RADIOACTIVITY LEVELS IN THE
  ENVIRONS OF THE ROCKY FLATS
        PLUTONIUM PLANT

       Golden, Colorado

             1970
ENVIRONMENTAL PROTECTION AGENCY
     WATER QUALITY OFFICE
 DIVISION OF TECHNICAL SUPPORT
RADIOLOGICAL ACTIVITIES SECTION

       Cincinnati, Ohio

          April  1971

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                           TABLE OF CONTENTS
                                                              Page  No.
Introduction and Background  	       1




Liquid Waste- Management Practices	       3




Environmental Surveillance   	  	       3




Water Quality Office Study   .  >	      11




     Sampling Procedures	      11




     Analytical Procedures   	  ...      13




     Results	      16




Discussion  . .	    '28




Conclusions	..........      33



Reconrnendations .	      33





                              APIEHDIXES




Appendix  A




     Process Flo;/ Sheet	      35




Appendix  B




     Surveillance Information and Data   .  	    37-^2




Appendix  C




     Analytical Methods 	  	      4 3




          Gross Alpha Analyses	      ^3




          Total Alpha Radium  .  . '	      4 3




          Uranium .  '.	  ...........  .....  .      kk




          Strontium-r90	      Wi-




          Plutoniura	      kk




          Tritium.	      45

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                                                              PageNo.

Bibliography	.  .    kC-^1



                            LIST OF FIGURES
                                                              KollOW::
                                                              Paj;,;e  No_.

Fi:,:.ive 1   -  Sampling Stations	      '+

Fif.ure '.-   -  Dissolved Plutonium in Water   pCi/1   ....      20

Figure 3   -  Plutonium in Sediments   pCi/g   	      22



                            LIST OF TABLES
                                                              Page  Mo.

Table I    -  Liquid Radioactive Waste Disposal - July
              through December 1969 	      6

Table-II   -  Gross Alpha Activities in the Environs  of  the
              Rocky Flats Plant	      10


Table.Ill  -  Sampling Stations 	    13-1^


Table IV   -  Solids Concentrations in Water Samples   ...      17


Table V    -  Dissolved Radioactivity in Water Samples   .  .      18


Table VI   -  Radioactivity in Bottom Sediment Samples   .  .    22-23

Table VII  -  Broomfield Water Treatment Plant Samples   ...    26

Table VIII -  Radioactivity in Soil Samples ...  	      27

Table IX   -  Limiting Concentrations for Flutonium-239  and
              Uranium	  .      30
                                  ii

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Introduction and Background



       During the week of February 23, 1970, representatives of the Water



Quality Office visited the Rocky Flats Plant of the Atomic Energy Commis-




sion (AEC).  Located approximately 21 miles northwest of Denver, Colorado,



between Golden and Boulder, the facility is operated by the Dow Chemical



Company under contract to the AEC.  The purpose of the visit was to obtain



information on liquid radioactive waste management practices at the facility



and the environmental surveillance activities in the plant environs.  Cor-



respondingly, related discussions on the surveillance activities of the




State of Colorado were held with personnel of the Department of Health,



Division of Air, Occupational, and Radiation Hygiene.






       The Water Quality Office was represented by Dr. Milton W. Lammering



and Mr. Robert C. Scott, both of the Radiological Activities Section, Divi-



sion of Technical Support, Cincinnati, Ohio, and Mr. Thomas M. Carter,



Missouri Basin Region, Kansas City, Missouri.  In the discussions with per-



sonnel of the AEC and Dow Chemical Company, Mr. A. Hazle represented the



Colorado Department of Health, Division of Air, Occupational, and Radiation



Hygiene.






       Normal operation of the plant involving the production of plutonium



parts for nuclear weapons results in the release of small quantities of



plutonium to the environment via the liquid waste treatment system.  In addi-



tion to this controlled and regulated release mode, accidental plutonium




releases have occurred on three occasions:  a) a major fire in 1957,

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b)'leakage from a storage field of drums containing plutonium-aoutaminaUed




oil  (scne tine during 1955 through 1967), and c) a major fire on May 11,




Iyc9-  -"he last incident was the subject of a highly critical report ' by




tiie  subcommittee of the Colorado Committee for Environmental Information.




Following the release of the Committee's report, a rash of articles appeared




in the local news media on the public health implications of the May 11 fire




as-well as the general threat to public health and safety.posed by the con-




tinued operation of the plant.  Although WQO involvement was in response to




the  publicized controversy surrounding the plant, the evaluation by WQO per-




sonnel was limited to a review of liquid radwaste management practices and a




brief, but intensive, sampling program to determine plutonium levels in the




watercourse crossing the plant boundary and nearby lakes and reservoirs.




Evaluations' of the probabilities of future fires, explosions, and criticali'cy




accidents at the plant and the health hazards associated with such incident.s




are beyond the realm of the vested responsibilities and authority of the




Water Quality Office.






       A previous Federal inspection of waste disposal practices at the Rocky




Flats Plant was conducted on December 18, 1963, by Mr. Keith F. Chrisman,.a




sanitary engineer in Region VIII, Public Health Service, Department of Health.,




Education, and Welfare.  In recommending no need for remedial action, it wac




noted that the Colorado.State Department of Health had concluded that the




facility was not a source of detrimental water pollution.  The State's posi-




tion has not changed in the intervening years.

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       The following sections of this report pertain to the findings of



the February investigation.  Therefore, discussion of the environmental




levels of plutonium is limited to soil, water, and bottom sediment.  A



second report will cover the September 1970 study to determine the pluton-



ium levels in the aquatic biota inhabiting Great Western Reservoir and



Standley Lake and the general distribution of plutonium in the bottom sedi-



ment of Great Western Reservoir*






Liquid Waste Management Practices



       All material in the liquid waste effluents from the Rocky Flats Plant



ultimately reach Great Western Reservoir, a multiple-purpose reservoir with



a maximum storage capacity in excess of 3100 acre-feet.  Liquid radioactive



wastes, after dilution with treated sanitary sewage, flow through a system



of four small retention ponds connected in series.  The overflow from this



pond system flows down the south fork of Walnut Creek, and subsequently,



into Great Western Reservoir (refer to Figure l).  The mouth of Walnut Creek



is approximately four miles downstream from the outer plant boundary. Except



during the spring melt, flow into Great Western Reservoir from Walnut Creek



is comprised almost totally of liquid wastes from the plant.  Great Western



Reservoir is the public water supply source for the City of Broomfield.






       On-site discharges of liquid radwastes are made at several buildings



as indicated by the following list.

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       Building
Identification Number        Major Activity Carried Out in the Building


         kkk                 Handling of uranium-contaminated mate-rial.


