SWRHL-85r
Radionuclide Studies with Dairy Cows
Following Two Plowshare Experiments.
by
Stuart C. Black, Erich W. Bretthauer, and David N. McNelis
Radiological Research Program
Western Environmental Research Laboratory
ENVIRONMENTAL PROTECTION AGENCY
Published September 1971
This research was performed as a part of the Radiation
Effects Program and was supported by the
U. S. ATOMIC ENERGY COMMISSION
under
Memorandum of Understanding No. SF 54 373.
-------
This report was prepared as an account of work sponsored
by the United States Government. Neither the United States
nor the United States Atomic Energy Commission, nor any of
their employees, nor any of their contractors, subcon-
tractors, or their employees, makes any warranty, express
or implied, or assumes any legal liability or responsibility
for the accuracy, completeness or usefulness of any infor-
mation, apparatus, product or process disclosed, or repre-
sents that its use would not infringe privately-owned rights.
Available from the National Technical Information Service,
U. S. Department of Commerce,
Springfield, VA. 22151
Price: paper copy $3.00; microfiche $.95.
on
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SWPHL-85r
Radionuclide Studies with Dairv Cows
Following Two Plowshare Experiments.
by
Stuart C. Black, Erich W. Bretthauer, and David N. McNeils
Radiological Research Program
Western Environmental Research Laboratory*
ENVIRONMENTAL PROTECTION AGENCY
Published September 1971
This research was performed as a part of the Radiation
Effects Program and was supported by the
U. S. ATOMIC ENERGY COMMISSION
under
Memorandum of Understanding No. SF 54 373.
*Formerly Southwestern Radiological Health Laboratory, part of the U.S.
Department of Health, Education, and Welfare, Public Health Service,
Environmental Health Service, Environmental Control Administration,
Bureau of Radiological Health.
-------
ABSTRACT
Baled hay was placed on the ground in the predicted trajectory of
the effluent from the two Plowshare cratering tests, Cabriolet and
Buggy. After contamination, the bales were collected and measured
amounts of the hay were fed to groups of dairy cows.
As compared to similar experiments following other cratering tests,
the amount of 131I transferred to milk was about one-third, and the
time to peak milk concentration and effective half-life in milk were
longer. The ratio of peak 131I concentration in milk to the peak
concentration in hay was also much less than that observed in previous
tests. These facts suggest that the 131I in the debris from these
two tests was less biologically available to the cow than it was in
previous tests.
For Pro.iect Buqqv, the transfer of 187W to milk was also measured.
Less than 0.5% of the tungsten ingested with the hay was secreted in
milk and the measured half-time in milk was about 2.5 days.
-------
TABLE OF CONTENTS
ABSTRACT i
LIST OF FIGURES iii
LIST OF TABLES iv
INTRODUCTION 1
EVENT DESCRIPTIONS 3
PROCEDURES 4
A. Cabriolet 4
B. Buggy 4
RESULTS 10
DISCUSSION 26
SUMMARY 30
REFERENCES 32
DISTRIBUTION
-------
LIST OF FIGURES
Figure 1. Station Locations for Project Cabriolet.
Figure 2. Station Locations for Project Buggy.
Figure 3. 131I Concentration in Milk for Cows Fed Hay from
Cabriolet Station A3.
Figure 4. 131I Concentration in Milk from Group I and Group II
Cows Fed Hay from Station 4.
Figure 5. 131I Concentration in Milk from Group III and
Group IV Cows Fed Hay from Station 2.
Figure 6. 133I Concentration in Cow's Milk Following Single
or Multiple Ingestion of Contaminated Hay.
Figure 7. 187W in Milk After Single (Group II) or Multiple
(Group I) Ingestion of Contaminated Hay.
Figure 8. 187W in Milk Following Single (Group IV) or Multiole
(Group III) Ingestion of Contaminated Hay.
Figure 9. 187W in Hay from Station 2 and Station 4, Buggy.
5
6
13
18
19
20
21
22
23
-------
LIST np TABLES
Table 1. Dairy Cow Grouos and Feeding Schedule. 8
Table 2. Average Hay Data, Groim 1 Cows, Project Cabriolet. 11
Table 3. Average Milk Data for Group 1 Cows, Project Cabriolet. 12
131
Table 4. Group Average Data for I in Hay, Project Buggy. 14
Table 5. Milk Data for Group I Cows, Project Buggy. 15
Table 6. Milk Data for Groups II and IV, Project Buggy. 16
Table 7. Milk Data for Group III Cows, Project Bugay. 17
131
Table 8. I and Other Data from the Cabriolet and
Buggy Stations. 25
Table 9. Forage and Milk Summary Data. 27
IV
-------
INTRODUCTION
The scheduling of two Plowshare tests, Cabriolet and Buggy, in the
early months of 1968 provided an opportunity to test a hypothesis
131
about I transfer in the forage-cow-milk chain. Studies of this
(1 2)
transfer during the TNT and Pin Stripe experimentsv ' ' produced
data which indicated certain differences in this transfer among
groups of cows. Since nearly all measurable parameters among the
groups of study cows were the same except for the filter/charcoal
activity ratio of air samplers in the area from which forage was
collected, then it was assumed that this ratio measured some factor
that was responsible for the observed difference. The filter/char-
coal ratio, as we interpret it, is a measure of the particulate/gaseous
make-up of the radioactive cloud; that is, if most of the radio-
activity in the cloud is attached to particles, then the air sample
will show more activity on the filter paper than on the charcoal and
the filter/charcoal ratio will be high. Therefore, the differences
noted in such parameters as the milk-to-forage ratio and percent
secreted in milk, among groups of cows fed forage contaminated by
different portions of a radioactive cloud, have been attributed to
the predominantly particulate or predominantly gaseous nature of the
radioiodine in that portion of the cloud.
