WATER POLLUTION CONTROL RESEARCH SERIES
DAST-26
13040EYX 11/69
Agricultural Practices
and Water Quality
PROCEEDINGS OF A CONFERENCE CONCERNING
THE ROLE OF AGRICULTURE IN CLEAN WATER,
NOVEMBER 1969
*T-S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe
the results and progress in the control and abatement
of pollution of our Nation's Waters. They provide a
central source of information on the research, develop-
ment and demonstration activities of the Federal Water
Pollution Control Administration, Department of the
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Water Pollution Control Research Reports will be
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quests should be sent to the Publications Office,
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AGRICULTURAL PRACTICES
AND
WATER QUALITY
Proceedings of a conference concerning
The Role of Agriculture in Clean Water
held at Iowa State University, November 1969
FEDERAL WATER POLLUTION CONTROL
ADMINISTRATION
DEPARTMENT OF INTERIOR
by
Iowa State University
Ames, Iowa
Grant No. 13040 EYX
November 1970
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AGRICULTURAL PRACTICES AND WATER QUALITY
Ted L. Willrich and George E. Smith, editors
Laws, public interest, and political motivation all point to clean
water as a major national concern. When sources of water pollution
are mentioned, agriculture is often listed as a major contributor.
Existing knowledge does indicate that agricultural operations can
contribute to the deterioration of water quality through the release
of sediments, pesticides, animal manures, fertilizers, and other
sources of inorganic and organic matter into the water.
Streams, lakes , and groundwater that are now polluted must be
cleansed. Future pollution must be prevented. However, prevention
cannot be attained without adequate knov/ledge concerning the causes
and sources of pollution. The opinions of the uninformed that in turn
misinform the public can only retard effective progress to assure an
adequate supply of clean water.
This volume, an outgrowth of a 1969 conference held at Iowa State
University, should prove both informative and useful. The papers by
knowledgeable scientists from many disciplines present and evaluate
the existing body of facts on agriculture's contributions to polluted
water and reveal alternative solutions to providing clean water.
This report was submitted in fulfillment of Grant No. 13040 EYX
between the Federal Water Pollution Control Administration and
Iowa State University.
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LIST OF AUTHORS
MINORU AMEMIYA, Associate Pro-
fessor and Extension Agronomist,
Department of Agronomy, Iowa
State University, Ames, Iowa.
D. E. ARMSTRONG, Assistant Profes-
sor of Water Chemistry, University
of Wisconsin, Madison, Wisconsin.
E. R. BAUMANN, Professor, Depart-
ment of Civil Engineering, Iowa State
University, Ames, Iowa.
HAROLD BERNARD, Chief, Agricul-
tural and Marine Pollution Control,
Office of Research and Development,
FWPCA, Washington, D.C.
C. A. BLACK, Professor, Department
of Agronomy, Iowa State University,
Ames, Iowa.
C. S. BR1TT, Assistant to Director,
Soil and Water Conservation Research
Division, ARS, USDA, Beltsville, Mary-
land.
G. M. BROWNING, Regional Direc-
tor, North Central Agricultural Ex-
periment Station Directors, Iowa
State University, Ames, Iowa.
R. S. CAMPBELL, Professor of Zo-
ology, University of Missouri, Colum-
bia, Missouri.
R. J. DEMINT, Research Chemist, Crops
Research Division, ARS, USDA, Den-
ver, Colorado.
S. L. DIESCH, Associate Professor, De-
partment of Veterinary Microbiology
and Public Health, University of Min-
nesota, St. Paul, Minnesota.
R. H. DOWDY, Research Soil Scien-
tist, SWCRD, ARS, USDA, Morris, Min-
nesota.
W. E. FENSTiR, Assistant Professor
and Extension Specialist in Soils, De-
partment of Soil Science, University
of Minnesota, St. Paul, A^innesota.
P. A. FRANK, Plant Physiologist,
Crops Research Division, ARS, USDA,
Denver, Colorado.
L. R. FREDERICK, Professor, Depart-
ment of Agronomy, Iowa State Uni-
versity, Ames, Iowa.
M. C. GOLDBERG, Research Hydrolo-
gist, U.S. Geological Survey, USDI,
Denver, Colorado.
L. D. HANSON, Associate Professor
and Extension Specialist in Soils, De-
partment of Soil Science, University
of Minnesota, St. Paul, Minnesota.
P. A. DAHM, Professor, Department T. E. HAZEN, Professor, Department
of Zoology and Entomology, Iowa of Agricultural Engineering, Iowa
State University, Ames, Iowa. State University, Ames, Iowa.
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vi / LIST OF AUTHORS
H. G. HE1NEMANN, Director, North W. C. MOLDENHAUER, Research Soil
Centra! Watershed Research Center, Scientist, SWCRD, ARS, USDA, Ames,
SWCRD, ARS, USDA, Columbia, Mis- Iowa.
soun.
N. W. HINES, Professor of Law, Col-
lege of Law, University of Iowa,
Iowa City, Iowa.
J. A. MOORE, Instructor, Department
of Agricultural Engineering, Univer-
sity of Minnesota, St. Paul, Minne-
sota.
R. F. HOLT, Director, North Central H. P. NICHOLSON, Chief, Agricultural
Soil Conservation Research Center, and Industrial Waste Control Pro-
SWCRD, ARS, USDA, Morris, Min- grams, Southeast Water Laboratory,
nesota. FWPCA, USDI, Athens, Georgia.
H. P. JOHNSON, Professor, Depart- R. A OLSON, Professor, Department
ment of Agricultural Engineering, Of Agronomy, University of Ne-
lowa State University, Ames, Iowa. braska, Lincoln, Nebraska.
SHELDON KELMEN, Assistant Profes-
sor, Department of Civil Engineer-
ing, Iowa State University, Ames,
Iowa.
H. E. LE GRAND, Research Hydrolo-
gist. Water Resources Division, U.S.
Geological Survey, USDI, Raleigh,
North Carolina.
R. I. LIPPER, Professor, Department
of Agricultural Engineering, Kansas
State University, Manhattan, Kansas.
T. M. MC CALLA, Microbiologist,
USDA, Lincoln, Nebraska.
R. E. MC KINNEY, Professor, Depart-
ment of Civil Engineering, University
of Kansas, Lawrence, Kansas.
W. P. MARTIN, Professor and Head,
Department of Soil Science, Univer-
sity of Minnesota, St. Paul, Minne-
sota.
G. L. PALMER, Instructor, Department
of Agronomy, Iowa State University,
Ames, Iowa.
J. T. PESEK, Professor and Head, De-
partment of Agronomy, Iowa State
University, Ames, Iowa.
D. C. PETERS, Professor, Department
of Zoology and Entomology, Iowa
State University, Ames, Iowa.
H. B. PETTY, Professor and Extension
Entomologist, University of Illinois,
Urbana, Illinois.
J. M. RADEMACHER, Regional Direc-
tor, Missouri Basin Region, FWPCA,
USDI, Kansas City, Missouri.
G. A. ROLICH, Director, Water Re-
sources Center, and Professor, Sani-
tary Engineering, University of Wis-
consin, Madison, Wisconsin.
J. R. MINER, Assistant Professor, De- F. J. STEVENSON, Professor, Soil
partment of Agricultural Engineering, Chemistry, Department of Agronomy,
Iowa State University, Ames, Iowa. University of Illinois, Urbana, Illinois.
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LIST OF AUTHORS / vii
D. R. TIMMONS, Research Soil Scien-
tist, SWCRD, ARS, USDA, Morris, Min-
nesota.
f. I. TIMMONS, Research Agronomist,
Crops Research Division, ARS, USDA,
Laramie, Wyoming.
J. F. TIMMONS, Professor, Depart-
ment of Economics, Iowa State Uni-
versity, Ames, Iowa.
JACOB VERDUIN, Professor, Depart-
ment of Botany, Southern Illinois Uni-
versity, Carbondale, Illinois.
C. H. WADLEIGH, Director, Soil and
Water Conservation Research Divi-
sion, ARS, USDA, Beltsville, Mary-
land.
G. H. WAGNER, Associate Professor,
Department of Agronomy, University
of Missouri, Columbia, Missouri.
J. R. WH1TLEY, Supervisor, Water
Quality Investigations, Missouri De-
partment of Conservation, Columbia,
AAissouri.
T. L. WILLRICH, Professor, Department
of Agricultural Engineering, and Ex-
tension Agricultural Engineer, Iowa
State University, Ames, Iowa.
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TABLE OF CONTENTS.
Foreword xiii
Preface xv
Introduction: Issues in Food Production and Clean Water - - . xix
Cecil H. Wadleigh and Clarence S. Britt
PART 1 / SEDIMENT AS A WATER POLLUTANT
1. Pollution by Sediment: Sources and the Detachment and
Transport Processes 3
H. P. Johnson and IF. C. Moldcnhauer
2. Chemistry of Sediment in Water 21
R. F. Holt, R. H. Dowdy, and D. R. Timmons
3. Land and Water Management for Minimizing Sediment . . 35
Alinoru Amemiya
-1. Workshop Session 16
G. M. Browning, Leader; H. G. Hcinemann, Reporter
PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
5. Significance of Phosphorus in Water Supplies 63
i Jacob Verduin '
I 6. Behavior of Soil and Fertilizer Phosphorus in Relation to
I Water Pollution 72
C. A. Black
1. Sources of Nitrogen in Water Supplies 94
Mai~'in C. Goldberg
8. Chemistry of Nitrogen in Soils 125
F. J. Stevenson and G. H. Wagner ,.,_
• ; 9. Fertilizer Management for Pollution Control H2
(F. P. Martin, IV. E. Fenster, and L. D. Hanson
10. Workshop Session 159
J. T. Pesek, Leader; R. A. Olson, Reporter
PART 3 / PESTICIDES AS WATER POLLUTANTS
11. Chemistry and Metabolism of Insecticides 167
Paul A. Da/im
12. The Pesticide Burden in Water and Its Significance . . .183
H. Page Xicholson
ix
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x / TABLE OF CONTENTS
13. Herbicide Residues in Agricultural Water from Control of
Aquatic and Bank Weeds 194
F. L. Timmons, P. A. Frank, and R. J. Demint
14. Pesticides and Pest Management for Maximum Production
and Minimum Pollution 209
Don C. Peters
15. Workshop Session 224
Don C. Peters, Leader; H. B. Petty, Reporter
PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
16. Livestock Operations and Field-Spread Manure as
Sources of Pollutants 231
J. R. Miner and T. L. Willrich
17. Manure Decomposition and Fate of Breakdown
Products in Soil 241
T. M. McCalla, L. R. Frederick, and G. L. Palmer
18. Manure Transformations and Fate of Decomposition
Products in Water 256
Ross E. McKinney
19. Disease Transmission of Water-Borne Organisms of
Animal Origin 265
Stanley L. Diesch
20. Animal Waste Management to Minimize Pollution . . . 286
/. A. Moore
21. Workshop Session 298
T. E. Hazcn, Leader; R. I. Lipper, Reporter
PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
22. Movement of Agricultural Pollutants with Groundwater . . 303
Harry E. LeGrand
23. Effects of Agricultural Pollution on Eutrophication . . . 314
D. E. Armstrong and G. A. Rohlich
24. Effects of Agricultural Pollutants on Recreational Uses
of Surface Waters 331
Robert S. Campbell and James R. Whitley
25. Effects of Surface Runoff on the Feasibility of Municipal
Advanced Waste Treatment 344
E. Robert Baumann and Sheldon Kelman
PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
26. Legal Aspects 365
N. William Hines
27. Economic Aspects 377
John F. Timmons
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TABLE OF CONTENTS / xi
28. Alliance for Action 390
John M. Radcmacher
29. Accomplishments and Goals 397
Harold Bernard
Index 409
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FOREWORD.
TH
I HE Water Resources Research Act of 1964 (Public Law 88-
379, as amended by 89-404) provided for the investigations of water
problems through organizations at the land-grant universities. In
the midcontinent area, which produces the major portion of the na-
tion's grain and meat, a substantial portion of the research con-
ducted by these organizations has been concerned with pollutants
that could originate from farmland.
At a regional meeting of the organization directors and research
workers from state universities in April 1968, "Pollution of Water by
Agriculture" was the subject for discussion. It proved to be a topic
of intense and widespread interest. It was apparent that the subject
was so broad and complex that well-trained specialists in specific re-
search fields were not communicating with their research associates
in other departments.
This group agreed that there would be an increasing interest
in water quality in the Midwest, particularly in those areas where
agricultural production is a major portion of the economy, and where
crop and livestock enterprises might prove to be important and
growing sources of pollution. It was decided that there was need for
an exchange of ideas and an understanding of basic chemical and
biological processes by those most knowledgeable in specific fields
relating to agriculture as a source of water pollutants. It was
further agreed that only fundamentals and established research facts
(not opinions) should be considered and presented at a level that
could be understood by representatives from other disciplines.
A committee consisting of Professors Don Kirkham, Robert L.
Smith, and George E. Smith was appointed to arrange a regional
conference on "Agriculture and Clean Water." Subsequently a con-
ference was held on the Iowa State University campus November
18-20, 1969. Dr. T. L. Willrich of Iowa State University and Dr.
George E. Smith of the University of Missouri served as cochairmen
of the conference. Professor R. L. Smith (University of Kansas),
Doctors Don Kirkham, Lee Kolmer, E. R. Duncan, H. P. Johnson,
E. R. Baumann, J. R. Miner, and -D. C. Peters (all of Iowa State
University) assisted with the initial planning. In addition to spon-
sorship by Mid-Continent State Research Organizations and Iowa
State University, the Federal Water Pollution Control Administra-
tion also cooperated. The conference was also funded in part by
Iowa Community Services under Title I of the Higher Education Act
of 1965.
Xill
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xiv / FOREWORD
The participants in the conference were some of the most out-
standing research workers in their respective fields. The conference
was attended by about 250 individuals from 32 states. Many disci-
plines, including engineers; agricultural, biological and social sci-
entists; geologists; hydrologists; and specialists (including legisla-
tive representatives) from other fields, attended.
The planning committee was pleased with the interest, the
scientific soundness of the presentations, and the participation. The
conference accomplished the original objectives of the water re-
sources research directors. The information published in this pro-
ceedings is probably the most factual material in one volume on the
chemical and biological reactions in soils and on crop and livestock
production as they may be potential contributors to the degradation
of water quality. This proceedings provides valuable information
to those persons genuinely interested in the relation of modern agri-
cultural technology to the water environment.
DON KIRKHAM, Director
Water Resources Research Institute
Iowa State University
Ames, Iowa
G. E. SMITH, Director
Water Resources Research Center
University of Missouri
Columbia, Missouri
R. L. SMITH, Chairman
Department of Civil Engineering
University of Kansas
Lawrence, Kansas
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PREFACE
• NVIRONMENTAL pollution is a major concern to many people.
When sources of water pollution are enumerated, agriculture is,
with increasing frequency, listed as a major contributor.
Except for chemical pesticides, many materials now designated
as water pollutants, such as sediments, nitrates, phosphates, and
organic materials, have entered streams and lakes since the first
sod was plowed, and even prior to that time. However, the concen-
tration of these pollutants in water has generally increased with
time. A portion is from agricultural lands. The remainder is from
nonagricultural operations.
Movement of pollutants into water is controllable if it results
from man's activities. However, water quality degradation by natural
causes also occurs, and this may not be controllable.
As the nation makes an effort to correct abuses to its water
resources, there is a need to determine the causes of water quality
degradation and to quantify pollution contributions from the many
sources.
Until such time as adequate facts are made available through
research to delineate causes and sources, conflicting opinions will
continue to flourish and programs to control and abate pollution
will be less effective and efficient in the use of limited resources.
Existing knowledge indicates that agricultural operations can
contribute to water quality deterioration through the release of
several materials into water: sediments, pesticides, animal manures.
fertilizers, and other sources of inorganic and organic matter.
Sediment from land erosion can be a pollutional material in
surface water. Although soil loss from cultivated land is the major
source of sediment in streams and reservoirs in most areas, highway
construction, rural roads, stream bank erosion, gully erosion, housing
developments, strip mines, and logging operations are also important
contributing sources to production of sediments. Sediment reduces
the storage capacity of reservoirs and lowers their value for recrea-
tional uses. Sediment, depending on origin, contains different inor-
ganic minerals and organic compounds. Both supply plant nutrients.
These nutrients can stimulate the growth of undesirable aquatic
plants that on decomposition can cause eutrophication and increase
costs when surface water is treated for domestic use or for industry.
Decomposition of the organic material can utilize dissolved oxygen
in water. Residues of slowly degradable pesticides used in agricul-
XV
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xvi / PREFACE
tural production are adsorbed on sediments. These may serve as a
reservoir to be taken up by aquatic plants and eventually enter the
food chain.
Production economics and a shortage of farm labor have caused
some livestock and poultry operations to develop as an agribusiness
with large numbers of animals concentrated on small land tracts.
Concentrated animal wastes have created problems of waste dis-
posal and water pollution through runoff and leaching. Animal
manures for soil fertility maintenance are no longer considered as
valuable as they once were. Nutrients required in crop production
can frequently be applied in chemical fertilizers at a lower cost than
the cost of hauling and spreading animal wastes. However, land
application of animal manures continues to be the least-cost disposal
alternative in most situations and the preferred method to reuse the
plant nutrients they contain. Lot runoff has less nutritive value than
concentrated manure, but the plant nutrients and organic matter
that it contains can pollute a receiving body of water. Consequently,
many states have or are in the process of regulating feedlot runoff
discharges to prevent water quality degradation.
The use of chemical fertilizers, with other practices, has pro-
vided ample crops for domestic consumption and export to meet the
needs of an exploding world population. At least one-third of this
nation's food production can be attributed to the use of chemical
fertilizers. Therefore, fertilizer use is essential to prevent mass
starvation. However, a portion of the applied fertilizer may be re-
moved from the soil by leaching or runoff and thus enter a ground-
water or surface-water body along with plant nutrients from other
sources. Inadequate data are available to separate nutrient contribu-
tions from the many sources: chemical fertilizers; weathering of
soil minerals; mineralization of nature's storehouse of humus; crop
residues; animal manures; atmospheric contributions of nitrogen
through rainfall, soil adsorption, and legume fixation; and many
domestic, municipal, and industrial wastes.
The problem of pesticides as pollutants is complex. The use
of these compounds, combined with other management practices, has
permitted the production of an abundance of a wide variety of foods.
However, some of the more effective pesticides degrade only slowly.
Some may dissolve in water or be sorbed on sediments. The more
resistant materials may accumulate and enter the food chain. Given
a choice, few consumers would buy foods which contain insects,
are affected by disease, or are contaminated by rodents—no matter
how low the price. It is doubtful if sufficient food could be grown,
stored, and processed that would meet the requirements of the Food
and Drug Administration without the use of pesticides. There is,
however, a need to develop effective new compounds that do not
persist in soil, water, or plant or animal tissue.
Laws, public interest, and political motivation point to clean
water as a major national issue in coming years. Streams, lakes, and
groundwater that are polluted must be cleansed. Future pollution
must be prevented. However, prevention cannot be attained without
adequate knowledge concerning the causes and sources of pollution.
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PREFACE / xvii
The opinions of the uninformed that misinform the public can only
retard effective progress to assure an adequate supply of clean water.
The materials contained in this volume should he both informa-
tive and useful. It was assembled by knowledgeable scientists, rep-
resenting many disciplines, to identify the role of agriculture in clean
water; more specifically, to present and evaluate the existing body
of facts as they identify agriculture's contributions to polluted water
and reveal alternative solutions to provide clean water.
TED L. WILLRICH
Extension Agricultural Engineer
Iowa State University
Ames, Iowa
GEORGE E. SMITH, Director
Water Resources Research Center
University of Missouri
Columbia. Missouri
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INTRODUCTION.
ISSUES IN FOOD PRODUCTION
AND CLEAN WATER
CECIL H. WADIE1GH and CLARENCE S. BR1TT
E AMERICANS are carnivorous.
The average person's dinner plate accounts for 238 pounds of
flesh per year. Three-fourths of this consumption is of red meat, and
nearly half of the total is beef. Poultry now provide one-fifth of our
total meat consumed, while lamb and fish account for a rather small
percentage of the total.
We are eating just twice as much beef per capita today as we
were 30 years ago. In fact, if a visitor from outer space were to enter
one of our wonderful restaurants, he would gain the impression that
the favorite indoor sport of Americans is that of attacking a juicy
steak.
I am delighted to be an American!
Our inventory of beef cattle has been increasing at about twice
the rate of our population. Since our numbers of dairy cattle have
been decreasing rather markedly during the past 20 years, total cattle
population appears to be leveling off at about 110 million.
A big Holstein cow will produce 75 pounds of fecal wastes a
day, along with 20 to 30 pounds of liquid wastes. A little effort with
a slide rule will tell you that a 100-head dairy produces 1,800 tons of
wastes a year, exclusive of bedding. Obviously, every dairyman has
no small problem in working out a system of materials handling.
Beef steers out on the range may produce only 30 pounds of
fecal wastes a day, and 15 to 20 pounds of liquids. Cattle being fat-
tened in feedlots daily produce between 35 and 60 pounds of fecal
wastes and between 18 and 25 pounds of liquids.
The poultry industry also faces major problems in waste dis-
posal. Per capita consumption of fryers has increased 26-fold in the
last 30 years. Furthermore, in terms of 1968 dollars, the farm price
per pound of broilers is only one-fourth of what it was 30 years ago.
How could one have a more vivid picture of what improved agricul-
tural technology means to the food consumer?
CECIL H. WADLEIGH is Director of the Soil and Water Conservation
Research Division, ARS, USDA. CLARENCE S. BRITT is Assistant to
Director of the Soil and Water Conservation Research Division, ARS,
USDA.
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xx / INTRODUCTION
Now let us consider a few of the problems that have developed
because of increased production of animal wastes and the demands
of a burgeoning population in suburbia that voices loud concern
about the quality of its environment, with special emphasis on air and
water.
Many of these suburbanites have emigrated into the rural fringe
in order to live in the pastoral delights of a rural atmosphere—and
then have vigorously complained about some of the rural atmosphere
they have received. Many of them have problems in water supply
and waste disposal.
We can now recognize that our current animal waste disposal
problems were markedly affected by two developments that took
place in 1912. We can assume beyond all reasonable doubt that the
distinguished German chemist, Fritz Haber, had no idea that he was
sowing the seeds of a massive manure disposal problem in the United
States when in 1912 he succeeded in synthesizing ammonia by pass-
ing H2 and N2 over hot iron filings at high temperature and pressure.
The seeds were not long in sprouting. Haber's process, with the de-
velopmental work of Karl Bosch, was a tremendous contribution to
Germany's armed might during World War I by making Germany in-
dependent of Chilean nitrate (Taylor, 1953).
This synthesis of ammonia was first performed in the United
States in 1920 at the Fixed Nitrogen Laboratory set up by the War
Department in 1919. By the late 1920s, synthetic ammonia for
fertilizer use was in commercial production. Figure A shows that
during the past 50 years, use of fertilizer nitrogen has doubled about
every 10 years until in 1969 we used nearly 7 million tons. This
increase in usage has been abetted by the relatively low cost of nitro-
gen. For example, during this past year many a ton of nitrogen was
applied to fields at a cost of less than 5 cents a pound.
70OO -
FIG. A. Use of plant nu-
trients, 1920 to 1968.
1920
1930 I94O
1950 I960
YEARS
1970
1980
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INTRODUCTION / xxi
- 200
FIG. B. Acreage of 59
principal crops harvested,
plus acreages in fruits,
tree nuts, and farm gar-
dens. Total United States
population, including per-
sons in our military forces
in this country and
abroad.
1920 1910 I94O 1950 I960 1970 1980 IDSO 2000
YEAR
This rapid increase in the use of chemical nitrogen, along with
other purchased inputs, is closely associated with the fact that al-
though the United States has had a sharp increase in population,
there was a marked decline in acreage of cropland harvested as
shown in Figure B. The rapid increases in use of weed killers and
farm machinery are other inputs that have contributed to this tre-
mendous increase in efficiency of land use to meet our population
growth. Our corn crop, which is a primary source of feed in animal
production, provides an example of the effect of enhanced farm
technology on land requirements in producing an abundance of
animal feed at low cost.
During the past 20-odd years, the corn acreage harvested has
decreased markedly, so it is only about two-thirds of what it was in
1945. Nevertheless, our corn production over this period has in-
creased very significantly, to double the total bushels produced in
1940. These trends took place because of the rapid increase of aver-
age corn yield per acre since 1940 due to the increased use of fertil-
izer and other purchased inputs upon corn land. As a consequence
the price of corn to the farmer in 1968 dollars has shown a very
significant general decline since 1940, which, in turn, has its impli-
cations on the price of the tremendous amount of meat we eat. The
corn crop has received a high degree of sophisticated mechanization,
including eight-row planters that sow seed, distribute fertilizer, and
apply pesticides all in one fell swoop.
This rapid increase in field mechanization reminds us of another
very significant event that took place prior to World War I that now
has a very marked bearing on our animal waste disposal problems.
During 1912-14, Henry Ford started mass production methods, in-
cluding continuously moving assembly lines. This immediately made
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xxii / INTRODUCTION
possible the assembling of a Model-T in 93 minutes. This innovation
in materials handling sparked the American industrial revolution.
The value of man's labor was greatly increased. With the adoption
of electronic controls to assembly-line methods, industry made further
advances in efficiency of production. With the advent of World War
II, farm labor became in short supply. Innovative poultrymen and
cattle feeders began installing labor-saving devices involving auto-
mated silos, conveyor belts, mixers, and all manner of schemes to
expedite the handling of feed. Thus one man became able to feed
thousands of cattle and tens of thousands of birds. In due course,
feedlots came into being that carried 50,000 head, and poultry enter-
prises developed that involved over 100,000 birds. Waste production
was concurrently concentrated in large masses. Unfortunately, effi-
cient methods of handling waste materials by no manner kept pace
with improved efficiency in feeding operations. In many instances the
stuff accumulated as miniature mountains. A number of economic
studies indicated that the value of the manure to the land was so
low that it was cheaper for the farmer to get his plant nutrients from
the fertilizer bag than to haul manure from feedlots to the field.
There is indeed a vast materials handling problem when you
consider that total cattle wastes alone amount to 1.4 billion tons a
year. Wastes from all of our domestic livestock come to 1.6 billion
tons; and when bedding, dead carcasses, and the offal from slaughter-
ing are added, the total is close to 2 billion tons a year. Obviously,
large feedlots carrying 100,000 head of cattle produce tremendous
masses of material.
To consider the magnitude of the problem, we have to recognize
that a fattening steer will give off in the neighborhood of 110 pounds
of nitrogen, 125 pounds of potassium, and 365 pounds of biochemical
oxygen demand (BOD) in its excrement each year. This means that
a feedlot with a stocking rate of 200 head per acre will deposit a
really tremendous amount of plant nutrients and readily oxidizable
organic matter on each acre.
The Monfort Feedlot near Greeley, Colorado, carries 90,000
head on 320 acres. The feeding and waste handling procedures are
reallv something to see.
We know that most of the nitrogen deposited on a feedlot goes
into the atmosphere as a result of denitrification processes, but we
also know from soil cores taken from feedlots in Colorado that there
can be deep percolation of nitrate-nitrogen in comparatively high
amounts. We also know some of these nutrients and organic
materials can enter into runoff water.
As a matter of fact, it has been common practice to locate feed-
lots on a hillside above a waterway in order to provide good drainage
and a disposal area for the runoff. Some feedlots traverse a stream
course with the assumption that the stream will carry away the
wastes.
On a smaller scale, we find that even some of the best dairy
farmsteads in the Northeast are built along stream courses so that the
barnyard will drain into the brook. Farmers running dairy farms or
feeder operations in the North prefer to apply manure to the land
during the wintertime when labor demands for other tasks are at a
-------
INTRODUCTION / xxiii
minimum. This means that much of this manure may be spread
right on top of an accumulation of snow. It also means that if there
is rapid snowmelt in the spring, with a comparable rate of runoff,
there will be appreciable amounts of the wastes with plant nutrients
and BOD moving off the fields and into streams. Studies on Lake
Mendota near Madison, Wisconsin, indicate that much of the pollu-
tion coming into that lake during the spring months has its source in
runoff from barnyards or fields on which manure was applied during
the winter.
We must recognize that runoff carrying manure can be a cause
of major fish kills. In fact, the Federal Water Pollution Control Ad-
ministration reports that of 8 major fish kills in 1967, 3 of them
were due to manure drainage (U.S. Department of the Interior, 1968).
It is also of interest that the one really serious fish kill was caused
by food products, which frequently have an effluent exceedingly high
in BOD. It is also of interest that not one of these listed was caused
by pesticides.
Studies in Kansas (Smith and Miner, 1964) show what may
happen in a stream receiving drainage from a feedlot. Their studies
on the Fox River were made at a point about a. mile below a feedlot
during November. Figure C shows that in 20 hours after a 1-inch
storm the water in the stream 1 mile below the feedlot contained 90
ppm of BOD and just about zero ppm of oxygen. Fish cannot survive
if oxygen content of water falls below 4 ppm. At the point of sam-
pling, the BOD dissipated rapidly and the oxygen content of the water
recovered.
It is also important to note that in this study Smith and Miner
found the pollution from fecal coliform bacteria rose to a tremendous
level 20 hours after the storm and then dissipated rather rapidly. By
contrast, the count for fecal streptococcus bacteria rose to an enor-
mous count and continued at that high level of infestation for the
duration of the sampling period (Table A).
As with cattle, the tremendous growth of the broiler industry
in concentrated chicken factories has resulted in the production of
large quantities of manure in local areas.
190
~] FIG. C. Water quality pa-
rameters. (From Smith and
Miner, 1954.)
40 70 80
TIME-HOURS
-------
xxiv / INTRODUCTION
TABLE A. Fox creek bacterial pollution (average counts per TOO ml sample,
Nov. 1962).
Condition
Mean dry weather
After rainfall (11-27)
After rainfall (11-28)
After rainfall (11-29)
After rainfall (11-30) . .
Fecal
Coliform
1,148
542 000
17,200
23 000
7 900
Fecal
Streptococcus
13,800
1 600 000
1,410 000
1 600 000
1 600 000
Source: Adapted from Smith and Miner (1964).
In the Southeast alone, 9 milh'on tons of chicken litter are pro-
duced annually. When this chicken litter is spread on fescue grass
in September at the rate of 16 tons per acre, it supplies 640 pounds
of nitrogen and 250 pounds of potassium per acre. If it is applied
at higher levels, it may even kill the fescue grass and allow useless
weeds to take over. Even a modest application of chicken manure to
fescue pastures will produce fescue hay in November that contains
0.6% nitrate-nitrogen. This grass may not only induce nitrate poi-
soning in the cattle but may also be "grass tetany prone"—that is,
too high in potassium and too low in magnesium.
High applications of chicken litter to oats in late winter will en-
courage a lush growth that is very susceptible to lodging and danger-
ously high in nitrate-nitrogen.
It is not unusual to see cattle that have been eating a high
nitrate forage gather in farm ponds to keep cool. They often pant
continuously. They do this because the nitrate in the grass becomes
nitrite in the rumen, and this causes some of the hemoglobin in their
blood to be changed to methemoglobin, which does not carry oxygen.
In other words, the cattle pant and try to keep cool because of an
oxygen deficiency in their systems.
We hear much about agricultural endeavor causing the eutrophi-
cation of our surface waters. Eutrophication is nutrient enrichment
enabling the growth of plant life in water. It is nature's way of pro-
viding fish food. As already documented, feedlots can be a good
source of plant nutrients. We can see tremendous eutrophication in
drainage ditches in western Minnesota or streams in eastern Mary-
land. Lakes in Minnesota that are completely removed from any
agriculture may accrue an excess of water plants.
We ought to look at this movement of nutrients into water and
recognize that it is more complex than just the supplying of nitrogen
and phosphorus that causes an excess of plant growth. There are
any number of publications on fish production in farm ponds, or fish
farming, that indicate the need for the addition of 800 to 1,200
pounds of 8-8-4 fertilizer per acre of pond surface per year in order
to assure good fish production. This fertilizer is essential to enable
good growth of water plants that provide food for the fish.
Studies on agricultural and wooded watersheds at the U.S. Hy-
drologic Field Station, Coshocton, Ohio, show the phosphorus delivery
per acre per year is only 0.03 to 0.06 pounds. Nitrogen yield from
-------
INTRODUCTION / xxv
the watersheds is appreciably higher but still low in terms of nitrogen
needs of plants for fish food.
If there is an excess of organic matter high in BOD going into
the water along with the nutrients, the depletion of oxygen will kill
the fish—as one can sometimes see along the banks of the Potomac
River. In fact, there are places in the Potomac estuary, below the
Blue Plains sewage disposal facility that dumps into the river, where
nothing seems to grow but ugly water plants. The oxygen content of
this water is so low that the fish which would normally eat some of
the plankton and other plants are eliminated by oxygen deficiency.
Fish can also be eliminated by pesticides. The heavy fish kills
in the Mississippi River in 1964 were alleged to have been caused by
endrin. The source of the suspected endrin was not land runoff.
There have been no end of fish kills attributed to pesticides moving
into water. Here again, if these pesticides kill the fish, ecological
balance is upset; that is, there is no curb on the growth of water
plants. When an overproduction of water plants takes place, some
will die and rot, contributing to further oxygen depletion, nutrient
release, and initiation of a vicious cycle of an abundant plant growth
incurring water environment inimical to the growth and survival of
fish and other faunal life. The process becomes one of forming a
muck bog out of the lake. Yet, we are inclined to the view that plant
nutrients in water should not be considered as pollutants. Rather,
we ought to look upon such nitrogen and phosphorus as potential
protein.
Possibly we should even paraphrase the words of George
Clemenceau when he stated that "war was just too important a matter
to be left in the hands of generals" (Seldes, 1966), and say that water
contamination is just too important a matter to be left in the hands of
sanitary engineers.
Consider a few data.
A good fish pond will produce over 1,000 pounds of fish per acre
per year. One thousand pounds of fish contain 200 pounds of dry
matter, of which 150 pounds are protein that contains 24 pounds of
nitrogen. The conversion factor from plant protein to flesh protein
by foraging fish ranges from 5 to more than 20 to 1. Thus, at least
120 pounds of plant protein nitrogen are needed to produce these
1,000 pounds of fish. However, fish biologists often find P deficiency
in surface waters as the main limiting factor in fish production.
We ought to ask fish and wildlife experts to prescribe optimal
aquatic ecologies for the production of adequate food for abundant
fish not only for man's food and recreation but also for the benefit of
fish-eating wildlife. This will certainly require minimal delivery to
our surface waters of such fish killers as putrescible matter, acids,
sediment, insecticides, and other chemicals. It may also require use
of herbicides with high biochemical specificity on unwanted water
plants. It may mean manipulation of fish population to attain proper
balance between foragers and carnivores.
What are we doing in agriculture to solve water pollution
problems?
First of all, we in agriculture feel strongly that every measure
-------
xxvi / INTRODUCTION
feasible must be taken to minimize or eliminate possible adverse
effects from the use of pesticides. We are now using about a billion
pounds of these chemicals a year. Some of them are very persistent
in the environment; some of them volatilize and become widely dis-
persed; some of them can be very toxic to insects, plants, or wildlife
which we want to protect. And yet we also recognize that it is manda-
tory that the ominous threat of insect pests, diseases, and weeds to
our production of food and fiber must not be ignored. We must ever
seek chemicals carrying a minimum of danger and adverse side
effects. We must seek improved technology in handling and applica-
tion of these chemicals, and wherever feasible, seek methods of
biological control or nonchemical control.
Toward minimizing the damages that may occur from pesticides
and all other pollutants that may occur in runoff from the land, we
must recognize the long-proved advantages of conservation practices
that will curb runoff and soil delivery. Water moving across the land
is completely indiscriminate. It will pick up and move that which is
movable, whether it be soil particles, manure, plant residues, pesti-
cides, fertilizers, or other chemicals. Use of grass waterways has
proved very effective in minimizing the transport of any undesirable
burdens in the runoff water.
We need to develop water diversion structures around our farm-
steads and feedlots so that none of it runs directly into a watercourse,
but rather into a storage lagoon where oxidation of degradable
materials may take place.
Under some conditions there probably ought to be secondary
or even tertiary lagoons to make certain that runoff finally entering
into the watercourse is fairly well reclaimed (less than 20 ppm BOD).
Lagoons have been used with good success around poultry operations
in the South if they were designed to be of adequate capacity and
were operated without intermittent loading.
Some hog operations use lagoons satisfactorily, yet many in the
northern states are failures. They do not control the emanation of
foul odors. There is a large hog operation near Pendleton, Oregon,
that is of interest. The hogwash is collected in lagoons and then dis-
tributed through a large sprinkler irrigation system that covers 140
acres of cropland in one rotation. In this particular operation the
hogwash aids in producing 10 tons of alfalfa hay per acre. The hay
is ground and used as hog feed. The operation is a good example of
recycling of wastes—an objective that should be followed whenever
feasible.
Cattlemen and dairymen in the northern states, where restric-
tions have been imposed on spreading manure on frozen ground, are
using slatted floors with the collection of the excrement in enormous
vats. The liquified manure is spread upon the land by use of either
movable sprinkler systems or large mobile tanks. Many dairymen
have constructed concrete receiving basins for manure that eliminate
runoff to stream channels while enabling the easy operation of load-
ing equipment to get the manure on the land expeditiously.
Let us go back to the Monfort Feedlot in Greeley, Colorado.
The hundreds of thousands of tons of manure produced on this
-------
INTRODUCTION / xxvii
feedlot are picked up by high-efficiency loading equipment and
trucked to over 10,000 acres of land growing corn for cattle feed.
Chopped corn so produced is ensiled in the amount of about 200,000
tons. The ensilage is then mixed with cooked grain by automated
equipment and fed to the cattle by specially designed trucks.
This operation is a very excellent example of the recycling of
wastes.
Finally, we must stress again that a key contribution in making
beneficial use of agricultural wastes, and minimizing any loss of these
wastes from the farm, can take place through sound conservation
farming. It also contributes to beauty of the countryside.
We must make sure that every watershed above our water im-
poundments is effectively protected so the quality of the water in the
reservoir may be used without concern for fishing, recreation, supple-
mental irrigation, and even for municipal water supply. Obviously,
we who are involved in agricultural technology still have a big job
to do.
REFERENCES
Seldes, G. 1966. The great quotations, p. 162. New York: Lyle Stuart.
Smith, S. M., and Miner, J. R. 1964. Stream pollution from feedlot
runoff. Trans. 14th Ann. Conf. Sanit. Eng. Bull. Engineering
and Architecture 52. Lawrence, Kans.: Univ. of Kans. Publ.
Taylor, G. V. 1953. Nitrogen production facilities in relation to pres-
ent and future demand. In Fertilizer technology and resources
in the United States, ed. K. D. Jacob, pp. 15-61. New York:
Academic Press.
U.S. Department of the Interior. 1968. Pollution caused fish kills,
1967. CWA-7.
-------
PART ONE,
SEDIMENT AS A WATER POLLUTANT
-------
CHAPTER ONE.
POLLUTION BY SEDIMENT:
SOURCES AND THE DETACHMENT
AND TRANSPORT PROCESSES
H. P. JOHNSON and W. C. MOLDENHAUER
HILE erosion has been active over geologic time, man has
often altered the process to the detriment of his environment. Con-
sidered by many people more innocuous than sewage, suspended
solid loads delivered to streams and lakes as sediment in surface run-
off are equivalent by weight to more than 700 times the load from
sewage (U.S. Department of Agriculture, 1968). Sediment reduces
water quality and often degrades deposition areas. Sediment pollutes
when it occupies space in reservoirs, lakes, and ponds; restricts
streams and drainageways; reduces crop yields in a given year;
alters aquatic life in streams; reduces the recreational and consump-
tive use value of water through turbidity; and increases water treat-
ment costs. Sediment also carries other water pollutants such as
plant nutrients, chemicals, radioactive materials, and pathogens.
Because the sediment pollution problem is so broad, we do not
attempt to describe the entire problem but do (1) identify problem
areas, (2) define present understanding of the erosion and transport
process, and (3) indicate research needs. We discuss continuum
from field erosion to streams, but our primary emphasis is given to
agricultural aspects of erosion and sedimentation in the humid cen-
tral region of the United States. Only mechanical processes are con-
sidered; chemical and biological processes are omitted. Detailed
coverage of the erosion-sedimentation process is available from sev-
eral sources (Colby, 1963; Einstein, 1964; Gottschalk, 1964; Wisch-
meier and Smith, 1965; Raudkivi, 1967).
To express relatively the status of understanding of the various
H. P. JOHNSON is Professor of Agricultural Engineering, Iowa State
University. W. C. MOLDENHAUER is Research Soil Scientist, ARS-
SWC, USDA, and Professor, Iowa State University.
Contribution from Agricultural Engineering Department, Iowa State
University, Ames, and Corn Belt Branch, Soil and Water Conserva-
tion Research Division, ARS, USDA, Ames. Journal paper No. J-6393
of the Iowa Agriculture and Home Economics Experiment Station,
Ames. Project Nos. 1266 and 1776.
-------
4 / PART 1 / SEDIMENT AS A WATER POLLUTANT
TABLE 1.1. Analysis approaches.
System
Inputs
System
Operation
Limitations
Frequency
diagrams of
system output
Multiple
correlation
Physical
models
Mathematical
models
(deterministic)
Laws of
mechanics
Given little
consideration
Selected then
screened by
statistical
analysis
Specifically
selected;
defined
dimensionally
Equations,
data
describing
processes
Selected data;
appropriate
equations
None defined;
(plot
output)
Defined by
correlation
equations
Model
integrates
inputs
Defined by
flow
diagrams;
equations
solved
Solve
equations
Neglects change in
system with time;
need representative
data over long
period
Need representative
data; accuracy of
results
Range of data;
design require-
ments of model
Accuracy of
equations describ-
ing processes;
input data
Often difficult to
relate to entire
system; often a
component of
mathematical
models
processes involved in erosion and sediment transport, we comment
on approaches to problems. As understanding of a problem improves,
we proceed from empiricism to physical "laws." This should not
condemn empirical approaches; in many instances these are the only
approaches available to planners and designers.
As we proceed from empiricism to laws, however, we are better
able to define the factors involved in a process (inputs) and can
better explain the interaction of the factors (system operation).
Table 1.1 presents an attempt to describe analysis approaches. Al-
though all approaches are used in erosion and sedimentation studies,
the application of mathematical models to unsteady state problems
is only beginning. Most design approaches are based on field ob-
servations, and it is ironical in this time that most design is based
on observation and not on Newtonian physics.
GROSS EROSION FROM LAND
The ability to predict on-site sheet and gully erosion and the
transport of eroded material to a point of concern is extremely im-
portant in planning, design, and economic analysis. The total on-
site sheet and rill erosion (gross erosion) is not delivered to streams.
The amount of sediment that completes the route of travel from the
point of erosion to a point of concern in a watershed is termed sedi-
-------
CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 5
ment yield. The amount of sediment that travels this route involves
factors related to sheet and gully erosion.
Sheet Erosion
EMPIRICAL-THE EROSION EQUATION
In the early 1930s the U.S. Department of Agriculture estab-
lished ten soil erosion research stations. Using some of the data
collected at these and at state stations, Smith (1941), Browning et
al. (1947), and Musgrave (1947) attempted to systematize the calcu-
lation cf erosion losses by using the pertinent causative factors.
In 1954 a Runoff and Soil Loss Data Center was established at
Purdue University by the Agricultural Research Service of the U.S.
Department of Agriculture. All available data from soil and water
loss experiments throughout the United States were assembled for
summarization and analysis. A major result of this summarization
was the so-called Universal Soil Loss Equation (see Wischmeier and
Smith, 1965, for development and use). This equation is A=RKLSCP,
in which A is the computed soil loss in tons per acre, R is the rainfall
factor and is the number of erosion index units in a normal year's
rain. K is the soil credibility factor and is the erosion rate per unit of
R for a specific soil in cultivated, continuous fallow on a 9% slope,
72.6 feet long. L is the effect of slope length and S is the effect of
slope gradient. C is the crop management factor and is the ratio of
soil loss from a field with specified cropping and management to that
from the fallow condition on which the factor K is evaluated. P is the
erosion control practice factor and is the ratio of soil loss with con-
touring, strip-cropping, or terracing to that with straight-row farming
up and down slope. All factors are dimensionless except A and K,
which are in tons per acre, and R which is the number of El units.
R, the rainfall factor, is the rainfall erosion index developed
by Wischmeier (1959) and Wischmeier and Smith (1958). It is the
annual summation of El/100, where E is the kinetic energy of a
rainstorm and I is its maximum 30-minute intensity. The E and I
values can be obtained from recording rain-gage charts. Expected
Iccational values were published in 1962 in the form of an iso-erodent
map (Wischmeier, 1962). The proved high correlation of Ef with
soil erosion has made this equation usable anywhere in the world
where the R and K values can be characterized.
Values of K have been determined for 23 major soils on which
erosion plot studies wrere carried out (Wischmeier and Smith, 1965).
Values for many other soils have been approximated by interpolation
and extrapolation at joint ARS-SCS workshops. Recently, Wischmeier
and Mannering (1969) developed an equation by using multiple re-
gression analyses which estimates K on the basis of soil properties
and their interactions. This equation will allow more accurate de-
termination of K than can be done by interpolation and extrapola-
tion.
The slope length and gradient factors (L and S) are ratios to
field slope losses from a 72.6-foot length and 9^r slope, respectively.
L may be expressed as (A/72.6)"1, where A is field slope length in feet
-------
6 / PART 1 / SEDIMENT AS A WATER POLLUTANT
and m is an exponent determined from field data. S = (0.43 + 0.30s
-f- 0.43s2)/6.613 where s is the slope gradient expressed in percent.
Together they may be expressed as LS = yX(0.0076 -f 0.0053s
+ 0.00076s2).
The cropping management factor C is the ratio of the soil loss
from a field with specified cropping and management to that from
the fallow condition on which the factor K is evaluated. Five crop-
stage periods are used that reflect the changes in plant cover and
surface residues through the year. Productivity level, crop residue
management, crop sequence, plow date, and length of meadow
periods are all considered (Wischmeier, 1960). The erosion control
practice factor P is concerned with only contouring, strip-cropping,
or terracing. Improved tillage practices, sod-based rotations, fer-
tility treatments, and greater quantities of crop residue left on the
field are included in the C factor.
The Universal Soil Loss Equation was developed from many
years of plot data assembled from many locations. In the past 12
years rainfall simulators have been used to update the information
from earlier plot studies and to field test new concepts and prac-
tices (Meyer et al., 1965). Most of the plots used were 72.6 feet long
and 0.01 to 0.025 acre in area. The plot sites represented major
soil types over a large part of the United States. All the plots were
on uniform slopes. Consequently, the more uniform the slope in
the field, the more accurate were the predictions. In developing this
equation for field use, researchers recognized that data were most
lacking for predicting K values and for dealing with more complex
field topography. Onstad et al. (1967), Young and Mutchler (1969),
and others have found that erosion from a concave slope is less than
that from a uniform slope because sediment tends to deposit at the
bottom. Erosion from a convex slope is greater than that from a
uniform slope. Incorporating this type of informaticn into the Uni-
versal Soil Loss Equation can improve predictions. Wischmeier and
Smith (1965) recommend use of the complete slope length with the
gradient of the lower one-third to determine the value of LS for
concave or convex slopes.
The Universal Soil Loss Equation was designed to predict field
losses on an average annual basis. When it is used to predict sedi-
ment content of streams and losses from watersheds, factors must be
added to account for deposition in terraced and bottomland areas ad-
joining streams and for contributions from streambanks and gullies.
It is difficult to check the equation's accuracy on a field basis. The
geometry of most fields does not allow measurement of field soil loss
because of interception above the gaging point. Hadley and Lusby
(1967), however, found very close agreement between measured and
predicted erosion (13 vs. 15 tons per acre). In 1965 at the Treynor
Experimental Watersheds in Iowa, Piest and Spomer (1968) found
measured values in May and early June were greater than predicted.
After early June, predicted values were higher. It is expected that
predicted values would always be higher because sediment deposition
on alluvial and colluvial areas of the watershed would remove some
sediment actually lost from the hillslopes. Higher measured early
losses may be due to development of rills in the plow-through drains
-------
CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 7
as noted by Piest and Spomer. Once the rills reach the depth of the
plowed layer, the rill growth seems to slow considerably or stop alto-
gether where the slope gradient is low. Because of significant inter-
actions of the management and practice factors (C and P) with storm
size and antecedent soil moisture, single-storm or short-term predic-
tions tend to be less accurate than longer-term predictions. Spraberry
and Bowie (1969) correlated total measured sediment from 12 water-
sheds ranging from 243 to 32,000 acres with computed gross erosion.
They found a coefficient of correlation of 0.97 between total measured
sediment and the sum of erosion computed from active gullies and
sheet errosion computed by the Universal Soil Loss Equation. The
coefficient of correlation was 0.95 when the Musgrave (1947) equa-
tion was used. They also found that computed gross erosion from
cultivated land 2% slope and above, and from active gullies, corre-
lated better with total measured sediment yield than the erosion com-
puted from the entire contributing area.
GEOLOGIC MEASUREMENTS
Some studies in geomorphology are cf interest from an agricul-
tural point of view. For example, Leopold et al. (1966) estimated
slope erosion by using a system of pins and washers. They also
studied deposition in an attempt to determine a sediment budget.
They obtained an average value cf surface erosion of 0.015 feet per
year on sparse range vegetation in a semiarid area in New Mexico.
This amounts to an erosion rate of 30 tons per acre per year from
10% slope. They estimated from their data that sheet erosion
is by far the largest source of sediment. Channel deposition is only
about half cf the total sediment trapped, and this is only about one-
quarter of the total sediment produced. They point out that sediment
spread thinly over colluvial areas does not show up in their measure-
ment data. Their sediment accumulation data compare very favor-
ably to those of Hadley and Schumm (1961). Both groups conclude
that sediment accumulation per unit area of basin decreases rapidly
with increasing drainage area. Data of Hadley and Schumm were
also collected in a semiarid area.
Hillslope erosion resulting from runoff from a high-intensity
thunderstorm near Matt, Colorado, was measured by Hadley and
Lusby (1967). They also used pins previously driven in the ground
for measurement of erosion losses. From a 12-acre watershed, they
found an erosion of 18 tons per acre during a 0.90-inch storm with
a 0.51-inch runoff. The maximum intensity of rainfall for a 10-
minute period was 1.98 inches per hour. Here, again, the climate was
arid to semiarid, the average annual precipitation being 8.3 inches.
Although this would not be considered an unusual storm in the Corn
Belt, runoff and erosion of this magnitude from this type of storm
would be highly unusual in the Corn Belt unless antecedent moisture
was very high.
Ruhe and Daniels (1965) measured deposition that had occurred
over a period of several thousand years and for the period from when
the area was first settled until the present. Older deposition rates
-------
8 / PART I / SEDIMENT AS A WATER POLLUTANT
were determined by carbon dating, and deposition rates during the
postsettlement period were measured from tree-ring data. These data
are very interesting, but because of the long periods involved, it is im-
possible to relate the deposition to a postsettlement event or series of
events. Postsettlement (125 years) deposition, however, corresponded
to soil losses of 10 tons per acre per year on an Adair County, Iowa,
site compared with 1.0 ton per year in the preceding 6,800 years.
Some general comments can be made about the applicability of
geological data to the pollution problem. Most of the detailed studies
of erosion seem to be in the arid and semiarid areas. Measurements
are made on the range or pasture land or in badlands areas where
there is little vegetation. Many studies are made on spectacular ex-
amples where land features stand out rather than on more subdued
arable fields. Most estimates are on the basis of deposition and for
long periods—hundreds of years. Shorter-term estimates are seldom
on an individual storm basis. Schumm (1964) emphasizes that the
need for data on erosion processes is pressing, not only as a guide
for better land management, but also as a basis for explaining land
forms as functions of current erosion processes and erosion rates. He
is particularly interested in semiarid regions of the western United
States where erosion proceeds at above average rates.
Schumm (1969) shows the relationship of erosion and deposition
to landform characteristics. Studies such as these are very helpful in
understanding the role of geomorphic processes in field erosion.
RESEARCH APPROACHES-MECHANICS OF EROSION
A concentrated effort is being made by the Soil and Water Con-
servation Research Division of the Agricultural Research Service,
U.S. Department of Agriculture, to develop an erosion model. The
basic model, as now conceived, considers (1) soil detachment by rain-
fall, (2) transport by rainfall, (3) detachment by runoff, and (4) trans-
port by runoff. These are considered as separate but interrelated
phases of soil erosion by water (Meyer and Wischmeier, 1968). An
example of erosion model results is given in Figure 1.1 for a com-
plex slope averaging 8%. Rainfall intensity was 2 inches per hour,
and infiltration rate was 1 inch per hour. Comparable results can be
obtained from a number of slope shapes and rainfall intensity-infil-
tration relationships. The general model can be expanded to a more
detailed one by introducing other components.
The advantage of this model over the empirical model is that
the dynamics of each phase will be described by fundamental hy-
draulic and hydrologic relationships and by parameters describing the
soil properties that influence erosion. Each phase is now being
studied as a segment or submodel by workers at various locations.
Analytical studies of raindrop splash are being carried out, and this
effect is related to soil properties as well as to raindrop size, shape,
and velocity.
Studies of soil particle detachment by raindrops from soil beds
consisting of a number of soil types, conditions of soil management,
and size distribution of clods are being made at Ames, Iowa. Non-
-------
CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 9
60.00 r
40.00
20.00
0.00
10.00
20.00
o AVAILABLE DETACHED SOIL
A TRANSPORTATION CAPACITY
« SEDIMENT LOAD
100.00 150.00
SLOPE LENGTH
SLOPE SHAPE
DEPTH
10.00
0.00
-10.00
NET EROSION LOSS
DEPOSITION (PER INCREMENT)
EROSION (PER INCREMENT)
I I L
_L
0.00 50.00 100.00 150.00 200.00
SLOPE LENGTH
250.00 300.00
FIG. 1.1. Erosion model results plotted for a complex slope averag-
ing 8% steepness. Rainfall intensity was 2.0 in/hr, and infiltration
rate was 1.0 in/hr. Graph ordinates are relative, but the slope units
have been assumed to be in feet and the erosion units may be con-
sidered as pounds per foot of slope width. The upper graph shows
the available detached soil, the transportation capacity, and the re-
sulting sediment load plotted against slope length. The middle graph
shows the slope shape studied with an expanded vertical scale. The
lower graph shows the net erosion loss for each increment. (Meyer
and Wischmeier, 1968.)
cohesive soils (sands) have shown the highest detachment by rain-
drops. When large clods (one-fourth to one inch) were concentrated
on the surface, peak rates of detachment were delayed (Moldenhauer
and Koswara, 1968). Clod stability to raindrop impact was inversely
related to clay content. The higher the content of montmorillonite
clay, the weaker were the clods. Concentrating the large aggregates
in the surface kept the infiltration rate high longer than if they were
mixed with fine material (Moldenhauer and Kemper, 1969). The
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10 / PART 1 / SEDIMENT AS A WATER POLLUTANT
effect of surface sealing on detachment has been studied (Molden-
hauer and Koswara, 1968).
Work is being done to determine the effect of the suction (ten-
sion) gradients on stability, and consequently their effect on detach-
ment and erosion. Plans are being made to develop a computer
model for infiltration, runoff, clod breakdown, and soil detachment
from the beginning of the first rain after tillage throughout each
succeeding rain.
When pore size at the soil surface has been reduced to the point
that rainfall intensity exceeds intake rate, runoff begins. As runoff
water becomes concentrated in the lower areas of the surface mi-
crorelief, small rills begin to form because of detachment and trans-
port of soil by flowing water. This process is being studied at La-
fayette, Indiana.
Gully Erosion
In most areas of the humid region, gully erosion is a relatively
small percentage of gross erosion. A study of 113 watersheds
(Glymph, 1956), ranging from 23 acres to 437 square miles and lo-
cated in the humid area of the United States, showed that sheet and
rill erosion accounted for 90% or more of the sediment yield in half
the watersheds. In about 20% of the cases studied, however, 50%
or more of the sediment was derived from gullies. In most instances
of relatively large sediment production from gullies, watersheds of
less than 1 square mile were involved. In three instances, stream
channel erosion contributed more than 40% of the sediment yield.
In a region of loess-covered sands in Mississippi, gully erosion con-
tributed about 20% of the sediment yield for watersheds ranging
from about 8 to 120 square miles (Miller et al., 1963).
The prediction of gully growth rates has received little atten-
tion, although such information is often needed for design and cost-
benefit analysis for the Public Law 566 program. A study of 61 gul-
lies in the deep-loess area of southwest Iowa (Beer and Johnson, 1963)
related change in gully area to such factors as watershed area, pre-
cipitation, channel geometry, and terraced area. The R2 statistic used
to measure the relative fit (R- measures the percentage of total devia-
tion attributed to regression) varied between 0.70 and 0.89 for 5
linear regression models with 6 or 7 "independent" variables. The
R2s for logarithmic models were lower, but fewer problems with cor-
relation between "independent" variables were encountered. Using
the ratio of the predicted growth rate (equation derived from same
field measurements) to the growth rate measured in the field as a
standard, Beer was able to predict growth rate within 50% in half
the cases. A study (Thompson, 1964) of 210 gully heads located in
6 states related gully advancement to area, a soil factor, rainfall,
gully depth, and channel slope. R2 value for the equation of best fit
was 0.77. An Israeli study (Seginer, 1966) related gully advance to
area. Both Thompson's and Seginer's studies showed the gully head
growth rate to be proportional to the square root of the contributing
watershed area. The scarcity of reported literature and the approaches
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CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 11
taken to date indicate that the mechanics of gully growth are poorly
understood. Predictions of gully growth are usually made by pro-
jecting observed rates obtained from the recent past through use of
aerial photograph measurements and by interview.
SEDIMENT YIELDS
Sediment yields are ordinarily reported in tons per acre per year
in agricultural literature and in tons, or acre-feet, per square mile
per year in engineering and geological literature. The ratio of sedi-
ment yield to gross erosion is termed sediment delivery ratio, a ratio
commonly used in design of small reservoirs. The sediment de-
livery ratio is used to express the fact that the sediment production
per unit area decreases as the watershed area increases. There is
strong evidence to support this as shown in Table 1.2 (Gottschalk,
1964). Even though qualitative reasoning would indicate this is
true, no cause and effect relationships are available to represent the
decrease in the sediment delivery ratio with area. The percentage
of area of lesser slopes increases with drainage area. Groundwater
in contrast to surface water ordinarily contributes a larger percentage
of flow to a stream, and local storms initiate erosion in only a por-
tion of a watershed. From this it would seem that sediment pro-
duction per unit area should decrease with size of watershed if all
other factors remain constant.
The primary sources of sediment-yield information are reservoir
sedimentation surveys and suspended load samplings. Reservoir
surveys have the advantages of providing long-term information in
some instances and of including bed-load sediments (sediment mov-
ing but not in suspension). Disadvantages of the surveys are loss of
sediment through spillage, unavailable individual storm runoff events,
and difficulty in measuring sediment density. A summary of reservoir
sediment deposition surveys is published periodically (U.S. Depart-
ment of Agriculture, 1969). Suspended load samplings have the ad-
vantage of providing data for specific storm events; time required to
obtain long-term records, difficulty in obtaining accurate data, and
cost are disadvantages. Federal agencies are the primary source of
the limited sediment-yield data. Most of the suspended sediment-yield
data are published by the U.S. Geological Survey.
TABLE 1.2. Sediment production rates for drainage areas in the United
States.
Number of
Watershed Size Measurements Average Annual Rate
(square miles) (acre-feet/square mile)
Under 10 650 3.80
10-100 205 1.60
100-1,000 123 1.01
Over 1,000 118 0.50
Source: Gottschalk (1964).
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12 / PART 1 / SEDIMENT AS A WATER POLLUTANT
Sediment Yields from Watersheds
Because of the complexity of the sedimentation process, only
statistical attempts have been used to relate yield to selected ob-
served measurable system inputs. Several regression equations have
been developed, primarily for watersheds less than 50 square miles.
Some estimate of the gross erosion (on-site sheet plus gully erosion)
is required for most of these equations. Other factors related to
drainage density and channel geometry are added.
Glymph (1954) discusses several of the equations. Equations
were developed for South Dakota stock ponds, California forested
watersheds, and western Iowa and Texas watersheds. The equa-
tions typically present sediment yield as some function of climate,
area, watershed geometry, watershed management (if variable), and
relative capacity of the reservoir if predictions are based on reservoir
sedimentation surveys. An example of such an equation (Glymph
et al., 1951) was developed for 36 western Iowa and eastern Nebraska
watersheds ranging in area from 0.036 to 2,800 square miles.
Log S = 1-0078 Log E + 0.6460 Log 10 N - 0.1354 Log 100 W
- 1.4130
where
S = Sediment yield, tons per square mile per year
E = Gross erosion, tons per square mile per year
N = Number of rainfall events (average annual number
equal to or exceeding one inch per day during the grow-
ing season)
W = Net drainage area, square miles.
About 90% of the sediment-yield data points calculated by the
above equation were within ±50% of the points determined by
field measurement.
A more severe test for such prediction equations is to use data
from the same or a similar area (Beer et al., 1966) but independent
of the equation development. Four methods, three based on equa-
tions and one based on gross erosion, delivery ratio, and trap effi-
ciency, were tested by plotting the ratio of predicted yield to measured
yield for 24 reservoirs. Figure 1.2 shows the discrepancy among
equations for the various reservoirs. About 40% of the plotted points
lie in a band in which the actual deposition was predicted within ±
50%.
The sediment delivery ratio approach is used in Soil Conserva-
tion Service watershed designs (Adair and Renfro, 1969). A plot of
delivery ratio against watershed area is defined for a given land re-
source area and is limited to that land resource area. Recent studies
for river basin planning (U.S. Corps of Engineers, 1968) indicate a
similar approach was used in developing logarithmic plots of annual
sediment yield as a function of area for a given land resource area.
Lines for all land resource areas are drawn parallel and indicate an
exponent (slope) of about —0.11. The annual sediment yields rep-
resenting field data range from about 30% to about 300% of the
yields indicated by plotted lines. A similar earlier logarithmic plot
-------
CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 13
50
4-0
Jz3-0
S2
20
LLJ
sio
o
METHOD
• —ILLINOIS
fl 0 •—TP-97
O—GLYMPK
° » A— MODIFIED
GROSS EROSION
O
08
00-6
t
i 0^
0-2
A
• • o
• •* A
s . e . *
I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 2122 23 24
RESERVOIR NUMBER
FIG. 1.2. Comparison of measured reservoir sedimentation with that
predicted by four methods.
(Glymph, 1951) of data from 51 suspended load measurement sta-
tions and reservoirs from different parts of the country showed a
slope of the data envelope lines of about — 0.12. The sediment-yield
plots from the upper Mississippi basin study ranged over three loga-
rithmic cycles for the entire basin drainage area; Glymph's data
ranged over somewhat less than two cycles.
Thus, measurements indicate that extreme variations in sedi-
ment yield may occur in a region made up of different land resource
areas defined by land use, topography, climate, and soil types. Iowa
provides a good example of the effects of topography and soil types
in a region in which agricultural land use is heavy and rainfall char-
acteristics are similar. The relatively flat and recently glaciated area
of north-central Iowa, which is characterized by surface depressions,
has sediment yields of about 50 tons per square mile per year for a
100-square-mile watershed. The rolling loess hills of western Iowa
produce sediment at a rate of about 6,000 tons per square mile per
year for a 100-square-mile watershed (U.S. Corps of Engineers,
1968).
Reservoir Sedimentation
Three aspects of reservoir sedimentation related to delivered
sediment are trap efficiency, specific weight of deposited material,
and distribution of sediment. The trap efficiency of a reservoir is a
-------
14 / PART 1 / SEDIMENT AS A WATER POUUTANT
measure of the efficiency of the structure to retain the incoming sedi-
ment, expressed in percent. The trap efficiency depends primarily
on the particle fall velocity and rate of flow of water through the
reservoir. Trap efficiencies of reservoirs usually decrease with time as
sediment accumulates. Trap efficiency studies (Brune, 1953) indi-
cate most large reservoirs have trap efficiencies greater than 80% .
Brune presented envelope curves of trap efficiency as a function of
the ratio of reservoir capacity (acre-feet) to annual inflow (acre-feet).
Few good data are available on trap efficiency, especially for small
reservoirs.
The specific weight of sediment is needed to obtain a meaningful
measure of deposited sediment. The specific weight is expressed in
terms of dry weight per unit volume in place. Recent studies provide
a measure of in-place specific weight (Heinemann and Dvorak, 1963;
Lara and Pemberton, 1963). The range of specific weights for domi-
nant grain sizes is as follows:
Dominant Grain Size Permanently Submerged Aerated
(pounds per cubic foot)
Clay 40-60 60-80
Silt 55-75 75-85
Sand 85-100 85-100
Specific weights within reservoirs can be estimated if the sand, silt,
and clay percentages and reservoir drawdown characteristics are
known. Lara and Pemberton's data indicate standard errors of pre-
diction of 11 to 14 pounds per cubic foot for 1,316 samples obtained
from many reservoirs under different types of operation. Some river
bed sediments were included. The standard error indicates that
68% of the measured specific weights were within 11 to 14 pounds
per cubic foot of the independently predicted specific weight. The
correlation coefficients (R) ranged from 0.57 to 0.84.
The distribution of deposited sediment is affected by particle size
and velocity of flow through the reservoir. The sediment may be
deposited in the form of a delta at the head of a reservoir or deposited
as a blanket over the bottom of the reservoir. The delta deposits con-
tain primarily the coarser material in transport; the bottom deposits
are primarily clay. Graphs derived for different reservoir shapes
have been developed that indicate the proportion of the sediment lo-
cated below indicated percentages of reservoir depth (Borland and
Miller, 1960). In a study of 23 small reservoirs (Heinemann, 1961),
a regression equation was developed that expressed the percentage
of original reservoir depth filled with sediment in terms of percentage
of original storage depleted, reservoir geometry, storage capacity,
and the capacity-watershed ratio. The coefficient of determination,
R2, for the equation was 0.91. Graphs of sediment distribution were
also presented.
SEDIMENT IN TRANSPORT
Sediment transported by a stream may be divided between bed
load and suspended load, depending on mode of transport. Bed load
-------
CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 15
moves on or very close to the bed, but suspended load is maintained
in the flow by turbulence. Another term sometimes used is "wash"
load or that portion in transport made up of fine particles not found
in quantity in the bed. The term bed-material load describes that
portion in transport of which the bed is largely composed. The bed-
material load may be in suspended transport. Although it is arbi-
trary and depends on velocity, water temperature, and sediment size
available, a division in size may be made at 62-M.
Suspended Transport
The suspended load in transport through a unit width of stream
cross section is determined by the product of concentration times
velocity integrated over the depth of flow. Several measurements of
vertical distribution of sediment are usually taken at a cross section,
except in very small streams. Most samples are taken with a depth-
integrating sampler which intercepts a representative sample in
the profile while the sampler is lowered and raised. The point-integrat-
ing sampler intercepts a water-sediment sample at a point in the pro-
file and enables construction of sediment concentration curves.
In most streams of the humid area of mid-America, most sedi-
ment in transport is suspended. Measurements in the Mississippi
River at St. Louis over 10 years indicated that 95% of the total sedi-
ment discharge was as suspended load; 85% of the suspended load
was silt and clay (Jordan, 1965). In Iowa probably more than 85%
of transported sediment is in suspension; 90% or more of the sus-
pended particles are in the silt and clay range, as indicated from
average particle size distributions cf 7 rivers (Hershey, 1955). Al-
though there are exceptions, most reservoir deposits contain less than
10% sand (Gottachalk, 1964). For 303 samples collected from 32
reservoirs in Illinois the sand content was usually 2 to 5% of the
sample (Stall, 1966).
The capacity of a stream to transport fine particles is restricted
by the available supply; the supply is usually much less than the
stream can convey. In instances where the bed load is appreciable
the supply of particles is usually greater than the stream can trans-
port. Thus the amount transported as bed load depends on flow
characteristics.
The amount of sediment in suspension is extremely variable
and depends on local hydrologic conditions. In general, the sus-
pended load increases faster than the discharge and can be ex-
pressed by L = aQb, where L — sediment load in tons per day, Q is
stream discharge in cfs, and a and b are constants. The constant b
typically lies between 2 and 3 (Leopold and Maddock, 1953). Al-
though the equation roughly expresses the relationship, a scatter
over two logarithmic cycles is not uncommon. The concentration
of suspended sediment is related to climate and physiographic area.
For example, the maximum concentrations of sediment in the por-
tion of the Des Moines River that drains the most recently glaciated
area is seldom over 5,000 ppm, but records for the Soldier River
located in western Iowa deep loess show several concentrations over
-------
16 / PART 1 / SEDIMENT AS A WATER POLLUTANT
200,000 ppm (U.S. Corps of Engineers, 1951). An instantaneous
concentration of 276,000 ppm was sampled in Waubousie Creek of
that region (Hershey, 1955). As indicated previously, the concentra-
tion of suspended sediment in a downstream direction generally de-
creases.
The wash load of a stream travels at about the velocity of the
water. Thus the travel time of clay and silt to a critical downstream
point would be about the same as that of dissolved solids. Bed-load
material would move more slowly because of the nature of transport.
The peak concentrations associated with surface runoff occur near,
and in most cases before, the peak discharge in very small water-
sheds (Dragoun and Miller, 1966). The changes in concentration
with time occur rapidly. In larger watersheds the peak concentra-
tions tend to coincide with the peak flows, although local inflow from
small watersheds may significantly alter concentrations.
The distribution of sediment in a stream varies laterally across
the stream and through the vertical flow profile. Examples indicate
that a variation from the average stream concentration of ± 20%
is common (Task Committee on Sedimentation, 1969). Very large
variations may occur at stream sections below a tributary stream
with different sediment transport characteristics. Sediment par-
ticles in the coarse silt through clay range tend to be uniformly dis-
tributed in the vertical. But the sand concentration gradient de-
creases from the stream bed upward. A mathematical expression
(based on theory of turbulence) is available that defines the concen-
tration gradient for a given particle size, if the concentration of the
given size at a given elevation is known (Rouse, 1938).
Bed Load
Considerable effort has been expended in developing bed-load
formulas, but there is not agreement in the literature regarding
which approach is best (Shulits and Hill, 1968).
Several comparisons have been made (Vanoni et al., 1961; Jor-
don, 1965). Variation between predicted (by formula) and measured
bed loads may be greater than 100%. The most commonly used
formulas are the Einstein, Schoklitsch, and Meyer-Peter and Muller
formulas (Shulits and Hill, 1968). Some of the formulas are used
routinely in planning and operations (Adair and Renfro, 1969).
If the fall velocity (particle size), average stream velocity, and
nature of the channel are known, an estimate of the bed load may
be made. Curves relating bed-material discharge per foot of width
and mean velocity have been developed for sand-bed streams (Colby,
1961). The bed-load discharge may also be estimated in terms of
percentage of suspended load, where data on suspended load are
available (Lane and Borland, 1951). Suspended load concentration,
type of material forming the channel, and texture of suspended
material are needed for the estimate. In some cases where the con-
centration is over 1,000 ppm, channel material is sand or con-
solidated clay, and the suspended material is less than 25% sand,
predicted bed load varies from 2 to 15%.
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CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 17
CONCLUSION
Although considerable progress has been made in the last 30
years, the science of erosion and sediment transport needs to ad-
vance considerably if it is to be sufficiently flexible for use in de-
tailed planning. Most of the approaches to design and planning
are empirically based and are subject to the restraints of the ob-
servations from which they are developed. Considerable study of
on-site erosion and river transport, especially of sand-bed streams in
the West, is evident. The relationship between on-site erosion and
the subsequent response in streams is poorly defined quantitatively.
A few points stand out in relation to pollution. Most material
in transport is in suspension, and is in the silt and clay size range.
Most of the fines in transport in streams are evidently derived from
surface erosion. In regions of erosive soils and well-defined drainage
systems, 10 to 30 tons per acre per year are delivered to streams if
vegetation cover is poor. Concentrations of suspended sediment of
25,000 to 150,000 ppm are encountered for short times. On the
other hand, in flat country with poor drainage development, the
sediment loads and concentrations are relatively low even though
the land is cropped intensively. While bed loads are low, the effect
of man on bed transport may be small.
The works of man are primarily related to change cf cover and
alteration of the hydraulic system through which is transported the
water and sediment. The options of altering cover and channels
remain open.
According to Vanoni (1963):
The theoretical treatment of the sedimentation problem is very diffi-
cult, and will develop slowly. It will be based on the understanding
gained from experiments rather than by some break-through by a
stroke of theoretical genius. However, in order for the experiments to
contribute understanding, they must be designed carefully to answer
certain questions or to prove or disprove hypotheses based on reason-
ing and results of other investigations. Considering the primitive
state of knowledge of sedimentation, contributions can be made in
many ways.
REFERENCES
Adair, J. W., and Renfro, G. W. 1969. Sedimentation considerations
in watershed design. Paper No. 69-209 presented at the meet-
ing of the Am. Soc. Agr. Engrs., June 1969, Lafayette, Ind.
Beer, C. E., and Johnson, H. P. 1963. Factors in gully growth in the
deep loess area of western Iowa. Trans. Am. Soc. Agr. Engrs.
6:237-40.
Beer, C. E., Farnham, C. W., and Heinemann, H. G. 1966. Evaluating
sedimentation prediction techniques in western Iowa. Trans.
Am. Soc. Agr. Engrs. 9:828-33.
Borland, W. M., and Miller, C. R. 1960. Distribution of sediment in
large reservoirs. Trans. Am. Soc. Civil Engrs. 125 (1): 166-80.
Browning, G. M., Parish, C. L., and Glass, J. A. 1947. A method for
determining the use and limitation of rotation and conservation
-------
18 / PART 1 / SEDIMENT AS A WATER POLLUTANT
practices in control of soil erosion in Iowa. Am. Soc. Agron. J.
39:65-73.
Brune, G. M. 1953. Trap efficiency of reservoirs. Trans. Am.
Geophys. Union 34:407-18.
Colby, B. R. 1961. Effect of depth of flow on discharge of bed ma-
'terial. U.S. Geol. Survey Water Supply Paper 1498-D.
. 1963. Fluvial sediments—a summary of source, transporta-
tion, deposition, and measurement of sediment discharge. U.S.
Geol. Survey Bull. 1181-A.
Dragoun, F. J., and Miller, C. R. 1966. Sediment characteristics of
two small agricultural watersheds. Trans. Am. Soc. Agr. Engrs.
9:66-70.
Einstein, H. A. 1964. River sedimentation. In Handbook of applied
hydrology, ed. V. T. Chow, pp. 17-35 to 17-67. New York:
McGraw-Hill.
Glymph, L. M. 1951. Relation of sedimentation to accelerated ero-
sion in the Missouri River Basin. USDA, Soil Conserv. Serv.,
SCS-TP-102.
. 1954. Studies of sediment yields from watersheds. Intern.
Union Geodesy Geophysics, Intern. Assoc. Sci. Hydrol. Publ. 36,
pp. 178-91.
1956. Importance of sheet erosion as a source of sediment.
Trans. Am. Geophys. Union 38:903-7.
Glymnh, L. M., Heinemann, H. G., and Kohler, V. 0. 1951. Unpub-
lished study from files of U.S. Soil Conserv. Serv., Lincoln,
Nebr.
Gottschalk, L. C. 1964. Reservoir sedimentation. In Handbook of
applied hydrology, ed. V. T. Chow, pp. 17-1 to 17-34. New
York: McGraw-Hill.
Hadley, R. F., and Lusby, G. C. 1967. Runoff and hillslope erosion
resulting from a high-intensity thunderstorm near Mack, west-
ern Colorado. Water Resources Res. 3:139-43.
Hadley, R. F., and Schumm, S. A. 1961. Hydrology of the upper
Cheyenne River basin. U.S. Geol. Survey Water Supply Paper
1531-B.: 137-98.
Heinemann, H. G. 1961. Sediment distribution in small floodwater
retarding reservoirs in the Missouri basin loess hills. USDA,
ARS 41-44.
Heinemann, H. G., and Dvorak, V. I. 1963. Improved volumetric
survey for small reservoirs. In Proc. Federal Inter-Agency Sedi-
mentation Conf. USDA Misc. Publ. 970.
Hershey, H. G. 1955. Quality of surface ivaters in loiva. Iowa Geol.
Survey Water SuDply Paper 5.
Jordon, P. R. 1965 Fluvial sediment of the Mississippi River at St.
Louis, Missouri. U.S. Geol. Survey Water Supply Paper 1802.
Lane, E. W., and Borland, W. M. 1951. Estimating bed load. Trans.
Am. Geophys. Union 32:121-23.
Lara, J. M., and Pemberton, E. L. 1963. Initial unit weight of de-
posited sediments. In Proc. Federal Inter-Agency Sedimentation
Conf. USDA Misc. Publ. 970.
Leopold, L. B., and Maddock, T. 1953. The hydraulic geometry of
stream channels and some physiographic implications. U.S.
Geol. Survey Prof. Paper 252.
Leopold, B., Emmett, W. W., and Myrick, R. W. 1966. Channel and
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CHAPTER 1 / SOURCES AND TRANSPORT PROCESSES / 19
hillslope processes in a semiarid area, New Mexico. U.S. Geol.
Survey Prof. Paper 352G, pp. 193-253.
Meyer, L. D., and Wischmeier, W. H. 1968. Mathematical simula-
tion of the process of soil erosion by water. Paper 68—732 pre-
sented at the 1968 winter meeting of the Am. Soc. Agr. Engrs.,
Dec. 10-13, 1968, Chicago.
Meyer, L. D., Mech, S. J., Mutchler, C. K., Hermsmeier, L. F., Palmer,
R. S., Swanson, N. P., Brubenzer, G. D., and Moldenhauer, W. C.
1965. Symp. on simulation of rainfall for soil erosion research.
Trans. Am. Soc. Agr. Engrs. 8:63-75.
Miller, C. R., Woodburn, R., and Turner, H. R. 1963. Upland gully
sediment production. Intern. Assoc. Scientific Hydrol., Com-
mission of Land Erosion Publ. 59, pp. 83-104.
Moldenhauer, W. C., and Kemper, W. D. 1969. Interdependence of
water drop energy and clod size on infiltration and clod stability.
Soil Sci. Soc. Am'Proc. 33:297-301.
Moldenhauer, W. C., and Koswara, J. 1968. Effect of initial clod
size on characteristics of splash and wash erosion. Soil Sci. Soc.
Am. Proc. 32:875-79.
Moore, C. M., Wood, W. J., and Renfro, G. W. 1960. Trap efficiency
of reservoirs, debris basins, and debris dams. Am. Soc. Civil
Engrs. Proc. J. Hydraulics Div. 86, HY2:69-87.
Musgrave, G. W. 1947. The quantitative evaluation of factors in
water erosion, a first approximation. /. Soil Water Conserv.
2:133-38.
Onstad, C. A., Larson, C. L., Hermsmeier, L. F., Young, R. A. 1967.
A method of computing soil movement throughout a field.
Trans. Am. Soc. Agr. Engrs. 10:742-45.
Piest, R. F., and Spomer, R. G. 1968. Sheet and gully erosion in the
Missouri Valley loessial region. Trans. Am. Soc. Agr. Engrs.
11:850-53.
Raudkivi, A. J. 1967. Loose boundary hydraulics. 1st ed. New York:
Pergamon Press.
Rouse, H. 1938. Fluid mechanics for hydraulic engineers. New
York: McGraw-Hill.
Ruhe, R. V., and Daniels, R. B. 1965. Landscape erosion—geologic
and historic. /. Soil Water Conserv. 20:52-57.
Schumm, S. A. 1964. Seasonal variations of erosion rates and proc-
esses on hillslones in western Colorado. Ann. Geomorphol. Sup-
plement 5:215-38.
. 1969. A geomorphic approach to erosion control in semi-
arid regions. Trans. Am. Soc. Agr. Engrs. 12:60—68.
Seginer. I. 1966. Gully development and sediment yield. Israel
Ministry of Agr. Soil Conserv. Div. Res. Rept. 13.
Shuh>s. S.. and Hill, R. D. 1968. Bedload formulas. University
Park, Pa.: Dept. Civil Eng. Hydraulics Lab. Bull.
Smith, D. D. 1941. Interpretation of soil conservation data for field
use. Agr. Eng. 22:173-75.
Spraberry, J. A., and Bowie, A. J. 1969. Predicting sediment yields
'from complex watersheds. Trans. Am. Soc. Agr. Engrs. 12:199-
201.
Stall, J. B. 1966. Man's role in affecting the sedimentation of streams
and reservoirs. 111. State Water Survey Reprint Series 68.
Task Committee on Sedimentation. 1969. Sediment measurement:
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20 / PART 1 / SEDIMENT AS A WATER POLLUTANT
fluvial sediment. Proc. Am. Soc. Civil Engrs. 95 (HY5): 1477-
1514.
Thompson, J. R. 1964. Quantitative effect of watershed variables on
rate of gully-head advancement. Trans. Am. Soc. Agr. Engrs.
7:54-55.
U.S. Corps of Engineers. About 1951. Suspended sediment in the
Missouri River, daily record for water years 1937—1948. Corps
of Engrs., Missouri River Div., Omaha.
. 1968. Fluvial sediment. In Upper Mississippi River compre-
hensive basin study, Draft 3, appendix G. North Central Div.,
Chicago.
U.S. Department of Agriculture. 1968. A national program of re-
search for environmental quality. Joint Task Force Rept. of the
USDA and the state universities and land-grant colleges.
. 1969. Summary of reservoir sediment deposition surveys
made in the United States through 1965. Misc. Publ. 1143.
Vanoni, V. A. 1963. Review of research activities in sedimentation.
In Proc. Federal Inter-Agency Sedimentation Conf. USDA Misc.
Publ. 970.
Vanoni, V. A., Brooks, N. H., and Kennedy, J. F. 1961. Lecture notes
on sediment transportation and channel stability. Pasadena,
Calif.: W. H. Keck Lab. of Hydraulics and Water Resources,
Calif. Inst. of Technol. Rept. KH-R-1.
Wischmeier, W. H. 1959. A rainfall erosion index for a universal
soil-loss equation. Soil Sci. Soc. Am. Proc. 23:246-49.
. 1960. Cropping-management factor evaluations for a uni-
versal soil-loss equation. Soil Sci. Soc. Am. Proc. 24:322—26.
1962. Rainfall erosion potential. Agr. Eng. 43:212-15.
Wischmeier, W. H., and Mannering, J. V. 1969. Relation of soil
properties to its credibility. Soil Sci. Soc. Am. Proc. 33:131-37.
Wischmeier, W. H., and Smith, D. D. 1958. Rainfall energy and its
relationship to soil loss. Trans. Am. Geophys. Union 39:285-91.
. 1965. Predicting rainfall-erosion losses from the cropland
east of the Rocky Mountains. USDA Handbook 282.
Young, R. A., and Mutchler, C. K. 1969. Effect of slope shape on
erosion and runoff. Trans. Am. Soc. Agr. Engrs. 12:231-33,
239.
-------
CHAPTER TWCi
CHEMISTRY OF SEDIMENT
IN WATER
R. F. HOLT, R. H. DOWDY, and D. R. TIMMONS
T
§ HE sediment that is carried off sloping lands and transported
into surface water supplies has been called the greatest single pollut-
ant of our natural waters. In a certain sense its physical effects are
much more obvious than its chemical effects. The clogging of navi-
gation channels and the silting of lakes and reservoirs are expressions
of the physical existence of the sediment. It is also a costly existence,
for millions of dollars are spent annually for dredging operations to
remove this material from its place of deposition. Relatively little
is known about the chemical effects of sediment on the water supply
in which it resides or its influence on the chemical status of flowing
water during transport.
There has been growing concern for the quality of surface
waters, particularly in terms of the nutrient levels that permit
nuisance growth of aquatic plant life. The two elements most closely
associated with these noxious growths are nitrogen and phosphorus.
These elements are also closely associated with agriculture, for they
occur in all plant life. Since these are the chemicals most apt to be
in insufficient supply for crop growth, they are the nutrients most
frequently supplied as fertilizers. Fertilizers are applied to the sur-
face of soils and thus are quite vulnerable to removal by erosion. It is
this eroded topsoil which makes up the bulk of the sediment being fed
into surface water supplies, and it is this material that we are con-
cerned with in this discussion.
CHARACTER OF THE SEDIMENT
The mineralogical composition of sediment, both suspended and
bottom material, is as complex as that of the soil from which it was
R. F. HOLT is Soil Scientist, USDA, and Professor, University of Min-
nesota. R. H. DOWDY is Soil Scientist, USDA, and Assistant Profes-
sor, University of Minnesota. D. R. TIMMONS is Soil Scientist, USDA.
Contribution from the Corn Belt Branch, Soil and Water Conserva-
tion Research Division, ARS, USDA, Morris, Minn., in cooperation
with the Minnesota Agricultural Experiment Station.
21
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22 / PART 1 / SEDIMENT AS A WATER POLLUTANT
derived. Little is known about the mineralogical composition of nat-
ural water sediments. However, from soil erosion literature it has
been established that erosion is selective (Massey and Jackson, 1952;
Massey et al., 1953). While a discussion of soil erosion is beyond the
intent of this chapter, some observations are appropriate. Manner-
ing and Wischmeier1 observed that the sediment from five soils con-
taining 60 to 75% silt was higher in silt than the original soil. It was
also observed that clay was preferentially removed from two soils of
high sand content.
Working with a Connecticut watershed, Frink (1969) reported a
large decrease in sand content of the lake sediment compared to that
of the watershed soils, 18 and 60 to 65% , respectively. On the other
hand, the clay content of the sediment was fivefold greater than that
of the upland watershed soils. Similarly, the silt content increased
from 20 to 25% for the watershed soils to 34% for the lake sediment.
Stall (1964) reported the following representative comparison be-
tween Illinois lake sediments and the watershed soils from which they
were derived: (1) the sand content of the two remained the same at
approximately 5% and (2) the clay content of the sediment was 39%
compared to a 15% clay content for the watershed soils. These types
of observations strongly support the hypothesis of the selective, size-
sorting nature of erosion. It is the product of this erosion that be-
comes the colloidal stream load and sediments of natural waters.
The clay mineralogy of sediment reflects the mineralogy of the
soils from which it was derived. Frink (1969) identified vermiculite
(40%), "illite" (hydromica, 35%), and kaolinite (25%) in the lake
sediment he studied. Vermiculite concentration decreased in the
sediment compared to that of the watershed soils, while illite and
kaolinite concentrations increased. In the southeastern United States
where kaolinite is the predominant clay mineral in soils, it is likewise
observable in the sediments of that region (Pomeroy et al., 1965).
Sediments derived from western Minnesota soils high in montmoril-
lonite contain montmorillonite as the major clay mineral (Burwell et
al.2). Working with a Tennessee lake bed sediment, Lomenick and
Tamura (1965) observed that "illite" (hydromica) was the predomi-
nant clay mineral present in the sediment as well as in the shale for-
mations of the surrounding area. Information as to the presence of X-
ray amorphous clay material (i.e., crystalline relics, amorphous Fe,
and Al hydrous oxides) is indeed limited, but this material must exist
in young sediments and suspended water load if these clay size par-
ticles were present in the source materials. Work by Frink (1969)
showed the presence of free Fe oxides in a neutral, freshwater lake.
The free Fe oxide content was highly correlated with the clay content
of the sediment which suggested that this material also obeys size
sorting.
The chemistry of sediments is in reality the surface chemistry
and properties of the colloidal (inorganic and organic) fraction of
those sediments. To understand the behavior of the colloids, one must
1. Personal communication.
2. Unpublished data.
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CHAPTER 2 / CHEMISTRY OF SEDIMENT / 23
first look at the structure and characteristics of the colloidal material.
For a complete discussion of clay minerals, the book by Grim (1968)
is recommended.
Clay minerals are defined as two-dimensional arrays of Si/O
tetrahedra and Al/ or Mg/O/OH octahedra. In soil science we often
use the term "clay" to include all inorganic particles 2^ in equivalent
spherical diameter. Hence, clay could include 2/x quartz as well as
hydrous Fe and Al oxides. The structure of clay minerals is the super-
imposition of tetrahedral and octahedral sheets in many different
arrays. When one tetrahedral and one octahedral sheet are super-
imposed to form a layer, the resultant is referred to as 1:1 type clay
mineral or the kaolin group. The 2:1 type clay minerals are charac-
terized by two tetrahedral sheets sharing a central octahedral sheet.
For both the 2:1 and 1:1 type clays, the crystals are formed by the
stacking of unit layers with a constant periodicity. The third type of
clay minerals is the 2:1:1 minerals or the chlorite group. It is
formed by interlayering 2:1 type minerals with a brucite sheet (either
iron, aluminum, or magnesium hydroxide or any combination);
hence, 2:1:1 type minerals.
From a physicochemical perspective, the two most important
properties of clay colloids are electrical charge and surface area. To
discuss these characteristics in any detail is beyond the scope of this
chapter; however, the magnitudes of these properties for some clay
materials are shown in Table 2.1. As a general rule, clays carry a
net negative charge. This negative charge arises from two sources:
(1) isomorphous substitution in the crystal structure, and (2) broken
bonds on crystal edges. Isomorphcus substitution refers to the re-
placement of tetravalent Si by trivalent Al in the tetrahedral sheet
of a clay crystal and/or replacement of trivalent Al by divalent cations
such as Mg in the octahedral sheet. This type of substitution gives
rise to a permanent negative charge on the clay crystal which is
balanced by a surface layer of cations too large to penetrate to the
crystal structure which can be replaced by another cation—hence
the term exchangeable cation. The site and magnitude of this sub-
stitution are used to differentiate clay minerals. Vermiculite is substi-
tuted in the tetrahedral sheet, while montmorillonite is substituted
octahedrally. For this reason and the fact that vermiculite possesses
TABLE 2.1. Cation exchange capacity and surface area of several clay
minerals.
Cation Exchange Surface
Clay Capacity Area
(me1100 g) (M'/g)
Vermiculite 100-150 600-800
Montmorillonite 80-120 600-800
Hydromica 10-40 65-100
Chlorite 10-40 25-40
Kaolinite 3-15 7-30
Hydrous oxides 2-6 100-800
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24 / PART 1 / SEDIMENT AS A WATER POLLUTANT
a higher surface charge, montmorillonite will expand more readily
and to a greater extent in aqueous solutions than does vermiculite. In
contrast to these expanding 2:1 type clay minerals, hydromica has a
much higher surface charge which is satisfied with K ions. The elec-
trostatic interactions in hydromica are so great that expansion upon
hydration is not observed generally. Hence, the K ions are non-
exchangeable, with the result that hydromica has a lower exchange
capacity than vermiculite or montmorillonite.
Kaolinite has very little isomorphous substitution (permament
charge). Its ion exchange capacity is derived from a second source of
charge, which is broken bonds at the edges of crystals. The charge
arising from broken bonds is a function of particle size and pH. As
particle size decreases, so does the ion exchange capacity. It may be
either positive or negative, depending upon the pH of the system.
However, for pH values in the neutral and alkaline range,'the edge
charge will be neutral or negative (Schofield and Sampson, 1954).
Other clay minerals have similar pH-dependent charge, but such
charge becomes of less importance as the permanent negative
charge increases in magnitude. Amorphous, clay size, hydrous
oxides of Fe and Al possess positive charges due to the protonation
of a formerly shared OH group—for example [(— OHo)^] (Rich,
1968).
Organic colloids are a significant constituent of natural sedi-
ments. Losses of organic matter in eroded soil can be as high as
1,100 pounds per acre (Barrows and Kilmer, 1963). Since organic
matter is concentrated in the soil surface and has a low density, it
is among the first components to be removed. Thus, the eroded soil
contains more organic matter than the surface soil from which it
came, and enrichment ratios of about 1 to 5 have been reported.
Unfortunately, little definitive information is known about the phys-
icochemical character of this material, perhaps due to the lack of
understanding of the chemical character of soil organic matter from
which it is derived. The organic colloids may be cationic and/or
anionic in nature or exist as neutral entities with functional groups
such as hydroxyl, carboxyl, and amino, which may ionize in the same
manner as other organic compounds. If organic colloids of sedi-
ments bear any relationship to those in the soils from which they
were derived, a cation exchange capacity from 250 to 400 me/100 g
soil can be expected. What role selected erosion may play in the
qualitative nature of the organic sediment is unknown. Likewise,
the physicochemical character of organic colloids produced in natural
waters is unknown.
Chemical reactions of sediments with the properties discussed
above can be divided into two groups: (1) interactions with charged
ions, and (2) interactions with neutral compounds. Adsorption of
charged ions by colloids is referred to as ion exchange and is the
straightforward process of maintenance of electrical neutrality by
the interaction of oppositely charged species. Both inorganic and
organic cations are adsorbed on negatively charged clay colloid sur-
faces. The ease or difficulty with which an inorganic cation can re-
place an adsorbed cation is dependent upon numerous factors which
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CHAPTER 2 / CHEMISTRY OF SEDIMENT / 25
include (1) cation concentration, (2) complementary adsorbed cation,
(3) solution anion, (4) nature of the clay mineral, (5) temperature of
suspension, and (6) nature of replacing the cation. These factors are
discussed by Grim (1968). As a general rule, the higher the valence,
the greater the replacing power of an ion. Also, the replacing power
for ions of the same valence tends to increase with increasing atomic
radius and decreasing hydration.
Cation exchange can play a very important role in the chemistry
of natural waters. In some instances, cesium-137 is a major radionu-
clide contaminant of natural waters (Lomenick and Tamura, 1965).
Sawhney (1964) and Colman et al. (1963) have shown that vermicu-
lite and hydromica fix Cs against Ca extraction. Lomenick and
Tamura (1965) observed that hydromica in lake sediments fixed large
quantities of Cs-137 from contaminated wraters. Hence, .sediments
can serve as chemical scavengers of contaminated natural waters.
Diagenesis of illite from vermiculite by the exchange and fixation of
K from lake waters as suggested by Frink (1969) is another important
exchange reaction in nature.
