SA/TIB-29
PLUTONIUM LEVELS IN THE SEDIMENT
OF AREA IMPOUNDMENTS
ENVIRONS OF THE ROCKY FLATS PLUTONIUM PLANT
COLORADO
TECHNICAL INVESTIGATIONS BRANCH
SURVEILLANCE AND ANALYSIS DIVISION
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
February, 1975
-------
£PA
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
INTRODUCTION
SAMPLE COLLECTION AND ANALYSIS PROCEDURES
RESULTS
DISCUSSION
SUMMARY
REFERENCES
APPENDICES
APPENIX A
APENDIX B
Core Log
EPA Region VIII LIBRARY.
Denver, Colorado
-------
LIST OF TABLES
No. Title Page
I SEDIMENT SAMPLING STATIONS/CHERRY CREEK 5
RESERVOIR, MARSTON LAKE, AND RALSTON RESERVOIR
II PLUTONIUM CONCENTRATIONS IN SEDIMENT SAMPLES/ 8
RESERVOIRS IN THE DENVER METROPOLITAN AREA
III PLUTONIUM CONCENTRATIONS IN SEDIMENT SAMPLES/ 9
STANDLEY LAKE
IV PLUTONIUM CONCENTRATIONS IN SEDIMENT SAMPLES/ 11
GREAT WESTERN RESERVOIR
A-1 CESIUM-137, STRONIUM-89 AND 90, PLUTONIUM-238 A-2
BERYLLIUM, AND POTASSIUM IN DREDGE SAMPLES/GREAT
WESTERN RESERVOIR AND STANDLEY LAKE .
A-II PLUTONIUM-238 AND BERYLLIUM IN CORE SAMPLES/ A-3
GREAT WESTERN RESERVOIR AND STANDLEY LAKE
B-I SEDIMENT SAMPLE COMPOSITION/CHERRY CREEK RESERVOIR, B-21
MARSTON LAKE, AND RALSTON RESERVOIR
- ii -
-------
LIST OF FIGURES
No. Title Page
I BOTTOM SEDIMENT SAMPLING STATIONS/GREAT 3
WESTERN RESERVOIR/OCTOBER 18, 1973
II BOTTOM SEDIMENT SAMPLING STATIONS/STANDLEY 4
LAKE/October 25, 1973
III PLUTONIUM-239 (pCi/gram) IN DREDGE SAMPLES/ 13
GREAT WESTERN RESERVOIR/October 18, 1973
IV PLUTONIUM-239 (pCi/gram) IN DREDGE SAMPLES/ 14
STANDLEY LAKE/October 25, 1973
- iii -
-------
INTRODUCTION
In September, 1973, the U.S. Environmental Protection Agency responded to a
request from the Colorado Department of Health to assist in the investigation
to verify the suspected release(s) of tritium in liquid wastes from the Rocky
Flats Plant of the U.S. Atomic Energy Commission. Although focused on the
determination of tritium concentrations in area surface waters and the identi-
fication of the source(s) of 'such contamination, the overall scope of field
investigation was expanded to include the monitoring of plutonium contamina-
tion of bottom sediment in Great Western Reservoir and Standiey Lake (conducted
during October, 1973). Both of these reservoirs lying short distances to the
east of the plant receive drainage from the site. Through 1973, Great Western
Reservoir received treated liquid wastes (plutonium-bearing) from the Rocky
Flats Plant via the tributary stream, Walnut Creek.
Extensive sampling of bottom sediment in Great Western Reservoir was conducted
previously by the Environmental Protection Agency during September, 1970. This
sampling program also involved sediment sampling of an exploratory nature in
Standley Lake. As reported U), the 1970 findings indicated the following:
(1) Almost the entire bed of Great Western Reservoir was covered with sediment
containing plutonium in excess of the estimated baseline concentration,
< 0.10 pCi/gram, attributable to worldwide fallout from nuclear weapons
testing.
(2) The possible existence of sectors of plutonium contamination in the deep-
water area of Standley Lake attributable to "accidental" releases from the
Rocky Flats Plant.
As a follow-up to these findings, the subject sediment investigation was. con-
ducted to document changes in the plutonium contamination of the sediment bed
of Great Western Reservoir over the intervening period of three years - September,
1970, to October, 1973. Additionally, extensive sampling of Standley Lake
sediment was conducted to confirm the presence or absence of contaminated areas.
To differentiate between sediment contamination caused by plutonium releases
from the Rocky Flats Plant versus that resulting from worldwide fallout, sedi-
ment samples were collected on April 18, 1974, from Cherry Creek Reservoir,
Marston Lake, and Ralston Reservoir. Considering the predominant wind direction
and the distances from the plant to the reservoirs, sediment contamination in
these reservoirs attributable to gaseous effluents or windborne sources (con-
taminated soil) originating at the Rocky Flats Plant was considered negligible.
The three impoundments are not impacted by liquid effluents from the plant.
