Spatial Probability Health Risk Assessment of Drinking Water Sources in Zhongjiang County based on Sequential Indicator Simulation

In order to analyze the health risk level of water sources in Zhongjiang County, water quality monitoring data of drinking water sources in 60 towns in the study area were collected. The health risk evaluation model recommended by the USEPA was used to evaluate 13 water quality indexes. The sequential indicator simulation method （SIS） was adopted to analyze the spatial uncertainty of health risk of the water sources. The results showed that the non-carcinogenic risk of water source for adults and children and the carcinogenic risk of children were small, and there is a certain carcinogenic risk for adults. The cumulative contribution of F^-、As、NO₃^-、and Pb to the total non-carcinogenic risk exceeded 90%, and the cumulative contribution of Cr⁶⁺ and As to the total carcinogenic risk exceeded 95%. Adult carcinogenic risk probability greater than 75 % of the area was 140.54km², accounting for 6.4% of the total area of Zhongjiang County, adult carcinogenic risk probability ranging from 25% to 75% of the area is 333.28km², accounting for about 15.2% of the total area. According to the adult carcinogenic risk probability and its standard deviation, the water source area of Zhongjiang County is divided into threelevel control areas, namely priority, key, and general. The zoning risk control suggestions were put forward. In this study, SIS method was introduced to analyze the spatial uncertainty of health risk, which could provide more intuitive and accurate basis for water source risk management for management decision-makers.