湘西花垣矿区蔬菜重金属污染现状及健康风险评价

Heavy Metals Concentrations and Health Risk in Vegetables Grown on Mn and Pb/Zn Mineland in Huayuan County,West Hunan Province,China

对湘西花垣锰矿、铅锌矿区的部分蔬菜及其种植土壤进行了调查和重金属含量分析,通过污染指数法和经蔬菜途径重金属暴露接触对人体的健康风险进行了系统评价。结果表明,与非矿区比较,两矿区蔬菜、土壤Pb、Zn和Cd含量较高,矿区土壤Pb、Zn、Cd含量均超过GB15618—1995《土壤环境质量标准》二级标准(pH<6.5)的污染警戒值;矿区蔬菜Pb、Zn和Cd含量均超过国家蔬菜重金属元素限量标准,分别为限量标准的2.0～10.75、0.9～2.5倍和2.2～19.8倍;两矿区蔬菜受到了Pb、Cd的严重污染,Zn的轻-中度污染。重金属暴露接触对人体的风险评估结果表明,两矿区居民通过蔬菜途径摄入的Pb和Cd对其健康存在较大的潜在风险,且对儿童的健康风险高于成年人。因此,矿区土壤上种植蔬菜会对食用这些蔬菜的当地居民产生一定的健康风险,应采取合适的治理措施进行矿区污染土壤的修复。

A systematic survey and determination of Mn,Pb,Zn,Cu and Cd concentrations in vegetables and the corresponding soils were conducted in Mn and Pb/Zn mines in Huayuan county,west Hunan.The possible health risk to local inhabitants via consumption of vegetables was assessed based on target hazard quotients（THQ） and pollution index.The results showed that Pb,Zn and Cd concentrations in vegetables and soils from Mn and Pb/Zn minelands were higher than those from non-mine land.Pb,Zn and Cd concentrations in the minesoils exceeded the threshold levels of China Environmental Quality Standard for Soils（GB 15618—1995 ClassⅡ）.Pb,Zn and Cd levels of the vegetables grown on minelands were 2.0~10.7 times,0.9~2.5 times and 2.2~19.8 times as high as the corresponding values for safe food（GB 14935—1994,GB 13106—1991 and GB 15201—1994） respectively.Vegetables grown on the Mn and Pb/Zn minelands were heavily polluted by Pb and Cd and slightly or moderately polluted by Zn.THQ of Pb and Cd in vegetables for both adults and children were greater than 1 indicating that the local inhabitants experience a high potential health risks by intake of Pb or Cd via consumption of these vegetables,especially for children.Therefore,some precaution measures should be taken to restore the contaminated minelands before they are recommended for growing vegetables.