SWRHL-56r
PROTECTIVE ACTION TAKEN AT SCHOFIELD'S DAIRY
                HIKO, NEVADA
     FOLLOWING AN ACCIDENTAL RELEASE OF
   RADIOACTIVITY FROM THE NEVADA TEST SITE
                    by
      John S. Coogan and Wayne A. Bliss
  Western Environmental Research Laboratory

        ENVIRONMENTAL PROTECTION AGENCY
            Pub I ished January  I 972
This study performed under a Memorandum
        Understanding (No. SF 54 373)
                  for the
       U. S. ATOMIC ENERGY COMMISSION
of

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Energy Commission, nor any of their employees, nor any of  their contractors,
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or assumes any  legal  liability or responsibility for the accuracy, or process
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rights."
      Available from the National Technical  Information Service,
                   U. S. Department of Commerce
                       Springfield, VA 22151

              Price:  paper copy $3.00; microfiche $.95.
    ObG

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                                                                          SWRHL-56r
             PROTECTIVE ACTION TAKEN AT SCHOFIELD'S DAIRY
                             HIKO, NEVADA
                  FOLLOWING AN ACCIDENTAL RELEASE OF
                RADIOACTIVITY FROM THE NEVADA TEST SITE
                                   by
                   John S. Coogan and Wayne A. Bliss
              Western Environmental  Research Laboratory*

                    ENVIRONMENTAL PROTECTION AGENCY
                        Published January 1972
              This study performed under a Memorandum of
                     Understanding (No. SF 54 373)
                                for the
                    U. S. ATOMIC ENERGY COMMISSION
*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.

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                                INTRODUCTION
Protective Action Guide is a term often cited in health physics with consider-
ation to public exposure,  but applied protective actions have been few. Any
protective action is unique with respect to the many possible influences.  This
report defines a protective measure applied to decrease radioiodines in a
dairy's milk production and the factors judged in choosing the mode of action.
This action by the Western Environmental Research Laboratory (WERL) in concur-
rence with the Atomic Energy Commission was taken at levels below the Federal
Radiation Council guides and, although  intended primarily as a feasibility study,
was a prudent measure for minimizing the potential  thyroid dose.
On April 25, 1966, an underground nuclear test conducted at the Nevada Test
Site released radioactivity to the atmosphere.  Weather conditions were such
that the effluent traveled from the Nevada Test Site in a northeasterly direc-
tion.  Levels of radioactivity detected by portable instrumentation in the
immediate off-site area on the day of the test were low.  The maximum exposure
rate  in the off-site area was 8 mR/h, 42 miles from surface ground zero in an unpopu-
lated area.  The highest exposure rate  in a populated area was 1.5 mR/h at
Hiko, Nevada, 63 miles from surface ground zero in  Pahranagat Valley.
Milk  samples were collected  in the Pahranagat Valley where family milk cows and
dairy operations were present.  In addition to milk samples, other environ-
mental  samples were collected simultaneously:  natural  vegetation, field forage,
green chop, dry  hay- grain, water, air and soil.  Environmental samples were
collected once daily with the exception of milk which was collected twice daily
after the morning and evening milkings. All samples were immediately taken
to the  WERL  in Las Vegas, Nevada, for laboratory analysis.
All samples were analyzed on systems using a 4- by 4-inch Nal(Tl) crystal coupled
to a  400-channel pulse neight analyzer.  Results are reported in pCi/l for milk
or pCi/kg for vegetation.
Of  the milk samples collected in the Pahranagat Valley, those from Schofield's
Dairy at Hiko showed the highest concentrations of I3II.  The location with
the second highest concentration was about three-fourths of that observed from
Schofield's Dairy; however, this sample was from a family cow, the entire pro-
duction of which was utilized for sampling purposes.  This report  is concerned
only with circumstances involving Schofield's Dairy.
                                     I

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                           RADIOLOGICAL SITUATION

Table I lists the initial radioiodine levels through the maximum observed
following contamination at Schofield's Dairy.  These samples were composites
from cows of the main dairy herd.

Table I.  Radioiodine Levels in Milk From Schofield's Dairy
Date and Time
Col lection
4-25
4-26
4-26
4-27
4-27
of
PM
AM
PM
AM
PM
I3lj
320
1,900
3,300
4,400
4,800
pCi/1
I32j
	
490
3,100
1,100
1,900
I33j
1,000
6,100
20,000
15,000
12,000
I35j
800
4,300
1 1 ,000
2,500
1 ,000
 Field  forage samples for the same  location gave the following values  (Table
 2).  The  dairy  herd was not eating this vegetation but  it should serve as
 a  reference parameter  in more areas than green chop (freshly cut growing
 alfalfa and wheat).

