port assumptions may be necessary.
cattle, however, may be in the barn during a
REFERENCES
tional amounts are depleted by grazing. The
portion of the year consuming feed obtained
during the previous harvest season. The level
of strontium 90 in milk, therefore, reflects the
concentration of strontium 90 in the pasture
feed and in the barn feed. Based on these assumptions, the model includes the following
factors: deposition rate, rate of absorption
from the soil, the residence time of strontium
90 on the plant, and the proportion of cows on
pasture feed and of cows on barn feed. The
derived equation allows values for specific areas
to be considered for a particular time period.
The modelis fitted to approximately 5 years
of observed milk measurements from five metropolitan areas comprising the original raw milk
sampling network. Deviations of the observed
values from those given by the model are interpreted as fluctuations arising from experimental error or secondary perturbations or
both. Calculated values were generally found
to be reasonable. A higher degree of reliabil-
more accurate predictions of strontium 90 concentrations in milk. Modifications of the trans-
(1) Knapp, H. A: The effect of deposition rate and
cumulative soil level on the concentration of
strontium 90 in U.S. milk and food supplies.
U.S. Atomic Energy Commission TID-—13945.
U.S. Department of Commerce, Washington 25,
D.C., October 1, 1961.
(2) Harris, B. K., Licking, D. S., and Crounse, J. B.:
Mathematical models of radionuclides in milk.
Pub. Health Rep. 76: 681-690, August 1961.
(3) Kulp, J. L., and Schulert, A. H.: Strontium-90
in man V. Science 186: 619-632, May 18, 1962.
(4) U.S. Atomic Energy Commission, Health and
Safety Laboratory: Fallout program quarterly
summary report. U.S. Department of Commerce, Washington 25, D.C., April 1, 1962.
(§) Minnesota Department of Health, Division of
Environmental Sanitation, and University of
Minnesota, Institute of Agriculture: A report
on strontium 90 in milk produced in the Brainerd milkshed. Contract No.
SAph
738798.
September 30, 1961. Mimeographed.
(6) St. Louis County Heaith Department: Factors
contributing to the occurrence of radionuclide
levels in market milk. Contract No. SAph
73763. Mimeographed.
Biological Serial Record Center
The Biological Serial Record Center, a de-
1064
20,000 serial publications began in October
pository for bibliographic information on the
world’s biological journals,is being established
in Washington, D.C., by the American Institute of Biological Sciences.
When its files are ready, the new center
will enable biological and other scientists to
find in oneplacetitles usually recorded either
in major libraries or inspecial libraries, collections, or prepared lists. It will provide
scientists with complete information on journals pertinent to their work. This informa-
1962. In addition to makinglibrary searches,
the center’s staff is requestingserial titles from
posited with appropriate libraries. The
center will not collect publications.
The work of the center, which is an activity
of publication, coverage by abstracting agen-
the Division of General Medical Sciences, Na-
publishers and scientific organizations and
asking biologists traveling to foreign countries
to obtain specific information on serial literature.
Publications acquired in the course of accumulating bibliographic data will be de-
tion will include addresses, editor’s name, nature of contents, price, language and frequency
of the Biological Sciences Communication
Project, is supported by a 3-year grant from
cies, and format.
Identifying and recording of approximately
tional Institutes of Health, Public Health
Service.
Public Health Reports
27
ity in predictions of deposition may result in
The strontium 90 is deposited on the pasture.
Some is retained on the foliage and someis
taken up by the soil. Precipitation causes some
of the strontium 90 to be washed off and addi-