- 1 -
-------
SAMPLE COLLECTION AND ANALYSIS
PROCEDURES
Bottom sediment sampling stations in Great Western Reservoir and Standley
Lake are shown in Figures I and II. For these stations, the collection of
dredge samples was predominent with this type collected at 37 of the 39
stations. However, the majority of the stations (21 of 39) were also char-
acterized by the collection of both core and dredge samples. Dates of sedi-
ment collection for Great Western Reservoir and Standley Lake were October 18
and 25, respectively. Personnel from the Colorado Department of Health assisted
in the collection of samples from these two .impoundments.
Baseline sediment samples were collected from Cherry Creek Reservoir, Marston
Lake, and Ralston Reservoir on April 18, 1974. Specific sampling locations
are listed in Table I. For these impoundments, sampling was limited to
dredge samples.
Dredge samples were collected by the use of a Peterson dredge (without weights).
To obtain the composite dredge sample for radiological analysis, the below
procedure was followed:
(1) The sediment sample contained in the jaws of the dredge was emptied into
a pan. Caution was exercised to remove the collected sample as a layer
with as little disturbance as possible. The extent to which this was
achieved successfully depended on the cohesiveness of the sample.
(2) In the case of a fairly cohesive sample, the composite sample was prepared
from aliquots obtained by scraping the sample surface with a hand trowel.
For non-cohesive samples which underwent significant mixing in the closed
dredge as well as in the process of being removed from the dredge, the
composite sample was prepared from aliquots judged to be representative
of the overall sample texture. That is, an attempt was made to duplicate
the relative percentages of clay-like materials, silt, coarse materials
(gravel, etc.) and fines (sand).
Duplicate composite samples were prepared at all locations for analysis by
the Colorado Department of Health and EPA.
A Phleger Gravity Corer(a) was used to collect all but three core samples.
Shallow water depths at Stations 1, 2, and 4 in Great Western Reservoir pre-
vented the use of the corer. These samples were collected by manually pushing
the plastic core tube into the sediment bed. At all stations, field measure-
ments of the depth of penetration of the corer and the corresponding length
of the collected sample were taken to indicate the relative degree of compaction
during the collection procedure. Core samples were maintained in the frozen
(a) Equipped with a 2' metal coring tube which housed a plastic core tube
(1.5 inch inside diameter).
- 2 -
-------
0 0.5
Kilometers
FIGURE I
BOTTOM SEDIMENT SAMPLING STATIONS
GREAT WESTERN RESERVOIR
OCTOBER 18, 1973
-------
FIGURE E
BOTTOM SEDIMENT SAMPLING STATIONS
STANDLEY LAKE
OCTOBER 25, 1973
Of
J
• 7
• II *15
CO
• 12
•8
016
H3
• 9
©17
©14
OIO
0
u
KILOMETERS
2
-I
-------
TABLE I
SEDIMENT SAMPLING STATIONS
CHERRY CREEK RESERVOIR,, MARSTON LAKE, AND RALSTON RESERVOIR
Reservoir
Station
Number
Location
Cherry Creek Reservoir
CC-1
Approx. 180 meters from the
{approximately 24 miles southeast
inlet
of the Rocky Flats Plant)
CC-2
Approx, 90 meters from
the dam
Marston Lake
M-l
Approx. 45 meters from
the inlet
(approximately 19 miles southeast
of the Rocky Flats Plant)
M-2
Approx. 45 meters from
the inlet
Ralston Reservoir
R-l
Approx. 45 meters from
the head
(approximately 3 miles south of
end (mouth of Ralston
Creek)
the Rocky Flats Plant)
R-2
Approx. 0.4 kilometers
from the
head end
R-3
Approx. 0.8 kilometers
from the
head end (equidistant
between
the head end and the dam)
R-4 Approx. 0.4 kilometers from the
dam
R-5 Approx. 45 meters from the dam
- 5 -
-------
state during the interim period between collection and processing.A
selected number of core sections were provided to Dow Chemical Company for
their own analyses.
All EPA samples were analyzed in the Office of Radiation Programs radiochemistry
laboratory, National Environmental Research Center, Las Vegas, Nevada. Dredge
samples were analyzed for plutonium-238 and 239, cesium-137, beryllium, and
potassium; selected samples also were analyzed for strontium-89 and 90. Core
sections were analyzed for plutonium-239 with selected sections also analyzed
for plutonium-238 and beryllium.
(a) The process of "sectioning" each core sample initially involved thawing
the sample and subsequently forcing the water out of the tube by pushing
the sediment core upward with a metal plunger (core tube in a vertical
position). The core sample was then sectioned by a stepwise process of
pushing the sediment core upward and out of the tube, the exposed incre-
ment or step in each case being equal to the desired length of the core
section. During the sectioning process, the core tube was held in a
vertical position and the desired core section was pushed into an inverted
glass jar held at the end of the tube. A wide-blade knife was used to
cut each section.
- 6 -
-------
RESULTS
Plutonium-239 results for core and dredge samples from
the five impoundments - Cherry Creek Reservoir, Marston
Lake, Ralston Reservoir, Standley Lake, and Great Western
Reservoir - are presented in Tables II - IV. The plutonium-
239 results for dredge samples from Great Western Reservoir
and Standley Lake also are shown in Figures III and IV.
