Hydrochemical Characteristics and Formation Causes of Karst Water in Jinan Spring Catchment

doi:10.3799/dqkx.2017.070

Abstract：Water quality of Jinan spring catchment is getting worse year by year.It is of great significance to find out the pollution sources and influence factors for exploitation of the karst water and ecological environment protection.However,analysis of the whole karst water system including the recharge and runoff area has not been reported yet.Hydrochemical method (piper diagram,ion ratio,correlation analysis) and multivariate statistical method (factor analysis and cluster analysis) were comprehensively used to analyze the hydrochemical characteristics of groundwater,as well as the factors affecting water quality and relevant impact strength in different areas in this study.Factor analysis indicates the effects of water-rock interaction between limestone and groundwater,industrial and domestic pollution,water-rock interaction between dolomite and groundwater,and agriculture,husbandry and domestic pollution.Their contribution rates to groundwater quality are 33.1％,28.4 ％,12.0％,and 11.8％,respectively.Combined with hydrochemical and cluster analyses,the results indicate that groundwater quality in the study area is controlled by both water-rock interaction and anthropogenic activities.Groundwater with high quality in the southern recharge area and western discharge area is mainly affected by the dissolution of carbonate minerals.Some parts of the recharge-runoff area are influenced by agriculture,husbandry and rural domestic pollution with higher content of nitrate in the groundwater.Industrial and urban domestic pollution severely impacts the eastern suburb,urban and suburban exploitation area with poor groundwater quality and excessive levels of SO42-,NO3-,TDS and total hardness in a few sections.