黄河包头段河流沉积物重金属污染的多样性与均匀性分析

采用生态学中常用的Shannon-wiener多样性指数与Pielou均匀度指数,以黄河包头段干流4个站位和支流2个站位的柱状沉积物中铜、铅、锌、镉为目标元素,以2 cm为间隔分层分析了其次生相重金属含量、潜在生态风险指数、沉积物重金属质量基准的多样性和均匀性。结果表明,黄河包头段沉积物重金属污染存在较为显著的空间异质性,当测定元素种类固定时,沉积物重金属污染的多样性和均匀性具有相同的变化趋势。该研究区干流重金属污染的元素趋于多样性和均匀性,但引起其潜在生态危害的重金属元素却趋于单一;支流的趋势与之相反。引起黄河包头段潜在生态危害的重金属元素的种类和总量具有增加的趋势,而沉积物重金属质量基准由于综合了较多的评价信息,使其空间分异的变化更为复杂。多样性指数与均匀度指数可以较好地指示引起河流重金属污染元素组成的变化趋势和污染的空间分布特征,这有助于加强河流重金属污染治理的多样化和针对性。

Analysis of diversity and evenness of heavy metal pollution in river sediments of Baotou section of the Yellow River

The column sediments were sampled with the depths of 2 cm from surface layer of four stations in trunk and two stations in branches from the Baotou section of the Yellow River,and the heavy metals such as copper, plumbum,zinc and cadmium were measured in each layer.Diversity and evenness of the heavy metals' content in secondary phase,the potential ecological risk index and the sediment quality criteria were calculated by the Shannon-wiener diversity index and Pielou evenness index.The results indicate that there is notable spatial heterogeneity of heavy metal pollution in sediments of the Baotou section in the Yellow River.There are similar change trends of diversity and evenness of heavy metals' pollution when the measured elements are the same in sediments.The pollution elements tend to be multiple and even,and the potential ecological risk elements tend to be simple in the trunk.But the situation of the branch is opposed to that of the trunk.The types and gross of the heavy metals bringing potential ecological risk are increasing,and the spatial variance of the sediment quality criteria becomes more complex because of more estimate factors.The cases show that the diversity and evenness indexes can preferably indicate the change of the components and distribution of the heavy metal pollution,which is helpful to enhance the diversification and pertinence for the control of the heavy metal pollution in river sediments.