SWRHL-14r
DAIRY FARM RADIOIODINE STUDY
FOLLOWING THE PIKE EVENT
Delbert S. Earth, Chief, and Joel G. Veater, Biologist
Bioenvironmental Research Program
Southwestern Radiological Health Laboratory
U. S. Public Health Service
Department of Health, Education, and Welfare
Las Vegas, Nevada
November 23, 1964
This study performed under a Memorandum of
Understanding (No. SF54373)
for
U. S. ATOMIC ENERGY COMMISSION
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LEGAL NOTICE
This report was prepared as an account of Government sponsored work.
Neither the United States, nor the Atomic Energy Commission, nor any
person acting on behalf of the Commission:
A. Makes any warranty or representation, expressed or implied, with
respect to the accuracy, completeness, or usefulness of the information
contained in this report, or that the use of any information, apparatus,
method, or process disclosed in this report may not infringe privately
owned rights; or
B. Assumes any liabilities with respect to the use of, or for damages
resulting from the use of any information, apparatus, method, or
process disclosed in this report.
As used in the above, "person acting on behalf of the Commission"
includes any employee or contractor of the Commission, or employee
of such contractor, to the extent that such employee or contractor of
the Commission, or employee of such contractor prepares, dissemin-
ates, or provides access to, any information pursuant to his employ-
ment or contract with the Commission, or his employment with such
contractor.
AUTHORS' COPY
059
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SWRHL-14r
DAIRY FARM RADIOIODINE STUDY
FOLLOWING THE PIKE EVENT
by
Delbert S. Earth, Chief, and Joel G. Veater, Biologist
Bioenvironmental Research Program
Southwestern Radiological Health Laboratory
U. S. Public Health Service
Department of Health, Education, and Welfare
Las Vegas, Nevada
November 23, 1964
This study performed under a Memorandum of
Understanding (No. SF 54 373)
for
U. S. ATOMIC ENERGY COMMISSION
-------
ABSTRACT
Following the Pike Event at the Nevada Test Site on March 13, 1964,
a small amount of radioactivity accidentally escaped from the ground.
The resulting radioactive cloud passed over two dairy farms in the
vicinity of Las Vegas, Nevada. Arrangements were made with the
managers of these farms to cooperate in a study of the uptake kinetics
of I in dairy cattle under normal dairy farming practices.
Each herd -was separated so that at each farm there were three cows
eating fresh green chop with the remainder of the herd on hay and
stored feed. Peak levels observed in the milk of cows on green chop
were 420 picocuries per liter (pc/1) at one farm and 70 pc/1 at the
other with an apparent decay half-life of approximately four days for
both. Peak levels in the milk of cows on hay were 70 pc/1 at one
farm and 40 pc/1 at the other. The apparent decay half-life at the
farm having the highest levels was approximately six days.
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ACKNOWLEDGMENTS
We wish to extend special thanks to the owners and operators of the
two farms. In particular, these include Mrs. Eunice Habbart. Mr
Floyd Miles and Mr. Nelson Gibson at the Habbart Farm, and Mr
Elaine Curtis, Supervisor, and Mr. Lynn Duke, Dairy Manager, at
the Latter Day Saints'Welfare Farm. Without the cooperative help
of these people and their associates, this study would not have been
possible. The support and encouragement of Mr Robert Thalgott,
Nevada Operations Office, Atomic Energy Commission, is gratefully
acknowledged. The liaison and cooperation of Mr Ferren Bunker,
Clark County Extension Agent, and Mr W W, White of the Nevada
State Health Department were also of considerable assistance in our
investigation. There were many friends and co-workers, too nu
merous to mention, at the Southwestern Radiological Health Labora-
tory who made valuable contributions and suggestions throughout the
study.
11
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TABLE OF CONTENTS
ABSTRACT i
ACKNOWLEDGEMENTS ii
TABLE OF CONTENTS iii
LIST OF TABLES iv
PART I. INTRODUCTION 1
PART II. SAMPLE COLLECTION 5
A. Milk Sampling 5
B. Feed Sampling 6
C. Water Sampling 7
D. Air Sampling 8
E. Soil Sampling 8
F. Beta plus Gamma Dose Rate Survey 8
PART in. ANALYTICAL METHODS 9
PART IV. DISCUSSION OF RESULTS 11
A. Habbart Farm 11
B. LDS Farm 16
PART V. CONCLUSIONS 20
REFERENCES 23
APPENDIX 24
111
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LIST OF TABLES
Table 1. Average production of experimental cows 3
Table 2. Annual summary of normal feeding practices for this
area. 4
Table 3. Summary of results. <^0
IV
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Part I
INTRODUCTION
Radioactivity was accidently released from the underground Pike
Event which took place at the Nevada Test Site at 0802 hours on
March 13, 1964. A portion of this material passed over the city
of Las Vegas, Nevada and parts of Clark County. In particular,
some fallout was deposited on and in the vicinity of two dairy farms
located near Las Vegas. These two farms were:
Latter Day Saints' Church Welfare Farm
6206 Munson Road, Las Vegas, Nevada and
Mrs. Habbart's Dairy Farm
6912 Pecos Road, Las Vegas, Nevada
The location of each farm is shown in Figure 1 in the Appendix.
