西双版纳州茶园土壤重金属污染特征及生态风险评价

Heavy Metal Pollution Characteristics and Ecological Risk Analysis for Soil in Tea Gardens of Xishuangbanna

研究西双版纳州茶园土壤重金属含量,并应用HKANSON潜在生态风险指数法对茶园土壤重金属潜在生态风险进行评价。结果表明,西双版纳州茶园土壤中各个重金属的平均含量与《茶叶产地环境技术条件》、《绿色食品产地环境质量》、《有机茶产地环境条件》、《无公害食品茶叶产地环境条件》、《土壤环境质量标准》二级标准相比均未超标;单因子潜在生态风险指数(Eir)平均值的大小顺序依次为:Hg(51.93)>Cd(43.55)>As(8.32)>Pb(5.15)>Ni(1.83)>Cr(1.23)>Cu(0.04),只有Hg,Cd存在中等水平潜在生态风险,其他重金属均属于轻微生态风险;7种重金属综合因子潜在生态风险指数(RI)平均值为112.05,西双版纳州茶园土壤整体上存在轻微生态风险。表明在今后茶园管理中要做到科学施肥施药,最大程度地降低人为二次污染风险。

The study investigated concentrations of soil heavy metals in tea gardens of Xishuangbanna. And the pollution status and ecological risks of heavy metals in the soils were assessed by HKANSON potential ecological risk index. The result showed that compared with ＂the Environmental Requirement for Growing Area of Tea＂ and ＂the Green Food Environmental Quality for Production Area＂ and ＂the Environmental Condition for Organic Tea Production Area＂ and ＂the Non-Environmental Pollution Food Environmental Condition for Tea Production Area＂ and ＂the Environmental Quality Standard for Soils＂, the average content of heavy metals in tea gardens soilof Xishuangbanna were all below the limit by the official standards. The average single factor potential ecological risk index（Eir）of heavy metal pollution in the soils was in order of Hg（51.93）Cd（43.55）As（8.32）Pb（5.15）Ni（1.83）Cr（1.23）Cu（0.04）. And only Cd and Hg reached moderate level, while the others were of slight level. The integrated factor potential ecological risk index（RI）of heavy metal pollution in the soils was 112.05, and potential ecological risk analysis suggested a slight risk to local ecosystem originated from heavy metal contamination in the soils of tea garden in Xishuangbanna. Fertilization and pesticide spraying must be managed scientifically in the future, to be maximum decreased secondary pollution risk.