oEPA
:>5804
/9
Environmental
Effects of Western
Coal Surface Mining
Part IV—Chemical and
Microbiological
Investigations of a
Surface Coal Mine
Settling Pond
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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
8. "Special" Reports
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 trie-public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/3-79-125
December 1979
ENVIRONMENTAL EFFECTS OF WESTERN COAL SURFACE MINING
PART IV - CHEMICAL AND MICROBIOLOGICAL INVESTIGATIONS
OF A SURFACE COAL MINE SETTLING POND
by
Susan C. Turbak, Gregory J. Olson, and Gordon A. McFeters
Department of Microbiology
Montana State University
Bozeman, Montana 59717
Grant No. R803950
Project Officer
Donald I. Mount
Environmental Research Laboratory-Duluth
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
This report is one of a series that characterizes the impact of
surface mining coal in the western U.S. In this study chemical-microbial
changes in the settling pond receiving mine runoff are described. Since
the form of compounds do change substantially as a result of physical
conditions and microbial activity, such information is useful in design of
such settling ponds.
Donald I. Mount, Ph.D.
Environmental Research Laboratory-Duluth
111
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ABSTRACT
Chemical and microbiological investigations of the settling pond system
at the West Decker Coal Mine in southeastern Montana were undertaken during
an 18-month period from November 1975 to April 1977. West Decker is one of
the largest surface coal mines in the United States. Extensive chemical
analysis of pond water samples during a portion of this period revealed that
coal mining in the Decker area may be impacting groundwater quality since
the pond water differed chemically from surrounding groundwaters. Concen-
trations of total dissolved solids, bicarbonate, sodium, sulfate, and nitro-
gen species in pond water were elevated in comparison to those in other
nearby surface waters; however, it was concluded that these would not sig-
nificantly impact the Tongue River or Tongue River Reservoir. Constituents
of the mine drainage waters underwent chemical changes within the pond which
were at least in part due to the activities of microorganisms. The increase
in pH value and in concentration of dissolved oxygen, partially attributed
to photosynthesis within the pond, oxidized reduced chemical species such as
sulfide and ferrous iron. The high numbers and activity measurements of
sulfate reducing bacteria as well as the significant amount of metal-bound
sulfides in pond sediments made a strong case for the contributions of these
organisms to metal precipitation in, and possible detoxification of, pond
waters. Acidophilic iron and sulfur bacteria, responsible for the produc-
tion of acid mine drainage, were consistently detected within the pond
system and other locations at Decker. However, no acidic conditions were
observed, most likely because relatively high concentrations of mineral
carbonate in the overburden neutralized acid formed from pyritic materials
present.
IV
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CONTENTS
Page
Foreword iii
Abstract iv
List of Figures vii
List of Tables viii
Acknowledgment x
I. INTRODUCTION 1
II. CONCLUSIONS 5
III. RECOMMENDATIONS 6
IV. DESCRIPTION OF THE STUDY AREA 7
V. MATERIALS AND METHODS • 10
Sample Collection 10
Measurement of Chemical Parameters 11
Algal Productivity 15
Productivity Estimates 15
Chlorophyll Measurements 15
Algal Bioassays 15
Bacteriology 16
Estimation of Selected Bacterial Populations 16
Enrichment of Selected Bacterial Populations 16
Purification, Tentative Identification, Growth and
Survival of Acidophilic Iron Oxidizing Bacteria ... 16
Leaching Experiments with Thipbacillus ferrooxidans . . 18
Physiological Studies of Thiobacillus ferrooxidans
using Respirometry 18
Sulfate Reduction in Pond Sediments 18
VI. RESULTS AND DISCUSSION 20
Chemical Parameters 20
Nutrients, Cations, Anions, and Other Parameters ... 20
Potentially Toxic Elements 29
Sediment Chemistry 31
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Page
Algal Productivity 31
Productivity Estimates 31
Chlorophyll Measurements 32
Algal Bioassays 33
Bacteriology 34
Estimation of Selected Bacterial Populations 34
Enrichment of Selected Bacterial Populations 39
Growth and Survival of Acidophilic Iron Oxidizing
Bacteria 40
Leaching Experiments with Thiobacillus ferrooxidans . . 42
Physiological Studies of Thiobacillus ferrooxidans
using Respirometry . 42
Sulfate Reduction in Pond Sediments 44
VII. SUMMARY 47
Conclusions 47
Recommendations 48
REFERENCES . 50
APPENDIX - WATER CHEMISTRY AND ALGAL PRODUCTIVITY DATA, WEST DECKER
MINE SETTLING POND, JULY 1976-April 1977 57
VI
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LIST OF FIGURES
Number Page
1. Map of Montana showing location of study area 3
2. Map of the Tongue River Reservoir showing the locations of the
present and future mines operated by Decker Coal Company 4
3. Map of the settling pond system at the West Decker Mine showing
sources of chemical input and output, and locations of sampling
sites 8
4. Description of the treatment of water samples obtained from
the West Decker Mine settling pond system prior to performing
chemical analyses 12
5. The biological sulfur cycle 36
6. Growth curve of two isolates tentatively identified as
Thiobacillus ferrooxidans, TF-1 and TF-2 41
VII
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LIST OF TABLES
Number Page
1. Monthly description of the settling pond system at the West
Decker Mine 9
2. Description of the methods used for the chemical analyses of
water samples from the settling pond system at the West Decker
Mine 13
3. Methods used for the detection and enumeration of selected
bacterial populations 17
4. Results of chemical analyses performed on samples from the West
Decker Mine settling pond 21
5. Selected chemical parameters measured on water samples collected
from influent and effluent waters of the settling pond system at
the West Decker Mine 25
6. Comparison of chemical parameters of groundwater samples obtained
from aquifers in the coal seams at Decker and the water of the
mine settling pond effluent 28
7. Levels of possible toxicants in waters of the West Decker Mine
settling pond system 30
8. Elemental analyses of sediment samples collected at the West
Decker Mine settling pond 32
9. Most probable number estimations of organisms potentially
functional in the nitrogen cycle of sediment samples taken from
the West Decker Mine settling pond 34
10. Most probable number estimations of organisms potentially
functional in the sulfur cycle 37
11. Survival of two acidophilic iron oxidizing isolates, TF-1 and
TF-2, in sterile settling pond water 40
12. Incubation of Thiobacillus ferrooxidans with coal 43
13. Results of respirometry studies on two isolates of
Thiobacillus ferrooxidans 44
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Number Page
14. Results of in situ measurements of sulfate reduction in
sediments oT^the West Decker Mine settling pond 45
APPENDIX - Water chemistry and algal productivity data,
West Decker Mine settling pond
A- 1. Water chemistry data, 27 July 1976 58
A- 2. Water chemistry data, 24 August 1976 59
A- 3. Water chemistry data, 19 September 1976 60
A- 4. Water chemistry data, 21 October 1976 61
A- 5. Water chemistry data, 18 November 1976 62
A- 6. Water chemistry data, 14 December 1976 63
A- 7. Water chemistry data, 12 January 1977 64
A- 8. Water chemistry data, 9 February 1977 65
A- 9. Water chemistry data, 6 April 1977 , 66
A-10. Productivity estimates at Site 3 67
A-11. Pigment concentrations of samples taken at Site 3 68
A-12. Pigment and bioaccumulation data for periphytic populations ... 69
A-13. Summary of results of laboratory algal bioassays 70
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ACKNOWLEDGMENT
We gratefully acknowledge the assistance of members of the Fisheries
Bioassay Laboratory, Montana State University, and Department of Chemistry,
Colorado State University, in analyses of water samples, and also the in-
valuable contributions of Richard Gregory, Paul Garrison, and Stephen Whalen
of the Montana Cooperative Fishery Research Unit. Marilyn Nyquist and Jerry
Claridge of the Department of Microbiology, Montana State University, pro-
vided competent technical assistance. The Decker Coal Company of Sheridan,
Wyoming, permitted us to undertake this study, and personnel at the Decker
Mine were cooperative and informative. Chemical analyses of sediment samples
were performed by Duane Klarich of the Montana State Board of Health.
Gratitude is expressed to Michael Marcus, Rosemarie C. Russo, John Schillinger,
David Stuart, Kenneth Temple, and Robert V. Thurston for their advice,
ideas, and guidance in the preparation of this manuscript.
This research was funded by the U.S. Environmental Protection Agency,
Environmental Research Laboratory-Duluth, Minnesota, 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
Approximately one-half of the nation's known coal reserves are located
in a six-state sector of the West which includes Colorado, Montana, North
Dakota, South Dakota, Utah, and Wyoming. This geographical area is desig-
nated by geologists as the Northern Great Plains and Rocky Mountain Coal
Provinces and contains coal deposits ranking from lignite to bituminous
(U.S. Environmental Protection Agency 1976). Major scale efforts to remove
these resources by surface extraction methods are ongoing and proposed.
Both the quality of the coal and the effects of land disturbance caused
by surface coal mining differ in the western reserves compared to those in
the East and Midwest. Coal from the Northern Great Plains has a lower
sulfur content (by weight) than eastern and midwestern coal, averaging 0.6
percent and ranging from 0.1 to 4.0 percent. In these low sulfur coals, the
relative percentage of organic sulfur tends to be higher; thus, there is a
comparatively lower amount of inorganic sulfur such as that found in the
minerals pyrite and marcasite. The potential for acid production via pyrite
dissolution by subsurface waters exists in both the East and West. Because
of the lower pyritic content of overburden materials and coal and the high
buffering capacity of surface waters in coal-rich regions of the West, acid
mine drainage is not widespread. In addition, rubblized overburden is not
subjected to high annual precipitation in the semi-arid western states.
Lower potentials for water-initiated erosion may also exist; however the
sparseness of vegetation decreases the stabilization of western soils so
that sedimentation of watersheds in mining-impacted areas may prove prob-
lematic (U.S. Environmental Protection Agency 1976). The soluble salts
content of overburden materials in western strip mines such as those in
Colorado (McWhorter et al_. 1975) may have the most significant pollution
impact on water quality.
Although information on the quality of coal and overburden, and the
quantity of precipitation, has permitted speculation on the nature of en-
vironmental perturbations from surface coal mining in the West, detailed
studies are needed to assess their magnitude. Specifically, a paucity of
information exists on the quality of waters originating from surface mined
areas (Gilley et ah 1976).
In November 1975 investigations were initiated on water quality altera-
tions associated with activities at the West Decker Mine, a sizeable open
pit mine in the Fort Union Formation of the Northern Great Plains Coal
Province. Specifically, an evaluation of the role of a coal mine sedimenta-
tion pond in determining the chemical composition of mine discharge waters
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was made so that recommendations for improvements in pond design may be
applied to the operation of future mines.
The Decker Mine, operated by Decker Coal Company, a subsidiary of Peter
Kiewit Sons' Company of Sheridan, Wyoming, and Pacific Power and Light
Company of Portland, Oregon, is located in southeastern Montana immediately
adjacent to the Tongue River Reservoir (Figure 1). The area of the actively
mined pit (effective July 1977) was 193 hectares. Mining operations are
currently expanding to include areas to the north and east of the present
mine site (Figure 2). When expansion is complete, Decker Coal Company will
be the largest subbituminous coal producer in the world. The present mine
at Decker discharges an effluent into the Tongue River flood plain at the
upper end of the reservoir. The two additional proposed mines will also
discharge mine waters directly or indirectly into the reservoir.
The primary function of the settling or sedimentation pond at the West
Decker Mine is to reduce the turbidity of the mine drainage (Decker Coal
Company personnel, personal communication). However, with the anticipated
intensification of coal mining in the vicinity of the Tongue River Reservoir,
additional functions such as nutrient transformations, heavy metal accumulation,
and general water quality alterations should be studied.
The present investigation was integrated with a separate study on the
limnology of the Tongue River Reservoir (Garrison et al_. 1975; Whalen et aL
1976; Whalen and Leathe 1976; Gregory 1977) as welTas other research pro-
jects. The settling pond effluent is projected to be used as a source of
water to fill and maintain a proposed northern pike spawning marsh and
waterfowl nesting site (Gregory 1976). It is desirable that the quality of
the effluent be acceptable for this purpose as well as for irrigation of
Decker's reclamation sites, if needed in times of drought.
The function of the settling pond in altering the quality of mine dis-
charge water was examined by three approaches. First, water samples from
the pond were analyzed for a wide spectrum of chemicals in an attempt to
determine how the pond water differed from groundwater and surface water
of the same region. Second, the algal productivity of the pond was esti-
mated. Third, methods for enumeration and indices of biological activity
were used to study the function of selected microbial populations in the
water column and surface sediment of the settling pond. Through these
approaches, the role of the pond in the retention of chemicals from coal
and overburden and the roles of microbial populations in the transformation
of chemical substances were elucidated.
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I
I
It
\_
M 0
•
Helena
Bozemon
I
Fort Union Coal Region
Figure 1. Map of Montana showing location of study area.
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TONGUE RIVER
RESE R VOIR
Figure 2. Map of the Tongue River Reservoir showing the locations of the
present and future mines operated by Decker Coal Company.
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SECTION II
CONCLUSIONS
1. The settling pond effluent from the West Decker Mine discharges
into the Tongue River flood plain. The quality of this discharge water was
sufficient to meet Montana state standards for coal mine effluents. Although
the evaluation of microbial and chemical processes within the settling pond
was hampered by its irregular operation, the pond altered the quality of in-
flowing mine drainage water with respect to a limited number of chemical
parameters.
2. Although acidophilic iron and sulfur oxidizing bacteria, which con-
tribute to the formation of acid mine drainage in the East and Midwest, were
consistently detected in the settling pond and at other locations near and
within the West Decker Mine, acid mine water conditions were not observed.
The activities of these bacteria may be restricted to microzones in the over-
burden or coal in which acid production is neutralized by the presence of
carbonate and bicarbonate minerals.
3. The presence of considerable activity of sulfate-reducing bacteria
along with significant amounts of metal-bound sulfides in the settling pond
sediments make a strong case for the contribution by these organisms to the
precipitation of heavy metals and possible detoxification of the pond water.
However, average concentrations of mercury in pond samples collected on nine
occasions during this study ranged from 0.09 to 0.81 ug/liter; these concen-
trations are higher than 0.05 pg/liter, the maximum recommended for fresh-
water aquatic life and wildlife by the U.S. Environmental Protection Agency
(1976b). A laboratory bioassay test alga, inoculated into pond water, did
not show growth inhibition characteristic of that caused by heavy metals.
4. Maximum algal productivity within the mine pond, even though
moderate, improved the quality of the pond water and therefore improved
the effluent discharge from the pond onto the Tongue River flood plain,
primarily by contributing to the oxidation of sulfide, a chemical toxic
in very low concentrations.
5. Laboratory algal bioassays, testing water collected from the set-
tling pond, indicated that the pond was nutrient limited and phosphorus was
most frequently the limiting factor. The pond was periodically enriched
with nitrogen, apparently by water seepages from an area used for storage
of ammonium nitrate explosives located directly adjacent to the pond. In
water samples taken after or during nitrogen enrichment, growth of the bio-
assay alga was never nitrogen limited.
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SECTION III
RECOMMENDATIONS
The principal recommendations are listed below; these are discussed in
Section VII.
1. A consideration of Hill's (1976) discussion of design parameters
such as "(1) capacity and size to meet water quality criteria, (2) storage
volume, (3) number of ponds, (4) location of pond, (5) shape of pond, (6)
inlet design, (7) outlet design, (8) cleanout procedures, and (9) close
down" would be helpful in improvement of the present operation at West
Decker or in the initial design of sedimentation basins for Decker Coal
Company's future mines. The physical aspects of sedimentation pond design
should be strongly interfaced with a consideration of biological activity
within the pond system.
