MEASURES FOR THE RESTORATION AND
ENHANCEMENT OF QUALITY
OF FRESHWATER LAKES
UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
1973
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MEASURES FOR THE RESTORATION AND
ENHANCEMENT OF QUALITY OF FRESHWATER LAKFS
by the
Office of Air and Water Programs
Division of Water Quality and Non-Point Source Control
and the
Office of Research and Development
National Eutrophication Research Program
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Washington, D.C. 20460
EPA-430/9-73-005
For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington, D.C. 20402 - Price $2.86
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FOREWORD
The limited number of publicly owned high
quality freshwater lakes in the United States
combined with a growing population has resulted in
a pressing need for sound management programs
designed to protect and enhance the quality of the
Nation's lakes.
The Federal Water Pollution Control Act
Amendments of 1972 require the Administrator of
the Environmental Protection Agency to issue
information on methods, procedures and processes
as may be appropriate to restore and enhance the
quality of the Nation's publicly owned freshwater
lakes [Subsection 304(i), PL 92-500], This report
is prepared pursuant to that legislative mandate.
Robert W. Fri
Acting Administrator
Environmental Protection Agency
iii
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LIST OF PARTICIPANTS
WORKING GROUP MEMBER CONTRIBUTORS
Office of Air and Water Programs
Division of Water Quality and Non-Point Source Control
Mr. W. L. Kinney, Subcommittee Chairman
llr. J. I. Lewis, Alternate Subcommittee Chairman
Dr. L. J. Guarraia
Mr. J. P. Gating
Mr. D. K. Boynton, Jr.
Office of Research and Development
Division of Processes and Effects
Dr. F. G. Wilkes
Office of Radiation Programs
Criteria and Standards Division
Mr. R. S. Dyer
NON-WORKING GROUP MEMBER CONTRIBUTORS
National Eutrophication Research Program
Mr. T. E. Maloney Dr. S. A. Peterson
Dr. K. W. Malueg Dr. W. D. Sanville
Mr. D. W. Shults Dr. F. S. Stay, Jr.
Dr. C. F. Powers
iv
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WORKING GROUP MEMBER REVIEWERS
Office of Air and Water Programs
Mr. K. M. Mackenthun
Mr. B. W. Everling
Office of Research and Development
Dr. D. Yount
Mr. D. Ehreth
Office of Hazardous Materials Control Programs
Mr. V. Grey
Mr. E. Brooks
Office of Enforcement and General Counsel
Mr. A. W. Eckert
Office of Federal Activities
Mr. P. Smith
Office of Planning and Management
Mr. J. Jacknow
Office of International Affairs
Mr. J. Tarran
NON-WORKING GROUP MEMBER REVIEWERS
Dr. D. Duttweiler
Southeast Environmental Research Laboratory
Athens, Georgia
Dr. L. P. Seyb
Pacific Northwest Environmental Research Laboratory
Co rvallis, Oregon
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NON-WORKING GROUP MEMBER REVIEWERS (Cont.)
Mr. F. H. Rainwater
National Thermal Research Program
Corvallis, Oregon
Mr. R. M. Brice
Shagawa Lake Research Project
Ely, Minnesota
Mr. H. J. Fisher (ret.)
Region V
Chicago, Illinois
ACKNOWLEDGEMENT
The technical and editorial assistance of Mrs. Marian
Musser is gratefully acknowledged.
vi
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CONTENTS
Section Paae
Foreword
List of Participants
Acknowledgement
I SUMMARY
II INTRODUCTION
LEGISLATIVE AUTHORITY
SCOPE OF TIIE PROBLEM
III LAKE ENVIRONMENTS 14
LAKE TYPES 15
THERMAL REGIMENS OF LAKES AND RESERVOIRS 19
NUTRIENT CYCLING 23
IV POSSIBLE REMEDIAL MEASURES FOR RESTORING AND
ENHANCING THE QUALITY OF THE NATION'S PUBLICLY
OWNED LAKES 34
RESTRICTING THE NUTRIENT AND SEDIMENT INPUT 38
Point Source Nutrient Removal and Control 38
Nutrient Diversion 46
Control of Allocthonous Sediments 58
IN-LAKE TREATMENT AND CONTROL MEASURES 61
Dredging 61
Nutrient Inactivation 71
Dilution and Displacement 81
Covering of Sediments' 84
Artificial Destratification and Hypolimnetic
Aeration 86
Drawdown108
Harvesting Nuisance Organisms 112
Biological Control of Nuisance Organisms 124
Chemical Control of Nuisance Organisms130
CONTROL AND REMOVAL OF HAZARDOUS SUBSTANCES 134
POSSIBLE LAKE PROTECTION MANAGEMENT
CONSIDERATIONS - 150
V REFERENCES 152
VI l
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VI APPENDIX 171
LAKE PROBLEMS 171
SOURCES OF WATER QUALITY PROBLEMS IN LAKES 171
Industrial Wastes 172
Municipal Wastes 177
Agricultural Wastes 178
Miscellaneous Sources 179
Mine Drainage 179
Oil and Hazardous Materials 180
Watercraft Wastes181
IMPACT OF CONTAMINANTS ON LAKE ENVIRONMENTS 181
Eutrophication 182
Natural and Accelerated
(Cultural) Eutrophication 184
Consequences of Eurrophication 184
Sedimentation188
Effects of Sediments 188
Sources of Sediments 194
Thermal Pollution197
Effects of Thermal Pollution 198
Sources of Thermal Pollution 203
Selected Toxic Substances203
Pesticides 204
Mercury" 211
Polychlorinated Biphenyls (PCB's) 219
>iy
n-h"
Phthalate Esters 221
Arsenic222
Ammonia' and Sulfides 225
Miscellaneous Problems 227
Non-toxic Salts 227
Radioactive Wastes 230
REFERENCES232
viii
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List of Tables
Table Page
1 Comparison of Nitrogen Removal
Processes 41
2 Treatment Plant, Operating and
Maintenance Costs for Phosphorus
Removal 42
3 Physical Characteristics of the
Madison Lakes 53
4 Summary of Manpower, Basic Equipment
and Costs for Alum Treatment of
Horseshoe Lake, Wisconsin 77
5 Initial Costs Per Unit Volume
(Purchase and Installation) 95
6 Operating Costs Per Unit Volume
and Time (Energy and Maintenance) 95
7 Morphological Characteristics of
Bullock Pen, Boltz and Falmouth Lakes 104
8 Estimated Fixed/Variable Costs of
Distributing Sand in an Area South of
Wyandotte 142
9 Estimate of the Cost Involved in the
Application of 7.6 cm of Sand to
0.8, 10.1 and 20.2 Hectares of
Sediment Contaminated with Mercury 143
APPENDIX
I Estimated Volume of Industrial
Wastes before Treatment, 1964 174
II U.S. Electric Power - Past Use,
Future Estimates 175
III Use of Cooling Water by U.S.
Industry 176
IV Number of Reported Oil Spills
in U.S. Waters (over 100 barrels) 180
V Annual Loss of Retaining Volume
for 148 Lakes 189
ix
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VI Effect of Inert Suspended Solids
on Freshwater Fish 190
VII Effect of Turbidity on Fish
Reproduction 191
VIII Summary of Total Mercury Measured
in Water Samples from Rivers and
Lakes Obtained During Oct. and
Nov., 1970 216
IX State Fishing Restrictions Because
of Mercury—Sept. 1, 1970 217
X Mercury Residues in Fish - 1969
and 1970 218
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List of Figures
Figure Page
1 Eutrophication: The Process of
Lake Aging by Natural Succession 18
2 Diagrarmatic Sketch Showing Thermal
Characteristics of Temperate Lakes 22
3 Phosphorus Cycle 25
4 Sulfur Cycle 27
5 Nitrogen Cycle 29
6 Carbon Cycle 33
xi
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Section I
SUI1MAPY
The increasing rate of deterioration of the Nation's
public waters has resulted in passage of the Federal Water
Pollution Control Act Amendments of 1972, PL 92-500.
Included within this legislation is the requirement that the
Administrator of the United States Environmental Protection
Agency issue such information on methods, processes and
procedures as may be appropriate to restore and enhance the
quality of the Nation's publicly owned lakes [subsection
304(i) ]. This report is prepared pursuant to that
legislative mandate. It contains state-of-the-art
information only and the methods have not been subjected to
cos t an a lys es.
Lakes vary tremendously in their chemical, physical and
biological characteristics depending upon their mode of
origin, their location, the characteristics of their
watersheds and their uses. Consequently, lake problems also
vary, and most must be dealt with on a case-by-case basis.
Contaminants may impact upon lake environments in
various ways depending upon the nature of the substance.
Nutrient rich plant growth stimulators such as domestic
sewage and commercial fertilizers cause accelerated
eutrophication: sedimentation may add to the eutrophication
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problems or create unique problems in the absence or
eutrophication: toxic substances nay poison water supplies,
interfere with normal biological activity or render
commercial and sports fish and crustaceous species unfit for
consumption. Heated water released to lakes may alter tne
natural thermal structure and upset the composition or" laKe
communities.
Lake restoration measures are not well developed, with
much of the technology still in experimental stages in
laboratories or in small pilot lakes. Certain tecnniques
have met with varying degrees of success on indiviaual
lakes, but their applicability to ether lakes is unknown.
At this point in time it is impossible to recommend remedial
measures which will prove effective for all lakes or even
particular classes of lakes. It is the responsibility of
lake managers to define the problems and to implement
rehabilitation or enhancement programs which are best fitted
to the requirements of particular lakes on a case-by-case
basis.
The approach to the rehabilitation of degraded lakes is
twofold: (1) restricting the input of undesirable materials
and (2) providing in-lake treatment for the removal or
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inactivation of undesirable materials. Reducino or
eliminating the sources of waste loading is the only
restorative measure needed to achieve the desired level of
improvement in certain lakes in which natural flushing
results in substantial improvements in quality. However, in
many lakes, particularly those with slow flushing rates, in-
lake treatment schemes may also be required before
significant improvements will be realized.
Remedial measures which restrict the input of
contaminants include advanced wastewater treatment, nutrient
diversion and allochthonous sediment control.
Advanced wastewater treatment (AWT) probably represents
the best method currently available for curbing nitrogen and
phosphorus input to waterways at moderate costs. Phosphorus
removal efficiency of 80-95 percent can be achieved by
chemical precipitation with alum, lime or ferric salts.
Removal of ammonia and other nitrogen species can be
accomplished by ion exchange, ammonia stripping, breakpoint
chlorination or bacterial denitrification. Although to date
there has not been documentation evaluating AWT as a means
of restoring a lake, preliminary results both in this
country and in Europe have been encouraging.
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Nutrient diversion offers a possible restoration
technique in situations where the incoming nutrient loaa is
entering from point sources. This technique has been used
successfully in Lake Washington and has resulted in some
improvement in the Madison Lakes. Preliminary stuaies on
several lakes indicate that the effects of diversion may not
be readily apparent in small, shallow, highly eutropaic
lakes, due to the remobilization of nutrients from the
sediment pool and the continued influx of nutrients from
non-point sources.
The useful existence of a lake or reservoir can
sometimes be prolonged by implementing control measures to
reduce the rate of sedimentation. Prudential land use
management practices within the watershed which minimize
erosion associated with construction, farming, road building
and forestry activities tend to reduce the volume of
sediment input to lakes. Filter dams and desilting basins
are effective sediment traps under certain conditions.
Sediment control measures not only reduce the rate at whxcn
a lake basin is filled, but also restrict the input of
nutrients adsorbed to sediment particles.
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In-lake treatment, measures which have been usea in lake
restoration programs or which are now being investigated
include dredging, nutrient inactivation, dilution ana
displacement, covering of sediments, artificial
destratification and hypolimnetic aeration and drawuown.
Lake dredging not only removes sediment buildup, but
also serves to remove a potential nutrient source. Little
information is available on the chemical and bioloyioal
effects of dredging, but projects are now under way waicn
will evaluate the total environmental effects. Tne
relatively high costs of dredging make this technique
prohibitively expensive on most large lakes, but aredging as
a restorative method has been used successfully for years on
small lakes and ponds.
Nutrient inactivation in lakes is accomplished by adding
some type of material to the water that will bond witn,
adsorb or otherwise render nutrients unavailable to aquatic
plants. Alum, sodium aluminate, fly ash arid various other
materials have been investigated as nutrient inactivation
agents. Although some pilot lake results with this
/
technique have been encouraging, its applicability on a
large scale has not been determined.
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Under certain conditions the water quality of lakes can
be improved by diluting or replacing the existing lake water
with water of a higher quality. This technique has been
used successfully in Green Lake, Washington and a few
others. Its applicability is limited to lakes with reauy
access to a large supply of high quality water.
Covering of bottom sediments with sheeting materials or
particulate matter is being investigated as a means or
preventing nutrient exchange and retarding rooted plant
growth. Limited experiences with this technique have
encountered problems with ballooning of sheeting and
rupturing seals of particulate matter when gas is produced
within the sediments. Investigations of this tecnnique in
pilot lakes are continuing.
It is sometimes possible to replenish the oxygen supply
of anaerobic bottom waters of eutrophic lakes by disrupting
the thermal stratification or by aerating the hypolimnion
directly without disturbing the thermal regimen. Definite
improvements in water quality and in the biota have occurred
as a result of artificial destratification and hypolimnetic
aeration. Although the response ot a given lake to these
treatment measures is unpredictable, destratitication and
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hypolimnetic aeration are potential mechanisms for improving
the water quality of certain lakes.
Lake drawdown has been investigated as a control measure
for rooted aquatic vegetation, as a means of retarding
nutrient release from the sediments and as a lake deepening
mechanism through sediment consolidation. Drawdown tias
shown promise as a successful remedial method in Florida,
but results in Wisconsin are inconclusive. Lake drawdown
studies are continuing.
In many lakes in advanced stages of eutrophication
attempts have been made to control nuisance organisms
through mechanical, biological and chemical means.
Mechanical harvesting can be an effective technique for
removing excess aquatic plants, but it generally is not
economically feasible on a self supporting basis due to the
limited market for the product. Biological control agents
for algae and macrophytes range from the viruses to the
manatee. Although certain organisms have proved to be
useful control agents, much work with biological control,
particularly with the viruses, needs to be undertaken before
it will have universal application. Various chemicals have
long been utilized to control or eliminate unclesired aquatic
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8
flora and fauna. Chemical agents, however, offer only
*
temporary, symptom suppressing relief, and often the
treatment must be repeated to achieve the desired results.
Contamination of lakes with various hazardous substances
is an ever present threat. In order to avoid major
catastrophies resulting from spills, industrial accidents
etc., measures for the control and removal of hazardous
materials must be implemented.
Decontamination of lakes polluted with toxic substances
has been accomplished by filtering the lake water through
activated charcoal filters. Several means of removing
mercury from waters and sediments have been proposed and
used in the laboratory, but few have been demonstrated in
field situations.
Several state and local governments have established
statutes dealing with various aspects of lake management and
rehabilitation as a means of protecting inland lake
environments, but explicit statutes authorizing specific
state or local programs are often badly fragmented among
state agencies and local units of government.
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Section II
INTRODUCTION
LEGISLATIVE AUTHORITY
An ever increasing rate of deterioration in tne
of the Nations's waterways combined with increasea puulic
need for clean water, has resulted in a public awareness of
the Nationfs water quality problems and a demand that action
be taken to alleviate the problems.
The pressing need fcr sound water quality management
programs has resulted in the enactment of the Federal water
Pollution Control Act Amendments of 1972 designed to restore
and maintain the chemical, physical and biological integrity
of the Nation's waters. Included within this Act is trie
requirement that "...The Administrator[of the Environmental
Protection Agency] shall, within 270 days after the
effective date of this subsection (and from time to time
thereafter) issue such information on methods, procedures
and processes as may be appropriate to restore ana enhance
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10
the quality of the Nation•s publicly owned tresh water
lakes" - Subsection 30<*(i), PL 92-500.
This report, prepared pursuant to subsection J04(i),
PL 92-500, provides background information on lake
environments followed by state-of-the-art information on
remedial measures for enhancing and restoring the quality ot
lakes, ponds and reservoirs as required by the legislation.
Discussion of major lake problems is included in an
appendix. Since most lake restoration techniques are
presently in experimental stages, it is impossible to
provide a thorough evaluation and complete cost-
effectiveness analysis at this time. However, as the
experimental programs now underway are evaluated and as new
technology becomes available, subsequent reports documenting
the latest technological and scientific achievements
relating to lake restoration will be forthcoming.
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SCOPE OF THE PROBLEM
The limited number of publicly owned fresh water ldK.es
in the United States combined with increasing population arid
industrial pressures are major factors contributing to tneir
unique and widespread water quality problems. Discharges or
organic and inorganic wastes resulting from urbanization,
cultural and technological advancement, and new water
dependent industries have caused noticeable degradation ot
lake environments in many areas. The problem, in National
perspective, presents a complex interrelationship of urban
development, industrial growth, potable water supply
demands, recreational needs and maintenance of virgin area
resources.
Aesthetic and environmental considerations aside, tne
demand for clean lakes for private, public, and commercial
use is of vital economic concern. Design of a successful
water management program depends upon an understanding ot
the impact of man's activities upon fresh water environments
and the means of ameliorating harmful processes.
Effects of waste discharges on the quality of tne
aquatic environment may be manifested as subtle long term
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12
changes in the fauna and flora or dramatic and seemingly
immediate as in the sudden appearance ot alqal blooms,
aquatic weeds or dead fish. Along with the alterations ot
the species composition of the animal or plant lite, snitts
occur in population densities with the ascendence or large
populations of often undesirable species. Sports tisn are
replaced by "trash" fish, clean water associated bentnic
organisms are replaced by sludge worms and other pollution
tolerant forms, and the normal phytoplankton crops are
replaced by large populations of scum formina blue-green
algae. In addition, human health becomes threatened due to
the establishment of pathogenic ir.icroorganisrcs associated
with fecal and other waste discharge.
Reduction ot water related activities follows alteration
of aquatic life. Boating, swimming, and water skiing
activities must be halted as lakes become choked with
aquatic weeds and as surface algal scums develop. Economic
losses result from a decline of commercially important
aquatic species and with the curtailment of water related
recreational activities.
Industrial and municipal water supplies are also
aftected by water quality degradation. Industrial raw water
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13
often must be treated to the desired quality. If water is
uncontaminated, costs of water processing decrease, possibly
affecting final consumer cost. Toxic materials and
pathogenic microorganisms in municipal raw water supplies
can affect health and increase the costs of processing. Tne
taste, color and odor of water often make people reluctant
to draw water from contaminated sources. In effect, tnis
limits water supply and increases the costs to the consumer.
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1U
Section III
LAKE ENVIRONMENTS
Lakes are temporary features of the landscape, nearly
all of which are very young on the geological, but very old
on the human, time scale. With the passage of time, all
lakes presumably would cease to exist as a consequence of
natural physical and biological processes. Under natural
conditions these processes would require several hundreds or
thousands of years. With the appearance of man on the scene
and as a result of his activities, however, these processes
have been accelerated dramatically, and the maturation or
aging rates of many lakes have been signiiicantly increased.
In the discussion which follows, the limnological
aspects of lake environments including chemical, physical
and biological phenomena are briefly explored. A general
understanding of the lake as an ecosystem is prerequisite to
an appreciation of lake problems.
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LAKE TYPES
Often lakes are formed by some geological event sucn as
subsidence, faulting, damming of river valleys or by tne
eroding and damming action of glaciers. Natural la*ces are
usually formed in infertile basins with low potential tor
biological productivity. Thus they are generally poor with
respect to dissolved nutrients and biological production in
their early history, becoming more fertile with time as
nutrients are carried in from the drainage basin. Man-made
lakes (reservoirs) are frequently created by the inundation
of highly fertile river valleys rich in nutrients necessary
for b'iological production. Such reservoirs which have been
created in fertile areas will usually exhibit an immediate
high degree of biological activity which, if nutrients are
not constantly carried in via tributary streams or other
runoff, will decline after a few years as nutrients are
accumulated in the bottom sediments or otherwise become
biologically unavailable. Many reservoirs, however, are
created by the confinement of rivers with very hign nutrient
concentrations which, through contaminated inflow, maintain
the fertility and productivity of the impoundment.
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In glaciated North America, nutrient-poor melt waters
filled ice-formed basins, creating lakes of various sizes,
shapes, and depths. Many of these lakes, particularly
large, deep ones, have changed relatively little since their
formation and still retain their nutrient-poor
characteristics. Such lakes, low in dissolved nutrient
content and biological production are of the type classified
as. "oligotrophic". Oligotrophic lakes are characterized by
deep basins with large volumes of deep (hypolirnetic)
waters, low organic and nutrient content, high dissolved
oxygen concentration at all depths throughout the year, and
low biological productivity. Phytoplankton crops are
quantitatively restricted, represented by many species of
diatoms and green algae. The deep bottom fauna is
characteristically sparse and is represented by such forms
as fingernail clams, crustaceans, insect larvae and
segmented worms. Cold water fishes such as the salmonids
and whitefish are typical of oligotrophic lakes.
llany other lakes, usually smaller and shallower, are
rich in dissolved nutrients and are hicrhly productive.
These are "eutrophic" lakes. In eutrophic lakes organic
content of the sediments and the water column is high and
nutrients are abundant. Oxygen depletion may occur
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•seasonally in the deeper portions. Diatoms, green, and
blue-green algae are the major phytoplankton types, with
seasonal shifts in dominance usually apparent. During the
suiiror, Mue-green algae J: loops nay occur regularly, often
in nuisance quantities. The bcnthic organisms of the. deeper
waters consist of npecics which are able to survive in tho
low dissolved oxygen concentrations which occur
periodically. Tubificid worris and ridge larvae may be very
abundant. Fish populations usually consist of warm water
species such as perch, pike, bass, panfish, and bullheads.
These lakes eventually succeed into ponds, marshes or
swar.ips, and thence to dry land (Fig. 1).
The distinctions between oligotrophic and eutrophic
lakes is sor.etines not sharply delineated, and the term
"mesotrophic" is often used to describe lakes which have
characteristics of both. Many of the nation's better
recreational lakes are in a state of mesotrophy, having
evolved through their oligotrophic state to the point where
they are roderately productive but have not yet developed
nuisance conditions.
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M esotrophlc Lake
Ollgotrophlc Lake
Eutrophlc Lake
Pond,Marsh or Swamp
Dry Land
00
Figure i .—Eutrophfeation - the process of aging
by ecological succession.
Sourcefl)
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THERMAL REGIMENS OF LAKES AND RESERVOIRS
The thermal regimens of lakes exert a profound effect
upon overall lake ecology, primarily because of tne
associated phenomenon of thermal stratification.
Seasonal changes in air temperature induce changes in
water temperature resulting in a cycle of events of mixing
and stratification which controls the dispersion of
nutrients and dissolved gasses throughout the water column
thereby affecting the biological activity in the lake
(Fig, 2).
During the winter, surface water under ice cover ana
frequently open water are very near 0 C. Since water
reaches its maximum density at 4 C, the warmer, denser
waters will occur at the bottom of the lake. This is
inverse stratification. With the gradual warming ot surface
waters in the spring of the year, the lake becomes
homothermous throughout at a temperature of 4 C. Under
these conditions, winds generate mixing action whicn may be
complete from top to bottom even in very deep lakes,
distributing nutrients, dissolved oxygen and other materials
throughout the water. As spring progresses into summer.
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20
surface waters continue to warm, and a layer of rapidly
decreasing temperature called the "thermocline" or
"metalimnion" is formed, acting as a barrier which prevents
the warm upper "epilimnetic" waters from mixing with the
cool, deeper, heavier "hypolimnetic" waters. The
hypolimnetic waters are effectively isolated from tne
overlying layers and the atmosphere, and if the volume ot
the hypolimnion is small and the oxygen consumption rate is
high, these bottom waters may become depleted of oxygen.
This tends to be the case in many eutrophic lakes. This
condition will persist until the entire lake once again
becomes homothermous in the fall as the surface waters cool.
Mixing from top to bottom then occurs, and the bottom waters
are reoxygenated. As winter progresses, surface water
temperatures again approach 0 C, and the inverse
stratification patterns are again established.
Reservoirs are affected by all of the processes triat
influence natural lakes, and in addition, are strongly
influenced by the hydraulic effects of both the inflow and
discharge. Reservoirs with high discharge to volume ratios
are often completely mixed during the summer due to the
rapid movement of water. Deep reservoirs with a low
discharge to volume ratio often exhibit the classical lake
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21
stratification cycle. Operation of the reservoir aiscnarge
can have a major influence on the thermal structure. i'ne
use of multiple outlet structures at various dep-tna can
provide pre-selected discharge temperatures when
stratification exists, which in turn provides modiLication
of the thermal regimen.
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Figure 2
Diagramatic sketch showing thermal
characteristics of temperate lakes
* J Metal imnion
(thermocline)
Summer
Spring Fall
Winter
Dissolved oxygen (mg/l) Dissolved oxygen (mg/l) Dissolved oxygen (mg/l)
O 2 4 6 8 1O 12 14 O2
0
5
1O
15
2O
I25
E 3C
* 35
£
a 40
•
O 45
50
55
6O
65
6 8 1O 12 14
a
O
d
I I
I
O 4 8 12 16 2O 24 28
Temperature "C
Stratification
4 8 12 16 2O 24 28
Temperature °C
Isothermal
2 4 6 8 1O 12 14
4 8 12 If 2O 24 28
Temperature °C
Inverse stratification
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23
NUTRIENT CYCLING
Development of successful water management programs and
restoration planning depends upon as complete a knowledge as
possible of both the physical and biological processes
working within a particular system. The turnover rates and
exchange of nutrients with the sediments are in p
governed by biological communities.
Before proceeding, the term "nutrients" nust DC
because the definition of "nutrient" depends upon trie
individual involved. "Nutrients" refer to not only organic
material, simple and complex, but to trace elements,
vitamins, and also the major inorganic elements: t>nospnor us,
sulfur, nitrogen and carbon. For the sake of brevity, only
these four major nutrients are discussed.
One nutrient which has received widespread attention is
phosphorus. It is known that phosphorus can r r limiting to
phytoplankton and other organisms. Most of the phos^norus
in the aquatic environment is bound in the seaiments as an
insoluble phosphate salt with availability of insoluble
salts being influenced by both the physical-chemical
factors (2) and bacterial metabolism (3). As seen in
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Fig. 3, loss or precipitation ot phosphates to the seuiments
and solublization of insoluble phosphates from the sediments
and exchanqe amonq the various biologic communities, is
mediated in part by the bacterial community (U - 10), Three
general processes involved in phosphate solubility are the
direct metabolic processes involving enzymes, caroon dioxide
production leading to a lower pH, and organic acid
production (11 - 13). Inorganic phosphate is, in turn, used
by higher aquatic plants, zooplankton, and phytoplankton.
As with phosphorus, sultur is cycled by the microbiai
populations in t.he aquatic environment and has been linked
to decreased product ivity_o_f fish (see Fig. U) .
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FIGURE 3
PHOSPHORUS CYCLE
SOURCE (14)
Higher aquatic
plants
Wistes
Introduction
Water
Mud
Bacteria
phytoplankton
Soluble organic
phosphate
tn
Bacteria Inorganic
reaction
Loss to Permanent Sediments
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26
Sulfate can be stoichiometrically reduced to nydrogen
sulfide, which in turn can be oxidized chemically, in the
presence of oxygen, to elemental sultur. Elemental sulrur
in turn, can be oxidized to sulfate. A specific class or
bacteria, the anaerobic dissimilatory sulfate reducers, also
leads to the stoichiometric production of hydrogen sulfide
and consequent anaerobic environments. On the other side
the oxidation of elemental sulfur by Thiobacilli leads to
•t-he production of sulfuric acid and their metabolic activity
is evident in the acid mine drainage in certain areas or the
country.