 Table  2.   Radioiodine  Levels  in Field Forage From Schofield's Dairy
Date of Col lection
4-25
4-25
4-26
4-26
I3IT
120,000
460,000
140,000
85,000
I32T T
Tel
320,000
580,000
150,000
85,000
pCi/kg
I33T
310,000
580,000
300,000
160,000
I35j
220,000
390,000
48,000
27,000
 Schofield's  Dairy  was  feeding  green chop and grain exclusively  to  its  one
 hundred  and  thirty-eight  producing cows.  The  dairy  was  producing

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 approximately  650 gallons of  milk per day  which  was transported to a Las
'Vegas  processing  plant  at two-day intervals.
 Various  means  of  determining  whether radiation  levels violate established
 guides have  been  proposed.  However,  the most important consideration in
 any  situation  of  this sort is that radiation  exposure should  always be kept
 at a mi nimum level.
 Initial  concentrations  of radioiodine in milk from Schofield's Dairy were low.
 Past experience  indicated that the maximum concentrations in  milk would  be
 reached  at about  five days after  contamination.   The levels of    I on field
 forage pointed toward relatively  high   I concentrations in  the milk.   Data
 from past  radioactive releases have shown  that     I in milk will  reach a
 maximum  concentration of  0.015 to 0.15 times  the    I concentrations on  vege-
 tation.  This  indicated that  the  peak concentration of    I  in the mi Tk  would
 fall  in  the  range of 6,900 to 69,000 pCi/l.
 Ralph  A. James, University of California,  states a radiation  field produced
 by unfractionated  fission products of 0.032  mR/h  at H+24 hours is the  field
                                                      131   *
 corresponding  to  the FRC  upper limit for range  II of    !•
 An actual  gamma exposure  rate of  O.I  mR/h  was measured at Hiko 24 hours  after  the
 detonation.   Based on this measurement and James'  relationship, a concentration
                  131                                                         **
 of 8700  pCi/l  of     I  in  milk was estimated.   Referring to "the FRC Report #5,
 page II, "Deposition of  " I  can  vary greatly within a relatively small  geo-
 graphical  area.   As a result, there can be large differences  between    I concen-
 trations in  milk  produced on  farms only a  few miles apart."   Then the text goes  on
 to state,  "It  is  not possible to  predict  reliably the maximum concentrations of
 of     I  in milk  from deposition data."  The prior statements  are referenced
 not  to  discredit the   projected  dose  but to  point out the  uncertainty
  "Calculation of Radioactive Iodine Concentrations in Milk and Human Thyroid
 as a Result of Nuclear Explosions" Ralph A.  James, University of California,
 Lawrence Radiation Laboratory,  Livermore, California, February 14,  1964,
 Report #UCRL-77I6.
   From this measurement, greater than three times FRC Range II, that is,  more
 than 8700 pCi/l  of I3II in milk was projected.

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involved in projecting milk contamination from ground deposition data.

The Federal Radiation Council Report #5 states that from a single event
a total intake of 600 nanocuries of    I would result in a dose of about
10 rads to a two-gram thyroid.  It is estimated that a peak concentration in
milk of 60 to 70 nanocuries of    I per liter could result in such thyroid
doses.  The FRC does'not include approximately 20 to 25% of the infinite
thyroid dose which is obtained prior to the peak    I concentration.   It
is deduced then that a maximum concentration of 60 to 70 nanocuries
actually gives 12.5 to 13.3 Rad.  Chapter 0524, Standards of Radiation
Protection, U.S.  Atomic Energy Commission, gives 1.5 rem/year as a stand-
ard for thyroid dose to individuals of the population in an uncontrolled
area.   It  follows that 1.5 rem results from 6,800 to 8,400 pCi/l.
                           CONSIDERATIONS
These guides are based on FRC recommendations for exposure of the general
public  for normal peacetime operations.  Since Hiko is near the Nevada Test
Site, there was  no assurance that another exposure would not result within a
year.   Also, experience was needed  in the application of preventive action and
 its  effects on the dairy  herd, the  contaminant  levels, and the public.  The
 recommendation was made to the AEC  to take protective action.  The course of
 action  was chosen after considering the following:
      A.   The milk was being picked  up from the producer dairy and
          shipped to  Las Vegas, Nevada (at two-day intervals).  The
          milk was being processed and delivered to the consumers
          within  thirty-six hours after receipt by the pasteuriza-
          tion plant.  Dilution at the pasteurization plant could
          not have been greater than a factor of seven after pro-
          portioning  the milk  in the plant's bulk tanks.  The milk
          was not normally proportioned in the tanks and to do so
          would have  created inconvenience and expense to the
          processor.

