北京北部水系沉积物中重金属的研究

Analysis of heavy metals in sediments of the water system in the north of Beijing

主要研究了北京市北部水系沉积物中重金属(As、Hg、Cd、Cr、Cu、Mn、Ni、Pb、Ti和Zn)含量和来源.在潮白河及密云水库流域采集了17个沉积物样品,温榆河流域采集了5个样品,重金属含量As和Hg采用原子荧光光谱法测定,Cd、Cr、Cu、Mn、Ni、Pb、Ti和Zn含量用电感耦合等离子发射光谱法测定.研究结果表明,沉积物中重金属元素没有出现明显的富集状况,只有Hg、Cd、Cr和Zn在一些采样点有较高的富集.相关性分析表明Hg、Cd、Zn和Cu互相之间呈显著正相关(r>0.06;p<0.01),而Hg与Cr、Mn、Ni、Pb和Ti没有明显的相关性.通过主成分分析研究重金属的来源,发现前3个主成分贡献率分别为38%、23%和17%.因此,Hg、Cd、Zn和Cu作为第一主成分被认为与人类活动的工矿业开采有关,第二主成分As和Mn与人类活动的农业生产和生活污水排放有关,第三主成分Cr、Ni和Ti与岩石风化和土壤侵蚀有关.

Contents and sources of heavy metals（As,Hg,Cd,Cr,Cu,Mn,Ni,Pb,Ti and Zn） in the sediments of northern Beijing were researched in this article.We collected 17 samples from the basin of the Chao River,Bai River and Miyun Reservoir and 5 samples were from Wenyu River.Contents of As and Hg in the sediments were analyzed by AAS.Cd,Cr,Cu,Mn,Ni,Pb,Ti and Zn were analyzed by ICP-OES.The results showed that the heavy metals were not obviously enriched in sediments,whereas the enrichment of Hg,Cd,Cr and Zn were relatively high in some sediments.Correlation analysis indicated that significant correlations existed among Hg,Cd,Cr and Zn（r 0.06;p 0.01）,however,Hg had no significant correlations with Cr,Mn,Ni,Pb and Ti.Principal component analysis was applied to estimate the sources of heavy metals.Results showed that the first three components accounted for 38%,23% and 17% of the total variance.The first principal components included Hg,Cd,Zn and Cu,which were considered to come from developed industry and mining.The second principal components included As and Mn,which are likely from agricultural contamination and sewage.The third principal components included Cr,Ni and Ti,which were considered to come from rock weathering and soil erosion.