Comparative stochastic effects from low level exposure of mice to tritiated water

A total of 1,133 C57 Black/6M mick of both sexes were randomly assigned to 5 experimental groups. In the first group, mice received a single injection of tritiated water (HTO) at weaning time. In the second group, weaned mice were exposed to tritated drinking water for the entire lifespan. In the third group the female parent received one single injection of HTO following delivery. In the fourth group, the female parent and her progeny were exposed to tritiated drinking water for the entire lifespan. In the fifth group, dams were exposed to tritiated drinking water from the beginning of pregnancy for the entire lifespan. (Drinking HTO 1 μCi/ml; single dose of HTO 1 μCi). Data from experimental groups were statistically evaluated vis a vis extensive control groups (+- 1,000 control mice of either sex). All mice were autopsied as moribund or soon after death and tissues were microscopically examined. A significantly increased incidence of reticulum cell sarcomas was observed in female offspring from dams in the third and fifth groups. A significantly increased incidence of hepatic tumors was observed in male offspring in the fourth group. Mean survival times did not significantly differ within experimental groups but were significantly different from controls