To resolve this assumption, the experimental plan for Project Cabriolet
included stations located at various distances, both laterally and down-
wind of the predicted trajectory for the cloud. After the event, the
-------
cloud traveled more westerly than predicted so only one station
received sufficient deposition for this study. Because of this,
the plan for Project Buggy was revised. All 13 stations for
Buggy were located on a single arc, approximately 10 miles from
surface ground-zero (SGZ). This insured that at least one station
would be on the hot-line and one station would be on the edge of
the cloud.
Several objectives were set for both of these studies, but the
primary ones were to obtain:
(1) Correlations between filter/charcoal measurements in the
cloud and transfer of radioiodine in the forage-cow-milk system;
(2) Correlations between surveillance data and peak milk
concentration that may be useful for predictive estimates;
(3) Comparisons between single and multiple ingestion of hay
contaminated at the same location.
-------
EVENT DESCRIPTIONS
Project Cabriolet was a nuclear experiment in hard, dry, rhyolite
rock executed as a part of the Plowshare Program for development of
nuclear excavation. Cabriolet was detonated on 26 January 1968
at approximately 0800 (PST), in Area 20, Nevada Test Site(NTS). The
resultant yield was 2.3 +0.5 kt, and emplacement deoth was 170.75 feet.
Project Buggy was the first nuclear row-cratering detonation executed
as part of the Plowshare Program for development of nuclear excavation
techniques. Five nuclear explosives, each with a yield of 1.1 kt,
were detonated simultaneously at 0904 (PST), 12 March 1968. The
depths of burst were at 135 feet, and the spacing between explosives
was 150 feet. The experiment took place on Chukar Mesa, Area 30,
Nevada Test Site in a dry, complex basalt formation.
-------
PROCEDURES
The procedures for each of the events were similar, and the stations
were equipped in a similar manner. The station locations for Cabriolet
are indicated on Figure 1. The fixed stations are indicated by
triangles while the circles indicate possible locations of mobile
stations which were to be moved to intercept the cloud following
detonation. There were two mobile stations on both Arcs B and C.
For Buggy, 13 stations were placed on a single arc approximately ten
miles from SGZ, as shown in Figure 2. The items located at those
stations and used for the dairy cow experiments are listed below
for each event.
A. Cabriolet
Only one station had a, sufficiently high deposition for use, i.e.,
Station A3 (2.8 miles @ 355° from SGZ). The following equipment
and materials were available:
1. Baled alfalfa hay - 17 bales with one bale having an 11.4-cm
planchet centered on each exposed surface;
2. A monitoring system which telemeters ion chamber and meteorological
data;
3. Tempest, Staplex and special air samplers;
4. Fallout trays and planchets;
5. A precipitation collector.
B. Buggy
The cloud hot-line passed near Station 4 (10 miles @ 356° from SGZ),
which was used for study. Station 2 (10 miles @ 345° from SGZ) was
selected to study any edge effects. Both stations were equipped
as follows:
1. Baled alfalfa hay - 18 bales with one bale having an 11.4-cm
planchet on each exposed surface;
2. Fallout trays and planchets;
-------
MOUNTAINS
STANDARD /,
PASS
|345C
GOLD
FLAT
20 MILES
330°
ARC C
ARC B
Fig. 1 - Station locations for
Project Cabriolet.
\
MILES
ARC A U2QL
FIXED STATION
POSSIBLE LOCATIONS FOR MOBILE STATIONS
-------
17
I
I Mercury
Highway
Buckboard
Mesa Road
. -I
•1
2 - Station locations for
Project Buggy.
-------
3. Two air samplers (10 cfm, microsorban or Whatman 541 prefilter
and MSA charcoal cartridge);
4. Meteorological instruments for wind direction and speed;
5. Glass microscope slides for particle size measurement.
In both studies, the individual hay bales were spaced one meter apart
on the ground to maximize deposition on the hay. After cloud passage
the hay was transported to the ERA dairy farm, in Area 15 of the Nevada
Test Site, and fed to selected groups of cows according to the schedule
shown in Table 1. For each feeding, the hay was placed in a plastic
tub, weighed, counted and offered to the cow after each milking. When
the cow had finished eating, the tub was removed, weighed and counted
again. Counting was done by placing the tub on a turnstile and rotating
it in front of a shielded 10-cm Nal(Tl) crystal with a 200-channel
analyzer. Further, an aliquot of each hay bale was compressed into a
standard 400-ml container and analyzed by use of a 200-channel analyzer
and 10-cm Nal(Tl) crystal system as a check on the rotating tub system.