Adsorption of anions such as phosphates is of great interest to
those concerned with the fate of nutrients in natural waters. Rich
(1968) stated that amorphous Al and Fe hydrous oxides and hydrox-
ides are the most reactive soil colloids with respect to anion adsorp-
tion. This type of reaction is an electrostatic interaction. Anions
may also enter into exchange with hydroxyl groups exposed at the
broken edges of crystals or on the surfaces of amorphous hydrous
oxides. By studying the adsorption of sulfate in soil suspensions,
Chao et al. (1965) concluded that sulfate ions were exchanging for
"structural" hydroxyl groups. It is suggested that reactions of the
same type can occur in natural colloidal suspensions.
The second type of adsorption on sediments is the interaction
of colloids with neutral polar molecules. In natural waters it must be
remembered that water is the solvent and that one is studying an
aqueous system. Hence, in any equilibrium adsorption reaction, the
adsorbate is competing with an extensively hydrated adsorbent. This
is why Hoffmann and Brindley (1960) observed that adsorption of
alcohols from aqueous suspensions of montmorillonite did not occur
until the compound contained five or six carbon atoms. This same
phenomenon occurs in the adsorption of sugars onto clays. Clapp
et al. (1968) reported the adsorption of polysaccharides on montmoril-
lonite from aqueous suspension, while it is not possible to show an
adsorption of mono- and disaccaride under the same conditions
(Dowdy3). While an exact division between adsorption and no adsorp-
tion of sugars on a size basis cannot be made, it is possible that mo-
lecular weights in the tens of thousands are required before adsorp-
tion occurs from aqueous suspension. However, once adsorption of
uncharged polymers occurs, it is very difficult to remove them from
the clay surface (Greenland, 1963). This very strong interaction can
be explained by the development of many weak polymer-surface
bonds (van der Waals. H-bonding) and the statistical improbability
3. Unpublished data.
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26 / PART 1 / SEDIMENT AS A WATER POLLUTANT
of simultaneous rupture of all bonds at a given time (Greenland,
1965). In light of the above discussion, the published information
about adsorption of neutral polar molecules must be studied very
critically, if extrapolations are to be made to sediments in natural
waters.
Lotse et al. (1968) determined that adsorption of lindane on
lake sediments from aqueous suspensions was correlated significantly
with both clay and organic matter content of the sediment. In some
cases the interactions of clay with organic compounds can enhance
adsorption reactions. Lee and Hoadley (1967) showed that the sorp-
tion of organic materials from natural water onto clays activated
new adsorption sites. They noted increased adsorption of parathion
on the clay-organic complex versus adsorption on clay alone. Hence,
in some natural situations it may be possible to observe "chemical
scavenging" of uncharged pollutants in natural waters.
Another physicochemical phenomenon worthy of note in nat-
ural waters is the production of sediments by precipitation. Theabold
et al. (1963) observed the precipitation of hydrous oxides of Fe, Al,
and Mn when waters containing these elements came into contact
with a body of water of sufficiently high pH. Once formed, these
hydrous oxides enter into other chemical reactions such as the ad-
sorption of phosphates. In aquatic environments supporting photo-
synthesis, it is possible to have sufficient CCX evolved to increase the
pH of the water to exceed the solubility product of CaCO3—hence,
precipitation of CaCO3. Upon cessation of photosynthesis, Lee and
Hoadley (1967) suggest that the pH will return to its original equi-
librium level, followed by solution of the precipitated CaCO3. How-
ever, Chave (1965) observed that in some situations CaCO3 did not
redissolve and postulated that it had been coated with resistant or-
ganic material. Lee and Hoadley (1967) also stated that Sr2+, Pb2+, and
Zn2+ can be co-precipitated with CaCO3 if present in the given system.
OXIDIZED AND REDUCED ZONES IN SEDIMENTS
A waterlogged soil becomes differentiated into a surface-oxidized
layer and an underlying reduced layer. The thickness of this oxidized
zone has been reported to vary from 1 or 2 millimeters to several
centimeters with an average of about 20 mm (Mortimer, 1942; Gor-
ham, 1958; Holden, 1961; Patrick and Mahapatra, 1968). There is
general agreement among researchers that these zones exist, but
different mechanisms have been proposed as to how the two layers
are formed and maintained.
Mortimer (1942) described the existence of an oxidized zone and
believed this oxidized layer was maintained by the diffusion of oxygen
from water into the sediment. He suggested the distance of this diffu-
sion into the sediment during winter depended mainly upon the re-
ducing power of the sediment. In waterlogged soils, Patrick and
Mahapatra (1968) stated the thickness of the oxidized layer is deter-
mined by the net effect of the oxygen consumption rate in the soil and
the oxygen supply rate through the overlying water. A soil with an
abundant source of organic matter (energy) will utilize oxygen
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CHAPTER 2 / CHEMISTRY OF SEDIMENT / 27
faster than it can be supplied through the water, and this high con-
sumption rate results in a thin oxidized zone. When the oxygen con-
sumption rate is low, the oxidized layer becomes thicker.
Gorham (1958) suggested the thickness of the oxidized zone of
lake sediment may depend on two factors: (1) the turbulent displace-
ment of the uppermost sediments into the overlying aerated water,
and (2) the reducing power of the sediments. When sedimented
plankton decomposes, the winter oxidized zone may disappear from
the surface downward because of the greater oxygen consumption.
Gorham placed more emphasis on the turbulent mixing of the sedi-
ments with aerated water than on the reducing power of the sediment.
Regardless of the exact mechanism involved in forming the oxidized
and reduced zones, these two layers are extremely important in con-
versions and equilibrium phenomena involving chemical nutrients.
When soils are submerged, the oxidation-reduction (redox) po-
tential decreases. Patrick and Mahapatra (1968) reported a range
of —300 to +700 millivolts redox potential in waterlogged soils. Since
aerated soil measures about 400 to 700 millivolts potential, it appears
the oxidized layer of sediment would be within this same range, and
the reduced layer redox potential should range from —300 to +400
millivolts.
The reduction of oxidized inorganic components is generally a
sequence of the various redox systems (Fig. 2.1). Oxygen was found
to disappear at +320 to +340 millivolts (Turner and Patrick, 1968),
nitrate became unstable at +225 millivolts (Patrick, 1960), ferric
iron was reduced at +120 millivolts (Patrick, 1964), and sulfate re-
duction started at —150 millivolts (Connell and Patrick, 1968).
Usually the reduction of one component is not completed before re-
duction of the next most easily reduced component begins.
REACTION OF NITROGEN FORMS WITH SEDIMENT
The chemistry that is important in the influence of sediments
on the quality of water involves the nitrogen and phosphorus rela-
tions between the sediment and the water. Nitrogen relationships are
difficult to study because many conversions to different forms occur
for different biological and chemical conditions.
When sediment is transported to surface waters, it contains
so.
NO,
1 1
-V//////////////A
i i
1
i
1
1
i i i i
-200
+ 200 +400 +600
FIG. 2.1. The approximate
oxidization-reduction po-
tentials at which oxidized
forms of several inorganic
redox systems become un-
stable. (After Patrick and
Mahapatra, 1968.)
REDOX POTENTIAL-MILLIVOLTS
(CORRECTED TO pH 7)
-------
28 / PART 1 / SEDIMENT AS A WATER POLLUTANT
NHI
—*-HN02 —
(NITRIFICATION)
HN03
HNO.
LEACHING
I
- HN03
(DENITRIFICATION)
•WATER
OXIDIZED
SOIL LAYER
•REDUCED
SOIL LAYER
FIG. 2.2. A schematic diagram of the processes by which ammonium
fertilizer can be lost from a waterlogged soil. (After Mitsui, 1954.)
nitrogen in the forms of organic-, NH4-, NO2-, and NO3-N. Before
being deposited the sediment will probably lose soluble organic-, NO2-,
and NO3-N, whereas the insoluble organic N and NH4-N will essen-
tially remain with the sediment. Flooded soils would react similarly
except losses of the soluble components would probably be slower be-
cause more diffusion and less turbulence would be involved.
The scheme for nitrogen reactions in submerged soils has been
depicted by Mitsui (1954) and is shown in Figure 2.2. Under anaero-
bic conditions, nitrogen mineralization cannot proceed past the NH4-N
stage because insufficient oxygen is available to convert NH4-N to
NO3-N. Since the organisms involved in anaerobic organic matter
decomposition are less efficient than their aerobic counterpart, the
conversion of organic matter to NH4-N is slower in waterlogged soils
(Tenny and Waksman, 1930). Although the conversion rate was
slower in waterlogged soils, Waring and Bremner (1964a, 1964b)
found that more nitrogen was mineralized for several soils under
waterlogged conditions than under aerobic conditions.
According to Patrick and Mahapatra (1968), denitrification is
one of the major mechanisms by which nitrogen is lost from a
flooded soil. In the oxidized zone, NH4-N from organic matter decom-
position or already present on the sediment base exchange is con-
verted to NO3-N. This NO3-N either diffuses or is leached into the re-
duced zone where it is converted by certain facultative anaerobic or-
ganisms to No or NoO and lost to the atmosphere. Broadbent and
Stojanovic (1952) found that only 0 to 6% of the NO,-N denitrified
in a waterlogged soil was reduced to NH4-N. Only in specialized
cases is NH4-N volatilization an important mechanism of nitrogen
loss from a waterlogged soil.
The rate of NO3-N reduction after submergence of a soil can be
quite rapid. With no additional energy source, Patrick (1960) re-
ported a NO3-N reduction rate of 15 ppm per day in reduced soil,
whereas Bremner and Shaw (1958a, 1958b) recorded a loss of 1,000
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CHAPTER 2 / CHEMISTRY OF SEDIMENT / 29
ppm NO3-N in 4 days from a submerged soil which had an energy
source added.
Sediments are apparently poor conservers of nitrogen supplies.
Attempts to overcome poor utilization of fertilizer nitrogen by rice
under flooded conditions have resulted in the development of a sys-
tem in which denitrification of added nitrogen is minimized. This
involves deep placement of ammonia nitrogen in the reduced soil
layer where it is protected from nitrification and subsequent denitri-
fication.
The increase of fresh organic material to the surface sediments
in lakes and reservoirs by the periodic deposition of aquatic vegeta-
tion should create conditions favorable for the rapid loss of NO3-N,
with perhaps slight increases in NH4-N.
REACTION OF PHOSPHORUS WITH SEDIMENT
When phosphorus is added to an aerated soil, it is converted
rapidly to water-insoluble forms and becomes extremely immobile.
If the soil is submerged continuously or becomes sediment in a lake
or stream, there may be a marked increase in the availability of
native and applied phosphorus compared to well-aerated conditions.
The mechanism of this phosphate release, as given by Patrick and
Mahapatra (1968), consists of (1) reduction of insoluble ferric phos-
phate to the more soluble ferrous phosphate, (2) release of occluded
phosphate by reduction of the hydrated ferric oxide coating, (3) dis-
placement of phosphate from ferric and aluminum phosphates by
organic ions, (4) hydrolysis of ferric and aluminum phosphates, and
(5) phosphate exchange between clay and organic anions. However,
the phosphate that becomes soluble from reduction of ferric phos-
phate can be refixed if sufficient alumnium is available, and can also
be refixed as ferric phosphate if Fe2t is oxidized to Fe3+ in the oxidized
zone. Thus, submergence of soil does not necessarily increase phos-
phate solubility and availability.
Under waterlogged conditions, organic matter affects the mech-
anisms of reduction and chelation. Shapiro (1958) reported both
processes increase soil phosphate solubility and availability, so the
addition of organic matter to the surface of sediments should create
conditions favoring increased availability of phosphorus. However,
others (Bartholomew, 1931; Paul and DeLong, 1949) have reported
that a transformation of inorganic phosphorus to the organic form
in flooded soils reduced the availability of the phosphorus. It is a
complex system and contradictory findings are not unusual.
The equilibrium reactions involving phosphorus in sediments,
water, and aquatic plants are influenced by many biological, chem-
ical, and physical factors, making this dynamic system very difficult
to study in situ. Studies using radiophosphorus placed either in the
bottom sediments or in the surface water have provided needed data
about the behavior of phosphorus.
Rigler (1956) found that only 3% of the radiophosphorus added
to the surface of a small, acid-bog lake was lost to the sediments.
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30 / PART 1 / SEDIMENT AS A WATER POLLUTANT
He concluded there was a turnover of "mobile" phosphorus of the
epilimnion with phosphorus of the littoral organisms in 3.5 days.
The turnover time (in summer) for soluble inorganic phosphorus
was about 5 minutes. Hayes et al. (1952) reported that lake sedi-
ment increased in radiophosphorus for 10 days after deposition in
the lake surface, but suggest that in addition to the sediments, aquatic
organisms are very active in the exchange process.
Using sediment core samples in the laboratory, Holden (1961)
concluded that bottom sediment can slowly take up large amounts
of phosphate and that about 85% of the phosphate removed by the
sediment occurred in the aerobic zone which extends to about 20 mm.
In unfertilized lakes, the phosphorus content of the sediment surface
was very high relative to the equilibrium concentration in the over-
lying water.
Harter (1968) also found that lake sediment can absorb a large
amount of phosphorus from the water. When more than 0.1 mg
phosphorus was added it was adsorbed in a loosely bonded form,
and he suggests that large influxes of phosphorus into a lake may
be held temporarily and subsequently released to aquatic plants.
Phosphorus equilibria between lake bottom sediments and cal-
cium phosphate solutions were studied on samples collected from
two eutrophic lakes in western Minnesota (Latterell et al.4). When
solutions containing up to 42 ppm phosphate were equilibrated with
sediment, the resulting solutions contained about 0.03 ppm phos-
phate, so the sediment adsorbed large amounts of orthophosphate.
The release of phosphorus from lake sediments to lake water
was investigated for several lakes at Madison, Wisconsin, by Sawyer
et al. (1944). They reported that continuous leaching of 1-liter sedi-
ment samples for 220 days released 12 and 5 mg of phosphorus
from Lake Monona and Lake Waubesa sediments, respectively, as
compared to 180 and 90 mg from undigested sewage sludge and
storm sewer sludge for these two lakes, respectively. The amount
of phosphorus removed by this continuous leaching, however, does
not indicate the equilibrium concentration.
Diffusion of phosphorus from sediment into the overlying water
is negligible in undisturbed systems. Hasler (1957) found that the
percentage as well as the amount of phosphorus released to the
superimposed water was very small when it was placed at depths
greater than 1 cm.
In a similar study, Zicher et al. (1956) reported that phosphorus
placed at y2 inch below the sediment surface showed only a very
slight tendency to diffuse into the above water and did not diffuse
into the water at all when placed at 1-inch depth. Water samples
taken near the sediment surface contained a higher percentage of
soluble phosphorus than water samples taken at greater distances
from the sediment surface.
The establishment of an upper oxidized layer and lower reduced
layer may be expected in sediments left undisturbed for appreciable
periods of time, but sediments covered by shallow waters and sub-
4. Unpublished data.
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CHAPTER 2 / CHEMISTRY OF SEDIMENT / 31
jected to wave action may not exhibit the same characteristics.
Stephenson (1949) found that agitation of sea water with bottom
mud may either increase or decrease the concentration of phosphate
in solution. The changes in phosphate levels are ascribed to (1)
destruction of organisms with release of protoplasm, (2) breakdown
of this protoplasm by bacteria with release of phosphate, and (3)
absorption of phosphate by bacteria.
Certain benthic ciliates are capable of splitting inorganic phos-
phorus from dilute solutions of organic phosphates that occur in
lake sediments (Hooper and Elliott, 1953). This process may provide
a source of energy supplementary to that obtained from ingestion
of participate organic matter and bacteria, but its importance in
nutrition is unclear.
Sediment plays an important role in the assimilation of phos-
phate during transport in waters. Keup (1968) has quoted Gessner
(1960) on studies of the turbid Amazon River that indicate when
soluble phosphorus concentrations exceed 0.01 ppm, it is sorbed on
finely divided inorganic suspended material.
Obviously, bottom sediments can remove relatively large
amounts of dissolved phosphate from waters but the partition of
this removal is not well understood. It is probable that these sedi-
ments act as a control, removing phosphate from the water when
the concentration is above the equilibrium value and releasing phos-
phate to the water when the concentration falls below the equilibrium
point. The contribution that these sediments make to support algal
growth is not known, but without thermal or mechanical mixing it
is doubtful that sufficient phosphate could diffuse at a rate fast
enough to support algae more than a few inches from the sediment.
SUMMARY
Sediment can be considered a major pollutant of surface waters.
However, its contribution to the dissolved chemicals in lakes and
streams is largely unknown. The composition of sediment closely
resembles the soil from which it is derived but is generally higher
in silt, clay, and organic matter.
Chemical reactions involving sediment are essentially the sur-
face chemistry of their colloidal fractions which is a function of
their surface area and electrical charge. As a result, reactions with
sediment can be divided into interactions with charged ions and with
neutral compounds. Cation exchange, an example of the former,
can play an important role in the uptake and release of elements
from sediments. Adsorption of anions such as phosphates is also
of great interest with respect to the fate of nutrients in natural
waters. Similarly, the adsorption of neutral polar molecules in-
fluences the chemical composition of the surface water supplies and
may have distinctly beneficial effects.
The chemistry of sediments in situ can be surmised from studies
of submerged soils. An oxidized zone exists at the soil-water interface
and a reduced zone is established beneath the oxidized zone. Nitrogen
-------
32 / PART 1 / SEDIMENT AS A WATER POLLUTANT
transformations that occur in these two zones may be postulated to
explain the inefficiency of nitrogen utilization in submerged culture.
Also, an effective mechanism for controlling the percolation of ni-
trates into groundwater supplies becomes operative when these zones
are established. The existence of anaerobic conditions in the sedi-
ment may increase the availability of phosphorus above that antic-
ipated under aerobic conditions.
Sediments carry relatively large amounts of total nitrogen and
phosphorus into surface waters, but in both cases only a small
proportion of this total is readily available to the biosystem. Sedi-
ments apparently have a high capacity to remove phosphate from
solution, but without turbulence the release of phosphate from bot-
tom sediments will not support algal growth at appreciable distances
from the sediment. However, if the concentration of phosphorus
in the surrounding solution drops low enough, the sediments will
release phosphorus. Nitrogen may be added to or removed from
the biosystem by nitrification or denitrification in the bottom sedi-
ments. Thus, it appears that sediments have a leveling influence
on nitrogen and phosphorus concentrations in surface waters.
Available inorganic nutrients, particularly phosphorus, are rap-
idly taken up by the biosystem in natural waters. They eventually
become a part of the organic fraction of the sediment and their
release back to the waters is not well resolved.
REFERENCES
Barrows, H. L., and Kilmer, V. J. 1963. Plant nutrient losses from
1 soils by water erosion. Advan. Agron. 15:303—16.
Bartholomew, R. P. 1931. Changes in the availability of phosphorus
in irrigated rice soils. Soil Sci. 31:209-18.
Bremner, J. M., and Shaw, K. 1958a. Denitrification in soil. I.
Methods of investigation. /. Agr. Sci. 51:22-39.
. 1958b. Denitrification in soil. II. Factors affecting denitrifica-
tion. J. Agr. Sci. 51:40-52.
Broadbent, F. E., and Stojanovic, B. F. 1952. The effect of partial
pressure of oxygen on some soil nitrogen transformations. Soil
Sci. Soc. Am. Proc. 16:359-63.
Chao, T. T., Harward, M. E., and Fang, S. C. 1965. Exchange reac-
tions between hydroxyl and sulfate ions in soil. Soil Sci.
99:104-8.
Chave, K. E. 1965. Carbonates: association with organic matter in
surface seawater. Science 148:1723-24.
Clapp, C. E., Olness, A. E., and Hoffmann, D. J. 1968. Adsorption
studies of a dextran on montmorillonite. Trans. 9th Intern.
Congr. Soil Sci. 1:627-34.
Coleman, N. T., Craig, D., and Lewis, R. J. 1963. Ion-exchange reac-
tions of cesium. Soil Sci. Soc. Am. Proc. 27:287-89.
Connell, W. E., and Patrick, W. H., Jr. 1968. Sulfate reduction in
soil: effects of redox potential and pH. Science 159:86-87.
Frink, C. R. 1969. Chemical and mineralogical characteristics of
eutrophic lake sediments. Soil Sci. Soc. Am. Proc. 33:369-72.
-------
CHAPTER 2 / CHEMISTRY OF SEDIMENT / 33
Gessner, F. 1960. Investigations of the phosphate economy of the
Amazon. Intern. Rev. Hydrobiol. 45:339-45.
Gorham, E. 1958. Observations on the formation and breakdown
of the oxidized microzone at the mud surface in lakes. Limnol.
Oceanog. 3:291-98.
Greenland, D. J. 1963. Adsorption of polyvinyl alcohols by mont-
moriUonite. /. Colloid Sci. 18:647-64.
. 1965. Interaction between clays and organic compounds in
soils. I. Mechanisms of interaction between clays and defined
organic compounds. Soils Fertilizers 28:415-25.
Grim, R. E. 1968. Clay mineralogy. New York: McGraw-Hill.
Harter, R. D. 1968. Adsorption of phosphorus by lake sediments.
Soil Sci. Soc. Am. Proc. 32:514-18.
Hasler, A. D. 1957. Natural and artificially (air-plowing) induced
movement of radioactive phosphorus from the muds of lakes.
Intern. Conf. Radioisotopes in Scientific Res., UNESCO/NS/
RIC/188 (Paris) 4:1-16.
Hayes, F. R., McCarter, J. A., Cameron, M. L., and Livingstone, D. A.
1952. On the kinetics of phosphorus exchange in lakes. /.
Ecol. 40:202-16.
Hoffmann, R. W., and Brindley, G. W. 1960. Adsorption of non-ionic
aliphatic molecules from aqueous solutions on montmorillonite.
Geochim. Cosmochim. Acta 20:15—29.
Holden, A. V. 1961. The removal of dissolved phosphate from lake
waters by bottom deposits. Verhandl. Intern. Ver. Limnol.
35:247-51.
Hooper, F. F., and Elliott, A. M. 1953. Release of inorganic phos-
phorus from extracts of lake mud by protozoa. Trans. Am.
Microscop. Soc. 72:276-81.
Keup, L. E. 1968. Phosphorus in flowing waters. Water Res. (Great
1 Britain) 2:373-86.
Lee, G. F., and Hoadley, A. W. 1967. Biological activity in relation
to the chemical equilibrium composition of natural waters.
Ad-van. Chem. Ser. 67:319-39.
Lomenick, T. F., and Tamura, T. 1965. Naturally occurring fixation
of cesium-137 on sediments of locus trine origin. Soil Sci. Soc.
Am. Proc. 29:383-87.
Lotse, E. G., Graetz, D. A., Chesters, G., Lee, G. B., and Newland,
L. W. 1968. Lindane adsorption by lake sediments. Environ.
Sci. Technol. 2:353-57.
Massey, H. F., and Jackson, M. L. 1952. Selective erosion of soil
fertility constituents. Soil Sci. Soc. Am. Proc. 16:353-56.
Massey, H. F., Jackson, M. L., and Hays, O. E. 1953. Fertility ero-
sion on two Wisconsin soils. Agron. J. 45:543—47.
Mitsui, S. 1954. Inorganic nutrition, fertilization, and soil ameliora-
tion for loivland rice. Tokoyo: Yokendo.
Mortimer, C. H. 1942. The exchange of dissolved substances be-
tween mud and water in lakes. J. Ecol. 30:147-201.
Patrick, W. H., Jr. 1960. Nitrate reduction rates in a submerged
soil as affected by redox potential. Trans. 7th Intern. Congr.
Soil Sci. 2:494-500.
. 1964. Extractable iron and phosphorus in a submerged soil
at controlled redox potentials. Proc. 8th Intern. Congr. Soil Sci.
Bucharest, Roumania 4:605-10.
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34 / PART 1 / SEDIMENT AS A WATER POLLUTANT
Patrick, W. H., Jr., and Mahapatra, I. C. 1968. Nitrogen and phos-
phorus in waterlogged soils. Advan. Agron. 20:323-59.
Paul, H., and DeLong, W. H. 1949. Phosphorus studies. I. Effects
of flooding on soil phosphorus. Sci. Agr. 29:137-47.
Pomroy, L. R., Smith, E. E., and Grant, Carol M. 1965. The ex-
change of phosphate between estuarine water and sediments.
Limnol. Oceanog. 10:167-72.
Rich, C. I. 1968. Applications of soil mineralogy in soil chemistry
and fertility investigations in mineralogy in soil science and
engineering. Soil Sci. Soc. Am. Spec. Publ. 3, pp. 61—90
Rigler, ±*'. H. 1956. A tracer study of the phosphorus cycle in lake
water. Ecology 37:550-62.
Sawhney, B. C. 1964. Sorption and fixation of micro-quantities of
cesium by clay minerals: effect of saturating cations. Soil Sci.
Soc. Am. Proc. 28:183-86.
Sawyer, C. N., Lackey, J. B., and Lenz, A. T. 1944. Investigation
of the odor nuisance occurring in the Madison lakes, particularly
Lakes Monona, Waubesa, and Kegonsa from July 1943 to
July 1944. Report to the Governor's Committee, State of Wis-
consin.
Schofield, R. K., and Sampson, H. R. 1954. Flocculation of kaolinite
due to the attraction of oppositely charged crystal faces. Dzs-
cussions Faraday Soc. 18:135.
Shapiro, R. E. 1958. Effect of organic matter and flooding on avail-
ability of soil and synthetic phosphates. Soil Sci. 85:267—72.
Stall, J. B. 1964. Sediment movement and deposition patterns in
Illinois impounding reservoirs. /. Am. Water Works Assoc.
56:755-66.
Stephenson, W. 1949. Certain effects of agitation upon the release
, of phosphate from mud. /. Marine Biol. Assoc. 28:371-80.
Tenny, F. G., and Waksman, S. A. 1930. Composition of natural
organic materials and their decomposition in the soil. V. De-
composition of various chemical constituents in plant materials,
iinrior -i-~erobjc conditions. Soil Sc.i. 30:143-6°.
Theabold, P. K., Jr., Lakin, H. W., and Hawkins, D. B. 1963. The
precipitation of aluminum, iron and manganese at the junction
of Deer Creek with the Snake River in Summit County, Colorado.
Geochim. Cosmochim. Acta 27:121—32.
Turner, F. T., and Patrick, W. H., Jr. 1968. Chemical changes in
waterlogged soils as a result of oxygen depletion. Proc. 9th
Intern. Congr. Soil Sci. Australia 4:53—65.
Waring, S. A., and Bremner, J. M. 1964a. Ammonium production
in soil under waterlogged conditions as an index of nitrogen
availability. Nature 201:951-52.
. 1964b. Effect of soil mesh-size on the estimation of mineral-
izable nitrogen in soils. Nature 202:1141.
Zicher, E. L., Berger, K. C., and Hosier. A. D. 1956. Phosnhorus
release from bog lake muds. Limnol. Oceanog. 1:296-303.
-------
CHAPTER THREE,.
LAND AND WATER MANAGEMENT
FOR MINIMIZING SEDIMENT
MINORU AMEMIYA
PEDIMENTS are primarily soil particles washed into streams by
water. They are products of land erosion and are largely derived
from sheet and rill erosion from upland areas, and by cyclic erosion
activity in gullies and drainageways. It is estimated (Wadleigh, 1968)
that at least half of the 4 billion tons of sediment washed annually
into tributary streams in the United States is coming from agricul-
tural lands.
Erosion can be natural or can be accelerated by man's activities.
Natural or geologic erosion pertains to that occurring under natural
environmental conditions. Man-made or accelerated erosion is that
induced by man through reduction of natural vegetative cover and
improper land use, and occurs at a rate greater than normal for the
site under natural cover.
Although sediment yield and soil erosion are not synonymous,
they are closely related—and occasionally used interchangeably.
Sediment yield can be denned as the quantity of soil material trans-
ported into a stream. Soil erosion refers to detachment and move-
ment of soil particles on site, but does not imply movement into
stream channels. Thus, soil erosion is a primary requisite for sedi-
ment production. The most logical and direct approach to solving
our agriculturally related sediment problem is the stabilization of the
sediment source by controlling soil erosion through the use of proper
land and water management practices or structures. In short, to
minimize sediment yield, soil erosion must be minimized.
Soil erosion occurs in two basic steps (Smith and Wischmeier,
1962): (1) detachment of soil particles from adjacent particles by
raindrop impact and splash, and (2) transport of detached particles
by flowing water. Only when conditions for these steps exist does
soil erosion become a serious problem as a direct source of sediment.
Soil erosion by water is a physical process requiring energy, and its
control involves the dissipation of energy—that of falling raindrop
impact and splash, and that due to elevation differences which affect
the flow velocity of water.
MINORU AMEMIYA is Associate Professor and Extension Agronomist,
Department of Agronomy, Iowa State University.
35
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36 / PART 1 / SEDIMENT AS A WATER POLLUTANT
The present state of knowledge concerning the mechanics and
hydrology of soil detachment and transport have already been ade-
quately reviewed (see Chapter 1). The properties of sediments from
agricultural lands have been described and interpreted (see Chapter
2). It is the purpose of this chapter to briefly review management
practices for controlling soil erosion to minimize consequent sediment
production from agricultural lands. Emphasis will be on sediments
derived from sheet-rill or microchannel erosion. This does not imply
that sediments resulting from gully or macrochannel erosion are not
serious contributors to total sediment yield. However, it has been
shown that the best method of controlling gully erosion is to minimize
runoff and sheet erosion above a gully or potential gully site (Jacob-
son, 1965).
FACTORS AFFECTING SOIL EROSION BY WATER
The Universal Soil Loss Equation (Smith and Wischmeier, 1962)
provides a framework for discussing erosion control measures. In
this equation, soil erosion is described as a function of rainfall, soil
properties, slope length and steepness, cropping sequence, and sup-
porting practices.
At present, little can be done to readily change the amount, distri-
bution, and intensity of rainfall per se, but measures can be adopted
to modify its erosiveness—that is, to decrease raindrop impact and
splash energy or to decrease the amount and velocity of overland
flow, or both—to minimize sediment production.
Soil properties affect both detachment and transport processes.
Detachment is related to soil stability, size, shape, composition, and
strength of soil aggregates and clods. Transport is influenced by
permeability of soil to water which determines infiltration capabili-
ties and drainage characteristics, aggregate stability which influences
crusting tendencies, porosity which affects storage and movement of
water, and soil macro-structure or surface roughness which creates a
potential for temporary detention of water.
The slope factor determines the transport portion of the erosion
process since flow velocity is a function of hydraulic gradient which
is influenced by slope length and steepness. The remaining two
factors, cropping sequence and supporting practices, serve to modify
either the soil factor or the slope factor or both, as they affect the ero-
sion sequence.
Water runoff and accompanying soil erosion resulting from
rainstorms are inversely related to the water infiltration capacity of
soil, plus any surface storage capacity. Hence, one way to prevent
erosion would be to maintain high water intake rates and surface
ponding capacities at levels sufficient to prevent runoff from all rain-
storms (Meyer and Mannering, 1968). This is seldom possible, but
any increase in infiltration capacity and surface and subsurface
storage capacity can greatly reduce erosion as well as benefit crop
water supply. In most cases water intake and storage capacities are
not sufficient to prevent runoff. Soil erosion then becomes a func-
-------
CHAPTER 3 / MINIMIZING SEDIMENT / 37
TABLE 3.1. Effect of rotes of applied wheat straw mulch on runoff, infiltra-
tion, and soil loss from Wea silt loam with 5% slops.
Mulch
Rate
(tons/ a)
0
V4
V2
1
2
4
Surface
Cover
(%)
0
40
60
87
98
100
Water
Applied*
Cinches)
6.25
6.25
6.25
6.25
6.25
6.25
Runoff
(inches)
2.83
2.50
1.58
0.30
0.09
0.00
Infiltration
(inches)
3.42
3.75
4.67
5.95
6.16
6.25
Soil Loss
(tons/a)
12.42
3.23
1.42
0.30
0.00
0.00
Source: Adapted from Mannering and Meyer (1963).
* Water applied at constant intensity of 2.5 inches per hour.
tion of runoff velocity and the resistance of the soil to the forces of
flowing water.
Laboratory studies have shown that the amount of energy re-
quired to initiate runoff was a function of clod size (Moldenhauer and
Kemper, 1969). Rough, cloddy surfaces enhanced water intake and
contributed to surface detention of water, even after water intake
was reduced by pore sealing. It was apparent that large clods created
many steep micro-slopes. Dispersed particles from soil peaks eroded
into depressions, leaving exposed areas still receptive to water.
A vegetative cover or surface mulch is one of the most effective
means of controlling runoff and erosion (Duley and Miller, 1923;
Borst and Woodburn, 1942; Baver, 1956; McCalla and Army, 1961;
Smith and Wischmeier, 1962). Wheat straw mulch applied on
freshly plowed land at a rate exceeding one ton per acre almost com-
pletely eliminated runoff from, and controlled erosion on, a 5% slope,
as shown in Table 3.1 (Mannering and Meyer, 1963). Mulch on the
surface protected it from raindrop impact energy, reducing detach-
ment of soil particles and surface sealing. In so doing, high water
intake rates were maintained. The effectiveness of mulch in main-
taining high intake rates was correlated with the proportion of the
surface covered. In addition, the mulch created barriers and ob-
structions that apparently reduced flow velocity and carrying capacity
of runoff. This was evident especially at the '/r and i/o-ton mulch
applications where total runoff was 87 and 56% , respectively, of the
zero mulch treatment. In contrast, soil loss was 27 and 11% , respec-
tively, of the zero rate.
In another study (Meyer and Mannering, 1968), runoff velocity
was measured as a function of mulch rate. Five inches of simulated
rain were applied at a constant intensity of 2.5 inches per hour to
soil treated with straw mulch at various rates. Data shown in Table
3.2 indicate that small amounts of surface mulch caused considerable
reduction in flow velocity. Moreover, large reductions in erosion rates
were associated with relatively small reductions in flow velocity. This
was not unexpected because the quantity of material moved is con-
sidered proportional to about the fourth power of velocity.
In a laboratory study, Kramer and Meyer (1968) studied the effects
-------
38 / PART 1 / SEDIMENT AS A WATER POUUTANT
TABLE 3.2. Effect of applied wheat straw mulch on run-
off velocity, and soil loss from Wea silt loam
with 5% slope.
Mulch
Rate
(tons/a)
0
V4
Vz
1
Runoff
(inches)
3.3
2.8
2.4
2.0
Runoff
Velocity*
(ftfmin)
26
14
12
7
Soil Loss
(tons/a)
14.5
5.8
3.7
1.7
Source: Adapted from Meyer and Mannering (1968).
* After application of about 5 inches of rainfall when
runoff rates were essentially constant.
of mulch rate, slope steepness, and slope length on soil loss and run-
off velocity. Using a glass bead bed to simulate a soil slope, they
showed that less than a ton of mulch on the surface reduced erosion
on slopes greater than 70 feet long at 4% slope. Mulch rates of less
than 1 ton reduced erosion from moderate to steep slopes (4 to 6%).
However, on slopes of 8 and 10% , J/s- and i/^-ton mulch rates did not
greatly decrease erosion compared to no mulch. Erosion more than
doubled as slopes increased from 8 to 10%. Again, mulch rates
]/i ton or greater reduced runoff velocity considerably. It was noted
that for some conditions low mulch rates increased erosion as com-
pared to no mulch. This was attributed to increased flow velocity
and turbulence around mulch pieces, causing particle movement.
In some area soil wettability is considered a factor in soil
credibility. Water repellency, often developed as a result of fires on
some soils, can cause much sediment production by curtailing infil-
tration and encouraging runoff. Reduction in erosion is effected by
modifying the wetting characteristics of hydrophobic soil. By me-
chanical or chemical means, soil wettability can be increased so that
infiltration rate is increased (Osborn and Pelishek, 1964; De Bano,
1969).
Another means of preventing runoff and increasing total infil-
tration is through surface storage. Rough soil surfaces can retain
several more inches of rainfall than smooth surfaces, due to water
being trapped in the depressions of the rough topography (Larson,
1964). Available subsurface storage capacity has also been recog-
nized (Holtan, 1965) to be important in the infiltration process. Thus,
for soils to have high infiltration capabilities, they must have a high
inherent permeability to water, show resistance to crusting, and have
a high surface and subsurface storage capacity.
PRACTICES FOR EROSION CONTROL
Practices or structures for erosion control are designed to do one
or more of the following: (1) dissipate raindrop impact forces, (2)
reduce quantity of runoff, (3) reduce runoff velocity, and (4) manipu-
late soils to enhance the resistance to erosion (Meyer and Mannering,
1968).
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CHAPTER 3 / MINIMIZING SEDIMENT / 39
ULLAGE METHODS AND SROSJON CONTROL
The relationship between tiDage methods and soil erosion has
been reported by many investigators. Principles involved have been
well documented (Larson, 1964; Mannering and Burwell, 1968).
Some tillage methods deter soil erosion by creating rough surfaces
which provide surface storage, reduce runoff, and delay or prevent
surface crusting. Other tillage methods provide increased subsurface
storage, and still others provide both. There are tillage methods that
leave all or part of the residue from previous crops on or near the soil
surface, protecting the surface from raindrop forces and enhancing
water infiltration. Excessive tillage can be a factor in soil erosion,
however, because tillage is a source of energy for breaking soil into
erodible sizes just as are rainfall and runoff. Tillage-induced soil con-
ditions play a significant role in soil erosion through effects on the
infiltration capabilities of soil (Burwell et al, 1966; Burwell et al.
1968).
On a silt loam soil, 6.7 inches of simulated rainfall, applied at a
constant intensity of 5 inches per hour, infiltrated a surface created
by moldboard plowing before runoff began. When the soil was
plowed, disked, and harrowed, only 2.1 inches of water infiltrated be-
fore initiation of runoff. Comparable values for unfilled and rotary
tilled soil were 0.4 and 0.9 inch, respectively. Cumulative water in-
take was fifteen times greater on rough, plowed soil and three times
greater on plowed, disked, and harrowed soil than on untilled soil.
These differences were related to plow layer porosity and to surface
roughness (Burwell et al., 1966).
Another study conducted on the same soil compared infiltration
of simulated rainfall of mulch-tilled and clean-tilled surfaces (Bur-
well et al., 1968). The soil was previously cropped to oats. Mulch
tillage consisted of a pass with a chisel-type cultivator to a depth of 6
inches. This tillage operation incorporated about half of the oat
stubble residue, leaving about 0.6 ton per acre on the surface. Clean
tillage consisted of moldboard plowing in the fall, with and without
secondary disking and harrowing the following spring, and spring
plowing alone. Table 3.3 is a summary of this study. Fall mulch-
tilled surfaces provided nearly eight times greater infiltration capacity
TABLE 3.3 Influence of tillage treatment on water infiltra-
tion.
Tillage Infiltration
Fall
Chisel
Plow
Plow
None
Spring
None
None
Disk, harrow
Plow
To initial
runoff
(inches)
6.7
1.2
0.9
2.1
During 2"
runoff
(inches)
3.8
1.6
0.8
1.5
Source: Adapted from Burwell. Stoneker, and Nelson
(1968).
-------
40 / PART 1 / SEDIMENT AS A WATER POLLUTANT
before runoff started and four times greater infiltration capacity dur-
ing runoff than did fall-plowed surfaces, disked and harrowed in the
spring. Infiltration for fall mulch-tilled surfaces was more than
three times greater than for spring-plowed surfaces. Fall-plowed sur-
faces were altered by fall to spring weathering, resulting in little, if
any, infiltration advantage over fall-plowed, spring-disked, and
harrowed surfaces. Rainfall action, wetting-drying, and freezing-
thawing cycles between fall plowing and spring planting act to dis-
perse soil material which seals the surfaces by filling in depressions
and open channels created by plowing.
These representative data indicate that the amount of water
entering soil can be controlled significantly by soil physical condi-
tions created by tillage operations. Conventional tillage (plow, disk,
harrow) usually creates conditions that restrict water movement.
Mulch and other so-called minimum tillage systems can produce soil
conditions conducive to water intake. Plowing, followed by disking
and harrowing, usually leaves the soil clean or void of crop residue.
Rain falling on these bare or only partially covered surfaces washes
fine soil into depressions and open channels, resulting in progressive
soil sealing. Rate of sealing depends on how cloddy or how rough
the surface is after tillage. Where clean tillage is practiced, it should
create rough, cloddy surfaces that resist dispersion and subsequent
surface sealing so as to delay the first runoff event during the spring.
In a recent summary (Burwell and Larson, 1969) it was shown
that prior to initial runoff, tillage-induced roughness accounted for
most of the variation in infiltration, whereas differences in pore space
caused only minor variations. In contrast, during a 2-inch runoff
period, water intake was little affected by roughness or porosity—
indicating that surface seals were already formed when runoff started,
and overshadowed roughness or porosity changes induced by tillage.
Mulch tillage—a tillage system that loosens the soil without
soil inversion—leaves all or most crop residue on the soil surface.
This creates a condition highly resistant to raindrop and runoff forces.
A comparison of runoff and soil loss from conventional and mulch
tillage is typified in Table 3.4. In each instance the benefits of this
type of tillage are apparent.
Deep tillage or subsoiling of some soils can reduce soil losses by
increasing volume of subsurface storage available for infiltrated
water. If deep tillage shatters or fractures a soil pan, this increased
storage may be much greater than indicated by the increased depth
of tillage. However, subsoiling generally has not been effective unless
channels were kept open to the soil surface. If subsequent tillage
obliterates subsoiler slots in the surface few inches, little difference
in soil loss or infiltration can be expected (Meyer and Mannering,
1968).
Postplanting tillage is used with most tillage systems. If a sur-
face seal has developed, cultivation to break it may materially in-
crease water intake. In a 5-year tillage study (Mannering et al., 1966),
cultivation of minimum tilled treatments reduced average runoff
from 3.5 to 2.1 inches and soil loss from 16.3 to 9.5 tons per acre as
compared to the same treatments uncultivated. Under some condi-
-------
CHAPTER 3 / MINIMIZING SEDIMENT / 41
TABLE 3.4. EfFect of mulch tillage on runoff and soil losses in the Corn Belt.
Location,
Soil, and Slope
Field
Practice
Tillage
Runoff
Soil
Loss
Wisconsin
Miami si, 6%
Miami si, 9%
Fayette si, 16%
Ohio
Muskingum si,
9-15%
Indiana
Russell si, 5%
(inches) (tons/a)
Noncontoured Conventional
Mulch
Contoured Conventional
Mulch
Conventional
Contoured
Contoured
Mulch
Conventional
Mulch
Noncontoured Minimum
Mulch
3.1
2.5
0.8
0.06
0.6
0.05
1.14
0.05
3.12
2.24
22.3
6.7
1.4
0.01
2.0
0.03
7.8
0.03
10.7
0.5
Source: Adapted from Mannering and Burwell (1968).
tions, cultivation of rough, cloddy surfaces may increase credibility
by decreasing soil aggregate size, decreasing surface roughness, and
reducing existing crop residue surface cover.
SLOPE MODIFICATION FOR EROSION CONTROL
Contour planting and tillage function to control runoff and soil
loss from storms that are moderate in extent, or until capacity of soil
to hold or to conduct runoff is exceeded. In field practice, rows are
oriented on the contour, generally with a slight grade toward a water-
way. On slopes of moderate steepness and length, average annual
soil loss can be reduced by about 50% (Smith and Wischmeier, 1962).
Runoff is ponded and flows slowly around the slope rather than down-
slope. However, when smooth tillage is used, or when infiltration
rates are low, runoff from high intensity rains may overtop rows, re-
ducing runoff and erosion effectiveness. In addition, because con-
touring generally results in point rows and irregular field shapes, its
use as an erosion control practice is declining. Large farming equip-
ment and narrow rows are not compatible with point row farming.
Contour strip-cropping is the practice of alternating strips of a
close-growing meadow or grass crop with strips of grain or row crops
across a hillside. The erosion control aspect of strip-cropping is the
reduction in length of slope of land in row crop. In addition, flow
velocity of runoff water is reduced as it moves through the close-
growing grass strip, causing sediments to drop out. The sod literally
acts as a filter strip. The reduction in soil erosion from a strip-cropped
slope is proportional to the fraction of the slope that is in grass strips
(Wischmeier and Smith, 1965).
Terracing is one of the oldest practices used to control erosion.
Terraces are combinations of ridges and channels laid out across the
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42 / PART 1 / SEDIMENT AS A WATER POLLUTANT
slope to trap water running downslope, and to conduct the water to
suitable surface or subsurface outlets at a nonerosive velocity. The
primary benefit of terracing is the reduction in slope length. Since
erosion is approximately proportional to the square root of slope
length (Smith and Wischmeier, 1962), reducing slope length in half
can reduce erosion by more than 20% . Bench-type terraces also pro-
vide for a reduction in slope steepness. Terracing with contour farm-
ing is generally considered more effective as an erosion control prac-
tice than strip-cropping, but it is also more expensive. With both
practices soil loss is confined within field boundaries. In strip-
cropping the saved soil from one storm event is deposited in the sod
strip and can be transported further downslope during subsequent
storms. With terracing, the deposition is in the terrace channel which
offers positive sediment retention, unless overtopping occurs.
Although effective for erosion control, conventional broad-based
terrace systems are not compatible with efficient tillage operations or
modern farm equipment. In addition, herbicides are making it in-
creasingly difficult to maintain grassed waterways. To overcome
these problems, a system of bench terraces with permanently vege-
tated backslopes is gaining popularity (Jacobson, 1966). In this
system, all runoff is collected in low spots in the terrace channel and
if necessary removed through underground tile outlets, thus grassed
waterways. Parallel terraces materially straighten field alignment
and eliminate objectionable point rows. In time sediment deposited in
the channel reduces the slope in the terrace intervals.
Studies on instrumented watersheds in western Iowa on deep
loess soil indicate that although terracing did not affect total water
yield from a watershed, the surface flow component of water yield
was significantly reduced. Only 14% of water yield from terraced
watersheds was surface flow, while on unterraced but contour-farmed
watersheds, surface flow accounted for 64% of water yield (Saxton
and Sportier, 1968). These differences in surface flow were associated
to sediment yield from these watersheds as shown in Table 3.5
(Piest and Spomer, 1968).
OUTLOOK
Slope modification measures combined with soil-conserving
tillage practices can be effective in reducing soil erosion from cropped
land. However, to become widely accepted, such practices must fit
efficient farming operations and must be economically feasible. If
presently available practices do not meet these requirements, new
practices or systems that will control erosion and sediment produc-
tion without loss of net income to the operator must be developed.
For example, consider a system where sheet erosion is controlled
through till-plant tillage, and runoff is controlled by storage fills con-
structed across waterways (Jacobson, 1969). The fills, like bench
terraces, would have favorable uphill slopes with a seeded backslope.
Water would be removed from fills by tile outlets. It is anticipated
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CHAPTER 3 / MINIMIZING SEDIMENT / 43
TABLi 3.5. Effect of land treatment on sediment yield of watersheds in
western Iowa.
Sediment Yield
Watershed Size Crop Land Treatment 1964 1985 1966
1
2
3
4
(acres)
75
83
107
150
(tons/a)
Cont.
Cont.
Grass
Cont.
corn
corn
corn
Field
Field
None
Level
contoured
contoured
terraced
30
30
2
2
60
45
2
2
8
10
1
1
Source: Adapted from Piest and Spomer (1968).
that such a system would almost eliminate soil loss from cropped
fields on slopes up to 6%. Soil-moved sheet erosion is stored in the
fills and eventually helps reduce slopes. Again, troublesome hillside
waterways are eliminated. Straight row farming is possible, adding to
farm adaptability. And the cost of such a system should be relatively
low. Tillage costs will be lower, and building the system of storage
fills often would be less costly than building waterways. On lands
with slopes steeper than 6% , farming becomes progressively difficult.
Unless the slope can be reduced to permit more efficient machinery
operation, economics will force the retirement of much of these lands
from row-cropping (Jacobson, 1969). Erosion control on such land
will require bench terraces with tile outlets.
To reiterate, nearly all sediment is the result of man's removal
or disturbance of natural soil cover of trees and grass. Since all land
cannot be returned to its original cover, wise land use planning and
careful use and treatment of land can reduce soil erosion, the source
of sediment. Although the mechanics of the erosion process are not
completely understood, guidelines have been developed, satisfactorily
tested, and translated into erosion control practices, measures, and
structures. Existing erosion control technology has not been univer-
sally accepted and used, primarily because of direct or indirect
economic considerations (Swanson and MacCallum, 1969). The chal-
lenge to agriculturists, conservationists, engineers, and economists is
to continue their efforts to develop an improved erosion control tech-
nology that will be compatible with modern requirements and eco-
nomically feasible. Only when this challenge is met will there be a
significant reduction in sediments redrived from agricultural lands.
REFERENCES
Baver L. D. 1956. Soil phijsics. 3rd ed. New York: John Wiley.
Borst,'H. L., and Woodburn, R. 1942. Effect of mulches and surface
conditions on the water relations and erosion of Mulkingum
soil. USDA Tech. Bull. 825.
Burwell, R. E., and Larson, W. E. 1969. Infiltration as influenced by
tillage-induced random roughness and pore space. Soil ScL Soc.
Am. Proc. 33:449-52.
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44 / PART 1 / SEDIMENT AS A WATER POLLUTANT
Burwell, R. E., Allmaras, R. R., and Sloneker, L. L. 1966. Structural
alteration of soil surfaces by tillage and rainfall. J. Soil Water
Conserv. 21:61-63.
Burwell, R. E., Sloneker, L. L., and Nelson, W. W. 1968. Tillage in-
fluences water intake. /. Soil Water Conserv. 23:185-88.
De Bano, L. F. 1969. Water repellent soils. Agr. Sci. Rev. 7(2): 11-
18.
Duley, F. L. 1939. Surf ace factors affecting rate of intake of water by
soils. Soil Sci. Soc. Am. Proc. 4:60-64.
Duley, F. L., and Miller, M. F. 1923. Erosion and surface runoff un-
der different soil conditions. Mo. Agr. Exp. Res. Sta. Bull. 63.
Ellison, W. D. 1947. Erosion studies, Parts I, II, and III. Agr. Eng.
28:145-46, 197-201, 245-48.
Holtan, H. N. 1965. A model for computing watershed retention
from soil parameters. /. Soil Water Conserv. 20:91-94.
Jacobson, P. 1965. Gully control in Iowa. In Proc. Fed. Inter-agency
Sedimentation Conf. 1963, pp 111-14. USDA Misc. Publ. 970.'
. 1966. New developments in land terrace systems. Am. Soc.
Agr. Engrs. Trans. 9:576-77.
1969. Soil erosion control practices in perspective. J. Soil
Water Conserv. 24:123-26.
Kramer, L. A., and Meyer, L. D. 1968. Small amounts of surface
mulch reduce erosion and runoff velocity. Paper 68—206 pre-
sented at meeting of Am. Soc. Agr. Engrs., 18-21 June 1968,
Logan, Utah.
Larson, W. E. 1964. Soil parameters for evaluating tillage needs and
operations. Soil Sci. Soc. Am.Proc. 28:119-22.
McCalia, T. M., and Army, T. J. 1961. Stubble mulch farming.
Advan. Agron. 13:125-97.
Mannering, J. V., and Burwell, R. E. 1968. Tillage methods to re-
duce runoff and erosion in the Corn Belt. USDA Information
Bull. 330.
Mannering, J. V., and Meyer, L. D. 1963. Effects of various rates of
surface mulch on infiltration and erosion. Soil Sci. Soc. Am.
Proc. 27:84-86.
Mannering, J. V., Meyer, L. D., and Johnson, C. B. 1966. Infiltra-
tion and erosion as affected by minimum tillage for corn (Zea
mays L.). Soil Sci. Soc. Am. Proc. 30:101-4.
Meyer, L. D., and Mannering, J. V. 1968. Tillage and land modifica-
tion for water erosion control. In Tillage for greater crop pro-
duction, pp. 58-62. St. Joseph, Mich.: Am. Soc. Agr. Engrs.
PROC-168.
Moldenhauer, W. C., and Kemper, W. D. 1969. Interdependence of
water drop energy and clod size on infiltration and clod sta-
bility. Soil Sci. Soc. Am. Proc. 33:297-301.
Osborn, J. F.. *nd Pelishek, R. E. 1964. Soil xvettability as a factor
in credibility. Soil Sci. Soc. Am. Proc. 28:294-95.
Piest, R. F., and Spomer, R. G. 1968. Sheet and gully erosion in
the Missouri Valley loessial legion. Trans. Am. Soc. Agr. Engrs.
11:850-53.
Saxton, K. E., and Spomer, R. G. 1968. Effects of conservation on
the hydrology of loessial watersheds. Trans. Am. Soc. Agr.
Engrs. 11:848, 849, 853.
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CHAPTER 3 / MINIMIZING SEDIMENT / 45
Smith, D. D., and Wischmeier, W. H. 1962. Rainfall erosion.
Advan. Agron. 14:109-48.
Swanson, E. R., and MacCallum, D. E. 1969. Income effects of
rainfall erosion. J. Soil Water Conscru. 24:56-59.
Wadleigh, C. H. 1968. Wastes in relation to agriculture and for-
estry. USDA Misc. Publ. 1065.
Wischmeier, W. H., and Smith, D. D. 1965. Predicting rainfall ero-
sion losses from cropland east of the Rocky Mountains. USDA
Agricultural Handbook 282.
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CHAPTER FOUR_
WORKSHOP SESSION
G. M. BROWNING, Leader
H. G. HEINEMANN, Reporter
Browning: There are four or five things that we want to do.
We should consider what is known about soil as a pollutant. A
good bit of that evidence was discussed at the session yesterday
morning. We should also consider where we are now and what we
know—and what additional knowledge we need to get to where we
want to be in the next 5 to 10 years. A workshop such as this is
an excellent way to identify and get a consensus of what the im-
portant problems are and to learn how we might do something
about them.
Verduin: I think the whole picture is really long term—very
encouraging, from what I have heard since I got here. Amemiya's
paper shows that if you have farmland so good that you want to
farm it but it has too much slope, you can terrace it, and you won't
lose much from it—any more than you did from grassland, which
we consider pretty good soil-holding land. The whole thing, of
course, is tied to our problem of feeding the people who need food,
but we have been doing that with less and less acreage. It seems
to me that in the 20-year future, we may well have all farmland
that does not erode. We have a chance to get our erosion under con-
trol in this country and set a model for the whole world.
Browning: Does anyone want to respond to that?
Laflen: We have had erosion control practices since sometime
in the late eighteenth or nineteenth century. Our terracing pro-
gram started out fairly strongly with the USDA in the thirties, and
today we still have between 5 and 8 million acres of cropland that
needs terracing. With the independent farmer, I don't see how we
are going to get the terracing done in the near future.
Browning: I am concerned because I doubt that we are keep-
G. M. BROWNING is Regional Director, North Central Agricultural
Experiment Station Directors, Iowa State University. H. G. HEINE-
MANN is Director, North Central Watershed Research Center,
SWCRD, ARS, USDA, Columbia, Missouri.
46
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CHAPTER 4 / WORKSHOP SESSION / 47
ing up with this. On a lot of the land that is in tilled crops, with 8,
10, and even 12% slope, you can terrace and control this sediment.
But modern-day 6- to 8-row equipment doesn't fit on irregularly
shaped slopes very well. So, if we are going to any more than keep
up on those areas, we need to devise new and acceptable methods
and procedures that will help control erosion. We are not in the
ball game economically with 2- or 4-row equipment when compared
with the 6- and 8-row equipment of farmers on flatter ground. So
we have some really tough going, admitting that we know what
needs to be done and could do it. We have made a lot of progress
in the past 20 or 30 years, but we still have a whale of a long way
to go.
Herpich: I am wondering if the voracious appetites Americans
have for meat and the limited acreage on which we can put cattle
to produce it will force us to retire a lot of this poor land to the pro-
duction of crops that we could use to produce livestock. It would
probably help to solve the problem.
Browning: We all know, of course, that grass is a wonderful
conservation practice and there is a lot of land in crops that should
be growing grass if we are going to control erosion from a practical
standpoint.
Verduin: What you said is being said in a number of situations.
The pollution people are saying it. We have the technology but it
is going to be expensive. You look at the actual capacity of our so-
ciety and at the fact that the farmer, over the past 20 years, has
practically been held steady with a little bit of subsidy—and then
we say we can't subsidize him any more. Why can't we? We are
subsidizing everyone else more.
Herpich: We live on an economy of waste. You have only to
travel in some of the European countries to understand what I
mean. We have great big, wide turn rows and waste land on water-
ways. If we are really concerned with producing food, we can put
pipelines down the waterways and plant something on them.
Kerr: It bothers me that we deal so much in the ideologies of
what we are trying to do and spend so little time in how to do it.
We are talking about the sediment deposition and the ramifications
that it is going to have over a period of time—and we know that this
is very serious. But what are we going to do about it? If we take a
good look at history, we learn that the Soil Conservation Service
has accomplished some water conservation and some pollution
abatement as an incidental thing to what it is really trying to ac-
complish. Its prime objective when it was formed was to save the
soil. This needed to be done, but since then we have evolved through
a couple of steps with the Soil Conservation Service in its small
watershed program. I think most people agree that a small water-
shed program is the best tool for keeping soil and water where it
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48 / PART 1 / SEDIMENT AS A WATER POLLUTANT
is supposed to be. I can't see how we are going to accomplish sedi-
ment control for pollution purposes any more effectively than we
could with the principles of the small watershed project. So I think
that the SCS should be permitted to accept benefits accruable from
pollution abatement. It cannot do that at this time.
Cochran: I like to hear that, because in Iowa we do have the
tools. If we could get the Iowa Legislature to pass a bill, we could
do the job that everyone has been talking about. Back in 1965 I
had what turned out to be the grand opportunity of being a member
and becoming the chairman of a committee in Iowa to revise the
drainage codes, which were 50 years out of date. We began to
realize that drainage was related to flood control, soil conservation,
water pollution, recreation, and all the things that go hand in hand
with controlling soil erosion and water pollution. And so we
launched a program and developed the Ccnservacy District Bill,
which is an enlargement of the watershed program. We presented
this to the Legislature in 1969. We divided Iowa into six conservacy
districts; so, for example, we are now in the Des Moines River
Conservacy District and any water that falls on Iowa soil that even-
tually gets to the Des Moines River is in that conservacy district.
According to our Conservacy District Bill, we start in the upper
reaches of our various tributaries and begin to solve the erosion
problem on the individual pieces of land, then work downward on
the tributaries to our major streams. The farmer is responsible for
setting up soil conservation practices found in any conservation
handbook. The Conservacy District is responsible for internal im-
provements, flood control, dams, and other structures. We have set
goals to be met by voluntary action. If it is not voluntary, we will
set up rules and regulations which will have to be abided by. We
can control pollution with this method. In Iowa, we have the bill,
and now we have to convince the Legislature.
Jones: My question is: What do we need to know? We would
like to know what is a tolerable level for sediment as it moves off the
land. We have the universal soil loss equation. The Soils people tell
us that we can lose so many tons per acre per year from our soils and
still maintain production. Yet, if we look at some sedimentation
surveys of some lakes where we have public water supply and work
this information back, we will find that the lakes are accumulating
something like a quarter of a ton per acre per year from these water-
sheds, and the people are up in arms at the rate at which they are
losing their water supply from sedimentation. This quarter of a
ton per year is a far cry from the 3 to 4 tons per acre per year that
our Soils people say is a satisfactory level for controlling soil loss. So
I think we need to reevaluate what is a reasonable level of soil loss
from our fields.
Morris: I would like to address the Representative from the
Legislature about the problem of air pollution. I think it may be
wise to include an air study which is being emphasized right now
by large societies.
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CHAPTER 4 / V/ORKSHOP SESSION / 49
Cochran: In 1967 we did pass an air pollution bill set up by a
State Air Pollution Commission; however, our later bill concerns
soil erosion and water pollution from the standpoint of water and
wind erosion.
Culbertson: I was happy to hear Mr. Jones say what he did.
Very shortly we are going to have to set standards for suspended
sediment in streams. This will be extremely difficult. These rivers
have adjusted to a certain base—depending on slopes, widths, depths,
etc., and if we cut off the sediment, we will have tremendous bank
scours, bed scours, etc. Now, our problem will be to determine from
past records what the sediment supply should be in a river. We don't
want the situation that occurs below dams. So I think you have to
start in the erosion phase on the land and see what you can allow to
go into your streams and then those of us who work in the rivers (the
transport phase) will have to take it from there. Now you may have
the erosion problem solved, but we certainly do not have the transport
problem solved. And this relates to what Mr. Kerr said. If we had
some standards for sediment concentration, if it were exceeded, this
could be considered pollution or damage. Maybe this is the first step,
before including it in the damage benefit ratio.
Verduin: You mean, for example, that the clearing up of the
water in the Missouri is causing injury to all those dams because
there is not enough silt in the water?
Culbertson: Definitely. Certain types of river beds will readjust
the entire regime of the system downstream to a delicate balance
between sediment load, water discharge and velocity, and stream
width and depth.
Verduin: Yes, but before the dams the Missouri changed its
course every year. The Missouri has been doing that since the glacier
pushed down. I still think that the best silt load is as near zero as
you can get.
Culbertson: This is unnatural.
Verduin: I am not sure of that. When a country is well vege-
tated, there is not much silt in the water. The streams are clean.
I would say that the base of most of the rivers in this country is
pretty low in silt.
Herpich: From what vantage point are we defining this word
"pollution"? It seems that we must establish this before we can
say this is or is not pollutant.
Browning: What about this? Does this mean that we have
more than one goal? When the erosion factor was developed, we
had in mind what you might lose from the soil so that you could
maintain production. It seems to me that you probably have different
levels for different things you are trying to do.
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50 / PART 1 / SEDIMENT AS A WATER POLLUTANT
Kerr: I wonder if we are using what we already know. I think
we have acquired a lot of knowledge. What bothers me is that we
don't get more action. Why don't we get the tools that we need, as
Iowa is trying to with legislation?
Herpich: I can't help but feel that the action program is a little
behind the research. I think we need something positive to start to
catch up.
Morris: Some active research has already been done in which
streams have had viscosity reduction, and when that happens, there
has been a higher velocity flow, and therefore a change in stream
beds. We at the University of Nevada are making a hydrologic study
of the Trucky River system from Tahoe to Clearming Lake. I think
that things like that are necessary to make the stream behave natur-
ally over a large number of years.
Broivning: I have a letter from Roland E. Pine, Program Co-
ordinator, Water Quality and Environmental Programs, Washington
State Water Pollution Control Commission. I will just read sections
of the letter.
Irrigation of agricultural lands is the largest, single consumptive use
of water, and the resulting runoff from this activity is one of the
nation's major sources of water pollution. The Yakima and Columbia
River Basins in south-central Washington are devoted almost entirely
to agriculture and comprise one of the most extensively irrigated
regions in the nation. Nearly the entire summer flow in the lower 80
to 90 miles of the Yakima River is composed of irrigation return water.
The sediment load, and adsorbed nutrients and pesticides, is a signifi-
cant contributor to water pollution problems associated with irrigation
return flows. The control of irrigation return flows and their associated
contaminates must be through proper land and water management
practices which can and will reduce the quantity of such contaminates
carried into the receiving water.
It must be shown that such practices are highly economic practices,
beneficial to the farmer and to his neighbors with respect to crop
yield, quality of the crop and cost of production.
Lafien: The points that Pine made pertain to the failure of our
terrace practices to be accepted. It is very difficult to show to the
farm owner that conservation practices do put dollars in his pocket
within a reasonable length of time. What we need are conservation
practices that will compete for his dollar as fertilizers do.
Gattis: Economic reason has brought about more conservation
in our state than terraces have in the past 20 years. The simple
reason is that when the land was in row crops it had to be terraced.
It got to the point where you couldn't make a living on those terraced
lands, so those fields are now in pasture or in woodland. With that,
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CHAPTER 4 / WORKSHOP SESSION / 51
we have done more to reduce the sediment stream than we have in
the previous 20 years.
Shrader: On this matter of the permissible rate of erosion, I
think it is becoming increasingly clear that that is one of the basic
things. We have many fields with a loss of 20 tons per acre, because
it is in the farmer's economic interest to let that land erode. He dis-
counts the future very heavily. His idea of what is permissible soil
loss is just another magnitude different from the person that is look-
ing at the reservoir problem. We obviously need some way to use
the land that will maximize the return for the whole population for
the whole watershed.
McGill: Mr. Culbertson has raised an entirely new thought to
me. Assuming that he is correct and assuming that desirable stand-
ards could be achieved or set, what could you do about increasing
the suspension?
Culbertson: It will increase by itself. If sediment is taken from
the river and there is an unlimited supply in the stream bed and
banks, the flowing water will pick up enough sediment to bring itself
back into balance and equilibrium. We cannot stop it. The only way
you can stop this entirely is to use a TVA-type network, where the
backwater from one dam goes right up to the foot of the upstream
dam.
McGill: Seventy percent of the terrain in my part of the state
lends itself well to the growing of forage crops and pasture land.
We have done wonders and we have hardly scratched the surface in
improving our pastures. We can carry 2 to 3 head of cattle where
we have had only 1 before. In southern Iowa we would do well to
get the tax off our breeding cattle—or reduce it—and get this land
back into production of red meat. That would take care of the ero-
sion problem.
Amemiya: It has been mentioned about the detrimental effects
of decreasing the silt load in the streams, insofar as the stream
channel is concerned. And it has been alluded to that there is an
equilibrium established in these stream channels. But the equilib-
rium is changing, and as we alter our land use patterns upstream
on the watersheds, we are going to reduce the amount of water
getting into our streams, and the stream flow is going to be less and
more uniform; so we will have to look for a new equilibrium. I
can't see how we can assume that the stream flow pattern will re-
main the same when we put these upland treatments into effect.
Morris; It might be possible to establish some kind of workable
equilibrium for each of the rivers that are so investigated.
Cochran: Does siltation in water reduce its energy? Is this
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52 / PART 1 / SEDIMENT AS A WATER POLLUTANT
why, if we take silt out of the water, we have more energy to cut the
stream banks and stream bottoms?
Culbertson: You can't destroy the energy. Sediment uses some
of the energy and it reduces the turbulence that does the cutting.
The problem in erosion and deposition, as I see it, is not after it
enters the large tributary or stream. Sediment damages, as the
farmer sees it, are those that are carried on within his land and in the
immediate vicinity of the small channel. When we get to the large
streams, I personally wonder what the effect of additional erosion
control would do to the stream system.
Kirkham: In the past few years we have thought of sediment
as a pollutant because it carries nitrogen and phosphate and other
fertilizers and pesticides into the river. It is these materials that the
sanitary engineers are concerned about, because they see this tre-
mendously excessive stuff over and above that that they find from
their waste disposal plants.
Duncan: I would like to ask Dr. Shrader to comment on the
recent geological development of, particularly, northern Iowa. Ero-
sion really isn't anything new. We have had 600 or so inches de-
posited on the west side of the state fairly recently. It took quite a
little wind to deposit that from somewhere and there weren't very
many people farming then.
Shrader: I think Duncan has answered his question fairly well.
I will try to put some of this in perspective, as I see it. Yes, we've
had about 100 feet of deposition in the western part of the state, of
loess piled up there, blown out of the Missouri bottom over a period
of several thousand years, stopping a few thousand years ago. But,
to keep our perspective, I think we have to accept the fact that we
have grossly accelerated the rate of erosion here in Iowa since the
time of settlement. We are eroding our landscape in tens of years, at
a rate that would ordinarily take hundreds or even thousands of
years in certain parts of our landscape. Any way you look at it, some
of our lands are eroding at an astounding rate and the end is not
yet in sight.
Holt: I think Dr. Kirkham has a point in that people are now
associating pollution and siltation with nutrient enrichment. How-
ever, I am not convinced that we have greater nutrient enrichment
now than we had before man came here. We have more sediment
going into our streams, and this sediment is carrying nutrients.
There is no question about this. But the source of these nutrients
is an unknown.
Broiuning: Do you have some evidence to prove this?
Holt: We have some evidence that grasslands are contributing
more nitrogen and phosphorus, generally, than cultivated land, in
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CHAPTER 4 / WORKSHOP SESSION / 53
terms of solubles and nutrients in the water supply. We do have
evidence that the total amounts of nitrogen and phosphorus coming
off in the sediment are greater. We can't evaluate their availability,
but so far evidence is that they are not generally very available. The
best evidence we have is that before man came, the prairies were
supplying as many nutrients or more than are presently being sup-
plied.
Verduin: Where does the phosphorus come from for that
prairie soil?
Holt: There is an abundant supply of native phosphorus in our
soils, as Dr. Black pointed out.
Browning: We have talked about a good many problem areas;
the problems are undoubtedly different in different states. It has
been emphasized also that we have a lot more knowledge than we
are using. Little has been said about very pressing problems on
which we need more research, but we have emphasized that we do
need action.
Cochran: I have listened to a lot of experts the past few years—
Dr. Morris from the University of Iowa, for example. He didn't take
us back to before the time of civilization, but he did give us some
results of the monitoring program on various streams and major
rivers of Iowa, and he pointed out that the nitrogen content in the
water is rising each year—and rising rather rapidly—not too far
from Des Moines. Dr. Morris correlates it with the ever-increasing
use of fertilizer, and as that rate goes up, more and more nitrogen is
getting into our streams as we use more cultivation and less con-
servation.
Duncan: This was an excellent study, as I recall it; it was a
study of fertilizer applied on a grass slope. Measurement of the
runoff showed a very high concentration—in fact, a relatively high
percentage—of the nutrients that had been applied ran off. What
the study did not indicate was the probability of receiving precipita-
tion in this amount. It was a 21/4-inch rain in about an hour and a
half, but this was not reported. Certain kinds of monitoring will
produce the same data, particularly out of small streams.
Cochran: Dr. Kirkham raised an interesting question the first
day of the conference when he asked, "Why doesn't the government
just decide to allow crops to be planted on land where erosion isn't
a very serious problem and just not plant crops and not fertilize
heavily on the slopes where erosion takes place?" I thing that is a
perfectly fair question. Maybe the government should reconsider its
policy on this, if erosion and pollution are serious problems.
Browning: This gets back, I think, to your real basic question.
A lot of this would be solved if we would use the land the way it
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54 / PART 1 / SEDIMENT AS A WATER POLLUTANT
should be used. We don't really have a countrywide land use policy.
Your policy might say that any land having an excess of some pre-
determined slope isn't suitable for crops because it will wash away
and fill streams, and if you fertilize, it is going to carry fertilizer
with it and contaminate water, etc., so that land can't be used for
row crops. We are a long way from that kind of regulation, but I
think that when we realize our problems and what causes them, we
will be able to move people, and when they decide they want some-
thing done we will get action. I think we are making real progress,
but progress is slow.
Morris: Maybe it would be better if we had state legislation,
because the subdivision developers in the small watersheds of Sierra
and the hills that you have out there are another erosion problem.
Brmvning: I think the national, state, and local governments
should look at this thing and try to develop procedures that would
be as practical as possible.
Kerr: I don't think any one of us wants the federal govern-
ment to dictate land use policy. But the thing that the United States
does have and can use is an incentive based on the power of the
purse. The United States could use pollution as an incentive to
assist in the control of siltation, because the whole idea of pollution
control is very, very popular nationwide at this time. It seems that
this is a very opportune time to get some of these things under a
legislative umbrella.
McGill: We take the position that we own the land; we hold
title to it and we do about what we want to with it. I think, how-
ever, that if I am doing something that affects my neighbors, maybe
it is logical that I have some compulsion about the way I use the
resource.
There has been a bill in the State Senate the past two sessions
that I have been interested in. It would require anyone who shares
in cost-sharing benefits under conservation practices to file an appli-
cation for a farm plan at the local SCS office. Farm plans have been
very beneficial and farmers have followed them voluntarily, in most
instances.
Jones: The man from Nevada mentioned that we should have
state legislation for land use plans. I don't know about other states,
but the basic law establishing Soil Conservation Districts in Illinois
says that Soil and Water Conservation Districts shall establish land
use plans. Perhaps the emphasis from the urban population will
put some pressure on these districts to move in this direction.
Culbertson: Last October a national meeting of county officials
was held in Washington on the subject of sediment control. County
officials were urged to go back and try to set up these types of con-
trols within their counties. The counties in the Washington area
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CHAPTER 4 / WORKSHOP SESSION / 55
have actually had laws passed that require a builder who tears up
the land to erect a building (anything with a specified number of
square feet or acres) to install sediment control measures to insure
that the sediment that comes from that freshly dug ground would not
go onto someone else's property. This system appears to be working
very well. The state highway departments are entering into this in
new construction. One or two counties started this and it moved from
county to county.
Herpich: Was the real emphasis for this sociological, esthetic,
or economic in nature?
Culbertson: I think it must be a combination of all factors.
Economically, it is all tied together; it's like water and sediment—
you can't separate them.
Duncan: A year ago last spring, quite a bit of dust blew around
Iowa and in Illinois and Minnesota. We have increased our soy-
bean acreage from about 2Vo million acres to about 5i/> million the
past 4 or 5 years and it will probably go up another million. Land
following soybeans is easy to work on, but we need to find out why
land following soybeans tends to blow so much. This is an easy
place to start. I don't know why we don't work on some of the easy
problems instead of trying to work on the difficult research.
Browning: I am surprised that no one has talked about tillage,
though some folks have been working on it. It relates partly to
what Duncan said, because if you leave that soybean straw on the
surface, it doesn't blow a heck of a lot; but we have to rake it in the
fall or plow it under. Some work shows that you can raise almost
as many beans on land that you disk or minimum till as when you
plow. I would like for someone to respond to what Duncan has
said.
Duncan: Iowa has an absolute economic advantage producing
soybeans in the western part of the state. Farmers are finding
this out; and as a result soybeans are moving in on this deeper soil.
Hclt: Ten years ago when I first went to western Minnesota to
visit with the farmers out there, they mentioned two big problems.
One was that they were going out of growing soybeans because it
leaves the land too loose and it is too difficult to control weeds. The
other problem was controlling erosion on complex slopes. We have
been working on tillage practices as an approach to this. Generally
speaking, some form of multitillage is effective on these complex
slopes, where other practices are not. Back to soybeans—I suspect
that there may be something in the microorganisms that loosens this
soil. We have been checking roots lately, and when a soybean plant
matures and the leaves drop off, the root system is completely gone—
so I suspect there is some tie-in between the microorganisms which
exist under a soybean crop and this looseness and tendency to blow.
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56 / PART 1 / SEDIMENT AS A WATER POLLUTANT
Browning: I figured this out 27 years ago and wrote a paper
about it. In the first place, soybeans have roots that grow a lot in
about 6 weeks; they use a lot of water and then dry out, and the
wetting and drying and freezing and thawing have a granulating
effect. The second answer is: they have a lot of nodules in the roots,
and that is quite a stimulant for microbiological activity—it is about
40 times as active in this area. We carried on studies with corn and
soybeans under identical conditions; if we left that residue on, it was
loose and there was little runoff or erosion from the soybeans.
Amemiya: We can, through tillage, affect the infiltration of
rainwater into the soil, and in so doing, cut down the runoff and
soil loss problems. Some of the work of my colleague Bill Molden-
hauer indicates that corn following soybeans erodes much more than
corn following corn.
Moldenhauer: We had about 40% more water erosion from corn
following soybeans than we did from corn following corn. We
haven't measured wind erosion.
Jores: I think one of our primary needs in research right now
is good economics of soil conservation. In Illinois we haven't had a
good study since 1954.
McGill: Is it a reasonable assumption that the younger farmers
are more susceptible to these conservation practices and new ideas
and will voluntarily be more concerned with soil? Or will they look
at the almighty dollar and go at it like our grandfathers did and
plow the hills straight up and down, etc.?
Jones: I think they are more computer based and look at the
net return. And I think they are even less prone than were their
fathers or their grandfathers to use the moral side as impetus for
soil conservation.
Holt: There was a study in recent months in Illinois by Swan-
son (Journal of Soils) on the economics of conservation work. Swan-
son said that it doesn't pay, even up to 50 years' projection.
Amemiya: I think this study was based on strip-cropping, crop
rotation, and contouring. It didn't include some of the major slope
modification practices that we talked about.
Verduin: We're getting hung up again as to whether or not it
pays. We should pay a man for terracing if we are convinced that
that's what should be done to hold that soil over the next 10 genera-
tions.
Lafien: There is a lot of competition for the tax dollar, and it is
going to have to be spread around a lot. Where is the money to
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CHAPTER 4 / WORKSHOP SESSION / 57
come from? It is going to cost 800 million dollars or more to terrace
Iowa.
Verduin: That is the biggest problem, and I don't know whether
any research has been done on it. How can we get the thing going
to do the things that almost anyone will admit need to be done?
Wiersma: It's a matter of priorities again, is it not? I think
that if people who are going to pay for this are informed of the prob-
lem in the right manner, we will get the priority and I think we've
got to talk in terms of "we" rather than "they."
Browning: How do you establish priorities on things? In our
process, we get people agitated and then we get things done. So I
think it behooves people in these areas to dig out the facts and present
as well as they can alternative solutions and what they're going to
cost with and without our program. Then the people can and will
decide. I think we are going to be forced to do more of this, and the
better job we do of identifying the priorities and showing how the
benefits will accrue against the cost, the better our chance will be of
sharing in the short dollars that are available.
Wiersma: How did they get the money to put this man on the
moon? They didn't do that on economics, did they? Haven't we a
lot more concrete evidence in agriculture than they have?
Browning: Agriculture has far more specific things to show and
put values on than practically any other area—and we have prob-
ably done less of it than anyone. We must do this.
Herpich: Our Congress has already established some priorities.
They said "pollution."
Browning: We must begin to establish some of these guidelines.
We'll have some evidence but we won't have nearly enough. But
we'd better get ourselves in that position or we won't get the support
needed to do the job that's in the best interest of the public.
Kerr: Right now, our gimmick is pollution. We're in a better
position than we have ever been, if we can just proceed correctly.
Morris: Why not use air pollution also to get at the urban pop-
ulation, increasing the number of people who might be interested
in pollution. If we enlist the urban development as well as the
rural development, we might be able to make the package better than
we could with the single increment, pollution.
Broivning: This is the key to obtaining support in these areas.
Looking at legislation history, money comes in fairly large chunks—
usually a good many years after somebody has been talking about it.
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58 / PART 1 / SEDIMENT AS A WATER POLLUTANT
You have to have a genuine problem that the public will recognize.
The Congress will find the money, priority wise. If we've done our
jobs right, we'll get the kind of support we need.
Kirkham: One of these days, the American public will get so
sick of that war in Vietnam that it will be stopped. Then there
should be some extra money, and it's up to us to be ready for it.
Gattis: For many years we've known what slopes should be to
control erosion under given cropping systems. Maybe we should
work toward putting the slope on ground that will conserve the soil
and keep it in place. This is being done in some areas at a cost per
acre that is less than the cost of terracing the land. Your steep land
here would cost more, but slope alterations would be something of
a more permanent nature.
Evans: Sediment is a pollutant if man thinks it is. It is a re-
source out of place. Sediment can be useful, and it can be harmful.
Economics is at the core of this. We must find economical means of
recovering our sediment and utilizing it. We need to take an en-
vironmental approach to pollution. We must enlist the help of
ecologists. This area has been neglected. We need to develop some
type of land use plan that involves not only agriculture but also the
urban areas, and it's got to take in transportation, manufacturing,
agriculture—the whole business. We must think in terms of the
future and try, as educators and scientists, to get as many people
as possible thinking in this direction and trying to promote legisla-
tion.
Amemiya: Sediments are a problem, whether they're pollutants
or not. They are pollutants, not only because of their physical sig-
nificance but because of their chemical significance. Sediment costs
taxpayers money in maintaining irrigation ditches, canals and estu-
aries, ponds, lakes, and reservoirs. I think that proper land use,
especially on the upland areas, will go a long way toward minimizing
the sediment that enters our streams.
Pine: If sediment interferes with another beneficial use of
water, it is a pollutant. When sediment gets into lakes, reservoirs,
and other areas, it is a pollutant.
Culbertson: Many of you realize there is a problem, but we need
figures to work with. The only way to get them is to collect water
and sediment data and evaluate the problem. The Geological Survey
is one federal agency that will put up half of the money and cooper-
ate with any state agency or city, on a fifty-fifty basis, to make these
investigations. So I would suggest that if you want definite values
to attack a problem, propose this to my organization and we can
make these evaluations.
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CHAPTER 4 / WORKSHOP SESSION / 59
Verduin: If a river flowing into a lake contains so much silt
that it reduces the light penetration to a point where 1% of surface
light doesn't reach the middle of the water, then silt is a real pollut-
ant.
Manges: I think that within 5 years, society is going to tell us
sediment is a pollutant and we will be forced to do something about
it. We must be prepared to suggest a program.
Browning: Thank you very much for your participation here
this evening. This is the end of the session.
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PART TWO-
PLANT NUTRIENTS AS WATER POLLUTANTS
-------
CHAPTER FIVE.
SIGNIFICANCE OF PHOSPHORUS
WATER SUPPLIES
JACOB VERDUIN
T,
HE pollution of surface waters by domestic sewage and by
industrial waste has long been recognized as a serious evil in our
society. Unfortunately, action to ameliorate these long-recognized
sources of water deterioration has lagged far behind the recognition
of the problem. But only in recent years has a more subtle problem
come to light. It is the problem of superabundant plant nutrients
in our surface waters. These are invisible; they do not show up in
the classic BOD test used by sewage treatment plant operators to
measure the efficiency of their treatment process. And the presence
of these nutrients is usually recognized only after we see the nui-
sance levels of aquatic plant growth which they support (Sawyer,
1947; Verduin, 1964, 1967, 1968, 1969).
At first glance one would consider the addition of plant nutrients
to rivers and lakes as beneficial. This is especially true when the
low level of plant nutrients in natural waters is considered. For
example, forest streams and lakes which receive no urban or agri-
cultural runoff have phosphorus concentrations of less than 7 Mg/liter
(parts per billion) and the waters of our great Lake Superior are
mostly still in such condition. Nitrogen also is scarce in such natural
waters, and one would imagine that a bit of enrichment would be
appreciated.
However, to appreciate the damage done by even relatively
small quantities of fertilizer we must examine the modus -Vivendi of
the aquatic community. It has evolved, of course, under the low
level of nutrients described above. It consists of three major com-
ponents: (1) the microscopic autotrophic plants in the water, (2) the
heterotrophic organisms in the water, and (3) the organisms that
live on the bottom. These form a delicately balanced web of life
which can survive only so long as the delicate balance is preserved.
There are of course many complex interactions in this community,
but as an example let us consider the problem of oxygen supply.
Oxygen has a low solubility in water (about 8 mg/liter at summer
JACOB VERDUIN is Professor. Department of Botany, Southern Illinois
University.
63
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64 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
temperatures), and it must be transported to the bottom by vertical
mixing in the water column. If we add fertilizer to the lake, its
plant population will increase, and the quantity of organic matter
settling on the bottom will increase proportionately. As it decays
there, it consumes oxygen, but we have not increased the vertical
mixing rate, consequently the bottom organisms will be subjected
to lower oxygen than ever before in their history—with catastrophic
consequences. Such a sequence of events has been documented in
Lake Erie. Dr. N. Wilson Britt (1955) has described the catastrophic
extermination of the mayfly (Hexagenia) population in western Lake
Erie in 1953. This population was never reestablished, but a popula-
tion of bloodworm larvae (Chironomus), more tolerant of low oxygen,
has displaced it. Several other changes have been documented in
Lake Erie. Large numbers of dead clams have risen to the surface
during calm weather (the periods of lowest mixing rates) and the
dominant fish species has changed from walleye (Stizostedion) to
yellow perch (Perca). There is little doubt that all these changes are
attributable primarily to enhanced supplies of plant nutrients.
To focus more specifically on the levels of plant nutrients,
examine Table 5.1. It shows what to an agriculturist must seem
to be fantastically low levels of plant nutrients. Hydroponic solu-
tions, for example, are made up in mg/liter instead of the Mg/liter
used in Table 5.1. But once the shock of this feature has been over-
come, there are two highly significant features to notice: (1) While
nitrogen supplies increased by about 30% during the 20-odd years
covered by the table, phosphorous supplies increased by 480%, and
in doing so (2) the N/P ratio changed from a value of 35 to 9.2.
Even an elementary plant physiologist. will recognize that a N/P
ratio of 35 represents a medium in which phosphorus is severely
limiting, but a ratio of 9 is a well-balanced medium because the
ratio of N/P in protoplasm is about 8. Consequently the 20-year
period covered in Table 5.1 was one of greatly increased plant growth
in Lake Erie as a response to nutrient enrichment, with phosphorus
enrichment playing a spectacular role.
PRESENT LEVELS OF PHOSPHORUS IN OUR SURFACE WATERS
To appreciate the extent of the plant nutrient problem in our
surface waters an examination of the present phosphorus levels is
most revealing. Figure 5.1 presents such information for the years
1965-66. The data were provided by the Federal Water Pollution
Control Administration. Each figure on the map is the average of 2
or more stations in the vicinity of the number, with the exception
of the Sioux Falls, South Dakota, station (1,618 Mg/liter) which is in
a class by itself! The data represent samples drawn primarily from
drinkine water intakes. But it is well known that for many cities
the drinking water intake draws samples of the diluted sewage efflu-
ent from the city upstream. So it would not be unrealistic to regard
these numbers as representative of the diluted sewage effluents of
our cities, plus the contributions from agricultural drainage.
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CHAPTER 5 / PHOSPHORUS IN WATER / 65
TABLE 5.1. Comparison of nitrogen and phosphorus data in western Lake
Erie for 1942 with data for 1965-66.
Year
1942*
1965-66f
Available Nitrogen
NH,-N plus NO,-N
(ng/ liter)
261
330
Soluble
Phosphorus
(ng/ liter)
7.5
36.0
N/P Ratio
35.0
9.2
Average of 28 samples, April through December. Data of Chandler and
Weeks (1945).
f Average of 20 samples, June, July, August 1965, and March, April, May
1966. Data of J. Kishler (private communication). Samples analyzed by
the Great Lakes 111. River Basin Project Lab., Chicago.
The degree of enrichment that our waters have experienced can
be appreciated when we compare the phosphorus levels in Figure
5.1 with those observable even today in streams of forested areas.
Sylvester (1961, as reported by Mackenthun, 1965) reported soluble
phosphorus levels of 7 jug/liter for such streams. It seems likely that
our prairie streams had similar plant nutrient levels before the
prairies were converted to farmland. Therefore the aquatic communi-
ties that originally occupied our lakes and streams were adapted to
such low nutrient levels. The data in Figure 5.1 reveal that such low
nutrient levels are found today only in the open areas of the Great
Lakes. All of the major streams of the United States exhibit phos-
phorus levels five to thirty times higher than this "natural" plant
nutrient level.
OPEN AREAS OF L SUPERIOR,--
& HURON , '
100
*SIOUX FALLS \
SOUTH DAKOTA
FIG. 5.1. Total phosphorus concentrations (ortho-, meta-, and or-
ganic) in water supplies of the United States. Data provided by
FWPCA, 1965-66, averages of 18 months' collections.
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66 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
TABLE 5.2. Correlation between metabolism of Cladophora communities
and phosphorus concentrations in Lake Erie.
„, , Cladophora Community
Phosphorus
Location Concentration Photosynthesis Respiration
(^g/liter) (Mm CO2 absorbed (um CO, evolved
/9/hr) /g/hr)
Western
Lake Erie
Eastern
Lake Erie
35
10*
142
39f
12
6f
* Average of 21 samples. Unpublished data of B. A. Thumm, E. E. Klum,
and D. Lentz, Dept. of Chemistry, SUNY College at Fredonia.
t Unpublished data, K. G. Wood, Dept. of Biology, SUNY College at Fre-
donia.
The influence of such enrichment was recognized many years
ago. More than 20 years ago a study of lake fertilization by tributary
streams (Sawyer, 1947) revealed that nuisance blooms of algae arose
when phosphorus concentrations exceeded 20 Atg/liter. More re-
cently the nuisance level of filamentous algal growth (Cladophora
glomerata) in the littoral zones of the lower Great Lakes has occa-
sioned some investigation. Table 5.2 presents data (Verduin, 1968)
showing a correlation between the phosphorus supply and the meta-
bolic rate of the Cladophora community in Lake Erie. The western
Lake Erie community, which is bathed in water having about 35 Mg
of phosphorus per liter, exhibits a photosynthetic rate about 3.7
times that of the eastern Lake Erie community (Dunkirk, New York),
which is bathed in waters having about 10 Mg of phosphorus per liter.
The respiration rate of the western Lake Erie Cladophora community
is also distinctly higher than that of the eastern Lake Erie com-
munity. These data suggest that the metabolism of the Cladophora
community increases almost in linear proportion to increases in
phosphorus supplies, within the range of values presently encoun-
tered in the Great Lakes.
The influence of enhanced plant nutrient levels is widespread
today. They are responsible for foul tastes and odors in our drink-
ing water, clogging of water intake filters, and windrows of decaying
algae on our beaches. They also result in oxygen depletion in deeper
parts of our lakes, with catastrophic destruction of fish and of
bottom-dwelling organisms, and they support the weed-choked con-
dition of shallow areas. It is significant that the 1966 annual report
of the Division of Health and Safety of the Tennessee Valley Author-
ity devotes three pages to the problem of counteracting nuisance
growths of aquatic plants in the large TVA reservoirs. The following
quotation from that report is pertinent: "In Cherokee Reservoir, in
June, the last of three surveys showed oxygen nearly depleted below
the thermocline. Analysis of survey results over the past few years
revealed earlier oxygen depletion each ensuing year. The Holston
River below Kingsport was found to be highly eutrophic . . . sup-
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CHAPTER 5 / PHOSPHORUS IN WATER / 67
porting dense masses of aquatic weeds." The report postulates that
organic contributions by the aquatic weeds may have influenced the
oxygen depletion in the hypolimnion. No monitoring of phytoplank-
ton crops in the epilimnion is mentioned. It seems likely that en-
richment of the Holston River, which flows into Cherokee Reservoir,
has supported greater phytoplankton growth there, with a resultant
increase in the organic load settling into the hypolimnion. The TVA
report describes countermeasures taken to reduce nuisance growths
of aquatic plants. These include scouting of dense plant concentra-
tions by aerial surveillance, and the helicopterized application of
2, 4-D pellets. Thus we counteract the pollution due to plant nu-
trients by adding another chemical pollutant, a plant toxin!
THE RELATIVE CONTRIBUTIONS OF URBAN SEWAGE,
PHOSPHATE DETERGENTS, AND AGRICULTURAL DRAINAGE
TO THE PHOSPHORUS LEVELS IN SURFACE WATERS
Up to this point we have been concerned primarily with estab-
lishing the significance of plant nutrients as water pollutants, and
with an inspection of the level of a key plant nutrient, namely
phosphorus. Because this symposium is concerned about the role of
agriculture in clean water, we can best advance that concern by
trying to evaluate agriculture's contribution to the phosphorus levels
now prevailing in our surface waters. Such evaluation can be made
by examining the concentrations in streams whose watershed rep-
resents agricultural land and does not include urban runoff. Table
5.3 presents data of this kind compiled from several sources. These
TABLE 5.3. Soluble phosphorus concentrations reported for waters from
agricultural watersheds.
Author Watershed Phosphorus
(/jig/liter)
Engelbrecht and Kaskaskia River
Morgan, 1960* (111-) 60
Sawyer, 1947* Watershed, farmlands
agricultural drainage
around Lake Mendota 48
Putnam and Olson, St. Louis and Black
1960* rivers, tributaries
of western Lake Superior 40
Harlow, 1966t Raisin River
(Mich.) 60
Owen, 1965f Ontario agricultural
watershed 33
Hardy, 1966t Big Muddy
(111.) river system,
upstream portions 110
Average 58
* As reported by Mackenthun (1965).
t Private communication, plus papers presented at the 9th Conf. on Great
Lakes Res., Chicago, 1966.
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68 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
TABLE 5.4. Comparison of upstream station phosphorus values (assumed to
represent agricultural runoff and drainage) with values at the
mouth of the Big Muddy River (representing the combined con-
tribution from agricultural and urban effluents).
Four upstream stations, average of 4 samples
at each station 110 /ig/liter
River mouth station, average of 4 samples 350 /ig/liter
Percentage of total attributed to agriculture 31%
Source: Private communication. Hardy supervised collection of samples.
Chemical analyses were performed by the Great Lakes 111. River Basin
Project Lab. in Chicago. Statistical analyses were made by Richard Rowe
of the Southern 111. Univ. School of Technology.
data show that runoff from rural watersheds represents a significant
fraction of the phosphorus appearing in our surface waters. The
data in Table 5.3 represent rural watersheds from the upper Missis-
sippi and Great Lakes region, the same region for which phosphorus
levels of 175 Mg/liter are shown in Figure 5.1. The average value of
58 /ug/Hter in Table 5.3 suggests that approximately one-third of the
phosphorus contribution may come from agricultural watersheds.
Some data collected by George Hardy, a sanitary engineer with the
Illinois Department of Health during the summer of 1966, permit
a similar evaluation for a single river system, the Big Muddy in
southern Illinois. Table 5.4 presents these data. This analysis also
indicates that about one-third of the phosphorus concentration found
at the mouth of the Big Muddy may be attributed to agricultural
sources. Upon consulting with fertilizer dealers in the Big Muddy
watershed, it was learned that farmers apply fertilizers in such
quantity that the PO4 added amounts to about 100 Ib/acre. If 1% of
this addition is dissolved in the annual runoff and drainage it would
create a phosphorus concentration of about 50 Mg/liter, which is
similar to the average value in Table 5.3. Obviously the farmer is
not going to be impressed by the fact that 1% of his phosphate ap-
plication is lost in runoff and drainage; neither do any practical
measures for reducing this contribution come to mind.
A somewhat encouraging aspect of the above analysis, at least
for the agriculturist, is that agriculture appears to be responsible
for less than half of the phosphorus supplies in our waters. The
supply from urban sources seems to represent the major fraction.
In urban sewage effluents, detergents seem to contribute about three
times more phosphate than is contributed by the organic matter in
sewage, according to Engelbrecht and Morgan (Mackenthun, 1965).
Consequently, detergents would appear to be the most significant
single source of phosphates enriching our waters today. Unfor-
tunately their use is still increasing. I am told that some weed and
orchard sprays contain these detergents to prevent clogging of spray
nozzles. And our northern cities are now adding these detergents
to salt applications on icy streets. The detergents presumably act
as rust inhibitors.
