780
MARTIN
on July 14, 1962, indicated an initial '*'I concentration (on July 15) of
approximately 800 + 200 pc (n = 6). If we assume anf, value of about
3.0 x 10~° for pasture plants compared to approximately 7.5 x 107? for
desert shrubs, the initial concentrations of '*4J on pasture plants in the
vicinity of Currant, Nev., and Fruitland, Utah, could have been 400 and
320 pce/g, respectively.
If our hypothetical pastures, dairy herds, and human populations
had been located in these areas, the total '*4I intakes by people drinking
1 liter of milk per day could have ranged from 670,000 to 825,000 pc,
and the doses to the thyroids of children could have been 11.4 to 14.6
rem. With the use of the more optimistic parameters adopted by the
FRC, the estimated doses based on these intakes would be 9.2 and 11.3
rem. (N.B. These estimates are comparable to the highest estimates
reported by Pendelton et al.*” for stations located in other parts of
Utah).
Actually, there are very few milk cattle in the area of the Sedan
fallout field, and, since we collected no milk samples, our treatment
of the problem is strictly hypothetical. However, one sample collected
near Ely, Nev., and analyzed by the U. S. Public Health Service®? con-
tained 2800 pc '*'I/liter on July 24, 18 days after the detonation. If this
value represents the concentration at the time of milking, it could
indicate a possible thyroid dose of 2.6 rems.
Solutions to Eq. 13 indicate that ‘I intakes during periodsof7,
14, or 21 days following environmental contamination by a single fall-
out event should account for 42, 85, or 97%, respectively, of the total
potential intakes from t = 0 tot =~. Therefore the simplest counter-
measures
to avoid 85% or more of the potential biological hazard
related to '°!I would be (1) to feed cattle on stored feed for a period of
two or more weeks after a detonation or (2) to use the milk produced
during that period for making cheese or other dairy products that
would not be consumedfor a period of three or more weeks after milk
production.
REFERENCES
1. R. L. Lindberg, E. M. Romney, J. H. Olafson, and K. H. Larson, Factors
Influencing the Biological Fate and Persistence of Fallout, Operation Teapot,
Report WT-1177, University of California at Los Angeles, January 1959.
2. K, H. Larson, H. A. Hawthorne, and J. H. Olafson, Nevada Test Site Fallout:
Some Characteristics, Its Apparent Environmental Equilibrium and Biolog-
ical Availability, in Radioactive Fallout from Nuclear Weapons Tests, A. W.
Klement, Jr. (Ed.), USAEC Report TID-7632, pp. 4-24, February 1962.
3. R.S. Russell, Deposition of Sr®® and Its Content in Vegetation and in Human
Diet in the United Kingdom, Nature, 182: 834-839 (1958).
4. National Academy of Sciences, the Behavior of Radioactive Fallout in Soils
and Plants, Natl. Acad. Sci.—Natl. Res. Council Publ. No. 1092, 37 pp.,
1963.