Analytical data for other parameters (cesium-137, strontium-
89 and 90, plutonium-238, beryllium and potassium) are
presented in Appendix A.
Physical descriptions of the core samples, including compaction
measurements, and corresponding photographs of the samples
prior to "sectioning" are compiled in Appendix B. The com-
positions of dredge samples from Cherry Creek Reservoir,
Marston Lake, and Ralston Reservoir are described in this
same appendix.
- 7 -
-------
.TABLE II
PLUTONIUM CONCENTRATIONS IN SEDIMENT SAMPLES
RESERVOIRS IN THE DENVER METROPOLITAN AREA
Approximate
Water Depth Plutonium-239
Reservoir and Station (meters) (pCi/qram)(a)
CC-1
4.5
<0.01
CC-2
6.0
<0.05
Lake
M-l
3.6
<0.02. „
M-2
4.5
0.13(b)
Reservoir
R-l
2.4
<0.06
R-2
1.5
0.03
R-3
24
<0.03
R-4
33
0.04
R-5
33
0.06
(a) Dry weight basis
(b) Result verified by replicate analysis
- 8 -
-------
TABLE III
PLUTONIUM CONCENTRATIONS IN SEDIMFNT SAMPI FS
STANDLEY LAKE
Station
1
2
3
4
6
7
8
9
10
11
12
13
Approximate
Water
Depth
(meters)
0.6
0.8
3.5
1.0
4.5
5.0
9.5
4.0
2.5
1.0
4.5
13
6.0
Dredge Sample
Plutonium-239
(pCi/gram) U)
0.11
0.04
0.05
0.04
0.08
0.08
0.15
0.08
<0.02
0.08
0.03
0.10
0.03
Core(b)
Section
_[cm]_
Core Sample
No Core
No Core
No Core
0 - 2.54
7.62 - 10.2
0 - 2.54
10.2 - 12.7
No Core
0 - 2.54
2.54 - 5.08
14.0 - 16.5
0 - 2.54
8.89 - 11.4
No Core
No Core
No Core
0 - 2.54
2.54- 5.08
17.8 - 20.3
Plutonium-239
(pCi/gram)(a)
<0.06
<0.04
0.08
<0.03
<0.06
<0.07
<0.08
<0.09
<0.07
0
7.62
2.54
10.2
0.10
<0.08
<0.03
<0.06
<0.06
(a) Dry weight basis.
(b) The limits of the range are measurements in centimeters from the top
surface of the core sample. No correction was made for compaction
during sample collection.
- 9 -
-------
TABLE III (continued)
Core Sample
Water Dredge Sample Core(k)
Approximate
Depth Plutonium-239 Section Plutonium-239
Station (meters) (pCi/gram) (cm) (pCi/gram)la)
14 6.0 0.08 No Core
15 6.0 <0.06 No Core
16
21
0.17
0 -
10.2 -
15.2 -
27.9 -
2.54
12.7
17.8
30.5
<0.10
0.11
0.07
<0.04
17
9.0
<0.03
0 -
5.08 -
2.54
8.89
<0.16
<0.04
- 10 -
-------
TABLE IV
PLUTONIUM CONCENTRATIONS IN SEDIMENT SAMPLES
GREAT WESTERN RESERVOIR
Station
1
3
4
9
10
11
12
Approximate
Water
Depth
(meters)
0.5
0.6
2.5
0.5
1.0
4.0
4.0
3.5
0.6
5.5
3.5
5.5
Dredge Sample
Plutonium-239
(pCi/gram)(a)
2.0
0.61
2.9
0.46
0.18
No Dredge
Sample
2.5
1.4
0.10
2.3
1.2
<0.06
Core(b)
Section
-------
TABLE IV (continued)
Core Sample
Station
Water
Depth 1
(meters)
Dredge Sample
Plutonium-239
(pCi/qram) U)
Core(b)
Section
(cm)
Plutonium-239
(pCi/gram)(a)
. 13
3.5
0.44
0 -
8.89 -
2.54
11.4
0.34
<0.06
14
9.5
4.1
0 -
2.54 -
17.8 -
2.54
5.08
20.3
2.6
2.2
<0.08
15
9.3
2.5
0 -
5.08 -
2.54
7.03
0.30
<0.07
16
4.5
0.62
0 -
3.81 -
11.4 -
3.81
6.35
14.0
1.3
0.35
<0.08
17
2.3
0.68
No Core
18
0,8
0.19
No Core
19
9.0
1.8
0 -
2.54 -
12.7 -
2.54
5.08
15.2
3.9
1.9
<0.04
20
12
3.8
0 -
1.91 -
13.7 -
1.91
3.18
16.2
3.8
4.4
<0.04
21(0
7.3
0.29
0 -
2.54 -
17.1 -
2.54
5.08
19.7
2.2
0.71
<0.04
22
No
Measurement
No Dredge
Sample
0 -
5.08 -
12.7 -
2.54
7.62
15.2
0.10
<0.10
<0.04
(c) As shown in Figure I, the core and dredge samples for this sampling station
designation were not collected in the same approximate location. The
dredge sample was collected more inshore in shallow water.
