&EPA
United States
Environmental Protection
Agency
Environmental Research
Laboratory
Duluth MN 55804
EPA 600 3 79 008
i (>79
Research and Development
Environmental
Effects of Western
Coal Surface
Mining
Part III
The Water Quality of
Trout Creek,
Colorado
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development. U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3 Ecological Research
4. Environmental Monitoring
5 Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
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9 Miscellaneous Reports
This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161,
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EPA-600/3-79-008
January 1979
ENVIRONMENTAL EFFECTS OF WESTERN COAL SURFACE MINING
Part III - The Water Quality of Trout Creek, Colorado
by
R. K. Skogerboe, C. S. Lavallee, M. M. Miller, and D. L. Dick
Department of Chemistry
Colorado State University
Fort Collins, Colorado 80523
Grant No. R803950
Project Officer
Donald I. Mount
Environmental Research Laboratory
Duluth, Minnesota 55804
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
DULUTH, MINNESOTA 55804
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DISCLAIMER
This report has been reviewed by the Environmental Research Laboratory-
Duluth, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or recommendation
for use.
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FOREWORD
The appearance of surface coal mines is aesthetically displeasing to
many and as a result, conclusions are reached about their environmental impact
that are not supportable. This report documents the changes in concentrations
of various elements and salts in surface water as a result of surface mining
in Colorado. Data has been gathered to show the effect of aging of spoils,
changes in ground water quality and effects of various mine practices on
surface waters.
Only after objective conclusions from valid data are made can good
regulatory decisions be made. Our objective is to find the least environ-
mentally damaging methods to obtain fuel, in this case coal, for our growing
energy demands.
Donald I. Mount, Ph.D.
Di rector
Environmental Research Laboratory-Duluth
iii
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ABSTRACT
Water quality parameters have been measured at several on-stream and
off-stream sites along Trout Creek, which is recipient of water from coal
strip-mining operations. Levels of the gross parameters (e.g., specific
conductivity), the common ions (e.g., calcium and sulfate), and some trace
components (e.g., selenium) are highest in mine spoil drainages.
The impact of the mine spoil drainage on the stream is reflected in the
larger quantities of dissolved solids and common ions found at on-stream
sites adjacent to and below the mine. For trace elements, the mine operation
has no detectable impact on Trout Creek in terms of increasing concentrations
of Al, As, Cd, Cr, Cu, Fe, Pb, or Zn. Increases in stream concentrations of
Mn and Se due to mine inflow can be inferred from the data. Higher concen-
trations of As, Fe, Mn, Se, and Zn are found in waters draining mine spoils.
In the mine spoils, variations in the concentrations of these elements occur
with spoil age; more Mn and Zn occur in older spoils, while higher levels of
As, Fe, and Se are found in newer spoils.
Chemical equilibrium calculations indicate that alkaline precipitation
processes can maintain the low concentrations of Al, Cd, Cu, Fe, Pb, and Zn.
The general alkaline characteristics of western streams and aquifers suggests
that such precipitation equilibria will limit the soluble heavy metal
concentrations.
IV
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CONTENTS
Foreword iii
Abstract iv
Figures vii
Tables ix
Acknowledgments x
I Introduction 1
II Conclusions 2
III Recommendations 4
IV Site Selection 5
Description of the Study Area 5
Physical characteristics 5
Geology 7
Hydrology 12
Monitoring Sites 12
V Methods and Procedures 16
VI Results and Discussion 17
Stream Discharge Patterns 17
Water Quality Differences within the Mine 17
Stream Water Quality; Gross Parameters and
Common Ion Impacts 21
Heavy Metal Impacts ' 32
Manganese 39
Copper 39
Mercury 39
Selenium . 42
Zinc 42
Arsenic 42
Iron 42
Summary 43
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Page
VII Evaluation of Chemical Equilibria 44
References 56
VI
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FIGURES
Number Page
1 Location of map of the mine study site 6
2 Schematic east-west cross-section near station C6 8
3 Geologic map of the Edna Mine and surrounding area 9
4 Generalized columnar section of exposed rocks in the
area of Trout Creek, Colorado 10
5 Location map of water quality monitoring stations
and mine surface watersheds in the study area 13
6 Typical stream discharge data at Trout Creek 18
7 Specific conductivity of surface waters at sites associated
with various stages of spoil weathering 19
8 Specific conductivity of surface waters above (C2) and
adjacent to the mine (C6) 22
9 Spatial and temporal distribution of dissolved solids 24
10 Spatial and temporal distribution of hardness 25
11 Spatial and temporal distribution of calcium concentrations ... 26
12 Spatial and temporal distribution of magnesium concentrations . . 27
13 Spatial and temporal distribution of sulfate concentrations ... 28
14 Spatial and temporal distribution of sodium concentrations .... 29
15 Spatial and temporal distribution of potassium concentrations . . 30
16 Spatial and temporal distribution of chloride concentrations ... 31
17 Elemental detection limits, observed concentration ranges,
frequency of occurrence above detection limits, and average
concentrations in surface waters above and below the Edna Mine . . 38
vi i
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18 Elemental detection limits, observed concentration ranges,
frequency of occurrence above detection limits, and
average concentrations of subsurface waters in the Edna Mine ... 40
19 Solubility of metals under typical natural water conditions ... 50
20 Solubility of metals under typical natural water conditions ... 51
viil
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TABLES
Number Page
1 Analyses of coal samples from the Edna Mine 11
2 Description of the water quality sampling stations 14
3 Average values of water quality parameters associated with
subsurface waters from mine spoils of various ages 20
4 Equilibria and equilibrium constants considered 1n model
calculations 33
5 Quality criteria for water 41
6 Comparison of calculated and observed maximum concentrations
at stream and mine spoil drainage sites 47
7 Summary of acid-base buffer capacities 53
8 Primary chemical forms of soluble metals predicted by the
equilibrium computations 54
ix
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ACKNOWLEDGMENTS
The field studies reported herein were carried out with the full coop-
eration of the Pittsburg and Midway Coal Mining Company. These operators
voluntarily contributed man power and equipment to the project on several
occasions. Their assistance is greatly appreciated.
The authors would also like to thank Dr. D. B. McWhorter of the Agricul-
tural Engineering Department of Colorado State University for helpful
discussions.
This research was funded in part by U.S. Environmental Protection Agency
Grant No. R802175 and by the U.S. Environmental Protection Agency, Environ-
mental Research Laboratory-Duluth, Research Grant No. R803950, awarded to
Natural Resource Ecology Laboratory, Colorado State University, and Fisheries
Bioassay Laboratory, Montana State University.
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SECTION I
INTRODUCTION
The overall objective of the present investigation has been to provide
predictive information regarding the potential effects of western strip coal
mining on surface water quality and the concomitant impacts on the aquatic
biota. Major subobjectives have included the establishment of data bases for
evaluating the potential impact of coal extraction on fresh water resources
and ecosystems, the use of chemistry and biology field studies to assess the
nature and extent of effects on aquatic ecosystems, and the determination of
acute and chronic toxicity and bioaccumulation of contaminants involved. The
general research plan has consequently embodied: the chemical characteriza-
tion of effluents from coal mining sites, evaluation of the impacts of these
effluents on surface water quality, and the identification of known and
potential toxicants resulting from mining operations. In addition, evalua-
tion of the mechanistic parameters which define the routes of transfer and
control the rates and amounts of transfer of toxicants between the mine
source(s) and surface waters has been considered.
To accomplish these objectives, field studies dealing with the chemical
characteristics of surface water and groundwater associated with a coal
mining site have been carried out over a period in excess of two years.
These have been coordinated with fish and macroinvertebrate distribution
studies at the same site. The fish distribution study results have been
summarized by Goettl and Edde (1979) while the macroinvertebrate results have
been reported by Canton and Ward (1978). The present report summarizes the
water quality impact assessment.
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SECTION II
CONCLUSIONS
1. Inflow of surface water and groundwater from the coal mine causes
overall decreases in the water quality of Trout Creek. In general, a
flow increase of X% between sites above and adjacent to the mine is
usually accompanied by an increase in total dissolved solids of 2X% or
more. During the spring runoff due to snowmelt at the mine, this
situation is exaggerated. A flow increase of Y% between the stream
sites above and adjacent to the mine may be accompanied by total
dissolved solids increases as high as 50Y5L
2. The increases in dissolved solids observed appear to be dependent on the
extent of weathering that the disrupted strata of the mine have under-
gone. For recently exposed strata, increases in sodium, alkalinity, and
sulfate are predominant. For strata which have been exposed longer,
calcium, magnesium, alkalinity, and sulfate concentrations predominate.
Consequently, exposure of the strata results in water quality decreases
which are initially influenced by dissolution of sodium salts; when
these are depleted, the less soluble calcium and magnesium salts control
the equilibria. The latter are thus responsible for the long-term
effects on water quality.
3. Spatial and temporal variations in the dissolved solids, specific con-
ductivity, hardness, calcium, magnesium, sodium, potassium, sulfate, and
chloride all exhibit the same pattern as the recipient stream progresses
past the mine. Levels are lowest at sites above all mining, increase to
maxima at sites of maximum inflow from the mine, and decline at sites
downstream of the mine. The highest impacts on the water quality occur
during the spring snowmelt at the mine elevation.
4. The mine operation has no detectable impacts on Trout Creek in terms of
significant increases in the concentrations of Al, As, Cd, Cu, Fe, Pb,
and Zn.