Groups II and IV, in the Buggy experiment, were given only one feeding
of hay to simulate the situation where hay is in the feed bins during
cloud passage but non-contaminated hay is fed thereafter. The reduction
in human hazard can then be estimated by comparing the total milk secretion
of the radioisotopes between the groups xjiven single or multiple feedings
of contaminated hay.
All other samples were counted on a 10-cm Nal(Tl) crystal with 200-
channel analyzer and the resulting spectra resolved by a least squares
method.
The hay bale at each station having an 11.4-cm planchet on each exposed
surface was used to correlate planchet deposition with deposition on
the bale. The deposition on each exposed surface of the bale was
2
estimated by the pCi/m measured on the appropriate planchet multiplied
by the surface represented and the resulting five values summed.
-------
Table 1. Dairy Cow Groups and Feeding Schedule
Group Cow No.
I 13
18
71
84
I 13
18
35
84
II 19
27
83
87
III 11
44
46
86
IV 21
26
43
85
Milk Output
Liters/ day
21.8
24.1
14.0
20.4
15.9
27.3
18.6
15.0
15.0
13.6
30.4
27.7
29.5
15.0
13.2
12.7
23.2
13.2
20.4
26.4
Fed Hay from
Station Feeding Schedule*
Cabriolet
7.5 kg given twice
daily for eight days
starting at 1600 hr.
A3 on 1/27/68
Buggy
7.5 kg given twice
daily for eight days
-, starting at 1600 hr.
* on 3/13/68
7.5 kg given as single
feeding at 1600 hr.
on 3/13/68
4
7.5 kg given twice
daily for eight days
2 starting at 1600 hr.
on 3/13/68
7.5 kg given as single
feeding at 1600 hr.
on 3/13/68
2
*The nominal weight was 7.5 kg/feeding but the actual weight varied
among the cows.
8
-------
When divided by the weight of the bale, the sum gives the concen-
tration in that bale which can then be compared to the concentrations
measured in the other 16 bales. If the correlation is satisfactory,
this procedure would replace forage sampling with its attendant
inaccuracies.
The particles deposited on the microscope slides were sized by using
an optical microscope with an eyepiece reticule. The size was
expressed as the count-median-diameter (CMD) based on the Feret
diameter measurements.
The cows in each group were milked on the normal twice-daily schedule
(approximately 0600 and 1500). The individual milk samples were
counted in a 3.5-liter Marinelli beaker. Analysis of other cow feed
and water as well as milk from control cows indicated that the contaminated
hay was the only significant source of radioactivity for the cows in
these studies.
-------
RESULTS
Of the hay collected from the four selected stations following
Cabriolet, only that collected from station A3 produced detectable
amounts of 131I in milk when fed to cows. The 131I activity in the
hay actually consumed by the cows is shown in Table 2. These data
are the average for four cows. The least squares line through the
plotted hay data indicates that the effective half-life (T «) of
radioiodine on this hay was 6.2 days.
The average 131I data on the milk from these cows are shown in Table 3
and plotted in Figure 3. The least squares lines in Figure 3 indicate
that the measured half-time in milk during feeding of the contaminated hay
was 11.1 days which changed to 1.1 days after cessation of intake.
The average data for the 131I in hay contaminated during Project
Buggy are shown in Table 4. Groups I and II cows were fed hay from
Station 4 and GrouosIII and IV cows were fed hay from Station 2. The
effective half-life for deposited 131I was 6.67 days for Station 4
hay and 6.79 days for Station 2 hay.
The group average data for 13-I in milk are shown in Tables 5-7 and are
plotted in Figs. 4 and 5. The levels in milk during feeding of
contaminated hay continued to rise so a half-time was not calculated.
Possible reasons for this effect are discussed later. The T ^ in milk
eff
after feeding ceased is indicated in the figures and, in both cases,
the T -f following a single feeding was shorter than that after multiple
feeding of hay from the same station.
