The genetic and late somatic effects of chronic tritium ingestion in mice.

The long term somatic and genetic effects of chronic tritium (3H) ingestion have been measured in mice. Second generation animals, who with their parents were maintained on drinking water containing 3 muCi/ml of HTO, have been bred and the number of dominant lethal mutations measured. The increase in dominant lethal mutations in treated animals as compared to tap water controls is significant at the 1% level. The stem cell content of the bone marrow has been measured throughout the lifetime of the animals. A slight reduction in colony forming units in the bone marrow of treated animals is evident beginning after approximately 12 weeks, increasing in severity throughout the lifetime of the animals. The distribution of tritium in tissue water protein fractions was determined, and the relative contribution to tissue dose calculated. The differential incorporation into protein fractions was not found to be significant.