Distribution Characteristics And Risk Assesment Of Heavy Metals In Sediments Of Riparian Bank In The Xiaobai River Of Typical Outbound River

In this study,cross-border River White River as the research object,the status quo of ore dressing nonferrous metal mining area wastewater on river pollution based on the sediment surface through the middle,and determination and speciation of heavy metals in the bottom,a preliminary study of heavy metal concentration of sediments in the study area and the main forms of different heavy metals,to investigate the temporal and spatial distribution characteristics in sediments,and the heavy metals in the sediments of risk analysis,which can provide the theoretical basis for similar treatment of heavy metal pollution in the river and conduct regular dredging The main conclusions are as follows:(1)The law is different along the flow direction of heavy metals varies,showing B,change of D content is more than C section of cross section;variation of the content of Cu was higher than the export entrance content;As,Zn in January,April,July showed a change law of entrance was higher than that of exports,a variation in the opposite October;Mn in January,changes in July showed a higher content of export entrance,is the contrary rule in 10,4;Co in October,January,April showed a variation of export content is higher than the entrance,is the contrary rule in July.At the same time,due to the difference of 2,3,4 sampling sites,the distribution of heavy metals in different sampling sites is different.(2)The vertical distribution characteristics of heavy metals in the riparian zone sediments are different.As,Cu and Co are the characteristics of surface enrichment,In October,April and January,the content of Mn in sediments was lower than > middle layer > surface distribution,the content of Zn shows the distribution law of middle layer > bottom > surface layer,in July,the distribution of Mn in sediments was lower than surface > middle.(3)The riparian sediments in As,Co,Cu are mainly in residual form;Mn mainly exists in October sediment extractable form;Zn in the surface and bottom sediments mainly exists in sediment extractable form,mainly in the middle of residual forms of.1Co in the bottom sediments mainly exist extractable form;July sediments Mn,Zn mainly existed extraction form.(4)Study on surface sediments in the region in different forms of As showed the changes of B section >C section >D section;different forms of Co,Mn changes between extractable showed a trend showing an overall D section >C section >B section Cu;variation of different forms of the differences in extractable was presented B section >D section >C section;Zn variation of different forms are different,extractable was showing an overall D section >B section >C section.The different forms of heavy metals in vertical distribution is different,with the increase of sampling depth,showed the overall content of heavy metals in the residual state was significantly reduced Less.(5)The heavy metal pollution is serious,Mn,Zn,As,Cu,Co were the main pollutants,high ecological risk,As,Zn,Mn is the main ecological risk factor,but the RAC risk assessment index method showed that the heavy metals in the surface sediments of Mn,the highest content of available Zn,As does not exist in the ecological risk in the environmental assessment.The governance,to the evaluation results of several evaluation methods of comprehensive consideration,not only to pay attention to the environmental risk of heavy metals,and can not be ignored by the direct use of biological environmental risk of heavy metals brings.