农村集中式供水中4种金属元素暴露水平及风险评价

Exposure Level and Risk Assessment of Metal Elements in Rural Central Drinking Water Supplies in Guangdong Province

目的 评价广东省农村饮用水中重金属暴露水平及对人体健康产生的潜在威胁。方法 于2012年7—9月对全省18个地级市的涉农县(区)集中式供水中重金属镉、铬(六价)、铅、汞含量进行测定,每个集中式供水监测点共监测2份水样(出厂水和末梢水各1份),按照美国环保局环境污染健康风险评价模型对4种金属元素通过饮水途径所引起的健康风险进行评价。结果 广东农村集中式供水中镉、铬(六价)、铅、汞的暴露水平分别为0~5、0~50、0~13、0~13μg/L。镉、铬(六价)、汞、铅饮水途径平均个人年风险分别为1.37×10-6、9.20×10-6、1.50×10-10、8.02×10-10/年,有个别地级市4种金属元素的总风险超过国际辐射防护委员会(ICRP)推荐的最大可接受值。结论 致癌物镉、六价铬(六价)等是广东省农村集中式供水产生风险的主要污染物,应作为风险决策的重点对象。

Objectives To investigate the exposure level of 4 metal elements( Pb,Cd,Hg,Cr) in drinking water and its potential health risk for human security in Guangdong. Methods Two samples( treated water and tap water) from each of monitoring point in centralized water supplies were collected from 18 cities in July to September in 2012. The content of Pb,Cd,Hg and Cr+ 6in drinking water was monitored. A health risk assessment model recommended by US EPA was used for health risk assessment. Results The contents of Cd,Cr+ 6,Pb and Hg in rural central drinking water were 0 ~ 5 μg /L,0 ~ 50 μg /L,0 ~ 13 μg /L and 0 ~ 13 μg /L,respectively. The average health risk of Cd,Cr+ 6,Pb and Hg caused by drinking water for individual person per year were 1.37 ×10- 6,9. 20 × 10- 6,1. 50 × 10- 10and 8. 02 × 10- 10,respectively. The total risks associated with the 4 metal elements in some cities were higher than the maximum allowance levels recommended by ICRP( 5. 0 × 10- 5/y),greatly beyond the standard recommended by the Sweden Bureau of Environment Protection and the Holland Ministry of Building and Environment Protection. Conclusions Cd and Cr+ 6were the main pollutants for healthy risk in rural central drinking water. The carcinogenic properties of Cd and Cr should be taken as a key target for prevention strategies.