新田县富锶地下水动态特点与成因分析

为掌握湖南省新田县富锶地下水的动态特点,在2017年1-12月对两处富锶地下水进行了一年定期采样分析。结果表明:S045下降泉Sr2+含量在丰水期、平水期、枯水期基本保持稳定,其值分别为0.27 mg·kg-1、0.25 mg·kg-1、0.26 mg·kg-1,S045下降泉Sr2+含量全年保持相对稳定的主要原因是水文地质特点决定了降雨对S045富锶下降泉Sr2+含量的稀释效应有限;ZK1机井Sr2+含量表现为丰水期>平水期>枯水期,其值分别为0.73 mg·kg-1、0.68 mg·kg-1、0.52 mg·kg-1,水循环条件的差异引起水位的变化导致高锶潜流带水与低锶浅潜流带水混合比例不同,使ZK1机井中锶含量与大气降雨具有正相关性。而离子比值法表明:S045下降泉的γ(Na+)/γ(Cl-)比值在丰水期、平水期、枯水期分别为0.78、0.44、0.49,γ(HCO3-+SO42-)/γ(Ca2++Mg2+)比值在丰水期、平水期、枯水期分别为0.99、0.98、0.96;ZK1机井的γ(Na+)/γ(Cl-)比值在丰水期、平水期、枯水期分别为75.24、71.34、126.08,γ(HCO3-+SO42-)/γ(Ca2++Mg2+)比值在丰水期、平水期、枯水期分别为37.13、30.54、44.89,这说明ZK1机井中地下水发生了阳离子交换。S045下降泉的γ(Cl-)/γ(Ca2+)比值在丰水期、平水期、枯水期平均值分别为1.09×10-2、1.06×10-2、1.05×10-2,ZK1机井的γ(Cl-)/γ(Ca2+)比值在丰水期、平水期、枯水期平均值分别为1.29、0.98、0.94,ZK1机井γ(Cl-)/γ(Ca2+)显著高于S045下降泉,表明ZK1机井水水动力条件弱于S045下降泉,这是机井中Sr2+高于下降泉的重要因素。

Dynamic characteristics and genesis of strontium-rich groundwater in Xintian county, Hunan Province

In order to understand the dynamic characteristics of Sr-rich groundwater in Xintian county,Hunan Province,two sites were sampled and analyzed regularly for one year(January to December 2017).The results show that the content of Sr2+in decline spring S045 remains stable in wet,normal and dry seasons with values of 0.27 mg·kg-1,0.25 mg·kg-1 and 0.26 mg·kg-1,respectively.The hydrogeological characteristics determine that the dilution effect of rainfall on Sr2+content in the decline spring S045 is limited,which is the main reason for the relative stability of Sr2+content in this spring throughout the year.The Sr2+content in the ZK1 well decreases in wet,normal and dry seasons with values of 0.73 mg·kg-1,0.68 mg·kg-1 and 0.52 mg·kg-1,respectively.The variation of water level caused by the different water circulation conditions leads to different mixing ratios of high strontium subsurface water and low strontium shallow subsurface water,which is the reason why strontium content in the ZK1 well is positively correlated with atmospheric rainfall.Analysis using the ion ratio method shows that theγ(Na+)/γ(Cl-)in the decline spring S045 is 0.78,0.44 and 0.49,γ(HCO3-+SO42-)/γ(Ca2++Mg2+)is 0.99,0.98 and 0.96,γ(Na+)/γ(Cl-)in ZK1 well is 75.24,71.34 and 126.08,andγ(HCO3-+SO42-)/γ(Ca2++Mg2+)is 37.13,30.54 and 44.89 in wet,normal and dry seasons,respectively.They indicate that the groundwater experienced cation exchange in the ZK1 well.The average values of theγ(Cl-)/γ(Ca2+)coefficients in the decline spring S045 are 1.09×10-2 in wet season,1.06×10-2 in normal season and 1.05×10-2 in dry season,respectively.The average values of theγ(Cl-)/γ(Ca2+)coefficients in ZK1 well are 1.29 in wet season,0.98 in normal season and 0.94 in dry season,respectively.Theγ(Cl-)/γ(Ca2+)in the ZK1 well is significantly higher than that in the decline spring S045,indicating that the hydrodynamic condition of the ZK1 well is weaker than that of the decline spring S045,and it is an important factor for the higher Sr2+content in the ZK1 well than that in the decline spring S045.