The group-average data for 133I and 187W concentrations in milk are also
shown in Tables 5-7 and are plotted in Figs. 6-8. The T ff in milk,
as derived by least squares analysis, is also shown in the figures for
each group of cows. The data for 187W concentration in hay are
plotted in Figure 9.
in
-------
Table 2. Average hay data, Group 1 cows, Project Cabriolet
Date
1968
1/27
1/28
1/29
1/30
1/31
2/1
2/2
2/3
2/4
Time
1600
0830
1600
0830
1600
0830
1600
0830
1600
0830
1600
0830
1600
0830
1600
0830
Hay Ingested
kg
6.93
5.18
5.66
5.27
4.66
4.99
6.46
5.10
6.28
5.19
6.38
4.31
7.33
5.08
6.03
4.62
Total nCi
Ingested
417
284
207
270
202
167
298
164
66
156
185
77
300
257
143
127
131I Cone.
nCi/kg
60.2
54.8
36.6
51.2
43.3
33.5
46.1
32.2
10.5
30.0
29.0
17.9
40.9
50.6
23.7
27.5
11
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Table 3. Average milk data for Group I cows, Project Cabriolet
Date Collection Time I in Milk Production To1
1968 Time days* pCi/l iter I iters nCj_
1/28
1/29
1/30
1/31
2/1
2/2
2/3
2/4
2/5
2/6
0732
1557
0734
1619
0724
1549
0942
1549
0734
1557
0734
1557
0749
1630
0749
1619
0708
1704
0700
0.65
1 .00
1 .65
2.01
2.64
2.99
3.73
3.99
4.65
5.00
5.65
6.00
6.66
7.02
7.66
8.01
8.63
9.04
9.62
301
455
547
561
519
513
466
536
467
457
427
424
438
455
377
436
286
238
158
11 .8
•6.1
12.0
5.9
11 .0
6.3
13.5
5.6
11 .5
7.9
12.5
6.3
11 .9
6.9
11 .9
6.4
10.4
7.3
11 .2
3.55
2.78
6.56
3,31
5.71
3.23
6.29
3.00
5.37
3.61
5.34
2.67
5.21
3.14
4.49
2.79
2.97
1 .74
1 .77
*in days following initial feeding (1.33 days or 32 h. after event).
12
-------
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Table 4. Group average data for 131I in hay, Project Buggy.
Group 1
Group III
Date
3/13
3/14
3/14
3/15
3/15
3/16
3/16
3/17
3/17
3/18
3/18
3/19
3/19
3/20
3/20
3/21
Time
1600
0715
1600
0730
1600
0800
1600
0830
1600
0730
1600
0830
1600
0800
1600
0800
Hay
Ingested
kg
8.48
7.37
9.28
6.93
6.92
5.51
7.94
6.71
8.91
7.14
7.94
7.31
8.64
6.47
8.91
6.77
Group II
Total
Intake
yCl
1.45
1.07
3.98
1.55
1.75
1.07
1.88
1.47
2.12
2.01
1.37
1.66
1.96
1.14
0.84
0.12
Hay
Ingested
kg
8.87
8.08
7.17
6.30
6.88
5.50
6.98
7.04
8.63
7.37
7.54
7.14
8.38
7.08
10.06
7.01
Group IV
Total
Intake
yCi
0.13
0.09
0.31
0.29
0.38
0.24
0.37
0.33
0.21
0.25
0.23
0.17
0.32
0.21
0.22
0.19
3/13
1600
7.17
0.09
7.19
0.14
14
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Table 5. Milk data for Group I cows, Project Buggy
Date
1968
3/14
3/15
3/16
3/17
3/18
3/19
3/20
3/21
3/22
3/23
3/24
3/25
3/26
3/27
Collection
Time
days*
0.66
0.99
1.66
1.99
2.66
2.99
3.66
3.99
4.67
4.99
5.67
6.02
6.67
6.89
7.65
8.01
8.64
9.01
9.65
10.01
10.65
11.01
11.65
12.01
12.64
13.02
13.65
Avg. Milk
Production
liters
10.9
6.0
11.4
4.6
13.0
5.9
12.0
4.7
12.1
6.5
10.3
5.0
10.8
7.5
11.4
6.9
10.6
6.7
10.8
7.9
11.2
6.1
11.1
6.3
12.0
7.1
11.6
I3ir
nCi /liter
0.73
0.88
1.58
1.99
1.83
2.15
1.79
2.27
2.03
2.54
2.76
2.40
2.18
2.38
2.02
2.43
1.45
1.11
0.66
0.39
0.22
0.16
0.10
0.08
0.05
0.05
0.04
133j
nCi/liter
5.06
4.52
3.79
3.51
1.89
1.62
0.97
0.96
0.53
0.60
0.37
0.30
0.17
187W
nCi/liter
1.30
1.84
2.42
2.20
1.73
1.78
1.07
1.12
0.91
1.15
0.80
0.82
0.43
0.67
0.35
1.50
0.87
0.57
0.31
0.18
0.12
0.13
0.07
0.07
a 04
0.06
0.06
*Days after initial feeding which was given 31 hr. or 1.27 days after
detonation. J
15
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Table 6. Milk data for Groups II and IV, Project Buggy
Date
1968
3/14
3/15
3/16
3/17
3/18
3/19
3/20
3/14
3/15
3/16
3/17
3/18
3/19
Collection
Time
days*
0.64
0.97
1.64
1.97
2.64
2.97
3.64
4.01
4.64
5.01
5.64
5.98
?
