Mobilization and enrichment of geogenic iodine in a floodplain groundwater system: New insights from sources and characterization of dissolved organic matter

作者：Ge Jiang, Chunli Su, Haifeng Liu, Xianguo Wang, Jiaqi Jiang, Jiaqi Li · 发表于：The Science of The Total Environment · 年份：2024 · DOI：10.1016/j.scitotenv.2024.177299 · 被引用次数：8 · 研究领域：Groundwater and Isotope Geochemistry、Atmospheric and Environmental Gas Dynamics、Marine and coastal ecosystems

High iodine groundwater occurs widely in the lower reaches of Yellow River floodplain, which has aroused public concern. The biogeochemical behavior of dissolved organic matter (DOM) plays a crucial role in the mobilizing iodine from aquifer media. In this study, the molecular composition of DOM in groundwater characterized by FT-ICR-MS, and the optical properties of organic matter obtained by combining three-dimensional fluorescence spectroscopy and parallel factor analysis (EEM ⁃ PARAFAC), were used to elucidate the effect of DOM on the migration and enrichment of iodine in groundwater in the eastern Henan Plain, which is located in the lower reaches of Yellow River floodplain, Northern China. The results show that，the total iodine concentration in groundwater in the study area is ranged from 4.68 to 1598 μg/L, and the average value was 216.4 μg/L. High iodine groundwater shows a distribution pattern along the Paleochannels of Yellow River, which is closely related to the richness of organic matter in the buried sediments of the Paleochannels of Yellow River. Organic matter in the sedimentary aquifers plays an important role in regulating the mobilization and enrichment of iodine, and its degradation process is conducive to the release of iodine. DOM components in high iodine groundwater are more homogeneous, more unsaturated, and has more aromatic molecules than those in low iodine groundwater. The activation of organic iodine in groundwater system may be accompanied by th...