茅洲河流域表层沉积物重金属生态风险评价

为全面了解茅洲河底泥沉积物中重金属污染特征及其生态风险程度，在茅洲干流和支流中共采集34个底泥样品，测试分析As，Cd，Cr，Cu，Ni，Pb，Zn等7种重金属元素含量，并对其污染来源及生态风险进行讨论.研究结果表明，茅洲河流域表层沉积物中重金属元素Pb，Cd，Cr，Cu，Zn，Ni含量较高，均值均超过中国湖泊底泥中重金属平均含量值，其中Cr，Cu，Zn和Ni超过国家海洋沉积物Ⅲ类标准值.7种重金属元素的地积累指数从大到小依次为Cu，Ni~Zn~Cd~Cr，Pb，As，污染负荷指数从大小到依次为Cu，Ni~Zn，Cd~Cr，Pb，As，潜在生态风险指数从大到小依次为Cd~Cu，Ni，Cr~Zn，As~Pb，这说明沉积物主要受到Cu，Zn，Ni，Cd和Cr的污染.

Ecological Risk Assessment of Heavy Metals in the Surface Sediments of Maozhou River

In order to understand the pollution characteristics of heavy metals in the surface sediments of mainstream and its tributaries of the Maozhou river in Shenzhen,the concentrations of 7 metals including Pb,Cr,Cd,Cu,Zn,Ni and As in 34 sediment samples were analyzed.Index of geo-accumulation,pollution load index and potential ecological risk index were utilized to access the pollution level and potential ecological risk of heavy metals.The results showed that the sediments of Maozhou river were characterized by elevated levels of Pb,Cd,Cr,Cu,Zn and Ni,which exceeded the average content of heavy metal in the sediments of lakes in China.According to the national Marine sediments standard,most of Cr,Cu,Zn and Ni were higher than the threshold values of class Ⅲ.In addition,index of geo-accumulation followed the order of Cu>Ni~Zn~Cd~Cr>Pb>As,pollution load index was Cu>Ni~Zn>Cd~Cr>Pb>As and the order of potential ecological risk index was Cd~Cu>Ni>Cr~Zn>As~Pb,which indicated that the sediment was polluted by Cu,Zn,Ni,Cd and Cr.