Some descriptive information concerning the two farms will be found
in Figures 2 and 3 in the Appendix. The milk census forms consti-
tuting Figures 2 and 3 are representative of the records maintained
by the Southwestern Radiological Health Laboratory for milk pro-
ducers in Nevada and adjacent states.
This accidental occurrence provided a unique opportunity to study the
uptake of radioiodine into cow's milk under dairy farming management
conditions as practiced at these two farms. A plan was developed to
conduct a cooperative study bet-ween the Bioenvironmental Research
Program, Southwestern Radiological Health Laboratory, U. S.
Public Health Service, and the local dairy industry with the support
of the Nevada Operations Office, Atomic Energy Commission. The
design of the study -was discussed with Mr. Ferren Bunker, Clark
1
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County Extension Agent representing the University of Nevada Also
Mr. W. W White of the Nevada Health Department was informed of
the proposed study. General agreement on the objectives listed below
was obtained.
Four objectives -were established for the study. The first was to
measure uptake of radioiodine in fresh unpasteurized cow's milk as
a function of time at two separate dairy farms with two groups of
cows at each farm -- one group eating hay and grain only., and the
other group eating green chop, hay and grain. The second was to
measure the effect of green chopping* vegetation on its average
radioiodine content. As the third objective, levels of radioiodine in
the air would be measured continuously at the two dairy farms as a
function of time after a fallout event. The fourth objective was to
attempt to relate levels of radioiodine in the air; on vegetation or on
the ground to subsequent levels which appeared in fresh unpasteurized
cow's milk at the same location.
Arrangements were made to place three cows at each farm on green
chop, hay and grain while the remainder of each herd was maintained
on hay and grain only. It was not possible under the prevailing con-
ditions to make arrangements for a larger number •without imposing
an undue hardship on the cooperating farm managers It should be
noted that before arrangements could be finalized, all of the lac -
tating cows at Habbart's were fed one feeding of green chop on the
morning of March 17. This was the only time during the study that
*This is the terminology used for the standard practice of mowing
and machine chopping forage from irrigated fields Green chop is
fed to the dairy animals before it dries or spoils.
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either whole herd received fresh green chop. Prior to the study
no green chop had been fed to any of the cows in either herd.
All animals on green chop at both farms were Jerseys. The specific
animals involved in the study were selected by the farm managers
and in addition, all were in the late phase of their milk cycles and
thus -were somewhat below the herd average in milk production.
Table 1 indicates the average production of the experimental cows.
The average -was calculated during the study.
Table 1. Average production of experimental cows.
Identification
HABBART FARM:
Kay
Goldie
Gretta
LDS WELFARE
FARM:
60
40
30
Last Calving
Date
July 1963
July 1963
July 1963
June 1963
July 1963
Nov 1963
Milk/Day
(Ibs.)
22. 3
27. 0
22. 1
6.3
14. 6
19- 3
Butterfat
(%)
4.4
5.4
4.4
6.0
5.6
5.9
Dry fed cattle usually have a standard diet of hay, silage, and grain.
When silage is fed, the animals are normally fed hay and silage after
each milking and grain during milking. When the crops reach cutting
size and summer feeding practices begin, fresh green chop replaces
the silage. The Habbart operation fed hay and grain throughout this
study since the silage had already been consumed.
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Table 2. Annual summary of normal feeding practices
for this area
TYPE
OF
FEED
Hay
Silage
Chop
Grain
Estimated total daily feed fibs, /cow)
HABBART
Summer
15
20
10
Winter
15
20
10
LDS
Summer
15
20
6
Winter
12
10-15
--
13-15
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Part II
SAMPLE COLLECTION
All vegetation and soil samples -were collected in clean plastic bags,
sealed to eliminate cross contamination and loss of material, and
identified as to sample type, location, and time of collection (a. m. or
p.m. ). Milk and water samples were collected in clean disposable
one gallon containers.
A. MILK SAMPLING
Pipeline milking systems are utilized at both farms. Three
cows are milked at approximately the same time. The milk
flows from the cow along a central pipe and drains into a
bulk tank.
To minimize difficulty and interference with routine operations,
the three cows eating fresh green chop were milked simultane-
ously either at the beginning or at the end of each milking per-
iod. A one gallon composite sample was collected from both
the a.m. and p.m. milkings as the milk passed from the drain
pipe into the bulk tank.
Milk from the hay fed animals was collected in the same way,
except that the composite was a random sample and was not
necessarily from the same three animals during each milking.
It should be noted that the method of collecting samples from
the drain pipe was not effected until March 18. Previous samples
5
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•were drained from the bulk tank and sometimes included
composites of different milkings. All daily milk results re-
ported are the mean values of the results obtained from the
a. m. and the p. m. milkings for that day except when other-
wise noted.
B. FEED SAMPLING
Fresh green chop and dry feed •were sampled and analyzed for
radioiodine content. Also, fresh vegetation was hand cut from
the green-chopping field at Habbart's and analyzed by the same
methods to determine the effect, if any, of green chopping on
the radioiodine content. At Habbart's, chop was cut from a
stand of barley in a field measuring roughly two hundred yards
by one hundred yards. The average height was twenty inches
of which sixteen inches were cut for feed. Chopping was done
with a tractor driven forage chopper and blown directly into a
towed wagon. Fresh cuts were usually made every other day.
