湖南新田富锶地下水水化学特征与成因分析

Hydrochemical Characteristics and Formation Mechanism of Strontium-rich Groundwater in Xintian County,Hunan Province

研究湖南新田富锶地下水水化学特征及成因,为富锶地下水的可持续利用与开发提供理论依据。对研究区21个下降泉、30个机井富锶地下水样品的水化学类型、化学成分含量特征、成分间相关性以及离子比值的研究。结果表明:下降泉水化学类型全部为HCO_3-Ca型,机井水化学类型以HCO_3-Ca、HCO_3-Ca·Mg型为主。相关分析表明,下降泉和机井中SO_4^(2-)与Ca^(2+)、Mg^(2+)均表现显著相关或极显著相关,HCO_3-与Ca^(2+)、SO_4^(2-)与NO_3^-在下降泉与机井中的相关性具有差异,下降泉、机井Sr与Ca^(2+)、Mg^(2+)、HCO_3^-均表现为极显著相关。Gibbs图表明下降泉和机井的水化学组成主要受水-岩相互作用的控制,下降泉、机井c(Ca^(2+))/c(Mg^(2+))、c(HCO_3^-)/c(SO_4^(2-)+Cl^-)、c(Na+)/c(Cl-)、c(Cl^-)/c(Ca^(2+))系数比值具有差异。结果表明富Sr地下水的形成受碳酸盐岩成分影响显著,赋存条件的差异导致富锶地下水在下降泉、机井中的水化学特征、相关性以及离子系数比值的差异。

To provide a theoretical basis for the sustainable utilization and development of strontium-rich groundwater,we described the chemical characteristics and discussed the possible origin of the strontium-rich groundwater in Xintian,Hunan. The hydrochemical types,chemical compositions,and correlations between components and ionic ratio of strontium-rich groundwater samples from 21 descending springs and 30 wells are presented. The results show that the chemical types of descending springs are all HCO3-Ca type,whilst those of wells are mainly HCO3-Ca and HCO3-Ca · Mg types. The correlation analysis shows that the SO42-and Ca2＋andMg2＋in the descending springs and the wells are colsely correlated,and HCO3-vs. Ca2＋,SO42-vs. NO3- correlations are different in the descending springs and the pumped wells. Strontium is strongly correlated with Ca2＋,Mg2＋and HCO3-in descending springs and wells. Gibbs control chart shows that decrease of water spring and well chemical composition is mainly affected by water rock interaction,and the Ca2＋/Mg2＋,HCO3-/（ SO42-＋ Cl-）,Na＋/Cl-,Cl-/Ca2＋ratios are different in descending springs and pumped wells.All the results show that the formation of Sr-rich groundwater is significantly affected by the carbonate composition. The difference of the reservoir conditions may have led to the varying hydrochemical characteristics,correlation and the ratio of ionic coefficient of strontium-rich groundwater in descending springs and pumped wells.