5. Significant increases in the stream concentrations of Mn and Se due to
the mine inflow can be inferred from the data. Although these increases
occur, their magnitudes are such that significance in terms of potential
impacts on aquatic biota does not appear likely. Exception to this may
occur at a mine pond draining an exposed cut.
-------
6. In terms of the groundwater Impacts, higher concentrations of several
elements, e.g., Fe, Mn, and Zn, are associated with subsurface waters In
equilibrium with the oldest spoils. The reverse appears true for Cd,
Cr, and Cu but the data are much more limited. Higher levels of As, Hg,
and Se are associated with groundwater in equilibrium with the less
weathered spoils.
7. Chemical equilibrium calculations indicate that the concentrations of
Al, Cd, Cu, Fe, Pb, and Zn can be maintained at or below the levels
observed by precipitation processes. These are largely hydroxide and/or
carbonate precipitation reactions. The concentrations of these pre-
cipitants are influenced by the mine operation such that maintenance of
these controlling equilibria may be very long-term. The generally basic
and alkaline characteristics of western streams and aquifers, coupled
with the fairly universal influx of alkaline constituents from most
western coal mine operations, suggest that such precipitation equilibria
will limit possible heavy metal impacts in the western coal development
region.
8. Water quality conditions, specifically characteristic of the Trout Creek
site and generally characteristic of the western coal development area,
allow the prediction of the principal soluble forms of heavy metals via
chemical equilibrium evaluations. The primary soluble forms are expected
to be either a simple aquated form (e.g., Zn+2/aq)) or a hydrolyzed form
(e.g., Fe(OH)2+). For some elements (e.g., Cu), soluble complexes
involving carbonate may also be important. At sites where the sulfate
levels exceed approximately 400-500 mg/liter, the solubilities of Mn,
Pb, and Zn may be enhanced due to the formation of sulfate complexes.
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SECTION III
RECOMMENDATIONS
The data collected during the study period show a significant increase
in total dissolved solids in the mine area. By comparing the sites which
reflect runoff from recontoured spoils to those which remain ungraded, it is
apparent that returning the spoils to their original contour reduces the
extent of percolation through the spoils and consequently the impact on water
quality. It is therefore recommended that leveling take place as quickly as
possible after the mining operations are completed. Revegetation of these
recontoured spoils will further prevent percolation and subsequent erosion.
It is also recommended that a vegetated buffer zone between recipient
stream and associated mining operations be maintained. Such undisturbed
areas serve to further reduce the impact of mine drainage on recipient
streams.
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SECTION IV
SITE SELECTION
Several factors were considered in the selection of the study site. The
Edna Coal Mine and the recipient stream, Trout Creek, were chosen for study
on the following bases. The mine operation is such that a gradation of aged
(weathered) to new spoils could impact the stream as it progresses along the
mine. Groundwater and surface water hydrology as well as a reasonable amount
of chemical data were available. The stream originates in a pristine area
immediately above the mine such that reference point (baseline) measurements
could be made. Finally, the mining activities were likely to be the prin-
cipal cause of any water quality and aquatic biology changes observed.
DESCRIPTION OF THE STUDY AREA
The area has been previously described by McWhorter et al. (1975). The
description has been summarized here for the convenience of the reader.
Physical Characteristics
The area has been described by Bass et al. (1955). It lies in north-
western Colorado in the southeastern portion of a gently rolling, 2,590 km2,
coal mining region known to the industry as the eastern part of the Yampa
coal field. The climate is semiarid with an annual precipitation of 38 to
51 cm; at least half of this occurs as snow.
Trout Creek is west of the town of Oak Creek and southwest of Steamboat
Springs (Figure 1). It originates in a mountain region at an elevation in
excess of 3550 m, runs several kilometers through national forest, enters a
small valley containing Pittsburgh and Midway's Edna Mine, and continues
northward to its confluence with the Yampa River near Milner, Colorado. At
the higher elevations above the mine, the land is largely vegetated with
trees and native grasses. In the valley, vegetation changes to native
grasses and some alfalfa fields. Stock ranches utilize the land across the
creek and downstream from the mine.
It may be noted in Figure 1 that mining started on the upstream side in
the World War II era. Although the strata disrupted by mining In the older
area have not been regraded to their original aspect, the area is sparsely
vegetated in native scrubbrush (oak) and grasses. Mining operations then
moved progressively north, reaching the northern extreme around 1970; these
latter were the first spoils to be regraded to the original contours and are
-------
Apex Mine
(underground)
' Steamboat
Springs
Denver*
COLORADO
i;
'I
t
Kilometers
5 10 ;
I
1
5
Miles
10
Figure 1. Location map of the mine study site. Inset indicates
location in Colorado.
-------
now partially vegetated with native plants. Current activity is centered on
the upslope (east) side of the mine near the top of the ridge separating the
Oak and Trout Creek watersheds.
The area mined during the 1950's includes a bowl-shaped cut, about
200 m2 x 30 m deep, near the base of the spoils that is barren of vegetation.
With this exception, the density of native vegetation is approximately
proportional to the age of the spoil material.
A cross-sectional diagram of the slope after mining is given in Figure 2.
The mine slopes to the creek at approximately 10°. The surface material is
composed largely of mine overburden which is the only soil layer above bed-
rock. Below the surface, which is graded only in the northern end of the
mine, the overburden consists of debris ranging in size from that associated
with clays to rocks 1 m in diameter. This material normally ranges from 10
to 20 m in depth and represents a marked contrast to the relatively well-
sorted soils and strata present prior to mining. The mine is typically
separated from the creek by approximately 50 m of undisturbed area which
serves to some extent as a buffer zone through which mine drainage must pass.
Geology
The geology of the site has been summarized by Campbell (1923) (see
Figure 3). This indicates that the Trout Creek and Little Trout Creek water-
sheds above the mine are principally of the lies formation. The mine portion
of the area and downstream from it are of the Williams Fork formation. Thus,
the groundwater input above the mine represents an equilibrium situation
reflective of a different geological formation than that directly associated
with the mine.
The strata included in the above formations are depicted in Figure 4.
In the study area, the sandstone member immediately above the Williams Fork
formation has been eroded away. The remaining strata lies on a 10° slope
toward the creek (Figure 2). However, several of the strata contained in the
lies and the Williams Fork formations are similar, and both contain shale,
sandy shale, and limy shale (Figure 4). Differences in terms of depths and
proportions of these strata within the lies and the Williams Fork formations
could account for differences in groundwater characteristics associated with
these two formations; these differences are not expected to be large.
The coal deposits associated with the Williams Fork formation at the
mine are of the middle coal group; the Lennox and Wadge seams have been mined
most extensively. These coals have ash contents between 5% and 9% and sulfur
levels ranging from 0.5% to 3% (see Table 1).
Soils in the undisturbed areas are generally poorly developed; bedrock
frequently occurs within 1 m of the surface and is overlain by a layer of
clay. These two factors limit the penetration of precipitation into the
underlying strata in undisturbed areas; mining makes the strata accessible to
a much higher degree (Goettl and Edde 1979).
-------
Highwall
00
Madge
Seam
Undisturbed Bedrock
Oak
Creek
Figure 2. Schematic east-west cross-section near station C6 (taken from report by McWhorter et al.
1975).
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Le
F
'.' V- ' ':'.'''
Q '*'".
1 * * * . '
* ".**.'.
i . ' t * ' iji^ "
*'°l!i' ' \'°.
'"*« * '*. * i
UlUJJi!l4iJJJi|l
' % '**% -
":-';''-,
*}:-!»
"'»'*%*'»
*** / s *
;Sj^5^S
wis Shale Williams Fork lies Mancos
ormation Formation Formation Shale
Figure 3. Geologic map of the Edna Mine and surrounding area
(McWhorter et al. 1975).
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tr-"ir ~ =-"=\J Dry Creekl Upper Coal
Sandstone
Lennox
Wadge
lolfcr
Group
>-Middle Coal
Group
Sandstone
1/1
QJ
E
. + '
>Lower Coal
Group
~ £^5S^^^S@:1 J Sandy Shale
Sandstone
Figure 4. Generalized columnar section of exposed
rocks in the area of Trout Creek, Colorado
(Bass et al. 1955).
10
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TABLE 1. ANALYSES OF COAL SAMPLES FROM THE EDNA MINE^/ (A = AS RECEIVED, B = AIR DRIED, C = MOISTURE-FREE, D = MOISTURE AND ASH-FREE)
Air-dry inc
Mine and location Formation loss
Edna strip mine, Edna Williams Fork 5.3
Coal Co., SEs sec. 24,
T. 4 N., R. 86 W.
Arthur mine (later known Williams Fork 2.7
as Edna) of John Arthur
SVfls sec. 24, T. 4 N.,
R. 86 W.
Form of
analysis
A
B
C
D
A
B
C
0
A
B
C
D
A
B
C
D
Moisture
11.0
6.0
10.1
8.5
9.9
5.0
-~
10.1
7.5
Proximate
Volatile
matter
36.5
38.6
41.0
43.4
36.4
37.1
40.5
43.6
39.9 *
42.1
44.3
46.4
38.4
39.5
42.7
46.9
Fixed
carbon
47.7
50.3
53.6
56.6
47.1
47.9
52.4
56.4
46.2
48.6
51.2
53.6
43.5
44.8
48.4
53.1
Ultimate
Ash
4.8
5.1
5.4
6.4
6.5
7.1
4.0
4.3
4.5
8.0
8.2
8.9
Sulfur
0.5
0.5
0.6
0.6
0.6
0.7
0.7
0.8
2.5
2.6
2.9
0.6
0.7
0.7
0.8
Hydrogen
5.9
5.6
5.2
5.5
5.8
5.7
5.2
5.6
__
5.9
5.7
5.3
5.8
Carbon
65.8
69.5
73.9
78.1
65.0
66.1
72.3
77.8
63.0
64.7
70.0
76.8
Nitrogen
1.3
.4
.5
.5
.4
.5
.6
.7
1.4
1.5
1.6
1.8
Oxygen
21.7
17.9
13.4
14.3
20.8
19.5
13.1
14.1
21.1
19.2
13.5
14.8
Heating values
Calories 8TU
11.640
12,290
13,070
13,820
11,400
11,600
12,670
13,640
..