2. A two-pond system may be more efficient for improving the quality
of coal mine drainage waters. A deep primary pond could serve two purposes,
one of which would be to facilitate sedimentation since it would be less
subject to wind-driven mixing. Zones of anaerobiosis could develop in
deeper waters and promote bacterial sulfate reduction which would remove
heavy metals and other elements from solution. Design considerations should
be such that adequate contact between metals and bacterially-generated sul-
fide is assured. A shallow secondary pond would permit the biological
uptake of nutrients such as those contributed from nitrogen explosives and
carbonaceous materials in the coal.
3. Concentrations of methylmercury should be monitored in coal mine
sedimentation ponds expecially when pond water is to be utilized directly
as a source for fish culture, or when pond effluent may present a source
of mercury pollution to receiving waters outside the mine. Forms of this
element are readily accumulated and retained in biological systems.
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SECTION IV
DESCRIPTION OF THE STUDY AREA
The settling pond system at the West Decker Mine (Figure 3) is located
within T9S, R40E, S16. Mining activities have interrupted the normal flow
of groundwater toward the Tongue River at the Decker Mine site. The most
important aquifers to be intercepted by mining are the coal seams (Van Voast
and Hedges 1975). As a result, groundwater flows into the mine pit and is
pumped out so that it will not interfere with mining operations. This
"altered" groundwater from a section of the mine was collected in a sump
from which it was* pumped into the settling pond. In addition, the settling
pond received runoff from a relatively small drainage area around it. The
water level in the settling pond was controlled by a standpipe at its
southern end. Overflow water, referred to as the mine effluent, was dis-
charged into the Tongue River flood plain.
At the time of this study, the settling pond was approximately one
meter in depth with an area of 1.2 hectares. Retention time was approxi-
mately 6.2 days. From July 1975 to July 1976 the outflow averaged 1.5 x
106 liter per day (Decker Mine personnel, personal communication). During
the course of this study, water moved through the settling pond system on
an interrupted basis. The pond underwent changes in morphometry as well.
These deviations from initial conditions, summarized in Table 1, undoubtedly
influenced the chemical and biological parameters and are considered in
interpretation of the data.
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I Influent
North Pond, Surface
North Pond, Bottom
South Pond, Surface
3 South Pond, Mid-depth
South Pond, Bottom
Withdrawal
Boat Marina
Effluent
evaporative
losses
precipitation and
runoff
output in effluent
EFFLUENT
withdrawal
for dust
control
TONGUE RIVER
FLOOD PLAIN
meters
Figure 3. Map of the settling pond system at the West Decker Mine showing
sources of chemical input and output, and locations of sampling
sites.
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TABLE 1. MONTHLY DESCRIPTION OF THE SETTLING POND SYSTEM AT THE WEST DECKER MINE
Date of Sample Collection
Pond Description
29 June 1976
28 July 1976
24 August 1976
19 September 1976
21 October 1976
18 November 1976
14 December 1976
12 January 1977
9 February 1977
6 April 1977
Sump pond and northern arm of settling pond buried; pond system no longer
completely resembling illustration in Figure 3; increased mining activity
immediately adjacent to pond.
Two sources of influent piped to pond, one from buried sump and other from
mine pit; effluent continuous.
Influent and effluent intermittent.
Influent and effluent intermittent.
No influent except for one observed influx of very turbid water; effluent
continuous; water in pond full of suspended particulates.
No influent or effluent; pond stagnant; thin ice cover over pond surface;
water very turbid.
Northern end of pond dredged, resulting in deepening of part of pond and
lowering of water level; pond stagnant but clear; ice cover from 15 to
25 cm thick.
Pond still stagnant but clear; water level approximately the same as in
December 1976; ice cover 25 cm thick.
Pond stagnant; water level lower than in January; ice cover from 20 to
40 cm thick; evidence of turbid runoff on top of ice.
No ice cover; influent intermittent; effluent restricted but continuous.
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SECTION V
MATERIALS AND METHODS
SAMPLE COLLECTION
Between November 1975 and June 1976 ten collections of water and sedi-
ment samples were made at the West Decker Mine settling pond system. Water
samples for algal bioassays were collected in acid-cleaned, sterile, two-
liter plastic containers from the sump pond (source of influent to the
settling pond) and the settling pond effluent. Selected bacterial popula-
tions were estimated in surface sediment samples collected from the sump and
settling ponds. The most efficient and aseptic instrument for sediment
collection was a Phleger core sampler with removable, autoclavable, butyrate
liners (Hydro Products, San Diego, California). All samples were kept
well-chilled while in transit to Montana State University (MSU) in Bozeman,
where they were processed within 24 hours.
More intensive studies of the settling pond were initiated in July 1976
and continued through April 1977. During that time bacteriological studies
and most water analyses were performed at a field research station located
immediately adjacent to the Tongue River Reservoir. Water samples for
chemical analyses were collected in appropriate acid-cleaned glass or plas-
tic bottles at 3 to 6 sites within the pond system. Locations of the samp-
ling stations (Figure 3) were chosen to represent sources of inflowing,
intermediate, and outflowing water. Site 1 corresponded to the major source
of inflowing water, whereas Site 4, the withdrawal, and Site 6, the efflu-
ent, were both sources of outflowing water. The location of Site 5, desig-
nated "boat marina" because our small sampling vessel was moored there, was
selected to represent a portion of the pond possibly enriched by the am-
monium nitrate explosives stored in vats on land adjacent to the pond. The
north and south portions of the pond were sampled at Sites 2 and 3, respec-
tively. The settling pond, in addition to being a sedimentation basin,
served as a reservoir of water for dust control. Water for this purpose was
removed by pumping at Site 4.
Both surface and bottom water samples were taken at Site 3 from July
through November 1976, and thereafter only from Site 2. Fewer sites were
sampled when the pond stagnated, and there were no sources of inflowing and
outflowing waters. The use of a homemade Van Dorn-type apparatus facili-
tated the collection of bottom samples. Measurements of temperature and
dissolved oxygen were taken simultaneously with sample collection. All
samples were kept chilled while in transit to the Tongue River Reservoir
Research Station.
10
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Collection of water samples for productivity estimates was made at
Site 3. Samples for the construction of diurnal oxygen curves were taken by
a suction and flushing system similar to that of Welch (1968). Chlorophyll
a concentrations and *4C productivity were estimated on mid-depth samples
taken with the Van Dorn apparatus. Test water for algal bioassays was also
collected from this site except when the influent and effluent were
continuous.
Water and sediment samples for microbial studies were collected from a
wide variety of locations within the pond system, the mine, and areas out-
side the mine. These locations are described in subsequent sections of this
report. Sediment samples were taken either by the Phleger core sampler or
an Ekman dredge (Wildlife Supply Company, Saginaw, Michigan). Sterile
disposable syringes of 1-, 3-, and 10-ml capacity (Becton, Dickinson and
Company, Rutherford, New Jersey) were used to subsample from the sediment
collected. Sterile plastic containers served as collection vessels for
water samples.
In November and December 1976, pond sediments were collected for ele-
mental analysis by the Montana State Board of Health in Billings. One
sample was collected at Site 3 in November, and Sites 2 and 3 were both
sampled in December. Grab samples, taken with an Ekman dredge, were placed
in plastic bags and kept well-chilled in transit to Billings for analysis.
MEASUREMENT OF CHEMICAL PARAMETERS
Immediately after collection, water samples were taken to the Tongue
River Reservoir Research Station where they were either preserved or pre-
pared for analysis. Methods for sample preservation or pretreatment are
outlined in the flow chart in Figure 4. Alkalinity'determinations and
nutrient (nitrogen and phosphorus species) analyses were performed in the
laboratory at the research station as soon as possible after sample collec-
tion. The analyses for silica as silicate, total iron, dissolved oxygen,
sulfate, and sulfide were generally completed within 24 hours of sample
collection. Sulfate concentrations were determined on samples delivered to
MSU Fisheries Bioassay Laboratory. In addition, levels of both sulfate and
sulfide were measured on a restricted number of sites involved in the micro-
bial studies. Because a wide spectrum of chemicals were analyzed by differ-
ent groups of individuals in this study, specific methods used and groups
are described in abbreviated form in Table 2.
Some chemical data from a single site (Site 4) had been collected on
samples of settling pond water prior to the initiation in July 1976 of more
intensive studies of the West Decker Mine pond. These data were provided
through the courtesy of the Tongue River Reservoir limnology study under-
taken by the Montana Cooperative Fishery Research Unit at MSU. Chemical
parameters were quantified according to the methods outlined in Garrison et
aJL (1975). Sediment samples submitted to the State Board of Health were
analyzed by atomic absorption spectrophotometry.
11
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Samples obtained from each of 3-6 sites
addition 1 ml
coned H«S04
(100 ml)
addition Wlnkler
reagents-
organic C dissolved 02
addition 0.1 ml
5% (w/v) HgCl2
(125 ml)
cool 4°C
|
total N
untreated
cool, 4°C
total P-/
total Fe K/
alkalinity^
specific conductance
filter through un-
weighed glass fiber
filter (Millipore
AP1504700) untreated
cool, 4°C
I
Mg
hardness
Cl
F
S04
turbidity
filter through unweighed
glass fiber filter
(Millipore AP1504700)
ro
-reagents added in the field.
- analyses performed as soon as
possible after sample collection.
filter through
0.45 Mm filter
(Mlllipore HAWP04700)
0.5 ml coned 2 ml 5% (w/v)K2Cr907
H2S04 ' " ' " •••- -
(250 ml)
As
Se
10 ml redistilled
HN03
(200 ml)
total non-
filterable
solids
(1 liter)
untreated
cool, 4°t£
|
N03-N
N02-N
NH3-N
Si02
ml redistilled HN03
(500 ml)
Cd
Pb
Na
K
Figure 4. Description of the treatment of water samples obtained from the West Decker Mine
settling pond system pnor to performing chemical analyses.
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TABLE 2. DESCRIPTION OF THE METHODS USED FOR THE CHEMICAL ANALYSES OF WATER SAMPLES FROM THE SETTLING POND SYSTEM AT THE WEST DECKER MINE
Parameter
Method of analysis
Instrumentation Laboratory performing analysis
Reference
Ca
Mg
Hardness
Na, K
Alkalinity
HC03, C03
F
Cl
S04
Silica as Si02
02
NU3-N
N02-N
NH3-N
Total N
EOTA titrimetric method
Computation from Ca & hardness
EDTA titrimetric method
(July, August) flame emission
(Sept-Feb) atomic absorption
(flame)
Potentionetric
Computation from alkalinity
Electrode method
Mercuric nitrate method
Turbidimetric method
Phenylenediamine
Molybdosilicate complex
Meter (July-Sept)
Azide modification of
iodometrk (Oct-Feb)
Mullin & Riley reduction
Nitriver
Hypochlorite (July-Oct)
Modification of phenol
hypochlorite (Nov-Feb)
Acid digestion & hypochlorite
(July-Oct)
Acid digestion & modification
of phenol-hypochlorite
(Nov-Feb)
Buret
Buret
Instrumentation Lab
AA/AE Model 151
spectrophotometer
Varian Techtron AA-5
spectrophotometer
Buret
Fluoride ion elec-
trode, Orion 94-09
Buret
Varian UV-Vis
spectrophotometer
Bausch & Lomb
"Spectronic 20"
Klett-Summerson col-
orimeter, Model 800-3
Yellow Springs D.O.
meter, Model 54
Buret
Fisheries Bioassay Lab, MSU
Fisheries Bioassay Lab, MSU
Fisheries Bioassay Lab, MSU
Dep. Microbiology, MSU
Dep. Chemistry, CSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Fisheries Bioassay Lab, MSU
Fisheries Bioassay Lab, MSU
Fisheries Bioassay Lab, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Bausch & Lomb
"Spectronic 20"
Bausch & Lomb
"Spectronic 20"
Klett-Summerson col-
orimeter, Model 800-3
Klett Summerson col-
orimeter, Model 800-3
Klett-Summerson col- Dep. Microbiology, MSU
orimeter, Model 800-3
Klett-Summerson col-
orimeter, Model 800-3
Am. Publ. Health Assoc. et ah 1976
Am. Publ. Health Assoc. et al.. 1976
Am. Publ. Health Assoc. et al. 1976
Varian AA-5 Instrument Manual
i
Am. Publ. Health Assoc. et ah 1971
Am. Publ. Health Assoc. et al.. 1971
Am. Publ. Health Assoc. et al.. 1976
Am. Publ. Health Assoc. et al.. 1976
Am. Publ. Health Assoc. et ah 1976
Strickland and Parsons 1972
Am. Publ. Health Assoc. et aj.. 1971
Am. Publ. Health Assoc. et al_. 1971
Barnes 1959
Hach Chemical Company 1973
Strickland and Parsons 1972
Strickland and Parsons 1972
-------
TABLE 2. Continued.
Parameter
Method of analysis
Instrumentation Laboratory performing analysis
Reference
Organic N Computation of difference
Ortho P04-P Single reagent
Total P Acid persulfate digestion
and single reagent
Organic P Computation of difference
Organic C Combustion infrared method
Total Fq Ferrozine reagent
Total nonfilter- Gravimetric after filtration
able solids
Total dissolved Computation from specific
solids conductance
Specific Meter
conductance
pH Meter
Turbidity Nephelometric method
Hg Cold vapor technique
As Automated hydride generation
Se Automated hydride generation
Pb Atomic absorption (flame)
Cd Atomic absorption (flame)
Klett-Summerson col-
orimeter, Model 800-3
Klett-Summerson col-
orimeter, Model 800-3
Beckman Infrared
Analyzer, Model IR315
Klett-Summerson col-
orimeter, Model 800-3
Mettler analytical
balance, type HIS
Labline mho meter
model mc-1, Mark IV
Beckman Expanded
Scale pH meter,
Model 76
Fisher OR-200
turbidimeter
Varian Techtron AA-5
spectrophotometer
Varian 1200AA spec-
trophotometer, Tech-
nicon Autoanalyzer I
Varian 1200AA Spec-
trophotometer, Tech-
nicon Autoanalyzer I
Varian Techtron AA-5
spectrophotometer
Varian Techtron AA-5
spectrophotometer
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Dep. Microbiology, MSU
Fisheries Bioassay Lab, MSU Am. Publ. Health Assoc. et al_. 1976
U.S. Environ. Protection Agency 1974
U.S. Environ. Protection Agency 1974
U.S. Environ. Protection Agency 1974
U.S. Environ. Protection Agency 1974
Am. Publ. Health Assoc. et aL 1971
Hach Chemical Company 1973
U.S. Environ. Protection Agency 1974
Garrison et al. 1975
Dep. Chemistry, CSU
Dep. Chemistry, CSU
Dep. Chemistry, CSU
Dep. Chemistry, CSU
Dep. Chemistry, CSU
Varian AA-5 Instrument Manual
Goulden and Brooksbank 1974
Goulden and Brooksbank 1974
Varian AA-5 Instrument Manual
Varian AA-5 Instrument Manual
-------
ALGAL PRODUCTIVITY
Productivity Estimates.
Productivity at Site 3 was estimated by measuring both diurnal changes
in the concentration of oxygen and the iji situ uptake of labeled inorganic
carbon (as NaH14C03 in 10 uCi ampoules fronTRew England Nuclear Corporation,
Boston, Mass.) on a monthly basis from July 1976 through December 1976. The
details of diurnal measurements and calculations are given in Odum and
Hoskin (1958). Dissolved oxygen concentrations were determined by the azide
modification of the iodometric method (American Public Health Association et
aK 1971). The radioactive carbon method was basically that first described
by Steeman-Nielsen (1952) and modified by others (Gurtz and Weiss 1972;
Vollenweider 1974). The suggestions of limnologists working on the Tongue
River Reservoir were particularly helpful for adapting this technique to the
settling pond at West Decker (Whalen and Leathe 1976; Stephen Whalen and
Paul Garrison, personal communication). Radioactivity was quantified by a
Beckman Model LS-100C liquid scintillation counter.
Chlorophyll Measurements.
