Radioactivity in the Marine Environment (1971) / Chapter Skim
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EVALUATION OF HUMAN RADIATION EXPOSURE
EVALUATION OF HUMAN RADIATION EXPOSURE
Pages 240-260
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From page 240... ...
. The International Atomic Energy Agency ad hoc panel on radioactive waste disposal into the sea has presented a reasonably detailed description of the step-by-step procedure that may be used in arriving at maximum permissible rates of introduction of radioactive materials into particular marine locales (IAEA, 1961)
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From page 241... ...
This critical volume approach was used by a working group of the National Research Council to evaluate the potential hazard of a sealed nuclear power source to marine fisheries. AVAILABILITY OF INTRODUCED MATERIAL TO MARINE BIOTA Most predictive calculations assume that radioisotopes added to seawater will be adsorbed or absorbed by marine organisms in a manner identical with that of their stable counterparts already present in solution in the seawater.
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From page 242... ...
. APPLICATIONS The critical pathway approach to evaluating the dose to critical population groups has been used for several radioactive waste disposal operations throughout the world: Nation Use United Radioactive waste disposal into Atlantic and Gulf States coastal waters Radioactive waste disposal from nuclear-powered ships Hanford (now Richland)
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From page 243... ...
In making a predictive calculation using the specific activity approach, many of the same parameters used in the critical pathway approach must still be applied. These are Detailed knowledge of the kinds and quantities of radioactive materials introduced Knowledge of or assumptions about the physical and chemical form of the radionuclides introduced Calculation of the initial dilution by mechanical mixing Calculation of the dilution that will result from natural mixing processes of the sea Assumptions about the relative availability of the introduced material to the marine biota Parameters used in the critical pathway approach that are not needed with the specific activity approach are Assumptions about the concentration of radionuclides by marine organisms from the seawater Knowledge of the kinds and quantities of marine products used as food.
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From page 244... ...
In situations where the dose to man is of any real significance in respect to limits, it will be possible to make the measurements directly without the use of indicator species. The Windscale Evaluation: An Example of Acceptable Dose in Relation to the Radioactive Contamination of Coastal Waters The preoperational evaluation at Windscale, on the Cumberland coast of Britain, was the first detailed evaluation of radioactive material in the marine environment using the critical pathway approach.
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From page 245... ...
population, and allots 1/10 of the U.K. recommended genetic exposure rate from radioactive waste disposal (U.K., Minister of Housing and Local Government, Minister for Welsh Affairs, and Secretary of State for Scotland, 1960)
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From page 246... ...
. The 137Cs/K ratio in marine fish is much lower than that in milk and meat, so that the percentage contribution to retained 137Cs (and hence to the internal radiation dose)
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The Hanford reactor effluent enters the Columbia River about 360 miles upstream from the Pacific Ocean, but some nuclides persist and can be detected in the sea beyond the mouth of the river. (For information on the kinds and quantities of radioactive waste discharged to the marine environment, see Chapter 2.)
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From page 248... ...
. The radiation dose received by the small critical population group is 0.17 percent of the acceptable dose rate for the total body and 0.08 percent of that for the intestinal tract (Preston, 1968)
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From page 249... ...
The critical pathway for human exposure at two of the sites is predicted to be external radiation from silt contaminated by activated corrosion products. At the three other sites, the critical pathway is irradiation of the human intestinal tract by neutron activation products concentrated in fish flesh (Preston, 1966)
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Tarapur A preoperational assessment of critical pathways and radionuclides has been carried out for the Indian power station at Tarapur (Kamath et al., 1966)
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SUMMARY The addition of artificial radioactive materials to the marine environment results in some added radiation exposure to people who use the sea and its products. The magnitude of the additional exposure that results depends upon many complex relationships, however, and involves the kinds and quantities of radioactive materials added and the manner and place of their introduction.
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From page 252... ...
When an introduction of radioactive material into the marine environment is being considered, it is now conventional to identify the probable critical pathway of exposure and the individuals or critical population likely to receive the greatest exposure. Preoperational guides are then calculated that establish the maximum allowable rates of introduction of specific radionuclides.
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From page 253... ...
1966. Evaluation of the exposure resulting from the disposal of radioactive waste into the Columbia River, p.
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1966. Site evaluations and the discharge of aqueous radioactive wastes from civil nuclear power stations in England and Wales, p.
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CARTER, Chesapeake Bay Institute, The Johns Hopkins University, Baltimore, Maryland EGBERT K DUURSMA, Laboratory of Marine Radioactivity, International Atomic Energy Agency, Monaco THEODORE R
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SEYMOUR, Laboratory of Radiation Ecology, College of Fisheries, University of Washington, Seattle, Washington ARTHUR TAMPLIN, Lawrence Radiation Laboratory, Livermore, California W1LLIAM L TEMPLETON, Aquatic Ecology Section, Battelle Northwest Laboratories, Richland, Washington KARL TUREKIAN, Department of Geology, Yale University, New Haven, Connecticut HERBERT L
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From page 257... ...
