pene tem Ba sot ie 1 ~26- radioactive Ftne shore birds contained greater amounts of tissues shortly after the prisls in the different organs and A similar tendency was Rout at Rongelap than did the terns. » in 1952 at Eniwetok WL-33)). following Mike shot (see WT-616 However, the average levels of activity in the ans of the shore birds decreased more rapidly with increasing . after fallout than did those of the terns. These differ- les may be accounted for, in part at least, by the differences feeding habits and migrational characteristics. | Rongelap terns are given in Table V. With the exception of bs he och icin ies ge ee pee ie ci aa is ena Slat er < The average specific activities of the organs and tissues scle, which is consistently low compared with the other Bsues, there is no distinct pattern of relative activities eween different organs. | The decline of radioactivity levels in the organs and psues of terns may be divided into three types (Figures 10a : b): (1) organs in which the decline is semilogarithmic, Bf-life 40 days-- these include the muscle, liver, and pny; (2) organs in which the decline is logarithmic -~ these the bone (r = t7£+35) and ileum (r = t72-85), and (3) organs which the vartability is extremely great -- the skin and lung present this group. } The shapes of the radioactivity decline curves for the pferent organs are determined by @ combination of (1) avail- Llity of the isotopes, (2) total uptake and degree of selec- ye uptake of different tsotopes, (3) radioactive halflife, (4) biological half-life. Since the relative effects and floblological Studies . . . op. cit., p. 6. oO

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