FIGURE 6-22, SURFACE SOIL REMOVAL FROM ISLAND PEARL. Soil was pushed into windrows, then hauled to a stockpile, at lower left, to await transport to Yvonne, Only a small area near right center required more than onesoil “lift.” View is almost due east. (June 1979) Fortunately, from a time standpoint, the situation faced was different in several respects from the situation of earlier GZ investigations. The early explorations were searching for suspected burial sites based on limited prior knowledge: results in NVO-140 were from sampling pits of various depths, the pits were located in a quasi-random pattern, and the TRU/241 am ratio was unknown or only approximate. In the current case, the FPDB profile pits were of uniform depth, were located at the nodes of a 50-m grid, the TRU/24! Amratio was known with fair confidence, and the depth of the zone bearing high TRU concentration was indicated by the FPDB sampling results. A TRU value greater than 160 pCi/g in any FPDB sample was cause for further investigation. Sampling results from the eight grid nodes nearest the culprit could be examined for indications of the direction and areal extent of the pocket of contamination. Each node on a 50-m grid represented a quarter hectare, but excision criteria were based on 191 the average concentration in an area of