144 The various ratios of each radionuclice which were encountered had little effect on the computed range. As the tctal activity decreases, the 23° ~" U cnain radionucliuss becore increasingly important and the range changed regularly. Since the 238) decay chain members were not measured in every Tagoon samole, the total alpha concentration of each sample was initially estimated from equation 4 using an initial range of 4.584 mg/cm” , the mean of all measured lagoon sample ranges with concentrations greater than 70 pCi/g. If the concentration calculated was within the range 3.33 to 74.4 pCi/a, the better range of the alpha radiations in the sarnple was couputed using the initial concentration calculated and the range-activity relation from Appendix Fig. 3, which is mathematically expressed by: ty Ro_ fess _ (pCi/g 74.4)° é + 4.23 (5) 200.8 wonere: Ry = new range in mg/cn’ pCi/y = activity comautea using 4.548 ng/eme in equation 4 The new range is reinserted into equation 4 and the concentration in pCi/g is recalculated. If the activity was less than 3.33 pCi/g, 4.23 mg/cm was used as the rance. Only one reiteration of the cycle is necessary. Tne activities obtained by this method are shown irc Appendix table 2, column &. The activities from direct measuremants are shewn in colunn C for comparison. One can see that the rapid technique gives values that ere about