Part of transpired the by island plants. rainfall Essentially fraction of the rain infiltrates groundwater table. evaporates no the soil is taken is lost by up and partially surface runoff. column and eventually reaches On many of the larger islands a the groundwater is fresh enough for human consumption, determined effort to ensure containment systems above ground, storage capacity drinking water. to the may and at some be a year-round supply of There has rain water in but when unanticipated droughts occur, exhausted and groundwater must be relied the on for Any radionuclides that have migrated through the soil column groundwater individuals the the upper atolls this water is used for household purposes and garden crops. been A The surface of the water table in the Marshall Islands is between 2.5 and 4 m below ground. layer of water or will contribute it. Therefore, consuming some an internal evaluation radiological of dose to the ‘significance of radionuclides detected in both the cistern water and groundwater was necessary to meet the survey objectives. There were 55- to 100-1 samples collected for analysis from cisterns and well pits. filtered were Unfiltered water was collected from the cisterns; groundwater was through returned processing. 239+240 Pu, salinity. 1l- and 0.45-p filters to One and the Lawrence separation 241 from Standardized samples. The procedures. 9,10 remainder, A with fraction prepared Livermore technique all used of solutions were of National was samples carrier radionuclides to remove particulates. standards, samples isolate water was duplicates, to purified analyzed and blanks samples (LLNL) 906, regardless added radiochemically the Laboratory to were All > water acidified using at 13765 of the for published LLNL were and sent the to a contractor laboratory. Radionuclide concentrations since 1975 are “hown in Table 2. in cistern water sampled at Bikini Atoll Table 3 lists concentrations in cisterns and other fresh water supplies at other Northern Marshall Islands Atolls. The Likiep, concentration of Ailuk, concentrations Mejit, radionuclides Wotho, in groundwater and Ujelang are at Rongelap, shown in Table 4. Groundwater at Bikini and Enewetak have been previously discussed more recent results from these atolls will appear in future reports. Utirik, 3,11 and