Study On Hydrochemical Characteristics And Health Risk Assessment In The Second Songhua River Basin

In this paper,relying on the environmental protection bureau of jilin province project,aiming at the existing problem of the second songhua river basin,in data collection,field investigation,sample collection and test analysis,on the basis of system data analysis technology and water chemical analysis,methods of water environmental quality assessment was carried out by the second songhua river basin water chemical characteristics of surface water and groundwater and pollution risk assessment studies.The results show that:1.Generally speaking,the surface water of the basin is weakly alkaline and relatively stable.The cation in the surface water is mainly Ca²⁺,the anion is mainly HCO₃^-,and the hydrochemical type is mainly Ca-Mg-HCO₃.The hydrochemical components are influenced by the factors such as rock weathering,evaporation and concentration,and atmospheric precipitation,mainly by the weathering and ion exchange of rocks.The impact of industrial activity in human activities is greater than that of agricultural activities.2.Generally speaking,the groundwater in the basin is weak alkaline,and the change is relatively stable.The TDS mean value is less than 1,and belongs to freshwater.There are 15 kinds of hydrochemical types,mainly Ca-Mg-SO₄ type.Chemical composition of groundwater formation mainly by evaporation and rock weathering mainly accompanied by ion exchange,the main reaction for dissolution of calcite,dolomite and gypsum,in addition to industrial production and human activities on groundwater chemical composition influence.The TDS of shallow groundwater increased from upstream to downstream,and the NO₃^-concentration in most areas exceeded the standard limit of drinking water.3.The groundwater in the basin is dominated by type IV and v.The water quality in the middle and upper reaches is better for drinking,and the water quality of the deep groundwater is better than that of the shallow groundwater.The factor caused by groundwater pollution in the study area are mainly NO₃^-and Cl^-,the groundwater in the study area are subject to different degrees of pollution,the main pollution category for class II and class III and IV,the total of 84.62%sampling points,sampling points IV and V class a total of 10,accounting for the total of 38.46%sampling points.4.All samples of the total non carcinogenic risk index is in the range of 0.51-5.72,the non carcinogenic risk index of 19 samples of 23 shallow groundwater samples exceed the limit,overrun rate is 82.6%,the high risk of regional distribution in the mid west plain in the study area,this area belongs to the agricultural activities of strong irrigation area and densely populated area.