Abstract：Based on the health risk assessment theory of US NAS (U.S. National Research Council of National Academy of Science)’, a four-step of methodological framework of emergency health risk assessment of water pollution accidents that includes hazard identification, dose-response assessment, exposure assessment and risk characterization was developed. Considering the characteristics of short term, high dose exposure of the sudden water pollution accidents, the method specified for acute reference concentration was proposed, as well as quotient method and probability distribution of quotients were recommended for risk characterization and classification. The Songhua River nitrobenzene water pollution accident was used as an example for verifying the feasibility of the framework of emergency health risk assessment of sudden water pollution accident. Acute reference concentration of nitrobenzene to protect the health of adults and children was calculated by using present method and the value was 0.175and 0.05mg/L, respectively. Risk percentage of the nitrobenzene water accident was 29% and 62%, and the risk grade was middle and high, respectively. The results showed that acute health risk of water pollution accident can be characterized by this emergency health risk assessment. Finally, the difficulties in China carrying out emergency health risk assessment of water accident were discussed, and some suggestions were given.
