Radioactive Contamination of the Indo-Antarctic Ocean Water in Each Earlier Period in 1961 and 1962

Abstract

Significant increase of Ce-144 concentration was detected in the Indo-Antarctic surface sea water collected in early 1962 (mean 0.57 μμ/l), comparing with those of early 1961 (mean 0.12 μμc/l), and was supposed to be caused by the stratospheric fallout injected by the resumption of nuclear explosions by USSR on the northern polar region during September to November, 1961. On the other hand, no increase of Sr-90 concentration was detected in these samples (means 0.07 and 0.06 μμ/l) and that of Cs-137 concentration was slight (means 0.13 and 0.15 μμ/l).
The horizontal distributions of the radioactive nuclides in surface water indicate the decreasing Sr-90 and Cs-137 concentrations with increasing latitude, but no latitudinal variation of Ce-144 is detected.
By comparison of Ce-144 concentrations in early 1961 and 1962 samples, only 6 months of minimum time is estimated for the transport of stratospheric fallout debris from the northern polar region to the southern hemisphere, and this value is considerably shorter than those reported by other workers.