RESULTS AND DISCUSSION Daily Activity Ingestion Rates Daily activity ingestion rates were calculated for dosimetrically signi! icant nuclides post return. An exponential decline was proposed for the inges~ tion rate within a population subgroup and initial reference values are giver in Figures 10 through 14 (June 1, 1957, was assigned as a return date to Rongelap). Figure 10 demonstrates the differences in ingestion of L37e, for various populsation subgroups. This undulating pattern was exhibited by 1370,, 905., and Orn, nuclides for which sufficient data existed for analysis. Differences in ingestion rates of the stable element at the same geo- graphic location have been shown to occur among wembers of a popylation (ICR! 23). Age dependent diet studies for ingestion of Cs for urban’ Japan have values varying from 11 yg a7? for adults to 8.6 ug a7)tor childreg,| Sr: in a western oe a : type diet rose from 600 yg d 1 tor infants to 690 ug avi for 5 year olds to 3,600 yg a7) for 13 year olds and fell to a mean of 1,900 usd”tor adults. 2n in the United Kingdom rose from 2 to 40 mg d™!, the higher value of Zn being Fe ingestion in a western type diet has a mini~ the Marshall Islands Diet and Living Pattern Study (Ne80) observed coconut si) being used as a major food supplement for infants, and later in adult life as major gource of daily fluid intake. Since coconuts and coconut tree sap pro- vided the major source of 1376, on Bikini Atoll (Le80, Mi80), the shape of Fig ure 10 was in agreement with the observed diet pattern. 22 i: Sout te The authors of .- population also exhibits dietary changes as a function of age. The Marshallere . ug a? for Japanese adults and half this amount for children. 4z ' na fi oe tray te OES yi odes oie arn bee , 3x" 3 Co is ingested at a rate of 20 etalon pie ate umn ceahastaltethat hecanaae aculeealScat Sisare mum at age 3 and maxima at ages 1 and 20 years. canadian observed in adult tea drinkers.