6,228 11,210
6,400 11,520
6,922 12.460
7,600 13,680
'From Bass et al. (1955).
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Hydrology
Trout Creek is the major drainage of the 110 km2 watershed which
includes the mine. The hydrology of this drainage has been characterized by
McWhorter et al. (1975). The mean annual discharge measured just below the
mine has been estimated at 2.8 x io7 m3/yr. This is approximately equivalent
to a precipitation of 26 cm/yr over the watershed (McWhorter et al. 1975).
The surface water divides in the area coincide generally with the topographic
highs. In the spoil areas, the surface drainage patterns are disrupted in
several areas such that precipitation tends to accumulate in depressions and
infiltrate into spoils with little or no overland flow. Thus, a high frac-
tion of the precipitation is lost by evapotranspiration or infiltration into
the ground. It is clear that mining has changed the surface and subsurface
drainage patterns; this can be inferred from Figure 2. The depth to which
water can percolate has been generally changed from a few meters to more than
15-20 m; this increases the potential for the dissolution of spoil materials
by water. Although a highwall of undisturbed rock exists between the mine
and the creek, at least a small amount of subsurface flow from the mine
through the alluvial aquifers and into the creek occurs (McWhorter et al.
1975). The quantity of this underflow is not known. Small drainages enter
the creek from the ranch area opposite the mine but their contribution to the
total inflow is small. In general, the major inflow contributions to the
stream originate on the mined site.
Monitoring Sites
A total of 15 collection stations were established within the Trout
Creek watershed. These include:
1. on stream stations above, along, and below the mine;
2. a station on Little Trout Creek at its confluence with Trout Creek
which is fed largely by subsurface drainage not associated with
mining; and
3. stations on ponds and streams located in the mine proper.
The locations of these stations and the individual watershed boundaries
associated with stations within the mine are shown in Figure 5 while a more
detailed description is given in Table 2. It should be noted that the water-
shed boundaries coincide approximately with reasonably well defined stages of
the historic progression of the mining activity (see Figure 1).
The following points concerning these sampling stations should be noted.
1. The Cl and C2 sites are above all surface mining activity. It will
be shown below that the water quality parameters (WQP) measured at
these two sites are indistinguishable. This indicates that the
underground mine (Figure 1) located between them has no impact on
the stream and that the WQP measurements at C2 serve as reliable
references for deduction of impacts which may occur downstream.
12
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TABLE 2. DESCRIPTION OF THE WATER QUALITY SAMPLING STATIONS
Trout Creek
urface water
Cl
C2
I
v
_
>-*
n
\
C4
C6
C8
Cll
C14
Station number and character
Intermittent Mine drainage Subsurface Date
Little Trout Creek streams pools in water sampling
surface water in spoils spoils drainage started
Oct. 1973
Oct. 1973
C13 July 1975
C3 Oct. 1973
C9 March 1975
CIO March 1975
Oct. 1973
C5 Oct. 1973
Oct. 1973
C7 Oct. 1973
Oct. 1973
March 1975
July 1975
Description
Surface water from Trout Creek above
all mining activity and above Apex
Mine
Surface water from Trout Creek
above Edna Mine and Little Trout
Creek, but below Apex Mine
Surface water from Little Trout Creek
above Edna Mine
Mine drainage from older spoils
Intermittent stream flowing through
older spoils
Mine drainage in newer spoils
Surface water from Trout Creek below
older spoils
Mine drainage from newer spoils
Surface water from Trout Creek below
newer spoils
Subsurface water entering Trout Creek
below newer spoils
Surface water from Trout Creek below
newer spoils
Surface water on Trout Creek 1.6 km
north of oil mining activity
Surface water on Trout Creek approxi-
mately 8 km north of all mining
activity
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2. Station C13 reflects the influence of Little Trout Creek on Trout
Creek. Since the former has much lower flow levels, it has little
impact on the WQP's observed at C2 and below.
3. Site C3 is water which seeps from a pond within the oldest area of
the mine. Since it accumulates groundwater flowing through this
area, it reflects the WQP equilibria characteristic of the most
weathered spoils.
4. C5, a similar pond in the spoils of the area mined during the
1950's, reflects the aquatic equilibria characteristic of the
middle era spoils.
5. A subsurface water seep at the northern extreme is site C7; it
reflects the WQP impacts for the most recent spoils.
6. Stations C9 and CIO are located on intermittent streams originating
above and flowing through the mined area. These also reflect the
impact of spoils on the WQP's. In terms of spoils exposure, C9
compares with C3 while CIO compares with C5.
7. Stream stations C4, C6, and C8 were selected to reflect the fol-
lowing. Site C4 receives input from the C3, C9, and CIO watersheds
(Figure 5) and is therefore expected to reflect the impacts of the
older mine operations on the WQP's. The C5 watershed impacts on
sites C6 and C8.
8. The total impact of the mine operation can be estimated by compari-
son of WQP data at C8 with that at C2.
9. The effects of agricultural activities can be deduced by comparing
WQP data at C14 with those for C8 or Cll.
These delineations are taken into account 1n the evaluations summarized in
succeeding sections.
14
-------
(C14 = 8 km downstream)
Surface
C8
Ground C7
C6
Surface
C5 Pool
C4 Surface
CIO Pool
(underground)
Apex
Cl
Surfac
Figure 5. Location map of water quality monitoring stations
and mine surface watersheds in the study area.
(See Table 2 for more complete description.)
15
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SECTION V
METHODS AND PROCEDURES
Water samples were collected at each sampling station on a monthly
basis. These were preserved according to the recommended procedures des-
cribed by the U.S. Environmental Protection Agency (1974) manual on water
analysis and analyzed by the standard procedures given therein. The data
obtained were keypunched and placed on permanent tape file in the university
computer system for convenient summary and evaluation via any of several
available procedures. The data are available in a compilation report
(Skogerboe et at. 1978).
An analytical quality assurance program was maintained throughout the
term of this project. This included (1) submission of the same samples to the
analytical lab under different numerical designations to obtain precision
estimates, (2) running reference water samples from the USGS (using a desig-
nation system which disguised the fact that they were reference samples) to
obtain accuracy estimates, and (3) cross checking analyses by using spike-
recovery methods. Approximately 3-4% of all samples analyzed were actually
check samples of the above types. The overall conclusion drawn from these
quality assurance checks was that the analyses are typically accurate to ±10%
of the stated value; certain types of measurements, e.g., pH and specific
conductivity, were found to be accurate to better than ±5%.
16
-------
SECTION VI
RESULTS AND DISCUSSION
STREAM DISCHARGE PATTERNS
A plot of typical stream discharge results, obtained from McWhorter
et al. (1975), is given in Figure 6. In general, flow increased sharply in
April/May due to snowmelt, peaked in mid-June, and decreased sharply to its
low flow level by mid-July. Maximum flow (mid-June) did not coincide with
maximum snowmelt at the mine. The typically 3- to 6-week time lag between
these two events reflects the fact that stream flow is influenced, by the
later snowmelt at the higher elevations on Trout Creek. The influence of
this delayed snowmelt flow from higher elevations not associated with mining
is one of diluting the overall impact of the higher level of groundwater flow
from the mine during this period (see discussion below). The flow pattern
shown in Figure 6 varies in magnitude and in time from year to year depending
on snowfall and the temperature regime; the trends of the pattern are
qualitatively similar each year.
Most of the surface and subsurface inflow from the mine occurs 1n the
distance between stations C2 and C6. Therefore, the differences in discharge
at these two sites are indicative of the extent of such mine-associated
inflow for any month. Data of this nature indicate that the total flow
increases by 20-100% between these two stations depending on the seasoned
runoff conditions. These flow increases due to inflow from the mine are
usually accompanied by overall decreases in water quality. It is difficult
to generalize but examination of flow and dissolved solids data suggests that
a flow increase of X% between C2 and C6 is usually accompanied by an increase
in dissolved solids In excess of 2X%. Impacts of this nature, due to the
mine operation, are discussed further below.
WATER QUALITY DIFFERENCES WITHIN THE MINE
As previously noted, sites C3, C5, and C7 involve seepage (subsurface)
water within various mine watersheds which should reflect differences in the
age (weathering) of the spoils. The specific conductivity (SC) reflects
gross differences in waters associated with the respective sites. The plot
of SC versus time at each site (Figure 7) indicates temporal parallels but
distinct and consistent differences in the total dissolved solids concentra-
tions. Of primary interest is that increasing dissolved solids concentra-
tions are associated with progressively more recent mine spoils. Further
insight Into this may be obtained via examination of the water quality data
at each site (averaged over the time period of Figure 7) given in Table 3.
