2015年重庆市农村集中式供水化学污染指标健康风险评价

目的 评估2015年重庆市农村集中式供水中化学污染物对人体健康存在的潜在危害,为风险管理提供科学依据。方法 选择22个区县,每个区县选择70%的乡镇,每个乡镇选择1~2个农村集中式供水监测点,于2015年丰水期采集出厂水水样,按照美国环保署健康风险评价模型对17项化学污染经饮水途径所致的健康风险进行评价。结果 重庆农村集中式供水出厂水年均健康总风险为1.59×10^-6(a^-1),非致癌健康风险占总风险比例不到1%,风险主要来源于水中化学致癌物铬、砷和三氯甲烷,占健康总风险的比例依次为48.5%、45.4%、5.2%;重庆市农村集中式供水出厂水健康风险在国际辐射防护委员会推荐的最大可接受风险水平范围5×10^-5(a^-1)内,但又略超过瑞典环境保护局规定的最大可接受风险水平1×10^-6(a^-1)。结论 重庆市农村集中式供水出厂水健康总风险超过了瑞典环保局推荐的可接受风险水平,需要引起重视。对于健康总风险超过1×10^-6(a^-1)的农村集中式供水,要继续加强对相应化学污染物的监测和控制。在重庆市农村集中式供水风险管理中,应优先控制的污染指标依次为铬、砷及三氯甲烷指标。

Health risk assessment of chemical pollution indicators in rural centralized water supply in Chongqing Municipality, 2015

Objective To evaluate the potential health risk of chemical pollutants in rural centralized water supply in Chongqing Municipality in 2015, and to provide a scientific basis for the risk management. Methods We firstly selected 22 districts or counties, secondly selected 70% of the townships in each district or county, and thirdly selected 1-2 rural centralized water supply monitoring points in each township. Factory water samples were collected in the wet season in 2015, and then the health risk of 17 kinds of chemical pollutants in drinking water was evaluated according to the health risk assessment model recommended by US EPA.Results The annual average total health risk of factory water in rural centralized water supply in Chongqing was 1.59×10^-6 (a^-1), and the non-carcinogenic health risk accounted for less than 1% of the total risk. The risk was mainly from the chemical carcinogens (including chromium, arsenic and chloroform) in water, with the proportion of total health risk being 48.5%, 45.4% and 5.2% respectively. The health risk of factory water in rural centralized water supply in Chongqing was lower than the maximum acceptable risk level (5×10^-5 (a^-1)) recommended by International Commission on Radiological Protection (ICRP), but slightly higher than the maximum acceptable risk level (1×10^-6 (a^-1)) recommended by the Swedish Environmental Protection Agency. Conclusions The total health risk of factory water in rural centralized water supply in Chongqing Municipality is slightly higher than the maximum acceptable risk level recommended by the Swedish Environmental Protection Agency; and hence, more attention should be paid to it. It is necessary to continuously strengthen the monitoring and control of the chemical pollutants in the rural centralized water supply with the health risk higher than 1×10^-6 (a^-1). In the risk management of rural centralized water supply in Chongqing Municipality, the pollution indicators that should be given priority to control are chromium, arsenic and chloroform.