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BIOMEDICAL AND AEROSOL STUDIES ASSOCIATED WITH A FIELD RELEASE OF PLUTONIUM

Wilson, R H; Thomas, R G; Stannard, J N

REPORT

1960 Nov 01

Unknown

pages 67

NV0004330

WT-1511

Rochester, N.Y. Univ. Atomic Energy Project

1961 Dec 31

2022 Jun 23

Oh Apr. 24, 1957, a high-explosive detonation was employed at the Nevada Test Site to release plutonium for field study of this fissile material as a contaminant. Che of four major measurement programs was a biomedical experiment which comprised exposure of animals to first deposition of plutonium oxids from the dstonation cloud (acute subjects) and to the wind-induced resuspension of contaminnation (chronic subjects) as long as six months after original deposition. Acute subjects (26 dogs and 40 rats) were arrayed 500, 1000, and 2000 ft downwind froza ground zero, and nine rate were flown on balloon cables positioned to intercept the cloud 500 ft from ground zero. Chronic subjects (three grcups of 24 dogs and 3 burros) were placed, after a rough ground- activity survey, at climatologically probable downwind segments of isopleths marking nominal contaminations of 1000, 100, and 10 mu g of plutonium per square meter. Serial sacrifices of dogs were made at 4, 5, 16, 32, 64, 125, and 161 days after detonation. Ten tissues per aninual were assayed by radiochemistry and autoradiography for plutonium content. All burros received ths full 161-day exposure. Ten sheep were distributed among the three field positions on the 32nd day, at which time four additional dogs were placed at the middle position (100- line). All late animals stayed until the end of the maximum exposure period. Air samplers at each chronic field position documented daily mean air concentrations. The pattern of plutinium uptake was surprising in that statistically important numbers of acute and chronic animals showed significant bone burdens in an exposure situation for which lung alone was to have been the critical organ. This outcome was most unusual for acute animals sacrificed less than 4 hr postdetonation. In general, however, all uptakes were less than the forecast amounts. The factor of 100 difference between ground-level contumination at near and far chronic stutions brought uptake differences of less than a factor of 10 to indicate that air-borne material accumulates along the upwind path. Air concentrations bear small if any relation to the at foot contamination for natural resuspension forces (wind). An explanation is advanced for the fact that, in an experiment designed to find time dependence in plutonium uptake, no tissues measured exhibit a correlation witu exposure time, save GI tract and contents. The plutonium found in bone suggests some deviation from the pure oxide form (extremely insoluble in body fluids) and the presence of solubilizing influences either in sarly parbculate formation or in animal lung. As yet no believable mechanism has been proposed. All autoradiography gave negative results. (auth)