         771                 Plutonium recovery . .


         77^                 Treatment facility for liquid radwastec


         7?6                 Holding tanks for laundry wastes from
                               Building 778- are located in this building


         779                 Laboratory


         88l                 Handling of uranium-contaminated material


          95                 Treatment facility for sanitary wastes


The disposal of liquid radwastes from Buildings kkk, 771, 776, 779, and S6l

is based on the results of chemical analyses of each batch.  Normally,

wastes from Buildings 771 and 779 are discharged to the drainage ditch

carrying wastes to the retention pond system at a point upstream from the

sewage treatment plant discharge.  Liquid wastes from Buildings bkk, 776

(laundry wastes), and 881 are mixed with raw sewage and pass through the

biological treatment process.  If, however, analysis of the waste batch

shows that a specific constituent(s) exceeds the concentration limit(s) for

discharge without treatment,  the batch is transferred to Building 77^ for

the required treatment.  For laundry wastes,  treatment is required if the

following limits are not met:

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                                                16
                                                     AUTREY RESERVOIR
          N
       U.S.  ATOMIC
   ENERGY COMMISSION
   ROCKY FLATS PLANT
                                               GREAT WESTERN RESERVOIR
                                         MOWER RESERVOIR
                                         11
I	
          FIGURE 1
     SAMPLING STATIONS
.14W
                                                                        14S     CALKINS
                                                                                 LAKE
                                0
                                i
4000      8000 FT.
o
     15
     *——


POMONA LAKE
                     J

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             Plutonium  -  3500 dpm/1 (approx.  1600 pCi/1)*

             Nitrate (NOj)  -  ^5 mg/1

             Hexavalent chromium  -  1.0 mg/1

Concentration limits for treated waste discharges from Building 77^;

presumably other "buildings, are the same as those cited above for laundry

wastes.  Waste volumes discharged to the drainage ditch and the sewage treat-

ment plant during the last half of 1969 and the corresponding amounts of

cross alpha activity are listed in Table I.


       Two basic processes are available for the treatment of liquid wastes:

1) chemical precipitation and sand filtration,  and 2) evaporation with the

water vapor vented to the atmosphere.  As shown on the detailed process flow

sheet (Appendix A), flexibility of operation exists within and between the

two processes.  In general, wastes classified as "high radioactivity - low

nitrate" wastes are processed by chemical precipitation and filtration,

analyzed on a batch basis, and discharged to the drainage ditch upstream

from the 'sewage treatment plant.  "High nitrate" wastes are evaporated.  How-

ever, due to the limited capacity of the evaporator, high nitrate wastes are

stored initially in a series of three asphalt-lined evaporation ponds for.

volume reduction.  Evaporative losses have been sufficiently great to prevent

a continuing increase in the volume of stored waste.  Sludge produced in the
   About one-third of the effluent limit for dissolved plutonium-239 as
   specified in 10CFR20,  Appendix B,  Table II.  Assuming the plutonium is
   totally.in.solution is conservative since the corresponding limit for
   insoluble plutonium is 30,000 pCi/1.

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                                           Table   I
                Liquid Radioactive Waste Disposal  -   July through December 1969
            Source
To drainage ditch from:

        Building 771

        Building 774

        Building 779
 Volume
(gallons^
   23,000

1,117,600

   91,400
 Gross Alpha
Radioactivity
  (curies)
  1.3 x 10

  1.4 x 10
                                            -k
  9.1 x 10
-3

-5
To sewage treatment plant from:

        Building 444

        Building 776

        Building 881
  146,500

1,137,200

  261,400
  1.9 x 10~3

  5.4 x 10"3
  2.4 x 10
          -3

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                                   7 '






(iucoiit.'uiiinution of liquid radwastec is drummed for off- cite burial at  the




Nut.ional Keactor Tenting Station (Idaho).






       The sewage treatment plant is an extended aeration facility with  a




chlorinated effluent.  Although the purpose of the plant is the  treatment




of non- radioactive sanitary wastes, some degree of decontamination of  the




radwastes from Buildings kkk, 7?6, and 88l is also achieved by the treatment




process.  The uranium- contaminated sludge from the digester is buried  in an




OTi-site landfill unless established radioactivity limits are exceeded.  In




the latter case, the sludge is drummed for shipment to the National Reactor




Testing Station.  The plant effluent also has a dilution effect  on wastes




discharged to the drainage ditch from Buildings 771> 77^; and 779-
       Although the system of ponds. receiving the combined plant effluent




was designed to provide retention of liquid wastes before entry into the




unrestricted environment, the ponds also function as a series of oxidation




ponds providing additional treatment of the organic-bearing wastes.  Simi-




larly, the luxurious algal growths undoubtedly . produce additional decon-




tamination of the plant wastes.  However, this reduction in the amount of




radioactivity released to the environment will not be realized on a long-




term basis if the ponds are scoured during periods of high run-off.  The




effluent from the pond system is sampled proportional to flow and com-




posited for analysis (gross alpha, nitrate, phosphate, fluoride, and hexa-




valent chromium) .  Gross alpha activity in the effluent is usually on the




order of 15:pCi/l which by inference indicates that plutonium releases are

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                                   8

                                               2
well below the operational limit of 1600 pCi/1.    Phosphate concentration

data for 1969 were as follows:


                      Maximum  -  38 mg/1 as FO^

                      Minimum  -  0.4 mg/1

                      Average  -  8.9 mg/1


Due to decontamination in the sewage treatment plant and retention ponds,

the net release of gross alpha activity to Walnut Creek during the last half
                                                         _0
of 1969 should have been less than the total of 11.3 * 10   curies shown in

Table I.


Environmental Surveillance

       Monitoring of environmental radioactivity levels in the environs of

the Rocky Flats Plant is conducted routinely by personnel of the Dow Chemical

Company.  Based on the semi-annual monitoring reports published in the U. S.

Public Health Service periodical, "Radiological Health Data and Reports," the

operational details of the surveillance program are the following:


Type of Sample             	Description	

     Air                   Continuous air samples are collected at Coal Creek
                           Canyon, Marshall, Boulder, LaFayette, Broomi'ield,
                           Wagner School, Golden, Denver, and Westminster.
                           Analyses of monthly composite samples are reported
                           as a single average concentration for all stations.

    Water                  Except during winter months, monthly samples are
                           collected from Baseline Reservoir, Great Western
                           Reservoir, Standley Lake, and Ralston Reservoir.
  Vegetation               Semi-annual collection; i.e., during one month of
                           each six month reporting period.  Samples are
                           analyzed in accordance with two collection zones;
                           less than four miles from the plant and four to
                         .  eighteen miles from the plant.

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                                    y






 Apparently  topsoil sampling has been  added to the  surveillance  program



 Liince  the Kay 11 fire.   Samples are analyzed for gross  alpha  activity



 which  includes naturally-occurring  radionuclides (uranium, thorium,  radiun,



 etc.)  as well as any  plutonium that might be present  as a  result  of  plant



 operation and/or atmospheric fallout.






        The  results of the monitoring  program for 1968 and  the first  half of



 1969 are shown in Table  II.   These  data do not  show any significant  increases



 in gross alpha levels above  natural background  in  the media sampled  as the



 result of plant operations  (including accidental releases).   Since there is




 no information to indicate  otherwise,  it is assumed that the  gross alpha



 results for water samples are representative of total activity  (suspended



 plus dissolved).






        The  State  of Colorado Department of Health  routinely samples  Walnut



•Creek  at Indiana  Street  (just upstream from the mouth)  on  a weekly basis.for



 gross  alpha activity  analysis. • If  the gross alpha -activity is  unusually high,



 a portion of the  sample  is  sent to  the Public Health  Service  Southwest Radio-



 logical Health Laboratory for plutonium analysis.






