Study On The Formation Of Chemical Composition Of Jinan Karst Spring Water

Jinan spring water has played an important role in Jinan's economic construction and urban prosperity.With economic and social development,a series of water environment problems such as deterioration of water quality have been caused.Therefore,only by grasping the formation and influencing factors of the chemical composition of spring water,can we put forward scientific and effective spring water quality protection measures.This article mainly focuses on Jinan karst springs as the research object.Based on the collection of the previous water quality data of Jinan springs,combined with hydrogeological data and groundwater monitoring research data for many years.It conducts spring water collection,hydrochemical testing,and spring water dynamic monitoring.Start with data such as water chemical composition,water temperature and conductivity,using ion scale coefficient method,Gibbs free graph,hydrogeochemical simulation,factor analysis method,cluster analysis,correlation analysis,saturation index method,gray correlation analysis and sodium ion Adsorption ratio method and other methods are used to analyze the chemical composition difference,formation effect and influencing factors of Jinan karst spring water.Found in study:(1)The chemical types of groundwater in Zhangxia Formation of Cambrian are mainly HCO₃·SO₄-Ca and HCO₃-Ca,and the average TDS is 498mg/L.The groundwater chemistry types of Ordovician?Cambrian Chaomidian Formation are mainly HCO₃·SO₄-Ca,HCO₃-Ca,HCO₃-Ca·Mg,and the average TDS is 512mg/L.The four springs have various chemical types(HCO₃·SO₄·Cl-Ca·Mg,HCO₃-Ca·Mg,HCO₃·SO₄-Ca·Mg,HCO₃·SO₄·Cl-Ca),and the spring water quality is excellent.From2017 to 2020,the mineralization of spring water increased significantly,in which the content of Ca²⁺and Mg²⁺decreased,and the content of Na⁺increased.(2)According to the conductivity and temperature change curves of the four spring groups.It can be seen that the water circulation depths of Baotu Spring and Heihu Spring are different,and Tanxi Spring and Zhenzhu Spring have similar exposure conditions.It can be seen from the clustering results that Yinsi Spring in the Heihuquan Spring and Baotu Spring,Ma Pao Spring,and Qianjing Spring in the Baotu Spring Group may receive groundwater replenishment from the same aquifer.The hydraulic connection between Baotu Spring and Wulongtan Spring is poor.The Black Tiger Springs and Baotu Spring and Wulongtan Spring have different sources of groundwater replenishment.(3)Research on spring water quality data based on ion scale coefficient method,Scheler index method,correlation analysis and factor analysis method found that the ions in spring water mainly come from the dissolution of minerals.Precipitation,the difference in the chemical composition of spring water is mainly affected by hydrogeochemical effects such as leaching,dissolution and precipitation,cation exchange,evaporation and concentration,decarbonization,mixing,and dedolomization.Natural and man-made factors such as limestone leaching,cation exchange,external interference,mineral dissolution,acid-base evolution,etc.,make Jinan's karst water different in the interannual water chemical composition.(4)According to the changes in spring water chemistry from 2017 to 2020.It's found that the carbonate minerals in the Jinan spring area from 2017 to 2018 are mainly the dissolution of limestone and dolomite,while the Jinan spring from 2019 to2020 The carbonate minerals in the domain are mainly the dissolution of limestone and gypsum.Based on the changes in the saturation index of calcite,dolomite,and aragonite in the spring water samples taken from 2017 to 2020,we can see the mineral change process of the spring water.The circulation of groundwater may cause a large amount of carbonate rock salt to continuously dissolve,making calcite and dolomite in the spring water.The state of stone and aragonite has experienced a state of unsaturated-equilibrium-supersaturated state.(5)Groundwater solutes are affected by water-rock effects such as dissolution,sedimentation and mixing in the runoff process.The aquifers of the Ordovician-Cambrian Zhangxia Formation replenish the four springs with better runoff conditions through groundwater.Among them,the Ordovician-Cambrian aquifer in the south direction has a very small amount of mineral transfer,indicating that the south is The facing Ordovician-Cambrian aquifer is not only a good water storage space but also a good supply source.