DETERMINATION OF THE PLUTONIUM TO AMERICIUM RATIO IN SOIL SAMPLES FROM ISLAND IRENE DOE/ERSP TECH NOTE NO. 2.1 DATED: 21 November 1977 AUTHOR: B. Friesen, DRI Reference Tech Note 2.0 for introductory remarks. Soil samples were collected from the surface and from 10 em and 20 cm depths at 5 locations on the island of Irene. Results from the laboratory showed high variation in the 238,239,240py to 24lam ratio, with the lowest values west end. One intermediate value was approximation estimates of total Pu below. Soil sample locations and the which this Tech Note is appended.* on the east end of the island and the highest values on the observed in the north central portion. In order to derive first distribution, three separate ratios were used and are shown areas for which each ratio apply are shown on the map to "A" Samples Ratio No. 1 3 5 7 9 "B" Samples Ratio Ratio No. Ratio 2.85 4.67 9.43 9,21 12.45 2 4 6 8 10 2.54 5.64 11.63 7.59 10.60 Ratio Numbers 1-2 3-4 5-10 Simple Mean Weighted Ratio Used 2.70 5.18 10.28 3.0 + 0.72 6.0 + 0.60 11.0 + 1.60 2.70 5.16 10.15 ADDENDUM TO TECH NOTE2.1: DETERMINATION OF THE RATIO OF TOTAL TRANSURANICS TO AMERICIUM IN SOIL ON ISLAND IRENE DOE/ERSP TECH NOTE NO.2,1-A DATED: 6 February 1978 AUTHOR: M. Barnes, DRI For the purpose of computing values of total transuranies from americium values, Irene was divided into three distinct areas as described in Tech Note 2.1. In each area, using 0, 10, and 20 em soil sample results, the simple mean and standard deviations of the ratios were computed.** These values were then used in estimating quarter hectare average concentrations of total transuranies. Area Eastern End Central Area Western End TRU/Am 4.12 6.50 11.13 Standard Deviation 0.53 1.20 1.70 *Map omitted here. **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-2-8