        In addition to the routine surveillance  programs carried out  by Dow



 Chemical Company  and  the State Health Department,  intensified monitoring was



 undertaken  following  the May 11 fire.  During May  and June 1969 Dow  Chemical



 Company reported  the  collection and analysis of 52 additional water  samples



 from the routinely sampled  reservoirs.    The Denver  Post  in  an editorial



 dated  February 12,  1970, reported that the State Health Department collected




670  air samples and 94 water samples  in the vicinity  of the plant in the

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                                  10
                               Table IT
                Gross Alpha Activities in the Environs
                       of the Rocky Flats Plant
                            3     -2
Composite Air Samples (pCi/M  x 10  )
1968





January
February
March
April
May
June
0
2
0
0
0
0
.3
.2
.5
• 5
• 3
• 7
1968 July
August
September
October
November
December
0.
0.
0.
0.
0.
0.
5
5
6
7
4
7
                                                  1969
January
February
March
April
May
June
0.5-
0.4
0.2
0.3
0.3
0.3
Grab.Water Samples (pCi/l)
Great Western Reservoir
Standley Reservoir
Baseline Reservoir
  (7 miles north of site)
Ralston Reservoir
Jan. -June
1968
2.3
1-3
1.2
4.2
July- Dec .
1968
1.4
1.5
0.9.
2.8
Jan. -June
1969
1.4
1.5
0.9
2.8
Vegetation (pCi/kg)
October 1967
.< 3 miles
3-18 .miles
October 1968
< 4 miles
4-18 miles
May 1969
< 4 miles
4-18 miles


120 (21)*
118 (40)

90 (62)
96 (44)

84 (39)
77 (20)
   Number in parentheses denotes number of analyses,
   Source: References 3> 4,  and 5.

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                                  11






time period extending from one day after the fire through October 1969•   The



State Health Department also conducted an extensive soil and bottom sediment



sampling program in February 1970-  Soil samples were collected in the area



around the plant up to a maximum radial distance of six miles.  Bottom sedi-



ment samples were collected from Walnut Creek, Woman Creek, Great Western



Reservoir, Mower Reservoir, Standley Lake, and Ralston Reservoir.  Analyses



for strontium-89 and 90 and plutonium-239 were performed by the Public Health



Service Southwest Radiological Health Laboratory (Appendix B).






       Following the May 11 fire, members of the Colorado Committee for




Environmental Information also undertook a limited program to determine



Plutonium levels in Colorado eastern slope soils and at locations in the



vicinity of the Rocky Flats Plant.  In addition to the soil samples, water



and bottom sediment samples were collected from Walnut Creek, Great Western



Reservoir, Calkins Lake, Ralston Reservoir, and three more distant lakes:



Boulder Reservoir (northeast of Boulder), Dodd's Lake (northeast of Boulder),



and Boyd Lake (Loveland, Colorado).  Based on the results obtained for the



soil samples, it was concluded "that curies to tens of curies of plutonium



from the Rocky Flats Plant have been deposited in off-site areas."  This is



in contrast to the estimate of 0.3 curie by the State of Colorado Department



of Health (Appendix B).






Water Quality Office Study



                          Sampling Procedures



Environmental samples were collected on February 25 and 26, 1970 by Water



Quality personnel with assistance from Mr. A. Hazle, Colorado Department of

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                                  12






iiealth.  The types of samples consisted of water samples, bottom sediment




c;unpleu, and filter sand and clarifier underflow camples from the Brooafield




Water Treatment Plant.






       Sampling station locations for water and bottom sediment samples are




presented in-Table III and Figure 1.  Bottom sediment samples were collected.




by scraping the bottom area below the water line with a hand trowel.  By




using this procedure,-each sediment sample was representative .of.the bottom




most readily available for physical and chemical reactions with dissolved




constituents in the water and recently deposited material.  Grab samples of




water were collected in one gallon plastic containers; 2 to 5 gallons per




sample.






       Soil samples (top 1/U" - 1/8" of soil) were collected with a hand




trowel at three locations:






1.  Ungraded area near the southeast corner of Great Western Reservoir, west:




    of the service road.




2.  Approximately 50 feet southeast of the road culvert conveying Woman Creek




    under Indiana Street.  Area has been grazed in the past.




5-  North side of Calkins Lake, about 300 feet east of the water intake sta-




    tion (grazed field).






The sampling site near. Great Western Reservoir was in the general area of the




location at which the Colorado Committee for Environmental Information




observed the maximum plutonium-239 concentration in soil.

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                                  13





       Filter sand; samples, before and after backwashing, and a sample of



the clarifier underflow were collected at the Broomfield Water Treatment



Plant.  The filter sand samples were collected by scraping the surface of



the sand bed with a hand trowel.  The sample collected at the termination



of the filter run was a mixture of "scum" and filter sand (white); the scum



representing alum floe carried over from the clarifier.  Clarifier under-



flow, a heavy slurry, was the product of alum coagulation of Great Western



Reservoir water.  Due to maintenance work on one of the two treatment cir-



cuits, the 5 MGD plant was hydraiilically overloaded at the time of sample



collection.  Raw water chemical dosages were 50 mg/1 alum, 20 mg/1 soda ash,



1.0 mg/1 activated carbon, and 6.5 ing/1 Palmer coagulant (product of the




Calgon Corporation).






                         Analytical Procedures



       The analytical procedures for determining gross alpha radioactivity,



total alpha radium, uranium, plutonium, strontium-89 and 90> and tritium



concentrations in the various environmental samples are described in detail



in Appendix C.  Pretreatment of water samples consisted of filtration through




a membrane filter of 0.^5 micron porosity.  Sediment and soil samples were



dried at 103°C and ground to pass a No. 100 mesh sieve before specific



analyses were initiated.






       Since the analytical procedure for plutonium determines "total"



plutonium, the individual results represent the contributions of plutonium-



238 and 239j not plutonium-239 alone.  By virtue of their widespread occur-




rence in:the atmosphere, both isotopes of plutonium were probably present in

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                                  Ik

                              Table  III

                           Sampling Stations
Station.
Number
  5


  6
  8
 10
	Description (Date of Collection)	

South fork of Walnut Craek at site boundary
(2/25/70)

Middle fork of Walnut Creek; 50 feet up-
stream from confluence with north fork
(2/25/70)

Main stem of Walnut Creek; 50 feet down-
stream from confluence of south fork with
middle and north forks (2/25/70)

Walnut Creek at Indiana Street (2/25/70)
(a)  East side of culvert
(b)  West side of culvert at edge of small
     pond

Great Western Reservoir at mouth of Walnut
Creek (2/25/70)

Great Western Reservoir; east end - raw
water sample collected at Broomfield Water
Treatment Plant (2/25/70).

Great Western Reservoir; south shore - com-
posite sample collected along approximately
one-half mile of shoreline extending from the
dam (2/25/70)

Great Western Reservoir; south shore - com-
posite sample collected along a 25 foot strip
in 2 to 5 inches of water (2/26/70)

Great Western Reservoir; south shore - dis-
crete sample collected above water line from
wave-deposited (or reworked) sediments
(2/26/70)

Mower Reservoir at mouth of diversion ditch;
west end (2/26/70)
     Type
                                                             Water, Bottom
                                                             Sediment

                                                             Water, Bottom
                                                             Sediment
                                                             Bottom Sediment
Water

Bottom . Sediment

Bottom Sedimen^.


Water
                                                             Bottom
Bottom Sediment
                                                             Bottom Sediment
Bottom Sediment
                              (continued)

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                                  15
                              Table  III  (continued)
                           Sampling Stations
Station
Number

  11
  12



  1.3


  14
  15


  16
	Description (Date of Collection)

Mower Reservoir; east end at dam (2/25/70)
Woman Creek at Indiana Street (2/26/70)
(a)  Small pond east of the road culvert
(b)  Channel downstream from pond

Standley Lake near mouth of Woman Creek
(2/26/70)

Standley Lake* east end (2/26/70)
(a). Center of dam near pumping station
(b)  Southwest of dam along a 25 foot
     edge of shoreline in zone of heavy
     wave action

Calkins Lake; north side (2/26/70)
Autrey Reservoir (approximately 4 miles
northeast of the plantj Boulder County)
(2/25/70)
     Type
Water, Bottom
Sediment
Water
Bottom Sediment

Bottom Sediment
                                                             Water
                                                             Bottom Sediment
Water, Bottom
Sediment

Water, Bottom
Sediment

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                                  16




the samples collected in the environs of the Rocky Flats Plant.  However,
                  i "•'

the bulk of the plutonium in each case was probably attributable to


Plutonium-239-  This conclusion is based on the plutonium monitoring of


airborne particulates and precipitation by the U. S. Public Health Service.