Biological nitrogen cycling involves, as does tne
cycling of sultur and phosphorus, the transition o± an
elemental nutrient through various cnemical states. Fig. 5
is a schematic representation of the cycling of nitrogen.
It is convenient to initiate the consideration of the
nitrogen cycle at a point where fixation of gaseous nitrogen
occurs. Relatively few species of microorganisms populating
the earth are capable of metabolizing nitrogen from tne air
/
(16 - 19). Once fixed from the atmosphere nitrogen is
converted by a relatively few species of bacteria ana blue-
green algae to organic nitrogenous compounds.
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FIGURE 4.
THE SULFUR CYCLE
SOURCE (14)
T
REDUCED ORGANIC SULFUR
IN LIVING MATTER
Plants "^ Animals "^ Bacteria
Utilization of tulfote
(plnrts, microorganisms)
Sulfir oxidation
(colorless and photosynthetic
sulfur bacteria)
Bacterial decomposition
of organic manor
Desu If o vibrio
Desulfotomaculum
Oxidation of HjS
(colorless and photosynthetic
sulfur bacteria, or
spontaneously)
©
N)
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28
Subsequent to fixation the relative concentrations ot
the inorganic nitroqen compounds in water, i.e., nitrate,
nitrite, and ammonia, depend, in part, on the amount ot
oxygen available and the oxygen concentrations are dependent
upon the organic carbon load and seasonal variations in
solubility of oxygen in winter. Attempts to develop a
nitrogen balance in lakes and other aquatic environments are
hampered by the fact that there are several possible sources
for loss of nitrogen. For example, fixed nitrogen can be
lost via: (1) lake effluents; (2) loss of volatile nitrogen
such as ammonia and nitrogen gas; (3) denitrification by
certain microbes; (U) precipitation of nitrogenous compounds
into either permanent or semipermanent sediments; and (5)
removal of organisms by fishing, weed harvesting or otner
methods of fauna and flora depletion.
The biochemical mechanisms involved in denitrification
have only recently been elucidated in significant detail
(20 - 23). These reactions result in the conversion of
nitrate to, ultimately, nitrogen gas and are apparently
unique to a limited group of microorganisms.
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Figure 5
REVIEW OF THE NITROGEN CYCLE
SOURCE (14)
Htfecid Nitr«|tn
in wpiic Witltr
(Mottly Mrvkic)
to
o
ic and ilkilint)
\
"Nitiiliciliin"
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30
The carbon cycle is composed of an integrated network of
physically and biologically mediated pathways encompassing
the synthesis, degradation, and transformation of
innumerable simple and complex organic molecules {Fig. 6).
Superimposed on the carbon cycle are the controls exerted by
nutrient availability, and the fixation and evolution of
carbon dioxide. Various aspects of the organic carbon cycle
in the aquatic environment have been examined witn the
emergent principle that an overall balance between the
production, or synthesis, and decomposition of naturally
occurring substances exists in nature (24, 25).
Photosynthetic carbon dioxide fixation by green plants
is a major route by which carton enters the organic carbon
cycle. However, fixation by autotrophic bacteria adds to
the total carbon budget in the ecosystem (26, 27), Once
organic material has been introduced into the aquatic
environment the endogenous flora and fauna can either
utilize or contribute to, depending upon conditions, an
existing reservoir of organic material (28). Some of trie
ecological questions relating to carbon arise when
considering the microbe's direct relationship to carbon
cycling are: what effect does microbial synthesis of
complex molecules such as vitamins, amino acids.
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31
carbohydrates, and lipids have on the aquatic biota; wnat is
the contribution of bacterial biomass, a food source for
zooplankton; and what is the significance of microbial
degradation of suspended soluble or sedimented organic
compounds?
Direct and complex relationships between diverse
organisms have evolved based on the needs for various growth
factors. Examples of these relationships are seen in tne
association of various algae and bacteria in the marine and
fresh water environments (29 - 32). Also, the degradation
of complex, naturally occurring organic compounds such as
chitin are affected by the microbial species.
Microbial metabolic activity affects the cycling OE trie
four major inorganic nutrients under consideration. The
cycling of each of these nutrients - phosphorus, sulfur,
nitrogen, and carbon - is interrelated in that any
perturbation in one cycle has far reaching effects in the
other cycles. For example, it has been shown that tne
sulfate reducing bacteria are capable, not only ot nitrogen
fixation, but of degradation of carbon compounds to carbon
dioxide and also of effecting a solubilization of phosphate
as a consequence of precipitation of insoluble iron sulfide
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32
prpcipitat.es. This is but one example. Thero are inariy
examples of these interrelationships of microbial
communities with higher fauna 1 and floral communities and
with water quality.
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FIGURE 6
MICROBIAL CYCLING OF CARBON
BACTERIAL
DECOMPOSITION
FIXATION
GREEN PLANTS
CERTAIN BACTERIAL SPECIES
COMPLEX
MOLECULES
ALGAE
BACTERIAL
SYNTHESIS
VITAMINS
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3U
Section IV
POSSIBLE REMEDIAL MEASURES FOK RESTORING AND
ENHANCING THE QUALITY OF THE NATION'S PUBLICLY
OWNED LAKES
Lake restoration technology is in its infancy, only a
few lake renewal proqrams have proved successful, ana these
only on individual lakes. A method of lake rehabilitation
which may be hiqhly successful on a qiven lake, may oe
totally impractical or unworkable on another. Eacn lake nas
its own peculiar characteristics, differing from all others
geographically, morphologically, chemically and biologically
as well as in the nature of its problems. Consequently, it
is impossible at this point in time to recommend remedial
measures which will prove to be effective for all lakes or
even particular classes ot lakes. It is t.he responsibility
of lake managers to define the problems and to implement
rehabilitation or enhancement programs which are oest tittea
to the requirements of particular lakes on a case-by-case
basis.
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35
This section presents information on possible rei.ieaiax
measures which have been cr are presently being appliea in
lake rehabilitation prcqrams or in some cases are oeirig
evaluated in the laboratory. Many techniques are currently
in experimental stages on small lakes, and the results are
inconclusive at this time. Other techniques have met with
varying degrees of success on individual lakes, but tneir
applicability to other lakes is unknown.
Since eutrophication poses the greatest threat to the
Nation*s lakes, this report focuses primarily upon tnose
remedial measures which may be applicable to certain laK.es
displaying symptoms of accelerated or man-induced
eutrophication. Possible remedial measures for la*es
contaminated with industrial wastes including toxic
substances and hazardous materials are only briefly
discussed. Subsequent reports will deal with these problems
in greater detail. Solutions to problems associated with
.thermal discharges to lakes are not addressed in this
report. Thermal discharge control technology is to be
addressed in a forthcoming EPA publication as required by
Section 10U(t) of the Federal Water Pollution control Act
Amendments of 1972.
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The approach to the rehabilitation of deqra de.i ic».s.Ob is
fold: (1) by restricting the input of unaesirdL/ie
materials and (2) by providing in-lake treatment ror trie
removal or inactivation of undesirable materials.
Obviously, the only means of mair^aininq the; juulit/ 01 a
lake once dasired conditions are achieved, i:-3 i.y
restricting the input of undesirable materials. In
iakes reducino or ^liminatina the primary sources or waste
loading is the only restorative measure neeaea to acai^ve
the desired lev°l of improvement. Oner the source of
pollution is abated, natural flushing and dilution wit.i
uncontaminated water may result in substantial imt'rovcineiitJ
in the quality of the lake. However, in many lakco,
particularly in hypereutrcphic lakes with slow flushing
rates, in-lake treatment schemes may also he required bcrore
significant, improvements will he realizeo. In-lake
treatment alone without controlling pollutional intiows
cannot be termed a restorative measure as only tho b>mptoms
or products of eutrophication and pollution are treareJ ana
no permanent improvements in quality are achieved. In any
lake restoration program, controlling the input of '
undesirable meterials is the initial step towards p
lake rehabilitation; all ether remedial measures are
supplementary to this action.
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37
In the following discussion, measures which may be
effective in the restoration and enhancement of tne Duality
of lakes are addressed under tour irajor headings as ruliows
1. RESTRICTING NUTRIENT AND SEDIMENT INPUT
A. Point source nutrient removal and control
B. Nutrient diversion
C. Control of allocthoncus sediments
2. IN-LAKE TREATMENT AND CONTROL MEASURES
A. Dredqinq
3. Nutrient inactivation
C. Dilution and dispersion
D. Covering of sediments
E. Artificial destratification and
hypolimnetic aeration
F, Drawdown
G, Harvesting nuisance organisms
H. Biological control of nuisance organisms
I. Chemical control of nuisance organisms
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38
CONTROL AND REMOVAL OF HAZARDOUS SUBSTANCES
U. POSSIBLE LAKE PROTECTION MANAGEMENT CONSIDERATIONS
RESTRICTING THE NUTRIENT ANC SEDIMENT INPUT
Point Source Nutrient Removal and^Controj.
i
Domestic wastewater represents a siqriticant source of
aquatic plant nutrients and therefore is the source tnat is
often considered first for control.
Conventional waste -treatment systems usinq sedimentation
and activated sludge or tricklinq filters remove only
suspended and dissolved solids and a portion of trie
nutrients. Although these systems serve to reduce tne BOD
load to receiving waters, they generally remove less Lhari 50
percent of the phosphorus and nitrogen (33).
The technology is presently available to remove i;otn
phosphorus and nitrogen from vvastewater at a moderate cost.
Phosphorus removal efficiency of 80 to 95 percent can be
achieved by cheirical precipitation with alum, lime or ferric
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39
salts. Removal of ammonia and other nitrogen species can be
accomplished by ion exchange, ammonia stripping at ni.jn yii
in a gas stripping tower, breakpoint, chlorination or
bacterial denitrification.
Advanced wastewater treatment (AWT) for nutrient, removal
probably represents the best method currently available lor
curbing nitrogen and phosphorus input to waterways. An
obvious limitation of advanced waste treatment is its
inapplicability to the treatment of most wastes from non-
point sources. However, under certain circumstances entire
rivers which receive their nutrient loads from diffuse
sources may be treated prior to their entry into a lax.e. In
Germany, it has been proposed to treat the entire Wannoaca
River using iron to precipitate the phosphorus. Tne
Wahnbach, which forms the Wahnbach Reservoir, receives its
wastes primarily from agricultural runoff.
The storage and disposal of waste materials extracted in
advanced wastewater treatment plants add to the total
treatment costs. The concentrated sludge and liquid must be
disposed of in such a manner that the nutrients do not re-
enter a waterway. The practice of depositing sludge in
marsh areas and along waterways is ecologically unsound.
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40
However, the application of the sludge to cropland to
increase production is one beneficial means of disposal.
Information on the cost and efficiency of varicus
advanced waste treatment processes currently in use in the
United states is presented in Tables 1 and 2. Table 1
compares total costs and removal efficiency for various
nitrogen control processes. Table 2 presents information on
average costs of phosphorus removal based upon 1971 data
compiled by Cecil (3U). From an examination of tnese data
it is apparent that although some processes are more
expensive than others, in most instances for comparable
levels of nutrient removal efficiency, the cost ranges
overlap. The characteristics of the particular situation at
hand which influence the cost of the treatment process
include: (1) the existing treatment facility, (2) required
water quality standards, (3) use and character of the
receiving water, and (U) climatic conditions. Since
nutrient removal treatment systems are usually built as
modifications of existing plants, the most important single
factor influencing the selection of treatment processes is
the existing treatment facility (35).
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TABLE 1
Comparison of Nitrogen Removal Processes a/
rocess
Class
Removal Efficiency
Estimated Cost
C/3.785 ml
(0/1,000 gal.)
Wastes to he
Disposed of
Remarks
Armenia stripping
Ion exchange
(Clinoptilolite)
Breakpoint chlorination
Nitrification-Denitrification
Physical chemical
Physical chenical
Chemical
Biological
64-80
90-95
3.8-10
5.7-13.6
liquid
liquid
99
90
10.8-20.6
5.2-17.3
None
Sludge
Efficiency based on
ammonia nitrogen only
Efficiency and costs
depend on degree of
pretreatnent
Reouires strict
process control
Requires some chemical
addition and large
land disposal area
a/ Data supplied by the Advanced Waste Treatment Laboratory, National Environmental Research Center, Cincinnati, Ohio
~ and the Municipal Technology Branch, Technology Division, Office of Research and Monitoring, Washington, D.C.
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42
TABLE 2
Treatment Plant, Operatinq and Maintenance Costs for Phosnhornn Removal
Treatment Plant Costs a/b/
Plant Size
3,785
(1 mgd)
37,854 m3/dav
(10 mcid)
378,540 n3/day
(100 mod)
Building and Structures
Process Equipment
Installed
Lime
Aluminum salts
Iron salts
Capital Investment Costs in Dollars
15,000 40,000
45,000
35,000
35,000
150,000
96,000
85,000
90,000
410,000
300,000
250,000
Operatinq and Maintenance Costs in Dollars/day
Labor
Operating
Maintenance
Amortization
Lime
Aluminum salts
Iron salts
35
18
13.20
10.90
10.95
100
90
41.80
29.80
29.48
200
225
109.15
8f .50
74.80
Chemicals b/ and Sludge c/
Disposal Costs ~"
80% P Removal
Lime 3C.50
Aluminum salts 40.45
Iron salts 43.05
90% P Removal
Lime 6C.35
Aluminum salts 53.70
Iron salts 56.10
Total Daily Operating
and Maintenance Costs
80% P Removal
Liine 102.70
Aluminum salts 104.35
Iron salts 100.45
90% P Removal
Line 132.55
Aluminum salts 117.CO
Iron salts 120.05
329.45
382.G5
389.15
5B4.75
509.30
508.75
561.25
602.45
608.63
816.55
729.10
728.23
3,293.20
3,643.20
3,888.75
5,303.20
4,933.20
4,998.20
3,827.35
4,lr>4.70
4,338.55
4,837.35
5,444.70
5,498.00
a/ Source: (34)
B/ The use of polymers for improved coagulation is included in choriral costs
£/ Land disposal is assumed
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43
In this country there are currently about 1200
wastewater treatment plants, planned or in operation, wnich
incorporate some degreee or AWT technology. However, to
date there has not. been documentation evaluating AWT as <*
means of restoring a lake. The EFA program at Shagawa Lake
(36) will possibly be the tirst thorough evaluation
documenting restoration of a lake by nutrient removal
through AWT of municipal wastewater. Lake Tahoe and tae A^T
plant there have been studied for a number of years;
however, the plant effluent does riot enter Lake Tanoe but is
diverted to a reservoir outside the watershed.
Several advanced wastewater treatment plants are in
operation in Europe but data documenting the effects on iax.e
restoration are incomplete. Preliminary data on tne
Groifensee in Central Europe indicate that the phos^norus
content stopped its upward climb aftor an AWT plant was
built to remove 90 percent of the phosphorus froir. the Uster
municipal wastewater (37).
Other possibilities for removing nutrients from a point-
source include spray irrigation, scil infiltration ana
culturing and harvesting algae or aquatic plants. Spra>
irrigation of wastewater on land to facilitate the growing
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of crops results in two methods of nutrient removal. It
ties up nutrients, particularly phosphorus, in the soil, ana
it allows nutrients to be incorporated into a croL; tnat can
be harvested and removed from the watershed.
This technique is presently heincr evaluated as «
nutrient removal technique through an EPA grant at 1'lusK.etjon,
Michiqan.
Pennsylvania State University has shown that cro^s that
have been irrigated by wastewater effluent can suustantialiy
remove nutrients contained in the effluent. (38) . In the
upper 30.5 cm of soil the concentration of nitrate was
reduced up to 82 percent and phosphorus up to 99 percent.
Studies in Oklahoma showed that grasses grown in
hydroponic culture tanks removed appreciable nitrogen but
only slight amounts of phosphorus from secondary wastewater
(39). One drawback to the spray irrigation technique is
that, long term irrigation with water high in sodium or other
metals could render a soil unproductive it these materials
reach an undesirable concentration.
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45
Soil infiltration, whereby wastewater is allowed to move
through the soil, removes or qreatly reduces suspenued
solids, biochemical oxygen demand, microorganisms,
phosphorus, fluorides, heavy metals and other substances,
including nitrogen if the recharge system is properly
managed (UO). Peat is particularly good tor removing
phosphorus. In an EPA study (41) it was shown to remove 95
to 99 percent of the phosphorus from secondary wastewater.
Species of the bulrush, Scirjnis, have been used in tne
biological purification ot wastewater (42). Phosphorus and
nitrogen are readily taken up by these plants and periodic
harvesting of Scirjaus will remove the nutrients from tne
system. The use of Scir^ilS to facilitate wastewater
treatment is being evaluated in Germany.
The culturing and harvesting ot algae tor nutrient
removal have been evaluated. EPA is presently evaluating
this technique at Firebaugh, Califcrnia, to remove nitrogen
from agricultural return canals that enter San Francisco
Bay. in South Africa (43) culturing and harvesting algae
have been studied as a method of producing water suitable
for reuse from wastewater.
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46
Diversion ofters a possible restoration technique in
situations where the majority ot the incoming nutrienc luau
i? enterinn from specitic point, sources. It has oetm used
as a technique to control nutrient input from muni cipdli ties
located around the perimeter of lakes.
The major disadvantages include the following':
1) Monetary costs - the expense of installing tne
necessary collection system for many lakes may be
prohibitive.
2) Environmental costs - diversion ot untreateu sewage
from a lake to another waterway may result, in the
degradation ot that waterway and the substitution ot one
problem for another.
3) Lake morphometry - If the lake basin is shallow,
i
nutrient exchange between sediment and water may recycle
nutrients to the extent that no recovery is discernible.
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47
4) Ground water - If the around water inflow is
significant with respect to total hydroloqic budget dnu it
is high in nutrients, recovery will be very slew or no
recovery may occur.
5) Hydraulic residence time - The rate at wnica iiiga
nutrient water leaves the basin will affect eventual
recovery.
Case Studies:
1 . Lake Washington - Seattle^ Washington, USA^44 -
Lake Washington at. Seattle is a former oliqo«-rot,nic
which rapidly deteriorated to a state of eutrophy, bur. w;;icn
in recent years has shown definite signs ot recovery.
The lake lies in an elongate, steep-sided glacial trougn
with a maximum depth of 65.2 m, mean depth of 32.9 m ana a
surface area ot 8768 hectares (21,650 acres).
Prior to 1963, Lake Washington received heavy nutrient
loading from eleven sewage treatment plants discharging
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U8
directly into the lake. It is estimated that in 1957, 5o
percent of the phosphorus and 12 percent of tne nitrogen
entering the lake was from sewaqe effluent. Extensive
Oscillatoria rubescens blooms were observed in 1955
indicating considerable degradation of water quality. Tne
abundance of alqae was approximately 15 times greater in
1962 than in 1950. Secchi disc measurements had been
reduced from 3 meters in 1950 to about 1 ireter in 19b3,
196U, and 1965. Nutrient concentrations increased
dramatically. Phosphorus increased from 0.009 mg/1 in 19 J3
to 0.475 mg/1 in the 1960»s, and nitrate from 0.170 mg/1 in
1933 to 0.475 mg/1 in the 1960*s. Dissolved oxygen
concentrations reached zero in the deeper water strata lor
the first time in 1957.
A series of steps was instituted by Metro (Municipality
of Metropolitan Seattle) in the late 1950's to divert tne
sewage from Lake Washington and to build a series ot new
treatment facilities which would discharge into Puyet sound.
Estimated cost for the project was about $120,000,000. Tne
first, phase of the diversion was completed in 196J, at wnicn
time approximately 25 percent of the effluent bypassea the
lake. In 1965, the effluent volume entering the lake was
reduced to approximately 55 percent of the original load.
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U9
and by 1968, the project was complete vvith approximately 100
percent of the effluent diverted.
Improvement in water quality has been dramatic since
diversion was completed. Phosphorus concentrations in 19o9
were 28 percent of the 1963 values and nitrogen
concentrations were 80 percent of the 1963 levels- 3ecchi
disc measurements have increased froir, 1.0 m to 2.8 m.
Chlorophyll levels have decreased to approximately 15
oercent of the mean winter values tor 1963, and noxious
blooms of blue-greens have been eliminated.
Lake Washington has shown a significant improvement with
th*> diversion of spwacre. A reduction of 50 percent in tne
phosphorus loading has greatly decreased the algal growth
and a significant increase in transparency has occurred.
Dat-a indicate that phosphorus is the controlling element
wi+-h respect to algal growth in Lake kashingtor: anu tne
results of the diversion illustrate this in a dramatic
manner.
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50
2« Lake Sammamish, Seattle, Washington, USA (j*8]_
.The outlet of Lake Sammamish forms the inlet to trie
north end of Lake Washington, In 1968 the sewage was
diverted from Lake Sammamisn, but recovery has not been
observed. Approximately 65 percent of the total phosphorus
and 22 percent of the nitrate-nitrogen were diverted witu
the interception system. Surface nutrient concentrations,
algal activity, light penetration and hypolimnetic oxygen
deficits have not changed.
Although Lake Washington has shown a dramatic recovery.
Lake Sammamish has not. Proposed reasons for this include:
(1) a greater exposure of epilimnetic waters to sediment in
Lake Sammamish (65 percent more than Lake Washington), (^)
the lesser state of eutrophication of Lake Sammamish at the
time of diversion, (3) the possibility of funqi
(actinomycetes) complexing phosphates and removing tnem from
the system, and (U) ground water infiltration from urbanized
areas of the lake. No experimental work has been conducted
on the first three proposals but the fourth alternative is
unlikely because intensive monitoring of the tributaries nas
failed to detect abnormally high phosphorus concentrations.
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51
3. Madison Lakes, Wisconsin, USA (45, 46, 49, 50)
The city of Madison, Wisconsin is located between Lakes
Mendota and Monona, the first and second lakes in a series
of four on the Yahara River,
All of the Madison Lakes have a long history of algal
problems, but Mendota has been the least troublesome. Lakes
in this region are naturally productive, but the problems in
the Madison Lakes were attributed to urbanization.
In the early history of the city, Lake Monona received
the sewage from the city of Madison. As a consequence in
1912 algal growths had become so prolific that copper
sulfate was used to kill the algae, and in 1925 a regular
program of treatment with copper sulfate was established.
The condition of the lake deteriorated steadily. In 1928
the Nine-Springs plant was placed in operation and the
effluent from this operation was carried via Nine-Springs
Creek to the Yahara River downstream from Lake Monona.
Algal productivity in Lake Monona was not measured
directly, but the quantities of copper sulfate used to
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52
control algal growths may be indicative of the intensity of
algal crops. Since relocation of the plant, the amount of
copper sulfate needed to prevent obnoxious bloons has
decreased dramatically. A total of 1,579 kg (3,481 pounds)
was used from 1955 to 1963 as compared to 45,587 kg (100,500
pounds) used in 1934 only. A change in species composition
has also occurred. The algae presently inhabiting the lake
do not cause surface scums, thus the need for copper sulfate
has diminished.
The relocation of the sewage treatment plant did not end
the Madison Lakes' problems. Shortly after the effluent was
moved downstream from Lake Monona, the symptoms of
overenrichment in Lakes Waubesa and Kegonsa began to
intensify and copper sulfate treatment in large doses was
required.
The community eventually adopted a plan by which the
effluent was diverted from the Madison Lakes via the Badfish
River to the Yahara River downstream from the lakes. The
i
diversion project was completed in 1958. Since diversion,
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53
the condition of the lakes appears to liavo improved, out
Radfish River has deteriorated considerably.
It is difficult to relate the Madison Lake diversion
project to the Lake Washiqton case, because the Mauison area
is much richer in dissolved minerals than is the Lako
Washington area, and consequently the Madison Lakes are
naturally more productive. In addition the Madison LaKcs
are much smaller and much shallower than Lake wasnin«jton
(see Table 3) .
TABLE 3
PHYSICAL CHARACTERISTICS OF THE MADISON LAKES
Mean
Length Width «Area, . deptn, deptn,
Lake km (miles) km (miles) km (mi) m m
Mendota 9.5 (5.9) 7. U (U.6) 39. 4 (15.2) 2b.62 12.1
Monona 6.7 (4.2) 3.9 (2.4) 14.1 (5.U) 22.b7 8.4
Waubesa 6.8 (4.2) 2.3 (1.4) 8.2 (3.2) 11.16 4.9
Kegonsa 4.8 (3.0) 3.6 (2.3) 12.7 (4.9) *.b8 4.7
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5U
U. Red Lake (Rotsee)t Lucerne. Switzerland (U5)
Sewaqe was diverted from Red Lake (Rotsee) in 193J, but
the lake continued to produce nuisance quantities or aigae.
The reasons for the lack of improvement in Red Lake
following diversion are attributed to the lake*s small size
and .the considerable drainage it receives from fertilized
and cultivated cropland.
5. Lvngby-So, Copenhagen. Denmark (45)
The sewage was diverted from Lynqby-So in 1959 and
productivity, as measured by the rate of photosynthesis,
decreased markedly for the next four years. The submerged
rooted aquatic vegetation disappeared from the lake after
1956 presumably from shading by algae, but the aquatic
macrophytes are now becoming reestablished. It appears in
this case that recovery began immediately.
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55
6- Stone Lake^ Michigan, USA (51)
Stone Lakp which has a surface area of 56.6 hectares
(140 acres) began to receive secondary sewage in 1939. fne
treatment plant was replaced in 1965 and the treated wastes
since then have been disposed of outside the drainage Dasiri.
The only remaining sources ot pollution are a few nousenold
septic tanks located on the periphery of the lake. The lake
has shown little response to the cessation of nutrient
influx from the treatment plant.
Several reasons are suggested for the failure or tne
remedial technique. Although over 95 percent of tne
phosphorus and 50-75 percent of the nitrogen were removed,
some pollution is still entering the lake (organic
materials). Because of the relatively shallow morphology
(mean depth 6.1 m.) sediment-water nutrient interchange may
be responsible for recycling previously deposited materials.
Further, hydraulic retention time is of such a magnitude (11
years) that insufficient time has elapsed to observe
significant improvement in water quality.
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56
Lake_Anjiecy>x_I!i:d_ncO
Lake Anriecy was classified in 1937 as "becoming
eutrophic". Conditions became more pronounced with time
because of human waste disposal to the lake. Low aissolvea
oxygen became the norm and species composition of tne
phytoplankton indicated an advanced eutrophic state during
the 1960's. In 1961, a diversion system was begun. By 1971
approximately U4 percent cf the population around tn-a
periphery of the lake was using the system.
Changes in algal composition indicate that the water
quality of the lake is improving, tut the studies nave not
been carried on long enough to determine the long term
effect.
8• Diamond Lake, Oregon, USA (53)
A sewage interceptor system has been installeu around
one-half the periphery of 1,9ttU hectare (U,800 acre) Diamonu
Lake. The lake is primarily used for trout fishing, and
extensive camping, lodge and summer home facilities are
located around the circumference. The U. S. Forest Service
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57
installed a waste collection system to replace existing
septic tank systems in 1971, but it is not as yet tuliy
operational. Studies have been made to obtain background
data on the chemical, physical and biological
characteristics of the lake. These will be monitored in the
future to determine changes in water quality.
