基于水化学和氢氧同位素的泰安城区岩溶地下水补给来源及演化过程  

Recharge Source and Evolution Process of Karst Groundwater in Tai'an Urban Area Based on Hydrochemistry and Hydrogen and Oxygen Isotopes

作　　者：孟令华 MENG Ling-hua(Shandong Geological Prospecting Institute of China Chemical Geology and Mine Bureau,Tai'an 271000,China)

机构地区：[1]中化地质矿山总局山东地质勘查院,泰安271000

出　　处：《环境科学》2024年第4期2096-2106,共11页Environmental Science

基　　金：山东省泰安市城区城市地质调查项目(SDGP370900202002000094,DGP370900202102000047)。

摘　　要：泰安市城区岩溶地下水较丰富,是重要的地下水供水水源地.基于泰安城区岩溶水和地表水的水化学和氢氧同位素(δD、δ^(18)O和~3H)特征,结合Gibbs图解、主要离子比值,揭示岩溶地下水补给来源、补给年代、循环更新能力及主要的水-岩作用演化过程.结果表明,区内岩溶地下水阳离子以Ca^(2+)和Na^(+)为主,阴离子以HCO_(3)^(-)和SO_(4)^(2-)为主,K^(+)、NO_(3)^(-)、Cl^(-)、Na^(+)和SO_(4)^(2-)的变异系数较大,空间差异性较强,Ca^(2+)和HCO_(3)^(-)的含量较稳定.水化学类型复杂多变,主要为HCO_(3)·SO_(4)-Ca型、HCO_(3)·Cl-Ca型和HCO_(3)-Ca型.大气降水是岩溶地下水和地表水的主要补给来源,地下水在径流过程中经历了一定的蒸发作用,但影响性相对较小;岩溶地下水~3H含量介于3.0~5.4 TU之间,与现代水(指1952年核爆以后)水力联系密切,循环更新能力较强,更容易遭受污染,在开发利用时应加强水资源保护.岩溶地下水水化学演化特征受岩石风化作用、阳离子交替吸附作用和人类活动的共同影响,水化学成分主要来源于碳酸盐矿物及少量硅铝酸盐矿物的风化溶解,其演化主要受方解石等贫镁矿物的溶解作用影响,白云岩风化溶解作用影响较小.The karst groundwater in the Tai'an urban area is abundant and is an important source of groundwater supply.Based on the hydrochemical and hydrogen and oxygen isotope(δD,δ^(18)O,and 3 H)characteristics of karst water and surface water in the Tai'an urban area,combined with Gibbs diagrams and main ion ratio,the source of karst groundwater recharge,recharge age,cyclic renewal capacity,and main water-rock interaction evolution process were revealed.The results showed that the main cations were Ca^(2+)and Na^(+),and the main anions were HCO_(3)^(-) and SO_(4)^(2-) in the karst groundwater.The coefficient of variation of K+,NO_(3),Cl^(−),Na^(+),and SO_(4)^(2-) was large,with strong spatial differences,and the content of Ca^(2+)and HCO_(3)^(-) was relatively stable.The hydrochemical types were complex and varied,mainly including HCO_(3)·SO_(4)-Ca type,HCO_(3)·Cl-Ca type,and HCO_(3)-Ca type.Atmospheric precipitation was the main source of supply for karst groundwater and surface water,and groundwater underwent a certain level of evaporation during the runoff process,but its impact was relatively small.The 3 H content of karst groundwater ranged from 3.0 to 5.4 TU,closely related to that of modern water(after the 1952 nuclear explosion),with strong cyclic renewal ability and greater susceptibility to pollution;therefore,water resource protection should be strengthened during development and utilization.The hydrochemical evolution characteristics of karst groundwater were jointly affected by the weathering of rocks,alternating adsorption of cations,and human activities.The hydrochemical composition was mainly derived from the weathering and dissolution of carbonate mineral and a small amount of silica aluminate minerals,and its evolution was mainly affected by the dissolution of magnesium-poor minerals such as calcite,whereas the weathering and dissolution of dolomite had little impact.

关 键 词：岩溶地下水 水化学特征 氢氧同位素 水-岩作用 泰安城区 

分 类 号：X523[环境科学与工程—环境工程]