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Exposure to External and Internal Radiation
Evaluation of Hazards from Tritium--Dominant Lethal
Project Title: Mutations in Mice
13.
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RX-01-01-(c)
Publications:
Elias, J. M,, Conkling, K., and Makar, M.
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effect on displacement of tritiated thymidine.
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Cold fuelgen hydrolysis;
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(in press).
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Scope:
‘A)
200 Word Summary:
With the increasing number of power reactors, there is a growing concern
as to the genetic and somatic effects resulting from exposure to radioactive
reactor effluents,
Critics contend that the present radiation safety
Standards,
enough,
from a genetic and long-term somatic standpoint, are not stringent
The objective of these studies is to ascertain if dominant lethal
mutations are induced in mice by exposure to 1-100 times the present
maximum permissible concentrations (MPC's) of tritium in water.
B)
Supplement to 200 Word Summary:
Parent (P,})
animals are fed on tritiated water commencing at
four weeks
of age. Four weeks later, when their tissues are nearly in equilibrium with
HOH-3, they are mated.
The offspring (F,) are maintained on tritiated water
“ ™,
throughout the remainder of the experiment.
At eight weeks of age they are
divided into three experimental groups and mated as follows: group one,
:
consisting of tritiated males mated to tritiated females; group two, consist--
ing of tritiated males mated to untreated females; and group three, consisting
of tritiated females mated to untreated males.
This allows an estimate
of the effect on the male and female germ cells separately and also detection
of any interaction if it exists. Initially each experimental group, receives
100 times the MPC.
An additional group of untreated controls also is exam-
ined.
Histological examination of pre-implantation zygotes is made on a
sufficient number of animals to establish that pre-implantation and early
post-implantation deaths are due to chromosome abnormalities of the type
characteristic for dominant lethal mutations.
Serially sectioned ovaries
from the F,; mice are microscopically analyzed to enumerate the number of
surviving ova.
For comparison, additional groups of x-irradiated animals
will be studied,
meas
ae concentration of tritium in body water and DNA of cells is,
.» The complete tritium analysis includes determination of the
amoulg.0 f activity in the wet tissue, dried residue (freeze dried), DNA,
RNA, histones, and residual chromosome associated protein.
From these
data the dose to ova and testes will be calculated, probable effects
estimated, and these compared to observed effects in order to determine if
there is any unique and unexpected effect from tritium in germ cells.
(See Continuation Sheet)
Pi Tglss
RX-25