开封城郊河道底泥重金属形态垂向分布特征及风险评价  

Vertical distribution characteristics and risk assessment of heavy metals in core sediments from Kaifeng suburban rivers

作　　者：张俊华[1,2] 卢翠玲[1,2] 刘玉寒[1,2] 王洪涛[1,2] 

机构地区：[1]河南大学环境与规划学院黄河文明传承与现代文明建设河南省协同创新中心,河南开封475004 [2]河南大学资源与环境研究所,河南开封475004

出　　处：《农业环境科学学报》2017年第6期1192-1201,共10页Journal of Agro-Environment Science

基　　金：国家自然科学基金(U1404401;41101088);河南省高校科技创新团队支持计划项目(161RTSTHN012)~~

摘　　要：为了解开封河流底泥中重金属垂直迁移与生态风险问题,分层采集了开封城郊三条河道底泥剖面样品,采用连续提取法测定底泥中Cd、Cr、Cu、Ni、Zn和Pb等6种重金属的赋存形态及总量,用风险评估编码法进行底泥重金属的污染评价。结果表明,底泥样点中Cd、Cu、Zn和Pb含量远高于中国水系沉积物背景值,不同采样点底泥剖面中重金属形态含量随深度变化特征存在显著差异,且没有呈现出一定的分布规律性;河流下游底泥剖面样点中Cd、Cr、Cu、Ni、Zn和Pb含量高于河流上游底泥中重金属含量,Cd和Zn以弱酸可提取态与残渣态为主,Cr、Cu、Ni和Pb以残渣态为主。风险评估编码法评价结果表明,表层(0~10 cm)底泥重金属对环境构成的风险大小依次为Cd>Zn>Cu>Ni>Cr>Pb;在剖面上,Cd以高和极高风险等级为主,Zn处于中等风险到高风险等级之间,Cu和Ni处于轻微到中等风险等级之间,Cr和Pb以轻微风险级为主。To understand the migration characteristics and ecological risk problems of heavy metals in sediments of Kaifeng suburban rivers,vertical sediments from three rivers were collected and analyzed for total concentrations and speciation of heavy metals by using the sequential extraction procedure, and risks from exposure to heavy metals in sediments were evaluated using the risk assessment code method. The results indicated that the mean contents of Cd, Cu, Zn, and Pb were higher than the China Stream Sediment Background Values. There were significant differences in vertical distributions of total concentrations and different species concentrations of heavy metals in the sediment cores from six sampling sites, however there was no distribution regularity. Sediment profiles from the lower section of each river showed significantly higher total concentrations of Cd, Cr, Cu, Ni, Zn, and Pb than those from the upper sectin. Cd and Zn existed mainly in the exchangeable fraction and residual fraction, whereas Cr, Ni, Cu, and Pb existed mainly in the residual fraction. Based on the results from the RAC method, the risks from exposure to heavy metals in the surface sediments were in the following order：Cd 〉Zn 〉Cu 〉Ni 〉Cr 〉Pb. In the vertical sediments, Cd mainly posed high to extremely high risk to the environment, Zn a medium to high risk, Cu and Ni a slight to medium risk, and Cr and Pb slight risk.

关 键 词：开封城郊 底泥剖面 重金属形态 风险评价 资源化利用 

分 类 号：X820.4[环境科学与工程—环境工程]