-17-
The per cent of activity remaining on the filters in
those samples filtered at date of collection (August 8 - 14,
1958) 1s 5 to 170 times that found in the samples filtered
January 13,
1959.
Thus a considerable amount of leaching
occurred during the intervening period.
of plankton from the Collett survey, other specimens collected
at Eniwetok, Bikini,
Rongelap, Ujelang, Utirik and Wotho
Atolls in the Marshall Islands,
Caroline Islands,
Kapingamarangi Atoll in the
Tarawa Atoll in the Gilbert Islands,
and
Kusaile and Ponape Atolls in the Senyavin Islands were examined
by gamma spectrometry for the photopeak (0.055 MEV) of w185,
The isotope was found only in samples from Eniwetok, Bikini,
Rongelap and Ujelang Atolls.
Eniwetok Atoll Samples
Chemical separations were made on Seaevola leaves from
Belle Island by ton-exchange and precipitation methods.
In the
anions from the ion-exchange column only the peaks of energy
represented by wi85 and Zr99-Nb?? were observed in the gamma
spectra.
Rul03+106_p,103+106 were driven off by heat in the
ashing process.
In the precipitation separation,
specific for tungsten,
which is
only the 0.055 MEV photopeak and the 0.03