Soon after each feeding a sample was collected from the trailer
in which the chop was loaded. The field at the LDS Welfare
Farm was not fully grown so the chopping machine could not
operate. Instead, the feed was cut by hand with a
scythe. The area cut was a small section approximately
sixty feet square that had grown faster than the rest of the field.
This section consists mostly of barley with a mixture of al-
falfa. The stand averaged thirteen inches and the usual cutting
was nine inches. Sample collection was from the feeding trough
if available. If it was all eaten, the sample was cut in the field
from an area adjacent to the fresh cutting.
Most of the samples from the field consisted of one square meter
of vegetation cut to the same level as a chopped sample. For
6
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one study, specific spots were selected to determine if ac-
tivity was distributed uniformly or had an uneven pattern
(see Figure 4). Other samples were random collections, pri-
marily of barley. Alfalfa was collected by the square meter
to determine if it had the same retention as barley. The av-
erage daily green chop feeding was fifty-five pounds per
three cows at Habbart's and sixty-two pounds per three cows
at LDS.
Habbart hay was stacked completely exposed to climatic con-
ditions. The cows were fed this hay in a bin which extended
the length of the north side of the corral. Random samples
were taken from this bin and usually represented a cross sec-
tion of a bale. Also, some grain pellets -were collected and
analyzed.
Baled hay at the Latter Day Saints' Welfare Farm -was stored
in large stacks which were covered only with a protective roof.
Silage was stored in a trench silo partially covered with a
polyethylene film. Samples were collected from the troughs
by the same method used at Habbart's.
C. WATER SAMPLING
Both Habbart and LDS pipe well water to a trough about the
size of a bathtub (in fact, one was a tub). The water level is
float regulated and remains constant at all times. Samples
were collected by immersing gallon containers into the -water
in such a manner that mostly surface water was collected.
Rain collectors were placed at each farm during the experiment.
On April 1, 1964, there was a trace of rain. Also, there was
considerable wind and dust throughout the study.
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D. AIR SAMPLING
One General Metal Works high volume air sampler was placed
at each dairy farm. Mounted on the sampler were a glass fiber
prefilter and a Mine Safety Appliances Company charcoal car-
tridge. Filters and cartridges were changed daily.
E. SOIL SAMPLING
Daily samples were taken by collecting approximately one
square foot of topsoil from an undisturbed area at each farm to
a depth of approximately one-half inch.
F. BETA PLUS GAMMA DOSE RATE SURVEY
From March 13 to March 17, dose rate readings were taken
at each farm with an Eberline Model E-500B portable survey
instrument. Dose rate from beta plus gamma radiation was
measured both at ground level and three feet above ground in
the fields where vegetation samples were collected.
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Part III
ANALYTICAL METHODS
Liquid samples were placed in 3. 5 liter inverted well aluminum
beakers to be analyzed for gamma emitting radioisotopes using a
400-channel analyzer with a 4" x 4" Nal (Tl) crystal detector. Based
on fifty minute counts, the minimum detectable level for milk sam-
ples is 20 picocuries per liter (pc/1) with an associated error of
+_ 20 pc/1, or +_ 10%, whichever is larger. All values -were corrected
for decay to time of collection. Samples having less than the mini-
mum detectable level of activity at time of count were not corrected
to time of collection.
Depending upon size, vegetation samples were packaged in alu-
minum beakers or in 400 ml "cottage cheese" containers. Since
the sample size was non-standard, it was impossible to give a min-
131 2
imum level for I in pc/kg or pc/M . Instead, there was assigned
a minimum total activity of 100 pc per sample as the threshold of
detection. At 100 pc, the associated error due to counting statis-
tics is + 100%. Since the presence of fresh fission products com-
plicates the calculation (standards for some isotopes are not avail-
able), a value of +100 pc/kg, or +_ 50%, which ever is larger, was
assigned as the best estimate of the analytical error for all gamma
198
analyses of samples other than milk. The presence of Au made
131
the detection of I impossible in vegetation samples for about
ten days following detonation. The accuracy of I determinations
in soil samples was assumed to be comparable to that of vegetation
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measurements.
Air sample prefilters -were counted for gross beta activity with a
thin window, large area gas flow proportional probe connected to a
high speed sealer. The system has an efficiency of approximately
30% for 1. 5 Mev beta particles and background for this system is
575 _+ 20 counts per minute. Charcoal cartridges were examined
for gamma emitting radioisotopes by placing each cartridge directly
on a 4" x 4" sodium iodide crystal coupled to a 400-channel pulse
height analyzer set to view energies from 0 to 2 Mev. Assuming
no break in the prefilter, the activity on the cartridge should rep-
resent the gaseous fission products only. Detection efficiency for
this geometry is about 18% at 0. 51 Mev. The minimum detectable
activity is about 200 pc for any specific isotope.
The analytical limitations as described above are depicted graphi-
cally for each datum point in Figures 5 through 11.
10
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Part IV
DISCUSSION OF RESULTS
A. HABBART FARM
Green Chop
131
A plot of I levels in milk from cows eating green chop and
of I in the green chop is presented in Figure 5. From the
graph, the following observations may be noted:
a. The peak daily average milk value was
375 pc/1, which was obtained on March 21,
four days after the cows began to eat the
green chop. This average represents the
mean value of the a. m. and p. m. milkings
for that day which were 420 pc/1 and
330 pc/1.
b. The milk values decayed with an esti-
mated apparent half-life of 3. 8 days.
c. Extrapolation backwards indicates that
if the study had been initiated on March 13,
the probable maximum value observed
would have been approximately
700 pc/1 on March 17.
d. The peak measured green chop value
was 4700 pc/kg, which was obtained
on March 19.