- 12 -
-------
Kilometers
FIGURE HI
PLUTONIUM-239(pCi/gram) IN DREDGE SAMPLES
GREAT WESTERN RESERVOIR
OCTOBER 18,1973
-------
FIGURE EZ:
PLUTONIUM-239(pCi/gram) IN DREDGE SAMPLES
STANDLEY LAKE
OCTOBER 25, 1973
i
®O.I5
® 0.03 • <0.06
O 0.10
1 0.08
® 0.17
• 0.03
• <$>.02
<0.03
• 0.08
•0.08
0
l_
KILOMETERS
2
-------
DISCUSSION
With one exception (Station M-2, Marston Lake), dredge samples from Cherry
Creek Reservoir, Marston Lake, and Ralston Reservoir contained plutonium-239
at concentrations substantially below 0.10 pCi/gram (Table II). This confirmed
previous findings leading to the conclusion that the baseline level of plutonium-
239 contamination in the bed sediment of area surface waters is typically less
than 0.10 pCi/gram. The sediment concentration of 0.13 pCi/gram obtained for
Station M-2 on Marston Lake was considered to be more of a spurious result than
a real concentration. The factors which could have contributed to a "high"
result were many. However, since the composite sample was analyzed in duplicate,
the reason was more probably one of sample collection and preparation as opposed
to analytical inaccuracies. That is, the composite sample prepared from the
Petersen dredge sample may have been biased in the percentage of "fines" and
somewhat unrepresentative of actual bed conditions.
Taken collectively, the plutonium-239 results for sediment samples collected
from Standley Lake did not indicate any discernible contamination attributable
to the Rocky Flats Plant (Table III). Only the dredge samples from Stations
7 and 16 showed concentrations slightly in excess of the established baseline
value (0.15 and 0.17 pCi/gram versus <0.10 pCi/gram). However, core samples
from these two locations were characterized by baseline levels in all anaylzed
sections. Accordingly, baseline conditions were concluded to be existent at
these two locations since the core samples were more representative of the
undisturbed sediment bed.(a) Analysis of core sections from all other sampling
locations also showed baseline concentrations of plutonium-239. Compared to
the findings of the 1970 study, the indication of possible contamination to a
depth of approximately 30 cm (compacted) in the deep water area near the dam
was not verified.
Plutonium-239 results for dredge samples and the top sections (<2.54 cm) of
the core samples showed contamination attributable to liquid wastes from the
Rocky Flats Plant over almost the entire bed of Great Western Reservoir (Table
IV). Consistent with the 1970 study, the zone or area of highest contamination
was the central section of the reservoir (inlet to dam). Areas of minimum
impact(b) were the south arm (Stations 5 and 12), the shallow-water, shoreline
area between the south arm and the dam (Station 21-dredge), and the western
portion of the north arm (Stations 9, 18, and 22). The major differences between
the 1970 and 1973 studies were the following:
(1) Over the three year period between sediment sampling efforts, the plu-
tonium-239 concentrations in the upper sediment layer increased signi-
(a) In comparison to a dredge sample, the core sample represents a relatively
undisturbed segment of the sediment bed. There is little mixing of sediment
particles in a vertical direction although significant compaction of uncon-
solidated material does occur.
(b) Plutonium-239 concentrations less than 0.30 pCi/gram.
- 15 -
-------
ficantly. Whereas the maximum concentration observed in 1970 was 0.86
pCi/gram, the October, 1973, study showed eleven (11) stations character-
ized by plutonium-239 concentrations greater than 1.0 pCi/gram. The
maximum concentration was 4.1 pCi/gram (Station 14).
(2) In contrast to the 1970 observation of maximum concentrations occurring
in the reservoir inlet area (adjacent to the mouth of Walnut Creek) the
1973 study showed maximum concentrations in the deep-water area of the
reservoir (Stations 14 and 20).
The core samples supported the previous finding of plutonium contamination
extending to depths of 5 cm or more (compacted) at most locations (Table IV).
Generalized, the typical concentration-sediment depth (thickness) profile
was one of decreasing concentrations with increased sediment thickness.
Comparing the Great Western Reservoir plutonium-239 results for dredge samples
with those for corresponding top sections of core samples showed no better
than "order-of-magnitude" agreement at each station. The reasons for the
lack of relatively close agreement in terms of absolute concentration values
are considered to be physical differences introduced by sampling techniques
and procedures. As noted in a previous footnote, the dredge and core collec-
tion procedures produce disturbed and undisturbed samples, respectively. The
other factor of importance was the field procedure involving the collection of
core samples as a separate activity following the completion of dredge sample
collection. This involved revisiting each sampling site a second time. Since
the location of each sampling station was determined by "eye" from references
to unique shoreline features, the sampling stations shown in Figure I repre-
sent general areas of limited size and not specific points. Hence, the dredge
and core samples for any given sampling location represented samples collected
from only the same general area and were expected to show variations in con-
centrations.
