高砷煤矿污染土壤的小麦砷累积研究

Arsenic Accumulation in Wheat Grown in the Field Polluted by Arsenic Coal Mine

为了解砷污染土壤对小麦品质的影响及食用砷污染土壤种植的小麦对人群健康的影响,以贵州省兴仁县交乐高砷煤矿区砷污染农田的土壤-小麦系统为研究对象,采用氢化物发生-原子荧光光度法测定土壤和小麦砷含量,并对砷污染土壤及小麦中砷分布特征进行研究。结果表明,受污染农田土壤(区域Ⅰ、区域Ⅱ)的砷含量显著高于周边未受污染农田(区域Ⅲ),区域Ⅰ土壤pH值最低(4.57),土壤砷含量分别是区域Ⅱ、区域Ⅲ的1.94和2.13倍,土壤砷含量与土壤pH值呈显著负相关关系;区域Ⅰ小麦样品不同器官的砷含量为1.37mg·kg^(-1)(根)、0.74mg·kg^(-1)(茎叶)、0.85mg·kg^(-1)(籽粒);受试样品中,67%的小麦籽粒砷含量高于GB2762-2012中规定的小麦砷含量限值(0.5mg·kg^(-1))。采用USEPA推荐健康风险评价模型对当地居民以小麦为砷摄入途径的健康风险评价结果显示,区域Ⅰ、区域Ⅱ小麦的HQ值分别为2.82和1.19,区域Ⅲ为0.97。受试土壤砷污染已对小麦品质产生影响,食用矿区附近砷污染农田种植的小麦可能对居民健康有影响。

In order to study the influence of arsenic-contaminated soil to wheat quality and the human health,the content and distribution characteristics of arsenic in soil-wheat system were studied in the field polluted by the drainage of high arsenic coal mine located in Xingren county,Guizhou province of China.The arsenic contents in soil and wheat samples were determined by hydride generation-atomic fluorescence and distribution characteristics of arsenic in soil-wheat system were analyzed.It was found that soil arsenic content in polluted field（areaⅠ and areaⅡ）was significantly higher than the control area（areaⅢ）.In area I,the pH value of soilⅠ was 4.57,and the soil arsenic content was 1.94 and 2.13 times higher than those in area II and areaⅢ.Soil arsenic content had a significantly negative correlation with soil pH.Arsenic contents of 67% wheat grain samples exceeded wheat arsenic limit value（0.5 mg·kg^-1）in GB2762-2012.Arsenic contents in different organs of wheat were 1.37 mg·kg^-1 in root,0.74 mg·kg^-1 in leaf,and 0.85 mg·kg^-1 in grain.The potential health risk forlocal residents through consuming the wheat was evaluated by using the USEPA recommended health risk assessment model.The Hazard Quotient（HQ）values for the wheat were 2.82 in area I and 1.19 in areaⅡ,while it was lower than 1.0 in areaⅢ.It was indicated that high arsenic background value in soil had influenced the wheat quality slightly,and consumption of the wheat planted in the polluted area had more serious threat on human health.