有色冶金区土壤-蔬菜系统重金属污染特征及健康风险分析

采用对应采样方法研究大冶有色冶炼厂周围地区土壤、蔬菜中Cd、Cu、Pb和As的含量,并对蔬菜重金属污染状况、富集能力及健康风险进行了分析。结果表明,研究区土壤重金属污染严重,Cd、Cu、Pb和As平均含量分别达5.28、193.37、93.83和36.56 mg/kg,分别为湖北省对应元素土壤背景值的31.06、6.30、3.51和2.97倍,表现为以Cd为主的多种重金属共同污染。与《食品中污染物限量》(GB2762-2012)标准比较,蔬菜中Cd和Cu含量的样本超标率分别为68%和6%,而As、Pb的含量均不超标。蔬菜中重金属富集能力的排序为:CdCuAsPb,叶菜类蔬菜对Cd、Cu、Pb和As的富集系数均高于非叶菜类蔬菜。土壤和蔬菜重金属综合质量指数达10.07,为重度污染。研究区人群通过蔬菜摄入As、Cd的目标危险系数均大于1,存在As、Cd暴露的健康风险;成人和儿童食用蔬菜而摄入重金属的TTHQ分别为2.11~5.06和2.78~6.64,儿童比成人遭受的健康风险更大,并且距离冶炼厂越近,所遭受的健康风险越大。蔬菜中重金属的复合污染已使大冶有色冶炼厂周围居民面临潜在的健康风险。

CONTAMINATION AND HEALTH RISK FOR HEAVY METALS VIA CONSUMPTION OF VEGETABLES GROWN IN NON-FERROUS METALS SMELTING AREA

A systematic survey on concentrations of Cd,Cu,Pb and As in eight kinds of vegetables and their corresponding soils at 10 sampling sites near the Daye Copper Plant in Daye City,Hubei Province,China,was carried out for assessing heavy metal pollution,bio-concentration ability and potential health risk to local inhabitants due to exposure via consumption of vegetables.The results showed that the soils of the studied vegetable plots were seriously contaminated by heavy metals and the mean concentrations ofCd,Cu,Pb and As reached 5.28 mg/kg,193.37 mg/kg,93.83 mg/kg and 36.56 mg/kg,and are 31.06,6.30,3.51 and 2.97 times of background contents of the corresponding heavy metals in the soils of Hubei Province,respectively.The pollution characteristics of multi-metals in soils are mainly reflected by Cd.The proportions of vegetable samples which Cd and Cu concentrations exceeded the Maximum Levels of Contaminants in Foods (GB2762-2012) were 68％ and 6％,respectively.The values of bio-concentration factor from soil to edible part of vegetable decreased in the order of Cd ＞ Cu ＞ As ＞ Pb,and the bio-concentration factor values of all heavy metals in the edible part of leafy vegetables were higher than the non-leafy vegetables.The soils and vegetables were heavily polluted by heavy metals,as shown by the influence index of comprehensive quality of soils and vegetables is 10.07.The consumption of the polluted vegetables would lead to potential health risk especially for children,since both THQ values of Cd and As via the consumption of polluted vegetables were above 1.The total metals THQs for adults and children were 2.11-5.06,2.78-6.64,respectively,due to consumption of vegetable around the plant.The potential health risk for local residents living nearby Daye Copper Plant is serious due to the combined heavy metal in vegetables.