9a Lakes Teqernsee and Schlicrsee (5U)
Sewage diversion (finished 196U/65) from two Bavarian
lakes (Tegernsee and Schliersee) resulted in a reduction or
the phosphate load to the lakes to about 10-20 percent or
the former amount while nitrogen income was diminished to
about 25-UO percent. In 1967 improvement was observed,
especially with better hypolimnetic oxygen conditions at
summer stratification. Subsequent years, however, showed a
relapse in the highly eutrophicated Schliersee to oxygen-
free hypolimnion again, while improvement at the 1'egernsee
was more or less maintained. Intensive remobilization of
nitrogen and phosphorus from lake deposits permanently
increased nutrient levels in the Schliersee up to 1*70. A
partially meromictic (permanent stratification) situation
seems to be mainly responsible for this process. Different
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58
circumstances which may promote or restrain improvement
after sewacre diversion include hydroloqical and climatic
conditions, progress of eutrophication at the moment of
sanitation, and intensity of nutrient-turnover.
Notwithstanding eutrophication parameters, sewage diversion
has removed primary pollution of *"-he lakes and their
tributaries which is of great importance for their
recreational function.
Control of Allochthonous Sediments
Sedimentation of lakes and reservoirs is a major factor
restricting the available acreage of the Nation's
recreational waters. In terms of volume, sediments are the
greatest pollutant.
Sedimentation rates in lakes and reservoirs can
freguently be retarded by prudential land use management
practices within the watershed. Construction and logging
activities should shun the steepest slopes, arid projects
which denude the landscape should be timed to avoid seasonal
rainy periods. Agricultural practices such as strip
cropping, contour plowing, and proper grazing practices
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59
prevent rural erosion and con sequent sed iron tat ior in
streams and lakes. Terraced hillsides and banlrs of
watercourses stabilized by riprap or gabionr, are also
effective erosion preventive reasnres.
Sedirent Traps
Gedirents ray sonetires be trapped before they enter
lakes and reservoirs by filter darns and. desilting basins
installed dov.T.strean froii all larae cleared areas and other
sources of silt. Detailed descriptions of scdirent traps
and their use as well as other effective srdii ont controls
may be found in the publications by Throrson (55) and the
national Association of Counties Research Foundation (56).
Analysis of Sedirent Transport
The mechanics of sedirent transport have b
extensively studied and hydraulic and nathenatical r,od<=l
studies of bedload and suspended load transport are
described by Eogarci (57) . Three stages of statistical
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60
analysis can be recognized in sedimentology (56). Tne first
stage is descriptive statistics in which the sample is the
object of interest. The second stage is analytical
statistics in which the population is the object of
interest. The third stage is the application of stocnastic
process models in which the objective is to discern the
probabilistic elements in sedimentary processes. Krumbein's
paper, as abstracted in Selected Water Resources Abstracts
by the U.S. Department of the Interior, states (58),
"Stochastic process models thus provide one way of examining
sedimentary processes through time or over an area. In
conjunction with deterministic models they provide a
framework for exploring the underlying physical, chemical,
and biological controls on sedimentary processes and
deposits...." Using turbulent diffusion theory (59) a rion-
steady-state model was developed for sediment transport.
Cost Effectiveness Models
The economic benefits to be gained by controlling'
erosion and sedimentation are compared to the control costs
in a cost effectiveness study. Such a study on the Seneca
Creek watershed, near Washington, D.C. (60) compared cost to
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61
effectiveness and damaqe values for many sediment control
methods. Present control practice includes sediment oasins,
diversion basins, level spreaders, grade stabilization
sr.ructures, sodded ditches, seeding, and straw muicn t-acKed
with asphalt or disked. The average conventional system is
estimated to cost $2780/hectare and to control 91A of cne
potential erosion. Control systems incorporating large
sediment basins can boost control to 96% at less total cost.
Economic aspects ot sedimentation are also discussed £>y
Maddock (61).
IN-LAKE TREATMENT AND CONTRCL MEASURES
Dredging
Many lakes have suffered the consequences of filling arid
nutrient enrichment as the result of allochthonous materials
entering from the watershed. Highly eutrophic lax.es also
receive large amounts of autochthonous materials resulting
from massive algal populations. Much of the organic
material entering the system will not be decomposed oecause
of the low oxygen conditions in bottom waters associated
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62
with increased productivity. The eventual resul^ is an
accelerating rate of sedimentation and a fillinq or tne iakt1
basin.
Dredging has thus been proposed as a possible remedial
technique. This would serve to reprove the sedimf-nt build-
up, thus increasing the depth of the lake, and removing a
potential nutrient source. A large number of lakes nave
been dredged but no information is available on the cnemical
or biological effects.
A number of disadvantages are obvious with respect, to
this technique:
1) The relatively high costs cf dredging operations
may make this technique prohibitively expensive on large
lakes.
2) The dredging operation may release nutrients from
the sediments, making them available for reinvolvement in
the food web. The nutrient content of many sediments may
remain high at considerable depths, making it impossible to
reach a low nutrient level in the sediment.
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63
3) The elimination of shallow zones which maintain
large macrophyte beds, may result in a considerable increase
in the algal populations. The nutrients formerly tiea up in
macrophyte biomass could become available for algal growcri.
The result may be the substitution of one problem for a
second.
U) Turbidity resulting from the dredging process may
persist for a considerable time during and following
dredging.
5) Disposal of the dredged spoils economically is
often impossible. Sediments iray prove unsuitable for
agricultural purposes and in such a case, could be used ror
land fill only.
6) Interstitial waters contained in sediments are
frequently high in nutrients, consequently, disposal of tne
sediments must be in such a manner that leeching of nutrient
rich waters back to the lake is prevented.
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Case Studies:
1 • Lake Truminen, Vajko, Sweden _ [62J.
Lake Trummen is a shallow (1.1rri mean depth) small (1.0
2
km ) lako located in central south Sweden. The IdKe is one
of a series of oligotrophic lakes, indicating that
Trummen was also once oligotrophic. Waste water has entered
the lake since the turn ot the century resulting in a nignl>
eutrophic condition for many years. Studies indicate that a
20 cm layer of black, hiqhly organic qyttja has been
deposited since human habitation Legan around the laKe.
Plans were instituted in 1966-67 to develop some type ot
restoration program. The final decision has been to dredge
to a depth sufficient to remove the recent gyttja deposits,
and to dispose of these materials in bay areas of tne lake.
2
An estimated 600,000 n\ of sediment will be removea. Tne
water released from the sediments upon their deposition on
land will be treated with aluminum sulfate to remove
i
phosphorus before it is allowed to reeriter the lake. /
r
The Lake Trummen study is extremely comprehensive,
involving individuals from at least sixteen disciplines
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65
relating to water quality management. Data have been
collected for two years prior to th<=> study, and wiii ne
collected during the 2-year dredging operation. Thu
will be monitored for 8 years after completion or t-ae
dredging. Dredging operations were to begin in 1-J70, out. no
information is yet available.
2-
A suction type dreage was used to remove silt rroui
eutrophic Lake Herman. Analytical results in.iicat.ei cnac
water trom the drela^d material when it returned to tae iaKe
was lower in pH and total phosphates, and almost as cleat us
the lake water. Total orthophosphate-phosphorus i
dramatically in the lake water (approximately dou^
during dredging, but the concentrations of the o
nutrients remained at approximately the same
The following synopsis is taken from Technical Bulletin
Number U6, Inland Lake Drodging Evaluation, Depart :n^at ot
Natural Resources, Madison, Wisconsin (6U) . Very general
data are presented and none ot the lakes appear to have ueen
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66
investigated to determine water quality changes associated
with the dredging operations.
3. Wazeecha Lake^ Wood County, Wisconsin USA
The upstream end of LaKe Viazeecha, a 60 hectare (148
acre) impoundment of Buena Vista Creek* was dredged by trie
County over a four to five-year period. The dredgeu area
Q
was deepened by 1.2 to 1.5 m by the removal of 133,530 m° oi
sediment. The total cost of the operation, including tiie
purchase price of a second-hand 19.6 cm hydraulic cutternead
dredge was $66,859, at a unit price of $0.50/m^ (4>U. Jd/yd^) .
The dredged spoil was pumped onto the shoreline, improving
the conditions of the shoreline. One area was diked off and
filled, and a new park was created on the fill.
^- North Twin Lake. Calhoun County, Iowa USA
North Twin Lake, a 207 hectare (510 acre) lake in the
predominately agricultural plains country of west central
Iowa, had undergone rapid sedimentation resulting from
severe bank erosion and sheet erosion from the surrounding
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67
farmland. The lake had been tilled with as much as four
meters of sediment, reducing the lake depth to 0.6 to 0.9 in.
Dredginq first beqan in 1940 when 55 hectares (13b acres)
were dredqed to a depth ot U. 3 to 5.5 n-. Dredging was tneri
discontinued until 1960 when five dredqing contracts were
let to private contractors. Durinq the 1960*s the entire
lake beyond U5 m from the high water line was dredged to a
depth of 3.7 to U. 3 IT, removing 1,S23,U98 m^ of sediment.
The project was completed in 1969 at a cost, of $934,931.
The dredging was done by two contractors, one using a JO.5
cm and the other a 35.6 cm cutter head. The contractor using
the larger cutterhead excavated approximately 0.6 as much
material in a period of U months as the other contractor did
in six years, Kis total unit costs, including dike work,
were estimated at $0.52/m^ ($O.UO/yd^) of excavated
material, whereas combined unit costs for both contractors
3 ?
averaged *0.61/m ($O.U7/yd ). The unit costs do not
include administrative and engineering expenses.
Benefits to the lake, other than increased water depths,
have not been defined as yet.
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68
o
5. Lake Ceorge and Lake Sisseton, Fairmont, Minnesota USA
Lake George and Lake Sisseton are in a chain of five
lakes located within Fairmont, Minnesota. The city draws
its municipal water from these lakes, and their eutrophic
conditon was contributory to hirrh water treatment plant
operating costs and a warn municipal supply. In 19^6 the
city of Fairmont purchased a 30.5 cm portable hydraulic
cutterhead dredge and appurtenant equipment at a cost of
about $175,000 for the purpose of dredging the entire, chain
of lakes. To date only Lakes reorge and Sisseton have? been
dredged.
Prior to dredging, water depths in the lekes averaged
1.8 to 2.0 IP. The lakes were dredged in all areas beyond 4f>
m fron the high water line, sloping down to a maxirun depth
of 7.6 n or until a hard suhstrata was reached.
Dredged materials from Lake Sisseton were deposited on
an adjacent city-owred 69 hectare (170 acre) fan". The
disposal site is sufficiently larae to pemit adernato
settling so that the dredger. v;ater rkich returns to the lake
has a very lov/ suspended sclids content. The natcrirl
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69
dredged from Lake George was pumped to a different disposal
site which is presently being developed into a park.
q
It is estimated that 382,328 m of sediment are dredged
yearly at a cost of $35,000 to $50,000. Unit costs ot
dredged materials including engineering and administrative
costs, but excluding disposal site costs are estimated at
about $0.13 to $0.16/m3 ($.10 to $.12/yd3).
Dredging is part of an overall lake improvement program
being undertaken in these lakes. A complete sanitary sewer
system was also installed, and the combined effects have
reportedly been a marked improvement in water quality
although no quantitative data are available to support this
contention. The benefits derived from the total project
include: greater water depths and volume, lower water
temperatures, habitat improvement for fish and desirai>ie
aquatic organisms, a general increase in recreational value
and reduced water treatment costs.
Additional information is given for several otner la«.es
which have been dredged, but the atove examples are
representative of hydraulic cutting head dredging
experiences in the Great Lakes Region. A survey of
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70
inland lakes and ponds indicated that contract unit costs
will usually vary between $0.59 and $0.98/nr ($0.45 and
$0,75/yd^) When all costs are considered. The major factors
determining costs are : 1) the project size, 2) tne type or
material to be excavated, 3) distance to disposal sites, and
U) the availability of properly equipped dredging
contractors. Such factors as obstructions in the lakes such
as tree stumps and boulders, purchase cost of disposal site
(if necessary) and experience of the contractor can also
influence total costs.
There is no information available on the total
ecological effects of dredging upon lake environments or on
the water quality. Complete biological, physical and
chemical assessments of pre and post dredging conditions
need to be made on several lakes with varying
characteristics before the benefits derived from dredging
can be thoroughly evaluated.
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71
Nutrient Inactivation
It has become apparent after some nutrient diversion
studies that nutrients may remain in the water tor several
years an 3 noticeable improvement in water quality may oe
delayed. This seems to be particularly true of laxes wnicn
have practically no water flow- through tc replace tnat
which is high in nutrients. A possible alternative to
simply allowing the lake to remain in a highly eutrophic
state, is to attempt some method of nutrient inactivacion.
This process can be defined as the adding ot some type of
material that will bond with, adsorb, or otherwise
immobilize necessary algal nutrients, thus preventing tnein
from being utilized by these organisms tor their growtn.
Present studies have been directed toward the most
common growth limiting nutrients, phosphorus and nitrogen.
Phosphorus removal has been used in field studies on tnree
occasions, and some work has been done on a laboratory scale
using ammonia ion exchange resins.
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72
Many problems remain to be answered before this
technique can be considered operational. A few ot tae more
obvious potential problems are listed below:
1) The relatively high expense of treating the ooay of
water may be prohibitive. Materials may not in tnemselves
be overly expensive, but manpower necessary for application
and transportation costs may be considerable.
2) Possible toxic effects ty the introduction of an
excess of a metal used as a precipitant may have toxic
effects on the biota.
3) Adverse biological effects may result from trie
formation of a floe. The material used may be non-toxic*
but the floe could conceivably suffocate aquatic organisms
by interfering with their respiratory mechanisms. it is
also possible that the floe material resting on tne
sediments could interfere with the benthic ecology 01 the
system.
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73
U) In order to obtain maxirriurr effectiveness, it. may be
necessary to either raise or lower the pi: of the system,
which could have serious biological consequences.
5) The addition of certain salts, such as sultatea and
chlorides, may increase the conductivity of t.he water to an
unacceptable level. In the case of sulfate, if tne
hypolinmetic waters should become anaerobic after treatment,
reduction of the suitate would lead to the release ot
hydrogen sulfide.
6) Little information is available on the etfective
duration of the treatment. Wind action, continued inflow ot
nutrients, bacterioloqical and benthic organism activity are
a few of the phenomena which could possible influence tjne
longevity of treatment effects.
7) The time of application of the inactivent may be
critical; it may be necessary to apply the material when the
maximum nutrient content is present in the water.
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7U
Case Studies:
^- Lake Langsjon, Stockholmj Sweden (65. 66)
Lake Langsjon is a shallow (max. 3 m depth) , J5 nectare
(86.5-acre) lake which has received municipal waste, ^ear
the end of April 1968, 30 metric tens of aluminum suitate
were added in an attempt to inactivate phosphorus. The
final aluminum concentration was about 50 mq/1 of lake
water. Immediate results included an increase in seccni'
disc measurements from 50-60 to 250 cm, a reduction in total
phosphorus by approximately 50 percent ana a reduction in
phosphate phosphorus by a factor of 12 (60 to less cnan 5
uq/1). Total phosphorus increased during 1968, but a
concomitant increase in "thero-stalle" coliform bacteria
indicated that municipal sewage was enterina the lake.
During 1969-1970, there was an increase in phosphorus levels
during winter stagnation.
In May 1970, the lake was again treated with J2 metric
tons of aluminum sulfate. Total phosphorus values were
reduced by approximately two-thirds (170 ug/1 to 50 ug/1) .
During the summer of 1970, the phosphate phosphorus remained
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75
about 30 ug/1, sliqhtly above the levels encountered the
previous summer.
The investigators concluded that the aluminum suit ate
was effective with respect to total phosphorus reduction.
There was also a slight improvement in dissolved oxygen
conditions during winter stagnation: The period between tne
formation of the ice cover and the development of anaerobic
conditions was extended. They concluded, however, that the
effects of aluminum sulfate are net long lasting. A
substantial increase in both phosphate phosphorus arid total
phosphorus concentrations occurred during the period of
winter anaerobic conditions.
Following treatment, phytoplankton remained aoout tne
same with respect to total number of organisms but tuere was
a change in species composition, with a general reduction in
the proportion of blue-greens. No adverse effect, was noted
on the other biota, although little guantitative worx. was
done to verify this.
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76
2- Horseshoe Lake. Manitowoc Country, Wisconsin USA (b7)
Horseshoe Lake, an 8.9 hectare (22 acre), 16.7 m deep,
eutrophic lake in east-central Wisconsin was selected for
treatment and evaluation. The Lake was treated in May 1970,
by distributinq 10 metric tens of slurried alum in tae top
60 cm of water. Alum concentrations in the treated volume
were about 200 mq/1 (18 mg Al/1) , which, based on laboratory
testing, resulted in inaxirrum phosphorus removal with minimal
ecologic risk. The results of the treatment include: (1) a
decrease in total phosphorus in the lake, during the summer
following treatment, (2) no large increase in total
phosphorus in the hypolimniori during the following two
summer stratifications, (3) seme increase in the
transparency of the water during the summer following
treatment, (U) a short-term decrease in color, (5) an
absence of the nuisance planktonic algal blooms tnat naci
been common in previous years, (6) marked improvement in
dissolved oxyqen conditions, especially during the toilowing
two winters, and (7) no observations ol adverse ecological
i
consequences. Manpower, equipment and cost information are
summarized in Table U.
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77
TABLF 4
Summary of Manpower, Basic Equipment and Costs for Alum
Treatment of Horseshoe Lake, Wisconsin. I/
Samplincr
Analyses
Staff
Chemicals
Labor for Treatment
Iter
8 man hours per trip @ $5.00/hour
270 miles round trip @ $3.00 day
+ $O.C/mi.
12 samples per trip @ $30/sample
1 professional
overhead
10.88 Metric Ton Alurr @
$66.18/metric ton (12 ton @$60/ton)
Delivery to site
12 man days @$40/day
+ expenses
Costs 2/
S
s
R
S13
S 7
$
fi
$
$
40.00
19.20
360.00
,000.00
,300.00
720.00
180.00
480.00
100.00
Equipment List
2-18 ft. workhoats
2-10 ft.x20 ft. baroes
4-outboard motors, 18-25 hp
1-amphibious truck, 21/2 ton,
DUKW-353
4-gasoline driven pumps
1-4,000 watt generator
2-electric pumps
3-electric mixers
4-55 gallon slurry tanks
2-200 gallon slurry tanks
Piping, valves, hose, plastic
tubing, marker flags, gasoline,
plastic tarp, rope, dust masks
essentially all
onuiprent was
on loan
I/ Source: (67)
Many of the costs associated with this treatment are entirely
dependent on local salary levels, distances to site, sampling plan,
magnitude of treatment, and local availability of eouiprent.
In essence, treatment costs must be estimated for a specified
situation.
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3. Clines Point—Oregon USA (68)
A 0,4 hectare (1 acre) tarm pond with an average
of 2.4 m was treated with a neutralized solution o± sodium
aluminate. A concentration of 10 mg Al/1 (3 mg/1 NaAl02)
was achieved by the adoption of 227 kg of sodium aluminate.
The aluminum compound was neutralized with hydrochloric acid
prior to its application to form an aluminum hydroxiue floe.
The first year's results were encouraging. Total
phosphate, ammonia, total kjeldahl nitrogen, iron and
manganese remained lower than in previous years, and tue
algal standing crop was reduced. A shift in dominance from
blue-green to green algae was no-ted. Dissolved oxygen,
transparency and pH also indicated a significant improvement
in water quality.
Costs excluding labor were $100 for 227 kg ot sodium
aluminate and S60.00 for the hydrochloric acid. It required
five people one full day to treat the pond.
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*• Twin Lakes. Ohio: Stone Lake, Michigan USA
There are presently two demonstration grants funded by
EPA which anticipate the use of nutrient inactivation as a
lake restoration tool. The one project at Twin Lakes, Ohio
will combine nutrient diversion and nutrient inactivation.
Nutrient diversion is presently being undertaken and plans
are to treat the lakes with alum (aluminum sulfate). The
other project at Stone Lake, in southern Michigan, will
probably utilize fly ash and lime, in anfattempt to
precipitate the phosphorus as well as seal the bottom (5 cm
layer of fly ash in the deeper areas). Laboratory studies
have been encouraging using this technique, but the possible
hazards must be weighed against anticipated benefits when
considering the application of fly ash to lakes.
Many metals have been suggested as possible nutrient
inactivation materials. Lanthanium and zirconium nave been
investigated in the laboratory by the National
Eutrophication Research Program, EPA, with varying degrees
of success. Other suggested metals include iron, calcium,
activated aluminum, bauxite and several of the rare eartns.
Clays which would serve as adsorption sites for the
phosphate and bottom sediments have also been suggested.
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80
These would include such substances as bentonite,
montmorillonite and kaolinite. Polyelectrolytes are also
feasible but their cost is so qreat that it may be
prohibitive. Materials such as straw and sawdust have also
been used but the eventual decomposition of these materials
would be expected to create severe problems. Their use
would be highly questionable. Another possibility is the
resuspension of low nutrient bottorr sediment whicn would
absorb phosphorus as it resettled through the water column.
Nutrient inactivation would have to be evaluated on a
lake-to-lake basis. No universally acceptable substance has
been discovered which could be acceptable under all
environmental conditions. Because the technique represents
the addition of a foreign material to the water it should be
used very carefully. Long term effects on the biota or
water chemistry have not teen determined tor any ot the
substances listed above.
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81
Dilution and Displacement
The water quality of some lakes can re improved cy
diluting or replacinq the existing water with water ot a
higher quality. In usinq this method the replacement wat^r
must be readily available and there must he a convenient and
acceptable means of discharging lower quality water. rtater
replacement can be done in one of two ways: (1) uy
introducing high quality water directly into the ia*e, tnus
displacing an equal volume ct lower quality water or (2) b>
removing a given volume of the existing water and replacing
it with water of higher quality.
Case Studies
1. Green Lake. Seattle, Washington UgA_J69j.
The displacement technique has been successfully
employed in Green Lake, located in Seattle, Washington.
Green Lake is a 104 hectare (256 acre) , nat.urally
eutrophic lake, with an average water depth of 3.8 in.
Sedimentation has been rapid in Green Lake, with an
estimated two-thirds of the volume of the basin filled with
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82
sediment by the early 1900*s. The present rate ot
sedimentation is about 0.9 cm per year, practically all of
which is autochthonous organic matter. During the summer,
mixing of the entire lake is complete except for a very
small portion within the confines ot the 6 m contours, at
which depth thermal stratification persists.
It is estimated that Green Lake has been eutrophic tor
7,000 years. The blue-green algae production is very hign,
and rooted aquatic plants are abundant throughout the
littoral zone which comprises much ot the total area.
Herbicides are applied periodically to control rooted
vegetation.
In 1962 water was diverted to the lake from trie city*s
municipal supply for the first time. Between 196^ ana 19t>8,
the equivalent of approximately eight lake volumes of water
have been flushed through the lake.
A comparison of pre and post flushing data indicates
that substantial changes in water quality have occurred
following the addition of dilution water. Phosphate levels
have dropped considerably, particularly during August and
September when blue-green algae growths reach their peaks.
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33
Decreases in nitrate nitroaon were even rore pronounced,
v;ith the naxinun discrepancies occurring during r.idsumer.
Since dilution definite chancres in the species
composition of the phytoplankton have been observed. The
bluo-green alrrae v/hich, in 1959, were doninant durina all
nonths of the year, were the rest proninant form during only
5 or 6 months during 1905 and 19CG. There has also } een a
shift anorignt the blue-areen alrrae to those species wbich
are al^le to fi:: gaseous nitrogen. For e;:anple,
Aphanizonenon flos-aruae \;liich v;as the najor nuisance alga
during 1951 has all but disappeared fror« the laJ^e, and
Anabaena cirinalis and Gleotrichia echinulata have increased
in abundance.
further investigation of the Green Lal'e situation ir;
continuing, and atterpts are heing rade to develop a Vinetic
r.,odel that can be used in developinc sinilnr prograns
•
elsewhere.
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84
2 . Snake Lake, Viisonsin USA
The water removal /re fill technique has been carried out
at Snake Lake, Wisconsin. In the. summer of 1970 about tnree
lake volumes of water were pumped and deposited on land
above the lake. Nutrient-poor water from contiguous cjrouna
water aquifers and precipitation were allowed to replace tne
removed water. In the fall phosphorus concentration was
half that of the previous years. The lake nutrients and
other effects continue to be monitored.
Additional dilution and dispersion experiments have been
proposed at Moses Lake (71) and Vancouver Lake (72),
Washington, and at Lake Pled, Yugoslavia (73).
Covering of Sediments
Covering of bottom sediments with sheeting material
(plastic, rubber, etc.) or particulate material (clay, tly
ash, etc.) can theoretically perform tvo functions in
restoring eutrophic lakes. First it can prevent the
exchange of nutrients from the sediments to the overlying
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85
water, and second, it can prevent or retard the
establishment of rooted aquatic plants.
One problem encountered when covering sediments is the
ballooning of sheeting, or rupturing the seal of particulate
material, when gas is produced in the underlying seuiments.
For particulate material, the small sizes whicn have
relatively low effective specific gravity (i.e. clays, tly
ash) appear to be best suited for sediment covering.
Materials of larger size (sand and silts) tend to sink below
flocculant sediments. Sands and silts, however, can oe
effective in areas where the sediments are more
consolidated. Materials such as Kaolinite- arid fly asii,
which have a high water soluble lime content, have tne aciaea
advantage that they will remove phosphate from the water and
carry it to the bottom in a relatively insoluble torrn.
*
Covering of sediment to improve lake conditions has been
done at Marion Millpond, Wisconsin (70). About 12.1
hectares (29.9 acres) of this 44.5 hectare (69.9 acres) .Lane
were physically treated by (a) sand blanketing, (b) scraping
of overburden to a sand substrate, and (c) covering tne
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86
sediments with black plastic sheeting anchored with Sana and
gravel.
The University of Notre Dame is evaluating fly ash to
cover and prevent sediment nutrients from entering the
overlying waters (7U). This appears to have promise not
only as a barrier between sediirent and water but also as a
material to remove phosphate from the lake during
application.
The possible consequences resulting from the application
of fly ash to lakes as a sediment covering agent onould be
thoroughly evaluated prior to application. Fly ash
frequently contains numerous impurities including several
heavy metals, phosphorus, boron, radioactive wastes ana many
others. The damage resulting frcm "treatment" with fly ash
could conceivably offset any benefits.
Artificial Destratification and Hypolimnetic Aeration
Possible techniques for altering the water quality in
eutrophic lakes include artificial destratification ana
hypolimnetic aeration. These methods are of particular
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87
value in improving the water quality of lakes in whicn trie
hypolimnion is void of dissolved oxygen and thus
uninhabitable by aerobic organisms. The effective actions
of both of these processes are to increase oxyqen
concentrations in the water, promote the oxidation of
reduced organic and inorganic substances and enhance biotic
distribution. It must be emphasized, however, that tnese
techniques are palliative in nature, i.e., they will not, in
themselves, restore a lake. Aeration techniques generally
treat the symptoms of over fertilization rather than tne
source. Permanent restoration will be accomplished only be
removing or significantly reducing the primary nutrient
inputs to a lake. Following such a reduction aeration
methods may be effective in increasing the rate or recovery.