Bikini Atoll, 1 Vegetation-radiation studies, 234 Bikini Atoll nuclear experiments Drosophila gamma dose, 233 Drosophila genetics, 233 Insect populations, 233 Biodeposition rates, 193 Biological activity Columbia River, 154 Biological deposition Laboratory experiments, 193 Biological diffusion coefficient, 154 Biological factors variations, 163 Biological reconcentration processes, 241 Biological transport, 185 Rates, 183 Biological turnover rates, 165 Biota Trace elements transport, 161 Black Sea Cesium-137/strontium-90 ratio, 71 Blackwater Estuary Bradwell discharge limits (Table 3) , 256 Bomb debris-seawater interaction, 16 Bottom sediments Exchangeable nutrients, 192 Japanese oyster farm contamination, 192 Reducing environments, 192 Box model calculations, 119 Burrowing organisms, 154 Calcareous exoskeletal material, 143 Carbon-14 concentration calculations, 127 Vertical profiles (Table 8)
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From page 258... ...
, 3, 230 Dounreay radionuclides discharge Radiation exposure in fish nets, 253 Eastern Pacific Ocean surface water Strontium-90 mean annual concentration (Table 3) , 47 Ecology, 200 Tracer experiments, 217 Ecology-environment relationships, 200 Ecosystem radiation exposure, 206 Ecosystems, 200 Artificial radioactive exposure, 203 Instruments-community structure relationships, 201 Marine environment, 200 Physicochemical environment, 203 Simulation models, 3 Ecosystems radioactivity exposure, 204 Ecosystems-species interdependency, 213 Eddies, 91 Nonhomogeneous characteristics, 107 Nonstationary characteristics, 107 Eddy diffusion Cape Kennedy, offshore region, 115 Element concentration Biologically active, 138 Carbon depletion, 143 Deep water-surface water ratios (Table 5)
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From page 259... ...
225 Fresh water-seawater mixing Ionic radionuclides, 163 Gamma radiation in fish, 231 Gamma spectrometry Radionuclides in seawater, 77 Generating plants Nuclear powered, 6 Genetic exposure, 250 Dosage calculations, 250, 251 Windscale studies, 251 Glacial clays in seawater Radionuclide sorption, 157 Global ocean circulation, 92 Global radionuclide fallout Cesium-137 in deep ocean, 69 Strontium-90 in deep ocean, 69 Groundwater contamination, 21 Gulf of California Iodine-131 in coastal waters, 77 Gulf of Mexico Iodine-131 in coastal waters, 77 Gulf Stream currents, 100 Hanford radionuclides discharges Columbia River, 254 Oyster contamination, 254 Reactor effluents Biological effects, 228 Chemical toxicity, 228 Hexavalent chromium, 228 Radioactivity, 228 Thermal increment, 228 Hanford Reprocessing Plant, 254 Human ecology-marine environment relationships, 214 Human radiation exposure, 242, 253 Hydrosphere waste deposition, 218 Hydrosphere-biosphere relationships, 161 Hyperactivity in fish, 231 (See also Radiation dosage) ICRP (See International Commission on Radiological Protection)
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From page 260... ...
, 210 Radiosensitivity, 230 Regeneration rates, 170 Stable elements distribution, 161 Surface adsorption, 166 Trophic levels, 208 Marine organisms-environmental equilibrium characteristics, 165 Marine organisms feeding Mucous threads, 206 Marine organisms radiation exposure Species interactions, 205 Marine organisms-radioactivity absorption, 204 Marine organisms-radionuclides accumulation interaction, 161 Marine phytoplankton-radioactivity absorption, 204 Marine plant consumption, 241 Marine population control, 212 Marine products Consumption, 247 Contamination, 249 Laverbread contamination, 250 Marine resources studies, 235 Marine sediments, 147 Radionuclide sorption, 147 Vertical movement, 153 Marine species diversity, 212 Marine suspensoids Radioactive fallout association, 204 Radionuclide waste associations, 204 Marine-terrestrial food chains, 206 Mass balance deficiency, 17 Mathematical models Abstract phases, 201 Atmosphere, 201 Biosphere, 201 Fisheries resources, 201 Hydrosphere, 201 Hydrographic smooth curves, 202 Marine resources management, 201 Nickel in Atlantic Ocean, 202 Numerical predictions, 202 Predictive uses, 202 Psychological factors, 202 Theoretical studies, 202 Troposphere-stratosphere interchanges, 201 Use procedures, 202 Metals in seawater, 166 Microbial epiphyton-estuaries relationships, 191 Microdosimeters, 236 Natural aerosols, 11 Natural radioactivity, 7, 244, 251 Cosmic rays, 224 Natural radionuclides (Table 2) , 8 Seawater radioactivity, 2 Natural vs.
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