Successive determinations of210PB,210PO,226RA,228RA and selected actinides in seawater and sea sediment

Plutonium 239,240 was measured using large-volume water samples from the North Pacific and its adjacent seas. The vertical profiles of^239,240Pu show features that are similar to those reported in earlier papers with a subsurface maxima of around 660 m and a significant concentration increase in the North Pacific bottom waters. It became evident that the^239,240Pu concentration in deep bottom water is proportional to the inventory of the nuclides in the overlying water column and that the appearent distribution ratios of the nuclides between deep-sea sediment and bottom water lie in a relatively narrow range of about 2×10⁴ to 10⁵, independent of sea area and warter depth. The latter implies that^239,240Pu may follow a reversible-type partition process at a deep water/sediment interface. In order to substantiate this assumption, it is desirable to study the phenomenon for Pu as well as for other long-lived radionuclides, both artificial and natural. From this point of view, an analytical procedure for the successive determination of selected long-lived radionuclides was studied.