Chlorophyll a, b, and c measurements of phytoplankton populations
within the settling pond were undertaken on nine water samples collected
between July 1976 and April 1977. Collection and extraction methods were
those of Whalen and Leathe (1976). Pigment concentrations were quantified
by measuring absorbance at 665, 645, and 630 nm on a Varian Techtron Model
635 ultraviolet-visible spectrophotometer, and calculated as described in
Strickland and Parsons (1972).
In May and September 1976, artificial substrates (glass slides) to
sample periphyton were placed both in the settling pond effluent (below the
flume) and within the pond proper. Chlorophyll concentrations of periphytic
populations developing on the slides after suitable periods were measured as
described above. Biomass accumulation on these same substrates was quanti-
fied by the methods of Marcus (1977).
Algal Bioassays.
Algal bioassays were conducted in the laboratory at MSU according to
the specifications of the Environmental Protection Agency (U.S. Environmental
Protection Agency 1971) on samples collected from the settling pond system.
The green alga, Selenastrum capricornutum Printz served as the test organism.
Relative fluorescence, measured with a Turner Associates Model 111 Fluor-
ometer, was used as an indirect measurement of algal biomass. Nutrient
limitation was determined by the production of significantly larger popula-
tions of cells with the addition of one or more spikes. Spikes added to the
test waters included 1.0 mg/liter of N as NaN03, 0.05 mg/liter of P as
K2HP04, and 1.0 mg/liter of EDTA as
15
-------
BACTERIOLOGY
Estimation of Selected Bacterial Populations.
A wide variety of physiological groups of bacteria potentially func-
tional in the nitrogen, sulfur, and carbon cycles were enumerated in sedi-
ment samples and, to a lesser extent, water samples collected within the
settling pond system at West Decker and other locations. Estimation of
these populations was accomplished by the five-tube most probable number
(MPN) method for the nitrogen and sulfur cycle organisms and the surface
plate count technique for aerobic heterotrophs which function in the carbon
cycle. Numbers of sulfur and nitrogen organisms were derived from standard
tables giving numerical estimates and their 95% confidence intervals; a full
discussion of the MPN technique is given in Alexander (1965a) and Meynell and
Meynell (1970). In performing surface plate counts, the suggestions of
Clark (1971) were valuable for optimizing results. The different media,
methods of detection used, and references to methods used for the estimation
of selected bacterial populations are summarized in Table 3. Samples were
diluted in sterilized water from site of sample collection.
Enrichment of Selected Bacterial Populations.
Fresh samples of coal from the two principal seams mined at Decker
(Dietz-1 and Dietz-2) were obtained from drilling operations. Chunks were
crushed with a sterilized mortar and pestle. Approximately 10 grams of
crushed sample were inoculated into 90 ml of 9K salts plus ferrous iron
(Silverman and Lundgren 1959). After one month, attempts were made to
subculture bacteria from the coal-inoculated flasks into test tubes contain-
ing the same medium.
Sediment samples were collected from each of the following locations:
Tongue River upstream from railroad bridge above the reservoir, Tongue River
near rivulet believed to be from swampy area below West Decker Mine effluent,
Tongue River downstream from this rivulet, directly below flume, and branch
of rivulet resulting from effluent. Triplicate one-gram subsamples were
inoculated into 50 ml of 9K salts plus ferrous iron or elemental sulfur.
After 16 days, contents of enrichment flasks were subcultured to tubes con-
taining the same medium.
Purification, Tentative Identification, Growth and
Survival of Acldophi'li'c Iron Oxidizing Bacteria
Most probable number tubes positive for the oxidation of iron were
purified by streaking on the ISP medium of Manning (1975). If these iso-
lates also produced acid when inoculated into 9K salts plus elemental sulfur
(Silverman and Lundgren 1959), they were tentatively identified as
Thiobacillus ferrooxidans (Buchanan and Gibbons 1974).
The survival of two ,such isolates, TF-1 and TF-2, was evaluated by the
following method: cells were grown in 9K salts plus ferrous iron at pH 3,
harvested, washed (Silverman and Lundgren 1959), and inoculated into sterile
16
-------
TABLE 3. METHODS USED FOR THE DETECTION AND ENUMERATION OF SELECTED BACTERIAL POPULATIONS
Physiological Process
NITROGEN CYCLE
Ammonifi cation
Nitrification
Step 1
Step 2
Denitrification
Nitrogen fixation
(Azotobacter)
SULFUR CYCLE
Sulfite reduction
Elemental' sulfur
oxidation
Thiosulfate
oxidation
Reaction Detected Method of Enumeration
R-NH, •> NH, most probable number
2 3 (MPN)
NH3 •»• N02 MPN
N02 •» N03 MPN
N02,N03 •* N2,N20 MPN
N£ -» cellular N MPN
S04 •> H2S MPN
S° -> S04 MPN
S203 •* S04 MPN
Culture Medium
2.0% (w/v) peptone
broth
ammonium-calcium
carbonate broth
nitrite-calcium
carbonate broth
asparagine-citrate
broth
sucrose-mineral
salts broth
Medium E
acidified 9K salts
w/elemental sulfur
neutral thiosulfate
broth
Method of Detection
yellow color w/ addition of
Nessler's reagent
pink color w/addition of
Griess-Ilosvay reagent; pink
color w/addition of both Devarda's
alloy & Griess-Ilosvay reagent
no pink color w/addition of
Griess-Ilosvay reagent; pink
color upon addition of Devarda's
alloy
green to blue color change
(increase alkalinity), presence
of gas
pellicle formation on surface
of broth
blackening due to formation
of ferrous sulfide
red upon addition of thymol
blue (increase acidity)
macroscopic examination for
pellicle formation; yellow
Reference
Seeley & Vandemark
(1972)
Alexander & Clark (1965)
and
Matulewich et al. (1975)
Alexander (1965b)
Clark (1965)
Postgate (1966)
Silverman and Lundgren
(1959)
Vishniac and Santer
(1957)
upon addition of brom thymol
blue (increase acidity)
IRON CYCLE
Iron oxidation
_ _
Fe •* Fe
MPN
acidified 9K salts
w/ferrous sulfate
orange-brown precipitate of
ferric iron
Silverman and Lundgren
(1959)
CARBON CYCLE
Aerobic, hetero-
trophic growth
growth on carbon-
aceous medium
plate count
1/2-strength iron
peptone agar
colonial growth
Ferrer et al. (1963)
-------
West Decker pond water (pH 8). The count of viable organisms at different
times was determined by the MPN technique.
TF-1 and TF-2 were also grown in batch culture (10 liters and 4 liters,
respectively) in a Microferm Model MF-214 fermenter to test the correlation
between cell number and ferrous iron concentration. Cell numbers were
determined by direct microscopic counts in a Petroff-Hauser chamber. The
concentration of ferrous iron was measured by titration with potassium
permanganate (Skoog and West 1976). The initial ferric iron concentration
was taken as zero, and differences between the initial and subsequent fer-
rous iron concentrations were taken as the amount of ferric iron present.
Leaching Experiments with Thiobacillus ferrooxidans
Ten-gram quantities of 28- to 80-mesh rider seam coal obtained from
West Decker were added to 250-ml Erlenmeyer flasks containing 100 ml of 9K
salts. Sodium azide (0.03g) and iron (4.42g FeS04'7H20) were added to
some of the flasks. All flasks were inoculated with 0.2 ml of a washed
suspension of T. ferrooxidans containing 108 cells per ml. After four hours
to permit equilibration, pH was measured (Beckman Model SS-3 Zeromatic pH
meter) and the amount of acidity was determined titrimetrically (American
Public Health Association et al_. 1976). Acidity and pH values were redeter-
mined after a 33-day incubation period.
Physiological Studies of fhiobacillus ferrooxidans using Respirometry
Oxygen consumption by T. ferrooxidans was measured in a Gil son Differ-
ential Respirometer. Cells were grown in batch culture as previously de-
scribed. Each respirometer vessel contained 0.2 ml of washed cells
(approximately 5 x 109 cells) and 2.8 ml of basal salts plus an energy
source. Energy sources were the following: iron, 100 umoles (as FeS04*7H20);
thiosulfate, 100 umoles (as Na2S203-5H20); elemental sulfur, 50 mg;
or glucose plus yeast extract (0.1% w/v and 0.5% w/v, respectively). The
center well of each vessel contained 0.2 ml of 20% (w/v) KOH and a filter
paper wick as a C02 trap. The experiments were performed at 28 C, with an
agitation rate of 140 oscillations per minute. The gas phase in the vessels
was air. All results were corrected for endogenous respiration.
Sulfate Reduction in Pond Sediments
Jn situ rates of sulfate reduction were measured in the West Decker
settling pond sediments on three occasions (September, October, and December
1976) using the technique of Ivanov (1964). Radioactive sulfate as H235S04
(New England Nuclear Corporation) was incubated with samples of settling
pond sediment. After a suitable incubation period, biological reactions
were terminated and evolved sulfide was fixed with a solution of 3.5% w/v
cadmium acetate in 4% v/v acetic acid. Upon return to the laboratory at
MSI), the radioactive cadmium sulfide precipitate was subjected to acidifi-
cation and heat which drove off the sulfide. Evolved sulfide was trapped in
an absorption column containing cadmium acetate. The radioactivity of this
precipitate was then quantified with a liquid scintillation counter (Beckman
18
-------
LS-100C). A lactate spike (300 nig/liter) was added to one set of experi-
mental vessels in both October and December. The rate of sulfate reduction
was calculated by the following equation (Ivanov 1964):
mg H^S per liter per day =
(concentration of SOp (radioactivity of H235S) (24 hr) (1.06)
(radioactivity of H235S04) (duration of experiment in hours)
19
-------
SECTION VI
RESULTS AND DISCUSSION
CHEMICAL PARAMETERS
Nutrients, Cations. Anions, and Other Parameters
Results of chemical analyses performed on samples taken within the pond
are presented in Table 4. In the data collected from July 1976 to February
1977, it should be noted that the values listed as highest and lowest in the
ranges are actually means of concentrations of chemical parameters for three
to five sites sampled within the pond on a particular sampling trip. Averag-
ing the data from different pond sites collected on the same oqcasion was
deemed justifiable because these values did not differ markedly. Chemical
data from the pond are presented in summary form in Table 4 and are given in
more detail in the Appendix, Tables A-l through A-9. Chemical data provided
through the courtesy of the Montana Cooperative Fishery Research Unit
(November 1975 to June 1976) are included in Table 4 because they essen-
tially characterized the pond prior to increased nearby mining activity and
to changes in operation and morphometry. They will be referred to in the
discussion only in comparison to our data.
Some concentrations, particularly those of nitrogen species, were
highly variable from month to month as evidenced by the wide ranges in Table
4. This may indicate that monthly sampling was too infrequent to character-
ize a heterogeneous system such as the settling pond, which was subjected to
random changes in mining activity.
Concentrations of dissolved oxygen, bicarbonate, sulfate, nitrogen
species, and total dissolved solids (specific conductance) were markedly
different in the November 1976 through February 1977 samples compared to
previous data. These parameters, with the exception of dissolved oxygen,
showed increased levels in response to several factors. Notably higher-
concentrations of nitrogen reflected the influence of overburden blasting
with ammonium nitrate explosives. These materials were stored in vats
approximately 50 meters from the pond, and it is very likely that they also
periodically enriched the pond waters. Van Voast and Hedges (1975) also
observed sporadic abnormally high concentrations of nitrate in the pond
effluent and attributed them to overburden blasting or to dissolved
nitrate-containing substances from disturbed materials. The higher concen-
trations of dissolved nitrogen species in the settling pond, compared to
those in the Tongue River as determined by Whalen and Leathe (1976), were an
indication of the more intensive mining activities in the vicinity of the
pond.
20
-------
TABLE 4. RESULTS OF CHEMICAL ANALYSES PERFORMED ON SAMPLES FROM THE
WEST DECKER MINE SETTLING POND
Nov 1975-Jun 1976
Average (Range)
[No. of analyses]
Jul 1976-Feb 1977
Average (Range)
[No. of analyses]
Temperature (°C)
Specific conductance
(umho/cm)
PH
Turbidity (NTU)
13.3
(3.0-25.3)
[11]
1528
(1129-1728)
[11]
8.29
(7.65-8.98)
[11]
21.4
(3.2-44.0)
[10]
9.9
(0.3-22.9)
[7]
1865
(1254-2831)
[8]
8.14
(7.85-8.50)
[8]
12.1
(4.4-34.0)
[4]
Calcium (me/liter)
Magnesium (me/liter)
Sodium (me/liter)
Potassium (me/liter)
Chloride (me/liter)
Fluoride (me/liter)
Sulfate (me/liter)
1.96606
(0.98802-2.87424)
[10]
4.11300
(2.96136-4.39263)
[10]
10.87500
(7.39500-13.70250)
[10]
0.21735
(0.18155-0.28127)
[10]
0.23414
(0.02257-0.30467)
[10]
0.05790
(0.04738-0.07422)
[10]
6.45522
(3.81189-9.85259)
[11]
2.66396
(1.37225-3.92713)
[7]
3.37924
(1.62875-5.06722)
[7]
14.43500
(9.27860-22.76360)
[7]
0.14140
(0.13475-0.22169)
[6]
0.08328
(0.00282-0.16221)
[5]
0.11212
(0.05632-0.18582)
[6]
6.12131
(4.62430-8.74860)
[6]
21
-------
TABLE 4. Continued.
Nov 1975-Jun 1976 Jul 1976-Feb 1977
Average (Range) Average (Range)
[No. of analyses] [No. of analyses]
Total alkalinity 518.6 703.0
(ing/liter CaC03) (382.5-595.5) (431.4-1223.0)
[11] [8]
Total hardness — 273
(mg/liter CaC03) (194-431)
[7]
Silica (mg/liter Si02) 13.5 10.8
(6.8-23.0) (7.4-14.9)
[10] [5]
Dissolved oxygen (mg/liter) 12.3 7.0
(10.1-14.4) (1.3-11.1)
[11] - [8]
Dissolved iron (mg/liter) 0.019 0.015
(0-0.037) (0.013-0.016)
[10] [2]
Total iron (mg/liter) — 0.099
(0.057-0.187)
[8]
Total dissolved solids 1024 1250
(mg/liter) (756-1158) (840-1897)
[11] [8]
Total non-filterable solids — 11.6
(mg/liter) (5.6-20.5)
[8]
Organic carbon (mg/liter) 5.9 6.9
(3.0-8.8) (4.7-9.1)
[9] [2]
Nitrate-Nitrogen (mg/liter) 0.378 5.8
(0.020-1.133) (0.098-21.8)
[10] [8]
Nitrite-Nitrogen (mg/liter) 0.032 0.107
(0-0.108) (0.002-0.279)
[11] [8]
22
-------
TABLE 4. Continued.
Nov 1975-Jun 1976
Average (Range)
[No. of analyses]
Jul 1976-Feb 1977
Average (Range)
[No. of analyses]
Ammonia-Nitrogen (mg/liter)
Total nitrogen (mg/liter)
Inorganic nitrogen (mg/liter)
Organic nitrogen (mg/liter)
Orthophosphate phosphorus
(mg/liter)
Total phosphorus (mg/liter)
Organic phosphorus (mg/liter)
0.329
(0.030-0.952)
[9]
0.793
(0.065-2.028)
[9]
0.032
(0.003-0.078)
[11]
0.013
(0.001-0.042)
[11]
0.029
(0.005-0.048)
[11]
1.40
(0.109-3.82)
[8]
8.6
(0.406-25.2)
[8]
7.3
(0.267-23.0)
[8]
1.250
(0.032-3.344)
[8]
0.005
(0.001-0.008)
[8]
0.046
(0.021-0.063)
[8]
0.036
(0.020-0.055)
[8]
23
-------
From December 1976 through February 1977 the pond was stagnant and
ice-covered. Concentrations of dissolved oxygen were much lower than those
recorded by the Tongue River Reservoir limnologists (see Table 4). Stagna-
tion and ice cover prevented atmospheric exchanges and allowed processes
which consume oxygen to exceed those which release it.