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CHAPTER 5 / PHOSPHORUS IN WATER / 69
THE SIGNIFICANCE OF PRESENT PRACTICES
OF ANIMAL MANURE DISPOSAL
There is a fairly recent development in agricultural practice that
is most distressing. For hundreds of years the successful farmer has
been spreading animal manures and decayed vegetable composts on
his land. But in recent years feedlot operators have been installing
lagoons to decompose the animal manures. These ancient, tried and
true soil improvers are now being digested in lagoons, and the plant
nutrients that remain in solution after the digestion is completed are
discharged to our surface waters in the lagoon overflow! Prepare
yourselves for a dogmatic statement: Manure belongs on the land.
To be sure, the agricultural economist may be able to demonstrate
that it is cheaper to buy chemical fertilizers than to spread manure.
But it certainly cannot be a great deal cheaper, and if our Agricul-
tural Stabilization Service can pay the farmers for not raising feed
grains or cotton, then it should certainly consider paying the feedlot
operator for not lagooning animal manure, because manure belongs
on the land. Manure contains many trace elements, vitamins, soil
conditioners, etc., which chemical fertilizers do not provide, and
organic manures represent the only economically feasible source of
CO., fertilization. With our modern crop densities the COo content of
air among the leaves drops spectacularly, especially in quiet weather
(Verduin and Loomis, 1944). A healthy layer of decaying organic
matter will serve to augment the atmospheric CO2 supply significant-
ly. The method we use in solving a problem is profoundly influenced
by the initial conception of the problem. If we regard a concentration
of animal manure as a disposal problem, we are likely to adopt the
least expensive means of disposal available, and the lagoon may well
fit the bill. But if we regard a concentration of animal manure as a
valuable source of fertilizer and soil conditioner, the problem is one
of transportation and application—it is not a disposal problem at all,
and a lagoon will never be considered a solution to the problem.
METHODS OF ALLEVIATING THE PROBLEM
OF WATER POLLUTION BY PLANT NUTRIENTS
Phosphorus is a key element in the problem of pollution by plant
nutrients because it is present in such low concentrations in natural
waters and because it has undergone much more spectacular in-
creases than any other plant nutrient. The agricultural practices
which would tend to reduce the agricultural phosphorus contribu-
tion are simply sound soil conservation practices: (1) methods of
cultivation which minimize runoff, (2) insuring intimate mixture of
fertilizer with soil, (3) improving soil texture by addition of animal
manures and ploughing in legume stands, and (4) particularly,
abandoning the practice of lagooning animal manures. But the fact
that the major phosphorus contributions come from nonagricultural
-------
70 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
sources shifts the burden of problem solution elsewhere. However,
the solution is of interest to the agriculturist as well as to any other
citizen, and more so because agriculture can make distinct contribu-
tions to the solution of this problem.
The contribution of agriculture to the solution of the problem
has two facets: (1) The same condemnation made above of the de-
composition of animal manures in a lagoon applies to the decomposi-
tion of organic matter in urban sewage treatment plants. This or-
ganic matter, considerably enhanced today by the use of garbage
disposal units in our kitchens, is as good for the land as animal
manure, and it should be so utilized. Again, if we stop thinking of
the problem as a waste disposal problem and look at it as a problem
in processing, transporting, and applying a valuable soil conditioner,
our attack on it will be drastically altered. Because the organic
matter includes human excrement we have a pasteurization
problem, but the fact that the organic matter is suspended in water
introduces a drying problem. If the drying is done at sufficiently
high temperature, pasteurization will be automatic. Moreover, we
may well be able to utilize the "waste" heat from thermal electric
power plants—heat which is now being widely decried as thermal
pollution! Once the organic matter is pasteurized and dried we
should call in the chemical fertilizer industry to add as much of
their product as is needed to provide a maximally advantageous fer-
tilizer. Then we should pelletize this product so the farmer can dis-
pense it from attachments on his plough, disc, drill, and planter,
thus avoiding extra trips over the landscape.
(2) Even after all settleable solids are removed from the sew-
age, a high level of dissolved organic matter and plant nutrients,
especially detergent phosphorus, will remain in the urban effluents.
The most promising method of treating such effluents is again an
agriculture-related treatment. It is the "living filter" described by
Kardos in the AAAS symposium on Agriculture and the Quality of
our Environment (Kardos, 1967). If such sewage effluents are
allowed to percolate through the root zone of crop plants or trees,
the dissolved materials are removed effectively and diverted to pro-
mote valuable plant growth. The water emerging from tiles beneath
these root zones can be released to our surface waters without fear of
serious pollution.
It is obvious that agriculture has a primary role to play in the
solution of the pollution problem. Where it is contributing plant
nutrients directly, it should attempt to minimize such contributions,
but wherever plant nutrients are entering our surface waters from
nonagricultural sources, we should recognize the agricultural poten-
tial of such plant nutrient sources and attack the problem of restor-
ing them to the land. In the problem of removing concentrated nu-
trients from water, agricultural technology can make a major con-
tribution in the application of the living root zone filter to the process
of plant nutrient removal.
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CHAPTER 5 / PHOSPHORUS IN WATER / 71
REFERENCES
Britt, N. W. 1955. Stratification in western Lake Erie in summer
1953: effects on the Hexagenia (Ephemeroptera) population.
Ecology 36:239-44.
Chandler, D. C., and Weeks, O. B. 1945. Limnological studies of
western Lake Erie. V. Relation of limnological and meteorolog-
ical conditions to the production of phytoplankton in 1942.
Ecol. Monographs 15:435-56.
Engelbrecht, R. S., and Morgan, J. J. 1959. Studies on the occur-
rence and degradation of condensed phosphate in surface
waters. Sewage Ind. Wastes 31:458-78.
Kardos, Louis T. 1967. Waste water renovation by the land—a liv-
ing filter. In Agriculture and the quality of our environment, ed.
Nyle C. Brady, pp. 241-50. Norwood, Mass.: Plimpton Press.
Mackenthun, K. M. 1965. Nitrogen and phosphorus in water. U.S.
Health, Education and Welfare Publ.
Sawyer, C. N. 1947. Fertilization of lakes by agricultural drainage.
/. New Engl. Water Works Assoc. 61:109-27.
Tennessee Valley Authority. 1966. Annual report of Division of
Health and Safety.
Verduin, J. 1964. Changes in western Lake Erie during the period
1948-1962. Verhandl. Intern. Ver. Limnol. 15:639-44.
. 1967. Eutrophication and agriculture in the United States.
In Agriculture and the quality of our environment, ed. Nyle C.
Brady, pp. 163-72. Norwood, Mass.: Plimpton Press.
. 1968. Reservoir management problems created by increased
phosphorus levels of surface waters. Am. Fish. Soc. Symp.,
pp. 200-206. Athens: Ga.: Univ. of Georgia Press.
1969. Man's influence on Lake Erie. Ohio J. Sci. 69:65-70.
Verduin, J., and Loomis, W. E. 1944. Absorption of carbon dioxide
by maize. Plant Physiol. 19:278-93.
-------
CHAPTER
BEHAVIOR OF SOIL AND
FERTILIZER PHOSPHORUS IN
RELATION TO WATER POLLUTION
C. A. BLACK
T,
HE principal objective of this chapter is to present an account
of selected aspects of the behavior of soil and fertilizer phosphorus as
a basis for understanding how phosphorus from these sources may
contribute to the phosphorus content of waters in the soil and leaving
the soil. An attempt is made to place these matters in perspective
in the broad picture without undue encroachment on the aspects of
the subject covered by other contributors to the symposium.
Although the basis for the subjects discussed is mostly chemical,
an exhaustive review of current knowledge of the chemistry of phos-
phorus in soils and fertilizers will not be attempted because such a
review would lose sight of the objective. Chemically oriented reviews
have been published by Dean (1949), Wild (1950), Hemwall (1957),
Larsen (1967), Mattingly and Talibudeen (1967), and Huffman
(1968). Taylor (1967) published a review on phosphorus and water
pollution with emphasis similar to that in this chapter.
PHOSPHORUS CYCLE IN SOIL
Vertical cycle
Plant roots continually absorb small amounts of phosphorus
from soil, generally less than 15 kg per hectare annually. The major
portion of the phosphorus is transported to the above-ground organs.
The phosphorus not contained in harvested parts is returned to the
surface of the soil in the plant residues.
The phosphorus added to soil in plant residues is constrained
against downward movement by a mechanical sieving action of the
soil, which is effective on the solid residues, and by a chemical siev-
C. A. BLACK is Professor, Department of Agronomy, Iowa State
University.
Journal Paper No. J-6373 of the Iowa Agriculture and Home Eco-
nomics Experiment Station, Ames. Project No. 1183.
72
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CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 73
ing action, which is effective on the phosphorus that has been re-
leased from the residues to the water in the soil. The existence of a
chemical sieving action is suggested by data by Ponomareva et al.
(1968) showing that the concentrations of phosphorus in micrograms
per rnilliliter in drainage water from successively deeper layers in a
soil from the USSR were 0.005, 0.001, 0, 0, and 0. Similarly, Barber
et al. (1962) measured an average concentration of 0.18 Mg of inor-
ganic phosphorus as orthophosphate per milliliter of the saturation
extract of the 0- to 15-cm layer of soils of midwestern United States
and 0.08 p.g per ml of the saturation extract of the 46- to 61-cm layer
of the same soils.
The combination of upward transport of phosphorus in the soil
profile by plants and the retention of phosphorus by the soil against
downward transport by water may significantly alter the vertical
distribution of phosphorus in the soil. In soils that have been sub-
jected to moderate weathering and leaching, a minimum in the con-
centration of total phosphorus in the soil may be found a small dis-
tance below the surface (Fig. 6.1).
20
40
£
u
80
100
120
Dilute- |
acid- 11
soluble I x
inorganic £ |
0
0.02
0.04
0.06
0.08
Phosphorus content of soil,%
FIG. 6.1. Vertical distribution of phosphorus in a soil developed on
loess under grass vegetation in Iowa. (Pearson and Simonson, 1939;
Pearson et al., 1940. Reproduced by permission of John Wiley & Sons,
Inc., New York.)
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74 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Chemical cycle
The phosphorus plants absorb from soil is presumably inorganic
orthophosphate. In plants, perhaps half of the phosphorus occurs
as inorganic orthophosphate and almost all the remainder as various
organic forms. Plant residues therefore return to the soil some in-
organic phosphorus and some organic phosphorus.
Inorganic phosphorus, present in relatively high concentration
in the plant sap, diffuses readily from the dead plant material into
the soil. In the soil it reacts with the soil minerals, and the concen-
tration in solution is much reduced, as may be inferred from the ex-
periment by Ponomareva et al. (1968) discussed previously.
A small proportion of the organic phosphorus probably diffuses
out of the plant residues into the soil, but most of it is not readily
soluble in water and presumably must be acted upon by microor-
ganisms before it is released. Despite rapid decomposition in the
first few months, however, complete disappearance of added organic
matter requires a long time. A consequence is that during soil de-
velopment organic phosphorus is produced at the expense of inor-
ganic phosphorus. The accumulation of organic phosphorus parallels
the accumulation of organic carbon, nitrogen, and sulfur (Jackman,
1964), and the content of organic phosphorus is usually greatest at
the surface and decreases with depth, as is true also of other organic
constituents (Pearson and Simonson, 1939). Figure 6.1 shows the
vertical distribution of organic phosphorus in one soil profile. In
time, presumably, a steady state is reached in which organic phos-
phorus changes to the inorganic form as rapidly as it is produced.
When soils are cultivated, the previously existing balance be-
tween formation and decomposition of organic phosphorus is upset.
Generally the content of organic phosphorus decreases (Haas et al.,
1961; Cunningham, 1963).
One other aspect of the chemical cycle worthy of particular men-
tion is that inorganic orthophosphate ions in the soil solution ex-
change continuously with inorganic orthophosphate ions held by the
soil solids (but not with organic orthophosphate). The classic paper
on this subject was published by McAuIiffe et al. (1948). In each soil,
some of the solid-phase phosphorus exchanges readily with added
radioactive phosphorus, some exchanges more slowly, and usually
most exchanges extremely slowly, if at all. Phosphorus is supplied
to the solution from the readily exchanging fraction in response to
removal of phosphorus from the solution and is transferred from
the solution to the readily exchanging fraction in response to
addition of phosphorus to the solution from external sources. The
readily exchangeable fraction, in turn, gains phosphorus from other
sources in the soil when its level is decreased, and it loses phos-
phorus to other forms when its level is increased by phosphorus addi-
tions. Larsen (1967) gave an exceptionally clear picture of these
transformations.
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CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 75
GEOLOGIC PHOSPHORUS CYCLE
Soil contributes to the geologic phosphorus cycle by supplying
phosphorus in solution to ground-water and surface water and by
supplying phosphorus in suspended solids to surface water and air.
Emphasis here will be on the parts involving water.
Loss of phosphorus from soil by drainage into the groundwater
is a normal part of the geologic phosphorus cycle. Indirect evidence
of various kinds (Clarke, 1924; Weir, 1936; Wild, 1961; Ludecke,
1962) indicates that during the time required for soil to develop
from parent material, a substantial part of the original phosphorus
may have disappeared, presumably as a result of downward move-
ment of water through the soil. The annual losses are so small in re-
lation to the amount present, however, as to be undetectable by
analyses made of the soil over a span of a few years or perhaps even
a lifetime.
Loss of phosphorus due to downward movement of water
through the soil on a short-time basis is commonly determined by
analyzing the drainage water from a lysimeter, in which the depth
of soil is usually no more than a meter, or by analyzing water from
tile drains. The concentrations are usually less than 0.1 ^g of phos-
phorus per milliliter (Voelcker, 1874; Kohnke et.al., 1940; Morgan
and Jacobson, 1942; Sylvester and Seabloom, 1963). Analyses for
phosphorus are often omitted because the concentrations are so con-
sistently low.
Two difficulties in interpretation of values obtained as just
described are that (1) part of the water in tile drains has passed
through strata beneath the tiles and (2) the phosphorus filtering
process that goes on in soil proper takes place even more effectively
in unconsolidated material underlying the soil. Occurrence of a zone
of relatively high phosphorus content in the unconsolidated ma-
terial below the soil (Huddleston, 1969) is evidence that some of the
phosphorus leached from the soil is retained by the material beneath
and that the estimate of loss of phosphorus to the groundwater by
leaching may depend on the depth at which the water is collected.
Because of the effectiveness of soil and underlying material in
retaining phosphorus, the phosphorus content of groundwaters is
normally low. A value of 0.011 ^ig of phosphorus per milliliter is
obtained by averaging 63 of the 65 analyses reported by White et al.
(1963) in a survey of data. Two high values not included in the
average were 0.15 and 0.36 ng of phosphorus per milliliter. Juday
and Birge (1931) reported an average of 0.016 Mg of phosphorus per
milliliter in water from 17 wells near lakes in northeastern Wiscon-
sin (2 additional wells had phosphorus contents of 0.086 and 0.197
Mg per milliliter) and an average of 0.023 Ag of phosphorus per mil-
liliter of lake water. Groundwaters may thus be expected to be low
in phosphorus in most instances.
Surface waters present a different sort of problem because they
contain phosphorus in both dissolved and particulate form. The
solids are derived primarily from surface soils (Gottschalk, 1962),
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76 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
FIG. 6.2. Concentration of
phosphorus in solution af-
ter equilibration of soils
of France with superphos-
phate versus calculated
concentration in solution
due to phosphorus added.
Two parts of water were
equilibrated with one part
of soil. Each line repre-
sents a different soil.
(Demolon and Boischot,
1951.)
5 10
Phosphorus added per milliliter,
most of which have, in the soil solution, concentrations of phosphorus
exceeding the value of 0.015 vg per milliliter, quoted by Mackenthun
(1965) as a concentration of phosphorus sufficient to produce a sub-
sequent nuisance growth of algae in water. Data on phosphorus in
soil solutions were published by Pierre and Parker (1927) and Barber
et al. (1962). Another source of phosphorus in surface waters is dead
plant residues on the surface of the soil. These residues release
phosphorus readily, and the initial phosphorus concentrations are
much above those generally found in soil solutions.
The suspended solids impart to the stream a phosphorus-buffer-
ing quality, illustrated in principle in Figure 6.2. That is, when the
solids are initially suspended in rainwater or when the stream is later
diluted by low-phosphorus water, release of phosphorus from the
solids will make the concentration of phosphorus in the final mixture
closer to that in the original soil solution than would be predicted
from a simple dilution effect. Conversely, if a stream receives high-
phosphorus water from another source, such as sewage, the soil-
derived solids will take up phosphorus from the water and will reduce
the concentration of phosphorus in solution.
Whether the entrance of groundwater into streams increases or
decreases the concentration of phosphorus in the stream water de-
pends on the relative concentrations of phosphorus in the two. If the
stream is one that carries substantial amounts of suspended solids
from surface soils and receives sewage effluent at intervals, it seems
unlikely that entrance of the groundwater will raise the concentra-
tion of phosphorus. But, even if the groundwater originally has a
lower concentration of phosphorus than the stream water, the ground-
water may not much lower the concentration in the stream because
of the buffering effect of the solids. Groundwater enters streams
mainly through the sides and bottom of the channel, and it must pass
through the previously deposited sediments in the stream bed and
must be substantially at equilibrium with them by the time it enters
the stream proper.
Concentrations of inorganic orthophosphate in the water of
streams and lakes are extremely low by conventional standards.
Plants are extremely efficient in absorbing phosphorus, however, and
-------
CHAPTER 6 / SOU AND FERTILIZER PHOSPHORUS / 77
if other conditions are favorable, will reduce the external concen-
tration of phosphorus essentially to zero. Absorption of dissolved
phosphorus by aquatic plants starts a biological cycle in which ani-
mals feed on the plants and the residues of both decompose, with
release of inorganic orthophosphate that starts around the biological
cycle again.
This biological cycle continues after the water has reached the
oceans. But the depth and circulation of oceans introduce some
changes. Photosynthesis occurs only near the surface because of
the requirement for light. The residues of both plants and animals
sink and decompose at great depths or on the bottom, where there
is little synthesis. Consequently the inorganic phosphorus content of
surface water is low, and that of deeper water is higher. Circulation
of the oceans brings up water from the depths and renews the supply
of phosphorus for the biological cycle.
Despite the annual addition of an estimated 2 million metric
tons of dissolved phosphorus to the oceans (McKelvey et al.. 1953),
the phosphorus concentration in ocean water remains low because
of continuous loss of phosphorus from the biological cycle, the princi-
pal loss being due to formation of the mineral apatite. According to
Kazakov's theory (McKelvey et al., 1953), the cold ocean water from
great depths, which contains a relatively high concentration of carbon
dioxide and inorganic orthophosphate, becomes supersaturated with
respect to apatite as it flows upward, warms, loses carbon dioxide,
and increases in pH. Solid-phase apatite is then slowly formed.
Apatite is forming now off the coast of California under these condi-
tions, according to Dietz et al. (1942). If the apatite is formed in a
place that receives little extraneous sediment, a substantial and high-
grade bed of "phosphorite" or "phosphate rock" may be developed
over geologic time. If, later, the bed of phosphorite is uplifted and
occurs above sea level, the geologic phosphorus cycle begins again
with loss of phosphorus by leaching. Phosphorus in phosphorite
reenters the geologic cycle in another way in that beds of this sub-
stance located now on land supply almost all the phosphorus used
for fertilizers and other purposes.
REACTION OF FERTILIZER PHOSPHORUS WITH SOILS
Nature of fertilizer phosphorus
The phosphorus in phosphorite is present as orthophosphate
(PO4- - -), and it remains as orthophosphate when phosphorite is proc-
essed to form the more soluble phosphate compounds that contain
the bulk of the fertilizer phosphorus. In some modem fertilizers,
however, a part or most of the phosphorus is now appearing as con-
densed phosphates, in which two or more orthophosphate groups
are joined through an oxygen atom. The solubility of condensed
phosphates decreases with an increase in size of the molecules.
The chemistry of condensed phosphates is somewhat different
from that of orthophosphates (Huffman, 1968). For present pur-
-------
V
FIG. 6.3. Crystalline phosphates formed from the interaction of phos-
phate fertilizers with soils. A. Crystals of calcium ammonium phos-
phate [CadslHiWHPCXkHaO (dimorph B)] formed on calcium carbonate
in a calcareous soil to which dibasic ammonium phosphate was added
as fertilizer. The fertilizer was added in a thin layer and moved up-
ward into the soil. The surface of the calcium carbonate shown in the
picture was oriented perpendicular to the layer of fertilizer and paral-
lel to the direction of movement. (Bell, 1968.) B. Variation in content
of calcium ammonium phosphate [Ca(NHi)o(HPOi)2.H2O (dimorph B)]
with original pH of a soil when dibasic ammonium phosphate was al-
lowed to move upward into a column of soil from a thin layer at the
bottom. The soil is dark colored, and the intensity of the sprinkling of
white indicates the relative amount of calcium ammonium phosphate
formed. The sample in each case was taken from a 2-mm layer of soil
adjacent to the fertilizer and had been pressed into a brass ring pre-
:
-------
paratory to examination by X-ray diffraction. (Photograph courtesy of
L. C. Bell.) C. Crystals of magnesium ammonium phosphate hexahy-
drate (MgNH4PO4.6H2O) developed in a soil high in exchangeable
magnesium when monobasic ammonium phosphate moved upward into
a column of the soil from a thin layer of the salt at the bottom. Values
for cation-exchange capacity, exchangeable calcium, and exchangeable
magnesium in the soil were 54, 38, and 12 m.e. per TOO g, respectively.
(Photograph courtesy of L. C. Bell.) D. Cross section of an originally
neutral, high-calcium soil, adjacent to a granule of concentrated super-
phosphate, showing development of crystals of dibasic calcium phos-
phate dihydrate (CaHPCX.2H«O). Although the soil contains a large
amount of the newly formed crystalline phosphate, most of the crystals
are too small to be identified at this magnification. Only a few rela-
tively large crystals may be seen.
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80 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
poses, however, it is perhaps sufficient to say that (1) condensed
phosphates spontaneously decompose in soil, gradually forming
orthophosphates, and (2) in the meantime they are present in forms
that are probably no more readily lost from the soil than are ortho-
phosphates.1
Reactions at high phosphorus concentrations
The quantities of phosphate fertilizers added to soil are rarely
great enough to produce a high phosphorus concentration in the
soil solution if the fertilizer phosphorus were uniformly distributed,
but uniform distribution is never accomplished in practice. Initially
the solution is usually saturated with the fertilizer salt at the imme-
diate site of application, and the concentration of phosphorus is of
the order of 1 million times greater than the concentration of phos-
phorus in soil solutions and streams.
Soils invariably contain cations that form phosphates of low
solubility (calcium, magnesium, aluminum, and iron are of principal
importance), and such phosphates form rapidly in soil in the presence
of the high concentrations of phosphorus found near the site of the
fertilizer. Some of the phosphates are crystalline, and the crystals
may be seen under a microscope and occasionally even with the
unaided eye. Figure 6.3 shows some examples. The kinds and
amounts formed depend on the nature of the soil and fertilizer and
on other factors as well (Bell, 1968; Huffman, 1968). Formation of
these compounds greatly decreases the tendency of the phosphorus
to move in the soil water by either mass movement or diffusion.
The crystalline phosphates that form quickly in soil when sol-
uble phosphate fertilizers are added disappear with time when the
concentration of phosphorus decreases. They may simply dissolve
(Larsen et al., 1964), or they may leave a less soluble phosphate as a
residue (Bell, 1968). In either case the phosphate released does not
stay in solution but is retained in some way by the soil solids. There
is some evidence for eventual formation of crystalline phosphates of
extremely low solubility (Nagelschmidt and Nixon, 1944; Australia,
1956; Bell, 1968). On the other hand, if the phosphorus concentration
is maintained, the quickly forming phosphates may be stable indefi-
nitely. This situation will be discussed in the section on reaction
capacities.
1. Scott (1958) investigated the reaction of orthophosphate and
condensed phosphates (from calcium metaphosphate fertilizer,
vitreous calcium metaphosphate, sodium metaphosphate, and am-
monium metaphosphate) with soils and found that the soils tested
sorbed the condensed phosphate more strongly than the orthophos-
phate. Sample (1965) was quoted by Huffman (1968) as having
found that pyrophosphate was taken up by soil more rapidly than
orthophosphate but was retained less strongly. Gunary (1966) found
that most soils he tested had a higher "adsorption maximum" for
pyrophosphate than for orthophosphate. The adsorption concept is
discussed in a subsequent section.
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CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 81
Reactions at low phosphorus concentrations
Reactions at low phosphorus concentrations are important at the
perimeter of the zone of soil containing fertilizer phosphorus and also
in stream waters, where suspended and sedimented solids interact
with waters having low concentrations of phosphorus. Figure 6.2
shows that as phosphorus was added to suspensions of soil in water
the concentration of phosphorus in solution increased, slowly at first
and then more rapidly, but the concentrations of phosphorus in solu-
tion with no addition and the rates of increase with phosphorus ad-
ditions differed among soils. These observations signify that soils
react most strongly with the first increment of added phosphorus and
less strongly with succeeding increments and that the reaction has
both an intensity aspect and a quantity aspect.
The Freundlich and Langmuir equations used in colloid chem-
istry to describe adsorptions have both been used to express the reac-
tions of soil with low concentrations of inorganic orthophosphate.
Recently attention has been focused on the Langmuir equation.
Olsen and Watanabe (1957) used the equation in the form
C 1 C
— 1
x/m kb b
in which C is the equilibrium phosphorus concentration, x/m is the
quantity of phosphorus adsorbed per unit weight of soil, b is the maxi-
mum quantity of phosphorus that can be held by adsorption per unit
weight of soil, and k is a parameter related to the bonding energy of
the soil for phosphorus. If experimental data fit the equation, a plot
of C/x/m against C should yield a straight line with slope 1/b and
intercept 1/kb, from which b and k may be evaluated. The quantity
of phosphorus found in the soil by isotopic dilution of radioactive
orthophosphate was used as an estimate of the phosphorus already
present in adsorbed form.
Figure 6.4 shows Olsen and Watanabe's data for two soils. From
the equations, it may be seen that Pierre clay had a higher adsorp-
tion capacity (b = 25.9 mg P/100 g soil) than Owyhee silt loam
(b = 13.3 mg P/100 g soil) and that Pierre clay bonded phosphorus
more strongly (fe — 1.32 x 104 liters/mole) than did Owyhee silt
loam (k - 0.94 x 104 liters/mole).
The constants in the Langmuir equation provide a convenient
way to represent the phosphorus-adsorbing properties of soils in the
presence of low concentrations of phosphorus in solution and provide
reasonable bases for comparing different soils if the procedures are
standardized. Moreover, the Langmuir equation may be used to de-
scribe phosphorus release or desorption from soil as shown by Fried
and Shapiro (1956).
The experience obtained in use of the Langmuir equation with
soils suggests that it may be useful also for describing phosphorus
adsorption and release by solids suspended in streams. Nevertheless,
the results should not be taken too seriously because the equation is
empirical as applied to interaction of phosphorus with soil, and the
-------
x
Owyhee silt loam
0
FIG. 6.4. Plot of phosphorus adsorption data for two soils according to
the Langmuir equation. In each case the first five points fall close to
a straight line, indicating conformance to the equation, and the sixth
point deviates from the line. (Olsen and Watanabe, 1957.)
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CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 83
equation does not fit data from all soils (Fried and Shapiro, 1956;
Olsen and Watanabe, 1957; Thompson et al., 1960). Deviation of
the data from a linear plot at high concentrations, illustrated in Fig-
ure 6.4, is a common problem; this means that the adsorption capacity
must be calculated and not determined directly. Olsen and Watanabe
(1957) quoted other work suggesting that the deviation might be due
to formation of crystalline phosphates.
Reaction capacities
Of great importance in the behavior of phosphorus in soil in
relation to water pollution is the capacity of soil to react with phos-
phate. There is much confusion on this matter because soils are so
complex, conditions are so many, and measurement capabilities
are so limited.
For present purposes, it seems reasonable to describe, conceptu-
ally, three kinds of capacities. Each is significant under different
circumstances.
First is the capacity of the soil to react with phosphorus at low
concentrations. This is the so-called adsorption capacity discussed
in the preceding section. It is of significance in both soils and streams.
Second is the capacity of soil to react rapidly with phosphorus
added at high concentrations, as when water-soluble phosphate fer-
tilizers are added as solids. This capacity is significant in determin-
ing the capability of soil to capture fertilizer phosphorus in new solid
phosphate species and to retain the phosphorus near the site of its
introduction into the soil. This capacity could be defined operation-
ally in many different ways, yielding many different values. Under
conditions such as those of practical concern in the field, this capac-
ity or these capacities far exceed the adsorption capacity discussed
in the preceding paragraph.
Third is the ultimate capacity of soil to react with phosphorus.
The ultimate capacity is equal to the phosphorus retained by the total
amount of cations in the soil capable of forming phosphates of low
solubility. This capacity is far greater than the capacity of soil to
react rapidly with phosphorus added at high concentrations.
The ultimate capacity is evoked when soil has been in contact
with a solution of high phosphate concentration for a long time.
The original carbonate, hydrous oxide, and silicate minerals are then
decomposed, with release of soluble silica from the silicates, and the
product is a bed of phosphates.
There is no known instance in which soil has been thus altered
by addition of phosphate fertilizer, but there is no doubt of the validity
of the concept. In a classic paper, Gautier (1894) traced a layer of
clay that had entered a cave in France through a fissure in the rock
and found that the clay had been altered to an aluminum phosphate
where it had been contacted by water derived from bat guano. Many
instances are known of alteration of rocks to phosphates under the in-
fluence of leachings from guano in caves and on ocean islands.
Teall's (1898) photomicrographs of thin sections of trachyte slightly
-------
FIG. 6.5. Photomicrographs of thin sections of trachyte altered by
phosphate from overlying guano on Clipperton Atoll. A. Altered tra-
chyte, showing phenocrysts of sanidine set in a groundmass of micro-
litic feldspars and brown interstitial matter. In the central lower por-
tion of the photomicrograph is a crystal of the feldspar crowded with
brown inclusions. The phosphorus is present in the brown substance.
B. Highly altered trachyte, showing the replacement of feldspar by
phosphate with concretionary structure. The groundmass is replaced
by a similar material, but without concretionary structure. The outline
of one of the feldspar crystals is clearly seen in the lower right por-
tion of the photomicrograph, but the original substance has been re-
placed by the phosphate. (Teall, 1898.)
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CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 85
TABLE 6.1. Chemical composition of trachyte at different degrees of altera-
tion under guano on Clipperton Atoll.
Constituent
SiO,
p,O-,
Fe.O:,
CaO
K o
Na-O
Loss on ignition
Matter insoluble in HC1
Least
Altered
Sample
5^ 0
84
17.9
4.4
1.4
4.5
50
3.8
Considerably
Altered
Sample
43 7
17 0
12.3
Highly
Altered
Sample
2 8
38 5
25.9
7.4
23.0
2.2
Total 99.4 . . . 99.8
Source: Teall (1898).
altered and strongly altered by bird guano are reproduced in Figure
6.5, and his data showing the change in chemical composition of the
rock with degree of alteration are given in Table 6.1. The inverse
relationship between phosphorus content and silicon content is par-
ticularly noteworthy.
Laboratory work has verified that soils, clay, and minerals may
indeed be altered to phosphates. Gautier (1894) demonstrated the al-
teration of gelatinous alumina, clay, siderite, and chalk to phosphates.
Tamini et al. (1964) reported recent work on gibbsite and soils and
reviewed some of the previous work. Clarke (1924) reviewed early
work. Modern researchers have better tools than their predecessors
and now can determine more easily the nature of the phosphates
formed. Figure 6.6 shows, for example, a cross section of a crystal
of calcite, the surface of which had been altered by a sodium phos-
phate solution to a calcium phosphate identified by X-ray diffraction
as apatite.
The second and third kinds of capacities are usually great
enough to enable soil to retain a tremendous amount of phosphorus
near the site of application of soluble phosphate fertilizer. At the
same time, the combined effect of all three kinds of capacities keeps
the concentration of phosphorus in the soil solution at a low value in
soil only a few centimeters away.
Addition of phosphate fertilizers in agriculture is never con-
tinued to the stage at which the ultimate capacity of soil to react
with phosphate is satisfied because such additions would be accom-
panied by unfavorable effects on plants. The maximum favorable
effects are achieved with comparatively small additions.
In terms of the concentration of phosphorus in solution, the con-
sequence of adding so much phosphate fertilizer that the soil is con-
verted to a phosphate bed would depend on the circumstances. One
solid figure—the value of 0.15 Mg of phosphorus per milliliter of
groundwater from the Phosphoria phosphorite formation of Garrison,
-------
0,1 mm
^* • -iwar-^
"••
FIG. 6.6. Cross section of a crystal of calcite showing a layer of
apatite developed on the surface when the calcite was immersed for 2
weeks in a 0.1-molar solution of tribasic sodium phosphate. (Ames,
1961.)
-------
CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 87
Montana—was recorded by White et al. (1963). This value is to be
regarded as a minimum that might be reached some years after appli-
cation of soluble phosphate had been discontinued. Higher concen-
trations would be expected as long as more soluble phosphates of the
type illustrated in Figure 6.3 remained.
DISTRIBUTION OF FERTILIZER PHOSPHORUS IN SOIL
Inorganic phosphorus
Most phosphate fertilizer is added to soil as a solid. The highly
soluble phosphates attract water from the surrounding soil and form
a saturated solution of the fertilizer, first in the fertilizer itself and
then in the surrounding soil as the solution is drawn into the soil by
capillarity. If the bulk soil is relatively dry, the soil around the ferti-
lizer is visibly wetted by the water that has accumulated (see Fig.
6.7). This process was described by Lehr et al. (1959) and Lindsay
and Stephenson (1959).
During outward movement of the solution the concentration of
phosphorus decreases because of reaction with the soil, exhaustion
of the soluble salts in the fertilizer, and dilution of the solution with
water in the soil. Eventually the concentration of the solution be-
comes low enough so that water is no longer drawn to any appreciable
extent from the surrounding soil. Within a few weeks the concen-
FIG. 6.7. Wetted zone of
soil around a granule of
concentrated superphos-
phate. The granule of fer-
tilizer was imbedded in
the smooth surface of a
dry soil, and the soil was
exposed to an atmosphere
saturated with water va-
por. The fertilizer took up
the water vapor, forming
a solution, and the solu-
tion moved into the soil by
capillarity.
-------
88 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
.
FIG. 6.8. Autoradiographs, showing distribution of radioactive phos-
phorus along water-saturated columns of soil 2 weeks after placement
of phosphate fertilizer at the lower end of the columns. The darker
areas represent higher concentrations of radioactive phosphorus. A —
Cecil sandy loam, KHsP^CX source; B = Elliott silt loam, Ca(H2P3-Qt)2
source; C = Fargo silty clay loam, KHsP^CX source; D = Miami silt loam,
KH2P32O4 source; E = Miami silt loam, Ca(H2P'?O4)2 source. (Bouldin and
Black, 1954.)
tration of phosphate in solution is so low that little further movement
occurs over a much longer time by either diffusion or mass movement
in moving water.
Generally, the concentration of total phosphorus in soil a few
weeks after addition of a soluble fertilizer is greatest at the site of, or
immediately adjacent to, the fertilizer and gradually decreases with
distance from the site of the fertilizer. The distribution pattern, how-
ever, is not always like this. Figure 6.8, for example, shows an in-
stance (autoradiograph E) in which there were two maxima in the
distribution of phosphorus with distance from the source. Bell (1968)
observed occurrences of bands of crystals of dibasic calcium phos-
phate dihydrate in glass-fiber filter paper imbedded in soil in which
phosphorus was slowly moving from a layer of soluble phosphate fer-
tilizer. The phenomenon of periodic precipitates or Liesegang rings
-------
CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 89
135 kg of P
added per hectare
20 40 60 80 100
Extractable phosphorus per gram of soil,jjg
FIG. 6.9. Extractable phosphorus at different depths in unfertilized
and phosphate-fertilized silt loam soil in Wisconsin. The soil received
a surface application of superphosphate equivalent to 135 kg of phos-
phorus per hectare on April 25 and was sampled on October 15 of
the same year for analysis by Truog's (1930) method. (Midgley, 1931.)
thus seems to have application in soil as well as in more homogeneous
media usually studied by chemists.
Results of three field experiments on movement of fertilizer
phosphorus in soil will be cited. Figure 6.9 shows an instance in
which the increase in extractable phosphorus in the soil in the
autumn following an early spring topdressing of superphosphate was
confined to the surface 6 cm. Results such as this are characteristic
of soils with moderate capacities to react rapidly with phosphate
added at high concentrations.
In the second experiment (Ozanne, 1962), the equivalent of
225 kg of P32-labeled superphosphate per hectare was broadcasted on
a fallow siliceous sand in the winter season in Western Australia.
After 38 days, during which a total of 23 cm of rain was received,
more than 50% of the labeled phosphorus had penetrated more than
1 meter below the surface of the soil. These results are characteristic
of soils that have little capacity of any kind for reaction with phos-
phate.
The third experiment (Fig. 6.10) shows the measurable accumu-
lation of phosphorus that occurred with time when repeated addi-
tions of superphosphate were made to a soil with moderate capacity
to react quickly with fertilizer phosphorus. The downward penetra-
tion was such that after 31 years the plots receiving 60 kg of phos-
phorus per hectare at presumably annual intervals could be clearly
distinguished from the control plots by .analyses of samples of soil
from the 40- to 60-cm depth. Plots receiving 180 kg could be clearly
-------
90 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
0
20
E
o
_- 40
o
a.60
-------
CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 91
than of phosphorus derived from inorganic fertilizers. The findings
have further relevance to attempts to use soil to remove phosphorus
from sewage or livestock wastes. The efficiency of soil for this pur-
pose may not be as great as it is for removing inorganic phosphorus.
Koelliker and Miner (1969) reported that water from drain tiles at a
depth cf 122 cm contained 0.5 ng of phosphorus per ml during a sea-
son in which the soil was irrigated with livestock wastewater contain-
ing 552 kg of phosphorus per hectare. The chemical oxygen demand
of the tile water was 37 jug/ml, which suggests that much of the rela-
tively high concentration of phosphorus was organic.
REFERENCES
Alekseeva, E. N. 1968. Migration of phosphorus down the soil pro-
file during long-term use of fertilizers. (Translated title.) Agrok-
himiya, 1968, No. 8, pp. 78-82.
Ames, L. L., Jr. 1961. Anion metasomatic replacement reactions.
Econ. Geol. 56:521-32.
Australia. 1956. Commonwealth Scientific and Industrial Research
Organization, Ann. Kept. 8:18-19.
Barber, S. A., Walker, J. M., and Vasey, E. H. 1962. Principles of ion
movement through the soil to the plant root. Trans. Joint Meet-
ing Com. IV &• V, Intern. Soc. Soil Sci. (New Zealand, 1962),
pp. 121-24.
Bell, L. C. 1968. Nature and transformation of crystalline phos-
phates produced by interaction of phosphate fertilizers with
slightly acid and alkaline soils. Ph.D. Thesis, Iowa State Univ.,
Ames.
Bouldin, D. R., and Black, C. A. 1954. Phosphorus diffusion in soils.
Soil Sci. Soc. Am. Proc. 18:255-59.
Clarke, F. W. 1924. The data of geochemistry. U.S. Geol. Survey
Bull. 770.
Cunningham, R. K. 1963. The effect of clearing a tropical forest soil.
/. Soil Sci. 14:334-45.
Dean, L. A. 1949. Fixation of soil phosphorus. Advan. Agron.
1:391-411.
Demolon, A., and Boischot, P. 1951. Reaction des sols a 1'apport de
phosphates solubles. Doses isodynames. Compt. Rend. Acad.
Sci. 233:509-12.
Dietz, R. S., Emery, K. O., and Shepard, F. P. 1942. Phosphorite de-
posits on the sea floor off southern California. Bull. Geol. Soc.
Am. 53:815-47.
Dyer B. 1902. Results of investigations on the Rothamsted soils.
USDA, Office of Exp. Sta. BuU. 106.
Fried, M., and Shapiro, R. E. 1956. Phosphate supply pattern of
various soils. Soil Sci. Soc. Am. Proc. 20:471-75.
Gautier, A. 1894. Sur un gisement de phosphates de chaux et d'alu-
mine contenant des especes rares ou nouvelles et sur la genese
des phosphates et nitres naturels. Ann. Mines (Ser. 9) 5:1-53.
Gottschalk, L. C. 1962. Effects of watershed protection measures on
reduction of erosion and sediment damages in the United States.
Intern. Assoc. Sci. Hydrol. Publ. 59, pp. 426-47.
Gunary, D. 1966. Pyrophosphate in soil; some physico-chemical
aspects. Nature 210:1297-98.
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92 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Haas, H. J., Grunes, D. L., and Reichman, G. A. 1961. Phosphorus
changes in Great Plains soils as influenced by cropping and
manure applications. Soil Sci. Soc. Am. Proc. 25:214-18.
Hannapel, R. J., Fuller, W. H., Bosma, S., and BuUock, J. S. 1964a.
Phosphorus movement in a calcareous soil: I. Predominance of
organic forms of phosphorus in phosphorus movement. Soil
Sci. 97:350-57.
Hannapel, R. J., Fuller, W. H., and Fox, R. H. 1964b. Phosphorus
movement in a calcareous soil: II. Soil rnicrobial activity and
organic phosphorus movement. Soil Sci. 97:421—27.
Hemwall, J. B. 1957. The fixation of phosphorus by soils. Advan.
Agron. 9:95-112.
Huddleston, J. H. 1969. Local soil-landscape relationships in eastern
Pottawattamie County, Iowa. Ph.D. Thesis, Iowa State Univ.,
Ames.
Huffman, E. O. 1968. The reactions of fertilizer phosphate with soils.
Outlook Agr. 5:202-7.
Jackman, R. H. 1964. Accumulation of organic matter in some New
Zealand soils under permanent pasture. I. Patterns of change
of organic carbon, nitrogen, sulphur, and phosphorus. New
Zealand J. Agr. Res. 7:445-71.
Juday, C., and Birge, E. A. 1931. A second report on the phosphorus
content of Wisconsin lake waters. Trans. Wis. Acad. Sci. Arts
Letters 26:353-82.
Koelliker, J. K, and Miner, J. R. 1969. Use of soil to treat anaerobic
lagoon effluent: renovation as a function of depth and applica-
tion rate. Paper presented at meeting of Am. Soc. Agr. Engrs.,
June 1969, Purdue Univ., West Lafayette, Ind.
Kohnke, H., Dreibelbis, F. R., and Davidson, J. M. 1940. A survey
and discussion of lysimeters and a bibliography on their con-
struction and performance. USDA Misc. Publ. 372.
Larsen, S. 1967. Soil phosphorus. Advan. Agron. 19:151-210.
Larsen, S., Gunary, D., and Devine, J. R. 1964. Stability of granular
dicalcium phosphate dihydrate in soil. Nature 204:1114.
Lehr, J. R., Brown, W. E., and Brown, E. H. 1959. Chemical be-
havior of monocalcium phosphate monohydrate in soils. Soil
Sci. Soc. Am. Proc. 23:3-7.
Lindsay, W. L.. and Stephenson, H. F. 1959. Nature of the reactions
of monocalcium phosphate monohydrate in soils: I. The solu-
tion that reacts with the soil. Soil Sci. Soc. Am. Proc. 23:12-18.
Ludecke, T. E. 1962. Formulation of a rational fertiliser programme
in tussock country. Proc. Neiv Zealand Grassland Assoc. 24:
29-41.
McAuliffe, C. D., Hall, N. S., Dean, L. A., and Hendricks, S. B. 1948.
Exchange reactions between phosphates and soils: hydroxylic
surfaces of soil minerals. Soil Sci. Soc. Am. Proc. 12:119-23.
McKelvey, V. E., Swanson, R. W., and Sheldon. R. P. 1953. The Per-
mian nhosphorite deposits of western United States. Congr.
Geol. Intern. Compt. Rend. 19th Sess. 11:45-64.
Mackenthun, K. M. 1965. Nitrogen and phosphorus in water. U.S.
Dept. Health, Education, and Welfare, Public Health Serv., Div.
Water Supply and Pollution Control.
Mattingly, G. E. G., and Talibudeen. O. 1967. Progress in the chem-
istrv of fertilizer and soil phosphorus. Topics Phosphorus Chem.
4:157-290.
Midgley, A. R. 1931. The movement and fixation of phosphates in
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CHAPTER 6 / SOIL AND FERTILIZER PHOSPHORUS / 93
relation to permanent pasture fertilization. /. Am. Soc. Agron.
23:788-99.
Morgan, M. F., and Jacobson, H. G. M. 1942. Soil and crop interre-
lations of various nitrogeneous fertilizers. Windsor lysimeter
series B. Conn. (New Haven) Agr. Exp. Sta. Bull. 458.
Nagelschmidt, G., and Nixon, H. L. 1944. Formation of apatite from
superphosphate in the soil. Nature 154:428-29.
Olsen, S. R., and Watanabe, F. S. 1957. A method to determine a
phosphorus adsorption maximum of soils as measured by the
Langmuir isotherm. Soil Sci. Soc. Am. Proc. 21:144-49.
Ozanne, P. G. 1962. Some nutritional problems characteristic of
sandy soils. Trans. Joint Meeting Com. IV & V, Intern. Soc. Soil
Sci. (New Zealand, 1962), pp. 139-43.
Pearson, R. W., and Simonson, R. W. 1939. Organic phosphorus in
seven Iowa soil profiles: distribution and amounts as compared
to organic carbon and nitrogen. Soil Sci. Soc. Am. Proc. 4:
162-67.
Pearson, R. W., Spry, R.5 and Pierre, W. H. 1940. The vertical distri-
bution of total and dilute acid-soluble phosphorus in twelve Iowa
soil profiles. J. Am. Soc. Agron. 32:683-96.
Pierre, W. H., and Parker, F. W. 1927. Soil phosphorus studies: II.
The concentration of organic and inorganic phosphorus in the
soil solution and soil extracts and the availability of the organic
phosphorus to plants. Soil Sci. 24:119-28.
Ponomareva, V. V., Rozhnova, T. A., and Sotnikova, N. S. 1968.
Lysimetric observations on the leaching of elements in podzolic
soils. Trans. 9th Intern. Congr. Soil Sci. (Australia) 1:155—64.
Scott, C. O. 1958. Sorption of orthophosphate and nonorthophos-
phate phosphorus by soils. Ph.D. Thesis, Iowa State Univ., Ames.
Stephenson, R. E., and Chapman, H. D. 1931. Phosphate penetration
in field soils. /. Am. Soc. Agron. 23:759-70.
Sylvester, R. O., and Seabloom, R. W. 1963. Quality and significance
of irrigation return flow. /. Irrig. Drain. Div., Proc. Am. Soc.
Civil Eng. 89, No. IR3, pp. 1-27.
Tamini, Y. F., Kanehiro, Y., and Sherman, G. D. 1964. Reactions of
ammonium phosphate with gibbsite and with montmorillonitic
and kaolinitic soils. Soil Sci. 98:249-55.
Taylor, A. W. 1967. Phosphorus and water pollution. /. Soil Water
Conserv. 22:228-31.
Teall, J. J. H. 1898. A phosphatized trachyte from Clipperton Atoll
(northern Pacific). Quart. J. Geol. Soc. London 54:230-32.
Thompson, E. J., Oliveira, A. L. F., Moser, U. S., and Black, C. A.
1960. Evaluation of laboratory indexes of absorption of soil
phosphorus by plants: II. Plant Soil 13:28-38.
Truog. E. 1930. The determination of readily available phosphorus
of soils. J. Am. Soc. Agron. 22:874-82.
Voelcker, A. 1874. On the composition of waters of land-drainage.
J. Roy. Agr. Soc. Engl, 2nd Ser. 10:132-65.
Weir, W. W. 1936. Soil science. Chicago: J. B. Lippincott.
White, D. E., Hem, J. D., and Waring, G A. 1963. Data of geochem-
istry, sixth edition. Chapter F. Chemical composition of sub-
surface waters. U.S. Geol. Survey Prof. Paper 440-F.
Wild, A. 1950. The retention of phosphate by soil. A review. J. Soil
Sci. 1:221-38.
. 1961. A pedological study of phosphorus in 12 soils derived
from granite. Australian J. Agr. Res. 12:286—99.
-------
CHAPTER SEVEN
SOURCES OF NITROGEN
WATER SUPPLIES
MARVIN C. GOLDBERG
ITROGEN, like silicon, carbon, and phosphorus, has the unique
ability to act as a Lewis acid or base. It has three p electrons, pre-
sumably unpaired, each capable of entering into chemical reaction.
Also, with all three valence electrons tied up, the inner 2s shell
electrons act as an electron pair donor and gave nitrogen its electro-
negative character in secondary amines and other such compounds.
Nitrogen is a gas at standard temperature and pressure; its density
is 0.81 g/ml. When combined in compounds, nitrogen exhibits
oxidation states from —3 to +5. The elemental state is extremely
electronegative with a value of 3 on the Pauling scale. Only a few
of the nonmetals, for example, O, F, and Cl, have electronegativity
of equal or greater value.
Nitrogen concentration in the dry atmosphere of the earth is
757.4 g/cm2 of earth's surface, according to Hutchinson (1954). The
total atmospheric mass is 38.65 geograms. (A geogram is 1020
grams.) The mass of water in the hydrosphere is 14,000 geograms.
The amount of dissolved nitrogen is 0.26 geograms, or equivalent to
5.2 g/cm2 of the earth's surface. The average nitrogen concentration
in igneous rocks is about 0.005% by weight. It occurs in the form of
ammonium substituted for potassium in mineral lattices.
CHEMISTRY OF NITROGEN IN WATER
Ammonia and other reduced forms such as nitrous oxide, ni-
trites, etc., are oxidized by nitrifying bacteria to nitrates in water.
Organic nitrogen is primarily formed and degraded by biological ac-
tion. Common species of organic nitrogen are proteins, protein deriva-
tives, purines, pyrimidines, and urea. Some of these materials are
readily degradable and some are not. Pyrimidines and purines are
important components of nucleotides and eventually may end up as
genetic components such as DNA and RNA. Urea, on the other hand,
MAHVIN C. GOLDBERG is Research Hydrologist, U.S. Geological Survey,
Denver Federal Center, Denver.
Publication authorized by the Director, U.S. Geological Survey.
94
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 95
is a decomposition product of proteins or amino acids and is readily
hydrolyzed enzymatically in natural waters into ammonia and car-
bon dioxide. Urea is a highly available form of nitrogen for biological
synthesis.
Another species of bound nitrogen in water is the solute from
geochemical organic deposits. Most of this type of material, which re-
mains undissolved, does not enter the nitrogen cycle. Usually the non-
reactive character of geo-organic nitrogen is due to adsorption onto
clay minerals or formation in complex forms which are polymeric and
exist in water as polyelectrolytes. Only about 5 to 10% of this ma-
terial is in the form of nucleic acids, 30 to 40% is in the form of
proteins, and 10 to 15% is amino sugars. The remainder has been
uncharacterized. The majority of soluble organic nitrogen in lakes
is present in the form of amino groups.
For each 15 atoms of available nitrogen in water, there are 510
atoms of dissolved molecular nitrogen and a relatively unlimited
supply of elemental nitrogen both in the atmosphere and the sedi-
ments. Hence, nitrogen becomes a limiting nutrient in water bodies
only because of the slow rate at which atmospheric nitrogen is fixed
or the slow rate at which organic nitrogen deposits are degraded.
OBJECT
Water supplies can be categorized as surface waters or ground-
waters. This discussion will examine representative studies of ni-
trate entrance to both types of water supplies, with summaries of
some of the many laboratory and field studies described in the cur-
rent literature. As the literature is voluminous, only some exemplary
studies are mentioned.
ENTRANCE OF NITROGEN INTO WATER
Mechanisms for the introduction of various fixed forms of ni-
trogen into water are categorized as nitrogen fixation from the air,
ammonia entrance from "rainout," entrance of organic nitrogen from
decomposing plants and animals, and land drainage. Water solu-
tions usually contain nitrogen in either organic or ionic form. Am-
monium, nitrite, and nitrate are the most common ionic forms of
nitrogen found in water. In water itself, as the nitrogen cycle
illustrates, proteinaceous material is decomposed by bacterial action.
The inorganic ions which result from this decomposition are in turn
used as nutrients to form new cell material. The forms of the new
cell material are controlled by the environmental conditions imposed
upon the biological systems involved. Grill and Richards (1964)
examined nutrient regeneration from phytoplankton and observed
that at the end of an experiment dealing with phytoplankton de-
composition, 33% of the total nitrogen was ammonia, 39% was in
particulate matter, and 28% was in dissolved organic compounds.
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96 / Part 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
NITROGEN SOURCES IN WATER SUPPLIES
A catalogue of some sources of nitrogen in water supplies would
include:
Agriculture
Irrigation
Rural runoff
Tile drainage
Animals
Atmospheric
Air pollutants from industrial sources
Pollen
Precipitation
Feedlots
Fertilizer
Geologic
Caves
Minerals
Industrial wastes
Lake sediments
Pond water
Rural waste
Barnyards
Feeds
Privies
Storm water
Topsoil
Urban waste
Leaking sewers
Sanitary landfills
Septic tanks
Sewage
Sludge lagoons
Waste stabilization ponds
Water treatment plants
ATMOSPHERIC PRECIPITATION AS A SOURCE OF NlTROGSi J
Precipitation might be the most important single source of ni-
trogen in surface waters (Feth, 1966), and thus it would also be avi
important source of nitrogen in groundwater.
Most of the nitrogen in the atmosphere is in the molecular form
of N2; however, there are small amounts of ammonia as well as
various oxides of nitrogen and their hydration products, such as
nitric acid. Much atmospheric ammonia is attributed to industrial
air pollution. Additional sources are released from soil decomposi-
tion products and photochemical reactions occurring in the strato-
sphere. The most abundant oxide of nitrogen is probably N2O.} pro-
duced by internal combustion engines. Ion molecule reactions which
occur in the stratosphere and upper ionosphere account for forma-
tion of nitrogen molecules other than N2.
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Chapter 7 / SOURCES OF NITROGEN IN WATER / 97
Stable aerosols composed of ammonium sulfate and ammonium
persulfate occur at altitudes between 15 and 25 kilometers above the
earth. Particles are in a constant condition of fallout from the
stratosphere to lower layers of the atmosphere where they are in-
corporated into falling rain or snow. In a study by Junge (1968), it
was reported that nitrate and ammonium concentrations in rainwater
were low near coastlines. During April 1958 to March 1959 about
59% of total inorganic nitrogen in rainwater at Yangambi, Bel-
gian Congo, was ammoniacal nitrogen (Meyer and Pampfer, 1959).
Nitrous nitrogen did not exceed 3% of the nitric nitrogen. Of special
interest is the fact that examination of individual downpours showed
that the smaller the downpour, the higher the concentration of ni-
trogen, especially ammoniacal nitrogen. Matheson (1951) reports
6.5 kg nitrogen per hectare per year as accumulate nitrogen fall
contained in precipitation and atmospheric sediments collected at
Hamilton, Ontario, with 61% of the total nitrogen collected on 25%
of the days when precipitation occurred. The balance is due solely
to sedimentation of dust. Fifty-six percent of the total was ammonia
nitrogen. In a New Zealand experiment (Miller, 1961) it was observed
that total nitrogen collected at the Taita Experimental Station from
rainwater was double the concentration of inorganic and aluminoid
nitrogen. Contributions from rainwater to nitrogen in soil would
probably be not less than 3.36 kg/ha/yr.
Feth (1967) lists tables of data indicating bulk precipitation of
nitrate in the Mojave Desert Region, California, between March 1965
and March 1966. Values for nitrate nitrogen ranged from a trace to
as high as 16 mg/1 of rain, depending upon time of year and location.
Wind-borne sources of nitrogen also exist. For example,
McGauhey et al. (1963) have shown the amount of nitrogen con-
tributed by pollen may be as high as 2 to 5 kg/ha/yr in a forested
area.
GEOLOGICAL SOURCES OF NITROGEN
Examples of geological sources of nitrate are the estimated 227
teragrams of nitrate of soda on the plateau of Tarapaca in Chili and
the significant amounts of nitrate in the Amargosa Valley, Inyo
County, California. Nitrate deposits have been found in soils or
geologic formations in all of the 11 western states. Most of the states
in the Ozark and Appalachian plateaus have natural nitrate accumu-
lations in caves. Other geological sources of nitrate are igneous
rocks, coal, peat beds and muck soils, cave deposits, caliche deposits,
and playa deposits. In addition, all the world's organic matter, both
living and dead, plus that in sedimentary rocks, are potential sources
of nitrogen.
According to notes on the Conference on Nitrogen Chemistry
held by the U.S. Geological Survey in Menlo Park, California (1965),
fixed nitrogen in rocks may amount to a total 50 times as great as
the amount of fixed nitrogen in the atmosphere. Rocks, however,
are not a ready source of nitrogen because of access problems,
-------
98 / Part 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
attributed to small exposed surfaces. Only limited zones near the
surface are in position to yield their nitrogen freely to circulating
air and water. They can be considered, however, as groundv/ater
nitrate sources under certain circumstances (Smith, 1967)—for ex-
ample, in those localities where conditions have altered the geologic
strata in such manner that there is collapse of cavern roofs or burial
of ancient playa deposits which become geographically placed in
the zone of saturation.
Organic-rich shales can also be a source of nitrogen. It has
been reported that in sedimentary rocks, concentrations as high as
600 mg/kg dry weight of nitrogen may be present. Miocene shale
from the Los Angeles Basin, California, can contain up to 8,600
mg/kg nitrogen.
The largest geologic concentrations of nitrogen seem to be
present in the younger rocks; they are highest in clay, slate, and
argillite, and generally low in metamorphic rocks. Water released
during metamorphism tends to be high in ammonia. Igneous and
sedimentary rocks may contain nitrogen in amounts ranging from
40 to 500 mg/kg, but organic shales contain nitrogen in much higher
concentrations.
NITROGEN IN LAKES
Nitrogen from Lake Sediments
In 14 samples from the upper 10 cm of Lake Tahoe sediments
analyzed by the Kjeldahl method, nitrogen concentrations ranged
from 0.06 to 16.6 mg/g dry weight and carbon nitrogen ratios from
3.7 to 28.4 (McGauhey et al., 1963).
Decomposition Processes in a Lake as a Source of Nitrogen
Koyama and Tomino (1967) studied the mineralization of nitro-
gen-containing materials in a lake. Their results are typical of many
such studies and show primarily (1) that during the early stages of
the stagnation period, nitrogen fixation is generally more active than
denitrification. Denitrificarion gradually exceeds nitrogen fixation
with progressive stagnation and (2) at the end of the stagnation
period, the amount of denitrified nitrogen is large when compared
with other mineralized nitrogen compounds. Denitrification is the
dominant process determining nitrogen metabolism in the lake water.
The ratio of mineralized carbon to nitrogen at the end of the stagna-
tion period is 3.5, considerably smaller than the value for plankton
of 5.7. Mineralization rates of carbon and nitrogen in the organic
detritus of the lake studied were 51% per year and 76% per year,
respectively.
Nitrate Metabolism in Lakes
The following regime has developed in Sanctuary Lake, Penn-
sylvania (Dugdale and Dugdale, 1965): (1) a spring bloom when
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 99
ammonia nitrogen, nitrate nitrogen, and molecular nitrogen are
assimilated strongly, in that order of importance; (2) a midsummer
period when weak assimilation of ammonia nitrogen and molecular
nitrogen, but not nitrate nitrogen, occurs; and (3) a fall bloom with
intense nitrogen fixation and some ammonia nitrogen uptake, but
characterized by a low nitrate nitrogen activity. Nitrogen fixation
and ammonia nitrogen uptake appear to proceed at the same time,
although ammonia uptake dominates in the spring and nitrogen fixa-
tion dominates in the fall.
Biogenic interactions affect nitrogen sources in waste—for ex-
ample, fixed nitrogen entering a reservoir is synthesized into the
biomass as protein and liberated upon death of the biological entity.
As much as 40% is released to the aqueous environment, some
diffuses to the surface and escapes as a volatile gas, some is denitri-
fied (gcing from the +5 oxidation state to —3) and some is per-
manently incorporated into the bed sediments.
Examination of a nitrogen cycle (Ehrlich and Slack, 1969) re-
vealed that nitrogen assimilation in a laboratory study, where the
sole nitrogen source was a stream of calcium nitrate, followed the
characteristic pattern. The nitrogen was assimilated by plant life,
in this case algae, with slight demtrification occurring at high nitrate
concentrations. The organic nitrogen was converted to ammonia by
proteolytic bacteria, with the possible escape of some ammonia. The
ammonia from the organic compounds was partly assimilated by
algae and partly nitrified by bacteria. The nitrate, of bacterial
origin, was assimilated by algae. Nitrification apparently was not
of major importance in converting organic nitrogen to algal biomass.
Analysis of surface and subsurface samples from western Lake
Superior (Putnam and Olsen, 1959) showed that ammonia nitrogen
was present in trace amounts only, usually less than 0.1 mg/1. It
was found that the range of organic nitrogen during the year was
from 0.08 mg/1 in the hypolimnion to 0.28 mg/1 at the surface.
The b"lk of nitrogen in the lake existed in the form of nitrate and
ranged from 0.93 mg/1 at the surface to 1.15 mg/1 in the hypo-
limnion. Nitrite was practically indetectable. Waters that entered
Lake Superior from its tributary streams contained very little free
ammonia. Nitrate concentrations in the rivers were lower than that
observed in the lake and varied from 0.16 mg/1 to 0.47 mg/1. Ni-
trite was either absent or present only in trace amounts. In a second
publication (Putnam and Olsen, 1960) it was stated that nitrate-
nitrogen concentrations were directly related to the depth of the
sample and in no case was the concentration lower in the deeper
water layers than near the surface. As expected, nitrate nitrogen
in all tributary streams except one was considerably lower than that
observed in the lake. In August the nitrate nitrogen range was 0.01
to 0.44 mg/1.
AGRICULTURAL SOURCES OF NITROGEN IN WATER
Agricultural sources of nitrogen result primarily from organic
and inorganic materials added to soils for crop nutrition. Movement
-------
TOO / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
TABLE 7.1. Estimate of nutrient contributions from various sources.
Nitrogen
Source
Domestic waste ....
Industrial waste ....
Rural runoff:
Agricultural land .
Nonagricultural
land
Farm animal waste .
Urban runoff
Rainfall*
Pounds
per year
(millions)
1,100-1,600
>1,000
1,500-15,000
400-1,900
>1,000
110-1,100
30-590
Usual
concentra-
tion in
discharge
(mg/l)
18-20
0-10,000
1-70
0.1-0.5
t
1-10
0.1-2.0
Phosphorus
Pounds
per year
(millions)
200-500
T
120-1,200
150-750
t
11-170
3-9
Usual
concentra-
tion in
discharge
(mg/l)
3.5-9.0
t
0.05-1.1
0.04-0.2
j.
0.1-1.5
0.01-0.03
Source: Task Group 2610-P Report (1967). Reprinted from the March 1967
issue of J. Am. Water Works Assoc. Copyright 1967 by the Am. Water
Works Assoc., Inc.
* Considers rainfall contributed directly to water surface.
t Insufficient data available to make estimate.
of these materials has been traced from their soil origin to entrance
into surface and groundwater supplies. Several of the following
studies indicate the fate of agricultural nitrogen-containing materials
after entrance into the environment.
A review paper (Smith, 1967) describes the use of fertilizer salts
to supplement nitrogen in soils. This nitrate source feeds vegetation,
is lost to the atmosphere by denitrification, and is removed from the
soil by erosion and leaching. Organic-matter nitrogen lost from soils
is usually attributed to mineralization.
Estimate of Nutrient Contributions from Various Sources
Table 7.1 characterizes nitrate sources in water. The relative
magnitude of runoff from agricultural land is noticeably large.
Rural Runoff as a Nitrogen Source
Approximately 742 million hectares of rural land in the United
States produce runoff. Major factors in rural runoff are amount of
water applied and land use. For example (McGuinness et al., 1960),
runoff is greatest for a corn crop, somewhat less for wheat, and
least when the land is in meadow. The mean concentration given in
milligrams per liter of total nitrogen constituents per storm event
with land planted to wheat varies between 6 and 9 (Weidner et al.,
1969). These data are losses from a watershed varying in agricultural
use.
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Chapter 7 / SOURCES OF NITROGEN IN WATER / 101
Agricultural drainage waters contain nitrogen concentrations
ranging from 1 to 60 mg/1, mostly in the form of nitrate. Sediment
suspended in flowing water may carry relatively high amounts of
ammonium nitrogen as well as particulate organic nitrogen. Dis-
tribution of nitrogen in river waters in the United States ranges
roughly from 0.1 mg/1 to 3.0 mg/1.
Annual average nitrogen loss from a watershed drainage of an
apple orchard in Ripley, Ohio, was 1.0 kg total nitrogen per hectare.
The mean-runoff nitrogen concentration per storm for the apple
orchard was 4.9 mg/1 total nitrogen. The results of this work indi-
cate that rural runoff is a factor in stream pollution and must be
considered as a source of nitrogen in water supplies.
Timmons et al. (1968) have conducted a definitive study on
the loss of crop nutrients through runoff. As can be seen from Table
7.2, a study of the Barnes-Aastad Soil, Water, and Conservation Re-
search Association farm near Morris, Minnesota, showed 29.1 kg/ha
nitrogen loss in the year 1966, with a high of 9.65 cm of runoff, and
100.7 kg/ha nitrogen loss in 1967, with a high of 11.76 annual cen-
timeters of runoff. Nitrate accounted for the majority of the nitrogen
loss and in 1966 was 0.89 and in 1967, 2.9 kg/ha. '
UREA MATERIALS
Several materials used as agricultural fertilizers are salts of
nitrogen. One of the materials used commercially in large quantities
is ureaform. When evaluated as a nitrogen-loading material in soils,
TABLE 7.2. Annual nutrient loss for two seasons for the natural-rainfall ero-
sion plots.
Avg
Annual
Kilograms
Pei-
Cropping Hectare
Treatments Soil Loss
Fallow
Corn-continuous . .
Corn-rotation ....
Oats-rotation ....
Hav-rotation
8,518.0
807.0
426.0
22.4
0.0
Avg
Annual
Centi-
meters
Runoff
3966
9.65
2.31
5.20
0.51
8.66
Avg Kg per Hectare Nutrient Loss
Total
N*
29.1
4.48
2.24
0.11
0.34
NH.-N
0.33
0.11
<0.11
0.0
0.0
NO.N
0.90
0.11
0.33
<0.11
0.11
P
0.04
0.11
0.11
0.0
0.11
K
2.0
0.56
0.67
0^90
Fallow
Corn-continuous . .
Corn-rotation
Oats-rotation ....
Hay-rotation . ...
23,044
7,039
1,389
2,286
0
0
.0
0
.0
0
1967
11.76
7.56
5.96
5.30
9.72
100
21
7
10
6
.8
.5
.5
.5
.4
0
0
0
0,
0.
.22
.34
.11
.11
,0
0
0
0
0
0
.54
.90
.08
.18
.04
2.9
0.04
0.11
0.11
0.33
5.1
1.3
0.67
0.67
5.8
Source: Timmons et al. (1968). Reprinted with permission.
* Excludes NH4- and NO.-N.
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102 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
it was found to be relatively long lived (about 1 year) and stable
(Brown and Volk, 1966). Losses did occur once the nitrogen entered
the soil biological cycle. If water-soluble nonurea portions of urea-
form were incubated anaerobicaliy with soil, appreciable quantities
of hydrogen were produced. Simultaneously NH,NOo was evaluated
and in studies where the initial rate of application was 168 kg cf
nitrogen per hectare it was found that 2 to 5% of the ammonium
nitrate was in the soil to a depth of 0 to 15 cm. Ureaform was found
in amounts of 18 to 249c in soil from 0 to 15 cm in depth. Of the
1 68 kg nitrogen per hectare application it was noted that the percent
excess was 9.091 of ammonium nitrogen and 8.973 of nitrate nitro-
gen, whereas the ureaform excess produced was 9.907 ureaform
nitrogen.
The loss of urea nitrogen on leaching as traced by lysimcter
studies was examined (Overrein, 1968) during a 12-week experi-
mental period, and it was shown that at urea application rates of
less than 250 kg of nitrogen per hectare, loss was slight. At appli-
cation rates of 1.000 kg of urea nitrogen per hectare, treatment was
o o i '
followed by a leaching loss equivalent to 5rc of the added fertilizer
nitrogen. The volatile ammonia gas loss was also characterised.
The highest total of accumulated loss of ammonia was equal to
3.5r' of the added urea nitrogen. No gaseous nitrogen oxides were
produced. Trace amounts of tagged molecular nitrogen were re-
covered in the atmosphere above lysimeters receiving the urea nitro-
gen during tests in which the higher application rate was used.
NITRATE AND AMMONIUM MATERIALS
Ammonium nitrate and urea differ considerably in the extent
to which they are adsorbed by the soil. It is reasonable to expect
that they vary in their susceptibility to loss from the soil by leaching
into surface runoff water. Urea, however, is hydrolyzed to ammonium
ion and ammonium ion is nitrified to nitrate in soils. A time interval,
therefore, must be allowed between fertilizer application and occur-
rence of rainfall before computing nitrate runoff into surface waters.
Such a study was conducted (Moe et al., 1968) and the ammonium
nitrogen losses from urea-treated plots were approximately equal to
those from the ammonium-nitrate-treated plots during artificial rain-
fall applications. In a second set of artificial rainfall applications,
losses of ammonium nitrogen averaged 40% less. It was concluded
that the ammonium nitrogen is less susceptible to runoff loss in the
urea-treated plots than in the ammonium-nitrate-treated plots. An
explanation is that ammonium nitrate, because of its high ionization.
wculd be adsorbed and held near the surface of the soil. A non-
ionized urea would be carried farther down into the soil with the first
increment of rainfall and would be less subject to surface runoff loss.
It was found that urea is rapidly hydrolyzed to ammonia in the
soil: the only measurable amounts of urea occurred in the runoff from
socl plots and resulted from the direct washing of urea from the sur-
face vegetation. Total nitrogen losses from all plots ranged between
2.4 and 12.7% . These results are very similar to those of Mce et al.
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 103
(1968). As a general conclusion, the amount of nitrogen in the run-
off water from soils treated in this manner would not contribute
appreciably to nitrate pollution of surface-water resources.
White et al. (1967) studied movement of NH,NO., applied on
a soil surface at the concentration of 224 kg/ha. Six and three-tenths
centimeters of artificial rainfall were applied in a 2-hour period,
during which the runoff from fallow soil was 4.9 mg/1 and from sod
2.1 mg/l. After a few moments, most of the soluble nitrogen moved
into the soil and was inaccessible to erosion processes.
On the southern high plains (Lotspeich et al., 1969) estimates
are that 0.2% of the fertilizer nitrogen applied is found in surface-
water runoff. In nearly all the playas of the southern high plains,
the nitrate content is less than 1.0 mg/1, revealing the fact that ni-
trogen fertilizer applied to the farmland adds little nitrate to the sur-
face water.
A clue to nitrogen runoff from soil, resulting in enrichment of ni-
trogen in water, may be discovered in the data of Pratt et al. (1967).
It was found that the ratio of nitrogen removal to total crop yield
was higher with Ca(NO;J)o treatment than with ammonium sources.
The largest amount of nitrogen removed by drainage water as well
as the highest nitrogen depletion occurred in a soil relatively high
in organic content. Lack of organic matter may explain low nitrate
runoff on the southern high plains.
A study of 82,029 irrigated hectares (Carter et al., 1969) illus-
trated that subsurface drainage water contains more nitrate nitro-
gen than does the irrigation w*ater. but concentration rarely exceeds
5.0 mg/1 of nitrogen. Concentrations of nitrogen in surface drainage
waters are only slightly higher than concentrations in the irrigation
water.
A study in Britain demonstrated that the amount of nitrogenous
fertilizers applied to agricultural land has doubled in the last 10 years.
Land drainage has been shown to contribute much inorganic nitrogen
to rivers. In the Great Ouse River (Owens and Wood, 1968) sewage
effluents contributed a small proportion of the total concentration of
nitrogen, silicon, chloride, and sulfate; however, the bulk of the
phosphorus could be attributed to the effluent sources. Table 7.3
TABLE 7.3. Ranges of some selected nutrients in sewage effluents and land
drainage entering the Great Ouse: Concentrations in the river
water are also included.
Nutrient
Carbon (soluble)
Arnmoniurn-N • ...
Nitrate-N
NitrHe-N
Organic-N
Potassium
Total soluble phosphorus . .
Silicon
Sewage
Effluent
(mg/l)
6.7-24.0
00-48.0
0.0-35.0
0.0-14.5
0.0-13.6
. 16.0-32.0
3.0-14.0
1.9-11.0
Land
Drainage
(mg/l)
2.8-8.0
0.0-0.5
5.5_99.4
0.01-0.1
0.3-0.9
6.0-16.5
0.02-0.3
0.7-5.0
River
Water
(mg/l)
3 5 12 4
0098
3 0-14 9
0 01-04
0.0-2 9
6.8-9 0
0.17-0.73
0.07-5 0
Source: Owens and Wood (1968). Reprinted with permission from M.
Owens. Copyright 1968, Pergamon Publ. Co.
-------
104 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
(Owens and Wood, 1968) lists the nutrients entering the Great Ouse
River yearly and their sources.
Figure 7.1 shows the estimated total quantity of nutrients sup-
plied by sewage effluents in comparison with the total load of nu-
trients in the river. Only about 10% of the nitrogen in the river
could be accounted for by the amounts discharged in sewage efflu-
ents. It was assumed that increase in river flow between the influent
streams and the downstream limit of the reach, other than that from
the sewage effluent, was derived from land drainage and that this
land drainage would have the same average concentration of nu-
trients as the land drain sampled. Estimated nutrient loads are
between 1.0 and 2.3 times greater than those actually determined.
Hence, the assumption that the increase in load results from land
drainage may be in error.
About 3.15 x 106 kg of nitrogen were carried by the Great Ouse
River in 1966. If all of the material flowing down the river were
derived from land drainage, the flows of nitrogen per unit of catch-
ment area would be 18.5. The amount of nitrogen applied per unit
30C
700
FIG. 7.1. Nutrient bal-
ance in Great Ouse, March
1967. (Owens and Wood,
1968. Reprinted with per-
mission from M. Wood.)
500
500
N - Mass Flow of Nutrients in River
N = Accumulated Flow of Nutrients
From Sewage Effluents
z
llJ
0
g 200
J
100
135 140 145 150 155 160 165
CATCHMENT AREA (thousand ha)
170
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 105
area in the Ouse basin, according to statistics supplied by the Min-
istry of Agriculture, Fisheries and Food, was 65 kg/ha.
TIME VARIATION
One study (Olsen et al., 1969) related that more leaching of
nitrate nitrogen occurred between fall and spring than during the
growing season and more under fallow than cropped conditions.
TILE DRAINAGE EFFLUENT
Effluents from a tile drainage system in irrigated areas in the
San Joaquin Valley of California showed that initial tile effluent
frcm a previously unirrigated, noncropped area had a nitrogen con-
centration of 1.0 mg/1. Another system that had been planted to
alfalfa had a low discharge over a year's period and yielded a range
of nitrogen between 2.0 and 14.3 mg/1. In systems where high
rates of nitrogen fertilizer were applied, the concentrations ranged
up to 62.4 mg/1. Concentrations of nitrate in all systems ranged
from 1.8 to 62.4 mg/1, with a weighted average of 25.1 (Johnston
et al., 1969).
Nitrogen can be carried directly into surface drains with tail-
water from fields where fertilizer is being applied in the irrigation
water. In addition, nitrogen can also come from nonirrigated agri-
cultural land. A further source of nitrogen is soil from erosion,
with resulting increase in sediment load, plant nutrients, and pesti-
cides. Soil nitrogen is sporadically released to water, such release
being produced and greatly influenced by intensity of precipitation.
It was shown that in sand columns (Preul and Schroepfer, 1968)
the breakthrough curve for ammonium nitrogen occurs between 0.5
and 1.0 in units of throughput volume per column weight measured
in liters per kilogram of soil. Flow rates varied from 200 to 1,170
ml/day, nH ranged from 7.1 to 7.6, and nitrogen absorntion ranged
from 24.7 to 126.0 /j.g/g of ammonium nitrogen, at equilibrium. Dis-
charge velocities were approximately 4.93 cm/day at flow rates of
1,000 ml/day. The conclusions of this study are that movement of
nitrogen in soils is controlled by adsorption and biological action,
and that where nitrogen is in a nitrate form at the pH of usual
wastewaters there is no impairment to nitrogen movement. Biological
interference is minimized under flow conditions with limited oxygen
tension. These results indicate a minimal vertical flow. In the study
indicated, the major part of nitrification was restricted to within 0.61
meter of the surface. The possibility of lateral flow, however, would
tend to move nitrogen into surface waters. Leachates of nitrogen
(NH4NOo)-treated soil (Krause and Batsch, 1968) contained 4 to 7
mg/1 ammonium nitrogen; the soil lost 88% of its treated nitrogen
between September and December. Untreated soils slowly lost ni-
trate nitrogen.
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106 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
IRRIGATION RETURN FLOW
A study of irrigation return flow in the Yakima River Basin,
Washington (Sylvester and Seabloom, 1963), was made for an irri-
gated area of 151,870 hectares during an irrigation season extend-
ing from April through September. Average water diversion was
20,000 m3 per hectare per year of which approximately 5,240 m3 was
applied to land; the remainder was lost in canal seepage and canal
evaporation wastage.
It was established that the evapotranspiration loss in the irriga-
tion water return would result in a salt concentration of 1.7. The
nitrate content of the return due to evapotranspiration, leaching,
and ion exchange was 10 times greater than in the applied water.
Removal of 37 kg/ha of nitrate resulted from irrigation leaching.
Salts and sediments are of great concern to water users (Peter-
son et al., 1969). Salt and silt create the most difficult problems to
irrigation, agriculture, and subsequent users of return flow. Under
certain conditions, however, animal waste, plant nutrient, and toxic
elements become equally important.
Nitrogen Movement in Soils
In a leaching experiment (Sinha and Prasad, 1967), urea was
found to be distributed mainly within the top 10 centimeters of the
soil column and very little of it leached down below this depth.
Retention of urea in soils appears to be due to its conversion to
ammoniacal form.
In a typical situation in the San Joaquin Valley from 1962 to
1966, it was found that the subsurface drainage water of fields
irrigated with water containing 1.7 mg/1 of nitrate nitrogen had
nitrate levels averaging 44.5 mg/1. Fertilization consisted of adding
187 kg nitrate nitrogen per hectare per year (Doneen, 1968).
It was also found that nitrate concentrations of drainage waters
from different areas generally paralleled the amount of fertilizer
nitrogen.
LATERAL MOVEMENT OF NITRATES
Smith (1967) cites data to illustrate the diminishing concentra-
tion of nitrates 61 to 91 meters from the source origin. A second
conclusion was that at the site under observation, leaching of fer-
tilizer nitrogen was relatively insignificant in comparison to other
sources.
FATE OF NITRATE NITROGEN IN TROPICAL SOILS
Macrae et al. (1968) in a study of submergence of tropical soils
determined that considerable proportions of applied nitrate nitrogen
had been immobilized into the soil organic fraction. Six Philippine
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 107
soils were used in the study to trace the fate of added nitrate nitrogen
after submergence.
Occurrence of Nitrates in Wei! Water
Shallow wells frequently contain greater nitrate concentrations
than deep wells. As has been shown by many workers, this may be a
result of improper well construction. Shallow wells and deep wells
can be polluted by nitrates, either leached from the aquifer or trans-
mitted to the aquifer by percolating waters. Sources of nitrogen in
deep wells are strata through old wells which have been abandoned,
pumped wells with rusted or perforated casings, improper sewage
and waste disposal, natural sinkholes, and river valleys recharge.
Nitrate levels fluctuate in wells on an annual basis.
A survey of nitrates in private water supplies in Morgan County,
Missouri, made by the Missouri Division of Health (Inglish, 1967)
showed that in 157 well waters tested, 40 contained no nitrate, 27
contained less than 1 mg/1, 44 contained between 1 and 20 mg/1,
20 contained between 20 and 45 mg/1, and 23 contained over 45
mg/1, with the highest value being 200 mg/1. Of these wells only
13 were cased to a depth of 30.5 meters or more and only 4 were free
of nitrate.
Nitrates in Groundwater Supplies
Appearance of excessively high amounts of nitrates in ground-
waters has been considered an indication of wastewater infiltration
into the supply. The wastewater may originate from septic tank
effluents, waste stabilization ponds, waste treatment plant effluents,
sludge lagoons, sanitary landfills, privies, barnyards, leaking sewers,
irrigation systems, and similar sources. Of course, these sources
carry public health implications. Comly (1945), Metzler (1950), and
Whitehead and Moxon (1952) have reported on the hazard of nitrogen
in water supplies. One manifestation of nitrates is the disease infant
methemoglobinemia. Livestock, chiefly hogs and cattle, are affected
adversely and exhibit poor growth characteristics. Nitrates can cause
gastroenteritis and diarrhea. In some instances, high nitrogen levels
in water can be lethal.
LIMITS OF NITROGEN IN WATER SUPPLIES
Forty-five mg/1 nitrate is the upper limit set by the U.S. Public
Health Service for city potable water supplies.
Some of the most immediate sources of nitrate and nitrite in
groundwaters are domestic sewage effluents, fertilizers, and wastes
from corrals. Mean concentrations of nitrate nitrogen from wells in
nonirrigated and irrigated regions of southern Oahu were 1 ± 0.22
mg/1 and 8.2 ± 2.4 mg/1, respectively (Mink, 1962). Mink attributed
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108 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
TABLE 7.4. Characterization of waters in the San Luis Valley, Colorado.
Water Characteristics
Rio Grande River Aquifer Characteristics
Total dissolved solids 41-120 mg/1 Unconfined to depth of 100 feet
Character Ca(HCO3)2 Wells are 35-100 feet in depth
pH 6.7-7.4 Total dissolved solids 100-400 mg/1
pH 7.0-7.8
Source: R. K. Glanzman and J. M. Klein. (Data to be published.) Private
communication.
this difference to percolation of nitrate materials previously added
to the system in the form of fertilizer.
A study made by the U.S. Geological Survey in the San Luis
Valley, Colorado, conducted by Glanzman and Klein1 of the Colorado
District found relatively high nitrate concentrations in wells at depths
of 11 to 30 meters.
The San Luis Valley has an arid high-altitude climate with 15
to 18 cm of rainfall annually. The Rio Grande is the major surface-
water source; its nitrate concentration ranges from 0.0 to 2.3 mg/1.
Table 7.4 gives the other characteristics. Soil characteristics are given
in Table 7.5.
Nitrogen application on the surface soils of San Luis Valley was
112 kg of nitrogen per hectare per year in the form of ammonium
sulfate. The nitrogen was applied by disking, banding, or sideband-
ing. These treatments were followed by copious applications of water.
Considering that the water table was within 30 cm of the surface,
it is likely that the high nitrogen content in wells was due to percola-
tion from surface applications and especially from irrigation ditches.
which are used to disperse the fertilizer in liquid form to soil sur-
faces.
Figure 7.2 is a contour map showing concentrations of nitrate
in the San Luis Valley. The irrigation ditches correspond to the lines
of high nitrate concentration. It is reasonable to conclude that some
of the nitrate infiltration is coincident with the surface route of the
main irrigation ditches.
The fertilization practices followed in this valley incorporate
large amounts of ammonium sulfate, applied as dissolved solute, in
irrigation water. Considering the high water table and the general
lack of other nitrogen sources such as feedlots, septic tanks, and
sewage-processing tanks, it appears that in this case the nitrogen
source is inorganic fertilizer.
ANIMAL VARIATION
Nitrates tend to accumulate at the top of a groundwater column.
As leaching through a soil is a function of physical parameters, such
1. Glanzman, R. K., and Klein, J. M. (Data to be published.) Private
communication.
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 109
TABLE 7.5. Characterization of the principle on the fan, San Luis Valley,
Colorado.
Gunbarrel loamy sand 0—48 inches course loamy sand
48-60 inches sand to sand and gravel
0-48"
48-60"
Per-
Percent Passing Sieve Size pH meability
No. 4 No. 10 No. 200 (in./hr)
90-100 90-100 15-30 7.9-9.0 2.5-5.0
75-90 65-80 5-15 7.9-9.0 >5.
Water-
holding
Capacity
(in. /in.)
0.05
0.05
Depth to sand and gravel 24-60 inches
Water table range 1-5 feet
Sand 83-92% pH
Silt 4-11% Salinity millimhos/cm 1.3-1.8
Clay 4-7 % Organic matter 0.4 or less
CaCO3 equivalent percent 0.7-2.3
Moisture at saturation 19-20
Cation exchange capacity 5.0-8.3
Source: R. K. Glanzman and J. M. Klein. (Data to be published.) Private
communication.
as soil permeability, soil porosity, temperature, rainfall, snow melt,
or volumes of irrigation water, it is obvious that nitrate concentration
in a water supply will vary according to the season of the year and
the amount of water flow at any given time.
ANIMAL SOURCES OF NITROGEN
Numbers of livestock vary throughout the United States as
follows: 74% of the hogs, 42% of the cattle, and 39% of the poultry
are contained in the north-central region (Loehr, 1969); the south-
central and western regions contain 41% of the cattle; and the
poultry population is evenly divided throughout the country. Dra-
matic increases in numbers of cattle have been noted in the United
States. For example, an increase of 36 million head has occurred
during the past 25 years, and 17 million of this increase occurred
during the last 8 years. The poultry industry today is a $3.4 billion
industry. Cattle feedlots have expanded rapidly also in the last few
years. Livestock on American farms produce about 1,814 teragrams
of manure each year. In units of population equivalents, the nitrogen
contribution of domestic wastes is estimated to be 3.6 to 5.4 kg per
year, or 0.015 kg per capita per day. For chickens, the nitrogen con-
tribution per animal per day is 0.001; for swine, 0.02; for dairy cattle,
0.18; and for beef cattle, 0.14. Swine, dairy cattle, and beef cattle
on a population-equivalent basis produce more nitrogen per capita
per day than that derived from domestic sewage wastes. The pro-
duction of animal wastes in the United States exceeds the waste
produced by the human population by about 5 to 1 on a BOD (bio-
logical oxygen demand) basis, 10 to 1 on a total-dry-solids basis, or
7 to 1 on a total-nitrogen basis (Table 7.6).
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110 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
VA/ELt_.
106'iS1
FIG. 7.2. Concentration of nitrate, Rio Grande Fan, San Luis Valley,
Colorado.
Nitrates in Wells
Analysis of 6,000 rural water supplies (Keller and Smith, 1967;
Smith, 1967) indicated that the sources of nitrogen were animal
wastes, improperly constructed shallow wells, and septic-tank drain-
age. There was some evidence of nitrogen infiltration from heavy
annual applications of nitrogen fertilizer. The soil was an alluvial
sand. Clay soils generally do not transmit nitrogen. In this study,
livestock were considered a more important source of contamination
than nitrogen fertilizer. None of the reservoirs sampled showed
increases in nitrate due to fertilization. It was thought that nitrate
infiltration is relatively slow. The infiltration mechanism involves
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Chapter 7 / SOURCES OF NITROGEN IN WATER /111
TABLE 7.6. Average animal waste characteristics.
Kilograms per Animal per Day Per Capita Equivalent*!
Specie
(1)
Chickens
Swine
Dairy Cattle . .
Beef Cattle ....
BOD,
(2)
0.0068
0 136
0.45
0.45
Total
dry
solids
(3)
0 027
041
4.54
4.54
Total*
nitrogen
(4)
0 001
0 023
0.18
0.14
BOD,
(5)
0 11
1 7
8.0
6.0
Total
dry
solids
(6)
0 09
1 7
18.0
18.0
Total
nitrogen
(7)
0 11
1 5
12.0
9.0
Source: Loehr (1969). Reprinted with permission from R. C. Loehr.
* Based on average characteristics in municipal sewage: 0.077 kg BOD;
per capita per day; 0.25 kg total solids per capita per day; and 0.015 kg
total nitrogen per capita per day.
"i" Number of people equivalent to one animal.
4. Total Kjeldahl nitrogen.
trapping soil fissures during drought and further infiltration washed
during times of heavy rains. Indeed, without microorganism pop-
ulations to reduce nitrates to ammonia, the nitrates persist.
Nitrogen from sinkholes and cave leaching is a source of ni-
trate in wells. It was estimated that as many as 1,450 known caves
in Missouri contain bat guano. In Cooper County, Missouri, nearly
50% of drilled wells, over 85% of dug wells, and 80% of springs
contained more than 5 mg/1 nitrogen. Keller and Smith (1967)
attribute this to the following sources: fertilizers, feedlots, bat guano,
and biological waste materials.
Waterfowl as a Source of Nitrogen
Duck wastes are quoted as being as high as 0.95 kg of fixed
nitrogen per duck per year. Estimating 100 million waterfowl in the
United States, they would produce 91 to 227 million kilograms of
nitrogen per year. Wild duck nutrient contributions to 1,416-hectare
Lake Chautauqua in Illinois were 14.3 kg of total nitrogen per hectare
of water (Paloumpis and Starrett, 1960).
Feediots as a Source of Nitrogen
Many workers have shown that feedlot runoff pollutes streams;
such runoff has high ammonia concentrations and reduces the oxygen
content. At 4.41 cm of rain per hour, nitrogen concentrations in
the form of ammonia can run as high as 400 mg/1 within an hour
after the rain starts. Water which has moved through feedlots
commonly contains nitrates and ammonium compounds, and has
an offensive odor. The animal wastes in feedlots and in other areas
of containment can, under the proper conditions, act as sources of
-------
112 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
nitrogen in both surface waters and groundwaters. Typical examples
are given below.
It has been confirmed that groundwater under feedlots is usu-
ally contaminated by nitrate (Stewart et al., 1967, 1968). It has also
been shown, however, that nitrate levels in the range of 10 to 30
mg/1 are found in groundwater beneath irrigated fields.
Atmospheric ammonia measured near feedlots (Hutchinson and
Viets, 1969) was as much as 20 times greater than near control sites.
The conclusion was that surface waters in the immediate vicinity of
a feedlot can become enriched in nitrogen by absorption of atmos-
pheric ammonia volatilized from the feedlot. These data seem to
indicate that not only are runoff and percolation sources of nitrogen
from feedlots, but atmospheric pollution is a serious consideration
as well.
Data from the above study show that at a sampling station 0.4
km west of a 90,000 unit feedlot, 2.8 kg/ha of ammonia were ab-
sorbed each week, which would be 146 kg/ha on an annual basis.
In other sites where no feedlots were located, the weekly ammonia
nitrogen absorption was 0.15 kg/ha.
Hanway et al. (1963) found evidence for the fact that nitrates
are more concentrated below or near the area of a waste accumula-
tion or disposal, such as manure piles, feedlots, septic tanks, disposal
fields, cesspools, and privies, than in other areas of a fertilized field.
Nitrate also may be marshalled in water under low areas and water-
ways that convey runoff from higher ground. Water which percolates
through feedlots, decomposing peat soils, heavily mineralized soils,
or other nitrogen sources moves nitrates to the groundwater.
Stewart et al. (1968) found that nitrate concentrations in soil
under feedlots ranged from none to more than 5,604 kg/ha in a 6.1-
meter profile. They found that even though the ratio of irrigated
lands to feedlots was 200:1, calculations based on the average con-
tent of the irrigated fields, excluding alfalfa, and the rate of water
moving through these profiles suggested that 28 to 34 kg of nitrogen
per hectare were lost annually to the water table. This indicated
that feedlots contribute very large amounts of nitrate to the soil pro-
file with respect to irrigated land. An important observation is that
feedlots are usually located near homesteads and thus have a pro-
nounced effect on rural water supplies.
The amount of nitrate found under cultivated dry land was
significant in relation to historic loss of total nitrogen during cultiva-
tion. Studies have shown that total nitrogen in dry-land soils de-
creases about 50% during 30 to 50 years of cultivation. A large
part of this decrease cannot be accounted for by crop removal.
Lotspeich et al. (1969) pointed out the negligible loss of nitrogen in
the Great Plains because of low rainfall. Losses by volatilization and
erosion were emphasized but also seemed to be minimal.
Collected data suggest that leaching losses may have been
greatly underestimated. There is an accumulation of nitrate in the
2.4- to 3.0-meter depth just below the rooting depth of most dry-land
crops. The rainfall in the study area averaged about 38 cm per year.
Stewart et al. (1968) list the chemical data for water samples
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 113
_ x
FIG. 7.3. Feedlot sources of nitrogen and groundwater. (Engberg,
1967.)
taken from beneath feedlots and adjacent irrigated fields. The
average concentration of ammonium nitrate of the waters beneath
28 irrigated fields was 0.2 mg/1. On the other hand, water from
beneath 29 feedlots averaged 4.5 mg/1 ammonium nitrogen. It
was also observed that samples high in organic carbon contained
high amounts of ammonium nitrogen. Nitrite was usually high un-
der feedlots. These results indicate the kinds and amounts of ma-
terials moving through soil to groundwater.
The importance of well location with respect to feedlots was
demonstrated by Engberg (1967). In a study in Holt County, Ne-
braska, high nitrate concentrations were observed in domestic wells.
In Figure 7.3A, an example is given of undisturbed lateral move-
ment of high nitrate water in the direction of groundwater move-
ment. Figures 7.3B and 7.3C illustrate well pumping that induces
movement of high nitrate water into wells. Figure 7.3D illustrates
a properly located well that will be free of nitrate. (Also see Fig. 7.4.)
The aforementioned studies make it apparent that livestock-
feeding operations are becoming more concentrated and that their
effect on groundwater and surface water is indeed noticeable as a
source of nitrogen.
RURAL WASTE
Barnyard Wastes
The California State Water Pollution Control Board (1953) re-
ports 1,300 mg/1 of ammonia and organic nitrogen in percolate
from refuse.
