Accumulations and risks of heavy metals in the sediments from 8 typical lakes in Wuhan, China

Abstract

采集武汉市8个典型湖泊的表层沉积物,分析11种重金属的含量及其不同形态组成,研究了不同湖泊金属元素的富集与污染程度,探讨了沉积物中重金属的污染来源及其潜在生态风险.结果表明,沉积物中重金属Cd累积最严重,Zn和Hg也发生明显累积,龙阳湖污染较重,南太子湖和墨水湖污染中等,其它湖泊污染总体较轻.沉积物性质对重金属累积的影响不显著,城市工业活动强烈影响着重金属的分布.不同重金属的形态分布差异较大,Cd生物可利用态含量最高,其次为Mn、Zn、Co、Cu和Pb,而Sb和Hg以残留态占绝对优势,生态风险较小.相关分析和主成分分析表明,化石燃料燃烧、金属冶炼等是武汉市湖泊沉积物中重金属来源的主要贡献者,同时岩石风化等地球化学过程也影响着重金属的污染.;The content and species of 11 heavy metals in surface sediments from 8 typical lakes located in Wuhan, China, were investigated, and the accumulation, contamination, potential ecological risks and possible sources of metals were discussed in this paper. According to the metal geoaccumulation indexes, the results showed that the lake sediments had heavily polluted by Cd and evidently by Zn and Hg. On the whole, heavy pollutions of metals were observed in Lake Longyang and medium pollution in Lake Nantaizi and Lake Moshui, whereas the slight pollution in other lakes. Distribution of metals in sediments was observed to be not significant correlation with physicochemical properties of sediments, whereas distinctly influenced by urban industries. 11 metals distributed differently in lake sediments. The largest percentage of the form of available speciation was Cd in the lake sediments, with much higher potential ecological hazards, followed by Mn, Zn, Co, Cu and Pb. In contrary, As, Sb and Hg were dominantly associated with the residual fraction, indicating rare adverse biological effects. Correlation analysis and principal component analysis indicated that the heavy meal accumulation in the lake sediments were mainly attributed to the combustion of fossil fuel accompanied with metal refining, and followed with the effects of the biogeochemical processes of earth weathering.