The cesium-137, strontium-89/90, plutonium-238, and beryllium data for core
and dredge samples from Great Western Reservoir and Standley Lake did not
indicate significant differences within a given impoundment or between the
two impoundments (Appendix A).
- 16 -
-------
SUMMARY
The October, 1973, sediment study of Standiey Lake and Great
western Reservoir and the April, 1974, sediment study of Cherry
Creek Reservoir, Marston Lake, and Ralston Reservoir produced
the following significant findings.
(1) In the environs of the Rocky Flats Plant, the base-
line level of plutonium-239 in the bed sediment of
impoundments is 4 0.10 pCi/gram (dry weight).
(2) Sediment throughout Standiey Lake was found to con-
tain plutonium-239 at baseline levels.
(3) Plutonium contaminated sediment attributable to the
routine discharge of plutonium-bearing liquid wastes
from the Rocky Flats Plant occurred throughout Great
Western Reservoir. Maximum concentrations in the top
layer of sediment (2.54 cm-- compacted) were approx-
imately 40X the baseline concentration; i.e. approx-
imately 4.0 pCi/gram (dry weight). The thickness of
the layer of plutonium-contaminated sediment was 5
cm or more at most sampling stations.
- 17 -
-------
REFERENCES
(1) U.S. Environmental Protection Agency, "Radioactivity
Levels In The Environs Of The Rocky Flats Plutonium
Plant, Colorado, 1970 - Part II" Technical Investigations
Branch, Surveillance and Analysis Division, Region VIII,
SA/TIB-26 (December 15, 1973).
- 18 -
-------
APPENDIX A
A - 1
-------
TABLE A-l
CESIUM-137. STRONIUM-89 AND 90, PLUTONIUM-238, BERYLLIUM, AND POTASSIUM IN DREDGE SAMPLES
GREAT WESTERN RESERVOIR AND STANDLEY LAKE
Station Concentration (Dry Weight Basis)
Cesi um-137
Strontium-89
Strontium-90
pWonium-238
Beryl 1ium
Potassium
; Western Reservoi r
(pCi/q)
(pCi/q)
(pCi/q)
(pCi/q)
(uq/q)
(uq/q)
1
1.0
<1.9
<0.82
<0.05
<2.0
29
2
0.97
<1.9
<0.82
<0.04
<2.0
27
3
1.1
<1.9
<0.82
0.05
0.6
29
4
0.52
<1.9
<0.82
<0.06
0.6
28
5
0.21
<1.9
<0.82
0.03
1.2
24
7
1.0
<1.9
<0.82
0.11
1.0
30
8
1.0
<1.9
<0.82
<0.06
1.0
22
9
0.17
-
-
<0.05
0.5
21
10
1.1
-
-
0.11
1.3
26
11
0.87
-
-
<0.04
1.2
27
12
1.3
-
-
<0.05
1.3
26
13
1.6
-
-
0.33
1.3
30
14
2.1
-
-
0.29
1.4
30
15
2.3
.
-
0.10
1.5
28
16
1.2
-
-
0.07
1.0
29
17
1.2
-
-
<0.06
0.7
28
18
0.94
-
-
0.06
0.9
29
19
1.4
-
-
<0.07
1.0
30
20
2.0
-
-
0.14
1.4
34
21
0.25
0.09
0.5
21
Standley Lake
1
2.3
_
-
<0.07
1.0
28
2
1.1
-
-
<0.06
0.9
23
3
1.0
-
-
<0.04
0.7
19
4
0.20
<2.0
<1.0
0.07
0.7
19
5
2.0
-
-
<0.11
0.9
29
6
2.3
-
-
<0.09
1.2
32
7
2.3
-
-
0.06
1.0
32
8
0.73
<2.1
<1.1
<0.03
0.9
26
9
0.26
<2.6
<1.3
<0.04
1.0
28
10
1.0
<2.2
<1.1
<0.05
0.9
20
11
0.58
-
-
<0.05
0.7
27
1Z
1.7
-
-
<0.04
1.4
30
13
0.68
<2.5
<1.2
<0.05
0.8
12
14
1.9
-
-
<0.03
1.3
26
15
0.91
-
-
<0.05
1.2
23
16
2.4
<2.3
<1.2
<0.06
2.0
35
17
0.70
-
-
<0.05
1.4
23
A - 2
-------
TABLE A-II
PLUTONIUM-238 AND BERYLLIUM IN CORE SAMPLES
GREAT WESTERN RESERVOIR AND STANDLEY LAKE
Station
Great Western Reservoir
Core(a)
Section
(cm)
Concentration (Dry Weight Basis)
PIutoni um-238 Beryl 1 ium
(pCi/g) (yq/q)
1
0
-
2.54
<0.04
<0.5
2.54
-
5.08
<0.05
<0.5
14.0
-
16.5
<0.06
0.6
2
0
_
2.54
0.04
0.6
2.54
-
5.08
<0.06
0.7
6.35
-
8.89
<0.04
0.8
4
0
_
3.49
<0.05
0.9
4.45
-
8.89
<0.05
1.1
5
0
_
2.54
<0.05
1.2
2.54
-
5.08
<0.04
0.9
7.62
-
10.2
<0.05
1.0
6
0
_
2.54
<0.05
1.2
2.54
-
5.08
<0.06
1.4
10.2
-
12.7
<0.06
1.1
7
0
_
2.54
<0.05
1.0
2.54
-
5.08
<0.05
0.9
12.7
-
15.2
<0.05
1.0
8
0
_
2.54
<0.06
1.0
2.54
-
5.08
<0.05
1.5
17.8
-
20.3
<0.05
1.0
13
0
2.54
<0.05
0.8
8.89
-
11.4
<0.06
0.7
14
0
2.54
<0.05
1.0
2.54
-
5.08
<0.06
1.8
17.8
-
20.3
<0.07
1.0
(a) The limits of this range are measurements in centimeters from the top
surface of the core sample. No correction was made for compaction
during sample collection.