Artificial destratification of a thermally stratitied
lake is most often accomplished by injecting air into tne
water at the deepest point. As the bubbles rise to tne
surface vertical water currents are generated. The colder
and denser bottom water mixes with the warmer surface water,
sinks to a level of equal density and spreads out
horizontally. Oxygen is added to the water directly from
the compressed air as well as by contact with the atmosphere
and by photosynthesis of aquatic plants. As the mixing
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88
process continues, complete circulation is achieved and the
lake approaches an isothermal condition in which the water
temperature and dissolved oxygen level are approximately
equal from top to bottom. Likewise, with elimination o±
distinct epilimnion, metalimnion and hypolimnion zones, the
whole watermass becomes inhabitable by the biota. The time
required to reach this condition depends on the time of
year, size of the lake, degree of stratification and method
of air injection.
Artificial destratification may also be accomplished by
utilizing a mechanical pump to move the bottom water to the
surface. Although this technique does effect complete
mixing, it does not afford the advantage of oxygenation
directly from the air bubbles produced by air diffusion
systems.
In contrast to artificial destratitication, the process
of hypolimnetic aeration does not disrupt the thermal
stratification of a lake. The aerator consists or a large
diameter pipe which extends from the lake bottom to aoove
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89
Air is released throuqh a diffusor near the bottom of trie
pipe. As air rises in the pipe, water is drawn in tnrougn
the bottom ports. Oxygen diffusion occurs as the water
rises to the surface with the air bubbles. At the top oi
the pipe the air escapes into the atmosphere. The water
sinks to the outlet port where it flows back into the
hypolimnion. After the establishment of a hydraulic head in
the pipe, water flows directly from the inlet to the outlet
ports without rising to the surface. Hypolimnetic water,
therefore, is aerated but not significantly heatea or mixed
with epilimnion or metaliirnion water. Thus, the aissolved
oxygen level of the bottom waters is increased, but tne
integrity of the thermal strata is maintained, witn tne warm
water of the epilimnion overlying the cold water of tne
hypolimnion.
Advantages
The benefits of artificial destratification and
hypolimnetic aeration are most pronounced on eutrophic lakes
which undergo oxygen depletion in the hypolimnion, in
contrast to oligotrophic lakes which never become oxygen
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90
deficient. The changes in water quality which are induced
by these techniques include the following:
1. Due to the increased oxygen levels in the
hypolimnion, there is a reduction in the anaerobic release
of nutrients from bottom sediments (75). This results in a
general decrease in productivity of the body of water.
Also due to higher hy^olimnetic oxygen levels, oxiaation
of reduced organic and inorganic iraterials occurs in trie
water (77). This is particularly important when the lake
serves as a raw water supply. In such cases, the need for
specialized water treatment processes to remove taste and
odor carrying materials such as iron and manganese is
obviated.
2. The range of benthic populations is extended into
areas which were once anaerobic (75). An increase in the
number of fish and a shift to more favorable species could
result due to the greater availability of food organisms
(75, 78).
3. Favorable changes in algal populations occur with a
decrease in undesirable blue-green species and an increase
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91
in green algae species (79). This is a result of the
continued movement ot the algae from the aphotic to tne
euphotic zones (76) , the lowering of water temperature ot
the epilimnion, and the modificaiton of the nutrient
availability. The decrease in blue-green algae could result
in a reduction in raw water taste and odor problems. Tnere
also appears to be a reduction in actinomycete population
which could improve water taste (80).
U. Artificial destratification increases the neat
budget of a lake by inducing complete circulation (75) . An
increased rate of productivity results. This is of
particular importance in oligotrcphic bodies of water.
5. Artificial destratification reduces evaporation
rates by slightly reducing surface temperatures during the
summer (81). In areas such as the southwest United States
where water is in short supply and is expensive, significant
savings can be achieved by reducing the rate of evaporation.
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6. Artificial dcstratitication often results in
increased water clarity (75). This appears to be associated
with reduced alqal populations,
7. Winter fish kills may te prevented by artificial
destratification due to the maintenance of high oxygen
levels under ice (82).
Disadvantages
Problem areas associated with these two methods may
include the following phenomena:
1. The increased heat budget produced by artificial
destratification may be deleterious to cold water fishes,
particularly in shallow lakes in which the temperature is
increased excessively at all depths (81). Also, warmer lake
waters may reduce a lake's usefulness as a source or cooling
water for industry and, if the lake is a public water
supply, the attractiveness of drinking water derived from
the destratified lake (77).
2. Both artificial destratification and hypolimnetic
aeration may increase water turbidity due to the
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resuspension of bottom sediments (80). This is often *
temporary problem, however, and may be resolved i / continued
mixing or a change in the location of aerators.
3. In most investigations these methods have ^roauced
a reduction in blue-green algae populations with a
subsequent increase in green algae such that total
productivity remains about the same (7f, ft 3) . In otaer
instances there has been no observable effect on i>lue-green
algae populations with the result that problems associated
with these organisms have remained (8U) .
4. If oxygeriation is insufficient to increase ti.e
hypolimnetic oxygen concentration rarialy enough during
destratif ication, fish kills may occur (85).
5. The artificial destratif icaticn procedure
induce foaming, an aesthetically undesirable \. hencrrenon
(76).
6. The oxyaen demand of resuspended anaerobic mud may
result in a decrease in oxygen concentrations to tne extent
that fish kills occur (77). Ihis is particularly true of
small, very eufcrophic lakes.
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Costs
The costs of applying artiticial destratification
techniques depend on such considerations as systems design,
length of operation, power cost, degree of stratification
and oxygen deficit in the lake to fce destratiried. Tne
findings of a survey of water-utility managers who nave
applied these techniques in an effort to improve or maintain
the water quality of impounded water supplies reveal tnat
although costs vary, certain generalities may be maae (66).
Tt was found, for example, that both the initial cost per
unit volume and the operating cost per unit volume declined
as the volume of the reservoir increased. No clear trend
emerged with regard to the costs associated with the type of
equipment (homemade or commercial) and the operating
schedule used (continuous, continuous all summer, or
intermittant). Tt should be noted that 89 percent or the
,respondents utilized aeration devices and only <* percent
used mechanical pumps. Other less widely used techniques
were employed by the remaining 7 percent The majority ot the
operators (83%) used electrical power. One third of the
respondents employed continuous operation, one third
continuous during the summer and one third intermittant
operation. The concensus costs of all the survey
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respondents arc nresented in Tables 5 and 6. These data
conline all types of eouipr.ent and. operation.
Table 5
Initial Costs Per Unit ^nlure
(Purchase and Installation)
I laxirur 'lean I'in irun
f>16.00/1000 r3 $3.54/1000 r3 $0.°4/1000 r3
($60.50/nil gal) ($13.40/ril qal) ($0.15/nil gal)
l.GC/n3 $0.003/m3 $0.0054/n3
($0.051/1000 gal) ($.013/1000 aal)
$159.70/ha-r $35.59/ha-r $0.41/!ia-p
($19.70/acre-ft) ($4.39/acre-ft) ($0.05/acre-ft)
Operatinn Co.^ts Per Unit T7olur:.e anc riirr
and :iainter.arcr)
! lax irun ."car
S3.T.7/1000 r.3/yr SO.77/1000 n3/yr
($13.90/ril aal/yr) ($2.90/ril nal/yr) (.^0.01/nil qal/yr)
$0.37/n3/yr
($0.014/1000 qal/yr) ($0.003/1000 qal/yr)
$37.4G/ha-r,/"r $7.C2/ha-r/yr $0.02/ha-r/yr
($4.C2/acre-ft/yr) ($0.94/acre-ft/yr) ($0.003/acre-ft/yr)
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96
These costs represent the actual costs incurred in-
applications of aeration devices. It should be noted,
however, that cost estimates for future applications must be
generated on a case-by-case basis. It will be difficult to
determine precise cost estimates, however, as there remains
a lack of information on the exact amount of mixing needed
to improve water quality in a qiven circumstance ana on now
mixing can be maximized with a given power input, thereby
minimizing cost so the the highest benefit/cost ratio can be
obtained (86).
Case Studies
1. El Capitan Reservoir, California, USA (78, 81, 87)
The El Capitan Reservoir is an impoundment on the San
Diego River. This body of water typically experiences one
annual period of thermal stratification usually lasting from
March or April to November or December. The reservoir was
continuously aerated by diffuse air injection during tne
summers of 1966 and 1967. The chemistry and biology ot tne
lake were investigated during these periods as weii as
during the summers of 19 6U and 1967 when normal
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97
stratification was allowed to occur. During the course of
the study the depth of the lake rose from 24.8 m in 1964 to
33.3 m in 1967 and the total volume increased from 1,136 na-
m (9,200 acre-ft) in 1964 to 2,698 ha-m (21,845 acre-ft) in
1967.
The total cost of equipment, materials and labor to
install the system was approximately $6,010. At 6 percent
interest, the 10-year amortization cost will be $82!>
annually. With continuous operation on a 6-month basis eacn
year, total power consumption was approximately $1,674.
Monthly electrical service charges totaled an additional
$177. Including the amortization and power costs, plus an
estimated $250 per year for maintenance and repair, tne
estimated annual cost of operating the destratification
system on El Capitan Reservoir was $2,926.
Changes in the chemistry and biology of the lake were
quite evident following artificial destratification. The
lake became isothermal from top tc bottom. The heat budget
increased. For example, the maximum heat content ot the
lake in 1966 during destratification was 25,116.0 cal/m3
above 0.0°C as compared with the maximum of 22,546.4 cax/m3
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98
above 0.0°C observed during the thermal stratified condition
of 1967.
During destratification dissolved oxygen was distributed
to all depths and was essentially uniform from toy to
bottom. It was observed, however, that the surface oxygen
concentration of about 5 mg/1 found during 1965 was
significantly lower than the 8 mq/1 which occurred in 19t»4
under stratified conditions. This indicates that an
accelerated oxidation rate may have occurred during forced
circulation.
Phosphorus concentrations in the hypolimnion decreased
from as high as 1.4 mg/1 during stratified conditons to 0.1
- 0.2 mg/1 durinq destratif ication. During clestratiti cation
the phosphorus level was uniform from top to bottom.
Prior to destratification the combined concentrations of
iron and manganese were 0.65 and 1.U6 mg/1 at 7 and 17
meters respectively. These values exceed the level of 0.3
mg/1 recommended for potable water by the U.S. Puoiic Healtn
Service. Following destratif: ication, the combined
concentrations of iron and manganese were below 0.3 mg/1 at
all depths.
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99
Benthic organisms such as midge larvae and pupae,
oligochaete worms, nematode worms and freshwater clams; were
absent from the hypolimnion prior to destratification.
During destratification these organisms invaded tne ueepest
part of the lake and increased in total numbers.
Zooplankton populations were also affected by
destratification. For example, over 85 percent or the
zooplankton were found below 10 meters on June 17, 19ob,
under destratified conditions, whereas less than 10 percent.
were observed below this depth the previous year una^r
stratified conditions. Destratification, therefore, allowed
a greater depth distribution of these organisms,
Although no data have been reported on the eftect of
destratification on algal populations in El Capitan
Reservoir, the results presented indicate that artificial
destratification did produce a significant improvement in
water quality in this body of water.
2. Wahnbach Reservoir, Germany (77)
Wahnbach Reservoir is used as a water supply ana as a
source of industrial cooling water. It contains 4,168 ha-m
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100
(33,7UO acre-ft), has a maximum depth of U2.9 m and an
average depth of 19.2 m. The lake is rapidly becoming more
eutrophic due to the introduction of domestic sewage ana
agricultural runoff. During periods of thermal
stratification, a complete lack of dissolved oxygen exists
in the hypolimnion.
The reservoir was aerated by diffused air injection
during the summer of 196U. Oxygen was maintained tnrouyhout
t-.he lake. Unlike previous years, the oxygen content dia riot
decrease to below 30 percent saturation at the mud-water
interface at any time during 196U. Compared to previous
years without aeration when manganese concentrations of uy
to 20 mg/1 were observed, aeration generally reducaa tne
concentration of manganese throughout the lake to less than
1.0 mg/1. Some increase in dissolved phosphorus levels in
the surface water was evident during aeration although this
had occurred previously when there was no aeration. No
increase in production occurred during the destratified
period. A decrease in the population of the blue-green
algae Qscillatoria sp. was observed, however.
Although improvements in many aspects of the water
quality of Wahnbach Reservoir were produced by artificial
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destratification, a detrimental effect occurred. Increases
in water temperatures rendered the water unsuitable for
drinkinq and for industrial coolinq water purposes. To
A
overcome this disadvantaqe, a system of hypolimnetic
aeration was employed to raise oxyqen levels without
increasinq water temperature.
Hypolimnetic aeration of the reservoir was employed from
July to November, 19*6. Thermal stratification was
maintained and the lake became aerobic throuqhout.
Manqanese concentrations tell to below 0.1 mq/1. Pnospnorus
concentrations declined from 80 uq/1 prior to aeration to 20
ug/1 after aeration. Hypolimnetic aeration, therefore,
produced water quality chanqes similar to artificial
destratification without adversely affectinq the temperature
reqime of the lake.
The installation cost for the diffused air injection
apparatus was $3,750. This includes $2,500 for tne purcaase
of a 36.5-kw compressor and $1,250 for the air distrioution
pipe. The operational costs, primarily electrical power
costs, for approximately 5 months of continual aeration were
$2,250 in 196U. The annual operatinq cost was $0.15/1000 nr
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{$.57/mil gal) of drinking water withdrawn from tne
reservoir - 1U.8 million m3/yr (3,900/mil gal/yr).
The hypolimnetic aeration equipment required a Higher
capital investment - $8,250. In addition, $U,500 was
required for a raft with an overhead crane used for
assembling the apparatus. The compressors and plastic pipe
cost $3,750. Total installation cost, therefore, e4ualea
$16,500. The operational costs for hypolimnetic deration
were only slightly less than for artificial
destratification.
3. Hemlock Lake, Cheboygan County, Michigan, USA (76)
Hemlock Lake is a 1.8 hectare irarl lake having a maximum
depth of 18.6 meters. Hypolimnetic aeration was applied to
the lake continuously frcir June 1U to September 7, 1970.
Aeration increased hypolimnetic oxygen levels trom zero
to over 11 mg/1. The temperature of the hypolimnetic water
increased more than 12 C above its normal level. Tnis was
due in part to heat conduction through the aeration tower
and can be minimized by using insulation.
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After an initial increase in phytoplankton cell numbers
immediately after initiating aeration (attributed to tne
leakage of nutrient rich hypolimnetic water through tne
tower into the epilimnion), the standing crop decreased from
over 30,000 cells/ml to less than 500 cells/ml.
Concomitantly, Secchi disk measurements increased to over 9
meters, the deepest ever recorded for Hemlock Lake.
Aeration did not appear to affect the periphyton standing
crop. Following aeration, zooplankton inhabited the lower
lake waters and their numbers increased until preaation
stress by fish caused zooplankton numbers to decline. Tue
total number of zoobenthos was increased by aeration
although the biomass remained the same. The zoobentnos were
able to inhabit the deep water during aeration as were
rainbow trout.
The results of this study indicate that hypolimnetic
aeration may be an effective method of alleviating the
eutrophic condition of a body of water.
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4. Boltz and Falmouth Lakes, Kentucky, USA (79, «d, 89)
Boltz Lake and Falmouth Lake were artificially
destratified by diffused air injection during the summer of
1966. Bullock Pen Lake, also in Kentucky, was not
destratified and acted as a control. The morphological
characteristics of the lakes are given in Table 7.
Table 7
Morphological Characteristics of Bullock Pen,
Boltz and Falmouth Lakes
Bullock
Pen
Boltz
Falmouth
Volume
3.95x10'
3.58x10'
5.69x10'
Maximum
Depth
m
14.6
Average
Depth
m
7.0
Surface
Area
hectares
56.8
18.9
12.8
9.1
6.1
38.4
90.0
Intermittant aeration was used. Boltz Lake was
destratified four times during the period June to September
and Falmouth Lake five times.
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In both lakes, the temperature of the bottom water
increased during the aeration periods and decreased or
leveled off between aeration periods. The net effect of
intermittant aeration was to increase the bottom
temperatures by over 20 C during the course of the summer.
Likewise, hypolimnetic oxygen concentrations increased
during the mixing process and decreased between periods ot
artificial destratification. The net effect througn the
summer was to increase the oxygen levels of the deeper water
and decrease the concentrations of reduced materials such as
iron and manganese.
The sum of the ammonia and nitrate nitrogen
concentrations at the 1.5 m depth in the unmixed laxe
remained at about 0.2 - 0.3 mg/1 throughout 1966. boltz
Lake exhibited concentrations in about the same range at the
1.5 m depth except for the last mixing period. Duriny tnis
period the concentration of NH3-N plus NO3-N increased to
between 1.0 and 1.5 mg/1 after which it leveled ott ana
subsequently declined to torirer levels. Smaller increases
in the concentration of ammonia and nitrate nitrogen
occurred during two of the mixinq periods in Falmouth Lake.
In each case, the concentration declined after aeration
stopped.
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106
The soluble phosphorus concentration at the 1.5 m depth
in the unmixed lake varied between 20 and 50 ug/1 in 1966.
Concentrations at the 1.5 m depth in Boltz Lake, however,
exhibited an increase from 5-10 ug/1 in May to
approximately 100 ug/1 in September. Falmouth Lake
exhibited a net decrease in phosphorus concentration at the
1.5 m level from May to September although the
concentrations increased during most of the mixing periods.
The surface plankton counts in the unmixed lake were
between 1,000 and 3,000 per ml from June to mid-September.
Boltz Lake exhibited declines in plankton counts during
three of the four mixing periods and Falmouth Lake during
two of the five. When these declines took place they
occurred at all depths. In most cases, an increase in
plankton counts took place after mixing stopped. These
increases were not of "bloom" proportions, however, and
despite periodic increases in nitrogen and phosphorus caused
by mixing, excessive algal growth never occurred during any
of the artificial destratification experiments, wnereas the
unmixed lake exhibited the predominance of blue-green algae
characteristic of the geographical area, a shift to green
algae occurred during several of the mixing periods in both
test lakes.
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It r-ay be concluded fror this :;tudy that artificial
dcstratification elirinatcs them a 1 stratification, adds
dissolved oxyrren to th<; vatcr, causr- oMidrti^r. o^ reduced
substances arc"1 can produce- a shift in nlral ^r^dor inar.cr
fron blue—rreen to green species. The results also inc'icato
that artificial destratification should be initiated in the
spring or early sunrier and should be contiruod, at least
periodically, throughout tho sunrrr for l.o^t .117 rovn ort of
v/atf-r c;uality.
5. Parvin Lake, Colorado, VE? (PO)
Parvin Lal;e van artificially dostrati fier' fror Hover] rr,
19GP, to iJecer) rr, 1P7P, in an e^^ort to irv.-rovr t:ie
\ inter hyj olirnrtic oxyg^r. deficit and surfer Muo-c
algae 1 looms. Continuous air diffusion was erployed.
Parvin LaJic has a surface area of 19 ].a, r-axirtun depth of 10
r. and a rcan dej'th of 4.4 r. It is located at an rlevatior
of 2,500 n in the RocV.y .Mountains of Colorado.
Total phytoplanhton abundance decreased ir Parvin Lav«
during artificial destratification, but th.p decrease x;as not
uniforn among all phyla, freen algae declined during
destratification. This may have been due to the coldor than
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108
normal winter water temperatures and warmer than normal
summer temperatures. Planktonic diatoms decreased in
population size durinq the winter when they normally
dominate. Several tlue-qreen algal species increased in
number durinq the summer over previous, untreated years,
namely Anabaena f_los-aguae, Aphanizomenon flos-aquae and
nomphosphaeria lacustris.
These results indicate that complete understanding of
the response of eutrophic lakes tc artificial
destratification is lackinq. whereas other investigators
observed decreases in blue-green alqal populations durinq
mixinq periods, this study tound that several of these
species increased in number. Because of this difference in
observed response, it is evident that the potential eftects
of artificial destratification should be evaluated on a
case-by-case basis.
Drawdown
Water level manipulation exists as a potential mechanism
for enhancing the quality ot certain lakes and reservoirs.
Lake drawdown has been investigated as a control measure for
submersed rooted aquatic vegetation, as a means to retard
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109
nutrient release from the sediment nutrient pool, and as a
mechanism for lake deepening through sediment consolidation.
Observations from natural drawdown and subsequent
exposure ot the bottom sediments have indicated irar*ed
improvement in the water quality of two Florida lakes.
Before drawdown the lakes produced heavy algal crops. Alter
drawdown and sediment drying, rooted aquatic plants replaced
the algal community making the lakes more amenable to yame
fish.
Experiments, with sediments froir Lake Apopka, Floriaa, in
1967-68 showed that when the sediirents were dried and
reflooded a balance of aquatic weed and shoreline (emergent)
vegetation grew (91). Further, the sediments oxidized ana
would not resuspend upon flooding. It was concluded trom
these studies that drawdown for 6 to 8 weeks during the dry
season should result in a suitable aquatic weed crop.
Drawdown has been carried out in three Wisconsin lakes:
Marion Millpond, Snake Lake (70) and Jyme Lake (92). At
Marion Millpond many manipulations besides sediment exposure
were made: bottom stumps and logs were removed; some
sediment was removed and sand and plastic were placed i
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110
some of the littoral areas. Therefore, the effects of
sediment drying were masked by these other rehabilitation
techniques.
At Snake Lake the primary objective was to restore tne
lake by pumping nutrient-rich water trom the lake and
allowing it to be replaced with nutrient-poor qroundwater.
Tn lowering the water level by 3.35 meters the seuiments
were exposed to air which resulted in extensive compaction
and likely chemical alterations by oxidation. The
phosphorus concentration decreased by half after tne lake
refilled but this likely was mainly attributable to tne
dilution water.
Jyme Lake is a 0.45 hectare, 3,7 m deep acid-boj s
lake in Oneida County, Wisconsin. Beginning in October
water was pumped interirittantly for a 10-day period to a
nearby low-lying cattail marsh in an effort to drain tne
lake to allow investigation of sediment consolidation as a
lake deepening technique. Attempts to completely drain tne
lake were unsuccessful due to the flow of low-solids mud ana
peat on the lake bottom and from teneath the vegetative mat
of the bog, and a subsequent subsidence of the level oi tne
bog. The wood fragments in the mud clogged the pump
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111
impeller forcing termination of the project prior to winter
freeze-up. The Jyme Lake experience indicates that although
lake drainage and sediment consolidation is a potential
physical deepening technique, to be effective the laxe must
be completely drained and the water table must be maintained
below the surface of the lake sediment surface. Because ot
possible pumping problems and slumping difficulties
encountered during the draining of bog lakes, this technique
may be more applicable to lakes with a greater percentage ot
inorganic sedimentary fill.
In the Tennessee Valley Authority lakes it was observed
that lowering the water level 1.83 meters for a period of 21
to 25 days during the winter provided a 90 percent reduction
in the acreage infected with Mvriophvllum s£icatum (93).
Studies on drained marsh areas have shown that water
removed during the drainage period would carry with it much
of its total burden of nutrients (9U). It was concluded
that frequent drainage could heavily deplete the fertility
of marsh environments.
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Harvesting Nuisance Organisns
Algae
Algal harvest is particularly difficult because trie
algae are normally in dilute suspensions and of small
physical size. For these reasons most attempts at algal
harvest have been conducted on lagoon waste water effluents
which have a relatively high concentration of algal cells.
Even at these concentrations Oswald and Golueke (9b)
indicate that in order to obtain a usable, economically
feasible end product, the following three steps are
necessary: 1) initial concentration of the algal
suspension, 2) dewatering and concentrating the resulting
slurry, and 3) drying the dewatered algae for storage and
handling.
Algal harvest may be accomplished by centrifuging,
filtering, coagulation, microstraining, sonic vibration,
flotation, and changing of ionic characteristics ot t.he
algae with ion exchange resins (96). Coagulation of alyae
with aluminum sulfate, lime, and alum have been used in
combination with the above methods (97).
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A high grade end product is most cheaply obtained by
centrifugation, whereas a lower grade product is most
cheaply obtained by combining centrifugation with tne
coagulation or flocculation process (96). According to 1967
estimates one metric ton of dry algae (low grade) could be
produced at a cost of $66 to $88 ($60 to $80/ton). No firm
market value for the finished product could be establisned
in 1968, but it was estimated to be worth about $95 per
metric ton ($86/ton) with an additional $10.00 per 378b m3
(mil. gal.) of high guality process water as a frinye
benefit. Products of the process would then yield axi income
of nearly $105 per metric ton of dry algae at a production
cost of $66 to $88 for a net protit of $17 to $39 per metric
ton of dry algae. According to Levin and Barnes (^8) a
similar quality low grade product iray be produced by tne
froth flotation process for approximately $52 per metric ton
($U7 per ton). Assuming the same market value for the end
product this method might realize a net profit of nearly j>55
per metric ton ($50 per ton). If these figures represent
real numbers a municipality or industry might be able to
economize significantly on wastewater treatment by narvest
of algae.
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114
Algal harvesting studies which utilized the eftluent
from wastewater lagoons have demonstrated that nearly 90
percent of the nitrogen can be removed in the form of algal
protein (99, 100). One field study demonstrated 50 to 70
percent inorganic nitrogen removal and 19 to 68 percent
phosphorus removal from wastewater with algal harvest (101).
Soluble phosphate has been reduced by 90 percent using nigh
rate algal culture techniques (102).
Under highly favorable climatic conditions up to 70
percent of the nitrogen and 50 percent of the phosphates
have been removed from wastewater by algal action alone
(103). In laboratory cultures under controlled conditions
50 percent of the total inorganic nitrogen was removed by
algae in one day and 95 percent in four days (104).
It has been estimated (95) that .6 million hectares (1.5
million acres) of land devoted to algal culture would
satisfy the oxygen demand of all liguid-borne wastes in
1967. The need by the year 1990 is projected to be aDOut
2.42 million hectares (6 million acres). The algae
recovered would meet approximately one-quarter of the
protein needs of the nation's livestock industry, and since
the 0. S. has about 121.4 million hectares (300 million
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115
acres) devoted to protein production, the savings in water
resources normally used to produce protein could amount to
11 3
2.5 x 10 m° (200 million acre-feet) each year (96). This
technique should be evaluated with regard to efficient land
use practices.
Data regarding algal harvest from lakes are severely
lacking, probably owing to the relatively sparse algal
oopulations found in lakes. Levin and Barnes (98) noted
that the efficiency of harvest was inversely proportional to
culture density. Another probable reason for lack of lake
data is that algal bloom populations usually consist or
blue-green algae for which there is a limited marKet. Green
algae usually associated with the nutrient-rich wastewater
lagoons, on the other hand, are a potentially valuable
source of protein.
Despite the apparent success of some methods ot algal
harvest as a measure of nutrient removal, many problem areas
still remain. It appears now that there is little nope ot
developing an in .situ lake-oriented method of harvesting
algae that would be economically feasible.
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116
Macrophytes and Higher Organisms
Excessive macrophyte growths due to nutrient im£>
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117
designed to physically uproot and destroy these plants
(107), but both types of plants have economic value it
controlled; pondweed as the major duck food plant in tae U.
S. (11U), and milfoil as a feed supplement (115, 1 1fa).
Development of specialized cutting machines has
progressed to the point where relatively efficient cutting
can be accomplished, but the major expense comes in
collecting the cut debris and removing it from the water,
Various devices for reduction of weight and volume ot tne
crop have been designed, such as screw presses (117, 11b,
110), high pressure crusher-rollers (111, 117), brusn
chippers and crushers (106), as well as assorted efficiency
improving pretreatments (108, 117, 110, 111).
From a health related standpoint, especially with
reference to food production, Abou-El-Fadl et al (119)
observed no infectious stages ot helminths (schistosomes) in
harvested water hyacinth (this is a severe problem in
temperate, tropical, and subtropical countries), but noted
that the crop must be composted before use as an organic
manure.