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     B.   Disposing of  the  thirteen  hundred  gallons  of  milk would
         have  caused the processor  to  operate  below his  consumer
         commitments since no  other Grade A supply  was available
         for milk replacement.   Therefore,  disposal  of the milk
         was not a desirable protective  action  for  this  case.
     C.   Storage facilities for  this large  volume were non-existent
         thereby eliminating the possibility of decreasing the
         hazard through  radioactive decay.
     D.   Diversion of  the  contaminated milk to  milk products
         seemed a  likely procedure  which would  have allowed a
         large reduction of the  activity due to holding  time.
         This  possibility  was  discarded, however, because the
         producer would  receive  lower  prices for milk  which
         must  be diverted.  Furthermore, there  were no milk product
         processing  facilities in the  nearby area.
     E.   The  remaining possibility  was replacing the dairy's
         feed  supply.   This action  was chosen  as the most
         feasible  protective action to be taken, and it  is one
         of the actions recommended by the  FRC  for  reduction
         of human  exposure from  '^'l.   Intake  of the contaminant
         would be  cut  to a minimum  and contact  with any  persons
         other than  the producer would be unnecessary.  The only
         reduction  in  milk production  would come from  changing
         the cow's  feed.   Reimbursement  for this decrease would
         be small.   Replacement  hay was  available.   This course
         would also  yield  useful information as to  the effects
         of the protective action on the level  of  '3'l in milk.

                             PROTECTIVE  ACTION
The following  questions were  then posed  to  the dairy operator:
     A.   Would he  cooperate in feeding dry  hay if the  hay
         was  supplied  without  cost?

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     B.   What type and what amount of feed would be necessary?
     C.   How much, if any, hay was on hand at that time?
     D.   What time interval was necessary for the herd to be
         switched to dry feed?
     E.   What hay suppliers could he recommend?

The manager of Schofield's Dairy was most cooperative and immediately agreed
to switch to dry hay and grain as soon as it was available.   The nearest
supplier with suitable uncontaminated  hay was contacted and delivery was
made on April 27.  Dry feeding was initiated on the evening  of April  27.

A small  decrease of    I in the milk was seen on April 28 and this decrease
was quite marked by April  29.   Time was required for the clean feed to
purge the radioiodine already in the animals, but the following results
show that    I levels dropped by a factor of four within two days after
the feed change.

Table 3.  Radioiodine Levels in Milk Following Change to Dry Feed
Date and Time
Col lection
A- 9ft


A 9Q

of
AM

AM
PM

pCi/1
I3lj I32j I33j I35j
/ nnn — — f, 7nn 	 — —
T. 7nn 	 A 7nn 	
i Rnn i /inn
1 , 3UU — 1 , 4UU 	
i nnn — _ 7"^n 	 	 —

Four cows were fed the regular diet of green chop and grain as a control  to
assess the effect of the protective action.  The    I levels in their milk
decreased only about \0% per day.  The milk from these cows was not used
for human consumption.   The following graph depicts the trends seen in
both groups.   It  is estimated that this action reduced the    I thyroid
dose by 71%.  Schofield's Dairy continued to feed dry hay for 16 days,
time for 2-3 effective half-lives of    I to pass and acceptable levels of
   I to be reached.  The cows were then returned to their normal diet.

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                                       PIN STRIPE EVENT APRIL 25, 1966
                                          Schofield Dairy, Hiko, Nevada

                                      	I31I in Milk of Cows eating
                                         contaminated green chop (DecaycxT—O.7)

                                      	 131I in Milk of Cows after changing
                                         to uncontaminated hay   (Decay=xT—5.O)
                            4 cows remaining on
                              contaminated feed
 uncontaminated
  feed placed
before main herd

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                                 CONCLUSION

The initial  considerations of peak '^'l concentrations in vegetation at
Schofield's  Dairy pointed to maximum levels in milk about ten times higher
than those reached.   Using the James'  model relationship, the estimated
milk levels  were within about a factor of  two of  the measured peak level.

Two features become  paramount in handling  any situation where protective
action may be needed.   The first is  to sample all  possible sources which
may delineate and quantitate the contamination.   The second,  a quick assess-
ment of the  total  radiological  situation  is necessary before  employing pro-
tective action.