11
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e. The green chop values decayed with an
estimated apparent half-life of 5. 3 days.
f. The ratio of the peak average value of
I in milk to the peak value in green
chop was 375 pc/1 to 4700 pc/kg, or
0.08 pc/1 to 1 pc/kg.
The decay half times are in general agreement with published
results1 > 2» 3» 4. The milk decay time is slightly lower than most
values from published studies, but is not significantly different
from the half-time of four days reported for one case3. The ratio
of pc/1 milk to pc/kg green chop is numerically quite close to the
analogous mean Windscale factor1 of 0. 09. Considering the differ-
ences in radioiodine sources, climatic conditions and farming prac-
tices for the two different cases, such agreement was not expected.
Furthermore, no profound significance should yet be attributed to
this finding since the agreement could be due to fortuitous combi-
nations of many unrelated factors. Clearly, additional experimen-
tation is needed. It should be pointed out that the value of 0. 08
calculated from our data actually has a possible range, based on
analytical accuracy of the two values used to calculate it, of 0. 05
to 0. 18.
Hay
A plot of I levels in milk of cows eating hay and of I in the hay
is given in Figure 6. From the graph, one may note the following:
a. The peak measured milk value was
70 pc/1, which was obtained on
March 16, three days after the Pike
Event. Both the a. m. and p. m.
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milkings for this day were 70 pc/1.
Note that the data for March 18 and
19 should be disregarded since, as
mentioned previously, all cows were
fed green chop on March 17-
b. The milk values decayed with an esti-
mated apparent half-life of 5. 9 days.
Again, the points on March 18 and 19
were disregarded.
c. The peak measured level in hay was
1300 pc/kg, which was obtained on
March 15.
d. The activity in the hay was so variable
that it was not possible to obtain a
good estimate of the decay half-time.
e. The ratio of the peak value of I in
milk to the peak value in hay •was
70 pc/1 to 1300 pc/kg, or 0. 054 pc/1
to 1 pc/kg. Based on the analytical
accuracy of the two quantities used to
calculate the number 0. 054, the pos-
sible range is 0. 026 to 0. 14. It is not
possible to compare these results with
published data since, to our knowledge,
no one else has observed significant
I values in the
only stored feed.
I values in the milk of cows eating
Distribution study
Figure 4 depicts several sampling locations in the field at the Habbart
13
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Farm from which the green chop was being cut. At each location
a one square meter sample was obtained as described previously.
The analytical results obtained are also given in Figure 4. Anal-
yses of these data shows that the mean value of the field sample of
I. was 704 + 253 pc/kg on March 27, where the +_ value is the
standard deviation. The fact that the standard deviation is less than
the estimated analytical accuracy is evidence that the contamination
of the field in pc/kg •was reasonably homogeneous over the field.
Furthermore, the measured I activity in. green chop on March 27
was 740 +_ 370 pc/kg. Comparing this to 704 +_ 253 pc/kg indicates
that no significant I activity was removed from the vegetation by
the green chopping process.
Calculations from these data also show that for this particular field
there were 1. 34 +_ 0. 88 kg green vegetation/square meter of sur-
face area.
The mean value of I on this field on March 27 may also be cal-
culated to be 743 jf 493 pc/M . The large standard deviation shows
that the activity in pc/M is considerably less uniform over the field
than is the activity in pc/kg. A possible contributory factor is the
fact that it was early in the growing season and the barley was not
constant in height over the field.
Soil
Figure 7 shows the levels of I found in undisturbed soil samples
at the Habbart Farm. The apparent decay half-life equals 8. 0 days,
which is precisely the physical half-life of I . Interpolation gives
an estimate of 2500 pc/kg for March 27. Each sample represents
approximately one square foot of surface area. In additon, the
14
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average soil sample weight was approximately 450 grams. Therefore,
2 2
for March 27, 2500 pc/kg corresponds to 1125 pc/ft or 12, 100 pc/M
2
of undisturbed soil. On March 27, the vegetation contained 743 pc/M .
131
Consequently, the percentage of I on the vegetation was 6. 1% of
that on the soil. In addition, extrapolation back to March 13 gives a
131 2
deposition estimate for I of 43, 000 pc/M of undisturbed soil.
Comparison of alfalfa to barley
Figure 8 presents I values for barley and alfalfa at the Habbart
Farm. The results clearly show that there is no significant dif-
ference between the two.
Miscellaneous samples
Air samples were taken from March 16 through April 10. All re-
sults for I were below the limit of detection of our analytical
instruments, indicating that there were no significant secondary
aerosols after the passage of the radioactive cloud.
From March 14, to March 17, beta plus gamma surveys at the
fields where the vegetation samples were collected registered 0. 02
to 0. 03 mr/hr, which is normal background for this area. Grain
supplement food pellets fed to cows at the Habbart Farm were
131
analyzed for I content -with negative results. This was to be ex-
pected since these pellets were protected by storage.