During 1969 the data for the Denver sampling station showed plutonium-239


concentrations to be several times higher than the corresponding plutonium-


238 concentrations.   Although the ability to differentiate between plutonium-


238 and 239 is of interest from the standpoint of analytical precision, it is


of academic importance in respect to evaluating the environmental impact of


plutonium-239 emissions from the Rocky Flats Plant.  Total plutonium is an


adequate parameter for such an evaluation since the effects of plant emis-


sions are based on increases above baseline values (plutonium attributable to


atmospheric fallout).




                                Results


       Physical and radiological data for the water samples collected during


the February 1970 study are tabulated in Tables IV and V.  The presence of


tritium (H-3), strontium-89 and 90, and radium (total alpha) in the samples


is attributable to natural sources and/or atmospheric fallout from nuclear


weapons tests; not waste releases (scheduled or accidental) from the Rocky


Flats Plant.  The average dissolved concentrations of thes'e radionuclides


were 13^0 pCi/1 of tritium, < 0.1 pCi/1 of strontium-89, 1.2 pCi/1 of


strontium-90, and < 0.1 pCi/1 of total alpha radium.



       Assuming the  accidental releases of plutonium from the Rocky Flats


Plant have not caused measurable increases in the levels of dissolved

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17
Table IV
Solids Concentrations in

Water Samples


Solids Concentration (mg/l)
Station
Walnut Creek:
South fork at site boundary (No. l)
Middle fork (No. 2)
Indiana Street (No. 4)
Great Western Reservoir (No. 6)
Mower Reservoir (No. 11)
Woman Creek (No. 12)
i
Standley Lake (No. 14)
Calkins Lake (No. 15)
Autrey Reservoir (No. 16)
Suspended
13
k
12
k
17
< 1
5
16
13'
Dissolved

150
220
250
130
110'
150
' 120
80
. 220

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                                                     Table  V
Dissolved Radioactivity in Water Samples
Dissolved Radioactivity (pCi/l)^a'
Station
Walnut Creek:
South fork at site »
boundary (No. l)
Middle fork (No. 2)
Indiana Street (No. 4)
Great Western Reservoir
(No. 6)
Mower Reservoir (No. 11)
Woman Creek (No. 12)
Standley Lake (No. 14)
Calkins Lake (No. 1"5)
Autrey Reservoir (No. 16)
Gross
Alpha
N.D.
0.9
0.6
0.8
0.8
0.9
0.5
0.5
0.8
Tritium

N.D.
N.D.
N.D.
1340
1050
N.D.
1390.
1550
1390
Sr-89

0
0.1
0.1
0
0
0.5
0
0
0
Total Alpha
Sr-90 Radium

0.6 0.1
0.7 < o.i
0.6 < 0.1
1.4 0.1
1.8 O'.l
0.4 < 0.1
0.6 < 0.1
2.2 0.2
2.1 < 0.1
Uranium

7-9
2.7
4.8
2.6
1.1
2.2
2.4
2.7
0.5
Plutonium-239

0.04
0.02
0.05
0.03
< 0.02,
< 0.02
< 0.02
0.03
< 0.02
 (a)  Uranium in  ng/1




.N.D. -  Not determined

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                                  19




Plutonium in Autrey Reservoir,  Calkins Lake, and Standley Lake, the appar-



ent  "baseline" concentration Tor dissolved plutonium from the uncontrolla-



ble  source, atmospheric fallout, was ^ 0.03 pCi/1 at the tinie of sampling.



As shown in Table V and Figure 2, only the samples from Walnut Creek



(Stations Nos. 1 alid ^-) exhibited slightly higher concentrations - 0.04- and



0.05 pCi/1, respectively.  Similarly, these same two stations on Walnut



Creek were the .only locations at which the dissolved uranium concentration



exceeded the average area background concentration of approximately 2 ng/1.



The sample of raw water from the east end of Great Western Reservoir (Sta-



tion No. 6) did not indicate any increased' level of uranium and/or plutonium



contamination as the result of liquid waste discharges to Walnut Creek.  .  .





       For comparative purposes, the plutonium-239 results for water samples


          • •          •                                           4
reported by the Colorado Committee for Environmental Information   are sum-*



marized below.  It is assumed that the samples were.collected during August



1969.                                          •   .           .'

         . !        .                                   " _         -   •

                                                 Plutonium-239

                  Location	                  (pCi/l)      .



          Walnut Creek - Roadside

             pond at Indiana Street      .        .0.19



          Great Western Reservoir         .            0.10



.     ,     Ralston Reservoir                           0.01



       .   Calkins Lake .   .            .      .          0.01





These data agree favorably with the corresponding results from the February



study.  The substantially higher concentration in Walnut Creek is not



unusual or unexpected considering probable differences in flow conditions

-------
                                  20


and the batch nature of liquid waste discharges.  What does appear to be a

significant difference is the concentration reported for Great Western

Reservoir which would be indicative of measurable contamination in the

reservoir as the result of plant wastes.  However, the discussion of the

results in their report indicates that this station was actually located in

or near the mouth of Walnut Creek:
        11  ... The highest Pu    concentrations observed are those for
       Great Western Reservoir and the small roadside pond, both on
       Walnut Creek ..."

Thus, this particular sample was apparently not representative of general

water quality in Great Western Reservoir.


       The radioactivity data for bottom sediment samples are presented in

Table VI.  Average concentrations of strontium-89, strontium- 90, and total

alpha radium in all sediment samples were < 0.5, 0.1, and U.9 pCi per gram

dry weight, respectively.  For all stations, except those on Walnut Creek,

the uranium concentrations ranged from 0.4 to 2.8 ng per gram dry weight;

averaging 1.0 ng/gram.  Considering these values and the result for the

middle fork sample, no significant accumulation attributable to the discharge

of uranium-bearing liquid wastes was observed in the Walnut Creek samples.

Excluding the station on the middle fork, the average uranium concentration

for Walnut Creek sediments was 1.5 i^/gram.  The average concentration for

plutonium-239 at baseline locations (Autrey Reservoir, Standley Lake, and

Calkins Lake) was 0.05 pCi per gram dry weight.  This b-celine concentration

is comparable to the concentrations reported by the Colorado Committee for

Environmental Information   and the State of Colorado (Appendix B) for

-------
          I
          N
                                                      AUTREY RESERVOIR
                                               <0.02
                                  0.05
       U.S. ATOMIC
   ENERGY COMMISSION   I
   ROCKY FLATS PLANT   I
                       J
                                              	e 0.03

                                                GREAT WESTERN RESERVOIR
                                          MOWER RESERVOIR
I	
                                                       STANDLEY LAKE  &<0.02
              FIGURE 2
    DISSOLVED PLUTONIUM IN WATER
                pCi/l
                                        4000
                                          i
8000 FT.
                                                                                CALKINS
                                                                                  LAKE
                          POMONA LAKE

-------
                                  21


sediments from Standley Lake, Calkins Lake, and Ralston Reservoir - average

of 0.07 pCi/gram dry weight with a range of 0.01 to 0.18.


       Accumulation of plutonium from liquid waste discharges was observed

in sediment collected from the middle fork and main stem of Walnut Creek.