This paper has assessed a specific case which may  or may  not  be a precedent
for planning similar protective actions.   Any incident would  have to be
judged on the set of circumstances controlling its situation.   The para-
meters set forth here  are those used to judge this situation  and to deter-
mine the course of action taken.   Under different  circumstances, other
equally important issues may need  to be considered by the group responsible
for taking the necessary precautions.

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                              DISTRIBUTION

15   Western Environmental  Research Laboratory, Las Vegas, Nevada
16   Robert E.  Miller,  Manager,  NVOO/AEC, Las Vegas, Nevada
17   Robert H.  Thalgott,  NVOO/AEC, Las Vegas, Nevada
18   Henry G.  Vermillion,  NVOO/AEC, Las Vegas, Nevada
19   Robert R.  Loux,  NVOO/AEC,  Las Vegas, Nevada
20   Donald W.  Hendricks,  NVOO/AEC, Las Vegas, Nevada
21   Mail  & Records,  NVOO/AEC,  Las Vegas, Nevada
22   Chief, NOB/DASA,  NVOO/AEC,  Las Vegas, Nevada
23   Ernest D.  Campbell,  NVOO/AEC, Las Vegas, Nevada
24   Technical  Library,  NVOO/AEC,  Las Vegas, Nevada
25   Phi I ip W.  AI I en,  ARL/NOAA,  NVOO/AEC, Las Vegas, Nevada
26   Martin B.  Biles,  DOS,  USAEC,  Washington, D. C.
27   Ralph S.  Decker,  Safety Div., SNSO,  USAEC, Washington, D.C.
28   John P. Jewett,  SNSO-N, Jackass Flats,  Nevada
29   Assistant General  Manager,  DMA, USAEC,  Washington, D.C.
30   John A. Harris,  PI,  USAEC,  Washington,  D.C.
31   John S. Kelly,  DPNE,  USAEC, Washington, D.C.
32   Charles Bild,  Sandia Laboratories, Albuquerque, New Mexico
33   George E.  Tucker,  Sandia Laboratories,  Albuquerque, New Mexico
34   Chief, Weapons Test Div.,  DNA, Washington, D. C.
35   Bernard W. Shore,  LLL, Livermore, California
36   James E.  Carothers,  LLL, Livermore,  California
37   Roger E.  Batzel,  LLL,  Livermore, California
38   WilliamC. King,  LLL,  Mercury, Nevada
39   Howard A.  Tewes,  LLL,  Livermore, California
40   Lawrence S. Germain, LLL,  Livermore, California
41   L. Crooks, LLL, Mercury, Nevada
42   Harry J. Otway, LASL,  Los Alamos, New  Mexico
43   William E. Ogle, LASL,  Los Alamos,  New Mexico
44   Charles  I. Browne, LASL, Los  Alamos, New  Mexico

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     Distri but ion(continued)

     45    Harry S. Jordan,  LASL,  Los  Alamos,  New  Mexico
     46    Gilbert J.  Ferber, ARL/NOAA,  Silver Spring,  Maryland
     47    Stanley M.  Greenfield,  Assistant Administrator  for  Research  & Monitoring,
          EPA, Washington,  D. C.
     48    Acting Deputy Assistant Administrator for  Radiation Programs, EPA,
          RockviIle,  Maryland
     49    Paul C.  Tompkins, Acting Director,  Division  of  Criteria  & Standards,
          Office of Radiation Programs, EPA,  Rockvilie, Maryland
     50    Ernest D. Harward, Acting Director,  Division of Technology Assessment,
          Office of Radiation Programs, EPA,  Rockvi Me, Maryland
51  -  52    Charles L.  Weaver, Acting Director,  Division of Surveillance & Inspection,
          Office of Radiation Programs, EPA,  Rockvi Me, Maryland
     53    Gordon Everett, Director, Office of  Technical Analysis,  EPA,  Washington, D.C.
     54    Bernd Kahn, Chief, Radiochem. & Nuclear Engineering, NERC, EPA,  Cincinnati, 0.
     55    Richard S.  Davidson,  Battelle Memorial   Institute, Columbus,  Ohio
     56    R. Glen Fuller, Battelle Memorial  Institute, Las Vegas,  Nevada
     57    Arden E. Bicker, REECo, Mercury, Nevada
     58    Frank E. Abbott, USAEC, Golden,  Colorado
     59    John M.  Ward, President, Desert Research Institute, University of  Nevada, Reno
60 -  61    DTIE, USAEC, Oak Ridge, Tennessee

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