— 2N APPROXIMATE SHORELINE ———-~_——___» PEARL LEGEND * = 50M GAID STAKE NOT SAMPLED 1= AUGERED PROFILE LOCATION (33) Op x = SURFACE, 10 AND 20 CM COMPOSITES (10) > NUCLEAR TEST GROUND ZEAO - SIDEWALL PROFILE LOCATION (15) METERS FIGURE 6-19. SUBSURFACE SAMPLING LOCATIONS ON ISLAND PEARL PRIOR TO 25 APRIL 1978 Apparent Anomalies. NVO-140 identified a number of suspected burial sites for radioactive soil or debris. The suspected sites on Janet and Pearl were identified based on the assumption that activated metal, and possibly soil, would be present around a surface ground zero following the nuclear test, and that disposition by burial in the area might have occurred. Subsurface investigation in the vicinity of the Item GZ failed to locate any activated debris and TRU concentrations in the soil were below excision criteria, No verifiable explanation has surfaced to account for this apparent anomaly; however, two possibilities have been offered. First, the topography in the vicinity of the Item GZ has changed significantly since the test, with substantial erosion of the northern tip of Janet; contaminated soil could have been eroded from its burial site and redeposited in diluted form elsewhere. Second, a gravel quarry was located on the northern tip of Janet so buried metal debris could have been unearthed and pushed aside, then treated as contaminated surface debris. Subsurface investigation and debris removal in the vicinity of the Inca GZ on Pearl were conducted in a sequence yielding less than desirable results. A significant volume of contaminated debris was encountered during lane clearing operations. As soon as the initial IMP gamma survey was completed, and prior to any subsurface sampling, the Army began debris removal. Many long "I" and "H" beams were unearthed with substantial churning of soil in a large area surrounding the GZ and extending southeast toward the lagoon (around stake location 5-S-3). By the time subsurface Sampling began, it was impossible to establish an accurate reference to the original surface and any pockets of high TRU concentrations had been churned and dispersed, possibly raising the average concentration of the new soil surface. When surface soil was removed from Pearl in 1979 (Figure 6-22), most of the churned area required removal of only one 15-em layer. No satisfactory explanation has surfaced to account for the relatively high TRU activity localized in the vicinity of Stake 5-S-3, about 270 meters from the Inca GZ, 188