560 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



Concentrations and Physicochemical States in the Water Column 



At each of the sediment sampUng stations, piutonium and americium were measured in 

 water collected at 2 m from the bottom and at 1 to 2 m from the surface. During the 

 collections in November 1972, the wind and wave conditions were typical of the winter 

 season — ESE and ENE as given in Fig. 4 (Noshkin et al., 1974). During the collections in 

 July 1976, the wind direction and velocity were essentially the same as those in 

 November 1972. The physical circulation of the water in the lagoon may be traced by 

 using the piutonium concentrations and distributions measured at lagoon stations away 

 from the northwestern quadrant. 



Distribution of'^^^''^^^Pu Concentrations 



With the use of all total piutonium concentration values obtained in 1972 by F. G. 

 Lowman, Puerto Rico Nuclear Center, V. Noshkin, Lawrence Livermore Laboratory, and 

 W. R. Schell, University of Washington (unpublished data) and the few additional values 

 obtained in 1976 for the lagoon water and by averaging the values when duplicate 

 collections were available for the same station, isopleths of the piutonium concentrations 

 for the surface and deep water of the lagoon have been constructed and are shown in 

 Figs. 12 and 13, respectively. These isopleths show clearly the distribution patterns of 

 piutonium, caused by the lagoon circulation, from its main source in the sediments of the 

 northwestern quadrant of the lagoon. With the use of 2 3 9,24 0pjj concentrations as the 

 tracer, the transport and circulation of the water in the lagoon have been estimated. The 

 surface water appears to be diluted by incoming ocean water through the wide pass near 

 Eneu and by oceanic water over the northeastern reef. The outlet of lagoon water is 



Kilometers 



Fig. 12 Distribution of 2 3 9,24opy concentrations in surface water (2 m) at Bikini 

 Atoll. Concentrations in picocuries per cubic meter. 