17
-------
^ 6-
o
V
in
-C
u
M
April May June July Aug Sep
Year (1975)
Nov Dec
Figure 6. Typical stream discharge data at Trout Creek.
(C2 - discharge at on-stream site above mine;
C6 = discharge at on-stream site adjacent to
mine; C6-C2 = Increase in discharge between
sites C2 and C6.)
18
-------
CO
O
O)
O
c
10
u
3
T3
£
O
CJ
u
O
CL
co
10,000 -
8,000 -
6,000-
4,000-
2,000-
Feb Apr Jun Aug Oct Dec Feb Apr Jun Aug Oct Dec Feb Apr Jun Aug Oct Dec
1974 1975 1976
Figure 7. Specific conductivity of surface waters at sites associated with various stages
of spoil weathering (C3 spoils approximately 30-40 years old; C5 spoils
approximately 15-25 years old; C7 spoils 1-10 years old).
-------
TABLE 3. AVERAGE VALUES OF WATER QUALITY PARAMETERS ASSOCIATED WITH SUBSURFACE WATERS FROM MINE SPOILS OF VARIOUS AGES
Average level of indicated water quality parameter-'
Sample site and Specific Dissolved
description conductivity solids Hardness Alkalinity Ca Mg SO,, Na 1C Cl
C-3; seepage from
area which has
... weathered 30-40
| years 2500 ± 700 2100 + 260 1700 ± 600 94 ± 40 370 ± 80 140 ± 40 1300 ±400 20 ± 4 4 ± 1 13 ± 4
fo 1
O Q. c-5; seepage from
<" area mi nee! in the
g1"? 1950's to 1960's 3600 ± 1000 3300 ± 460 2400 ± 800 170 ± 40 350 ± 80 270 ± 100 1800 ± 700 110 ± 40 16 ± 7 4 ± 1
li'Z
«j£ C-7; seepage from
h % area mined in the
= £ 1970' s 4800 ± 1300 4000 ± 500 2000 ± 500 380 ± 70 320 ± 100 190 ± 70 1300 ± 900 480 + 120 14 ± 6 8 ± 1
concentrations in mg/liter except specific conductivity (SC) given in vmhos.; ± values are standard deviations of the averages.
-------
Clearly, the dissolved solids levels increase with decreasing age of the
spoils and the same trend is evidenced for alkalinity (HC03~) and sodium.
The trend is nearly the opposite for Ca, Mg, and sulfate. This qualitatively
suggests the predominant Influx of soluble sodium salts (e.g., NaHC03 and
Na2C03) during the early years of water action on the spoils. Ultimately,
the more soluble materials of this nature are depleted and the dissolution of
less soluble materials (e.g., CaS04 and MgSOj becomes predominant. Thus,
the exact nature of the impact(s) of such mine effluent waters on surface
water quality will ultimately depend on the degree of previous weathering
exposure of the spoils, their general mineralogical makeup, and the hydro-
logic features of the mine area. McWhorter et al. (1975) have approximated
that the groundwater associated with the Edna Mine will maintain low quality
(comparable to that indicated in Table 3) for 500-600 years. There are
sufficient amounts of soluble materials in the disrupted areas exposed to
water to supply high levels of Ca, Mg, and SOi, (in particular) over this
extended time period.
STREAM WATER QUALITY; GROSS PARAMETERS AND COMMON ION IMPACTS
An overview of WQP changes on spatial as well as temporal bases may be
obtained from the specific conductivity data summarized in Figure 8. These
data emphasize that the total dissolved solids level at the C2 station above
all mining activity was relatively constant. The data for C6, however,
emphasize the high dissolved solids influx which occurs during periods of
snowmelt at the mine. Moreover, when the primary influx of water is from the
higher elevations above the mining activity, this results in rapid dilution
of dissolved materials that may be influent along the reaches of the mine.
Examination of flow data between C2 and C6 during the snowmelt of 1975, for
example, indicates a 15-25% increase in flow primarily due to surface and
subsurface runoff from the mine. This was accompanied, however, by a more
than 500% increase in the dissolved solids levels in the stream. Similar
observations may be noted for other snowmelt and precipitation periods; these
indicate that the mine operation is responsible for significant inputs of
dissolved solids.
Further examination of Figure 8 indicates groupings of time periods over
which the water flow and water quality characteristics are relatively con-
stant. Consequently, to summarize, the data into more tractable units, the
following seasonal groupings have been defined.
1. July to September is a period when surface runoff contributions are
minimal, the rate of evapotranspiration is high, and irrigation
return flow will be operative.
2. October to December is a period during which there is no irrigation
return flow, natural precipitation and snowmelt are low, and the
rate of evapotranspiration is minimal. Thus, comparison of these
two time periods provides approximations of subsurface contributions
in the presence and absence of irrigation return flow.
21
-------
"
lOOO-i
800-
£ 600
4->
O
ro
ro
o
c,
o
O
O>
Q.
to
400-
200-
I
Feb Apr Jun Aug Oct Dec Feb Apr Jun Aug Oct Dec Feb Apr Jun Aug Oct Dec
1974 1975 1976
Figure 8. Specific conductivity of surface waters above (C2) and adjacent to the
mine (C6).
-------
3. The January to March interval 1s a reference period during which
snowfall and surface, as well as subsurface, contributions should
be minimal.
4. April and May coincide in general with maximum snowmelt at the mine
elevation and the primary input of dissolved solids.
5. June is segregated due to the high runoff from higher elevations
and the concomitant dilution effects discussed above.
The average concentrations of the gross (common) water quality parameters for
each of these time blocks have been determined for each sampling station on
the stream. These data are presented in the three dimensional plots of
Figures 9 through 16. Complete data are published in a summary compilation
report (Skogerboe et al. 1978). These data can be obtained for the cost of
reproduction.
Examination of the dissolved solids data in Figure 9 emphasizes the
following distinguishing features.
1. The observed levels at all sites are highest during the April/May
snowmelt and lowest during the June snowmelt at higher elevations.
2. The dissolved solids concentration consistently increases in a
downstream direction reaching a maximum at approximately the lowest
reach of the mine (C8). The general dropoff further downstream is
probably due to dilution via other input sources and/or removal of
dissolved solids via various processes (e.g., precipitation).
3. The general occurrence of a maximum in the C4 to C6 region with a
slight drop thereafter implies (but not conclusively) that the
largest dissolved input is associated with the older areas of the
mine. Since these areas of the mine have not been regraded to
their original contours, infiltration into the spoils is encour-
aged. Inflow from these areas may consequently be greater.
4. Since all surface drainages from the mined area to the stream occur
above Cll, the small increase generally occurring between Cll and
C14 my reflect the effects of irrigation return flow between the
two sites.
Examination of similar data plots for hardness, Ca, Mg, SOi,, Na, K, and
Cl in Figures 10 through 16, respectively, emphasizes the recurrence of the
pattern and associated conclusions discussed above. A further emphasis of
the constant nature of this pattern may be obtained by examination of maximum
and minimum concentration data for the above parameters in relation to site
and season. The lowest concentration of any WQP is consistently observed at
sites Cl and C2 above the mine; these reach a minimum value during the high
elevation snowmelt of June. The highest WQP concentrations are consistently
observed In the April/May snowmelt at the mine and the maximum concentrations
usually occur 1n the stream section immediately adjacent to the mine between
C4 and C8.
23
-------
500 -,
CO
o
o
CO
Q)
r
O
to
(/I
5 10° -1
April/May
Jan.-Mar.
Oct.-Dec.
July-Sept.
June
Site
Designation
Figure 9. Spatial and temporal distribution of dissolved,sol ids,
24
-------
400n
CO
O
o
-------
200-1
June
Site
Designation
Figure 11. Spatial and temporal distribution of calcium
concentrations.
26
-------
40-
20-
Ol
10
April/May-1
Jan.-Mar.
Oct.-Dec.
July-Sept
fceA°*
^<\e
June
,xvt
Site
Designation
Figure 12. Spatial and temporal distribution of magnesium
concentrations.
27
-------
300-^
200-
^ 100-
April/May
Jan.-Mar.
Oct.-Dec.
July-Sept.
June
Site
Designation
Figure 13. Spatial and temporal distribution of sulfate concentrations.
28
-------
50-
Site
Designation
Figure 14. Spatial and temporal...dtstnHwtlon of sodium
concentrations.
29
-------
3.0
April/
Jan.-Mar.1
Oct.-Dec
Ouly-
Site
Designation
Figure 15. Spatial and temporal distribution of potassium
concentrations.
30
-------
3.00-1
H 2.00
i-
o
April/May
site
Designation
Figure 16. Spatial and temporal distribution of chloride concentrations,
31
-------
These results indicate that the mine operation has a direct impact on
the general water quality characteristics of Trout Creek. The principal
increase in total dissolved solids is due to delivery of soluble materials
from the mine.
Leaching of more recently disrupted strata results in contributions for
which dissolution of alkali metal carbonates, bicarbonates, and sulfates
(notably sodium) appear to be predominant. Ultimately the available supply
of these more soluble materials becomes sufficiently depleted so that the
dissolution of less soluble alkaline earth compounds becomes predominant.
