142 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



trace-element concentrations in aerosols from 104 published and unpublished data sets 

 were used to calculate enrichment factors. From the enrichment factors in each data set, 

 the geometric mean enrichment factor (EFg) and geometric standard deviation (Sg) of the 

 logarithmic frequency distributions of enrichment factors were calculated for each 

 element by the following formulas: 



N 



EFg = exp(^^lnEFi) (A.4) 



and 



Sg = exp 



where N is the number of data points and EFj is the enrichment factor of the \th point. 



The geometric mean enrichment factors obtained by Rahn (1976) for 19 elements are 

 given in Table A.l for global, remote marine, remote continental, and urban aerosols. The 

 geometric means of the global aerosol enrichment factors include data from all points and 

 may be weighted too heavily toward cities, but they can serve as a useful first 

 approximation to a general aerosol. The urban enrichment factors are geometric means 

 for 29 cities. The enrichment factors for remote continental and remote marine areas 

 were read from the enrichment-factor plots and are therefore somewhat subjective. 



Values for EFg/sg and EFg X Sg, respectively, were calculated with the use of global 

 values to obtain the lower and upper limits for 68.27% of the enrichment factors closest 

 to the geometric mean. (When describing concentrations at selected statistical levels 

 remote from a mean, the Sg is a multiplier or divider of the EFg, whereas its counterpart, 

 Gaussian standard deviation, functions as an increment to the arithmetic mean. This is a 

 consequence of the fact that multiplying and dividing values are equivalent to adding and 

 subtracting their logarithms.) The results from these calculations are also given in 

 Table A.l. 



References 



Andersen, B. V., 1964, Plutonium Aerosol Particle Size Distributions in Room A.u, Health Phys., 10: 



899-907. 

 Armstrong, John T., and Peter R. Buseck, 1975, Quantitative Chemical Analysis of Individual 



Microparticles Using the Electron Microprobe: Theoretical, /l«fl/. Chem, 47: 2178-2192. 

 Axtmann, R. C, L. A. Heinrich, R. C. Robinson, O. A. Towler, and J. W. Wade, 1953, Initial 



Operation of the Standard Pile, USAEC Report DP-32, E. I. du Pont de Nemours and Co., 



Savannah River Laboratory, NTIS. 

 Boyd, George A., 1955, Autoradiography in Biology and Medicine, Academic Press, Inc., New York. 

 Duce, Robert A., Gerald L. Hoffman, and William H. Zoller, 1975, Atmospheric Trace Metals at 



Remote Northern and Southern Hemisphere Sites: Pollution or Natural? Science, 187: 59. 

 Eastman Kodak Company, 1916, Kodak Materials for Nuclear Physics and Autoradiography, Kodak 



Technical Pamphlet No. P-64. 

 Elder, John C, Manuel Gonzales, and Hairy J. Ettinger, 1974, Plutonium Aerosol Size Characteristics, 



Health Phys., 27:45-53. 

 Ettinger, Harry J., William D. Moss, and Lamar J. Johnson, 1971, Size Selective Sampling for 



?lutomum-23S, Health Phys., 23: 41-46. 

 Fleischer, Robert L., and Otto G. Raabe, 1977, Fragmentation of Respirable PuO^ Particles in Water 



by Alpha Decay — A Mode of Dissolution, Health Phys., 32: 253-257. 



