贵州某典型汞矿区流域水稻中总汞和甲基汞含量及暴露风险  

Total Mercury and Methylmercury Concentrations and Risk Assessments in Rice Plants Collected from a River Watershed in a Typical Mercury Mining Area of Guizhou

作　　者：李瑞阳[1,2] 徐晓航[2,3] 许志东[2,3] 敖明[2,4] 商立海[2] 仇广乐[2] 汤顺林[1] 

机构地区：[1]河南理工大学资源与环境学院,河南焦作454000 [2]中国科学院地球化学研究所,环境地球化学国家重点实验室,贵州贵阳550081 [3]中国科学院大学,北京100049 [4]贵州大学资源与环境工程学院,贵州贵阳550025

出　　处：《环境科学研究》2016年第12期1829-1839,共11页Research of Environmental Sciences

基　　金：国家重点基础研究计划项目(2013CB430004);国家自然科学基金项目(41273152,41372360)

摘　　要：鉴于流域尺度内水稻植株不同组织中总汞和甲基汞含量及人群进食稻米的汞暴露风险研究较少,系统采集了贵州省铜仁市受万山废弃汞矿影响的瓦屋河流域内水稻植株及对应根际土壤样品,分析水稻植株不同组织中的w（总汞）、w（甲基汞）及其影响因素,以及流域内人群食用稻米的汞暴露风险.结果表明：瓦屋河流域水稻精米中w（总汞）平均值为（14.2±7.0）μg/kg（范围为4.1-34.0μg/kg,n=24）,精米中w（甲基汞）平均值为（7.229±3.957）μg/kg（范围为1.974-17.364μg/kg,n=24）.精米中w（总汞）与水稻茎、叶中w（总汞）均呈较显著正相关（R=0.531,P〈0.01;R=0.499,P〈0.05）,精米中w（甲基汞）与水稻根、茎中w（甲基汞）也均呈显著正相关（R=0.525,P〈0.01;R=0.612,P〈0.01）;w（总汞）、w（甲基汞）均与土壤理化参数存在一定正相关关系,并均与距污染源距离呈负相关.根据精米中w（甲基汞）平均值,并按照US EPA（美国国家环境保护局）推荐的甲基汞日暴露量（ID）和危害指数（HI）的评估方法计算的瓦屋河流域居民甲基汞日暴露量为（0.075±0.041）μg/（kg·d）,低于较为严厉的US EPA推荐的甲基汞日安全摄入量（Rf D）,危害指数为0.75.从平均状况来看,人体摄入该地区生产的精米相对较为安全.In view of the lack of knowledge of total mercury（ THg） and methylmercury（ Me Hg） in different tissues of rice plants and the risk of mercury exposure to rice at the river basin scale,rice plants and the rhizosphere soil in Wawu River Watershed flowing through the Tongren Wanshan abandoned mercury（ Hg） mining area in Guizhou Province were collected. The goal was to clearly understand concentrations of THg and Me Hg in different tissues of rice plants and Hg exposure risks via rice consumption. The results showed that mean concentration of THg in rice grain was（ 14. 2 ± 7. 0） μg/kg with range of 4. 1 to 34. 0 μg/kg（ n = 24）,and Me Hg in rice grain ranged from 1. 974 μg/kg to 17. 364 μg/kg with the mean value of（ 7. 229 ± 3. 957） μg/kg（ n = 24）. Grain THg was significantly positively correlated with stalk and leaf THg（ R = 0. 531,P〈0. 01; R = 0. 499,P〈0. 05）,and Me Hg was positively correlated with root and stalk Me Hg（ R = 0. 525,P〈0. 01; R = 0. 612,P〈0. 01）. A positive correlation between THg and Me Hg concentrations with soil parameters,and a significant negative correlation with distance from Hg contaminated sites,were observed. According to the mean value of Me Hg in rice grain and the calculation method of the ID and HI recommended by US EPA,Me Mg ID and HI values were（ 0. 075 ± 0. 041） μg/（ kg·d） and 0. 75,which were lower than the severe Rf D level recommended by US EPA. On average,it is still relatively safe for humans to eat rice produced by the region.

关 键 词：汞矿区 水稻 土壤 汞 甲基汞 风险评估 

分 类 号：X502[环境科学与工程—环境工程]