Table 9. Theintegral 30-, 50-, and 70-y dose equivalents for bone marrow and bone surfaces for intake of
20Sr beginningat various ages.
Age intake begins
Birth
Bone marrow
30 y
50 y
70y
41.4
62.0
Integral dose equivalent, mrem
Bone surface
30 y
50 y
70 y
30 y
Effective
30 y
70 y
75.0
122
182
223
8.6
12.9
15.7
15.8
4 months
41.7
62.5
75.6
123
184
224
8.7
13.0
9 months
43.1
63.7
76.6
127
187
227
9.0
13.3
16.0
1.5 y
43.8
64.3
77.1
129
189
229
9.1
13.4
. 16.1
4y
43.2
64.0
77.0
126
187
228
9.0
13.3
16.1
12 y
49.3
70.4
83.5
137
199
241
10.0
14.4
17.3
18 y
48.5
69.8
82.9
116
175
217
9.3
13.6
16.5
Table 10. The integral 30-, 50-, and 70-y effective dose equivalent for continuous intake of 137Cs and
90Sr beginningat various ages.
Integral effective dose equivalent,
mrem@
Fraction due to Sr
Age intake begins
30 y
50 y
70 y
30 y
50 y
70y
Birth
4 months
386
398
580 592
702
714
0.02
0.02
0.02
0.02
0.02
0.02 ©
9 months
367
560
683
0.03
0.02
0.02
iSy
370
564
687
0.03
0.02
0.02
4y
391
585
708
0.02
0.02
0.02
12 y
469
663
786
0.02
0.02
0.02
18 y
513
705
829
0.02
0.02
0.02
*
* The effective dose equivalent is a unit defined by the ICRP (1984) which allows for the different
mortality risks associated with irradiation of different organs, together with a proportion of the
hereditary effects.
ye
-eur
fo &
a
Discussion
The result of our analysis is that the
reason is the consistently higher intake of local —
integral 30-, 50-, and 70-y effective dose
foods, and thus !37Cs , for adults found in the
equivalent estimated for intake beginning as
diet surveys from the Marshall Islands.
that for intake beginning at any other age.
Consequently, the estimated integral dose
equivalent for adults is a conservative estimate
for infants and children. There are two basic
reasons for this result. The first, and major,
supported by diet surveys of other societies; the
intake for adults is greater than for infants and
children.
The second reasonis that even for continuous
137Cs intake that declines at a rate equal to the
adults at a contaminated atoll is greater than
3
LZS5
3008254
Also,
the higher intake of food in general by adultsis
1