Chemical Characteristics Analysis And Water Quality Evaluation Of Shallow Groundwater In Shizuishan City

Shizuishan is located in the arid and half arid areas.Most of the water layer mining purpose for phreatic water and the first confined water,so the analysis and research to the region water chemical characteristics and control factors of groundwater.Groundwater quality is deteriorating and grasp the region for reasonable development of groundwater,groundwater pollution control,have very important significance to protect the safety of traditionalists drink water supply.This paper takes Shizuishan between shallow groundwater as the research object,by using descriptive statistics,C.A.шукалев classification,Piper diagram,Gibbs figure,ion ratio method and correlation analysis and influencing factors of groundwater chemical characteristics,through the routine descriptive statistical methods for organic.Inorganic and toxicity index analysis of the characteristics,Single factor index evaluation method and fuzzy comprehensive evaluation method are used to evaluate the quality of shallow groundwater in the study area.The single factor index evaluation method and the improved Nemello comprehensive index method are used to evaluate the groundwater pollution which is easily affected by human activities.The factor analysis method is used to extract the groundwater pollution sources and analyze the sources and causes of pollutants.So as to provide a scientific basis for the rational development and utilization of groundwater and water environment protection.The results show that:(1)From north to south,the hydrochemical types of phreatic water mainly transition from Cl-SO4-Na type water to HCO3·Cl-Na·Mg type water,and these two types of water are the main ones.The first hydrochemical type of confined water mainly transition from north to south from Cl·SO4-Na type water to HCO3·Cl-Na·Mg·Ca type water,and these two types of water are the main ones.The spatial distribution values of TdS,Th and Na+,Cl+ ions,Mg2+and SO42-,K+and Ca2+are basically the same.The Cl-and SO42-ions in phreatic water and the first confined water all come from the dissolution of evaporite such as rock salt and mirabilite.The majority of Na+comes from the dissolution of evaporite such as rock salt and mirabilite.Ca2+and Mg2+dissolved in silicate aluminate minerals and evaporite dissolution.The chemical components of phreatic water and the first confined water are mainly affected by rock weathering and evaporation and concentration,and positive cation exchange occurs.(2)The quality of phreatic water and the first confined water in the study area was excellent.The water quality of phreatic water in the study area was 89.47%above Ⅲ grade,10.53%at the level of N and Ca grade,86.49%at the level of first confined water,and 13.51%at the level of N and Ca grade.In phreatic water,the exceeding rate of sulfate,TDS,chloride,Mn and total hardness is more than 50%,among which the exceeding rate of sulfate is the most serious.In the first confined water,the exceeding rate of sulfate is the same as that of phreatic water,which is the most serious index.The inorganic toxicity indexes in the phreatic water and the first confined water,F-,NO3-,and As all exceed the standard.(3)After comparing with the background value,six pollution components in the inorganic routine indexes exceeded the standard:sulfate(SO42-),TDS,chloride ion(Cl-),manganese(Mn),zinc(Zn)and total hardness;three inorganic toxicological components exceeded the standard:ammonia nitrogen(NH4+-N),nitrite nitrogen(NO2--N)and nitrate nitrogen(NO3--N).The volatile phenol,cyanide,Hg,Cr6+and Pb were all unpolluted,and the other 10 indexes showed different degrees of pollution.The most serious index above the severe pollution grade was NH4-N,with a proportion of 39.5%,followed by Mn,with a proportion of 34.2%.Because the single index evaluation method is more strict.The result is more serious.Most of the water samples are polluted;TDS,total hardness,Cl-,SO42-,Mn and ammonia nitrogen are the primary factors affecting the phreatic water pollution in the study area.Spatial distribution characteristics of comprehensive pollution sources:Gaozhuang Township and Chengguan Town in the central part and Hongyazi Township-Taole Township-Gaoren Township in the east have high scores of comprehensive pollution factors;Weiza Township in the north also has a certain degree of pollution;and a large area along the mountain in Dawukou in the west has relatively good groundwater quality.