鄂西北稀土矿区粮食与蔬菜中重金属污染风险评价

Risk assessment of heavy metal pollution in grains and vegetables in rare earth mining areas in Northwestern Hubei

目的 调查鄂西北稀土矿区粮食作物与蔬菜中重金属污染情况及其健康风险。方法 对当地居民日常食用、本地种植的6种粮食及20种蔬菜进行采样,用微波消解-电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)对样本中具有代表性的重金属铬(Cr)、铅(Pb)、汞(Hg)、镉(Cd)及类金属砷(As)的含量进行了测定,选用靶标危害系数法、内梅罗污染指数法、单因子污染指数法综合评价了不同作物的重金属污染风险。结果 研究区粮食中大米、小麦、花生以及蔬菜中菠菜、苋菜、红薯叶等叶菜类蔬菜及茄子、小葱均受到了不同程度的重金属污染。其中粮食作物的重金属污染多为单一Cr污染,蔬菜的污染类型多为复合型重金属污染。结论 健康风险评价表明食用该地区种植的大米、苋菜、红薯叶对健康产生影响的可能性极大;食用该地区种植的小麦、油麦菜、菠菜产生重金属危害的可能性较大;过量食用当地种植的花生、茄子、小葱也存在一定的风险。

Objective To investigate the heavy metal pollution and health risks in grain crops and vegetables in rare earth mining areas in Northwestern Hubei. Methods Samples were collected from 6 kinds of food crops and 20 kinds of vegetables that local residents eat and grow locally. The content of representative heavy metals chromium(Cr), lead(Pb), mercury(Hg), cadmium(Cd) and metalloid arsenic(As) in the samples was determined by microwave digestion-inductively coupled plasma mass spectrometry(ICP-MS), the pollution risks of heavy metals in different crops were comprehensively evaluated by target hazard coefficient method, Nemero pollution index method and single factor pollution index method. Results Rice, wheat, peanut, spinach, amaranth, sweet potato leaves and other leafy vegetables, eggplant and shallot in the food crops in the study area had been polluted by heavy metals to varying degrees. Most of the heavy metal pollution of food crops was single Cr pollution, and most of the pollution types of vegetables were compound heavy metal pollution. Conclusion The health risk assessment shows that eating rice, amaranth and sweet potato leaves planted in this area is very likely to have an impact on health;it is more likely that eating wheat, lettuce and spinach planted in this area will cause heavy metal harm;excessive consumption of locally grown peanuts, eggplant and shallots also has certain risks.