Abstract
Rats were kept in a metabolic cage through which air containing tritiated water vapor was passed at a constant rate. Tritium activity in their blood and urine was found to increase with increase in tritium activity in the air. The absorption ratio of tritiated water (the ratio of tritium activity in the blood or urine to that in air) was constant even with change in humidity. By continuous inhalation of tritiated water vapor (10.1 pCi/ ml air), activity in urine increased gradually with time and attained to about 70 nCi/ml after 140 h. The initial rate of tritium intake was found to be 1.4 × 10-4 C Bq/min/rat, where C is tritium activity in ambient air (Bq/m3). Tritium activity in various tissues except adipose tissue was similarly increased after starting exposure of the rats to tritiated water vapor. In addition, tissue-bound tritium activity was also found to be 3-10% of wet-tissue activity.
