Distribution Characteristics Of Heavy Metals From New Submerged Area And The Influence On Water Quality Of Reservoir Bays In Danjiangkou Riservoir

After the heightening of the Danjiangkou reservoir dam,new submerged area is 205km~2.After submerged,the soil heavy metals migrated and exchanged into the water through the soil water interface,thus affecting the water quality safety.In this paper,we selected heavy metals in soil and water from new submerged area of Danjiangkou reservoir as the study object.Based on the data of remote sensing images,land use,hydrological regime,meteorology,soil and heavy metal content in the study area,this study used couple of arcgis theory and technology,ecological risk assessment,statistics and other research methods to assess the risk of heavy metals and analysis sources apportionment of heavy metals pollution.The main results are as follows:(1)The average concentration of Cd was higher than that of the background value,while the average concentration of Cr was lower.The concentration of As,Cu,Pb,Ni and Zn were not different from the background value.Spatial analysis showed that the concentration of Cd,Cr,Pb,Ni,Mn,Zn and As in the Dan River Reservoir were higher than that in the Han River Reservoir.The evaluation results of enrichment characteristics showed that the enrichment level of Cd is the most important pollution element in the new submerged area,which mainly affected by human activities.In addition,As has a high potential risk.The results of multivariate statistical analysis showed that the heavy metals in farmland soil of new submerged area were mainly from 3 ways: Cr,Cu,Ni,Mn,Pb and Zn were the main input of natural source;whereas Cd and As were mainly affected by the influence of human activities.Cd was mainly affected by industrial and domestic waste,while As mainly affected by agricultural production activities.(2)We analyzed distribution characteristics and source apportionment in farmland soil of the new submerged area in Danjiangkou Riservoir by couple of enrichment factor and multivariate statistical analysis.The results showed that: The content of heavy metal and spatial variability of the heavy metal in bays were different from which in the period of wet and dry season.In rain seasons,Pb exceeded the national standards for drinking water quality,followed by As.The coefficient of variation of Cd and Mn were higher than one,which were highly variable.During dry seasons,As and Pb were highly variable.The results showed that the water quality of the reservoir was poor.The water quality was excellent during the dry season,and the integrated water quality index was 17.6.The water quality of Danjiangkou reservoir bays in the dry season was better than that of the rainy season.The results demonstrated that heavy metals in reservoir bays were mainly came from three ways.In rainy seasons,human activities greatly affected the concentration of As,Mn and Pb.Non-point source pollution were the main reason affected As and Mn;Pb was the comprehensive effect of non-point source and point source pollution;Zn,Cr,Cd,Ni and Cu mainly originated from natural sources.During the dry season,human activities greatly affected the concentration of Pb and Cd;while Cu,Cr,As,Zn,Ni and Mn mainly for natural input.(3)Based on multivariate correlation analysis,we studied the influence of heavy metals in farmland soil on heavy metals content in reservoir waters in Danjiangkou reservoir.The results showed that there was no significant correlation between both heavy metals.The migration and transformation of heavy metals in farmland soil were less harmful to water quality in the Bay,while water environmental factors were the main factors affecting the concentration of heavy metals in the reservoir waters.