RADIOACTIVITY IN OCEANIC ORGANISMS

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1963

OSTI ID:4688429

Osterberg, C L

Zinc-65 aad chromium-51 (principally from the nuclear reactors at Hanford, Washington) and zirconium-95-niobium-95, rutheniuni-103, and cerium-141 (principally from Russian fallout) were measured in marine organisms and particulate material taken off the Oregon coast. Gamma-ray spectrometry, carried out at Hanford Atomic Laboratories, was used in the analysis of almost one hundred samples of organisms obtained from midwater trawl tows made at transects off Astoria, Newport, and Coos Bay, Oregon, between June 1961 and April 1962. Euphausia pacifica was found to make up the largest portion of the biomass, showing up in sufficient quantity for radioanalysis throughout the year. Zinc- 65, formed by neutron activation in nuclear reactors cooled by Columbia River water, provides a tracer of the river water at sea. Euphausiids near the mouth of the river contained up to 150 picocuries of zinc-65 per gram of dry weight, while even those taken 165 miles off Coos Bay (about 250 miles from the mouth of the river) contained about 10 picocuries/g depending on season. Euphausiids taken off southern California and from Alaska had about an order of magnitude less zinc-65 (than Coos Bay), indicating the Columbia River to be a major source of this isotope, although a lesser amount of zinc-65 does appear to be due to fallout. The Russian nuclear weapons tests of 1961 introduced a relatively heavy amouet of fission products into the northeast Pacific Ocean. These were quickly taken up by the plankton so that the spectra of etiphausiids, salps, and sergestids at times showed strong peaks due to zirconium-95 and niobium-95, ruthenium-103106, and cerium-141. The maximum activity measured was 618 picocuries of Zr/sup 95/--Nb/sup 95/ per gram of dry weight of euphausiids taken 45 miles off Astoria in November 1961. Many figures show the seasonal distribution of these fission products in euphausiids, indicating a hotspot'' of fallout off Astoria in November 1961 which gradually dissipated by the following spring. The figures show no apparent correlation between fallout radioactivity and zinc65, probably indicating independent sources of the two. Radioactivity at three trophic levels was examined using membrane filters to sample phytoplankton (first trophic level) and detritus. Euphausiids represent a second trophic level, while lantern fish (whose stomachs contained principally euphausiids) represent a third trophic level. Zinc65 was found in the higher trophic levels, but appeared on filters only near the mouth of the Columbia River. The fission products (Zr/sup 95/-- Nb/dup 95/, Ru/sup 103-106/ and Ce/sup 141/) appe ared both on the filters and in euphausiids, but were greaily discriminated against at the third trophic level. Chromium51, formed at Hanford by neutron activation, was the most prominent gamma emitter on filter samples taken near the mouth of the river, but was nearly absent at higher trophic levels. Euphausiids are considered to be important agents in the vertical trsnsfer of radionuclides in the ocean because they: (1) concentrate radiosctivity, (2) make up the largest biomass in the macroplankton, (3) are forage for many predators; and (4) make extensive vertical migrations across the thermocline, feeding at the surface at night, and moving into the depths in the daytime. (Dissertation Abstr., XXIII, No. 12(I))

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-17-030255
• OSTI ID: 4688429
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACTIVATION
ACTIVATION ANALYSIS
ALASKA
ALGAE
ANIMALS
BIOLOGY AND MEDICINE
CALIFORNIA
CERIUM 141
CHROMIUM 51
COLUMBIA RIVER
COOLANTS
CRUSTACEANS
DIFFUSION
DISTRIBUTION
EUPHAUSIA
FALLOUT
FILTERS
FISH
FISSION PRODUCTS
FOOD
GAMMA RADIATION
GAMMA SOURCES
HAPO
LEVELS
MEASURED VALUES
MEMBRANES
METABOLISM
NEUTRONS
NIOBIUM 95
NUCLEAR EXPLOSIONS
OREGON
PACIFIC OCEAN
PLANKTON
PLANTS
QUANTITY RATIO
RADIOACTIVITY
REACTORS
RESIDUES
RUTHENIUM 103
RUTHENIUM 106
SALTS
SAMPLING
SEA
SPECTRA
SPECTROMETERS
STOMACH
TESTING
USA
USSR
VARIATIONS
WASHINGTON
WATER
WEIGHT
ZINC 65
ZIRCONIUM 95