-llAgricultural Organization and data on the non-milk drinking populations is slowly becoming available.
The three principal types of samples taken for analysis are
(1) vegetation, including beth animal and hiumen food, (2) milk,
and (3) human bone.
Vegetation
Sr-90 may occur in vegetation in either of two routes.
Sr-90 from the soil may be taken up by the root system and incorporated into the plant.
deposited on the plant.
In addition, fallout may be directly
Part of this letter material may be
washed off by rain but a considerable portion apparently is
retained.
The relative distribution of Sr-90 in the plant end on
the outer surfaces may be quite variable, depending on the amount
of fallout end the type of sail.
The type of vegetation selected depends on whether it
represents food for animals or for humans.
For human foods the
semples can be taken from the consumer market.
The mealysis of
vegetetion is simpler than for soils or for fallout collections
since the amount of inactive material is small related to the
erount of Sr-90, and because the plant discriminates against many
of the redioective isotopes.
Analysis still requires, however,
separation of Sr~90 from the inactive constituents of the plant
esh and from other radioisotopes which are present.
Milk
The major source of body calcium in the United States is milk,
hence its enelysis has received considerably more ettention then
Ce