Study On Material Source Characteristics And Health Risk Assessment Of Groundwater In Buckwheat Field

The buckwheatland basin is located in the Jinsha River basin in the upper reaches of the Yangtze River.It is located in the eastern slope of the Jidong Plateau and the excessive slope of the Sichuan Basin.It is a plateau three-dimensional climate with a distribution from the south subtropical to the cold temperate zone.The area has abundant rainfall,clear and wet conditions,rain and heat in the same season,abundant light and heat resources,obvious three-dimensional climate,diverse climate resources,water shortage and water pollution problems.Groundwater resources are the main source of domestic production and domestic water supply.The study on the material source and health risk assessment of groundwater hydrochemistry in the buckwheatland basin has the important development and utilization of groundwater in the southwest karst area.This research collects the hydrogeological and environmental geological survey reports made by the predecessors in the buckwheatland basin,and collects and collates the geological structure,topography,hydrology,meteorology and other materials of the study area,and in July 2017 and March 2018.Conduct relevant surveys,and on the basis of reviewing domestic and foreign related literature,field collection of water samples and data analysis,study the material source and health risk assessment of groundwater chemistry in buckwheatland watershed.Research indicates:The main anions and cations in the groundwater of the buckwheat field are HCO₃^-and Ca²⁺,respectively.The water chemical types are complex,and there are HCO₃-Ca type,HCO₃-Ca·Mg type,HCO₃-Na·Ca type and HCO₃-Na·Ca·Mg type.It is characterized by the control of the carbonate balance system.The physical and chemical parameters of water in the study area show obvious spatial differences due to human activities and geological background.During the flood season,the human activities of the buckwheat field are more active,and some heavy metal elements in the water exceed the standard;in the dry season,due to the watershed The evaporation is large,the precipitation is insufficient,and the aquifer in the clastic rock area is poorly water-rich,and the spring water in the clastic rock area is severely interrupted.From the water samples collected,the content of NO₃^-and SO₄^2-can be found to be low.In the high water period,and the coefficient of variation is also small,and NO3-and SO₄^2-can some extent characterize the intensity of human activity,so it can be considered that the degree of human activity in the dry season has decreased.In addition,this paper selects pH,Na⁺,K⁺,Mg²⁺,SO₄^2-,Ca²⁺,HCO₃^-,Cl^-,NO₃^-,Si,DO,TDS,SIA,SIC,SID and SIG values for cluster analysis,factor analysis and path model.Analysis and multivariate statistical analysis of groundwater hydrochemical samples can be used to determine that carbonate rocks,human activities,evaporites and silicates are the main sources of groundwater during the wet season,where human activities and MgSO₄ evaporation The dissolution of rock is the main source of the formation of carbonate rock as the chemical component of groundwater,and it has important reasons for the chemical characteristics of multiple groundwater.During the dry season,carbonate rock is the main material source from the distribution of samples and the changes of NO₃^-and SO₄^2-content.The health risk assessment of groundwater body reflects the control of the main geological background of groundwater health risk assessment in buckwheatland watershed,the impact of human activities is limited,and the health risk assessment of children is complicated in terms of spatial distribution compared with adults,and the watershed is judged.The internal groundwater pollution path has three modes:vertical infiltration through the aeration zone,vertical infiltration through the upper aquifer,and lateral infiltration.Therefore,the main source of groundwater chemistry and heavy metals in the buckwheat field is controlled by geological background.