矿区道路两侧雪岭云杉叶片重金属富集效应

摘要

采矿及矿产品运输过程会对环境造成重金属污染进而对生物体产生危害.为定量描述艾维尔沟矿区道路两侧重金属污染程度、明确雪岭云杉叶片对重金属的吸收富集效应,通过采集雪岭云杉叶片和土壤样品,测试其铅(Pb)、锌(Zn)、镉(Cd)、砷(As)、铜(Cu)、铬(Cr)的含量,分析重金属的富集效应和空间分异特征.结果表明:(1)雪岭云杉叶片和土壤中各重金属含量差异显著(P＜0.05),叶片中Pb的含量显著高于其余重金属(P＜0.05),平均达86.28 μg/g,土壤中Zn、Cu超过了国家土壤质量标准的一级限制值,而As比三级限制值大41％;(2)以背景区(板房沟林场)的土壤和雪岭云杉叶片重金属为评价标准,研究区雪岭云杉叶片重金属综合污染指数为2.05,属中度污染,其中As和Pb单项污染指数较高,达3.65和2.57.研究区土壤重金属综合污染指数为1.69,属轻度污染;(3)随距离增加,除土壤和叶片中Pb含量表现为负线性递减外,As和Cu均表现为先升高后降低,土壤中Cr、Zn逐渐升高,但叶片中Cr逐渐降低,Zn变化不大;(4)冗余分析(RDA)结果显示土壤中Cu、As、Pb与雪岭云杉死树胸径和树高呈正相关关系,而Cr、Zn与其呈负相关.采矿及运输已对土壤和雪岭云杉的生长造成影响,本文对天山雪岭云杉森林的生态修复与保育具有一定的借鉴作用.%Mining and the transportation of its products can contaminate the environment with heavy metals,which can accumulate in organisms.Pollution caused by these effects in Ewirgol,China,was described quantitatively,and the accumulation of heavy metals absorbed by the leaves of Picea schrenkiana,a dominant tree species in the Tianshan District,was investigated.Leaf and soil samples were collected from the roadside in Ewirgol mining area,within a vertical distance of 0-500 m to measure the As,Cd,Cr,Cu,Pb,and Zn contents.Thus,the enrichment effect and spatial differentiation characteristics of heavy metals were analyzed.The results showed that the heavy metal contents of soils and P.schrenkiana leaves varied significantly (P＜0.05);Pb content in leaves,with an average value of 86.28 μg/g,was significantly higher than that of other heavy metals (P＜ 0.05).Cu and Zn contents exceeded the first level in the Environmental Quality Standard for soils,and As was 41％ higher than the third level.Furthermore,heavy metals in soils and P.schrenkiana leaves in Bangfanggou,approximately 50 km south of (U)rümqi,were referred to as the criteria evaluating pollution.The comprehensive pollution index of heavy metals in leaves was 2.05,which indicated moderate pollution,and the single pollution indexes for As and Pb were higher at 3.65 and 2.57,respectively.The soil pollution index was 1.69,indicating light pollution.As the distance from the road increased,Pb content in soil and leaves decreased along a negative linear gradient;the contents of both As and Cu first increased then decreased.Soil Cr and Zn contents increased gradually with increased distance from the road,but Cr content in leaves gradually decreased,while that of Zn remained stable.Lastly,redundancy analysis showed that soil As,Cu,and Pb were positively correlated with diameter at breast height and height of dry wood,with negative correlations for Cr and Zn.Therefore,soils and P.schrenkiana trees in the study area were affected by the transportation of mining products,and ecological restoration and conservation in this area is critical.