吉林西部地区高砷地下水砷的阈值分析及风险评价

Threshold Analysis and Health Risk Assessment of Arsenic in Groundwater in Western Jilin Province

高砷地下水导致的砷中毒是吉林西部地区近年来新发现的地方病。为评价饮用水中砷对人体健康产生的潜在危害,在野外调查、采样分析的基础上,开展了水砷安全阈值分析,确定了砷的总质量浓度0.05mg/L为研究区的水砷安全阈值,建立了地下水健康风险评价模型,进行了地下水砷健康风险评价。结果表明:研究区地下水砷引起的个人年均风险度最高达2.11×10-3 a-1,其中高砷的第四系承压水中97.06%的采样点水砷对人体的个人年均致癌风险度,大于国际辐射防护委员会(ICRP)推荐的最大可接受值5.0×10-5 a-1;作为备用水源的第三系大安组、泰康组承压水69.57%采样点砷的致癌风险度也超过最大可接受风险水平。通过对风险度评价结果与砷中毒病情等资料的对比分析,风险评价结果与砷中毒病情基本一致,验证了评价结果的合理性。

Arsenism is a new endemic disease resulted from drinking the high arsenic groundwater. In order to evaluate the potential health hazards of arsenic in drinking water, field investigations and sample analysis have been finished, the safety threshold of arsenic in groundwater have been discussed. By analysis of threshold, total arsenic content in water less than 0.05 mg/L was determined as the safe threshold of water arsenic in study area. An evaluation model about the risk of groundwater has been set up, and health risk assessment has been carried out. In all samples, the maximum value of individual annual health risks was 2.11 ）〈 10_3 a-1 , and health risk of arsenic in 97.06% sampling sites of confined water of Quaternary period were greater than 5.0 X 10.5 a-1 , acceptable maximum value recommended by ICRP. Confined water of Tertiary is the backup water source, health risk of arsenic in 69.57% of its sampling sites exceeded the acceptable maximum value. Comparison analysis of the risk assessment results and the illness condition show that the results of health risk assessment are similar to arsenism information, which prove the evaluation results are all reasonable.