TRANSURANIC ELEMENTS IN ARCTIC TUNDRA ECOSYSTEMS 451 



TABLE 5 Worldwide Fallout ' ^ ''Cs Inventory* 



in the Cladonia-Cetraria Lichen Carpet at 



Long-Term Sampling Sites Near Anaktuvuk Pass, 



Alaska, During the Period 1962 to 1976 



*Vaiues are based on samples of 0.25-m^ to 0.5-m^ 

 replicates from contiguous sampling areas. 



t Number of samples. 



$Mean ± standard error. 



§Cumulative fallout deposition at Anaktuvuk Pass 

 between successive sampling periods based on 0.67 of 

 monthly measurement at 1 airbanks (Hardy, 1975). 



very sliglit because the decline occurred in both lichen communities sampled and the 

 analytical data have been verified. One-way ANOVA tests performed on untransformed 

 and log-transformed lichen radionuclide data for the years 1974 to 1976 showed 

 significant (P<0.05) differences between 1974 and 1975 and between 1975 and 1976 

 which were identified by multicomparison procedures. These differences were confirmed 

 by such nonparametric procedures as the Kruskal— Wallis and Kolmogorov— Smirnov tests 

 (Hollander and Wolfe, 1973). The ^^^•^'^^Pu/^ ^ ^Cs ratios in Alaskan lichens usually 

 were stable near 0.013, but they decreased to 0.006 during 1975. Statistical analysis (t 

 statistic for two means) of the 1971 to 1976 plutonium concentrations (Table 7) revealed 

 that the 1975 values were significantly lower than the other years and that the 

 2 3 8pjj^2 3 9.2 4 0pjj ra^JQg j^i the Alectona-Claclonia-Cetraria lichen community samples 

 during 1976 were significantly greater than those in the Cladonia-Cetraria community 

 samples. 



During 1969 and 1970 the Cladonia-Cetraria lichen carpet samples were fractionated 

 into upper 6-cm (Cu) and lower 6-cm iC\) components to test the hypothesis that there 

 were no significant differences between their radionuclide concentrations (Hq : Cy = Ci) 



