Study On Speciation Distribution Of Heavy Metals And Response Of Archaea Community In Surface Sediments Of Caohai,Guizhou

In recent years,heavy metal pollution in rivers and lakes is becoming more and more serious,so heavy metal pollution in sediments has gradually become a research hotspot.Gui Zhou Wei Ning Caohai is the largest plateau freshwater lake in Guizhou Province.Because of the Zinc ore smelting,Caohai is facing fearful heavy metal pollution now.In this periodicals the behavior characteristics and archaeal community response of Lead(Pb),Cadmium(Cd),Copper(Cu),Zinc(Zn),Iron(Fe)and Manganese(Mn)in Caohai surface sediments were studied,and the ecological risk of heavy metals in sediments was evaluated from two aspects of total amount and form of heavy metals.The results are as follows:(1)The mean values of Cd、Zn、Pb、Fe、Cu and Mn in surface sediments of Caohai during dry season are 32.44、614.45、185.30、32008.49、31.07 and 664.01mg/kg.The concentration of Cd,Zn,Pb,Cu and Mn decreased and the concentration of Fe increased in the high water season,and the distribution characteristics changed obviously compared with the dry season.(2)The distribution of heavy metals in sediments shows the same characteristics in two water periods,Cu mainly in the form of oxidizable state and residue state;Mn mainly in the form of weak acid extractable state and residue state;Oxidable state and residue state are the main forms of Fe;Pb、Cd and Zn mainly exist in the form of reducible state and oxidable state.and the reducible state is greatly affected by Fe elements.(3)Cd has the greatest influence on the archaeal community.There is a positive correlation between the reducible state of Cd,Pb,Zn and the archaeal community.The weak acid extractable state of Zn is involved in the metabolism of archaea.Fe element has an effect on many kinds of archaea,but the effect is not good.(4)There are serious ecological risks of Pb and Zn elements in the surface heavy metals of Caohai,while the risks of Cd elements is much more fearful.The health risks caused by heavy metals to the surrounding residents can not be ignored.To sum up,Caohai lake is facing fearful Pb、Zn pollution and Cd pollution is much more serious.The ecological risks is especially severe.