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114 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
D
FIG. 7.4. Wells A and B yield low nitrate water, C and D yield high
nitrate water. (Engberg, 1967.)
Feeds
Nitrates are likely to be found in feeds including forages, hay,
weeds, fodder, silages, or pasture grasses grown on soils that have
received heavy applications of manure or nitrogen fertilizers (Han-
way et al., 1963). This is especially true when drought, shade, dis-
ease, herbicide applications, or other interfering factors affect normal
growth and development of the plant. Nitrate concentrations are
highest in immature plants. Stems of plants concentrate the majority
of nitrate; intermediate levels are found in the leaves, and low7 levels
in the grain.
URBAN WASTE
Domestic Wastewater
Domestic wastewater effluents range in concentrations from 18 to
28 mg/1 of nitrogen (exclusive of molecular nitrogen) without spe-
cific treatment for nitrogen removal, according to the Task Group
2610 Report (1967).
Ammonia nitrogen is the predominant form of nitrogen in efflu-
ents from primary and high-rate treatment plants.
Although it is not normal to add sewage to a water supply, it
is possible that by filtration and proper sewage treatment, waters
that once contained sewage could safely be added to a water supply.
The concentration of nitrogen in a settled domestic sewage is approxi-
mately 80 to 120 mg/1.
The urban runoff which accumulated from three streams in an
area containing large reservoirs, roads, and some logging, but no
human habitation, is shown in Table 7.7 (Sylvester, 1961). The
-------
TABLE 7.7.
Chapter 7 / SOURCES OF NITROGEN IN WATER / 115
Mean nutrienf concentrations from runoff sources in parts per
billion.
Urban street drainage
Urban street drainage (median) .
Streams from forested areas ...
Subsurface irrigation drains
Surface irrigation drains
Green Lake
Total
Phos-
phorus
(P)
. 208
. . 154
69
. . 216
. . 251
76
Soluble
Phos-
phorus
(P)
76
22
7
184
162
16
Nitrates
(N)
527
420
130
2,690
1,250
84
Total
Kjeldahl
Nitrogen
(N)
2,010
410
74
172
205
340
Source: Sylvester (1961).
sources were the Yakima River irrigation return flow drains and the
Green Lake in Washington near Seattle. Nitrate nitrogen levels were
generally above 200 /*g/l. The mean nutrient concentration was
about 800 /ig/1.
The average per-capita refuse originating from food and other
materials imported into the Lake Tahoe watershed is 0.9 kg per day
of which 1% is nitrogen (McGauhey et al., 1963).
Nitrogen compounds used for crop fertilization and disposal
of sewage and industrial wastes were pinpointed as sources of
groundwater nitrate (Navone et al., 1963).
Groundwater Infiltration
Nitrate movement downward in a silt loam is relatively small
(Herron et al., 1968) and corroborates the fact that there is a lack
of downward movement of nitrogen from the surface.
Fifty wells were examined in a 31-square-kilometer area (Behnke
and Haskell, 1968) in the northeastern section of Fresno, California.
Most of the wells were unperforated, open-bottomed casings 27 to 43
meters long. Behnke and Haskell identified areas of increased nitrate
concentrations on a contour map and drew a nitrate concentration
map of the area. The background nitrate concentration was 11 to 15
mg/1. In a zone directly under the Clovis sewage treatment plant,
a concentration of 35 mg/1 nitrate was found. A second area of
25 mg/1 concentration extended in a zone in a southwesterly direc-
tion and coincided with the strike of the flow line in the same vicinity
as determined by a water-table contour map. A third zone of nitrogen
underlies a subdivision containing individual septic tanks. The
nitrate concentration again ranged from 35 to 25 mg/1. It was
noted that nitrate concentrations decreased from 50 to 25 mg/1 in a
lateral distance of eight-tenths of a kilometer. This study also found
the nitrate concentrations in the top 3 meters of the groundwater
body was one-third greater than in the rest of the water column.
-------
116 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Leaching and Erosion
A study conducted in California (Stout and Bureau, 1967)
showed that a major part of the nitrate reaching underground
aquifers was from urban areas and sewage fields. In addition, it
was found that agricultural crops reduce the amount of nitrate in
irrigation water that returns to lower soil depths.
In Missouri, where the precipitation normally exceeds evapo-
transpiration, soils are acid on the surface. Salts that weather from
soil minerals are regularly leached and are a normal constituent of
drainage water. Hence, elements from the land that can pollute
streams are derived more from erosion sediments than from leach-
ates. The main sources of sediment that enter water courses are soil
eroded from urban developments, from highway construction areas,
and from agricultural land. Losses of essential mineral nutrients
during the past half century in the United States have been greater
from erosion than from crop removal. On soils that have low ex-
change capacities, leaching of nitrate can be serious.
Storm Water
Storm-water runoff, because of storm overflows, can supply
some nitrogen to rivers. For example, analysis of River Erwell at
Ratcliffe showed that ammoniacal nitrogen was in the order of 4.9
mg/1 and albuminoid nitrogen in the order of 32.6 mg/1 (Klein et
al., 1962).
Storm runoff measured over a year's period from an 11-hectare
residential, commercial, urban area indicated that phosphorus (as
phosphate) and total nitrogen are 9 and 11%, respectively, of the
estimated raw sewage content from sources in the area. At Co-
shocton, Ohio, two storms with 5.61 and 12.93 cm of rainfall per
storm produced runoff of 61.7 to 714 kiloliters per hectare. Phosphate
in the runoff water ranged from 0.06 to 0.47 kg/ha and total
nitrogen ranged from 0.22 to 6.86 kg/ha (U.S. Public Health Service,
1964).
INDUSTRIAL WASTE
Several substances containing nitrogen are commonly found in
industrial wastes. For example, ammonia is a waste material from
gas and coke manufacturing and other chemical manufacturing
processes. Cyanide is evolved during gas manufacture, plating, case
hardening, and metal cleaning. Nitrogen compounds also originate
from explosive factories and other chemical works.
In November 1966 a severe ammonia infestation reached the
Becva River in Czechoslovakia. The pollution was caused by a chem-
ical plant where the equipment for the production of granulated
superphosphate was taken out of operation. Simultaneously, the
ammonia water storage tanks were cleaned. During cleaning, the
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 117
inlet to the chemical sewage systems became clogged, and the water
overflowed into the normal sewage system. This resulted in severe
contamination of the river and led to poisoning of fish along a 20-
kilometer length from the site of entrance (Dockal and Varecha,
1967).
A study conducted on Lake Norrviken in central Sweden during
the years 1961 to 1962 indicated that wastewater from a yeast
factory was responsible for more than 80% of the nitrogen and
70% of the phosphorus found in the lake. Only about 40% of the
nitrogen and 50% of the phosphorus input to the lake leaves the
lake through its outflow. The rest of the phosphorus accumulated
in the sediments, but a large fraction of the nitrogen was presumed
to undergo denitrification to free nitrogen. On the basis of the ratio
of the content of nitrogen to phosphorus in surface sediment, this
fraction was calculated to be about 37% of the total nitrogen input
to the lake or 60% of the amount which does not leave the lake
through the outflow (Ahlgren, 1967).
PRISTINE SOURCES OF NITROGEN
In areas never touched by man for purposes of building or culti-
vation, nitrate from natural deposits and normal decomposition of
organic matter is present in soil profiles and groundwaters. Nitrate
accumulates in salty areas of semiarid and arid regions where sur-
face waters evaporate. Also irrigation without adequate drainage
accelerates nitrate accumulation. These natural sources cannot be
neglected in any appraisal of a nitrate infiltration problem. Unless
such additions of nitrogen to a basin or watershed are balanced by
withdrawals or denitrification losses, soluble nitrogen will accumu-
late in surface and soil profiles.
In many cases, natural sources of nitrogen are sufficient to cause
large nitrogen inputs into an area. A good example of this situation
was reported by Frink (1967) wherein the nutrient input from a
largely forested watershed with no overt source of pollution was
found to be adequate to support abundant vegetative growth. In
addition, a reservoir was noted in which the upper centimeter of
the bottom sediment of a lake contained at least 10 times the esti-
mated annual input of nitrogen and phosphorus to the lake. A nitro-
gen budget of this lake indicated that in kilograms of nitrogen per
lake, the annual input from the watershed was 30,700; the output
from the lake was 27,500, resulting in a mean net input of 3,200
kg/yr for the lake.
POND WATER
Ponded water also received nitrate from the sources mentioned
above. Ponded water that contains abundant algal or other growth,
however, has less nitrate than water which does not contain this
growth. Apparently the plant growth uses excess nitrate about as
-------
118 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
rapidly as the nitrate enters the pond. Ponded water also loses ni-
trate by denitrification and anaerobic decomposition of organic
matter in the ponded water. This nitrate may eventually escape as
molecular nitrogen.
Autotrophic organisms, particularly those of green algae,
metabolically produce hydroxylamine in highly eutrophicated water
(Koprivik and Burian, 1966). This biological origin of hydroxylamine
is confirmed by the fact that higher concentrations were observed
at night than during the day. The occurrence of hydroxylamine in
pond water is influenced by its relation to the oxygen content. The
authors find great differences between origin and existence of this
chemical in water.
Infiltration from Ponds
Passage of water through the ground by infiltration from ponds
has little or no effect on nutrient concentrations in the Tahoe Basin
near Lake Tahoe, Nevada (McGauhey et al., 1963), and subsequent
flow through the ground affects only partial removal of nutrients.
Nitrate appears to be transported by groundwater without significant
reduction by earth materials. Percolation of water through the
ground dees materially reduce the concentrations of other chemical
constituents. Wisconsin stabilization ponds indicate annual per-
capita contributions of 1.9 kg of inorganic nitrogen. Nine Springs
sewage treatment plant, serving a 135,000 population with primary
and secondary filtration, had an annual per-capita contribution of
3.9 kg inorganic nitrogen. In contrast, surface runoff in one in-
stance was found to contain 43 kg/ha of inorganic nitrogen on a
20% slope and 20 kg/ha on an 8% slope (Eck et al.. 1957). The
annual contribution of inorganic nitrogen per hectare of drainage
area loading Lake Monona was 4.9 kg, Lake Waubesa 5.5 kg, and
Lake Kegonsa 7.2 kg (Sawyer et al., 1945). (See Table 7.8.)
MAN-MADE NITROGEN SOURCES
Deforestation
Nitrate concentration in stream water from an experimentally
deforested watershed (Likens et al., 1969) increased from 0.9 mg/1
before removal of the vegetation to 53 mg/1 two years later. The
nitrate mobilization was attributed to increased microbial nitrifica-
tion and was equivalent to all the other net cationic increases and
anionic decreases observed in the drainage water of the Hubbard
Brook Experimental Forest in central New Hampshire.
Dredging
Enlargement of the Chesapeake and Delaware Canal and its
approaches required that large volumes of bottom material be re-
-------
TABLE 7.8 Distribution of nitrogen in ponds.
Org.-N (mK/1) .
NIL-N (ms/1) •
NO.-.-N (mg/1) .
Al^uc (no. /ml)
Haw
Sewage
. . 26.3
. . 32.4
. . 0.0
. . Nil
\
12.5
40.4
0.0
7 X 10 :
2
14.5
52.5
0.0
7.1 X 10':
3
11.2
48.7
0.3
2.4 x 107
Ponds
4
13.7
45.0
0.5
1.4 x 10;
5
16.4
42.5
0.2
1.2 X 10"
6
8.9
40.0
0.5
7.2 /. 10:
7
8.1
28.1
0.2
2.9 x 10
8
7.5
18.9
0.8
8.5 / 10
Source: Parker (1962).
-------
120 / PART 2 I PLANT NUTRIENTS AS WATER POLLUTANTS
moved from channel areas and relocated. In the Chesapeake ap-
proach area, about 7.4 x 10° cubic meters of silt and clay were
scheduled to be dredged. As a result of data gathered and projected
by Biggs, it was concluded that such action would increase the total
phosphate and nitrogen by a factor of 50 or 100 over ambient levels
in the immediate vicinity of the proposed disposal plant (Biggs,
1968).
SUMMARY AND CONCLUSIONS
It has been shown that there are multiple sources of nitrogen
to water supplies. These include atmospheric, geologic, biogenic,
rural runoff, urban runoff, sewage, irrigation, return flow, animals,
sinkholes, caves, feedlots, pollen, rural waste, industrial waste, pond
waters, deforestation, and land stripping, among others.
Generally, salts of nitrogen applied as fertilizer do not move
either vertically or laterally to any significant extent. Movement is
a function of soil type, soil saturation, applied water volume, and
temperature. A few examples of such movement to groundwater
and surface-water supplies and the relative significance of such
movement were discussed.
Nitrate in a nonsalt form seems to have higher soil infiltration
capacity than salt nitrogen. This is dependent, however, upon the
physical conditions of the soil and the hydrology of the region.
Other sources not directly used as nutrients to plants, such as
soil erosion, urban and industrial wastes, natural soil nitrogen loss,
land renovation, deforestation, and atmospheric fallout, were eval-
uated with respect to their importance as a source of nitrogen in
water. In general, industrial waste, rural runoff (including agri-
cultural land and nonagricultural land runoff), farm animal waste,
and domestic waste are the dominant sources in surface waters.
In groundwater supplies, specifically wells, the usual sources
of nitrogen are feedlots, privies, septic tanks, or other waste forms.
A few examples were given of geologic sources within the aquifer
either as nitrate deposits or nitrate minerals.
Dissemination of nitrogen from a plant-nutrient source is de-
pendent upon the geology and hydrology extant at the nitrogen
origin. With sufficient data describing these variables it should be
possible to characterize the potential for retention or loss of nitrogen
from the point of origin and the possibility of entrance into a surface
or groundwater supply. Certainly, with the varied sources of nitrogen
now available, and the increasing amount of man-made nitrogen
materials added to the environment each year, a careful check is
necessary on the amounts and sources of nitrogen entering water
supplies.
REFERENCES
Ahlgren, I. 1967. Limnological studies of Lake Norrviken, a eutroph-
icated Swedish lake. Schweiz. Z. Hydrol. 29:54-90.
Behnke, J. J., and Haskell, E. E., Jr. 1968. Ground water nitrate
-------
Chapter 7 / SOURCES OF NITROGEN IN WATER / 121
distributions beneath Fresno, California. /. Am. Water Works
Assoc. 60(4): 477-80.
Biggs, R. B. 1968. Environmental effects of overboard spoil disposal.
J. Sanit. Eng. Div. Am. Soc. Civil Engrs. 94 (SA-3): 477-87.
Brown, M. A., and Volk, G. M. 1966. Evaluation of ureaform fertil-
izer using nitrogen-15 labeled materials in sandy soils. SoiZ Sci.
Soc. Am. Proc. 30 (2): 278-81.
Calif. State Dept. of Public Health, Bur. of Sanit. Eng. 1963. Occur-
rence of nitrate in ground water supplies in southern California.
Calif. State Water Pollution Control Board. 1953. Field investiga-
tion of waste water reclamation in relation to ground water
pollution. Calif. State Water Pollution Control Board Publ. 6.
Carter, D. L., Bobbins, C. W., and Bondurant, J. A. 1969. The effects
of irrigation on water quality and pollution in south central
Idaho. In Western Soc. Sot7 Sci., 1969 Meetings, Wash. State
Univ., Pullman.
Comly, H. H. 1945. Cyanosis in infants caused by nitrates in well
waters. /. Am. Med. Assoc. 129:112-16.
Dockal, P., and Varecha, A. 1967. Destructive pollution of the Becva
River by ammonia. Vodni Hospodarstvi 17 (9): 388-91.
Domogalla, B. P., Juday, C., and Peterson, W. H. 1925. The forms
of nitrogen found in certain lake waters. /. Biol. Chem. 63:
269-85.
Doneen, L. D. 1968. Effects of soil salinity and nitrates on tile
drainage in San Joaquin Valley, California. Water Sci. and Eng.
Paper 4002. Sacramento, Calif. (1966) and San Joaquin Master
Drain, Appendix Part C. Fed. Water Pollution Control Admin.,
Southwest Region.
Dugdale, V. A., and Dugdale, R. C. 1965. Nitrogen metabolism in
lakes. III. Tracer studies of the assimilation of inorganic nitro-
gen sources. Limnol. Oceanog. 10(1): 53-57.
Eck, P., Jackson, M. L., Hayes, O. E., and Bay, C. E. 1957. Runoff
analysis as a measure of erosion losses and potential discharge
of minerals and organic matter into lakes and streams. Sum-
mary Rept. Lakes Investigation, Univ. of Wis.
Ehrlich, G. G., and Slack, K. V. 1969. Uptake and assimilation of
nitrogen in microecological systems. Am. Soc. Testing Materials.
Spec. Tech. Publ. 448, pp. 11-23.
Engberg, R. A. 1967. The nitrate hazard in ivell water. Nebr. Water
Survey Paper 21. Univ. of Nebr. Conserv. and Survey Div.
Lincoln.
Feth, J. H. 1966. Nitrogen compounds in water-A review. Water
Resources Res. 2(1): 41-58.
. 1967. Chemical characteristics of bulk precipitation in the
Mojave Desert Region, California. U.S. Geol. Survey Prof. Paper
575-C, pp. 222-27.
Frink, C. R. 1967. Nutrient budget: rational analysis of eutrophi-
cation in a Connecticut lake. Environ. Sci. Tech. 1 (5): 425—28.
Grill, E. V., and Richards, F. A. 1964. Nutrient regeneration from
phytoplankton decomposing in sea water. /. Marine Res. 22 (1):
51-69.
Hanway, J. J., Herrick, J. B., WiUrich, T. L., Bennett, P. C., and
McCall, J. T. 1963. The nitrate problem. Agronomy 615:1.
. The nitrate problem. Iowa State Univ. of Sci. and Tech. Spec.
Rept. 34.
Herron, G. M., Terman, G. L., Drier, A. F., and Olsen, R. A. 1968.
-------
122 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Residual nitrate nitrogen in fertilized deep loess-derived soils.
Agron. J. 60:477-82.
Hutchinson, G. E. 1954. The biogeochemistry of the terrestrial at-
mosphere. In The earth as a planet, ed. G. P. Kuiper, pp. 371—
433. Chicago: Univ. of Chicago Press.
Hutchinson, G. L., and Viets, F. G., Jr. 1969. Nitrogen enrichment
of surface water by absorption of ammonia volatilized from
cattle feedlots. Science 166 (3904): 514-15.
Inglish, H. J. 1967. Nitrates in private water supplies in Morgan
County, Missouri. Milk Food Technol. 30 (7): 224-25.
Johnston, W. R., Ittihadieh, F., Daum, R. M., and Pillsbury, A. F.
1969. Proc. SoilSci. Soc., p. 287.
Junge, C. E. 1958. The distribution of ammonia and nitrate in
rainwater over the United States. Trans. Am. Geophys. Union
39(2): 21-248.
Keller, W. D., and Smith, George E. 1967. Ground water contami-
nation by dissolved nitrate. Geol. Soc. Am. Spec. Papers 90:48-
59.
Klein, L., Jones, J. R. E., Hawkes, H. A., and Downing, A. L. 1962.
River pollution. II. Causes and effects. London: Butterworth.
Koprivik, B., and Burian, V. 1966. Origination and occurrence of
hydroxylamine in pond water. Cesk. Hygiena 11 (5): 268—75.
Koyama, T., and Tomino, T. 1967. Decomposition process of organic
carbon and nitrogen in lake water. Geochem. ]. 1 (3): 109—24.
Krause, H. H., and Batsch, W. 1968. Movement of fall-applied nitro-
gen in sandy soil. Can. J. Soil Sci. 48:363-65.
Likens, G. E., Bormann, F. H., and Johnson, N. M. 1969. Nitrifica-
tion: importance to nutrient losses from a cutover forested
ecosystem. Science 163 (3872): 1205-6.
Loehr, R. C. 1969. Animal wastes, a national problem. /. Sanit. Eng.
Div. Am. Soc. Civil Engrs., 95 (SA-2): 189-220.
Lotspeich, F. B., Hauser, V. L., and Lehman, O. R. 1969. Quality
of water from play as on the southern High Plains. Water Re-
sources Res. 5 (1): 48-57.
McGauhey, P. H., Eliassen, R., Rohlich, G., Ludwig, H. F., and Pear-
son, E. A. 1963. Comprehensive study on protection of water
resources of Lake Tahoe Basin through controlled waste dis-
posal. Prepared for the Board of Directors, Lake Tahoe Area
Council, Al Tahoe, Calif.
McGuinness, J. L., Harrold, L. L., and Dreibelbis, F. R. 1960. Some
effects of land use and treatment on small single crop water-
sheds. /. Soil Water Conserv. 15 (2): 65-69.
Macrae, I. C., Rosabel, R. A., and Salandan, S. 1968. The fate of
nitrate nitrogen in some tropical soils following submergence.
SoilSci. 105(5): 327-34.
Matheson, D. H. 1951. Inorganic nitrogen in precipitation and at-
mospheric sediments. Can. J. Technol. 29:406-12.
Metzler, D. F., and Stoltenberg, H. A. 1950. The public health sig-
nificance of high nitrate waters as a cause of infant cyanosis
and methods of control. Trans. Kansas Acad. Sci. 53:194-211.
Meyer, J., and Pampfer, E. 1959. Nitrogen content of rainwater col-
lected in the humid central Congo Basin. Nature 184:717.
Miller. R. B. 1961. The chemical composition of rainwater at Taita,
New Zealand, 1956-1958. Nezv Zealand J. Sci. 4:844.
Mink, J. F. 1962. Excessive irrigation in the soils and ground water
of Oahu, Hawaii. Science 135 (3504): 672-73.
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Chapter 7 / SOURCES OF NITROGEN IN WATER / 123
Moe, P. G., Mannering, J. V., and Johnson, C. B. 1967. The loss of
fertilizer nitrogen in surface runoff water. Soil Sci. 104 (6): 389—
94.
. 1968. A comparison of nitrogen losses from urea and am-
monium nitrate in surface runoff water. Soil Sci. 105 (6): 428—
33.
Navone, R., Harmon, J. A., and Voyles, C. F. 1963. Nitrogen content
of ground water in southern California. /. Am. Water Works
Assoc. 55 (5): 615-18.
Olsen, R. J., Hensler, R. F., Attoe, O. J., Witzel, S. A. 1969. Effect of
fertilizer nitrogen, crop rotation and other factors on amounts
and movement of nitrate nitrogen through soil profiles. Agron.
Abstr. Am. Soc. Agron., 61st Annual Meeting, p. 104.
Overrein, L. N. 1968. Lysimeter studies on tracer nitrogen in forest
soil. I. Nitrogen losses by leaching and volatilization after addi-
tion of urea-N15. Soil Sci. 106 (4): 280-90.
Owens, M., and Wood, G. 1968. Some aspects of the eutrophication
of water. Water Res. 2:151-59.
Paloumpis, A. A., and Starrett, W. C. 1960. An ecological study of
benthic organisms in the three Illinois river flood plain lakes.
Am. Midland Naturalist 64(2): 406-35.
Parker, C. D. 1962. Microbiological aspects of lagoon treatment. J.
Water Pollution Control Federation 34:149-61.
Peterson, H. B., Bishop, A. A., Law, J. P., Jr. 1969. Problems of
pollution of irrigation waters in arid regions. In AAAS inter-
national conference on arid lands in a changing world (preprint).
Pratt, P. F., Cannell, G. H., Garber, M. J., and Blair, F. L. 1967.
Effect of three nitrogen fertilizers on gains, losses, and distribu-
tion of various elements in irrigated lysimeters. Hilgardia
38 (8): 277.
Preul, H. C., and Schroepfer, G. J. 1968. Travel of nitrogen in soils.
/. Water Pollution Control Federation 40 (1): 30-48.
Putnam, H. D., and Olsen, T. A. 1959. A preliminary investigation of
nutrients in western Lake Superior, 1958-1959. School of Pub-
lic Health, Univ. of Minn.
. 1960. An investigation of nutrients in ivestern Lake Superior.
School of Public Health, Univ. of Minn.
Sawyer, C. N., Lackey, J. B., and Lenz, R. T. 1945. An investigation
of the odor nuisances occurring in the Madison lakes, par-
ticularly Monona, Waubesa and Kegonsa from July 1942 to
1944. Report of Governors Committee. Madison, Wis. 2 vol-
umes.
Sinha, H., and Prasad, K. 1967. Performance, transformation and
movment of urea in acid soils. J. Indian Soc. Soil Sci. 15(4):
281-87.
Smith, G. E. 1967. Fertilizer nutrients as contaminants in water
supplies. In Agriculture and the quality of our environment.
Publ. 85, pp. 173-86. Am. Assoc. for the Advancement of Sci.
Stewart, B. A., Viets, F. G., Jr., Hutchinson, G. L., Kemper, W. D.,
Clark, F. E., Fairbourn, M. L., and Strauch, F. 1967. Distribution
of nitrates and other water pollutants under fields and corrals in
middle South Platte Valley of Colorado. USDA, ARS 41-134.
Stewart, B. A., Viets, F. G., Jr., and Hutchinson, G. L. 1968. Agricul-
ture's effect on nitrate pollution of ground water. /. Soil Water
Conserv. 23 (1): 13-15.
Stout, P. R., and Burau, R. G. 1967. The extent and significance of
-------
124 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
fertilizer build-up in soils as revealed by vertical distribution of
nitrogenous matter between soils and underlying water reser-
voirs. In Agriculture and quality of our environment. Publ. 85,
pp. 283—310. Am. Assoc. for the Advancement of Sci.
Sylvester, R. O. 1961. Nutrient content of drainage water from for-
ested, urban and agricultural areas. Algae and Metropolitan
Wastes. U.S. Public'Health Serv. SEC TR W61-3, pp. 80-87.
Sylvester, R. O., and Seabloom, R. W. 1963. Quality and significance
of irrigation return flow. /. Irrigation Drainage Div. Am. Soc.
Civil Engrs. 89 (IR-3). Proceedings Paper 3624, pp. 1-27.
Task Group 2610-P Report. 1966. Nutrient-associated problems in
water quality and treatment. /. Am. Water Works Assoc.
58 (10): 1337-55.
Task Group 2610-P Report. 1967. Sources of nitrogen and phos-
phorus in water supplies. J. Am. Water Works Assoc. 59:344—
66.
Timmons, D. R., Burwell, R. E., and Holt, R. F. 1968. Loss of crop
nutrients through runoff. Minnesota Sci. 24 (4): 1.
U.S. Geological Survey, Water Resources Division. 1965. Conference
on Nitrogen Chemistry, 1965. Menlo Park, Calif., Sept. 21-22.
U.S. Public Health Service. 1964. Basic and Applied Sciences Branch,
Division of Water Supply and Pollution Control. Activities Re-
port July 1, 1963-June 30, 1964.
Weidner, R. B., Christiansen, A. G., Weibel, S. R., and Robeck, G. G.
1969. Rural runoff as a factor in stream pollution. /. Water
Pollution Control Federation 41 (3): 377-84.
White, A. W., Burnett, A. P., Jackson, W. A., and Kilmer, V. J. 1967.
Nitrogen fertilizer loss in runoff from crop land tested. Crops
Soils 19 (4): 28.
Whitehead, E. L, and Moxon, A. L. 1952. Nitrate poisoning. S. Dak.
State College Bull. 424.
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CHAPTER EIGHT.
CHEMISTRY OF NITROGEN IN SOILS
F. J. STEVENSON and G. H. WAGNER
I HE importance of N from the standpoint of soil fertility has
long been recognized, and our knowledge concerning the nature,
distribution, and transformations of N compounds in soil is exten-
sive. Early work dealt largely with practical aspects of maintaining
a reserve of humus N for plant growth; more recently, interest has
been centered on the efficient use of fertilizer N. Increasing attention
is now being given to problems associated with the disposal of nitrog-
enous wastes on farmland and of the fate of applied N as related
to water quality.
A schematic diagram depicting the cycle of N in soil is given
in Figure 8.1. Ammonium (NH4+) added as fertilizer, or formed
from decay of plant and animal residues, is temporarily held by
the exchange complex of the soil but is eventually oxidized to nitrate
(NO3-) unless it becomes fixed by humus or clay minerals. Immo-
bilization by microorganisms leads to conversion of NH4+ and NO3~
to the humus form. The NO3~ is subject to leaching, and it can be
converted to gaseous products through a process called denitrification.
Losses of N can also occur through chemical reactions involving ni-
trite (NO.,-).
The above considerations emphasize that a close relationship
exists between inorganic and organic forms of N, and that the sub-
ject of soil N deals not only with the nature and distribution of vari-
ous inorganic and organic compounds but of their interactions with
each other and with mineral matter. An understanding of the chem-
istry of soil N complexes, and of the reactions they undergo, is of
considerable importance from the standpoint of evaluating agricul-
tural practices as they relate to the occurrence of NO,- and nitrog-
enous organic substances in natural waters.
The purpose of this chapter is to summarize our knowledge of
the kinds and amounts of N compounds in soil. Brief mention will
be made of chemical transformations involving NH4" and NO2~.
The subject of biological transformations will be mentioned only as
F. J. STEVENSON is Professor of Soil Chemistry, Department of Agron-
omy, University of Illinois. G. H. WAGNER is Associate Professor,
Department of Agronomy, University of Missouri.
725
-------
126 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
REMOVED FROM CYCLE
BY HARVESTING
/
1
S, *
f
.Xl\ON —
/•$-*
fc-..
*
^JSOIL ORGAHICI mutML
1^1 MATTER fnATTtn
1
AMI. ONIFieATION CHt-IC4L
1 ^HEACTIOM
METALLO -ORGAN 1C
AND
ORGANO-CLAY
COMPLEXES
/t»CH*»«CA«LE\
FIG. 8.1. The N cycle in soil. (From Stevenson, 1965.)
far as it contributes to our understanding of the chemistry of soil
N.
INORGANIC FORMS OF N IN SOIL
Examination of Figure 8.1 shows that several mineral forms of
N other than NH4+ and NO3- are possible in soil. They included
nitrite (NO2-), elemental N (N2), and nitrous oxide (N2O). Nitrite
and NoO, along with nitric oxide (NO) and nitrogen dioxide (NO2),
can be found in soil only under very special circumstances (see sec-
tions dealing with denitrification and nitrite reactions). Other in-
organic N compounds, such as hydroxylamine (NH2OH) and hypo-
nitrous acid (HON = NOH), may occur as intermediates in biological
transformations of N but for the most part they are unstable and
have only a transitory existence. Elemental N is a common con-
stituent of soil air; unfortunately, it cannot be used directly by
plants.
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CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 127
Although plants are capable of utilizing organic N compounds
(for example, amino acids), practically all of the N taken up from
the soil exists in inorganic forms (as NH,+ and NO:; ).
Exchangeable NH4h and NO:f
Several recent reviews (Bremner, 1965; Harmsen and Kolen-
brander, 1965; Stevenson, 1965) have emphasized that only a small
fraction of the N in soils, generally less than 0.1%, exists in avail-
able mineral compounds (as exchangeable NH4+ and NO3~). Thus,
only a few pounds of N may be available to the plant at any one
time, even though 2 or 3 tons may be present in combined forms.
The slow conversion of nitrogenous organic substances to available
mineral forms by microorganisms has been attributed to their sta-
bilization by ligninlike substances and to the protective action of
clay minerals. The formation of stable complexes can be considered
beneficial, because the N is protected against decomposition and
subsequent leaching as NO;?-.
Levels of exchangeable NH4+ and NO:5- vary from day to day
and from one season to another, and will depend upon such factors
as climate (temperature, rainfall), organic matter content, presence
or absence of growing plants, C/N ratio of added residues, and time
and rate of application of nitrogenous fertilizers. Some important
aspects regarding available N in soils are itemized below.
1. The quantity of available N in unfertilized soil at any one time
is markedly influenced by climatic patterns (Harmsen and van
Schreven, 1955; Harmsen and Kolenbrander, 1965). For ex-
ample, in soils of the temperate humic climatic zone, the content
of inorganic N in the surface layer is lowest in winter due to
leaching, rises in spring as mineralizat'on of organic N com-
mences, decreases in summer through consumption by plants,
and increases once again in the fall when plant growth ceases
and the dead residues start to decay. The level in winter seldom
exceeds 10 ppm but may increase 4- to 6-fold or more during the
spring (Harmsen and van Schreven, 1955). The winter mini-
mum is usually ascribed to leaching.
2. Biological turnover leads to the interchange of NH4*-N and
NO3"-N with the N locked up in organic forms. Accordingly, the
amount of mineral N in. the soil at any one time represents a
balance between the opposing processes of mineralization and
immobilization, and will be determined to a large extent by the
activity of the soil microflora and the C/N ratio of decomposing
residues. A C/N ratio above a. critical value of 20 to 25 (equiva-
lent to 1.5 to 2.0% N) results in a net immobilization of N
whereas a ratio below this value leads to net miner ah" zation.
3. Growing plants have a depressing effect on the level of mineral
N in soils. The decrease when soils are cropped cannot be ac-
counted for entirely by plant uptake, and may be due to one
or more of the following: (1) inhibition of nitrification by excre-
tion products of plant roots, (2) immobilization of mineral N by
-------
128 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
lOOO
FiG. 8.2. Nitrate-N in the
upper 8 feet of 4 soil types
after the annual applica-
tion of N fertilizer for 7
years fo continuous corn in
Missouri. (Adapted from
Smith, 1968.)
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CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 129
NOs (ppm)
2OO 4OO
600
I-
CL
5-J
\ /
\ /
/**%
FIG. 8.3. Distribution of
NO.
-------
130 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
(Micrococcus denitrificans; Thiobacillus denitrificans) are also capa-
ble of converting NO3~ to N2 but they are not believed to be im-
portant in most soils.
The following pathway represents the probable mechanism of
bacterial denitrification.
+ 2H
N = N =O »N = N
Nitrous
oxide
+ 2H
- 2H.O
x, O + 4H + 4H
2HO - N ^ > 2HO - N = O > (HO _ N ~ N - OH)
^ O - 2H,O - 2H,O
Nitrate Nitrite Hyponitrite
Nitrous oxide represents an intermediate in the denitrification
process and is normally reduced further to N2; consequently, the
N20 has only a transitory existence in the soil.
Optimum conditions for denitrification are as follows:
Poor drainage: Moisture status is of importance from the stand-
point of its effect on aeration. Denitrification is negligible at
moisture levels below two-thirds of the water-holding capacity
but is appreciable in flooded soils. The process may occur in
anaerobic microenvironments of well-drained soils, such as small
pores filled with water, the rhizosphere of plant roots, and the
vicinity of decomposing plant and animal residues.
Temperature of 25° C and above: Denitrification proceeds at a pro-
gressively slower rate at temperatures below 25° C and practi-
cally ceases at 2° C.
Soil reaction near neutral: Denitrifying bacteria are sensitive to high
hydrogen ion concentrations. Their activity in acidic soils
(< pH 5) is limited.
Good supply of readily decomposable organic matter: The amount
of organic matter available to denitrifying microorganisms is
generally appreciable in the surface horizon but negligible in
the subsoil. Significant amounts of soluble organic matter may
be found under feedlots, as well as in the lower horizons of soils
amended with large quantities of organic wastes.
Denitrification can be considered a desirable process when it
occurs below the rooting zone, because of reduction in the NO3- con-
tent of groundwater. Dentrifying microorganisms are known to be
present at considerable depths in soil, and it is possible that some of
the NO3- leached into the subsoil may be volatilized before reaching
the water table. Meek et al. (1969) concluded that much of the NO3-
leached into the subsoil in irrigation waters was lost through denitri-
fication. Stewart et al. (1967) found that NO-r levels in soil under
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CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 131
feedlots decreased sharply with increasing depth and concluded that
the decrease was due to denitrification.
Under optimum conditions, NO...--N can be volatilized quanti-
tatively in a comparatively short time (24 to 36 hours). This suggests
that the denitrification process can be xitilized to eliminate excess
NO3- from soil, thereby reducing the NO3- content of percolating
water. For example, the disposal of nitrogenous wastes on farmland
results in the generation of large quantities of NO:i-, which must be
removed if groundwater contamination is to be avoided. In fine-
textured soils, reduction in NO:t- content could be accomplished by
artificially subjecting the soil to successive cycles of submergence
and drying. The anaerobic conditions created during waterlogging
would result in a significant loss of NO3- produced by oxidation of
NH4+ during the aerobic cycle. A similar procedure may prove effec-
tive in reducing the NO:!~ content of soil under feedlots.
Fixation of NH4+ by Clay Minerals
The NH4- produced in soil through microbial activity, or added
as fertilizer, can be fixed by clav minerals (Nommik, 1965\ Fixation
results from a replacement of NH4+ for interlayer cations that expand
the lattice (Ca2+, Mg2+, Na% H+), but not by those that contract the
lattice (K>, Rb\ Cs+). Soils containing large amounts of vermiculitic-
or illitic-type minerals have the capacity for fixing 1 to 6 m.e. of NH4+
per 100 g, or from about 280 to 1,680 Ib per acre plow depth. Prac-
tically no fixation will occur when the clay fraction is predominantly
kaolinitic.
The availability of NH4+ to both nitrifying microorganisms and
higher plants can be reduced by fixation. However, various studies
have shown that fixation is usually not a serious problem under nor-
mal fertilizer practices. Potassium, being a fixable cation, is effective
in blocking the release of fixed NH.,+; thus, the application of large
amounts of K+ simultaneously or immediately following an NH4+ addi-
tion may diminish the availability of the fixed NH4+ to higher plants.
Naturally Occurring Fixed NH4*
For many years, soil scientists assumed that the major inorganic
forms of N in soils were exchangeable NH4+ and N0-r. Now it is
known that soils contain fixed NH4+—that is, NH4+ held within the
lattice structures of silicate minerals. Present estimates are that 4 to
10% of the N in the surface layer of the soil occurs as fixed NH4+.
The proportion generally increases with depth, and in some subsoils
as much as 50% of the N may exist in this form.
The distribution of fixed NH4+ in representative soils of several
great soil eroups is shown in Figure 8.4. With the exception of the
Pcdzols, the A, horizons contained about 60 to 150 ppm of fixed
NH^-N, equivalent to about 120 to 300 Ib of N per acre plow depth
of soil. The rooting zone may contain as much as 1,600 Ib of N per
-------
132 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
FIG. 8.4. Distribution of
fixed NrV-N in soils rep-
resentative of several
"great soil groups."
(Adapted from Stevenson
and Dhariwal, 1959.)
FIXED NH4-N,PPM
100 200
300
RED-YELLOW
PODZOLIC
GRAY-BROWN
PODZOLIC
300
acre as fixed NH4+. The fixed NH4+ content is related to clay mineral
composition; soils rich in micaceous (illitic) types contain the largest
amounts.
The proportion of the soil N as fixed NH4+ increases slightly
when soils are cropped, indicating that the native fixed NH4+ is less
available to plants and microorganisms than the humus N. Increases
in the content of fixed NH4+ have been reported through N fertiliza-
tion (Harmsen and Kolenbrander, 1965).
Fixation of NH3 by Organic Matter
It is well known that NH3 can be "fixed" by reaction with lignins
and humic substances (Mortland and Wolcott, 1965; Broadbent and
Stevenson, 1966). Fixation is associated with oxidation (uptake of
oxygen) and is favored by an alkaline reaction. Thus, the applica-
tion of alkaline fertilizers such as aqueous- or anhydrous NH3 to
soil may result in considerable fixation. The NH3 fixed by organic
matter is not immediately usable by plants, although it does become
available eventually through the mineralization process.
The nature of the reaction of NH3 with soil humus is not
known. It is believed, however, that aromatic compounds containing
two or more hydroxyl groups are involved. The initial step involves
the consumption of oxygen and the formation of a quinone, which
subsequently reacts with NH3 to form complex polymers. Catechol
(I), for example, is readily converted in alkali to o-quinone (II),
which can be hydrated to form benzenetriol (III) (see Mortland and
Wolcott, 1965). Further oxidation yields o-hydroxyquinone (IV) and
p-hydroxy-o-quinone (V).
-------
CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 133
The incorporation of NH3 into p-hydroxy-o-quinone (V) is postu-
lated to produce structures of the types represented by VI and VII.
VI
OH
VII
Nitrite
Nitrite is not usually present in detectable amounts in well-
drained neutral or slightly acidic soils. Accumulations occur, how-
ever, in calcareous soils, and recent work indicates that this ion
often persists, albeit temporarily, when NH4+- or NH4+-type fertilizers
are applied to soil. This NO2- accumulation has been attributed to
inhibition of nitrification at the NO2~ stage. Presumably, NO2~ oxi-
dizing organisms (Nitrobacter) are more sensitive to NH3 and an
adverse soil reaction than NH4+ oxidizers (Nitrosomonas). According
to Hauck and Stephenson (1965), large fertilizer granules, high appli-
cation rates, and an alkaline pH in the zone of fertilization are par-
ticularly favorable for NO2~ accumulations.
The possibility that gaseous loss of fertilizer N may accompany
temporary N02~ accumulations has been mentioned in the reviews
of Allison (1965) and Broadbent and Stevenson (1966). Classical
reactions involving NO
-------
134 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
promote the decomposition of NOLr. One theory is that organic con-
stituents are involved (Broadbent and Stevenson, 1966; Bremner
and Nelson, 1968). Another view is that metallic cations are respon-
sible (Wullstein, 1967).
ORGANIC FORMS OF N
The organic N in soil consists of two main groups of com-
pounds: (1) nitrogenous biochemicals synthesized enzymatically by
microorganisms living on plant and animal residues, and (2) products
formed by secondary synthesis reactions and which bear no re-
semblance to any of the substances occurring in plant and animal
tissues. The N in the second group probably exists as part of the
structures of the so-called humic and fulvic acids. The two groups
are not easily separated, because some of the biochemicals (e.g., amino
acids) may be covalently bound to the humic matter.
Nitrogenous Biochemicals
AMINO ACIDS
The recent application of chromatographic methods to studies
of soil N have resulted in the isolation of an impressive number of
amino acids from soil hydrolysates, and these studies have confirmed
earlier reports indicating that 20 to 50% of the organic N occurs in
the form of amino acids (Bremner, 1965, 1967). In addition to the
20 to 22 amino acids generally found in proteins, a variety of other
compounds have been identified, including a-amino-n-butyric acid,
y-aminobutyric acid, (3-alanine, a,£-diaminopimelic acid, and 3,4-di-
hydroxypbenylalanine. The occurrence of a,f,-diaminopimelic acid
is of particular interest because this amino acid appears to be con-
fined to certain bacteria, where it occurs as a structural component
of the cell wall. The presence of ornithine, f5-alanine, and y-amino-
butyric acid in a variety of natural products is now well established.
Many unidentified ninhydrin-reacting substances have also been
detected in soil hydrolysates. Thus far, over 50 compounds have
been reported; the identity of the majority has not been established.
Some of the amino compounds may be artifacts produced during
hydrolysis.
The persistence of certain microbially synthesized amino acids
has been reported by Wagner and Mutatkar (1968) in a study of the
humification of 14C glucose. The highest specific activities were
found in those amino compounds known to be constituents of cell
walls of microorganisms (alanine, glycine, glutamic acid, and lysine).
Glucosamine, an amino sugar found in bacterial and fungal cell
walls, also contained large quantities of 14C. The cell walls of cer-
tain dark pigmented (melanic) fungi appear to be especially resistant
to deccmposition (Hurst and Wagner, 1969).
The reviews of Bremner (1965, 1967) show that conflicting
results have been obtained concerning the relative distribution of
-------
CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 135
amino acids in different soil types and between various horizons of
the same profile. Data obtained for the Morrow Plots at the University
of Illinois indicate that basic amino acids are selectively preserved
through long-time cropping; this trend has yet to be confirmed. Varia-
tions in amino acid composition may exist between soils from dif-
ferent climatic regions of the earth.
Considerable controversy exists as to whether proteins as such
occur in significant amounts in soil organic matter. The well-known
ligno-protein theory advanced by Waksman has yet to be confirmed;
many investigators believe that the theory in its original form is ob-
solete. Swaby and Ladd (1962) failed to detect proteins in humic
acids, using sensitive chemical tests, and concluded that neither
proteins nor ligno-protein complexes accounted for a significant part
of the soil N, On the other hand, results obtained using proteolytic
enzymes, partial hydrolytic procedures, and infrared spectrophotom-
etry suggests that in some humic acids peptide linkages are present.
Some of the amino acid-N in soil may occur as mucopeptides. Free
amino acids have but a transitory existence, and the amount of N in
this form rarely exceeds more than a few ppm.
The relative importance of clay and humus particles in binding
amino acids, peptides, and proteins is unknown. However, for the
surface layer of normal agricultural soils, the role played by humic
and fulvic acids cannot be overemphasized. In argillaceous sub-
soils, a significant proportion cf the proteinaceous material may be
held by clay minerals, perhaps on interlamellar surfaces.
AMINO SUGARS
Several studies have indicated that 4 to lOTc of the N in the
surface layer of the soil occurs in the form of N-containing carbohy-
drates, namely, the amino sugars. In some soils, the proportion may
increase with depth. Amino sugars are widely distributed in microbial
tissues; hence, their presence in soil is to be expected.
Research conducted at the University of Illinois indicates that a
wide variety of amino sugars are present in soils, including glucosa-
mine, galactosamine, fucosamine, and muramic acid. The latter is a
common constituent cf the cell walls of bacteria. Free amino sugars
have yet to be found in soils.
OTHER BIOCHEMICALS
A wide array of naturally occurring nitrogenous compounds
other than amino acids and amino sugars have been found in soils.
but in very low amounts. They include a variety of amines, several
chlorophyll derivatives, amino acid amides (asparagine and gluta-
mine), and purine and pyrimidine bases. All of these compounds
combined account for no more than 1 to 2^ of the soil N (Bremner,
1965, 1967).
-------
136 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Unknown Forms of Organic N
The considerations mentioned in the previous section emphasize
that no more than one-half of the soil organic N can be accounted for
as amino acids, amino sugars, purine and pyrimidine bases, and
other known compounds. Since practically all of the organic N in
soil is of microbial origin, and because the N of microbial tissues
occurs almost exclusively in the above-mentioned compounds, the
conclusion seems justified that during humification, conversion of
the microbially synthesized products to more stable humus forms has
occurred. The N content of humic and fulvic acids varies widely,
values between 0.4 and 5.0% having been reported.
The relative distribution of the forms of N in acid hydrolysates
of humic and fulvic acids is illustrated in Figure 8.5. It as note-
worthy that as much as one-third of the N in humic acids cannot be
solubilized by hydrolysis with 6 N HC1; as much as one-half of that
in fulvic acids is liberated as NH:V The nature of this N is uncertain,
but most of it may occur as part of the structures of humic sub-
stances.
In considering the properties of humus N, some discussion of the
nature of humic and fulvic acids is desirable. These constituents can
best be described as a series of acidic, yellow- to black-colored, moder-
ately high-molecular-weight polymers which have characteristics un-
like any organic compounds occurring in living organisms. The mod-
ern view is that they represent a heterogeneous mixture of molecules
which range in molecular weight from as low as 2,000 to perhaps
over 300,000. Interrelationships between such properties as color,
elemental composition, acidity, degree of polymerization, and molec-
ular weight are outlined schematically in Figure 8.6. No sharp divi-
sion exists between the various fractions.
60
FIG. 8.5. Relative distri-
bution of the forms of N
in humic and fulvic acids.
The broken portion of the
bars indicates the range of
values reported.
40
20
r f
sii
yi
M
r
j«J
A-HUMIC ADDS
B - FULVIC ACIDS
Amino ocid-N
NH-N
Acid Amino
insolubte-N sugar-N
-------
CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 137
Fulvic acid
Light yellow
Yellow-brown
Humic acid
Dark brown
Gray-black
increase in degree of polymerization
2,000? increase in molecular weight 1
45% increase in carbon content
48% decrease in oxygen content •
1, 400 decrease in exchange acidity
FIG. 8.6. Chemical properties of humic and fulvic acids. The yellow-
colored fulvic pigments are relatively mobile and can act as carriers
of N in streams and lakes (see text). (Adapted from a drawing by
Scheffer and Ulrich, 1960.)
The yellow-colored pigments shown in Figure 8.6 correspond to
the crenic and apocrenic acids of Berzelius, and they are the con-
stituents often found in the colored waters of lakes and streams. Be-
cause of their low molecular weights, fulvic acids are highly mobile
and can migrate through the soil profile in percolating waters.
The N of soil humic substances may occur in the following
forms:
1. As a free amino (—NFL) group
2. As an open chain (-NH-, — N-) group
3. As part of a heterocyclic ring, such as an —NH— of indole and
pyrrole or the —N= of pyridine
4. As a bridge constituent (see structures VI and VII)
Very little is known regarding the manner whereby N is in-
corporated in humic and fulvic acids, but one or more of the processes
illustrated in Figure 8.7 (and discussed below) are probably involved.
FIXATION OF NH3 BY OXIDIZED LIGNINS
The interaction between NH3 and oxidized lignins has been
suggested as a possible pathway of humus formation. The autoxida-
tion of both humic acids and lignin under alkaline conditions in the
presence of aqueous NH3 yields stable N-containing complexes. Re-
actions of the type discussed earlier are probably involved. Part of
the fixed N cannot be solubilized by subsequent acid hydrolysis.
POLYMERIZATION OF QUINONES WITH AMINO ACIDS
Many scientists now support the theory that humic constituents
originate through condensation of quinones with N-containing com-
pounds, such as amino acids. According to this concept, polyphenols,
either derived from the biological breakdown of lignin or synthesized
-------
138 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
PLANT RESIDUES
TRANSFORMATION BY MICROORGANISMS
MODIFIED
LIGNINS
SUGARS POLYPHENOLS
AMINO
COMPOUNDS
HUMIC SUBSTANCES
LIGNIN
DECOMPOSITION
PRODUCTS
I
QUINONES
FIG. 8.7. Mechanisms of formation of soil humic substances. Nitrog-
enous substances (e.g., amino acids) synthesized by microorganisms
during the decomposition of plant and animal residues are seen to
react with modified lignins (reaction 4), quinones (reactions 2 and 3),
and reducing sugars (reaction 1) to form complex polymers containing
N as part of their structures.
by microorganisms, are oxidized enzymatically by phenoloxidases to
quinones, which then react with amino acids to form humic sub-
stances. In the process, cyclic N compounds are formed.
Flaig's (1966) concept of humus formation is as follows:
1. Lignin, freed of its linkage with cellulose during decomposition
of plant residues, is subjected to oxidative splitting with the for-
mation of primary structural units (derivatives of phenylpro-
pane).
2. The side chains of the lignin-building units are oxidized, de-
methylation occurs, and the resulting polyphenols are converted
to quinones by polyphenoloxidases.
3. Quinones arising from the lignin (as well as from other sources)
react with N-containing compounds to form dark-colored poly-
mers.
The importance of microorganisms as a source of polyphenols
for humus synthesis has recently been emphasized. Kononova (1966),
for example, has postulated that humic substances can be formed
from polyphenols synthesized by cellulose-decomposing myxobacteria
in soil. Many fungi are known to produce humic acidlike substances.
According to Swaby and Ladd (1962) humic molecules are formed
from free radicals (quinones) produced enzymatically within deceased
cells while autolytic enzymes are still functioning but before cell walls
are ruptured by microbes.
CONDENSATION OF SUGARS AND AMINES
The formation of brown nitrogenous polymers by condensation
of carbonyl-containing compounds (reducing sugars) and amino
-------
CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 139
derivatives (amino acids) occurs extensively in stored food products
and the reaction has been postulated to occur in soils. A major
objection to this theory is the slow rate at which sugar-amine con-
densation reactions occur. However, drastic changes in the en-
vironment (freezing and thawing, wetting and drying), together with
the intermixing of reactants with mineral material having catalytic
properties, may facilitate condensation.
EFFECT OF CULTIVATION OF THE N DISTRIBUTION IN SOILS
It is well known that the N content of most soils declines when
land is cultivated for the first time. Under average farming condi-
tions in the Corn Belt region of the United States, about 25% of
the N is lost the first 20 years, about 10% the second 20 years, and
about 1% the third 20 years. This loss of N is not spread uniformly
over all of the N fractions. Long-time cultivation has been found
to result in increases in the proportion of the total N as fixed NH4+,
amino sugars, and hydrolyzable N. The changes are small, however,
and no single component can be considered to be the major source
of mineral N for plant growth. Methods of estimating available N
by analysis of any given fraction would appear to be unsatisfactory.
Research conducted at the University of Illinois indicates that
when soils are cropped those compounds intimately bound to clay
minerals are selectively preserved. Figure 8.8 shows that the propor-
tion of the organic N in the Morrow Plots which was solubilized
through destruction of clay with HF increased with decreasing N
content. Thus, it appears that loosely bound substances are lost
first, followed in order by those held by strong cohesive forces. The
content of soluble organic N compounds in drainage waters would
be expected to be particularly low in soils from intensively cultivated
areas.
50r
40-
Q
UJ
o
30-
x
u
20-
HI EXCH. NH4-N
CONT.C Q FIXED NH^-N
-
',
Ff
* 1
f
: -
IP
, '
M
11 ORG.-N
C
-C
m
r''
Id
s
t:
'
s t
^n
>
cc
N
)N1
«LF
J
29
>O
j-
1
: c
G~"0"Cl MI p
as
""
^ ^
i
r'**-'^
sn?
?
' B
1
BORDER
c-
W
0-(
LP
cs
~
23
1
;i
zn
n
S
R
^
i ^
fi
i
FIG. 8.8. Organic N and
NHr extracted from the
Morrow Plot soils by
extraction with a 2.5N-
HF:0.1N-HCI solution. The
values in the solid portion
of the bars represent the
percent recovery of or-
ganic N. C — corn, O =
oats, Cl = clover, MLP =
manure, lime, and phos-
phate. (From Stevenson
et al., 1967.)
%N = 0.128 0.158 0.163 0.135 0.212 0.243 0.290
-------
140 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Figure 8.8 further shows that the percentage of the total N
as fixed NH4+ was highest in those soils where organic matter had
been depleted through intensive cultivation (see section on Naturally
Occurring Fixed NH4+).
SUMMARY
This brief review has served to emphasize the complex nature
of soil N. Other than gaseous forms, the inorganic N consists pri-
marily as NH4+ and NO;{-. Part of the NH4+ is bound to colloidal
surfaces and behaves according to classical reactions of exchange
chemistry. Nitrate is free to move with the soil water and is the
form of N which is of greatest concern from the standpoint of
pollution of water supplies. Many soils contain appreciable amounts
of NH4+ that cannot be utilized directly by plants and microorga-
nisms; this NH4+ is held within the lattice structures of clay minerals.
Less than one-half of the organic N in soils can be accounted
for in known compounds (amino acids, amino sugars, purine and
pyrimidine bases, etc.). The remainder may occur as part of the
structures of humic and fulvic acids. Part of the N added to soils
as fertilizers can be converted to organic forms by chemical reactions
involving NH,S and NO2-; this combined N is only slowly mineralized
and may persist in soil for prolonged periods.
Bacterial denitrification is an important factor regulating NO;!"
levels in natural soil and may serve as a means of reducing the NO3-
content of groundwater when land is used for the disposal of
nitrogenous wastes.
REFERENCES
Allison, F. E. 1965. Evaluation of incoming and outgoing processes
that affect soil nitrogen. In Soil nitrogen, ed. W. V. Bartholo-
mew and F. E. Clark, pp. 573-606. Madison, Wis.: Am. Soc.
Agron.
Bremner, J. M. 1965. Organic nitrogen in soils. In SoiZ nitrogen,
ed. W. V. Bartholomew and F. E. Clark, pp. 93-149. Madison.
Wis.: Am. Soc. Agron.
. 1967. Nitrogenous compounds. In Soil biochemistry, ed.
A. D. McLaren and G. H. Peterson, pp. 19-66. New York: Mar-
cel Dekker.
Bremner, J. M., and Nelson, D. W. 1968. Chemical decomposition
of nitrite in soils. Trans. 9th Intern. Congr. Soil Sci. Australia
2:495-503.
Broadbent, F. E., and Clark, F. 1965. Dentrification. In Soil nitro-
gen, ed. W. V. Bartholomew and F. E. Clark, pp. 344-59.
Madison, Wis.: Am. Soc. Agron.
Broadbent, F. E., and Stevenson, F. J. 1966. Organic matter inter-
actions. In Agricultural anhydrous ammonia: technology and
use, ed. M. H. McVickar et al., pp. 169-87. Madison, Wis.:
Am. Soc. Agron.
Flaig, W. 1966. The chemistry of humic substances. In The use of
isotopes in soil organic matter studies, pp. 103-27. New York:
Pergamon Press.
-------
CHAPTER 8 / CHEMISTRY OF NITROGEN IN SOILS / 141
Harmsen, G. W., and Kolenbrander, G. J. 1965. Soil inorganic nitro-
gen. In Soil nitrogen, ed. W. V. Bartholomew and F. E. Clark,
pp. 43-92. Madison, Wis.: Am. Soc. Agron.
Harmsen, G. W., and van Schreven, D. A. 1955. Mineralization of
organic nitrogen in soil. Advan. Agron. 10:299-398.
Hauck, R. D., and Stephenson, H. F. 1965. Nitrification of nitrogen
fertilizers. Effect of nitrogen source, size and pH of the granule,
and concentration. Agr. Food Chem. 13:486-92.
Hurst, H. M., and Wagner, G. H. 1969. Decomposition of 14C-
labeled cell wall and cytoplasmic fractions from hyaline and
melanic fungi. Soil Sci. Soc. Am. Proc. 33:707-11. '
Hutchinson, G. L., and Viets, F. G., Jr. 1969. Nitrogen enrichment
of surface water by absorption of ammonia volatilized from
cattle feedlots. Science 166:514-15.
Kononova, M. M. 1966. Soil organic matter, 2nd ed. New York:
Pergamon Press.
Meek, D. B., Grass, L. B., and MacKenzie, A. J. 1969. Applied nitro-
gen loss in relation to oxygen status of soils. Soil Sci. Soc. Am.
Proc. 33:575-78.
Mortland, M. M., and Wolcott, A. R. 1965. Sorption of inorganic
nitrogen compounds by soil minerals. In Soil nitrogen, ed.
W. V. Bartholomew and F. E. Clark, pp. 150-97. Madison,
Wis.: Am. Soc. Agron.
Nommik, H. 1965. Ammonium fixation and other reactions involv-
ing a nonenzymatic immobilization of mineral N in soil. In
Soil nitrogen, ed. W. V. Bartholomew and F. E. Clark, pp.
198-258. Madison, Wis.: Am. Soc. Agron.
Scheffer, F., and Ulrich, B. 1960. Humus und Humusdiingung. Bd.
1. Stuttgart, Germany: Ferdinand Enke.
Smith, G. E. 1968. Contribution of fertilizers to water pollution.
In Water pollution as related to agriculture, pp. 13—28. Paper
presented at joint seminar, Univ. of Mo., Columbia, and Mo.
Water Pollution Board, Columbia.
Stevenson, F. J. 1965. Origin and distribution of nitrogen in soil.
In Soil nitrogen, ed. W. V. Bartholomew and F. E. Clark, pp.
1-42. Madison, Wis.: Am. Soc. Agron.
Stevenson, F. J., and Dhariwal, A. P. S. 1959. Distribution of fixed
ammonium in soils. Soil Sci. Soc. Am. Proc. 23:121—25.
Stevenson, F. J., Kidder, G., and Tilo. S. N. 1967. Extraction of
organic nitrogen and ammonium from soil with hydrofluoric
acid. Soil Sci. Soc. Am. Proc. 31: 71-76.
Stewart, B. A., Viets, F. G., Jr., Hutchinson, G. L., and Kemper, W. D.
1967. Nitrate and other water pollutants under fields and feed-
lots. Environmental Sci. Tech. 1:736-39.
Swaby, R. J., and Ladd, J. N. 1962. Chemical nature, microbial
resistance, and origin of soil humus. Trans. Intern. Congr. Soil
Sci. (New Zealand), Com. IV and V, pp. 197-202.
Wagner, G. H., and Mutatkar, V. F. 1968. Amino components of soil
organic matter formed during humification of 14C glucose. Soil
Sci. Soc. Am. Proc. 32:683-86.
Wetselaar, R. 1962. Nitrate distribution in tropical soils. III. Down-
ward movement and accumulation of nitrate in the subsoil.
Plant Soil 14: 19-31.
Wullstein, L. H. 1967. Soil nitrogen volatilization. Agr. Sci. Rev.
2nd Quart., pp. 8-13.
-------
CHAPTER NINE_
FERTILIZER MANAGEMENT
FOR POLLUTION CONTROL
W. P. MARTIN, W. E. FENSTER, and L. D. HANSON
HE rapid increase in fertilizer usage has been due largely to
low fertilizer costs and the necessity for higher economic yields.
Reliance on legumes and the use of animal manures, both for
nitrogen and erosion control, have given way to chemical fertilizers
in many areas. This higher fertilizer usage has vastly increased crop
residues which, in themselves, tend to protect the soil surface and
improve soil structure for moderating erosion. Crop varieties, with
high yield potentials, have also played a major role in increased crop
production. In order for these new varieties to attain their maximum
yield potentials, increased fertilizer rates have been necessary. In
addition to farm uses, fertilizers are being used more on parks,
playgrounds, golf courses, home lawns, roadbanks, forest recreation
areas, and even in forest lands.
The rapid expansion in fertilizer use has raised many questions
concerning nutrient pollution of our surface and groundwaters.
Since the population of the United States is rapidly increasing, it
probably will be essential that our land acres produce food and fiber
at capacity levels in the future. This will necessitate the continued
rise of high rates of fertilizer. However, management practices must
be followed such that the high yields attained are also consistent with
a clean and safe environment.
FERTILIZER USE IN THE NORTH-CENTRAL STATES
In the east north-central states of Wisconsin, Michigan, Illinois,
Indiana, and Ohio, 8.1 million tons of fertilizers were used in 1968,
W. P. MARTIN is Professor and Head, Department of Soil Science,
University of Minnesota. W. E. FENSTER is Assistant Professor and
Extension Specialist in Soils, Department of Soil Science, University
of Minnesota. L. D. HANSON is Associate Professor and Extension
Specialist in Soils, Department of Soil Science, University of Minne-
sota.
Miscellaneous Publication Paper No. 1360 of the University of Min-
nesota Agricultural Experiment Station, St. Paul.
See Hargett (1969) for the statistics used in this section.
142
-------
CHAPTER 9 / FERTILIZER MANAGEMENT / 143
or an average of about 135 pounds of plant nutrients per acre on
some 56 million harvested acres, 32% of which was applied in the
fall. This is approximately four times the usage in 1945. Nitrogen
has shown the most spectacular increase, 46,000 tons in 1945 to 1.3
million tons in 1968, or almost 30 times as much.
In the west north-central states of North and South Dakota, Min-
nesota, Iowa, Nebraska, Kansas, and Missouri, 7.8 million tons were
used in 1968, or an average of about 65 pounds of nutrients per acre
on some 117 million harvested crop acres, and some 34% wras used
in the fall. This is approximately 17 times the usage in 1945 and
again nitrogen has shown the most spectacular gains, increasing from
less than 6,000 pounds in 1945 to over 2 million pounds in 1968,
over 300 times as much.
The north-central states are among the high-use states, and in
the western and central parts the rapid expansion of irrigation enter-
prises is accelerating the use of fertilizer nutrients to maximize pro-
duction. Projection estimates suggest further expansion, perhaps
even a doubling in fertilizer use in the next 15 years, so that the Mid-
west will account for some 40% of the total used in the United States
(Beaton and Tisdale, 1969).
Although the aforementioned figures are spectacular in terms
of increasing usages of plant nutrients in fertilizers, their utilization
by crops must be balanced against the pollution aspects of the soil-
water system. Many of these factors have been covered in great
detail in the preceding chapters, however, it will be necessary to pro-
vide modest documentation in order to relate principles of soil and
crop management for production to the problem of minimizing po-
tential pollution of water supplies from use of fertilizers (Soileau,
1969). The discussion will be confined to nitrogen and phosphorus,
the two nutrient elements of principal concern in water pollution
and eutrophication.
FERTILIZER USE VS CROP HARVEST REMOVALS
It should be pointed out that our cropping programs have, in
general, been exploitive of plant nutrients and that we are still re-
moving more nutrients than are being replaced by way of fertilizers,
or from other sources. White (1965) evaluated the situation and es-
timated that major crops in the United States on our 294 million
cropped acres were removing about 8.8 million tons of nitrogen (in-
cluding nitrogen fixed in leguminous plants of approximately 3 mil-
lion tons) and 2.8 million tons of phosphate. Only in the case of
phosphorus are the additions equivalent to the withdrawals, and
when it is considered that crop use efficiencies are substantially less
than 50% of that applied, we are still "mining" rather than "enrich-
ing" our soils with plant nutrients.
Stanford (Wadleigh, 1968) has estimated that in the past 100
years there has been a loss of organic matter in the top 40 inches of
the cropped agricultural soils of the United States of some 35 billion
tons, or a loss of 1,750 million tons of organic nitrogen. Nitrogen fer-
-------
144 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
tilizer application, though appearing to be large and now approaching
annual crop removal levels, is small in terms of "historical losses."
In Minnesota, for example, on approximately 18 million acres of
cropland, nitrogen withdrawals average close to a million tons an-
nually and phosphorus some 200,000 tons. Less than a quarter of
this amount is being added by way of fertilizers, so even taking into
account nutrients added through manures and legumes, two to three
times as much chemical fertilizer could be justified for crop produc-
tion at current levels.
It is evident, however, that we may reach application levels
where the additions of plant nutrients surpass crop removals and in
Iccal situations now, very high application rates of nitrogen par-
ticularly are sometimes noted (Beaton and Tisdale, 1969). It is pos-
sible to enrich local water supplies, especially where soils are not
adequately protected from erosion. It is necessary, therefore, that
attention be given now to those management factors that can assure
the crop production needed and at the same time minimize the
potential for nutrient pollution.
EROSION AND SEDIMENTATION
The conservation movement of the past 30 years has stimulated
and supported a major research effort which has documented the
seriousness of erosion and sedimentation both from the standpoint of
land destruction and water degradation. It has been estimated that
some 4 billion tons of sediment are washed into waterways and reser-
voirs annually; this is equivalent to about 4 million acres of good top
soil 6 inches deep (Stallings, 1957; Smith and Wischmeier, 1962;
Wadleigh, 1968). Marked abatement of this erosion and sediment de-
livery can be accomplished by erosion control structures, crop rota-
tions, use of minimum tillage, and utilization of crop residues both by
incorporation to improve structure and by mulching to protect soil
surfaces.
Smith and Wischmeier (1962) developed a "universal rainfall
erosion equation" by integrating data from some 35 field research sta-
tions. This equation aids in management decisions designed to keep
soil losses in the field below established "tolerance" limits of 3 to 4
tons per acre annually. The equation identifies key determinants in
soil loss and sediment delivery and defines them in terms of average
annual erosion-producing rainfall, soil erodibility, topography, crop-
ping and cultural practices, and erosion control activities (Ballantyne
et al., 1967). In the future these activities will likely take on the
increasingly important role of controlling lake-destroying sediments.
A further consideration of interest is the nutrient aspects of the
land sediments reaching water. Most researchers have felt that just
as fertile soils produce more land plants via higher equilibrium levels
of available nutrients, so do fertile sediments provide more nutrients
for aauatic plants.
The physical removal of nutrient elements by erosion is non-
selective in the sense that the elements may be removed in any chemi-
cal form. The process, however, tends to be selective in that the
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CHAPTER 9 / FERTILIZER MANAGEMENT / 145
organic matter and finer particles of soil are more vulnerable to
erosion than are the coarser soil fractions (Barrows and Kilmer, 1963),
Organic matter is among the first constituents to be removed because
of its low density and high concentration in surface soils. Hays et al.
(1948) reported 951 pounds per acre of organic matter lost annually
from moderately eroded Fayette silt loam and 668 pounds from a
severely eroded phase. Significant quantities of nitrogen and phos-
phorus may be removed in the organic phase. Massey and Jackson
(1952) calculated regression equations for the enrichment ratios of
organic matter and plant nutrients from Almena, Fayette, and Miami
soils in Wisconsin, using runoff plot and small watershed data, and
concluded that they were removed selectively in the following order:
organic matter, organic and ammoniacal nitrogen, and finally "avail-
able" phosphorus.
Losses reported for soluble nitrogen salts and unreacted phos-
phatic fertilizer compounds in runoff waters are exceedingly low
and appear to be of little significance (Barrows and Kilmer, 1963;
Biggar and Corey, 1968; Wadleigh, 1968). However, existing data
are insufficient to evaluate the influence of such factors as source,
rate, placement, and time of application of fertilizer relative to the
occurrence of runoff. Hauser (1968) recently sampled closed playas
on the Texas high plains entrapping runoff waters from heavily fer-
tilized adjacent fields and found them virtually free of nitrates.
Samples taken on five different sampling dates contained less than
0.5 ppm of nitrate nitrogen, on an average, and the same values
were recorded for playas whose watersheds were 95% native grasses.
Rogers (1942) applied triple superphosphate at the rate of 200
pounds per acre to Dunmore silt loam in permanent pasture, followed
immediately by a series of 1-inch rains from a rainfall simulator.
The first rain removed 9.1% of the applied phosphorus and the
second 4.3% . As much as 22% of the phosphorus applied to a dry
bare soil was removed when rain \vas applied immediately after fer-
tilization. Phosphorus solution and immobilization by soil fixation
could not occur with sufficient rapidity under these extreme condi-
tions to prevent some loss in the runoff waters.
It is evident that erosion can and does in many instances cause
significant losses of soil and organic matter with concomitant removal
of nitrogen and phosphorus. Previously mentioned erosion control
measures can reduce these losses by 75% and more (Wadleigh,
1968).
PHOSPHORUS IN SOIL AND NATURAL WATER SUPPLIES
Recently there has been increased appreciation of the sig-
nificance of phosphorus in the process of lake eutrophication (Megard,
1969). The nitrogen-fixing capability of blue-green algae often dimin-
ishes the significance of nitrogen as a nutrient and increases that of
phosphorus. The phosphorus regimes in soil versus water vary
markedly in that only a small portion of the soil phosphorus is in an
available form, whereas that in water is almost totally available. The
amount of phosphorus in soils is, therefore, much larger than that in
-------
146 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
our natural waters. Soils may vary from 100 to 4,000 pounds of
total phosphorus (1,000 pounds per acre average) in the plow layer,
only 5 to 10% of which contributes to the "labile pool" of potentially
available phosphorus (Bailey, 1968; Black, 1968). An example of a
quantity of phosphorus contained in a Minnesota lake to a depth
where light was sufficient for photosynthesis is 2.8 pounds per acre.
This amount is sufficient for profuse algae growth (Megard, 1969).
Lysimeter and other types of experiments have demonstrated
that phosphorus does not significantly leach downward as a result of
water percolation; drainage waters thus contain small concentrations.
The highest amount reported was that in California on well-drained
soils receiving large amounts of fertilizer and water by w^ay of irriga-
tion, where Johnston et al. (1965) recorded a mean concentration of
0.08 ppm of phosphorus in the irrigation drainage. Water moving
into natural waters from underground flow will contain phosphorus
at levels consistent with those found generally in uncontaminated
waters or from 0.01 to 0.03 ppm (Maderak, 1963). Agricultural land
drainage is usually in this same range (MacGregor and Hanson,
1969).
The magnitude of runoff and sediment sources of phosphorus is
under extensive investigation at the present time. Past work has
tended to emphasize erosion.
Many experiments on soil loss from erosion have been carried
on by the Missouri Agricultural Experiment Station, dating from 1917
(Duley and Miller, 1923). In an experiment on Shelby loam, with
plots 90 feet long and having a 3.86% slope, loss of phosphorus by
erosion was 18 pounds per year with continuous corn and 6.2 pounds
with a good rotation of corn, wheat, and clover. Under continuous
bluegrass, only 0.1 pound of phosphorus was lost by erosion, demon-
strating the effectiveness of plant protection against soil loss (Miller
et al., 1932).
Bedell et al. (1946) demonstrated the loss of organic phosphorus
through erosion. Where corn was grown under prevailing manage-
ment practices, over 4.5 tons of solids were removed per acre, carry-
ing approximately 20 pounds of phosphorus. Nearly 60% of the
phosphorus lost was in the organic form. Eroded soil from natural
runoff-erosion plots on a Barnes loam soil, 7% slope, at Morris, Min-
nesota, contained 500 to 2,000 ppm total P (Timmons et al., ]968).
These were agricultural soils which had been adequately fertilized,
and cropping patterns varied from clean-cultivated fallow, through
continuous corn to corn-oats-hay in rotation.
Recent studies have indicated that lake sediments are not con-
tributing to lake water pollution by supplying phosphate and indeed
will be able to extract phosphate from the waters with which they
come in contact. The phosphate potential for lake bottom sediments
from several western Minnesota lakes with varying degrees of
eutrophication were determined and the "index" factors were found
to vary from 8.22 to only 8.59, indicating a high degree of phosphate
adsorption capacity (White and Beckett, 1964; Holt et al., 1969;
Latterell et al., 1969).
The runoff source of phosphorus appears to be more important
than was previously suspected. Of particular interest is Holt's (1969)
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CHAPTER 9 / FERTILIZER MANAGEMENT / 147
observation that spring snow melt waters carry much higher amounts
of phosphorus than runoff waters during other times of the year as
measured on natural-rainfall-runoff plots. This is presumably coming
from plant residues that have been frozen over winter, allowing the
nutrients to be washed out in the spring. Also, soil contact is pre-
vented by a mat of organic material on the soil surface and the
frozen soil itself. Amounts, though small, were five to six times higher
in snow melt runoff than in water percolating through the soil. This
observation was supported by Hanson and Fenster (1969) in data
comparing the phosphorus concentration of tile line waters (soil
percolation) and adjacent drainage ditch waters (percolation plus
snow melt) in the spring of 1969 for sampling sites on 20 farms in
southern Minnesota's corn- and soybean-growing area. Soils at the
sampling sites were Webster and Glencoe clay loams. Tile line out-
let waters averaged 0.03 ppm phosphorus vs. 0.16 ppm for the ad-
jacent ditches, or five times as much.
It will be difficult to intercept snow melt runoff coming off the
large areas of natural grasslands. Diversion of surface runoff waters
to seepage areas may in some instances be feasible, but often at con-
siderable expense. Water which has percolated through a mineral
soil is essentially stripped of its soluble and particulate phosphate
and will not be a significant source of phosphorus in natural water
supplies whether or not it comes from fertilized or unfertilized soils.
Land leveling, retention terraces, and other erosion control measures
can be designed to help on cultivated soils. Spreading of fertilizer
and manures on frozen soils on rolling land adjacent to water supplies
should be avoided (Corey et al., 1967).
MANAGEMENT OF SOIL NITROGEN
In many ways the questions raised concerning fertilizer manage-
ment for control of pollution are premature in that water quality
benchmarks for lake eutrophication or for public and animal health
have not been jointly established or agreed upon. However, regard-
less of interpretation with respect to these two facets of the problem,
it is important that nitrogen movement and losses be reviewed as
related to land management activities. Most modern crop production
practices will affect the soil nitrogen regime in some degree and it is
difficult to generalize about them because of the complex nature of
the soil-climate-plant system. Interactions among soil, climate, irriga-
tion, drainage, tillage, fertilizer, and crop are exceedingly complicated
and becoming more so with rapidly changing patterns of fertilizer
use and tillage methods.
Nitrogen in the Soil
Tillage is a significant factor in the release of nitrogen, since it
markedly speeds up oxidation of organic matter with release of, and
subsequent nitrification of, ammonia. The high organic matter soils
of the north-central states containing 0.2 to 0.4% by weight of
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148 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
nitrogen have a potential for production of nitrate which is sub-
stantial, and yields of 200 to 400 pounds per acre annually without
supplementary nitrogen were not uncommon during the early years of
cultivated agriculture in the region (Black, 1968). To a large extent,
nitrogen fertilizers as currently used can be considered a replacement
for lower "yields" of tillage-induced soil-organic-matter-released nitro-
gen. From this perspective, chemical nitrogen fertilizer use is not
essentially different from the older agronomic practices of cultivation
and the use of legumes and animal manures to shift the nitrogen
equilibrium in favor of the crop plant.
Allison (1955, 1965) has extensively reviewed nitrogen balances
in soils and concludes that as long as it remains in the organic form
it is comparatively safe from loss except through erosion. Normally,
however, as noted above, soil organic nitrogen is slowly converted to
ammonia by heterotrophic soil microorganisms and then into nitrites
and nitrates by the nitrifying bacteria, and in these forms it is subject
to the same losses as nitrogen from fertilizer sources. In the absence
of a crop or leaching, as much as 5 to 10% of the nitrogen may ac-
cumulate as nitrate during a 6-month period in cultivated soils. A
crop such as corn removes 2 to 3% of the nitrogen in the plow layer
during one growing season. Small grain crops remove half as much
as corn. Nitrogen returned to the soil in crop residues may contribute
as much as 20% of the total nitrogen assimilated by the crop.
Many investigators, using lysimeters, have reported on leaching
losses of nitrogen in the form of nitrates (Bizzel, 1944; Allison, 1955,
1965; Allison et al., 1959; Black, 1968; Webber, 1969b). Allison
(1955), for example, summarized the results of 157 lysimeter experi-
ments conducted at several locations in the United States. These in-
cluded 51 lysimeters kept fallow and 106 that were cropped to non-
legumes. The unaccounted-for nitrogen averaged 15% of that added
or which became available in the soil. He noted that this nitrogen
loss could not be assigned to denitrification, which under normal soil
conditions is quite small. Nitrogen recovered in the crop from added
fertilizer nitrogen, or from that which became available in the soil,
was usually less than 50% . Significantly, however, Pearson et al.
(1961) showed that equivalent nitrogen recoveries for three successive
crops ranged from 70 to 77% in the humid southeast if nitrogen was
applied at a time when leaching was at a minimum and when crops
were present to effect assimilation. Two hundred pounds of nitrogen
per acre were applied to corn in the spring with two additional crops
being grown during the following 16 months. It was concluded that
in general, leaching losses of nitrogen are small if an actively growing
crop is present at all times, and if the rate of nitrogen additions
clearly approximates the needs of the crop. If much nitrogen is added
or released as nitrate in the late fall, the losses are likely to be large
unless a cover crop or permanent sod is present.
Russell (1961) documents that nitrates are always lo\ver in
cropped land than under fallow, not only because the crop is ex-
tracting nitrate for growth but because the crop depresses the rate of
nitrification in soil. Nitrogen present in a cropped soil as nitrate and
in the crop was less than the nitrate in an adjacent fallow soil.
Nitrates accumulated during the spring and summer in the fallow
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CHAPTER 9 / FERTILIZER MANAGEMENT / 149
soil, but not in the cropped soil. Fallow soil also appeared to lose
substantial amounts of nitrates by early winter, presumably because
of leaching into the subsoil.
Smith (1968) in Missouri has also found that nitrates in small
amounts may reach groundvvater supplies. Soil samples in foot in-
crements were taken to a depth of 10 feet in Putnam silt loam which
had been in continuous corn for 20 years and had received 120
pounds of nitrogen as ammonium nitrate per acre annually. Nine
pounds per acre per year more nitrogen was found in the surface 10
feet of sell than where no nitrogen was applied. Other nitrate move-
ment studies have been underway for 7 years on soils with widely
different characteristics. Rainfall has ranged from 30 to 50 inches
per year and corn yields from 60 to more than 150 bushels per acre.
Nitrates in small amounts have accumulated progressively in the 8-
foot profile samples at all levels of application above 100 pounds per
acre except in the sandy soils where leaching has presumably moved
nitrates below the depth of sampling.
Higher nitrogen losses have been measured by Johnston (1965)
in connection with a study of tile drainage and wastewater manage-
ment in the San Joaquin Valley of California. He noted that 9 to
70% of the nitrogen applied just prior to the 1962 irrigation season
or with the irrigation water was lost either in the drainage effluent or
in the tailwater. It was noted that the presence of a continuous water
table at or above the tile systems was necessary to obtain the data
presented. Nitrogen rates varied from 84 to 260 pounds per acre and
crops were cotton and rice.
Gardner (1965) notes that the downward movement of water
through the "macropore systems" of medium-textured soils is rather
rapid. The larger the total pore volume of this system, the more
readily the water will move. The presence of a crop, however, tends
to reduce this downward movement because of evapotranspiration.
The crop, therefore, greatly minimizes leaching losses of nitrogen
both directly, by assimilation, and indirectly, by reducing the amount
of leachate.
A suggested way of evaluating probable leaching losses of nitrc-
gen and how to minimize them is to make use of precipitation-evapo-
transpiration curves as noted by Allison (1965). Using this approach,
for an example, the results for central Minnesota show that there is
little cr no leaching or movement of water through the soil during
the summer months, and during the winter months the soils are
fro/en. Fall and spring are the months when drainage occurs in the
Midwest (Blake et al., 1960). In drier regions of the Great Plains
states, the soil is rarely filled to field capacity beyond the root zone.
except under irrigation, and hence there will be little leaching of
nitrogen. These data emphasize the importance of a crop for mini-
mizing leaching losses and the importance of avoiding the accumula-
tion of nitrates in soils in late fall.
It should perhaps be noted that nitrates reaching the drainage
ditch, lake, or reservoir are either quickly used by plants or denitrify
in the anaerobic high-enerey environment of decomposing plant
materials (Allison, 1965). Keeney et al. (1969) were not able to
detect nitrates in Wisconsin lake sediments, nor are nitrates com-
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150 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
monly found in more than trace amounts in surface waters (Maderak,
1963).
Sources of Nitrate in Water Supplies
Natural sources of nitrogen, as well as those from fertilizers,
leguminous crops, and animal waste disposal operations, must be
evaluated for perspective in considering ways in which soil manage-
ment may minimize the nitrate pollution of water supplies. These
quantities are difficult to estimate, so considerable watershed monitor-
ing will be needed in the future. Unless additions of nitrogen from all
sources which go into a watershed are balanced by withdrawals such
as by harvest and removal of crops or denitrification, nitrate-nitrogen
will accumulate in surface water or groundwater (Stewart et al.,
1968).
Nitrate contamination of water supplies from barnyards or con-
centrated livestock feeding operations has been well documented and
corrective measures are being instituted in many states to moderate
the problem via collecting basins, oxidation trenches or lagoons, and
land spreading of the animal manures. Since the animal manures are
a source of plant nutrients released during decomposition, they are in
the same category as fertilizers when applied to cropland in evaluat-
ing management procedures which will minimize pollution.
Smith (1965, 1967) researched sources of nitrogen in some 6,000
rural water supplies in Missouri and concluded that animal wastes
and septic tank drainage coming from poorly constructed shallow
wells were the main sources of water contamination. He suggested
that fertilizer nitrogen was not at this time significant overall, though
in some instances application rates go beyond efficient crop utilization
levels.
In Minnesota, also, nitrate contamination of rural wells has
been noted for many years, long before nitrogen fertilizers were used
to any extent. Shallow wells in glacial drift and in the Shakopee and
Oneota dolomites, with recharge directly from the drift, are higher in
dissolved solids and often contaminated with nitrates above Public
Health Service standards. This occurs most notably in communities
without municipal sewage disposal systems and where large num-
bers of livestock are concentrated. However, recent summary reports
by the Minnesota State Department of Conservation (Maderak, 1965)
on the chemical quality of groundwaters show that wells from deep
aquifers such as the Jordan and St. Peter sandstones, with recharge
from the northern Minnesota lake and forest areas, are very low in
nitrates and dissolved solids. In general, change in the quality of
wrater for the major aquifers from 1899 to 1963 has been minor.
Schmidt (1956) studied the problem of anoxemia in very young
infants as related to nitrate contamination of rural wells varying in
depth from 15 to 50 feet in southern Minnesota's prairie soil area.
Soils obviously containing high levels of organic nitrogen from live-
stock had the highest nitrifying capacities, and water supplies with
concentrations of nitrate of 75 to 130 ppm were located near such
soils. Normal field soils were associated with subsoil drainage waters
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CHAPTER 9 / FERTILIZER MANAGEMENT / 151
of up to 18 ppm and well waters of up to 35 ppm nitrate. The high
organic matter soils of southwestern Minnesota present ideal condi-
tions for nitrification and release of nitrogen from the organic nitro-
gen complex with cultivation so that supplementary nitrogen from
animal manures or other sources can result in high nitrate produc-
tion which may move into shallow wells which are improperly located
or constructed. This illustrates that fertilizer rates applied must be
evaluated in terms of the "background" level of fixed nitrogen in the
soil water.
Stout and Burau (1967) studied nitrate accumulations in the
groundwaters of a closed 10-square-mile basin near San Luis Obispo,
California. This area, containing 2,700 intensively cropped acres, is
urbanized with 13,500 people and the domestic arid irrigation waters
are supplied exclusively from wells with a rapid recharge. These well
waters ranged from 5 to 130 ppm in nitrate. The nitrogen pool was
substantial and mostly associated with the native soil organic matter
complex supplemented with sewage waste from area homes and to a
lesser extent from lawn and farm fertilization. Cropland manage-
ment recommendations were developed by Stout and Burau to include
nitrogen fertilizer rates consistent with the needs of the crop, mostly
fruits and vegetables, and to include the amounts of nitrate-nitrogen
in the well waters which were used for irrigation. It was recommend-
ed that domestic waters be taken from prehistoric deep waters which
are unaffected by tillage and hydraulic sewage disposal systems.
One of the more recent and well-documented studies on sources
of pollution of underground supplies was made in the middle South
Platte River valley in Colorado (Stewart et al., 1968). This valley is
intensively farmed and irrigated, has some 600,000 cattle in feedlots,
and is surrounded by many cultivated dryland fields. Twenty-foot
cores from the soil surface to water table or bedrock from 10 to 65
feet deep were taken from 129 sites of differing land use and analyzed
for nitrates in transit. Average total nitrate nitrogen in pounds per
acre for land use types was as follows: alfalfa, 79; native grassland,
90; cultivated dryland, 261; irrigated fields not in alfalfa, 506; and
cattle corrals, 1,436 pounds. In general, there was extreme variation
within classes of land use. Calculations based on core averages and
rate of water movement through the profile under irrigation indicated
that 25 to 30 pounds of nitrate nitrogen per acre were being lost
annually to the water table. Though the losses were small from ir-
rigated fields compared to those from feedlots, they contributed much
more total nitrate because acreages were much more extensive.
Management to Minimize Nitrogen Losses
In summary, it is evident that leaching of nitrates below the
rooting zone of plants can and does occur in soils, depending upon
nitrogen supplies present, and that it may be larger on sandy soils
under irrigation than on heavier textured soils during summer when
evapotranspiration is greater than precipitation. Under fallow or in
late fall and early spring when soils are not frozen, movement of
nitrates downward within the soil profile occurs and some may
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152 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
eventually reach underground water supplies. Erosion losses of
nitrogen are mostly associated with the selective removal of organic
nitrogen compounds in the erosion debris. Thus, to minimize losses
and moderate potential pollution, soil management should include
erosion control practices, soil nitrogen should be kept to a minimum
during the colder months of the year or in the absence of a crop, and
fertilizer nitrogen should be added in amounts which allow for, but
do not greatly exceed, the amounts needed for efficient crop produc-
tion. It may be necessary to again emphasize the value of split ap-
plications of nitrogen fertilizer for efficiency of utilization via the
irrigation waters, with starter and nitrogen side-dressing of corn and
summer top-dressing of meadow and turf—all good crop production
management recommendations. Late season or fall application of
nitrogen should be in the ammoniacal form where soils are subject
to leaching. Temperatures should be low enough that nitrification is
negligible.
Alexander (1965) noted that the optimum temperature for nitri-
fication falls between 30° and 35° C. There is no fixed minimum tem-
perature above freezing, but rates are low. However, nitrate will
continue to be formed throughout the autumn in small amounts and
may be lost by leaching in those situations where there is movement
of water through the profile. This nitrate may be utilized by soil
microorganisms if carbonaceous crop residues are incorporated in
the fall.
Chemical inhibitors to delay oxidation of ammonia to nitrates
and nitrites have been suggested (Black, 1968). Alexander (1965)
listed many inhibitors and summarized the literature on their use.
Turner and Goring (1966) examined a number of researchers on the
use of 2-chloro-6-(trichloro-methyl) pyridine, one of the more effective
inhibitors, and concluded that yield and nitrogen content of several
crops could be increased by the use of this inhibitor. In general, the
inhibitors appeared to be more effective at temperatures below 21° C
and much less effective at temperatures up to 32° C. Studies by
Janssen and Wiese (1969) in Nebraska and by Huber et al. (1969)
in Idaho support these conclusions. Further investigation is warrant-
ed to improve use reliability and for reduction in price.
Under irrigated soil conditions, or farming situations where
there is control over the water table, it may be possible to dissipate
some nitrate entering tile lines with controlled demtrification. Meek
et al. (1969), using simulated tile lines in soil columns, reduced
nitrates in the tile effluent to an average value of 0.5 ppm by sub-
merging the tile lines, thus creating an anaerobic environment.
The role of deep-rooted crops, like alfalfa, in a rotation and of
cover crops in the fall to remove nitrogen and enhance the organic
nitrogen reserve should not be minimized for selected locations.
Stewart et al. (1968) showed that little nitrate was present under
alfalfa fields and grasslands to depths of 20 feet. Where the water
table is within this depth, some nitrate may even be removed from
the water table.
Sod crops and crop residues left on soil surfaces during non-
cropping seasons can also reduce erosion as will minimum tillage.
The adoption of minimum tillage practices (Cook, 1962) would ap-
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CHAPTER 9 / FERTILIZER MANAGEMENT / 153
pear to be particularly warranted as a management tool for protec-
tion of the organic nitrogen pool against rapid oxidation and yield of
nitrates. This practice also protects against destruction of soil ag-
gregates, preserves structure, and decreases runoff (Burwell et al.,
1968). Infiltration is increased, which provides more water for use
by plants and a more extensive plant cover.
As noted in an earlier section, nitrogen is a key element in crop
production because of its transitory nature in soils, and it is becoming
more economical to add too much fertilizer nitrogen rather than to
risk not applying enough. It is evident now that in selected locations,
movement of surplus nitrates into water supplies can be serious, not
only as a potential pollutant but also as a loss to the efficiency of pro-
duction. University and commercial soil and plant tissue testing lab-
oratories and procedures are generally available for making fertilizer
recommendations, and these are geared for efficiency of production at
yield potential levels estimated to be feasible for a given soil and
climatic area. Nitrogen recommendations, particularly, are based on
the nitrogen requirement of the crop for maximum efficient produc-
tion (in the case of crops like sugar beets, potatoes, or malting barley
where surplus nitrogen reduces quality, it should be the "minimum"
requirement for maximum production of a product of acceptable
quality, as suggested by Stanford et al., 1965), efficiency of utilization
of nitrogen fertilizers used, and the nitrogen-supplying capability of
the soil via release of nitrogen from the organic nitrogen pool (Fenster
et al., 1969). As noted earlier, when irrigation waters from surface
wells containing nitrates are used, cropland management recom-
mendations can be developed to include the amounts of nitrogen
which will be supplied with the irrigation waters (Stout and Burau.
1967). Realistic recommendations can help avoid overapplication.
The environmental quality factor will have to be brought into the
formulation of responsible recommendations.
A number of researchers are attempting to determine what
constitutes an acceptable application rate for nitrogen that will both
sustain production and minimize pollution.
Webber (1967) in Ontario, Canada, has postulated an applica-
tion rate for farm manures which would not release on decomposi-
tion over 300 pounds per acre of ammonia-nitrogen which could be
oxidized to nitrate. This amount could presumably be utilized by corn
or by hay-pasture crops and removed with the crop or be dissipated
otherwise, such as by denitrification or tied up by microorganisms in
the decomposition of crop residue. At this level, it was suggested that
there would be little nitrate in surplus which would move into under-
ground water supplies. It was further suggested that for small grains,
or sandy soils under irrigation, a lower figure would have to be used.
The figure for "safe" application levels of nitrogen for different crop
management systems is currently being checked out, using 32-inch
diameter, 42-inch deep lysimeters on a Guelph loam.
In Missouri Smith (1968) suggested an application rate no higher
than is required for optimum yields, approximately 100 pounds of
nitrogen per acre, if nitrates are not to reach groundwater supplies.
As noted earlier, nitrate movement studies have been underway for 7
years on soils with widely different characteristics and where corn
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154 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
yields have varied from about 60 to more than 150 bushels per acre.
Nitrates accumulated progressively in 8-fcot profiles at all levels of
application above 100 pounds per acre annually.
Cooke (1969) suggests that use efficiency of nitrogen fertilizers
which currently average less than 50% must be increased in the
future not only for reduction in crop production costs but to avoid
loss of nitrogen by leaching. Promising researches relate to the con-
trol of ammonia oxidation and other reactions in soils as noted earlier
and perhaps also the decomposition of urea, higher analysis and more
readily available compounds of phosphorus reacted with ammonia,
pelleting of fertilizers to control solubility rates and with the seed for
immediate utilization, and "agronomic control" by plant analysis with
subsequent and immediate application of fertilizer if needed by aerial
topdressings or perhaps in the irrigation waters. Different soils, cli-
mates, and cropping systems would have to be given individual re-
search attention.
CONCLUSIONS
Nitrogen and phosphorus, as nutrient elements, are important
to both land and aquatic plants, and normally reach water supplies
via land runoff in the erosion debris which is selectively enriched in
organic nutrient materials or via the leachate which may contain
mobile nitrate ions.
Fertilizer usages in the midcontinent area are rapidly increasing
to maximize production and increase efficiency, and further increases
are anticipated. Current information suggests that phosphatic fer-
tilizers incorporated in the soil are not contaminating natural waters,
but nitrogen fertilizers may be contributory in selected situations.
For example, where application rates, together with soil supplies,
have exceeded crop needs and/or excessive leaching occurs induced
by over-irrigation of sandy soils, nitrates can be contributed to under-
ground water supplies.
Fertilizer phosphorus quickly converts to unavailable forms in
mineral soils and the evidence indicates that one of the ways of re-
ducing the level of soluble phosphorus in water would be to effect soil
contact such as by filtration through the soil medium. Some phos-
phorus is removed from frozen plant materials with snow melt waters
which is difficult to control except perhaps by diversion terraces into
seepage areas.