As shown in Table VI and Figure 3, plutonium concentrations in Walnut Creek

ranged from a maximum 3«5 pCi/gram just below the plant boundary to less

than 2 pCi/gram in the lower reach of the main stem (Indiana Street to the

mouth).  In comparison to the observed level of contamination (k to 7X

baseline), similar results obtained by the State of Colorado indicated a

substantially higher level of contamination.  These data corresponding to

the collection date of February 18, 1970* were as follows;


                                                 Plutonium-239
          	Location 	         (pCi/gram dry weight)

          Upper south Walnut Creek                     21

          Walnut. Creek                        .         49

          Pond; Walnut Creek at
             Indiana Street                            13


Since flushing of the creek by heavy runoff did not occur in the week

between the collection dates, the only reasonable explanations for the

apparently different sets of findings are differences in the hydrological

characteristics of the sampling locations (pool versus riffle or a combina-

tion thereof) and sampling techniques (thickness of the scraped layer,

heterogeneity of sample- composition, etc).  For example, considerable varia-

tion would be expected for samples collected from the pond at Indiana Street

-------
Table VI
       Station	

Walnut Creek:
   South fork at site
      boundary (No. l)

   Middle fork (No. 2)

   Main stem, below confluence
      with middle fork (No. 3)  17
   Indiana Street (No. 4)

   At the mouth (No. 5)


Great Western Reservoir:
   South shore near dam
      (composite)(No. 7)

   South shore (composite)
      (No. 8)

   South shore (discrete
      sample)(No. 9)

Mower Reservoir:
   West end (No. 10)
   East end (No. 11)

Woman Creek (No. 12)
lioacti

Gross
Alpha
18
10
17
&
13
7
12
12
11
13
9

vity in Bottom
Radioactivity
Sediment Samples

Concentration (pCi/gram dry
Total Alpha
.Strontium-90 Radium
0.1
0.1
0
0.1
0.3
0.2
0
0.2
o
0.1
0

3.4
-5A
2.8
4.1
6.3
5.4
6.3
6.6
4.3
3-3
4,8
(continued)
weight)^ '
Uranium Plutonium-239
1.1
2.3
1.0
2.1
1.9
1-3
0.4
2.8
0.5
0.4
1.5

3.51
0.50
3.41
0.92
1.75
0.10
0.11
0.13
0.10
. 0.09
0.23

                                                           ro
                                                           ro

-------
        N
                                                    AUTREY RESERVOIR
                                              0.03
                     10.50
                                   0.92
    U.S. ATOMIC
ENERGY COMMISSION   I
ROCKY FLATS PLANT   I
                                              GREAT WESTERN RESERVOIR
                                         0.13
                                              0.10
                                        MOWER RESERVOIR
                                          09
|	._	
       FIGURE 3
PLUTONIUM IN SEDIMENTS
         pCi/g
                               0
                               i
                                          4000
                                           i
8000 FT.
                                                                               CALKINS
                                                                                 LAKE
    0.06
    1—'—.

POMONA LAKE

-------
                                            Table VI  (continued)
                            Radioactivity In Bottom Sediment Samples
       Station
Standley Lake:
   Near mouth of Woman
      Creek (No. 13)
   East end (No.
Calkins Lake (No. 15)

Autrey Reservoir (No.  16)
Gross
Alpha
 10
  8

  7

  8
                                      Radioactivity Concentration (pCi/gram dry weight)^  '
Strontium-90



    0.2

    0

    0

    0.2
Total Alpha
  Radium
   12.5

    0.7
    3-2
Uranium    Plutonium-239
  0.6

  0.6

  0.7

  0.7
0.05
0.04

0.06

0.03
                                                                                                     ro
(a)  Uranium in ng/gram
Strontium-89 less than 0.5 pCi/gram in each case.

-------
                                  2k






depending on whether the samples are collected near the head end of the




pond, the center, or just below the waterline along the periphery of the



pond.  The contamination observed in sediment from the middle fork of



Walnut Creek and Woman Creek (at Indiana Street) was probably caused by



wind transport and/or surface runoff of plutonium-contaminated soil.  The



State of Colorado also observed contamination in Woman Creek - 1.0 pCi/gram




for a sample collected on February 18, 1970.






       Although certainly not conclusive, the sediment samples from Mower



Reservoir and Great Western Reservoir indicated measurable, albeit slight,



accumulation of plutonium as the result of accidental airborne releases from




the plant.  The discharge of plutonium-bearing liquid wastes was not con-



sidered a causative source since the samples from Great Western Reservoir



were collected at locations wherein the ultimate deposition of sediment from



Walnut Creek would be most unlikely.  Actually, these sediment samples should



be considered representative only of shallow, shoreline conditions and not



the general bottom condition in the respective reservoirs.  Assuming the bot-



tom materials in these shallow areas were similar to nearby topsoils as




regards plutonium content, the suggested possibility of accumulation above



baseline values in the shoreline sediments is not completely implausible.



Both reservoirs are within sectors characterized by "elevated" levels of



plutonium in soil (Appendix B).






       The clarifier underflow sample from the Broomfir-ld Water Treatment



Plant showed that the treatment process produced a finished water of lower



uranium and plutonium concentrations than the raw water.  On a dry weight

-------
                                  .     .
basiu, the alum sludge contained the maximum concentration of uranium among


all the samples analyzed;  the plutonium concentration was of the same mag-


nitude as that, observed for Walnut Creek sediment samples (Table VII).


Carryover of the floe to the sand filter was shown by the uranium and


plutonium content of the filter sand samples collected before and after


backwashing.



       Plutonium-levels observed in the three soil samples are summarized


in Table VIII, and are consistent with similar findings of the State of


Colorado and the Colorado Committee for Environmental Information.



       Spearman rank-order correlations were performed between the gross


alpha and uranium, total alpha radium, and plutonium results, respectively,


for sediment and soil samples.  Interestingly,  there was no correlation


"between gross alpha and uranium or gross alpha and total radium, but a


significant correlation between gross alpha and plutonium results at the


I/a confidence level. . Despite this relationship, gross alpha measurements

                                                                       " ^
alone are not adequate for assessing the environmental impact of plutonivijj}


releases (accidental or scheduled) from the plant.  Although the gross alpha


analysis is responsive to substantial increases in plutonium levels, it


lacks sufficient precision for detecting the small subtle changes which


have occurred in the environs of the Rocky Flats Plant.

-------
                                            Table  VII
                             Broomfield Water Treatment Plant Samples
                                  Radioactivity Concentration (pCi/gram dry weight)
                                                                                    (a)
Total Alpha
Sample Description Gross Alpha Strontium-90 Radium Uranium
Clarif ier underflow
(alum sludge) 34 1.2 3.1 57.5
Filter sand:
Before backwash 12 0.3 3.0 20
After backwash 4 0: 0.3 0.2

Plutonium-239

1.42

0.16
0.04
                                                                                                       ro
                                                                                                       CTN
(a)   Uranium in jig/gram

-------
                                                   Table VIII
                                         Radioactivity in Soil Samples
           Location
Ungrazed area near the south-
   east corner of Great
   Western Reservoir. (NE 1/4
   Sec. 1, T.2S.,R.69W.)

