大同盆地地下水中有机质对碘迁移转化的影响  

Effect of Organic Matter on Iodine Mobilization in Groundwater of Datong Basin

作　　者：赵仕琳 刘文静 孙丹阳 李俊霞[1] Zhao Shilin;Liu Wenjing;Sun Danyang;Li Junxia(School of Environmental Studies,China University of Geosciences,Wuhan 430078,China)

机构地区：[1]中国地质大学环境学院,湖北武汉430078

出　　处：《地球科学》2023年第12期4699-4710,共12页Earth Science

基　　金：国家自然科学基金项目(Nos.42177067,41502230)。

摘　　要：地下水系统中有机质对碘迁移转化起着至关重要的作用,为深入分析地下水溶解性有机质(dissolved organic matter,DOM)对地下水碘迁移转化的影响,研究选取我国大同盆地浅、中层高碘地下水为研究对象,运用傅里叶变换离子回旋共振质谱(FT-ICR-MS)对地下水DOM分子结构进行分析表征.结果表明,地下水总碘浓度变化范围为1.97~926.10μg/L,碘离子是地下水中碘的主要赋存形态;总碘浓度与DOM呈一定正相关关系(r=0.84),与可生物降解有机质含量呈负相关关系(r=-0.71).研究区高碘地下水中有机质生物降解程度较高;高低碘地下水DOM分子组成差异表明,在降解过程中,微生物优先利用CHO、CHON1、CHON2类小分子可生物降解化合物,促使与之结合的碘迁移释放进入地下水;还原环境下地下水中碘主要来源于铁(氢)氧化物的还原性溶解和有机质的降解,且伴随有碘的形态转化,而氧化环境下地下水中碘可能与有机质的分子转化有关.Organic matter plays an important role in the mobilization of iodine in groundwater system.In this study,the high iodine groundwater from shallow and middle aquifers in Datong basin in China was collected to perform the effect of dissolved organic matter(DOM)on iodine mobilization in groundwater.The structure of dissolved organic matter(DOM)in groundwater was characterized by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS).The results show that the range of total iodine concentration in groundwater is 1.97-926.10μg/L.Iodide is the main species of iodine in groundwater.The total iodine concentration has a positive correlation with DOM(r=0.84)and a negative correlation with biodegradable organic matter(r=-0.71),indicating that the organic matter in high iodine groundwater experience more intensive biodegradation.The differences of DOM molecular composition between high and low iodine groundwater further show that microorganisms preferentially use small molecular biodegradable compounds such as CHO,CHON1 and CHON2 to promote the release of bound iodine into groundwater during degradation.The hydrochemical fate of groundwater iodine under the reducing environment is mainly related to the reductive dissolution of iron(hydrogen)oxides and the biodegradation of organic matter,during which iodine species changed,while under oxidizing environment,it could be related to the transformation of natural organic matter.

关 键 词：地下水 碘 迁移转化 溶解性有机质 傅里叶变换离子回旋共振质谱 水文地质 

分 类 号：P641.12[天文地球—地质矿产勘探]