7.5.4 Sally Background Island Sally (Marshallese: Aomon)is the largest of the northeast islands in the Atoll with an area of 40 hectares (ha). It is the northernmostisland in the Sally-Tilda-Ursula chain; these three islands are connected by eauseways. The island is triangular in shape with sandy soil and heavy vegetation on the northern half of the island. The southern half of Sally is clear of vegetation and extremely sandy. On the western sidé of the island, a slender point of land juts out as a result of activities that took place.after the testing program. Sally and the island Ruby were once connected by a land causeway but due to two nuclear events on Ruby, only two small parts of Ruby remained. One of these parts was still connected to Sally by the causeway and in 1972, a tidal pond beside the causeway wasfilled in during the Pacifie Cratering Experiments (PACE). (See Section 1.5.2 for more information on PACE). This western tip, called Cape Mixan throughout the cleanup project, is considered part of Island Sally even though it was once part of Ruby. The second part is now a separate isle referred to as Ruby (see Section 7.4.9). Sally was the site of three nuclear tests, all on towers. As Figure 7-97 indicates, one ground zero (GZ), Kickapoo, was located on the northern tip and the other two GZ's, Yoke and Yuma, were located on the lagoon side of the island. Because of these three tests, plus fallout from 13 other events, Sally ranks 13th in the Atoll in total H + 1 hour exposure rate with 1,981 R/h. One test bunker used for several operations remains on Sally and is located on the northwest ocean side of the island near the bend where Cape Mixan connects with the main body of the island. Other remnants from the testing years included several concrete slabs and blocks, a gamma shelter and a number of coaxial cable runs. The anchor blocks located around the GZ's were suspected to have some radioactive contamination underneath an added layer of uncontaminated concrete. Both suspected and known plutonium burial sites existed on Sally prior to cleanup. The most obvious burial site, called the Aomon Crypt, was located on the manmade causeway connecting Sally and Tilda. The site was marked by a 6 inch square concrete post at each corner and a plaque stating that plutonium contaminated debris and soil were buried in that area. The characterization and cleanup of this burial site was a major part of the project and is discussed more fully in Section 6.8. Other suspected areas of subsurface contamination were the three event sites because burial of radioactive material was done routinely at or near the GZ's. The landfilled causeway between Sally and Ruby was also a suspect area because some of the fill was soil from the Yuma GZ. 1972 Survey In 1972, soil samples were collected at 28 different sites on Sally along with some vegetation and animal samples. Except for two 0-15 em core samples collected from the beach of the filled causeway between Sally and Ruby, all the soil samples were collected outside the PACE area. Out of the 28 samples, 20 were 0-15 em core samples and 8 were profile samples down to a maximum depth of 200 cm. Two of the soil sample profile results showed the 239%240py, 90sr, and 137Cs activities to be increasing to a depth of 60-150 em below the surface, while another profile showed almost homogeneous activities to a depth of 40 em. These unusual distributions could be attributed to soil disturbance caused by a combination of post-shot activities around the event sites and the PACE operation. Other profiles showed the expected rapid decrease in activities with depth through the first 20 em, with the rate of decrease leveling off below 20 em. The highest concentrations for the radionuclides, 239,240 py, 90sp, and 137 Cs, were found on the lagoon side of the western tip. Tables 7-1, 7-2, and 7-3 show the 0-15 em island means and ranges for 137¢Cs, 90sr and 2 9,240py, respectively, for the 1972 survey data. 320