The analysis of water samples collected from the cows' watering
trough gave a peak reading for I of 100 pc/1 on March 15. The
levels were quite variable for the period March 15 to March 29f
averaging approximately 50 pc/1. It is not likely that the well pro-
viding water for the cows was contaminated since it is a deep arte-
sian well. Thus the most likely explanation for these findings seems
15
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to be that the cows •were contaminating the water with their saliva
and bits of uneaten food.
B. LDS FARM
Green Chop
A plot of I levels in milk of cows eating green chop and
of I in the green chop is presented in Figure 9. The
following observations may be made:
a. The peak daily average milk value was
65 pc/1, which was obtained on March 20,
three days after the cows began to eat
the green chop. This average represents
the mean value of the a. m. and p. m.
milkings for that day which were
70pc/l and 60 pc/1.
b. The milk values decayed with an estima-
ted apparent half-life of 4. 0 days.
c. Extrapolation backwards indicates that if
the study had been initiated on March 13,
the probable maximum value observed
in milk would have been approximately
110 pc/1 on March 17.
d. The peak measured green chop value -was
1700 pc/kg, which was obtained on March 21
e. The green chop values decayed with an
estimated apparent half-life of 5. 3 days.
f. The ratio of the peak average value of
131 *
I in milk to the peak value in green
chop was 65 pc/1 to 1700 pc/kg, or
16
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0. 038 pc/1 to 1 pc/kg. The possible
range on this number may be calcu-
lated to be 0. 018 to
The decay half times are in good agreement with the results ob-
tained at the Habbart Farm. However, the most likely ratio of
pc/1 of milk to pc/kg of green chop here is less than one -half the
one calculated for the Habbart Farm. A possible contributory
factor5 is the relatively much lower average milk production of the
L.DS cows on green chop vs. that of the Habbart cows on green chop
(see Table 1). The green chop I values here seemed to be lower
by about a factor of three than the values obtained at Habbart1 s Farm.
Hay
A plot of I levels in milk from cows eating hay is given in Figure 10.
Levels of I in the hay are shown in Figure 11. From these graphs
one may note the following:
a. The peak measured milk value was
30 pc/1, which was obtained on March 21,
eight days after the Pike Event. Both
the a.m. and p.m. milkings for this day
were 30
b. The peak measured level in hay was
630 pc/kg, which was obtained on
March 20.
c. The values are so erratic as to make any
calculation of decay half time for either
milk or hay unreliable.
d. The ratio of the peak average value of
I in milk to the peak value in hay was
30 pc/1 to 650 pc/kg, or 0.046 pc/1 to
17
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1 pc/kg. The possible range on this
number may be calculated to be 0. 010 to
0. 15.
The above results correspond reasonably well with the ones found at
the Habbart Farm, but in general the levels are lower by about a
factor of two.
T1^! ,
1 deposition per square meter
On several days one square meter samples of green chop were taken.
From the weights of these samples it was calculated that at the LDS
Farm there were 1.08 + 0.42 kg green vegetation per square meter of
surface area. This agrees with the corresponding value of 1. 34 jf 0. 88
for the Habbart Farm.
Soil
The values obtained were too variable to admit the determination of
a reasonable half-life of decay. The value obtained for March 26 was
500 pc/kg. The average soil sample weight was approximately 485 grams
Consequently, for March 26, 500 pc/kg corresponds to 242 pc/ft2 or
2610 pc/M2 of undisturbed soil. On March 26 the vegetation contained
131
600 pc/M2 . Thus the percentage of I on the vegetation was 23% of
that on the soil. This is considerably higher than the value of 6. 1%
calculated for March 27 at the Habbart Farm. A possible contributory
factor for this difference may be that at the LDS Farm the forage growth
was somewhat spotty and the areas where the forage was cut had higher
and more dense growth than the surrounding areas in the same field.
If one assumes that the soil levels at the LDS Farm decayed with a
half-life of 8. 0 days it is possible to extrapolate back to March 13,
* 13
the day of the Pike Event. This calculation leads to a value for I
8050 pc/M2 of undisturbed soil. This is lower by approximately a
18
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factor of five than the corresponding value obtained at the Habbart
Farm.
Miscellaneous samples
Air samples were taken from March 16 through April 10. All results
for I were below the limits of detection of our analytical instruments
On March 14 through 17, beta plus gamma surveys at the fields -where
the vegetation samples were collected registered 0.02 to 0.03 mr/hr,
which is normal background for this area.
The analysis of water samples obtained from the cows' watering
trough gave low, variable levels of I , averaging approximatel
25 pc/1 for the period March 15 through March 29.
19
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Part V
CONCLUSIONS
A brief summary of some of the results pertinent to the first objec
tive is given in Table 3.
Table 3. Summary of results.
TYPE OF
SAMPLE
Milk from
cows on
green chop
Milk from
cows on
hay
Green chop
(wet)
Hay
HABBART FARM
Max.
Value
I131
375*
pc/1
70*
4700
pc /kg
1300
pc/kg
Time to
reach max.
(days)
4
3
-
-
Decay
half -life
(days)
3. 8
5.9
5. 3
LDS FARM
Max.
Value
I131
65*
pc/1
30*
1700
pc/kg
630
Time to
reach max.
(days)
3
8
-
-
Decay
half -life
(days)
4, 0
5. 3
* Average of a. m. and p. m. milkings.