Overall, the most predominant cations are Ca and Mg; Na and K are of secon-
dary significance in terms of relative concentrations. The principal anions
are bicarbonate/carbonate, sulfate, and chloride in approximately that order
of concentration predominance. The waters associated with the mine as well
as the stream above the mine are consistently basic; the carbonate/bicarbonate
equilibria serve to buffer the pH reasonably we!1. Thus, although it has
been shown by Temple and Kimble (1976) that pyrite minerals are often present
with the appropriate microbial populations for pyrite dissolution and the
concomitant acid production, there is adequate buffer capacity to neutralize
the quantities of acid produced. These factors also influence the equilibria
involving the heavy metals as discussed below.
HEAVY METAL IMPACTS
The concentrations of the heavy metals determined have also been sum-
marized (Skogerboe et dl. 1978). At all sampling sites the concentrations of
Al, Cr, and Pb were consistently below the detection limit of 5-10 yg/liter.
Since these elements were not detectable at a concentration factor of 10
below the aquatic life standards (see Table 4), the only conclusion to be
drawn is that their impact from the mine (if any) is not particularly
significant.
Data for the other elements are summarized graphically in Figure 17
where comparisons are drawn between the station above the mine (C2) and that
just below the mine (C8). The bars in Figure 17 indicate the range of con-
centrations observed for each element over the 2-year monitoring program.
The lower end of the bar indicates the detection limit for each element while
the upper end represents the maximum concentrations observed. The data were
also used to compute the average concentration at each site. However, in
most cases a significant percentage of samples had concentrations below the
detection limits. When this was the case, the detection limit was taken as
the estimate of the actual concentration present even though it was lower.
As a result, the averages determined are actually upper limit estimates of
the actual values; these averages are indicated by the - - symbol on each
bar graph. The percentage value given at the top of each bar indicates the
percentage of samples for which the element concentration was above the
indicated detection limit. It should be emphasized that an average deter-
mined on the basis of detectable concentrations in only 30% of the samples
(for example) will consequently be a greater overestimation of the actual
value than one determined from concentrations determined in a progressively
32
-------
TABLE 4. EQUILIBRIA AND EQUILIBRIUM CONSTANTS CONSIDERED
IN MODEL CALCULATIONS (SILLEN AND MARTELL 1964)
Species
H20
H2C03(a)
H2SO,
H3PO,
Al(III)
Cd(II)
Product(s)
H+ + OH"
H+ + HC03"
H+ + C032-
CaHC03+
CaCOgQ^
H+ + SO,2'
CaSO^o
H+ + \\2PQ^~
H+ + HP042-
H+ + P0,3-
A1(OH)3
A1P04
A10H2+
A1(OH)2+
AHOH),"
A1S04+
A1(SO^)2-
CdC03
CcKOHh.stSOJo^s
1/3 Cd3(POt|)2
CdSO,
Cd(OH)2
CdOH+
log K
-14
-6.35
-10.34
1.26
3.2
-1.99
2.31
-2.16
-7.21
-12.33
-32.5
-18.24
9.76
19.4
28.3
3.2
5.1
-13.74
-12.5
-10.72
-7.8
-14.5
6.08
33
-------
TABLE 4. CONTINUED
Species
Cd(II) (cont.)
Cu(II)
Hg2(ll)
Product(s)
Cd(OH)2°
Cd(OH)"
Cd(OH)£t2-
CdSO^0
CdCl*
CdCl2°
CdCl3"
CdCV'
Cu(OH)2
CuC03
1/3 Cu3(POit)2
CuOH+
Cu(OH)2°
CU(OH)3-
Cu(OHK2-
1/2 Cu2(OH)22+
CuC03°
Cu(C03)22'
CuC03OH"
CuSOi^0
CuCl*
Hg2C03
Hg,HPOu
log K
8.7
8.38
8.42
2.3
1.95
2.5
2.35
1.65
-19.7
-9.63
-12.3
6.66
14.32
15.5
13.8
5.26
6.34
10.01
15.0
2.35
0.95
-16.05
-12.4
34
-------
TABLE 4. CONTINUED
Species
Hg2(II) (cont.)
Hg(II)
Mn(II)
Pb(II)
Product(s)
Hg2Cl2
Hg2SOk
Hg2SO,o
Hg2(soJ22-
Hg(OH)2
HgOH+
Hg(OH)2°
Hg(OH)3~
Hg(OHK2'
HgS04°
Hg(SOj22-
HgCl+
HgC12°
HgCl3~
HgCllt2-
Mn(OH)2
MnC03
MnOH+
Mn(OH)3~
MnHC03"
MnSO,,0
Pb(OH)2
PbC03
log K
-17.88
-6.17
1.3
2.4
-25.4
10.2
22.66
21.8
21.3
1.34
2.44
6.74
13.22
13.79
15.25
-12.8
-9.3
3.41
1.8
1.8
2.26
-18.7
-13.4
35
-------
TABLE 4. CONTINUED
Species Product(s)
Pb(II) (cont.) 1/3 Pb3(POj2
PbHPO^
PbCl2
PbSO^
PbOH*
Pb(OH)2°
Pb(OH)3"
Pb2OH3+
Pb^(OH)^*
PbCl*
PbCl2°
PbCl3"
PbCV'
PbS04°
Zn(II) Zn(OH)2
ZnC03
1/3 Zn3(PO,t)2
ZnOH+
Zn(OH)3"
Zn(OH)42-
ZnSO^
ZnCl+
log K
-14.03
-9.9
-4.76
-7.8
6.22
10.34
13.95
6.7
35.7
1.6
1.78
1.68
1.38
2.46
-15.7
-10.8
-10.68
5.04
14.2
15.0
2.26
0.43
36
-------
TABLE 4. CONTINUED
Species
Zn(II) (cont.)
Fe(II)
Fe(III)
Product(s)
ZnCl2°
ZnCl3"
ZnCV'
Fe(OH)2
FeC03
FeOH+
Fe(OH)3-
Fe(OH)If2-
Fe(OH)3
FePO,,
fe(QH)H2PQk
FeOH2+
Fe(OH)2*
Fe2(OH)2
FeSOt/
FeCl2+
Fe(SOit)2-
log K
0.61
0.53
0.2
-15.1
-10.6
5.7
10.0
9.6
-38.6
-30.02
-34.56
11.81
20.84
24.54
4.10
1.48
5.44
-'Superscript ° indicates the compound in soluble form.
37
-------
1.0-
0.6-
I 0.2H
Se
60?,
76'.
Ct-
C2 C8
Total
Zn Fe
50-
10-
59i
-.-
38X
...
.1000-
600-
200-
ionr
...
IBM
...
-1000-
600-
-200-
C2 C8
C2 C8
Dissolved
Fe
6«
65*
-fr-
C2 CB
120-
30-
40-
Mn
36"
79?.
C8
- 90-
- 60-
30-
Cu
29%
-A--
?5J1
-*-
1.2-
Hg
C2 Ctl C2 CO
Station Number
As
474
*-
43«
- .4 -
- .3 .
70S 4«
_ ._
-ft-
C? CO
Figure 17. Elemental detection limits, observed concentration ranges,
frequency of occurrence above detection limits, and
average concentrations in surface waters above and below
the Edna Mine. Lower limits of bars indicate detection
limit; upper limits of bars indicate maximum observed
concentration; Vindicates average concentration observed;
and percentage number indicates frequency of occurrence
above detection limit.
38
-------
larger percentage of the samples. Nevertheless, the data can be used to draw
the following inferences. A similar data summary for the subsurface water
sampling sites within the mine is given in Figure 18. This also aids in the
following evaluation.
Manganese
The estimated average concentration of Mn in the stream after inflow
from the mine is approximately 65% higher than that above the mine. The
fact, however, that Mn was detected above the mine in only 36% of the samples
while 79% of those below had measurable concentrations tends to reduce the
actual magnitude of difference. It is probable that a more reliable estimate
of the differences could be based on multiplication of the average in each
case by the frequency of observation. Thus, for Mn, the weighted averages
would be 0.36(21) = 7.6 pg/liter at C2 and 0.79(31) = 24 yg/liter at C8.
Using these weighted values results in an indication that the Mn concentra-
tion increases by more than 200% between C2 and C8. Although a weighting
evaluation of this type can be supported on a statistical basis, it must be
considered qualitative or semiquantitative at best. The fact remains,
however, that Mn concentrations increase between the stations above and below
the mine. Moreover, examination of the data in Figure 18 (Skogerboe et al.
1978) indicates that the major influx is associated with the older section of
the mine (C3). This may be due to the greater Infiltration of water Into
these spoils or to the fact that these spoils have been weathered to the
extent that the controlling equilibria are shifting. The Mn concentration 1n
groundwater in the mine at C3 exceeds the permissible level (see Table 5) of
100 ng/Hter for 57% of the sample collections; this level was never exceeded
in those collections made at C8 on the stream below the mine.
Copper
This element was measurable in 25-30% of all stream samples (Figure 17).
Evaluation of the data generally suggests that Inflow from the mine 1s not
significant or minimal. Again 1t may be noted that the highest groundwater
levels are associated with the older mine areas (C3, Figure 18).
Mercury
The detection of mercury 1n a fairly high percentage of the subsurface
drainage samples 1n the mine (Figure 18) Indicates the presence of mercury
compounds or minerals that can be dissolved. The stream water analyses
(Figure 17) Imply the Inflow of a small amount of mercury from the mine, but,
on the average, this 1s not a particularly large contribution. The primary
mercury Inflow 1s associated with the snowmelt flushing period at the mine.
Although samples have been analyzed for the presence of organo-mercury
compounds, none have been detected.