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Various estimates ot nutrient removal efficiency nave
been made, but there is widespread disagreement. Lee
is of the opinion t.hat harvesting, in general, does not ma*e
significant inroads in the nutrient balance of the lake,
although it does remove certain aincurits ot nitrogen ana
phosphorus. Rogers (121), however, points out that 1
hectare of water hyacinth could absorb in 6 months tne
annual nitrogen and phosphorus wastes of about 550 people.
Livermore and Wunderlich (106), cite work (106, V2.2) that
indicates that the harvest of six species of plants in La*e
Mendota, and milfoil harvest in Caddo Lake, could yield up
to 202 kg/hectare/year (180 Ib/acre/yr) of nitrogen and 31.8
kg/hectare/year (28 Ib/acre/yr) of phosphorus, which would
represent substantial nutrient removal in many lakes. Youat
and Grossman (107) indicate that primary production is
reduced by harvesting, but only if the intact plants are
removed from the area but, "if tco much vegetation is
removed, the availability of these pollutants to otfter
organisms (such as algae) is increased....the problem is
resolved by managing a population on a sustained yield
basis." See also (123).
Steward (124) indicates that.emergent macrophytes are
substantially more productive (in terms of dry weight) than
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119
submerged rooted species, and cites the work ot tne
County Pollution Control Department, Orlando, Florida, wnere
the nutrient balance of a small eutrophic lake has been
successfully restored by qrowing water hyacinths in a fenced
area in the center of the lake. Atter one year the lax.e was
clear and supporting fish.
In studies ot two full scale treatment plants usea iu
processing citrus pulp waste (113), the perforrrar.ee ot water
hyacinth in the removal of nutrients in aerated lagoons ana
oxidation ponds has been evaluated. It was determineu tnat
a minimum of 5 days retention time was requirec to attain
substantial nutrient removal, and the hyacinths were moat:
efficient at D.O. concentrations below 0.5 mg/1, ana rurtrier
that the microbiota attached to the roots of the nyaciatii
were responsible for substantial reduction of EOD (70
percent) and COD (U7 percent) . A considerable amount of
nutrients (contained in the presswater) were releasea during
squeezing in a drying process, i.e., . U hectare (1 acre) ot
hyacinths at 336 metric ton/hectare (150 ton/acre), would
yield 128.7 m^ (3U,000 gal) of pressed liquor containing oJ
mg/1 PO4~P and 335 mg/1 total N). Analysis showcu an animal
feed value of the processed hyacinth comparable to aitulta
hay.
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120
Steward (12U) further calculates that water hyacintn has
the highest nutrient reduction potential of eight species
compared. Taylor, Bates, and Robbins (125) assayed the
protein content of water hyacinth finding that, "altnough
the quantity of the protein extracted was low, it appeared
to be of good nutritional quality as evidenced by tne
proportions of essential aniino acids," The crude protein
concentrate (33.6% recovery by alkali) ranged from a summer
low of 4.7 percent (dry weight) tc 5.8 percent in winter,to
9.2 percent in the spring.
There has been considerable work done in Germany over
the past 10 years with the bulrush, Scirpus lacustris L., as
a biological filter for use in pond reclamation and sewage
treatment (126 - 128). This rush, which has worldwide
natural distribution, can grow in an astonishing variety ot
situations, including saline water and highly contaminated
freshwater. Scirjous has been shown to have the aoility to
penetrate and break chemically precipitated hardpans in
holding ponds, allowing percolation to the ground water.
Before the introduction of the rush, the water stagnated.
Scirpus, by virtue of a root exudate termed a "phytondice",
is able to lyse (kill) ccmmon sewage bacteria (F;. coti,
Salmonellae, etc.) completely, rectify the pH of tne
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entering sewage effluent to 7 t 0.5, and is capable of
removing large amounts ot organic and inorganic nutrients,
storing these nutrients in its "phyllosphrre" or leaf biaae
which is harvested periodically and utilized in a number of
ways, e.g. fuel, cattle feed roughaae, paperboard tioer. in
pilot, plant operations, flow-through channels of dcirpus
have shown the ability to reduce PCC by 96 percent, orten to
less than 5 mg/1, phosphate by 50+ percent, and ajuuonia by
more than 99 percent (22 mg/1 to 0.1 mg/1). The process
improves the activated sludge process, is capable ot dU
percent reduction of total nitrogen, and its metabolism is
reduced by only UO percent under ice cover. The aesigns are
suitable for small cities in the 20,000 to 40,000 population
range. There are an increasing number of installations in
European countries, treating both domestic and industrial
effluents. Steward (12U) reports that an industrial
installation in Germany treats 5 Trillion cubic meters or
effluent per day by passage through 20 basins, 400 meters
long by 50 meters wide, planted with Scirpus.
The other area of possible interest in nutrient removal
is that ot vegetation consumers, such as fish and shellfish.
Some research seems promising. Greer and Ziebell (12^)
tested various fish and shellfish, and found the oriental
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clam, Corbicula fluminea was most effective; at
concentrations ot 5.0, 10.0, and 15.0 mq/1 PO^ this system
can remove the PO- ion to below 0.30 mg/1 in 16 days or
less, yielding a clear effluent. This process occurs partly
by sedimentation of psuedo-feces (mucous bound undigested
pellets of algae) which are not resuspended. X-ray
diffraction of sediments showed that PC^ had been
precipitated in the form of hydroxyl-apatite. They
concluded from studies with Tiiafia arid channel catrisn,
that where algal blooms could be controlled, removal of
nutrients via sport fishery could Le feasible (algal blooms
generally result in massive fish kills).
Corey et al (129) estimated that fish harvest, on a
sustained yield basis, would result in catches of 3,37 kg per
hectare (300 Ib/acre) of water surface annually (spore
fishing about 1/3 of the total), which would represent
removal of about 7.8 kq of nitrogen and 0.67 kg of
phosphorus per hectare (7 Ib N/acre and 0.6 Ib P/acre).
There has been recent work in this country concerning
the use of Ctenopharygodon idella Val,, the white amur or
grass carp, in controlling aquatic plants. Claims have been
made that experiments in Arkansas have proven the wnite amur
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to be one of the best control agents for aquatic vegetation
(130).
The state of Arkansas has released the white amur into a
number of waterways including some which will provide the
fish access to the Mississippi River Basin tributaries. The
neighboring states of Texas and Missouri, however, have
banned the importation of the grass carp.
Results from studies in Europe and Asia on the use of
this fish for weed control purposes are less encouraging
than those from the Arkansas studies. Opuszynski (131)
reported that grass carp fry eat only animal food such as
zooplankton and Chironomidae larvae until they reacn a
weight of 1.8 g and a length of 36-U3 mm, and that the use
of macrophytes in their diets increases with increases in
size. It was also reported that aniiral protein apparently
is a necessary addition to the diet for normal growth and
development of these fish (131). When given a choice the
grass carp seemed to prefer macrophytes to algae. According
to the Sport Fishing Institute Bulletin (132) a recent
release from the Missouri Department of Conservation
provides preliminary evidence that the white amur prererred
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12U
amphipods over weeds when given a choice, and ate weeds only
in the tank deprived of amphipods.
In summary, it appears that although the technical
methods for nutrient removal via harvesting are becoming
increasingly diverse and sophisticated, none is economically
feasible on self-supporting basis, although the costs appear
to be within reason for some situations. Increased research
indicates that markets will develop for products created,by
these harvesting procedures. There is substantial agreement
among authors that complete eradication of any species of
plant is undesirable, and management, especially by
biological means, is the ultimate goal.
Biological Control of Nuisance Organisms
Algae
Hasler and Jones (133) reported that dense growths ot
aguatic macrophytes were inhibitory to the growth of
phytoplankton, both by direct cbmpetition for nutrients and
by shading. On the other hand, Mulligan (114) reported that
the technique (used primarily by fish culturists) ot massive
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125
fertilization stimulates blooms of green alqae, wnicu
submerqed macrophytes and prevent their ;3evelof merit.
Neither technique really solves anything, txcnanaing one
problem for another.
Porter (13U) reported on the effect ot grazing
Oa£>hnJLa and related zooplankton on natural phyto
populations in a mesotronhic kettle lake exper imentdi in
situ set up. Selective reduction and siqniticant
suppression of numbers of phytoplankton are acconplisneu by
Daphnia.
Mattox, Stewart, and Floyd (135) reported the t-rt^
of virus particles in four genera of Ulotr ichalean
alqae (viruses were previously unknown in eukaryotic al*jae) .
These findings greatly increase the chances of develo^iuj
viral control procedures tor green alqae. Saffermdn ana
Morris (136) reported the first isolation of blue-green
alqal virus, which was found to he highly specific tot
several closely related blue-green alqae, Lyngbya.
Plectonema, and Phormidium, all of which are now classilied
by Drouet as Schizothrix calcicola.
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126
A significant amount of work has been done to develop
the virus as a control measure (137, 138) in order to ta*e
advantage of the observed natural phenomenon of abrupt
massive die-ofts of blue-green algal blooms caused oy
viruses.
Broad-spectrum control of blue-green algae is also
exhibited by a bacterium, Mv_xobacter sp., as reported b>
Shilo (138). Bacteria and fungi apparently hold oome
promise as control agents, but much work, as with viruses,
remains to be done.
Macrophyt.es
Cappelman (139) has developed a culture technique for
detached water hyacinth leaves that has allowed
demonstration of the pathogenicity of Alternaria s^., an
aquatic fungus, to the hyacinth. The system holds
considerable promise for the demonstration of pathogenicity
of other organisms to the hyacinth, including viruses and
insects. Sculthorpe (140) reports African work on the
sedge, Cyperus rotundus, noting that the planting of
Eucalyptus trees nearby reduces the growth of the sedges.
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127
Also, work has been aone in Italy on the control or tne
qrass Echinochloa crus-cjalli by the smut funqus, Sorosporiuin
The water hyacinth weevil, N^ochetina bruchi Hustacne,
showinq promise as a control aqent, has been introduced to
numerous waterways in Florida by the Army Corps or c,n-jineers
(1*11) after extensive research in South America. Couison
(1U2) reportinq on the oriqinal research and future plans
for arthropod control aqerits, believes that signincaat
control of the hyacinth will result v,ith widespread
distribution. One species cf mite, Crt.hoqalumna terebrantis
Wallwork, apparently introduced with the hyacinth, also
shows considerable control activity, work is being
conducted in Uruquay on the crambine moth Acigona intuselia
(Walkor) , whose larvae are stem borers and althougn tney may
feed on sugar cane and rice, are only able to complete tneir
development on water hyacinth (Eichornia) or Pontederi^ (a
closely related genus) .
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The nymph of an acridid grasshopper, rornggs acjuatic_urr,
Bruner, has also shown considerable ability to defoliate
water hyacinth.
The developmental vvork on these arthropods is i;ciavj aorie
at the ARS Laboratory in Albany, California, and woria-wide
under PLU80 funds. Thrips, previously introduced, nave not
successfully controlled the hyacinth.
Durinq the j.eri°^ 1962 to 1967 work was conceatrateu on
the flea beetle, Aaasicles, which is rcost specific tor tae
alligator weed, Alternan.thera
introduction into problem areas has resulte.3 in soiuewnat
successful control (11U, U2, 143).
j
Baloch, Khan, and Gharii (1^4) reported on the isolation
and study of four insects which feed on water milroii
(Myrjoghyl lum spr. ) in Pakistan, and their possible use ao
control agents. Frequent fluctuations in wator levels
prevent the buildup of large enough populations or taese
curculinoids to significantly affect the irilfoil, out it
such fluctuations were prevented, the introduction ot tnese
insects, which damage both seea-l earing capacity ana
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submerged parts of the plant, might result in effective
control.
Attempts have been made (114, 1UO, 145) to
advantage of the accidental introduction of the snail,
Marisa cornuarietis L. , for the biological control ot
aquatic weeds. Although they are voracious consumers ot
aquatic weeds, they tend to disperse rather than uuiia up
dense populations, and have not keen numerous onougri to
significantly affect the standing crop. One approacn
suggested is to confine them to small lakes, rather trian the
canals through which they have spread.
Potamogeton sp. is the primary food plant of numerous
wild fowl, such as ducks, tut these biras apparently do not
have significant impact on aquatic weed populations.
Only one mammal, the manatee, Trichechus manatus
latirost.ris, has been experimentally considered for control
purposes (140, 146), but despite the fact that it consumes
tremendous quantities of aquatic weeds, it is a rare animal,
difficult to locate, catch, and transport, has not bred in
captivity or in freshwater, and simply does not exist in
large enouqji numbers to have a significant impact in terms
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130
ot overall programs. In individual experiments, aithouyn
expensive to conduct, the manatee has proven to be a very
efficient weed control agent.
Chemical Control of Nuisance Organises
Algae
Fitzgerald (1U7) has compiled an excellent review of
alqiciues, especially as they apply to lake management.
Although the most desired method of alleviating
eutrophication is to restrict, nutrient input, many
situations have deteriorated to the pcint where direct
measures must he taken to control algal growth, ana one or
these is the use of algicidal chemicals.
Copper sulfate is procably the most widely usea cnemical
against taste and odor causing algae, floating hlue-«jreen
algae and filter clogging dlgae. Over 11,000 metric tons ot
copper sulfate are used for this purpose per year (1**7) at
concentrations ranging from less than 0.5 mg/1 to more tnari
10 mg/1, according to the density ot algae and relative
water quality. Application methods vary from spraying from
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131
a boat, or dragging a sack cf crystals behind a skitt, to
aerial systems including helicopters.
Test tube experiments with potassium permanganate have
shown it to be more toxic to certain algal species tnari
copper sulfate (148), Because potassium permanganate not
only kills algae, but also eliminates tastes and odors ana
removes iron and manganese sulfates, it may find usage in
the treatment of raw water reservoirs (1U8). Altnougn
organic mercurial algicides are potent and very ertective,
they are more hazardous in the long term to higher orjanisms
in the food chain, including man, and must be used with
extreme care. Other algicides of some use are the resin
amines, triazine derivatives (such as simazine) , a mixture
of copper sulfate and silver nitrate, and ammonium
compounds. Since the resin amines and copper are toxic to
fish, they must be used with caution. Simazine, whicn has a
relatively low mammalian toxicity (11**), controls plaaKtonic
and filamentous algae through inhibition of the Hill
reaction. Although it does not appear toxic to zooplaukton
and fish at recommended levels, it is taken up and
concentrated in fish tissues. Mulligan (114) reports tnat a
30:5 weight ratio of copper sulfate and silver nitrate nas
been effective.in Czechoslovakia.
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Macrophytes
Timmons (149) and Mulligan (11U) have reviewed the means
of chemical control thoroughly. The following herbicides
are the most widely utilized presently: 2, U-D and other
phenoxy compounds, dalapon (2, 2 dichlcroproprionic acia),
diquat (6, 7-dihydrodipyrido (1, 2-a:2;1»-c) pyrozinedium
salts), paraquat (1, 1'-dimethyl-U, U1- bipyridinium salts),
acrolein, xylene, dichlobenil (2, 6-dichlorobenzonitriie),
and diuron (3-(3,U-dichlorophenyl)-1, 1-dimethylurea) .
Diquat, paraquat, and dalapon are the most widely used
throughout Europe; but diuron is used almost exclusively tor
control of aquatic and bank weeds in the Netherlands,
3-amino-s-triazole (amitrole) and 3-amino-s-triazole +
ammonium thiocyanate (amitrole-T) are the most widely used
herbicides for aquatic and bank weeds in Australia. Tnese
latter compounds are restricted or banned in the U. 6.
(149). Diquat, paraquat and dalapon are safe for tish;
dalapon and diuron are safe for hurrans and livestock.
Mulligan (114) indicates that esters of 2, U-D are much
more effective in killing aquatic plants than amides of
2, U-D, although there is much controversy over 2, 4-D
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residues accumulating in food organisms such as snellfisn.
2, U-D is reported to be photo-oxidizable and can oe broken
down by soil microorganisms in U-6 weeks to humic acids.
The butoxyethanol ester of 2, 4-D was used to control
Myriophyllum in the TVA Lakes in 1967 and Trapa natans
(water chestnut) in the Hudson and Mohawk Rivers.
Application of 2, 4-D usually results in temporary increases
in heterotrophic populations in the waters (114).
Silvex is a non-selective, slow acting herbicide whicri
remains in the water up to 5 weeks. Different formulations
have differing toxicities to food chain organisms, tne least
toxic of which is the potassium salt (114)
Fenac (2, 3, 6-trichlcrophenylacetic acid) is a
persistent non-selective agent, reportedly of low rood cnain
toxicity (114).
Endothal (3, 6 Endoxohexahydrcpthalic acid) is used to
control submergent plants, sometimes in combination with
si1vex. There is substantial concern over its unknown mode
of action and unpredictable toxicity to fish and other food
chain organisms.
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13U
Diquat-bromide (1, 1-ethylene-2, 3-dipyridylium
dibromide) kills submerged plants on contact, has relatively
low toxicity, and can he removed from the water by
adsorption onto clay particles and subsequent sedimentation.
In summary, the following observations should DC maae:
inadequate information exists concerning alqicicie ana
herbicide residues, breakdown rates, and long-term ettects
on other orqanisms; when plants are killed chemically,
oxygen levels quickly decline, often to levels toxic to
other organisms; plant-bound nutrients are released into trie
water; chemical agents offer only temporary, symptom
suppressing relief; treatments must be repeated frequently,
often semiannually or irore; chemical kills of macropnytes
are frequently followed by massive algal blooms; ana some
herbicides, such as endothal and silvex, may damage cro^s if
the water is subsequently used for irrigation.
CONTROL AND REMOVAL OF HAZARDOUS MATERIALS
Contamination of lakes with various hazardous suDstances
is an everpresent threat. Industrial accidents, spills
occurring during transport, intentional dumping or plain
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135
carelessness may result in the release of a variety ot toxic
or noxious substances to the environment, with subsequent
transport to lakes and reservoirs.
The initial effort in combating the problems ot lake
contamination with hazardous substances must be the
establishment of sound preventive measures througn the
cooperative efforts of the public, industry and government.
Prevention, in order to be effective, must be a requirement
of law, with appropriate controls and guidance imposed by
the various levels of government. Secondly, industry must
meet its moral and legal coirmitments to society ana trie
environment by implementing appropriate precautionary
measures including proper inhouse plant design, adequate
safeguard mechanisms and procedures, and conscientious
management policies and operational practices.
Precautionary Measures
Even with the best preventive methods in effect,
accidental and deliberate contamination of lakes witn
hazardous substances will occur. A line of defense geared
tor an immediate response to spilled substances is essential
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136
it major catastrophies are to be averted. The essential
components of the response mechanism include capabilities
for tho containment or confinement of the spilled suustances
and removal or inplace treatment (inactivation) while the
material is concentrated in a localized area.
Containment of spilled materials will not always be
possible, even though an efficient spill response system is
in operation. A percentage of the spills will not be
detected or reported until after the spilled material nas
dispersed throughout the lake. Also, continuous or
intermittent discharges of toxic cr other hazardous
materials over a period of time may cause lake-wide
contamination which precludes the use of containment
devices.
Decontamination
In lakes where widespread contamination has occurred and
ecological damage has resulted, restoration programs wili
have to be initiated once the source of contamination nas
been curtailed. If ecological damage has been severe and
the contaminating material is present in the lake in
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137
sufficient quantities to impede the natural recolonizatioa
of disturbed ecosystems or to hinder artificial j: ro^a^acion
efforts, a proceavjre tor treating or removing the
contaminant must be implemented.
Few in s^tu techniques for remcvinq or treating
hazardous materials in lakes have proved effective. Jiace
many toxic substances such as heavy metals and pesticides
are readily sorbei onto particulate matter, incorporation oi
the material into the sediments and biota occurs very
rap>idly. Consequently, such schemes as flushing, diiLitiou
and filtering of lake water do not necessarily remove tno
contaminant from the system, as the materials aro
available for recyclinq from the sediment an 1 Lioi
reservoirs.
Lambou (150) summarized existinq experiences ana
approaches which have been considered for deal inn wicri
mercury contamination in aquatic systems. Since mercury is
one of the most hazardous of the heavy metals in tiie
environment, due to its tendency to be bioloqically
methylated, procedures which are effective in restoring
mercury contaminated lakes may possibly be applied to iaK.es
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contaminated by other toxic substances. The following is
taken from Lambou [150] :
"The continuing supply of mercury from
bottom sediments to the water and the slow
rates of excretion of mercury fcy fish give
little hope for quick improvement in levels of
mercury residue in fish. The Swedish
experience confirms this. In Sweden mercury
in pike in most lakes has dropped little if at
all since mercury bans became effective in
early 1966. These lakes where the fish
residues have not dropped tend to be
biologically poor and acid. Only about three
lakes apparently have had mercury levels in
pike drop to a demonstrable extent. Rivers
have a better chance due to continual flushing
action.
"Jernelov (1969) [151] calculated that it
would take from 10 to 100 years for the
methylation process to remove the mercury from
the bottom of lakes. These calculations were
based on the yield over a period lasting from
1 week to 2 months of mono and dimethylmercury
from bottom sediments taken from contaminated
lakes and rivers and kept under natural
conditions. In Minamata Bay, Japan, once the
cause of the pollution was determined and
eliminated, mercury levels in shellfish
dropped from 35 ppm to 10 ppm over a two year
period and remained constant for at least a
five year period (Trukayama, 1966) [152] .
Rivers should have a better chance of being
decontaminated because of the flushing action
of currents moving sediments downstream.
Mercury levels of salmon placed in cages below
former sources of mercury in some Swedish
rivers showed considerable improvement within
3 years (Study Group on Mercury Hazards, 1970)
[153].
"Swedish workers have considered the
following approaches to the decontamination of
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139
mercury contaminated waterways: (1) introduce
oxygen-consuming materials to create
continuous anaerobic conditions in the
sediments, thereby reducing methylation, (2)
increase the pn of the sediments to favor
dimethylation and increased volatilization,
(3) cover the sediments with fresh finely
divided materials with hiqh adsorptive
affinity (e.g., quartz and silicates), (U)
cover the sediments with inorganic inert
materials ot any type, i.e., bury them, and
(5) removo mercury-bearing sediments by
dredging or pumping (Study Group on Mercury
Hazards, 1970) [153]. The first two
approaches appear to be in practical, however
Sweden is evaluating the other approaches
(Study Group on Mercury Hazards, 1970) [153],
"Experiments have been conducted in
Sweien to evaluate covering sediments by
layers ot inorganic sediment of varying
thicknesses (0-20 en), with and without
T.U.tJjLicijae (olioochaote worms) and Anodonta
(a bivalve)(Study Group on Mercury Hazards,
1970) [153]. These studies have revealed that:
(1) in the absence of Tubi f icjldae,
methylmercury accumulated in fish only when
the sediments were uncovered, (2) in the
presence of large populations of these worms,
fish accumulated methylmercury when the
covering layer was less than 2 cm, and (3) in
the presence of An2il2Bi^» which stirs the
sediments, leakage of methylmercury occurred
it the covering layer was less than 9 cm.
"Swedish workers have conducted tests to
evaluate the ettectiveness ot ground silicate,
on the uptake of mercury by fish from
sediments contaminated with metallic mercury,
ionic mercury, and phenylmercury (Study Group
on Mercury Hazards, 1970) [153]. These tests
have, revealed that there was no reduction in
uptake when the pollutant was phenylmercury;
however, a decrease in uptake by a factor of
two occurred when inorganic mercury was the
pollutant.
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140
"The removal of mercury contaminated
sediments by dredging appears to have some
serious shortcomings. For one thing, the cost
to dredge any extensive area may be excessive.
The dredging of a Finnish port increased the
soluble mercury concentration in the water
from a level of 0.5 to approximately 10 ug/1
(Stephan, 1971) [15U] . This increase took
•some weeks1 to reach a peak; however, it
returned to backoround in a •few more weeks'
(Stephan, 1971) L15u] . Swedish workers were
of the opinion that by dredging there was a
considerable risk of increasing the rate ot
methylation of mercury in the sediments
(Stephan, 1971) [15U]. Measurements taken on
sludges dredged from mercury sludge banks in
Sweden indicated that while some 95 percent of
the suspended solids can fce retained in the
sludge, only 50-60 percent of the mercury will
remain in the sludge, the remaining UO-U5
percent being discharged with the supernatant
(Stephan, 1971 [154],"
Additional information on the effects of sand and -jravel
overlays on the release rates of mercury from mercury
enriched sediments is summarized from Bonger and KnattaK
[155] as follows:
It was found in laboratory studies that overburden
layers of sand or gravel 6 cm thick prevented the release ot
mercury from the underlying enriched sediments. Layers less
than 6.0 cm thick were less effective in preventing mercury
loss from the sediments. Little differences were ouserv^d
in the rate of release from organic or inorganic sediments.
It was noted that Tubificidae worms when present in the
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sediments in large numbers apparently were responsible for
the vertical transfer of mercury. This suggests that
additional coverage of mercury enriched sediments may be
required in areas where sludgeworm activity is hign.
Although field tests were not conducted the approximate
cost of applying this abatement procedure in a
representative field situation were calculated. The area
selected for economic analysis was the Trenton Channel of
the Detroit River near Wyandotte. Cost estimates tor
treating .8, 10.1 and 20.2 hectares of mercury contaminated
sediment with 7.6 cm of sand overlay are listed in Taoles b
and 9. This cost evaluation is preliminary, and such site-
dependent factors as local transportation, sediment
characteristics, topography of the area, water currents and
depth, weather conditions and the availability of labor,
materials and hardware would affect the actual costs.
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142
Table 8
Estimated fixed/variable costs of distributing sand in an
area south of Wyandotte. I/
Fixed Costs ($);
Spreading Equipment System 20,000.00
(i.e. swivel piler, conveyor,
clam shell, fixtures, hopper, etc.)
Variable Costs;
Sand, dockside, per cubic meter 2.94
Tug boat and crex*, per 12-hour day 1,900.00
Deck scow, 612 to 765 m3 (500 - 1000 yd)
capacity per day 100.00
Equipment barge, per day 30.00
Labor, per day (2) 80.00
Equipment maintenance, per day 10.00
I/ Source: Bonger and Khattak (155)
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1U3
Table 9
Estimate of the cost involved in the application or 7.o cm
Of sand to .8, 10.1 and 20.2 hectares of sediment
contaminated with mercury J/.
Hectares
(Acres)
Fixed Costs($)
Variable Cost ($):
Sand
Tug Rental
Scow Rental
Barge
Labor
Maintenance
S/Total
Number of Days
m of Sand
(Yards of Sand)
0.8
(2)
20,000
1,670
1,900
100
30
80
10
"17790
1
566
(740)
10. 1
(25)
20,000
20,800
24,700
1,300
390
1,040
130
467360
13
7,037
(9,250)
tO. 2
(50)
20,000
4 1 ,000
47,500
.: ,^00
750
2,000
2bO
_ ______
25
14,145
(1tt,bOO)
J/ From: Bonger and Khattak (155)
Suggs, Petersen and Middlebrook (156) conducted
laboratory investigations ot the effectiveness of several
agents in removing mercury from the water column ana tne
underlying sediments. It was found that both elemental
sulfur and thio-organic compounds dispersed in recoverable
materials were capable of removing mercury. However,
elemental sulfur coated on a cotton meshwork was found to be
most effective, particularly in anaerobic sediments. It was
also found that the rate of removal of metallic mercury with
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144
elemental sulfur was proportional to the surface aren of the
"mercury getter".
