广西典型铝矿区复垦地蔬菜中重金属含量特征及健康风险评价

Heavy Metal Content Characteristics and Health Risk Assessment of Vegetables in Reclaimed Land of Bauxite Mine Region in Guangxi

【目的】探究铝土矿复垦区蔬菜重金属污染特征及其健康风险,为铝土矿复垦土壤的安全利用提供参考依据。【方法】测定广西百色市典型铝土矿复垦区种植蔬菜的铅(Pb)、镉(Cd)、铬(Cr)、砷(As)和汞(Hg)含量,采用单因子指数法和内梅罗综合污染指数法分析其重金属污染状况,并通过目标危害系数(THQ)法评价其健康风险。【结果】复垦地土壤中Cd含量(2.36 mg/kg)和As含量(119.27 mg/kg)超过GB 15618-2018《农用地土壤污染风险管控标准》风险筛选值;土壤重金属单项污染指数范围在0.45~7.87,排序为Cd>As>Cr>Pb>Hg,综合污染指数为5.89,属于重污染水平土壤。所调查主要种植的14种蔬菜中,茄子的Pb含量(0.1490 mg/kg)、Cd含量(0.0860 mg/kg)和生姜的Pb含量(0.2500 mg/kg)分别为GB 2762-2017《食品中污染物限量》中标准值的1.49、1.73和2.46倍,其余蔬菜的重金属含量未超标。相关分析结果显示,蔬菜中的重金属Pb和Cd含量与土壤中的Pb和Cd含量呈正相关。健康风险评价结果显示,成人的单一重金属健康风险和重金属复合健康风险指数均小于1.0000,表明成人食用该复垦区种植的蔬菜不存在健康风险;除鱼腥草、小白菜和卷心白菜的重金属复合风险大于1.0000外,儿童的其余单一重金属健康风险均小于1.0000,表明儿童食用鱼腥草、小白菜和卷心白菜存在健康风险。【结论】广西典型铝土矿复垦区土壤中重金属处于重度污染水平,且以Cd和As为主要污染因子;儿童食用鱼腥草、小白菜和卷心白菜存在健康风险。

【Objective】In order to provide a reference for the safe use of reclaimed soil in bauxite,studying the characteristics of heavy metal pollution in vegetables grown in reclaimed area and evaluating the risk of human health were conducted.【Method】The contents of lead,cadmium,chromium,arsenic and mercury in vegetables grown in the typical bauxite in Baise of Guangxi were analyzed.The single factor index and Nemerow composite pollution index were used to analyze the pollution status of heavy metal.Target hazard quotient(THQ)was used to evaluate the human health risks.【Result】The content of cadmium(2.36 mg/kg)and arsenic(119.27 mg/kg)in reclaimed soil exceeded the risk screening value of GB 15168-2018 Risk Control Standard for Soil Contamination of Agricultural Land;The single factor pollution index of heavy metals in soil ranged from 0.45 to 7.87,and the sequencing was cadmium>arsenic>chromium>lead>mercury,the composite pollution index was 5.89,which belonged to heavy pollution.Among the 14 kinds of vegetables investigated,compared with the GB 2762-2017 Maximum Levels of Contaminants in Foods,the content of lead(0.1490 mg/kg)and cadmium(0.0865 mg/kg)in egg plant were 1.49 times and 1.73 times of the standard value,respectively,the content of lead(0.2500 mg/kg)in ginger was 2.46 times of the standard value,and heavy metal content in other vegetables did not exceed it.The results of correlation analysis showed that the content of Pb and Cd in vegetables was positively correlated with the content of Pb and Cd in soil.The result of health risk assessment showed that the human health risk of single heavy metal and multiple heavy metal for adults were all less than 1.0000,indicating that there was no health risk for adults to intake vegetables grown in the reclaimed area;Expect the multiple heavy metals compound risk of Houttuynia cordata Thunb,Brassica chinensis L.and B.rapa pekinensis was greater than 1.0000,the heavy metal health risk for children were all less than 1,indicating that eating H.cordata Thunb,B.chinensis L.and B.rapa pekinensis had health risk to children.【Conclusion】The heavy metals in the reclaimed soil after of the typical bauxite in Baise of Guangxi are at heavy pollution level,and Cd and As are the main pollution factors.Heavy metals ingested through Houttuyniacordata Thunb,B.chinensis L.and B.arapapekinensis have human health risks to children.