The chemical oxygen demand may have been high at this time because in
early December the northern end of the pond was dredged, and reduced chemi-
cals in the sediments were released into the water column. The combination
of increased mining activity, pond stagnation, dredging, and ice cover
appear to have greatly influenced the concentrations of certain chemicals in
the water column, and were responsible for the differences in pond water
chemistry between the summer and winter sampling periods.
Comparison of the influent and effluent was only possible for a few
months (July to October 1976). Although a new pumphouse was completed in
the early spring of 1977 for pumping drainage waters from an underground
pipe system into the pond, the flow into the pond was still not continuous.
Dredging the pond in early December deepened it. Because the water was then
below the standpipe, there was very little discharge into the Tongue River
flood plain.
Based on comparison of the analyses performed, the influent to the mine
settling pond was chemically different from the effluent. Inflowing waters
were characterized by relatively low dissolved oxygen, lower pH values, and
higher concentrations of iron. Specific conductance and total non-filterable
solids were greater in the effluent samples. Values for selected parameters
are given in Table 5. Waters entering the pond underwent oxygenation with
the concomitant loss of sulfide. Photosynthetic activity may have increased
the pH values within the pond resulting in a more alkaline discharge.
The West Decker Mine settling pond was designed to function as a sedi-
mentation basin. Greater quantities of suspended particulate matter were
detected in the settling pond than in the influent. This observation sug-
gested the importance of fugitive dust and runoff as contributors to the
levels of particulate materials within the pond. Continuous and heavy
traffic of trucks was observed on the roads immediately adjacent to the
pond. In addition, nearby overburden blasting produced noticeable clouds of
dust which eventually drifted over the pond. The pond was very shallow and
was subjected to considerable wind-driven mixing which may account for
relatively high concentrations of particulates. The effect of wind in re-
ducing the efficiency of sedimentation ponds has been discussed by Janiak
(1975). Suspended materials were largely abiotic in nature. Sampling may
have been too infrequent to collect data on intermittent, very turbid in-
flowing water (referred to as secondary influents) which contained signifi-
cantly higher concentrations of suspended materials. On 28 July 1976, a
very turbid secondary influent was sampled. It contained 115.6 mg/liter of
total non-filterable solids (total suspended solids) compared to 3.2 and
11.6 mg/liter of the primary influent and the settling pond, respectively.
Although the federal -government (U.S. Environmental Protection Agency
1977b) has advanced guidelines for the water quality of effluents from
24
-------
TABLE 5. SELECTED CHEMICAL PARAMETERS MEASURED ON WATER SAMPLES COLLECTED
FROM INFLUENT AND EFFLUENT WATERS OF THE SETTLING POND SYSTEM
AT THE WEST DECKER MINE (DATA ARE PRESENTED AS AVERAGE
VALUES OF FOUR MONTHLY DETERMINATIONS)
Parameters
Dissolved oxygen (mg/liter)
Specific conductance (jjmho/cm)
Total non-filterable solids (mg/liter)
pH
Sulfate (mg/liter)
Sulfide (mg/liter)
Sodium (mg/liter)
Total Iron (mg/liter)
SAR values-7
Influent
4.4
1338
3.2
7.46
256.0
0.23
224.0
0.196
5.094
Effluent
12.3
1471
15.1
8.36
283.0
not detectable
268.0
0.096
7.037
-SAR is mathematically expressed as
me/liter Na
me/1iter Ca + me/liter Mg
surface coal mines, individual standards for each mine may be modified at
the region or state level based on local conditions (rate of effluent dis-
charge, soil conditions of the receiving area, etc.). As of June 1977, the
effluent from the West Decker Mine settling pond has to meet the following
criteria (Montana Department of Health and Environmental Sciences 1977):
(1) total suspended solids of 30 mg/liter for a daily maximum; (2) the pH
value shall not be less than 6.0 standard units nor greater than 9.0 stan-
dard units; (3) total iron is limited to 3.5 mg/liter for a daily average
and 7.0 mg/liter for a daily maximum; (4) the concentration of oil and
grease shall not exceed 10 mg/liter.
The first three criteria are those suggested by the U.S. Environmental
Protection Agency (1977b). The level of total suspended solids for the West
Decker Mine has been modified by EPA Region VIII requirements. The fourth
criterion has been set by the State of Montana.
25
-------
Water samples were not analyzed for oil and grease as part of the
present study, but the data (Table 5) indicate that the other criteria were
met. The chemical characteristics of the pond effluent also have been re-
ported in detail in a limnological study of the Tongue River Reservoir
(Whalen and Leathe 1976). This study found that the concentrations of
sodium, sulfate, ammonia-nitrogen, nitrate-nitrogen, and bicarbonate were
elevated in the discharge from the settling pond, but that these chemicals
had virtually no measurable impact on the surface water quality of the
Tongue River based on theoretical loading calculations. Researchers investi-
gating the quality of other mine effluents entering the Tongue River reached
similar conclusions (Dettman and Olsen 1977). They reported that discharge
from the Big Horn Mine, approximately 50 river kilometers upstream from
Decker, also contained concentrations of these same chemicals which were
greater than those in the Tongue River; the concentrations of dissolved
conservative parameters downstream from the Big Horn Mine were not sig-
nificantly higher than above the mine.
Cations and anions are expressed in milliequivalents per liter in Table
4 to facilitate comparison. The ionic composition of inland surface waters
consists of four major cations, Ca , Mg , Na , and K , and four major
anions, SC-4, HCOa, CDs, and Cl~ (Wetzel 1975). The relative abundance of cations
and anions in the West Decker Mine settling pond compared to the Tongue
River above the West Decker Mine and to inland surface waters is as follows:
West Decker Mine
settling pond
Cations Na>Mg>Ca>K
Anions HC03>S04>C1
Tongue River above
mine effluent
(Garrison et al. 1975;
Whalen et al. 1976;
Whalen and Leathe 1976)
Ca>Mg>Na>K
HC03>S04>C1
Inland Surface Waters
(Wetzel 1975)
Ca>Mg>Na>K
C03>S04>C1
(all bicarbonate
considered as
carbonate)
The water of the settling pond showed a different predominance of cationic
species with the equivalent proportion of sodium exceeding proportions of
other cations by an order of magnitude. In addition, magnesium was greater
than calcium. Both of these cations exceeded potassium by an order of
magnitude. The aniom'c composition of the pond water followed the general
tendency for proportions of bicarbonate to dominate, with sulfate equiva-
lents exceeding those of chloride. Within the pH ranges measured, bicarbon-
ate accounted for almost all of the total alkalinity. These results were
similar to the order of anion predominance in samples of Tongue River water
and in the generalized scheme for inland surface waters. In the pond samples
collected from November 1976 through February 1977, the equivalent portions
of nitrate were greater than those of chloride and fluoride combined. This
was somewhat unusual because, although nitrate is of immense biological im-
portance, it does not contribute significantly to the anionic components of
natural waters unless they are highly enriched (Wetzel 1975).
26
-------
In typical inland waters of temperate regions, total hardness is approx-
imately equal to total alkalinity when both are expressed as mg per liter of
calcium carbonate. It is evident from Table 4 that total alkalinity exceeded
total hardness and that significant amounts of another cation, obviously
sodium, were present. The settling pond can be characterized as containing
bicarbonate water with sodium as the predominant cation and, in this respect,
it was like the groundwaters of the same region. A similarity between the
two waters was not unexpected because groundwaters from the overburden of
the Dietz-1 coal seam, and those from both the Dietz-1 and Dietz-2 coal
were eventually piped into the settling pond (Van Voast 1974). This simi-
larity, however, was limited; differences between the groundwaters and sur-
face water of the pond are best illustrated by Table 6 which is taken from
Whalen and Gregory (1977). Groundwater data for the construction of this
table were obtained from Van Voast (1974); the chemical parameters of the
mine effluent have been analyzed in the Tongue River Reservoir limnology
study (Garrison et aK 1975; Whalen et al_. 1976; Whalen and Leathe 1976).
The data in Table 6 indicate that the equivalent proportion (me/liter)
of sodium in the groundwater was greater than that in the settling pond
water. Van Voast and Hedges (1975) have reported that in aquifers within
the coal seams, groundwaters under pressure are supersaturated with sodium
bicarbonate. High levels of sodium are the result of dissolution of sodium-
rich feldspars and other minerals and, to some extent, base exchange reac-
tions (Roger Lee, U.S. Geological Survey, personal communication, 1978).
Water from the settling pond contained higher proportions of magnesium
and calcium in comparison to those in groundwater from the coal-bearing
aquifers. This observation agrees with the contention that minerals (such
as those containing magnesium and calcium) are more easily dissolved in rub-
blized overburden than they are in the undisturbed materials. McWhorter et
al_. (1975) suggested that the magnesium and calcium in runoff from spoils
sampled at the Edna Mine in Colorado resulted from the exposure of the
minerals gypsum, epsomite, dolomite, and calcite to leaching action. This
phenomenon may be operable at the West Decker Mine.
Perhaps the best reflection of the relative concentrations of sodium,
calcium, and magnesium in the two types of water is the sodium absorption
ratio (SAR). This ratio was derived to predict the magnitude to which irri-
gation water potentially undergoes cation exchange reactions in soil (Hem
1971). Water with values less than 4 will not disturb the nutritional
balance in crop plants, while SAR values less than 8 will not damage soil
structure (Bernstein 1967 i_n Whalen and Leathe 1976). The average SAR re-
ported by Whalen and Gregory (1977), given in Table 6, was similar to that
calculated for the influent and effluent of the settling pond (Table 5).
The value for groundwaters in the West Decker area was high, but that of
the pond water was below 8. Although not ideal for irrigation of mine
spoil reclamation sites, water from the settling pond would not cause ad-
verse effects if diluted sufficiently. The degree of dilution necessary
depends, of course, on the nature of the dilution water. If Tongue River
water were used, settling pond water would have to be diluted greater than
two-fold to produce an SAR value below 4.
27
-------
TABLE 6. COMPARISON OF CHEMICAL PARAMETERS OF GROUNDWATER SAMPLES OBTAINED
FROM AQUIFERS IN THE COAL SEAMS AT DECKER AND THE WATER
OF THE MINE SETTLING POND EFFLUENT-''
Parameter-
Ca++
Mg++
Na+
HC03"
so4=
Hardness (mg/liter as CaC03)
SAR
Dissolved Fe (mg/liter)
pH
Groundwater
0.17
0.08
18.56
18.50
0.09
i? (d?zl'\(~'
.Lc. ^ J^.tJ J
54.6
0.10
8.3
Mine effluent
1.65
3.49
11.04
9.78
6.15
257 (489)^
6.4
0.02
8.3
-' Whalen and Gregory 1977.
- Concentrations reported in milliequivalents/liter unless otherwise
indicated.
- Numbers in parentheses represent theoretical hardness, which is calculated
by assuming that (a) the total alkalinity is due to bicarbonate, and (b)
in a "typical" natural water, predominantly a calcium or calcium-magnesium
i » 1 I
bicarbonate system, the total hardness (chiefly due to Ca and Mg ) is
approximately equal to total alkalinity when both are expressed as mg
CaC03 per liter.
28
-------
Another parameter showing differences between the groundwater and the
settling pond water was sulfate; Table 6 indicates that sulfate concentra-
tions were much greater in the settling pond water than in groundwater. Van
Voast and Hedges (1975) reported that high sulfate concentrations in the
settling pond effluent, relative to those in the groundwaters, cannot be
explained solely by mixing of the groundwaters. They attributed this differ-
ence to the dissolution of sulfate from freshly crushed coal. However, coal
is not the primary source of the sulfur present in surface and groundwaters
in coal-bearing regions. Pyritic materials are also present in the over-
burden and, because large amounts of overburden must be disrupted during
mining, overburden may contribute much of the sulfur found in these surface
waters and groundwaters. Sulfate, like magnesium and calcium, may be leached
from the minerals gypsum and epsomite (McWhorter et al. 1975). It is pos-
sible that reduced inorganic sulfur such as that in pyrite was being oxi-
dized with the concomitant increase in concentrations of sulfate. This
oxidation process is responsible for acid mine drainage problems in mining
areas of the eastern and midwestern United States. Not all of the coal beds
in those areas, however, produce acid waters. For example, alkaline mine
waters associated with the Sewickley coal seam in Pennsylvania and West
Virginia are attributed to neutralization of acid by mineral carbonate
present (Temple and Koehler 1954).
Acidic drainage has not been reported at West Decker; the pH values of
the settling pond influent and effluent were always above neutral (Table 5).
The absence of acidic conditions has been attributed primarily to the high
buffering capacity of the regional waters, particularly the surface waters.
The presence of less pyritic material in western overburden and coal strata
may also reduce the potential for acid production. Acid mine drainage is
discussed in more detail in subsequent sections of this report.
Potentially Toxic Elements
Levels of possible toxicants in waters of the West Decker Mine settling
pond system are given in Table 7. According to the water quality criteria
of the U.S. Environmental Protection Agency (1977a), the levels of arsenic,
selenium, cadmium, and lead did not exceed those reported to be hazardous to
public water supplies or exceed that recommended for the protection of
aquatic life. Concentrations of mercury, however, exceeded the recommended
values for .the protection of freshwater aquatic life and wildlife by an
order of magnitude. Joensuu (1971) and Klein (1973) also reported that
relatively high concentrations of mercury are found associated with
coal-bearing strata. Because of negligible loading to, and dilution by, the
Tongue River, mercury was not detected in the river at concentrations above
that recommended by EPA (1977a). However, a spawning marsh for northern
pike, to be located in the flood plain in the region of the settling pond
discharge, is currently planned (R. Gregory, Montana Cooperative Fishery
Unit, personal communication, 1978). Chemical monitoring of the settling
pond discharge into this projected spawning region is highly recommended.
29
-------
TABLE 7. LEVELS OF POSSIBLE TOXICANTS IN WATERS OF THE WEST DECKER MINE SETTLING POND SYSTEM^ (RESULTS OF POND SAMPLES REPRESENT MEANS OF VALUES
1 RECORDED FOR TWO OR MORE LOCATIONS WITHIN THE POND)
Site and date
of sample
collection
Pond
7-27-76
8-24-76
9-19-76
10-21-76
11-18-76
12-14-76
1-12-77
2-09-77
4-06-77
Influent
7-27-76
8-24-76
9-19-76
10-21-76
4-06-77
Effluent
7-27-76
8-24-76
9-19-76
10-21-76
4-06-77
uo/liter Recomnieiic'at'ons uS/tlter Recommend»t1ons ua/?1ter
0
0
0
0
0
0
0
0
0
0
0
0
<0
0
0
0
0
0
.81
.3#
.38
.17
.09
.28
.26
.24
.27
.85
.55
.11
.0&
.58
.87
.42
.42
.11
0.38
Should not 1
exceed 0.05 2
ug/Hter^ 1
1
1
1
1
1
1
1
3
3
1
1
1
1
1
1
.4 Data not
. 1 sufficient for
.4 aquatic life
.7
.8 Should not
.2 exceed 50
. 1 ug/Hter for
.2 other purposes-
.2
.6
.7
.3
.5
.6
.3
.9
.2
.9
1.1
0
0
<0
0
1
2
2
2
0
0
0
<0
<0
<0
0
0
<0
0
0.
