土壤-黎药系统中重金属的迁移富集特征及健康风险评价

Characteristics of Migration and Accumulation of Heavy Metals in Soil-Li Medicine System and Health Risk Evaluation

采用地累积指数法、富集系数法、迁移系数法和靶标危害系数法对土壤-黎药系统中重金属元素铜(Cu)、铬(Cr)、铅(Pb)和镉(Cd)的含量及迁移富集特征进行测评。结果表明:除天然林地土壤未受到Cd污染外,蔬菜地、天然林地、橡胶林地和植物园地4种黎药样地均受到Cr、Cu和Cd不同程度的污染;除了以根部入药的五指毛桃和以叶入药的草豆蔻受到Pb的轻微污染外,大沙叶、益智、豆蔻和砂仁4种黎药的药用部位均未受到重金属污染;6种黎药对Cd和Cu的富集能力较强,对Cr的富集能力较弱,对Pb的富集能力最弱;Cd和Pb在黎药茎—叶间的迁移能力极强,Cr在茎—叶间的迁移能力较强,Cu在根—茎—叶间的迁移能力一般;6种黎药药用部位残留的Cd、Cr、Cu和Pb对暴露人群无摄入风险。

In this research, a series of methods based on geo-accumulation index, bio-concentration factors, trans-location factor, and target hazard quotients were utilized to analyze and evaluate the heavy metal contents including Cu, Cr, Pb,Cd, as well as the characteristics of translocated accumulation from soil-Li medicine system. The results showed that the natural forests were free from Cd pollution, whereas soils of vegetable field, botanical garden, rubber plantation of Li medicine samples were all polluted by Cr, Cu, and Cd with various degrees. In addition to the fact that Fructus Amomi Longiligularis with its roots used as medicine and Alpiniae Katsumadai Semen with its leaves used as medicine were slightly polluted by Pb, medical part of the stem and leaf of Hongkong Pavetta, Sharpleaf Galangal Fruit, Whitefruit Amomim Fruit, Fructus Amomi Longiligularis were all free from heavy metal pollution. The enrichment capacity of 6 kinds of Li medicines on heavy metals was different, which was stronger for Cd and Cu, weak for Cr, and weakest for Pb. The heavy metals Cd and Pb presented extremely strong ability to translocate between stem and leaf of Li medicine, while Cr presented strong ability to translocate between stem and leaf, and Cu presented relatively moderate translocation ability from root to stem to leaf. The residual Cd, Cr, Cu, Pb in medical parts of six kinds of Li medicine did not pose an edible risk to the exposed population.