Hydrogeochemistry In The Process Of Seawater Intrusion In Longkou Area,Shandong Province

Bohai Sea area is one of the most serious areas of seawater intrusion in China,which is also a hot area to study the cause of salt water and seawater intrusion.The seawater intrusion in this area began in the 1960 s,which not only threatened the groundwater quality,but also brought a series of ecological environmental problems such as soil salinization,agricultural production reduction,and seriously hindered the development of social economy.In order to control the seawater intrusion and realize the rational development and utilization of groundwater,Longkou City,Shandong Province was taken as an example,on the basis of collecting geological data and hydrogeological data,comprehensively using hydrochemistry analysis,stable isotope tracing,reverse geochemical simulation and other means,the hydrogeochemistry in the process of seawater intrusion was revealed in the study area.While the fuzzy theory was also used in this study.The degree of seawater intrusion is evaluated by mathematical method.The results show that the hydrochemical types of groundwater in the study area are mainly HCO3.Cl-Na.Ca and HCO3.Cl-Ca,and the groundwater samples in the whole study area generally show the evolution from HCO3-Ca to HCO3.Cl-Na to Cl-Na from the inland to the coastal.The results of stable isotope analysis show that the main source of groundwater in the study area is atmospheric precipitation,while it is affected by different factors of seawater intrusion degree and the evaporation.In the seawater intrusion process in the study area,the mixing of seawater and fresh water took place firstly,and then different degree of cation exchange and mineral dissolution and sedimentation took place.According to the results of reverse geochemical simulation,reverse ion exchange and different types and degrees of mineral dissolution and precipitation took place via different ways.The comprehensive evaluation results of fuzzy mathematics method suggest that most groundwater samples indicating the seawater intrusion degree in the study area is relatively light,and a few groundwater samples indicating the seawater intrusion degree close to the coastline is relatively serious.