North side of Calkins Lake;
   ungrazed field east of
   water intake station.
   (NW 1/4 Sec. 26, T.2S.,
   R.69W)

Grazed area just to the south-
   east of the road culvert
   conveying Woman Creek under
   Indiana Street. (NW 1/4
   Sec. 18, 'T.2S., P.69W)
                                             Radioactivity Concentration (pCi/gram dry weight)
                                                                                              (a)
                                          Total Alpha
Gross Alpha  Strontium-89   Strontium-90     Radium
                                       Uranium   Plutonium-239
     12
     16
< 0.5
                 < 0.5
< 0.5
0.6
1-7
               0.4
            4.0
2.8
1.6
1.0
0.42
                                                                                   ro
0.07
2.42
(a)  Uranium in fig/gram

-------
 Discussion


        Surface  contamination  of land  surfaces in the vicinity  of  the  Rocky


 Flats Plant  has occurred  as the result  of uncontrolled  releases of  pluto-


 nium. The  special  soil  sampling program conducted by the  State of Colorado


 in February  1970 showed plutonium concentrations in excess  of  that  attrib-


 utable to  global fallout  at radial distances up to three  miles from the


 plant boundary. The  two  sectors (refer to Appendix B)  immediately  adjacent


 to the plant showed the Tna-v-taym topsoil concentrations  of plutonium-239;


 2.5 and 11 pCi  per gram dry weight.   It was the State's conclusion  that the


 primary source  of  contamination was the "incident" involving the  leakage of


 oil and not  the May 11, 1969,  fire.   In contrast, the report.of the Colorado


 Committee  for Environmental Information strongly suggested  the May  11 fire


 as the primary  causative  factor.   As  far as the publiu  health  implications


 Of the land  contamination are concerned, the source, whether it be  the


 incident involving the  fire or the oil  leakage, is not  really  revelarit.




        It  is extremely  difficult to attempt.to  relate plutonium concentra-


 tions in unconsolidated topsoil to possible or  potential  levels of  human


 exposure.  Deposited  in-place,  there  is no significant  health  risk. External


 exposure will not  occur because of the  very limited range of the  emitted


 alpha radiation.   Similarly,  transfer through the food  chain (for example,


 soil to vegetation to wild game or grazing stock) will  be of no consequence


 since plutonium is absorbed by plants growing on contaminated  soil  to only

                        Y
 an infinitesimal degree.    However,  resuspension and wind  transport  of


 contaminated particulates - apparently  a likely condition for  the Rocky Flats


area-may lead  to  inhalation  and  resultant radiation dose.  For discussion of

-------
                               •   29

this latter pathway and the potential health risk it represents, the int-

erested reader is referred to the State of Colorado's analysis (Appendix B)

and the report of the Colorado Committee for Environmental Information.

       The discharge of liquid radioactive wastes was observed to have only
a minor effect on dissolved radioactivity concentrations in Walnut Creek, at

least during the two-day sampling period.  The dissolved concentrations of

uranium and plutonium were just slightly in excess of baseline values and,.

in each case, several orders of magnitude less than the corresponding

effluent concentration specified in AEC regulation 10CFR20, and the limiting
concentration in water for the general public, as recommended by the National

Committee on Radiation Protection and the International Commission on Radio-

logical Protection (Table IX).  Unfortunately, the degree to which the

specific grab sample results are representative of average or long-term con-

ditions can only be determined by additional monitoring.  The effluent to the

south fork of Walnut Creek has been continuously sampled by plant personnel

and the State of Colorado has been monitoring WalnutCreek at Indiana Street,

The analysis of these samples usually involves only total gross alpha deter-r

minations, the results, of which are not directly comparable with dissolved

radioactivity data.  However, the effluent concentration of total gross alpha

activity stated to,be typical, 15 pCi/1, indicates that specific findings for

the levels of dissolved uranium and plutonium may actually be representative

of average water quality conditions in the creek.
                                         i
       The most demonstrable effect of liquid radioactive waste discharges
was the accumulation of plutonium in bottom sediment throughout the entire

-------
                                             Table IX
                       Limiting Concentrations for Plutonium-239 and Uranium.
         Agency
Atomic Energy Commission
Badionuclide

Plutonium-239

Uranium-238
                                                       Dissolved
                                                     Concentration
                                                       •  Limit

                                                      5000 pCi/1

                                                       120 mg/1
      Applicability

 Effluent at point of
 entry into the
 unrestricted area.
National Committee on
   Radiation Protection
Plutonium-239
                                                     1700 pCi/1
                                                               (a)
 Exposure of the general
 public
International Commission
   on Radiological Protec-
   tion.
Uranium-238
                                                   ko mg/1

                                                  600 ug/1
 Exposure of the general
-public
(a)  l/30th of the maximum permissible concentration for continuous occupational exposure (168-hour
                                                                                              week).

-------
                                  31





length of Walnut Creek.  Representing accumulation and deposition over an



undetermined period of time, the February 1970 sediment samples contained



Plutonium in concentrations as high as 3-5 pCi/gram (State of Colorado



data showed a maximum of about 20 pCi/gram).  Such accumulation occurs by



two processes:  1) deposition of plutonium associated with suspended mate-



rial in the effluent, and 2) transfer of plutonium from the dissolved



(ionic) state by chemical precipitation and/or adsorption.  From the stand-



point of environmental significance as regards human exposure> plutonium



deposited in Walnut Creek is of no consequence.  However, these contaminated




sediments are periodically flushed out of the creek and deposited in Great



Western Reservoir wherein there exists availability for incorporation and



accumulation in the aquatic web*  The limited available information on the



movement of plutonium in the environment indicates that biological accumula-



tion as .well e.s dissolution of plutonium from the sediment will be negligi-



ble.  Nonetheless, the previously mentioned study of September 1970 was con-



ducted to ensure that these predictions are indeed valid.






       In contrast to the situation in the south fork and main stem of



Walnut Creek, the sources of elevated plutonium concentrations in samples



from the middle fork of Walnut Creek, Woman Creek, and shallow shoreline



areas of Great Western Reservoir and Mower Reservoir were considered to be



air transport and surface runoff of plutdnium-contaminated soil.  As noted



in the preceding paragraph; the plutonium deposited in these areas is prob-



ably; biologically and chemically inert:

-------
                                  32                              '  '






       Increased levels of dissolved radioactivity attributable to plant




releases were not observed in any of the lakes and reservoirs sampled.




This finding is generally supported by the long-term monitoring data com-



piled by plant personnel for several reservoirs in the plant environs,



including Great Western Reservoir and Standley Lake.  However, since the



plant monitoring program is limited to total gross alpha determinations,  •



detection of small increases in plutonium concentrations, such as those



observed in Walnut Creek, would not be expected.  It is also interesting




to note that the concentrations of dissolved uranium in the grab water



samples from Great Western Reservoir and Standley Lake almost totally



account for the corresponding reported levels of total gross alpha concen-



trations.  The radiation dose associated with the utilization of Great



Western Reservoir, Standley Lake, and Calkins Lake as sources of public



water supply is negligible.  Without taking credit for possible concentra-



tion reductions achieved by water treatment, the dose received by members



of each population group served is less than one one-hundred-thousandth



(10~5) of the dose limit for individuals.






       The apparent effectiveness of the Broomfield water treatment process



for reducing uranium and plutonium concentrations - raw versus finished



water - was indicated by the radioactivity results for the sample of settled



alum sludge.  On a dry weight basis, the plutonium and uranium concentra-



tions in the sludge were comparable to the plutonium concentrations and



about 40X the uranium concentrations in Walnut Creek sediment.  Disposal of



the sludge is to a small retention pond adjacent to the water treatment




plant.

