Effluents containing tritium (H) dispersed into the fresh water or marine environment from nuclear facilities can be taken up by biota. Aquatic and marine organisms are among the important pathways through which tritium can enter into the human body, and hence, assessment of the extent of pollution of these ecosystems is very important for radiation dose assessments. Tritium present in environmental matrices can be classified as tissue-free water tritium (TFWT) and organically bound tritium (OBT). Optimization of a method for the determination of OBT in fish, based on thermal oxidation of the sample, is discussed. Samples were subjected to thermal oxidation in a pyrolyser system, and the water produced from the combustion was analyzed by liquid scintillation spectrometry. Results show that a maximum of ~2 g of processed fish sample can be combusted efficiently in the pyrolyser. Using this method, a recovery of 84% was achieved, and minimum detectable activity (MDA) for the method was determined to be 8.5 Bq kg (sample weight = 2 g, counting time = 30,000 s, and detection efficiency = 20%).

中文翻译：

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采用热氧化和液体闪烁计数法测定鱼中有机结合氚 (OBT) 浓度。

从核设施扩散到淡水或海洋环境中的含氚（H）流出物可以被生物群吸收。水生和海洋生物是氚进入人体的重要途径之一，因此评估这些生态系统的污染程度对于辐射剂量评估非常重要。环境基质中存在的氚可分为无组织水氚（TFWT）和有机结合氚（OBT）。讨论了基于样品热氧化的鱼类 OBT 测定方法的优化。样品在热解器系统中进行热氧化，并通过液体闪烁光谱法分析燃烧产生的水。结果表明，最多约 2 克加工过的鱼样品可以在热解器中有效燃烧。使用该方法，回收率达到 84%，该方法的最小可检测活性 (MDA) 确定为 8.5 Bq kg（样品重量 = 2 g，计数时间 = 30,000 秒，检测效率 = 20%）。