Hydrogeochemical Characteristics And Formation Mechanism Of Shallow Groundwater In Northwestward Ruijin City

The research purpose of this project is based on shallow groundwater in northwestern ruijin as the research object,on the basis of the study area 30 Jane analysis and 20 group full analysis of testing data,the shallow groundwater in the study area to study the hydrogeochemical characteristics of using descriptive statistics,DTM model,piper diagram,hydrogen and oxygen isotope tracer method and inside plum luo index method;Secondly,the formation of groundwater chemical components in the study area is studied by gibbs model method,correlation analysis method,ion proportional coefficient method and principal component analysis method.On this basis,through the analysis and study of the hydrogeochemical characteristics and their formation in the region,the research results and conclusions are as follows:(1)Mathematical and statistical characteristics of hydrochemistry in the study area:the soluble total solid content indicates that the groundwater is fresh water.The p H indicates that the groundwater in most areas is neutral water.The total hardness of groundwater shows that the groundwater in most areas is extremely soft water according to the average ion content.The coefficient of variation shows that the more stable indexes are ph,bicarbonate and calcium ion,and the unstable indexes are potassium ion,sulfate and chloride ion.(2)Research the internal chemical space distribution characteristics: p H,total soluble solid,sodium,calcium,magnesium,potassium,bicarbonate root,sulfate and chloride ion content and its spatial variability are characterized by strip changes,the content of the research index and degree in southern accumulation valley area in north-central erosion and corrosion butte valley now groundwater are significantly higher than in northwest and southeast low mountain hills now;The variation trend of the concentration of calcium ion and bicarbonate in the spatial range is highly consistent,and the variation trend of sodium ion and chloride ion is also highly consistent.(3)The hydrochemical characteristics of the shallow groundwater in the region are as follows: the alkaline earth metal-bicarbonate water is mainly distributed in the whole region,and the alkali metal-non-bicarbonate water is only found in the magmatic metamorphic rock fracture water;(4)The characteristics of hydrogen and oxygen isotopes in the study area are as follows: the groundwater in the study area originates from meteoric precipitation,and the evaporation is weak in the process of groundwater formation by precipitation infiltration.The isotope value in groundwater is mainly dominated by the initial value of precipitation in the recharge area and is negatively correlated with elevation;(5)Water quality characteristics of the study area: among them,22 evaluation indexes reached the limit of groundwater quality standard,the compliance rate reached94%,and the exceeded index was nitrate.Good water samples accounted for 60.0%,good water samples accounted for 34.0%,poor water samples accounted for 6.0%.(6)Dissolution and filtration is the main factor affecting the formation of water chemical composition in the study area,in which carbonate dissolution and meteoric precipitation play a leading role,and it is also an important source of calcium,bicarbonate,magnesium,chlorine,potassium and sulfate ions.Evaporation concentration is a secondary factor,in which the dissolution of a small amount of silicate rock is the dominant factor,which is an important source of magnesium ions.