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JOURNAL OF THE 4.0.4.C. (Vol. 42, No. 2, 1959)
Table 3. Average total beta radioactivity of miscellaneous foodstuffs
produced before and after 1945
Foodstuff
Wheat?
Sugar and jams?
Meat products
Bread?
Cocoa beans?
Misc. sea food*
Coffee4
No.
Before 1945
/m/g
s.e.(+)
No,
28
17
13
13
16
12
8
19
21
13
0.00
0.00
0.19
0.151
0.049
0.111
16
0.00
0.130
From 1945 to 1957 inel.
/m/2
g.e,(-)
0.01
0.03
0.00
0.00
0.33
G.00
0.00
0.087
0.005
0.125
0.119
0.234
0.196
0.874
® The unprocessed wheat grain.
.
> Includes sirup and a variety of fruit jama.
«Includes beef, pork, poultry, lamb: also dried and cured products.
4 Fresh: All 1957; no pre-1945 samples available.
* Includes shrimp, crab, lobster.
post-1945 over the pre-1945 samples is dem-
onstrated. Again it was noted from the raw
data that the preponderance of samples was
drawn from the years 1945 to 1950. Taking
the 107 samples originating from the year
1945 and comparing with 46 samples from
the years 1956 and 1957, the averages are as
follows: 1945, 0.05 d/m/g; and 1956 and
1957, 0.00 d/m/g. There is no trend toward
increased radioactivity in current samples.
Unfortunately, only a very limited number
of vegetables are represented by the leafy
variety, such as cabbage and lettuce; therefore, in the light of recent findings (3) further analyses must be conducted to confirm
present trends (1948 et seq.).
Table 3 lists results for a number of miscellaneous foodstuffs. No significant increase
in radioactivity is demonstrated for wheat,
sugar and jams, meat products, and miscellaneous sea foods. No pre-1945 samples of
bread, cocoa beans, and coffee were obtainable;
henee a comparison is not possible.
However, unless cocoa beans store some other
natural radioactive substance, it is possible
that this product reflects contamination from
fallout. Further work is necessary.
With respect to wheat which has been
shown to be radioactive in certain areas of
Minnesota in the growing years of 1956, 1957,
and 1958, it should be emphasized that prac-
tically all our post-1945 samples came from
the 1956 harvest. Of these, 16 samples originated from California, 3 from Texas, 2 from
New York, and one each from Indiana and
Michigan. This may account, therefore, for
our non-confirmation of increased contamination in this product to date.
The products which have shownsignificant
increases in radioactivity, or at least well
defined trends, are shown in Table 4. Of
these, the dairy products show a highly sig-
nificant increase in total radioactivity in the
post-1945 period. Tea shows an outstanding
increase. When plotted by years, the indi-
vidual values for the dairy products described
a line having a significant positive regression.
A similar plot for shellfish is shown in Fig. 1.
Identification studies on two samples of
tuna fish which exhibited marked elevation
in total radioactivity showed that the principal nuclide was zinc 65. Two samples of
tea, similarly studied, revealed the presence
of significant amounts of zirconium 95. These
analyses were made by gamma spectrometry
(4).
Two samples of tea showingrelatively high
total beta counts were subjected to radiochemical analyses (5).
Of the total beta
radioactivity in one sample, 6.7% and 45%
was accounted for, respectively, by total
Table 4. Foodstuffs which have shown
increased total radioactivity when
compared with pre-1945 samples
Foodstuff
Fish¢
Shellfish¢
Dairy products‘
Tea?
*
6
¢
4
Before 1945
No,
/m/zg
From 1945 to
1957 incl,
No.
d/m/g
25
15
0.00
0.00
26
32
0.322
0.364
36
0.00
&8
31.4
26
0.00
46
Includes mainly salmon, sardines, and tuna fish,
Significance level, p = 0.1.
Includes oysters, clams, and mussels.
Significance level, p = 0.1.
‘Includes fluid, dry milk, cheese,
f Significance level, p = 0.01.
? Tea leaves only, not the beverage.
0.55/