N-10
INHALATION DOSE
The inhalation of dust can vary tremendously depending on activity.
On Bikini Island ploughing an open field in the dry season would
represent the high end of the spectrum: resting quietly at home or
Sailing on the lagoon would be near the low end. Robison (Ref. UCRL
53805, p. 9) has revised his earlier excessive estimate based on 5 hours
per day of ploughing. As an average now throughout the year, he takes 1
hour per day plus 23 hours under normal conditions, resulting in a daily
intake at Bikini of .017 pci of plutonium-239,-240 and .0071 pCi/d of
americium-241, totalling .024 pCi/d.
To obtain the Rongelap dose, it was assumed that the distribution of
particle sizes and of radionuclides was practically the same on Bikini
and Rongelap Islands. Therefore, the inhalation dose on Rongelap would
be to that on Bikini as the transuranic specific activity of Rongelap
soil (0-5 cm) was to that of Bikini Island. The plutonium level on
Rongelap was 29% of that on Bikini, and the americium level 12% (Robison
1982a, pp. 8, 12, 44, 56; 1982b, pp. 12, 14, 47, B10, B13).
The daily transuranic exposures for adults on Rongelap were
therefore:
plutonium-239,-240,
anericium-241,
Total
29% of .017 pci
= .005 pci/d
12% of .00071 pCi = .0009 pCi/d
-006 pCci/d
-The adult 30-year inhalation doses are estimated to be
(Table 4.2 #1B):
Tissue
Plutonium-239 ,-240
(rem)
Americium-241
(rem)
Whole-body
023
004
Red marrow
035
-006
Bone surfaces
-004
-0007
For the infant (to be on the safe side) we have assumed exposure to
be the same as for an adult. Therefore, taking the total daily
transuranic exposure as .006 pCi/d, we find the whole-body dose for the
first year to be (Table 4.4 #1):
9000618
—