CALENDAR YEAR 1975 STATUS: NEVADA APPLIED ECOLOGY GROUP DISTRIBUTION AND INVENTORY SAMPLING DATA F. R. Markwell and B. W. Church Nevada Operations Office, Las Vegas U.S. Energy Research and Development Administration ABSTRACT To date, under this program over 6,000 soil samples have been taken from Areas 1, 4, and 5 of the Nevada Test Site. All of these samples were Ge(Li) scanned for Am-241 and other gamma-emitting radionuclides by Reynolds Electrical & Engineering Co., Inc. (REECo), and the results indicate only about 5% contained Am-241 in quantities above the detection limit (1 pCi/g of Am-241). In addition, approximately 10% of the samples were subjected to wet chemistry analysis for Pu-239 by REECo. The results indicate all contained Pu-239 in quantities The largest concentrations above the detection limit (0.01 pCi/g of Pu-239). of Am-241 and Pu-239 appear in the Hamilton and Small Boy sites of Area 5. The Hamilton soil data may be sufficient to estimate both an inventory and a distribution for plutonium over most of the site, but the data from the majority of the other sites are sufficient only to set upper limits of plutonium inven- Extensive additional soil sampling and/or analysis will likely be tories. required before estimates of plutonium inventories and distribution can be made for these sites. INTRODUCTION The Nevada Applied Ecology Group (NAEG) Distribution and Inventory Program's soil sampling program intensified in late 1974, and has continued to date. Over 6,000 soil samples from Areas 1, 4, and 5 have been analyzed. Wet chemistry analysis for plutonium has been used on some of these samples, while Ge(Li) scanning to infer plutonium concentration has been used for all. The inferred method is several orders of magnitude less sensitive than the wet chemistry analysis, and as a result, the inferred method for most samples can only be used to determine an upper limit of plutonium concentration. 233