DETERMINATION OF THE RATIO OF TOTAL TRANSURANICS TO AMERICIUM IN SOIL ON ISLAND SALLY DOE/ERSP TECH NOTE NO.2.5 DATED: 25 January 1978 AUTHOR: M. Barnes, DRI A total of 51 soil samples from 9 locations on Sally were analyzed in the laboratory for 238,239,240py and 2414m. Fourteen of the samples had americium concentrations less than the lowest detectable level, hence were not usable for ratio computations. The PACE excavation activities affected a large portion, but not all, of the island. The assumption was made that all areas of the island that were affected, either by being excavated or by having new material piled on top, had ratios of total transuranics to americium from a single population, The remaining small areas, one in the vicinity of Kickapoo ground zero and one in the vicinity of Yuma ground zero, were each considered to have a separate ratio. The area of Yoke ground zero was excavated during PACE operations and was considered as part of the affected area. All usable samples, listed below, were considered in calculating simple mean ratios and standard deviations. Sample locations 14-S-8 and 12-S-4 had all depths and both composites with americium concentrations less than lowest detectable level so were unusable. Boundaries between ground zero areas and PACE-affected areas were based on the 1972 aerial photographs and the IMP survey measurements. Depth, em Location 0 WA tt 26-N-12 28-S-2 14-S-10 24-N-10 2-N-2 18-N-4 20-S-4 7.34 3.01 2.43 4.86 3.55 4.47 3.49 10 im 3.79 2.45 9.19 4.45 3.78 2.90 3.46 trAtN 5.37 2.54 2.99 + * 3.42 * 20 "wan d.21 3.03 2.19 3.98 1.65 2.47 6.12 nA" 9,01 3.36 4.33 * 4.00 4.40 1.22 "Bt 4,22 3.44 2.43 * 1.82 2.75 2.67 The mean ratios and standard deviations** were used to derive estimates of quarter hectare average concentrations of total transuranics. Area Mean Ratio Standard Deviation Yume GZ 3.86 2.72 Rest of Island 3.37 1.08 Kickapoo GZ 6.16 1.73 *Americium concentrations were less than lowest detectable level. **This method of estimating the ratio and error was later replaced by a method based on more accurate assumptions as described in Tech Note 2.2-A, B~2-14