Nitrogen fertilizer application rates should approximate crop
needs, which for a given soil type and climatic zone are based on pro-
duction potential estimates for the crops to be grown. One hundred
pounds of nitrogen per acre can apparently be safely applied to
cropped soils without major contribution of nitrate to the leachate,
and up to 300 pounds per acre in some instances, though much more
research is needed in this area.
Management recommendations refined through the years for
maximizing production are not incompatible with the objective of
reducing nutrient contamination of natural waters. These involve
an emphasis on erosion control measures to include vegetative cover
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CHAPTER 9 / FERTILIZER MANAGEMENT / 155
which, in addition to a reduction in runoff and erosion, removes fer-
tilizer nutrients with the harvest and effects water transpiration to
reduce leaching. Other factors include the use of cover crops where
adapted and incorporation of crop residues in the fall for protection
of soil surfaces and utilization of plant nutrients, minimum tillage to
improve structure and reduce the mineralization of organic nitrogen
reserves, and an emphasis on increasing fertilizer use efficiencies by
the crop, such as by split applications and the use of ammoniacal
forms of nitrogen in the fall.
Further research is needed on nutrient balances and reactions
in soils to maintain supplies at levels needed for crop production; to
increase the efficiency of use as a percentage of that supplied, cur-
rently less than 50% ; and to minimize loss of nitrate to water sup-
plies. This would include research on nitrification-inhibiting chemi-
cals so as to retain nitrogen in the ammoniacal form, pelleting, or
other to reduce solubility or application with the seed to increase up-
take, and plant analysis monitoring of nutrients with needed applica-
tions applied quickly, perhaps by air or in the irrigation waters.
Water quality standards as established by the federal and state
water pollution control groups should be compatible with the need for
maintaining adequate nutrients for efficient crop production con-
sistent with management programs designed to minimize losses to
adjacent water supplies.
REFERENCES
Alexander, M. 1965. Nitrification. In Soil nitrogen, ed. W. V.
Bartholomew and F. E. Clark, pp. 307-43. Madison, Wis.: Am.
Soc. Agron.
Allison, F. E. 1955. The enigma of soil nitrogen balance sheets.
Advan. Agron. 7:213-50.
. 1965. Evaluation of incoming and outgoing processes that
affect soil nitrogen. In Soil nitrogen, ed. W. V. Bartholomew
and F. E. Clark, pp. 573-606. Madison, Wis.: Am. Soc. Agron.
Allison, F. E., Roller, E. M., and Adams, J. E. 1959. Soil fertility
studies in lysimeters containing lake land sand. USDA Tech.
Bull. 1199.
Bailey, G. W. March 1968. Role of soils and sediment in ivater pol-
lution control. I. Reactions of nitrogenous and phosphatic com-
pounds with soils and geologic strata. Fed. Water Pollution
Control Adm., Southeast Water Lab. Bull., U.S. Dept. Interior.
Ballantyne, C. R., Schaller, F. W., and Phillips, J. A. Dec. 1967.
Erosion control factors and universal soil loss equation. Iowa
State Univ. Coop. Ext. Serv. Bull, p. 410.
Barrows, H. L., and Kilmer, V. J. 1963. Plant nutrient losses from
soils by water erosion. Advan. Agron. 15:303—16.
Beaton, J. D., and Tisdale, S. L. 1969. Potential plant nutrient con-
sumption in North America. Sulphur Inst. Tech. Bull. 16.
Bedell, G. D., Kohnke, H., and Hickok, R. B. 1946. The effects of
two farming sytems on erosion from cropland. Soil Sci. Soc.
Am. Proc. 11:522-26.
Biggar, J. W., and Corey, R. B. 1968. Nitrate and phosphate in lakes
and streams. Unpublished mimeo., Univ. of Wis., Madison.
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156 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Bizzel, J. A. 1944. Lysimeter experiments. VI. The effects of crop-
ping and fertilization on the losses of nitrogen from the soil.
Cornell Agr. Exp. Sta. Memo. 256, pp. 1-14.
Black, C. A. 1968. Soil-plant relationships. 2nd ed. New York:
John Wiley.
Blake, G. R., Allred, E. R., Van Bavel, C. H. M., and Whisler, F. D.
196C. Agricultural drought and moisture excesses in Minnesota.
Minn. Agr. Exp. Sta. Tech. Bull. 235, pp. 1-36.
Burwell, R. E., Sloneker, L. L., and Nelson, W. W. 1968. Tillage
influences water intake. J. Soil Water Conserv. 23:185-87.
Cook, R. L. 1962. Soil management for conservation and production.
New York: John Wiley.
Cooke, G. W. 1969. Fertilizers in 2000 A.D. Intern. Superphosphate
and Compound Manufacturers' Assoc., Bull. 53, pp. 1-13.
Corey, R. B., Hasler, A. D., Lee, G. F., Schraufnagel, F. H., and
Wirth, T. L. Jan. 1967. Excessive water fertilization. Report
to the Water Subcommittee, Natl. Resources Com. of State
Agencies, Wis.
Duley, F. L., and Miller, M. F. 1923. Erosion and surface runoff
under different soil conditions. Mo. Agr. Exp. Sta. Bull. 63.
Fenster, W. E., Overdahl, C. J., and Grava, J. 1969. Guide to com-
puter programmed soil test recommendations in Minnesota.
Minn. Agr. Ext. Serv. Spec. Rept. 1.
Gardner, W. R. 1965. Movement of nitrogen in soil. In Soil nitro-
gen, ed. W. V. Bartholomew and F. E. Clark, pp. 555—72. Madi-
son, Wis.: Am. Soc. Agron.
Carman, W. H. 1969. Nitrogen facts and fallacies. Plant Food Rev.
15:15-20.
Haas, H. J., Grunes, D. L., and Reichman, G. A. 1961. Phosphorus
changes in Great Plains soils as influenced by cropping and
manure applications. Soil Sci. Soc. Am. Proc. 25:214—18.
Hanson, L. D., and Fenster, W. E. Oct. 1969. Phosphorus and lake
quality. Crops Soils.
Hargett, N. L. 1969. 1968 fertilizer summary data Natl. Fertilizer
Develop. Center, TVA, Muscle Shoals, Ala.
Hauser, V. L. 1968. Nitrates in playas. Agr. Res. Notes 17:15.
Hays, O. E., Bay, C. E., and Hull, H. H. 1948. Increased production
on a loess-derived soil. Am. Soc. Agron. }. 40:1061-69.
Hemwall, J. B. 1957. The fixation of phosphorus by soils. Advan.
Agron. 9:95-113.
Holt, F. G. 1969. Runoff and sediment as nutrient sources. Water
Resources Res. Center Bull. 13, pp. 35-38, Univ. of Minn.
Holt, R. F., Timmons, D. R., and Latterell, J. J. 1969. Accumulation
of phosphates in water. In press. /. Food Agr. Chem.
Huber, D. M., Murray, G. A., and Crane, J. M. 1969. Inhibition of
nitrification—a deterrent to nitrate nitrogen loss and potential
water pollution. Soil Sci. Soc. Am. Proc. In press.
Janssen, K. A., and Wiese, R. A. 1969. The influence of 2-chloro-6-
(Trichloromethyl) pyridine with anhydrous ammonia on corn
yield, N-uptake, and conversion of ammonium to nitrate. M.S.
thesis, Univ. of Nebr., Lincoln.
Johnston, W. R., Ittihadieh, F., Damn, R. M., and Pillsbury, A. F.
1965. Nitrogen and phosphorus in tile drain effluent. Soil Sci.
Soc. Am. Proc. 29:287-89.
Keeney, D. R., Konrad, J. G., and Chesters, G. 1969. Nitrogen distri-
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CHAPTER 9 / FERTILIZER MANAGEMENT / 157
bution in some Wisconsin lake sediments. J. Water Pollution
Control Federation. In press.
Kilmer, V. J., Hays, O. E., and Muckenhirn, R. J. 1944. Plant
nutrient and water losses from Fayette silt loam as measured
by monolith lysimeters. Am. Soc. Agron. J. 36:249-63.
Latterell, J. H., Holt, R. F., and Timmons, D. R. 1969. Phosphate
availability in lake sediments. Personal communications; manu-
script in press.
MacGregor, J. M., Hanson, L. D., and Ellis, J. E. 1969. Unpublished
research and personal communication. Univ. of Minn., St. Paul.
Maderak, M. L. 1963. Quality of waters, Minnesota—a compilation,
1955-62. Minn. State Dept. Conserv. Bull. 21.
. 1965. Chemical quality of ground ivater in Minneapolis-St.
Paul area of Minnesota. Minn. State Dept. Conserv. Bull. 23.
Martin, W. P. 1969. Controlling nutrients and organic toxicants in
runoff. Water pollution by nutrients—sources, effects and con-
trol. Water Resources Res. Center Bull. 13, pp. 39-48. Univ.
of Minn.
Massey, H. F., and Jackson, M. L. 1952. Selective erosion of soil
fertility constituents. Soil Sci. Soc. Am. Proc. 16:353-56.
Meek, B. D., Grass, L. B., Willardson, L. S., and MacKenzie, A. J. Aug.
18-22, 1969. Nitrate transformation in a column with a con-
trolled water table. Abstr. Western Soc. Soil Sci., Wash. State
Univ., Pullman.
Megard, R. O. 1969. Diagnosing pollution in Lake Minnetonka.
Water pollution by nutrients—sources, effects and control.
Water Resources Res. Center Bull. 13, Univ. of Minn.
Miller, M. F., and Krusekoff, H. H. 1932. The influence of sys-
tems of cropping and methods of culture on surface runoff and
soil erosion. Mo. Agri. Exp. Sta. Res. Bull. 177.
Pearson, R. W., Jordan, H. V., Bennett, O. L., Scarsbrook, C. E..
Adams, W. E., and White, A. W. 1961. Residual effects of
fall- and spring-applied nitrogen fertilizers on crop yields in the
southeastern United States. USDA Bull. 1254, pp. 1-19.
Rogers, H. T. 1942. Losses of surface-applied phosphate and lime-
stone through runoff from pasture land. Soil Sci. Soc. Am. Proc.
7:69-76.
Russell, E. W. 1961. Soil conditions and plant growth. 9th ed. New
York: John Wiley.
Schmidt, E. L. 1956. Soil nitrification and nitrates in waters. Minn.
Public Health Dept. Repts. 7:497-503.
Smith, D. D., and Wischmeier, W. H. 1962. Rainfall erosion.
Advan. Agron. 14:109-48.
Smith, G. E. 1965. Water forum: nitrate problems in water as re-
lated to soils, plants and ivater. Mo. Agr. Exp. Sta. Spec. Rept.
55:42-52.
. 1967. Fertilizer nutrients as contaminants in water supplies.
Am. Assoc. Adv. Sci. Publ. 85, pp. 173-86.
-. April 9, 1968. In Water pollution as related to agriculture.
pp. 13-27. Joint seminar, Univ. of Mo. and Mo. Water Pollu-
tion Board, Columbia.
Soileau, J. M. 1969. Effects of fertilizers on ivater quality—a collec-
tion of abstracts and references. Natl. Fertilizer Dev. Center,
TVA, Muscle Shoals, Ala.
Stallings, J. H. 1957. Soil conservation. New York: Prentice-Hall.
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158 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
Stanford, G., Ayres, A. S., and Doi, M. 1965. Mineralizable soil
nitrogen in relation to fertilizer need of surgarcane in Hawaii.
SoilSci. 99:132-37.
Stewart, B. A., Viets, F. G., and Hutchinson, G. L. 1968. Agricul-
ture's effect on nitrate pollution of groundwater. /. Soil Water
Conserv. 23:13-15.
Stout, P. R., and Burau, R. G. 1967. The extent and significance of
fertilizer buildup in soils as revealed by vertical distribution of
nitrogenous matter between soils and underlying ivater reser-
voirs. Am. Assoc. Adv. Sci. Publ. 85, pp. 283-310.
Taylor, A. W. 1967. Phosphorus and water pollution. /. Soil Water
Conserv 22'228—31.
Timmons, D. R., Burwell, R. E., and Holt, R. F. 1968. Loss of crop
nutrients through runoff. Minn. Sci. 24:16-19.
Turner, G. O., and Goring, C. A. I. 1966. N-serve, a status report.
Down Earth 22:19-25.
Wadleigh, C. H. 1968. Agriculture and the quality of our environ-
ment. USDA Misc. Publ. 1065.
. Feb. 4, 1968. Nitrate in soil, water and food. Commentator
response to article, "Pollution hazard may curb fertilizer use,"
appearing in Des Moines (Iowa) Sunday Register.
Wagner, G. H., and Smith, G. E. 1960. Recovery of fertilizer nitro-
gen from soils. Mo. Agr. Exp. Sta. Res. Bull. 738.
Webber, L. R. 1967. The nature of problem: soil pollution. Ontario
Pollution Control Conf., Toronto, Can.
. 1969a. Characteristics of soil percolates folloiving applica-
tion of liquid manure. 1968 Progress Rept., Dept. of Soil Sci.,
Univ. of Guelph, Ontario, Can.
1969b. Animal waste utilization using undisturbed soil
lysimeters. Unpublished data and personal communication.
Univ. of Guelph, Ontario, Can.
Webber, L. R., and Elrick, D. E. 1966. Research needs for control-
ling soil pollution. Agr. Sci. Rev. 4:10-20.
White, W. C. 1965. Plant nutrient toll 1965. Plant Food Rev.
11 (4): 17-18.
White, R. E., and Beckett, P. H. T. 1964. Studies on the phosphate
potentials of soils. Plant Soil 20:1.
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CHAPTER TEN
WORKSHOP SESSION
J. T. PESEK, Leader
R. A. OLSON, Reporter
D,
R. PESEK opened the session by summarizing its objectives
as being a forum for questioning the speakers in the formal program,
a second channel for bringing into focus the lacking data which
should be filled in by future research, and a means for all interested
individuals to make statements and discuss any aspect of the role of
fertilizers as water pollutants.
A lively session among the 40 to 50 participants resulted for
the prescribed period. Procedure followed was to read prepared
statements which had been submitted, followed by discussion from
the floor.
The initial statement by Dr. L. B. Baldwin of the University of
Florida Extension Service concerned Lake Okeechobee and the St.
John's River Basin Water Development Projects which constitute
closed water systems. Herewith, an attempt is being made to mea-
sure water nutrient levels from the eutrophication standpoint which,
it is hoped, will provide information of countrywide interest. Most
relevant aspects of Dr. Baldwin's statement were as follows:
Florida has several important agricultural areas adjacent to large lakes
and reservoirs which are a part of well-developed and closely regulated
water management projects. In the case of Lake Okeechobee (740 sq.
miles) and the peat soil farming area (1,100 sq. miles) around its
southern perimeter, water is pumped to the lake during wet periods,
and taken from the lake for irrigation. The lake itself is contained
by levees, and is regulated seasonally for stage control. During periods
of below normal rainfall, discharge may not be necessary, and the lake
and agricultural area function as a closed system. This situation may
contribute substantially to nutrient buildup in the lake.
A 2-year study of the nutrient condition in Lake Okeechobee was
started in January 1969. It is the purpose of the study to determine
the level of nutrients in the lake and in all water entering the lake.
This, and subsequent studies, may show that eutrophication of the
lake, under present or proposed future stages, will be accelerated by
J. T. PESEK is Professor and Head, Department of Agronomy, Iowa
State University. R. A. OLSON is Professor, Department of Agronomy,
University of Nebraska.
159
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160 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
nutrients from agricultural lands. All aspects of this situation involve
important segments of Florida's economy.
A similar study is underway in the St. John's River Basin, which
is also part of a controlled system. These studies should produce data
of interest and use to other areas of the country. Subsequent studies
of fertilizer-soil-water management and water system management
should also be of importance.
Discussion on this topic centered particularly around source of
phosphorus that might be responsible for its buildup in lake and
stream waters in an area such as Okeechobee which is surrounded
by peat and muck soils. Dr. Black expressed belief from the phos-
phorus chemistry standpoint that any phosphorus that did accumu-
late in this situation would not be from mineralization of the peat
and muck but rather would come from other sources.
Dr. George Smith noted the occurrence of the substantial phos-
phate deposits a short distance to the north in Florida and questioned
the relevance of phosphate rock origin to current considerations in
the St. John's-Okeechobee projects. Environmental conditions were
entirely different, however, and presumably there would be no corol-
lary between the two.
The next statement was by Dr. Robert D. Harter of the Univer-
sity of New Hampshire who wrote concerning the perplexing nature
of phosphorus in surface water and its role in eutrophication. The
relevant portion of his statement was as follows :
Even in highly eutrophic lakes, the amount of phosphorus in solution
is small; much less, in fact, than is needed for plant growth. Yet,
luxurious algal blooms are common. Where, then, do they obtain the
needed phosporus?
Studies of the phosphorus cycle in lakes are being conducted, and
nutrient budgets of lakes are being worked out. An increasing amount
of this type of study is needed. However, the contribution of the lake
sediment has frequently been ignored in these deliberations. Lake
sediment has been shown to have a large adsorption capacity for
phosphorus. Further research is needed on the fate of phosphorus
which is unaccounted for in nutrient budgets, and is assumed to be
adsorbed by the sediment.
Soil scientists have for years attempted to identify the phosphorus com-
pounds in soil. Long-term fertility plots have been shown to contain
increased amounts of hydroxyapatite, variscite, and other highly in-
soluble phosphorus compounds. However, there is little information
on the length of time needed for formation o£ the most insoluble crys-
tals and the kinetics of formation. Before the eutrophication process
can be completely understood and any measure of control or reversal
initiated, we need to know whether the same insoluble phosphorus
compounds are formed in lake sediment. If they are not, we need to
know why. If they are, we need to work out the kinetics of formation,
with an eye to increasing the rate of phosphorus fixation in highly
insoluble forms.
Discussion following this statement centered on equilibria
established between the solid/liquid phase, the time required for
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CHAPTER 10 / WORKSHOP SESSION / 161
equilibria to be reached, the turnover time involved with algal uptake,
the role of carbon dioxide on algal uptake at low concentrations, and
water stratification implications on equilibria.
A significant observation in this respect is the lack of algal
problems with high sediment levels in the water. This is responsible
for the fact that the high stem dams of the Missouri River and else-
where are now creating taste and odor problems in municipal water
supply systems in their vicinities which did not exist before impound-
ment and sedimentation occurred. Also relevant is water depth, evi-
denced by the lack of stratification in the shallow eastern part of
Lake Okeechobee compared with considerable stratification in the
deeper western part of the lake and a much greater eutrophication
of the former. Lake depth also influences the problem of bottom
rooted plants, complimented by water clarity.
There was agreement that studies are needed to establish the
fate of phosphorus in lake sediments, including the kinetics of for-
mation of insoluble phosphorus compounds. Although some work
was recognized as being underway in Wisconsin, Oregon, and else-
where, much more is needed in various sections of the country with
a variety of soil sediments, kinds of clay minerals, and environmental
conditions, especially temperature. A number of questions were
raised without specific answers, to wit: (1) When and where should
sampling be done of stream and lake waters for expressing nutrient
concentrations—that is, a need exists for sampling standards.
(2) How do we best measure phosphorus in stream or lake sediments,
by water extraction? (3) Do bottom rooted plants serve as a phos-
phorus pump from these sediments, exuding phosphorus to algae in
the upper waters?
The next statement by Dr. J. Lunin of ARS-SWC accepted that
phosphorus movement into lakes and streams is simplified by reason
of the adsorbed state of the element on sediments. Movement of
nitrates, however, is a much more difficult problem. The most perti-
nent aspects of his statement follow:
A nitrogen balance would be highly desirable to determine. But how
do we quantify deep percolation and denitrification losses? We can
study nitrogen transformation processes in the laboratory and green-
house, with lysimeters, and on field plots. Indeed, we are studying
only segments of a problem. To truly evaluate the contribution of
nitrogen fertilization to the nitrate content of a stream, lake, or
groundwater source, we must integrate multiple effects found within
the watershed supplying that water resource. It is obvious that we
must take into consideration all the hydrologic parameters of that
watershed because nitrates move with water.
The question is, How can we evaluate agriculture's contribution
to the nitrate content of a given water resource? Let us define the
research required to develop and implement a workable water quality
model for a watershed that would integrate all climatic, agronomic,
animal, etc., effects within that watershed.
Discussion here recognized that nitrate buildup is usually noted
whenever streams are running high with runoff. A key question
raised was, How often do geologic sources of nitrate influence re-
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162 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
ported stream values, especially with the high runoff conditions?
There was group concurrence that a great deal of deep profile in-
vestigation is needed for tracing the course of nitrate from the top-
soil to the groundwater. North Dakota, for example, commonly
finds a pool of nitrate at the 2-foot depth, more or less. There may
well be similar accumulation zones at considerable depths in other
regions that are of rather ancient origin.
The statement of Dr. James P. Law, Jr., Research Soil Scientist
of the FWPCA, made particular reference to nitrate buildup in
irrigated areas.
The switch to high-value crops, increased fertilization rates, and in-
creased irrigation contributes to increased rates of water quality deg-
radation, especially where shallow groundwater exists as the only
dependable supply for rural domestic, municipal, and livestock require-
ments. These facts suggest the need for serious scrutiny of present
fertilizer application methods and rates.
The time-worn practice of applying fertilizer for entire crop needs as
one or two slug-feedings during the growing season could very well be
shown to be both wasteful and impractical. In tile-drained areas it
has, in fact, been shown that large percentages of the fertilizer nutri-
ents applied are lost from cropland in the drainage water. Other
studies have shown increased crop yields by adding fertilizer require-
ments in small increments throughout the growing season—for exam-
ple, irrigating grain crops with sewage effluents containing limited
quantities of nutrients (Ref: A. D. Day and co-workers in Arizona).
Fertilizer elements in excess of immediate crop needs are subject to
loss by leaching below the root zone and eventual occurrence as pol-
lutants in water supplies, both surface and groundwater.
The following are suggested as areas worthy of research, with the ob-
jectives of correcting some of the present pollution problems relative
to fertilizer application methods and rates:
I. Subsurface irrigation lends itself to automation and much more
efficient water use, which can be beneficial in controlling leaching
losses of fertilizer elements. The control of surface evaporation
in subsurface systems also alleviates the salinity problem associ-
ated with irrigation return flow.
2. Spoon-feeding fertilizer elements in small increments throughout
the growing season would greatly lessen the possibility of wasteful
losses of fertilizer to surface and groundwater supplies. Economic
benefits of fertilizer applications would be increased. Soluble
fertilizer fed directly in the irrigation water is an example. The
closely controlled application of subsurface systems would be a
beneficial method.
3. Further studies into application of slew-release fertilizers by con-
ventional methods are suggested. The objectives should be to maxi-
mize fertilizer benefits and minimize environmental pollution.
4. Control of excess plant nutrien's arising from fertilizer application
depends on a better understanding of the movement and ultimate
fate of these materials. Studies aimed at clarification of nutrient
transport and deposition mechanisms may furnish new leads to
better control.
Discussion following Dr. Law's paper was concerned especially
with determining what is economic rate of fertilizer application with-
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CHAPTER 10 / WORKSHOP SESSION / 163
out building excess residual in the soil. It is common opinion that
some nominal excess in application rate, as in the order of 50%,
is necessary, due to portions of the soil root zone being dry during
parts of the season. The pertinent question then is just how much
nutrient exists residually in the entire rooting profile at the begin-
ning of the crop season for determining what would be the economic
rate of application.
A primary question from this area is, How do we go about
measuring fertilizer influence on groundwater? Some of the barom-
eter watersheds as in Oregon and the Treynor watershed in Iowa
may be revealing in the near future.
The statement of Dr. Ronald G. Menzel of ARS-USDA was
similar to that posed by Dr. Lunin, as follows:
Nitrate concentrations in groundwater or surface water mean very
little by themselves. One must understand the dynamics of each
situation. Where is the nitrate coming from? Where is it going? How
rapidly? Only by answering these questions can we relate fertilizer
practices to water contamination. Therefore, it appears that measure-
ments of groundwater movement, chemical and biological transforma-
tions of nitrogen, and gaseous losses of nitrogen are critically needed.
One major problem is interrelating the different measurements involv-
ing nitrogen transformations and movement. Those measurements
that have to be made in the laboratory must somehow be extrapolated
to field conditions. For example, it may be necessary to estimate deni-
trification losses in the field from laboratory measurements. Can these
be made more realistic by increasing sample size, controlling com-
position of the gaseous and aqueous phases, increasing static pressure,
or by other means? At the same time, we need to attempt direct
measurements of denirrification in the field. Possibly an indicator re-
action, similar to the reduction of acetylene as an indicator of nitrogen
fixation, can be found for denitrification. If so, the difficulty of dis-
tinguishing denitrified nitrogen from atmospheric nitrogen might be
avoided.
Discussion in this case brought out that there has been an in-
crease of about 15% in recent years of water supplies in Iowa with
greater than 45 ppm nitrate. An interesting proposal for the immedi-
ate locality was one that would take all of the wastewater from the
city of Ames, Iowa, which now goes into water courses and tise it year
around for irrigating some 1,000 acres of land in the immediate
vicinity. Thereby, stream pollution would be alleviated at the same
time that many of the fertility requirements of a substantial area of
land were taken care of.
Further discussion centered around ways of removing nitrate
that has accumulated in a soil zone before it reaches the underlying
groundwater. One under investigation is the addition of an energy
source to an anaerobic zone where nitrate has accumulated to pro-
mote denitrification.
A statement by Dr. T. R. Smith of the FWPCA supplied data on
nitrate and tile drains in streams of Illinois as follows :
Water discharged from tile drains in prairie soils in Vermilion County,
Illinois, was studied in the spring of 1968.
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164 / PART 2 / PLANT NUTRIENTS AS WATER POLLUTANTS
In the Middle Fork Vermilion River Basin, two tile drains averaged
13.5 and 17.3 mg/1 nitrate nitrogen and at the same time the river
averaged 9.1 mg/1. At baseflow and with no tile discharge, the river
contained 0.24 mg/1 nitrate nitrogen. The North Fork Vermilion
River Basin yielded similar data.
The data indicate that most of the nitrate was coming from agricul-
tural land and that it was a widespread condition, otherwise, the river
would have had a much lower nitrate concentration during spring
runoff.
Nitrate losses in these concentrations pose the possibility of polluting
reservoirs and groundwater supplies.
It appears that research may be needed on this matter to determine
whether nitrates could be used more efficiently, with less being lost in
drainage water and at the same time maintain high crop yields.
This problem could occur anywhere in the humid prairie region.
Complementary to this statement was a report from Story
County, Iowa, of 5 to 40 ppm nitrate nitrogen in tile drains. It was
further contended that nitrate has been increasing steadily in rivers
of Illinois in the last 10 to 20 years, much more rapidly during the
last 5 years, and especially in the most productive agricultural areas
of the state. These increases coincide closely with the pyramidal
growth in fertilizer nitrogen consumption during the interval in-
volved.
Acknowledged was the need to study again the amount of nitro-
gen received in precipitation under modern conditions. Results
could be quite different from those obtained early in the century.
From these discussions the following summary statements and
questions evolved:
1. Recognizing that phosphorus accumulates in water largely
through sediments, how do we go about reducing the phosphorus
level maintained in the equilibrium solution?
2. We do not know with certainty the source of nitrogen in waters.
A good deal of research is needed for locating the source and
means of abatement.
3. What quality of water should the public have reasonable right
to expect, keeping in mind the services demanded and the quality
levels attainable in relation to economic considerations?
4. It would be most helpful if agronomists, engineers, and hydrolo-
gists would work together closely in solving the problems in-
volved.
5. It should be made clear that controls on the use of fertilizers
would necessitate some radical changes in our American eating
habits, to the very great dissatisfaction of many. Fertilizers have
done much toward making this the best fed nation on earth.
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PART THREE_
PESTICIDES AS WATER POLLUTANTS
-------
CHAPTER ELEVEN
CHEMISTRY AND METABOLISM
OF INSECTICIDES
PAUL A. DAHM
A
. s man embarked on global travel during the eighteenth and
nineteenth centuries, a number of events occurred that had immense
consequences in relation to pest control. The world was searched for
new plants to adorn the greenhouses that were part of every gentle-
man's residence. These plants brought new pests that flourished in
their new environments. Similarly, other pests were distributed by
shipments of infested food, grain, and other products. In fact, most
of today's major pest control problems exist because of man's igno-
rance and indiscretion. Attempts to control these problems led to the
development of chemical pesticides. Reviewing the history of some
of these early developments (Ordish, 1968) will prepare us to con-
sider a few examples of modern insecticides.
Until about 1840 most farmers regarded pests as something one
had to accept, as the will of God. By the late 1840s M. Grison of
Versailles discovered that lime-sulfur was a cure for powdery mildew,
Uncimda necator, a serious pest of grapes that came from America.
Soon after it was discovered that the disease could be arrested by
dusting plants with sulfur. This was the first large-scale successful
use of chemicals for pest control.
The next significant step occurred when pioneers introduced the
potato plant to beetles, Leptinotarsa decemlineata, feeding on wild
solanaceous plants growing on the eastern slopes of the Rocky
Mountains from Canada to Texas. This beetle, soon known as the
Colorado potato beetle, displayed a strong preference for its new
food, the potato. The beetle began spreading eastward at an average
rate of about 85 miles a year, often destroying entire potato crops
wherever it appeared. Virtually nothing checked the multiplication
and spread of the beetle until about 1865 when an arsenic-containing
PAUL A. DAHM is professor of Entomology, Department of Zoology
and Entomology, Iowa State University.
Journal Paper No. J-6509 of the Iowa Agriculture and Home Econom-
ics Experiment Station, Ames. Projects No. 1351, 1435, and 1686.
Preparation of this paper was supported by Public Health Service Re-
search Grant ES-00205 from the Division of Environmental Health
Sciences and North Central Regional Project NC-85.
167
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168 / PART 3 / PESTICIDES AS WATER POLLUTANTS
chemical known as Paris green was used as a spray on potato plants
to kill the beetles. Although Paris green was quite toxic and likely
to injure plant foliage, it remained the leading stomach poison for
insect control until the introduction of lead arsenate in 1892.
A combination of copper sulfate and lime, subsequently called
Bordeaux mixture, was discovered by accident in the 1880s to be an
effective fungicide for the control of downy mildew, Plasmopara viti-
cola.
Chemical control of pests was well launched by these discoveries
during the latter part of the nineteenth century. At the Columbian
Exposition in Chicago in 1893 there were some 42 patented insecti-
cides offered by several manufacturers.
Until 1940 insecticides consisted mostly of arsenicals, fluosili-
cates, plant-derived chemicals, various petroleum products, synthetic
thiocyanates, and several fumigant chemicals. Discovery of the
broad-spectrum insecticidal properties of p,p'-DDT and y-HCCH (lin-
dane) in the 1940s stimulated a pesticide bonanza. The millenium,
however, had not arrived. When populations of both harmful and
useful insects were drastically reduced by these modern chemicals,
nontarget arthropods occasionally became pests because their preda-
tors were no longer plentiful enough to reduce their populations. In-
secticide-resistant strains of more than 200 species of arthropod pests
also developed, owing to chemical selectivity of the new insecticides.
Although benefits from modern pesticides are manifold, their use has
been progressively questioned, especially since publication of Silent
Spring by Rachael Carson (1962). We are now at a stage at which
people from several disciplines and with different expertise are look-
ing critically at many facets of pesticide use. Also, a variety of pest-
control methods are being examined with the hope of reducing some
of the problems caused by chemical agents.
In 1966 over half of all U.S. farmers used weed-, insect-, or
disease-control chemicals on their crops. In this same year about
29% of the farmers used insecticides on one or more crops. But only
5% of the crop, pasture, and range acres, or about 12% of the crop
acres excluding pasture and rangeland. were treated for insect
control (Fox et al., 1968). An estimate of the use of insecticides in
the 48 contiguous states in the early 1960s showed that less than 5%
of the acreage had insecticides applied; about 0.4% of the total
area generally considered favorable to wildlife had insecticides ap-
plied; and 85% of the acreage planted by U.S. farmers to crops each
year was not treated with insecticides (Hall, 1962). In actual quan-
tities, about 156 million pounds of insecticide products were used on
farms in the 48 contiguous states in 1964. This amounts to
about 70 pounds for each commercial farmer in the United States.
Of the total, about 143 million pounds were used on crops (including
crops, pasture, rangeland, and land in summer fallow) and 13 million
pounds for other purposes (principally livestock and livestock build-
ings). Although alternative methods of controlling insect pests are
being developed and employed, it has been estimated that conven-
tional insecticides are still needed to control 80 to 90% of insect
problems affecting agriculture (Knipling, 1969).
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CHAPTER 11 / CHEMISTRY AND METABOLISM OF INSECTICIDES / lev
The abundance and mobility of water and its solvent properties
nave resulted in a variety of relationships between water and insec-
ticides. Fundamentally, water can transport insecticides, and insec-
ticides can pollute water. Many insecticides are applied to plants
or soil for protection or beautification. Such applications are made
to fields, lawns, orchards, forests, gardens, greenhouses, nurseries,
and shrubs. Although soil is the principal recipient of insecticidal
chemicals, water is their principal distributor after application.
Insecticides may pollute water when they are applied to areas harbor-
ing insects and related arthropods and to domestic animals and their
wastes. Insecticidal pollution of water may also occur when man
accidentally or irresponsibly misuses these chemicals. Back-siphon-
ing of spray materials into wells when filling spray equipment, dam-
age to containers of insecticidal chemicals in transit, improper dis-
posal of insecticides in all forms, excessive applications, and various
misapplications are examples of these misuses. Occasionally, indus-
trial wastes containing insecticides may lead to water pollution. And
there is continuous cycling of small quantities of insecticides by vol-
atilization from the earth into the atmosphere and precipitation
back onto soil and water.
The three major classes of insecticides presently in use are chlo-
rinated hydrocarbons, organophosphates, and carbamates. Of the
eight insecticides used most in the United States in 1964, four were
chlorinated hydrocarbons (DDT, DDD, aldrin, and toxaphene), three
Yv'ere organophosphates (methyl parathion, parathion, and mala-
fhion), and one was a carbamate (carbaryl) (Table 15, Eichers et al.,
1968). These will serve as examples around which to discuss the
metabolism of insecticides.
GDI AMD RELATED CHEMICALS
Both praising and damning declarations have been made about
DDT since its introduction as an insecticide in the 1940s. Campaigns
against this chemical have recently been waged so vigorously in
communication media and in legislative and judicial branches of
our government that there is considerable doubt that DDT will survive
is an insecticide. Mankind is giving a pragmatic twist to the future
use of DDT by applying the Socratean adage, 'To know is to suffer."
DDT has probably been studied more intensively and extensively
than any other synthetic chemical. It is one of the cheapest organic
pesticides. Its chemical stability and biological effects have been
praised or criticized, depending upon how one reacts to the need for
and presence of this chemical in the environment. The principal
metabolites of DDT are well known (Fig. 11.1). The best known
metabolic route involves dehydrochlorination of DDT to DDE, 1,1-
dichlorc-2,2-bis(p-chlorophenyl) ethylene, because this reaction is
the primary reason for resistance of insects to DDT (Sternburg et al.,
1953). Strains of insects resistant to DDT have a large proportion
of their population possessing an enzyme that can dehydrochlorinate
DDT to less-toxic DDE (Lipke and Kearns, 1960). Susceptible strains
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170 / PART 3 / PESTICIDES AS WATER POLLUTANTS
CHCOOH
Cl
Cl-/ "V") CHCC1
DDE
CHCHCI,
DICOFOL DDD
FIG. 11.1. The principal metabolites of DDT.
of insects have relatively few individuals with this biochemical pro-
ficiency; hence, they succumb to the insecticide. DDE is also the
most common metabolite of DDT found in avian tissues. It has be •:;;.•
suggested that DDE plays a major role in causing thinness of e,/-
shells in certain species of birds (Heath et al., 1969), possibly I-
inducing hepatic microsomal metabolism of steroids. One or n,<
earliest metabolic discoveries about DDT was its conversion to DD/';
bis(p-chlorophenyl) acetic acid, in mammals (White and Swe^ne;,
1945; Jensen et' al., 1957; Durham et al., 1963), including x:.i\.
(Neal et al., 1946; Durham et al., 1965). DDA is readily excreted h
the urine. Biological reductive dechlorination of DDF to
DDD(=TDE), l,l-dichloro-2,2-bis(p-chlorophenyl) ethane, has tu-K
proved comparatively recently (Finley and Pillmore, 1963; Bar!;;;
and Morrison, 1964; Walker et al., 1965). This reaction occurs ;!;•;.•
readily under anaerobic conditions in animal tissues and in n;i : v
organisms. It is now quite acceptable to report DDD as a i)H:.ah.a|;h
of DDT but for many years the possibility of this compound Leaig
formed biologically was scoffed at by some scientists. DDD is a com-
mercial insecticide in its own right. Replacement of hydrogen on u'.e
tertiary carbon of DDT by a hydroxyl group forms a metabolite of jovr
toxicity to insects and mammals but cf high toxicity to miles r^L
moto, .1959; Agosin et al., 1961). A commercial miticide called die-.';!-!
(Keltharie®, 4,4'-dJchloro-a-[trichloromethyl] benzhydrol) is id-'in '.(•:•.'
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CHAPTER 11 / CHEMISTRY AND METABOLISM OF INSECTICIDES / 171
TABLE 11.1 Toxicity of DDT and metabolites to adult male rats.
Chemical
DDT (technical) ....
DDA
DDE
Dicofol (=Kelthane®)
DDD (-TDE)
Acute Oral Toxicity LD.-/>
(mg/kg)
217
740
880
1,100
>4,000
Relative Toxicity
1 0
3.4
4 1
5.1
>18.0
Source: Gaines (1969).
to this metabolite. Another metabolite o£ DDT is DBF, p,p'-dichloro-
benzophenone (Menzel et al., 1961; Abou-Donia and Menzel, 1968);
this compound has frequently been reported in metabolism studies
with insects. Although several criteria should be used to compare the
toxicity of chemicals, the most complete comparison of the toxicity
of DDT with its principal metabolites can be made on the basis of
acute oral toxicity values (Table 11.1). The toxicity of the chemicals
in this table is inversely related to the numerical values.
Many metabolites of DDT other than the five already described
have been reported (Abou-Donia and Menzel, 1968). A recent dis-
covery about DDT metabolism is the in vivo isomerizations that lead
to the formation of p,p'-DDT from feeding o,p'-DDT to rats (Klein et
al., 1964) and the formation of o,p'-DDT and o,p'-DDD from feeding
p,p'-DDT and p,p'-DDD to young chickens (Abou-Donia and Menzel,
1968). The approximately 20% of o,p'-DDT in technical DDT is con-
verted to p,p'-DDT and then to p,p'-DDE in living avian tissue; in the
anaerobic conditions after death, o,p'-DDT is metabolized to o,p'-DDD
(French and Jefferies, 1969). The absence of o,p'-DDT and metab-
olites in field specimens is ascribed to the rapid rate of breakdown
and a masking of the o,p'-DDD residue during analysis by the relative-
ly large amounts of p,p'-DDE. These examples illustrate the com-
plexity of metabolism studies and the pitfalls of interpreting analyt-
ical data.
The exact biochemical cause of the toxicity of DDT and related
chemicals to certain organisms has never been proved. Several
theories on how DDT acts have been promulgated. An extensive study
of feeding DDT in the diet of rats suggested that the effects of DDT
depend not only on DDT but also on some unidentified secondary fac-
tor (Ortega et al., 1956). An example of this hypothesis is the sug-
gestion that DDE is the major factor in toxicity of DDT and that the
amount of DDE produced from DDT determines the level of toxicity
of DDT in different species (Bailey et al., 1969). An earlier study,
however, suggested that residues of DDE were not critical in birds
that died from DDT (Stickel et al., 1966). These examples are cited
to illustrate the confusion about the toxicity of DDT, its metabolites,
and related compounds. The estrogenic activity of o.n'-DDT (Bitman
et al., 1968) and the conversion of analogues of DDT to estrogenic
metabolites (Welch et al., 1969) are interesting new developments
that may link DDT metabolism studies with the claim that this in-
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172 / PART 3 / PESTICIDES AS WATER POLLUTANTS
sccticide is the indirect cause of a reduction of eggshell thickness
associated with failing reproduction and population decline of cer-
tain predatory birds (Stickel, 1968; Porter and Wiemeyer, 1969). In
the past, surveys have not usually distinguished between the presence
of p.p'- and o,p'-DDT. A change in analytical procedures could clarify
how widespread the latter isomer really is.
Although the use of DDT as an insecticide is declining, the en-
vironment will continue to be monitored for this chemical and its
metabolites. A review of the voluminous data on DDT, its analogues,
and its metabolites in the environment is beyond the scope of this
presentation. I predict, however, that interpreting these data
in terms of biological effect or no-effect will provide a continuing de-
bate for many years. Methoxychlor, 2,2-bis(p-methoxyphenyl)-l,l,l-
trichloroethane, is an insecticidal analogue of DDT that has much
lower mammalian toxicity than DDT. For example, the acute oral
LD-0 of methoxychlor to rats seems to be scmewhere between 5 to 7
g/kg (Smith et al., 1946; Hodge et al., 1950). This insecticide shows
little tendency to be stored in the body fat and other lipids. If there is
a general ban on the use of DDT, methoxychlor may serve as a re-
placement for DDT in a few pest control situations, but the organo-
phosphate and carbamate insecticides currently available will prob-
ably fill most of the gaps left by withdrawing DDT from pest control
use.
ALDRIN AND DIELDRIN
Aldrin is one of a group of chlorinated hydrocarbon insecticides
that also includes dieldrin, endrin, and heptachlor. Interrelationships
of structure and activity are known for about 500 of these so-called
cyclodiene compounds (Soloway, 1965). The following comments
draw upon recent reviews of the metabolism of these insecticides
(Brooks* 1966, 1968, 1969; Korte, 1968). The 1969 review by Brooks
is especially comprehensive in its treatment of the subject. Biological
epoxidation of aldrin (Fig. 11.2), isodrin, and heptachlor produces
dieldrin, endrin, and heptachlor epoxide, respectively. The epoxida-
tion of these insecticides is interesting because the metabolites.
dieldrin, endrin, and heptachlor epcxide, are about as toxic as, and
more persistent than, their parent compounds (Gaines, 1960, 1969).
Cl PI
Cl
FIG.
DIELDRIN
11.2. Epoxidation of aldrin to dieldrin.
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CHAPTER II / CHEMISTRY AND METABOLISM OF INSECTICIDES / 173
Many efforts have been directed toward finding metabolic
products of dieldrin, endrin, and heptachlor epoxide (and other mem-
bers of this group of insecticides). Until recently these epoxides were
considered stable in metabolizing systems. It was sometimes thought
that the insecticides were stored in fat, as the epoxides in those in-
stances in which epoxidation could occur, and ultimately excreted in-
tact in the feces. It is now known that these compounds are amenable
to further metabolism, including hydroxylation, hydrolytic (or oxida-
tive) elimination of chlorine atoms (when present) other than those
of the intact hexachloronorbornene nucleus, and hydrolysis of epoxide
rings. In vivo studies with rats have shown that aldrin is converted
to polar metabolites from either dieldrin formed from aldrin or
dieldrin administered separately (Datta et al., 1965; Korte, 1968).
Metabolites of dieldrin have been found also in urine from man
(Cueto and Hayes, 1962) and rabbits (Korte, 1968). A more recent
study revealed two metabolites from rats fed a diet containing 100
ppm of dieldrin (Richardson et al., 1968). The mixed-function oxi-
dases that metabolize so many foreign substances are also involved in
cyclodiene metabolism in insects and mammals in vitro. The nature
of the metabolites so far isolated, the parallel between microsomal
enzyme induction and increased metabolism in vivo observed for
some mammals, and the action of synergists in insects provide a link
between the in-vivo and in-vitro processes.
The toxicology and no-effect levels of aldrin and dieldrin have
been extensively reviewed by a panel selected by the the Secretary of
Health, Education, and Welfare from nominations by the National
Academy of Sciences (Hodge et al., 1967). The following statements
are from the summary of this review. The acute oral toxicity for
either aldrin or dieldrin ranged from 20 to 70 mg/kg among 12
species of animals; the estimated lethal dose for man is approxi-
mately 5 g. The mortality among several species of animals, after
either repeated short-term or chronic doses, ranged from 0.5 to 300
ppm. No body weight changes occurred among several species of
animals at 2 ppm or less in the diet. Pathological conditions were ob-
servable at levels in the diet ranging from 0.5 to 10 npm among
several species of animals. And, typical diets in Eneland and in the
United States are estimated to contain 1 to 2 ppb of dieldrin; dieldrin
concentrations in human fat probably average about 0.2 ppm.
Insecticides of the cyclodiene group have had low residue toler-
ances imposed upon them from the beginnings of their use. Further
residue tolerance restrictions have been placed on these chemicals in
recent years. Environmental persistence and unfavorable biological
effects of some of the cyclodiene insecticides and development of re-
sistance to these insecticides by some species of insects and other
arthropods suggest that the use of these insecticides will decline.
TOXAPHENE
An anomalous situation exists with respect to our knowledge of
toxaphene, an insecticide used more extensively in the United States
-------
174 / PART 3 / PESTICIDES AS WATER POLLUTANTS
in 1964 than any other insecticide (Eichers et al., 1968). The exten-
sive use of toxaphene, since it became available for commercial use
about 1947 (Parker and Beacher, 1947), has not been accompanied
with published information about its composition and metabolism.
Toxaphene is a chlorinated camphene having an approximate empiri-
cal formula of C]0H]0C1S; it contains 67 to 69% chlorine. Toxaphene
is a general convulsant that acts on the central nervous system. In
this respect it is similar to DDT and the cyclodiene insecticides. In
contrast to them, however, little is known about the metabolism of
toxaphene. It is probably slowly detoxified in the liver'. This assump-
tion is based on its close chemical relationship to camphor, which is
detoxified in the liver, and the isolation of ethereal sulfate and glu-
curonic acid conjugates of toxaphene in the urine (Conley, 1952).
Although toxaphene is a highly chlorinated organic compound,
and hence readily detected by electron-capture gas chromatography
(GLC), there is a paucity of residue and metabolism data that distin-
guish between components of the technical product. Residues of
toxaphene cannot be determined quantitatively in environmental
samples by GLC because toxaphene is a mixture of compounds that
gives a continuum of curves with a wide spread of retention times.
This results in mutual interference from many common pesticides.
This difficulty is illustrated in Figure 11.3 by GLC curves of toxa-
phene, DDT, and a combination of the two insecticides (Benevue
and Beckman, 1966). These GLC curves are especially pertinent be-
cause one of the major markets for toxaphene has been a 2:1 com-
binat'on of toxaphene and DDT as an insecticide for use on cotton.
The difficulties of estimating the components of toxaphene are
illustrated in studies of the persistence of toxaphene in lakes in
which it has been used as a substitute for rotenone to reduce rough
fish populations (Johnson et al., 1966; Terriere et al., 1966). Various
formulations of toxaphene showed slightly different gas chromato-
grams, the components of toxaphene seemed to be degraded at dif-
ferent rates, and the components had different toxicities for fish
(Johnson et al., 1966). It is clear that until the chemistry and me-
tabolism of toxaphene are better known, the fate of this insecticide
in natural waters will be poorly understood.
FIG. 11.3. GLC curves of
toxaphene, DDT, and a
combination of the two in-
secticides. (Benevue and
Beckman, 1966.)
TOXAPHENE + DDT
SOLVENT
RESPONSE
TOXAPHENE
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CHAPTER 11 / CHEMISTRY AND METABOLISM OF INSECTICIDES / 175
ORGANOPHOSPHATE
0
(R0)2 POX
INHIBITION
REACTION
• CHOLINE
ACETYLCHOLINESTERASE
ACETYLCHOLINE
HOH
L. ACETIC
ACID
L
NERVE SYNAPSE
FIG. 11.4. The principal toxic action of organophosphate insecticides.
PARATHION AND MALATHION
Parathion, methyl parathion, and malathion are members of
a large class of organophosphate insecticides. "Organophosphate"
is often employed as a generic term to cover all the toxic organic
compounds containing phosphorus. Organophosphates are more
specifically designated as phosphates, phosphoiiates, phosphorothio-
nates, phosphorothiolates, phosphorodithioates, phosphoramidates,
etc., depending upon the atoms attached to the phosphorus; for ex-
amples, see O'Brien (1960). There is an extensive literature on these
compounds, including books concerned exclusively with organophos-
phates (O'Brien, I960; Heath, 1961).
The most important reaction of Organophosphates is with acetyl-
cholinesterase, an enzyme involved in the transmission of nerve im-
pulses (Fig. 11.4). Acetylcholine. a chemical mediator of nerve im-
pulses at synapses, is normally hydrolyzed very quickly by acetyl-
cholinesterase. Any disruption of this reaction causes acetylcholine
to accumulate. Acetylcholine is itself a moderately toxic chemical. It
acts as a poison and causes well-known symptoms of poisoning. Or-
ganophosphates with a P-_=:0 structure irreversibly react with cholin-
esterases, preventing these enzymes from accomplishing their hydro-
lytic function.
Parathion was introduced about 1944 in Germany. As recently
as 1964, methyl parathion (the dimethyl analogue of parathion) and
parathion were the most widely used Organophosphates in the United
States (Eichers et al., 1968). Although methyl parathion and para-
thion are chemically very similar, each seems needed to control dif-
ferent species of pest insects; therefore, both exist on the commercial
market. Both are quite toxic chemicals; for example, their acute oral
LD-o values with male rats are 14 and 13 mg/kg for methyl parathion
and parathion, respectively (Gaines, 1969). Because their properties
and metabolism are so nearly alike, further attention will be given
only to parathion.
The toxicity of parathion develops from a desulfuration reaction
-------
176 / PART 3 / PESTICIDES AS WATER POLLUTANTS
PARATHION
HYDROLYSIS
(C2H50)2 P-0
REDUCT(ON
TO-NH2
;DESULFURATION
S 0
(CH30)2 P-S - CMC*
DEMETHYLATION
°C2H5
CH
,OC2H
2"
-HYDROLYSIS
0
HYDROLYSIS
FIG. 11.5. Some points of metabolic attack on parathion and mala-
thion.
that changes P=S to P—O (Fig. 11.5). This converts parathion to
paraoxon, a compound with strong cholinesterase-inhibiting proper-
ties. This important intoxication reaction occurs with all organo-
phosphates having a P=S structure and is especially catalyzed by
liver microsomal enzymes. These enzymes require reduced nicotina-
mide adenine dinucleotide and oxygen with in vitro reactions. Two
primary degradation reactions of parathion and paraoxon are shown
in Figure 11.5. One of these is a hydrolytic reaction that yields di-
ethylthiophosphoric acid and p-nitrophenol. This reaction is catalyzed
by liver microsomal oxidases similar, if not identical, to those that ef-
fect conversion of parathion to paraoxon (Nakatsugawa et al., 1969).
The p-nitrophenol from parathion degradation appears in urine and
provides a sensitive indicator of exposure to parathion before any sig-
nificant decline in cholinesterase activity can be detected (Davies et
al., 1966). The second degradation reaction illustrated for parathion
in Figure 11.5 involves reduction of the p-nitro group of parathion
and paraoxon to form aminoparathion and aminoparaoxon, re-
spectively. This reaction occurs under a variety of conditions
(O'Brien, I960; Lykken and Casida, 1969; Mick and Dahm, 1970).
The metabolism of parathion has been investigated with several
species of animals, plants, and microorganisms (O'Brien, I960; El-
Refai and Hopkins, 1966). Other reported metabolites of parathion
and paraoxon include desethyl parathion, desethyl paraoxon, diethyl
phosphoric acid, ethyl phosphoric acid, and phosphoric acid. All
metabolites of parathion, except paraoxon, are less toxic than the
parent insecticide.
Malathion was accepted for commercial use as an insecticide in
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CHAPTER 11 / CHEMISTRY AND METABOLISM OF INSECTICIDES / 177
1952. Since then, it has been used to control many species of insects
and other arthropods. It is a major insecticide used throughout the
world, owing partly to its low toxicity to mammals. For example, its
acute oral LD-0 in adult male rats is 1,375 mg/kg (Gaines, 1969).
The major intoxication route for malathion is desulfuration to mala-
oxon (Fig. 11.5) and inhibition of acetylcholinesterase by the mala-
oxon produced (O'Brien, 1960). It is the detoxication reactions that
set malathion apart and are responsible for its remarkably low toxicity
to mammals. The most important reactions involve the hydrolysis
by carboxylesterase of one of the two available carboxylic ethyl esters
of malathion and malaoxon as shown in Figure 11.5 (Dauterman and
Main, 1966). Malathion monoacid, the major metabolite of mala-
thion, has been identified as O,O-dimethyl-S-(l-carboxy-2-carbethoxy)
ethyl phosphorodithioate (Chen et al., 1969). Other detoxication re-
actions shown in Figure 11.5 produce hydrolytic products, such as
malathion diacid, malaoxon mono- and diacids, O.O-dimethyl phos-
phorodithioate, O,O-dimethyl phosphorothioate, dimethyl phosphate,
monomethyl phosphate, and phosphoric acid (O'Brien, 1967).
Malathion gained further prominence when Frawley et al.
(1957) showed that simultaneous administrations of malathion and
EPN, O-ethyl O-p-nitrophenyl phenylphosphonothioate, to dogs and
rats caused strong synergistic effects in the form of cholinesterase
inhibition. Several later studies showed that EPN inhibits the car-
boxylesterase that hydrolyzes malathion and malaoxon. A number
of other combinations of organophosphates also have been synergistic
(O'Brien, 1967). Fears that ingestion of mixtures of low levels of
organophosphates, and possibly other chemicals, as residues on foods
might produce overt symptoms of cholinesterase depression have so
far proved false.
Malathion is comparatively more toxic to insects than to mam-
mals, seemingly because of less effective hydrolytic detoxication by
carboxylesterases in insects. EPN fails to synergize the toxicity of
malathion to insects, and certain strains of insects resistant to mal-
athion have a high carboxylesterase level (O'Brien, 1967).
The metabolism of organophosphate insecticides has received
special attention in recent reviews by Fukuto and Metcalf (1969) and
Lykken and Casida (1969). From these and other sources it can be
concluded that organophosphate insecticides include chemicals that
range from high toxicity (e.g., parathion) to low toxicity (e.g., mala-
thion). These insecticide molecules usually possess several places
that are vulnerable to metabolic attack, and the metabolic products
are more water soluble than the parent insecticides. Organophos-
phates are physically and chemically less stable than organochlorine
insecticides (e.g., DDT and dieldrin) and therefore present less of a
hazard for environmental contamination than organochlorines.
CARBARYL
Carbaryl (—Sevin®) is the most widely used insecticide belong-
ing to a group of esters of N-methyl and N-dimethyl carbamic acid.
The carbamate insecticides show somewhat erratic patterns of selec-
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3
178 / PART 3 / PESTICIDES AS WATER POLLUTANTS
CARBARYL
FIG. 11.6. Some points of HYDROLYSIS -, ^ HYDROXYLAT.ON
metabolic attack on car- -, 0-CNHCH
baryl. EPOXIDATION
AND
HYDROLYSIS
HYDROXYLATION
tive toxicity to insects. These insecticides are fairly potent inhibitors
of cholinesterases, and the symptoms resulting from this action are
typically cholinergic. The inhibitory action of carbamates, however,
is reversible, in contrast to the action of organophosphates.
Carbaryl quite readily undergoes several metabolic reactions
(Fig. 11.6), including hydroxylation attack on the N-methyl group and
two locations on the napthol ring and epoxidation followed by epoxide
cleavage and hydrolysis on the nonphenolic ring. Each of these initial
oxidation products subsequently conjugates and is excreted as a sul-
fate or glucuronide in mammals, but may persist as a glycoside in
plants. Hydrolysis of the carbamyl ester linkage releases 1-napthol,
which is rapidly metabolized. Additional information about the
metabolism of carbaryl and other carbamate insecticides is included
in reviews by Fukuto and Metcalf (1969) and Lykken and Casida
(1969). Carbamates are currently viewed as competitors of organo-
phosphates for pest-control purposes.
SUMMARY
Insecticides occur in the environment because of purposive ap-
plications for pest control and because of accidents and carelessness.
The major problems with insecticides arise from the contamination of
the environment and food and the development of resistant arthro-
pod-pest populations. The persistence of insecticides in the atmos-
phere, water, soil, plants, animals, and microorganisms is being inves-
tigated. Alterations of insecticides occur under both metabolic and
nonmetabolic conditions.
Knowledge of the metabolism of insecticides is prerequisite to
their development and use for insect control. Identification and toxi-
cological assessment of metabolic products should precede establish-
ment of residue and other safety factors. More basically, metabolism
studies of insecticides reveal intoxication and detoxication processes
and how these relate to physiological effects and problems of re-
sistance. Some of the ways that organic insecticides are metabolized
in living organisms are hydrolysis, hydroxylation, dehalogenation,
dehydrohalogenation, desulfuration (z^cxidation), O-dealkylation, N-
dealkylation, reduction, and conjugation. Metabolic attack occurs at
one or more sites on an insecticide molecule. Plants and animals
often metabolize insecticides by similar pathways. With some insecti-
cides, primary metabolic attack may form compounds whose toxicity
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CHAPTER 11 / CHEMISTRY AND METABOLISM OF INSECTICIDES / 179
approximately equals or is greater than the parent insecticide (e.g.,
aldrin^dieldrin; parathion^paraoxon). Further metabolism pro-
duces compounds of much lower toxicity. Other insecticides are de-
toxified directly (e.g., DDT-^DDE, although DDE may have subtle
physiological effects on nontarget organisms). The metabolism of an
insecticide from administration to target sites and in and out of
storage tissues generally produces compounds of greater water solu-
bility to facilitate excretion of metabolites. Because the persistence of
some of our present organochlorine insecticides (e.g., DDT, DDD,
cyclodienes) creates environmental problems, future insecticide de-
velopments will probably give special attention to effective chemicals
that degrade to compounds with negligible environmental effects.
Although this review is primarily concerned with metabolism,
numerous nonmetabolic factors exert effects on the structure and per-
sistence of insecticides. Some of these nonmetabolic factors include
light, water, heat, acidity and alkalinity, atmospheric constituents,
metal ions, and soils. An indication of the nonmetabolic complexities
of the decomposition of insecticides is given in a review by Crosby
(1969). Furthermore, the solubilities of insecticides in soil and water
are especially important in relation to their movement and persistence
in the environment. An exhaustive search of the literature by Gun-
ther et al. (1968), however, revealed only Limited useful data on water
solubility.
REFERENCES
Abou-Donia. M. B., and Menzel. D. B. 1968. The metabolism in vivo
of l,l,l-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT), 1,1-
dichloro-2,2-bis(p-chlorophenyl) ethane (DDD) and 1,1-dichlo-
ro-2,2-bis(p-chlorophenyl) ethylene (DDE) in the chick by em-
bryonic injection and dietary ingestion. Biochem. Pharmacol.
17:2143-61.
Agosin, M., Michaeli, D., Miskus, R., Nagasawa, S., and Hoskins,
W. M. 1961. A new DDT-metabolizing enzyme in the German
cockroach. /. Econ. Entomol. 54:340—42.
Bailey, S., Bunyan, P. J., Rennison, B. D., and Taylor, A. 1969. The
metabolism of l,l-di(p-chlorophenyl)-2,2-dichloroethylene and
l,l-di(p-chlorophenyl)-2-chloroethylene in the pigeon. Toxicol.
Appl. Pharmacol. 14:23-32.
Barker, P. S., and Morrison, F. O. 1964. Breakdown of DDT in
mouse tissue. Can. J. Zoo/. 42:324-25.
Benevue, A., and Beckman, H. 1966. The examination of toxaphene
by gas chromatography. Bull. Exptl. Contamination Toxicol.
1:1-5.
Bitman, J., Cecil, H. C., Harris, S. J., and Fries, G. F. 1968. Estro-
genic activity of o,p'-DDT in the mammalian uterus and avian
oviduct. Science 162:371-72.
Brooks, G. T. 1966. Progress in metabolic studies of the cyclodiene
insecticides and its relevance to structure-activity correlations.
Wor/d Rev. Pest Control 5:62-84.
. 1968. Perspectives of cyclodiene metabolism. Symposium
on the Science and Technology of Residual Insecticides in Food
-------
180 / PART 3 / PESTICIDES AS WATER POLLUTANTS
Production with Special Reference to Aldrin and Dieldrin. Spon-
sored by Shell Chemical Co.
-. 1969. The metabolism of diene-organochlorine (cyclodiene)
insecticides. Residue Rev. 27:81-138.
Carson, R. L. 1962. Silent spring. Boston: Houghton Mifflin.
Chen, P. R., Tucker, W. P., and Dauterman, W. C. 1969. Structure
of biologically produced malathion monoacid. J. Agr. Food
Chem. 17:86-90.
Conley, B. E. 1952. Pharmacologic properties of toxaphene, a chlo-
rinated hydrocarbon insecticide. J. Am. Med. Assoc. 149:1135-
37.
Crosby, D. G. 1969. The nonmetabolic decomposition of pesticides.
Ann. N.Y. Acad. Sci. 160:82-96.
Cueto, C., Jr., and Hayes, W. J., Jr. 1962. The detection of dieldrin
metabolites in human urine. /. Agr. Food Chem. 10:366—69.
Datta, P. R., Laug, E. P., Watts, J. O., Klein, A. K., and Nelson, M. J.
1965. Metabolites in urine of rats on diets containing aldrin or
dieldrin. Nature 208:289-90.
Dauterman, W. C., and Main, A. R. 1966. Relationship between
acute toxicity and in vitro inhibition and hydrolysis of a series
of carbalkoxy homologs of malathion. Toxicol. Appl. Pharma-
col. 9:408-18.
Davies, J. E., Davis, J. H., Frazier, D. E., Mann, J. B., and Welke,
J. O. 1966. Urinary p-nitrophenol concentrations in acute and
chronic parathion exposures. Advan. Chem. Ser. 60:67—78.
Durham, W. F., Ortega, P., and Hayes, W. J., Jr. 1963. The effect of
various dietary levels of DDT on liver function, cell morphology,
and DDT storage in the rhesus monkey. Arch. Intern. Pharma-
codijn. 141 (1-2): 111-29.
Durham, W. F., Armstrong, J. F., and Quimby, G. E. 1965. DDA
excretion levels. Arch. Environ. Health 11:76—79.
Eichers, T., Andrilenas, P., Jenkins, R., and Fox, A. 1968. Quanti-
ties of pesticides used by farmers in 1964. USDA, Agr. Econ.
Rept. 131.
El-Refai, A., and Hopkins, T. L. 1966. Parathion absorption, trans-
location, and conversion to paraoxon in bean plants. J. Agr.
Food Chem. 14:588-92.
Finlev. R. B., Jr., and Pillmore, R. E. 1963. Conversion of DDT to
DDD in animal tissue. BioScience 13:41-42.
Fox, A., Eichers. T.. Andrilenas, P., Jenkins, R., and Blake, H. 1968.
Extent of farm pesticide use on crops in 1966. USDA, Agr.
Econ. Rept. 147.
Frawley, J. P., Fuyat, H. N., Hagan, E. C., Blake, J. R., and Fitzhugh,
O. G. 1957. Marked potentiation in mammalian toxicity from
simultaneous administration of two anticholinesterase com-
pounds. J. Pharmacol. Exptl. Therap. 121:96-106.
French, M. C., and Jefferies, D. J. 1969. Degradation and disappear-
ance of ortho, para isomer of of technical DDT in living and
dead avian tissues. Science 165:914—16.
Fukuto, T. R., and Metcalf, R. L. 1969. Metabolism of insecticides
in plants and animals. Ann. N.Y. Acad. Sci. 160:97-111.
Gaines, T. B. 1960. The acute toxicity of pesticides to rats. Toxicol.
Appl Pharmacol. 2:88-99.
. 1969. Acute toxicity of pesticides. Toxicol Appl Pharmacol
14:515-34.
Gunther, F. A., Westlake, W. E., and Jaglan, P. S. 1968. Reported
-------
CHAPTER 11 / CHEMISTRY AND METABOLISM OF INSECTICIDES / 181
solubilities of 738 pesticide chemicals in water. Residue Rev.
20:1-148.
Hall, D. G. 1962. Use of insecticides in the United States. Bull.
Entomol. Soc. Am. 8:90-92.
Heath, D. F. 1961. Organophosphorus poisons. New York: Macmil-
lan (Pergamon).
Heath, R. G., Spann, J. W., and Kreitzer, J. F. 1969. Marked DDE
impairment of mallard reproduction in controlled studies. Na-
ture 224:47-48.
Hodge, H. C., Maynard, E. A., Thomas, J. F., Blanchet, H. J., Jr.,
Wilt, W. G., Jr., and Mason K. E. 1950. Short-term oral toxicity
tests of methoxychlor (2,2 di-(p-methoxy phenyl)-l,l,l-trichlor-
ethane) in rats and dogs. J. Pharmacol. Exptl. Therap. 99:140-
48.
Hodge, H. C., Boyce, A. M., Deichmann, W. B., and Kraybill, H. F.
1967. Toxicology and no-effect levels of aldrin and dieldrin.
Toxicol. Appl. Pharmacol. 10:613-75.
Jensen, J. A., Cueto, C., Dale, W. E., Rothe, C. F., Pearce, G. W., and
Mattson, A. M. 1957. DDT metabolites in feces and bile of rats.
J. Agr. Food Chem. 5:919-25.
Johnson, W. D., Lee, G. F., and Spyridakis, D. 1966. Persistence of
toxaphene in treated lakes. Intern. J. Air Water Pollution 10:
555-60.
Klein, A. K., Laug, E. P., Datta, P. R., Watts, J. O., and Chen, J. T.
1964. Metabolites: reductive dechlorination of DDT and DDD
and isomeric transformation of o,p'-DDT to p,p'-DDT in vivo.
J. Assoc. Official Agr. Chemists 47:1129-45.
Knipling, E. F. 1969. Alternative methods of controlling insect
pests. Food Drug Admin. Papers 3 (1): 16-24.
Korte, F. 1968. Metabolism of aldrin, dieldrin, and endrin. Sympo-
sium on the Science and Technology of Residual Insecticides in
Food Production *vith Special Reference to Aldrin and Dieldrin.
Sponsored by Shell Chemical Co.
Lipke, H., and Kearns, C. W. 1960. DDT-dehydrochlorinase. Advan.
Pest Control Res. 3:253-87.
Lykken, L., and Casida, J. E. 1969. Metabolism of organic insecti-
cide chemicals. Can. Med. Assoc. /. 100:145-54.
Menzel, D. B., Smith, S. M., Miskus, R., and Hoskins, W. M. 1961.
The metabolism of C14-labeled DDT in the larvae, pupae, and
adults of Drosophila melanogaster. J. Econ. Entomol. 54:9—12.
Mick, D. L., and Dahm, P. A. 1970. Metabolism of parathion by
two species of Rhizobium. J. Econ. Entomol. In press.
Nakatsugawa, T., Tolman, N. M., and Dahm, P. A. 1969. Degrada-
tion of parathion in the rat. Biochem. Pharmacol. 18:1103—14.
Neal, P. A., Sweeney, T. R., Spicer, S. S., and von Oettingen, W. F.
1946. The excretion of DDT (2,2-bis-(p-chlorophenyl)-l,l,l-
trichloroethane) in man, together with clinical observations.
Public Health Rept. 61:403-9.
O'Brien, R. D. 1960. Toxic phosphorus esters. New York: Academic
Press.
. 1967. Insecticides. Action and metabolism. New York:
Academic Press.
Ordish, G. 1968. 150 years of crop pest control. World Rev. Pest
Control 7:204-13.
Ortega, P., Hayes, W. J., Jr., Durham, W. F.. and Mattson, A. 1956.
DDT in the diet of the rat. Public Health Monograph 43.
-------
182 / PART 3 / PESTICIDES AS WATER POLLUTANTS
Parker, W. L., and Beacher, J. H. 1947. Toxaphene, a chlorinated
hydrocarbon with insecticidal properties. Univ. of Del. Bull.
264, Tech. 36. Newark, Del.
Porter, R. D., and Wiemeyer, S. N. 1969. Dieldrin and DDT: Effects
on sparrow hawk eggshells and reproduction. Science
165:199-200.
Richardson, A., Baldwin, M., and Robinson, J. 1968. Identification
of metabolites of dieldrin (HEOD) in the faeces and urine of
rats. /. Sci. Food Agr. 19:524-29.
Smith, M. L, Bauer, H., Stohlman, E. F., and Lillie, R. D. 1946. The
pharmacologic action of certain analogues and derivatives of
DDT. /. Pharmacol. Exptl. Therap. 88:359-65.
Soloway, S. B. 1965. Correlation between biological activity and
molecular structure of the cyclodiene insecticides. Advan.
Pest Control Res. 6:85-126.
Sternburg, J., Vinson, E. B., and Kearns, C. W. 1953. Enzymatic
dehydrochlorination of DDT by resistant flies. /. Econ. Entomol.
46:513-15.
Stickel, L. F. 1968. Organochlorine pesticides in the environment.
Bur. of Sport Fisheries and Wildlife, Spec. Scientific Rept.,
Wildlife No. 119, Wash., D.C.
Stickel, L. F., Stickel, W. H., and Christensen, R. 1966. Residues of
DDT in brains and bodies of birds that died on dosage and in
survivors. Science 151:1549-51.
Terriere, L. C., Kugemagi, U., Gerlach, A. R., and Borovicka, R. L.
1966. The persistence of toxaphene in lake water and its up-
take by aquatic plants and animals. /. Agr. Food Chem.
14:66-69.
Tsukamoto, M. 1959. Metabolic fate of DDT in Drosophila melano-
gaster. I. Identification of a non-DDE metabolite. Botyu-Ka-
gaku 24:141-51.
Walker, K. C., George, D. A., and Maitlen, J. C. 1965. Residues of
DDT in fattu tissues of big game animals in the states of Idaho
and Washington in 1962. USD A, ARS 33-105.
Welch, R. M., Levin, W., and Conney, A. H. 1969. Estrogenic action
of DDT and its analogs. Toxicol. Appl. Pharmacol. 14:358-67.
White, W. C., and Sweeney, T. R. 1945. The metabolism of 2.2-bis-
(p-chlorophenyl)l,l,l-trichloroethane (DDT). I. A metabolite
from rabbit urine, di(p-chlorophenyl) acetic acid; its isolation,
identification, and synthesis. Public. Health Rept. 60:66-71.
-------
CHAPTER TWELVE.
THE PESTICIDE BURDEN
IN WATER AND ITS
SIGNIFICANCE
H. PAGE NICHOLSON
ONTAMINATION of the environment by pesticides has been a
subject cf mounting concern for over 20 years. Within the past year
(1969) we have seen this concern, largely focused on DDT, reach a
pitch where an aroused public is demanding action. This is indicated
by the frequency and nature of coverage in the nation's press, the
appointment of committees at the highest levels of government to
consider the problem, and the number of restrictive bills prepared for
presentation to various state legislatures and to the Congress. Ari-
zona, in January 1969, banned the use of DDT for agricultural and
commercial purposes for a 1-year trial period. Michigan has restrict-
ed its employment to control of mice and bats and for emergency
public health purposes on approval of application. Steps have been
taken in a number of other states to reduce or better control the use
of DDT.
We in this country are not alone in our anxiety. Sweden has
placed DDT under a 2-year ban. The Soviet Union is considering such
a ban. Hungary has banned all organochlorine insecticides, and
Britain is reportedly phasing them out.1 All of this comes at a time
when world food production is at an all-time high and vector-borne
diseases of man and animals are more nearly arrested than ever be-
fore—a condition that must in part be credited to the effectiveness of
DDT and other pesticides.
DEFINITION OF THE PROBLEM
Pesticide Production and Usage
It is necessary to consider the amount and nature of pesticide
manufacture and usage to gain perspective about the potential for
H. PAGE NICHOLSON is Chief, Agricultural and Industrial Water Pol-
lution Control Research Program, Southeast Water Lab., FWPCA,
USDI, Athens, Georgia.
1. Chattanooga ("Tennessee) Times, June 11, 1969.
183
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184 / PART 3 / PESTICIDES AS WATER POLLUTANTS
pesticide involvement in water pollution. Although the United States
production of pesticides exceeded one billion pounds in 1967, not all
was used domestically; about 40% was exported and an additional 12
million pounds, primarily herbicides, were imported (Mahan et al.,
1968). It is not known how many of the 750 basic pesticidal chemi-
cals listed by Gunther et al. (1968) were included in these production
figures. Some idea can be obtained, however, from knowledge that
less than half this number were registered for use and covered by
legal tolerances or exemptions in the United States in 1966 (Westlake
and Gunther, 1966). Only 14 insecticides, 8 fungicides, and 5 herbi-
cides accounted for nearly 54% of the tonnage manufactured in the
United States in 1967 (Mahan et al., 1968).
From these data it may be concluded, at least with respect to the
quantities of pesticides used within the United States, that the po-
tential for widespread water pollution is currently limited to a rela-
tively few compounds. These figures, however, do not preclude the
possibility of local pollution problems associated with the manufac-
ture or processing of any pesticide, nor from accidental spills or care-
less use.
Environmental Contamination and Significance
The acute effects of gross pesticide pollution are well known and
depend upon the toxicity of the compound in question and its con-
centration in the environment. Widespread and chronic environ-
mental pollution problems involve only those pesticides and degrada-
tion products that are not only toxic but also possess the characteristic
of extended persistence sufficient to allow their escape from control
after application, coupled with the ability to be taken up and con-
centrated in living organisms. The latter has been called "biological
magnification." The pesticides most frequently involved are the
organochlorine insecticides DDT, TDE, endrin, heptachlor, aldrin,
dieldrin, chlordane, toxaphene, Strobane, and BHC or its gamma
isomer, lindane (Nichloson, 1969). More recently, the organic mer-
cury compounds have been implicated (Smart, 1968; Novick, 1969).
Among these compounds, DDT has been the most objectionable.
The universal occurrence of traces of DDT is now common knowl-
edge. It is used throughout much of the world and its secondary dis-
persion is aided by wind, water, and the movement of animals in
which residues have accumulated.
We are faced with mounting evidence that traces of DDT are not
as innocuous as many have believed. Transovarially conveyed DDT
was shown to be responsible for significant losses of lake trout
fry in a New York fish hatchery (Burdick et al., 1964), and investiga-
tions are being made to determine if losses of coho salmon fry in
Michigan hatcheries are similarly caused.
A drastic decline in populations of fish-eating raptorial birds,
such as the bald eagle and osprey, has long been associated circum-
stant;ally with the advent and use of DDT. Only recently has sup-
porting evidence been produced to suggest that DDT and its me-
tabolite, DDE, can cause an imbalance in calcium metabolism re-
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CHAPTER 12 / PESTICIDE BURDEN AND SIGNIFICANCE / 185
suiting in eggshell thinness and loss of eggs in the nest through break-
age (Hickey and Anderson, 1968). The hypothesis that sublethal
amounts of persistent chlorinated hydrocarbon pesticides are involved
is further strengthened by experimental studies with dieldrin and
DDT, using captive sparrow hawks (Porter and Wiemeyer, 1969).
Finally, we have experienced recently (March 1969) the seizure
by the Food and Drug Administration of 28,000 pounds of coho salm-
on, caught commercially from Michigan streams, because the fish
contained up to 19 ppm of DDT, an amount deemed to be excessively
high (Congressional Record, 1969). This seizure was a severe blow
to commercial fishing and recreational interests of the states adjacent
to Lake Michigan as this new fishery was proving to be an economic
bonanza (Henkin, 1969).
It should be pointed out that in each of these instances of in-
secticide-related loss, the insecticide must first have entered water.
Concentrations in Water
A synoptic survey for chlorinated hydrocarbon insecticides in
waters of 56 of the nation's major drainage basins and 3 of the Great
Lakes was made by the U.S. Public Health Service on whole-water
samples collected during the period September 18-29, 1964 (Weaver
et al., 1965). The samples from 96 sites in 41 states were analyzed
by thin layer chromatography and microcoulometric titrarion gas
chromatography. The wide distribution of dieldrin, endrin, and DDT,
with its metabolite DDE, is significant (Table 12.1). Concentration
values in water all were less than one ppb.
TABLE 12.1. Chlorinated hydrocarbon insecticides and related compounds
in major rivers of the United States.
Compound
Dieldrin
Endrin
DDT
DDE
TDE
Aldrin
Heptachlor
Heptachlor epoxide
BHC
Geographic
Distribution
(No. states with
positive or
presumptively
positive samples)
36
28
28
28
1
10
16
0
2
No
Rivers
and
Lakes
Positive
39
23
22
17
1
1
0
0
0
No.
Hfi
30
23
18
1
1
0
0
0
Positive
Positive
and Quantified
Range ppb*
O.OG2->0.118
0.003->0.094
0.007-0.087
0.002-0.018
0.083
0.085
Trace
Source: Adapted from data by Weaver et al. (1965).
Note: Except Alaska and Hawaii.
* Minimum detectable concentrations of dieldrin, endrin, DDT, DDE, al-
drin, and heptachlor ranged from 0.002 to 0.010 ppb. Comparable values
for TDE, heptachlor epoxide, and BHC were 0.075, 0.075, and 0.025 ppb,
respectively.
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186 / PART 3 / PESTICIDES AS WATER POLLUTANTS
TABLE 12.2. Pesticides in ten selected western streams, 1965-66.
No. Samples Positive Range
Compound of 114 from 11 Stations of Concentration
Lindane
Dieldrin
Heptachlor epoxide . . .
DDE
DDT
Heptachlor
TDE
Endrin
Aldrin
2 4-D
2,4,5-T
Silvex
Total
46
29
20
18
14
14
13
7
4
0
0
0
... 75 positive for one
or more pesticides
(ppb)
0.005-0 020
0.005-0 015
0 005-0 090
0.005-0 020
0.025-0 110
0.005-0 015
0.005-0 015
0.010-0.040
0.005-0 015
0.005-0.110
Source: Adapted from data by Brown and Nishioka (1967).
Similarly, the U.S. Geological Survey, in October 1965, began the
collection and analysis of water samples with associated suspended
sediment from selected streams west of the Mississippi River (Brown
and Nishioka, 1967; Manigold and Schulze, 1969). The samples,
taken monthly, were examined by electron capture gas chroma-
tography for the common chlorinated hydrocarbon insecticides and
the herbicides 2,4-D, silvex, and 2,4,5-T. Results of the first year's
work on 10 rivers are summarized in Table 12.2, and those for the
subsequent 2 years from 19 rivers are given in Table 12.3.
All 12 pesticides or derivatives were recovered at one time or
another. Sixty-six percent of 114 water samples taken during the first
year were positive for 1 or more pesticides. Forty-nine percent of 333
TABLE 12.3. Pesticides in nineteen selected western streams, 1966-68.
No. Samples Positive Range
Compound of 333 from 20 Stations of Concentration
DDT
DDE
2 4-D
TDE
2 4 5-T
Heptachlor
Dieldrin
Silvex •
Lindane
Aldrin
Endrin
Heptachlor epoxide . . .
Total
, . . . 82
49
, . . . 41
35
28
27
24
14
13
11
4
2
. . . 164 positive for one
or more pesticides
(ppb)
0.01-0.12
0.01-0.06
0.01-0.35
0.01-0 04
0.01-0.07
0.01-0.04
0.01-0.07
0.01-0.21
0.01-0.02
0.01-0.04
0.01-0.07
0.02-0 04
0.01-0.35
Source: Adapted from data by Manigold and Schulze (1969).
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CHAPTER 12 / PESTICIDE BURDEN AND SIGNIFICANCE / 187
samples were positive in the subsequent 2-year period. Concentration
values all were less than 1 ppb.
Lindane, dieldrin, and heptachlor epoxide were recovered most
frequently during the period October 1965 through September 1966.
During the following 2 years DDT, DDE, and the herbicide 2,4-D were
most commonly found. No explanation was offered for this difference
in frequency of recovery.
The concentration of chlorinated hydrocarbon insecticides in
water alone, however, does not necessarily correctly reflect the availa-
bility of these compounds to living components of the hydrosphere.
Studies in the major agricultural river basins of California have in-
dicated that an average pesticide concentration of 0.10 ppb to 0.20
ppb in water may mean that bottom sediments contain 20 ppb to 500
ppb of the compounds (Bailey and Hannum, 1967).
A pond near Denver was treated with 0.02 ppm of DDT, and the
insecticide was quantified in water, mud, vegetation, fish, and cray-
fish for 16 months (Bridges et al., 1963). As the DDT residues in the
water decreased to none detectable at 4 weeks, residues in the mud in-
creased to 8.3 ppm at 24 hours and disappeared in 12 months; vege-
tation residues were 30.7 ppm within 30 minutes and declined to 0.6
ppm at 12 months; rainbow trout, black bullhead, and crayfish still
contained DDT and the metabolites TDE and DDE at 16 months.
Quite clearly DDT is remarkably hydrophobic and does not re-
main in water in very large quantities. It does tend to concentrate
and persist in other compartments of the hydrosphere. Such data
give reason to pause and reconsider whenever the urge strikes to set
permissible limits for this and similar compounds in water alone
where the objective is to maintain a. suitable overall environment for
aquatic life.
SOURCES OF WATER CONTAMINATION
Pesticides may enter water in a variety of ways. These include
runoff from the land, industrial waste discharges, carelessness and
accidents, and by direct application to control unwanted plant and
animal pests (Nicholson, 1969). Other sources may be airborne resi-
dues, products of home use and garbage disposals (sewers), dumped
products containing residues higher than tolerances, dead animals
and animal excreta, and decaying plant tissues (Westlake and Gun-
ther, 1966). The significance of these additional sources remains to
be more fully documented, but their validity as sources is not ques-
tioned. Contamination may be more or less continuous, generally at
very low levels (less than 1 ppb), or in brief episodes that may reach
concentrations sufficient to kill fish and other aquatic life.
Runoff
Runoff from the land is probably the most widespread single
source of low level surface water contamination by pesticides and
has been demonstrated repeatedly (Nicholson et al., 1962; Hindin et
-------
188 / PART 3 / PESTICIDES AS WATER POLLUTANTS
al., 1964; Nicholson et al., 1964; Lauer et al., 1966; Nicholson et al.,
1966; Bailey and Hannum, 1967). Runoff may be more or less con-
tinuous throughout the year at levels generally less than 1 ppb or may
occur sporadically (Nicholson, 1969). Transport from land to water
may occur while the pesticide is adsorbed on eroded particulate mat-
ter, while in solution in runoff water, or by both means. It has been
shown that sodium humate, a common soil constituent, solubil'.zes
DDT in water (Wershaw, 1969). This phenomenon would be ex-
pected to facilitate the transport of DDT.
Factors that control the runoff of pesticides are the nature of the
pesticide and the extent to which it is used, edaphic considerations,
climatic factors, topography, and land usage and management prac-
tices. Pesticides having short half-lives do not possess the runoff po-
tential of persistent types. High-humus-type soils will yield less in-
secticide than will sandy soils (Lichtenstein, 1958). Heavy rainfall
immediately following application of chlorinated hydrocarbon-type in-
secticides is a classic cause of runoff that sometimes causes fish kills
(Young and Nicholson, 1951).
Industrial Waste
Perhaps the second most significant source of pesticides in water
is industry. The types of industries involved include producers of
basic pesticides, pesticide formulators, cooperage firms that reclaim
used pesticide drums, textile plants that moth-proof woolen yarns and
fabrics with dieldrin, and paper manufacturing industries that use
phenylmercury acetate (PMA) as a fungicide.
Releases from industrial sources may be continuous in manu-
facturing or process effluents, or occasional in high concentration slug
discharges following in-plant mishaps or breakdowns. In the latter
case, biological catastrophies may result in receiving streams.
As an example of a plant breakdown, an instance that occurred
in Alabama may be cited (Alabama Water Improvement Commission,
1961). A plant which manufactures parathion and methyl parathion
normally treats its wastes very effectively by neutralization with
strong alkali followed by double activated sludge treatment through
its own plant and that of a nearby city. During a breakdown in 1961
neither treatment plant could handle the load of toxic materials and
60% of the combined industrial effluent containing parathion and
city sewage was discharged untreated to a creek until corrective ac-
tion could be taken. Fish, turtles, and snakes died along 28 miles of
the stream whose average discharge at the time was 211 million gal-
lons a day at a velocity of 3A mile per hour. The creek entered the
Coosa River which then had an average discharge about 28 times
greater than that of the creek. Even with that dilution, traces of para-
thion residues were recovered 90 miles down the Coosa and some
lesser fish kills occurred in it. Unfortunately, water samples were
not taken for analysis until the third day after fish were first observed
dying. At that time a maximum 0.21 ppm of parathion was found at
a point on the creek 22 miles from the city. On that same day, 667
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CHAPTER 12 / PESTICIDE BURDEN AND SIGNIFICANCE / 189
ppm of parathion was reported in thickened sludge at the city sewage
treatment plant.
A second example involved a manufacturer of DDT who pro-
vided minimal waste treatment. The DDT content of water in a ditch
receiving these wastes was 0.1 ppm to 7.8 ppm. Bottom samples
analyzed from 0.6% to 2% DDT along the half-mile length of this
ditch after it had been carrying away wastes from this industr-al
plant for IVfe years.2
Barthel et al. (1969), in their study of pesticide residues in the
sediments of the lower Mississippi River and its tributaries, found 5
pesticide-formulating companies that dumped waste materials in
city sewers, in channels and sloughs near their plants, and on city
and privately owned dumps where they could be washed away by rain-
fall. Residues found included dieldrin, aldrin, endrin, isodrin, chlor-
dane, lindane, and DDT analogs and metabolities. Many of the resi-
dues in river bottom sediments were in concentrations less than 0.05
ppm, but some ranged in the thousands of ppm in the vicinity of in-
dustrial plants.
Accidents end Carelessness
Although strenuous efforts have been made within agricultural
and related industries to minimize accidents and carelessness with
pesticides, some instances of water pollution from these causes still
are reported. An instance of carelessness having potentially serious
human health implications occurred in Florida in 1964 (Florida State
Board of Health, 1964).
A rancher instructed his hired hand to dispose of approximately
50 four-pound bags of over-age 15% parathion dust. This was done
without the rancher's knowledge, by dumping them from a highway
bridge into the Peace River 1 mile upstream from the municipal water
intake of Arcadia, a town of about 6,000 people. The act was dis-
covered when boys fishing near the bridge hooked a bag and reported
it.
The town fortunately had an auxiliary well and immediately re-
verted to it. The citizens were instructed not to use the water, and
flushing of the mains was begun. Subsequent analysis of water sam-
ples showed that parathion concentration in the distribution system
was generally less than 1 ppb. However, a series of samples taken
from a tap at the local bus station ranged from 10 ppb to 380 ppb.
Investigation revealed that the bags of parathion had been
dumped in the river about 10 days before their discovery. They were
polyethylene lined and resisted rapid disintegration. All but 8 to 12
bags were eventually recovered. Those unrecovered bags that disin-
tegrated apparently did so over a period of several weeks. This may
have been the reason that residue levels sufficiently high to be a
threat to human health or the fish in the river did not occur. Para-
thion residue occurred in the river water for about 2 weeks after dis-
2. Charles Kaplan, FWPCA, Southeast Region, Atlanta, Georgia, per-
sonal communication.
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190 / PART 3 / PESTICIDES AS WATER POILUTANTS
covery at concentrations generally less than 1 ppb.
Accidents also have caused real or potential water pollution
problems. In March 1965, during the night, 2,500 to 3,000 pounds of
5% chlordane wettable powder spilled from a truck passing through
Orlando, Florida. After recovering what could be salvaged, about
1,300 to 1,700 pounds was hosed into the street's storm drainage
system from which it passed into a dry creek bed not far from one
of the city's lakes. When the potential for damage to the lake was
realized, the contaminated water and soil were removed for safe dis-
posal elsewhere.
Other Sources
The chemical control of aquatic weeds, rough fish, and aquatic
insect pests often results in some pesticide residue in water. These
activities are generally managed by professionals so that undesirable
consequences are minimized. Toxaphene, however, that was first used
for control of rough fish in lakes in the early 1950s has sometimes
caused trouble. Although toxaphene-treated lakes may generally be
restocked within 6 months to a year later, occasionally a lake may re-
main toxic to restocked fish for 5 years (Kallman et al., 1962; Terriere
et al., 1966). Such was the case at Miller Lake in Oregon that was
treated in 1958 at an estimated rate of 40 ppb. The initial residues
declined sharply to less than 2 ppb and remained near the level for
approximately 5 years (Terriere et al., 1966).
Airborne dust containing pesticides may also contribute to pesti-
cide levels in water either by direct deposition or by deposition on
land with subsequent runoff. Dust deposited on Cincinnati, Ohio, in
January 1965, originating from the southern high plains of Texas and
adjacent states, was shown to contain 0.6 ppm DDT, 0.5 ppm chlor-
dane, 0.2 ppm DDE, 0.2 ppm Ronnel, 0.04 ppm heptachlor epoxide,
0.04 ppm 2,4,5-T, and 0.003 ppm dieldrin (Cohen and Pinkerton,
1966).
Local drift of dusts and sprays from areas of pesticide applica-
tion is well known and can also be a source of water contamination.
Urban storm water has also been suggested as a carrier of pesti-
cides (Weibel et al., 1966). The significance of urban sites and activi-
ties as sources of water pollution by pesticides is now being investi-
gated at Michigan State University.
CONTROL OF PESTICIDE POLLUTION
Can anything practical be done to control water pollution by
pesticides? The answer is most definitely yes.
Point sources can be controlled most easily. These are industrial
sources where waste effluents enter watercourses through single or
adjacent outfalls. A variety of effective waste treatment systems are
now employed. Research and demonstration grant funds are availa-
ble through the Federal Water Pollution Control Administration for
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CHAPTER 12 / PESTICIDE BURDEN AND SIGNIFICANCE / 191
studies leading to the development of improved waste treatment mea-
sures. Research on chemical degradation of pesticides is expected to
result in knowledge that can be engineered into effective new treat-
ment technology.
Since the more persistent chlorinated hydrocarbon insecticides
are recognized as being more troublesome than less refractory pesti-
cides, their usage can be minimized or reserved for those purposes
where substitutes will not do.
Advanced concepts of pest control are being developed that
range from male sterilization techniques to use of micro quantities of
pesticides that are effective, yet not as wasteful of toxicants as are
present techniques. The acceptance of levels of pest control some-
what less than eradication also is being emphasized. The latter in-
volves reduction of pest population levels only to that point where
economic loss will not result.
Scientists at the Southeast Water Laboratory are working to de-
velop a means to predict runoff pollution and to prevent it from oc-
curring (Nicholson, 1969). The Universal Soil Loss Equation, de-
veloped by soil conservationists to guide conservation farm planning
throughout the United States, is being considered as the basis for a
new formula for predicting pesticide loss from the soil. Knowing
what to anticipate, control would be accomplished by using recom-
mended chemicals and practices.
REFERENCES
Alabama Water Improvement Commission. 1961. A report on fish
kills occurring on Choccolocco Creek and the Coosa River during
May 1961.
Bailey, T. E., and Hannum, J. R. 1967. Distribution of pesticides in
California. /. Sanit. Eng. Div. Am. Soc. Civil Engrs. 93 (SA5):
27-43.
Barthel, W. F., Hawthorne, J. C., Ford, J. H., Bolton, G. C., Mc-
Dowell, L. L., Grissinger, E. H., and Parsons, D. A. 1969.
Pesticides in water. Pesticide Monitoring J. 3:8-66.
Bridges. W. R., Kallman, B. J., and Andrews, A. K. 1963. Persistence
of DDT and its metabolites in a farm pond. Trans. Am. Fish-
eries Soc. 92:421-27.
Brown, E., and Nishioka, Y. A. 1967. Pesticides in selected western
streams—a contribution to the national program. Pesticide
Monitoring ]. 1:38-46.
Burdick, G. E., Harris, E. J., Dean, H. J., Walker, J. M., Skea, J., and
Colby, D. 1964. The accumulation of DDT in lake trout and
the effect on reproduction. Trans. Am. Fisheries Soc. 93:
127-36.
Cohen, J. M., and Pinkerton, C. 1966. Widespread translocation of
pesticides by air transport and rain-out. In Organic pesticides
in the environment, Ad-van. Chem. Ser. GO. Wash., D.C.: Am.
Chem. Soc.
Congressional Record—Senate (S9417) Aug. 8, 1969.
Florida State Board of Health. 1964. Report of Peace River para-
thion incident Dec. 23, 1964. Jacksonville: Bur. of Sanit. Eng.
-------
192 / PART 3 / PESTICIDES AS WATER POLLUTANTS
Gunther, F. A., Westlake, W. E., and Jaglan, P. S. 1968. Reported
solubilities of 738 pesticide chemicals in water. In Residue Re-
views, ed. F. A. Gunther, pp. 1-148. New York: Springer-
Verlag.
Henkin, H. 1969. Problems in PPM. Environment 11:25, 32-33,37.
Hickey, J. J., and Anderson, D. W. 1968. Chlorinated hydrocarbons
and eggshell changes in raptorial and fish-eating birds. Science
162:271-73.
Hindin, E., May, D. S., and Dustan, G. H. 1964. Collection and
analysis of synthetic organic pesticides from surface and ground
water. In Residue Revieivs, ed. F. A. Gunther, pp. 130-56.
New York: Springer-Verlag.
Kallman, B. J., Cope, O. B., and Navarre, R. J. 1962. Distribution
and detoxification of toxaphene in Clayton Lake, New Mexico.
Trans. Am. Fisheries Soc. 91:14-22.
Lauer, G. J., Nicholson, H. P., Cox, W. S., and Teasley, J. I. 1966.
Pesticide contamination of surface waters by sugar cane farm-
ing in Louisiana. Trans. Am. Fisheries Soc. 95:310-16.
Lichtenstein, E. P. 1958. Movement of insecticides in soils under
leaching conditions. /. Econ. Entomol. 51:380-83.
Mahan, J. N., Fowler, D. L., and Shepard, H. H. 1968. The Pesti-
cide Review 1968. Wash., B.C.: USDA, Agr. Stabilization and
Conserv. Serv.
Manigold, D. B., and Schulze, J. A. 1969. Pesticides in selected
western streams—a progress report. Pesticide Monitoring J.
3:124-35.
Nicholson, H. P. 1967. Pesticide pollution control. Science
158:871-76.
