98
RADIATION STANDARDS, INCLUDING FALLOUT
means that the rate-dependent process will be dominant.
The level of Cs” in
the diet has not fallen as rapidly as expected from the decrease in fallout rate,
probably because of a holdup in the root mat of pastures.
For future predictions it is probably best to base estimates of the cumulative
component on comparison with Sr assuming that absorption of Cs’” from soil
is less by a factor of 10 to 25, but that efficiency of secretion into milk is greater
by a factor of 10. Estimates of the rate component are best determined by
comparison of known fallout rates and milk levels in the past.
Roughly, 60 percent of the dietary Cshas been contributed by dairy products,
25 percent by meat, and 15 percent by plant foods.
BADIOACTIVITY IN TOTAL DIET
It is of interest to compare the relative daily intakes of various radionuclides,
both natural and man made. Typical values expressed in picocuries per day
are listed as follows (I. Michelson, personal communication) :
K*
Cs'*
Sr®
Ce
4,000.0
50.0
10.0
4.0
Natural.
“1961.
1961.
1961.
Pu”
0.1
1961.
Pb”
Ra**
4.0
2.0
Natural.
Natural.
It should be noted, however, that possible effects on the population must take
into account many other factors besides the amounts ingested. It is beyond
the scope of this report to consider such an assessment.
finibale
Gedecwntin
PIERNR SUT