.5
.5
.3
.4
.4
.3
.2
.6
.3
.4
.6
.3
.3
.3
.4
.4
.3
.5
5
! Recommendations
Should not
exceed 0.01 of
the 96-hour LC50
as determined
through bioassay
using a sensi-
tive resident
species-
Should not
exceed 10.0
ug/liter for ,
other purposes-
mg/mer Recommendations
<0.001 Should not
<0.002 exceed 12.0
<0.005 ug/llter^
<0.005
<0
<0
<0
<0
<0
<0
<0
<0
<0
<0
<0
<0
<0
.005
.005
.005
.005
.005
.001
.002
.005
.005
.005
.001
.002
.005
•g/littr ^commendations
<0.01 Should not
<0.01 exceed 0.01
<0.1 times the 96-
<0.1 hour LC50-/
<0.1
<0.1 Should not
<0.2 exceed SO-/
<0. 1 pg/liter for
<0.1 other purposes
<0.01
<0.01
<0.1
<0.1
<0.1
<0.01
<0.01
<0.1
<0.005 <0.1
<0.
005
<0.1
- Approximate values (for example, < a certain number) could not be averaged; however, estimations for different sites within the pond were always
recorded as < the same value on any one sampling date.
-Spuriously high value of 90 ug/liter disregarded in calculation of mean.
- Taken from well whose water was source of influent.
-''For freshwater aquatic life and wildlife (U.S. Environmental Protection Agency 1977a).
-For domestic water supply (U.S. Environmental Protection Agency 1977a).
-------
Sediment Chemistry
Elemental analyses performed by the Montana State Board of Health on
sediment samples obtained from the settling pond are presented in Table 8.
Values are similar for the different locations and sampling dates. Although
it is not possible from such a limited number of samples to make detailed
comments on these results, several elements, especially boron, iron, and
aluminum, were present in relatively high concentrations. The settling pond
may be acting as a trap or sink for some elements; this subject is discussed
more fully in the bacteriology section on sulfate reduction.
ALGAL PRODUCTIVITY
Data on all estimations of algal productivity are included in the
Appendix, Tables A-10 through A-13.
Productivity Estimates
When ice cover and high loading of suspended particulates were absent,
the settling pond was sufficiently shallow to allow light penetration
throughout the water column. The construction of diurnal oxygen curves
indicated that gross primary productivity of the settling pond community
averaged 6.88 grams of oxygen per square meter per day for July through
September 1976. Welch (1968) recorded an annual average very similar to
this for a small, fertile farm pond in Georgia. Our estimates of gross
primary productivity for the summer months (July through September 1976)
ranged from 4.57 to 8.44 grams of oxygen per square meter per day; these
values are within the ranges Odum and Hoskin (1958) gave for systems with
both plankton and bottom mud components and systems with dominant bottom
plant and animal communities and less important planktonic components.
Estimates of pond metabolism for October through December 1976 were very
low, and no net primary productivity occurred. These observations were the
result of decreasing metabolic activity with lower water temperatures as
well as high turbidity and ice cover reducing the amount of light available
for photosynthesis.
Productivity data from labeled carbon uptake experiments indicated that
fixation of inorganic carbon in the water column was generally low from July
through December 1976, ranging from 0 to 0.12 g carbon fixed per square
meter per day. Wetzel (1975) presented comparative rates of phytoplankton
primary productivity in selected fresh waters of different fertilities. The
range of the limited number of measurements performed as part of the present
study was similar to ranges in the productivity values reported by Wetzel
for oligotrophic waters.
A direct comparison of planktonic and community primary productivity
was not possible. Both gross and net values may be calculated from diurnal
oxygen data while values somewhere between gross and net results from
carbon-14 fixation measurements. However, in comparison to values reported
in the literature for both diurnal oxygen and carbon-14 estimates of primary
productivity, community productivity was moderate and planktonic productivity
31
-------
TABLE 8. ELEMENTAL ANALYSES OF SEDIMENT SAMPLES COLLECTED AT THE
WEST DECKER MINE SETTLING POND (CONCENTRATIONS ARE GIVEN
IN ug PER GRAM OF SEDIMENT)
Parameter
Arsenic
Lead
Lithium
Zinc
Manganese
Stronti urn
Boron
Aluminum
Cadmi urn
Copper
Iron
Selenium
Mercury
North End
(12/16/76)
0.025
<0.05
0.25
0.84
4.0
1.1
100
292
<0.001
0.35
225
0.005
0.0005
Sample Location
South End
(8/24/76)
0.059
<0.05
0.29
0.6
4.3
1.7
64
310
0.003
0.34
240
0.007
0.001
South End
(12/16/76)
0.001
<0.05
0.28
0.89
4.3
L.4
71
345
0.003
0.28
251
0.008
0.0002
was low during the summer. Indirectly, it appeared that the major contribu-
tion of primary production was from benthic populations which probably
included plankton that had settled out.
Chlorophyll Measurements
Chlorophyll a measurements were made on water samples obtained from the
settling pond to provide monthly estimates of phytoplankton standing crop.
Pigment concentrations, calculated by the monochromatic method, were rela-
tively low within the water column during the summer (0 to 1.20 mg per cubic
meter), higher during the autumn (3.16 to 6.78 mg per cubic meter), and
markedly higher during the"winter (35.82 to 521.18 mg per cubic meter).
These values were not averaged because of significant month to month
32
-------
variation. Explanations may be advanced for the increase in autumnal stand-
ing crop although these considerations are somewhat in contradiction to the
results of diurnal oxygen measurements. Garrison (P. J. Garrison, Montana
State University, personal communication) suggested that stagnation of the
pond may have allowed phytoplankton populations, normally flushed out in the
effluent, to increase substantially within the water column.
The extremely high pigment concentrations recorded from the January and
February samples remain unexplained. High phytoplankton standing crop is
usually accompanied with oxygen production due to photosynthesis. Although
oxygen concentrations within the pond were low (1.3 to 2.2 mg per liter) and
the thick ice cover prevented solar radiation from penetrating into the pond
waters, pigment concentrations were considerably higher than in the summer
and autumn samples. Attempts made to correlate levels of chlorophyll a with
those of inorganic nitrogen (which were also higher in the November through
February pond samples) were unsuccessful. Cell counts and volumes would be
helpful in interpreting these data, but are not currently available. Produc-
tivity measurements were not performed during these two months; carbon-14
uptake rates would have provided corroborative data on the phytoplankton
populations.
Artificial substrate (glass slides) were placed in the settling pond
effluent (below the flume) to sample periphyton. The slides were allowed to
incubate approximately one month before periphytic populations were removed
for estimations of biomass and the concentration of chlorophyll a. Average
rates of bioaccumulation were 100.2, 300.5, and 17.2 mg of carbon per square
meter per day for the May-June 1976, June-July 1976, and July-August 1976
incubation periods, respectively. These values, when compared to those from
a variety of habitats given in Stockner and Shortreed (1976) would be con-
sidered relatively low. The May-June interval showed higher chlorophyll a
values relative to the amount of bioaccumulation, indicating that popula-
tions of photosynthetic organisms were higher at this time. Very little
periphyton development was noted during the autumn and winter, probably as a
result of discontinuous to nonexistent discharge from the pond, and lower
water temperatures.
A periphyton sampler, similar to the one for the effluent, was placed
within the settling pond near the standpipe. Data were obtained for the
September-October 1976 incubation period only; the average rate of bio-
accumulation was 439.0 mg of carbon per square meter per day, and average
chlorophyll a concentration was 24.7 mg per square meter.
Algal Bioassays
In the Algal Assay Procedure: Bottle Test performed on samples of
settling pond water, there was a tendency for both nitrogen and phosphorus
limitation. This observation was most prominent in test waters collected
from November 1975 to September 1976. Pond samples collected in October and
November 1976 were phosphorus limited for the growth of the test alga.
Chemical assessment of the sample waters supported this finding; orthophos-
phate-phosphorus ranged from 0.001 to 0.010 mg per liter and total phosphorus
from 0.012 to 0.013 mg per liter. Nitrogen levels during these months,
33
-------
particularly November, were high, probably as a result of overburden blast-
ing and increased mining activities in the vicinity of the pond. Phosphorus
limitation was not surprising considering the findings of Chiaudani and
Vighi (1976). These researchers observed nitrogen limitation of the growth
of Selenastrum capricornutum only when N:P ratios in the culture medium were
6 or less.fin N:P ratio of 8 or greater resulted in phosphorus limitation.
In the settling pond, the autumn and winter nitrogen levels exceeded those
of phosphorus by two orders of magnitude and algal growth was phosphorus
limited.
Stimulation of algal growth with the EDTA spike was rarely observed,
indicating that either micronutrients were not limiting or toxic concentra-
tions of elements, capable of being chelated, were not present.
BACTERIOLOGY
Estimation of Selected Bacterial Populations
Most probable number results for organisms potentially functional in
the nitrogen cycle are given in Table 9 as ranges in the order of magnitude
of these determinations. No seasonal trends were evident in the distribu-
tion of these data. The ratio of dry weight to wet weight was computed for
each sediment sample that was diluted and inoculated into MPN tubes as a
check on the moisture content of samples collected at different times.
TABLE 9. MOST PROBABLE NUMBER (MPN) ESTIMATIONS OF ORGANISMS POTENTIALLY
FUNCTIONAL IN THE NITROGEN CYCLE OF SEDIMENT SAMPLES TAKEN FROM
THE WEST DECKER MINE SETTLING POND
Number of organisms
Number of MPN per 100 grams (wet
Physiological process estimations weight) of sediment
Mine sump Settling pond
Ammonifi cation
Nitrification, Step 1
Nitrification, Step 2
Denitrifi cation
Nitrogen fixation
7
7
7
7
4
106-109
105-108
4 6
c p
10b-10B
102-104
106-109
105-108
4 7
10 -10'
5 8
101 -104
(Azotobacter)
34
-------
It is difficult to judge whether the numbers of organisms detected in
sediment samples from the West Decker Mine settling pond were high relative
to counts of similar groups of bacteria recovered elsewhere. Comparisons
between our study and the limited number of similar studies found in the
literature should be made with caution because of differences in methods of
collection and treatment of sediment samples. In general, however, our MPN
estimations of bacteria potentially functional in the nitrogen cycles ex-
ceeded those of similar groups of bacteria in Lake Erie sediments (Dutka et
al_. 1974). Most probable numbers of nitrifying bacteria in New Jersey river
sediments (Matulewich et aj. 1975) were also somewhat lower than those ob-
tained from samples talcen at the West Decker Mine.
Plate counts of aerobic heterotrophic bacteria present in the settling
pond sediments estimated their populations to range from 106 to 108 colony-
forming units per gram (dry weight) of sediment. Again, it is difficult to
compare these results with those of other investigators because sample
treatment itself may account for differences of two orders of magnitude.
However, densities of aerobic heterotrophs in the settling pond sediment
samples were approximately 100 times greater than those in Tongue River
sediments which were sampled concurrently. According to chemical analysis
of both types of sediment, the pond samples were higher in organic carbon
and, consequently, in substrates for these organisms. Higher organic carbon
may be due to the influence of coal residues.
The organisms potentially functional in the sulfur cycle have been the
most intensively studied in the West Decker Mine settling pond. There is a
biogeochemical cycle of sulfur (Figure 5), and areas where coal mining has
occurred provide a natural environment for sulfur bacteria (Lundgren et al_.
1970). Microorganisms are particularly important in the mediation of reac-
tions within the sulfur cycle. Sulfur can exist in six oxidation states,
but usually sulfate, elemental sulfur, sulfide, and organic sulfur (shown
encircled in Figure 5) are of importance in nature. In brief, the sulfur
cycle involves: (1) the oxidation of reduced inorganic sulfur compounds,
(2) the reduction of sulfate to sulfide, (3) the assimilation of both re-
duced and oxidized forms of sulfur by organisms for biosynthesis and other
metabolic functions, and (4) the decomposition of organic sulfur-containing
substances. The contributions of sulfur cycle organisms to acid mine drain-
age problems have been studied (Lundgren et al. 1972; Dugan 1972) in the
East and Midwest, but little is known about tfieir activity in alkaline
situations such as those characterizing most coal mines in the western
states. Data on the relative abundances of different groups of sulfur
cycle bacteria in water samples from a variety of sites and sediments,
primarily from the settling pond, are presented in Table 10. One of the
most important findings in these data was the relatively high populations
of acidophilic iron oxidizing bacteria in the water and sediments, and
acidophilic sulfur oxidizing bacteria in the sediments. It is possible
that T. ferrooxidans is responsible for at least part of the MPN values
reported for acidophilic sulfur oxidizers, since sulfur can serve as an
energy source for this organism. Both types of bacteria are characteristic
of acid mine drainage; however, acidic conditions have never been reported
at West Decker. The presence of T._ ferrooxidans in mine waters and
35
-------
OXIDATION
REDUCTION
METHYLATION
plants, microorgani
PRECIPITATION
MX-
OXIDATION
Thiobacillus
DISSIMILATION
Desulfovibrio
Des ulfa. tomacul urn
OXIDATION
thiobacilli,
colorless, green
and purple
sulfur bacteria
blue green
algae & others
ASSIMILATION
plants, algae,
acteria, yeasts
SPONTANEOUS
CHEMICAL
OXIDATION
DECOMPOSITION
mixed
mechanisms
CHEMICAL REACTIONS
WITH METALS
PUTREFACTION
heterotroohic
bacteria
DECOMPOSITION
METKYLATION
Pseudomonas
Achromobacter
Flavobacteri
hydrotroilite
N^
BIOSYNTHESIS
plants, algae
bacteria
UPTAKE ^ ,
rganic
S
metal sulfides
organic
S
in detrital
material
some aerobic
bacteria and
fungi
in living
organisms
pyrite, marcasite
OXIDATION
Thiohacillus
Figure 5. The biological sulfur cycle.
36
-------
CO
TABLE 10. MOST PROBABLE NUMBER (MPN) ESTIMATIONS OF ORGANISMS POTENTIALLY FUNCTIONAL IN THE SULFUR CYCLED
A. Samples taken from various locations
Location
Settling pond
influent waters
(Site 1)
Settling pond
effluent waters
(Site 6)
Settling pond
surface water
(site 3)
Test pit .water
Stock well water
east of mine
Tongue River
Date
9-21-76
10-21-76
4-05-77
9-21-76
10-21-76
11-18-76
12-16-76
1-13-77
2-11-77
4-05-77
11-18-76
1-13-77
2-11-77
12-16-76
Sulfate reduction
>2.4 x 104
3.5 x 104
n
1.6 x 10*
>2.4 x 104
3.3 x 103
1.1 x 103
3.5 x 103 £/
»\
5.4 x IQ6
7.9 x 102
2.3 x 10*
7.9 x 102
—
1.7 x 103
1.3 x 102
2.0 x 101
Sulfur oxidation
(pH 2.5)
2.1 x 103
7.0 x 103
4.9 x 102
0
0
0
4.0 x 101
0
0
0
0
0
2.0 x 101
0
0
Iron oxidation
(pH 2.5)
>2.4 x 104
3.5 x IQ4
1.6 x 104
2.2 x 103
0
4.9 x IQ2
5.4 x 103
7.0 x 101
5.0 x 101
0
2.4 x 103
3.3 x 103
7.0 x 101
2.0 x 101
0
Thiosulfate oxidation
(pH 7.5)
5.4 x 103
3.5 x 104
2.2 x 102
2.6 x 102
1.1 x 104
>2.4 x 104
1.6 x 104
9.2 x 103
4.9 x 102
2.4 x lo1
3.3 x 102
4.6 x 103
3.3 x 102
4.9 x 102
0
Reservoir water
Tongue River
Reservoir
sediment
12-16-76
1.3 x 10'
-------
TABLE 10. (Continued)
B. Sediment samples taken at Site 3
CO
00
Date
1-14-76
2-20-76
4-20-76
5-20-76
6-29-76
8-19-76 I?
9-21-76
10-21-76
11-18-76
12-16-76
1-13-77
2-11-77
4-05-77
Sulfate reduction
5.4 x 106
5.4 x 106 &
2.4 x 106
8.0 x 104
4. 9 x 106
2.3 x 106
1. 1 x 106
3.3 x 105 $f
>2.4 x 106
4.9 x 106
6.3 x 106
3.5 x 107
1.3 x 106
..