. 1969. Occurrence and significance of pesticide residues in
water. J. Wash. Acad. Sci. 59:77-85.
Nicholson, H. P., Webb, H. J., Lauer, G. J., O'Brien, R. E., Grzenda,
A. R., and Shanklin, D. W. 1962. Insecticide contamination
in a farm pond. I. Origin and duration. Trans. Am. Fisheries
Soc. 91:213-17.
Nicholson, H. P., Grzenda, A. R., Lauer, G. J., Cox, W. S., and
Teasley, J. I. 1964. Water pollution by insecticides in an agri-
cultural river basin. I. Occurrence of insecticides in river and
treated municipal water. Limnol. Oceanog. 9:310—17.
Nicholson, H. P., Grzenda, A. R., and Teasley, J. I. 1966. Water
pollution by insecticides: a six and one-half year study of a
watershed. Proc. Symp. Agr. Waste Waters, Rept. 10, pp.
132-41. Davis: Univ. of Calif.
Novick, S. 1969. A new pollution problem. Environment 11:3—9.
Porter, R. D., and Wiemeyer, S. N. 1969. Dieldrin and DDT:
effects on sparrow hawk eggshells and reproduction. Science
165:199-200.
Smart, N. A. 1968. Use and residues of mercury compounds in agri-
culture. In Residue Reviews, ed. F. A. Gunther, pp. 1—36. New
York: Springer-Verlag.
Terriere, L. C., Kiigemagi, U., Gerlach, A. R., and Borovicka, R. L.
1966. The persistence of toxaphene in lake water and its up-
take by aquatic plants and animals. /. Agr. Food Chem.
14:66-69.
Weaver, L., Gunnerson, C. G., Breidenbach, A. W., and Lichtenberg,
J. J. 1965. Chlorinated hydrocarbon pesticides in major U.S.
river basins. Public Health Rept. 80:481-93.
-------
CHAPTER 12 / PESTICIDE BURDEN AND SIGNIFICANCE / 193
Weibel, S. R., Weidner, R. B., Christiansen, A. G., and Anderson,
R. J. 1966. Characterization, treatment, and disposal of urban
stormwater. Third Intern. Conf. Water Pollution Res., Munich,
Germany. Section I, Paper 15, pp. 1-15. Wash., D.C.: Water
Pollution Control Federation.
Wershaw, R. L., Burcar, P. J., and Goldberg, M. C. 1969. Interac-
tion of pesticides with organic material. Environ. Sci. Teclmol.
3:271-73.
Westlake, W. E., and Gunther, F. A. 1966. Occurrence and mode
of introduction of pesticides in the environment. In Organic
pesticides in the environment, Advan. Chem. Ser. 60, pp.
110-21. Wash., B.C.: Am. Chem. Soc.
Young, L. A., and Nicholson, H. P. 1951. Stream pollution resulting
from the use of organic insecticides. Progressive Fish-Culturist
13:193-98.
-------
CHAPTER THIRTEEN,
HERBICIDE RESIDUES IN
AGRICULTURAL WATER FROM CONTROL
OF AQUATIC AND BANK WEEDS
F. L TIMMONS, P. A. FRANK, and R. J. DEMINT
H
I ERBICIDES are essential and widely used tools in our modern
agriculture. In 1964 approximately 120 million acres of cultivated
fields, pastures, grazing lands, and forested areas were treated with
200 million pounds of herbicides for weed control (U.S. Department
of Agriculture Census, 1964). In 1967 the total sales of herbicides
had increased to 348 million pounds. A small but relatively signifi-
cant proportion of those herbicides were used to control weeds in
irrigation and drainage canals, on ditchbanks, in farm ponds, and
in irrigation reservoirs.
Thus far, monitoring studies have shown few significant herbi-
cide residues in our streams, ponds, and lakes resulting from runoff
from treated fields, rangelands, and forests. There is some concern
about the effects on water quality of herbicides appied directly into
or over the water or on adjacent banks from which drift, overlap
spray, or runoff may get into surface water supplies.
This chapter reports the extent of herbicide use for control of
aquatic and bank weeds, the levels of residues found in water after
such applications, the rate of dissipation of such residues, and
whether and to what extent herbicides in irrigation water are found
in irrigated crops used for food or feed. Only limited information
is presented on herbicide residues in water from other sources.
EXTENT OF HERBICIDE USE FOR CONTROL OF AQUATIC AND
BANK WEEDS
No statistics are available on the total amount of herbicides used
annually in the United States for control of aquatic and bank weeds.
However, several examples of the extent of aquatic areas where
weeds are serious problems and the amount of herbicides used in
F. L. TIMMONS is Research Agronomist, Crops Research Division,
ARS, USDA, Laramie, Wyo. P. A. FRANK is Plant Physiologist, Crops
Research Division, ARS, USDA, Denver. R. J. DEMINT is Research
Chemist, Crops Research Division, ARS, USDA, Denver.
194
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CHAPTER 13 / HERBICIDE RESIDUES / 195
certain areas provide reliable indications of the total amounts used
in and adjacent to water.
About 150 species of aquatic and semiaquatic marginal plants
create weed problems in one or more aquatic situations in the United
States (Timmons, 1967). According to the latest available statistics
(U.S. Department of Agriculture Census, 1959, 1964), there are
more than 2 million ponds and reservoirs, 189,000 miles of drainage
ditches, and 173,000 miles of irrigation canals. Most of the ponds
and drainage ditches are in the north-central and southern states.
Three-fourths of the irrigation canals and most of the reservoirs
which supply irrigation water are in the western states. The
numerous reservoirs in the southern and north-central states are used
primarily for recreation and municipal purposes. All of these aquatic
areas are infested or susceptible to infestation by aquatic and bank
weeds.
In 1957 a careful survey was conducted by the Agricultural Re-
search Service and the Bureau of Reclamation (Timmons, 1960) to
determine the extent of weed infestation, annual losses caused by
weeds, and the cost of weed control on irrigation systems of the 17
western states. The survey revealed that 63% of the 144,000 miles of
canals were infested with aquatic weeds. More than 759c of the
530,000 acres of ditchbanks were infested with 1 or more of 4 kinds
of bank weeds. In that year, 54% of the weed-infested canals and
80% of the weed-infested ditchbanks were treated for weed control,
mostly with herbicides.
A questionnaire survey made in 1961 (Timmons, 1963) among
agencies and aquatic weed specialists revealed that aquatic and mar-
ginal weeds were serious problems in most ponds and drainage
ditches in the north-central, southern, and western states. The ex-
tensive annual losses from lack of drainage and water utilization
caused by those weeds were reported in Agriculture Handbook 291,
Losses in Agriculture, 1965.
An extensive weed control program has been continued since
1957 on western irrigation systems. The herbicides used most ex-
tensively in the control programs are xylene; (2,4-dichlorophenoxy)
acetic acid (2,4-D); (2,4,5-trichlorophenoxy) acetic acid (2,4,5-T);
copper sulfate; 2,2-dichloropropionic acid (dalapon); and 3-amino-s-
triazole (amitrole). Aromatic weed oils are used extensively in the
southwestern states. The amounts of herbicides ordered by irrigation
districts in Oregon, Washington, and Idaho for use on irrigation
systems during 1969 were xylene, 800,000 gal; acrolein, 22.000 gal;
copper sulfate, 216,000 lb; 2,4-D, 187,000 lb; 2,4,5-T, 9,200 lb;
dalapon, 3.500 lb; and amitrole + ammonium thiocyanate (amitrole-
T), 5,000 lb.1 This is for only 3 of the 17 western states. Most of
the other western states do not use herbicides as extensively as do
the 3 northwestern states.
General information indicates that weed problems in drainage
ditches of eastern states are as critical and probably more so than
those in western irrigation systems. However, the use of herbicides
does not seem to have been as extensive for control of weeds in those
drainage ditches except possibly in Florida and Louisiana. Mechani-
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196 / PART 3 / PESTICIDES AS WATER POLLUTANTS
cal methods have not proved to be adequate substitutes for herbicides
in drainage ditches and ponds in those states.
Irrigation and drainage of agricultural land are important fac-
tors in the conservation and use of water resources in the south-
eastern states. The aquatic weed problems in lakes, streams, and
water-control canals in that region are much more extensive and
serious than in the north-central states. A survey was conducted in
1963 in 8 Gulf and South Atlantic Coast states (U.S. Department of
the Army, 1965). The survey showed total infestations of 162,000
acres of water hyacinth (Eichhornia crassipes [Mart.] Solms). 99,000
acres of alligator weed (Alternanthera philoxeroides [Mart.] Griseb.),
and 207,000 acres of submersed weeds. The survey did not include
farm ponds and tidal marsh areas, most of which are heavily in-
fested by aquatic and marginal weeds in those states.
Herbicides, chiefly 2,4-D, have been used extensively since about
1950 for the control of water hyacinth and certain other floating
and emersed weeds in Florida and Louisiana. During the extensive
unrestricted use of 2,4-D prior to 1967, no serious problems of injury
to fish, livestock, or man from use of treated water were apparent.
During the 4 years 1959-62, approximately 188,000 acres of water
hyacinth and alligator weed were sprayed with 2,4-D in the U.S.
Army Corps of Engineers Expanded Aquatic Plant Control Program.
That did not account for the herbicide usage by other agencies and
private individuals during those years.
Aquatic herbicides such as 2,4-D; 6,7-dihydrodipyrido[l,2-a:2',
l'-c]pyrazinediium salts (diquat); 7-oxabicyclo[2.2.1]heptane-2,3-di-
carboxylic acid (endothall); dalapon; and 2-(2.4,5-trichlorophenoxy)
propionic acid (silvex) are used to a considerable extent in the south-
east, especially in Florida. The highly successful aquatic and mar-
ginal weed program of the Central and Southern Flood Control Dis-
trict is an excellent example of what can be accomplished by
extensive and careful use of all available registered herbicides for
control of aquatic and marginal weeds.
At present 6 herbicides are registered by the Pesticides Regula-
tion Division of the Agricultural Research Service for control of
algae, 4 for control of floating weeds, 6 for control of emersed weeds,
and 12 for control of submersed weeds. In addition, 17 herbicides
are registered for control of ditchbank weeds. That is a total of 35
different herbicides registered for the control of aquatic or bank
weeds.
HERBICIDE RESIDUES IN WATER
The principal means by which herbicides enter water are (1)
from surface-runoff water during irrigation or rainfall; (2) by appli-
cation of herbicides to soil or water for control of submersed weeds in
canals, ponds, or lakes; (3) by herbicide treatment of floating and
emersed weeds, and (4) from treatment of banks of streams and
canals for control of bank and marginal weeds.
1. W. D. Boyle, Bureau of Reclamation, Boise, Idaho, 1969, personal
communication.
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CHAPTER 13 / HERBICIDE RESIDUES / 197
Residues in Surface Runoff
During a 3-year program of monitoring agricultural pesticide
residues, herbicides were found only rarely, and usually in concen-
trations less than 10 ppb (U.S. Department of Agriculture, 1969).
Monitoring studies in an area of irrigated agriculture showed that
before use, irrigation water contained very small quantities (<1 ppb)
of pesticides of any kind. Of a number of herbicides used in the area
monitored, no detectable residues of these were found in waste irri-
gation water.
In other monitoring studies (Marston et al., 1968) small quanti-
ties of amitrole were detected in runoff water for 5 days following
aerial spraying of a 100-acre watershed for control of salmonberry.
A maximum concentration of 155 ppb amitrole was found 30 min-
utes after spraying began, but was reduced to 26 ppb after 2 hours.
On the other hand, amitrole was found in runoff water for only 35
hours from a similar but larger watershed treatment (Norris et al.,
1967). When 2.1 acres of a 46.5-acre rangeland watershed were
treated with 9.3 Ib per acre of 4-amino-3,5,6-trichloropicolinic acid
(picloram), the runoff water from this watershed contained picloram
in concentrations of 0.37 to 0.046 ppm for 11 months (Davis et al.,
1968). No picloram was found after this period. Concentrations of
1.5 to 2.0 ppm of 2,4-D were detected in runoff water for a period of
7 days following treatment of 150 acres of forest with 40 Ib per acre
of the nonyl ester of 2,4-D (Aldhous, 1967). In a subsequent sam-
pling of the runoff water 28 days after treatment, the residue of
2,4-D was below the detectable level of 0.005 ppm.
Experimental data showing the extent of herbicidal residues in
runoff water are limited. Where residues were shown to occur, in
most cases the total volume of water affected was not large.
Residues in Water from Control of Submersed Weeds
Recommendations for control of submersed weeds usually
specify herbicide-usage levels in terms of ppm of the herbicide in
water. Therefore, the initial residue level most often represents the
recommended or predetermined concentration of herbicide found to
be effective for control of the weed species present. A number of
herbicides and recommended application rates for control of sub-
mersed weeds are given in Table 13.1.
Submersed weed control in waterways such as irrigation canals
is accomplished primarily by the use of acrolein, aromatic solvents,
and copper sulfate. Diquat, endothall, and the ester of 2,4-D are
used less frequently. Copper sulfate is commonly used for control
of algae; however, low concentrations applied over extended periods
have been reported recently to provide good control of vascular weeds
(Bartley, 1969). Where very little water movement occurs in water-
ways, good weed control is obtained with diquat and the amine salts
of endothall.
When maximum possible herbicide residues were found in water
from the applications recommended in Table 13.1, all of the applied
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198 / PART 3 / PESTICIDES AS WATER POLLUTANTS
TABLE 13.1. Herbicides and application rates recommended for control of
submersed aquatic weeds.
Herbicide
Acrolein
Aromatic solvents ....
Copper sulfate . . .
Dichlobenil
Diquat
Endothall
Fenac
Silvex
2,4-D ester
Form
Liquid
Emulsified
Pentahydrate
Granular
Cation
Disodium salt
Amine salt
Granular
Potassium salt
Granular
Application Rates*
0.1-0.6 ppmt
4-7 ppm|
600-740 ppm§
0 1-2.0 ppm
10-15 Ib/a
0.9-1.4 ppm [|
0.25-1.5 ppm
0.5—4 ppm
0.05-2.5 ppm
15-20 Ib/a
1.4-1.8 ppmll
1.5-2 ppm
20-40 Ib/a
1.8-3.6 ppm|[
* From USDA (1969) Suggested Guide for Weed Control. Agr. Handbook
332. Application rates are in terms of acid equivalent or active ingredient.
t For extended application time in flowing water.
$ For treatment of weeds in quiescent water.
§ Emulsifier added at concentrations of 1.5 to 2.0%.
|| Ppm concentration arbitrarily expressed in terms of 4 ft of water.
herbicide recovered in water usually dissipated rapidly. Volatile
herbicides such as acrolein and aromatic solvents (mostly xylene)
are lost from water at relatively rapid rates. Diquat concentrations
are rapidly reduced by weed growth, organic matter, and sediment
(Coats et al., 1966). Granular formulations may prevent occurrence
of high concentrations of certain herbicides in water by confining
portions of the herbicides at the hydrosoil surface. Granular formu-
lations of 2,6-dichlorobenzonitrile (dichlobenil) and the ester of
2,4-D are notable in this respect. Following treatment of 2 ponds
with 0.58 and 0.40 ppm of granular dichlobenil, only 0.32 and 0.23
ppm, respectively, were recovered (Frank and Comes, 1967). Like-
wise, in a pond treated with 1.33 ppm of granular butoxyethanol
ester of 2,4-D, the maximum residue level of 2,4-D observed was
0.067 ppm. At the same time, relatively high concentrations of both
herbicides were found in the upper 1 inch of hydrosoil. On the
other hand (2,3,6-trichlorophenyl) acetic acid (fenac) was rapidly lost
from granules and nearly all of the herbicide applied was found in
water above the granules which remained at the bottom of the pond
or lake. During 1966 the Tennessee Valley Authority used large-scale
applications of granular butoxyethanol ester of 2,4-D at rates of 40
to 100 Ib per acre for control of Eurasian watermilfoil (Myriophyllum
spicatum L.). The highest concentration of 2,4-D recorded at any
of the water-treatment plants where water was monitored was 2 ppb
(Smith and Isom, 1967).
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CHAPTER 13 HERBICIDE RESIDUES / 199
Residues in Water from Control of Floating Weeds
Herbicide residues resulting from treatment for control of float-
ing weeds are dependent not only on the application rate and water
depth but also on the type of floating weeds and the amount of
exposed water surface. Very few residue data on these applications
are available.
In one series of experiments, pools 10 feet in diameter contain-
ing growths of alligator weed were sprayed with propylene glycol
butyl ether (PGBE) ester of silvex at 8 Ib per acre TCochrane et al..
1967). Highest possible concentrations of silvex residues would have
ranged from 2.70 to 3.04 ppm if all of the herbicide applied was
found in the water. However, the greatest recovery of silvex in
water at any time was approximately 1.6 ppm. In this study no
estimates of uncovered water surface were made. In similar studies
involving applications of the dimethyl amine salt of 2.4-D and the
PGBE esters of 2.4-D and silvex applied at 4 Ib per acre on water
hyacinth or alligator weed, almost all of the maximum residue
levels were between 1 ppm and 650 ppb (Averitt. 1967). In both
of the above studies, the highest concentrations of herbicides did
not appear in the water until approximately 1 to 2 weeks after the
treatments. The authors concluded that the herbicides were absorbed
by the plants and later released into the water through roots and
other submersed plant tissues.
Residues from Ditchbank Weed Control
Spreading weed infestations have caused irrigation system man-
agers and maintenance workers to become more conscious of weed
control on banks of waterways. Where periodic treatment with
2.4-D was once considered adequate for ditchbank maintenance.
extensive and varied weed control programs involving other herbi-
cides or mixtures are now common. Among the most serious ditch-
bank weeds are several species such as sedges—for example. Carex
aquatilis Wahl and reed canary grass (Phalaris arundinacea L.")—
which grow at the water margin. The proximity of weeds to water
almost invariably results in some herbicide entering the water during
herbicide application. Principal factors affecting the amount of
herbicide found in the water are treatment rate, water volume, na-
ture of the weed growth, and spray overlap at the water's edge.
A number of ditchbanks were sprayed with various herbicides
and the water sampled and analyzed to determine the quantities
of residues present (Trank and Demint. 1967. 1968). Herbicides.
treatment rates, and water volumes, along with the highest concen-
trations of herbicides found in the water of a number of irrigation
waterways, are shown in Table 13.2. With one exception, all treat-
ments were made on 1 bank, with a vehicle-mounted boom traveling
in an upstream direction. Both banks of the Boulder Feeder Canal
were treated prior to the entry of water. The 98 ppb of amitrole
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200 / PART 3 / PESTICIDES AS WATER POLLUTANTS
TABLE 13.2. Highest concentrations of residues found in irrigation water
following ditchbank treatment with several herbicides.
Herbicide and Irrigation Treatment Volume of
Waterway Rate Water Flow
Highest
Concentration
of Residue
(Ib/a)
(cfs)
(ppb)
Amitrole
Boulder Feeder Canal* . .
Farmer's ditch
Manard lateral
Yolo lateral
Dalapon
Five-mile lateral
Lateral no. 4
Manard lateral
Yolo lateral
TCA
Lateral no. 4
Manard lateral
Yolo lateral
2,4-Dt
Lateral no. 4
Manard lateral
Yolo lateral
6
4
4
3
20.0
, 6.7
9.6
, 10.5
3.8
5.4
5.9
1.9
2.7
3.0
50
4
40
23
15
290
37
26
290
37
26
290
37
26
98
24
31
43
399
23
39
162
12
20
69
5
13
36
Source: Unpublished data from P. A. Frank and R. J. Demint, Annual
Report of Weed Investigations. USDA, ARS, Denver, Colo.
* Both banks treated for distance of 0.7 mile.
t N-oleyl 1,3-propylenediamine salt.
represent the herbicide picked up by the initial water filling the canal
and were of very short duration. Minimum and average residue
values for all treatments were considerably less than the maximum
levels shown in the table. It will be shown later that residues in the
concentrations listed in Table 13.2 would be most unlikely to injure
crops or produce significant residues in crop plants.
DISSIPATION OF HERBICIDE RESIDUES FROM WATER
Dissipation is an extremely important factor in the use of herbi-
cides for control of aquatic and bank weeds. Most of the herbicides
registered for use in aquatic situations have water-use restrictions
which require at least partial dissipation of the herbicide before
normal water use is resumed. The pathways leading to dissipation
are almost as varied as the chemicals themselves. Volatilization is
the most important factor in the dissipation of aromatic solvents and
acrolein. Sorption processes predominate in the disappearance from
water of herbicides such as diquat, paraquat, and possibly endothall.
Biological and chemical degradation account for much of the loss of
2,4-D, silvex, dichlobenil, and other herb cides.
The dissipation of herbicides in water has been studied most
extensively in small ponds, pools, and reservoirs. Data from some of
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CHAPTER 13 / HERBICIDE RESIDUES / 201
TABLE 13.3. Residue dissipation in ponded water following application of
herbicides.
Herbicide
Application
Rate
Concentration Detected
Highest
Final
(ppm) (ppm) (days)
Liquid applications
Amitrole* 1.0 1.34 1.0
Fenac* 4.0 5.2 1.0
Diquat* 2.5 3.27 2.0
Paraquat* 2.1 1.05 1.0
2,4-D methylamine saltt .... 1.5 0.139 1.0
Silvex, PGBE estert§ 2.9 1.6 7.0
Diquatjl 0.62 0.49 1.0
Paraquatil 1.14 0.55 1.0
Endothall|| 1.0 0.18 2.0
Copper^ ' 0.50 0.42 0.1
Endothall** 1.2 0.79 4.0
Granular applications
(ppm) (days)
0.08
2.4
N.D.
N.D.
0.004
0.02
0.001
O.C01
0.001
0.19
0.54
201
202
30
38
41
182
8
12
36
3
12
DichlobenilH
Dichlobenil||
Fenacl|
Fenaci
2,4-D butoxyethanol ester|| . . .
0.58
0.40
1.56
1.0
1.33
0.32
0.23
1.61
0.71
0.067
36
8
18
8
18
0.004
O.C01
0.38
0.07
0.001
160
160
160
160
36
* Grzenda, Nicholson, and Cox (1966).
+ Averitt (1967).
i Cochrane et al. (1967).
•? Average of three treatments.
j Frank and Comes (1937).
1 Toth and Riemer (1968).
** Yeo (1969).
the more typical studies were compiled and are shown in Table 13.3.
Some of the most effective aquatic herbicides, such as dichlobenil,
fenac, and silvex, were found to be among the more persistent com-
pounds. The excellent and often complete control of weeds by these
herbicides may be attributed in part to their persistence. Diquat,
paraquat, 2,4-D, and endothall disappeared from ponded water at
rapid to moderate rates. While rapid dissipation from water is desir-
able from the standpoint of residues, it may also result in the total
ineffectiveness of diquat and paraquat in waters containing sus-
pended sediment or organic matter (Coats et al., 1966). In some
cases dissipation of the herbicides from water was found to be ac-
companied by accumulation of high concentrations of the herbicides
in the hydrosoil (Frank and Comes, 1967).
Dissipation of herbicide residues in the flowing water of canals,
ditches, and streams has been studied less extensively than in ponds
and very few data are published. Most of the studies reported here
were carried out recently by personnel of the Agricultural Research
Service and cooperators.
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202 / PART 3 / PESTICIDES AS WATER POLLUTANTS
While aromatic solvents have been used many years for control
of submerged weeds in irrigation canals, it was not until 1967 that
the dissipation of this herbicide was studied in some detail (Frank
and Demint, 1967). Two canals carrying 11 and 13 cubic feet per
second (cfs) of water were treated with 575 and 550 ppm emulsified
xylene, respectively. Loss of xylene, largely by way of volatilization,
was rapid. After traveling 9 miles, the concentration of xylene in
the canal treated at the rate of 550 ppm was reduced to 17 ppm.
The concentration of xylene in the second canal was reduced to
6 ppm after a downstream flow of 8 miles.
Acrolein is another highly volatile herbicide and is used for
control of submersed weeds in large irrigation canals. The loss rate
of acrolein from concentrations of 0.6 and 0.7 ppm was determined
for a canal carrying 132 to 135 cfs of water (Battelle-Northwest
Laboratories, 1966, 1968). In 2 tests, the loss of acrolein was shown
to be temperature dependent. In water of 64° F the original concen-
tration of 0.7 ppm of acrolein was reduced by 98% while the water
traveled a distance of 19 miles. At the lower and less typical tem-
perature of 48° F, the loss was only 62% at a distance 27 miles
downstream from the point of application. The dissipation data of
both aromatic solvent and the acrolein showed a linear relationship
between the log of the herbicide concentration and distance of water
flow downstream.
Copper sulfate is frequently used to control algae in irrigation
canals. The commonly used slug treatment of 1 Ib of copper sulfate
pentahydrate per cfs of water flow, when applied to a 411-cfs canal
in Washington, gave concentrations of 1.6, 0.36, 0.23, and 0.04 ppm
at 0.5, 6, 12, and 23 miles downstream, respectively (Nelson et al.,
1969). A 3-year study was made to determine the efficacy of daily
application of copper sulfate for control of submersed weeds in irri-
gation canals (Bartley, 1969). Five pounds of copper sulfate were
applied per hour to a flow of 26 cfs of water. An average maximum
concentration of 0.21 ppm copper ion was found 0.25 mile below
the treatment site. The copper ion concentration was reduced 86%
to 0.03 ppm 9 miles downstream.
In one study a single bank of each of 2 irrigation laterals was
sprayed with amitrole in an upstream direction for a distance of 0.5
mile. Treatment rates were 3 and 4 Ib per acre. Overlap of the spray
pattern at the water's edge was estimated to vary from 12 to 24
inches. Water samples taken at varying distances downstream from
the area treated with 4 Ib per acre of amitrole showed a reduction in
residue levels from 31 to 24 ppb over a 4.5-mile distance of water
flow. Reduction of amitrole residue from the bank treated at the
rate of 3 Ib per acre was 43 to 26 ppb over a distance of water flow
of 3 miles.
Frequently it is necessary to treat canal banks for weed control
prior to filling with water for the growing season. One such canal
was treated with a 4-foot swath on both banks for a distance of 0.7
mile. On turning 50 cfs of water into the canal, an initial concen-
tration of 98 ppb of amitrole occurred in the water front. This resi-
due level was reduced to 46 ppb at 1.3 miles downstream and after
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CHAPTER 13 / HERBICIDE RESIDUES / 203
TABLE 13.4. Dissipation of herbicides in irrigation wafer.
Miles Downstream Dalapon TCA 2,4-D
(ppb) (ppb) (ppb)
Manard lateral
0.5 66 31 25
4.25 40 20 14
Yolo lateral
0.5 289 ... 55
3.0 182 ... 36
flowing 9 miles, the residue level in the water amounted to only
23 ppb.
Two irrigation laterals (Yolo and Manard) were treated with a
commonly used mixture of herbicides. A study was made of the
resulting residue levels in the water and the extent of dissipation of
these levels as the water traveled downstream. Water volume and
the treatment rates of dalapon, trichloroacetic acid (TCA), and 2,4-D
used are shown in Table 13.2. Residue levels in the irrigation water
0.5 mile below the treatment sites and at the ends of the laterals are
shown in Table 13.4. The input of herbicide during bank treatments
such as these was quite variable. At any instant it may vary as
much as ± 100% of the average or calculated input. Also, as the
water traveled downstream, water containing the maximum residue
level became a smaller fraction of the total volume of residue-bearing
water. For this reason values based on the average residue levels
may reflect more accurately the dissipation of herbicides in flowing
water.
In other studies, dalapon, amitrole-T, and the isooctyl ester of
2,4-D were applied directly to irrigation water at constant rates, and
reduction in residue levels was determined as the water flowed down-
stream. A canal which carried 16 cfs of water was sprayed for 75
minutes to provide a mile of water containing 400 ppb of 2,4-D.
The dissipation of residues of 2,4-D was nonlinear. The 400 ppb
were reduced to maximum residue levels of 383, 285, 210, 206, and
190 ppb at distances of 0.1, 1, 3, 5, and 8 miles downstream, respec-
tively. These data show an initial rapid loss during the first 3 miles
of water flow, followed by a slow but constant decrease up to 9 miles.
Another canal, which carried 19 cfs of water, was sprayed with
a solution of the sodium salt of dalapon for 51 minutes to provide a
mile of water containing 100 ppb of dalapon. A plot of maximum
concentration in ppb against mileage gave a straight line with a
slope of 5.6. Another canal which carried 49 cfs of water was simi-
larly treated for 18 minutes with amitrole-T to provide a half-mile
length of water containing 50 ppb of amitrole (Demint et al., 1969).
A similar plot, for the 5.25 miles sampled, gave a straight line with
a slope of 6. Using these rates of dissipation, downstream mileage
at which total dissipation might occur was calculated as 18 miles for
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204 / PART 3 / PESTICIDES AS WATER POLLUTANTS
dalapon and slightly under 9 miles for amitrole. The conformance
to linearity was an indication that only 1 factor was involved for
these 2 water-soluble herbicides. Dissipation was achieved through
elongation of the herbicide cloud. The magnitude of the dilution
was so great as to obscure possible losses from sorption or degrada-
tion. Caution should be exercised in attempting to use these dissipa-
tion rates to predict the complete disappearance of these herbicides
to other canals. Among the complicating factors are time required
for complete dispersion, canal capacity changes attendant with flow
rate changes, the retarding effect of bank treatments compared with
idealized applications to the center of the canal, and length of bank
treatments.
HERBICIDES IN IRRIGATED CROPS
Nearly all of the herbicides used for weed control in irrigation
canals or on canal banks have been tested on most of the important
field crops at 1 to 4 of our Agricultural Research Sendee research
stations in the western states (Arle, 1950; Bruns, 1954; Bruns et al.,
1955, 1958, 1964; Arle and McRae, 1959). The treated water was
applied by flood or furrow irrigation methods in 1 to 3 acre-inches
of water.
In general, xylene-type aromatic solvents, acrolein, amitrole,
and dalapon were found to cause no injurious effects on crop growth
or yields at concentrations or rates used for weed control. Even
2,4-D at rates up to 1 Ib, and usually 2 Ib, per acre did not affect
growth or yields of such sensitive crops as cotton, grapes, and sugar
beets.
The results of this research have verified the extensive experi-
ence and observation in connection with the widespread use of
irrigation water on crops from canals treated with aromatic solvents,
acrolein, or copper sulfate and on which bank weeds were treated
with 2,4-D, dalapon, amitrole, 2,4,5-T, or silvex. No known substan-
tiated instances of damage to crops by any of the extensive uses
during 5 to 20 years have been reported. This extensive use and
experience have been documented in annual weed and pest control
reports of the 7 Bureau of Reclamation regional offices.
In 1966 equipment was developed at Prosser, Washington, for
field application to crops by sprinkler irrigation of water containing
herbicides. This provided an opportunity to compare the effects of
herbicides in water on irrigated crops when applied by overhead
sprinkler and furrow methods. It also provided an opportunity to
compare the amounts of herbicide residues assimilated by the crops
when treated water was applied by each of the 2 methods.
In 1967. 2,4-D and silvex were applied to crops at rates of 0.1.
0.5, and 2.5 Ib per acre by furrow irrigation. These rates provided
concentrations of 0.22, 1.11, and 5.55 ppm, respectively, in 2 acre-
inches of water. Only at the highest rate of silvex did significant
yield reductions occur in beet tops and bean seed. Small but statis-
tically nonsignificant reductions were measured in beet tops and
roots for the 2 highest rates of 2,4-D. There was no reduction in
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CHAPTER 13 / HERBICIDE RESIDUES / 205
yield of corn fodder or grain by either herbicide at any of the 3 rates.
Both 2,4-D and silvex were applied at rates of 0.01, 0.1, and 1.0
Ib per acre by sprinkler irrigation. These rates provided concentra-
tions of 0.022, 0.22, and 2.22 ppm in 2 acre-inches of irrigation
water. Surprisingly, both 2,4-D and silvex produced significant in-
creases in the yields of sugar beet tops and roots at all 3 rates.
Neither 2,4-D nor silvex affected the yield of corn. The 2 highest
rates of silvex reduced the yield of soybean seed, but the lowest rate
of silvex and none of the rates of 2,4-D reduced the yield of soybeans.
The rates for sprinkler irrigation were lower than those used for fur-
row irrigation.
In samples taken 7 days after furrow irrigation, the highest
rate of 2,4-D resulted in a residue of 0.11 ppm in beet roots, fresh
weight (Bruns and Comes, 1968). No residues were found in other
crop tissues. Samples of crop tissues taken at maturity showed no
residues of either herbicide after irrigations containing 0,22 or
1.11 ppm.
Low concentrations of 2,4-D were found in most crop tissues in
samples taken 2 days after sprinkler irrigation at all rates. However,
the highest concentrations from the 2 lower rates ranged up to 3.94
ppm dry weight basis in beet roots. These concentrations were
lower than the tolerance of 5 ppm already established for 2,4-D in
some food and feed crops. Also, sugar beet roots would never be
used for feed or sugar production at that stage of growth. It is pos-
sible that sweet corn roasting ears or soybeans as hay might be
harvested at that immature stage of growth. At maturity, when all
of these crops are usually harvested, none of the crops contained
any 2,4-D from the 2 lower rates and only beet roots contained 0.06
ppm from the highest rate, 1 Ib per acre (2.22 ppm). This is 40 to
50 times the highest concentration of 2,4-D found in water thus far,
following applications for control of aquatic or bank weeds.
No silvex residues were found in any crop tissue receiving the
lowest rate of 0.1 Ib per acre (0.22 ppm). By normal harvest time at
crop maturity, most of the silvex residues had disappeared, even in
crops irrigated with the highest concentration.
Silvex residues in crop tissues following sprinkler irrigation
were found in all crop tissues from the 2 highest rates in samples
taken 2 days after harvest. Also, soybean and corn foliage and beet
roots contained measurable residues from the lowest rate. However,
by normal harvest date at crop maturity, no residues were present in
any crop tissues from the 2 lower concentrations of 0.022 and 0.22
of silvex in irrigation water.
Additional data on residues of 6 different herbicides in 6 differ-
ent irrigated crops are being obtained in our contract research with
Stanford Research Institute. In this contract the crops were grown
in 2-gallon greenhouse crocks. Each crop was irrigated at early
growth and late growth stages with 2 concentrations of each herbi-
cide. The treated water was applied in 1 acre-inch by both flood
or soil and overhead sprinkler irrigation methods. Results are now
available on 5 of the herbicides in all 6 crops (Stanford Research
Institute, 1968, 1969).
No 2,4-D was found in onions or soybeans from the highest
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206 / PART 3 / PESTICIDES AS WATER POLLUTANTS
rates of 0.22 and 1.11 ppm and the residues were negligible in car-
rots, milo, or potatoes. Even in leaf lettuce the residues were less
than one-tenth the tolerance established for 2,4-D on some food crops.
No silvex was found in milo, carrots, or lettuce from the highest
concentrations of 0.22 and 1.11 ppm, and residues were very low in
potatoes, soybeans, and onions.
No amitrole residues were found in any of the tissues of green-
house-grown and treated crops or in field-grown beans, corn, and
wheat at Bozeman, Montana, which were furrow irrigated with water
containing 4 Ib per acre of amitrole. In another experiment at
Prosser, Washington, no amitrole residues were found in crops fur-
row irrigated with water containing up to 2.5 Ib per acre of amitrole
(Bruns and Comes, 1966).
The dalapon residues were determined in greenhouse-grown
crops treated and analyzed by Stanford Research Institute. The high-
est rate used was 0.5 Ib per acre (2.22 ppm) except on potatoes, car-
rots, and onions. For the latter 3 crops, the rates were increased 5-
fold. Despite the heavy rates of treatment on carrots and onions, the
dalapon residues were very low. The highest concentrations of
dalapon were in soybeans, 1.18 to 2.79 ppm. These concentrations
were less than one-tenth the tolerance of 30 ppm of dalapon estab-
lished by the U.S. Food and Drug Administration for asparagus.
No diquat was found in any of the 6 crops which were irrigated
by soil-flooding or overhead sprinkling at 0.09 or 0.45 ppm. Because
of the rapid dissipation of diquat in water, irrigation water would
seldom, if ever, contain a residue of 0.45 ppm following a normal
application for weed control.
The same equipment that was used at Prosser, Washington,
for comparing effects and residues from furrow and sprinkler irriga-
tion of 2,4-D and silvex in 1967 was used for comparing furrow and
sprinkler irrigation of acrolein in 1966, and again in 1968 (Bruns
and Comes, 1966, 1968). The concentrations used were 0.1, 15, and
60 ppm in 1966 and 0.1, 0.6, and 15 ppm in 1968. Only the highest
concentration, 60 ppm by furrow irrigation, caused injury to soybean
and sugar beet foliage. The injury from sprinkler irrigation was
greater than that from furrow irrigation but no injury occurred from
concentrations used for weed contol. None of the furrow irrigation
treatments reduced corn yields. Analyses of water samples showed
that only 5 to 10% of the acrolein was lost from the water during
furrow irrigations. However, 60 to 90% of the acrolein was lost from
the water during sprinkler irrigation before the water fell on the crop
plants. That probably explains why no damage to crops was ever
reported by farmers who applied acrolein-treated water directly from
canals by sprinkler irrigation. Battelle Laboratories found no acrolein
in any of the crop samples.
SUMMARY
The effectiveness of herbicides and the economics involved in
agricultural production have caused their extensive use for weed
control in and adjacent to aquatic areas, especially on irrigation
-------
CHAPTER 13 / HERBICIDE RESIDUES / 207
systems. As additional data concerning residues and toxicity are
developed, and as adequate tolerances are established for residues,
greater use of herbicides in and around agricultural waters may be
expected.
Maximum residues of herbicides used for weed control in farm
ponds and reservoirs are low, ranging from a fraction of 1 ppm to
several ppm. In most cases these levels are of short duration. With
the exception of aromatic solvents and copper sulfate, most herbi-
cides occur in irrigation water at concentrations under 100 ppbJ
Only under the most adverse conditions in small irrigation laterals
are significantly greater residues found. The transport of herbicide
residues in irrigation water prevents extensive exposure of any given
irrigated area. However, the flowing water may at times carry resi-
dues to areas where their presence may be objectionable. While
reduction in residue levels varies with the canal and herbicide, many
residues are dissipated after a water flow of 10 to 15 miles. In most
cases, the dissipation can be attributed to dilution in water or absorp-
tion by bottom mud.
The concentrations of herbicides found in irrigation water are
unlikely to cause injury in crops. Crop tolerance studies showed that
crops can tolerate greater quantities of herbicides than would be
found in the water after applications for weed control. Where resi-
dues were found in crops following irrigation with water containing
herbicides, the levels were generally much lower than tolerances
already established for the same or similar crops.
REFERENCES
Aldhous, J. R. 1967. 2,4-D residues in water following aerial spray-
ing in a Scottish forest. Weed Res. 7:239-41.
Arle, H. F. 1950. The effect of aromatic solvents and other aquatic
herbicides on crop plants and animals. Proc. Western Weed
Control Conf. 12:58-60.
Arle, H. F., and McRae, G. N. 1959. Cotton tolerance to applications
of acrolein in irrigation water. Western Weed Control Conf.
Res. Progr. Rept., p. 72.
Averitt, W. K. 1967. Report on the persistence of 2,4-dichlorophen-
oxyacetic acid and its derivatives in surface waters when used to
control aquatic vegetation. Univ. of Southwestern Louisiana,
Lafayette. Unpublished.
Bartley, T. R. 1969. Copper residue on irrigation canal. Paper 98
presented at meeting of Weed Sci. Soc. Am., Feb. 11-13, Las
Vegas, Nev.
Battelle-Northwest Laboratories. 1966, 1967, 1968. Progress reports
on herbicide residues in irrigated crops. Unpublished.
Bruns, V. F. 1954. The response of certain crops to 2,4-dichloro-
phenoxyacetic acid in irrigation water. I. Red Mexican beans.
Weeds 3:359-76.
Bruns, V. F., and Clore, W. J. 1958. The response of certain crops
to 2,4-dichlorophenoxyacetic acid in irrigation water. II. Con-
cord grapes. Weeds 6:187—93.
Bruns, V. F., and Comes, R. D. 1966, 1967, 1968. Annual report of
weed investigations in aquatic and noncrop areas. USDA, ARS,
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208 / PART 3 / PESTICIDES AS WATER POLLUTANTS
Crops Res. Div. Unpublished.
Brims, V. F., Hodgson, J. M., Arle, H. F., and Timmons, F. L. 1955.
The use of aromatic solvents for control of submersed aquatic
weeds in irrigation channels. USDA Circular 971.
Bruns, V. F., Yeo, R.R., and Arle, H. F. 1964. Tolerance of certain
crops to several aquatic herbicides in irrigation water. USDA
Tech. Bull. 1299.
Coats, G. E., Funderburk, H. H., Lawrence, J. M., and Davis, D. E.
1966. Factors affecting persistence and inactivation of diquat
and paraquat. Weed Res. 6:58-66.
Cochrane, D. R., Pope, J. D., Jr., Nicholson, H. P., and Bailey, G. W.
1967. The persistence of silvex in water and hydrosoil. Water
Resources Res. 3:517-23.
Davis, E. A., Ingebo, P. A., and Pase, C. P. 1968. Effect of a water-
shed treatment with picloram on water quality. Forest Serv.
Res. Note RM-100. Fort Collins, Colo.: USDA.
Demint, R. J., Frank, P. A., and Comes, R. D. 1969. Amitrole resi-
dues and dissipation rate in irrigation water. Submitted for
publication.
Frank, P. A., and Comes, R. D. 1967. Herbicidal residues in pond
water and hydrosoil. Weeds 15:210—13.
Frank, P. A., and Demint, R. J. 1967, 1968. Annual report of weed
investigations. USDA, ARS. Unpublished.
Grzenda, A. R., Nicholson, H. P., and Cox, W. S. 1966. Persistence
of four herbicides in pond water. J. Am. Waterworks Assoc.
58:326-32.
Marston, R. B., Schults, D. W., Shiroyama, T., and Snyder, L. V.
1968. Amitrole concentrations in creek waters downstream
from an aerially sprayed watershed sub-basin. Pesticides
Monitoring]. 2:123-28.
Nelson, J. L., Bruns, V. F., Coutant, C. C., and Carlile, B. L. 1969.
Behavior and reactions of copper sulfate in an irrigation canal.
Pesticides Monitoring J. In press.
Norris, L. A., Newton, M., and Zavitkovski, J. 1967. Stream contam-
ination with amitrole from forest spray operations. Western
Weed Control Conf. Res. Progr. Rept. pp. 33-35.
Smith, G. E., and Isom, B. G. 1967. Investigations of effects of
large-scale applications of 2,4-D on aquatic fauna and water
quality. Pesticides Monitoring J. 1:16—21.
Stanford Research Institute. 1968, 1969. Progress reports on herbi-
cide residues in irrigated crops. Unpublished.
Timmons, F. L. 1960. Weed control in western irrigation and drain-
age systems. USDA, ARS 34-14.
. 1963. Herbicides in aquatic weed control. Proc. 16th South-
ern Weed Conf., pp. 5—14.
-. 1967. The waterweed nuisance. In U.S. Dept. of Agriculture
yearbook of agriculture, pp. 158-61.
Toth, S. J., and Riemer, D. N. 1968. Algae control in inland water.
Weeds Trees Turf 7:14-18.
U.S. Dept. of Agriculture. 1959, 1964. Agriculture census.
U.S. Dept. of Agriculture. 1969. Monitoring agricultural pesticide
residues 1965-1967. ARS Rept. 81-32.
U.S. Dept. of the Army. 1965. Expanded project for aquatic plant
control. House Document 251, 89th Congress, 1st Session.
Yeo, R. R. 1969. Dissipation of endothall in water and effects on
aquatic weeds and fish. Weed Science. In press.
-------
CHAPTER FOURTEEN.
PESTICIDES AND PEST MANAGEMENT
FOR MAXIMUM PRODUCTION AND
MINIMUM POLLUTION
DON C. PETERS
HE late Paul Errington, an ecologist in our department, once
said that the human mind craves constants but in biology deals with
variables. The words maximum and minimum both connote such rel-
ative value judgments. Furthermore, pesticide usage has been ac-
companied by certain ironies—controlling disease-carrying insects
has contributed to our population crisis, and while crop protection
has been a major factor in increased production, this has often been
followed by reduced prices. In an era when science and technology
are playing a major role in shaping our society, it is altogether too
easy for the individual scientist to lose his objectivity and assume
that his particular insights entitle him to become a demagogue. The
subject of pesticides has certainly lead to such polarity (Carson,
1962; Rudd, 1964; Egler, 1964a, 1964b; Whitten, 1966; McLean,
1967). The challenge today is for an enumeration of alternatives in
environmental management and an admission that with any strategy
there will be a certain amount of compromise. Pesticide usage con-
tinues to be confronted with the need for compromise. We may be
near the end of the golden age of agricultural pesticide technology
since there seems to be a geometric increase in regulations regarding
the chemical inputs for pest control. Wellman (1969) estimated that
the cost of developing a typical pesticide is now $4.1 million, up from
$2.5 million in 1964.
In an effort to facilitate your understanding of this area, I
would like to outline the pest management strategies available, relate
them to specific production commitments, and then consider the
ramifications to the role of agriculture in clean water. Consideration
needs to be given to both the quantity and quality aspects of this sub-
ject so that we can propose a rational compromise between pests and
pollution.
In entomology we often refer to pest population reductions which
occur without the influence of man as being natural controls. (The
DON C. PETERS is Professor, Department of Zoology and Entomology,
Iowa State University.
209
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210 / PART 3 / PESTICIDES AS WATER POLLUTANTS
term control has been overworked to include the agent, the action,
and the results.) Natural control can be subdivided into climatic,
edaphic, and biotic aspects. The reason for mentioning natural con-
trol is that we hope we can understand it and capitalize upon it as we
try to improve direct or applied pest control.
Modern agriculture is still largely dependent on proper climatic
conditions. The same sunlight, moisture, and nutrients are utilized
by weeds as well as planted crops. Crop adaptation is a matter of
growing the crop in an area where it has at least some competitive
advantages and applying additional controls as needed. Since each
organism has specific moisture, light, and temperature requisites, it
follows that pest species are not uniformly distributed and man can
capitalize on this knowledge. However, some diseases and insects may
be carried great distances by winds. The most dramatic illustration
of wind distribution would probably be the cereal rusts which have
been referred to as continental pathogens because they spread from
the subtropical regions to the north to cover the entire cereal acreages
in North America.
In nature, diversity appears to be a solution to catastrophic out-
breaks and destructive changes. Dasmann (1968) said that com-
plexity appears to be accompanied by stability and man seeks to
simplify the complex so that he can manage it. If a great variety of
plants are growing in an area, the chance of spread for a host-spe-
cific disease is greatly reduced. For this reason the chances for insect
and disease outbreaks are much greater in cultivated monocultures
than in natural areas. Under the conditions in northern forests, age
may act as diversity. As man has tried to manage forests and pre-
vent fires, he has occasionally allowed large areas with trees of the
same age to grow up. These may be attacked by insects or pathogens
which normally attack only a specific age category. When such at-
tacks occur the losses are more severe than would be true of a forest
with diverse age groups or species of trees.
I feel that a better understanding of the balance of nature is
needed for a meaningful communication of the science of pest con-
trol. "Key factor analysis" is a recent concept used by insect ecologists
such as Clark et al. (1967) in trying to characterize the major factors
contributing to population levels of insect groups. An extension of
this approach may be the reason why in each crop we have a few
major persistent pests, several species which become pests during
sporadic outbreak periods, and an additional group of potential pests
associated with a larger number of species which cause no damage
but occur in the area as scavengers or parasites and predators. The
interactions between these groups are frequently drawn in a web
configuration, but this may communicate a concept of peaceful coop-
eration whereas intense competition for resources is more in line with
the "key factor" approach. Work summarized in the National Acad-
emy of Science (NAS) publication on insects (1969) indicates that
food may be a key factor in regulating a pest, but that parasites and
predators, disease, weather, and migration have been found to be
key factors with as great a frequency. As an illustration, the Colorado
potato beetle in Canada was found to be limited by food. However,
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CHAPTER 14 / PESTICIDES AMD PEST MANAGEMENT / 211
I doubt that any potato farmer would consider it reasonable to allow
this vegetative feeder to completely devour the above-ground parts of
the plant before some direct means of control was sought.
It is my impression that similar relationships between crops and
pests exist in the realm of plant pathogens and to a different degree
in weed competition. I feel that the work of Kooper (1927) and Holm
(1969) relating to the competition between plants by growth inhibi-
tion of one species by another encourages speculation that if we knew
what inhibits some seed growth in the presence of other plants a
more effective weed control could be achieved. Species competition
should be managed for our good.
One other point I would like to emphasize before discussing ap-
plied controls is that when man put his hand to the plow and began
to modify plant diversity, he began a high-risk enterprise. There are
still no absolute measures of what is progress as far as manipulating
the disturbed cultivated environment. Many of us have gone along
with Swift's adage of the man "who can make two ears of corn or
blades of grass to grow where but one grew before," but I feel that
most thinking biologists today have conceded that man is not capable
of continuing to feed himself and his progeny unless he devises effec-
tive means of regulating his population. The question of the quality
of our environment is another thing that merits more attention.
APPLIED CONTROLS
Applied controls are those biological, cultural, legal, or chemical
practices which man utilizes in an effort to reduce losses caused by
pests. Each of these has its disadvantages and advantages and the
cost/benefit ratio needs to be continually investigated in a dynamic
agriculture and civilization. Paul Sears, in a recent visit to Iowa
State, warned that another danger in this scientific age was doing
things simply because they became technically feasible. For example
an insect-free cornfield may not be the most desirable condition. Let
us first consider biological control which may be either natural or
applied. Biological control probably has its main desirable aspects in
that it usually produces no side effects and frequently is a one-time
operation. Once it is set in motion there need not be an annual cost
for crop production. Biological control works best where some dam-
age can be incurred to the crop without serious economic loss and
where the soil is not disturbed. This means that we should look for
the most frequent successes in forest lands and in orchards, and the
least successes for biological control in the intensive cultivation prac-
tices of truck farming.
The three main aspects involved in the utilization of parasites
and predators are introduction, conservation, and augmentation.
While the introduction of an insect species for control of another in-
sect or weed is a complicated matter (NAS, 1968b), there have been
sufficient successes in this area, particularly in those instances where
the pest was not native, that continued work is certainly justified. It
has been estimated that if the program is effective, 80% of the intro-
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212 / PART 3 / PESTICIDES AS WATER POLLUTANTS
ductions are effective within three generations. By the conservation
of parasites and predators, I have reference to such situations as strip
mowing of alfalfa so that the shelter for predators is not completely
eliminated at any one time during the production period. The aug-
mentation of field populations by laboratory-reared parasites and
predators has met with varying success. It seems to show more
promise where the target insect infests a localized area and where
the parasites and predators are limited to the immediate area. I
know of no successful program of augmentation in the Upper Missis-
sippi Valley.
Insect pathologists have been working on diseases of insects for
over a hundred years, and a recent report (NAS, 1969) indicated that
there were 1,165 microorganisms which attacked insects. In this re-
gion disease agents have been used against the European corn borer
and Japanese beetles. However, there is a possibility of the insects
developing resistance to these diseases. A recent paper by Hoage and
Peters (1969) demonstrated the ability of honeybees to develop larval
resistance to American foulbrood disease. Similar disease resistance
probably occurs in nature as part of the overall web of competition
and survival of the fittest.
I have chosen only to mention and not discuss some other con-
cepts in biological control such as the areas of competitive displace-
ment, antimetabolites, feeding deterrents, or genetic regulation of
pests since these are still largely in the investigative stage and lack
working field programs to confirm their potential.
Host-plant resistance is frequently considered as a part of the
biological control approach and certainly it is a modification of the
host organism in an effort to reduce losses from pest infestations. It
is doubtful if we would be able to continue cultivation of any of the
cereal crops without disease-resistant cultivars. And yet in the case of
the cereal rusts, we are probably witnessing evolution working at an
extremely rapid and efficient rate but not toward our varietal improve-
ment goals. Van der Plank (1968) is optimistic and states that crop
breeders should continue their work on developing disease-resistant
lines.
By contrast to the great number of disease races that have
cropped up in relation to varietal resistance, the story on insect-
resistant crops is not nearly so complex. Three exceptions are the
corn leaf aphid and pea aphid races or "biotypes" reported by Carrier
and Painter (1956) and Carrier et al. (1965) and the Hessian fly
where there are currently at least four races (Gallun et al., 1961).
Host-plant resistance is probably the most ideal means of controlling
the major disease and insect pests of the major crops. Development
of resistant varieties does entail a considerable expenditure of time
and the cooperative effort of a team of investigators and therefore
will probably be limited to only the major pests of the various cul-
tivated crops. The potential for breeding insect- and disease-resistant
animals is certainly not great. I have no idea of how one would go
about breeding a corn plant for resistance to foxtail competition. All
of the biological control approaches require a lot of specific research
before they can be utilized.
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CHAPTER 14 / PESTICIDES AND PEST MANAGEMENT / 213
Cultural pest control is among the oldest of man's practices in
trying to come to grips with his pests. Sanitation as illustrated by
crop residue destruction and animal waste removal is an important
means in reducing the breeding potential of a number of pests. Till-
age practices can have an impact on any of the three pest groups that
we have been considering. By way of illustration, it is hard to say
whether the Iowa farmer should plow his cornstalks under to control
European corn borers, weeds, or the yellow leaf blight disease. Re-
duced tillage may encourage some pest species, but increased tillage
will also destroy many of the organisms that would tend to afford a
competitive balance between the organisms in the field.
The economics of current production practices in the Corn Belt
leave little leeway for pest management in timing the planting opera-
tion or the intensity of fertilization. Since both of these need to be
maximized from an agronomic standpoint, workers in pest manage-
ment are confronted with the need to devise some means of compen-
sating for agronomic practices which may be at odds with optimum
pest control. Early harvesting can certainly help to avert some of the
potential losses that might otherwise be attributed to stalk-attacking
insects or diseases.
Physical or mechanical controls are seldom of importance in the
large acreages of cultivated crops common in modern agriculture, but
such things as the flaming of alfalfa fields may reduce the alfalfa
weevil threat and give some reduction in the chickweed problem as
well.
Another illustration of mechanical means is the light trap. As
far as reducing crop pests, light traps have been of limited value, with
the most favorable data coming from the tobacco-growing area in
North Carolina (Lawson et al., 1966). There is also a report of re-
duction in Heliothis spp. as cotton pests in Texas, following the use
of artificial light (Nemec, 1969).
Insect sterilization has received a lot of popular publicity in the
past 10 years because of the success of the screw worm program in
southeastern United States (Bushland et al., 1958) and more recently
in the Texas area. However, there are several drawbacks to this ap-
proach. It is extremely expensive in comparison to other programs
with which entomologists have been associated. Sterilization would
not appear to be practical where a pest overwinters in an extensive
area or where numbers are not severely reduced in the spring. Chemo-
sterilants have been and are being investigated but in the past decade
they have not proved to be commercially acceptable in even a single
field program in the United States.
The potential use of attractants and repellents still must be con-
sidered nebulous, although there have been some excellent results
where attractants and insecticides were combined on island situations
in eradication programs (Beroza, 1966). Personally, I have serious
reservations about man's ability to totally eradicate any insect pest
species from the continents. Eradication of weeds and diseases is
even less likly (NAS, 1968a).
Chemical control of pests is an old practice. It probably began
when the Arabians discovered the benefits of sulfur for louse control
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214 / PART 3 / PESTICIDES AS WATER POLLUTANTS
for their horses or with the early observations of the herbicidal effects
of salt water. It has only been during the last 40 years that man has
begun to synthesize chemicals rather than to depend upon those
which he could obtain by mining or refining. The intensity to which
he has used these synthesized products has had a considerable in-
fluence in the gains in production potential on a number of crops as
illustrated in a paper by Decker (1964). I have tried to update these
production figures in Table 14.1. Insecticide use on oats, hay, and
soybeans has been low. For oats and hay the returns have been low
but the per acre net return from soybeans has been almost as good as
corn. The relative increases in per acre yields for corn, cotton, and
potatoes since the advent of DDT and other organic insecticides has
been much greater than for oats, hay, or soybeans. I certainly do not
believe that the yield increases are entirely caused by insect control,
but the insecticides must obviously be aiding a total production pro-
gram. There may also have been a profit differential that justified the
decision to use the chemicals at the time the first synthetic pesticides
were applied. The economics of production would appear to continue
to dictate similar pesticide use patterns.
The hope held out for growth-regulating hormones as "third
generation insecticides" by Williams (1967) may be only a hope, and
certainly many of us will need to change our attitude about taxes if
these hormonal mimics are to be used. I doubt whether industry will
be willing to expend the resources necessary to develop these specific
means of control. I would expect the financial returns to be consider-
ably less favorable than with the conventional multi-use pesticides
available today. Persing (1965) wrote that if DDT were specific for
houseflies, its profits would not have equaled research and develop-
ment costs. I have heard a lot of talk to the contrary, but specific
pesticides have not been forthcoming in the past decade. A good
demonstration of the problem is a product by the name of Manazon
which is excellent for aphid control but apparently the company own-
ing this product does not feel that it would be a profitable product to
develop at this time. By contrast, the top ten pesticides in 1967 sales
were all broad-spectrum materials (Mahan et al., 1968).
There are certainly many pitfalls that can arise from over-
dependence on use of chemicals in crop production. Smith (1967,
1969a, 1969b) has done an excellent job of describing some such
problems in cotton production and he also tells of the potential in-
tegrated control has as a means of maximizing the effectiveness of
chemical applications. As Mills (1968) indicated, we need to continue
to sharpen our entomological knowledge of space and time in insecti-
cide applications. Knipling (1966) has calculated that 1 Ib of the
most effective boll weevil insecticide would be enough to kill all the
boll weevils in the United States if applied topically in the spring
when weevil levels are lowest.
These are the pest control alternatives available. The next ques-
tion is, How and to what extent are these being used in various pro-
duction programs?
-------
TABLE 14.1. Average yields for selected crops in 48 states.
Crop
Oats
Ratio*
Hay
Ratio
Soybeans . . .
Ratio
Corn
Ratio
Cotton
Ratio
Potatoes
Ratio
Percent
Acres
Treated
in 1966
1
3
4
33
54
89
1901-40
29.4
1.81
26.0
186.0
63.0
1941-45
32.2
1.10
1.36
0.75
18.5
33.1
1.27
262.0
1.41
85.0
1.35
Yield per
1946-50
33.9
1.15
1.35
0.75
20.4
1.11
37.0
1.42
273.0
1.47
132.0
2.09
Acre for Yea
1951-55
34.6
1.18
1.46
0.81
20.0
1.08
40.2
1.54
326.0
1.76
153.0
2.43
rs Indicated
1956-60
39.7
1.35
1.66
0.92
23.2
1.26
51.2
1.97
434.0
2.34
183.0
2.90
1961-65
45.1
1.54
1.76
0.97
24.2
1.31
65.9
2.53
492.0
2.65
196.0
3.12
1966-68
49.2 bu.
1.68
1.94 tons
1.07
25.5 bu.
1.38
76.5 bu.
2.94
479.0 lb.
2.58
211.0 cwt.
3.35
* Ratio of production in each period to production from 1901 to 1940, except in soybeans where ratio base used was
1941-45.
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216 / PART 3 / PESTICIDES AS WATER POLLUTANTS
PEST MANAGEMENT IN THE SEVERAL AREAS OF PRODUCTION
There are a number of functional considerations or variants in-
volved in considering the pest problems as related to the food, shelter,
and clothing areas of production. There is also a need to keep in
mind the "aesthetic needs" of man. How many "Madison Avenue"-
gendered needs can we afford on our crowded planet?
In the area of food production, the cereal crops and potatoes are
the major carbohydrate sources. In the United States, the percentage
of cereal crops receiving insecticide treatment in 1964 was around
3% for small grains, but about 33% for corn, of which a large per-
centage was for soil insect control. According to Fox et al. (1968)
chemicals for disease control were used on less than 0.5% of the
acres on all of these crops, while herbicides were used on 57% of the
corn acres and about 30% of the acres planted to the other grain
crops.
The amount of money spent on livestock pest control, according
to Gale et al. (1968), was less than 5% of the total farm use, and the
estimated pounds of insecticide were an even smaller ratio. In spite
of this relatively small volume, the point source principle used in
identifying and detecting pollution may present problems for pesti-
cide usage on livestock and poultry. However, the major problem is
from misuse or contamination, since there is little likelihood of water
contamination from the materials used in fly control today.
Production of fruits and vegetables is the most intensive high-
value crop production program, but as pointed out previously there is
a considerably greater potential for biological strategies to effectively
control orchard pests as compared to truck farming operations. In
1966 Fox et al. (1968) found that 28% of the vegetable acres in the
48 contiguous states were treated with a herbicide, whereas the per-
centage of apple acres treated was 16% , and that for other deciduous
fruits was only 13% . Similar figures on insecticides indicate that use
on vegetables was 56% , on apples 92% , and on other deciduous
fruits 72% . Apparently, the consumer insistence on perfect fruit has
encouraged a lot of spraying. While Irish potatoes would normally be
considered a carbohydrate source, the percentage of crop acres on
which insecticides were used was 89% over the contiguous states, but
reached 100% in the southeastern and southern plains states. The
demand for fruits and vegetables free of insect damage has certainly
been met with an intensive use of pesticides. With current harvesting
and processing it is doubtful if this usage can be changed.
Turning to clothing, I have already indicated that a very small
percentage of the total amount of pesticides is used on livestock and
as one would expect the amount of pesticides used in wool production
would be minimal. By contrast the proportion of herbicide and in-
secticide usage in cotton production would be far greater than that
for other field crops with the exception of tobacco and potatoes. Ac-
cording to Gale et al. (1968), in 1964 the United States average per
acre pesticide expenditure was $11.27 for cotton compared to only
Si.87 per acre of corn. This illustrates the deceptive potential of
figures since there were 66 million acres of corn as compared to 14
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CHAPTER 14 / PESTICIDES AND PEST MANAGEMENT / 217
million acres of cotton. Therefore the total expenditure for cotton
was only 20% greater than for corn pesticides. In another sense
pesticide use on cotton is much more intensive and does not allow for
as great a dilution as it enters the environment.
The current trend is toward more synthetic fibers. There are
some indications that these too may possibly have some harmful side
effects. Determining the long-term influences of these products on
experimental animals should be pursued with the same rigor as has
the toxicology of chemical control agents.
Man's need for shelter is influenced by diseases and insects only
to the extent that he utilizes wood in providing these shelters. The
critical times for timber seem to be during the establishment of the
young trees, as the standing crop nears harvest, during the processing
period, and after the structure has been completed, when termite and
decay problems may arise. Economics of lumber production are such
that it has not been feasible to treat large acreages repeatedly. Conse-
quently current estimates are that less than 5% of our forest lands
have ever been sprayed with any insecticides. The hazard is that
when forest areas are sprayed it is usually done in large contiguous
blocks treated as part of a federally coordinated program. Such mas-
sive programs usually involve large aircraft in terrain where it is not
expedient to avoid spraying of streams and other areas where fish and
wildlife are concentrated. Therefore, while the direct problems of
chemical treatment to the wood are nil, the ramifications to the fish
and wildlife populations may be considerable, since the only logical
places for significant wildlife populations are in the forests and
ranges of the United States.
I would like to consider the aesthetic ramifications associated
with agricultural production. One concern is with the farm fence
row. To many people the uniform growth of grasses which can be
achieved by annual 2,4-D spraying is desirable. Others like a diver-
sity in plants and do not find this uniform grass population appealing.
It is certainly true that this is a more costly practice than allowing the
plants to grow as they wish. It is difficult to extrapolate Scott's (1938)
data to modern times with increased miles traveled on our primary
and secondary roads, but it is time we determine if wildlife would
increase if ditches and roadsides were left to grow up in a natural
vegetation as game cover.
Most of us became too embroiled in the Dutch elm disease con-
trol program to consider it with much objectivity. While this has
basically been an urban rather than a rural problem, I believe that
there are lessons to be learned from the successes and failures of
various strategies and tactics tried in controlling this pest. The Iowa
Cooperative Extension Service (1961) outlined a 4-step program of
(1) evaluation and education, (2) sanitation, (3) maintenance, and
(4) spraying. Steps 1 through 3 were seldom executed effectively, but
the extension entomologists were certainly blamed for any robins that
died after DDT spraying. All phases of agriculture must get involved
in public information and communication.
Home gardens, lawns, and flowers are not usually considered an
agricultural problem and yet in the area of pesticide pollution they
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218 / PART 3 / PESTICIDES AS WATER POUUTANTS
should not be overlooked. I submit that there is as great a probability
that the suburbanite will dump the leftover spray into the sewer as
there is that the agriculturalist will dispose of his leftover pesticides
in such a manner as to directly contaminate water sources. When one
considers the population ratio between rural and suburban peoples in
the United States today, the magnitude of this problem becomes
obvious.
ROLE OF AGRICULTURAL PESTICIDE IN CLEAN WATER
What then are the ramifications of pest management to agricul-
tural waters? If we assume that changes will be brought about by
the due process of legislation and education I think we can make
some fairly good assumptions and suggestions as to what can be done
to educate ourselves about the proper use of pesticides in farm pro-
duction programs. Figures 14.1 and 14.2 on land uses and relative
intensity of pesticide use on crops in the United States should put
the problem in perspective. First let us consider small grain produc-
tion. With the present net return from these crops, it is doubtful
whether additional chemicals will be used in an effort to achieve more
efficient production. These crops are grown on relatively large
acreages and there is little likelihood that yield can be increased with-
out the addition of irrigation. Cultural practices and host plant re-
sistance should continue to be mainstays of pest control on small
grains.
After visiting with agronomists, agricultural engineers, and
others interested in corn production, I believe that future corn pro-
duction will see increased emphasis on narrow row spacing with a
moderating trend in the immediate future to 30-inch row spacing.
Even the shift to 30-inch row spacing means essentially a 30% in-
crease in insecticide usage to achieve the same amount of rootworm
protection as compared to 40-inch row spacing. To partially offset
this we have been working (Peters, 1965; Munson et al., 1970) to try
to combine one chemical treatment for both corn rootworms and Eu-
ropean corn borer control. Some of the current insecticides under in-
vestigation might control com leaf aphids also, and thereby get three
birds with one stone. The emphasis on minimum tillage will need to
be watched and possibly modified in the future in line -with efficient
FIG. 14.1. Primary land
use, 1964. i °r*e£^\i PASTURE
L —^^ & RAN,GE
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CHAPTER 14 / PESTICIDES AND PEST MANAGEMENT / 219
FIG. 14.2. Insecticide use
33^ \ / on U.S. crops, 1964. Insec-
CCR\Y \ / ticides were applied on
„, ' *LCHE' BEETS 52% of the small grain
/o —OTHER _ ., . =
J FIELD CROPS acreage. Small grains were
grown on more acres than
any other crop.
use of herbicides and insecticides. Disease problems may become
greater if crop residue is left on the soil surface. The ideal system for
corn would be to maintain the intertillage system so that the space
between the row need not be treated with pesticide.
We have been searching for a replacement for aldrin and hepta-
chlor, the two major chlorinated hydrocarbons still used in corn in-
sect control. To date we have not found a product that will control
white grubs, wireworms, or cutworms at economically feasible rates.
The carryover problem of herbicides is one reason given for planting
corn after corn. This means that the use of persistent herbicides has
intensified the need for corn rootworm control measures since corn
rootworms do economic damage mainly in fields of corn following
corn. If this situation can be alleviated we would hope that the acres
treated for corn rootworms can be stabilized or even reduced. How-
ever, it is possible that with a major change in crop sequence patterns
other insect pest problems may increase in importance; Cole (1966)
has pointed out that all communities harbor opportunistic species.
The disease problem seems to be increasing under higher plant popu-
lations. Some promising disease control chemicals are being eval-
uated but the potential economics of such pesticide usage has not
been worked out.
At the risk of sounding provincial, I would like to emphasize that
soybeans should be grown in the northern part of the United States
rather than as a replacement for cotton. In the South chemicals will
have to be used to control corn earworms, stink bugs, and other insect
pests of soybeans, whereas these insects have not occurred in damag-
ing numbers in soybean culture in the Upper Mississippi Valley. I feel
that this is a place where timely legislative action could reduce the
overall pesticide burden in the United States.
Cotton culture is an enigma for it is profitable under the present
allotment system to use relatively large quantities of pesticides to
maximize yield on a per acre basis. If allotment were on a basis of
pounds of lint cotton per farm unit it might be possible to reduce
pesticides. Another consideration might be the emphasis of produc-
tion on those areas where cotton pests are less of a problem. Addi-
tional irony in this situation is that while Smith (1969b) and his
associates in California have done an excellent job of describing in-
tegrated control to the scientific community, the amount of pesticide
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220 / PART 3 / PESTICIDES AS WATER POLLUTANTS
money spent per acre of cotton production in California was higher in
1966 than any other area of the country. It is hoped that the Califor-
nia entomologists can devise as efficient a means of communicating to
the growers in the state as they have to the scientific community.
There is still a demand for tobacco products. This high intensity
crop will probably continue to utilize large amounts of pesticides in
localized areas. If hopes are realized, continued work on mechanical
or biological controls can reduce the insecticide usage for this crop.
While the total tonnage of pesticide used may be small, the likelihood
of local stream or pond contamination is still very real. Potatoes and
sugar beets also present a. problem since the net return to the grower
is very small unless a high yield per acre can be achieved. Therefore,
we again have the potential of a point source contamination situa-
tion. Since these crops are grown by relatively few farmers it should
be possible to amplify the educational effort toward the reduction of
unnecessary treatments or low return treatment.
The juxtaposition of metropolitan areas and intensive truck
farming will continue to be the cause of friction in pesticide usage.
The high value commodities would seem to justify the use of pesti-
cides in order to insure a favorable return to the grower; however, the
chance of water contamination is a continuing problem when such
usage is adjacent to streams, ponds, and lakes with high recreational
demand.
Every effort should be made to encourage fruit growers to in-
vestigate the feasibility of enhanced biological control in their or-
chards. An important corollary for such a program to be completely
successful is that we will also need to educate the consumer to accept
less than perfect produce.
There is currently a boom in large feedlot operations in the
southwestern states of Texas, Oklahoma, Kansas, and Colorado. This
has been brought about, in part, by increased irrigation of sorghum
and corn as a grain source for livestock feed. These lots tend to be
large and the livestock are confined. If we continue to emphasize
that "the solution to pollution is dilution" then this is a step in the
wrong direction. It is true that these are areas where the moisture
problems in feedlots are reduced, but if pesticides are needed to con-
trol flies and other insect problems under the crowded livestock con-
dition, it is only conjectural as to what would be the concentration of
insecticide in the small amount of runoff that might occur from
these areas.
If we really feel that the chlorinated hydrocarbons are a detri-
ment to our society, we should encourage an immediate ban on all
small-package registrations of these products. This is an area in
which misuse is most likely to occur since the homeowner-gardener is
not confronted with the cost/return ratio to the extent that people in
crop production are.
I feel that I must take a stand in opposition to many of the large
federal insecticide pest control programs. These have been subject
to considerable criticism, for even though they achieve a major cost
reduction per treated unit, the tendency, as pointed out by Cope and
Springer (1958), is that by achieving these efficiencies in distribution
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CHAPTER 14 / PESTICIDES AND PEST MANAGEMENT / 221
there is a comparative loss in target precision and effectiveness. I
believe the Plant Pest Control Division would do well to continue its
emphasis on the distribution of biological control agents or at-
tractants. The substitution of Mirex bait in the fire-ant program was
certainly a progressive step in the right direction.
In summary, I would say that the various agencies in pest con-
trol have been and continue to be concerned about the use of pesti-
cides in relation to the total environment. We are working and will
continue to work to the limit of personnel and funds available. The
need for increased funds in the future is great since the newer
strategies are of a nature that will require public support for their
application. Recently a national joint task force on pollution proposed
less than a 1% increase in effort for the pesticide area for the next
decade! If the public demand for sophistication in pest control is to
be achieved, more imaginative research support will have to be found.
Man is the dominant species on earth today and the question is not if
he will modify the environment, but the question is how can he
modify the environment in such a way as to achieve a stability which
will allow his long-term existence.
Starr's (1969) article on social benefits versus technological risk
merits careful consideration. In order to maximize pest management
for maximum production, crop protectionists should expect a reason-
able risk ratio along with other agricultural, industrial, and urban
sources of water pollution. The alternative loss of 10 to 30% of our
basic agricultural production to pests and diseases needs to be held
before the consuming public.
REFERENCES
Beroza, Morton. 1966. The future role of natural and synthetic at-
tractants for pest control in pest control by chemical, biological,
genetic, and physical means. USDA, ARS.
Bushland, R. C., Knipling, E. F., and Lindquist, A. W. 1958. Eradi-
cation of the screw-worm fly by releasing gamma-ray sterilized
males among the natural population. Proc. Intern. Conf. Peace-
ful Use Atomic Energy Geneva 12:216-20.
Carson, Rachel. 1962. Silent spring. Boston: Houghton Mifflin.
Cartier, J. J., and Painter, R. H. 1956. Differential reactions of two
biotypes of the corn leaf aphid to resistant and susceptible
varieties, hybrids and selections of sorghums. /. Econ. Entomol.
49:498-508.
Cartier, J. J., Isaak, A., Painter, R. H., and Sorensen, E. L. 1965.
Biotypes of pea aphid Acythosiphon pisum (Harris) in relation
to alfalfa clones. Can. Entomol. 97:754-60.
Clark, L. R., Geier, P. W., Hughes, R. D., and Morris, R. F. 1967.
The ecology of insect populations in theory and practice. Lon-
don: Methuen.
Cole, Lament C. 1966. The complexity of pest control in the environ-
ment. In Scientific aspects of pest control, pp. 13-25. Nat.
Acad. Sci., Nat. Res. Council Publ. 1402, Wash., D.C.
Cooperative Extension Service. 1961. Diseases and insects attacking
Iowa elms. Iowa State Univ. Pamphlet 250 (Rev.)
-------
222 / PART 3 / PESTICIDES AS WATER POLLUTANTS
Cope, O. B., and Springer, P. F. 1958. Mass control of insects: the
effects on fish and wildlife. Entomol. Soc. Am. Bull. 4:52-56.
Dasmann, R. F. 1968. Environmental conservation. 2nd ed. New
York: John Wiley.
Decker, George C. 1964. The past is prologue. Entomol. Soc. Am.
Bull. 10:8-15.
Egler, F. E. 1964a, Pesticides in our ecosystem. Am. Scientist
52(1): 110-36.
. 1964b. Pesticides in our ecosystem: communication. II.
BioScience 14 (11): 29-36.
Fox, Austin, Eichers, T., Andrilenas, P., Jenkins, R., and Blake, H.
1968. Extent of farm pesticide use on crops in 1966. USDA,
Agr. Econ. Rept. 147.
Gale, J. F., Andrilenas, P., and Fox, A. 1968. Farmers' pesticide ex-
penditures for crops, livestock, and other selected uses in 1964.
USDA, Agr. Econ. Rept. 147.
Gallun, R. L., Deay, H. O., and Cartwright, W. B. 1961. Four races
of Hessian fly selected and developed from an Indiana popula-
tion. Purdue Univ. Res. Bull. 732.
Hoage, T. R., and Peters, D. C. 1969. Selection for American foul-
brood resistance in larval honey bees. /. Econ. Entomol. 62:
896-900.
Holm, LeRoy. 1969. Chemical interactions between plants on agri-
cultural lands. Doivn Earth 25:16-22.
Knipling, E. F. 1966. New horizons and the outlook for pest control.
In Scientific aspects of pest control, pp. 455-70. Nat. Acad. Sci.,
Nat. Res. Council Publ. 1402. Wash., D.C.
. 1968. The role of chemicals in the general insect control
picture. Entomol. Soc. Am. Bull. 14:102-7.
Kooper, W. J. C. 1927. Sociological and ecological studies on weed
vegetation of Pasurian. Rec. Trav. Bot. Neerl. 24:1-255.
Lawson, F. R., Gentry, C. R., and Stanley, J. M. 1966. Experiments
on the control of insect populations with light traps in pest
control by chemical, biological, genetic, and physical means.
USDA, ARS.
McLean, L. A. 1967. Pesticides and the environment. BioScience
17:613-17.
Mahan, J. N., Fowler, D. L., and Shepard, H. H. 1968. The pesti-
cide revieiu 1968. USDA, Agr. Stabilization and Conserv. Serv.
Mills, H. B. 1968. Summary and conclusions in Symp. on the
Science and Technology of Residual Insecticides in Food Pro-
duction with Special Reference to Aldrin and Dieldrin. Shell
Oil Co.
Munson, R. E., Brindley, T. A., Peters, D. C., and Lovely, W. G. 1970.
Control of both the European corn borer and corn rootworms
with one application of insecticide. Submitted to J. Econ.
Entomol.
National Academy of Sciences. 1968a. Plant-disease development
and control. Principles of plant and animal pest control. Vol. 1.
. 1968b. Weed control. Principles of plant and animal pest
control. Vol. 2.
1969. Insect-pest management and control. Principles of
plant and animal pest control. Vol. 3.
Nemec, S. J. 1969. Use of artificial lighting to reduce Heliothis spp.
populations in cotton fields. /. Econ. Entomol. 62:1138-40.
Persing, C. O. 1965. Problems in the development of tailor-made
-------
CHAPTER 14 / PiSTICiDSS AND PEST MANAGEMENT / 223
insecticides, specific insecticides. Entomol. Soc. Am. Bull.
11:72-74.
Peters, D. C. 1965. Chemical control of resistant corn rootworms
in Iowa. Entomol Soc. Am. Bull. 20:58-61.
Rudd, R. 1964. Pesticides and the living landscape. Madison: Univ.
of Wis. Press.
Scott, T. G. 1938. Wildlife mortality on Iowa highways. Am. Mid-
land Naturalist 20:527-39.
Smith, R. F. 1967. Principles of measurements of crop losses caused
by insects. FAO Symp. on Crop Losses, Rome, 2-6 Oct. 1967,
pp. 205-24.
. 1969a. The importance of economic injury levels in the de-
velopment of integrated pest control programs. Qualitas Plant.
Mater. Vegetables 17:81-92.
. 1969b. Patterns of crop protection in cotton ecosystems.
Mimeo of talk given at Cotton Symp. on Insect and Mite Control
Problems and Res. in Calif., 12-13 March 1969, Hotel Clare-
mont, Berkeley, Calif.
Starr, Chauncey. 1969. Social benefits versus technological risk.
Science 165:1232-38.
Tukey, John W., chairman. 1965. Restoring the quality of our en-
vironment. Report of the Environmental Pollution Panel of
President's Science Advisory Committee.
U.S. Dept. of Agriculture. 1966a. Field crops by states, 1959-64.
Statistical Bull. 384.
. 1966b. A century of agriculture in charts and tables. Agri-
culture Handbook 318.
Van der Plank, J. E. 1968. Disease resistance in plants. New York
and London: Academic Press.
Wellman, Richard H. 1969. Ag chemicals industry faces big
changes. Chem. Eng. News, pp. 22-23.
Whitten, J. L. 1966. That we may live. Princeton, N. J.: D. Van
Nostrand.
Williams, Carroll M. 1967. Third-generation pesticides. Scientific
Am. 217:13-17.
-------
CHAPTER FIFTEEN^
WORKSHOP SESSION
DON C. PETERS, Leader
H. B. PETTY, Reporter
I HE general public at present suffers from lack of factual
and realistic information pertaining to (1) the real role and impor-
tance of pesticides in food production, (2) the present restrictive
regulations which govern labeling, sale, and use of pesticides, (3)
the accident-safety record of pesticide use, and (4) the food-monitor-
ing work of the HEW, FDA, which so carefully protects our food
supply from any contamination that could be considered deleterious.
The general public is unaware of extensive use-education programs
and they have the opportunity to read only the overpublicized alarm
stories, many of which are not realistic. There is a need, therefore,
for the Cooperative Extension Services to expand their programs to
include more than just agriculture.
PESTICIDES AND CLEAN WATER
Those interested in clean water and pesticides must realize that
as long as chemical tests in parts per trillion can be made, trace
amounts of the pesticides or their metabolites will at some stage be
found in water. Thus, permissible levels in water must be estab-
lished if we are to continue use of any pesticides. Such levels might
be established only for drinking water, or they might include marine
waters, irrigation waters, or waters for swimming, boating, and fish-
ing. It would be possible to consider overall environmental permis-
sible levels or international permissible levels. It would be impos-
sible to set levels defined by (1) the lowest level of testing accuracy
and (2) the level at which it could be guaranteed that there was not,
nor ever would be, any deleterious effects of any kind.
Aquatic herbicides, to be effective, are applied to water or im-
mediately adjacent to water. There are at present very few toler-
ances established for these aquatic herbicides in water. Some older
ones such as arsenic do have established levels. Tolerances have
been established for food crops for the "newer" herbicides but not
DON C. PETERS is Professor, Department of Zoology and Entomology,
Iowa State University. H. B. PETTY is Professor and Extension Ento-
mologist, University of Illinois.
224
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CHAPTER 15 / WORKSHOP SESSION / 225
for water. It is imperative that permissible levels be established soon.
Chlorinated hydrocarbon insecticides present a different prob-
lem. Some people believe that permissible levels in water can be set,
others do not. Although the hydrocarbons are occasionally applied
directly to water, their appearance in water usually results from a
nonwater use. This can be runoff from actual use, but it can also
be manufacturing waste. These insecticides are not water soluble
and escape from it at every opportunity; thus they accumulate on
the aquatic plants and bottom sediment where so many of our
aquatic organisms live. The organisms concentrate these chemicals
in their bodies, sometimes to thousands of times the amount in
the water.
All chlorinated hydrocarbons accumulate in living organisms
in varying degrees. Of the many, only a few present problems.
Dieldrin probably persists in the environment longer than others,
although DDT approaches it in persistence. Dieldrin content in
fish is in relation to water content, not food content. When fish are
fed excessive amounts of dieldrin there is a quick uptake, but the
body content returns to the water-dieldrin eouilibrium within a
month. This is the opposite to DDT. Although DDT and its metabo-
lites stay in the environment, DDT is apparently responsible for the
upset in the calcium metabolism in some birds. Endrin, with the
highest acute toxicity, does not persist as long as the other two and
organisms cleanse themselves of endrin readily. Endrin is, at the
moment, suspected of svstemic absorption.
Although it is difficult to set permissible levels for chlorinated
hydrocarbons for all situations, levels have been set for drinking
water. As a result of a committee of about 50 experts pooling their
knowledge, in Mav 1968 the Water Pollution Control Administration
published "Water Quality Criteria."
It is possible to set permissible levels for the organophosphates
since the amount which will produce cholinesterase inhibition can be
defined with some accuracy. As much as 10% inhibition may be
permissible. Furthermore, the residues of organic phosphates in
water are short-lived and runoff from agricultural use, if found at
all, is present for a very short time. Manufacturing wastes rmy be
more important than use runoff. However, one point to be considered
is the speed of reversibility of phosphate effect (comparativelv low)
and carbamate effect (comparatively high) on cholinesterase levels.
Manufacture of these products provides another avenue for
contamination. There are examples where waste from pesticide man-
ufactrring plants seriously contaminated miles of streams. A per-
missible level for these products in factory effluent must also be set.
PESTICIDES AND THEIR METABOLITES
Knowledge of the metabolism of barbiturates 15 years ago has
been greatly enlarged upon and even changed. The same thing is
happening with pesticides. DDT is not a single compound but a
mixture of many materials. Recently in vivo isomerizations have
been authentically reported in feeding experiments in which o,p'-DDT
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226 / PART 3 / PESTICIDES AS WATER POLLUTANTS
was fed and p,p'-DDT was formed in the animal. Similarly, p,p'-DDT
was fed and o,p'-DDT was formed in the animal. It has also been
published in Science that o,p'-DDT has pronounced estrogenic effects.
Reference has been made to the absence or the quick disap-
pearance of organophosphates. Do we know the metabolites of
phorate, Dyfonate, carbofuran, etc.? How about amino parathion
and its effects? In short, we need to know more about the biological
effects of pesticide metabolites than we do at present. A small amount
of a toxic chemical can be tolerated by most organisms. A person can
ingest a very low level of parathion and be unable to detect a reac-
tion, except through very rapid sampling, as parathion is detoxified
rather quickly. But with an increase in this level of intake, one soon
starts detecting it or some of its metabolites. A little more and
symptoms of intoxication are evident.
Is it possible to determine the no-effect level for pesticides and
their metabolites for the most important sensitive species of animals?
It might be man, the peregrine falcon, or others, but we could estab-
lish a base line. We will have to settle on the most toxic form of a
given chemical as well as the most sensitive species. In the case of
DDT is it the p,p'-isomer, the o,p'-isomer, DDE, or possibly DDD?
What is the important sensitive species for which we can determine
an environmental level for any given pesticide? Is this level con-
sistent with its use in agriculture and public health? Is this kind
of approach a practical one? What is best for our human society?
These were some of the unanswered questions concerning pesticides
and the quality of our environment.
ROLE OF PESTICIDES
Pesticides protect plants and animals from pest losses to the
benefit of mankind. This should be done so as not to harm man now
or in the future. However, no scientist ever could or would positively
guarantee that no harm could ever occur from the use of a certain
chemical. To answer every question that could be posed would
require 30 years of search for answers, and such detail, if not scien-
tifically impossible, is financially impossible.
Without pesticides, food production would be reduced some
40 to 50%, and the quality would be greatly reduced. Bread as we
know it would still be present but would contain insect fragments
and some rodent excrement. Today food processors are on the horns
of a dilemma—foods are inspected for both insect fragments and
pesticide, and an entire day's pack can be confiscated if contamina-
tion (by either) is found in any one can or case of processed food.
In the past, tolerances were established for chemicals on food
crops. The safety factor was considered to be 100 to 1. That concept
is no longer valid. We are now searching for minor or hidden effects.
We have searched for flaws in DDT for some 25 years and can still
find a few weaknesses. The Russians are interested in carbamates
and are diligently searching for hazards. We constantly search for
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CHAPTER 15 / WORKSHOP SESSION / 227
metabolites, side effects, etc. In the meantime, we have constant
pleas for help to control pests in order to enhance food supplies.
PESTICIDES AND THE GENERAL ENVIRONMENT
Little can be learned about pesticide contamination until the
materials are used in our environment. Mock environments can be
assembled, but based only on our past experience with DDT and
other chlorinated hydrocarbons. Had it not been for widespread
use of these materials it is doubtful that we would have been able to
foresee and prevent any of our present-day problems. We can
theorize, but until we use a chemical and find it in streams, for
example, we do not know the actual environmental problems in-
volved.
As greater chemical detection finesse is attained we change our
views about residues. The one philosophy that might be acceptable
is the one used by the USDA in clearing labels—if you can use an
insecticide in such a way as to avoid having a residue, then there
should be no permissible level.
Coho salmon survival from eggs from Lake Michigan was lower
than from eggs from Lake Superior. It seems that more information
is needed on this entire situation.
GENERAL COMMENTS
We too often view insecticides as though a single one will be
with us for a lifetime. Actually, DDT lasted about 10 to 15 years,
others a shorter time. The commercial life of an insecticide is a
matter of years, not decades, so the time to find the answer to the
questions is limited. Resistance of insects to an insecticide can
develop rapidly and a product can be on the market and gone before
problems even arise. Insecticides of the future will have a short
commercial life, not a long one.
We have alarmed people who now want to do something about
pollution, including pesticides, and we are in no position to answer
all the questions and supply the guidance needed. We need much
more research which will cost taxpayers large sums of money if they
want answers first.
It was the hope of the group that public pressure was not dictat-
ing programs and answers. Science must be cold-blooded and give
answers based on fact, not emotion. However, science does dictate
its needs and we do respond to this.
Overcaution so far as our environment is concerned should be
the goal for pest control specialists, and we should not use pesticides
unless their use can be completely justified. On this basis, DDT and
other insecticides should not be banned from use but should be
usable at least on a permit basis. With proper discretion in use, it is
possible that no permit, ban, or other restrictive measures would be
necessary.
-------
PART FOUR.
ANIMAL WASTES AS WATER POLLUTANTS
-------
CHAPTER SIXTEEN.
LIVESTOCK OPERATIONS
AND FIELD-SPREAD MANURE
AS SOURCES OF POLLUTANTS
J. R. MINER and T. L. WILLRICH
ISCHARGE of livestock and poultry manure into the environ-
ment is a practice as old as the animal. Historically, animal manure
was randomly deposited on the land surface where the nutrients
were utilized by growing vegetation and the organic matter was in-
corporated into the soil humus. Current livestock manure produc-
tion, in excess of 1.5 billion tons per year (Wadleigh, 1968), results
from a combination of the historical range or pasture production
and some degree of confinement in which traditional on-site soil
incorporation may not be applicable as a manure disposal system.
As much as 50% of the current manure production is from confine-
ment production (Law and Bernard, 1969).
POLLUTION CHARACTERISTICS OF ANIMAL WASTES
The major water pollutants arising from animal manures are
oxygen-demanding matter (principally organic matter), plant nu-
trients, and infectious agents. Color and odor are potential polluting
constituents of secondary importance. Organic matter from livestock
wastes, like that from other sources, serves as a substrate for aerobic
bacteria when it enters a receiving stream. Associated with bacterial
metabolism is the utilization of dissolved oxygen. When the rate of
oxygen utilization exceeds the reaeration rate of the stream, oxygen
depletion occurs. Whenever sufficient organic matter enters, oxygen
concentrations will be reduced below the level necessary for fish sur-
vival, and in more severe cases, complete oxygen depletion will occur
and cause the development of anaerobic conditions.
J. R. MINER is Assistant Professor, Department of Agricultural En-
gineering, Iowa State University. T. L. WILLRICH is Professor, De-
partment of Agricultural Engineering and Extension Agricultural
Engineer, Iowa State University.
Journal Paper No. J-6378 of the Iowa Agriculture and Home Econo-
mics Experiment Station, Ames. Project No. 1730. Prepared for pre-
sentation to A Conference Concerning the Role of Agriculture in
Clean Water, Ames, Iowa, November 18-20, 1969.
231
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232 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
TABLE 16.1. Pollutional characteristics of untreated animal wastes, sum-
mary of values.
Animal
Beef cow . . .
Dairy cow . .
Swine
Poultry ....
Animal
Weight
1,000
1,000
100
5
Solids
(Ib/day)
10.0
10.0
0.9
0.06
BOD
(Ib/day)
1.0
1.2
0.25
0.015
Nitrogen
(Ib/day)
0.3
0.4
0 06
0.003
Phosphorus
(Ib/day P2O5)
0.1
0.1
0.02
0.003
Organic matter in wastewater has historically been measured as
biochemical oxygen demand (BOD), This measurement evaluates the
concentration of oxidizable organic material that can be utilized by
aerobic bacteria in terms of how much oxygen they will require to
metabolize this material during a specified time, generally 5 days,
and at a specific temperature, generally 20° C. Having determined
the BOD and knowing the quantity of waste produced, it is possible to
determine a daily BOD production for various animal species. The
BOD of animal wastes has been evaluated by numerous researchers
(Jeffrey et al., 1964; Taiganides et al., 1964; Dornbush and Ander-
son, 1965; Hart and Turner, 1965; Witzel et al., 1966; Dale and Day,
1967; Jone^t al., 1968). From these data, representative BOD
quantities from various animals can be determined. These values are
summarized in Table 16.1.
Chemical oxygen demand (COD) is another measure of organic
and other oxygen-demanding water based on chemical rather than
biological oxidation. The COD exceeds the BOD of a waste due to the
inability of aerobic bacteria to completely oxidize the more resistant
constituents under the conditions of the BOD test. Table 16.2 com-
pares the BOD and and COD of various wastes by using untreated
municipal sewage as a reference.
In addition to oxygen depletion and resulting changes in aquatic
life, decomposing organic matter contributes to color, taste, and odor
problems in public water systems utilizing surface sources. Such
problems are often difficult to solve, yet are of great significance. Re-
duced inorganic substances, such as ammoniacal nitrogen, exert an
oxygen demand in addition to organic matter. Ammoniacal nitrogen
exert an oxygen demand in addition to organic matter. Ammoniacal
nitrogen concentrations ranging from 1 to 139 mg/1 were foimd in
feedlot runoff (Miner et al., 1966) and from 197 to 332 mg/1 in swine
manure lagoon effluent (Koelliker, 1969).
fAELg 16.2. BOD and COD concentrations in various wastes.
trpated
Source
domestic, sewaee
BOD
(mg/l)
100-300
COD
(rag /I)
400-600
Dairy cattle manure (Dale and Day, 1967) 25,600
Swine manure (Scheltinga, 1966) 27,000-33,000
Chicken droppings (Niles, 1967) 24,000
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CHAPTER 16 / LIVESTOCK OPERATIONS / 233
Nitrogen and phosphorus are the plant nutrients of primary
concern. These elements are present in sufficient quantities to in-
crease nutrient concentrations in surface water bodies and thus
stimulate the growth of aquatic plants. In addition, nitrate toxicity
due to increased nitrogen concentration in groundwater is important
in many rural areas.
Livestock wastes are sources of infectious agents that may infect
other animals and, in some instances, man. Among the potential
water-borne diseases transmissible from animals are anthrax, brucel-
losis, coccidiosis, encephalitis, erysipelas, foot rot, histoplasmosis, hog
cholera, infectious bronchitis, mastitis, Newcastle disease, ornithosis,
gastroenteritis, and salmonellosis (Wadleigh, 1968). Although water-
borne diseases are relatively rare in our country, increasing emphasis
on water-based recreation creates new opportunities for this mode of
infection. Leptospirosis has been spread from cattle to swimmers by
the water-borne route (Diesch and McCulloch, 1966). Samples of
cattle feedlot runoff, as small as one ml, showed the presence of
Salmonella organisms even though there were no symptoms of infec-
tion observed in the cattle (Miner et al., 1967). By using the fecal-
coliform—fecal-streptococcus ratio (Kenner et al., 1960) it is possible
to distinguish between livestock and human wastes. When stored in
a lagoon or applied to the soil, pollutional bacteria—coliform and en-
terococcal—die off rapidly (McCoy, 1967). Thus, little public health
hazard would appear due to lagooned livestock wastes. It was further
noted that for bovine wastes the predominant enterococci were Strep-
tococcus durans and S. faecium rather than S. faecalis found in the
human intestine. This suggests a different interpretation of entero-
coccal counts for animal than for human waste sources.
