mANSUHANIC ELEMENTS IN ARCTIC TUNDRA ECOSYSTEMS 455 



Highest values were found in samples taken during early 1965; values then declined to 

 to 04 tri ^^^•^'*^Pu/g (dry weight) and to 0.1 fCi "^Pu/g. A relatively constant 

 isotopic ratio of 1/4 (^^^Pu/^-'^'^'*°Pu) prevailed throughout the sample series analyzed. 

 There was little or no correlation between plutonium and ^^^Cs concentrations in flesh 

 On a seasonal basis, and '^^Cs concentrations were generally 2.5 x 10^ times as great as 

 2 3 9,2 4op|^j concentrations. Concentrations of ^"^^Am in 35 of the preceding flesh 

 samples were of the same general values as the plutonium concentrations but were often 

 more variable. 



Radionuclides in Carnivore T^issues 



A limited number of carnivore tissues have thus far been analyzed for their transuranic 

 nuclide content. The results were so variable and near the minimal detectable amounts of 

 radionuclides that larger sample volumes (up to 100 g of ash) of most mammalian species 

 were analyzed to provide more positive values for meaningful comparison and 

 interpretation. The results (Table 11) showed that (1) only 2 3 9,2 4 0pjj (.Q^l^J ]jq reliably 



TABLE 11 Concentrations of^3^Pu,"''-^'*°Pu, and '* ^ Am in Large 



(38- to 100-g ash) Muscle and Bone Samples Composited from Several Animals 



Collected at Anaktuvuk Pass, Alaska, During April and May 1976 



* Number of animals. 



fMean ± standard error (counting statistics). 



reported from these composited animal samples. (2) caribou tlesh contained slightly 

 higher 2 3 9,24 0p|j concentrations than wolf and fox flesh, and (3) there was no indication 

 of biomagnification in the upper trophic levels of the food web. Concentration ratios of 

 the plutonium isotopes were generally similar; the lichen/soil ratio was 140—180; the 

 caribou/hchen flesh ratio was 0.004-0.005; and the wolf/caribou ratio was 0-0.9. 



Conclusions 



Two major periods of worldwide fallout deposition on northern Alaskan and Greenland 

 ecosystems have occurred as a result of atmospheric nuclear weapons tests of Great 



