Groundwater health risk assessment of North China Plain based on Monte Carlo model sensitivity analysis and morphological analysis: A case study of Shijiazhuang City.

The rapid development of the social economy and the influence of human activities can lead to aggravated groundwater pollution. Groundwater safety is the premise of residents' health. Therefore, studying the sustainable utilization and health risks of groundwater quality is important. The groundwater quality and potential health risks were evaluated in the Shijiazhuang area, which is located in the North China Plain in this paper. Based on 159 groundwater samples collected in the study area, the potential health risks of As, Cr⁶⁺, Ni, Pb, F^-, and NO₃ ^- to humans were evaluated from oral and skin contact. Results of the human health risk assessment showed that the average carcinogenic risk and non-carcinogenic risk of children are higher than those of adults. According to the spatial distribution of the total risk value, adults and children in the southwest of the study area face higher risks. Because of the uncertainty of USEPA, Monte Carlo simulation was used to calculate the probability of health risk assessment and prioritization of contaminant treatment. The results of the Monte Carlo simulation showed that the acceptable range for children is 6.82%, and the acceptable range for adults is 18.07%. According to the HRWM model, carcinogenic pollutants mainly include As, Cr⁶⁺, and Ni. The most important chemical species of As is HAsO₄ ^2-, followed by H₂AsO₄ ^-. Similarly, CrO₄ ^2- and Ni²⁺ are the main forms of Cr⁶⁺ and Ni. The results of this study can provide data support for the protection and management of groundwater quality in the North China Plain. PRACTITIONER POINTS: Children are more susceptible to carcinogenic risk than adults. After calculation, the main influencing elements are Ni and Cr. Metal morphology analysis was carried out, and the results showed that HAsO₄ ^2-, CrO₄ ^2-, and Ni²⁺ were the main types.