rp epee aera ee, = : ln 7 AECD-3446 -30Section Iv LAND SURVEY by A. H. Seymour and P. J. Kellogg Land surveys were made near the collecting stations and the ext ent of the The general plan wag survey was determined by the amount of radiation detected, to monitor the beach sand, drift items, the land, and vegetation in the same general BE area that specimens were being collected, : When the counts were about 60 per minute or less the actual values were determined by counting for one minute with a stop watch. Instruments used included two makes of GM counters - a Victoreen Model 263 A and a Beckman Model MX-5, and an ionization-type counting chamber, - a Victoreen-made Juno. Readings were made both with and without shields but unless . indicated the values reported are those of the GM counters without the shield. i.e, beta and gamma. The instruments were calibrated at Hanford (June 22, 1949) before being taken to the Pacific Area and again (September 19, 1949) shortly after they were returned to Seattle. Corrections were slight. LIKIEP Likiep was monitored for the purpose of determining the approximate background count of an uncontaminated area of a similar environment to Bikini and Eniwetok, At Lado Island on August 20 the average of 7 readings on the beach sand near the water line was 20.7 c/m; on the beach sand near the vegetation line, the average of 10 readings was 21.1 c/m; and over dead vegetation, including pandanus, coconut and shrubs, the average of 10 readings was 26.6c c/m. _ BIKINI The activity of the atoll as a whole, as determined by monitoring, was low ° ; except for isolated spots of oil scum or wreckage from the target fleet that had drifted ashore. The count of living vegetation was about twice as great, and of dead vegetation, about three times as great as counts for beach sand. At Bikini counts over beach sand averaged about 30 per minute as compared to 2] per mainuté he =e for Likiep. However, readings from patches of oil scum and of target drift items “ Un Tyener: y TNIV. oe 4 Scrat ra Oo