Since livestock wastes are not usually collected, transported, treat-
ed, and discharged into a receiving stream, as municipal sewage al-
most always is, a quantified prediction of water-quality deterioration
caused by animal wastes cannot be made as it can for municipal
sewage. Calculation of a population equivalent for the wastes from
various animals assumes that the total wastes from these animals are
discharged into streams and released at a uniform rate either with or
without treatment. Neither assumption is valid except in a most un-
usual situation.
However, the potential for livestock wastes to pollute water is
influenced by the ways in which it is collected, stored, and treated as
well as the final method of disposal. Seven major potential pollution
sources exist in connection with livestock wastes.
SURFACE WATER POLLUTION POTENTIAL
Runoff from Range and Pasture Operations
Where animals graze a vegetated land area (range or pasture),
little interest has been shown by water pollution control agencies.
Manure is uniformly distributed in a light application, liquids are ab-
sorbed by the soil, and the vegetative cover utilizes the added nu-
trients and inhibits erosion. Low-intensity rainfalls are usually ab-
-------
234 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
sorbed by the soil and high-intensity rainfalls in excess of soil infiltra-
tion rates provide sufficient dilution water to minimize the concentra-
tion of potential pollutants in the runoff.
In range and pasture systems, one can visualize extensive waste
treatment taking place as any runoff-carried pollutants pass over the
soil surface. Vegetative cover provides effective screening as well as
settling areas for particulate matter. Mixing and aeration stimulate
biological treatment of soluble organic matter. Thus, with respect to
water pollution potential, range or pasture livestock production is of
less concern than confinement production. However, when one con-
siders the use of a farm pond as a domestic water source, utilization
of the watershed as a pasture is discouraged because of the high-
quality water requirements and the relatively long die-off periods ex-
hibited by pathogenic organisms in such a system (Andre et al.,
1967).
Runoff from Cropland following Manure Application
When manure is spread on frozen or snow-covered fields, or
when heavy rainfall occurs immediately following manure applica-
tion, considerable runoff and a resulting organic matter and nutrient
loss is possible. Data from Wisconsin indicate that spring applica-
tion of manure caused no increase in loss of nitrogen in runoff.
Manure application on snow-covered ground that was followed by a
rain increased nitrogen losses from a normal 3 to 4 pounds per acre
annually to over 23 pounds (Hensler et al., 1969). Additional runoff
losses are possible where manure is stockpiled prior to spreading in
such a way that runoff has direct access to a surface stream.
Runoff from Feedlots and Similar Unroofed Enclosures
Animals produced in feedlots, pens, and other uncovered en-
closures in such a concentration as to remove the vegetative cover
present pollution hazards unlike the pasture systems. During and
immediately after rain and spring thaws, water flows over manure-
covered feeding areas and carries both particulate and soluble manure
components with it. This pollution source has received considerable
public interest due to the occurrence of dramatic fish kills and other
gross pollution incidents. The action of animal hooves on a feeding
surface creates an area void of vegetation and one through which in-
filtration rates are greatly reduced. However, considerable surface
storage capacity is available on feeding areas in the hoof depressions.
CATTLE FEEDLOT RUNOFF QUALITY
Data exist on the quality of runoff from cattle feedlots (Smith
and Miner, 1964; Miner et al., 1966; Loehr, 1968). They indicate cat-
tle feedlot runoff to be of highly variable quality, depending upon
-------
CHAPTER 16 / LIVESTOCK OPERATIONS / 235
such factors as rainfall intensity, temperature and feedlot surface
moisture content, and manure accumulation. Organic content as
COD in cattle feedlot runoff ranged from 3 to 11 times the COD in
untreated domestic sewage (Miner et al., 1966). Although runoff
from feeding areas confining animals other than cattle may be ex-
pected to be high in organic matter, no data are currently available
concerning these sources. In addition to the high-strength character-
istics of feedlot runoff, the slug effect upon a receiving stream is par-
ticularly damaging. When feedlot runoff is uncontrolled, particularly
from a lot located adjacent to receiving streams, the large volume of
relatively high-strength wastewater enters the stream quickly and
consequently allows little time for dilution by runoff from clean areas.
Thus, one technique proposed for the reduction of feedlot runoff dam-
age is the construction of flow control structures that spread the dis-
charge of runoff over a longer time period. Of particular concern to
pollution agencies have been large feedlots (capacity over 1,000 head),
lots located near or adjacent to streams, or lakes and lots whose run-
off enters groundwater supplies through abandoned wells, springs,
sinkholes, or other openings.
In assessing the significance of cattle feedlot runoff compared
with other waste sources within a drainage basin, one must look at
both the quantity and quality of runoff. Assuming an earthen lot
with a 2% slope, about 11 inches of annual runoff might be expected
from 30 inches of annual rainfall, with runoff occurring during 30
days of the year. At an average of 1,000 mg/1 of BOD, the runoff
from a feedlot on each of these 30 days would be equivalent to the un-
treated sewage from a community of 500 people per acre of feedlot
surface. Although such an average is of little help in actual situa-
tions, it indicates that runoff from cattle feedlots is a significant
source of organic wastes, but it is not of the same magnitude as one
gets if he bases his predictions on standard population equivalents for
various livestock.
CONTROL OF CATTLE FEEDLOT RUNOFF
In response to fish kills attributable to feedlot drainage (Loehr,
1968) and for other reasons, such as stream enrichment, various pol-
lution control measures have been devised. The first step in most pro-
grams is to divert any water falling outside the feedlot so that it will
not flow across the feedlot and thereby minimize the quantity of pol-
luted runoff. The second step is generally the construction of a run-
off collection and impoundment system that will prevent the im-
mediate and uncontrolled entry of runoff into a stream. Facilities to
settle manure solids are frequently incorporated into either the run-
off collection system by the design of channels for low flow velocities
or by the construction of separate settling basins. Settling facilities
are designed for flow velocities of 1 foot per second or less and for
dewatering so collected solids will dry more rapidly and thus more
easily. Where solids are to be removed from a settling basin with a
dragline, a maximum basin width of 50 feet is desirable.
-------
236 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
Runoff impoundment basins generally provide sufficient capacity
to hold 3 to 6 inches of runoff from the contributing area. The final
design capacity is a function of the climatological features of the
area and the proposed method for disposing of collected runoff. In
some parts of the country where seasonal and annual evaporation
losses sufficiently exceed rainfall quantities, it is possible to design
runoff impoundment basins so that most or all collected water will
be lost by evaporation and seepage. This approach is not applicable
in humid regions, however.
Where evaporation and seepage losses are not sufficient for run-
off disposal, collected wastewater may be spread on land or treated
prior to release into a stream or surface water body. Problems as-
sociated with wastewater treatment are (1) the necessity of frequent
operator attention, (2) the difficulty in producing a high-quality ef-
fluent, and (3) the costs involved in such treatment.
Discharge from Waste Storage or Treatment Units
Roofed livestock confinement units offer advantages to the pro-
ducer in ease of mechanizing feed and water distribution and manure
collection as well as offering the possibility of environmental control.
Such units range from unheated structures with natural ventilation
to totally enclosed buildings with mechanical ventilation as well as
heating and cooling equipment.
To perform satisfactorily, an enclosed livestock building must in-
corporate a compatible manure management system. A manure man-
agement system may logically incorporate (1) a means to separate the
manure from the animal and to collect it in some logical place, (2) a
method to transport it, (3) a storage device, (4) one or more treatment
units, and (5) a final disposal or utilization scheme. These functions
must be mutually compatible as well as being compatible with the
remainder of the production unit. They must not only control the
escape of potential water pollutants but also minimize the potential
for odor, insect, and rodent nuisances, and operate with a minimum
of labor, capital investment, and operating costs.
Totally roofed animal units eliminate the open-lot runoff prob-
lem but they offer the greatest potential for water pollution of all the
livestock production schemes. They also offer the greatest potential
for essentially pollution-free operation. System design and manage-
ment determine the degree of pollution that will develop, if any. As
an example, a 1,000-head beef unit would be equivalent to a com-
munity of 6,000 people, based on BOD, if the raw wastes were
dumped into a stream every day, or a community of up to 600,000 if
the accumulated wastes were dumped every 100 days. However, with
proper waste collection, transport, and application to cropland, the
manure from this operation need not contribute to water pollution.
Liquid manure systems are most common in roofed confinement
units. Liquid manure may be applied to the soil with or without treat-
ment as just discussed. Treatment for release into high-qualitv sur-
face waters has not been recommended due to the inability of cur-
-------
CHAPTER 16 / LIVESTOCK OPERATIONS / 237
rently available systems to produce an acceptable effluent at a rea-
sonable cost.
GROUNDWATER POLLUTION POTENTIAL
Percolate from Feedlots and Similar Unroofed Enclosures
Whenever water passes through a layer of manure and perco-
lates into the underlying soil, it will carry certain components of the
manure with it. Because of soil puddling and compaction by animal
hooves, however, the infiltration rate in an animal feeding area will
usually be low. Thus, only a very small quantity of water would be
expected to enter the groundwater supply as long as the lot is in con-
tinuous use to confine animals. Where soil and groundwater samples
have been collected near old feedlcts, elevated nitrate-nitrogen con-
centrations have been detected (Smith, 1967). Data collected from
beneath feedlots and irrigated fields of the South Platte Valley in
Colorado also indicated elevated nitrogen concentrations in ground-
water near feedlots (Stewart et al., 1968). They also noted high or-
ganic carbon concentrations in groundwater samples as much as 35
feet beneath feedlots. High organic carbon concentrations caused
much of the nitrogen to be present as ammonium nitrogen. Thus, lo-
calized pollution of the water-table aquifer with nitrogen near and
under animal feeding areas does take place. However, due to the
limited acreage being used for feedlots, widespread groundwater
pollution due to infiltration from animal feeding areas is not likely.
Percolate from Disposal Areas
Most animal manure is spread on cropland. This includes not
only manure and other wastes scrapped from open feedlots but also
that hauled, both solid and liquid wastes, from confinement buildings
and barns as well. This manure is field spread not only because of its
fertilizer value but also as a convenient and least-cost disposal tech-
nique in most situations. Current manure-spreading techniques in-
clude not only conventional solid manure spreaders but also liquid-
hauling tanks and irrigation equipment. Two potential modes of pol-
lution exist for manure applied to cropland: (1) runoff due to rainfall
or snowmelt carrying it to surface streams or impoundments and (2)
percolation into the groundwater.
Where collected feedlot runoff or liquid manure is spread on crop-
land, forest land, or pasture, the greater portion of pollutants will be
removed from the wastewater before it becomes a portion of the
groundwater recharge. Soil has the ability to remove all suspended
solids and much of the dissolved material. BOD and COD removal
should present no problem as long as the infiltration capacity of the
soil is maintained. Soil also has the ability to absorb large quantities
of phosphorus. Nitrogen, however, can escape to the groundwater
and thus sufficiently increase the nitrate concentration in a localized
-------
238 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
area so that the groundwater would be of inferior quality for some
uses.
Recent work with application of anaerobic animal wastes to
grassland indicates that with proper management extensive biologi-
cal denitrification is possible (Koelliker and Miner, 1969). In one
trial, using anaerobic lagoon effluent, 2,300 pounds of nitrogen per
acre were applied in 30 inches of lagoon effluent. Losses to ground-
water (250 Ib/A) and in runoff (170 Ib/A) were 420 pounds per acre.
A net nitrogen loss within the soil profile of 400 pounds per acre was
measured. Thus, a loss of 2,020 pounds of nitrogen per acre due to
denitrification took place during the 3-month trial period.
Percolate from Field-spread Manure
Groundwater pollution due to field-spread manure has generally
been of b'ttle significance, due to the associated organic matter which
tends to release nitrogen over an extended time period and due to
the conventional rates of manure application. This mechanism al-
lows the nutrients greater opportunity to be used by crops or be in-
corporated into the soil. The soil is also effective in removing po-
tentially infectious bacteria; 14 inches of silt loam soil removed the
initial concentrations of 1 X 105/rnl of Escherichia coli and of
1 X 10G to 1 X 107/ml of enterococci (McCoy, 1969).
SUMMARY
1. Potential water pollutants from animal manures are oxygen-de-
manding matter, plant nutrients, infectious agents, and color-
and odor-contributing substances.
2. Total solids in animal manures are about 300 times more con-
centrated than in municipal sewage. The BOD of undiluted
animal manures is about 100 times greater than the BOD of
municipal sewage.
3. Ammoniacal nitrogen concentrations in diluted and decomposed
animal wastes, such as lot runoff and lagoon effluent, are suffi-
cient to exert a major oxygen demand or produce a toxic level
to fish in a receiving stream.
4. The incidence cf water-borne diseases transmitted from animal
to man is low even though a dozen or more diseases can be trans-
mitted by this route. Fecal enterococcal counts must be inter-
preted differently for animal-manure-polluted water than for hu-
man-waste-polluted water since nonpathogenic enterococci ap-
parently predominate in some animal wastes. Most infectious
agents die off rapidly when animal wastes are treated or applied
to the soil.
5. Data concerning pollutants removed by runoff from livestock
range and pasture operations are sparse. Logic indicates that
this potential source is relatively insignificant when compared
to other sources.
-------
CHAPTER 16 / LIVESTOCK OPERATIONS / 239
6. Runoff from manured cropland will transport greater quantities
of pollutants if the manure has been spread on frozen or snow-
covered fields.
7. Highly concentrated open feeding areas offer the potential for
runoff-caused pollution problems, due to the low infiltration rates
and high manure density. Runoff control is one key to pollution
prevention. Manure cleaned from lots and collected runoff re-
quires some means of disposal. Land application is the current
disposal means of preference.
8. Roofed confinement livestock buildings make possible a high
degree of control over manure disposal. A proper means for con-
trol of this material requires systems for manure collection,
transport, storage, treatment, and/or disposal or utilization. Hy-
draulic manure transport systems offer improvements in labor
requirements but unless some means of water reuse is planned,
excessive waste disposal expense is encountered. Improper ma-
nure disposal from such a unit causes the greatest pollution
threat of the systems mentioned.
9. The application of livestock manure to the soil is both a logical
and historically verified practice. Technological, social, and eco-
nomic factors have in recent years made this practice less ac-
ceptable. Applied in proper quantities with alert management,
and with improved methods of application, manure disposal by
return to the soil should be encouraged. This disposal may ne-
cessitate treatment and conditioning prior to disposal to mini-
mize odors or water pollution.
REFERENCES
Andre, D. A., Weiser, H. H., and Maloney, G. W. 1967. Survival of
bacterial pathogens in farm pond water. /. Am. Water Works
Assoc. 59(4): 503.
Dale, A. C., and Day, D. L. 1967. Some aerobic decomposition prop-
erties of dairy-cattle manure. Trans. Am. Soc. Agr. Engrs.
10 (4): 546-48.
Diesch, S. L., and McCulloch, W. F. 1966. Isolation of pathogenic
leptospires from waters used for recreation. Public Health Kept.
81 (4): 299-304.
Dornbush J. N., and Anderson, J. R. 1965. Lagooning of livestock
wastes in South Dakota. Proc. 1964 Ind. Waste Conf. Lafayette,
Ind.: Purdue Univ. Eng. Ext. Ser. 117, pp. 317-25.
Hart, S. A., and Turner, M. E. 1965. Lagoons for livestock manure.
J. Water Pollution Control Federation 37(11): 1578-96.
Hensler R F. Olsen, R. J., Witzel, S. A., Attol, O. J., Paulson, W. H.,
and Johannes, R. F. 1969. Effect of method of manure han-
dlino- on crop yields, nutrient recovery and runoff losses. Pre-
sented at meeting of Am. Soc. Agr. Engrs., 22-25 June 1969,
W. Lafayette, Ind.
Jeffrey E A. Blackman, W. C., and Ricketts, R. L 1964 Aerobic
and anaerobic digestion characteristics of livestock wastes.
Univ. of Mo. Eng. Ser. Bull. 57.
-------
240 / PART 4 I ANIMAL WASTES AS WATER POLLUTANTS
Jones, D. D., Jones, B. A., and Day, D. L. 1968, Aerobic digestion of
cattle wastes. III. Res. 10 (2): 16-18.
Kenner, B. A., Clark, H. F., and Kablet, P. W. 1960. Fecal strepto-
cocci: quantification of streptococci in feces. Am. J. Public
Health 50 (10): 1553-59.
Koelliker, J. K. 1969. Soil percolation as a renovation means for
livestock lagoon effluent. Unpublished Master's thesis, Iowa
State Univ., Ames.
Koelliker, J. K., and Miner, J. R. 1969. Use of soil to treat anaerobic
lagoon effluent renovation as a function of depth and applica-
tion rate. Paper 69-460 presented at meeting of Am. Soc. Agr.
Engrs., 22-25 June 1969, W. Lafayette, Ind.
Law, J. B., and Bernard, H. 1969. The impact of agricultural pollut-
ants on subsequent users. Paper 69-235 presented at meeting
of Am. Soc. Agr. Engrs., 22-25 June 1969, W. Lafayette, Ind.
Loehr, R. C. 1968. Pollution implications of animal ivastes—a for-
ward oriented re-view. U.S. Dept. of Interior, Fed. Water Pollu-
tion Control Admin., Robert S. Kerr Water Res. Center, Ada,
Okla.
McCoy, E. 1967. Lagooning of liquid manure (bovine): bacterio-
logical aspects. Trans. Am. Soc. Agr. Engrs. 10 (6): 748-87.
. 1969. Removal of pollution bacteria from animal wastes by
soil percolation. Paper 69-430 presented at meeting of Am. Soc.
Agr. Engrs., 22-25 June 1969, W. Lafayette, Ind.
Miner, J. R., Lipper, R. I., Fina, L. R., and Funk, J. W. 1966. Cattle
feedlot runoff: its nature and variation. /. Water Pollution
Control Federation 48 (10): 1582-91.
Miner, J. R., Fina, L. R., and Piatt, C. 1967. Salmonella infantis in
cattle feedlot runoff. /. Appl. Microbiol. 15 (3): 627-28.
Niles, C. F. 1967. Egglaying house wastes. Proc. 22nd Ind. Waste
Conf. Lafayette, Ind.: Purdue Univ. Eng. Ext. Serv. 129, p. 334.
Scheltinga, H. M. J. 1966. Aerobic purification of farm waste. /.
Proc. Inst. Sewage Purification, pp. 585—88.
Smith, G. E. 1967. Fertilizer nutrients as contaminants in water
supplies. In Agriculture and the quality of our environment,
ed. N. C. Brady, pp. 173-86. Norwood, Mass.: Plimpton Press.
Smith, S. M., and Miner, J. R. 1964. Stream pollution from feedlot
runoff. Trans. 14th Ann. Conf. Sanit. Eng., pp. 18-25. Univ.
of Kans., Lawrence.
Stewart, B. A., Viets, F. G., and Hutchinson, G. L. 1968. Agriculture's
effect on nitrate pollution. /. Soil Water Conserv. 23 (13): 13-15.
Taiganides, E. P., Hazen, T. E., Baumann, E. R., and Johnson, H. P.
1964. Properties and pumping characteristics of hog waste.
Trans. Am. Soc. Agr. Engrs. 7 (2): 123-29.
Wadleiffh. C. H. 1968. Wastes in relation to agriculture and forestry.
USD A Misc. Publ. 1065.
Witzel, S. A., McCoy, E., Polkowski, L. B., Attoe, O. J., and Nichols,
M. S. 1966. Phvsical, chemical and bacteriological properties
of bovine animals. In Management of farm animal ivastes.
St. Joseph, Mich.: Am. Soc. Agr. Engrs. SP-Oe66, pp. 10-14.
-------
CHAPTER SEVENTEEN.
MANURE DECOMPOSITION AND
FATE OF BREAKDOWN PRODUCTS
IN SOIL
T. M. McCALLA, L. R. FREDERICK, AND G. L. PALMER
UGE quantities of animal waste are accumulating in small
areas because of the increasing confinement of animals in large
numbers for meat, milk, and egg production (Wadleigh, 1968). The
production of enormous amounts of urine and fecal material has
caused unparalleled disposal problems and a threat to water quality
(Commoner, 1968). The best way to dispose of animal waste is to
put it on the land for decomposition and mineralization. But what is
the highest concentration of animal waste can be applied to the
land without upsetting favorable microbial decomposition patterns,
producing a toxic effect on the crop, or polluting the runoff and
groundwater?
There are some waste treatments that can be applied to animal
manure to remove its high oxygen demand and inorganic nutrients,
but these treatments are not yet economically feasible.
Much can be done in the management of the animal waste on
site (for example, on beef cattle feedlots) to create a favorable en-
vironment for decomposition so that a considerable amount of the
manure can be decomposed to COo and N2, which will dissipate into
the atmosphere (Dale and Day, "1967; McCalla and Viets, 1970).
Phosphates are readily adsorbed by the soil and thus may be removed
effectively from solution. Therefore, correct management can re-
duce eutrophication1 in streams and lakes.
T. M. McCALLA is Microbiologist, USDA, Lincoln, Nebraska. L. R.
FREDERICK is Professor, Department of Agronomy, Iowa State Uni-
versity. G. L. PALMER is Instructor, Department of Agronomy, Iowa
State University.
Contribution from the Northern Plains Branch, Soil and Water Con-
servation Research Division, ARS, USDA, in cooperation with the
Nebraska Agricultural Experiment Station, and from the Agronomy
Department, Iowa State University, Ames. Published as Paper No.
2742, Journal Series, Nebraska Agricultural Experiment Station; and
Paper No. J6431, Iowa Agricultural Experiment Station, Project 1378.
1. Eutrophication is an excessive enrichment of water with nutri-
ents, such as nitrates and phosphates, which will promote a luxuri-
ant growth of algae (algal bloom).
241
-------
242 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
TABLE 17.1. Chemical composition of various fresh manures, litter free.
Chemical Constituents
Ether-soluble substances
Cold water-soluble organic matter .
Hot water-soluble organic matter . ,
Heniicelluloses
Cellulose
Lignin
Total nitrogen
Ash
Sheep Horse
Manure* Manure
(percent of dry
2.83 1.89
, 19.19 3.19
5.73 2.39
18 46 23.52
18.72 27.46
20.68 14.23
4.08 1.09
. 17.21 9.11
Cow
t Manure*
material)
2.77
5.02
5.32
18.57
25.43
20.21
2.38
12.95
Source: Waksman (1938).
* Solid and liquid excreta.
t Solid excreta only.
MANURE COMPOSITION
Fresh manure contains from 30 to 85% water. The rest of the
constituents in manure are inorganic and organic solids, liquids, and
gases. The composition of manures is shown in Tables 17.1, 17.2,
17.3, and 17.4.
Manure contains all the inorganic nutrients needed by plants.
These nutrients are worth slightly more than $1 per ton (Table 17.4).
When putting large quantities of manure on land, materials such as
ammonia may accumulate in concentrations toxic for the growth of
plants (McCalla and Haskins, 1964; Megie et al., 1967). Using average
figures for production of manure per animal unit and agricultural
statistics for the number of animals present in the various states,
an estimate of the N, P, and K in manure produced by livestock in
the north-central region of the United States was made. For the
western north-central states, the manure contained per year 2,100,000
tons N, 300,000 tons P, and 1,300,000 tons K. Similar figures were
obtained for the eastern north-central states. These figures are ap-
proximately comparable to the nutrients applied as fertilizer in
1968, except that about 50% more phosphorus was applied as fertil-
izer.
Roughly, 90% of the dry matter in manure is organic waste
material from animal digestion of feeds. Animal rations consist
largely of carbohydrates (sugars, starches, celluloses, and hemicellu-
loses), some proteins, fats, small amounts of lignin, and numerous
inorganic nutrients, such as nitrogen, phosphorus, potassium, and a
number of micronutrients (Hemingway, 1961; Gilbertson et al.,
1970). In a high-concentrate ration, about 70 to 80% of the organic
nutrients are utilized by the animal. The substances used by the
animal are mostly carbohydrates, some proteins, small amounts of
minerals, and other substances. The animal waste is more concen-
trated than the feed in lignin and minerals upon deposition in feed-
lot or confinement structure and is less concentrated in carbohy-
drates. But the manure retains about 60 to 75% digestible materials.
Some fats are present, and also humiclike substances resistant to
-------
TABLE 17.2. Characteristics of animal manures.
Animal
Dairy cattle
Fattening cattle • •
HOGS ,
Horses ,
Sheep
Moisture
%
, . . 79
, . . . 80
. . . . 75
. . . . 60
. . 65
N
11 2
14.0
10.0
13.8
28.0
P
2 0
4.0
2.8
2.0
4.2
K
10 0
9.0
7.6
12.0
20.0
S
1 0
1.7
2.7
1.4
1.8
Characteristics
Ca Fe
(Ib/ton manure)
56 0 08
2.4 0.08
11.4 0.56
15.7 0.27
11.7 0.32
Mg
2 2
2.0
1.6
2.8
3.7
Volatile
Solids
322
395
399
386
567
Fat
7
7
9
6
14
Source: Loehr (1968).
-------
TABLE 17.3. Trace element content of manures (as ppm, dry-matter basis).
Element
Minimum
Maximum
Average
Boron
Manganese
Cobalt
Copper
Zinc
Molybdenum
Molybdenum*
4.5
75.0
0.25
7.6
43.0
0.84
0.84
52.0
549.0
4.70
40.8
247.0
15.83
4.18
20.2
201.1
1.04
15.6
96.2
2.37
2.06
Source: Atkinson et al. (1954).
Note: Data from 44 samples of farmyard manure, representing fresh cow,
horse, swine, sheep, poultry, and mixed manures, and composted cow and
mixed manures.
* With one exceptionally high value omitted.
TABLE 17.4. Chemical analysis of slurry manure (a mixture of feces and
urine) from confined beef cattle feeding in Nebraska.
Constituent
N
Moisture
Volatile solids
Total solids
Ash
NH,
COD
PH
Conductivity
Wet Weight
Basis
O.299b
0.18%
0.31%
85.0 %
11.6 %
15.33%
3.73%
0.05%
0 %
121,000 mg. (Vliter
7.3
4.5 mmhos/cm2
Each Ton
Contains
5.8 Ib.
3.6 Ib.
6.2 Ib.
20T/A
Supplies
116 Ib.
72 Ib.
124 Ib.
Note: Acknowledgment is made of the assistance of J. R. Ellis, USDA-ARS-
SWC, in making these determinations.
TABLE 17.5. Particle size analysis of fresh ma-
nure (oven-dry weight basis).
Particle Size
Percent of Total
4.00 mm or greater
4.00 mm but >2,000ju
but
but
but
2.45
25.09
36.69
4.75
1.01
30.02
Source: Unpublished data, T. M. McCalla and
J. S. Boyce (1969).
-------
CHAPTER 17 / MANURE DECOMPOSITION IN SOIL / 245
decomposition (Jansson, 1960a, 1960b; Alexander, 1961). Antibiotics
may also occur in the animal waste (Morrison et al., 1969).
The mechanical size of the particles in manure is shown in
Table 17.5. The solids consist of undigested fragments of grain,
bran, fibrous materials, and about 30% colloidal materials.
The microbial population of animal waste is composed mainly
of bacteria, fungi, actinomycetes, and protozoa. Cells of microbes
and cells from the lining of the intestinal tract of the animal in
feces amount to about 40% of the feces (Crampton and Harris,
1969). Among the bacteria, the enterococci and coliforms are very
numerous, with coliform counts as high as 18 billion excreted per
animal per day (Table 17.6).
Fresh manure, a manure-soil-urine mixture from next to the
concrete feeding apron, and dry manure from the middle of the feed-
lot were collected in eastern Nebraska. A manure suspension, 5%
by weight (oven-dry basis), was made by shaking manure and dis-
tilled water for 1 hour. After standing for 0, 1, and 24 hours, both
solubility of substances and suspension of the manure, and the num-
ber of microorganisms in the supernatant, were determined (Table
17.7). Highest solubility and suspension of combustible material
were found in fresh manure, and greatest solubility and suspension
of noncombustible material were found in samples collected next
to the feedlot bunkers. Appreciable numbers of microbial pollution
indicators were present, and they remained in suspension even after
24 hours of settling. The amount of phosphorus and nitrate in sus-
pension and solution remained high after settling. Concentration of
total P of material in suspension and solution was approximately
68 to 113 ppm and for NO:fN was 8.5 to 23 ppm. The pH decreased
sharply when the fresh manure suspension was allowed to stand for
24 hours. Thirty percent of the manure was in particle sizes less
than 2/ji. Salter and Schollenberger (1939) found up to 50% of
manure was humus. Shigella and Salmonella were not found in the
manure samples. The orders of magnitude of the microbial counts
in the manure suspension were: total count, 10s; anaerobes, 105 to
10C; Escherichia coli, 105; enterococci, 104 to 10°; and total fungi,
103 to 105 per ml of manure suspension.
MANURE DECOMPOSITION IN FEEDLOTS, CONFINEMENT
AREAS, AND IN THE SOIL
Decomposition in Storage
Animal waste may remain where deposited in feedlots and con-
finement buildings for considerable time before disposal, and much
decomposition may occur. For example, manure from beef cattle
with a high-roughage diet was incubated in a growth chamber simu-
lating spring and summer climatic conditions at Lincoln, Nebraska.
Urine was added twice weekly to the incubated manure samples to
equal two stocking rates: 50 and 250 ft2 per animal. After 3 weeks
of decomposition, 90% of the nitrogen added initially in the manure
-------
TABLE 17.6. Estimated daily per capita discharge of coliforms in animal feces.
8
Item
Moisture content (%)
Average weight of 24-hr fecal
discharge (wet weight in
grams) ,
Coliforms per gram (millions) . . . . ,
Total coliforms discharged
per day (millions)
Human
. . 77.0
. . . . 150.0
, . . . 13.0
. . . . 1,950.0
Cow
83.3
23,600.0
0.23
5,428.0
Hog
66.7
2,700.0
3.3
8,910.0
Sheep
74.4
1,130.0
16.0
18,080.0
Ducks
61.0
336.0
33.0
11,088.0
Turkeys
62.0
448.0
0.29
130.0
Chickens
71.6
182.0
1.3
237.0
Source: Geldreich et al. (1962).
-------
TABLE 17.7. Numbers of microorganisms and chemical tests on 5% suspension of manure in distilled water. Numbers pere
ml or mg/ml or ppm of manure suspension.
to
Kind of
Manure
Sample H,O
%
Do 95
Di
D2l
Mo 95
Mt
MM
Fo 95
Ft
FB,
pll
7.8
7.2
7.6
8.2
8.6
7.8
6.8
5.6
4.94
Bacteria
per ml
CX10")
490.0
303.0
120.0
245.0
257.0
73.0
303.0
187.0
8.5
Fungi
per ml
(xio1)
0.3
0.3
5.7
3.0
13.0
10.0
63.0
10.0
24.0
Anaerobes
per ml
E. coli
per ml
Entero-
cocci
per ml
Nonvol.
res. wt.
Vol.*
res. wt.
In suspension
(XlOr') (xlO7') (xlO*) (mg/ml)
1.7
0.3
0.1
21.3
27.3
0.99
t
3.0
t
7.0
13.0
0.29
7.0
3.0
2.9
t
13.0
0.4
7.0
17.0
8.8
293.0
183.0
487.0
53.0
71.0
80.0
4
6
6
19
12
7
6
4
4
18
25
19
24
18
13
6
4
3
Total
Phos-
phorus
NCVN
(ppm for solution)
60
113
88
60
88
60
100
100
88
13.8
13.7
14.5
23.7
23.9
23.5
8.5
10.6
10.7
Source: Unpublished data, T. M. McCalla and J. R. Ellis, (1968).
* = combustible at 550° C.
t = numbers below or above dilutions made.
D — dry manure
M = mixture of soil, manure, and urine near feed bunker
F = fresh manure
0 = 0 times of standing after shaking
1 = 1 hour of standing after shaking
24 = 24 hours of standing after shaking
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248 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
or subsequently in the urine was lost into the atmosphere with the
stocking rate of 50 ft2 per animal. In the decomposing manure,
NH3 concentrations were high, pH ranged from about 8 to 9, nitrates
accumulated only to a slight extent, COD values remained high, and
salt concentration increased. About 50% of volatile solids were lost
in 4 months (McCalla et al., 1969b). In Connecticut, 3 bushels of
fresh manure from dropping pits lost 55% of the organic matter and
77% of the N when stored for 20 weeks in a laying house (Perkins
et al., 1964). With the loss of carbon and nitrogen, mineral content
increased, readily available organic materials decreased, and resistant
materials such as lignin accumulated (Burnett and Dondero, 1969).
Manure oxygen demand is characterized as BOD2 and COD3 values
(McCalla et al., 1969b).
The BOD:COD ratio generally is about 8.5:10 for beef cattle
manure (Lipper, 1969). Morrison et al. (1969) showed that excreted
chlortetracycline in beef cattle feedlot waste, arising from antibiotic
supplementation of the ration, had a half-life of 1 week at 37° C and
greater than 20 days at 28° C and 4° C. By altering decomposition
patterns, antibiotics or other chemicals may affect release of nui-
sance odors.
The microorganisms found in manure during decomposition are
bacteria, fungi, actinomycetes, and protozoa (Witzel et al., 1966;
McCoy, 1967, 1969). Many of the E. coli, enterococci, and other
intestinal and disease microorganisms are short-lived in the soil
(King, 1957; Burroughs, 1967; Klein and Casida, 1967). In a manure
decomposition study at Nebraska, the E. coli and enterococci dis-
appeared rapidly, and none remained after the second and third
months. Fungi numbers were very low initially, but increased during
the incubation period. Bacilli decreased; total bacteria increased
(McCalla et al., 1969b).
Decomposition in Soil
The addition of large amounts of manure will stimulate the
growth of saprophytic bacteria, fungi, and actinomycetes in the soil.
Aerobic, mesophilic bacteria metabolizing cellulose are much more
numerous in manured fields. Protozoan and actinomycete numbers
and COo production are increased by manure additions (Alexander,
1961).
Manure from a high-concentrate ration contains about 10 to
15% lignin. Most of the other energy material decomposes rather
rapidly in the soil. Polysaccharides, including cellulose and starch,
and most protein materials decompose rapidly, although some of
the proteinaceous material, probably associated with lignin or kera-
tin, is fairly resistant to decomposition (Polheim, 1965). Consider-
2. Biological oxygen demand is the oxygen consumed by microbes in
the process of oxidizing the organic materials during a 5-day incuba-
tion period. This is basically an indication of the readily oxidizable
material present.
3. Chemical oxygen demand is a chemical evaluation of the total
oxidizable material using sulfuric acid and potassium dichromate,
the measure being the quantity of oxygen used in this process.
-------
CHAPTER 17 / MANURE DECOMPOSITION IN SOIL / 749
Unlobe led carbon, mean of all
treatments
Labeled carbon, mean of all
treatments
Period of incubation, years
FIG. 17.1. Losses of unlabeled (soil) and labeled (ryegrass) carbon
from soils incubated in the field with labeled ryegrass. (Jenkinson,
1965.)
able carbon and nitrogen are found in microbial cells formed during
decomposition. Of labeled C added as 0.6% ryegrass to Broadbalk
field soils, Jenkinson (1966) found that 30 to 33% remained in the
soil after 1 year, of which about one-third was in microbial cells.
After 4 years, 19% of the labeled C still remained, and only about
19% of that was in microbial cells. The carbon turnover rate
appeared to vary with stage of decomposition: the original residues
decomposed rapidly with a half-life estimated to be 14 to 30 days.
After the first year, the biomass has a half-life of 1 year, and the
residual C has a half-life of about 4 years, while the soil humus has
a half-life of about 25 years (Figure 17.1). About 50 to 60% of the
nitrogen in manure applied to soil will be mineralized the first year.
Factors Affecting Decomposition
Under aerobic conditions, carbonaceous materials are rapidly
oxidized to CO2; microbial cells are synthesized; and nitrates, sul-
fates, and inorganic phosphate tend to accumulate. Manure added
in large quantities to the soil has a tremendous O2 demand. Well-
-------
TABLE 17.8. Generalized presentation of breakdown products of manure decomposed under aerobic and anaerobic conditions.
Type of
Material
Breakdown
products
Aerobic
Carbon Nitrogen Phosphorus Sulfur
corn- com- com- com-
pounds pounds pounds pounds
CO, NCV HJPO<- SO,=
Microbial
cells
Anaerobic
Carbon
com-
pounds
CO,, CH,
Organic
acids
Alcohols
Cells
Nitrogen
com-
pounds
N2, NHa
Pyridines
Indoles
Skatoles
Amines
Phosphorus Sulfur
com- com-
pounds pounds
H,POr S=
Mercaptans
H2S
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CHAPTER 17 / MANURE DECOMPOSITION IN SOIL / 251
drained soil is aerobic, but the soil environment may become anaero-
bic, particularly if conditions are favorable for decomposition and
there is an excess of water.
Under anaerobic conditions, which will occur in a very wet soil
(as in over-irrigation), denitrification can occur. A considerable
amount of the nitrogen may be lost into the atmosphere, because
1 unit of N can be lost for each 3.1 units of carbohydrate metabolized
to CO,.
Many anaerobic decomposition products, such as organic acids
(acetic, butyric, propionic, isobutyric) and other compounds, may
be unfavorable for plant growth. The iron may be reduced to a fer-
rous condition. Foul-smelling compounds, such as indole, skatole,
mercaptans, hydrogen sulfide, and amines, are byproducts of protein
decomposition (Table 17.8).
Temperature is another important factor. When the soil is cold,
decomposition is slow. Rothwell (1955) found that breakdown rates
at 45°, 60°, 70°, and 80° F were about 30, 60, 70, and 80% , respec-
tively, of the rate at 95° F.
The maximum amount of manure that the soil will accommo-
date in decomposition has not been determined. Indeed, if the land
were covered with several inches of manure, considerable decompo-
sition would occur in the manure pack where thermophilic bacteria
may be active in the decomposition. Temperature in manure packs
will reach 160° F even in winter.
FATE OF BREAKDOWN PRODUCTS IN SOIL
Application of animal waste to the surface or incorporation in
the soil is followed by further decomposition. Manure should be
immediately plowed under to minimize N loss (Table 17.9). About
three-fourths or more of the organic materials W7ill be decomposed
in the first year. The mineralization of the animal waste will result
in nitrogen, phosphorus, potassium, and micronutrients becoming
available to plants, but there is no evidence that manure is superior
to inorganic fertilizer (Tables 17.10 and 17.11). Further evidence is
needed to evaluate any contribution due to organic matter present
TABLE! 17.9. Effect of plowing manure under at different times after appli-
cation on crop yield.
Relative Value in
Increasing Crop Yields
Oats
(15 experi-
ments)
Manure plowed under immediately 100
Manure plowed under 6 hours after spreading 79
Manure plowed under 24 hours after spreading 73
Manure plowed under 4 days after spreading . . 57
Potatoes
(1 experi-
ment)
100
86
70
44
Source: Salter and Schollenberger (1939).
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252 / PART 4 / ANIMAL WASTES AS WATER POUUTANTS
TABLE 17.10. Long-time yields with manure and fertilizer are comparable.
Place
Rothamstead,
England ....
Ohio
Missouri
Crop
Wheat
Corn
. Wheat
Years
>150
> 75
> 50
Manure
(bill a)
32
58
19
Fertilizer
(bn/a)
34
53
20
None
(bul a)
12 6
32 0
10.0
or microorganisms carried and growth-promoting or growth-inhibit-
ing effects possible. Embleton and Jones (1956) showed that yield
of oranges was the same when 2 pounds of nitrogen were applied
per tree as manure or as commercial fertilizer annually when the
soil was tilled, but was lower with manure applications when the
soil was not tilled. Manure was also an efficient source of phosphate
and potash for the trees.
Excessive mineralization of animal waste in the soil may result
in leaching of nitrate into the groundwater and runoff with N and
P. Huge quantities of animal waste applied to the land may result
in accumulation of some organic and inorganic constituents in con-
centrations that may become toxic to plants, particularly under an-
aerobic decomposition conditions (Megie et al., 1967). For example,
corn seeds planted into manure will not germinate (Figure 17.2).
Gaseous products, such as CO2, NH3, NOo, NoO, and N2, become
a part of the soil air and may return to the atmosphere. Small
amounts of organic acids and other odor-forming compounds are
gaseous. When released in the soil, some (e.g., NH3, NOo, H2S)
may be sorbed, and others (e.g., organic acids) may be metabolized,
lowering the volatilization.
The readily decomposable organic constituents will be rapidly
utilized by microorganisms. Of the materials remaining, humuslike
substances become a part of the humus complex of the soil .(Dorr,
1965). The ultimate accumulation of organic constituents in the
soil, however, will be only a small fraction of the total organic
material applied to the land. Salter and Schollenberger (1939) indi-
cated that the beneficial physical effects on the soil of adding
manure are probably overestimated.
There is a considerable backlog of information on the applica-
TABLE 17.11. Corn yield of three varieties with manure and fertilizer on
sandy clay loam.
Variety
Treatment
(N 4- P.O5 + K;O) AES704 C103XB14 WF9XB14
(Ib/a) (bu/a)
159 143
168 144
154 144
(Ib/a)
(1) 1240 -f 730 -f 1030 .............. 147
(2) 1270 -f 750 + 600 -f 66 T manure . . 143
(3) 800 + 515 -f 600 + 66 T manure . . 141
Source: Unpublished data, D. G. Woolley and L. R. Frederick (1960).
Note: Nos. 1 and 3 have comparable amounts of N, P, K.
-------
CHAPTER 17 / MANURE DECOMPOSITION IN SOIL / 253
FRESH MANURE
FIG. 17.2. The influence
of manure on the germina-
tion of corn after 5-day in-
cubation at 25° C. The
control was planted in soil
and the other seeds were
planted in fresh manure.
tion of animal waste in small to moderate amounts to the land and
its effect on crops and on the physical, chemical, and biological prop-
erties of the soil (Hastings, 1938; Salter and Schollenberger, 1939).
But there are many unanswered questions in regard to the applica-
tion of large amounts of animal waste to the land, such as the effect
on crop growth and on the pollution of surface and groundwaters.
REFERENCES
Alexander, Martin. 1961. Soil microbiology. New York: John Wiley.
Atkinson, H. J., Giles, G. R., and Desjardins, J. G. 1954. Trace
element content of farmyard manure. Can. J. Agr. Sci. 34:76-80.
-------
254 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
Burnett, W. E., and Dondero, N. C. 1969. The microbiology and
chemistry of poultry waste decomposition and associated odor
generation. (Mimeo.) Presented Cornell Animal Waste Man-
agement Conf., Syracuse, N.Y., 13-15 Jan. 1969.
Burroughs, A. L. 1967. Viral respiratory infection in commercial
feedlot cattle. Am. J. Vet. Res. 28:365-71.
Commoner, Barry. 1968. Threats to the integrity of the nitrogen
cycle: nitrogen compounds in soil, water, atmosphere, and
precipitation. (Mimeo.) Presented Ann. Meeting Am. Assoc.
Advan. Sci., Dallas, Tex., 26 Dec. 1968.
Crampton, E. W., and Harris, L. E. 1969. Applied animal nutrition.
2nd ed. San Francisco: W. H. Freeman.
Dale, A. C., and Day, D. L. 1967. Some aerobic decomposition prop-
erties of dairy cattle manure. Trans. Am. Soc. Agr. Engrs.
10:546-48.
Dorr, R. 1965. The characterization of the organic substance in
manures. II. Groups of organic manures and residues, and a
proposed scheme of a simple analysis based on the oxidizable
carbon. Landwirtsch. Forsch. 18:238-46. (#10096, Biol.
Abstr., 1968)
Embleton, T. W., and Jones, W. W. 1956. Manure as a source of
nitrogen. Calif. Agr. 10:14-15.
Geldreich, E. E., Bordner, R. H., Huff, C. B., Clark, H. F., and Kabler,
P. W. 1962. Type distribution of coliform bacteria in the feces
of warm-blooded animals. /. Water Pollution Control Federation
34:295-301.
Gilbertson, C. B., McCalla, T. M., Ellis, J. R., Cross, O. E., and Woods,
W. R. 1970. Beef feedlot wastes: characteristics of runoff,
solid wastes and nitrate movement on dirt feedlots as affected
by animal density and feedlot slope. /. Water Pollution Control
Federation. (Submitted.)
Hastings, Stephen H. 1938. Influence of farm manure on yields
and sucrose of sugar beets. USDA Tech. Bull. 614.
Hemingway, R. G. 1961. The mineral composition of farmyard
manure. Empire J. Exptl. Agr. 29:14—18.
Jansson, S. L. 1960a. On the properties of organic manures. I.
Actual humus properties. Uppsala Lantbrukhogsholans Ann.
26:51-75.
. 1960b. On the properties of organic manures. III. Potential
humus properties. Uppsala Lantbrukhogsholans Ann.
26:135-72.
Jenkinson, D. S. 1965. Studies on the decomposition of plant ma-
terial in soil. I. Losses of carbon from 14C-labelled ryegrass
incubated with soil in the field. /. Soil Sci. 16:104-15.
. 1966. Studies on the decomposition of plant material in soil.
II. Partial sterilization of soil and the soil biomass. /. SoiZ Sex.
17:280-302.
King, N. B. 1957. The survival of Brucella abortus in manure. /.
Am. Vet. Med. Assoc. 131:349-52.
Klein, D. A., and Casida, L. E., Jr. 1967. E. coli die-out from normal
soil as related to nutrient availability and the indigenous micro-
flora. Can. }. Microbiol. 13:1461-70.
Lipper, R. I. 1969. Design for feedlot waste management—history
and characteristics. Presented at seminar, Design for Feedlot
Waste Management, Topeka, Kans., 23 Jan. 1969.
Loehr, Raymond C. 1968. Pollution implications of animal wastes—
-------
CHAPTER 17 / MANURE DECOMPOSITION IN SOIL / 255
a fonvard-oriented review. U.S. Dept. Interior, Fed. Water Pol-
lution Control Admin., Robert S. Kerr Water Res. Center, Ada,
Okla.
McCalla, T. M., and Haskins, F. A. 1964. Phytotoxic substances
from soil microorganisms and crop residues. Bacterial. Rev.
28:181-207.
McCalla, T. M., and Viets, F. G., Jr. 1970. Chemical and microbial
studies of ivastes from beef cattle feedlots. Nebr. Exp. Sta. Publ.
(In press.)
McCalla, T. M., Ellis, J. R., Gilbertson, C. B., and Woods, W. R.
1969a. Chemical studies of runoff from rain and snowmelt
from beef cattle feedlots. Agron. Abstr., pp. 84-85.
McCalla, T. M., Ellis, J. R., and Woods, W. R. 1969b. Changes in
the chemical and biological properties of beef cattle manure
during decomposition. Bacterial. Proc., pp. 4—5.
McCoy, Elizabeth. 1967. Lagooning of liquid manure (bovine):
bacteriological aspects. Trans. Am. Soc. Agr. Engrs. 10:784-85.
. 1969. Removal of pollution bacteria from animal waste by
soil percolation. (Mimeo.) Paper £69-430, presented at the
Ann. Meeting of the Am. Soc. Agr. Engrs., Lafayette, Ind.,
22-25 June 1969.
Megie, Christian A., Pearson, R. W., and Hiltbold, A. E. 1967.
Toxicity of decomposing crop residues to cotton germination
and seedling growth. Agron. J. 59:197-99.
Morrison, S. M., Grant, D. W., Nevins, M. P., and Elmund, K. 1969.
Role of excreted antibiotic in modifying decomposition of
feedlot waste. (Mimeo.) Paper presented at the Cornell Animal
Waste Management Conf., Syracuse, N.Y., 13-15 Jan. 1969.
Perkins, H. F., Parker, M. B., and Walker, M. L. 1964. Chicken
manure—its production, composition, and use as a fertilizer.
Ga. Agr. Exp. Sta. Bull. N.S. 123.
Polheim, P. 1965. Characterization of the organic matter in ma-
nures. I. Classification of organic manures on the basis of
solubility of organic substances and of nitrogen in organic bond.
Landwirtsch. Forsch. 18:228-37. (#10099, Biol. Abstr.; 1968)
Rothwell, D. F. 1955. The influence of temperature and nitrogen
on the decomposition of plant materials mixed with soil. Ph.D.
thesis. Purdue Univ. Library.
Salter, Robert M., and Schollenberger, C. J. 1939. Farm manure.
Ohio Agr. Exp. Sta. Bull. 605.
Stewart, B. A., Viets, F. G., Jr., Hutchinson, G. L., Kemper, W. D.,
Clark, F. E., Fairbourn, M. L., and Strauch, F. 1967. Distribu-
tion of nitrates and other water pollutants under fields and
corrals in the middle South Platte valley of Colorado. USDA,
ARS 41-134.
Taiganides, E. P., and Hazen, T. E. 1966. Properties of farm ani-
mal excreta. Trans. Am. Soc. Agr. Engrs. 9:374—76.
Wadleigh, Cecil H. 1968. Wastes in relation to agriculture and
forestry. USDA Misc. Publ. 1065.
Waksman, Selman A. 1938. Hinnus. 2nd ed. Baltimore: Williams
and Wilkins.
Witzel, S. A., McCoy, E., Polkowski, L. B., Attoe, p. J., and Nichols,
M. S. 1966. Physical, chemical and bacteriological properties
of farm wastes (bovine animals). In Proc. Symp. Management
of Farm Animal Wastes, pp. 10-14.
-------
CHAPTER EIGHTEEN
MANURE TRANSFORMATIONS
AND FATE OF DECOMPOSITION
PRODUCTS IN WATER
ROSS E. McKINNEY
HEN animal manure is mixed with water, the biochemical
reactions are both rapid and predictable. The keys to the chemical
transformations in aqueous suspension of manures lie in the chemi-
cal composition of the manures, the microbes present, the environ-
mental conditions, and the time of exposure. It is important to under-
stand each of these major variables and their interactions. Too cften
engineers and scientists examine only a portion of the problem and
fail to recognize the fundamental concepts that underlie all manure
transformations in water.
CHEMICAL CHARACTERISTICS OF MANURES
The chemical characteristics of manure are primarily dependent
upon the chemical characteristics of the feed processed through the
animals. Only a small fraction of the feed eaten by any animal is
processed into animal tissue. The feed is transformd internally into
materials which can be either absorbed or passed through the animal.
Waste products of metabolism are largely collected in the urine and
are passed out of the animal along with the solid manure.
Not very much research has been carried out correlating the
chemical characteristics of feed and the chemical characteristics of
manure, yet a major part of the problem in evaluating the chemical
characteristics of manure lies in knowledge of the chemical varia-
tions in feeds. With hogs, approximately 30% of the feed consumed
is converted to animal tissue and 70% is excreted in the form of
urine and manure (Irgens and Day, 1965). With cattle, the conver-
sion rate is lower, approximately 10%. With a feed consumption of
5.0 Ib/day for a 100-lb hog, the manure should contain 3.5 pounds of
the feed along with the excess water, which will be approximately 1
gallon. This would indicate that hog wastes should contain 300,000
Ross E. McKiNNEY is Professor, Department of Civil Engineering,
University of Kansas.
256
-------
CHAPTER 18 / MANURE TRANSFORMATIONS IN WATER / 257
mg/1 total solids. Generally, additional wasted water results in lower
values of solids than indicated. It is important that complete mate-
rial balances be made to determine the fate of all materials fed to the
animal. It may well be that attention to the complete animal system
could result in more efficient feeds and lower manure productions.
Interest in animal manure pollution problems has stimulated
interest in chemical analysis of manures with respect to water pollu-
tion parameters. A recent study on hog manure (Schmid and Lip-
per, 1969) indicated that the volume of urine and manure should be
approximately 0.9 gal/day/100 Ib live weight for hogs in confine-
ment fed a sorghum-grain-soybean meal ration. The COD of the ma-
nure was 0.52 lb/day/100 Ib live weight, while the BODU was 0.20
lb/day/100 Ib live weight. A review of published data (McKinney
and Bella, 1968) indicated an ultimate BOD of 0.50 lb/day/100 Ib
live weight. There is no doubt that variation in feed composition is
a significant factor in the variation in manure characteristics.
Beef cattle manure collected at the University of Wisconsin
(Witzel et al., 1966) yielded 1.0 Ib BODr/day/1,000 Ib live weight and
3.3 Ib COD/day/1,000 Ib live weight. Since cattle tend to be fed more
varied rations than hogs, the chemical characteristics of the manure
will also be more varied.
MICROORGANISMS
Manure contains a tremendous population of microorganisms.
Unfortunately there have been few studies to delineate the various
types of microorganisms in manure. Beef cattle being rumen orga-
nisms have a more complex microbial flora than hogs. One of the few
studies (McCoy, 1967) on beef cattle manure indicated a wide variety
of bacteria related to the feed consumed by the cattle. As expected
there were proteolytic microorganisms, lactic acid producers,- as well
as cellulose and pectin fermenters. The presence of methane-produc-
ing bacteria has been well established in cattle manure. Special mi-
crobial techniques are required to enumerate the rumen bacteria due
to the anaerobic environment in the rumen and the varied metabolic
characteristics of these microorganisms.
It suffices to say that the microbial population in animal manure
is more than adequate to bring about the chemical transformations
which will occur when the manure is mixed with water.
ENVIRONMENTAL CONDITIONS
Anaerobic Environment
When manure is mixed with water, microbial activity is very
rapid. The oxygen is removed so quickly that it has no significant
effect on the anaerobic bacteria which were growing in the manure
prior to its discharge from the animal. The complex organics are hy-
drolyzed further to yield organic acids from proteins and cellulose.
-------
258 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
The ammonia released from the protein helps prevent the pH from
dropping too rapidly. But as the cellulose is decomposed, the pH
can drop sharply, causing the environment to retard further bacterial
action. As the pH drops below 5.5, microbial activity slows and only
the acid-forming bacteria continue metabolism. Eventually the acid
buildup will cause all microbial activity to cease. The acidified ma-
nure will remain stable until the acids are either removed or neutral-
ized. If the acidified manure is agitated, numerous odorous com-
pounds will be discharged from the liquid phase.
If the pH of the manure does not drop below 6.0, the methane
bacteria will metabolize the organic acids, producing a satisfactory
environment for further metabolism. The ammonia released from
protein metabolism reacts with carbon dioxide to form ammonium
bicarbonate, which acts as a buffer to held the pH at a favorable level.
Under these conditions the acid-forming bacteria continue to metabo-
lize the complex organics, forming organic acids which are immedi-
ately neutralized by the ammonium bicarbonates. The neutralized
acids are metabolized by the methane bacteria to reform the ammo-
nium bicarbonate buffer. The nonbiodegradable organics remain un-
touched.
The extent of degradation of organic matter by the acid-produc-
ing bacteria and the methane bacteria depends largely upon the time
of contact and the extent of mixing. These two environmental fac-
tors are very important in determining the extent of metabolism.
There is no simple formula for determining the time of contact for
metabolism to be carried to completion. It suffices to say that the
more microbes present, the higher the temperature, and the better
the mixing, the shorter will be the time for metabolism. There are
basic limits to this concept. The amount of organic food present will
limit the maximum microbial population which can be maintained.
Temperatures above 37° C will become toxic to the mesophilic bac-
teria and will require the development of thermophilic bacteria ,if me-
tabolism is to continue. Generally it is not possible to obtain too
much mixing but it should be recognized that little additional benefit
can be derived from mixing above the optimum level.
One of the most critical environmental factors affecting anaero-
bic metabolism has been shown to be toxicity related to soluble ca-
tions (McCarty and McKinney, 1961). It was demonstrated that am-
monium ions were toxic to the methane bacteria in anaerobic diges-
tion systems. Since animal urine contains considerable amounts of
urea which is readily hydrolyzed to form ammonium ions, ammon-
ium ion toxicity should be an important factor in the complete anaero-
bic metabolism of concentrated manures. This fact has been con-
firmed recently (Schmid and Lipper, 1969) in studies on controlled
anaerobic digestion of hog manure.
It. should be recognized that the acid-forming bacteria merely
hydrolyze the biodegradable components of i^e organic manures.
There is no change in the COD or the BOD of the wastes. If the ma-
nure contains large quantities of inert, nonbiodegradable materials,
there will be little apparent change. BOD and COD reductions occur
when the methane bacteria convert the soluble organics to methane,
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CHAPTER 18 / MANURE TRANSFORMATIONS IN WATER / 259
an insoluble gas that is discharged to the atmosphere above the liq-
uid. If the methane were not lost from the liquid phase, there would
be no decrease in COD or BOD of the system, only transformation of
the biodegradable organics from one form to another form.
If the water diluting the manure contains nitrates or sulfates, the
bacteria will reduce the nitrates to nitrogen gas while oxidizing the
organic matter or will reduce the sulfates to sulfides. Nitrogen gas
dees not create a BOD or COD and would result in stabilization of the
organic matter. On the other hand, the hydrogen sulfide would exert
an oxygen demand unless it was lost to the atmosphere. It should be
recognized from an energy standpoint that microbes will reduce ni-
trates completely before reducing sulfates (McKinney and Conway,
1957). Both nitrates and sulfates will be reduced before methane will
be formed. This relationship is very important in understanding
anaerobic transformations.
Aerobic Environments
In an aerobic environment free dissolved oxygen is present for
the microbial reactions. Initially the organic matter is oxidized to car-
bon dioxide, water, and ammonia. The oxidation reaction results in
energy transfer from the manure to the microbial cells. The microbes
use this energy to synthesize new microbial protoplasm. Aerobic me-
tabolism results in approximately one-third of the organic matter me-
tabolized being oxidized and two-thirds of the organic matter being
converted to cellular protoplasm.
With true aerobic conditions the bacteria growth stimulates the
growth of protozoa. Like the bacteria, the protozoa oxidize a definite
amount of organic matter while converting a portion of the organic
matter to new protozoan cells. The protozoa use bacteria as their
source of food, thereby reducing the total amount of bacteria in the
liquid.
As long as dissolved oxygen remains in the liquid the bacteria
will metabolize all of the biodegradable organics contained in the
manure. The metabolism of the protein components produces am-
monium bicarbonate which holds the pH at the proper level, between
6.5 and 8.5, for good bacterial growth. If sufficient time is allowed,
nitrifying bacteria will grow and oxidize the ammonium ions to ni-
trites and then to nitrates. Since this reaction results in the conver-
sion of a base to an acid, there will be a definite pH drop. The degree
of pH drop depends primarily upon the amount of buffer present that
is not related to ammonium ions. If oxygen should become limiting
after nitrification has occurred, denitrification will result. The bac-
teria metabolizing the organic manure will use nitrates almost as
readily as oxygen and will reduce the nitrogen gas. Denitrification is
as odorless as aerobic metabolism since metabolism is complete.
One of the major problems in aerobic metabolism of animal ma-
nure is supplying sufficient oxygen to maintain the aqueous system
aerobic. This can be done only with dilute aqueous suspensions of
manure. Failure to maintain aqueous manure systems aerobic has
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260 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
caused numerous problems in trying to arrive at satisfactory aerobic
treatment systems. Dilution can be carried out by the addition of
fresh water or by the use of treated effluent.
The aqueous suspension of manure after aerobic metabolism
will contain the bacteria produced from the metabolic reactions as
well as the inorganic salts in the urine and in the manure and the
nonbiodegradable organics, both suspended and dissolved. The bac-
teria will undergo endogenous metabolism with time until only an
inert residual of dead cells will remain. The inert residual of dead
cellular solids will contain about one-fifth of the volatile solids in the
original microbial mass produced and all of the in organic solids in the
original microbial mass. Thus it is that neither aerobic nor anaerobic
metabolism will result in complete degradation of manure in aqueous
systems. Yet, microbial transformations can convert unstable manure
which is difficult to handle into a fluid material which is easy to
handle and contains all of the elements in the original manure. This
permits easier spreading of treated manures onto fields without the
creation of obnoxious odors and nuisance conditions.
AQUEOUS TREATMENT SYSTEMS
There is no doubt that mixing animal manures with water will
result in serious environmental pollution problems as a result of un-
controlled microbial reactions which will be predominantly anaerobic.
For this reason it is necessary to develop systems which employ con-
trolled microbial reactions in order to transform the manure into a
form where it can be returned into the environment without creating
a serious pollution problem. A number of aqueous treatment systems
have been developed and studied to date.
Oxidation Ponds
The simplest form of liquid treatment for animal manures is the
oxidation pond. In all respects, oxidation ponds have not proved suc-
cessful for animal wastes. Oxidation ponds have tended to produce
obnoxious odors and poor quality effluents (Clark, 1965; Hart and
Turner, 1965).
Fundamentally, there is no reason why oxidation ponds could
not be used to treat animal manures satisfactorily. The problem lies
in use of inadequate dilution of the concentrated manures. Generally,
animal manure lagoons are designed to operate on minimum water
volumes in order to eliminate any effluent. The net result is that con-
centrated manure is discharged at a single point in the oxidation
pond. The heavy manure solids tend to settle out around the inlet,
creating an anaerobic environment at a single point. The building
up of solids results in an acid environment due to anaerobic metabo-
lism and failure to distribute the acids into the liquid so that methane
fermentation can occur. Anaerobic metabolism also results in carbon
dioxide formation. The carbon dioxide is released as a gas as acids
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CHAPTER 18 / MANURE TRANSFORMATIONS IN WATER / 261
build up and depress the pH. The carbon dioxide gas causes solids to
rise to the surface and permits odorous compounds to be released
into the environment.
The important concept to recognize in the use of oxidation ponds
is dispersion of the organic matter throughout the pond liquid. It
must be recognized that simple oxidation ponds cannot be used for
animal manures. There is no way for the manure to be dispersed in
a simple pond system. It is possible to use a large pump to dilute the
manure prior to its addition to the oxidation pond. The treated efflu-
ent could be used to flush the manure from the animal house. Un-
fortunately, the quantity of liquid which would have to be recycled
is quite large, around 200 gallons per day per hog or 1,000 gallons
per day per steer.
It is essential that there is adequate volume in the oxidation pond
for good metabolism. A 4-foot deep oxidation pond can handle
around 40 Ib BOD-/acre/day. This would require 1 acre of oxidation
pond for 200 hogs or 40 steers. For either confined hog growing or
cattle feedlots, the use of oxidation ponds requires far too much land
area. A 50-sow farrowing house would require 0.3 acres of oxidation
ponds to treat the wastes, provided there was good mixing. Larger
installations create even greater problems due to mixing.
Aerated Lagoons
Mechanical aerators have been added to oxidation ponds in an
effort to produce better mixing and to add additional oxygen. In an
effort to reduce power costs to a minimum, the mechanical aerators
are generally undersized for the pond volume. Best results are ob-
tained when mixing relationships are balanced against oxygen trans-
fer characteristics. Some research (McKinney and Benjes, 1965)
indicated that a mechanical surface aerator was capable of trans-
ferring 1.5 pounds of oxygen per HP-hr with a residual DO of 1.0
mg/1 and that 14 HP was required to reproduce good mixing in 1,000
cu ft of pond volume. This meant that a 5-HP surface aerator could
transfer 7.5 pounds of oxygen per hour and mix 20,000 cu ft of
wastes. The 5-HP surface aerator could treat the wastes from 225
hogs or 45 head of cattle. The very long detention time, over 50 days.
would result in a high degree of stabilization of the BOD but would
still produce a large mass of solids for disposal.
Oxidation Ditch
One of the most effective forms of the aerated lagoon concept
has been the use of the oxidation ditch under a slotted floor. Mechan-
ical rotor aerators circulate the wastes under the slotted floor and
aerate the mixture. The aerobic environment results in stabilization
of the manure in an odor-free environment. Although the concept of
the oxidation ditch was originally tried in Europe, the first successful
field scale unit for treating animal wastes in the United States was
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262 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
put into operation at the Paul Smart hog farm near Lawrence, Kansas,
in January 1966. The results obtained from the study of several units
(McKinney and Bella, 1968) indicated that mechanical rotor aerators
were capable of treating the wastes from up to 275 hogs with a 5-HP
unit. This would mean that the same unit could treat the wastes
from 55 head of cattle.
Foaming has been a serious problem in starting oxidation ditches
as well as in improperly loaded units. A number of investigators
(Sheltinga, 1966; Moore et al., 1969) have reported foaming problems.
Aside from start-up, foaming occurs only when the unit is overloaded.
Maintenance of proper aerobic conditions with adequate mixing elim-
inates foaming due to the manure. Excessive use of detergents or
disinfectants could result in foaming but this would occur only under
abnormal conditions. Foaming should never be a problem in a well-
operated treatment unit.
The oxidation ditch system is capable of metabolizing all of the
biodegradable components of the manure but normally will contain a
large quantity of living microbial cells which would exert a hi eh oxy-
gen demand, around 1,000 mg/'BOD-. These microbial cells can be
further treated by oxidation ponds or mixing with soil. Further
aeration alone will also result in their stabilization.
Anaerobic Lagoons
Recently it has been shown that properly designed anaerobic la-
goons can be used for pretreatment of manure. Field units for hogs
(Curtis, 1966; Willrich, 1966) indicated 100 cu ft of anaerobic la-
goon per 100-lb hog. By and large the anaerobic lagoons were merely
large sludge-holding ponds. Periodically solids were removed and
placed on the land. An anaerobic lagoon for dairy cattle (Lrehr and
Ruf, 1968) operated at 9 Ib BOD,-/day/l,000 cu ft. Cattle-waste
anaerobic lagoons have been operated at higher organic loadings than
hog-waste lagoons as a result of the nature of the wastes. Cattle
wastes generally have a higher population of methane bacteria and a
better buffering capacity. This generally permits cattle-waste lagoons
to operate more efficiently. The problem with efficient operation of
anaerobic lagoons lies in adequate mixing. Gas production by the
methane bacteria alone will not produce the desired degree of mixing
as heavy organic loads and untreated solids will accumulate in the
anaerobic lagoon. It should be recognized that anaerobic treatment
of cattle manure will result in only 20% total solids reduction. While
the lagoon system will remove 80 to 85% of the solids, the accumu-
lated solids must be removed eventually.
Concentration of solids to 10% would require approximately
one-half cu ft per day per head of cattle for sludge storage alone.
It is important that sludge storage be provided for a period of 6
months to a year to reduce the time intervals for sludge removal. In
effect, sludge storage capacity should equal the active anaerobic
lagoon capacity for beef cattle.
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CHAPTER 18 / MANURE TRANSFORMATIONS IN WATER / 263
EVALUATION OF AQUEOUS TREATMENT SYSTEMS
With regard to aqueous treatment systems for animal manure, it
is apparent that aqueous treatment systems are not desirable for
animal wastes except in special situations. The concentrated animal
wastes are not normally mixed with water and can be handled best
as solid wastes. This is especially true of cattle manure.
The advent of confined animal growing has posed some changes
in the philosophy of handling manure as a solid waste. Chicken
houses have been designed to collect manure as a solid on moving
belts and to transport it from the source to a point of concentration.
On the other hand, confined hog houses have too much fluid manure
for handling as solids. The oxidation ditch has proved a satisfactory
system for both collection and treatment of hog manure; it is de-
signed to replace conventional collection and disposal methods. It
should be recognized that the treated hog manure must be returned
to the soil the same as untreated manure. The soil is the ultimate
acceptor of all animal wastes. It is vital that this concept be acknowl-
edged and accepted as one of the basic factors in manure disposal.
Studies are currently underway to demonstrate the use of the
oxidation ditch for handling cattle manure from animals grown in
confinement like hogs. There is no reason why it should not work.
Regardless of the treatment system used, the biological treat-
ment will reduce only a small fraction of the total solids of the ma-
nure. The residual solids and the soluble salts pose a major disposal
problem that must be considered as part of the total manure disposal
problem. Fortunately, biological treatment of the manure destroys
the obnoxious qualities and results in a material which can be han-
dled relatively easily without the creation of sanitary problems.
REFERENCES
Clark, C. E. 1965. Hog waste disposal by lagooning. /. Sanit. Eng.
Div. Am. Soc. Civil Engrs. 91 (SAG): 27-41
Curtis, D. R. 1966. Design criteria for anaerobic lagoons for swine
manure disposal. In Management of farm animal ivastes. Am.
Soc. Agr. Engrs. Publ. SP-0366, pp. 75-80.
Hart S. A., and Turner, M. E. 1965. Lagoons for livestock manure.
J. Water Pollution Control Federation 37:1578-96.
Irgens, R. L., and Day, D. L. 1965. Laboratory studies of aerobic
stabilization of swine wastes. Farm structures eng. rept. Univ.
of 111. Agr. Exp. Sta.
Loehr, R. C., and Ruf, J. A. 1968. Anaerobic lagoon treatment of
milking-parlor wastes. /. Water Pollution Control Federation
40:83-94.
McCarty, P. L., and McKinney, R. E. 1961. Salt toxicity in anaerobic
digestion. /. Water Pollution Control Federation 33:399-415.
McCoy, E. 1967. Lagooning of liquid manure (bovine): bacterio-
logical aspects. Trans. Am. Soc. Agr. Engrs. 10:784-85.
iMcKinney, R. E., and Bella, R. 1968. Water qualitij changes in con-
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264 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
fined hog ivaste treatment. Kans. Water Resources Res. Inst.
Rept. Univ. of Kans.
McKinney, R. E., and Benjes, H. H., Jr. 1965. Evaluation of two
aerated lagoons. /. Sanit. Eng. Div. Am. Soc. Civil Engrs.
91 (SA6): 43-55.
McKinney, R. E., and Conway, R. A. 1957. Chemical oxygen in bio-
logical waste treatment. Sewage Ind. Wastes 29:1097-1106.
Moore, J. A., Larson, R. E., and Allied, E. R. 1969. Study of the use
of oxidation ditch to stabilize beef animal manure in cold cli-
mates. In Animal ivaste management, pp. 172—77. Cornell
Univ.
Scheltinga, H. M. 1966. Biological treatment of animal wastes. In
Management of farm animal wastes. Am. Soc. Agr. Engrs. Publ.
SP-0366, pp. 140-43.
Schmid, L. A., and Lipper, R. I. 1969. Swine waste characterization
and anaerobic digestion. In Animal ivaste management, pp.
50-57. Cornell Univ.
Willrich, T. L. 1966. Primary treatment of swine wastes by la-
gooning. In Management of farm animal wastes. Am. Soc.
Agr. Engrs. Publ. SP-0366, pp. 70-74.
Witzel, S. A., McCoy, E., Polkowski, L. B., Attoe, O. J., and Nichols,
M. S. 1966. Physical, chemical and bacteriological properties
of farm wastes (bovine animals). In Management of farm ani-
mal wastes. Am. Soc. Agr. Engrs. Publ. SP-0366, pp. 10-14.
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CHAPTER NINETEEN.
DISEASE TRANSMISSION
OF WATER-BORNE ORGANISMS
OF ANIMAL ORIGIN
STANLEY L. DIESCH
V*ENTURIES prior to the era of bacteriology, man realized
that water was somehow involved in the transmission of disease.
Before consideration of current problems of disease transmis-
sion related to water, the historical implication of water and disease
will be briefly reviewed. The early miasmatic theory of disease
taught that all disease was due to emanations from water, earth, and
influence of the stars, moon, winds, and seasons. More than 2,500
years ago during the pre-Christian era, the role of water was further
described by Hippocrates, the "father of medicine," in his treatise,
"Airs, Waters and Places" (Chadwick and Mann, 1950). He related
causes of disease to different waters, the wind, and to the slope of
the land. These findings were further advanced during the early
Christian period and the Middle Ages. During this time epidemics
of certain diseases such as typhoid and cholera were associated with
floods and the rise and fall in the level of groundwater. The
theory of poisonous miasmata and vapors (arising from decaying
filth) held until the end of the nineteenth century. Some early
observations were inadequate and unsound, but others represented
correct observations of fact.
During the nineteenth century, researchers, including Henle,
Snow, Budd, and Pasteur, developed the germ theory of disease. In
1876 Robert Koch proved the germ theory by his classical work on
anthrax. Historical aspects of bacteriology are well described in a
book by Bulloch (1938). The golden era of bacteriology has existed
and developed for nearly 100 years. Major emphasis has been on
the importance of the microbiologic agent in causation of com-
municable diseases.
Recognition that predisposing or contributing factors of disease
must be identified, and multiple causes of disease ex;st, has
broadened man's efforts to consider the total perspective of disease—
the interrelationship of the agent, host, and environment complex.
STANLEY L. DIESCH is Associate Professor, Department of Veterinary
Microbiology and Public Health, University of Minnesota.
265
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266 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
CONCEPTS OF DISEASE TRANSMISSION
Knowledge of epidemiology as related to disease transmission
is essential. Epidemiology is the study of disease as related to the
host, agent, and total environment—or the ecology of disease.
Of the many infectious diseases affecting animals, more than
150 are classified as zoonoses, or those infections or infectious dis-
eases transmitted under natural conditions between vertebrate ani-
mals and man (WHO, 1967b). Zoonoses associated with food-
producing animals are usually considered occupational. An increas-
ing number of zoonotic diseases associated with recreational activi-
ties are being reported.
The infectious disease process contains six necessary factors.
These factors are considered as links in a chain and all are essential
in disease development. The six essential factors are as follows:
1. Causative or etiological agent
Infection represents entry and development or multiplication
of an infectious agent in the body of man or animal. The para-
sitic agent usually lives at the expense or detriment of the host.
Fortunately, many organisms are not pathogenic for man and
animals. Certain organisms have specificity and will infect only
a selected species. For example, hog cholera virus will not infect
man or other animals.
2. Reservoir of the infectious agent
Reservoirs are man, animals, plants, soil, or inanimate or-
ganic matter. Here an infectious agent lives and multiplies.
With few exceptions, pathogens are not capable of prolonged
growth or multiplication outside the living body. Significance
of the animal reservoir depends upon man's direct or indirect
association. Man has much greater direct exposure to domestic
animals than wild animals. Animals and man are potentially
and indirectly associated with animal pathogens through waters.
Man remains the most significant reservoir of infection for his
species, and animals for their kind.
3. Escape of organisms from the reservoir
Escape and subsequent discharge of the organism into the
environment may occur through natural body openings (respira-
tory, intestinal, urinary), by way of open lesions, and by mechani-
cal means (blood-sucking arthropods). A variation exists in time
duration of escape of pathogens. This is dependent on the course
of disease in the host animal. In general the duration of com-
municability of an infectious agent varies inversely with the
degree of communicability.
4. Transmission of the infection from the reservoir to the new host
Transmission occurs by direct and indirect methods. Direct
contact occurs when organisms pass immediately to the new
host by physical contact. Indirect contact occurs when there is
a transfer of infectious agents between the reservoir and the
new host without direct association. These organisms must be
capable of surviving outside the body and a vehicle or vector
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CHAPTER 19 / DISEASE TRANSMISSION / 267
must transfer the organisms. The classification of indirect meth-
ods of transmission are vectors (arthropods or other inverte-
brates) and vehicles (all nonliving objects or substances that are
contaminated and transfer the infectious organisms). Vehicles
include water, milk, other foods, air, and fomites.
5. Entry of organisms into new hosts
Before entry, the organisms must pass defensive barriers of
the host. With exceptions, the mode of entry into man or animal
corresponds with the mode of exit.
6. Susceptible host
Man and animals possess defense mechanisms or resistance,
which protect against invasion of the pathogenic microorganisms.
Immunity implies the development of absolute protection in a
susceptible host against disease by artificial or natural means.
Development of a disease in man or animal depends on comple-
tion of several concurrent events and includes the strength of the
six essential links of the chain.
The following important factors concern the susceptible host.
Age usually increases resistance, for the longer man or animal lives,
the greater is the opportunity for contact with specific microorga-
nisms and for development of immunity. Incidence of disease in a
community is significant, for greater occurrence of disease increases
opportunities for exposure. Opportunities for spread include biologi-
cal, sccial, and physical factors. Environmental factors such as
water supply, sanitation, housing, and crowding are involved.
The occurrence of disease in populations has been inadequately
reported. Cases (with clinical signs or symptoms) may be reported
but many infected carrier (subclinical or inapparent) animals may
exist in a population. Because the carriers are often not recognized,
they are more capable of transmitting disease to populations. The
case-carrier concept may be viewed as a floating iceberg, with a small
fraction of the ice observed (cases) and the remainder under water
inapparent (carriers). This phenomenon varies with each disease
entity.
If a disease outbreak is manifest in a population, the outbreak
exists until there is a death, disablement, recovery, and/or develop-
ment of resistance against the specific disease. Infected animals
may shed millions of organisms into the environment, and these
organisms may find a susceptible host. Errington (1963) has stated,
"Nature's way is any way that works."
To prevent, control, and eradicate animal disease, treatment
with antibiotics and chemotherapeutics, and prevention by use of
vaccines and bacterins, have been developed. Quarantine, test, and
slaughter programs of identified infected animals have been used.
THE CHANGING ENVIRONMENT OF ANIMALS AND MAN
A few decades ago a predominantly rural America existed with
wide dissemination of livestock populations. The raising of livestock
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268 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
and rural living remain predominant in many areas of the world.
Today, fewer farms have greater concentrations of livestock. In the
United States in 1937, 24.3% of 128,649,000 people lived on farms
containing 94,694,000 animal units. In 1967, 5.4% of 198,608,000
people lived on farms containing 120,439,000 animal units. In three
decades there has been a 21.3% increase in animal units, with a
65% decrease in human farm population and a 35% increase in total
population (USDA, 1968b).
An increasing number of animals are raised in confinement.
In the United States on January 1, 1969, there were 23,040,000 cattle
on feed in lots. Of these, 10,823,000 were found on 2,080 lots, each
with 1,000 or more head of cattle (USDA, 1969). It is not uncommon
to find feedlots of 10,000 cattle or broiler farms of 100,000. This
concentration can greatly enhance disease-prevention programs, but
may by increased contact cause greater problems in disease trans-
mission.
The environment of the agricultural worker allows greater ex-
posure to infectious and parasitic diseases than is encountered in
urban surroundings (WHO, 1962).
As man migrated from the farms to the cities, controlled sewage
disposal and chlorination of water supplies have reduced the in-
cidence of illnesses such as typhoid fever, paratyphoid, dysenteries,
and cholera. Perhaps man, as a result of control of specific water-
borne diseases, has developed a placid attitude concerning water-
associated disease.
Living in the city, man has increasingly been seeking his out-
door recreational activities in rural areas. Most people seeking
outdoor recreation wish to be near water. Swimming will be the most
common form of outdoor recreation by the year 2000 (U.S. Outdoor
Recreation Res. Rev. Comm., 1962). Being exposed to the environ-
ment of domestic and wild animals and surface waters will increase
man's exposure to waterborne infections.
Water is absolutely essential to maintain the bodies of both man
and animal. In the United States much of man's water supply for
household use is from deep wells or chlorinated, treated supplies.
Man continues to be exposed to surface water through occupational
and increasing recreational activities. Confined animals receive
much of their water from deep wells, but those on ranges in pasture
largely consume water from ponds, streams, rivers, and lakes.
Economics of agriculture demands the fullest utilization of land.
Often land adjacent to surface water can be used only for pasturing
of livestock. Millions of food-producing and wild animals are found
here. If infected, pathogens escape into surface waters via respira-
tory discharges, drainage of wounds, feces or urine, or dead animals.
Transmission of organisms from reservoir to water also occurs by soil
runoff, flooding, wind, and other ways. Due to the dilution, patho-
gens discharged into water may be of relatively low densities. The
general concept that running water undergoes purification is counter-
acted by the fact that infected animals may shed millions of patho-
gens for days, weeks, or months.
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CHAPTER 19 / DISEASE TRANSMISSION / 269
TRANSMISSION OF DISEASE
In consideration of agriculture's role in maintaining clean
water, concern is for the cause and effect or the effect and cause
relationship of waters contaminated with pathogenic organisms.
When total ecology of disease is studied, complexity is greatly
increased and by definition decreased by the numerous interrelated
factors involved. To document water's role as a vehicle in disease
transmission, information gathered from a literature review will be
used. Specific disease entities are grouped by classification based on
etiology of the causative organism.
In view of the scope of this subject it will be impossible to
discuss all diseases individually. No reference will be made to pre-
vention, control, and treatment. This information is available in
literature cited. Specific examples in each category are briefly
described, with emphasis on resistance and transmission of the
agent.
INFECTIOUS DISEASES OF ANIMALS AND MAN
Bacterial Diseases
Species of vegetative bacteria vary greatly in their ability to
survive away from the host. Spore forms are very resistant to physi-
cal and chemical agents whose action can greatly affect the growth
rate and death (Merchant and Packer, 1967).
In 1854 water first assumed an important role in the transmis-
sion of disease when John Snow was able to demonstrate the rela-
tionship between human cholera and water from the Broadstreet
pump in London. Since the development of the bacteriologic era,
numerous documentations of wrater transmission of disease have
been made.
SALMONELLOSIS
In the United States the major zoonotic disease is salmoiiellosis.
Approximately 20.000 human cases are reported each year, but
estimates are that between 1 to 2 million cases occur (Steele, 1968).
The disease is widespread in food-producing animals, poultry, and
other animals (Edwards and Galton, 1967). These are the major
reservoirs for man. In acute cases in calves, 10,000,000 organisms
per gram of feces have been reported.1
Salmonella survive in water and the environment for extended
periods of time (Kraus and Weber, 1958; Andre et al., 1967; Gibson,
1967). The bacteria could survive several weeks to 3 months in
drinking water and natural surface water (Kraus and Weber, 1958).
liibbs and Foltz in 1964 isolated Salmonella from two calves, creek
water, and a human being. Schaal (1963) reported enzootic salmonel-
1, K. L. Loken, 1967, personal communication.
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270 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
losis in cattle as a result of drinking contaminated brook water. In
May 19135 a serious epidemic of waterborne Salmonella typhimurium
occurred, with three human deaths (NCDC, 1965). Of the human
cases reported each year, more than half are sporadic. The re-
mainder are associated with epidemics that can usually be traced
to contaminated foods of animal origin or to water (McCroan et al..
1963; Steele, 1968).
More than 1,300 serotypes of Salmonella have been identified.
These bacteria are ubiquitous and shed in the feces of infected
animals. Surface waters serve as potential vehicles for transmission
of Salmonella to other animals or man.
In 1966 a large waterborne outbreak of human cases occurred
at Riverside, California, from a Snhnonenn-contarninated water
supply. Although the source of contamination was not identified, it
was speculated the water may have been contaminated by seepage
from distant cattle feedlots (Decker and Steele, 1966). Due to the
widespread occurrence of reservoirs and environmental contamina-
tion, salmonellosis continues to be a major disease entity.
LEPTOSPIROSIS
Leptospirosis, caused by a spirochete, has been classified as a
waterborne zoonosis. In the United States and many areas of the
world, leptospirosis is found in domestic animals and wildlife. In
domestic animals the bacteria are found primarily in cattle and
swine and may be shed in the urine for several months. Counts of
100 million leptospires per ml of urine have been reported (Gillespie
and Ryno, 1963).
Leptospires may live in water for several weeks (Chang et al..
1948; Gillespie and Ryno, 1963; Ryu and Liu. 1966). However, the
changing environment may complicate survival (Diesch et al., 1969).
Fresh water in all forms in nature is a major factor in the circulation
of leptospires in enzootic foci. The conventional idea that stagnant
waters and slow-moving streams are potentially infectious is not
necessarily valid. The infectiousness of rapid-flow water in the
jungle and increased infectiousness with flooding has been shown
(WHO, 1967a). Leptospires have been isolated from fast-moving
streams (Gillespie and Ryno, 1963).
Human outbreaks have occurred when people have come in
contact with contaminated water through swimming or occupational
exposure. In the United States since 1941 approximately 1,000
human cases have been reported. Swimming has accounted for 10
outbreaks that involved 233 human cases.2 In 1964 Leptospira
pomona was isolated from the swimming site in a creek where human
cases occurred in 1959 and 1964 following swimming. Cattle and
other animals frequented this stream (Diesch and McCulloch, 1966).
Sixty-one human cases occurred in Washington following swimming
in water contaminated by infected cattle (NCDC, 1965a).
Between 1951 and 1960 the estimated annual loss to the dairy
and milk industry was more than $12 million per year (USDA, 1965).
In 1969 the Leptospirosis Committee of the United States Animal
2. W. F. McCulloch, 1969, personal communication.
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CHAPTER 19 / DISEASE TRANSMISSION / 271
Health Association stated that leptospirosis is not amenable to eradi-
cation. It is likely that water will continue to serve as a vehicle of
transmission of leptospirosis to animals and man and remain one of
the major sporadic diseases associated with water transmission.
ANTHRAX
In addition to being one of the oldest known diseases affecting
man and animals, anthrax was the first zoonotic disease associated
with an etiologic agent.
Anthrax spores are one of the most resistant of pathogenic
bacteria. Spores stored in soil contained in a rubber-stoppered bottle
remained viable for 60 years (Wilson and Russell, 1964). Field ob-
servations indicate similar duration of viability in alkaline, undrained
soils in warm climates (Blood and Henderson, 1968). There have
been instances of animals becoming infected on anthrax areas 25
years after the original cases of disease (Merchant and Packer, 1961).
A major mode of dissemination of spores is by surface \vaters
flooding contaminated ground, causing transfer of spores to wide-
spread areas. Many water courses in anthrax districts in the United
States are contaminated (Stein, 1942; Jones, 1963).
Reported human cases of anthrax have declined steadily during
the past 50 years (Brackman, 1964). Most of the human cases
reported in the United States in recent years have been associated
with imported goat hair and coarse wool. Estimates indicate that
a decade ago the worldwide yearly incidence was 20,000 to 100,000
cases (Classman, 1958).
Animals are most commonly infected by ingestion of contami-
nated food and water. Potential infection will exist for many years,
especially in the contaminated anthrax districts where surface water
plays a major role in transmission.
TULAREMIA
Tularemia is a widespread, highly contagious disease that has
been isolated from more than 100 kinds of wild and domestic animals
(Steele, 1968). In U.S. agricultural animals, the disease is reported
most commonly in sheep. The bacteria do not form spores. Re-
searchers reported water and mud contamination and the occurrence
of tularemia in beaver and muskrat as widespread phenomena in
northwestern United States. The tularemia organism has been found
in all streams tested with any frequency in the Bitter Root Valley
(Hamilton area) of Montana (Parker et al., 1951).
The organisms are believed to be able to multiply in the mud,
leaf mold, and materials that make up the beds and shores of the
streams. The aerobic organism is recoverable from running waters
only, and never found in still or stagnant streams. During a 7-
year period in one stream, Francisella tularensis has been recovered
from approximately 30% of the specimens tested.3
3. Cora R. Owen, 1969, personal communication.
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272 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
Tularemia can be transmitted by many different routes (Shaugh-
nessy, 1963). There is evidence that the bacteria will penetrate the
intact skin (Quan et al., 1956).
Four clinical and four probable human cases were associated
with contaminated water (Jellison et al., 1950). Two of the cases
were associated with contaminated water supply (spring water); the
bacteria of tularemia were isolated from water collected from the
faucet. In another report (Jellison et al., 1942) contamination of
four streams was found. One stream remained contaminated for 33
days after any beavers were known to be present. Since contamina-
tion of water may persist for months and perhaps for years, drinking
of water from streams in endemic regions should be avoided. During
a tularemia epidemic that occurred in Vermont. 47 human cases were
linked to contact with muskrats; the tularemia organism was isolated
from the mud and water of a trapping site (Young et al., 1969). This
was North America's largest outbreak of tularemia in man linked to
aquatic mammals. Since the disease is established in wildlife popu-
lations it does not presently appear amenable to control.
BRUCELLOSIS
Brucellosis is a contagious disease of cattle, swine, and goats
and a major occupational disease of man.
The bacteria are shed in the excretions and secretions, especially
uterine, of infected animals. In pastures and barnyards, brucellae
have survived 65 to 182 days or more in dead fetuses and fetal mem-
branes, and 2 months in manure (Bosworth, 1934). In tap water the
organism remains viable 10 to 120 days at 25° C and in bovine urine
up to 4 days (Van Der Hoeden, 1964). Brucellae survived in grass
for 100 days in winter and 30 days in summer. It survived freezing
temperature over 824 days in cattle urine, lake water, tap water, raw
milk, bovine feces, and soil (Ogarkov, 1962). In the United States,
1975 is the target date for the eradication of brucellosis. According
to Harris (1950), water, except when grossly contaminated with
brucella organisms, seems to be an unlikely source of human in-
fection.
ERYSIPELAS
Erysipelas is of major importance and widely distributed.
causing swine erysipelas and affecting turkeys. The bacteria occa-
sionally cause erysipeloid in man.
The organism is resistant to drying and remains viable a month
or more in the dark and 10 to 12 days in sunlight (Morse, 1963).
It exists in soil as a saprophyte and retains virulence. Persistence
in soil is variable and determined by temperature, pH, and other
factors. It is reported viable 4 to 5 days in drinking water and 12 to
14 days in sewage (Reed, 1965). Soil, food, and water are readily
contaminated by infected animals through large numbers being dis-
charged in the urine. From soil experimentally inoculated, the or-
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CHAPTER 19 / DISEASE TRANSMISSION / 273
ganisms were recovered to a maximum of 21 days. Persistence was
longer during winter and spring (Rowsell, 1958). Surface waters
may transmit the disease from one farm to another (Karlson, 1967a).
Since the bacteria can pass through the stomach without loss of
viability, carrier animals may continuously contaminate the soil
(Rowsell, 1958).
TUBERCULOSIS
Although in the United States bovine tuberculosis is no longer of
major importance, the disease is still of major importance in some
areas of the world.
The bacteria are resistant to chemical and physical agents
(Middlebrook, 1965). In some instances virulent bovine tubercle
bacilli can survive 6 months exposure in soil, in soil-dung mixture,
and in dung (Maddock, 1933). It is reported (Christiansen, 1943;
Blood and Henderson, 1968) that stagnant drinking water may cause
infection up to 18 days after being used by a tuberculous animal.
Viable organisms were isolated from the soil 6 or 8 weeks after feces
were dropped, but the duration varies widely—being longer in wet
weather. According to Karlson (1967b), the bacillus is transmitted
through feed and sometimes water.
In the United States in recent years only a rare human case was
caused by the bovine strain (Feldman, 1963).
TETANUS
The disease is widespread and usually associated with the entry
of the bacteria into a wound. The organism, a sporeformer, is widely
distributed in nature and is abundant in animal or human feces,
especially of horses and other herbivorous animals (Sterne and Van
lieyningen, 1965; Merchant and Packer, 1967). The spore form
resists boiling for more than 1 hour. The spores are capable of per-
sisting in the soil for a number of years (Blood and Henderson, 1968).
With the rapid increase of the horse population in the United States,
the subsequent contamination of the soil will likely increase. Surface
water may play a major role in the dissemination of the tetanus
spores.
COLIBACILLOS1S
Colibacillosis has worldwide distribution and it is, under certain
conditions, associated with enteric infections in man and animals.
It is found universally in the intestinal tracts of man and animals.
The organism is usually destroyed at 60° C for 30 minutes. Heat-
resistant strains may survive (Merchant and Packer, 1967) and in-
dividual cells survive freezing in ice for 6 months. The organism is
transmitted by water, feces, and flies contaminated with fecal
material. Some strains are hazards to both man and animal and may
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274 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
cause illness of the newborn (Morgan, 1965). The number of E. coli
organisms found in water indicate the extent of fecal contamination.
Attempts to document association between cases in agricultural
animals and man appear to be inconclusive.
Rickettsial Diseases
Agents of rickettsial diseases other than Q fever depend on
arthropod vectors for transmission of disease and on human or
animal hosts for their mechanisms (Fox, 1964).
Q FEVER
Q fever is found in man and animals on every continent of the
world. It has a widespread host range (Babudieri, 1959). In the
United States it has agricultural significance in sheep, goats, and
cattle. The organism, an intracellular parasite, has greater resist-
ance to physical and chemical agents than other pathogenic Rickett-
sia and has more resistance than most nonsporogenic bacteria.
The agent is viable in skim milk for 42 months and tap water for 36
months (Ignatovich, 1959). Welsh et al. (1959) isolated the organism
from standing water (surface pools) on infected sheep ranches in
California over a 6-week period during the lambing season, and from
the soil up to 148 days. Stoenner (1964) reported that the role of
microenvironments on mobile fomites was significant in extending
the hazards of the disease to diverse occupational groups not nor-
mally considered at risk. He estimated that in the United States at
least 25% of the dairy herds and a higher percentage of sheep and
goat herds are infected. Q fever usually appears as inapparent in-
fection in domestic livestock.
The exact mode of transmission is unknown but dust-laden air,
containing animal waste, and ticks are considered important. One
organism has been suggested as an infectious dose for man (Tigertt
et al., 1961). The role of water in transmission has not been
determined.
Viral Diseases
There are an estimated 500 known animal viruses (Green,
1965). Counterparts of major groups of viruses known to infect man
are also found in domestic animals. According to Abinanti (1964),
no thorough investigation has been made to determine which virus
may be present in milk and other animal by-products or under what
conditions they are destroyed.
In an extensive review of enteroviruses of animals it was con-
cluded that the enterovirus problem of animals parallels that re-
ported in man and that a multitude of organisms may be isolated
from feces of different animal species (Kalter, 1964). In recognition
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CHAPTER 19 / DISEASE TRANSMISSION / 275
that human health is closely related to health of animals, viruses
are considered the least-explored infectious agents (Sinha et al.,
1960).
In general, viruses do not survive for long periods of time out-
side the animal host (Gratzek, 1967). Viruses possess about the
same degree of resistance to heat, drying, and chemical agents as
many of the vegetative forms of bacteria. Most are unaffected by
concentrations of antibiotics that will destroy bacteria.
According to Frier and Riley (1965), some information on sur-
vival of viruses in water is available, but most of the data have been
obtained from distilled-water studies under controlled temperatures.
They stated that compared to bacterial and protozoal agents, viruses
in natural waters, except under unusual circumstances, are pre-
sumed to survive only for a short period of time. However, Brown
and McLean (1967) stated that enteroviruses are more resistant to
halogens than bacteria and unless residual free chlorine is sufficiently
high, water, although free of viable bacteria, may contain active
virus.