Other mercury getters investigated, were poly vinyl
alcohol gel systems, paraffin, sulfur dispersed in paraffin,
sulfur tablets, cotton and. paper, plastics, paraffin-
thiourea, polyvinyl alcohol-cystene and iron oxides. Of
these only the poly vinyl alcohol nel systems contain inrr
sulfur or phenyl thiourea were found to bo effective in
removing mercury from contaminated v:ater and sediments, but
were not considered applicable where sediment contamination
levels were beloxv' 25 to 50 mcr/1. Cost for actual
application to field situations were not provided, but a
research-demonstration test plan has been proposed.
When a spill of hazardous substances occurs, the
contingency plan of the appropriate agencies must be
implemented immediately, frequently under adverse
conditions. Such an event occurred in Pond Lick reservoir,
Ohio, in 1971. The following summary of that experience is
condensed from reports prepared by PycJ-man, Edgerly,
Tomlinson and Associates, Inc. (157) and by Nye (158) of the
Ohio Department of Natural Resources.
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1U5
The Pond Lick Lake Incident - A Case S^udy
On June 2, 1971, Pond Lick Keservoir (known locally as
Shawnee Lake) near Portsmouth, Ohio was maliciously poisoned
with about U.5U liters of an endrin solution mixed with
strychnine treated corn. Pond Lick Lake is aoout JOU meters
long and approximately 75 meters wide at its widest point,
with maximum and average depths ot 12 and U.5 meters,
respectively. Fortunately at the time of the poisoning, the
lake was thermally stratified, thus restricting tne toxic
substances primarily to the epilimnioru
The effects of the poison were immediately apparent..
The entire fish population was destroyed, and the only
aquatic vertebrates surviving were tadpoles which were
apparently unaffected by the pesticide.
Pond Lick Lake discharges to the Ohio River via Poaa
Lick Creek and Turkey Creek. The total distance separating
the lake from the Ohio River is less than 16 kilometers.
Cincinnati, on the Ohio River about 160 kilometers below the
confluence point, was vitally concerned about its water
supply.
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1U6
As a means of containing t.he pesticide within tae lake,
the spillway was sandbagqed and an earthen dan. wa^ built
upstream on the inflowinq Pond Lick Creek. Tne creek was
then diverted around the lake via a 25.4 cm aluminum pipe
and two 13,620 liters per minute pumps. Paqs of activated
carbon were added to the spillway to remove the pesticide
seeping through, and the seepage was pumped hack into tne
lake.
At the time the spill was discovered endrin
concentrations of 9 mg/1 were present in tne epilinrnion
waters with lower concentrations below the thermocline.
Strychnine was not detectable in the lake.
Since endrin is extremely toxic, even in concentrations
as low as 0.2 mg/lr is highly stable and can be conceritrateu
biologically by factors of 10,000, it was imperative that
essentially all the endrin be removed as rapidly as
possible. A heavy rain would overload the by-pass system
releasing the contaminated lake water to the receiving
stream.
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1U7
Suggestions considered for resolving the problem were as
follows:
1. Dilution
2. Spray irrigation
3. Adsorption - fcentonite, fly ash
U. Biological removal
a. Sewage
b. Fish
5. Chemical treatment
a. Cracking
b. Oxidation with ozone
6. Adsorption and filtration through activated carbon,
7. Physical removal by use of tank trucks.
8. Filter through alfalfa hay.
Most of the suggestions were discarded as impractical or
ineffective.
An initial attempt was made to reduce the concentration
of endrin by broadcasting approximately 3,178 kg of 40 mesn
activated granular charcoal over the lake. This proved to
be ineffective as there was insufficient contact time before
the charcoal settled out.
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1U8
A pilot plant was next constructed of a U5.7 cm diameter
pipe, 2.U meters high and filled with activated cnarcoal.
Water from the lake was run into the bottom and out the top
of the cylinder. This system proved to be very etreceive as
the endrin concentration of lake water which passed through
the column was reduced to near zero.
A large treatment, plant was then designed based upon trie
success of the pilot plant. A channel filter was
constructed consisting of a 122x2UUx549 cm wooden box
containing gravel and a 1.8-meter deep charcoal bed. Water
was pumped through the bottom. The filter was effective but
slow, with a flowthrough rate of about 30U liters per
minute. It was discovered that underground springs were
feeding the lake faster than it could be filtered, so an
additional charcoal filter was constructed in the spillway
outlet, with the filtered water diverted into a stilling
flume and retained until analysis indicated that endrin
concentrations were below 0.1 mg/1.
Analysis of the lake sediments indicated that enurin was
being adsorbed by sedimented organics. Since the la*e level
was not being decreased as rapidly as desired, another
filtering device, constructed to hold 166 bales ot hay, was
-------
If!
149
designed based upon another pilot plant study. This syste
could handle approximately 5.7 m^ per minute with no
evidence of endrin detectable in the discharge, hnen the
lake was eventually drained, endrin concentrations in tne
sediments along the bank were approximately 100 mg/ky.
Concentrations in the lake bottom sedimctnts were much lower.
The bottom and sides of the lake were cleaned and
scraped, and the spoils disposed ot in a prepared area
outside the watershed. Approximately U,9UO cubic meters of
sediment were distributed over a .8 hectare spoil area to a
depth of U5.7 cm and mixed with clay. Three months alter
the poisoning event, the lake was fertilized, the DanKs
reseeded, the lake refilled and fish restocked. Total
estimated costs were $100,000.
The Pond Lick Lake incident serves to demonstrate tr.at
in the event of a hazardous substance spill, no matter how
hopeless the case appears to te, a possible solution may
exist. In the Pond Lick Lake case the cooperative ertort of
Federal, State and county governments and various local
agencies, private consultants and industries proviuea a
solution to the problem.
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150
The control of hazardous substances in the aquatic
environment has been the target of efforts by industry,
universities and governments. The various aspects o± trie
problems are discussed in the Proceedings of the 1972
National Conference on Control of Hazardous Materials Spills
(159),
POSSIBLE LAKE PROTECTION MANAGEMENT CONSIDERATIONS
Several state and local governments have established
statutes dealing with various aspects of lake management and
rehabilitation as a means of protecting inland lake
environments. Kusler (160) has summarized the state and
local statutes which establish preventive or remedial
programs, lists applicable statutes and sets out examples of
representative statutes. Kusler (160) points out that
explicit statutes authorizing specific state or local
programs for lake protection, management and rehabilitation
are rare, and that protection and iranagement estimates are
often badly fragmented among several state agencies ana
local units of government. This fragmentation of efforts
coupled with high costs and lack of technical expertise have
-------
151
discouraged comprehensive lake protection, management and
rehabilitation efforts (160).
Problems relating to lake shore development regulations,
shoreland management including economic impacts ot
artificial lake development and legal problems of property
owners associations are addressed in Various Inland Lake
Renewal and Shoreland Management Demonstration Projecc
Reports (161 - 165).
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152
Section V
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97. McGauhey, P. H., P. E. Eliasson, G. Pohlick, A. G.
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98. Levin, G. V. and J. M. Barnes. 196U. Harvesting or
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99. Anon. 1957. Sewage stabilization ponds in trie Dax.otas.
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100. Neel, J. K., J. H. McDermott, and C. A. Monday, Jr.
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-------
163
101. Bush, A. F., J. D. Isherwood and S. Fodqi.
Dissolved solids removal frcm waste- water by a-Ljae.
Jour. San. Snq. Div. , Am, Soc. Civil Ena. t>^,
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102. Boqan, R, H. 1961, The use of aiqae in removing
nutrients fronr domestic sewage. In: Alqae ani
metroplitan wastes. TR W61-3, [J, S. Public Health
Service, cinn. , Ohio.
103. Oswald, E, J. , C. G. Golueke, H. c. cooper, H. K, crje,
and J. c, Brenson. 1962. viator reclamation,
alqal production and methane f prrrenta^ ion in vva^te:
ponds. Manuscript No. 25, Int. Conf. W^ter Poliunon
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104. Gates, W. E. and J. A. Borcharat. 196U. Nitrogen dr^a
phosphorus extraction from domestic waste water
treatment plant eftluents by controlled alijai
culture. Jour. Water Pollution Control Ft\i. Ju:«*4j.
105. Livermore, D. 19SU. Harvestinq underwater weeds.
Water Works Ena. Feb. pp. 118-120.
106. Livermore, D. F. and W. E, Wundcrlich. 1969.
Mechanical removal of orqanic production from
waterways. In: Eutrophicat ion: causes,
consequences, correctives. Print inq and Publ.
Office, N.A.S., Washington, D. C.
107. Yount, J. L. and H. A, Grossman, Dr. 1970.
Eutrophicat ion control by [ lant harvesting, J.^ci
42(5) :R173-P1R3.
108. Bruhn, H. D., D. F. Livermorr, and P . O. Aboaba. j.970.
Physical properties and processir.q characteristics or
macrophytes as related to mechanical harvesting.
Paper #70-582. Am. Soc. Aqr, Engineers, St. Jose:>it,
Michiqan (also avail, from ttTIS as PB 19B
109, Nichols, S. A. 1971. The distribution and controx or
macrophyte nioirass in Lake Vvinqra, Wisconsin A
Resources Center, Madison. Final Completion D
OWRR B-019-WIS (4) . (Also avail, from NTIS as
-------
16U
110. Bagnall, L. O. , T. W. Casselman, J. W. Kesterson, J. F.
Basleyr and H. E, Hellwiq. 1971. Aquatic toraye
processing in Florida. Paper #71-536. Am. 6oc. Ayr.
Eng. OWRR A-017-FLA(2) .
111. Koegel, R. G., H. D. Bruhn, and D. F. Livermore.
Improving surface water conditions through control
and disposal of aquatic vegetation. Phase I:
Processing aquatic vegetation for improved Handling
and disposal or utilization. Wise. Water resources
Center, Madison, Technical Completion Report. UWh ii-
oia-wis(U) .
112. Boyd, C. E. 1971. The Limnoloqical role of aquatic
macrophytes and their relationship to reservoir
management. In: Reservoir fisheries ana limnology.
Special publ. #8 Am. Fisheries Soc. Washington, D. C.
pp. 153-166.
113. Goodson, J. B. and J, J. Smith. 1970. Treatment ot
citrus processing wastes. Water Pollution control
Research Series *12060-10/70. EPA, Water Duality
Office, Contract WPRD 38-01-67,
11U. Mulligan, K. F. 1969. Management of aquatic vascular
plants and algae. In: Eutrophication: causes,
consequences, correctives. Printing and Puol.
Office, MAS, Washington, D. C.
115. Lange, S. R. 1965. Commercial possibilities ot dehydrated
aquatic plants. Southern Weed Conference, proceedings
18:543-551.
116. Bailey, T. A. 1965. Commercial jossibilities of
dehydrated aquatic plants. Southern Weed
Conference, Proceedings 18:543-551.
117. Aboaba, F. O. 1971. Physical processing characteristics
of some aquatic macrophytes. PhD. Thesis, Univ. Wisconsin
(Avail, as OWRR B-018-WIS ( 3) ) .
118. Cifuentes, J. 1971. Screw press design parameters for
dewatering water hyacinth (Eichornia crassipes) . M.
S. Thesis in Engineering, Univ. Florida, Gainesville, Dept,
Agr. Eng. (WRSIC accession #W 72-03232.)
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165
119. Abou-El-Fadl, M. , s. G. fcizk, A. F. Abciel Ghani, M. K.
El-Mofty, and M. F. A. Khadr. 1970. Utilisation of
water hyacinth as an organic iranure with social reference
to water-borne helminths. J. Microbiol. U.A.K. J:2?-3U.
120. Lee, G. F. 1970. Eutrophication. Univ. Wisconsin
Water Resources Center, Madison, Occasional Paper §2,
Eutrophication Information Program.
121. Rogers, H. H., Jr. 1971, Nutrient removal oy water
hyacinth. M. S. Thesis, Auborn Univ., Alaoama.
WRSIC accession #W72-04776.
122. Gerloff, G. C. and P. H. Krombholz. 1966. Tissue
analysis as a measure of nutrient availability for
the growth of angiosperm aquatic plants. Limnoi. ana
Oceanogr. 11:529-537.
123. Cottam, G. 1969. Changes in water environment
resulting from aguatic plant control. Proceeuin«js of
meeting, joint industry/Government Task Force on
Eutrophication. Univ. Wisconsin, Madison, Nov. 2<«-^5,
19f>9.
12U. Steward, K. K. 1970. Nutrient removal potential of
various aquatic plants. Hyacinth control Journal
8:3U-35.
125. Taylor, P. G., R. P. Dates, and R. C. Robbings. 1971.
Extraction of protein from water hyacinth. hyacinth
Control Journal 9:20-22.
126. Seidel, K. 1968. Elimination von Schmutz-uria
Ballaststoffen aus belastet-en Gewassern durcn
hohere Pflanzen (Elimination of substances ot
mud and ballast from waters by higher plants).
Zeitschrift Pitalstoffe-zivilisations KranKheiten Mr. 4.
127. Kiefer, W. 1968. Pflanzen tioloqische Reiniyung
von Abwasser (Biological wastewater treatment with
plants). Umschau:210.
128. Greer, D. E., and C. D. Ziebell. 1972. Biological
removal of phosphates from vater. JWPCF UU:
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166
129. Corey, R. B., A. D. Hasler, F. K. Schraufnagel, and T.
L. Wirth. 1967. Excessive water fertilization:
Report to water subcommittee, Natural Resources
Committee of State Agencies. Madison, Wisconsin
(Unpublished).
130. Bailey, W. M., and R. L. Boyd. 1972, Some observations
on the white amur in Arkansas, Hyacinth Control
Journal 10:20-22.
131. Opuszynski, K. 1972. Use of phytophagous fisa to
control aquatic plants. Aquaculture 1:61-74.
132. Sport Fishing Institute Bulletin. 1972. Grass carp
problem. No. 240. Washington, D. C,
133. Hasler, A. D., and E. Jones. 1949. Demonstration of tne
antagonistic action of large aquatic plants on al^ae
and rotifers. Ecology 30:359-364.
134. Porter, K. B, 1972. Control of natural phytoplanxton
populations by grazing zooplankton. (Abstract or
paper presented at AAAS-Ecological Society) Bull.
Ecol. Soc. Am. 53:9.
135. Mattox, K. R., D. Stewart, and G. L. Floyd. 1972.
Probable virus infections in four qenera of green
algae. Can. Jour. Bot. 18:1620-1621.
136. Safferman, R. S., and M. E. Morris. 1963. Algai virus:
isolation. Science 140-679-680.
137. Padan, E. and M. Shilo. 1969. Distribution of
Cyanophages in natural habitats. Verh. International
Verein. Limnol. 17:747-751.
138. Shilo, M. 1971. Biological agents which cause lysis ot
blue-green algae. Mitt. International Verein. Limnol.
19:206-213.
139. Cappleman, L. E. 1972. Detached leaf culture of
Eichornia crassipes and application to the culture
of its pathogens. M. S. Thesis, Florida Atlantic
University, Boca Raton (unpublished).
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167
140. Sculthorpe, C. D. 1967. The biology of aquatic vascular
plants. Edward Arnold (Publishers) Ltd. , London.
1U1. Gillies, P. (Ed.) 1972. The Water Hyacinth. Water
News Letter 1U:2. Water Information Center, Inc.
Publ. Port Washington, L. I., N.Y.
142. Coulson, J. R. 1971. Prognosis for control of water
hyacinth by arthropods. Hyacinth Control Journal
9:31-34.
143. Hawkes, R. B. 1965, Domestic phases of program designed
to use insects to suppress alligator weed. Proc. ii.
Weed Conf. 18:584-585.
144. Baloch, G. M. , A. G. Khan, and M. A. Ghani.
Phenology, biology and host-sepciticitty ot some
Stenophagous insects attacking Mvriophvllum spp. in
Pakista. Hyacinth Control Journal 10:12-16.
145. Blackburn, P. D. , and L. W. Weldon. 1965. A f resn water
snail as a weed control agent. (Abstract) Proc. S.
Weed Conf. 18:589.
146. Sguros, P. L. , T. Monkus , and C. Phillips. 1965.
Observations and techniques in the study of tne
Florida manatee - reticent but superb weed control
agent. Abstract. Proc. S. Weed Cond. 1.8: 588.
147. Fitzgerald, G. P. 1971. Algicides. Literature
Review No. 2, Eutrophication Information Program,
the University of Wisconsin Water Resources Center.
148. Fitzgerald, G. P. 1966, Use of potassium permanganate
for the control of problem algae. Jour. Ainer. Water
Works Assoc. 58:609-614.
149. Timmons, F. L. 1970. UNESCO Meeting on Ecology and
Control of Aquatic Vegetation, December 16-18, 196 a.
Paris. Hyacinth control Journal fl(2):23-26.
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168
150. Lambou, V. W. 1972. Problems of mercury emissions into
the environment of the United States. Report to tne
Working Party on Mercury, Sector Group on Unintended
Occurrence of Chemicals in the Environment, OrlCD,
Environmental Protection Agency,
151. Jernelov, H. 1969. Conversion o± mercury compounds.
In: Chemical fallout. Charles C. Thomas, Springfield,
Illinois.
152. Trukayama, K. 1966. The pollution of Minamata Bay and
Minnemata Disease. Adv. Disease. Adv. Water Pollution
Research, Proc. Int. Conf. 3:153-180.
153. Study group on mercury, hazards. 1970. Hazards of mercury.
Special report to the secretary's Pesticides Advisory
Committee, Dept. of Health, Education and weitare ana
Environmental Protection Agency.
15U. stephan, D. G. 1971. Trip report: Finland and Sweden,
Feb. 21-25, 1971. Assistant Commissioner, Research
and Development, Water Quality Office, Environmental
Protection Agency.
155. Bongers. L. H. and M. N. Khattak. 1972. Sand and gravel
overlay for control of mercury in sediments. Kesearcn
Institute for Advanced Studies, prepared for tne
Environmental Protection Aqency, Washington, D. C.
156. Suggs, J. D. , D. H. Petersen and J. B. Middlebrook, Jr.
1972. Mercury pollution control in stream and lake
sediments. Advanced Technology Center, Inc. Prepared
tor the Environmental Protection Agency, Ortice of Research
and Monitoring, Washington, D. C.
157, Pyckman, Edgerley. Tomlinson and Associates, Inc.
Pesticide poisoning of Pond Lick Lake, Ohio
investigation and resolution, June 2 - July 5, 1971.
Final report prepared for the Environmental
Protection Agency, Division of Oil and Hazardous
Materials, OWP, Washington, D. C.
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169
158. Nye, W. R. 1972. The hazarcous material spill
experience in Shawnee Lake, Ohio - a cas<°
In: Control of hazardous materials spills. Proc.
1972 Nat. Conf. on the Control of Hazaroous Materials
Spills, March 21-23, 1972, Houston,
159. Control of hazardous materials S[ills, 1972. Proc.
Nat. Conf. on the Control cf Hazardous Materials
March 21-23, 1972, Houston, Texas.
160. Kusler, J. A. 1972. Survey: lake protection ar.u
rehabilitation leqislation in the United States.
Inland Lake Renewal and Shcreland Manaqemerit
Demonstration Project Report. Univ. of uisc,
Madison.
161. Yanqqen, D. A. 1971. Preservinq lakes by protectin-j
their shorelarids. In: Prcceedinqs Workshop
Conference on Reclamation of Maine's Dyinq ^ais.e»,
Univ. of Xaine, Banqor, March 24 and 25, 1971. Conf.
Report No. 2, Water Resources Center, Univ. ot i-iaine,
Orono.
162. Klessig, L. L. and D. A. Yanqqen. 1972. Wisconsin Lake-
Shore Property Owners Associations: Identification,
description arid perception of lake problems. Inlana
Lake Renewal and Shore land iVanauement Demonstration
Project Report, Univ. of hisc. , Madison.
163. Kusler, J. A. 1971. Artificial lakes and lana
subdivisions. Report from Wisconsin Law Review,
Vol. 1971, No. 2, Univ. of Wise., Madison.
16U. Lejeune, H. 1972. Economic impacts of artincial ia*e
development: Lakes Sherwood and Camelot - a case
history. Inland Lake Renewal and Shorelanci Management
Demonstration Project Report. Univ. of Wise., Maaisoa
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170
165. Yanqgen, D. A. and Z. L. Zigurds. 1972. Leyal problems
of property owners1 associations for large water-
oriented recreational housing complexes. Inland Lake
Renewal and Shoreland Management Demonstration
Project Report. Univ. of Wise., Madison.
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171
APPENDIX
Section VI
LAKE PROBLEMS
SOURCES OF WATEP QUALITY PROBLEMS IN LAKES
Water quality problems have resulted as increased
amounts of wastes have been introduced to aquatic receiving
systems. Molecules of diverse chemical structures have L»een
synthesized resultinq in compounds which are refractory to
dcqradation. The ability of microorqanisms to metdDoliiie
pollutants to carbon dioxide and water and thus to remove
them from the aquatic environment is the. primary biological
method for "self purification" of waters. As organisms
advance evolutionally, the inherent ability to assimilate
and deqrade new and diverse products is rabidly diminished.
Evidence of this is seen in the alarming levels ot certain
chlorinated hydrocarbons. Although contaminants may
originate from a variety of sources, they can usually be
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172
broadly classified as industrial, municipal or agricultural
wastes.
Industrial Wastes
Industrial wastes often create unique problems in cne
aquatic environment. They are frequently in the rorm or
liquid containinq substances which are aifticult it not
impossible to remove from drinkinq water. The magnitude of
the problem is brought to liqht. by the fact that tnero are
approximately 240,000 water usinq establishments in tne
•a
United States which consume 75,700 mj (20,000,000 gallons)
or more water (1). Industrial waste water efrluent has
three t.o four times more oxyqen-deirandinq wastes than tue
total sewered population in America (2). As industries
expand and diversify the attendant problems ot industrial
effluents increase at a proportional rate. Atmospneric
rain-out resultiriq from industrial stack and automobile
emissions also contribute to the contamination ot waterways.
No detailed inventory of industrial wastes is
however, as seen in Table I, the airount of wat^r useu ana
waste qenerated is enormous. Water and airborne wastes
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173
contain organic and inorganic solids, suspended material,
toxic substances, and biological grcwth stimulants.
The magnitude of industrial waste loading can be
illustrated by using thermal pollution as an example of tne
total problem. The electric power industry, the single
largest producer of waste heat, and a contributor or other
pollutants, is increasing at a rate of 7.2 per cent
annually, almost doubling every ten years (U). As seen in
Table II, this trend is expected to continue. Otner
industries also require water for cooling purposes (faule
III). The metal, chemical, petroleum and coal, paper, tood,
and various manufacturing industries are among those
requiring large quantities of cooling water.
It has been estimated that by 1980 electric power
cooling operations alone will require the equivalent of one-
fifth the total fresh water runoff to the United states (4).
However, the thermal loading associated with power
generation is only one example of water quality degradation
caused by industry. Other industries have effluents wnicri
can be more difficult to deal with.
-------
TABLE I
Estimated Volume of Industrial Wastes
Before Treatment, 19 f 4 I/
Waste
Water
Waste
Water
Volume Volune
(billion (billion
Food and kindred products
Meat Products
Dairy Products
Canned & frozen food
Sugar refining
All other
Textile mill products
Paper & allied products
Chemical 6 allied products
Petroleum & coal
Rubber & plastics
Primary metals
Blast furnaces &
Steel mills
All other
Machinery
Electrical cmachinery
Transportation equipment
All other manufacturing
All manufacturing
For comparison: Sewered
population of the U.S.
I/ Columns may not add, due to
27 120,000,000 persons times 0.
T/ 120,000,000 persons times 0.
V 120,000,000 persons times 0.
m3)
2.61
0.37
0.22
0.33
0.03
0.133
0.53
7.19
7.19
4.92
0.61
16.28
13.63
2.80
0.57
0.34
0.91
1.70
49.58
20.06
gallons)
(1
(3
(1
(4
(3
(13
(5
(690)
(99)
(58)
(87)
(220)
(220)
(140)
,900)
,700)
,300)
(160)
,300)
,600)
(740)
(150)
(91)
(240)
(450)
,100)
,300)2/
Process
Water
Intake
(billion
m3)
0.98
0.20
0.05
0.20
0.42
0.16
0.42
4.92
2.12
0.33
0.07
3.79
3.29
0.49
0.09
0.11
0.22
0.72
14.00
-
Process
Water
Intake
(billion
gallons)
(260)
(52)
(13)
(51)
(110)
(43)
(110)
(1,300)
(560)
(88)
(19)
(1,000)
(870)
(130)
(23)
(28)
(58)
(190)
(3,700)
-
S uspended
BOP
(million
kg)
1952
290
18
544
685
304
404
2678
4403
227
18
204
76
145
27
31
54
177
9988
3314
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2
6
2
8
6
2
1
6
8
0
2
3
6
3
2
8
5
1
0
2
BOD
(million
pounds)
(4,300)
(640)
(400)
(1,200)
(1,400)
(670)
(890)
(5,900)
(9,700)
(500)
(40)
(450)
(160)
(320)
(60)
(70)
(120)
(390)
(22,000)
(7,300)3/
Solids
(million
kg)
2996.
290.
104.
27.
2270.
49.
— —
1362.
862.
208.
22.
2137.
1952.
195.
22.
9.
—
422.
8172
3995
4
6
4
2
0
9
0
6
8
7
8
2
2
7
1
2
rounding.
452 m
0757 ko
0808 kg
(120
(1/6
(0.2
gallons)
pound)
pound)
times 365
times 365
times 365
days.
days.
days.
Suspended
Solids
(million
pounds)
(6,600)
(640)
(230)
(600)
(5,000)
(110)
(3,000)
(1,900)
(460)
(50)
(4,700)
(4,300)
(430)
(50)
(20)
(930)
(18,000)
(8,800)4/
Source: (3)
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175
Table II
U.S. Electric Power - Past Use, Future Estimates
In billion
Year Kilowatt-hours
1912 12
I960 753
1965 1,060
1970 1,503
1975 2,022
1980 2,754
1985 3,639
Source: (5)
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176
T£BLE III
Use of Cooling Water by U.S. Industry
Industry
Electric power
Primary metals
Chemical and allied products
Petroleum and coal products
Paper and allied products
Food and kindred products
Machinery
Rubber ancl plastics
Transportation equipment
All others
Coolinq
VJater Intake
(billions)
154.0
12.8
11.8
4.6
2.3
1.5
0.6
0.5
0.4
1.0
(billions of
gallons)
(40,C80)
(3,387)
(3,120)
(1,212)
(607)
(392)
(164)
(128)
(102)
(273)
Percent
of ^ota
81.3
6.8
6.2
2.4
1.2
0.8
.3
.3
.2
.5
total
189.5
(50,065)
100.0
Source: (5)
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177
Municipal Wastes
Municipal waste treatment accounts for the disposal of a
heterogeneous variety of liquid and solid material wnj.cn
comes from domestic (55X) and industrial (U5%) facilities
(tt). Added to this constant, waste load is the periodic
storm sewer runoff, which in certain areas of the country
(Northeast, Midwest and Far West) may contain deicing
chemicals and organic and inorganic pollutants. Domestic
waste treatment sewers service approximately two-tnirds of
the total population (U). of this sewered population,
approximately 60 per cent have adequate treatment facilities
CO-
A major contribution of phosphates and nitrates to lakes
and reservoirs comes from municipal plants (U). In addition
to the inorganic nutrients are various organic compounds,
such as detergents, which can act as a substrate for a
variety of microorganisms. The organically and chemically
rich effluents serve as an ideal millieu for the growtn of
the endogenous bacteria in the receiving waters. It is the
growth of these normal inhabitants which lowers the
dissolved oxygen and is reflected as biochemical oxygen
demand (BOD).
