavy metal pollution and also some reference value for the improvement of the risk assessment system.