Study on the Total Iodine and Iodine Speciation Characteristics in Xilingol League, Inner Mongolia and Tacheng, Xinjiang High Iodine Area by HPLC-ICP-MS

Long-term drinking of high-content iodine water will cause harm to human health. The analysis of total iodine and iodine speciation in high iodine groundwater is of great value for iodine environmental geochemistry in high iodine regions. In this study, High Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry (HPLC-ICP-MS) was used to analyze the total iodine and iodine speciation of groundwater in Xilingol League, Inner Mongolia and Tacheng, Xinjiang high iodine area. Results show that I^- is dominant in Xilingol League groundwater and the total iodine is maintained at 200 μg/L, with individual points reaching 600 μg/L or even 1700 μg/L. The content of iodine in Xilingol League groundwater is distributed in a circular pattern, showing a 'low-high-low' distribution pattern from northeast to southwest. IO₃^- is dominant in Tacheng groundwater, with the total iodine content of less than 100 μg/L and the individual points are close to 200 μg/L. Moreover, the total iodine content increases gradually from east to west, showing a layered distribution. Oxidation condition is beneficial to the transformation between different iodine speciations. It is not conducive to the iodine enrichment when dissolved oxygen is too high or too low. Iodine will decrease with soluble salt loss. The downstream total iodine content is higher than the upstream content along the flow direction. This study is of significance to the scientific prevention of goiter and the establishment of laws and regulations in Xilingol League and Tacheng.