山区路侧土壤-油菜系统重金属来源及关联特征

Correlation characteristics and source of heavy metals in roadside rape and soil system in mountainous areas

以安顺市至龙天村部分路段位置为基准,选取不同坡度采集距路侧不同距离、高度的油菜及表层土壤样品,测试了各样品中Cu、Pb、Cd、Cr、Zn、Ni、Hg、As元素含量,分析了路侧油菜与土壤中重金属的可能来源、分布规律及表层土壤组成的差异。结果表明:道路截面灰尘有机质含量较高;油菜土壤质地粗细不一,侵入类型以砾石、生活垃圾为主;表层土Cd的Igeo值最高为6.94,属极重污染,Cr、Pb属轻污染;油菜重金属Cd、Cr主要来源地质背景,Pb、Zn、Ni主要受非点源污染源路线影响,Hg、As、Cu与地质背景和人为活动有关;油菜组织重金属含量最大值主要集中在路侧10m内,叶、茎、根中Cr、Cd超标极其严重,分别为:14.49、12.96、15.54倍,35.13、9.54、19.72倍;5m处油菜叶、茎、根对As、Hg、Cr、Pb、Zn、Ni、Cu的富集能力远高于10 m、30 m处。

Rapes and corresponding surface soil samples from different locations with different roadside distances in partial position as reference of the road between Anshun City and Longtian Village were collected.The contents of heavy metals including Cu,Pb,Cd,Cr,Zn,Ni,Hg and As in the samples were analyzed.The possible sources and distribution regulations of the heavy metals and the differences of surface soil composition were studied.The results show that the organic matter content is very high in road section dusts;the particle sizes of the rape soil texture are different,and the types of the invasions are dominated by gravels and domestic wastes.The highest Igeo value of the surface soil Cd is 6.94,belonging to heavy pollution,while the Cr and Pb are in slight pollution.The main source of heavy metal Cd and Cr in the rapes is geological background,and the Pb,Zn,Ni are mainly affected by non point source pollution sources and Hg,As,Cu are related to the geological background and human activities.The maximum value of the heavy metal in the rapes is mainly concentrated within 10 m of the roadside.The contents of Cr,Cd in the leaves,stems,roots respectively are 14.49,12.96,15.54 times and 35.13,9.54,19.72 times,which exceed the standard extremely serious of rape.The enrichment ability of leaves,stems,roots in 5 m is maximum and geometric multiple higher than those in 10 m or 30 m.