0.63
0.96
1.63
1.96
2.63
2.96
3.64
4.01
4.64
5.01
5.64
5.98
Avg. Milk
Production
liters
Group II
12.9
6.4
11.8
6.8
13.2
7.6
12.5
5.8
12.5
7.0
12.1
6.5
ND
ND
Group IV
11.8
6.4
13.1
5.6
12.3
7.2
11.5
5.9
13.0
7.3
11.8
6.2
131!
pCi /liter
Cows'
745
853
382
277
122
81
42
29
13
13
13
14
ND
ND
Cows
92
115
63
45
21
16
14
13
10
11
23
7.2
133J
nCi/ liter
4.76
3.42
0.81
0.43
0.20
0.090
0.024
0.016
0.644
0.455
0.129
0.053
0.018
0.027
187W
nCi/liter
1.86
2.77
1.01
0.69
0.21
0.18
0.17
Q10
0.051
0.058
0.026
0.227
0.367
0.150
0.150
0.035
0.058
0.032
0.048
0.017
0.100
0.039
*Days after initial feeding which was given 31 hr. or 1.27 days after detonation
16
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Table 7. Milk data for Group III cows, Project Buggy
Date
1968
3/14
3/15
3/16
3/17
3/18
3/19
3/20
3/21
3/22
3/23
3/24
3/25
3/26
Collection
Time
days*
0.65
0.98
1.65
1.98
2.65
2.98
3.65
3.98
4.65
4.98
5.65
6.00
6.65
7.01
7.64
8.00
8.63
9.00
9.64
10.00
10.64
11.00
11.64
12.00
12.63
13.01
Avg. Milk
Production
liters
10.0
6.0
10.6
6.2
10.8
5.0
10.2
4.7
10.8
5.8
10.1
4.7
9.1
5.6
10.3
6.0
9.3
6.1
9.5
5.7
9.3
4.5
9.4
5.4
7.3
3.9
131J
pCi/liter
80
182
248
293
326
399
315
428
392
456
491
517
482
538
483
548
327
278
132
93
53
41
32
26
16
11
133l
pCi/liter
585
771
602
525
351
317
211
165
98
100
41
30
187W
pCi /liter
205
352
400
336
322
338
217
262
165
166
149
127
105
70
306
232
224
70
91
84
44
27
19
33
46
*Days after initial feeding which was given 31 hr. or 1.27 days after detonation.
17
-------
-------
-------
Half-time =Ju6
Half-time = r3
I concentration in cow's milk following single or
multiple ingestion of contaminated hay.
-------
-------
Half-time = 2.6 d
-------
-------
The data collected by the use of air samplers, fallout planchets,
and GM type survey meters following each event are shown in Table 8.
The deposition velocity data indicate a higher particulate content
for the Buggy cloud at the experimental stations than for the
Cabriolet cloud. This is supported by the filter/charcoal ratio
of the air samplers. The filter/charcoal ratio is obtained by dividing
the prefilter activity by the charcoal cartridge activity and is an
estimate of the ratio of particulate to gaseous material in the
effluent cloud. The small particle size measured on the Buggy stations
suggests a large fraction of the cloud was composed of very fine
particulate material.
The hay I concentration as estimated by the planchets placed on
each exposed face of one bale is also shown in Table 8.
24
-------
Table 8. 131I and other data from the Cabriolet and Buggy stations.
Station
No.
A3
1
2
3
4
5
Peak
Y@lm
mR/h*
31
20
64
280
252
3
1 . j._ j — TT
Planchet
Deposition
uCi/m2
1.04
0.66
3.08
19.4
18.2
0.17
Integrated Air
Hayt Concentration
nCi/kg yCi-s/m3
CABRIOLET
34 4.96
BUGGY
11.1
62 7.9
31.4
315 52.0
, IT — • — - ' •• -
Deposition
Velocity
cm/s
0.21
5.93
38.8
61.8
35.0
Filter to
Charcoal
Ratio
1.43
34.8
6.6
7.6
14.6
CMD**
pin
<0.6
<0.6
<0.6
<0.6
0.6
tHay concentration from planchets placed on the bale.
**Count median diameter.
25
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DISCUSSION
Some of the radioiodine results from these studies vary significantly
from the results of other similar studies we have conducted.
Of particular note are the long time until peak milk activity in the
Buggy study, the long T ff in milk in the Cabriolet study and the low
percent of ingested iodine which appears in milk in both studies.
These as well as other data derived from the experimental results are
shown in Table 9.
A suggested cause for these results is the lower biological availability
of radioiodine in the debris from the two events. This may have been
due to a stronger binding of the radioiodine to the particulate
material in the debris as compared to other events. The reasoning
behind these suggestions is rather straightforward. Note that in both
groups from Buggy receiving a single feeding of contaminated hay, the
peak activity in milk occurred in the second milking. In other single-
(5)
feeding experiments, ' the peak milk activity occurred in the first
milking after ingestion - when the first milking was at least 3-4
hours after ingestion. This implies that the radioiodine was
released very slowly from the debris and was not immediately available
as had been true in the previous studies. The slow release of
radioiodine and the long residence time in the cow's G.I. tract
(approximately 72 hours; also explain the low percent transfer to
milk and the longer effective half-life in milk. Further, the
relatively normal Tgff on hay (6.2 - 6.8 days) suggests that the hay
was not a major factor in these effects.
