Arsenic Contamination Levels in Drinking Water and Health Risk Assessment in a Certain Area of Shaanxi Province

Abstract

Objective: To analyze the quality status and major risk indicators of drinking water in a certain area of Shaanxi Province, China, from 2023 to 2025, to explore factors associated with arsenic exceedance, and to assess the health risks of arsenic exposure through drinking water. Methods: A total of 137 drinking water samples collected from 2023 to 2025 were included. Water quality was evaluated according to the Standards for Drinking Water Quality (GB 5749–2022). Chi-square test and logistic regression were used to analyze factors associated with arsenic exceedance. Based on the health risk assessment model recommended by the US Environmental Protection Agency (US EPA), non-carcinogenic and carcinogenic risks of arsenic exposure through drinking water were estimated for different population groups. Results: The overall compliance rate of drinking water quality was 77.37% during 2023–2025. The main indicators exceeding the standard were arsenic, total bacterial count, and manganese. Among them, arsenic was the predominant risk indicator, with 29 samples exceeding the standard and an exceedance rate of 21.17%. Significant differences were observed in arsenic exceedance rates among different years (P<0.05), but no significant linear trend was found. Multivariable logistic regression showed that, compared with urban centralized water supply, rural centralized water supply and decentralized water supply were associated with higher risks of arsenic exceedance, with the risk being more pronounced in decentralized water supply. Year was also associated with arsenic exceedance, whereas no significant association was found for hydrological period. Health risk assessment indicated that under the general exposure scenario, the hazard quotient (HQ) was >1 for children aged 0-5 years; under the high-exposure scenario, HQ was >1 for all population groups. In addition, the carcinogenic risk exceeded 10-4 in all groups. Conclusions: The quality of drinking water in this area still requires improvement. Arsenic was identified as the primary risk indicator. Rural centralized water supply and decentralized water supply were the key risk settings, and children, especially those aged 0-5 years, should be regarded as the priority population for protection. Strengthened monitoring, source tracing, and health risk management for arsenic contamination are warranted.