Objective To assess the health risk in urban water supply and illustrate the condition of basic water quality according to monitoring data of source water and finished water in Minhang district of Shanghai.
Methods According to the monitoring data of source water and finished water of the waterworks in Minhang District of Shanghai in 2009, health risk assessment was made with the environment-health risk assessment model.
Results The person-year risk for chemical carcinogenetic substances with genetic toxicity in drinking water ranked from high risk to low risk as:chromium (Cr6+), arsenic (As)and cadmium (Cd). The risk casued by Cr6+ and As accounted for 98.33% of total risk of the carcinogenic substances. The total risk of the three carcinogenetic substances was higher than the maximal acceptable risk value recommended by World Health Organization (WHO)and Environment Protection Agency (EPA)and was lower than the maximal acceptable value of International Commission on Radiological Protection (ICRP). The person-year risk for chemicals with non-genetic toxicity ranked from high to low as F > Cu > Pb > (NO3-, NH3-N, Fe, Mn, Hg) > Zn > CN-1 > Se > Volatile phenol. The risk caused by F, Cu and Pb accounted for 78% of total risk for chemicals with nongenetic toxicity. The total risk for non-genetic toxic substances was far lower than the acceptable risk value recommended by WHO, EPA, and ICRP and was at a relative safe level. The health risk caused by genetic toxic substances accounted for a considerable proportion (99%)in total health risk.
Conclusion The health risk of urban water supply in Minhang District of Shanghai is mainly caused by carcinogenetic substances with genetic toxicity such as Cr6+ and As, which should be controlled in high priority.
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