The 133I and 187W results from Project Buggy are somewhat similar
in indicating a lower biological availability for those radionuclides,
also. In a metabolism study/ ' a solution of Na2W04 was given to four
26
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Table 9. Forage and milk summary data
Measured
Parameter
Cabriolet Buggy Station 2
1311 131j 133J
Buggy Station
131J 133J
yCi/m2
yCi-s/
Peak mR/h
Hay Teff-days
1.04
4.96
31
6.2
3.08
7.9
64
6.8
0.85
18.2
52.0
252
6.7
0.77
Milk Teff-days
Time to Peak days
% in milk
Mi Ik/forage*
Peak nCi/liter
Milk half-time-days
Time to Peak-days
% in milk
Milk/forage*
Milk Teff after
feeding-days
Single ingestion data
0.
1.
2.
0.
68
0
8
0056
0.44
0.66
-
-
Multiple inqestion
0.56
11 ••
1.1
2.01
2.2
0.0093
0.
-
7.
55
0
0.77
1.2
1.0
1.4
0.01
0.
1.
0.
-
94
0
26
0.
1.
2.
0.
61
0
8
0068
0.
0.
-
40
66
0.
1.
0.
66
0
16
data
0.
2.
1.
0.
0.
40
6
7
34
0007
2.
5.
1.
0.
76
7
2
0064
5.
1.
0.
1
2
66
2
^- •
2
*- •
1.
0.
0.
4
4
^
7
12
0003
1.13
0.92
1.01
0.78
0.9T)
*Peak concentration in milk divided by peak concentration in hay.
27
-------
cows (as a single oral dose) and the secretion of tungsten in milk and
excreta measured. The results from that study indicate that the
biological half-time (in milk and blood) for 187W is 0.75 days - T^
of 0.42 days - and that the percent transferred to milk is 0.4. These
values are different from those in Table 9. Later, another group of
four cows was given twice-daily doses of 181W, as the tungstate,
for seven days. The percent in milk in the latter experiment was
0.64 and the peak milk concentration was 0.0005 times the activity
in the first dose. The higher percent in milk, compared to that in
Table 9, also suggests a lower biological availability of the tungsten
in the debris from Project Buggy.
Another possible reason for the long T „ in milk during ingestion of
the contaminated hay was the variation in intake. The data in Table 4
indicate only a small variation in total uCi intake during the 8 days
of feeding the hay. This was due to a combination of the amount
consumed and the activity concentration in the hay. The cows consumed
varying amounts at each feeding which would influence the activity
secreted in the milk. Also, the bales of hay were used in a pre-assigned
sequence and since the deposition on the bales was not uniform, it
was possible to feed a bale with a higher deposition at a later time than
one with a lower deposition.
An important prediction to be made after a release of radioactive
material is the peak 131I concentration to be expected in milk. This
prediction can be made rather promptly if surveillance data can be
correlated with the peak milk concentration. For Project Buggy, a
useful procedure is to take the ratio of the various parameters at
Station 4 to those at Station 2 and compare the ratios. The peak milk
ratio (Table 9) is 5.1 while the other ratios are: mR/h = 3.9, ^Ci/m2 = 5.9,
and yCi-s/m3 = 6.6. These three ratios would give good estimates of
28
-------
the relative peak milk concentrations at different locations con-
taminated by the same event. The absolute concentrations, though,
could not be predicted with any confidence as can be seen if the
Buggy surveillance data are used to estimate the peak milk concen-
tration obtained during the Cabriolet experiment. The extrapolation
from the rr,R/h data would estimate a peak milk concentration for
Cabriolet of 300 pCi/liter, from the air data would also estimate
300 pCi/liter, while from the MCi/m2 data would estimate only
160 pCi/liter. Thus the best estimate is about 1/2 the observed value.
There was no obvious difference in the milk transfer of radioiodine
between the two groups of cows in the Buggy experiment which could be
attributed to the difference in the filter/charcoal ratio at the
two stations. This may have been due to the large ratio at each
station as in one case 87% of the air sampler activity was on the
prefilter and in the other case 94% was on the prefilter. Such a small
difference in the filter/charcoal ratio may not be detectable in
biological sampling.
The planchets placed on each exposed surface of a hay bale, when
properly corrected, should yield data for estimating the concentration
in the hay. This was not necessarily true for any particular bale
from the 16 contaminated at each station, though the average for all 16
bales was reasonably close. The planchet estimate when divided by the
average concentration in all bales resulted in ratios which were 0.58,
1.0, and 1.2 for the Cabriolet and two Buggy stations, respectively.