This summary plus the appended graphs show the measured uptake and
decay of I in the study cows under the conditions of this investi-
gation. Probably the most significant quantities in Table 3 are the
decay half-lives. Even though each specific reported value could be
in error by as much as plus or minus one day, it seems likely that
there may be a significant difference between the decay in the milk
from cows on green chop and the decay in the milk from cows on hay,
20
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The observed time of 8 days for the level of I to reach a max-
imum in the milk of cows on hay at the LDS Farm could -well be in
error by a considerable amount since the measured maximum value
of 30 pc/1 was quite close to our analytical detection limit.
Within the limits of accuracy of our analytical techniques it is con-
cluded that the process of green chopping forage does not remove an
appreciable amount of T
Since the air levels of I were below the limits of detectability of
our analytical methods, the third objective of the study was not
achieved.
131
Relationships between peak levels of I on cow's feed and peak
levels appearing in fresh unpasteurized milk at the same location
have been calculated and presented. As was shown there is consid-
erable variance to be expected in such relationships since they are
determined as the quotient of two quantities, each subject to its own
analytical error. Since the external beta plus gamma measurements
were background throughout the study it was not possible to calculate
relationships between these readings and subsequent milk levels of
i131.
It appears that, by a factor of 2 to 5, there was a significantly higher
deposition of I on the Habbart Farm than on the LDS Farm. Since
these farms were only five miles apart in a broad valley -with no sig-
nificant topographical features separating them, this finding casts
some doubt on the validity of the assignment of contamination values
to broad geographical areas based on a single reading at any one
location.
21
-------
Levels of I in milk of cows on dry feed only were significantly
higher than have been reported in other studies, This difference
undoubtedly was due to the common practice in this geographical
region of storing baled hay in the open.
Extreme caution should be exercised in attempting to use these
data in extrapolating past or possible future situations. It is
apparent that there is considerable variance found even in direct
measurements as exhibited in Figure 4. 240 pc/M2 of I was
found in a field approximately 200 yards from a location where a
value of 1700 pc/M2 was measured. Practices of attempting to
estimate I levels -which will be found in milk from external
gamma or beta plus gamma dose rate readings are particularly
subject to question. For example, utilizing such relationships in
this instance would have led to the conclusion that there -would have
131
been no measurable I milk levels found whereas our data mdi
cate that levels could actually have reached values near 700 pc/1
had the study been started at an optimum time.
Each different source of radioiodine can produce activity of different
characteristics which is then further modified by release conditions,
meteorological conditions, local climatic conditions and local dairy
farming practices. Thus, generalizations which purport to apply to
any and all situations are fraught with uncertainty
22
-------
REFERENCES
1- Booker, D. V., Physical Measurements of Activity in Samples
from Windscale, A.E.R.E. HP/R 2607, October, 1958.
2. Soldat, J. K. , The Relationship Between I1 3l Concentrations in
Various Environmental Samples, Health Physics, 9:1167-1171, 1963
3. Knapp, H. A. , Iodine-131 in Fresh Milk and Human Thyroids Fol-
lowing a Single Deposition of Nuclear Test Fallout, TID-19266,
June 1, 1963.
4. Bustad, L,. K, , D. H. Wood, E. E. Elefson, H. A. Ragan and
R. O. McClellan, 1-131 in Milk and Thyroid of Dairy Cattle Fol-
io-wing a Single Contamination Event and Prolonged Daily Adminis-
tration, Health Physics, 9:1231, 1963.
5. Squire, H. M. , L. J. Middleton, B. F. SansomandR. C. Coid,
The Metabolism in Dairy Cows of Fission Products, Progress in
Nuclear Energy, Series VI 3:69-90, 1961.
23
-------
APPENDIX
Figure Page
1. Locations of study farms. A-l
2. Milk census data collected at the Habbart Farm. A-2
3. Milk census data collected at the Latter Day Saints'
Welfare Farm. A-3
4. Area Sampling of Habbart's field for I activity on
March 27. A-4
5. I' in Habbart green chop and I in milk from cows
eating green chop. A-5
6.1 in Habbart dry hay and I in milk from cows
eating dry hay. A-6
7.1 in undisturbed soil at the Habbart Farm. A-7
8. Comparison of I in alfalfa vs. barley at the Habbart
Farm. A-8
9.1" in LDS Welfare green chop and I in milk from
cows eating green chop. A-9
10. I in milk collected from cows eating dry hay at the LDS
Welfare Farm. A-10
11. I in hay from the LDS Welfare Farm. A-ll
Note: The following symbols are used in the Appendix:
Upper Analytical Limit
Actual or Averaged Value Q
Lower Analytical Limit I
For plotting purposes, a value of not detectable is
plotted as half the value of the lower detection limit
e.g., the lower detection limit for I in milk is
20 pc/1, any value below this is considered not de-
tectable and is plotted in the following graphs at 10 pc/1.
24
-------
LDS WELFARE FARM
GREATER
LAS
VEG
HABBART FARM
Figure 1. Locations of study farms.
-------
Population: (Indicate
male or female; list
children individually)
Adults:
(2) 1 Male(s)
(4) 2 Female(s)
Children:
(6) 1
(7) 1
(8) 1
(9)
(10)
(11)
(12)
(13)
Age
(yrs)
Over 18
Over 18
10 yrs.
5 yrs.
3 yrs.