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178
Agricultural wastes
Agricultural wastes in waters originate basically trom
either fertilizers and pesticides supplied to growing crops
or as wastes from livestock. Fertilizers contain
predominately nitrogen and phosphorus, which when applied to
the land, can wash into the aquatic environment. These two
nutrients stimulate the growth of algae, bacteria and
aquatic weeds leading to a shift in the normal aquatic lite.
Pesticide runoff is another problem associated with, out
not exclusive to, agricultural activities. Productivity
reportedly has increased with the increased use ot
insecticides and the consequent reduction of plant pests.
However, in some areas, the cost ecologically has been
manifested in either the elimination of or decrease in
numbers and diversity of certain aquatic organisms. As tne
population increases with attendant demands for more iooa a
continued, if not increased, pesticide use will be retired.
Feedlot wastes are a potential contributor to tne
pollution of waters in various areas ot the country. Modern
methods for raising beef cattle, poultry and swine, along
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179
with dairy farm operations produce concentrated waste
sources of potential water pollution. The animal wastes
produced today are estimated to be the equivalent ot trie
waste produced by 2 billion people (U). This figure does
not necessarily mean that a proportional amount 01 animal
waste ends up in water, since much does not reach tne
aquatic ecosystem. However, it is a measure of tne
pollution potential.
Miscellaneous Sources
Mine drainage
Acid drainage comes from mines where the water and air
mix allowing the growth ot sulfur oxidizing bacteria. As a
consequence of this growth sulfuric acid is produced
resulting in a pH, in extreme cases, of less than one. It
has been estimated that in the Appalachia region, where 75
per cent of coal mine pollution occurs, about 168,000
kilometers of streams are polluted (U). Other mining
operations for phosphate, iron, copper, gold and aluminum
also are responsible for acid mine discharge.
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180
Oil and Hazardous Materials
Pollution of the aquatic environment due to oil
hazardous materials spills has grown steadily in the past
years. As seen in Table IV, the number of spills over
15,900 1 (100 barrels) increased dramatically in a period of
one year. The number of spills is expected t.o increase as
the flow of oil to refineries increases to meet rising luel
demands. Disposal of spent motor oils and lubricants also
presents a problem. It has been estimated that 1,J30,000
kiloliters of used oil per year have to be disposed ot by
gas service stations (4).
TABLE IV - Number of Reported Oil Spills in U.S. voters
over 15,900 1 (100 Barrels)
1968 1969
Vessels 347 532
Shore facilities 295 331
Unidentified 72 144
Total 714 1,007
Source: (6)
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181
Watereraft Wastes
Pollution resulting from sewage discharged from
watercratt is primarily of health significance ratner tnan
organic or oxygen depleting significance. It has oeen
suggested that the total potential sewage from vessels is
equal to a town of 500,000 people (U). However, sewage
waste disposal from vessels can present a problem in
confined areas such as boat harbors and marinas.
IMPACT OF CONTAMINANTS ON LAKE ENVIRONMENTS
Impairment of lakes can result from an isolated instance
of the introduction of a contaminant, such as occurs uuring
an accidental spill, through continuous or intermittent
industrial or municipal point source discharges, or through
surface runoff and contributions from tributary streams and
ground waters.
The nature of contaminants and their effects on lake
environments vary widely. In general, the various
contaminants can be grouped into categories based upon tiie
manner in which they affect a lake ecosystem. The major
groups are the organic.wastes, inorganic nutrients, silts
and sediments, toxic substances, and heated waters. Other
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182
contaminants include radioactive wastes, various non-toxic
salts, and many others which produce a *ide ranae 01 etrects
on lake environments. The impact of each of the major
groups of contaminants is discussed below under trie
respective headinqs of eutrophication, sedimentation,
thermal problems and selected toxic substances. Kaaioactive
wastes and non-toxic salts are briefly discussed unaer the
heading of miscellaneous problems.
Eutrophication
Eutrophication may be broadly defined as nutrient or
organic matter enrichment, or both, that results in niqn
biological productivity and a decreased volume witniu a
ecosystem. Eutrophication is, therefore, a process by wnicn
a lake gradually evolves from a condition of low
productivity (oligotrophic) to a highly productive condition
(eutrophic). Organic matter and nutrients are carried into
the lake by runoff and leaching frcm the drainage juasin,
stimulating increased biological productivity of all Kinds.
Products of erosion carried to the lake, ana excessive
quantities of organic matter, both plant and animal,
produced within the lake, lead to a gradual filling-iri, and
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the lake becomes shallower and smaller. The waters
consequently become generally warmer. Footed aquatic plants
take over increasingly more space, their dead remains
accelerating the filling ot the basin. Eventually tne la*e
becomes a marsh, upon which terrestrial vegetation
progressively encroaches until the lake ceases to exist,
being replaced by a dry-land environment. The laKe tnen,
not only evolves from oligotrophy to eutrophy, but, it tne
aging process is permitted to proceed to completion,
eventually is subjected to total extinction.
Natural and Accelerated (Cultural) Futrophicatiion
The gradual enrichment and aging of lakes is a natural
process which takes place under completely natural
conditions, in the absence of man, provided that a
sufficient nutrient supply is available from the drainage
basin. For lakes situated within a relatively sterile
drainage area, the aging process may span geologic time.
Other lakes, subject to heavy nutrient loading from
naturally fertile drainage basins apparently were higril>
eutrophic prior to their exposure to civilization.
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The role of man in the eutrophication process may
completely override natural forces. Many lakes have been
observed to become enriched and to age very rapidly trom uie
effects of domestic or industrial waste disposal, or from
drainage basin disruptions or alterations resulting trom
man's activity. Nutrient flux to lakes can be increased
manytold by, for example, the input of nutrient-containiay
wastes, agricultural fertilization, clearing of forest
lands, and roadbuilding and other construction. Many lakes
exposed to increased nutrient input are currently exhibiting
symptoms of rapidly increased rates of eutrophication; triis
condition is referred to as accelerated or cultural
eutrophication, and it is an ever-growing problem in tne
United States and other countries.
Consequences of Eutrophication
The progressive eutrophication of a lake results in
distinct physical, chemical, and biological changes,
generally in the direction of impairment of the lake*s
utility to man. Oligotrophic lakes have the highest 4uality
water (although perhaps net the best tishing), and tne water
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is well suited to a variety of uses, Oligotrophic ldK.es
good multi-purpose lakes.
Very definite changes in the quantity and quality or tne
biota occur as eutrophy proceeds. With the increased
productivity associated with accelerated rates of
eutrophication comes the filling of the basins with
organic materials and sediments resulting in an i
oxygen demand on the overlying waters. The increased ox/gen
demand may result in total depletion of oxygen in the cooler
bottom waters during the summer, accompanied by an increase
in the products of respiration and decomposition, namely
carbon dioxide, methane, and hydrogen sulfide. Tnese
developing anaerobic conditions result in replacement ot
existing benthic organisms with less desirable types, dua
cold-water species of fish, such as trout and salmon, are no
longer able to exist; they are replaced ly forms tolerant of
higher temperatures. Curing the winter, under heavy ice.- and
snow cover, shallow eutrophic lakes may be subjected to
complete oxygen depletion. As a result entire fish
populations may be eliminated, as frequently happens in tne
northern states.
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In addition to restricting fish populations, hignly
eutrophied lakes are undesirable aesthetically and with
respect to water use. Alqal blooms produce taste and odor
problems, and create unsightly surface scums which
discourage water contact recreational activities. Dense
growths of rooted aquatic plants may accompany, or occur in
place of, the nuisance algal blooms. Such intense plant
production greatly inhibits use of the water for swimming,
fishing, or boating. Accumulation of algal mats ana dense
weed growths are most pronounced near shore, where mar^s
contact with the water is greatest. The accumulated algal
masses begin to decay in a short period of time, resulting
in extremely foul-smelling conditions. Excessive plant
production, then, can render a lake virtually unfit for
recreational purposes or shoreline development.
In addition to their deleterious effects on aesthetic
and recreational aspects of lakes, the excessive growth of
aquatic plants can seriously affect water quality. Large
quantities of planktonic algae frequently, and to a serious
extent, increase the rate of clogging of sand filters at
water treatment plants.
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Probably even more serious is the increased frequency of
taste and odor problems resulting from algae in eutrophic
lakes. These can originate from either living or dead
algae, or from the fungi which grow on algae remains.
Tastes and odors may be produced fcy members of all the major
algal groups: the blue-greens, greens, diatoms, and
flagellates. No one group is responsible.
Still other water quality problems resulting trom
eutrophication are increased color in the water, resulting
from plant growth, and concentrations of iron, manganese,
and sulfide which may occur as the result of oxygen
depletion.
Certain blue-green algae have fceen shown to have toxic
effects on animals. Domestic animals, such as cattle arid
sheep, as well as fish and aquatic invertebrates, may be
susceptible to toxic substances excreted by algae of tnis
group. Water in which certain tlue-green algae have Dloomed
may produce death in mammals and fish even when tne algal
cells themselves are excluded. There is also evidence that
allergic reactions and gastrointestinal disturbances may
result in humans from contact and ingest ion of la*e water in
which algae exist- in blocm proportions.
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Sedimentation
Sediments are an integral part of lake ecosystems,
providing habitats for benthic organisms and serving di a
pool for nutrients necessary for aquatic plant growtn. Ion
exchanges and nutrient transport tf.tv/een the mud ana wat^r
significantly affect the lake(s productivity. Accelerated
erosion and subsequent deposition of sediments in lakes can
result in a degradation of these natural ecosystems. In
terms ot volume, sediment is today's greatest water
pollutant. It reduces the storage capacity of reservoirs,
fills lakes and ponds, clogs stream channels, buries
habitats and increases turbidity.
Effects of Sediment
Sediments influence the physical, chemical ana
biological processes occurring in lakes. Perhaps one ot the
most obvious is the filling of lakes and impoundments by
sedimentation thus restricting the usetul life of tne water
body. A detailed survey of 148 artificial lakes (7)
revealed the average annual loss of water retaining volume
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which as shown in Table V, varies between 0.5 to 2 percent
annually.
Table V
ANNUAL LOSS OF RETAINING VOLUME FOR 1U8 LAKES
No. of Lakes % Annual Volume Loss
3U 0.5
39 0.5 to 1.0
39 1.0 to 2.0
36 2.0
Source: (7)
Suspended sediments increase turbidity and reuuce the
depth to which light penetrates below the water surrace thus
restricting the growth of photosynthetic flora ana reaucirig
the lake's productivity. Increased turbidity also affects
aauatic food chains by impairing the sight and food
gathering efficiency of predators. The European inland
Fisheries Advisory Commission (8) reports the effect ot
inert suspended solids on freshwater fish as shown in Table
VI.
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Table VI
EFFECT OF INERT SUSPENDED SOLIDS ON FRFSHV/ATER FISH
Concentration, Eftect
mq/1
25 No evidence of harmful ettects
25-80 Good to moderate fisnenes
80-UOO Good fisheries unlikely
UOO Poor fisheries
Source: (8)
High concentrations of suspended materials may also ue
deleterious to aquatic vertebrates by reducing their
resistance to disease, preventing the successful development
of eggs and larvae, modifying natural migrations ana
reducing the abundance of food. Buck (9) removed the fish
from 39 farm ponds having a wide range of turbidities, and
restocked the ponds with largemouth Mack bass (Microptcrus
salmoidesl , bluegill (LejDCjnis macrochirus) and red-ear
sunf ish (Lepomis micro.lojDhus) . After two growing seasons,
the fish crop was harvested and the effects of various
turbidity levels on reproduction were compared as seen in
Table VII.
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TABLE VII
EFFECT OF TURBIDITY OK FISH REPRODUCTION
Yield, kg/ha (Ib/acre) Turbidity, mq/1
181.2
105.5
32.9
(161.5)
(9U.O)
(29.3)
25
15-100
100
Source: (9)
Buck (9) also reported that larqemouth black
crappies (Pomoxis) and channel catfish (Ictalurug iuactat.usl
qrew more slowly in a reservoir where the water hdU an
average turbidity of 130 mg/1 than in another reservoir
where the water was always clear.
Lake sediments provide habitats for benthio organisms
including bacteria, fungi, algae, flagellates, cilidtes,
sponges, mussels, worms, insects and snails. Sorre ot tnese
orqanisms have commercial value, and others are essential
links in food chains which sustain tish, water fowl ana
other wildlife. When accelerated erosion resulting from
farming, timber harvest and other activities causes iieavy
sediment inputs to a lake, the benthic flora and tauiid
be blanketed with layers of silt, Feedinq qrounds and
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spawninq sites as well as entire populations may be
destroyed, causing radical changes in the lake ecosystems.
By the ion exchange process at the mud-water interface,
nutrients are either released to the bottom water or are
removed from the water by the sediments. These ion
exchanges are caused by oxidation-reduction (redox)
reactions. The oxidation potential of a solution is
determined by the type and proportion of oxidized and
reduced ions in the solution.
When oxygen is available to the lake bottom, the top
strata of its sediments are oxidized. This layer acts as a
barrier against diffusion from the mud to the water and
holds nutrients in the sediments. However,- when a lake's
benthos becomes anaerobic this layer becomes thinner ana may
disappear entirely. As the oxidized layer of sediments is
destroyed, nutrients in reduced form (i.e., Fe + + , Mn«-+, NH3
and P) are released from the sediments into the water ana
are available tor assimilation by the biota.
Suspended solids entering a lake may adsorb bota
nutrients and toxic materials removing them from possible
involvement in the food web as deposition of suspended
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particles occurs. Gumermar^s (10) study of sterile
sediments from Lake ^rie and Lake Superior demonstrated tnat
the maximum phosphate adsorbing capacity of the sediments is
in the top 3.5 mm, and is reduced to zero below 1u nuru
Gumerman (10) also found that the release of adsorbed
phosphorus from sediments will maintain sufficient
concentrations of phosphates to sustain alqal growths tor
some time after phosphate input has ceased. Anotner study
on phosphate equilibrium tetween reduced sediments and water
(11) revealed that sediments in a reduced state will adsorb
less phosphate than the same sediment in an oxidized state.
Consequently, under low oxygen tensions at the muu water
interface, phosphates are released into the water by
chemical reduction reactions and by a physical tendency oi
the sediment particles to adsorb fewer molecules and ions.
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Sources of Sediments
Lake sediments fall into two general categories,
depending upon their origin. Autochthonous sediments are
generated within the lake itself, and are often composed
primarily of decomposed aquatic plants. A highly productive
eutrophic lake will have a larger proportion of
autochthonous sediments than an oligotrophic lake.
Allochthonous sediments are transported into the lake from
an outside source. Under natural conditions these sediments
are generally the result of three geologic processes -
erosion, transportation, and deposition. Human activities
associated with forestry, agriculture, mining, uruan
development, highway construction, and channelization otten
tend to accelerate the natural geologic processes tnereby
increasing several fold the natural sedimentation rates or
lakes.
Timber harvesting operations may be responsible ror
increased sedimentation. On a steep forested slope in
Oregon clear-cutting with no roads increased sedimentation
three times more than that of a control slope (12). Erosion
on patch-cut areas with forest reads has reportedly
increased sedimentation more than 100 fold.
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Runoff from cultivated land carries a heavier silt load
than that from either forest or grassland. However, soil
conservation practices, including contour plowing and strip
cropping, have greatly reduced agricultural land erosion.
Strip mine runoff and erosion of mine tailings are a
major source of sediment in some areas. The annual sediment
yield from unmined areas of Cane Branch, Kentucky, averaged
about 8.8 metric tons per square kilometer (13). Erosion ot
mine spoil banks in this same drainage basin resulted in an
average annual yield ot 9,455 metric tons per square
kilometer, and erosion of abandoned coal haul roads at steep
grades was also severe.
Urban land development resulting in exposure of Dare
soil at construction sites is also a cause of accelerated
erosion. Yorke and Davis (14, 15) indicate that a direct
relation exists between the sediment yield of a basin ana
the area of land under construction, the season ot tne year,
slope of the land, and proximity cf construction sites to
stream channels. Streamflow and sediment data were
collected at gauging stations on Bel Pre Creek in Montgomery
County, Maryland, between 1963 and 1967. Pasture and
woodland dominated the landscape prior to March 1965,
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however, between March 1965 and August. 1967, 15 percent of
the watershed was developed into garden apartment ana
townhouse complexes. Suspended sediment discharged
increased 1U times as a result of this construction (1u,
15). A study on the effect of urbanization on sediment
yield in New Jersey (16) also suggested that yields are
proportional to the degree of urbanization. The low
population density pine barrens yielded U - 14 metric tons
of sediment per square kilometer per year, while the
urbanized Delaware River area yielded 9-35 metric tons per
square kilometer per year, and in the Philadelphia area, the
yield was up to 175 metric tons per square kilometer per
year. This corresponds to the 70 - 175 metric toas per
square kilometer per year sediment yield reported (17) for
the Washington and Baltimore urban and suburban areas.
Sediment transported by storm runoff was measured (18)
for 25 storm events on a 23.5 hectare watershed in
Kensington, Maryland. Between July 1952 and January 1962,
89 single family homes were built and 171 metric tons of
sediment per acre were lost from this watershed. It is
apparent that sediment yield is controlled by the combined
effect of runoff and vegetation cover, both of which are
affected by human use of the land.
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The extent of erosion and transportation ot soil exposed
by highway construction was studied (19) in a 11.6 square
kilometer watershed in Fairfax County. Virginia. Seaiment
yield was measured at gauging stations and revealed tuat,
with average precipitation, erosion vias 10 times that
normally expected for cultivated land and 200 times tnat
expected of grassland and 2,000 times that expectod from
forest land.
Eolian sediments are composed of material that was
borne, deposited, produced, or eroded by the wind. Lakes in
evergreen forests are at times so covered with pine pollen
that their surface takes on a golden hue. This material is
eventually deposited as organic sediment. Lakes nearly
industrial plants or construction sites also receive fallout
which may contain lead, mercury, and a host of otner
contaminants.
Thermal Pollution
With the settling of North America vast stands of rorest
canopy and tall prairie grass were removed, exposing the
soil beneath to direct solar radiation. An obvious result
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was a qeneral warming of the continent's streams ana lakes,
Today an urbanized society and an industrial economy, witn
continually rising demands for power plants and factories,
many of which discharge thermal energy, contribute to tae
warming of our waterways.
Effects of Thermal_Pollutign
An increase in ambient water temperature caused by
thermal effluents entering a lake may increase the metabolic
rate of aquatic organisms and cause a corresponding increase
in the food required for inaintenance of body weight with no
growth. Members of the freshwater family of fishes,
o
Centrarchidae, reportedly ate three times as much tooa at 20
C as at 10 C (20), and brown trout, Salmo trutta, snowed a
constantly increasing feeding rate from 10°C to 19°C, above
which the rate declined abruptly. When water temperatures
rise, the swimming speeds of fish may also be affected.
Acclimated goldfish increased their swimming speeds as
temperatures were increased from 5°C to 20°C (21). Cruising
speeds remained fairly constant until temperatures reached
30 C and then dropped off rapidly with further temperature
increases.
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The optimurr temperature for maximum qrowt.h depends on
available food. Young sockeye saliron raised in tan*s witn
surplus food grew best at temperatures near 15°C (22), ana
at higher or lower temperatures their growth rates ueclined
sharply. However, when given a small daily food ration
these fish grew best at near 5°C and did not grow at *11 at
15°C. Increasing the temperature of a relatively barren
water body, resulting in increased food requirements or trie
fish populations, could conceivable lower the fish
supporting capacity of the lake or impoundment.
Increased water temperature reduces the solubility of
oxygen thus reducing the dissolved oxygen available to
aquatic fauna. This harmful effect is intensified because
the oxygen consumption of aquatic vertebrates is
approximately doubled for every ten degrees* C rise in
temperature (23).
Fishes will adapt to higher temperatures, but the
success of this process depends en the absolute temperature,
the length of exposure to high teirperature and the rate ot
temperature change. Gradually exposing fishes to higher and
higher temperatures acclimates them to these elevated
temperatures, but it lessens their ability to survive at low
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temperatures (2<*) . It follows that the thermal shock causeu
by a large reduction in thermal effluent, ciurir.q a power
generating station's shutdown, could be more damaging to
aquatic biota than the original water temperature increase.
Meyer (25) points out that subtropical fishes are living
much closer to their thermal limit than are polar species.
Thus thermal pollution may be more critical in soutuern
states than in northern states-
Elevated water temperatures may stimulate the activity
of parasites and disease. Hedgpeth and Gonar (26) noteu
that maintaining bivalves in warm waters had the
disadvantage of increasing the predatory gastropoa activity,
since oyster and mussel pests such as £rosa^£inx ana inais
thrive at warmer temperatures.
Many biological cycles are initiated 1-y a temperature
stimulus. Such an impulse induces sexual activity in marine
animals (27). Salmon do not spawn it the water temperature
is too high. The ability of a species to adapt- to an
incremental temperature rise may fce different at various
ontogenic stages. For example, fish egos and larvae may
have more sensitive temperature requirements than the
adults. Trout eggs do not hatch if they are incuoatea in
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water that is too warm. and some fish species require a
winter chill period tor successful reproduction. In the
vicinity of a thermal outfall fish might hatch too early in
the sprinq before their natural food has become plentitul.
Insect nymphs in an artificially warmed water body mignt
emerge too early for mating flight and be immobilized by tne
cold air.
Sublethal temperature effects are also important. For
example, the embryos of brown trout reared at high
temperatures (13°C) yielded significantly smaller embryos
than those hatched at- 2.8°C (28, 29), A larger proportion
of the yolk is required tcr metabolism of embryonic tissues
at the higher temperature.
Temperature increases within the ranges tolerateu by the
existing species tend to increase productivity, provided
t.hat light and nutrients are not limiting. In nortnern
lakes added heat might make the water more attractive for
swimmers, but if this also resulted in extensive growtxi of
filamentous algae or other types of noxious vegetation tiie
advantage may be offset. Increased algal productiviry may
also reduce the ability of predatory fish to see their prey.
When temperature ranges of existing populations are
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exceeded, the species composition will change. Below JO°C
diatoms are often represented by the largest members of
species (30) with green algae becoming more abundant at
temperatures from 30 C to 35 C. Above 35°C blue-green alyae
freguently dominate the flora.
If a thermal discharge tlows out over the surrace of the
lake, it will reinforce any tendency of the lake to stratify
into density layers. Such stratification inhibits mixing
between the surface waters, which are generally rich in
dissolved oxygen, and the hypolimnetic waters, whicn may
become oxygon depleted if not replenished.
Artificially induced temperature changes may trigger the
spawning migration at the wrong time of year. Migrating
fishes must be able to avoid zones of unfavorable
temperature, as such zones may block the migration, and
spawning may be thwarted.
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Sources of Thermal Pollution
Power generating plants are the prime source or thermal
pollution. This trend may continue since, in the Uriitea
States, power generation has doubled every ten years since
19U5, and indications are that future requirements will
demand an even higher rate of increase. Other sources of
thermal pollution are industrial effluents, sewaue
effluents, and exothermic reaction associated witn oxidation
of organic matter.
Selected Toxic Substances
Historically, natural weathering of mineral rich roc*
formations was the primary mechanism for release ot toxic
substances to the aquatic environment. During the past
decades the man-induced release of naturally occurring toxic
materials combined with the discharge of synthetic toxic
compounds has far exceeded the injut through natural
weathering. As a consequence of the increased ratt ot
input, low level residues of toxic substances are touna
throughout the total biosphere.
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Pesticides
The most widely dispersed of all man-made toxic
materials in the environment are the pesticides, Inciuaed
in this rather heterogeneous group of compounds are ayents
designed to eliminate or control a variety of nuisance
organisms. Many of the compounds are toxic or potentially
toxic to most life forms while others are specific in their
killing. Both inorganic and organic compounds are used.
Increased and frequently indiscriminate use of
pesticides during the past 20 to 30 years has resulted in an
ubiquitous low level residue of certain classes of these
compounds in the total biosphere. Release of these agents
to the environment comes about not only as a consequence of
agricultural activity but also from manufacturing processes,
accidental spills, and disposal of containers and unused or
outdated agents.
In the United States approximately 900 chemicals are
formulated into over 60,000 pesticidal preparations whicn
include the insecticides, fungicides, herbicides and plant
growth regulators <31). The majority of the pesticides in
use today are synthetic organic compounds, however.
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inorganic pesticides and plant extracts are still used. The
inorganic pesticides include such compounds as lead
arsenate, calcium arsenate, copper sulfate, mercuric
chloride and Paris Green. The advent of the more etrective
organic pesticides has caused a decline in the use ot tae
inorganic pesticides.
Certain botanicals or plant extracts such as pyrethrum
and rotenone are still in demand, as they are relatively
safe to handle, are quite specific in their killing, and do
not persist very long in the environment. These pesticides
are widely used around livestock as they are relatively non-
toxic to mammals (31).
The synthetic organic pesticides include the familiar
chlorinated hydrocarbons or organochlorines such as DDT,
dieldrin, chlordane and toxaphene. Also included are the
organic phosphates (malathion, parathion, etc.), and tne
carbamate insecticides such as carfcaryl (Sevin) and several
fungicides, herbicides and defoliants.
In 1967 the United States production of all pesticides
totaled 476.3 x 10^ kg (31). Between the years 1964 and
1968 total pestici-de production increased at the rate ot 9
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206
percent per year. However, recent data indicate tnat tnis
trend has reversed, as total sales of synthetic organic
pesticides were down 6.9 percent in 1971 from th^ 19c'J total
(32). Present trends suqgest that the pesticide; industry
may he on a three-year plateau, after which s^les are
expected to increase at an unknown ratr (32). The domestic
use of DDT and other persistent pesticides has beeu
declininq in recent years, reflecting a shift to the ust of
the less persistent chlorinated hydrocarbons and organic
phosphates. Between the years 1956 to 1970 domestic
supplies of the chlorinated hydrocarbons dropped crom nearly
110.8 million kq (2UU million Ibs) to about 14 million Kg
(31 million Ibs). Conversely, during the same period,
production of the orqanophosphates increased from J.2
million kg (7 million Ibs) to 25.9 million kq (57,000,000
Ibs) (33). Recently the Administrator of the United States
Environmental Protection Agency issued an order restricting
the use of DDT primarily to Public Health Officials and
physicians for the control of disease vectors, lice and ror
health quarantine purposes (34). This order, which oecame
effective on January 1, 1973r may result in substantially
increased use of other insecticides for insect control.
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The major pathways of pesticides into the fresh water
environment are through direct application on surrace waters
and from surface runoff (31). Industrial and domestic
sewage, and fallout from atmospheric drift and precipitation
also contribute to the contamination of waterways by
pesticides.
Upon reaching a stream, downstream transport of
pesticides occurs through movement of the solubilized
fraction and residues sorbed onto suspended or saltated
particles. As a result of downstream transport, pesticide
concentrations in upstream reaches tend to diminish rapidly,
while levels in the downstream reaches and in receiving
lakes and reservoirs may be increased substantially.
