深圳杨梅坑地区岩石-土壤-植物系统中重金属元素的迁移特征

Migration Characteristics of Heavy Metals in Rock-Soil-Plant System in Yangmeikeng Area,Shenzhen

本文以广东省深圳杨梅坑地区为研究对象,在详细的野外调查和系统的资料搜集的基础上,采集土壤、岩石和芒萁植物样品,研究深圳杨梅坑地区不同地层岩石-土壤-植物系统中重金属元素的含量及分配特征,并揭示重金属元素在岩石-土壤-植物系统中的迁移累积规律。结果表明:(1)从岩石到土壤,春湾组土壤富集Cu、Ni、Cr,南山组土壤富集Pb、Zn、Cd、Hg。土壤在区域上富集特征,与岩石富集特征基本一致,表明地质背景是影响土壤重金属分布的主要因素之一。(2)芒萁对土壤中Cu、Cd元素吸收程度最强,而对As元素吸收程度最低。植物体内重金属的转移能力趋势为Zn>Hg>Cd>Pb>Cu>Ni>Cr>As。(3)在岩石-土壤-植物系统中,As元素的迁移能力极弱,主要集中于土壤和成土母岩中;Pb、Zn、Hg、Cr、Ni在岩石-土壤-植物系统中的迁移较弱,较少受成土母质和母岩的影响;Cd、Cu在岩石-土壤-植物系统中的迁移较强,存在人为引起的来源。

Based on detailed field investigation and systematic data collection,soil,rock and Osmunda japonica plant samples were collected to study the content and distribution characteristics of heavy metal elements in rock soil plant system of different strata in Yangmeikeng area of Shenzhen,Guangdong Province,and to reveal the migration and accumulation rules of heavy metal elements in rock soil plant system.The results show that:(1)from rock to soil,the soil of Chunwan Formation is rich in Cu,Ni and Cr,and that in Nanshan Formation is rich in Pb,Zn,Cd and Hg.The regional enrichment characteristics of soil are basically consistent with those of rocks,indicating that geological background is one of the main factors affecting the distribution of heavy metals in soil.(2)The absorption of Cu and Cd by Dicranopteris was the strongest,while that of As was the lowest.The trend of heavy metal transfer capacity in plants was Zn>Hg>Cd>Pb>Cu>Ni>Cr>As.(3)In the rock soil plant system,the migration ability of As is very weak,mainly concentrated in the soil and parent rock;Pb,Zn,Hg,Cr,Ni in the rock soil plant system are relatively weak,less affected by the parent material and parent rock;Cd,Cu in the rock soil plant system migration is strong,there exiting man-made sources.