39
-------
C3
Se
Zn
As
23-
12-
8-
"fc
£ 4-
1
g
0
,
sor
[-fr J
1 100", I
_
_
100%
-ir-
, 100-
60-
- 20-
591
^-
57t
Ld
.0.5-
- 0.3"
0.1-
567. 201;
-* -*-
C5
Mn
600-
zon- -
C7
977,
-tt-
5")*
7 U
C3 C5 C7
C3 C5 C7
Cu
C3 C5 C7
90
60
30-
29X Ri! 8!
-A-
*&-
L*-
53-;
-6-
C3 C5 C7
Station Number
C3
Hq
60J
-ir-
C5
C7
Figure 18. Elemental detection limits, observed concentration
ranges, frequency of occurrence above detection
limits, and average concentrations of subsurface
waters in the Edna Mine. Lower limits of bars
indicate detection limit; upper limits of bars
indicate maximum observed concentration; ft indicates
average concentration observed; and percentage number
indicates frequency of occurrence above detection
limit.
40
-------
TABLE 5. QUALITY CRITERIA FOR HATER (U.S. ENVIRONMENTAL
PROTECTION AGENCY. 1976}
Parameter
Alkalinity
Arsenic
Cadmium
Chlorine
Chromium
Copper
Hardness
Iron
Lead
Manganese
Mercury
Nickel
Dissolved oxygen
PH
Selenium
Silver
Aquatic life
20 ing/Hter (or more as CaC03)
100 ug/11ter
0.4 ug/Hter (soft water)5/
1.2 pg/llter (hard water)
20 ug/11ter
100 ug/11ter
0.1 x « 96-h LC50^ (LDSO 48-60 ppb)5/
Related to what contributes to the
hardness
1.0 mg/llter
0.01 x a 96-h LCSO (LDSO 48-450 ppb)
100 vg/Hter
0.05 ug/llter
0.01 » a 96-h LCSO (LD50 48-1.12 ppm)
5.0 mg/llter minimum
6.5 to 9.0
0.01 x a 96-h LC50
0.01 x a 96-h LCSQ
Drinking
water
50 pg/llter
10 pg/Hter
50 pg/Hter
1.0 mg/llter
0.3 mg/Hter
50 ug/llter
50 vg/11ter
2.0 ug/Hter
5.0 - 9.0
10 yg/Hter
50 ug/11ter
-'
£/
water: 0-75 mg/Hter CaC03; hard water: 150-300 mg/llter CaC03
Is defined as the concentration of a toxicant which Is lethal to
50% of the organisms tested under the test conditions 1n a specified
time. (The receiving or comparable water should be used as the
diluent for sensitive freshwater resident species.)
LD50 1s defined as the dose of a toxicant that Is lethal to 50% of the
organisms tested under the test conditions In a specified time. A dose
Is the quantity actually administered to the organism and 1s not
Identical with a concentration, which Is the amount of toxicant In a
unit of test medium rather than the amount Ingested by or administered
to the organism [example L050 48 (number of hours) - 60 ppb].
41
-------
Selenium
The data for selenium are more striking. At the off-stream sites
draining the 1950 and 1960-1970 age spoils (C5 and C7, Figure 18), the
observed levels are quite high and exceed those observed at the on-stream
sites (Figure 17) by factors of 5 to 10. Station C5 receives water passing
through an unfilled box cut in the mine. The Se level here is particularly
high; the permissible level (Turbak et at. 1976) of 10 yg/liter was exceeded
in 60% of the samples analyzed. Relatively large amounts of Se are also
being leached from the newer area of the mine (C7). Clearly, larger amounts
of Se are being leached from the spoils than from undisturbed strata. The
distinguishing features of the C5 and C7 watersheds which account for this
have not been identified. Inflow from these areas accounts for the approx-
imately 30% to 40% average increase in the Se concentration in Trout Creek
between the up- and downstream sampling sites. Again, the primary impact is
observed in the spring runoff period. Checks have failed to indicate the
presence of organo-selenium for these monitoring stations.
Zinc
Again, the occurrence of higher zinc concentrations in groundwater is
most prominently associated with older areas of the mine (Figure 18).
Consideration of the summary in Figure 17, however, indicates that the fre-
quency of occurrence of measurable zinc is less downstream of the mine, i.e.,
the weighted average zinc concentration decreases. This implies that other
constituents delivered to the stream from the mine suppress the concentra-
tions of soluble zinc, e.g., by precipitation. This possibility is discussed
in more depth in a section dealing with chemical equilibria below.
Arsenic
The data for this element do not parallel those for selenium. The
amounts of As associated with groundwaters are relatively constant regardless
of the degree of weathering of the spoils (Figure 18). Moreover, the stream
data (Figure 17) again imply that other chemical contaminants from the mine
may reduce the amount of soluble arsenic in the stream via some removal
mechanism. It has been established that more than 95% of the As determined
is inorganic; no organo-arsenic has been detected.
Iron
This element was detectable in all samples collected. Its average level
in the oldest mine area (C3) was 450 yg/liter, dropping to 200 yg/Hter 1n
the C5 watershed, and rising to 1600 yg/liter in the newest area of the mine
(C7). Thus, recently exposed strata contribute more iron to the groundwater
than those which have undergone weathering. The average concentration 1n the
stream remained constant, between the above- and below-mine sites, at -400
yg/liter. Thus, although this exceeds the permissible drinking water
42
-------
recommendation of 300 pg/liter, the data do not indicate input of a signifi-
cant amount of iron from the mine. Again, it should be emphasized that iron
minerals, including pyrite, are present but the prevalent chemical equilibria
control the dissolved iron concentrations as well as neutralize any add
production due to pyrite dissolution.
SUMMARY
The heavy metal results discussed above and summarized in Skogerboe
et al. (1978) indicate the following.
1. The mine operation has no detectable impact on Trout Creek in terms
of increasing the concentrations of Al, As, Cd, Cr, Cu, Fe, Pb, or
Zn.
2. Significant increases in the stream concentrations of Mn and Se due
to the mine inflow can be inferred from the data. Although these
increases occur, their magnitudes are such that significance in
terms of potential impacts on aquatic biota does not appear likely.
Exception to this may occur in the mine pond at station C5.
3. In terms of the groundwater impacts, higher concentrations of the
elements Mn and Zn are associated with subsurface waters in equi-
librium with the oldest spoils. The reverse appears true for Cu,
Cr, and Cd but the data are much more limited. Higher levels of
As, Fe, and Se are associated with groundwater in equilibrium with
the less weathered spoils.
4. These general observations emphasize that the potential impacts on
the surface and subsurface water quality depend on several factors
including: the degree of infiltration as influenced by the mine
contours and precipitation, the physical and mlneralogical charac-
teristics of the disrupted strata, the flushing (contact) time
associated with the Individual watersheds, the extent of spoils
weathering, the oxygen availability, and the chemical equilibria
operative. All these factors must be considered 1n predicting
impacts, 1n evaluating the mechanistic parameters which may control
these impacts, and in making recommendations for control strategies
where appropriate.
43
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SECTION VII
EVALUATION OF CHEMICAL EQUILIBRIA
As previously indicated, the primary contaminants entering Trout Creek
from mine inflow are the gross water quality constituents: alkalinity and
soluble salts. McWhorter &t al. (1975) have discussed the impacts associated
with these and have formulated a model offering a predictive capability.
Their results are consequently not repeated here; a complete discussion is
contained in their publication (McWhorter et al, 1975).
It has been noted above that concentrations of most heavy metals are
generally in the low ug/liter range; 1t appears that these levels (except for
As, Cd, and Hg) would not normally be considered acutely toxic to aquatic
organisms. This observation is generally contrary to what has often been
reported for coal development areas in the Appalachian region. Moreover, it
has been noted that some heavy metals associated with energy development
sites in the West occur in mineral forms normally considered soluble. Thus,
it is appropriate to consider what factors may account for the low concentra-
tions generally observed.
Fairly comprehensive water quality data sets have been accumulated for
the study site described above. The data on this and other western streams
are augmented by data from the respective state water resources agencies,
USGS, and EPA. Examination of these data, as well as those for other streams
in the western energy development area, indicates that their general water
quality characteristics are quite similar on a broad scale. Based on this
examination, the following generalizations can be made concerning on-stream
sites at Trout Creek and numerous other western streams:
1. The observed pH values range from 6.5 to 9.5 with 93% of all values
falling in the range between 7.0 and 8.5.
2. Total alkalinity ranges from 20 to 200 mg/liter (as calcium car-
bonate) with 85% of all values ranging between 60 and 180 mg/liter.
Acidity is usually less than 1 mg/liter.
3. Total hardness ranges from 40 to 670 mg/liter as calcium carbonate,
with 84% of all values falling below 250 mg/liter.
4. Total sulfate covers the 1 to 500 mg/liter range with values less
than 100 mg/liter being most common.
5. Chloride concentrations rarely exceed 1 mg/liter.
44
-------
6. Nitrate concentrations rarely exceed 1 mg/Hter.
7. Orthophosphate levels are typically less than 0.1 mg/Hter.
These parameters may be generally considered primary 1n controlling the
chemical equilibria which determine the solubilities of many heavy metals.
