我国36个重点城市饮用水中多环芳烃健康风险评价

Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in Drinking Waters of 36 Major Cities in China

分别用2种基于不确定性的风险评价方法(蒙特卡洛法和三角模糊数法)和1种基于确定性的风险评价方法(美国EPA终身致癌风险)对我国36个重点城市饮用水中多环芳烃的终生致癌风险进行评价。所研究的98个水厂出水中多环芳烃浓度范围为17.5~408.3 ng·L-1,致癌性多环芳烃(苯并[a]蒽,屈,苯并[b]荧蒽,苯并[k]荧蒽,苯并[a]芘,茚并[1,2,3-cd]芘)的总量浓度为nd^94.7 ng·L-1。所有水厂出水中苯并[a]芘浓度均小于10 ng·L-1。假设出厂水即为最终饮用水,对16种PAHs浓度用毒性当量因子法转化为相对于苯并[a]芘等效浓度(TEQ BaP)。使用概率风险评价方法计算,结果显示在95%的概率区间我国居民通过饮水途径暴露多环芳烃的终生致癌风险小于5.45×10-6(蒙特卡洛法)和7.56×10-6(三角模糊数法)。而采用确定性风险评价方法,计算得到的最大风险为7.12×10-6。两种计算方法得到的我国饮用水中多环芳烃的终生致癌风险都处于可接受水平。比较不同的评价方法后发现,不同方法获得的信息并不完全重合,相对于通常的基于确定性的非概率健康风险评价方法,基于不确定性的概率风险评价方法获得的结果更为保守。

Two kinds of probability risk assessment methods （Monte Carlo Analysis ＆ triangular fuzzy） and a non-probability risk assessment method （incremental lifetime cancer risk, ILCR）were used to assess the health risk of polycyclic aromatic hydrocarbons （PAHs） of finished water. The concentrations of total PAHs in fm- ished water of 98 waterworks in 36 major cities of china were in the range of 17.5 - 408.3 ng· L-1, and the total concentration of carcinogenicity PAHs （benzo [a]anthracene, chrysene, benzo [b]fluoranthene, benzo [k]fluoran- thene, benzo[a]pyrene, indeno[l,2,3-cd]pyrene） ranged from nd to 94.7 ng ·L-1. The concentrations of Benzo[a] pyrene in all waterworks were below 10 ng＂ L＂~. In the assessment approach, the finished water was considered as potable water. The concentrations of PAHs were expressed as the equivalent concentration of benzo[a]py-rene by toxic equivalency factors （TEFs）. The results suggested that incremental lifetime cancer risk based on MCA was below 5.45 x 10.6 and the ILCR based on tri-angular fuzzy number was 7.56 x 10＂6 at 95% interval, re- spectively. The maximum of ILCR derived from non-probability method was 7.12 x 106. Therefore, the ILCR of PAHs from both probability and non-probability risk assessment approaches could reach the same conclusion that ILCR for Chinese people were in an acceptable level. In general, different assessment methods may con- tain different information, and PRA method was more conservative than the point estimating method.