Raw milk
consumed daily
(in quarts)
(3) 1
(5) 1
Pasteurized Milk
ti 11
ii it
Home use
milk (qts
than drin
(17) To
(18) Ga
Home
Comr
None
Crop(s
(14) Total Adults : 3 (16) Total quarts raw milk
(15) Total Children: 3 consumed daily: 2
MILK CENSUS FORM
(1) Code: Fig. 2
Name : Eunice Habbart
Address: 6912 Pecos Road
Location: Las Vegas, Nevada
Date 3-17-64
County (or area) Clark
Barley
Oats
Cattle: Number of Milk Cows: 27
Breed(s): Jersey, Guernsey and
Holstein
Normal feeding practices:
(19) Dry feed
(20) Pasture
(21) Grain
(22) Concentrate
Inclusive dates
From
Nov.
Beef c
Dec.
Dec.
To
March
Dec.
Dec.
Type
Alfalfa hay
Source
Commercial & field
w.
r
Milk:
(23) Milk shipped to dairy 120 gals/day; Days of milk pickup Mon. Sat.
Name of dairy and location: Hinies Wed. Fri. Time: varies
626 Las Vegas Blvd So., Las Vegas,
(24)
Nevada.
T25) Grade of milk:
(A, B, or C)
Well
"Well"
Water Supply:
(26) Domestic use: Surface Municipal_
(27) Cattle source: Surface Municipal^
Other uses: (i.e., irrigation, etc.)
(28) Remarks: Quality of pasture? Home pasteurization?
pasture. No pasteurization at home.
_X_ Depth
X Depth
Artesian
Artesian
Irrigation
Good
Data collected by: Joel G. Veater
Figure 2. Milk census data collected at the Habbart Farm.
A-2
-------
MILK CENSUS FORM
(1) Code: Fig. 3
Name : LDS Welfare Farm
Address : 6206 Munson
Location: Las Vegas, Nevada
Date 3-17-64
County (or area) Clark
Population: (Indicate
male or female; list
children individually)
Adults:
(2) 4 Male(s)
(4) 4 Female(s)
Children:
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
2
1
1
2
2
2
Age
(yrs)
Over 18
Over 18
16 yrs.
15 "
14 "
10 "
6 "
4 "
Raw milk
consumed daily
(in quarts)
(3)
(5)
4
2
3
1
1
1/2
1/2
1/2
Home uses of raw
milk (qts. /day)other
than drinking:
(17) Total
(18) Garden:
Home
Commercial XX
None
Crop(s):
Hay
Grain
Silage
Pasture
(14) Total Adults : 8
(15) Total Children: 10
(16) Total quarts raw milk
consumed daily: 12-1/2
Cattle: Number of Milk Cows: 100 Breed(s): Jersey and Holstein
Normal feeding practices:
(19) Dry feed
(20) Pasture
(21) Grain
(22) Concentrate
Inclusive dates
From
Dec.
To
April
Beef only
Dec.
Dec.
Type
Hay & Silage
Source
Milk:
(23) Milk shipped to dairy 260 gals/day; Days of milk pickup Mon.Wed.
(24) Name of dairy and location: Arden Fri. Sat. Time: a. m.
1000 N. Main, Las Vegas, Nevada (25)
Water Supply:
(26) Domestic use: Surface
(27) Cattle source: Surface
Grade of milk:
(A, B, or C)
Municipal
Municipal
Other uses: (i. e. , irrigation, etc. )_
Quality of pasture?
pasture.
Well_X_ Depth 200 ft.
Well X Depth 200 ft.
(28) Remarks:
Home pasteurization? Good
No home pasteurization.
Data collected by: Joel G. Veater
Figure 3. Milk census data collected at the Latter Day Saints'
Welfare Farm. A-3
-------
(X)
240 pc/M
720 pc/kg
(X)
240 pc/M
480 pc/kg
(X
920 pc/M
£670 pc/kg
920 pc/M
650 pc/kg
(X)
(X)
800 pc/M
670 pc/kg
1700 pc/M
1300 pc/kg
295 pc/M
590 pc/kg
(X)
830 pc/M
550 pc/kg
X
Description:
Eight samples were taken from the field from which green forage was
chopped. Each (X) represents one square meter.
Figure 4. Area sampling of Habbart's field for I
March 27.
131
activity on
-------
1000
o
A
u
a
nl
GO
0
i—i
• H
^
O
a100
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\
^
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3/17
^
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29
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7
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n
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t
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4/2
Green
Milk f
green
.rent 1
x
i
chop
rom c
chop
lalf lii
|
y
k
ent
ha
\
\
^
\,
If life
,
(wet)
DWS e;
e=5.3
t
i
>
= 3.8
4
.ting
days
k
K
days
'10
t-l
-------
>ry he
00
0
u
Pu
• iH
4J
U
100
3/22
3/24
3/26
3/28
3/30
4/1
4/3
4/5
100
ilk fi
om c
iting
dry hay (e: icept
Q IP fp.e
Hing
on C\T\
7
(U
A • •
Activity in
Ap >aren
half
life =
5. q
la
ro
I0i-
3/15
3/17
3/19
3/
21
3/23
t
3/25
3>27
329
TIME: MONTH/DAY 1964
ibbart
eating dry hay. A-6
Figure 6.1 in Habbart dry hay, and I in milk from cows
-------
4/5
4/7
TIME: MONTH/DAY 1964
,131
Figure 7. I in undisturbed soil at the Habbart Farm.
