= 25
products and exchangeable caleium in the soil, and variations in what
constitates the root sone of these particular plants,
Strontivwe-90 and Cesiwe-137 in Meat and Milk
Cesiu-137 in the diet of cattle is believed te come almost antively fron direst contamination on the plant. That entering the sail
is beund up to abeut 99% and hense 49 not taken up by the plant. what
Ce~137 is ingested goes to biced emt soft tissues.
The great bulk of
it is found in the body muscle mass, like potassiua, it turns over
bs
fairly rapidly in the body with a balf reaidense time in humana of
about 110 days. In contrast to the case with Sr-90 the body content
Bem
of Ca-137 reflects more nearly the rate of intake and is not ousulative.
In other words, the equilibrium state is achieved in a few months, In
the cow, Ce-137 is oxereted in the silk as well as in the urine,
Major sources of Cse-137 in our diets are thus meat and milk, Aa long
as the rate of testing in terms of fMisslon preduct yield remains what it is
Ca-137 as an internal radioactive contaminant in huaan beings will be rel-
atively insignificant. (See earlier section on Ce~137/K-10 ratio.)
In mammals Sr-90, like caleium, is found for the nost part, over 992
of it, in the bone.
Therefore, meat is exceedingly low in Sr-9) and is
a@ relatively Sr-90 free and equally caleium-free item of the diet.
Heat
containg only about 10% the caloium per unit of wet weight that ailk does,
Uptake studies of Sr-90 in milk-free diets in rats, goats, and humans
indicate diserimination against Sr-90 in favor of calolum of about 25%.
According to Comar, Sr-90 in milk is less diseriminated against, about
HRB