we ee ee eee : - wee tet ee mse en ey ageRRR TERY Te Oe HEIR ER Ap ct UNCLASSIFIED oeoecyan renrOreee rteee.bateany ABSTRACT The Marine Survey Unit had as its major objectives (1) the measurementof the residual radiation found in the living organisms of Eniwetok Atoll as a result of previous weapons tests in this area and (2) a resurvey of the area, following Mike shot, to determine the changein amounts, kinds, and distribution of radioactive materials. The field data were collected by seven specialists who collected plankton, algae, rats, birds, fish, plants, and invertebrate organisms from Oct. 20 to Nov. 11, 1952. The material collected was frozen for storage and shipment back to the Applied Fisheries Laboratory, whereit was identified, dissected, weighed, ashed, and measured for radiation in disintegrations per minute per gram of wet sample. The pretest survey showed measurable amounts of residual radiation on and in the living organisms collected from the stations along the eastern and northern portion of the Atoll. Fol- . lowing Mike shot the radiation level increased manyfold, especially along the northern and western portions of the Atoll. The amount of radiation found on and in the specimens was sufficient to destroy or damage these forms over a very wide area. Subsequent studies should determine the biological half life of the materials contaminating the ares, their shift in position with the currents, and the results of the contamination from radioactive materials upon the living forms of the Atoll. i