Chemical Characteristics And Evolution Of Groundwater In Dongfeng-Lake Spring Area,Shexian County

Shexian is located in the Taihang Mountains in the west of Handan City,Hebei Province,and dongfeng Lake region is located at the border between Shexian County,Hebei Province and Licheng County,Shanxi Province.Under the influence of increasing artificial mining and decreasing atmospheric precipitation year by year,the spring flow of Dongfeng Lake presents a trend of decreasing year by year on the whole.Due to the influence of industry and human activities,such as Tianjin Iron Works in Shexian county,a series of ecological and environmental problems have been caused by the changes in the content of chemical components in groundwater and the changes in the hydro-chemical field.Therefore,it is of great significance for groundwater planning,groundwater environment and social and economic development of Dongfeng Lake spring basin to study the chemical evolution of groundwater in the spring basin.In this paper,through Piper trigraph,main ion isoline,Cluster analysis and factor analysis,social network analysis,Gibbs graph,ion proportion method and hydrogeochemical simulation,the spatial and temporal distribution characteristics,ion formation,and hydrogeochemical characteristics and evolution of the chemical components of groundwater in the study area are systematically analyzed.The results show that:(1)according to the east lake spring field in recharge area,runoff area and discharge area of groundwater chemical distribution characteristics,groundwater chemical characteristics mainly by supply conditions better,runoff way short and long-term leached,chemical type of groundwater salinity and water have little difference,salinity between 290-650 mg/L,hydrochemical type is mainly HCO3-Ca Mg or HCO₃-Ca.(2)The distribution patterns of Ca²⁺,Mg²⁺and SO₄^2-are similar in space and time according to the ionic isoline map in the past ten years.The content in the recharge area is low,and with groundwater runoff,the content in the discharge area reaches the maximum.K⁺,Na⁺and Cl^-ions have similar distribution rules in space and time,and the variation coefficient is highly susceptible to external influences.Due to the influence of industrial and human activities such as Tianjin Iron works,the content reaches the maximum in the area with strong runoff from Gengle to Xigang.(3)Through Cluster analysis,social network analysis and factor analysis,the hydrochemical characteristics of the research area in 2015 and 2019 are systematically analyzed to find out the main factors affecting the hydrochemical characteristics of the research area.According to Gibbs map and ion ratio method,the main factors affecting the components of karst groundwater in the study area are rock weathering and cation exchange Na⁺-Ca²⁺,and Ca²⁺in groundwater is replaced with Na⁺in soil minerals.(4)Hydrogeochemical simulation showed that in 2015,the flow path I of the study area from the recharge area to the discharge area occurred calcite,gypsum and rock salt dissolution,dolomite precipitation,and cationic alternate adsorption was Ca²⁺-Na⁺.In 2019,the migration amount of these minerals in the study area increased,and cationic alternate adsorption was Na⁺-Ca²⁺in contrast to that in 2015.2015?flow path from the runoff area to discharge area evolution of calcite,rock salt precipitation,dolomite,gypsum dissolution,cation exchange for Na⁺,Ca²⁺ions,2019in the flow path?evolution law and the result is the same in 2015.