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In a three-year study, the possible biological concentration of 3H in rabbits was investigated. Tritiated water was used to grow alfalfa that was used exclusively as feed for the rabbits. Feed and water were kept at a constant 3H-to-1H ratio. The foundation group consisted of 18 female rabbits maintained on a 3H diet for 2 wk before mating. The subsequent generations were maintained with tritiated water and feed. At appropriate intervals, animals were sacrificed and selected tissues were analyzed for 3H. The specific activity of 3H in aqueous and organic fractions of tissues of all the animals remained essentially equal to that in the original water and feed. Results of this experiment indicate that under the steady-state equilibrium conditions of the experiment, no preferential concentration of 3H in animals occurred.

An evaluation of available personnel monitoring data and radium body burden records of dial painters handling an annual average of 1.5 Ci of radium indicates that they received an average of about 2 rem/person whole body exposure, 3 rem to the lungs from radon inhalation and 0.2 rad to the bone from radium body burdens. Among groups of similar workers handling tritium in Texas plants, the highest occupational exposures were about 160 mrem annually per person received by refinishers of tritium dial timepieces and back-lit watch assemblers. Based upon scenarios of exposures to 147Pm, repairers of timepieces containing 147Pm receive about 4.4 X 10(-4) mrem/person/yr whole body dose equivalent. The amounts that they process are in the microcurie range. Although the trend is away from the use of radium as a luminizing activator, there are indications that it is still used in timepieces even as tritium and 147Pm are increasingly being used for this purpose.