In view of the mineralogical and/or chemical characteristics of the
soils, sediments, and mine overburden/spoils of this region, the general con-
centration levels of the anionic species cited above should be essentially
"fixed" in the ranges mentioned above. Moreover, the morphologies of most
western streams are such that their waters will remain in reasonable equi-
librium with atmospheric constituents such as C02 and 02 as Influenced by
other parameters such as pH, temperature, alkalinity, etc. Simply stated,
the observed ranges of pH, carbonate, alkalinity, sulfate, etc., can be
defined as generally representative of the entire western coal development
region. These ranges can consequently be taken as boundary conditions 1n
considering the heavy metal equilibria that should prevail in the dbeenoe of
unusual circumstances, e.g., the presence of appreciable concentrations of
organic ligands. The ranges above should, within limits, be relatively
unperturbed by the addition of other constituents such as metal Ions unless
such additions involve majov Influxes. Consequently, the equilibrium models
can be used for predicting the fates of heavy metals which may be available
in forms soluble under other conditions.
Equilibrium calculations can thus be used to estimate maximum solu-
bilities of several heavy metals under the conditions representative of the
chemical and mineralogical features of the soils and spoils and the ground-
water and surface water of the area; this assumes the absence of other
Interacting components such as organic Ugands. These calculations may be
made assuming that the heavy metals in question exist in soluble forms at
their origin, e.g., a strip coal mine. If they do not, the maximum solu-
bility calculations will be overestimates of the actual case. It can be
easily argued that such definitions of upper limits serve as valuable
reference points.
Two general types of chemical Interactions may occur for a particular
metal ion and any combination of the anionic species stipulated in the above
set of generalizations. Immobilization of the metal ion due to precipitation
or to ion exchange type processes may occur. Alternatively, the 1on may be
mobilized by complexation reactions which effectively enhance its solubility.
In either case, the interactions Involved can be described by thermodynamic
parameters. The relative significance levels of the possible equilibria can
therefore be assessed on the basis of thermodynamic stabilities. Reactions
resulting in the largest increases in stability will tend to be principal
among the various possibilities. The compilation of equilibrium constants
(Si 11 en and Martell 1964) has been used as the data source for the present
calculations.
The equilibria considered for each metal ion are listed in Table 4.
Precipitates of a complex nature [e.g., Zn(C03)o.36(OH)1.2a] were not
45
-------
considered since such precipitates are usually formed only slowly from simpler
precipitates (e.g., ZnC03) rather than directly in solution. They will,
therefore, not be the controlling equilibria on the time scale of importance
herein, i.e., a few days. Some other equilibria could also have been
included, but were rejected either because: (1) their equilibrium constants
were too low to be considered significant relative to those listed, or
(2) the concentrations of the anions involved indicated a lack of signifi-
cance. The equilibria in Table 4 have been written so the stoichiometric
coefficient of the aquated metal ion is unity. This practice has been
followed to simplify model calculations. The equilibrium constants used in
the calculations are also given in Table 4; values chosen were for 25°C and
zero ionic strength. In instances for which two or more independent deter-
minations of an equilibrium constant did not agree, average values were
selected for the present calculations. For metals having more than one
common oxidation state, all states were considered because the redox charac-
teristics of the waters may vary significantly. In all calculations, the pH
was selected as the independent (master) variable. The common ranges for
each of the anions present, as indicated above, were used to define the
boundary conditions for the calculations. Thus, the low and high ends of the
typical concentration range for each anion were used in the calculations to
define the extremes of the controlling equilibria possibilities. For anions
that could be present in various forms, the pH-based calculations were used
to determine the relative concentrations of each form. Carbonate, for exam-
ple, may be present as dissolved C02, H2C03, HC03", C032~, CaHCOs4", and
CaC03°. The species CaHC03+ and CaC03° are soluble complexes which, because
of the typically high levels of calcium in solution (>60 mg/liter) may tie up
a significant fraction of the total carbonate. The appropriate equilibrium
constants were consequently used in the calculation format outlined below to
determine the respective concentrations of each of the free carbonate species
at the pH level in question. The carbonate boundary condition concentrations,
given as a footnote to Table 6, are thus for the total of all carbonate-
related species. Similar adjustments were made for other anions as required.
Since the interest is in obtained estimates of the maximum concentration
of soluble metal, any effect which will tend to increase solubility should be
taken into account. The effect of ionic strength is such that solubilities
of metal salts will be increased at higher ionic strength; hence a correction
for ionic strength has been made; i.e., the equilibrium calculations are
carried out in terms of activities which are related to concentrations by the
relation:
a = yC
The activity coefficient y decreases with increasing ionic strength, where
ionic strength, I, is defined by
I h zC.z.2
46
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TABLE 6. COMPARISON OF CALCULATED AND OBSERVED MAXIMUM
CONCENTRATIONS AT STREAM AND MINE SPOIL DRAINAGE SITES
Stream concentrations
(yg/Hter)
Metal
Cd(II)
Hg(II)
Al(III)
Zn(II)
Cu(II)
Fe(III)
Mn(II)
Pb(II)
Calculated^/
maximum
3.1
360,000
23
1600
830
0.001
45,000
14
Observed
maximum
1.8
1.3
<500
170
41
1100
180
28
Mine spoil concentrations
(yg/liter)
Calculated^
maximum
2.4
360,000
26
1500
1400
0.001
43,000
14
Observed
maximum
10
1
<500
130
58
1200
1200
<5
-^Conditions:
Conditions;
0.01
pH = 7; alkalinity = 150 mg CaC03/liter;
S042- = 80 mg/liter; Cl" = 1 mg/llter; PO^3
mg/liter.
pH = 7; alkalinity = 370 mg CaC03/liter; SO,*- = 1500
mg/liter; CT = 2 mg/liter; PO.,3- = 0.01 mg/Hter.
47
-------
where zj is the charge of the ith ionic species and GJ is its molar concen-
tration. The activity coefficients have been calculated for the typical
concentration ranges cited above via the equation:
log Y+z - -A 22 _£- (1)
±z i + /r
where A is a constant whose value depends only on the solvent and temperature.
This equation is generally accepted as the best available for estimating the
values of 7 in an aqueous system containing more than one salt (i.e., a mixed
electrolyte system) (Stumm and Morgan 1970). Failure to include an ionic
strength correction lowers the calculated total metal solubilities by 5-10%
for typical stream conditions and by 5-30% for typical mine spoil drainage
conditions.
As indicated above, reactions between metal ions and anions may involve
precipitation or complexation. The general expression for precipitation of a
metal ion, Mn+, by an anion, A1"-, is:
and
Mn+ + n/m Am~ * 1/m jyi (2)
Ksp - (Mn+)(Am-)n/m (3)
where parentheses indicate the activities of the species. A similar expres-
sion for complexation would be:
(4)
and
(MA n-qmj
/c\
Considering the equilibria for Zn2+ as an example (Table 4) the following
expressions may be evaluated.
(Zn2+) = 10'15-7/(OH")2 (6)
(Zn2+) = 10'10-8/(C032-) (7)
(Zn2+) = 10'^-'+2/(C032-)0.36(OH-)i.28 (8)
48
-------
(Zn2+) = 10-10-68/(POif3-) (9)
and
(Zn2+) = 10-13-
Thus, for example, at pH = 7; (OH") = 10'7 M; (POU3-) = 10~5 M; and total
carbonate species (C03)T = 3 x io~3 M; it may be determined that the solu-
bility of Zn will be limited principally by carbonate precipitation (Equa-
tion 7) to a molarity of 10~5. This calculation has consequently defined the
controlling precipitate as well as the upper limit concentration of Zn2+.
The quantity of interest is the total soluble zinc which is the experimentally
determined quantity regardless of chemical form. Again referring to Table 4,
the total soluble Zn, (Zn)|, may be defined as the sum of all dissolved Zn-
containing species, i.e.,
(Zn)T = (Zn2+)/Y±2 + (ZnOH+)/Y+l + (Zn(OH)3')/Y±l
+ (Zn(OHK2-)/Y±2 + (ZnS04°) + (ZnCl + )/Y±l (11)
+ (ZnCl2°) + (ZnCl3")/Y±l +
The concentrations of each of these complexes may be expressed in terms of
the (Zn2+), the appropriate anion concentration, and the respective equi-
librium constants. Equation 11 may be reduced to:
(Zn)T = (Zn2+) 1/Y±2 + IQS-O^OH'J/Yil + 101I+-2(OH~)3/Y±1
+ 1015(OH~)VY±1 + 102-26(SOtt2-) + lOO-^CO/Yil (12)'
+ ... 10°'2(C1")VY±2
Evaluation of this for the pH = 7 conditions listed above when (Zn2+) = io~5-°
indicates that the total soluble Zn concentration when complexation reactions
are considered may be increased to 2.4 * 10'5 M. This coincides with a
concentration of -1.6 mg/liter. These same calculation procedures have been
carried out for the given sets of boundary conditions for the metals listed
in relation to pH.
The results have been summarized graphically as shown in Figures 19 and
20. In each case, the precipitating form of the element which controls its
*
Calculations based on this are very much upper limit estimates since it does
not take into account the possible competition between the complexing ligands
for binding of other metals present.
49
-------
1000*
10 4
; I3
10
CU(OH)-
10
Figure 19, Solubility of metals under typical natural water conditions.
Conditions representative of mine spoil drainages
(in mg/liter): [HC03-] = 450, [SO^2'] = 1500 '
[C1-] = 2, [PO^3-] = 0.01
------ Conditions representative of on-stream conditions
(in mg/liter): [HC03-] = 180, [SO,,2'] = 80,
[C1-] = 1, [PO,,3-] = 0.01
The precipitating forms of the element, which control the
solubilities over the indicated ranges, are given on the
figures.
