THE NORTHERN MARSHALL ISLANDS RADIOLOGICAL SURVEY: SAMPLING AND ANALYSIS SUMMARY ABSTRACT A radiological survey was conducted in the Northern Marshall Islands to document remaining external gamma exposures from nuclear tests conducted at Enewetak and Bikini Atolls. An additional program was later included to obtain - terrestrial and marine samples for radiological dose assessment for current or potential atoll inhabitants. This report terrestrial is the and marine first of a surveys. series Here we summarizing the results discuss the sample from the collection and processing procedures and the general survey methodology as well as present a summary of the collected samples and radionuclide analyses. In other reports we will address the radionuclide concentrations in cistern water, groundwater, " marine species, pathways; soil, plants, and animals and the estimated doses via the analytical methods and quality control program; and the estimated dose from all the exposure pathways these the data bank; for each atoll (i.e., external gamma, marine, drinking water, terrestrial, and inhalation). Over 5400 samples were collected from the 12 atolls and 2 islands and prepared for analysis including 3093 soil, 961 vegetation, 153 animal, 965 fish composite samples (average of 30 fish per sample), 101 clam, 50 lagoon water, 15 cistern water, 17 groundwater, and 85 lagoon sediment samples. A complete breakdown by sample type, atoll, and island is given here. The total number of analyses by radionuclide are 8840 for 241an, 6569 for }3%cs, 4535 for 739*24%py, 4431 for sr, 1146 for 7>8pu, 269 for 7*!pu, and 114 each for 239 Pu and 240 Pu. A complete breakdown by sample category, atoll or island, and radionuclide is also included. INTRODUCTION A radiological survey was conducted from September through Noventber of 1978 at 12 atolls and 2 islands in the Northern Marshall Islands selected by the Department of Energy (DOE). The primary purpose was to document remaining external gamma exposures for those atolls that may have received fallout from nuclear tests conducted at Enewetak and Bikini Atolls. In the latter stages