Which organic contaminants should be paid more attention: Based on an improved health risk assessment framework

The increasing chemical pollution of the drinking water is widely concerned. Large number of organic contaminants cannot be removed by conventional water treatment technology due to their low concentration, and long-term exposure may pose significant risks to human health. Which organic contaminants in drinking water should be given more attention has been a topic of great concern in recent years. To identify the organic contaminants that need attention, this research proposes an improved health risk screening method to quantitatively analyze the risks of accumulation, persistence, toxicity, and antibiotic resistance. Compared with conventional method, 26 compounds were added to the improved screening list, including 9 DBPs (e.g., NDMA), 3 antibiotics (e.g., oxytetracycline), PFNA and other compounds. Overall, antibiotics and plasticizers rose in the risk rankings. From the perspective of the proportion of total risk value, a single risk plays a decisive role (more than 99%) in the ranking. This change suggests that antibiotic resistance and the accumulation of organic matter are as important as their toxic risks to humans. 58 compounds were recommended for the priority control organic contaminants list in drinking water. This list provides the necessary information for authoritative regulations to monitor, control, assess, and manage the risks of environmentally relevant compounds in drinking water in China.