1.3 x*106
Sulfur oxidation
(pH 2.5)
8.0 x 103
1.3 x 104
2.3 x 104
3.3 x 104
2.3 x 104
1.1 x 105
—
--
4.0 x 103
3.3 x 104
2.3 x 104
1.7 x 104
7.9 x 104
3.3 x 104
2.4 x 105
Iron oxidation Thiosulfate oxidation
(pH 2.5) (pH 7.5)
2.3 x 104
3.3 x 104
7.0 x 104
3.3 x 104
1.7 x 105
1.3 x 105
—
—
4.0 x 103
1.7 x 105
3.4 x 104
6.3 x 104
4.9 x 105
3.1 x 104
—
—
'
—
--
--
--
—
--
9.2 x 106
5.4 x 106
1.4 x 106
1.4 x 106
2.2 x 106
4.3 x 105
7.9 x 104
Dry weight /
conversion-
18.32
27.32
12.33
31.75
38.31
33.00
5.08
1.18
27.61
29.78
37.34
26.00
30.09
36.88
45.52
-Results are expressed as the number of organisms per 100 ml of water or 100 g (wet weight).
-Duplicate determinations.
-lumbers are grams dry weight per 100 g wet weight (January-August 1976) or 100 ml (September 1976-April
1977) of sediment.
-^Values are for sediment diluted 1:1 with sterile distilled water.
P/
-Sample taken at Site 2.
-------
sediments indicates that they have oxidized pyrite to acid, the relative
numbers of organisms correlating with the amounts of pyrite oxidized (Ougan
1972).
Our data show numbers of T. ferrooxidans comparable to those of an acid
mine drainage stream described by Tuttle et al_. (1969); thus, there is a
high level of pyrite oxidizing activity in water and sediments associated
with the West Decker Mine. Unlike results at Decker, Johnson and Bromel
(1977) reported very low or non-detectable numbers of iron oxidizing bacteria
in sediment samples obtained from impoundments at two coal mines and from
flowing waters in the Knife River Basin of North Dakota. Surface waters
associated with the Belle Ayr Mine near Gillette, Wyoming, contained higher
numbers of sulfur oxidizing bacteria than those in the West Decker samples
(John Adams, Department of Microbiology and Veterinary Science, University
of Wyoming, personal communication). Numbers of sulfate reducing bacteria
detected either in sediments (North Dakota) or in surface water (Wyoming)
were similar to estimations of the abundance of this group of bacteria in
West Decker samples.
On one occasion (March 1977) the acid mine streams near Sand Coulee,
Cascade County, Montana were sampled. A description of this area is given
in McArthur (1970). Samples collected from two sites along No Name Creek
(Bar Z Ranch and across from the Sand Coulee Fire Department) yielded 1.7 x
104 and 4.9 x 103 sulfur oxidizing bacteria per 100 ml of sample water,
respectively. Iron oxidizing bacteria at both sites exceeded 2.4 x 10s
organisms per 100 ml of water. Concentrations of ferrous iron and sulfate
ranged from 310-563 mg/liter and 5,050-15,000 mg/liter; pH values ranged
from 2.7-2.8. These conditions resembled those of acid drainages associated
with coal mining practices in the eastern and midwestern states, and
provided a sharp contrast to the visible nature and chemical composition of
West Decker Mine waters.
Enrichment of Selected Bacterial Populations
Acidophilic iron oxidizing bacteria were not isolated from the West
Decker Dietz-1 and Dietz-2 coal samples that were analyzed. These organisms
may be found within microzones in the coal or overburden where the existence
of oxidizable sources of iron and sulfur are likely. Acidophilic iron
oxidizing bacteria were isolated from the exposed coal seam wall near West
Decker's sump pond. Pyritic materials in overburden and coal, once exposed
to air, will spontaneously oxidize. Regions of low pH, resulting from these
localized oxidations, present favorable growth conditions for acidophilic
thiobacilli.
Enrichment for iron and sulfur oxidizing bacteria in the variety of
locations described in Section V was successfully accomplished. Acidophilic
iron oxidizing bacteria (probably T. ferrooxidans) were detected at all
locations. It appears that these organisms are much more ubiquitous than
previously thought. According to Starkey (1966) acidophilic thiobacilli are
not isolated from non-acidic environments. It therefore seems unlikely that
the environment in which these organisms were detected would be favorable
for their growth; the results reported in the next section have some bearing
39
-------
upon this. Acidophilic iron and sulfur oxidizing bacteria were originally
considered to be associated with areas where mining operations were proceed-
ing, and that it was possible that the effluent from the settling pond was
acting as one source of these organisms in the Tongue River flood plain.
Their presence in the Tongue River sediments upstream from the West Decker
Mine may be due to discharges from other mining operations.
Growth and Survival of Acidophilic Iron Oxidizing Bacteria
Growth curves of the two organisms, TF-1 and TF-2, isolated and puri-
fied on ISP medium, are shown in Figure 6. These curves compare very favor-
ably to one of T. ferrooxidans given in Silverman and Lundgren (1959).
Because these isolates were capable of growth in an inorganic medium
(9K salts) supplemented with either ferrous iron or elemental sulfur, and
showed similarities to previously studied organisms, they appeared to be
typical strains of T. ferrooxidans.
Survival of isolates TF-1 and TF-2 in sterile settling pond water is
shown in Table 11. These organisms did not survive well in mine water. The
presence of acidophilic iron oxidizing bacteria in the waters of the West
Decker Mine settling pond may be due to a continuous input in the influent
waters; however, they were still detected in the water column when there was
no influent. The survival of bacteria in sediments has been documented
(Hendricks 1971; Kaneko and Colwell 1973; Van Donsel and Geldreich 1971)
and, considering how widely these organisms were distributed in sediments of
the Tongue River flood plain, long term survival therein seems likely. It
is possible that upwelling from the sediments could have redistributed these
organisms in the water column of the pond.
TABLE 11. SURVIVAL OF TWO ACIDOPHILIC IRON OXIDIZING ISOLATES,
TF-1 AND TF-2, IN STERILE SETTLING POND
Organism
TF-1
TF-2
Initial MPN/100 ml
1.6 x 106
2.4 x 106
>2.4 x 108
1 hr 3 hr 17 hr 24 hr
o
0
>2.4 x 108 1.6 x 108 1.4 x 105 4.9 x 103
- Viable organisms were determined by the MPN technique.
40
-------
8.5
8.0
7.5
E
*x
CO
UJ
o
o
o
7.0
6.5
TF-2
CELL NUMBER
10 20 30 40
TIME (HOURS)
50
4.0
CONCENTRATION Fe"*"*4 O—O
60
3.5
Q.
O.
O
O
3.0
2.5
70
Figure 6. Growth curve of two isolates tentatively identified as
Thiobacillus ferrooxidans, TF-1 and TF-2.
41
-------
Leaching Experiments with Thiobaoillus ferrooxidans
Results of leaching experiments presented in Table 12 indicate that
little pyrite was available for microbial oxidation. The first and second
sets of experimental flasks showed insignificant differences between the pH
values and titratable acidity of untreated samples and controls (sodium
azide added to inhibit biological activity). A decrease in pH values was
more significant in the third set of flasks compared to controls. Iron,
added to serve as an energy source, appeared to promote the biological pro-
duction of acid. It was impossible to measure titratable acidity of this
set of flasks because the addition of base spontaneously oxidized the fer-
rous iron. Suspended ferric iron interfered with end-point detection of the
titration. This experiment, and the one attempting to enrich for growth of
acidophilic iron oxidizing bacteria in coal samples from Decker, indicated
that the energy sources in coal may be non-uniform; that is, may be located
in specific microzones.
Microzonal activity could have been of significance in connection with
the analyses of coal by Chadwick et al. (1975) for sulfur and trace elements
in the Rosebud and McKay coal seams Tpart of the Fort Union formation) near
Colstrip. These analyses indicated that sulfur and the heavy metals:
antimony, arsenic, beryllium, cadmium, mercury, nickel, and selenium are
"markedly enriched" at the base of the coal seams. Chromium, copper,
germanium, and zinc also showed concentration tendencies in some of the
test cores. These metals may also occur as inclusions, intergrowths, or
replacement bodies in pyrite (Chadwick et al. 1975), perhaps subjecting
them to direct microbial attack. Pockets oT pyrite or other metal sulfides
in the coal could create microzones of acid production by thiobacilli,
resulting in solubilization of heavy metals. Although analyses of this
type have not been carried out on Decker coal, the possibility of a similar
situation exists.
Similar leaching experiments with Decker overburden were not performed
in the present study. The potential importance of pyritic materials in the
overburden when compared to amounts present in the coal itself is recognized.
Perhaps the difficulty in demonstrating acid production from T. ferrooxidans
incubated in coal further demonstrates the possible significance of pyritic
materials in the overburden.
Physiological Studies of Thiobacillus ferrooxidans Using Respirometry
Respirometric experiments were undertaken to characterize optimum growth
conditions of our isolates from the West Decker Mine which were tentatively
identified as T. ferrooxidans. The results, presented in Table 13, indicated
that the isolates TF-1 and TF-2 resembled T. ferrooxidans in their preference
for iron as an energy source at low pH. Only marginal activity was noted
with reduced sulfur compounds at low pH, and virtually no respiration was
measured at pH values corresponding to West Decker Mine water environments
(pH 8). T. ferrooxidans is capable of oxidizing reduced sulfur compounds
but sometimes requires a considerable adaptation period in order to do so
(Tuovinen and Kelley 1972). Our data strongly suggested that these isolates
were typical T. ferrooxidans, capable of growth only at low pH. Their
42
-------
TABLE 12. INCUBATION OF THIOBACILLUS FERROOXIDANS WITH COAL
•£»
00
Initial
Set
1.
2.
3.
Treatment
None
Sodium
azide
None
Sodium
azide
Iron
Iron +
sodium
azide
7.
7.
4.
4.
3.
3.
PH
09 ±
21 ±
47 ±
45 ±
77 ±
93 ±
Acidity
(mg/liter CaC03)
0.26
0.27
0.09
0.20
0.07
0.08
249 ±6 6.
221 ± 15 6.
397 ± 37 5.
422 ± 61 5.
2.
2.
PH
09
42
32
38
24
86
± 0.
± 0.
± 0.
± 0.
± 0.
± 0.
33
Days
Net change
Acidity Acidity
(mg/liter CaC03) pH (mg/liter CaC03)
03
12
10
03
13
08
336 ± 69 -1.
307 ± 136 -0.
425 ±65 +0.
411 ±86 +0.
-1.
-1.
00
79
85
93
53
07
+87
+86
+28
-11
--
—
-------
TABLE 13. RESULTS OF RESPIROMETRY STUDIES ON TWO ISOLATES OF
THIOBACILLUS FERROOXIDANS
02 taken up - h"1 • (SxlO9)"1 cells
Energy source
r- ++
Fe
Fe + glucose-yeast extract
glucose-yeast extract
pH
3
3
3
TFi
1238
1668
1.2
TF2
1441
1455
1.1
S203
S203
S°
S°
S°
5
8
3
5
8
3.4
2.0
13.6
12.8
0.4
3.4
1.3
6.2
20.9
5.3
presence in the West Decker Mine was possibly due to their activity in low
pH microzones somewhere in the coal-bearing strata.
Sulfate Reduction in Pond Sediments
The detection of sulfide in water and sediment samples of the settling
pond system and in groundwaters from a limited number of wells in areas
adjacent to the mine prompted a study of sulfate reduction by bacteria.
Sulfate reducing bacteria are responsible for the generation of hydrogen
sulfide in environments conducive to their growth. In addition to certain
ranges of temperature and pH values, these bacteria require simple organic
compounds or hydrogen as sources of energy, inorganic nutrients, and reduc-
ing conditions (Eh = -0.2V). Sulfate is also required, not only for assimi-
lation as a nutrient, but because it acts as the terminal electron acceptor
for respiration. Dissimilatory (or respiratory) sulfate reduction results
in the production of hydrogen sulfide which has extensive industrial,
economic, and ecological effects (Postgate 1965). Consequently, a voluminous
amount of literature, ranging from technical reports to complete academic
treatises, exists on these organisms (see reviews - Postgate 1959, 1960, and
1965).
Results of the in situ measurements of sulfate reduction in sediment
samples of the West Decker Mine settling pond are presented in Table 14.
44
-------
TABLE 14. RESULTS OF IN SITU MEASUREMENTS OF SULFATE REDUCTION IN SEDIMENTS OF THE WEST DECKER MINE SETTLING POND
en
Dates Location _ Dry weight of H 35,n . . . 35c n. Rate of
experiment within . Duration S04" Concn Temp 1.0 ml sediment "2 b°4 input Cd s traPPed, sulfate reduction h/
initiated pond Treatment (h) (mg/liter) °C (g) (cpm/liter) (cpra/liter)-' (mg H2S/liter sediment/day)-
September 1976
Octobe.r 1976
December 1976
^September, 40%
Site 2
Site 3
Site 3
Site 3
Site 3
Site 3
counts
-Calculated bv method
None 48 150 16.2 0.288 3.03 x 107 4.84 x 105
None 48 150 17.1 0.264 3.03 x 107 1.52 x 106
None 43.5 180 6.1 0.298 2.93xl07 2.92xl06
Lactate 43.5 180 6.1 0.298 2.93 x 107 9.68 x io6
spiked
(300 mg/liter)
None 145.5 44 1.0 0.443 6.25 x IO6 1.49 x IO6
Lactate - - -- -- 5.64 x IO6 1.12 x io6
spiked
(300 mg/liter)
recovered; October and December, >70% counts recovered.
-, -, (Concentration S04) (Radioactivity H235S) (24 h) (1.06)
of Ivanov (19641: ma HoS/lit.pr Vriav *• = - , - - -
1.27
3.98
10.50
34.85
1.83
1.54
(Radioactivity H23SS04) (Duration of experiment)
-------
Two locations in the pond were compared in September 1976. Surface sediment
at the southern end (Site 3) had a higher rate of bacterial dissimilatory
sulfate reduction than that at the northern end (Site 2). All subsequent
rate determinations were conducted on samples from the southern end.
Because sulfate reducing bacteria require organic materials for growth,
insufficient amounts of these substances limit the process of sulfate reduc-
tion. In October and December 1976, experiments were undertaken to test
possible carbon limitation in the West Decker settling pond sediments. In
the October experiment, addition of a lactate spike (a readily utilizable
energy source) of 300 mg/liter resulted in a greater than threefold increase
in the rate of sulfate reduction. This stimulation, due to the presence of
excess carbonaceous substrate, was not observed in December because another
factor, possibly temperature, limited the bacterial reduction of sulfate.
Few direct investigations of rates of sulfate reduction appear in the
literature (Trudinger et aJL 1972). Sand et al. (1975) developed a radio-
isotope assay for estimating populations o?~suTfate reducing bacteria in
water and sediments sampled in the vicinity of a pulp mill effluent. The
technique measured sulfate reduction indirectly, that is, by the disappear-
ance of radioactive sulfate rather than the appearance of labeled hydrogen
sulfide. Chebotarey (1974), using an isotope method similar to ours to
evaluate the bacterial production of hydrogen sulfide in two karst lakes,
considered rates of 6.2 and 13.3 mg H2S per kilogram of sediment per day to
be quite vigorous. October 1976 rates exceeded those reported by Chebotarev,
indicating that relatively high rates of sulfate reduction were occurring
in the sediments of the West Decker settling pond and, consequently, large
amounts of hydrogen sulfide were being generated.
The liberation of hydrogen sulfide has major ecological consequences;
however, only those pertaining to water quality alterations will be dis-
cussed. The sulfide ion, produced by the dissociation of hydrogen sulfide,
reacts with heavy metals and other elements to form insoluble sulfide
minerals; possible toxicants are thereby effectively removed from solution.
In laboratory experiments, Miller (1950) demonstrated the formation of the
sulfides of antimony, bismuth, cobalt, cadmium, iron, lead, nickel, and
zinc as a- result of the activities of Desulfovibrio desulfuricans, which
is the most common and best known species of sulfate reducing bacteria.
