Abstract: Iodinated X-ray contrast media (ICM) is a crucial class of medical pharmaceuticals widely used for the diagnostic imaging of vascular organs and soft tissues. However, the extensive global utilization of ICM has resulted in its frequent detection in aquatic environments. ICM exhibits strong polarity and biochemical stability, making it a great challenge to effectively remove via conventional sewage treatment technologies. Recent studies have demonstrated that the migration and transformation of ICM in natural aquatic environment has led to the emergence of iodinated organic pollutants. Moreover, ICM is the primary source of organic iodine in aquatic environments and an important precursor of iodinated disinfection by-products. Consequently, the presence of ICM in aquatic environments poses a severe threat to both the ecological environment and human health, attracting extensive attention from scholars worldwide. Based on this background and the current research hotspots of ICM, this review comprehensively summarizes the pollution status of ICM, as well as its environmental fates and transformation processes. It systematically introduces the currently reported degradation technologies of ICM and their corresponding degradation mechanisms, with a focus on the roles of various free radicals involved in these degradation technologies of the ICM degradation process. Specifically, this review conducts a systematic analysis of the degradation pathways of ICM by various reactive oxygen species and identify the differences in reaction sites and mechanisms among. Furthermore, to gain insight into the generation process of iodinated organic pollutants during the degradation process of ICM, the present study performs an in-depth analysis of the transformation pathways of iodine element released during this process and finally summarizes the key steps in the generation of iodinated organic pollutants, such as iodinated disinfection by-products. These discussions will help deepen the understanding of the degradation process of ICM and provide a theoretical basis and practical reference for the development of high-efficiency and low-toxicity degradation technologies for ICM degradation.

Key words: iodinated X-ray contrast media, high-efficiency and low-toxicity degradation technologies, reactive oxygen species, iodo-disinfection byproducts

摘要： 碘代X射线造影剂(Iodinated X-ray Contrast Media, ICM)是全球使用最为广泛的医学显影药剂，在水环境中频繁被检出。ICM极性强且生物化学稳定性高，传统污水处理技术难以有效去除。此外，ICM是水环境中碘代污染物的关键前驱体，严重威胁生态环境和人体健康。基于ICM的研究热点，本工作系统梳理了ICM的污染现状、环境归趋与转化过程，以及ICM降解技术和降解机理。在此过程中，本工作聚焦于各类自由基，尤其是活性氧物种在ICM降解中的作用及其作用位点和机理。此外，本文深入剖析活性氧物种降解ICM过程中碘元素的转化路径，并总结了碘代消毒副产物等碘代有毒物质产生的关键步骤。这些探讨将有助于深化对ICM降解的认识，为ICM高效低毒降解技术的研究提供理论依据和实践参考。

关键词: 碘代X射线造影剂, 高效低毒降解技术, 活性氧物种, 碘代消毒副产物