the In July, 1972, by a request from Nevada Operations Office (ERDA) to LASL, g retainin Element, Soils Soil Sampling and Analyses Committee was changed to the In Note: s (Editor' the chairman of the former as Manager of the new Element. nal management operatio e effectiv most the that ed determin was it 1976, spring, unit of NAEG studies had been that of principal investigator, plus co-investigators as necessary, for specific NAEG environment studies. At that time, the "elements" of the Nevada Applied Ecology Group were dissolved, with notification to the former program element managers involved.) Since that date, the Soils Element activities included (1) development of special sampling methods such as for mounds, (2) development of analytical methods, (3) quality assurance studies, (4) consultations relative to site selection, and definition of related missions and experimental design, (5) assistance to the statistician in the interpretation of data, (6) preparation of reports, including annual progress reports, (7) analysis of routine samples as a contributing laboratory, and (8) assignment as referee laboratory for NAEG soil samples. SOIL SAMPLING AND ANALYSIS METHODS The sampling methods used at NTS were developed as modifications of the trench method for sampling of profiles and of Alexander's "cookie cutter" method (Alexander et aZ., 1960) for sampling surface soils. Both methods were success~ fully tested on the Area 13 microplot; they were applicable to sandy or loamy soils where stones or highly cemented soil horizons did not present a problem. More recently, areas other than Area 13 have been sampled using the above techniques with no difficulty. Microplot Study The microplot study was initiated to test (1) proposed surface sampling methods, (2) proposed profile sampling methods, (3) proposed field radiation measurement methods with the FIDLER instrument (FIDLER--field instrument for the detection of low-energy radiation), and (4) proposed methods for sampling matrices other than soils. A microplot area 3.7 x 2.5 meters was selected at random approximately 250 m west of Area 13, Project 57 ground zero. The plot was covered by a structure to minify movement of soil by wind into and out of the plot. Before soil samples were collected, shrubs were removed by cutting at ground level and the microtopography was mapped. The plot was laid out in a grid pattern and the level of radioactivity of each grid section was determined by readings taken with a FIDLER instrument. (1) Three different FIDLER geometries were investigated: 30.5 cm lead collimator, (2) 15.3 cm lead collimator, and (3) detector placed on a sampling ring at 2.5 cm above the soil surface. The collimator seriously degraded the spectrum and its use was discontinued for determination of inventories. At the time of the microplot study, the FIDLER instrument represented the state of the art for survey instruments. The FIDLER [and Ge(Li) spectrometer] data are based on the 60 keV 2+!am gamma emission. The 24lam is the daughter product of 241py present in plutonium nuclear fuels, and plutonium concentrations can be estimated from those data if the 24!Am to plutonium ratio in the sample is known. 19