Exposure to radionuclides and cancer incidence: distribution of 241Pu-citrate in neonatal and young adult mice following exposure throughout pregnancy

An experiment describing the uptake and distribution of plutonium in neonatal mice following chronic exposure throughout pregnancy is described. In order to maintain a near constant availability of the radionuclide to the fetus and placenta throughout pregnancy subcutaneously implanted Alzet osmotic pumps have been used. After birth ∼1% of infused activity (%IA) was retained within each pup. By 8 days this was ∼0.5%IA; 0.1%IA in the organs of the pup, the remainder in the gastrointestinal tract (GIT). By weaning (day 21) GIT activity has fallen forty fold but absolute activity in the organs of the pup had increased, on average around 20% as a result of exposure via lactation. Samples taken from pups up to 180 days old were used to estimate clearance half-times after weaning. Using these values average organ doses expected in the pups of dams exposed to between 0-70 kBq 239Pu.kg-1 were calculated for the period 7-180 days old. (author)