Laboratory experiments by Baas Becking and Moore (1961) showed that a
variety of metal sulfide minerals could be formed by sulfate reduction.
Tuttle et aJL (1969) showed that a wood dust dam containing an active popu-
lation of sulfate reducing bacteria increased the pH value of acid mine
waters coming into contact with it. In addition, the precipitation of
iron (as ferrous sulfide) was promoted.
To test whether the West Decker Mine settling pond was acting as a
trap for heavy metals, settling pond sediments were analyzed using the pro-
cedures of Vasudevamurthy et al. (1956). We extracted 2.13 mg of metal
bound sulfides per g (dry weigfit) of settling pond sediment. Sorokin (1968)
felt that sulfides in concentrations of 410 to 4520 mg per liter of sediment
(making up as much as 1% of the dry weight of the sediment) were "enormous"
quantities. Thus, the prbcess of bacterial dissimilatory sulfate reduction
appears to be important in the precipitation of metals in mine waters flow-
ing into the pond before their discharge into the Tongue River flood plain.
46
-------
SECTION VII
SUMMARY
The study described herein was designed to elucidate the function of
a surface coal mine settling pond in altering water quality. Although three
approaches to this investigation were attemped, the erratic operation of the
pond during the course of this study limited how completely these approaches
could be undertaken. Nonetheless, certain conclusions and tentative recom-
mendations can be made. Clearly, the mine drainage waters underwent altera-
tions within the settling pond. It is important that the settling pond
system be maintained and improved so that the effluent from the mine can
be nonhazardous to the receiving environment and can serve useful purposes.
CONCLUSIONS
(1) Influent water was not continually supplied to the pond. When it
was, however, effluent was discharged into the Tongue River flood plain.
Although concentrations of total dissolved solids, bicarbonate, sodium,
sulfate, and nitrogen species were higher in the discharge water than in
the Tongue River, the quality of the effluent was sufficient to meet Montana
state-imposed criteria for discharge water from a surface coal mine.
(2) This study supported the findings of Whalen and Leathe (1976)
that, under the conditions operable during the course of this investigation,
West Decker Mine produced no measurable impact upon the Tongue River or
Tongue River Reservoir. However, coal mining in the West Decker area may
be impacting groundwater quality since the settling pond water, considered
"altered groundwater," differed chemically from surrounding groundwaters.
In ionic composition, pond water was intermediate between the local ground-
water and the surface waters of the nearby Tongue River and Tongue River
Reservoir.
(3) The West Decker Mine settling pond provided a unique opportunity
to study the microbial sulfur cycle. One of the most significant observa-
tions to emerge was the consistent detection of the bacterium Thiobacillus
ferrooxidans. Cultures of this organism were physiological ^similar to
those associated with acid drainage problems in eastern and midwestern coal
mining regions. Acidic conditions, however, were not observed within the
pond waters or drainage waters pumped into the West Decker Mine settling
pond. This is attributable to the high buffering capacity of waters in this
region. It was difficult to demonstrate acid production in the laboratory
using samples of West Decker Mine coal. T. ferrooxidans may be restricted
to pyrite-containing microzones in the overburden and coal strata. It is
47
-------
possible that either this organism entered the pond via drainage waters and
survived in the sediments, or that it is much more ubiquitous than previously
reported in the literature.
(4) Other sulfur cycle bacteria are also important from a water quality
standpoint. The relatively high numbers and activity measurements of sulfate
reducing bacteria, as well as the significant amount of metal-bound sulfides
in the settling pond sediments, make a strong case for the contributions of
these organisms toward precipitation of toxic metals.
(5) The settling pond water was sampled on nine occasions for mercury,
arsenic, selenium, lead, and cadmium. Recommended limits for aquatic life
have not been firmly established for all of these potentially toxic elements,
but of those that have been, only mercury exceeded the acceptable level.
Average mercury concentrations in settling pond samples ranged from 0.09 to
0.81 ug per liter, which are considerably higher than that recommended for
freshwater aquatic life and wildlife (0.05 ug/liter) by the U.S. Environ-
mental Protection Agency (1977a).
(6) Blasting of mine overburden with ammonium nitrate explosives, and
input of explosives in runoff from storage vats adjacent to the pond,
periodically enriched the pond with nitrogen.
(7) Values for the sodium absorption ratio (SAR) calculated from
chemical data of water samples collected from the West Decker Mine settling
pond averaged below 8, in contrast to reports of relatively high ratios for
groundwaters in the Decker area. The average SAR of pond water was not
ideal for irrigation of mine spoil reclamation sites but would not cause
adverse effects to vegetation and soil structure if sufficiently diluted.
(8) Instability of the settling pond limited the value of primary pro-
ductivity measurements made from July to December 1976; data were insuffi-
cient to assess the trophic status of the pond. The major primary producers
appeared to be benthic algal populations in summer 1976. The pond showed a
potential for moderate productivity which probably was important in water
quality improvements such as removal of inorganic nitrogen in the water
column and oxidation of sulfide contributed by the influent.
(9) Algal bioassays indicated that the settling pond water was nutri-
ent limited. Phosphorus limitation was observed in pond samples collected
in autumn 1976 when concentrations of nitrogen were particularly high.
Laboratory bioassays did not show inhibition of the test alga by heavy
metals in these waters.
RECOMMENDATIONS
(1) Convenience, rather than careful planning, has been the major
consideration in the design and operation of West Decker's settling pond.
Hill (1976) has recently reviewed aspects of the physical function and
design of surface mine sedimentation ponds. His discussion of design con-
siderations such as "(1) capacity and size to meet water quality criteria,
48
-------
(2) storage volume, (3) number of ponds, (4) location of pond, (5) shape of
pond, (6) inlet design, (7) outlet design, (8) cleanout procedures, and (9)
close down" would be helpful in improvement of the present operation at the
West Decker Mine or in the initial design of sedimentation basins for Decker
Coal Company's future mines.
(2) A two-pond system may be more efficient for improving water
quality. A deeper primary pond could serve two purposes, one of which would
be to facilitate sedimentation since it would be less subject to wind-driven
mixing. Zones of anaerobiosis could develop in deeper waters and promote
bacterial sulfate reduction which would remove heavy metals and other
elements from solution. Design considerations should be such that adequate
contact between metals and bacterially-generated sulfide is assured. A
more shallow secondary pond would permit the biological uptake of nutrients
such as those contributed from nitrogen explosives and carbonaceous materials
in the coal. This recommendation should be evaluated by experimentation at
the pilot plant level. Hill (1976) discussed the advantages of a multiple
pond system from an engineering standpoint. The physical aspects of sedi-
mentation pond design should be strongly interfaced with considerations
of biological activity within the pond system.
(3) Settling ponds should be located as far from the main focus of
mining activity as practical, and blasting material storage vats should not
be located where their leachates would drain directly into the settling
ponds. Nitrogen enrichment in the ponds, and high turbidity levels from
fugitive dust, may be reduced thereby.
(4) In addition to a source of water for possible irrigation of recla-
mation sites, current plans call for the use of settling pond water to fill
and maintain a northern pike spawning marsh. Influent water should not be
used for these purposes because of the sulfide present. Immature stages
of northern pike are particularly sensitive to hydrogen sulfide. Laboratory
bioassays have indicated that 100 percent mortality occurred at 0.063 and
0.020 mg/liter of hydrogen sulfide for northern pike eggs and sac fry,
respectively (Adelman and Smith 1970). The average levels of hydrogen
sulfide detected in the influent exceeded these lethal limits by one order
of magnitude. However, this same water, after being oxygenated in the
settling pond, contained sulfide concentrations which were more tolerable
for fish culture.
(5) Efforts should be made to maintain normal operation of^the pond
during those times when water must be supplied to the pike spawning marsh.
Dredging of the pond followed by stagnation in winter 1976 resulted in
increased amounts of certain chemical parameters and a markedly lower
concentration of dissolved oxygen in the water column. Effluent from the
settling pond at that time might have produced deleterious effects on a
spawning marsh,
(6) The analytical methods used for the detection of mercury did not
distinguish between the more toxic and less toxic forms; therefore, it is
difficult to assess the potential effect mercury in the pond water may have
on fishes. Mercury concentrations in the pond should be monitored because
its forms are readily accumulated and retained in biological systems.
49
-------
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56
-------
Table A-l. Hater chemistry data for West Pecker Mine settling pond, 27 Only 1976.
(Chemical parameters are expressed in mg/liter unless otherwise specified.)
Site No.
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
c
J
^J
1
2 Surface
3 Surface
3 Bottom
4
•5
6
Temperature
°C
16.2
not sampled
22.5
24.2
22.2
not sampled
--
Chloride
0.6
0.5
0.3
0.3
0.8
Total
Iron
0.145
0.163
0.190
0.198
0.186
Specific
Conductance
umho/cm, 25 C
1495
1746
1750
1739
1717
Fluoride
1.2
1.1
1.1
1.0
1.1
Total
Dissolved
Solids
1002
1170
1172
1165
1150
PH
7.42
8.14
8.17
8.18
8.14
Sulfate
175
420
480
410
180
Total
Non-Filterable
Solids
4.2
13.1
14.9
15.7
27.1
Turbidity
NTU
Total
Alkalinity
as CaC03
389
457
463
454
455
Organic
Carbon
4.2
4.2
4.6
18.2
. 4.6
Calcium
73
78
75
83
80
Total
Hardness
as CaC03
374
393
396
449
449
Nitrate-
Nitrogen
0.023
0.032
0.030
0.339
0.402
Magnesium
47
48
51
59
61
Silica as
Si02
18.0
13.8
16.0
14.1
15,7
Nitrite-
Nitrogen
0.004
0.002
0.004
0.003
0.001
Sodium
185
275
285
245
270
Dissolved
Oxygen
7.80
7.73
8.93
8.31
—
Ammonia-
Nitrogen
0.190
0.108
0.110
0.104
0.115
Potassium
6.5
8.1
7.6
8.7
8.1
Dissolved
Iron
Total
Nitrogen
0.693
0.772
0.830
0.779
0.832
•^
—1
m
70
O
3C 3Z
m m
C_! CO
CO -H
i— m TO
-< o -<
. . fS ^
tfi TO ^^
^*J F^
en 3
1 "Z. |—
m o
"^> 3>
-o co i—
TO m
i— i — 1 ~a
M t-t O
-J £75 O
-J —1
-O I— 1
0<
~Z. 1 — 1
C3 — 1
3^
-o
"D
m
"^
CD
1 — 1
X
1
2 Surface
3 Surface
3 Bottom
4
5
6
Inorganic
Nitrogen
0.217
0.142
0.144
0.446
0.518
Organic
Nitrogen
0.476
0.630
0.686
0.333
0.314
Orthophosphate Tota1
Phosphorus Phosphorus
0
0
0
0
0
.025
.011
.009
.006
.009
0.036
0.036
O.OE7
0.042
0.038
Organic
Phosphorus
0.011
0.025
0.048
0.036
0.029
H9t
0.85
0.90
0.73
0.79
0.87
As
1.6
1.5
1.2
<0.3
1.3
Se
yg/fi
0.4
0.4
0.4
0.6
0.4
Pb
<0.01
<0.01
<0.01
<0.01
<0.01
Cd
<0.001
<-o.ooi
10.001
-------
Table A-2, Water chemistry data for West Decker Mine settling pond, 24 August 1976.
(Chemical parameters are expressed 1n mg/IUer unless otherwise specified.)
in
00
Site No.
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
5
6
Temperature
«c
17.1
not sampled
20.9
20.4
20.0
21.0
20.5
Chloride
<1
-------
Table A-3. Water chemistry data for West Decker Mine settling pond, 19 September 1976.
(Chemical parameters are expressed in rag/liter unless otherwise specified.)
Cn
ID
Site No.
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
Temperature
°C
14.1
not sampled
17.1
16.2
16.1
not sampled
15.9
Chloride
5.5
5.6
5.7
5.6
5.2
Total
Iron
0.100
0.050
0.059
0.056
0.059
Inorganic
Nitrogen
0.766
0.294
0.278
0.239
0.276
Specific
Conductance
Vimho/cm, 25 C
1273
1313
1283
1293
1323
Fluoride
2.0
1.9
2.0
1.8
1.8
Total
Dissolved
Solids
853
880
860
860
886
Organic
Nitrogen
not detectable
•
0.132
0.255
0.136
0.091
PH
7.44
8.37
8.38
8.30
8.34
Sulfate
360
290
315
300
240
Total
Non-Filterable
Solids
1.7
5.4
6.4
13.1
9.2
Orthophosphate
Phosphorus
0.020
0.001
0.003
0.003
0.002
Turbidity
NTU
5
5
5
5
5
Total
Alkalinity
as CaCO-j
445
456
457
456
459
Organic
Carbon
Total
Phosphorus
0.025
0.021
0.024
0.023
0.024
Calcium
68.9
68.0
68.0
66.4
65.2
Total
Hardness
as CaCOj
268
258
246
246
252
Nitrate-
Nitrogen
0.194
0.118
0.126
0.057
0.116
Organic Hg
Phosphorus vig/fc
0.005 0.11
0.020 0.13
0.021 0.53
0.020 0.48
0.022 0.42
Magnesium
23.4
21.5
18.5
19.5
21.7
Silica as
S102
18.0
11.8
12.0
12.4
12.4
Nitrite-
Nitrogen
0.027
0.010
0.012
0.013
0.012
As
wg/«.
3.3
1.5
1.6
1.2
1.2
Sodium
200
210
220
210
210
Dissolved
Oxygen
6.7
10.7
10.8
11.0
10.2
Ammonia-
Nitrogen
0.545
0.166
0.140
0.169
0.148
Se Pb
vg/l
<0.3 <0.1
<0.3 <0.1
<0.3 <0.1
<0.3 <0.1
<0.3 <0.1
Potassium
5.2
5.2
5.2
5.4
5.4
Dissolved
Iron
Total
Nitrogen
0.587
0.426
0.533
0.375
0.367
Cd
<0.005
<0.005
<0.005
<0.005
<0.005
-------
Table A-4. Water chemistry data for Uest Decker Mine settling pond, 21 October 1976.
(Chemical parameters are expressed 1n mg/liter unless otherwise specified.)
Site No.
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
Temperature
»c
13.0
not sampled
6.1
6.4
6.6
6.4
6.1
Chloride
4.9
5.5
6.2
5.8
5.5
5.8
Total
Iron
0.334
0.125
0.125
0.121
0.120
0.126
Inorganic
Nitrogen
0.599
0.630
0.615
0.746
0.638
0.908
Specific
Conductance
ymho/cm, 25 C
1220
1395
1386
1403
1405
1407
Fluoride
1.5
1.9
2.0
2.0
1.9
1.9
Total
Dissolved
Solids
814
930
925
936
937
938
Organic
Nitrogen
0.191
0.300
0.526
0.455
0.126
0.851
PH
7.41
8.47
8.46
8.47
8.46
8.43
Sulfate
228
255
235
280
265
280
Total
Non-Filterable
Solids
4.63
22.43
86.93
18.85
23.64
17.20
Orthophosphate
Phosphorus
0.001
0.007
0.007
0.005
0.005
0.007
Turbidity
NTU
1.4
4.0
4.3
4.4
5.0
4.4
Total
Alkalinity
as CaCOj
418
493
496
493
498
498
Organic
Carbon
Total
Phosphorus
0.047
0.043
0.046
0.061
0.045
0.043
Calcium
73.4
44.1
44.1
38.9
36.1
36.1
Total
Hardness
as CaCO-j
294
260
264
260
264
256
Nitrate-
Nitrogen
6.354
0.430
0.425
0.551
0.443
0.688
Organic
Phosphorus
0.046
<
0.036
0.039
0.056
0.040
0.036
Magnesium
26.8
36.6
37.6
39.7
42.4
40.5
Silica as
S102
17.4
9.8
10.8
8.4
10.6
10.6
Nitrite-
Nitrogen
0.001
0.020
0.020
0.019
0.022
0.022
Hg As
u9/Jt ygA
<0.05 1.5
0.20 1.9
..
