不同功能区土壤-钩藤系统重金属累计特征及评价

以不同功能区土壤及钩藤为研究对象,探讨了不同功能区土壤和钩藤中重金属含量,分析了重金属在钩藤中的富集特征,并对不同功能区土壤重金属污染进行评价,结果表明:土壤中铜(Cu)、砷(As)、铅(Pb)和铬(Cr)表现为耕地林地荒地,镉(Cd)表现为林地耕地荒地,汞(Hg)表现为耕地荒地林地;参照《土壤环境质量标准》,Cd在林地、耕地和荒地下均超过了一级标准,林地下Cd超过了二级标准,耕地和荒地下Hg超过了一级标准;以《绿色食品产地环境技术条件》为标准,林地下土壤Cd超过了标准规定的限量值;依据《药用植物及制剂进出口绿色行业标准》,3种功能区下钩藤中重金属均符合标准;从单因子污染指数来看,林地土壤受到重金属Cd的污染;从综合污染指数来看,钩藤在不同功能区下土壤都没有受到重金属的污染;钩藤钩对Cu,Cr,Pb,As的富集系数为荒地林地耕地,荒地下钩藤钩对重金属Cu的富集系数大于1;除Cu外,其余重金属富集系数均比较低。

Evaluation and cumulative characteristics of heavy metals in soil-Uncaria rhynchophylla system of different functional areas

Soil and Uncaria rhynchophylla in different functional areas were selected for the study,the content of heavy metals such as As, Cd, Cu, Cr, Pb, and Hg in soil and U. rhynchophylla was discussed, the characteristics of their accumulation in the U.rhynchophylla was analyzed, the contamination levels of heavy metals in soil in different functional areas was evaluated. The results showed that content of Cu, As, Pb and Cr in soil was being cropland > woodland > wasteland, content of Cd was being woodland > cropland > wasteland, content of Hg was being cropland > woodland > wasteland. According to quality standard of soil environment, soil Cd in woodland, cropland and wasteland all exceeded the state-level standards, soil Cd in woodland exceeded the secondary standard, soil Hg in cropland and wasteland all exceeded the state-level standards. According to technical conditions of green food producing area, soil Cd in woodland exceeded the limit value of standard. According to Green Trade Standards of Importing Exporting Medicinal Plants Preparations,the content of heavy metals of U.rhynchophylla in cropland,woodland and wasteland were correspond to the specification. From the single factor pollution index, the soil in woodland was polluted by Cd. From the comprehensive pollution index, the soils in different functional areas were not contaminated by heavy metals. The enrichment coefficient of heavy metals such as As, Cu, Cr, and Pb in hook of U.rhynchophylla was being wasteland > woodland > cropland, the enrichment coefficient of Cu in hook of U. rhynchophylla in wasteland was more than 1. Except Cu, the enrichment coefficient of other heavy metals was low.