ISOLATION OF PLUTONIUM-BEARING PARTICLES FROM THE TEST SITE M. W. Nathans and E. Francisco LFE Environmental Analysis Laboratories Richmond, California ABSTRACT One hundred plutonium-bearing particles have been isolated from surfacesoil samples obtained from two locations each around five shot sites. These particles are analyzed by other laboratories by means of an electron microprobe, an ion microprobe, a scanning electron microscope, and by mass spectrometry. In this paper, the method of isolation is discussed and some observations with regard to the particles isolated are presented. INTRODUCTION The isolation of 100 plutonium-bearing fallout particles from the Nevada Test Site was undertaken by our laboratory last summer at the request of M. G. White, of ERDA's Nevada Operations Office. The purpose of this particle isolation project is to provide W. Efurd, of McClellan Central Laboratory of the U.S. Air Force, and L. Dietz, of Knolls Atomic Power Laboratory, with individual particles for analysis by scanning electron microscopy, mass spectrometry, electron microprobe analysis, and ion microprobe analysis. At the completion of the project, each of the two laboratories will have analyzed 50 particles. The results of Soil samples were received from five different sites, two samples from the analyses will be reported by the two laboratories independently. each site, for a total of 10 samples. The two samples from each site were such that one sample was obtained from a location about 100 feet from Ground Zero on the hot line, and the other sample from a location about 500 feet from Ground Zero on the hot line. Special samples were obtained by REECo personnel by careful scooping up of about 1 centimeter of topsoil. 537