0.22 1.5
0.09 1.8
0.11 1.9
Sodium
190
250
250
250
240
250
Dissolved
Oxygen
0.7
11.2
11.1
11.3
11.1
11.0
Anrnonia-
Nitrogen
0.244
0.180
0.170
0.176
0.173
0.198
Se Pb
vg/i
<0.3 <0.1
0.4 <0.1
<0.1
0.3 <0.1
<0.3 <0.1
0.5 <0.1
Potassium
4.5
6.0
5.8
5.8
5.6
5.6
Dissolved
Iron
Total
Nitrogen
0.790
0.930
1.141
1.201
0.764
1.759
Cd
<0.005
<0.005
<0.005
^•flQEI
<0.00b
<0.005
-------
Table A-5. Water chemistry data for West Decker Mine settling pond, 18 November 1976.
(Chemical parameters are expressed in mg/liter unless otherwise specified.)
cn
Site No.
1
2 Surface
3 Surface
3 Bottom
5
6
1
2 Surface
3 Surface
3 Bottom
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
1
2 Surface
3 Surface
3 Bottom
4
5
6
Temperature
«c
not sampled
Chloride
5.7
0.3
0.4
7.2
1.1
Total
Iron
0.086
0.116
0.131
0.086
0.114
Inorganic
Nitrogen
17.1
28.7
32.0
15.5
29.0
Specific
Conductance
umho/cm, 25 C
Iblb
1703
2083
1218
1689
Fluoride
2.0
2.4
2.9
2.0
2.4
Total
Dissolved
Solids
1015
1141
1396
816
1132
Organic
Nitrogen
2.2
1.7
3.3
1.9
2.2
PH
8.48
8.43
8.39
8.47
8.41
Sulfate
215
230
260
180
225
Total
Non-Filterable
Solids
10.92
18.89
47.40
10.49
19.92 ,
Orthophosphate
Phosphorus
0.006
0.005
0.006
0.005
0.006
Turbidity
NTU
13.2
22.5
102
12.6
19.5
Total
Alkalinity
as CaC03
567
633
846
623
689
Organic
Carbon
Jotal
Phosphorus
0.038
0.058
0.075
0.039
0.067
Calcium
30.1
29.7
24.1
25.7
28.1
Total
Hardness
as CaCO-j
186
197
154
161
191
Nitrate-
Nitrogen
15.9
27.3
30.6
14.5
27.6
Organic Hg
Phosphorus \j.g/i
0.032 0.08
0.053 0.09
0.069 0.09
0.034 0.09
0.061 <0.05
Magnesium
38.0
40.8
31.7
33.0
39.5
Silica as
Si02
7.0
8.2
8.4
6.0
8.4
Nitrite-
Nitrogen
0.248
0.240
0.243
0.200
0.260
As
yg/X,
1.9
1.7
2.2
1.5
1.6
Sodium
300
330
430
240
340
Dissolved
Oxygen
10.50
10.70
10.48
9.39
10.16
Ammonia-
Nitrogen
0.92
1.13
1.11
0.83
1.15
Se Pb
1.2 <0.1
1.3 <0.1
2.1 <0.1
1.2 <0.1
1.4 <0.1
Potassium
6.0
6.5
6.8
6.5
6.5
Dissolved
Iron
Total
Nitrogen
19.3
30.4
35.3
17.4
31.2
Cd
<0.005
<0.005
<0.005
<0.005
<0.005
-------
ro
3 Surface
3 Mid-depth
Table A-6. Water chemistry data for West Decker Mine settling pond, 14 December 1976.
(Chemical parameters are expressed 1n mg/liter unless otherwise specified.)
Site No.
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
Temperature
°C
not sampled
1.0
1.0
not sampled
2.5
not sampled
Chloride
0.1
0.1
0.1
Total
Iron
0.069
0.092
0.083
Inorganic
Nitrogen
14.55
11.35
Specific
Conductance
ymho/cm. 25 C
2438
2617
2600
Fluoride
3.1
3.6
3.9
Total
Dissolved
Sol Ids
1633
1753
1742
Organic
Nitrogen
PH
7.83
7.83
7.87
Sulfate
310
335
305
Total
Non-Filterable
Solids
10.36
16.59
8,54
Orthophosphate
Phosphorus
not detectable 0.004
2.08
0.004
Turbidity
NTU
5.3
5.1
4.5
Total
Alkalinity
as CaC03
916
914
940
Organic
Carbon
Total
Phosphorus
0.026
0.043
Calcium
42.1
42.5
40.9
Total
Hardness
as CaC03
234
239
246
Nitrate-
Nitrogen
9.30
8.54
8.98
Organic
Phosphorus
0.022
0.039
Magnesium
46.8
48.0
50.0
Silica as
S102
8.2
9.6
10.4
Nitrite-
Nitrogen
0.204
0.260
0.325
Hg As
vg/t yg/J.
0.36 1.4
0.30 1.2
Sodium
420
440
430
Dissolved
Oxygen
2.28
2.33
2.07
Ammonia-
Nitrogen
2.24
2.55
2.31
Se Pb
yg/i
2.3 <0.1
2.2 <0.1
Potassium
8.5
8.6
8.9
Dissolved
Iron
Total
Nitrogen
13.74
13.43
13.79
Cd
<0.005
<0.005
11.61
2.18
0.003
0.032
0.029
0.18
1.1
2.5
<0.005
-------
Table A-7. Water chemistry data for West Decker Mine settling pond, 12 January 1977.
(Chemical parameters are expressed in mg/liter unless otherwise specified.)
cn
oo
Site No.
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
Temperature
°C
not sampled
0.5
0.5
not sampled
0.0
not sampled
Chloride
Total
Iron
0.056
0.105
0.128
Inorganic
Nitrogen
14.30
13.70
14.94
Specific
Conductance
umho/cm, 25
2889
2958
3222
Fluoride
Total
Dissolved
Sol ids
1936
1982
2159
Organic
Nitrogen
0.16
0.40
0.36
C pH
8.05
8.00
7.97
Sulfate
494
494
588
Total
Non- Filterable
Solids
5.56
18.35
—
Orthophosphate
Phosphorus
0.009
0.009
0.006
Turbidity
NTU
Total
Alkalinity
as CaCOg
1153
1188
1277
Organic
Carbon
Total
Phosphorus
0.033
0.054
0.063
Calcium
72
74
78
Total
Hardness
as CaC03
316
317
348
Nitrate-
Nitrogen
10.36
9.78
10.82
Organic
Phosphorus
0.024
0.045
0.057
Magnesium
59.5
59.3
65.9
Silica as
Si02
Nitrite-
Nitrogen
0.245
0.220
0.178
Hg As
pg/i pg/2
0.20 1.1
0.18 0.9
0.39 1.4
Sodium
490
530
550
Dissolved
Oxygen
2.45
2.42
2.04
Ammonia-
Nitrogen
3.70
3.70
3.94
Se Pb
vg/i
2.3 <0.2
2.0 <0.2
2.3 <0.2
Potassium
Dissolved
Iron
0,019
0.015
0.015
Total
Nitrogen
14.46
14.10
15.30
Cd
<0.005
<0.005
<0.005
-------
Table A-8. Water chemistry data .for West Decker Mine settling pond, 9 February 1977,
(Chemical parameters are expressed In mg/liter unless otherwise specified.)
Site No.
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
1
2 Surface
2 Bottom
3 Surface
3 Mid-depth
6
Temperature
°C
not sampled
1.5
3.0
not sampled
0.5
not sampled
Chloride
Total
Iron
0.104
0.079
0.051
Inorganic
Nitrogen
11.06
5.80
5.81
Specific
Conductance
umho/cra, 25
2320
3000
3120
Fluoride
Total
Dissolved
Sol Ids
1554
2010
2090
Organic
Nitrogen
2.57
2.07
3.48
C pH
7.94
7.95
7.92
Sul fate
455
581
612
Total
Non-Filterable
Solids
5.39
8.36
8.24
Orthophosphate
Phosphorus
0.003
0.005
0.004
Turbidity
NTU Calcium Magnesium
Total Total
Alkalinity Hardness Silica as
as CaCOo as CaC03 S102
885
1005
t
1086
Organic Nitrate- Nitrite-
Carbon Nitrogen Nitrogen
6.19 0.210
3.78 0.018
3.09 0.015
Total Organic Hg As
Phosphorus Phosphorus vq/i ug/K.
0.029 0.026 0.31 1.1
0.037 0.032 0.28 1.3
0.027 0.023 0.14 1.3
Sodium
700
830
830
Dissolved
Oxygen
1.19
1.49
1.23
Ammonia-
Nitrogen
4.66
2.00
2.70
Se Pb
ug/a
3.1 <0.1
2.6 <0.1
2.2 <0.1
Potassium
9.7
11.4
11.4
Dissolved
Iron
Total
Nitrogen
13.63
7.87
9.28
Cd
<0.005
<0.005
<0.005
-------
Table A-9. Water chemistry data for West Decker Mine settling
pond, 6 April 1977
Hg As Se Pb Cd
Site No. (|jg/liter) (ug/liter) ((jg/liter) (mg/liter) (mg/liter)
1 0.58 1.6 <0.3 <0.1 <0.005
2 Surface 0.28 1.2 0.3 <0.1 <0.005
3 Surface 0.25 1.2 0.3 <0.1 <0.005
6 0.38 1.1 0.5 <0.1 <0.005
65
-------
Table A-10. Productivity estimates at Site 3,
West Decker Mine settling pond
A. Diurnal oxygen curves for community productivity
Date of
measurement
27-28 July 1976
23-24 August 1976
19-20 September 1976
20-21 October 1976
17-18 November 1976
14-15 December 1976
Gross primary
productivity
(g 02/m2/day)
8.44
7.63
4.57
0.23
0.43
0.16
Respiration
(g 02/m2/day)
8.64
5.52
1.32
0.58
1.22
0.47
Net primary
productivity
(g 02/m2/day)
0
2.11
3.25
0
0
0
B. Radioactive carbon uptake for planktonic productivity
Date of
measurement
28 July 1976
25 August 1976
*
21 September 1976
22 October 1976
18 November 1976
15 December 1976
Productivity
(g C/m2/day)
8.83 x 10
4.42 x 10
1.16 x 10
1.29 x 10
-2
-2
-1
2.49 x 10
0
-2
-2
66
-------
Table A-11. Pigment concentrations of samples taken at Site 3,
West Decker Mine settling pond
Pigment concentrations (mg/m3)
Date of sample
Collection
29 June 1976
28 July 1976
24 August 1976
19 September 1976
21 October 1976
18 November 1976
14 December 1976
12 January 1977
9 February 1977
Chlorophyll a
monochromatic trichromatic
0
1.255
1.202
4.606
3.155
4.806
6.675
521.2
35.82
1.059
3.269
1.309
4.979
3.699
6.961
356.9
42.00
Chlorophyll
b
0.076
0
0
0.293
0.077
0
0
0
Chlorophyll
c
0.144
0.553
0
2.034
1.402
1.515
60.3
1.59
Phaeopigments
3.044
3.277
0.107
3.571
2.961
0
0.174
0
8.81
-------
Location of
artificial
substrates
Table A- 12. Pigment and bioaccumulation data for periphytic populations,
West Decker Mine settling pond
Pigment concentrations (mg/m3)
Chlorophyll a
Period of Mono- Tri- Chlorophyll Chlorophyll Phaeo- Bioaccumulation
incubation chromatic chromatic b c pigments (mg C/m2/day)-'
00
Mine effluent 12 May- 54.49
below flume 27 June 1976
(46 days)
27 June- 13.54
28 July 1976
(31 days)
28 July- 0.351
25 August 1976
(28 days)
25.89
10.33
6.63
0.027
16.84
0.91
0.332
46.99
4.81
1.956
100.2
300.5
17.2
Within pond
near stand-
pipe
21 September-
22 Oct 1976
(31 days)
23 October-
18 Nov 1976
(26 days)
24.66
23.78
data inconsistent
8.42
0.45
439.0
-' mg C calculated as 50% of the ash free dry weight of, organic matter (Stockner and Shortreed 1976),
-------
Table A-13.
Summary of results of laboratory algal bioassays,
West Decker Mine settling pond
Test water
Sampling date
Limiting nutrient(s)
Effluent
(Site 6)
Influent,/
(Site 1)§/
South Pond
(Site 3)
3 November 1975
15 January 1976
19 March 1976
21 April 1976
25 May 1976
1 July 1976
29 July 1976
26 August 1976
22 September 1976
23 October 1976
19 November 1976
15 January 1976
21 April 1976
25 May 1976
1 July 1976
22 September 1976
16 December 1976
nitrogen and phosphorus;
primarily nitrogen
phosphorus
nitrogen and phosphorus;
primarily phosphorus
phosphorus
nitrogen, phosphorus and trace
elements; primarily phosphorus
nitrogen and phosphorus;
primarily nitrogen
nitrogen and phosphorus
nitrogen and phosphorus
nitrogen and phosphorus;
primarily phosphorus
phosphorus
phosphorus
nitrogen and phosphorus
phosphorus
nitrogen and phosphorusy
nitrogen
b/
nitrogen and phosphorus
phosphorus-
-' Prior to June 1976 all influent samples collected from sump pond.
- Poor replication.
c/
Productivity very low.
69
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-79-125
3. RECIPIENT'S ACCESSION NO.
«. TITLE AND SUBTITLE
Environmental Effects of Western Coal Surface Mining.
Part IV - Chemical and Microbiological Investigations of
a Surface Coal Mine Settling Pond
5. REPORT DATE
December 1979 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
S. C. Turbak, G. J. Olson, and G. A. McFeters
8. PERFORMING ORGANIZATION REPORT NO.
. PERFORMING ORGANIZATION NAME AND ADDRESS
Natural Resource Ecology Laboratory '
Colorado State University
Fort Collins, CO 80523
1O. PROGRAM ELEMENT NO.
1NE625
11. CONTRACT/GRANT NO.
R803950
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Research Laboratory - Duluth,
3ffice of Research and Development
J. S. Environmental Protection Agency
Duluth, Minnesota 55804
Minnesota
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/03
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Chemical and microbiological investigations of the settling pond system at the
West Decker Coal Mine in southeastern Montana were undertaken during 1975-1977. Con-
centrations of total dissolved solids, bicarbonate, sodium, sulfate, and nitrogen
species in pond water were elevated in comparison to those in other nearby surface
waters; however, it was concluded that these would not significantly impact the nearby
Tongue River or Tongue River Reservoir. Constituents of the mine drainage waters
underwent chemical changes within the pond which were at least in part due to the
activities of microorganisms. The increase in pH value and in concentration of dis-
solved oxygen, partially attributed to photosynthesis within the pond, oxidized re-
duced chemical species such as sulfide and ferrous iron. The high numbers and activity
ueasurements of sulfate reducing bacteria as well as the significant amount of metal-
)ound sulfides in pond sediments made a strong case for the contributions of these
arganisms to metal precipitation in, and possible detoxification of, pond waters.
Hcidophilic iron and sulfur bacteria, responsible for the production of acid mine
drainage, were consistently detected within the pond system and other locations at
Jecker. However, no acidic conditions were observed, most likely because relatively
n'gh concentrations of mineral carbonate in the overburden neutralized acid formed
From pyritic materials present.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Settling ponds
Microbial changes
Acid bacteria
Coal mine runoff
Mine drainage
Western energy dev.
Coal mining
Water quality
68/D
06/F
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
80
2O. SECURITY CLASS (This page)
UNCLASSIFTFR
22. PRICE
EPA fatm 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
70
•US GOVtmKENI HHHIIH6 OfflCt 1MO -657-146/55Z7
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