Been us a
STRONTIUM-90 IN MILK
ation are
different
as receive
west level
‘ed States
ulk prod1 is about
consumed
is largely
ignorance
‘ted away
nereasing
‘h in milk
diserimiit dietary
: indicate
nst Sr-90
own that
y in this
TABLE 6
Radiation received by humans from various sources
Source
External radiation:
Background—granitie rock
Sea level
‘oach two
- the rat,
h higher
‘ humans
a limited
cinomas;
non the
diet and
etual obrsons of
. Again,
asons for
al. (5,6,
iown. It
and that
that the
mination
yn agent
humans,
Equivalent
sunshine
units
Reference
147
(13)
10,000 ft.
230
(13)
Sea level
5,000 ft.
10,000 ft.
80
103
163
(13)
(13)
(13)
5,000 ft.
Background—sedimentary rock
Background—open oceans
Wrist watch
X-ray (routine chest)
X-ray (anterior-posterior body)
X-ray (lateral body)
Brick house
Earth fallout from nuclear deto-
nations in 1956
Soft tissue internal radiation :*
Potassium-40
Radium
Carbon-14
Cesium-137
Equivalent internal bone radiation :°
Radium
Potassium-40
Cosmic rays—Sealevel
such as
are even
discrimi-
Milliroentgens
per yr.
Strontium-90*
5,000 ft.
10,000 ft.
170
57
10-40
500~2,000
3,000
7,000
(14)
1-5
(14, 199}
19
(13)
2
1.5
(199)
(13)
1
(199)
6.7, 120
2.2, 40
37
12
5
60
112
L5
Adults
0.6
In 10 yr. if testing stops now:
Children
If testing continues :4
(13)
(13, 19g)
(19g)
(13)
(13)
25-50
Now (1957-8):
Children
Adults
(13)
4.8
1.2
12-63
17
(13,14)
(19g)
(14)
20
37
(14)
(19g)
0.5
(14)
1.6
(it)
0.2
0.4
4-21
(11)
(11)
(11,14)
*In addition to external radiation, much of which penetrates tissue.
» External radiation (chiefly y) other than cosmic rays also is active at the bone level.
It is difficult to assess the proportion that actually is. Dudley and Evans (19d) assume that
about 70% of the radiation from the ground rocks is effective at the skeletal level.
* Eckelman et al. (8) estimate that the standard deviation for Sr-90 in individual persons
wil] be about 40% of the mean at equilibrium.
“Value at 50 yr. if testing continued at same rate with same type devices as past 5 yr.
New Sr-90 entering atmosphere is in equilibrium with that falling out.
such as cheese, cultured milks, etc., contain a negligible amount of lactose.
Furthermore, milk and milk products are generally consumed in conjunction
with other foods, where the effect may be minimized.
The immediate need for further investigations in this area is apparent. Conclusive data are needed concerning the discrimination against Sr-90 in humans
on a milk diet and concerning the effect of specific dairy products. If it is true
that certain dairy products, or the way in which they are consumed, do not allow
the gut to discriminate as well against Sr-90, then it would be preferable if
the dairy industry itself would find out the facts about them. It would be undesirable to let someone else not directly concerned with the industry throw a
{11 ]