Abstract: We studied the distribution and metabolism of tritium, and its transfer from mother to offsring, also estimated the absorption dose, in rats and mice. The results show that: 1) tritium is evenly distributed in mice body fluids and tissues accroding to the law of exponential decline, and retention curves are generally resolved into two exponential components; 2) the first biological half-life oftritium for non-pregnant mice is 2 days or so, while that for pregnant and lactating mice is about 1.6, 1.7 days respectively, and metabolism of tritium in normal, pregnant and lactating mice is basically the same; 3) the activity of tritium in the tissues of rats is unevenly distributed, and the retention on the 15th day accounts for about 9% of that on the 1st day; 4) the total and organic tritium in the tissues of rats of the tritiated wheat group is significantly higher than that for the tritiated water; 5) tritiated water can be absorbed into the body through the injured skin, and the importance of injury degree for absorption is cutting wound > scald> chemical burn; 6) tritium in pregnant and lactating mice can be transferred to embryonic and newborn mice by different ways, with the transfer coefficient between 1.06 and 2.37; 7)the cumulative absorption dose in normal, pregnant and lactating mice is 8.5, 6.7 and 7.1 mGy respectively.

Key words: Tritium, Distribution, retention and transfer, Tritium activity in tissue, Absorption dose