氚在典型生物体中的分布、迁移、转化及致毒机制研究

氚是核工业向环境排放的最主要核素之一，其渗透性极强，且进入生物体后能够迅速转化，与蛋白质、核酸等生物大分子结合形成多种多样的有机结合氚或有机氚化合物。生物各组织对不同形态氚的富集和释放能力可能有差异，在生殖系统等长期驻留的氚将可能传递到子代。氚的存在形态不同生物效应亦可能不同，若与靶细胞DNA形成结合物，则会内照射DNA分子，可能引起DNA损伤，启动致突变、致癌过程，严重威胁生物健康。因此，研究氚在生物体内向有机氚的转化过程、动力学、存在形态及各形态氚的生物效应，具有重要意义，然而目前相关研究尤为匮乏。本项目拟发展及运用先进成像技术研究氚进入典型生物体内的平衡过程和界面传输过程，揭示生物体内氚向有机态氚的转化过程和机制，揭示氚存在形态与毒性效应间的内在联系，阐明微观致毒机制；同时考察生物体内富集的氚的亲子传递规律和对子代发育的影响，为氚等放射性核素的环境风险评价提供关键科学依据。

Once tritium that released into environment was bioaccumulated by organisms, their emitted β ray can confer a whole body internal radiological damage, which, thus, seriously threaten the ecosystem. While the nature of exchange between tritium and hydrogen can lead to the transformation of internalized tritiated water (HTO) to organically bound tritium (OBT). The bioconcentration and translocation of these various forms of tritium in tissues and between generation may induce severer toxic effects. Thus, it is essential to investigate the attribution of toxic effects to corresponding transformation process of tritium in vivo. In this project, HTO, which refer to the major emission in nuclear industry, is investigated using various methods, such as radioactive tracer technology, multi-channel microscopic visual platform and modern instrumental analysis techniques. The equilibrium process and interface transport process of HTO and designated OBT were studied to illustrated their bioaccumulation and biodistribution in organisms under scope of tissue, cell and sub-cell. The transformation process of HTO in vivo is revealed by detecting the resulted doses of different forms of tritium distributed in tissues, as well as their retention periods. The causality of toxic effects to tissues and cells, in vivo or in vitro, to the different doses of various forms of tritium are explored to discuss the details of toxicity mechanism induced by ingesting tritium. The transfer of tritium between generation and their influence to the growth and development of offspring are further studied. The results of the study will provide scientific information for the accurate assessment of the ecological risk of tritium and making efficient management policies.