Source identification and risk assessment of potentially toxic elements in surface soil of townships in the northwest Hebei region

Soil environmental quality in townships is related to the development of rural revitalization and the smooth flow of urban-rural integration and development. However, the quality of soil environment in townships may be exposed to potential risks of potentially toxic elements pollution due to the influence of production and life. Thus, this study is based on descriptive statistical analysis, source identification, and systematic assessment of ecological and human health risks. The results showed that the mean content of eight potentially toxic elements in the study area was lower than the background value of the soil environment in Hebei Province only for the elements As, Pb, Zn and Hg, and the exceeding rate of Cr, Cu, Cd and Ni was higher than 55%. APCS-MLR model identified five categories of pollution sources with the following sources and contributions: industrial sources (47.1%), transportation sources (24.3%), natural sources (13.8%), agricultural sources (3.8%), and atmospheric deposition sources (11.0%). Ecological risks are mainly attributed to Cd and Hg, with high-risk areas concentrated in the central part of the study area. Probabilistic health risks indicate that adult and pediatric THI values are within the safe range at the 95% confidence interval and that children have some significant carcinogenic risk. Source contribution to health risk indicates that industrial and transportation sources are important sources of control for cancer risk, yet elemental As are less enriched, so there is no need to pay much attention to the impact of natural sources on health risk. In conclusion, this study provides a reference for risk prevention and potential source identification of potentially toxic elements in the top soil of the township.