A - 3
-------
TABLE A-II (continued)
Station
Great Western Reservoir
15
Core(a)
Section
(cm)
0
5.08
2.54
7.03
Concentration (Dry Weight Basis)
PIutonium-238 Beryllium
(pCi/g) (u9/9)
<0.05
<0.06
0.5
1.0
16
0
3.81
11.4
3.81
6.35
14.0
<0.05
<0.05
<0.07
0.9
0.9
1.0
19
0
2.54
13.7
2.54
5.08
16.2
0.05
<0.05
<0.05
1.7
1.3
1.4
20
0
1.91
13.7
1.91
3.18
16.2
0.08
<0.06
<0.05
1.9
1.3
1.3
21
22
Standiey Lake
4
5
7
8
12
0
2.54
17.1
0
5.08
12.7
0
7.62
0
10.2
0
2.54
14.0
0
8.89
0
2.54
17.8
2.54
5.08
19.7
2.54
7.62
15.2
2.54
10.2
2.54
12.7
2.54
5.08
16.5
2.54
11.4
2.54
5.08
20.3
<0.05
<0.05
<0.05
<0.05
<0.07
<0.05
<0.05
<0.04
<0.05
<0.05
<0.04
<0.06
<0.05
<0.08
<0.05
<0.04
<0.05
<0.05
1.2
0.7
1.2
0.8
0.9
1.0
<2.0
<2.0
<2.0
<2.0
<2.0
<2.0
<2.0
<2.0
<2.0
<2.0
<2.0
<2.0
A - 4
-------
TABLE A-II (continued)
Core(a) Concentration (Dry Weight Basis)
Section Plutonium-238 Beryllium
Station (cm) (pCi/q) (u g/g)
Standley Lake
13 0 - 2.54 <0.04 <2.0
7.62 - 10.2 <0.05 <2.0
16 0 - 2.54 <0.05 <2.0
10.2 - 12.7 <0.07 <2.0
15.2 - 17.8 <0.05 <2.0
27.9 - 30.5 <0.05 <2.0
17 0 - 2.54 <0.11 <2.0
5.08 - 8.89 <0.05 <2.0
A - 5
-------
APPENDIX B
B - 1
-------
CORE LOG
Great Western Reservoir
Station 1
Collection - Core collected by manually pushing the plastic
core tube into the sediment bed
Total penetration - 16.5 cm
Total core length - 16.5 cm
Description
0 - 5.08
cm
Silt and sand mixture; predominately
brown sand.
cn
o
00
1
1—»
o
ro
cm
Gradation from sandy composition to
clay.
10.2 - 16.5
cm
Brown clay.
B -2
-------
Station 2
Collection - Core collected by manually pushing the plastic core
tube into the sediment bed.
Total penetration - 8.89 cm
Total core length - 8.89 cm
Description
0 - 2.54 cm Loose, brown material; "flocculent-1ike."
Some black matter.
2.54 - 5.08 cm Same as top 2.54cm except for slight
increase in the amount of black matter.
5.08 - 8.89 cm Clay embedded with vegetation fragments
(roots, etc.)
Station 4
Collection - Core collected by manually pushing the plastic core
tube into the sediment bed.
Total penetration - 8.89 cm
Total core length - 8.89 cm
Description
0 - 3.49 cm Loose, brown sediment; "flocculent-1ike."
3.49 - 4.76 cm No description.
4.76 - 8.89 cm Predominately brown clay; some gray streaks.
B - 3
-------
Station 5
Collection - Phleger Gravity Corer
Total penetration - 12.7 cm
Total core length - 12.7 cm
Description
0 - 5.08cm Unconsolidated silt; brown color.
Some decaying organic matter; black color.
5.08 - 12.7 cm Clay with some sand and plant detritus.
B - 4
-------
.Station 6
Collection - Phleger Gravity Corer
Total penetration - 28.7 cm
Total core length - 15.2 cm
Description
0 - 2.54 cm Silt and sand; predominately sand,
brownish-black.
