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
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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
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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
-------
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
-------
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.
-------
Appendix C
-------
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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