50
-------
iooo H
10
10
10"
10'
10
MANGANESE
6 I
Figure 20. Solubility of metals under typical natural water conditions,
-Conditions representative of mine spoil drainages
(in mg/liter): [HC03-] = 450, [S042-] = 1500,
[CT] = 2, [P043-] = 0.01
Conditions representative of on-stream conditions
(in mg/liter): [HC03-] = 180, [SO^2'] = 80,
[CT] = 1, [POit3'] = 0.01
The precipitating forms of the element, which control the
solubilities over the indicated ranges, are given on the
figures.
-------
solubility has been indicated for the applicable pH range. Examination of
these results indicates that precipitation by carbonate or hydroxide are
typically the controlling equilibria in this pH range. It may also be noted
that the solubilities of most metals increase with pH at levels above -8-9
due primarily to the formation of soluble hydroxy complexes. The solubilities
also tend to increase in more acid solutions due to protonation of the car-
bonate. Of particular interest is that most metals examined are least
soluble in the commonly observed pH range of 7-8.
The calculated solubilities in this pH range for the elements in ques-
tion are given in Table 5 where they are compared with the maximum concentra-
tions that have been observed for the Trout Creek field sites described
previously. The reasonably good agreement between the calculated and mea-
sured values is indicative of the general validity of these equilibrium model
calculations. The discrepancy for Mn may be due to the formation of Mn02;
lack of necessary equilibrium constants precluded consideration of this
species in the equilibrium calculations.
These model calculations demonstrate that, in view of the typically
basic waters characteristic of the western energy development areas, the
soluble levels of many potentially toxic heavy metals will remain quite low
and should not ordinarily present a problem. Exceptions to this may occur
when the typical pH levels are shifted one or more units toward either the
acid or base side. To evaluate this, acid and base buffer capacities have
been calculated for Trout Creek and other western streams. Typical values
are summarized in Table 7. These are sufficiently high to indicate that
rather major influxes of acid or base would be required to cause a pH shift
adequate to change appreciably the metal solubilities involved.
The levels of arsenic and selenium have not been analyzed in detail
using these equilibrium models. For both elements, equilibria besides
precipitation and complexation are believed to play an important role in
determining observed levels (Hem 1970). In the case of selenium, the
observed levels are far above those expected if selenide (Se2~) is the
oxidation state present. The selenium is probably present as either selenite
(Se032~), or as selenate (Se042~). Checks have failed to indicate the
presence of organo-selenium or organo-arsenic compounds. Arsenic is almost
certainly present as arsenate, distributed primarily as H2AsO^~ and HAsO^2".
It appears that no arsenate solubility products are exceeded in this natural
water system.
Included in Table 8 is a list of the primary chemical forms in which the
various metals will be present under the limiting water conditions defined
above. These forms will be present regardless of whether or not the total
metal can be analytically determined. Most often only one or two complexes
account for most of the soluble metal and that these complexes are the aquo
or hydroxo forms. In this case, the pH directly determines the exact form
(aquated or hydrolyzed) of the major complex(es). For some metals (e.g.,
lead, manganese, and zinc) a sulfate complex may become important when
sulfate levels are in large excess (>100 yg/liter); this may occur in mine
spoil drainages (e.g., stations C3, C5, and C7).
52
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TABLE 7. SUMMARY OF ACID-BASE BUFFER CAPACITIES (SKOGERBOE ET AL. 1978)
CJI
CO
Acid buffering capacity
mmol /liter calculated
value
Average
Standard deviation
Percent (standard deviation x 100/ave.)
Number of measurements
Minimum value
Maximum value
4
0.51
0.26
51.82
15.0
0.19
1.12
Sites
6
0.58
0.48
82.06
15.0
0.18
1.90
8
0.51
0.33
64.71
35.0
0.11
2.08
Basic buffering capacities
mmol /liter calculated
value
4
0.17
0.05
29.05
15.0
0.11
0.31
Sites
6
0.23
0.13
56.20
15.0
0.10
0.50
8
0.17
0.08
47.52
35.0
0.07
0.52
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TABLE 8. PRIMARY CHEMICAL FORMS OF SOLUBLE METALS
PREDICTED BY THE EQUILIBRIUM COMPUTATIONS
Metal
Primary metal complexes in the
pH range 7-
Major forms
Secondary forms
Cu(II)
Fe(II)
Fe(III)
Hg(II)
Mn(II)
Pb(II)
Zn(II)
Cu(OH)2° (37-89)
CuC03° (26-7)
Cu(aq)2+ (25-0.6)
Fe(aq)2* (87-68)
Fe(OH)2+ (99-100)
Hg(OH)2° (100)
Mn(aq)2+ (87-86)
Pb(aq)2+ (79-41)
PbOH+ (10-53)
Zn(aq)2+ (92-86)
CuOH+ (8.8-2)
Cu(OH)3" (0.4-0.8)
CuHC03" (0.1-0.4)
Fe(OH)+ (3.5-26)
FeSO^0 (8-6)
FeOH2+ (1-0)
None
MnC03° (5.9-6.8)
MnSOi, (7.1-6.7)
Pb(OH)2° (0.01-0.6)
PbSO^ (10-4)
ZnOH"1" (0.79-7.3)
ZnSOi+o (7.4-6.7)
Bother conditions: alkalinity = 100 mg/liter (CaC03);
sulfate = 100 mg/liter; chloride = 10'1
mg/liter;
phosphate = 10"1 mg/liter; i = 0.006 M.
^Numbers in parentheses are the percents present in these forms in
the pH range 7-8.
54
-------
The equilibria for copper present a striking contrast to the other metal
ions because a large fraction is present as a carbonate complex. The form of
copper may also vary drastically, ranging from the aquo form under slightly
acidic conditions, to the carbonate forms in waters of high carbonate alka-
linity. No other metal examined shows so much variation in speciation
depending upon the exact conditions.
55
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REFERENCES
Bass, N. W., J. B. Eby, and M. R. Campbell. 1955. Geology and mineral fuels
of parts of Routt and Moffat Counties, Colorado. Survey Bull. 1027-D,
U.S. Geological Survey, p. 143-177.
Campbell, M. R. 1923. The twenty-mile park district of the Yampa coal
field, Routt County, Colorado. Survey Bull. 748, U.S. Geological
Survey, p. 4-8.
Canton, S. P., and J. V. Ward. 1978. Environmental effects of western coal
surface mining. Part II. The aquatic macroinvertebrates of Trout
Creek, Colorado. Ecol. Res. Ser. U.S. Environmental Protection Agency,
Duluth, Minnesota. (In press)
Goettl, J. P., Or., and J. W. Edde. 1979. Environmental effects of western
coal surface mining. Part I. The fishes of Trout Creek, Colorado.
Ecol. Res. Ser. U.S. Environmental Protection Agency, Duluth, Minnesota.
(In press)
Hem, J. D. 1970. Study and interpretation of the chemical characteristics
of natural water. Water-Supply Paper 1473, U.S. Geological Survey, p.
207-208.
McWhorter, D. B., R. K. Skogerboe, and G. V. Skogerboe. 1975. Water quality
control in mine spoils, Upper Colorado River Basin. Publ. No. 670,
Environmental Protection Techno!. Ser., U.S. Environmental Protection
Agency.
Sillen, L. G., and A. F. Martell. 1964. Stability constants of metal-ion
complexes. Spec. Publ. No. 17, Chemical Society, London.
Skogerboe, R. K., C. S. Lavallee, M. M. Miller, and D. L. Dick. 1978.
Effects of a surface coal mine on water quality: Trout Creek, Colorado.
Compilation of chemical data. NREL-FBL Tech. Rep. No. 1. Natural
Resource Ecology Laboratory, Colorado State Univ., Fort Collins, and
Fisheries Bioassay Laboratory, Montana State Univ., Bozeman.
Stumm, N., and J. J. Morgan. 1970. Aquatic chemistry. Wiley-Interscience,
New York.
56
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Temple, K. L., and F. Kimble. 1976. Quality of leach water from Montana
coal mine spoils, p. 375-400. In. R. V. Thurston, R. K. Skogerboe, and
R. C. Russo (ed.) Toxic effects on the aquatic biota from coal and oil
shale development: Progress ReportYear 1. NREL-FBL Internal Proj.
Rep. No. 9. Natural Resource Ecology Laboratory, Colorado State Univ.,
Fort Collins, and Fisheries Bioassay Laboratory, Montana State Univ.,
Bozeman.
Turbak, S., G. McFeters, and G. Olson. 1976. Effects of coal mining and
energy conversion on aquatic microflora, p. 413-448. .In. R. V. Thurston,
R. K. Skogerboe, and R. C. Russo (ed.) Toxic effects on the aquatic
biota from coal and oil shale development: Progress ReportYear 1.
NREL-FBL Internal Proj. Rep. No. 9. Natural Resource Ecology Laboratory,
Colorado State Univ., Fort Collins, and Fisheries Bioassay Laboratory,
Montana State Univ., Bozeman.
U.S. Environmental Protection Agency. 1974. Manual of methods for chemical
analysis of water and wastes. U.S. Environmental Protection Agency,
Washington, D.C.
U.S. Environmental Protection Agency. 1976. Quality criteria for water.
U.S. Environmental Protection Agency, Washington, D.C. 256 p.
57
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-79-008
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Environmental Effects of Western Coal Surface Mining
Part III - The Water Quality of Trout Creek, Colorado
5. REPORT DATE
January 1979 Issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR
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