Objective In recent years, China has experienced several antimony (Sb) contamination incidents in aquatic environments, reflecting the severe status of waterborne Sb pollution. However, research on water quality criteria for the protection of human health against Sb remains insufficient in China, underscoring the urgent need for study to provide scientific evidence to support the rolling revision of relevant water quality standards.

Methods Based on the Technical Guideline for Deriving Water Quality Criteria for the Protection of Human Health (HJ 837-2017), the results of international research on criteria for human health protection against Sb, the workflow for deriving water quality criteria for human health protection, and health risk assessment method, a comprehensive assessment was conducted for Sb toxic effects and Sb exposure parameters for the Chinese population.

Results Using changes in body weight and water intake as the toxicity endpoints, the no-observed-adverse-effect level for Sb was determined to be 6 mg/(kg·d), with an uncertainty factor of 1 000 or 623, yielding a reference dose of 0.006 mg/(kg·d) or 0.009 6 mg/(kg·d). The relative source contribution was calculated using the traditional percentage method, exposure decision tree method, and China's multi-pathway and multi-medium exposure risk assessment method, yielding values of 43.8%, 20%, and 13.3%, respectively. The value recommended by the World Health Organization is 10%. Based on these parameters, the derived water quality criteria for protecting human health against Sb exposure via drinking water and aquatic food ingestion ranged from 19.1 to 134 μg/L (19.7-138 μg/L for drinking-water-only exposure). For the maximum protection of the population, this study prioritized the reference dose of 0.006 mg/(kg·d). To accurately reflect the exposure characteristics of the Chinese population, priority was given to the relative source contribution of 13.3% calculated using China's multi-pathway and multi-medium exposure risk assessment method based on China's actual conditions. Accordingly, the recommended ambient water quality criteria were 25.3 μg/L for Sb exposure via drinking water and consumption of aquatic products (26.1 μg/L for drinking-water-only exposure).

Conclusion This study derived the series and recommended water quality criteria for protection of human health against Sb in China, providing a reference for the rolling revision of standard limits for Sb in drinking water sources and drinking water in China, and enhancing the scientific rigor and precision of Sb pollution control and management in the country.