Sediments of lakes and reservoirs, particularly those in
eutrophic water bodies rich in organics, have a hign
affinity for pesticides, and act as sinks or pools for tne
residues. Consequently, pesticides may be removed from tne
water and incorporated into the bottom sediments tairly
rapidly. If siltation rates are high, pesticides in lake
sediments may be effectively isolated from the overlying
waters and removed from involvement in the food web. On tne
other hand in lakes with lower siltation rates, sedimented
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pesticides may be taken up by the benthie biota, which is in
turn consumed by fish and ether predators and thus the
pesticides are reintroduced into the food web. Pesticide
entrapment in lake sediments may be only temporary and
persist only during the period in which the lake is
thermally stratified. Once turnover occurs, if mixing is
complete, the pesticides may be released from the sediments
and redistributed throughout the water.
The recovery rates of lakes treated with pesticides were
studied in Oregon, where two mountain lakes were treated
with the organochlorine, Toxaphene (35). One lake was deep
and biologically unproductive and the other shallow and rich
in aquatic life. The shallow lake recovered rapidly and
trout were restocked within one year. Restocking ot trout
in the deep lake, however, was delayed for 6 years due to
toxic levels of Toxaphene in the water. The reasons given
tor the slower recovery ot the deep lake were thermal
stratification, slower flow through time and reduced
biological activity (35).
All organic pesticides are subject to degradation, with
most pesticides, depending upon environmental conditions,
degradation may be complete in a few days to a few months.
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209
The orqanophosphates, for example, are readily hyarolizea in
alkaline water at high temperatures, however, a*- reaucea &U
and temperatures they persist for several months (Jb). ine
non-persistent pesticides, as with the organophos^hates,
although acutely toxic, do not pose long term hazarus to
aquatic life and apparently are not accumulated throuyn the
food chain. The organochlorine compounds, however, arc-
highly resistent to degradation, or the degradation proaucts
may be persistent. These compounds may be accumulatea by
the biota directly from the water (37) or through trie rood
chain, resulting in concentrations in the tissues oi higher
trophic level animals that iray be several thousand times
that found in the ambient waters.
That persistent pesticides are rapidly removed rrom tne
water and concentrated in the sediments and biota was
demonstrated by Bridges gt al (38) who described tne
dispersion and persistence of DDT in a farm pond.
Sufficient quantities of DDT were applied to a pona to yiela
a 0.02 mg/1 concentration in the pond water. The
distribution of DDT in the water, sediments and biota was
observed for about 18 months. DDT had disappeared from the
water after 3 weeks. Maximum concentrations in tne
sediments of 8.30 mg/kg were recorded one day after
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treatment, but had declined nearly to pre- treatment levels
after 8 weeks. Vegetation samples revealed maximum
concentrations of 30.7 mg/kg one-half hour after treatment,
and after eight weeks contained 5. 1 mg/kg. DDT
concentrations in the new vegetation crop, one year alter
application corresponded to post treatment levels.
Accumulation in fish of DDT and its metabolites reacned 3 to
U mg/kg within 1 month after treatment, concentrations in
excess of 2 mg/kg were still present in fish when the study
was terminated.
High level pesticide residues in lakes have posed
problems in recent years by interfering with the
reproductive patterns of fish or rendering them unfit for
consumption due to excessive contamination. Concentrations
of DDT exceeding 4.75 mg/kg in the eggs of lake trout
resulted in up to 100 percent mortality in developing try in
New York lakes whose watersheds had been treated witn DDT
for gypsy moth control (39).
In Lake Michigan similar mortalities of coho salmon
were attributed to DDT, dieldrin and PBC concentrations in
the eggs (31). Reinert (41) found DDT and dieldrin in
fishes from all the Great Lakes, concentrations in Lake
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211
Michigan fishes were found to be 2 to 7 times as nigh as
those in tish from the other Great Lakes. Samples rrom
canned coho salmon had DDT and dieldrin concentrations of
7.10 and 0.09 mq/kg respectively. Concentrations in adult
salmon caught just prior to spawning exceeded 12 ing/kg JDT
and 0.1U mg/kq dieldrin. Levels in excess of those
established by the FDA have resulted in Lake Michigan coho,
and several other species, being removed from the interstate
market.
The behavior of pesticides in lake sediments ana tneir
availability for recycling back into the biota are not tuily
understood. Studies on the rates of interchange across muu-
water interfaces and between the vater and the biota are
needed before the magnitude of the problem of pesticide
pollution in lakes can be thoroughly assessed.
Mercury
The problems of mercury contamination in Unitea States
waterways were drawn to public attention in April 1970, wrieii
Canadian investigators reported mercury pollution in Lake
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212
St. Clair and other boundary waters (42). Subsequent
investigations by the United States Federal Water Duality
Administration (now the Environmental Protection Agency)
revealed that the mercury pollution problem was not limited
to the Great Lakes area, but was of national scope (42).
Mercury is a particularly hazardous contaminant in
aquatic systems, owing to its tendency to be transformed
from a relatively immobile inorganic metal to a highly toxic
organic form by the biological process of methylation. Tne
methylation process is accomplished by certain aquatic
bacteria living in the bottom muds (43) , and all inorganic
mercury introduced for aquatic systems is potentially
subject to bacterial methylation, and subsequent uptake by
the biota. Aquatic organisms are able to concentrate
methylmercury directly from the water or through the tood
chain (42 - 47). In general mercury in fish food organisms
increases at each trophic level of the food chain (48) . A
concentration factor of 5,000 or more from water to fi*e rids
been reported (49) and methylmercury magnification in brook
trout has been shown to exceed 10,000 after long term
exposure (50). Such factors as the metabolic rate, food
selection and the epithelial surface area of the individual
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213
fish have been implicated as parameters which affect the
rate at which mercury is concentrated by fish (W, 51).
The toxicity ot mercury compounds to aquatic organisms
has been summarized by various investigators with widely
differing results. It is established, however, that the
toxic level of mercury is affected by several aspects ot
water quality including termperature, pH, organic pollution
loading, hardness, alkalinity, heavy metal loadings ana
dissolved oxygen (50).
In respect to toxicity in natural waters, it is
methylmercury which is of primary concern. Experiments at
the National Water Quality Laboratory indicate that 0.2 mg/1
methylmercury will kill fathead minnows within 6 to 6 weeks
(50) . Toxicity data from the same laboratory on
invertebrates, Gammarus and Daphnia. a top minnow and a
brook trout is said to indicate than none are more sensitive
that the fathead minnow (50) .
Plankton is particularly sensitive to mercury poisoning.
Exposure of phytoplankton to concentrations of 0.1 ug/1 of
methylmercury compounds caused a significant reduction in
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214
photosynthesis, and at levels of 0-50 ug/1 photosynthesis
was stopped (52).
Sources of mercury release to the environment include
natural weathering, burning of fossil fuels, mining,
farming, industrial operations, hospitals, laboratories and
a host of others. Sources of mercury input to the
environment, both man made and natural, are summarized by
Lambou (42). The natural weathering process is said to
release a maximum of 230 metric tons of mercury to the
environment yearly, whereas the amount released by burning
coal is on the order of 3,000 tons annually, and anotner
3,000 tons are emitted as industrial wastes (53).
Mercury pollution in the nation's lakes and rivers poses
a serious public health threat and has restricted sports
fishing and commercial fisheries operations in many areas.
Table VIII summarizes data compiled by the United States
Geological Survey on concentrations of total mercury found
in many U. S. lakes and rivers. Concentrations of total
mercury above the minimum detection limit of 0.5 mg/1 were
found in 140 of the 719 samples analyzed (42).
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215
The problem of mercury pollution in lakes, particularly
the Great Lakes, is of such a magnitude that nany states
imposed fishing restrictions or warnings ot some type
because of high levels of mercury in fish taken from
contaminated lakes. Table IX summarizes State restrictions
which were in effect as of September 1, 1970. Mercury
levels in fish from selected areas of the Great Lakes are
summarized in Table X. These data, based upon composite
homogenized samples collected by the U. S. Fish ana Wildlife
Service (55) reveal relatively low total mercury residue
levels in the upper Great Lakes fishes, with increasing
concentrations in fishes taken in the lower Great l,aKes.
Average residue levels in the Lake Ontario fishes exceeded
the 0.5 mg/kg level for edible portions established by trie
Food and Drug Administration.
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216
TABLE VIII
Summary of total mercury measured in water sables fron U.S.
rivers and lakes obtained during October and November, 1970. I/
State
.5 2/
Number of samples with ug/1
.5-.9 1.0 1.9 2.0-2.9 3.0-3.9 4.0-4.9 5.0-5.9 6.0-C.->
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of Columbia
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
Total
16
8
10
10
6
17
24
3
1
8
17
4
5
13
19
8
-
3
11
6
13
8
15
12
8
9
8
7
3
3
18
15
27
21
5
9
9
13
42
4
16
5
10
27
8
3
11
13
12
15
1?
579
—
—
3
11
2
1
—
-
4
—
2
1
2
2
1
4
3
1
1
—
6
4
1
-
—
-
2
4
1
-
—
6
-
1
8
2
-
1
—
-
1
2
-
2
-
-
-
-
-
-
79
1
1 ^
~
10 3 - 1
_ » ^
"• ™
- ~ ~ "
34 —
1
2_ M •
1
1
™ ™ — —
2
_ • *
4211
1
1 - - ~
• « — -
-
• • —
— — — —
«.«• — —
1 1
2« «
11-
_ - - -
1
1 -
_ - - -
_ — — —
•» •» — —
-
— «. — —
1
7
1
- - - -
w •- — —
— «• — —
_ - - -
_ - - -
-
3
1 •• — —
_
- - - -
1
_
1
i r i _
44 10 3 2
-
__ __
1
—
—
_ _
~
~
_ —
1
~ ~
- —
— —
""
~ ~
~ ~
— —
•"• ""
— —
— —
— —
— —
— —
— ™*
-- —
— —
- -
— —
— —
- -
— —
— —
- -
— —
-
0 2
I/ Summarized fror» Durum et^ al, (1970),
2/ Below detection limit.
Source: (41)
-------
TABLE IX
State fishing restrictions because of mercury — September 1,1970
State
Michigan
Closure of
sport fishery
So. L. Huron, West
L. Erie take no
walleye, drum,
white bass
Wisconsin
Ohio
New York
Vermont
Pennsylvania
Alabama
L. Onondago
Mississippi
North Carolina
Tennessee
Closure of
commercial fishery
Detroit R., L. St.
Clair, St. Clair R.
closed. So. L. Huron,
West L. Erie closed
to walleye, drum,
white bass
L. Erie closed to
walleye
Tombigbee P.. closed
Mobile R., Tensaw R.,
Mobile-Tensaw system,
Tennessee R. and
impoundments, closed
Pickwick L. closed
Pickwick L. closed
Warning or catch and
release for sport fishery
Detroit R., L. St. Clair,
St. Clair R. catch and
release only
Wisconsin R., catch and
release recommended; no
more than 1 meal per week
Lake Erie - warning
released via news
L. Champlain, Erie,
Ontario, Oswego R.,
Niagara R., St. Lawrence
R. danger warnings
L. Champlain, L. Memphre-
magog, danger warning
L. Erie, danger warning
for walleye, drum, small -
mouth bass, white bass
Tombigbee R. up to Jackson
Dam, warning
Mobile R., Tensaw R.,
Mobile-Tensaw system
Tennessee R. and
impoundments, warning
Pickwick L., warning
Danger warning (general)
Pickwick L., warning,
catch and release
Embargo or warning
to commercial fishery
Embargo on species other
than walleye, drum,
white bass
Embargo on white bass
N)
L. Champlain, L.
Memph remagog, emb argo
on sales
Source: (41)
-------
TABLE X
Mercury residues in fish, 1969 and 1970
1970
Average Size
Station Location
Genessee River
Scottsville,
N.Y.
St. Lawrence River
Massena, N.Y.
Ontario
Port Ontario
N.Y.
Lake Erie
Erie, Pa.
Lake Huron
Bay Port,
Mich.
Lake Michigan
Sheboygan,
Lake Superior
Bayfield,
His.
Species
White sucker
Redhorse sucker (R)
Rock bass
Walleye
Northern pike
White sucker
Yellow perch
Yellow perch (R)
Northern pike
Yellow perch
Yellow perch (R)
White perch
Rock bass
White sucker
Freshwater drum
Yellow perch
Yellow perch (R)
Carp
Channel catfish
Yellow perch
Yellow perch (R)
Bloater
Bloater (R)
Yellow perch
Bloater
Lake whitefish
Lake whitefish (R)
Lake trout
No. of
Fish
Length
(cm)
Weight
(kg)
Total
Mercury
(mgAa)
GREAT LAKES DRAINAGE
4
4
4
4
3
5
5
4
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
35.6
33.5
20.6
35.0
43.7
17.8
21.1
52.3
21.6
21.3
21.1
16.5
45.7
35.8
24.6
22.6
49.8
41.1
23.1
9.1
28.4
23.9
27.9
26.1
44.7
46.0
59.4
0.54
0.41
0.23
0.32
0.68
0.09
0.14
0.95
0.18
0.18
0.18
0.09
1.20
0.59
0.18
0.14
1.82
0.64
0.14
0.3
0.27
0.86
0.27
0.14
0.77
0.86
1.82
.15
.19
.39
.17
Avg. .24
.22
.20
.18
.39
Avg. .27
.86
1.00
1.30
.30
Avg. .84
.31
.43
.23
.15
Avg. .31
.07
.07
.08
.05
Avg. .07
.09
.10
.07
Avg. .09
.15
.08
.06
.29
Avg. .17
No. of
Fish
5
5
2
2
1970
Average Size
Lenoth Weight
(cm) (kg)
3
5
5
5
5
5
5
5
5
5
38.4
18.3
43.7
43.7
26.4
24.1
21.8
37.6
34.3
23.9
41."
40.4
25.1
30.5
26.2
28.5
40.9
55.9
0.68
0.14
0.73
0.73
0.27
0.23
0.27
O.f>8
0.50
0.18
0.95
0.68
0.23
0.36
0.27
0.18
0.54
1.36
Total
Mercury
(mgAg)
.13
.22
.25
.25
Avg. .20
.48
.43
.65
Avg. .52
.10
.15
.13
Avg. .13
.05
.13
.09
Avg. .07
.09
.27
Avg. .18
.16
.05
.14
Avg. .10
CO
Source: (41)
-------
219
Polychlorinated Biphenyls (PCB* s)
Recently, evidence has been compiled which indicates
that the PCB's are widely distributed throughout the
environment and that they can have adverse ecological ana
toxicological effects (54).
An Interaqency Governmental Task Force (5U)
investigating the effects of PCB's in the environment
concluded that PCB's present a potential, but not an
imminent, health hazard, except for accidents which result
in high level exposure. They have, however, been tound in
fish and wildlife at levels which may adversely attect
aquatic organisms.
PCB's have been manufactured commercially since 1929.
Historically PCB's in the United States were used in a
variety of applications including plasticizers, hydraulic
fluids and lubricants, surface coatings, inks, adnesives,
pesticide extenders, and microencapsulation of dyes for
carbonless duplicating paper. Beginning in 1971, however,
the Monsanto Company reportedly reduced its production
-------
220
volume, limiting its distribution to industries concerned
with the manufacture of electrical apparatus (54).
The water environment is thought to be the principal
sink and transport mechanism for PCB's, but there are tew
data on the removal, disappearance and sequestering or tne
substance in soils or bottom sediments of rivers, lakes,
estuaries or the ocean (54). Concentrations in fresa water
away from any immediate source of waste discharges contain
less than one ug/1; sediment samples contain up to several
hundred mq/kg near some industrial outfalls.
PCB's are fat soluble and tend to be concentrated at
succeedinqly hiqher levels as they pass through the various
steps of the food chain. They have been shown to accumulate
in fish and aquatic invertebrates to levels of 75,000 times
the ambient water concentration, and to be accumulated rrom
concentrations as low as 0.05 uq/1 (54),
PCB's are lethally toxic to fish and aquatic
invertebrates in concentrations of a few ug/1. Metabolism
and excretion of PCB's by these organisms is very slow (54).
PCB's are only moderately toxic to birds and mammals and
have not resulted in sufficient mortalities to affect
-------
221
populations, although they are thought to have contributed
to direct mortalities of some birds in the field. The
sublethal physiological effects on wild animals appear to be
of greater significance than the lethal toxicity.
Phthalate Esters
Phthalate ester residues have keen discovered in various
segments of the aquatic environment in North America,
occurring principally in water, sediment and aquatic
\
organisms in industrial and populated areas (55) . Pntnalate
esters are widely used as plasticizers particularly in
polyvinyl chloride (PVC) plastics (50). They have aiso been
used as insect repellents and in pesticide formulation to
retard volatilization.
The acute toxicity of phthalate esters appears
relatively significant. However, these compounds may be
detrimental to aquatic organisms at low chronic
14
concentrations. Paphnia maqna. exposed to 10 mg/1 or C
di-n-butyl phthalate showed a magnification of 6000 rold.
Upon transfer of* the organisms tc uncontaminated water.
-------
222
however, approximately 50 percent of the material was
excreted within three days (U9) .
Arsenic
Arsenic compounds in the lake environments pose
potential hazards to aquatic life and wildlife and even to
man. Arsenic enters waterways through various routes
including industrial and municipal waste discharges, mine
drainage, pesticides, lead shot, coal burning and smelting
of ores (55). Many detergents and laundry products contain
arsenic and their discharge in waste effluents contributes
substantially to arsenic contamination ot waterways as most
sewage treatment plants do not remove arsenic (56).
Arsenic was frequently applied to lakes and ponas tor
the control of submerged aquatic vegetation. Jn the period
from 1950 through 1962, over a.54 x 10^ kg (1 million
pounds) of arsenic trioxide were applied to Wisconsin laK.es
for weed control (57), In Minnesota nearly U.31 x 10* kg
(95,000 pounds) of arsenic trioxide were applied tor
submerged aquatic plant control in 1958 (57). Michigan and
-------
223
other states also reported using arsenic trioxide as a weed
control agent, but in unknown quantities.
It is known that arsenic can te biologically
concentrated and magnified in the food web (58) as well as
accumulated in lake bottom muds (59). Some concentration
factors for certain marine organisms were given by Lowman
(58) as follows: Benthic algae, 2000; mollusc muscle, 650;
crustacean muscle, UOO; and fish muscle, 700. Concentration
in bottom samples taken in a treated lake ranged rrom 10 to
82 mg/kg (60), Dupree (59) studied the arsenic content of
the water, soil and biota of lakes which had been treated
wit.h soil arsenite and subsequently drained and retilled ^
to 3 times. The following year after treatment tne sodium
arsenate content of the water ranged up to 0.3 mq/1, in
plankton up to 7.4 mg/kg, and in bottom soil up to O.Jb
mq/kg. These data suggested that arsenic could be released
from bottom muds providing a source to the water aria uiota
for a considerable period after application (59).
The literature on the toxicity of arsenic is rather
confusing. Arsenic is toxic to all animals with a central
nervous system and to most higher plants, but may not be
toxic to lower organisms (56). The toxicity of arsenicals
-------
224
is influenced by the form in which it is accumulated. Tne
organic compounds which may reside in bottom sediments are
less toxic to man than the inorganic compounds, and the
pentavalent compounds (arsenates) are generally much less
toxic than the trivalent arsenicals (arsenites).
Arsenic trioxide, a common aquatic weed control a«jent,
has been found to be harmful to fish food organisms in
concentrations as low as 2.0 mg/1 over an unspecitiea length
of time (56). Conversely, concentrations as high as 17.1
mg/1 have been tolerated by minnows tor one hour with no
harmful effects, and 10.0—20.0 mg/1 were tolerated Dy insect
larvae for an unspecified period of time without apparent
damage (56).
Sodium arsenite applied to experimental ponds in
concentrations of 4 mg/1 substantially reduced the numbers
of bottom organisms and reduced bluegill production. A U
mg/1 application also killed microcrustacea and greatly
reduced the rotifer population (56).
Because the relatively insoluble arsenicals are present
in many waterways, potential hazards tc those forms wnicn
accumulate arsenic, exist. Arsenic builds up slowly in the
-------
225
body and, according to some medical sources, long term
arsenosis may not be detectable for two to six years or more
(56).
Ammonia and Sulfides
Both ammonia and sulfides are potentially toxic
substances which are discharged from a wide variety of
industrial processes as well as municipal sewers.
In unpolluted lakes ammonia and sulfides are usually
present in low concentrations. However, in lakes receiving
decaying organic waste loads or with high natural organic
sediment content, the biological production of ammonia and
hydrogen sulfide in unusually high concentrations may pose
potential toxicity problems.
During the summer stagnation periods the concentration
of free ammonia and hydrogen sulfide in lakes generally
increases with depth. The bottom ooze may contain many
times the concentrations found in the overlying waters. Tne
development of isothermal conditions and subseguent mixing
tends to distribute the dissolved gases throughout the water
-------
226
column. Consequently ammonia and hydrogen sulfide
concentrations in the bottom waters are usually lowest
during the periods of spring and fall overturn.
The toxicity of both ammonia and sulfide is determined
to a large extent by the pH of the water. Gaseous ammonia
is readily soluble in water forming ammonium hydroxide which
dissociates into ammonium and hydroxide ions in a pH
dependent reaction. The toxic component of ammonia solution
is non-ionized ammonia. Since the percentage of non-ionized
ammonia increases with increased pH, the toxicity of the
solution does also (50). Sulfides derive their toxicity
from hydrogen sulfide which is formed by reaction witn tine
hydrogen ion when added to water. Hydrogen sulfide
dissociates in solution yielding the HS and H ions, and
the higher the pH the more complete the dissociation
reaction, therefore at higher pH values toxicity is reduced.
Numerous other factors such as temperature, dissolved oxygen
tensions and free carbon dioxide concentration also
influence the rate of the reactions involving these
substances, hence influencing the toxicity.
Toxicity problems arising frcir excessive concentrations
of ammonia and hydrogen sulfide are more common in streams.
-------
227
particularly those with a heavy industrial or municipal
water loading, than in lakes. The potential tor toxic
problems exists in lakes, however, particularly in tnose
with high organic content in the sediments. In snallow
northern lakes toxic levels of ammonia ir.ay develop under
heavy ice cover, and in combination with low oxygen tensions
contribute to stress conditions fcr aquatic life and in some
cases result in heavy fish mortalities.
Miscellaneous Problems
Non-Toxic Salts
In the northern United States the practice ot applying
salts to streets and roads to control ice accumulations n<*s
become increasingly common. During the past few decades the
amount of salt (mostly sodium chloride) used for ueicing
purposes has increased exponentially, nearly doubling every
five years (61). During the winter of 1969-70 an estimated
7,700,000 metric tons of salt were used for deiciag purposes
(61, 62).
-------
228
Much of the salt used for deicing purposes is carried
off in melt waters and transported to lakes via storm
sewers, qround and surface waters. As a consequence of the
salt influx, the physical and chemical characteristics ot
the lakes may be changed substantially resulting in
significant ecological alterations and impairing tne IdKe's
utility as a resource. Such is the case in Trondequoit Bay,
near Rochester, New York.
p
The 435 km^ Irondequoit Bay drainage basin, with a 1970
population of 206,000 receives approximately 1 percent
(77,000 metric tons) of the deicing salt used in the United
States (61, 62). Irondequoit Bay is connected to Lake
Ontario by a shallow channel, but little exchange of the
deeper bay water with the lake occurs. The surface area ot
2
the Bay is 6.7 km ^ and maximum depth is 23 m (61).
During the winter of 1969-70, approximately 10 metric
tons of salt were stored in the Bay, while 11,000 metric
tons went out the outlet. Approximately one half of the
77,000 metric tons applied to the roads were stored in soil
and ground water, part of which will eventually reach the
Bay (61).
-------
229
The winter influx ct salt resulted in the development of
a vertical density gradient sufficient to prevent the bay
from mixing during the 1970 and 1971 spring seasons. it
also prolonged the period of summer stratification oy aoout
one month in the fall seasons ot 19f9 and 1970 (as compared
to the tall of 1939) (61, 62).
The full ecological consequences of the artificial
disruption of the circulation patterns due to salt influx
are not known. One effect is to prolong the anaerobic
conditions of the bottom waters. In a normal dimectic lake
anoxic bottom waters are replenished with oxygen duriny both
the spring and fall turnover. Due to the lack of a complete
spring mixing period, the hypolimnetic water of Irondequoit
Bay remain anaerobic for about 9 months ot each year.
It is not presently known how many of the Nation1s
northern lakes are similarly affected by salt runoff, as the
problem has received little attention until recent years.
Present trends in uses of deicing salts suggest that txie
potential for serious problems may be developing.
-------
230
radioactive Wastes
The development of the nuclear newer generating plart,
\vith its dependence upon large volures of coo linn water, has
introduced yet another fom of contaminant to the lake
environment - radioactive naterial. As the nurber o^
nuclear generating stations increases, the number of nuclear
fuel reprocessino plants will also increase, sore impacting
on lakes. The parallel development of these facilities will
increase the potential for rad.ionuclide contamination of
freshwater lakes.
Radioactive wastes create a unicue environrontal problem
in the fom of ionizing radiations of varying eneraies, but
the primary consideration is the potential for huran
exposure to these radiations. In this rocrard, radior.uclidos
of concern in the aqueous environment include cerium,
cobalt, iodine, strontium, tritium, and Plutonium.
Consequences of Release of Radioactive Wastes
Uhile many radioactive wastes are of very short half-
life and low energy, others present problems because of
-------
231
their persistence in the aquatic environment (e.g., 129I,
137csj f re con cent rat ion potential in aquatic food chains
leading to man, and subsequent toxicity to man.
Bioconcentration of radioiodine (131I) is of special concern
in this respect since it is readily metabolized and
concentrated in the thyroid, and may become a significant
hazard via the cow-milk-child pathway. In addition to
presenting a potential threat to the biota itself,
bioconcentrated radionuclides could render food sources such
as fish unsafe for human consumption. Significant
quantities of soluble radioactive materials would also
endanger lakes used as municipal water supplies.
Discussions concerning bioconcentration of radionuclides,
and their transfer through aquatic food chains are contained
in respective publications of the Lawrence Livermore
Laboratory (63) and the National Academy of Sciences (64).
The virtual non-removability of radioactive materials in
the aqueous environment coupled with the problem of
radionuclide reconcentration in the biota necessitates
careful control of nuclear facilities which release
radioactive wastes in the vicinity of freshwater lakes.
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232
REFERENCES
1. Anon. 1971. Water use in manufacturing. 1967
census of manufacturing. L. S. Dept. of commerce.
2. Powers, T. J. 1967. National Industrial Waste
Assessment. U.S. Department of Commerce.
3. Parker, F. L. and P. A. Krerikel. 1969. Thermal
pollution: Status of the Art. Vanderbilt University
Nashville, Tenn. Report No. 3.
U. Environmental quality. 1970. First Annual Keport
of the Council on Environmental Quality, pp. 30-39.
5. Anon. 1968. Industrial waste guide on thermal
pollution. Federal Water Pollution Control
Federation, U.S. Department of Interior.
6. Anon. 1970. Clean water for the 197Q»s. Federal
Water Quality Administration, U.S. Department of tne
Interior.
7. Happ, S. C. 1941. Sedimentation in artificial iaK.es.
In: A symposium on hydrotiology. Wisconsin Univ.
Press, Madison, Wis.
8. European Inland Fisheries Advisory Commission.
1965. Working part on water quality criteria
for European freshwater fish. Report on finely
divided solids and inland fisheries. Internat.
J. Air Water Pollution 9:151-168.
9. Duck, H. D. 1956. Effects of turbidity on fisn ana
fishing. Trans. N. Amer. Wildlife Conf. 21:**29-6i.
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233
10. Gumerman, R. C. 1970. Aqueous phosphate ana
sediment interaction. Proceedings 13th Conterence
on Great Lakes Research, part 2. Great Lakes Kesearcu
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