METHODS Soil samples were taken at predetermined locations for each event site. In general, the locations were the intercept points of a 200-foot by 200-foot grid surveyed from the ground zero point of each event site. In the immediate vicinity of ground zero for the Hamilton, Small Boy, and BFa sites of Area 5, and for the T-1 site of Area 1, additional locations were chosen using a In addition to these locations, samples were also taken at two 100-foot grid. random points within each 200-foot by 200-foot grid square of the Hamilton site. The majority of sample locations were sampled at five different depths: the surface, 30, 60, 90, and 120 cm. Each location was at least sampled at the Sampling was accomplished by first digging a 24-inch wide by 4-foot surface. Then a 10 cm long by 10 cm wide deep by 6-foot long trench using a backhoe. by 5 cm deep sampling tool was used to remove the soil samples of interest. A selected number of these samples were dried, weighed, ball-milled, and a 10 g aliquot used for wet chemistry analysis for plutonium. samples were Ge(Li) scanned for 100 minutes. All of the soil A more detailed description of the sampling and analysis methods used in this program is given in the Nevada Applied Ecology Group Progress Report NVO-153, June, 1975. DATA DISCUSSION Table 1 lists the sampling grid size, the number of sample locations, and the number of soil samples taken from each site in the areas sampled to date. It also lists for each site the number of plutonium concentrations determined by wet chemistry, as well as the number of plutonium concentrations which can be inferred from Ge(Li) counting Am-241 and the number of concentrations of the three most significant gamma-emitting radionuclides. Plutonium concentrations were determined for each sample taken from the Hamilton site of Area 5. Since two different sample location systems (grid system and random system) were used for the Hamilton site, there are two sets of plutonium concentration data for this site. This should allow both estimates of inventory and distribution, and estimates of their respective errors to be made. The data from the Airdrop site and Able site of Area 5 contain so few plutonium concentration numbers that no plutonium distribution can possibly be estimated. However, an upper limit to the plutonium inventory for these sites can be estimated, if it becomes necessary to use these limited data. 234 fa