PRELIMINARY REPORT ON THE SEDIMENTS AND RADIO ACTIVITY IN THE VICINITY OF THE COLUMBIA RIVER EFFLUENT. BROWN BEAR CRUISE 291, 29 JULY TO 12 AUGUST 1961 BROWN BEAR CRUISE 311 23 JULY TO 14 AUGUST 1962
WASHINGTON UNIV SEATTLE
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The sediments in the area affected by the runoff from the Columbia River were studied to determine the distribution of sediment types and the presence and amount of radioactivity in the sediments. The study of the dispersal processes and distributional patterns of the sediment and its radioactivity is in the initial phase of a three-phase program. Various sedimentological analyses of 178 samples provided preliminary data on sediment distribution. The inner part of the continental shelf is covered with sand which grades into silt along the outer part of the shelf. The sediment of the abyssal plains is principally a silty clay, although local coarsening of the sediment is produced by the accumulation of tests of microorganisms. The presence of quartz sand in samples from thsal plain appears to be restricted to those samples collected from deep-sea channels. Analyses of the gamma-ray spectra of sediments collected near the Columbia River mouth in 1961 indicate that radio nuclides, in addition to the naturally occurring potassium-40, are present in the sediments. The sandy sediments from Grays Harbor and the beaches adjacent to the Columbia River had very low activities although chromium-51, zinc-65, cobalt 57 and cobalt-60 were detected.
- Radiation Pollution and Control