RHENIUM - ITS CONCENTRATION IN PACIFIC OCEAN SURFACE WATERS

The average Be concentration in four widely-spaced Pacific Ocean surface seawater samples was found to be 0.0084 μg/l ± 17%. The amount of Re found in (or on) a brown kelp plant (Macrocystisintegrifolia) was 0.022 μg/g freeze-dried plant. The Re in seawater was found to exist as an extractable species. The concentration of Re in seawater had not previously been investigated (HØgdahl, 1963) and was expected to be only a trace. A procedure was developed to extract Re from seawater and to concentrate it for measurement by neutron activation analysis. The amount of Re in a sample was determined by the comparator method based on the reaction 185Re(n, γ)186Re. Details of the determination of very small amounts of Re in various materials by activation analysis are given in, e.g. Morris and Fifield (1961), Morgan (1965), Palino (1965), Ishida et al. (1966). Samples of Pacific Ocean surface water from an off-shore station near San Francisco (Farallon Islands) and from three weather stations in the Pacific were analyzed for Re. Rhenium was determined also in several samples of sea salts from evaporated seawater to provide a reference point for estimation of the fraction of Re present in seawater as an extractable species. A brown kelp plant, Macrocystisintegrifolia, which is known to concentrate iodine (kelly and Baily, 1951), was analyzed for Re. Rhenium has been shown to behave similarly to iodine in its deposition in certain biological systems, e.g. the thyroid (baumann et al., 1949). © 1969.