2.54 - 5.08 cm Extremely thin overlay of sandy material
on grayish-brown clay.
5.08 - 7.62 No description.
7.62-15.2 cm Grayish-brown clay.
B - 5
-------
Station 7
Collection - Phleger Gravity Corer
Total penetration - 26.0 cm
Total core length - 17.1 cm
Description
0 - 2.54 cm Unconsolidated silt; brownish-black.
2.54 - 5.08 cm Transition zone from silt to clay. The
unconsolidated silt extended in an irregular
pattern to depths of 3.81 to 4.45cm.
5.08 - 12.7 cm No description.
12.7 - 17.1 cm Brown clay with gray flecks.
B - 6
-------
Station 8
Collection - Phleger Gravity Corer
Total penetration - 40.6 cm
Total core length - 25.4 cm
Description
0 - 5.08 cm Dark brown silt.
5.08 - 8.89 cm Gradation from dark brown silt to light
gray clay. Gravel in the clay at a depth
of 7.62 cm.
8.89 - 14.0 cm Gradation from light gray clay to light
brown clay.
14.0 - 25.4 cm Light brown clay interspersed with chunks
of sand and gravel.
B - 7
-------
Station 13
Collection - Phleger Gravity Corer
Total penetration - 22.2 cm
Total core length - 14.6 cm
Description
0 - 2.54 cm Mixture of dark brown silt, sand, and
gravel.
2.54 cm - 5.08 cm Gradation to gray clay.
5.08 - 14.6 cm Gray clay.
B - 8
-------
Station 14
Collection - Phleger Gravity Corer
Total penetration - 48.3 cm
Total core length - 23.5 cm
Description
0
- 5.08
cm
5.08
- 12.7
cm
12.7
-23.5
cm
Black matter; organic.
Gradation from black matter to clay
(mixture of brown and gray).
Grayish-brown clay.
B
-------
Station 15
Collection - Phleger Gravity Corer
Total penetration - 10.8 cm
Total core length - 9.53 cm
Description
0 - 1.91 cm Unconsolidated, dark brown silt.
1.91 - 3.81 cm Gradation to light brown clay.
3.81 - 9.53 cm Light brown clay.
B - 10
-------
Station 16
Collection - Phleger Gravity Corer
Total penetration - 25.4 cm
Total core length - 16.5 cm
Description
Sandy clay; dark brown color; pebbles
throughout the core.
Station 19
Collection - Phleger Gravity Corer
Total penetration - 73.7 cm
Total core length - 22.2 cm
Description
0
- 1.91
cm
Dark brown sediment; "flocculent-1ike."
1.91
- 9.53
cm
Mixture of black and dark brown sediment
9.53
- 12.1
cm
Gradation to grayish-brown clay.
12.1
- 14.6
cm
Gradation to gray clay.
14.6
- 15.2
cm
Gradation to brown clay.
15.2
- 16.5
cm
Brown clay.
B - 11
-------
Station 20
Collection - Phleger Gravity Corer
Total penetration -114.3 cm
Total core length - 27.9 cm
Description
0 - 1.91 cm Dark brown sediment; "light-weight"
material.
1.91 - 3.18 cm Band of light brown clay.
3.18 - 10.2 cm Grayish-black matter; some areas of
dark brown color.
10.2 - 27.9 cm Dark gray matter; "ooze."
Note: The core was very fluid after thawing.
Cross contamination among sections may
have occurred.
B - 12
-------
Station 21
Collection - Phleger Gravity Corer
Total penetration - 71.1 cm
Total core length - 22.2 cm
Description
0 - 2.54 cm Unconsolidated, dark brown silt.
2.54 - 5.08 cm Gradation to gray matter.
5.08-15.2 cm Dark gray matter.
15.2 - 22.2 cm Gray clay (the surface of the core
was yellowish-brown; coloring possibly
carried down from the surface layer).
B - 13
-------
Station 22
Collection - Phleger Gravity Corer
Total penetration - 17.8 cm
Total core length - 17.8 cm
Description
0 - 3.18 cm Thin layer of dark brown silt overlaying
sand and gravel. Some plant detritus.
3.18 - 5.72 cm Gradation to brown clay; some roots.
5.72 - 17.8 cm Brown clay; some rocks and gravel.
Roots in the bottom 2.54 cm.
B - 14
-------
Standiey Lake
Station SL-4
Collection - Phleger Gravity Core
Total penetration - 10.2 cm
Total core length - 10.2 cm
Note: Roots throughout the length of the core.
Description
0 - 5.08 cm
5.08-10.2 cm
Silt and fine sand.
Brown clay.
B - 15
-------
Station SL-5
Collection - Phleger Gravity Core
Total penetration - 41.9 cm
Total core length - 15.2 cm
Description
0 - 4.45 cm Silt overlaying grayish-brown clay.
4.45 - 10.2 cm Grayish-brown and brown clay.
10.2 - 15.2 cm Predominately sand; very little clay.