-------
3-     At least annually, preferably semi-annually/ levels of plutonium



       in the various trophic levels of the aquatic populations inhabit-




       ing Great Western Reservoir and Standley Lake should be determined.






k.     Semi-annual monitoring reports should• "be expanded to include data



       on effluent flow and radioactivity concentrations.in the effluent



       to the south fork of Walnut Creek.  Sufficient data should be pre- .



       sented to permit the calculation of at least the monthly amounts



       (curies) of plutonium and  uranium (suspended and dissolved) dis-



       charged to the creek.






       Any recurrence of "incidents" resulting in off-site contamination



cannot be tolerated; irrespective of the associated level of off-site con-




tamination - negligible or of potential public health significance.  What-



ever preventive measures and/or facilities are considered necessary for the



absolute prevention of incidents resulting in the venting of radioactive



materials to the atmosphere must be implemented and/or installed.  Remote-



ness of location is not a safety factor in this particular case, and tHl-S



must be reflected accordingly in the operational aspects and safety program



of the plant.

-------
                                  33
Conclusions
       Monitoring data do not indicate any public health hazard associated



with the routine discharge of liquid radioactive wastes to Walnut Creek.



There has been no measurable degradation of plant origin in the radiologi-



cal water quality of Great Western Reservoir, the source of public supply



for the City of Brootafield.  This reflects the general adequacy of the



liquid waste management program carried on at the Rocky Flats Plant.  In



-his respect, additional abatement requirements are not indicated at this



time.






Recommendations           .




       In order to obtain a more comprehensive documentation of the radio-



activity discharged to the environment via the liquid radioactive waste




treatment and disposal system and the ultimate distribution thereafter,



the Water Quality Office has the following recommendations:






1..    Routine monitoring of radioactivity levels in water in the effluent



       to Walnut Creek, Walnut Creek (at.Indiana Street culvert) and Great



       Western Reservoir should include determinations of suspended and



       dissolved radioactivity;  not total radioactivity in the unfiltered



       sample.






2.     In addition to gross alpha activity determinations, specific analyses



       should be conducted for plutonium-239 and uranium.

-------
Appendix A

-------

-------
Appendix B

-------
                                       37
      COLORADO       '. ;:r-lE?'T Or  HEALTH

               4P/0 EAST 11TH AVENUE - DENVER, COLORADO 80220 - PHONE 388-6111
                                                   R. L. CLEERE, M.D.. M.P.H., DIRECTOR

                                                   June 9, 1970
Enclosed are copies of the latest surveillance' information on the Rocky Flats
Plant.  You will note the soil sample results clearly indicate the distribution
of the 239py contamination.

Before briefly describing the soil analysis results, it might be well to first
explain the sampling technique used.

The U.S.P.H.S. obligated themselves to analyze 25 total samples for 2^9pu an<}
'"Sr content.   This was because the plutonium analysis, in particular, is ex-
tremely time consuming and they, of course, have other commitments for other
surveillance activities.  To take full advantage of this limited number of analy-
ses, it was decided that a composite sampling program was indicated.  As you can
see by the map attached to the soil analysis results> the area around the Rocky
Flats Plant was divided into 13 sectors.  These sectors were located at 1, 3 and
6 mile distances from the plant boundary.  Twenty-five soil samples were collected
in each sector with 207, or 5 separate samples collected additionally in each sector
and retained for future reference.  Each location sampled is approximated on the
map.  The number of composite soil samples in the designated area totaled 325.
Composite sediment samples of significant water bodies totaled 190.  The soil sam-
ples collected were of the top 1/8" of undisturbed soil which would be indicative
of the most severe health hazard in regard to re-suspension from the soil to the
air.

It is interesting to note the similarity of results of- the 75 background samples
collected in Limon, Loveland and Penrose areas using the same composite sampling
technique as described above.   Although we plan to expand the number of background
sampling areas, we anticipate that the present samples accurately describe the
239pu "background" levels on the Eastern Slope.  These levels are due almost entirely
from fallout from past atmospheric nuclear testing.

Also worthy of note, are the results of the "^Sr analyses and the  •''Pu/'^Sr ratios
for sector soil samples, "background" soil samples and sediments.  These results
would indicate that the    Pu results alone are the best indicator of the effect
that the Rocky Flats Plant has had on the environment.

-------
 June  9,  1970
 Page  2


 It:  i:; our  conclusion  that no public health hazard now exists from past releases
 from  the Rocky Flats  Plant.  It would be impossible, however,  to estimate any
 luixarcl which existed  in  the past.  The highest concentrations  were  found adjacent
 t:o  the plant at  the eastern boundary.  This area is directly downwind from  the
 area  that  the leakage of plutonium-contaminated oil and subsequent  soil contami-
 nation occurred  sometime during the period of 1955 through 1967.    The main oil
 spill area was covered with asphalt in September, 1969 and an  apron of 3" of base
 course material  was completed around this area in March, 1970.  The plutonium
 levels in  the soils in this area were high and the material was carried downwind.
             9 TO
 The elevated ^  -Pn levels in Sectors 1, 2, 6 and 7 are primarily the result of  this
."incident."                                         ,

 Sector 2, which  has the highest concentration' of 239pu? can best be described as a
 non-populated area, access to which is not controlled.  In a paper  by R. L. Kathren
 (1968), which was an extensive review of work done on plutonium contamination,
 "interim acceptable surface contamination levels for environmental  PuC^" are pro-
 posed.  Based on dose to pulmonary lymph nodes, the following  would be acceptable
 levels for occupancy by the general public:

                              Urban areas        10 dpm/cm^
                              Rural areas       100 dpm/cm^

 ICRP Publication 14 (1969) states that the dose limit for plutonium on the  basis of
 risk to lymphoid tissue is not warranted.  Adjustment of the above  proposed accept-
 able levels would be. upward by a factor of 2 or more.  Based on the conservative
 numerical terms used by Kathren, the level identified in Sector 2 (8 dpm/cm^) is
 safe  (acceptable) by at least a factor of 25:  If the entire 13-sector area
 (0.3 dpm/cm^) is used, the factor would range from 70 to 700 depending on whether
 the entire area  would be considered as urban or rural,, respectively.  Less conser-
 vative limits would, of course, provide a greater factor, and  several of these were
 reviewed;                                        •
                                                   O O Q
 Extrapolation of the data indicates that the total •"'Pu soil  contamination of the
 environment around the Rocky Flats Plant attributable to the plant  approximates
 0.3 Curie  (4.9 grams ^^°Pu) at the present time, 57% of which  is located in Sector 2.

 Because hazard analysis based on soil data utilizes arbitrary  re-suspension and "air
 concentration half-life" factors, the only proper method to thoroughly evaluate the
 situation is by air surveillance.

 The Department's plans are to continue, and in some cases increase, air surveillance
 activities downwind from both the contaminated area and the plant in general, and to
work with Rocky Flats personnel in an effort to more fully identify and control any
 potential contaminant releases from the plant. . Samples from Sector 2 will be col-
 lected and analyzed to determine the long-term characteristics of    Pu in soils,

-------
                                       39
June 9, 1970
Page 3
and of course as previously mentioned, an expanded effort will be made to es-
tablish an existing 239pu "background" for Colorado.   With the provision of
additional funds, a higher percentage of samples (air, water and soils) will
be analyzed for 239pU) thereby giving the Department  an independent capability
for hazard analysis, and definition of plant releases.

If you have any questions regarding this matter, please let us know.

