东平湖湖水汞砷形态赋存特征及健康风险评价

了解东平湖湖水中汞(Hg)和砷(As)的形态赋存特征及健康风险。方法于2016年5月,在东平湖采集30个表层水样,采用原子荧光光度法对Hg和As的总浓度及其不同形态浓度进行测定,并采用美国国家环保署(US EPA)推荐的健康风险评价模型对其通过饮水途径产生的健康风险进行了评价。结果东平湖湖水中总As浓度为(7.289±0.832)μg/L,总Hg浓度的中位数为0.929(0.063~3.230)μg/L;总As浓度均符合国家Ⅲ类水标准,而总Hg的超标率为96.7%。溶解态Hg浓度占总Hg的平均比例为63.4%,高于颗粒态Hg浓度占总Hg的比例(36.6%)。各采样点溶解态As和颗粒态As占总As比例的平均值分别为53.4%和46.6%,湖区北部采样点溶解态As所占比重较大;溶解态As中致毒性较大的As(Ⅲ)比例较小。As和Hg通过饮水途径产生的健康风险值分别为5.46×10~(-5)/a和1.56×10~(-9)/a,As的健康风险值远高于Hg,且超过最大可接受水平(5×10~(-5)/a)。结论东平湖湖水中Hg浓度超标,As通过饮水途径产生的健康风险值超过最大可接受风险水平,Hg和As应作为东平湖的重点监控因子。

Speciation distribution characteristics and health risk assessment of arsenic and mercury concentrations in water of Dongping Lake

Objective To understand the total and speciation concentrations of arsenic (As) and mercury (Hg) and their distribution characteristics and health risk in Dongping Lake.Methods The surface water samples from 30 sampling points of Dongping Lake were collected in May 2016 and the total and speciation concentrations of As and Hg were analyzed by using atomic fluorescence spectrometry (AFS).Health risk of As and Hg through drinking the water of Dongping Lake was assessed by using the models of US EPA.Results The average concentrations of As was (7.289±0.832) μg/L and the median of Hg was 0.929(0.063-3.230) μg/L in the water of Dongping Lake.Arsenic concentrations were lower than the limit value (50 μg/L) of the class Ⅲ standard of national environmental quality for surface water (GB 3838-2002),but mercury concentrations in 96.7％ of the samples exceeded the standard value (0.1 μg/L).The average proportion of dissolved mercury concentrations was 63.4％,which was higher than that of the particulate mercury concentrations in total mercury concentrations (36.6％).The average proportions of dissolved and particulate arsenic concentrations in total arsenic concentrations were 53.4％ and 46.6％,respectively.Dissolved arsenic concentrations generally accounted for higher proportions than particulate arsenic concentrations in the north part of the lake.As (Ⅲ) with the highest toxicity accounts for lowest ratio.The values of the health risk of As and Hg were 5.46×10-5 per year and 1.56×10-9 per year,respectively.The health risk of As was much higher than Hg,and exceeded the maximum acceptable risk level (5×10-5 per year) recommended by International Commission on Radiological Protection (ICRP).Conclusion The concentrations of Hg in the water of Dongping Lake exceeded the standard value and the health risk of As through drinking the water exceeded the maximum acceptable risk level.Therefore,Hg and As should be taken as the important monitoring factors in Dongping Lake.