B - 16
-------
Station SL-7
Collection - Phleger Gravity Corer
Total penetration - 30.5 cm
Total core length - 19.1 cm
Description
0 - 2.54 cm Dark brown silt.
2.54 - 19.1 cm Sand-clay mixture grading to sand.
Station SL-8
Collection - Phleger Gravity Corer
Total penetration - 15.2 cm
Total core length - 14.0 cm.
Description
0 - 2.54 cm Silt and sand.
2.54 - 5.08 cm Sand and grayish-brown clay.
5.08 - 8.89 cm Grayish-brown clay; some sand.
8.89 - 14.0 cm Light to dark brown clay; some sand.
B - 17
-------
Station SL-12
Collection - Phleger Gravity Corer
Total penetration - 22.9 cm
Total core length - 22.9 cm
Description
0 - 5.40 cm Sandy silt; dark brown.
5.40 - 5.72 cm Gradation to grayish-brown clay.
5.72-14.0 cm Gradation: grayish-brown clay to
brown clay.
14.0 - 22.9 cm Brown clay.
B - 18
-------
Station SL-13
Collection - Phleger Gravity Corer
Total penetration - 17.8 cm
Total core length - 12.7 cm
Description
0 - 3.18 cm Dark brown silt and sand; largely
silty sand.
3.18 - 5.08 cm Gradation to brown clay.
5.08-12,7 cm Brown clay.
B - 19
-------
Station SL-16
Collection - Phleger Gravity Corer
Total penetration - 116.8 cm
Total core length - 43.2 cm
Description
0 - 25.4 cm Black "ooze;" "greasy."
The section defined by depth limits
of 2.54 to 5.08cm contained a considerable
amount of plant detritus.
25.4 - 43.2 cm Clay mixed with the black "ooze."
Coloration of clay ranged from gray to
grayish-brown.
B - 20
-------
Station SL-17
Collection - Phleger Gravity Corer
Total penetration - 22.9 cm
Total core length - 11.4 cm
Description
.0 - 3.81 cm Dark brown silt and sand.
3.81 - 5.08 cm Gradation to light brown clay.
5.08 - 11.4 cm Light brown clay containing sand
gravel.
B - 21
-------
TABLE B-I
SEDIMENT SAMPLE COMPOSITION
CHERRY CREEK RESERVOIR, MARSTON LAKE, AND RALSTON
RESERVOIR
Station
Cherry Creek Reservoir
CC-1
CC-2
Marston Lake
M-l
M-2
Ralston Reservoir
R-l
R-2
R-3
R-4
R-5
Composition
Gray silt
Gray and black silt
Silt and sand
Brown and gray silt
Mixture of sand and gray
silt
Brown and gray silt
Brown and gray silt
Brown and gray silt
Gray silt
B - 22
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
!1 REPORT NO.
EPA-908/2-75-001
2.
3. RECIPIENT'S ACCESSIOf^NO.
:4. TITLE AND SUBTITLE
i Plutonium Levels in the Sediment of Area Impoundments
5. REPORT DATE
i Environs of the Rocky Flats Plutonium Plant - Colorado
:
H
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
1.
I Milton W. Lammering, Ph.D.
8. PERFORMING ORGANIZATION REPORT NO.
S&A/TIB-29
•9 PERFORMING ORG "\NJZATION NAME AND ADDRESS
Technical Investigations Branch
| Surveillance & Analysis Division
| U.S. Environmental Protection Agency, Region VIII
i Denver, Colorado 80203
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
•12. SPONSORING AGENCY NAME AND ADDRESS
j
13. TYPE OF REPORT AND PERIOD COVERED
Investigations 1973
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
[16. ABSTRACT :
Plutonium concentrations in the bed sediment'of reservoirs (Great Western Reservoir,
Standley Lake, Cherry Creek Reservoir, Marston Lake, and Ralston Reservoir) in the
environs of the Atomic Energy Commission Rocky Flats Plant were determined by dredge
and core sampling. Great Western Reservoir and Standley Lake were sampled during
October, 1973; the other three impoundments during April, 1974. The baseline level
of plutonium-239 in bed sediment attributable to worldwide fallout was found to be
4 0.10 pCi/gram (dry weight). Correspondingly, the maximum concentrations in the
top layer of sediment in Great Western Reservoir were approximately 4.0 pCi/gram (dry
weight). The thickness of the layer of plutonium-contaminated sediment in the re-
servoir was 5 cm or more at most sampling stations. Through 1973, Great Western
Reservoir received liquid wastes (plutonium-bearing) from the Rocky Flats Plant via
the tributary stream, Walnut Creek.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATl Field/Group
Plutonium-239, bed sediment, AEC Rocky
Flats Plant.
Radiological contaminatic
sediment accumulation.
n,
18. DISTRIBUTION STATEMENT
Release to the Public
19. SECURITY CLASS (This Report)
unclassified
21. NO. OF PAGES
49
20 SECURITY CLASS (This page)
unclassified
22. PRICE
EPA Form 2220-1 (9-73)
------- |