-------
2
u
fi
•H
•M
• r-f
\/\rt_
}\J\J
(
I
\r\f\-
IUU
3/
L (?
\
(
i
28 3/
(
i
/
ik
(
>
i
30 4
/
5 \
Jk
\
r
i.
'1 4
^ i
) (
A B
© A
^
>
/3 4-
irley
.falfa
^ t
y \
C
«» ,
•i <
5 4-
C
)
u t.
>
<
J> i.
'7 4
>
(
A L
>
,2k
/9
TIME: MONTH/DAY 1964
Figure 8. Comparison of I in alfalfa versus barley at the
Habbart Farm.
A-8
-------
0
A
O
c
a
n!
00
O
i—i
•i-t
,M
U
lOOft
£
IOO
10 -c
1
*-,
^-x
^~
•^
^•v
(
t
^ „_
^w
\
(
* ^
""^••^^
-^
•^
• «
1
i
\
t"--^
s ^(
^
^
^
Apt
(
^^^,
r
^
^
^^
arent
"^
A Gr
0 Mi
^
"--^
half
^
/
sen c
k fro
»
^
&
life =
<
^
lop (\
m co1
-y
Y
^ ^
i
4.0 <
1
-\
/et)
ws ea
^ App£
^
»
ays
<
in§ g
rent
*
r~"---^
>
^^
reen
naif 1
^^<
i
hop
fe =
^
,3 di
^-^
tys
1
u
a
3/17
3/19
3/21 3/23 3/25 3/27
TIME: MONTH/DAY 1964
3 29
3/31
Figure 9.1 in LDS Welfare Farm green chop, and I in milk
from cows eating green chop.
A-9
-------
(
0)
•i-J
•r-{
1 — 1
O
a
fi |Vj-
•rH
•rH
u
— 1
1 -
(
p
) (
-v
T r
\ r
\
\
*•
i
V /
v
\
) r
' i
> r
\
^ r
j r
3/17
3/19
3/21 3/23 3/25 3/27
TIME: MONTH/DAY 1964
3/29
3/31
,131
Figure 10. I in milk collected from cows eating dry hay at the
LDS Welfare Farm.
A-10
-------
1000-
100-
nt
t-,
oo
o
u
a
10-
i
3/19
3/21
3/23 3/25 3/27
TIME: MONTH/DAY 1964
3/29
131
Figure 11. I in hay from the LDS Welfare Farm.
A-ll
-------
DISTRIBUTION LIST
1-15 SWRHL, Las Vegas, Nevada
16 James E. Reeves, Manager, NVOO, AEC, Las Vegas, Nev.
17 Robert H. Thalgott, NVOO, AEC, Las Vegas, Nevada
18 Col. E. G. Halligan, DASA, NVOO, AEC, Las Vegas, Nev.
19 Otto H. Roehlk, OSD, NVOO, AEC, Las Vegas, Nevada
20 Gordon M. Dunning, DOS, USAEC, Washington, D. C.
21 JohnS. Kelly, DPNE, USAEC, Washington, D. C.
22 Phillip W. Allen, USWB, NVOO, AEC, Las Vegas, Nev.
23 Frank D. Cluff, USWB, NVOO, AEC, Las Vegas, Nev.
. 24 G. D. Ferber, USWB, MRPB (R-3.3), Washington, D. C.
25 Ernest C. Anderson, TOB, DRH, PHS, Washington, D. C.
26 James G. Terrill, Jr. , DRH, PHS, Washington, D. C.
27 Bernd Kahn, DRH, RATSEC, Cincinnati, Ohio
28 Arve H. Dahl, DRH, PHS, Rockville, Maryland
29 Raymond Moore, DRH, PHS, Region VII, Dallas, Texas
30 Northeastern Radiological Health Lab. , Winchester, Mass.
31 Southeastern Radiological Health Lab. , Montgomery, Ala.
32 Bryce L. Rich, LRL, Mercury, Nevada
33 Robert H. Goeckermann, LRL, Livermore, California
34 John W. Gofman, LRL, Livermore, California
35 Charles I. Browne, LASL, Los Alamos, New Mexico
36 William E. Ogle, LASL, Mercury, Nevada
37 Alvin C. Graves, LASL, Los Alamos, New Mexico
38 Harry S. Jordan, LASL, Los Alamos, New Mexico
39 Victor M. Milligan, REECo, Mercury, Nevada
40 Clinton S. Maupin, REECo, Mercury, Nevada
41 Brig. Gen. Delmar L. Crowson, Director, DMA, USAEC,
Washington, D. C.
42 Mail & Records, NVOO, AEC, Las Vegas, Nevada
43- 150 Author's copies
-------
OPTIONAL K»M NO. 10
1010-104
UNITED STATES GOVERNMENT U.S. PUBLIC HEALTH SERVICE-BSS
Memorandum
TO : Initial Recipients of Report, SWRHL-14r DATE: July 29, 1965
FROM
_Chief, Bioenvironmental Research Program
• Southwestern Radiological Health Laboratory
SUBJECT: Erratum to SWRHL-14r, "Dairy Farm Radioiodine Study Following the Pike
Event" (Dated November 23, 1964)
Correct the second figure on line three of page 17 to read 0.10 instead of
0.010. This was a typographical error.
D.S. Barth
------- |