                                        Sincerely,
                                        P.  W.  Jacoe,  Director
                                        Division of Air,  Occupational,
                                        and Radiation Hygiene
PWJ/md
Enclosures

-------

-------
 SOILS:
   Backgrounds
   Sample Date
    2/18/70
    2/18/70
    2/18/70
                        U.S.P.H.S.    -   SWRHL Analysis
                        Soil & Sediment Sampling Results
                 Location
              Limon, Colorado
              Loveland, Colorado
              Penrose, Colorado
Samples
2/18/70 ,
2/19/70
2/18/70
2/18/70
2/18/70
2/18/70
2/19/70
2/18/70
2/18/70
2/17/70
2/18/70
2/17/70
2/19/70

Area 1
Area 2
Area 3
Area 4
Area 5
Area 6
Area 7
Area 8
Area 9
Area 10
Area 11
Area 12
Area 13
upui/
23V
0.13
0.11
0.11
& ui y sui
90,
2.9
1.8
1.6
1 Ratio
Pu/Sr
0.045
0.061
0.069
5.55
24.4
0.29
0.31
0,24
1.00
1.02
"0.04
0.02
0.38
0.07
. 0.02
0.04
2.4
2.4
3.3
3.6
15.8
1.6
1.3
1.1
<0.4

-------
                    OOQ
              Total ^-*?Pu Activity By Sector
 Pu
         239
Pu            Area
d pin/ g
Sector dry 'no:
I
2
3
4
5
6
7
8
9
10
11
12 <
13
Totals
Bkg
Net (Dow
5.55
24.4
0.29
0.31
0.24
1.00
1.02
0.04
0.02
0.38
0.07
: 0.02
0.04
-
0.12
:Soil
2 2
i. 1 dpm/cm mi
1
7
0
0
0
0
0
0
0
0
0

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                           Analytical Methods



        The analytical procedures used in this study are taken from the

 published literature with adaptation or modifications made in the pre-

 treatment of the sample to fit the published analytical procedure.  The

 limit of detection is that limit which is defined in the National Bureau

 of Standards.  Handbook 86, page 26.


        Analyses for water were done on the dissolved portion only; that

 is, the portion which passes through a 0.45 jo. porosity millipore filter.

 Soils and sediment samples were dried at 105° - 110°C, ground and sieved

. to 100 mesh.


 Gross Alpha Analyses

        One hundred milligrams of dissolved solids or sediment were trans-

 ferred to a stainless steel planchet,  distributed evenly,  fixed by a dilute

 lucite solution, and alpha counted in an internal proportional ppunteifi'

.The background count rate was nominally 0.1 cpm and the detection efficiency,

 based on a radium-226 standard, was nominally 30%.  The limit of detection

 for water samples varied with dissolved solids concentration, ranging from

 1-4 pCi/1, and for sediment and soil samples, 1.4 pCi/g.


 Total Alpha Radium
                                              Q
        The procedure used was that pf Goldin,   *oth modifications ma4e fpr

 the pretreatment of sediment and soil samples.  This modification consisted

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                                   kk




  •                                                           9
 ol' fusion of the sample using the flux described by Rushing.    The limit



 oi' detection, based on a radium-226 calibration standard, is 0.1 pCi/g-



 and 0.1 pCi/1, respectively, for sediment and water samples.





 Uranium                                                              .



        The procedure used for vater analysis was essentially that of



 Edwards.     Soils and sediments were acid leached and the uranium 'extracted



 into ethyl acetate from an acidified magnesium nitrate solution.  Uranium  is



 determined fluorometrically    using a standard addition technique rather



 than by alpha spectroscopy.  Limits of detection (10$ full-scale, using 0.05



 ug standard) are 0.3 M-g/1 and 0.3 ug/g for water and sediment, respectively.
 Strontium-90


                                                      . iy             13

        The procedure used was taken from Krieger et al    and Velten.     Pre.-




 treatment of sediment and soil samples consisted of acid 3.eaching with




 6w HC1, using a Soxhlet extractor.  Limits of detection are 0.1 pCi/g and




 0.3 pCi/l..for sediment and water, respectively.






 Plutonium
        Pretreatment of sediment and soil samples consisted of acid leaching




. with 6N IIC1,    using a Soxhlet extractor, and ultimate conversion to the




 nitrates by repetitive evaporation with nitric acid.  Water samples are




 evaporated to dryness and treated with .nitric acid.  Plutonium is oxidized


                                                                          15
 and extracted .from k-N nitric acid into 0.1 m  tri-n-octyl-ohosphine oxide.




 Plutonium is reduced and back extracted and counted in an internal propor-




 tional counter.  Limits of detection are 0.02 pCi/g and 0.02 pCi/1 for sedi-




ment  and water, res-pectively.

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Appendix C

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                             BibliQgraphjr
1.  Colorado Committee for Environmental Information, "Report on the Dow
    Rocky Flats Fire : Implications of Plutonium Releases to the Public
    Health and Safety."  Boulder, Colorado (January 13, 1970)
2.  Information provided by Mr. E. S. Ryan, ''Waste Disposal Specialist, Dow
    Chemical Company.


3i  Dow Chemical Company, "Rocky Flats Plant, January-June 1968," in  "Radio-
    logical Health Data and Reports, "  9/H, pp. 702-703 (November 1968).


4.  Dow Chemical Company, "Rocky Flats, July-December 1968," in "Radiologi-
    cal Health Data and Reports," 10, 6, pp. 277-278 (June 1969).


5-  Dow Chemical Company, "Rocky Flats Plant, January-June 1969," in  "Radio-
    logical Health Data .and Reports," 11, 2, pp. 100-103 (February 1970)


6.  Private communication from Mr. J. Eckley - plant operator; Broomfield
    Water Treatment Plant.
7.  Olafson, J. H.'/ and Larson, K. H., "Plutonium, Its Biology and Environ-
    mental Persistence," in "Radioecology," edited by V. Schultz and A. W.
    Klement, Jr.> pp. 633-639, Reinhold Publishing Corporation, New.York,
    New York, and the American Institute of. Biological Sciences,Washington,
    DC. (1963)                 .


8.  Goldin, A. S., "Determination of Dissolved Radium," Anal. Chem., 33,
    406 (March 196!)
9.  Rushing, D. E., et al, "The Analysis of Effluents and Environmental
    Samples from Uranium Mills and of Biological Samples from Radium,
    Polonium, and Uranium."  Radiological Health and Safety in Mining and
    Milling of Nuclear Materials, Vol. II, 187 (1964), International Atomic
    Energy Agency, Vienna, Austria.


                                  46

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Tritium


                                                  12
       This procedure is taken from Krieger et al,     with the exception



tnat the volume ratio of scintillator to sample is increased to 5tl«



Limit  of detection is kOO pCi/1.

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10.  Edwards, K. E., "Isotopic Analysis of'Uranium in Natural Waters by
     Alpha.Spectroscopy, "  U. S. Geological Survey Water-Supply Riper
     1696-F (1968)


11.  Barker, F. B., et al.,  '^Determination of Uranium in Natural Waters,"
     U. S. Geological Survey Water-Supply Paper 1696-C (1965)


12.  Krieger, H. L., et al., Eds., "Radionuclide Analysis of Environmental
     Samples, A Laboratory Manual of Methodology,  R59-6 (Rev. 1966),"
     U. S. Public Health Service,. DHEW


13..  Velten, R. J., ."Resolution of   Brand   Sr in Environmental Media by
     an Instrumental Technique." Nuclear Instruments and Methods, k2,
     169-172 (1966)


1^.  deBortoli, M. C.,  "Radiochemical Determination of Plutonium in Soil
     and Other Environmental Samples."  Anal. Chem. 39, 375-377 (March 1967)


15.  White, J. C., Ross, W. J., "Separations by Solvent Extraction with
     Tri-n-octylphosphine Oxide,"  NAS-NS 3102, National Academy of Science,
     Natibnal Research Council  (1961)

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