SUMMARY STATEMENT OF FINDINGS RELATED TO THE DISTRIBUTION, CHARACTERISTICS, AND BIOLOGICAL AVAILABILITY OF FALLOUT DEBRIS ORIGINATING FROM TESTING PROGRAMS AT THE NEVADA TEST SITE

Technical Report · Wed Sep 14 04:00:00 EDT 1960

DOI:https://doi.org/10.2172/4124261· OSTI ID:4124261

Larson, K H; Neel, J W

Summary statements are given of significant findings related to the distribution characteristics, and biological availability of fall-out debris originating from testing programs at the Nevada Test Site during the past decade. The delineation of fall-out patterns has been accomplished by the use of aenial and ground monitoring surveys. Only about 25% of the total amount of fission products produced by tower-supported detonations were deposited within distances corresponding to fall-out time of H + 12 hr; a much smaller quantity was deposited by halloon-supported detonations. Fall-out particles less than 44 (For in diameter are presumed to be of the greatest biological significance. About 30% of the fall-out radioactivity from tower-supported detonations was contained in the 0 to 44 (For particles as compared to almost 70% for balloon-supported detonations. Fall-out debris from halloon- supported detonations was also much more water and acid soluble than was the debris from towel-supported detonations. The <44 (For fallout particles contained a higher percentage of Sr/sup 89/, Sr/sup 90/, Ru/sup 10/ / sup 3/, and Ru/sup 106/ than did larger sized particles. There was a higher percentage of these radioelements in the particles from balloon-supported detonations. Within distances corresponding to H + 12 hr fall-out time, balloon- supported detonations deposited a maximum of 0.13% of the theoretical total Sr/ sup 89/ produced; tower-supported detonations deposited a maximum of 2%. Tower- supported detonations also deposited a maximum of 7.2% of the theoretical total amount of Sr/sup 90/ produced. Beta decay curves approximated the T/sup -1.//sup 2/ decay expression from H + 12 to H + 6000 hr; gamma decay curves deviated to the extent that irradiation doses calculated by the observed decay values were 1.5 to 2 times > those calculated by the T/sup -1.//sup 2/ relationship. Fall- out radioactivity is apparently confined to the first 2 in. of the soil surface unless the surface has been mechanically disturbed. Most of the fall-out debris that was redistributed by various environmental factors after original deposition consisted of particles < 44 (For in diameter; the particles in this size range also represented the predominant contamination on plant foliage. Sr/ sup 90/ levels in surface soil ranged from 31.9 to 142 mc/sq. mile in virgin areas near known fall-out pattern midlines and from 7.5 to 22.7 mc/sq. mile in agricultural areas that in some cases did not coincide with fall-out pattern midlines. The accumulation of radioiodine by native animals was observed to be a function of distance from GZ. Ba/sup 140/, Y/sup 91/, Sr/sup 89/, and Sr/sup 90/ were major bone contaminants. Post-series sampling of native aminals indicated that the accumulation of Sr/sup 89/ was also a function of distance from the point of detonation; however, the Sr/sup 90/ accumulation by animals correlated poorly with the strontium unit levels in soils. The strontium unit levels increased in milk immediately following contamition of the farm with fall-out debris and then decreased with time as well as the amount of strontium associated with the cattle's diet. Observations during the past decade indicate that less than 10% of the total strontium produced from nuclear detonations at NTS has been deposited with 200 miles from the point of detonation. (auth)

• Research Organization: California. Univ., Los Angeles. School of Medicine
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-000427
• OSTI ID: 4124261
• Report Number(s): UCLA-438
• Country of Publication: United States
• Language: English

Related Subjects

AGRICULTURE
AIR
ANIMALS
ATOMIC EXPLOSIONS
BARIUM 140
BETA DECAY
BIOLOGY
CATTLE
CONTAMINATION
FALLOUT
FISSION PRODUCTS
GAMMA RADIATION
HEALTH AND SAFETY
IODINE
LIFETIME
MILK
MONITORING
NUCLEAR EXPLOSIONS
PLANTS
RADIOACTIVITY
RADIOISOTOPES
RUTHENIUM 103
RUTHENIUM 106
SOILS
STRONTIUM 89
STRONTIUM 90
TESTING
YTTRIUM 91