RESULTS AND DISCUSSION
Daily Activity Ingestion Rates
Daily activity ingescion rates were calculated for dosimetrically signifi-
cant nuclides post return.
An exponential decline was proposed for the inges-
tion rate within a population subgroup and initial reference values are given in
Figures 10 through 14 (June 1, 1957, was assigned as a return date to Rongelap).
Figure 10 demonstrates the differences in ingestion of 137,, for various population subgroups.
This undulating pattern was exhibited by
137,
s,
90
Sr, and Ooo n,
nuclides for which sufficient data existed for analysis.
Differences in ingestion rates of the etable element at the same geographic location have been shown to occur among members of a population (ICRP
23).
Age dependent diet studies for ingestion of Cs for urban Japan have values
varying from 11 ug a? for adults to 8.6 Lg a7 for children.
Sr in a western
type diet rose from 600 yg a7 for infants to 690 ug av! for 5 year olds to
3,600 ug at for 13 year olds and fell to a mean of 1,900 pg a) for adults. Zn
in the United Kingdom rose from 2 to 40 mg at, the higher value of Zn being
observed in adult tea drinkers.
Fe ingestion in a western type diet has a mini-
mum at age 3 and maxima at ages 1 and 20 years.
Co is ingested at a rate of 20
ug at for Japanese adults and half this amount for children.
population also exhibits dietary changes as a function of age.
The Marshallese
The authors of
the Marshall Islands Diet and Living Pattern Study (Na80) observed coconut sap
being used as a major food supplement for infants, and later in adult life eas a
major source of daily fluid intake.
Since coconuts and coconut tree sap pro-
vided the major source of 1376, on Bikini Atoll (Le80, Mi8Q), the shape of Fig~
ure 10 was in agreement with the observed diet pattern.
22