—p 342 RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL The many coaxial cable trenches across segments of Enjebi also promoted mixing and marbling. Their locations were made apparent by ridges of soil and denser vegetation than that of surrounding areas. Some cable trenches were as deep as 5 feet. Often, cables had been excavated and replaced for succeeding operations, resulting in further mixing when the cables were recovered. All these factors made Enjebi soil cleanup as complex a problem as Runit soil cleanup and, in terms of total cubic yards of soil to be removed, as vast an effort as Runit cleanup. The DOE-ERSP fine soil survey of Enjebi began in August 1977 to define areas for soil removal. Actual soil removal operations began soon after the 4 May 1978 soil cleanup conference, at which the Director, DNA decided to attempt the cleanup of Enjebi for possible future residential use. The conference decision left open the ultimate cleanup level, recognizing that resource limitations might dictate stopping at 50 pCi/g or someother value; however, 40 pCi/g was clearly the desired target. (The island met the criteria for agricultural use, 80 pCi/g, without removal of any soil.) In April 1978, DOE-ERSP estimated 44,835 cubic yards of soil would haveto be excised from 20.75 hectares to achieve residential levels of transuranics, This volume estimate subsequently was revised to 54,300 cubic yards. !!.12 Field surveys and staking of areas requiring soil removal began on Enjebi on 27 June 1978 (Figure 7-11). Actual soil removal began on 6 July 1978 in areas measuring over 60 pCi/g, from which 2,580 cubic yards of soil were removed. Another16,492 cubic yards of soil were removed from areas measuring over 50 pCi/g between 14 July and [4 August 1978. The procedure of removing the highestlevels first revealed that such hot spots had a ‘“‘halo”’ effect on soil survey data; i.e., they had given surrounding areas the appearance of containing greater levels than was actually the case. Resurveyof those areas after the hot spots were removed resulted in lower readings, fewer areas to be excised, and decreased volumes ofsoil to be removed. Thus, experience showed that subsurface contamination was muchless of a problem than had been anticipated in the application of the ‘‘Treat Factor.”” ENJEBI SUBSURFACE CONTAMINATION In September 1977, DOE-ERSP had outlined to Commander, JTG (CJTG), a plan for subsurface exploration of the Easy, X-Ray and Item GZsites on Enjebi. The plan was to verify NVQ-140 data by backhoesoil profile sampling. Field Command had nowestablished the priority for ERSP support to the fine survey of Boken (Irene), Lujor and the characterization of Runit. As a result, the subsurface exploration plan was not implemented until January 1978.