Radiation Dose Reconstruction for Epidemiologic Uses (1995) / Chapter Skim
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Appendix A: Representative Dose Reconstruction Studies
Appendix A: Representative Dose Reconstruction Studies
Pages 103-111
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From page 103... ...
NEVADA TEST SITE The first modern dose reconstruction study done in the United States involved the Nevada Test Site (Voilleque and Gesell 1990~. At this location, roughly 100 above-ground tests of nuclear weapons were conducted in the 1950s; tests also occurred in the early 1960s.
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From page 104... ...
An early debate ensued on the possible options of performing such a study with one option being a "model only" study using existing fallout and atmospheric transport models. The option eventually selected was to make maximum possible use of the existing historic data, which consisted of more than 100,000 measurements of the external gammaexposure rate (Grossman and Thompson 1990)
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From page 105... ...
A preliminary thyroid dose distribution among children in the most heavily contaminated districts of Belarus who were under the age of 7 years at the time of the accident is provided in Table A-1. The estimated arithmetic mean thyroid doses in subgroups of the same populations vary from 0.21 to 1.06 Gy or 21-106 red (Table Am.
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From page 106... ...
Number % Number % Number % 0.00-0.03 15,128 46.66 9,637 67.68 24,675 53.08 0.03-0.75 8,951 27.61 2,975 20.88 11,926 23.55 0.75-2.00 4,924 15.18 1,345 9.45 6,269 13.44 2.00-5.00 2,428 7.49 251 1.76 2,679 5.74 5.00-10.0 693 2.14 28 0.20 721 1.55 10.0-20.0 274 0.85 4 0.03 278 0.60 20.0-30.0 20 0.06 20 0.04 30.0-40.0 2 0.01 2 :<0.01 TABLE A-2 Estimated Arithmetic Mean Thyroid Doses to Children Under Age 7 in the Most Contaminated Districts of Belarus (Gavrilin and others 1992) Oblast Number of Population Population Mean Thyroid (Province)
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From page 107... ...
FERNALD The Feed Materials Production Center (FMPC) located at Fernald, Ohio, was, between 1951 and 1989, a government-owned, contractor-operated facility for producing uranium metal products used as feed materials in the production of nuclear weapons.
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From page 108... ...
The options available to the dose reconstruction team were to use recent Fernald data for the earlier period, with a large degree of uncertainty applied to air concentration estimates, or to use a surrogate historic data set based on regional airport data. After examination of the meteorologic data available, it was concluded that the air dispersion predictions for the dose reconstruction study should be based on hourly wind and stability data from the Fernald meteorologic tower, with uncertainties based partly on the relationships between past and recent Cincinnati airport data.
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From page 109... ...
The population along the Techa River was exposed to both external and internal irradiation. External irradiation was caused by gamma radiation from 137CS, i06Ru, and 95Zr-95Nb in the flood plains, in vegetable gardens near houses, and inside houses.
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From page 110... ...
Dose reconstruction for other persons was begun in 1987 (more than 100,000 were considered to be potentially affected) and used whole-body counting where possible, dose rate measurements in front of highly contaminated persons for which whole-body counter measurements were not possible because of too high a count rate, and dicentric chromosome biologic dosimetry (Ramalho and others 1988~.
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From page 111... ...
Detailed measurements could not be carried out until several weeks after the accident, when inhalation and ingestion played a negligible part in the total exposure and uptake. In summary, the reconstruction of the doses of highly affected people was carried out by clinical evaluation, dose reconstruction by biologic dosimetry was severely hampered by the lack of calibration curves for combined external and internal 137Cs irradiation at a low dose rate, and case-specific exposure pathway analysis models (necessarily unvalidated)
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