广西会仙岩溶湿地水体主要离子和溶解无机碳来源及控制因素  

Sources and control factors of main ions and dissolved inorganic carbon in karst water of the Huixian karst wetland,Guangxi

作　　者：赵一[1,2] 邹胜章 申豪勇[1,2,3] 蓝芙宁 谢浩 李军[4] ZHAO Yi;ZOU Shengzhang;SHEN Haoyong;LAN Funing;XIE Hao;LI Jun(Institute of Karst Geology,Chinese Academy of Geological Sciences,Guangxi Karst Resources and Environment Research Center of Engineering Technology,International Research Center on Karst Under the Auspices of United Nations Educational,Scientific and Cultural Organization,Guilin 541004,Guangxi,China;Pingguo Guangxi,Karst Ecosystem,National Observation and Research Station,Pingguo 531406,Guangxi,China;Department of Earth Sciences,University of the Western Cape,Cape Town 7535,South Africa;Hebei Key Laboratory of Water Quality Engineering and Comprehensive Utilization of Water Resources,Hebei University of Architecture,Zhangjiakou 075000,Hebei,China)

机构地区：[1]中国地质科学院岩溶地质研究所、广西岩溶资源环境工程技术研究中心/联合国教科文组织国际岩溶研究中心,广西桂林541004 [2]广西平果喀斯特生态系统国家野外科学观测研究站,广西平果531406 [3]西开普大学地球科学系,南非开普敦7535 [4]河北建筑工程学院市政与环境工程系,河北省水质工程与水资源综合利用重点实验室,河北张家口075000

出　　处：《中国地质》2024年第5期1701-1713,共13页Geology in China

基　　金：广西自然科学基金(2021JJA150041,2023JJD150024);中国地质调查局项目(DD20230425,DD20230081,DD20221758)联合资助。

摘　　要：【研究目的】为查明会仙岩溶湿地水体主要离子和溶解无机碳(DIC)的来源及控制因素。【研究方法】于会仙岩溶湿地采集地下水和地表水样品,分析了水化学和溶解无机碳同位素(δ^(13)CDIC)参数特征。【研究结果】会仙岩溶湿地大部分的地下水和地表水水化学类型为Ca−HCO_(3)。湿地水体Ca^(2+)、Mg^(2+)与HCO_(3)^(−)主要来源于碳酸盐岩溶蚀;NO_(3)^(−)主要来源为农业化肥和土壤有机氮的硝化;K^(+)、Na^(+)和Cl^(−)主要来源为化肥、粪肥和污水等;SO_(4)^(2−)主要来源为酸雨和硫铁矿的氧化。湿地地下水中DIC主要来源于土壤CO_(2)和碳酸盐岩矿物的溶解,据同位素质量平衡,计算结果显示约46%来自于土壤CO_(2),约54%来源于矿物本身的贡献。会仙岩溶湿地不完全是CO_(2)参与下碳酸盐岩风化的结果,含硫矿物、酸雨和人类活动来源的H_(2)SO_(4)作为侵蚀介质也参与碳酸盐岩的风化,此外,农业输入还原态氮肥的硝化作用不容忽视。湿地地表水中DIC主要来源于地下水,湿地地表水中δ^(13)CDIC值受水生植物的光合作用和CO_(2)脱气的影响,组成较地下水相对富集偏正。【结论】水化学和δ^(13)CDIC可以帮助理解岩溶湿地的风化和生物地球化学过程,同时还应结合湿地水文地质和人为活动等条件才能提供更准确的信息。This paper is the result of hydrogeological survey engineering.[Objective]In order to determine the sources and control factors of main ions and dissolved inorganic carbon(DIC)in water of the Huixian karst wetland,[Methods]groundwater and surface water samples were collected from the Huixian karst wetland to analyze the hydrochemical ions and dissolved inorganic carbon isotope(δ^(13)CDIC).[Results]The Ca−HCO_(3)water was identified as a main hydrochemical type in most water samples of the Huixian karst wetland.The dissolution of carbonate rock was primary contributor to Ca^(2+),Mg^(2+)and HCO_(3)^(−),while NO_(3)^(−)was mainly derived from synthetic fertilizers and soil organic nitrogen.Moreover,K^(+),Na^(+),and Cl^(−)were driven by the mixed inputs of synthetic fertilizer,manure,and sewage,and the acid rain and pyrite oxidation contributed more to karst water SO_(4)^(2−).Further,karst water DIC was respectively derived from the soil CO_(2)with the contribution rate of 46%and from the carbonate minerals with the contribution rate of 54%according to the obtained result from isotopic mass balance.In addition to the H_(2)CO_(3)produced from CO_(2)and H2O,the H_(2)SO_(4)derived from sulfur−containing minerals,acid rain,and anthropogenic emissions was involved in carbonate weathering in the Huixian karst wetland.Additionally,microbial nitrification processes of the reduced nitrogen fertilizers could be also ignored in the study area.For the surface water,the DIC was mainly derived from groundwater recharges,and the value ofδ^(13)CDIC was affected by the photosynthesis of aquatic plants and CO_(2)degassing,thereby resulting in the more enrichment ofδ^(13)CDIC compared with that in groundwater.[Conclusions]The obtained results provided insights into the understanding of minerals weathering and biogeochemical processes,and also highlighted the control factors of hydrogeological conditions and human activities in precisely determining hydrochemical mechanisms in the karst wetland.

关 键 词：岩溶湿地 水化学 溶解无机碳同位素 来源 控制因素 水文地质调查工程 桂林市 广西 

分 类 号：P342[天文地球—水文科学] P641.12[天文地球—地球物理学]