The planchet on top of the bale, however, when used as the sole means
of estimation, seriously under-estimates the hay concentration so it is
useful merely in establishing the relative contamination of forage. This
effect may have been due to the close-in location of the experimental
stations where the major portion of the deposition was probably not on
top of the bales.
29
-------
SUMMARY
Hay, contaminated by the effluent from the Cabriolet and Buggy
cratering events, was fed to groups of dairy cows in controlled
ingestion experiments. Air sampling, survey meter, and deposition
data were also collected at the locations where the hay was
contaminated. The principal objectives of the experiments were
to detect any differences in the forage-cow-mi Ik transfer of
131I which might be due to the varying particulate/gaseous mix
in the effluent clouds and to search for correlations between
surveillance data and milk levels.
Of the ten possible stations set out for Cabriolet, only one
received sufficient activity for useful study, but Project Buggv
contaminated several stations of which two were used for ingestion
studies. For Project Cabriolet, the hay was fed twice daily for
eight days to a group of four cows. For Project Buggy, one
feeding of hay was given to one group of cows while twice-daily feeding
of hay from the same station was offered to another group of cows
for eight days. This was also done with the hay from a second
station.
The particulate/gaseous ratio was sufficiently large at both
stations, for Buggy, that no detectable difference occurred in the
forage-cow-milk transfer of 131I. The best surveillance data for
predicting peak milk concentrations were the integrated air
concentration (yCi-s/m3) and the peak gamma mR/h measured at 1 m above
ground. However, both parameters predicted only 50% of the observed
peak milk value in the Cabriolet experiment.
In both experiments, the biological availability of 131I apparently
was less than had been observed in previous experiments. Less than
3% of the ingested 131I appeared in milk, and both the Teff and time to
30
-------
reach the peak milk concentration were longer than was observed in
other similar studies. Furthermore, the peak milk/oeak forage
ratios were less than Q.01, much less than those found previously.
In the Buggy experiment, it was also possible to obtain some
forage-milk transfer data for 187W. Though the187W in hay was
10 times that of 131I, less than 0.5% appeared in the milk and
the half-time in milk was only about 2.5 days.
The single feeding experiments for Buggy, when compared to the
multiple intake experiments, indicate that multiple ingestion
yielded peak milk concentrations that were 3.2 and 4.8 times those
from single ingestion and the total 131I in milk was 13 and 15
times that following single ingestion. Thus the hazard to humans
drinking milk would be markedly reduced if the cows consumed only
the hay contaminated in their bunkers during cloud passage and were
then fed hay that had been covered at that time.
The low percentage of ingested radioiodine which was secreted in milk
in these two Plowshare tests has an important bearing on the potential
human hazard which may result from events of this type. Since the
reduced peak concentration and reduced total content in milk will
result in a lower thyroid concentration in humans drinking the milk,
the thyroid dose will be proportionately reduced. This will be offset,
to some extent, by the longer measured half-time in milk.
31
-------
REFERENCES
S. C. Black, D. S. Barth, R. E. Engel and K. H. Falter,
Radioiodine studies following the transient nuclear test (TNT)
of a KIWI reactor, Southwestern Radiological Health Lab. Report
SWRHL-26r, Las Vegas, NV (1969).
D. S. Barth, R. E. Engel, S. C. Black and W. Shimoda, Dairy
farm radioiodine studies following the Pin Stripe Event of
April 25, 1966, Southwestern Radiological Health Lab. Report
SWRHL-41r, Las Vegas, NV (1969).
S. C. Black, R. E. Engel, D. S. Barth and V. W. Randecker,
Radioiodine studies in dairy cows following the Palanquin event.
Southwestern Radiological Health Lab. Report PNE-914F,
Las Vegas, NV (1970).
R. E. Stanley, S. C. Black and D. S. Barth, 131I dairy cow
studies using a dry aerosol, Southwestern Radiological Health
Lab. Report SWRHL-42r, Las Vegas, NV (1969).
W. Sh'imoda, S. C. Black, K. H. Falter, R. E. Engel and D. S. Barth,
Study of a single dose 131I - 126I ratio in dairy cows, Southwestern
Radiological Health Lab. Report SWRHL-27r, Las Vegas, NV (1970).
A. Mullen, E. W. Bretthauer and R. E. Stanley, Excretion of
radiotungsten by the dairy cow. Presented at the American Chemical
Society Annual Meeting, Chicago, IL (1970).
32
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DISTRIBUTION
1 - 20 WERL, Las Vegas, Nevada
21 Robert E. Miller, Manager, NVOO/PEC, Las Vegas, Nevada
22 Robert H. Thalgott, NVOO/AEC, Las Vegas, Nevada
23 Thomas H. Blankenship, NVOO/AEC, Las Vegas, Nevada
24 Henry G. Vermillion, NVOO/AEC, Las Vegas, Nevada
25 Donald W. Hendricks, NVOO/AEC, Las Vegas, Nevada
26 Elwood M. Douthett, NVOO/AEC, Las Vegas, Nevada
27 Oared J. Davis, NVOO/AEC, Las Vegas, Nevada
28 Ernest D. Campbell, NVOO/AEC, Las Vegas, Nevada
29 - 30 Technical Library, NVOO/AEC, Las Vegas, Nevada
31 Chief, NOB/DNA, NVOO/AEC, Las Vegas, Nevada
32 Joseph J. DiNunno, Office of Environmental Affairs, USAEC, Washington, D.C.
33 Martin B. Biles, DOS, USAEC, Washington, D.C.
34 Roy D. Maxwell, DOS, USAEC, Washington, D.C.
35 Assistant General Manager, DMA, USAEC, Washington, D.C.
36 Gordon C. Facer, DMA, USAEC, Washington, D.C.
37 John S. Kelly, DPNE, USAEC, Washington, D.C.
38 Fred J. Clark, Jr., DPNE, USAEC, Washington, D.C.
39 John R. Totter, DBM, USAEC, Washington, D.C.
40 John S. Kirby-Smith, DBM, USAEC, Washington, D.C.
41 L. Joe Deal, DBM, USAEC, Washington, D.C.
42 Charles L. Osterberg, DBM, USAEC, Washington, D.C.
43 Rudolf J. Engeltnann, DBM, USAEC, Washington, D.C.
44 Philip W. Allen, ARL/NOAA, Las Vegas, Nevada
45 Gilbert J. Ferber, ARL/NOAA, Silver Spring, Maryland
46 EPA^wIshingtonfo?^' AsS1'Stant Admini*trator for Research & Monitoring,
47 oosepn «. Lieuei-inan, ueput.y assistant Adminictvatnv. for Radiat-jon ProqramSj
Of
48 Paul T. Tompkins, Act.Dir., Div. of Criteria & StanriavHc
n-, J •;-,-I--i i-i n Dvnnvamc CDA Dm^l,,,-;Tl_ 11 -i . ^ »
-------
Di stribution(continued)
49 - 50 Charles L. Weaver, Act.Dir., Div. of Surveillance ft Inspection, Office
of Radiation Programs, EPA, Rockville, Md,
51 Ernest D. Harward, Div. of Technology Assessment, Office of Radiation
Programs, EPA, Rockville, Maryland
52 William A. Mills, Act.Dir., Div. of Research, Office of Radiation
Programs, EPA, Rockville, Maryland
53 Bernd Kahn, Radiological Engineering Lab., EPA, Cincinnati, Ohio
54 Paul De Falco, EPA Regional Administrator, P.eqion IX, San Francisco, Calif.
55 Eastern Environmental Radiation Laboratory, EPA, Montgomery, Alabama
56 William C. King, LLL, Mercury, Nevada
57 Bernard W. Shore, LLL, Livermore, California
58 James E. Carothers, LLL, Livermore, California
59 Roger E. Batzel, LLL, Livermore, California
60 Howard A. Tewes, LLL, Livermore, California
61 Lawrence S. Germain, LLL, Livermore, California
62 Paul L. Phelps, LLL, Livermore, California
63 William E. Ogle, LASL, Los Alamos, New Mexico
64 Harrv J. Otway, LASL, Los Alamos, New Mexico
65 George E. Tucker, Sandia Laboratories, Albuquerque, New Mexico
66 Wright H. Langham, LASL, Los Alamos, New Mexico
67 Harry S. Jordan, LASL, Los Alamos, New Mexico
68 Arden E. Bicker, REECo., Mercury, Nevada
69 Clinton S. Maupin, PEECo., Mercury, Nevada
70 Byron F. Murphey, Sandia Laboratories, Albuquerque, New Mexico
71 Melvin L. Merritt, Sandia Laboratories, Albuquerque, New Mexico
72 Richard S. Davidson, Battelle Memorial Institute, Columbus, Ohio
73 R. Glen Fuller, Battelle Memorial Institute, Las Vegas, Nevada
74 Steven V. Kaye, Oak Ridge, National Lab., Oak Ridge, Tennessee
75 Leo K. Bustad, University of California, Davis, California
76 Leonard A. Sagan, Palo Alto Medical Clinic, Palo Alto, California
77 Vincent Schultz, Washington State University, Pullman, Washington
78 Arthur Wallace, University of California, Los Angeles, California
79 Wesley E. Niles, University of Nevada, Las Veqas, Nevada
80 Robert C. Pendleton, University of Utah, Salt Lake Citv, Utah
-------
Distribution(concluded)
81 William S. Twenhofel, U.S. Geological Survey, Denver, Colorado
82 Paul R. Fenske, Teledyne Isotopes, Palo Alto, California
83 - 84 DTIE, USAEC, Oak Ridge, Tennessee (for public availability)
85 W. E. Stocum, Group H-8, LASL, Los Alamos, New Mexico
86 John M. Ward, President, Desert Research Institute, University of Nevada,
Reno, Nevada
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