Joyce and Weiser (1965) reported that a study of farm ponds
over a 6-month period revealed no enteroviruses or specific bacterio-
phages. They experimentally inoculated pond water with entero-
viruses which survived for long periods of time (present up to 91
days) at simulated temperature extremes and over pH ranges of
extremes found in natural pond waters. The virus survived longer
in slightly and heavily polluted waters than in moderately polluted
waters. Chemicals found in farm ponds did not appear to inhibit
viral survival. Based on experimental findings, the conclusion was
that farm pond water poses a definite site for storage of enteroviruses.
Less is known regarding the role of water in transmission of
viruses than bacteria. Many of the viral diseases are transmitted by
arthropods. Approximately 200 viruses have been classified as arbo-
viruses (Merchant and Packer, 1967). The nonarthropod-borne viral
diseases are fewer in number but many are associated in the United
States with animal industries.
Many classes of viruses are excreted in the feces of animals.
Included are picornaviruses (enteroviruses), reoviruses (respiratory-
enteric viruses), herpes viruses, adenoviruses, and myxoviruses (Grat-
zek, 1967).
According to Prier and Riley (1965), natural water is of minor
significance when compared with other factors that affect viral
transmission of disease between individuals and herds.
Geldreich (1965), in describing the origin of microbiologic pol-
lution in streams, stated that water contaminated by fecal pollution
may also contain viruses excreted by warm-blooded animals.
Although man is primarily involved in viral hepatitis transmis-
sion, this agent, with high resistance and capable of being trans-
mitted via surface waters, can serve as a study model. Mosley (1963)
reports a total of 31 human epidemics presumed to have been trans-
mitted by water. The hepatitis virus is not destroyed by chlorination
or pasteurization (Anderson et al., 1962). According to Mosley
(1963) only the viral agent of infectious hepatitis has been clearly as-
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276 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
sociated with waterborne transmission in man's drinking water.
Water may also have a role in transmission of poliovirus, Coxsackie,
ECHO, and adenovirus (Clarke and Chang, 1959; Brown and Mc-
Lean, 1967; Chang, 1968).
The role of water in transmission of viral diseases has not been
adequately documented or perhaps considered. The following viral
diseases of domestic animals are examples to show the variation in
viral resistance.
NEWCASTLE
This virus causes an acute systemic infection of fowls, may
infect man, and is highly resistant to detrimental factors of the en-
vironment. In chicken down and dust the virus remains active for
many weeks at ordinary temperatures (Bernkoph, 1964).
HOG CHOLERA
Hog cholera is an acute, highly contagious disease of swine.
caused by a relatively stable virus. One report stated that the virus
at 37° C survived for 7 but not for 15 days (Bruner and Gillespie,
1966). Survival time may be longer and varies with environmental
conditions. Transmission is believed to be primarily by contact with
infected swine, or indirectly by secretions and excretions. The target
date for eradication of hog cholera in the United States is 1975.
FOOT-AND-MOUTH DISEASE
Foot-and-mouth disease is an extremely acute contagious dis-
ease of all cloven-footed animals that rarely infects man. The virus
is resistant to external influence including common disinfectants.
It may persist for more than 1 year in infected premises. The virus is
rather susceptible to heat and pH change and insensitive to cold.
Many methods of transmission occur, with the common method
believed to be ingestion of contaminated feedstuff (Blood and
Henderson, 1968).
OTHER DISEASE AGENTS (VIRAL-LIKE)
The role of water in the transmission of many agents of disease
is unknown. Of recent interest are three disease entities causing
similar chronic neurologic disorders: scrapie in sheep, mink enceph-
alapathy, and Kuru in man. The etiologic agents are extremely re-
sistant and have long incubation periods (McDaniel, 1969). The
agent of scrapie in sheep resists exposure to 75° C for 1 hour, is ether
resistant, and brain tissue in 10 to 12% formalin is still viable after
4 to 28 months (Merchant and Packer, 1967). The role of water
transmission is unknown.
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CHAPTER 19 / DISEASE TRANSMISSION / 277
Fungal Diseases
DEEP SYSTEMIC MYCOSES
The agents of systemic mycotic diseases of importance are acti-
nomycosis, nocardiosis, aspergillosis, phycomycosis, candidiasis, his-
toplasmosis, North American blastomycosis, coccidioidomycosis, cryp-
tococcosis, and sporotrichosis. With the exception of candidiasis the
others are found free living in nature and are not considered to be
zoonotic. These diseases are known as occupational fungi. The
fungi are cultured with ease from soil containing chicken manure,
starling roost, and pigeon feces (Harrell, 1964). Animals and man
are susceptible to these fungi found in the environment. The spores
are airborne-transmitted. Infected animals are not considered res-
ervoirs for the transmission of disease to man (Menges, 1963;
Maddy, 1967).
HISTOPLASMOSiS
Histoplasma infection of man and animals is widespread in
midwestern United States. It is reported sporadic in animals (Blood
and Henderson, 1968). Evidence is lacking on the role of water in
transmission of fungal disease. Gordon et al. (1952) first reported
the isolation of the spore of H. capsulatum from river water.
Experimentally the fungus will remain viable as long as 621
days in water (Metzler et al., 1956). The fungus will grow in ordi-
nary river water. Ordinary water purification processes uniformly
removed spores from the w7ater. It was found that the spores are more
resistant to chlorine than polio virus or enteric bacteria. According
to Furcolow (1965), present evidence of transmission by the water
supply is not considered important. Since spores can easily be
washed into streams, spore content in water storage should be
considered in endemic areas.
SUPERFICIAL MYCOSES-RINGWORM
Certain ringworms are transmitted from animal to man
(Bridges, 1963). The ringworms are considered as major zoonoses.
Direct transmission is the method of common spread. The fungal
spores remain viable for years in a dry environment (Blood and Hen-
derson, 1968). The role of water in the transmission of the spores
has not been determined.
Parasitic Diseases
The diseases associated with helminths and other parasites is
an old science. Helminths were considered important until the dis-
covery of the microscope. Then the era of bacteriology rapidly de-
veloped and pushed the macroscopic forms of parasites into the
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278 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
background. Approximately 60 years ago, with the development of
tropical medicine, worms again become prominent as causative
agents of disease (Cameron, 1962).
Protozoan and helminth diseases are widespread in animals
associated with agriculture. Helminths include the trematodes or
flukes, cestodes or tapeworms, and nematodes or roundworms.
Trematodes or flukes are rare in North America except for
"swimmers itch" in northern lakes. In the United States cestode
diseases are not public health problems of magnitude. The nema-
todes cause many diseases in man and animals, including fish
(Steele, 1968).
In general, larvae and eggs of parasites are relatively resistant
to the external environment. It has been reported (Blood and Hen-
derson, 1968) that during comparatively dry seasons and short
pasture, dung pats can act as reservoirs for larvae for up to 5 months
in the summer and 7 to 8 months in the winter. Under warm and
wet conditions, helminth parasites survive in large numbers for as
long as 6 to 8 weeks, appear relatively resistant to cold, and may
survive through the winter.
Ascarids and the larvae of hookworm may be contracted from
water or soil (Faust et al., 1968). The life cycle of the fluke evolves
in a mollusk, usually a snail. The fluke of "swimmers itch" develops
in a snail. From a single egg, thousands of cercariae emerge in
water and attack any warm-blooded animal, including man. Tape-
worm eggs pass through in feces and all require an intermediate host
to complete the cycle.
BALANTIDIASIS
Balantidiasis is a protozoan disease of cosmopolitan distribu-
tion, usually observed in warm climates. It is a parasite of the in-
testine and most commonly found in swine, monkeys, and man
(Faust, 1963; Van Der Hoeden, 1964). Human infection results fr^m
ingesting contaminated food and water. According to Hoare (1962),
over 90% of the people are infected in some countries.
TOXOPLASMOSIS
Toxoplasmosis is an intracellular protozoan infecting animals
and man. The disease has a wide host range. The mode of trans-
mission is not known (Jacobs, 1964). According to Jacobs (1956),
despite the sea of toxoplasma infection around us the mode of trans-
mission is still in doubt.
ASCARIASIS
Up to 200,000 eggs per day are produced by one female ascarid
(Faust et al., 1968). The eggs are very resistant to cold and survive
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CHAPTER 19 / DISEASE TRANSMISSION / 279
most readily in moist surroundings. Survival up to 5 years has been
recorded (Blood and Henderson, 1968).
STRONGYLOIDES
Strongyloides is a dermatitis developed in trappers, hunters, and
oil workers from swampy areas of southern Louisiana. Infectious
larvae of the Strongyloides species infecting swamp-inhabiting mam-
mals were associated with the disease (Burks and Jung, 1960).
TAENIASIS
Beef infected with cysticercosis, the beef tapeworm, causes
taeniasis in man. The tapeworm is spread to cattle by human
defecation in feed pens and cattle pasture or through distribution of
human sewage and septic tank effluent to pastures. Researchers in
Great Britain concluded that tapeworm eggs can survive most urban
and rural human sewage treatment processes and then pass on in
final effluent or air-dried sludge. This material, if used on pastures
or if it finds its ways to streams, can infect livestock (Silverman and
Griffiths, 1955). In fiscal 1968 in the United States, 12,723 beef
carcasses were reported infected on slaughter (USDA, 1968a).
Prevalence in man is unknown.
SUMMARY AND CONCLUSIONS
There is a growing public concern for the environment and the
need for a reevaluation of water's role as a vehicle in transmission
of animal diseases associated with agriculture. Documented cases
of infectious diseases of animal origin in man and animals have
been associated with water transmission. Following a literature re-
view, it is apparent that adequate consideration of water transmission
has not been made. In many case reports reviewed, no epidemiologic
studies were made to determine the source of infection. In this
chapter an effort is made to indicate the potential epidemiologic
significance based on the variability of the resistant characteristics of
various kinds of pathogenic organisms and their potential for water
transmission.
Much of the past documentation of water transmission has
been associated with bacterial agents. The role of animal viruses and
other agents is practically unknown, and with available methods, the
significance in disease transmission via water cannot be measured.
Pathogenic organisms of animals are found in surface waters, but
for a multiple of factors, disease only occasionally occurs in man
or animals. Factors involved may be the dilution of water, with a
low density of organisms found; the chain of events necessary to
produce the infectious disease process does not develop; or man and
animals are not exposed. If the disease does develop, it is not always
diagnosed or reported.
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280 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
Although in recent years chronic diseases of man have been
of major consideration, the potential of zoonotic diseases through
occupational and recreational exposure may be increasingly signifi-
cant in the future. Water is only one of the methods of disease trans-
mission, but water is essential for life—all animals and man have ex-
posure to water.
In the United States the predicted concentration of populations
of food-producing animals may better facilitate the control and
eradication of animal disease by preventive medicine practices rather
than treatment. Developing problems, such as animal waste dis-
posal and the subsequent environmental effect, increase with live-
stock concentration. Future population growth and new develop-
ments will change occupational and recreational methods, and these
factors will upset the ecologic systems in nature that exist today.
One cannot predict what will happen in the future due to these
ecologic changes.
Ecologic studies of disease in the environment of nature are
filled with the variabilities of the agent-host-environment complex
and are difficult to define. This research needs new approaches.
The future effect of changing agricultural practices, growth and
concentration of animal and human populations, and man's increas-
ing exposure to water will effect a challenge to all scientific disci-
plines to assess the interrelated disease associations.
REFERENCES
Abinanti, F. R. 1964. Respiratory viruses of animals. In Occupa-
tional diseases acquired from animals, ed. H. J. Magnuson, pp.
53-71. Ann Arbor: Univ. of Mich. School of Public Health.
Anderson, G. W., Arnstein, M. G., and Lester, M. R. 1962. Com-
municable disease control. 4th ed. New York: Macmillan.
Andre, D. A., Weiser, H. H., and Malaney, G. W. 1967. Survival of
bacterial enteric pathogens in farm pond water. /. Am. Water
Works Assoc. 59:503-8.
Babudieri, B. 1959. Q fever a zoonosis. In Advances in veterinary
science, ed. C. A. Brandly and E. L. Jungherr, pp. 81—182.
New York and London: Academic Press.
Bernkopf, H. 1964. Newcastle disease. In Zoonoses, ed. J. Van Der
Hoeden, pp. 396—400. Amsterdam, London, New York: Elsevier.
Blood, D. C., and Henderson, J. A. 1968. Veterinary medicine. 3rd
ed. Baltimore: Williams and Wilkins.
Bosworth, T. J. 1934. Persistence of Brucella on the aborted foetus
and its membranes. Univ. of Cambridge, Inst. of An. Pathol.,
Rept. of the Director 4:65-71.
Brackman, P. S. 1964. Anthrax. In Occupational diseases acquired
from animals, ed. H. J. Magnuson, pp. 216-27. Ann Arbor:
Univ. of Mich. School of Public Health.
Bridges; D. H. 1963. Fungous diseases. In Diseases transmitted
from animals to man, ed. T. G. Hull, 5th ed., pp. 453—507.
Springfield, 111.: Charles C Thomas.
Brown, J. R., and McLean, D. M. 1967. Water-borne diseases, an
historical review. Medical Services J. Can., pp. 1011-26.
Bruner, D. W., and Gillespie, J. H., eds. 1966. Hagan's infectious
-------
CHAPTER 19 / DISEASE TRANSMISSION / 281
diseases of domestic animals. 5th ed. Ithaca: Cornell Univ.
Press.
Bulloch, W. 1938. The history of bacteriology. London, New York,
Toronto: Oxford Univ. Press.
Burks, J. W., and Jung, R. C. 1960. A new type of water dermatitis
in Louisiana. Southern Med. J. 53:716-19.
Cameron, T. W. M. 1962. Helminths of animals transmissible to
man. In Progress of medical science, pathology and bacteriology,
ed. R. W. Reed and G. C. McMillan. Am. ]. of Med. Sci. 130/
354, 157/381.
Chadwick, J., and Mann, W. N., collaborators. 1950. The medical
ivork of Hippocrates. A new translation from the original Greek
made especially for English readers. Oxford: Blackwell Scien-
tific Publ.
Chang, S. L. 1968. Waterborne viral infections and their preven-
tion. Bull. World Health Organ. 38:401-14.
Chang, S. L., Buckingham, M., and Taylor, M. P. 1948. Studies on
L. icterohaemorrhagiae. IV. Survival in water and sewage. De-
struction in water by halogen compounds, synthetic detergents
and heat. /. Infect. Diseases 82:256-66.
Christiansen, M. J. 1943. Graemarks infektion og kvaegtuberkulose.
Maadskrift Dyrlaeger 54:241-305.
Clarke, N. A., and Chang, S. L. 1959. Enteric viruses in water. /.
Am. Water Works Assoc. 51:1299-1317.
Decker, W. M., and Steele, J. H. 1966. Health aspects and vector
control associated with animal wastes. Proc. Nat. Symp. Ani-
mal Waste Management, pp. 18—20. Mich. State Univ., East
Lansing.
Diesch, S. L., and McCulloch, W. F. 1966. Isolation of pathogenic
leptospires from waters used for recreation. Public Health Rept.
81:299-304.
Diesch, S. L., McCulloch, W. F., Braun, J. L., and Crawford, R. P.,
Jr. 1969. Environmental studies on the survival of leptospirosis
in a farm creek following a human leptospirosis outbreak in
Iowa. Proc. Ann. Conf. Bull. Wildlife Disease Assoc. 5:166—73.
Edwards, P. R., and Galton, M. M. 1967. Salmonellosis. Advan.
Vet. Sci. 1:63.
Errington, P. L. 1963. The phenomenon of predation. Am. Scientist
51:180-92.
Faust, E. C. 1963. Infections produced by animal parasites. In Dz's-
eases transmitted from animals to man, ed. T. G. Hull, 5th ed.,
pp. 433-52. Springfield, 111.: Charles C. Thomas.
Faust, E. C., Beaver, P. C., and Jung, R. C. 1968. Animal agents
and vectors of human disease, 3rd ed. Philadelphia: Lea and
Febiger.
Feldman, W. H. 1963. Tuberculosis. In Diseases transmitted from
animals to man, ed. T. G. Hull, 5th ed, Springfield, 111.: Charles
C Thomas.
Fox, J. P. 1964. Rickettsial diseases other than Q fever as occupa-
tional hazards. In Occupational diseases acquired from animals,
ed. H. J. Magnuson, pp. 98-109. Ann Arbor: Univ. of Mich.
School of Public Health.
Furcolow, M. L. 1965. Environmental aspects of histoplasmosis.
Arch. Environ. Health 10:14-10.
Geldreich, E. E. 1965. Origins of microbial pollutions in streams.
In Transmission of viruses by the water route, ed. G. Berg, pp.
-------
282 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
355—61. New York, London, Sidney: Interscience Publishers.
Gibson, E. A. 1967. Disposal of farm effluent. Agriculture 74(4):
183-88.
Gillespie, R. W. H., and Ryno, J. 1963. Epidemiology of leptospiro-
sis. Am. ]. Public Health 53:950-55.
Classman, H. N. 1958. World incidence of anthrax in man. Public
Health Kept. 73:22-24.
Gordon, M. A., Ajello, L., Georg, L. K., and Zeidberg, L. D. 1952.
Micro sporum gypseum and Histoplasma capsulatum spores in
soil and water. Science 116:208.
Gratzek, J. B. 1967. General aspects of viral diseases. In Veterinary
bacteriology and virology, ed. I. A. Merchant and R. A. Packer,
5th ed., pp. 582—88. Ames: Iowa State Univ. Press.
Green, M. 1965. Major groups of animal viruses. In Viral and rick-
ettsial infections of man, ed. F. L. Horsfall and I. Tamm, 4th
ed., pp. 11-18. Philadelphia, Toronto: J. B. Lippincott.
Harrell, E. R. 1964. The known and the unknown of the occupa-
tional mycoses. In Occupational diseases acquired from ani-
mals, ed. H. J. Magnuson, pp. 176-78. Ann Arbor: Univ. of
Mich. School of Public Health.
Harris, H. J. 1950. Brucellosis (undulant fever). 2nd ed. New York:
Paul B. Hoeber.
Hibbs, C. M., and Foltz, V. D. 1964. Bovine salmonellosis associated
with contaminated creek water and human infection. Vet. Med.
59:1153-55.
Hoare, C. A. 1962. Reservoir hosts and natural foci of human proto-
zoal infections. Acta Trop. 19:281-317.
Ignatovich, V. F. 1959. The course of inactivation of Rickettsia
burneti in fluid media. ]. Microbiol. Epidemiol. Immunol.
30:134-41.
Jacobs, L. 1956. Propagation, morphology, and biology of toxoplas-
mosis. Ann. N.Y. Acad. Sci. 64:154-79.
. 1964. Actual and potential importance of protozoal and hel-
minth zoonoses as occupational hazards. In Occupational dis-
eases acquired from animals, ed. H. J. Magnuson, pp. 344—43.
Ann Arbor: Univ. of Mich. School of Public Health.
Jellison, W. L., Kohls, G. M., Butler, W. J., and Weaver, J. A. 1942.
Epizootic tularemia in the beaver, Castor canadensis, and the
contamination of stream water with Pasteurella tularensis. Am.
J. Hyg. 36:168-82.
Jellison, W. L., Epler, D. C., Kuhns, E., and Kohls, G. L. 1950. Tu-
laremia in man from a domestic rural water supply. Public
Health Rept., pp. 1219-26.
Jones, T. L. 1963. Diseases of cattle. 2nd ed. Santa Barbara, Calif.:
Am. Vet. Publ.
Joyce, G., and Weiser, H. H. 1965. Survival of enteroviruses and
bacteriophage in farm pond waters. /. Am. Water Works Assoc.
pp. 491-501.
Kalter, S. S. 1964. Enteroviruses in animals other than man. In
Occupational diseases acquired from animals, ed. H. J. Magnu-
son, pp. 126-59. Ann Arbor: Univ. of Mich. School of Public
Health.
Karlson, A. G. 1967a. The genus Erysipelothrix. In Veterinary bac-
teriology and virology, ed. I. A. Merchant and R. A. Packer, 7th
ed., pp. 466-74. Ames.- Iowa State Univ. Press.
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CHAPTER 19 / DISEASE TRANSMISSION / 283
•. 1967b. The genus Mycobacterium. In Veterinary bacteriology
and virology, ed. I. A. Merchant and R. A. Packer, 7th ed., pp.
441-65. Ames: Iowa State Univ. Press.
Kraus, P., and Weber, G. 1958. Untersuchungen liber die Haltbor-
heit von Krankheitserregern intrink-und oberflacherwasser.
Zentr. Bakteriol. Parasitenk. Abt. I. Orig. 171:509-23.
McCroan, J. E., McKinley, T. W., Brin, A., and Ramsey, C. H. 1963.
Five salmonellosis outbreaks related to poultry products. Pub-
lic Health Rept. 78:1073-80.
McDaniel, H. A. 1969. Comparative chronic neurological disorders.
In Midwest interprofessional seminar on diseases common to
animals and man. (Abstr.) Ames.- Iowa State Univ.
Maddock, E. C. G. 1933. Studies on the survival time of the bovine
tubercle bacillus in soil, soil and dung, in dung and on grass,
with experiments on the preliminary treatment of infected or-
ganic matter and the cultivation of the organisms. J. Hyg.
33:103-17.
Maddy, K. T. 1967. Epidemiology and ecology of deep mycoses of
man and animals. Arch. Dermatol. 96:409—17.
Menges, R. W. 1963. A review and recent findings on histoplas-
mosis in animals. Vet. Med. 58:331-38.
Merchant, I. A., and Packer, R. A. 1961. Veterinary bacteriology
and virology. 6th ed. Ames: Iowa State Univ. Press.
. 1967. Veterinary bacteriology and virology. 7th ed. Ames:
Iowa State Univ. Press.
Metzler, D. F., Ritter, C., and Culp, R. L. 1956. Combined effect of
water purification processes on removal of Histoplasma capsu-
latum from water. Am. ]. Public Health 46:1571-75.
Middlebrook, G. 1965. The mycobacteria. In Bacterial and mycotic
infections of man, ed. R. J. Dubos and J. G. Hirsch, 4th ed.,
pp. 490-521. Philadelphia, Montreal: J. B. Lippincott.
Morgan, H. R. 1965. The enteric bacteria. In Bacterial and mycotic
infections of man, ed. R. J. Dubos and J. G. Hirsch, 4th ed., pp.
610-48. Philadelphia, Montreal: J. B. Lippincott.
Morse, E. V. 1963. Swine erysipelas. In Diseases transmitted from
animals to man, ed. T. G. Hull, 5th ed., pp. 186-209. Spring-
field, 111.: Charles C Thomas.
Mosley, J. W. 1963. Epidemiologic aspects of viral agents in rela-
tion to water-borne disease. Public Health Rept. 78:328-30.
National Communicable Disease Center. 1965a. Leptospirosis. Zo-
onosis Surveillance Rept. 7.
. 1965b. Morbidity and mortality iveekly rept., vol. 14, no. 22,
June 5.
Ogarkov, V. I. 1962. Infectiousness of various objects and materials
contaminated with Brucella. J. Microbiol. (Moscow) 4:88.
Parker, R. P., Steinhaus, E. A., Kohls, G. M., and Jellison, W. L. 1951.
Contamination of natural waters and mud with Pasteurella tu-
larensis and tularemia in beavers and muskrats in the north-
western United States. U.S. Nat. Inst. of Health Bull. 193. Pub-
lic Health Serv. 1-61.
Prier, J. E., and Riley, R. 1965. Significance of water in natural
virus transmission. In Transmission of viruses by the ivater
route, ed. G. Berg, pp. 287-300. New York, London, Sidney:
Interscience Publishers.
Quan, S. F., McManus, A. G., and von Fintel, H. 1956. Infectivity
-------
284 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
of tularemia applied to intact skin and ingested in drinking
water. Science 123:942-43.
Reed, R. W. 1965 Listeria and Erysipelothrix. In Bacterial and my-
cotic infections of man, ed. R. J. Dubos and J. G. Hirsch, 4th ed.,
pp. 757-62. Philadelphia, Montreal: J. B. Lippincott.
Rowsell, H. C. 1958. The effect of stomach contents and the soil on
the viability of Erysipelothrix rhusiopathiae. }. Am. Vet. Med.
Assoc. 132:357-61.
Ryu, E., and Liu, C-K. 1966. The viability of leptospires in the sum-
mer paddy water. Japan. J. Microbiol. 10:51—57.
Schaal, E. 1963. Enzootic salmonellosis in a herd of cattle caused
by infected brook water. Deut. Tieraerztl. Wochschr. 70:267-
68.
Shaughnessy, H. J. 1963. Tularemia. In Diseases transmitted from
animals to man, ed. T. G. Hull, 5th ed., pp. 588-604. Spring-
field, 111..- Charles C Thomas.
Silverman, P. H., and Griffiths, R. B. 1955. A review of methods of
sewage disposal in Great Britain with special reference to the
epizootiology of Cysticercus bovis. Ann. Trap. Med. Parasitol.
49:436-50.
Sinha, S. K., Fleming, L. W., and Scholes, S. 1960. Current con-
siderations in public health of the role of animals in relation
to human viral diseases. /. Am. Vet. Med. Assoc. 136:481-85.
Steele, J. H. 1968. Occupational health in agriculture. Arch. En-
viron. Health 17:267-85.
Stein, C. D. 1942. Anthrax. In Keeping livestock healthy. USDA
Yearbook of Agriculture, pp. 250-62.
Sterne, M., and Van Heyningen, W. E. 1965. The clostridia. In Bac-
terial and mycotic infections of man, ed. R. J. Dubos and J. G.
Hirsch, 4th ed., pp. 454-72. Philadelphia, Montreal: J. B. Lip-
pincott.
Stoenner, H. G. 1964. Occupational hazards of Q fever. In Occu-
pational diseases acquired from animals, ed. H. J. Magnuson,
pp. 36-52. Ann Arbor: Univ. of Mich. School of Public Health.
Tigertt, W. D.. Benenson, A. S., and Gochenour, W. S. 1961. Air-
borne Q fever. Bacterial. Rev. 25:285-93.
U.S. Dept. of Agriculture. 1965. Losses in agriculture. ARS Agri-
cultural Handbook 291.
. 1968a. Livestock Slaughter Inspection Division Kept.
. 1968b. Statistical report.
. 1969. Cattle on feed. Statistical Report, 1 Jan.
U.S. Outdoor Recreation Resources Review Commission. 1962. Out-
door recreation for America, a report to the President and to the
Congress. Wash., B.C.
Van Der Hoeden, J. 1964. Brucellosis. In Zoonoses, ed. J. Van Der
Hoeden, pp. 95-132. Amsterdam, London, New York: Elsevier.
Welsh, H. H., Lennette, E. H., Abinanti, F. R., Winn, J. F., and Kap-
lan, W. 1959. Q fever studies. XXI. The recovery of Coxiella
burnetii from soil and surface waters of premises harboring in-
fected sheep. Am. ]. Hyg. 70:14-20.
Wilson, J. B., and Russell. K. E. 1964. Isolation of Bacillus an-
thracis from soil stored for 60 years. /. Bacteriol. 87:237.
World Health Organization. 1962. Occupational health problems
in agriculture. Fourth report of the joint ILO/WHO committee
on occupational health. Tech. Rept. Ser. 246.
-------
CHAPTER 19 / DISEASE TRANSMISSION / 285
-. 1967a. Current problems in leptospirosis research. Report of
a WHO expert group. Tech. Kept. Ser. 380.
1967b. Joint FAO/WHO expert committee on zoonoses. Third
Kept. Tech. Kept .Ser. 378.
Young, L. S., Bicknell, D. S., Archer, B. G., Clinton, J. M.. Leavens,
L. J., Feeley, J. C., and Brachman, P. S. 1969. Tularemia epi-
demic: Vermont, 1968. Forty-seven cases linked to contact
with muskrats. Nezu Engl. J. Med. 280:1253-60.
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CHAPTER TWENTY.
ANIMAL WASTE MANAGEMENT
TO MINIMIZE POLLUTION
J. A. MOORE
I HE practice of managing animal waste to control pollution
began when animals were confined. Today livestock operations tend
to be more confined and continue to increase in size. This requires
a higher degree of waste management. Social attitudes are changing
the definition of pollution and the degree of acceptability, thus requir-
ing more waste management. Taste and color, odors, dust, organic
and inorganic matter, plant nutrients, insects, and pathogenic bac-
teria are all pollutional factors which can result from the mismanage-
ment of animal waste.
Management is defined by Webster as "the act or art of planning,
organizing, coordinating, directing, controlling, and supervising any
project or activity with the responsibility for results." Looking par-
ticularly at animal waste management this act may be broken down
into four separate functions: collection, storage, treatment, and uti-
lization or disposal. Not all systems contain all of the above processes
and for any one system the order may be changed. This chapter will
look at these four steps as they affect water pollution.
While all the steps will be discussed separately there is a very
definite relationship among the functions. In most livestock opera-
tions, the ultimate utilization or disposal practice will strongly dictate
the nature of the other processes employed in the waste management
system.
Manure varies in composition and characteristics because of dif-
ferences in specie, breed, age of the animal, and the ration. Number
of animals, geographic locations, climatic conditions, proximity to
populated areas, and land availability should be considered in select-
ing a workable and satisfactory management system.
COLLECTION
The collection process can be divided into two types: wet or dry.
The dry system can be defined as that which does not add any dilu-
J. A. MOORE is Instructor, Department of Agricultural Engineering,
University of Minnesota.
286
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CHAPTER 20 / ANIMAl WASTE MANAGEMENT / 287
tion or conveying water to the waste. Dry systems minimize the vol-
ume of waste material that must be further processed, while wet
systems utilize the efficiency obtained with liquid-carried transporta-
tion. The low cost of water and the efficiency of pumping systems
can make liquid collection very attractive if utilization or disposal of
this additional volume of wastewater is available.
In dry systems the manure is usually deposited on the floor, pen,
or under the cage and collected and removed to the next process at
some given frequency. In the open feedlot operation, the manure may
be stored in a lot for several months before being collected and re-
moved. Many dairy operations use mechanical equipment to remove
waste from the building on a daily basis. Gutter cleaners, shuttle
stroke and endless belt conveyors, powered carts, and small and large
tractors are examples of some of the mechanical equipment which
has been developed to reduce the labor required for collection.
Flushing gutters have been used successfully in poultry, swine,
and dairy operations which use liquid collection systems. If disposal
is no great problem, clean water can be used for flushing; in other
operations some treatment can be employed to permit the recycling
of flushing water. In operations using flushing systems the installa-
tion of impervious channels or conduits is essential. If any of this
wastewater is allowed to escape, either by design or otherwise, unde-
sirable conditions result.
Manure solids which are allowed to settle out on the bottom or
sides of waterways will continually be rewet and stink, attract flies
and rodents, and be very unsightly.
Since water is being used as a carrier for the manure, it is
important that this liquid does not seep into the soil or through cracks
in the conveying system. If the above occurs, the solid will be left
high and dry and can create the nuisance conditions mentioned
above. A loss of water will result in a buildup of solids on the surface
and "polluted" water moving into the soil and eventually the ground-
water.
Some operations use sloping bottom ponds to collect and hold
the wraste slurry for bimonthly flushing. If water is allowed to seep
out, the collection process has failed and the above-mentioned condi-
tions result.
The development of slatted floor structures has expanded the
use of storage tanks under the housing area to collect and store ma-
nure. The use of fully slatted floors can eliminate the need for labor,
either hand or mechanical, in the collection process.
In almost all construction the under-the-floor storage tank is de-
signed to function as part of the structural members of the building
foundation. These components are almost always concrete and serve
as a water-tight storage unit, thus eliminating any water pollution.
STORAGE
Storage may be the first process in the waste management sys-
tem. Many beef feedlots and poultry operations allow manure to
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288 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
build up and employ only annual or semiannual clean-out schedules.
In some poultry operations shallow liquid pits are constructed
under the cages and manure is collected and stored in these for a
bimonthly flushing. This storage process in liquids for a short period
of time minimizes odor production and eliminates flies. When these
shallow pits become full, the slurry may be flushed to a larger tank
for some additional storage or immediate removal and disposal.
These units are usually concrete lined, which prevents any deep
percolation losses.
Storage of the manure collected in tanks under slat floors may
extend over long periods of time and accomplish several purposes.
Storage tanks eliminate the need for labor in the collection process.
Feces deposited in the slats by the animals are worked through so the
livestock operator need exert no energy in getting this waste into the
tank. These tanks can contain the waste until the land, or some other
treatment or disposal system, is in condition to accept the manure.
The effectiveness of adding this organic matter and plant nutrients
to the soil is reduced in the winter when heavy snowfall and freezing
temperatures are encountered.
If animal waste is collected and spread in the winter, the waste
may actually be stored above the land in a frozen condition until
spring. Because of the cold weather experienced in northern climates,
very Little processing in the way of anaerobic or aerobic microbial
activity takes place during the winter. Depending upon the amount
of precipitation, slope of the ground, and overland flow from higher
elevations, this site may continue to serve as storage until the animal
waste is completely stabilized, leached, or mechanically incorporated
into the soil.
Storage of animal manures is also required after processing in
some cases. In operations in which effort and energy are expended
to reduce the moisture content, storage can be employed to maintain
the product in its postprocess condition. Processes such as drying,
composting, and dehydration reduce the moisture content which gen-
erally results in lower nuisance levels. This material can then be
further processed into feed or fertilizer or applied on the land as the
demand and time allow. Storage requires that external moisture
sources, such as rainfall and snow, be kept from the processed ma-
nure. If this objective is met, then any water pollution threat is
eliminated.
TREATMENT
Many may consider processing as a step or method involved in
preparing a marketable product, and treatment as any step or method
involved in stabilizing or reducing waste products. Here, treatment
and processing will be used to mean any method involved in an
attempt to make the product marketable or reduce or stabilize the
material.
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CHAPTER 20 / ANIMAL WASTE MANAGEMENT / 289
Dry Systems
By far the most effective way to minimize the water pollution is
to remove moisture from the manure and then provide safeguards to
eliminate or minimize its subsequent contact with water. The major
treatment systems which remove moisture from the waste are drying,
dehydration (which differ only in the amount of moisture removed),
incineration, and composting.
Natural drying is extensively used as a treatment process in the
arid regions of the Southwest. This method is employed because of
the low humidity and high temperature which are encountered in
this area. The very conditions which allow this system to be used
also reduce water pollution potential. Dust can be a major nuisance
in these areas.
When wet periods in winter or high intensity summer thunder-
showers occur, dikes or catchments can be used to collect and con-
tain the runoff until evaporation can remove the water. By removing
the solids from catchments or sedimentation chambers and frequently
scraping the pens, runoff water quality can be improved. In many
areas in the Southwest continuously running surface waters are not
common, and generally the water table is very deep. These two
factors greatly reduce the water pollution hazard.
In systems employing dehydration or incineration, water contact
and subsequent pollution are avoided. Most operations process the
waste directly from the defecation site. Since dehydration is relatively
expensive, the resulting product is usually stored or further processed
without the opportunity to contact and pollute water.
In the incineration process the remaining ashes possess little
threat to water pollution when compared to the original product. In-
cineration can be accomplished without polluting the air, but this is
an expensive operation and is not widely used as a disposal system
for animal manures.
Composting is a process of promoting aerobic degradation of or-
ganic wastes in a relatively dry condition. This can be accomplished
in a pile or windrow, much the same as you might make leaf or
vegetable waste compost in your backyard, only on a larger scale.
This process is usually mechanized and can take place in a large re-
volving drum which may be heated and ventilated. When this
method is employed on a large scale it is not a great contributor to
water pollution.
Wet Systems
Water pollution hazards are increased in liquid waste manage-
ment systems. The relatively inexpensive price of water allows oper-
ators to use liquid systems for the advantage obtained in the trans-
portation of this material. Liquid systems have many things in
common with municipal sewage treatment plants and all of the
engineering and biological principles apply.
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290 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
For economic reasons the livestock operator is unable to handle
and treat animal waste in the same manner as domestic sewage.
Actually sewage is about 99% clean water and 1% waste. To dilute
animal waste to the same consistency and employ similar treatment
systems would be economically prohibitive. It has been reported that
homeowners pay about 0.9 cents per pound for municipal refuse col-
lection, treatment, and disposal, while a similar operation would cost
the dairyman $200 per cow, per year (Hart, 1964a).
Since many treatment operations were developed by Civil Sani-
tary Engineers, we will use their terms to describe three of the basic
treatment processes which do apply to animal manure.
PRIMARY TREATMENT
The first treatment process is called primary treatment. In this
process floating, suspended, and settleable solids of untreated waste
are reduced by sedimentation and screening.
Screening. Screening of animal waste as a treatment process
has not been used in any commercial livestock operations. Research-
ers have evaluated it and reported that dairy cattle waste strained
through a No. 4 (4.76-mm opening) sieve removes 50% of the solids
by weight and 36% of the BOD5 an a 2% solids slurry (Dale and Day,
1967). A similar study found that only 12% of the total solids of the
dairy waste and none of the solids of chicken waste were held above
a No. 8 sieve (2.38-mm opening) (Sobel, 1966). While they do not
agree, both of these studies indicate that screening can serve to take
out some of the undigested corn kernels, hay stems, and silage which
are common to most feeds. These materials are relatively inert and
not amenable to biologic treatment.
Sedimentation. Sedimentation has been and can be a very ef-
fective treatment method of animal waste. Gravity is the principal
force causing matter to settle in water. While the principles of this
phenomenon are well defined and understood, no formula, theoretical
or empirical, has been devised that is applicable to practical sedi-
mentation-basin design because of the widely varying conditions oc-
curring during operation. Some of the conditions which affect the
efficiency of the operation are size of particles (the greater the size.
the more rapid is the rate of settling), specific gravity of the particles.
concentration of the suspended matter, period of retention, and the
velocity of flow through the basin.
Sedimentation can serve as a treatment scheme before a second-
ary system or be designed to function at the same time. Beef cattle
feedlots serve as a good example to employ either or both of these
systems. Natural precipitation that falls on or is allowed to run
through open feedlots becomes polluted and may have a suspended
solids concentration as high as 10,300 mg/1 (Miner et al., 1966).
Several studies (Miner et al., 1966; Loehr, 1969; Norton and
Hansen, 1969) have reported the relationships and effects of the in-
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CHAPTER 20 / ANIMAL WASTE MANAGEMENT / 291
tensity, duration, slope, etc., on the quality and quantity of runoff
water from cattle feedlots.
Laboratory studies have been conducted on animal manure to
determine the settleable matter. The test is denned in standard meth-
ods, but basically measures the solid material that will settle from a
1-liter sample in 60 minutes.
The suspended and dissolved solids were found to be a function
of dilution, ration, and detention time, with dairy manure settling
from 20% to 95% in 1 hour as the dilution ratio changed from 2:1
to 10:1 (Sobel, 1966). Similar settling curves have been plotted for
chicken manure with dilution ration and settling time as the varia-
bles. When looking at this method as a treatment system it is helpful
to realize that it is the organic nonsettleable suspended solids and the
organic dissolved solids which leave the settling chamber and exert
the BOD in the effluent. In beef cattle waste this amounts to 39% of
the manure added to the system (Ward and Jex, 1969).
SECONDARY TREATMENT
There are two different biological processes which constitute sec-
ondary treatment systems: aerobic and anaerobic systems. However,
it is customary to recognize three major subtypes of energy-yielding
metabolism: fermentation, aerobic respiration, and anaerobic respira-
tion (Stanier et al., 1965). These three processes are distinguished
from one another by differences of the ultimate electron acceptor.
Anaerobic Systems. Anaerobic respiration can be defined as
those biological oxidations which use an inorganic compound other
than oxygen as the final electron acceptor. Nitrates, sulfates, and
carbonates are commonly used as the electron acceptor by anaerobic
bacteria.
One of the main advantages this type of system has to offer in
the treatment of animal waste is the high degree of stabilization that
is possible. Unlike the aerobic oxidation, the anaerobic conversion
to methane gas yields little energy to the microorganisms. This low
energy conversion does not support the growth of a large number of
new cells and the resulting end products are primarily carbon dioxide
and methane gas.
Since cell growth is slow there is a low production of waste bi-
ological sludge. Nutrient requirements are low for this type of system
and since oxygen is not required, the power requirements for opera-
tion are reduced. In many municipal operations methane gas is col-
lected and can be used as a heat source for the waste digestor, heating
buildings, or generating electricity.
It has been shown that as much as 90% of the degradable or-
ganics of a waste can be stabilized in anaerobic treatment while only
about 50% is stabilized in an aerobic system (McCarty, 1964a).
While the system has advantages, the disadvantages begin to weigh
very heavily when treating wastes with BOD concentration of less
than about 10,000 mg/1.
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292 / PART 4 / ANIMAL WASTES AS WATER POUUTANTS
The major disadvantage of the anaerobic system is the high tem-
perature required for optimum operation; temperatures about 90° F
are preferred. While heating the digesters is a common practice for
municipality and some industrial wastes, agriculture has yet to make
widespread use of this technique. Most livestock operators are not
interested in developing the stalls required to run a good anaerobic
digester. This usually involves a knowledge of mixing ratios, pH
control, etc.
Using other than oxygen as the electron acceptor results in the
production of some foul odors. With the present public awareness
and demand for high environmental quality, the anaerobic systems
are definitely handicapped because of the odor production character-
istics. Because of the low energy realized in the process, the treat-
ment is not rapid and requires a longer period of time for start-up
and adjustment to temperature and loading changes.
However, the use of unmanaged anaerobic lagoons to treat ani-
mal waste is widespread in this country. In this sense an anaerobic
lagoon can be defined as a tank, pit, or reservoir over 5 feet deep
which receives animal waste in some dilute concentration. The 5-
foot minimum depth eliminates the transfer and mixing of oxygen
from the surface by thermal current or wind action.
Many authors (Hart, 1963; McCarty, 1964b; Hart and Turner.
1965; Curtis, 1966; Willrich, 1966; Loehr, 1967, 1968; Gramms et al..
1969; Schmid and Lipper, 1969) have studied anaerobic lagoons
in the laboratory and field for all the major farm animals. The load-
ing rates reported for each animal ranged from near zero to 4,000
chickens, 250 hogs, or 45 cattle per 1,000 cubic feet of liquid; the
loading rates most often suggested were about one-half of these maxi-
mum values.
There is no standard measurement by which all of the above
investigators can compare results. Each is likely to have his own
list of objectives and criteria to measure the success of his project
and then to project loading rates. Sludge buildup rate is one opera-
tional parameter which affects the frequency of cleanout. This is a
rather costly operation and in some locations the use of additional
land for a larger or second lagoon will eliminate this cost.
Lagoons can be operated on a batch or continuous basis. Gen-
erally the effluent from an anaerobic lagoon cannot be discharged to a
surface waterway. Sprinkling onto pasture or a waste disposal plot
may provide a final disposal site for excess liquid. Recycle of flushing
or wash water is one method of reducing effluent from the waste
disposal system.
Some locations will allow the construction of a lagoon site with
a designed seepage rate, while other sites may be required to construct
an impervious lagoon.
Temperature is perhaps the variable which has the greatest in-
fluence on the performance of an anaerobic lagoon. Amount of mix-
ing, pH, salinity, detention time, and type of ration fed to the animals
will also affect the operation of the system.
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CHAPTER 20 / ANIMAL WASTE MANAGEMENT / 293
Aerobic Systems. Respiration (aerobic metabolism) is that class
of biological oxidations which utilizes molecular oxygen as the final
electron acceptor.
Oxygen is transferred naturally in turbulent flowing streams and
rivers and in shallow ponds and lagoons. Algae can also be a major
contribution of oxygen to a pond. However, the relationship is not
always favorable as algae produce oxygen in the sunlight and con-
sume it at night. If these natural processes are not sufficient, then
mechanical means can be employed to provide additional oxygen.
With adequate oxygen and the waste as a food source, aerobic
bacteria grow rapidly and degrade soluble organics very effectively.
In this growth some of the waste is converted to cells, which consti-
tutes a biological floe. In final settling this sludge material is re-
moved and some of it becomes a solid water product which creates
the need for another disposal system.
Oxidation Ponds. Sufficient oxygen levels can be maintained in
ponds or lagoons limited to about 4 feet deep if the loading rate is
not too great. Generally aerobic lagoons are designed to treat 20 to
40 pounds of BOD/acre/day, depending upon location. Using the 40-
pound rate this is equivalent to 2,600 chickens, 100 hogs, or 30 cat-
tle/acre/day. These figures were generated by reviewing several of
the articles in the field (Babbit and Baumann, 1958; Forges and Taft,
1964; Clark, 1965; Jeffrey et al., 1965; Loehr, 1968) and summarizing
the reported results.
Wind action, temperature, depth, and amount of sunlight will
all influence the treatment. If the loading is light or the detention
time is long the effluent may be of sufficient quality to allow discharge
to a surface waterway. Several lagoons in series are sometimes em-
ployed to provide treatment that will allow discharge.
Depth to water table, soil type, crop, rainfall, slope of the land,
and water quality will influence final disposal at this effluent. In
areas where evaporation is greater than rainfall, a final liquid dis-
posal system may not be necessary.
In many treatment systems supplemental air has to be provided,
and this can be done with rotors or aerators which strike the surface
of the water and increase oxygen transfer or by employing com-
pressors and bubbling air up through the liquid. While the above
equipment is expensive, the freedom from noxious odors may be
worth the price. Waste digestion and odor control are factors which
must be considered in a livestock production operation today.
Aerated Lagoons. Some manufacturers of floating aerators have
guaranteed that their equipment will supply about 3 pounds of oxy-
gen per horsepower hour at standard conditions (Dale et al., 1969).
An operator can determine the total oxygen demand of his waste load
and select the necessary equipment. In design it is best to supply
twice the oxygen demand to ensure sufficient dissolved oxygen in
the entire system.
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294 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
Oxidation Ditches. While floating aerators (vertical shaft units)
splash, mix, and reaerate the liquid in a lagoon, rotors (horizontal
shaft units) are used to accomplish the same functions in an oxida-
tion ditch. These units are generally constructed under a slatted floor
building. As such they are almost always water tight and prevent
any seepage losses.
Most rotors can transfer 1 to 1.5 pounds of oxygen/hr/foot of
rotor length. This system holds much promise to contain and treat
the waste in an odor-free environment; several investigators (Irgens
and Day, 1966; Dale and Day, 1967; McKinney and Bella, 1967;
Jones et al., 1969; Ludington et al., 1969; Moore et al., 1969) have
studied the loading rates and operation characteristics of this system.
There are over 100 oxidation ditches in use in this country. Most
of these units are in hog operations, with only limited application to
beef wastes. The above researchers suggest that 10 ftVhog and 60
ftVbeef animals are leading rates that can be applied to oxidation
ditches.
These systems can be operated on a batch basis or with a con-
tinuous overflow, which requires an additional treatment system. As
indicated above temperature and loading rate will influence the
pollutional reduction and rate of solids buildup.
Trickling Filter. The trickling filter is an aerobic system that is
widespread in the treatment of domestic wastes. While it has been
demonstrated in a laboratory study that this method can be applied
to dairy waste, the system has economic and management require-
ments which have limited its agricultural application (Bridgham and
Clayton, 1966).
Combination Systems. Investigators (Agnew and Loehr, 1966;
Webster and Clayton, 1966; Loehr, 1969) have explored the advan-
tages of combining an anaerobic and aerobic process to form n com-
plete treatment system. It would appear that some combination of
the two can utilize the advantages of both and provide a good system.
Field trials to date do not allow the projection of sizes and loading
rates required for commercial units.
TERTIARY TREATMENT
Secondary treatment systems may have removed up to 90% of
the original organic matter. In the event additional treatment is re-
quired, this is called tertiary or third-degree treatment. Since most
of the solids have been removed and much of the oxygen-dermnd ma-
terials have been oxidized, this additional treatment may be aimed
at nutrient removal.
Nutrients, primarily nitrogen and phosphorus, can be responsible
for the growth of algae and other unwanted plants. Tertiary treat-
ment is presently being Implemented in a few domestic waste treat-
ment plants.
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CHAPTER 20 / ANIMAL WASTE MANAGEMENT / 795
Like most cities of several years ago, the animal industry is today
thinking about primary and secondary treatment and has not yet
been encouraged to employ tertiary treatment systems. Nutrients are
generated in large quantities in livestock operations, and these do
represent a very real pollution potential. While application of nu-
trient removal systems for animal wastes is some distance in the
future, proper management of this material can maximize the benefit
of utilization and minimize the pollution from disposal.
UTILIZATION AND DISPOSAL
Almost all of the utilization and disposal of animal manures will
be through land application. Some attempts have been made to re-
cover portions of the waste product for the drug industry, but these
have generally met with limited success and less application. Incin-
eration does a good job of disposing of manure and almost eliminating
all water pollution potential, but cost has kept this from widespread
use.
It is not within the scope of this chapter to review or report any
or all of the volumes of work that have been published by agrono-
mists, soil scientists, engineers, and others on the effect of animal ma-
nure on soil and crop responses. Many report that animal manure
cannot compete with manufactured fertilizers and this is very true,
but manure will continue to be produced and we must look to least-
cost disposal systems which still maintain our environment quality
if we wish to continue producing livestock.
Work done at Rutgers University shows that engineering systems
can be developed to apply liquid manure to the soil (Reed, 1966). This
plow-furrow-cover system employs equipment which opens a plow
furrow, applies up to 225 tons of liquid manure per acre and then
covers up this material, which maximizes soil contact and stabiliza-
tion and minimizes environmental pollution (Reed, 1969).
Chopper pumps are now available that can move any material
that will flow to the pump (Hart et al., 1966). Large rubber nozzles
on sprinkler heads will allow irrigation systems to convey and spread
liquid manure. The old manure spreader has seen several new
developments in recent years to increase its capabilities.
Plow-furrow-cover, like all other forms of land application, needs
careful review by scientists from all disciplines to determine the pol-
lution effect, immediate and long-range, on the surrounding soil,
water, and air.
Techniques are available to collect, store, and treat animal ma-
nure. The one large remaining task and challenge is to determine
the limits of our environment to accept, utilize, or dispose of animal
wastes. It is wonderful to live in a country that has the capabilities
to send men to the moon and back. It is, however, somewhat disturb-
ing to realize that some of our people are standing knee deep in
brown gold to do it. Time and effort will solve the problem; let us
exert the effort and shorten the time.
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296 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
REFERENCES
Agnew, R. W., and Loehr, R. C. 1966. Cattle-manure treatment
techniques. In Management of farm animal ivastes, SP-0366,
pp. 81-84. St. Joseph, Mich.: Am. Soc. Agr. Engrs.
Babbit, H. E., and Baumann, E. R. 1958. Sewerage and sewage
treatment. 8th ed. New York: John Wiley.
Bridgham, D. O., and Clayton, J. T. 1966. Trickling niters as a
dairy-manure stabilization component. In Management of farm
animal wastes, SP-0366, pp. 66-68. St. Joseph, Mich.: Am. Soc.
Agr. Engrs.
Clark, C. E. 1965. Hog waste disposal by lagooning. ]. Sanit. Engrs.
Div. Am. Soc. Civil Engrs. 91 (SA6): 27-46.
Curtis, D. R. 1966. Design criteria for anaerobic lagoons for swine
manure disposal. In Management of farm animal ivastes. SP-
0366, pp. 75-80. St. Joseph, Mich.: Am. Soc. Agr. Engrs.
Dale, A. C., and Day, D. L. 1967. Some aerobic decomposition prop-
erties of dairy cattle manure. Trans. Am. Soc. Agr. Engrs. 10
(4): 546-51.
Dale, A. C., Ogilvie, J. R., Chang, A. C., Douglass, M. P., and Lindley,
J. A. 1969. Disposal of dairy cattle wastes by aerated lagoons
and irrigation. In Animal waste management, pp. 150-59.
Ithaca: Cornell Univ.
Gramms, L. C., Polkowski, L. B., and Witzel, S. A. 1969. Anaerobic
digestion of farm animal wastes (dairy bull, swine, and poultry).
Paper 69-462 presented at annual meeting of Am. Soc. Agr.
Engrs., 22-25 June, Purdue Univ., Lafayette, Ind.
Hart, S. A. 1963. Digestion tests of livestock wastes. /. Water Pol-
lution Control Federation 35 (6): 748-57.
. 1964a. Manure management. Calif. Agr., pp. 5—7. (Dec.)
. 1964b. Thin spreading of slurried manures. Trans. Am.
Soc. Agr. Engrs. 7(1): 22-28.
Hart, S. A., and Turner, M. E. 1965. Lagoons for livestock ma-
nure. /. Water Pollution Control Federation 37(11): 1578-96.
Hart, S. A., Moore, J. A., and Hale, W. F. 1966. Pumping manure
slurries. In Management of farm animal ivastes, SP-0366, pp.
34-38. St. Joseph, Mich.: Am. Soc. Agr. Engrs.
Irgens, R. L., and Day, D. L. 1966. Aerobic treatment of swine
waste. In Management of farm animal wastes, SP-0366, pp. 58—
60. St. Joseph, Mich.: Am. Soc. Agr. Engrs.
Jeffrey, E. A., Blackman, W. C., Ricketts, R. 1965. Treatment of
livestock waste—a laboratory study. Trans. Am. Soc. Agr.
Enqrs. 8(1): 113-17.
Jones, D. D., Day, D. L., and Converse, J. C. 1969. Field tests of
oxidation ditches in confinement swine buildings. In Animal
waste management, pp. 160—71. Ithaca: Cornell Univ.
Loehr, R. C. 1967. Effluent quality from anaerobic lagoons treating
feedlot waste. /. Water Pollution Control Federation 39:384-91.
. 1968. Pollution implications of animal wastes—a forward
oriented review. U.S. Dept. of Interior, Fed. Water Pollution
Control Admin., Robert S. Kerr Water Res. Center, Ada, Okla.
1969. Treatment of wastes from beef cattle feedlots—field
results. In Animal waste management, pp. 225—41. Ithaca:
Cornell Univ.
Ludington, D. C., Bloodgood, D. E., and Dale, A. C. 1969. Storage
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CHAPTER 20 / ANIMAL WASTE MANAGEMENT / 297
of poultry manure with minimum odor. Trans. Am. Soc. Agr.
Engrs. (In press.)
McCarty, P. L. 1964a. Anaerobic waste treatment fundamentals. I.
Chemistry and microbiology. Public Works, pp. 107-12. (Sept.)
. 1964b. Anaerobic waste treatment fundamentals. IV. Proc-
ess design. Public Works, pp. 95-99. (Dec.)
McKinney, R. E., and Bella, R. 1967. Water quality changed in con-
fined waste treatment. Project Completion Report, Kans. Water
Resources Res. Inst., Manhattan.
Miner, J. R., Fina, L. R., Funk, J. W., Upper, R. I., and Larson, G. H.
1966. Stormwater runoff from cattle feedlots. In Management
of farm animal wastes, SP-0366, pp. 23-27. St. Joseph, Mich.:
Am. Soc. Agr. Engrs.
Moore, J. A., Larson, R. E., and Allred, E. R. 1969. Study of the
use of the oxidation ditch to stabilize beef animal manure in
cold climates. In Animal waste management, pp. 172—77.
Ithaca: Cornell Univ.
Norton, T. E., and Hansen, R. W. 1969. Cattle feedlot water quality
hydrology. In Animal waste management, pp. 203-16. Ithaca:
Cornell Univ.
Porges, R., and Taft, R. A. 1964. Principles and practices of aerobic
treatment in poultry waste disposal. Paper presented at the
Natl. Poultry Ind. Waste Management Symp., 20 May, Lincoln,
Nebr.
Reed, C. H. 1966. Disposal of poultry manure by plow-furrow-cover
method. In Management of farm animal wastes, SP-0366, pp.
52-53. St. Joseph, Mich.: Am. Soc. Agr. Engrs.
. 1969. Specifications for equipment for liquid manure disposal
by the plow-furrow-cover method. In Animal ivaste manage-
ment, pp. 114—19. Ithaca: Cornell Univ.
Schmid, L. A., and Lipper, R. I. 1969. Swine wastes, characteriza-
tion and anaerobic digestion. In Animal waste management,
pp. 50-57. Ithaca: Cornell Univ.
Sobel, A. T. 1966. Physical properties of animal manures associated
with handling. In Management of farm animal wastes, SP-
0366, pp. 27-32. St. Joseph, Mich.: Am. Soc. Agr. Engrs.
Stanier, R. Y., Doudoroff, M., and Adelberg, E. A. 1965. The micro-
bial ivorld. 2nd ed. Englewood Cliffs, N. J.: Prentice-Hall.
Ward, J. C., and Jex, E. M. 1969. Characteristics of aqueous solu-
tions of cattle manure. In Animal waste management, pp. 310-
26. Ithaca: Cornell Univ.
Webster, N. W., and Clayton, J. T. 1966. Operating characteristics
of two aerobic-anaerobic dairy manure treatment systems. In
Management of farm animal ivastes, SP-0366, pp. 61—65. St.
Joseph, Mich.: Am. Soc. Agr. Engrs.
Willrich, T. L. 1966. Primary treatment of swine wastes by lagoon-
ing. In Management of farm animal -wastes, SP-0366, pp. 70—
74. St. Joseph, Mich.: Am. Soc. Agr. Engrs. -
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CHAPTER TWENTY-ONE,
WORKSHOP SESSION
T. E. HAZEN, Leader
R. 1. UPPER, Reporter
IN the moderator's opening remarks, he mentioned two pos-
sible areas of discussion that seemed to be suggested from informa-
tion presented in the papers of the Wednesday afternoon session.
One area concerned use of the soil as the ultimate receptor of either
treated or untreated animal wastes. The other was whether the
state of the art is such that more emphasis on broad-based systems
analysis is appropriate.
After much discussion, it was apparent that no one wished to
challenge the general concept of returning livestock wastes to the
land. However, there was ample evidence of anxiety over the many
information gaps that affect intelligent application of the concept.
Much discussion was directed toward the various aspects of nitrate
as a pollutant.
Tolerances of man and domestic animals to nitrates in water
supplies are not well denned. Needs were expressed for much more
specific information. With respect to water for human consumption,
the expressed need for more definite information on tolerance limits
was countered by the assertion that public water supplies must meet
the needs of those with the lowest tolerance. J. E. Box pointed out
that bio-contamination is always associated with blue babies. T. L.
Willrich gave the history of the development of the present 10 mg/1
(N) standard by Comely and cited one controlled study under way
involving children of various ages in care homes. It appears to be
accepted that the criterion now in use for babies and pregnant
women is very conservative for normal adults. Suggestions that the
pressures of a growing population and increased use of fertilizer
may in time indicate the need for special drinking water were in
sharp contrast with other views—namely, that increases in ground-
water nitrates cannot be tolerated regardless of source and that
algal blooms must be precluded in surface waters even if those
waters are not to be used for drinking. A defense was offered for
algae on the basis that they potentially have the ability to remove
T. E. HAZEN is Professor, Department of Agricultural Engineering,
Iowa State University. R. I. LIPPER is Professor, Department of
Agricultural Engineering, Kansas State University.
298
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CHAPTER 21 / WORKSHOP SESSION / 299
nitrates and phosphates, and under some circumstances have other
redeeming characteristics. The assertion that increasingly stringent
water quality standards will be required for the 1980s and beyond
seemed to imply that little is to be gained now by looking for maxi-
mum tolerances in man as influenced by the many variables
involved.
A case was made for the usefulness of more information regard-
ing the influence of nitrates on livestock.
Monitoring of nitrates in groundwater is being done in numerous
localities. High nitrates in well waters often are associated with
feedlots or rural home waste disposal. High nitrates have been found
in wells at depths of 80 to 90 feet. W. H. Walker said that the
Illinois State Water Survey is obtaining background levels of N in
wells at depths to 100 feet and that NO:! levels as high as 1,200 ppm
have been found in Illinois water supplies. Many are in the range of
200 to 300 ppm. N. J. Thul said that the Kansas Department of
Health is sampling wells around large feedlots. Large seasonal
variations (up to 100 ppm) in nitrate levels of effluent from field tile
drains under cultivated land were reported by Willrich. The need
for a broad and extensive interdisciplinary approach to reconcile
potentially conflicting demands for clean water and a highly pro-
ductive agriculture was indicated.
Other questions concerning the returning of livestock wastes to
land were numerous and varied. There are several current research
projects in which very heavy applications of wastes are being in-
corporated into soil. The fate of nitrogen is a common concern, but
the behavior of numerous other possible water, soil, and plant con-
taminants is also being investigated. Interest in management
schemes to maximize nitrogen losses from the soil is evident. Dis-
cussions regarding the salt content of wastes and its effect on soil
structure and water intake rate reflect the complexity of the research
needed. Effects on germination and on plant growth and composition
are being given some attention and appear to require more extensive
examination. Research relating to these questions was cited in the
Northeast Region by P. E. Schleusener; in Nebraska, Texas, and
Colorado by T. M. McCalla; in Kansas by W. L. Powers; in Iowa by
J. Kcelliker; in Georgia by J. E. Box; and in Mississippi by J. B. Allen.
The need for better delineation of objectives to be achieved and
criteria for successful systems was recognized. The emphasis again
was on working from a broad interdisciplinary base, develonment of
better regional planning counsels, and avoidance of parochial con-
cerns through team efforts. Acknowledgment of the rural-urban in-
terface is demonstrated by projects concerned with disnosal of urban
wastes on cropland as well as those directed at minimi/ing the assault
of animal waste management practices on the sensibilities of urban
dwellers.
In the other major area covered by the discussion, it was ad-
mitted that livestock waste management carmot now be planned
with adequate consideration being given to all rther important in-
teracting factors. Continued emphas's toward development of svs-
tem components was defended on the grounds that better com-
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300 / PART 4 / ANIMAL WASTES AS WATER POLLUTANTS
ponents are required as building blocks for systems. On the other
hand, studies of system concepts can indicate where further com-
ponent development is likely to be most productive and it was as-
serted that rudimentary systems analysis would be in order now.
A question was raised concerning importance of the deficiencies
in characterization of wastes with respect to the rations and species
of origin. There was no disagreement with the answer that there is
an obvious relationship, but it is not known how positive the correla-
tion may be. The choices are to become more precise or to accept
the heterogeneity and widen the margin for error.
Other items that were discussed briefly are as follows-, lagoon
criteria, performance, and pollution hazards; pollution tracers and
indicators; potential for beef confinement feeding systems; and allow-
able cost allocations for agricultural pollution control.
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PART FIVE .
AGRICULTURAL POLLUTION IMPLICATIONS
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CHAPTER TWENTY-TWO.
MOVEMENT OF AGRICULTURAL
POLLUTANTS WITH GROUNDWATER
HARRY E. LE GRAND
IN unbiased view of pollution of groundwater from agriculture-
related products would emphasize the fact that numerous rural wells
and springs are polluted. It would also emphasize the fact that only a
very small proportion of rural groundwater is polluted. These facts
are merely a starting point for a general assessment of the degree to
which groundwater may be polluted by agriculture-related products.
An ideal assessment would include an evaluation of cases of
polluted groundwater in relation to unpolluted groundwater to deter-
mine specific causes of pollution. From such an assessment it is
hoped would come simple and concrete guidelines or standards to
prevent pollution.
The following considerations indicate that the development of
simple standards for prevention of pollution of groundwater from
agriculture-related products is difficult.
1. Substances that can become pollutants are numerous and diver-
sified. (Common potential pollutants include animal fecal wastes,
fertilizers, pesticides and associated chemicals, and inorganic
salts.)
2. The environment below ground surface in which agriculture-
related pollutants may occur is complex and generally not easily
determined. (A dry, sandy, clay deposit in a desert might be
acceptable for pollutants whereas a rocky ground with a near-
surface water table could be unacceptable.)
3. The distribution of these potential pollutants ranges greatly from
place to place and time to time. (Wastes from small cow pas-
tures contrast sharply with wastes from large feedlots, and a
single pesticide application on a crop contrasts with repeated
application on some orchards.)
4. The toxicity and attenuation properties of pollutants range great-
ly. (Some pesticides in small quantities are known to be harmful
to some wildlife. The attenuation, or weakening tendencies, of
HAKRY E. LEGRAND is Research Hydrologist, U.S. Geological Survey,
USDI, Raleigh, N.C.
Publication authorized by the Director, U.S. Geological Survey.
303
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304 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
each possible pollutant is dependent on complex factors of its
environment and on its own inherent characteristics.)
Much fruitful research has been done on the behavior of agri-
culture-related products in soils, but the movement of these products
as pollutants downward into the groundwater system has received
less attention. The approach taken here is to discuss briefly some of
the geologic conditions and hydrologic factors that affect the move-
ment of pollutants in the ground environment.
DISTRIBUTION OF POLLUTANTS RELATING TO AGRICULTURE
Increasing attention is being focused on the broad spectrum of
pollution, and the effect of agriculture on environmental quality is
continually being assessed. A symposium presented at the meeting
of the American Association for the Advancement of Science in 1966
(AAAS, 1967) included a group of papers that discussed the effect of
agriculture on the quality of our environment. An excellent summary
report by Wadleigh (1968) discussed wastes in relation to agriculture
and forestry. A group of symposium papers discussing the effects of
pesticides on soil and water was published by the Soil Science Society
of America (1966). At the request of the President of the United
States several government agencies contributed to a report (A Report
to the President, 1969) on the control of agriculture-related pollution.
This latter report listed the following eight pollutants of special con-
cern: sediment, animal wastes, wastes from industrial processing of
raw agricultural products, plant nutrients, forest and crop residues,
inorganic salts and minerals, pesticides in the environment, and air
pollution. All of these except sediment, forest and crop residues, and
air pollution are especially pertinent to the quality of groundwater.
Some brief facts indicating the magnitude of agriculture-related
pollutants at the land surface are stated below.
Animal Wastes
The volume of wastes from livestock and poultry production is
estimated at 1.7 billion tons annually. About one-half of this amount
is produced by animals in concentrated production systems. The de-
gree of concentration and the size of individual production units are
increasing rapidly (A Report to the President, 1969, p. 2). "The daily
wastes from poultry, cattle, and swine alone are equivalent to 10
times the wastes of the human population of the United States"
(Taiganides, 1967, p. 388).
Plant Nutrients
"In 1967, 39 million tons of chemical fertilizers were applied in
the United States and further large increases in use are projected.
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CHAPTER 22 / POLLUTANTS AND GROUNDWATER / 305
The principal nutrients supplied were nitrogen, phosphorus, and
potassium" (A Report to the President, 1969, p. 4).
Inorganic Salts and Minerals
"Though the presence of dissolved salts and minerals in waters
is universal, their presence in detrimental concentrations is generally
associated with part of the irrigated cropland in arid regions of the
country and not with the relatively humid East. Salinity from
natural sources stems mainly from the saline characteristics of soils
and from the geologic formations from which the soils are formed.
The salts have not been leached out because of the scarcity of pre-
cipitation. In agricultural operations in the arid part of the nation,
water is supplied to crops in the necessary quantities to sustain
growth. Concentration of the salts occurs in the soil as a result of
water loss through evaporation and transpiration" (A Report to the
President, 1969, p. 61). The part of the irrigated water reaching the
water table tends to be higher in dissolved salts than it was originally;
there may be as much as a ton of salt per acre-foot of water, as is
the case of water from parts of the Colorado River (Thomas, 1956,
p. 551). Thus, the accumulation of salts in the soil, which may re-
sult in a downward leaching of the salts into the zone of saturation,
tends to deteriorate the quality of groundwater in some irrigated arid
lands.
Pesticides
"Today, in the United States 8,000 manufacturing firms mix
about 500 chemical compounds into more than 60,000 formulations
registered for use as pesticides. In 1964, the U.S. chemical industry
produced 783 million pounds of pesticides. . . ." (Fish, Wildlife, and
Pesticides, 1966, p. 2). Traces of one or more chlorinated hydro-
carbons have been reported in every major river system of the United
States.
BEHAVIOR OF POTENTIAL POLLUTANTS IN THE GROUND
If there were no appreciable attenuation, a potential pollutant
could conceivably pass in sequence through the following parts of
the environment: (1) land surface, (2) zone of aeration (the zone
between the land surface and the water table), (3) the zone of satura-
tion (the groundwater reservoir) to a stream, (4) stream course, and
(5) the sea. Almost never does a pollutant persist throughout the
sequence of travel, and generally it is dissipated in the zone of
aeration.
The great variety of potential agricultural pollutants differ in
their behavior in the ground. The pollutants start to move with water
from precipitation or from solutions containing toxic elements. Pol-
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306 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
lutants in waste solutions are already mobile, but solid wastes must
undergo leaching before pollutants from them become entrained in
subsurface water. The entrainment may be retarded, short-lived, or
complicated by tendencies of pollutants to lose effectiveness by (1)
decay or some other inherent power to decrease potency, (2) sorp-
tion on earth materials, and (3) dilution through dispersion and dif-
fusion. Assessing the degree to which pollutants will become at-
tenuated and predicting the limits of individual polluted zones are
central objectives.
Decay
In the sense used here decay refers to any of the mechanisms by
which materials foreign to the ground may be destroyed, inactivated,
or dissipated as to toxicity. Some pollutants degrade and lose their
potency with passing time; others degrade in contact with oxgyen,
particularly on the land surface, in surface water, or in the zone of
aeration above the water table. Animal wastes degrade in an oxygen-
rich environment that favors biological decomposition. Some pesti-
cides are broken down by microorganisms in the soil, but others
(Alexander, 1967, p. 335) resist biodegradation.
Sorption
Although moving in the same direction as water, some pollutants
move slowly or scarcely at all as they are physically retained by, or
react chemically with, earth materials. The extent to which pol-
lutants are retained depends on the character of the pollutant and on
that of the earth materials through which they move. Clays tend to
retain, by ion exchange or some other sorptive mechanism, many
pollutants better than do sands. Dense rocks in which permeability,
and thus the sorbing surface, is restricted to fractures and solution
openings have poor sorption characteristics, and in these rocks the
water and the entrained pollutants may move at about the same rate.
Dilution
Almost all agriculture-related pollutants mix to a considerable
degree in water. Dispersion and dilution are commonly favorable
considerations, at least at a certain stage or position of pollutant
movement. However, dispersion is not desirable where dilution is in-
sufficient to lower the concentrations of certain pollutants to limits
acceptable for organisms that use the water. For example, where
concentrated toxic pollutants leak to the ground, consideration may
be given to recovering and containing them before they disperse into
the ground.
A method of evaluating collectively all aspects of attenuation
has not been developed. Precise values for sorption and dilution in
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CHAPTER 22 / POLLUTANTS AND GROUNDWATER / 307
the environment are difficult to determine. Generally we do not
separate our reliance on sorption, on dilution, or on "delay and
decay" in the ground before the pollutant reaches points of water
use. Yet, a crude evaluation of each method of attenuation in each
case of possible pollution might be helpful.
HYDROGEOLOGIC FRAMEWORK
A potential pollutant at the ground surface may be considered
to be in a geologic environment of solid earth materials that include a
complex arrangement of soils and rocks. It is also in a hydrologic
environment that may give it mobility as some water from precipita-
tion moves into the zone of aeration and down into the zone of satura-
tion. Thus, the hydrogeologic setting represents an environment in
which two opposing tendencies are at work—the tendency for a pol-
lutant to move with subsurface water and the opposing tendency for
it to be almost immobile or weakened by a combination of dilution,
sorption on earth materials, or some "die-away" mechanism. The
great range in geologic and hydrologic conditions prevents good rule-
cf-thumb techniques for determining the safe distribution of agricul-
ture-related products at the land surface.
The soil zone is the "action zone" where fertilizers, manure, and
pesticides may start to become pollutants of groundwater. It is the
action zone for biodegradation and other attenuation methods. The
chemical and biological character, texture, permeability, and thick-
ness of the soil zone are important features.
Beneath surface soils in some places are unconsolidated sedi-
mentary materials of clay, silt, and sand. In other places hard, dense
rocks underlie soils. Rocks at considerable depth may not be sig-
nificant because they lie below the paths of most ground-surface
pollutants.
Permeability is an important characteristic because it controls
the rate of movement of water and pollutants that might be with it.
The permeability of some clays may be many hundreds of times less
than that of some sands. Zones of greater permeability tend to paral-
lel, or coincide with, rock formational boundaries even if the rocks
are appreciably inclined. Differences of permeability in the horizontal
field, although common, are in many cases more gradual than in the
vertical field. The point to be made is that water and included waste
will tend to take preferred paths, flowing readily through permeable
zones and shunning or flowing with difficulty through relatively
impermeable materials.
The water table is an important consideration of groundwater
pollution, especially in view of the ease of attenuation of most pol-
lutants xvhere the water table is deep and where the overlying zone
of aeration is composed of sands, silts, and clavs. The frequency of
precipitation in humid regions is sufficient to keep the water table
relatively close to the ground surface in areas of moderate per-
meabilities, and the consequent mounding of water beneath inter-
stream areas causes a continuous subsurface flow of water to nearby
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308 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
perennial streams. Thus one can get a general idea of the gross
direction of movement of groundvvater in humid regions; in arid re-
gions, however, the areas of natural groundwater discharge are more
widely scattered, and the general movement of water may be less
discernible. In arid regions some reaches of most streams lose water
—that is, water from the streams may seep into the ground as
opposed to the gaining type of stream in humid regions.
In many cases of pollution, the movement of water in the
ground has been altered by man's activities, such as pumping of
wells or adding liquids to the ground. Pumping of a well causes a
cone of depression on the water table, resulting in a flow of water
toward the well from the surrounding area. Opposite hydrologic
conditions result when liquids are added to the ground in one place,
as a mound on the water table is developed and groundwater moves
outward from the spot. Knowledge or inferences about earlier condi-
tions may guide decisions about remedial action on some pollution
problems.
POLLUTION PATTERNS IN HYDROGEOLOGIC SETTINGS
Fertilizers and pesticides are spread usually over the land sur-
face in their conventional use, and occasional applications for both,
rather than continual applications, are the rule. Both the lack of
concentration and the lack of continual application tend to weaken
the ability of these possible pollutants to move downward with in-
filtrating water through the soil zone or through the entire zone of
aeration to the water table.
Of the fertilizer nutrients, phosphate and nitrate are the ions of
chief concern as to possible pollution of water resources. Phosphorus
tends to be sorbed by soils so well that it is rarely a serious threat.
Nitrate is a common constituent in groundwater, generally in pro-
portions of no more than a few milligrams per liter. In fact, the
average sample of groundwater in the humid southeastern part of
the United States has less than one milligram per liter of nitrate. Yet,
in local areas and in certain groundwater systems the nitrate content
averages several milligrams per liter. It may originate from natural
sources, livestock feeding operations, sewage disposal systems, legume
residues, manures, or excessive use of chemical fertilizers. It is dif-
ficult to single out the source of nitrate in groundwater, but Smith
(1967, p. 184) points out that leachates from highly fertile, un-
fertilized agricultural lands may have a higher content of plant
nutrients than the percolates from nearby fertilized, well-managed
cropland low in natural fertility. Nitrate and chloride are good pre-
cursors of pollution, and an increase in these ions with time may aid
planning in avoiding serious pollution. With the exception of isolated
cases, there is little evidence to support statements that fertilizer
nutrients are polluting water supplies (Smith, 1967, p. 185). A special
studv of a fertilized terrain in southwestern Wisconsin (Minshall et
al., 1969, p. 713) confirms this view; it was found after 2 years of
data collecting that water of streams during their low-flow period
(representing outflow of groundwater) in this region appeared to be a
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CHAPTER 22 / POLLUTANTS AND GROUNDWATER / 309
relatively unimportant carrier of plant nutrients. With excessive and
improper use, however, in the future nitrates could become a problem
when excess nitrogen is added to some soils.
Analyses of groundwater for pesticide content are relatively rare;
most of the analyses are related to local research programs not yet
completed or are from isolated samples of water from wells near
places where concentrated pesticides may have spilled to the ground.
The absence of a systematic sampling and monitoring program of
groundwater is probably based on the assumption that the soil zone
and zone of aeration are effective in attenuating pesticides above the
water table. The work of Sheets (1967), Alexander (1967), and
other workers indicates the tendency for the bulk of pesticides to be
degraded, volatilized, or fixed on soils. That microbial decomposition
of pesticides is less rapid in subsoil than in surface soil appears to be
a valid assumption that should be investigated (Sheets, 1967, p. 322).
Even in the subsoil, sorption is still effective, as indicated by research
on DDT (Scalf et al., 1968).
Some groundwater samples from Arkansas and Mississippi in
the Mississippi River Delta were analyzed for pesticide residues as a
result of a research project undertaken by the USDA (ARS 81-13).
This study reports analyses made in 1964 and indicates that most of
the well water sampled contained no detectable pesticide residue.
However, detectable residues were identified in a few samples, gen-
erally in quantities of only a fraction of a microgram per liter. At
the time the report was completed, the presence of the residues in
the well water was not explainable. It should be noted that none of
the wells contained pesticide residues throughout the year. This
study of pesticides in the Mississippi River Delta serves to show the
difficulty of evaluating the possibility of contaminating groundwater.
Iverson (1967, p. 161) reports that analyses "of hundreds of samples
of water have produced evidence that neither deep nor shallow wells
are being contaminated by insecticides if the well is constructed in
such a manner as to provide water fit for human consumption."
Evidence from different sources suggests the general freedom of
groundwater from pesticides, but a monitoring program to determine
the distribution of pesticides in groundwater seems justified.
There are certain conditions that could readily lead to local
pollution of groundwater by pesticides and related chemicals. Where
such materials are dumped on the ground in concentrated form, es-
pecially near shallow wells or in areas where the soil is thin or
highly permeable, pollution of groundwater could be serious. Soils
are thin in many areas underlain by limestone, where rolling sink-
hole topography results in quick drainage of surface water into
caverns. In some limestone terranes the groundwater moves rapidly
to streams, and pollutants have little chance to be attenuated
(Deutsch, 1963, p. 33). Attenuation of pollutants is much better
where the pollutants are in contact with the ground only occasionally,
as with agricultural pesticide use.
Although there is a tendency for animal organic wastes to become
more localized each year, both animal and human wastes in rural
areas are much more dispersed than those in urban areas. Thus,
unlike procedures in urban areas where organic wastes are generally
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310 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
contained, diluted with water, transported, and treated, the waste-
handling procedures in rural areas result in wide distribution to the
ground; the percentage of water added to wastes in rural areas is
generally much less than that in urban areas. It is difficult to assess
the potential of rural organic wastes to pollute water. Overland run-
off can leach wastes and result in stream pollution. There is vertical
leaching into the ground environment of animal and human wastes.
Gillham and Webber (1968) reported a significant increase in the
nitrogen content in the groundwater as it passed beneath a barnyard.
Two counter tendencies prevail. The tendency for pollution from
leached wastes to move downward and to become entrained with the
subsurface water is mostly offset by the tendency of the waste mate-
rials to be attenuated by degraduation in the soil, by sorption, and by
dilution. Hence, pollution of groundwater is less common than
might be expected in view of the widespread occurrence of surface
contaminants. Yet, serious problems do exist. The potential for pol-
luting groundwater is great where concentrated wastes, as at feed-
lots, are exposed to thin soils on cavernous limestone formations or
to thin or sandy soils on fractured rocks.
Where pollutants escape attenuation by sorption and decay in
the zone of aeration, attenuation in the underlying zone of satura-
tion may be chiefly by dilution in groundwater. As might be expected
in the groundwater reservoir, the polluted zone is normally more
FIG. 22.1. Generalized block-diagram, showing isolated polluted
zones at the land surface (dots in block on right) and the relative ex-
tent to which pollution is carried downward to the zone of saturation
in block on left. Sites A, B, and C represent pollution concentrations,
such as feedlots, great enough to pass through the zone of aeration
and along the top of the zone of saturation for some distance toward
the surface stream.
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CHAPTER 22 / POLLUTANTS AND GROUNDWATER / 311
pronounced at the water table than at greater depths, and the pol-
luted zone tends to be elongated in the direction of groundwater
movement. Patterns of polluted zones on the water table have been
described schematically by LeGrand (1965) and are shown in Figure
22.1. Although zones of pollution from agriculture-related products
have rarely been described, their patterns on the water table are
similar to patterns formed by industrial pollutants. A large but com-
monly shaped polluted zone (Fig. 22.2) resulted from waste-disposal
practices at a chemical factory in Colorado (Walker, 1961); the map
shows the movement of chlorates and 2,4-D-type compounds, as well
as the anticipated area of influence from waste basins. Very rarely
would a contaminated groundwater zone in agricultural areas be
as large as that shown in Figure 22.2, but the "down-gradient" shape
is typical.
CONCLUSIONS
The volume of groundwater polluted by plant nutrients, animal
wastes, and pesticides appears to be small. Admittedly, there are
-5000
EX PLANATION
Anticipated area of influence
Chlorate toxicity
2, 4-D-type toxicity
Waste basins
— Contours on water
(feet above sea
level)
FIG. 22.2. Patterns of polluted groundwater formed from seepage of
chemicals from waste basins. (Modified after Walker, 1961, p. 492.)
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312 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
numerous cases of farm wells being polluted, and numerous small
polluted zones of water occur in the upper part of the zone of
saturation. Sufficient safeguards are available to minimize ground-
water pollution to the extent that good agricultural practices should
not be deterred.
The zone of aeration above the water table, which normally
contains in its upper part the soil zone, attenuates almost all of the
foreign bodies that are potential pollutants of the underlying ground-
water. Chemical fertilizers, animal wastes, and pesticides vary great-
ly in their tendency to degrade in ground environments. They all
degrade better under a set of hydrogeologic conditions. The follow-
ing environmental factors tend to reduce the chances of pollution
of water from wells and springs:
1. A deep water table, which (a) allows for sorption of pollutants on
earth materials, (b) slows subsurface movement of pollutants,
and (c) facilitates oxidation or other beneficial "die-away" effects.
2. Sufficient clay in the path that pollutants will move so that re-
tention or sorption of pollutants is favorable. (However, excessive
clay may result in poor surface permeability, thereby allowing
much water and pollutants to move overland to surface streams.)
3. A gradient of the water table beneath a waste site away from
nearby wells.
4. A great distance between wells and wastes so that advantages of
the above factors can accumulate.
Dispersion has been a major factor in minimizing the pollution
of groundwater in agricultural regions of the United States. In their
conventional uses both fertilizers and pesticides have been widely
but thinly applied. Both human and animal wastes have caused
only minor pollution problems until recent years, but the increasing
concentrations of animal wastes in large feedlots is a matter of
growing concern. Disposal of containers of pesticides and other
toxic chemicals in rural areas by design or accident will pose ques-
tions of the possibility of groundwater pollution.
Soils maps and results of hydrogeologic studies should furnish
a good background for evaluating the potential of certain agriculture-
related products to pollute groundwater. Yet no magic or simple
quantitative system for predicting accurately the fate of the variety
of pollutants in the ground environment is likely to be developed
soon. Although extremely unfavorable ground conditions are easy
to determine, most earth materials have the capacity to attenuate
pollutants to some degree. The exercise of good judgment in manag-
ing agriculture-related products that can become pollutants of
groundwater is essential.
REFERENCES
Alexander, Martin. 1967. The breakdown of pesticides in soils. In
Agriculture and the quality of our environment, ed. N. C.
Brady, pp. 331-42. Norwood, Mass.: Plimpton Press.
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CHAPTER 22 / POLLUTANTS AND GROUNDWATER / 313
American Association of Advancement of Science. 1967. Agricul-
ture and the quality of our environment, ed. N. C. Brady, Nor-
wood, Mass.: Plimpton Press.
Deutsch, Morris. 1963. Ground-water contamination and legal con-
trols in Michigan. U.S. Geol. Survey Water-Supply Paper 1691.
Gillham, R. W., and Webber, L. R. 1968. Groundwater contamina-
tion. Water Pollution Control 106 (5).
Iverson, L. G. K. 1967. Monitoring of pesticide content in water in
selected areas of the United States. In Agriculture and the
quality of our environment, ed. N. C. Brady, pp. 157-62. Nor-
wood, Mass.: Plimpton Press.
LeGrand, H. E. 1965. Patterns of contaminated zones of water in
the ground. Water Resources Res. 1 (1): 83-95.
Minshall, N. M., Starr, Nichols, and Wetzel, S. A. 1969. Plant nu-
trients in base flow of streams in southwestern Wisconsin.
Water Resources Res. 5 (3): 706-13.
Scalf, M. R., Hauser, V. L., McMillion, L. G., Dunlap, W. J., and
Keeley, J. W. 1968. Fate of DDT and nitrate in ground water.
Robert S. Kerr Water Res. Center, Ada, Okla., and Southwestern
Great Plains Res. Center, Bushland, Tex., Spec. Publ.
Sheets, T. J. 1967. Pesticide buildup in soils. In Agriculture and the
quality of our environment, ed. N. C. Brady, pp. 311-30. Nor-
wood, Mass.: Plimpton Press.
Smith, G. E. 1967. Fertilizer nutrients in water supplies. In Agri-
culture and the quality of our environment, ed. N. C. Brady,
pp. 173-86. Norwood, Mass.: Plimpton Press.
Soil Science Society of America. 1966. Pesticides and their effects
on soils and water. ASA Spec. Publ. 8.
Taiganides, E. P. 1967. The animal waste disposal problem. In
Agriculture and the quality of our environment, ed. N. C. Brady,
pp. 385-94. Norwood, Mass.: Plimpton Press.
Thomas, Harold E. 1956. Changes in quantities and qualities of
ground and surface waters. In Man's role in changing the face
of the earth, ed. William L. Thomas, pp. 542-63. Chicago:
Univ. Chicago Press.
U.S. Dept. of Agriculture. 1966. Monitoring agricultural pesticide
residues. ARS-81-13.
U.S. Dept. of Agriculture. 1969. Control of agriculture-related pol-
lution. A report to the President. Submitted by the Sec. of
Agr. and the Dir. of the Office of Sci. and Technol.
U.S. Dept. of Interior. 1966. Fish, wildlife and pesticides. U.S.
Fish and Wildlife Serv. Unnumbered pamphlet.
Wadleigh, C. H. 1968. Wastes in relation to agricidture and for-
estry. USDA Misc. Publ. 1065.
Walker, T. R. 1961. Ground-water contamination in the Rocky
Mountain arsenal area. Denver, Colorado. Eidl. Geol. Soc. Am.
72:489-94.
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CHAPTER TWENTY-THREE.
EFFECTS OF AGRICULTURAL
POLLUTION ON EUTROPHICATION
D. E. ARMSTRONG and G. A. ROHLICH
£• UTROPHICATION refers to the process of enrichment of wa-
ter with nutrients (Stewart and Rohlich, 1967). An obvious effect
of eutrophication is an increase in the biomass which can be sup-
ported in a body of water. Although the increase in yield of a crop
after fertilization is desirable in terrestrial situations, the effects of
eutrophication of waters are often undesirable. Generally the
aesthetic value of a lake is lowered through excessive growth of
aquatic weeds and algae and production of floating algal scums
which are a nuisance to those who use the water for recreational pur-
poses. Other effects include undesirable odors and tastes, and im-
pairment of water treatment operations—for example, through clog-
ging of filters by algae.
It should be recognized that lake eutrophication is a natural
process of lake maturation. Precipitation and natural drainage
contribute nutrients which support and enhance the growth of
phytoplankton and littoral vegetation. However, the acceleration
of eutrophication as a result of man's activities in altering the land-
scape through agricultural development, urbanization, and waste
discharge is of major concern.
While lake eutrophication involves enrichment with nutrients,
the stage or rate of lake eutrophication is not controlled solely by
the quantities of nutrients present or entering the receiving body
of water. The interrelationships of climatic, physical, chemical, and
biological factors which affect lake metabolism are highly complex.
As illustrated by Rawson (Fig. 23.1), the morphology of the basin,
geological characteristics of the area, temperature, nutrient input,
and many other factors influence the metabolism of a lake. Because
of the complex interrelationships involved, establishing reliable
measurements of lake eutrophication rate and stage has been a
major problem (Fruh et al., 1966).
Interest in control of eutrophication has focused on limiting
D. E. ARMSTRONG is Assistant Professor of Water Chemistry, Uni-
versity of Wisconsin. G. A. ROHLICH is Director, Water Resources
Center, and Professor of Sanitary Engineering, University of Wis-
consin.
314
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 315
.Geographic Location_
X
Topography
Latitude
Longitude
' Altitude
Climate
Human
Influence
Geological
Formation
Sewage
Agriculture
Mining
Composition
of Substrate
Shape of Basin
Primary Nutritive /^Drainage Area Depth
Materials
Light pene-
tration
Heat Penetration
and Stratifica-
tion
Oxygen Penetra-
tion and utili-
zation
Development
of Littoral
Region
Nature of •*— Inflow of
Bottom Allochth.
Deposits Materials
Seasonal Cyclo
Circulation . Stag-
nation , Growing
Season
'Trophic Nature of the Lake'
Amount, composition and distribution of plants
and animals. Also rates of circulation.
"l-l J 1' 'I "
Productivity
FIG. 23.1. Chart suggesting the interrelations of factors affecting the
metabolism of a lake. (Rawson, 1939.)
the amounts of nutrients entering the water. The success of this
approach depends on whether the available nutrient supply can be
reduced to the extent that growth of aquatic plants is limited.
Nutrients which have received the most attention are nitrogen and
phosphorus because, following carbon, they are required in the
greatest amounts for the production of green plants.
Importantly, the amounts of nitrogen and phosphorus available
to aquatic plants in lakes depend not only on the amounts entering
the body of water but also on the chemical, biochemical, and physi-
cal processes occurring within the lake as shown in Figure 23.2
(Armstrong et al., 1969). The available nitrogen and phosphorus
pool (mainly the dissolved inorganic nitrogen and phosphorus com-
partment) is regulated by a number of interrelated processes. For
example, uptake or release of available nutrients by the bottom sedi-
ments may occur, depending on sediment properties and environ-
mental conditions. Microorganisms may compete with plants for
available nutrients. It should be emphasized that both quantities in
compartments and rates of interchange among compartments are
important. For example, rapid exchange of nutrients between the
sediments and water might supply sufficient quantities for plant
growth even at low concentrations of nutrients in the lake water.
FACTORS CONTROLLING NITROGEN AND PHOSPHORUS TRANS-
PORT IN AGRICULTURAL DRAINAGE
The forms and chemistry of nitrogen and chemistry of nitrogen
and phosphorus in soils have been discussed previously and will be
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316 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
N.P
GAINS
FIG. 23.2. Major components of the nitrogen and phosphorus cycles
in lakes. (Armstrong et al., 1969.)
reviewed only briefly here (see review by Biggar and Corey, 1969).
Most of the nitrogen in soils (perhaps more than 95% of the
total soil nitrogen) is organic. Much of the organic nitrogen (about
50%) is present in amino form. The main inorganic forms are
nitrate and ammonium; nitrite is usually present only in small
amounts, though a small portion of the total soil nitrogen, nitrate,
and ammonium is of primary importance because it is in the form
of nitrogen utilized by plants. Quantities of ammonium and nitrate
depend mainly on the processes of organic nitrogen mineralization
and inorganic nitrogen immobilization, and soil organic nitrogen or
organic matter contents provide a good indication of the nitrogen
fertility of the soil.
Phosphorus in soils exists in inorganic and organic forms. The
inorganic phosphorus content varies from about 25 to 97% of the
total and is in the range of 50 to 75% for many soils. Total phos-
phorus ranges from 100 to 2,000 ppm and is often about 1,000 ppm.
Dissolved inorganic phosphorus is the form directly available to
plants but organic phosphorus is available through conversion to
inorganic phosphorus. The amount of dissolved inorganic phos-
phorus in the soil solution is low, usually about 0.01 to 0.1 ppm,
due to adsorption of phosphorus by the iron, aluminum, and calcium
components of the soil.
Water reaching the soil surface is disposed of by (1) surface
runoff. (2) groundwater runoff (interflow), (3) deep percolation,
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 317
(4) storage, and (5) evaporation and transpiration (Biggar and Corey,
1969). Of these, the first three—namely, surface runoff, ground-
water seepage, and percolation to perched water tables or deeper
aquifers—contribute to eutrophication by transporting nutrients to
streams and lakes. Surface runoff may directly enter streams and
subsequently lakes. Some of the water that enters the soil drains
downslope and may reappear at a lower elevation as surface water
or seepage. Water percolating to the groundwater may transport
nutrients to rivers and lakes which receive a major portion of their
water from groundwater flow. According to Biggar and Corey (1969),
irrigation, which involves a recycling of water derived from runoff,
seepage, and percolation, often increases the amounts of nutrients
transported to lakes and streams by these waters.
The amounts of nutrients transported in agricultural drainage
are determined in part by the chemical forms of the nutrients and
the processes controlling their retention in the soil. Runoff water
carries nutrients in both dissolved and particulate forms, while
water percolating through the soil generally carries only dissolved
forms. Because inorganic phosphorus is retained more strongly
than inorganic nitrogen by soil particles, the forms of nitrogen
and phosphorus transported differ appreciably for runoff and per-
colate waters. Ammonium and particularly nitrate are quite soluble
and tend to move downward in the soil with percolating wrater,
thereby lowering the amounts at the soil surface. Since runoff wa-
ters tend to transport forms located near the soil surface, ammonium
and nitrate are carried in runoff waters in dissolved or paticulate
form to a lesser extent than are the more insoluble nutrients. Due
to the low anion exchange capacity of soils and the high solubility
of nitrate, the downward movement of nitrate with percolating
waters is quite rapid. Thus, the extent to which nitrate is leached
depends to a large extent on the quantity of water percolating
through the soil and the degree to which nitrate levels are in excess
of plant and microbial needs. Although ammonium is soluble, the
downward movement of ammonium is retarded by retention at
cation exchange sites. Furthermore, conversion of ammonium to
nitrate in soils through nitrification is generally quite rapid.
Inorganic phosphorus tends to be strongly retained by soil par-
ticles, and phosphorus received by the soil as commercial fertilizer,
plant residue, and manure tends to remain at the soil surface, there-
by enhancing the possibility of transport by runoff in particulate
and soluble forms. Biggar and Corey (1969) have suggested that
due to the low mobility of phosphorus in soils, application of phos-
phorus to the soil surface will tend to saturate the phosphorus ad-
sorption sites and cause the concentration of phosphorus in solution
near the soil surface to be relatively high. Some of the phosphorus
in solution would tend to move downward but would be rapidly
adsorbed at the undersaturated adsorption sites beneath the surface.
However, at the surface, phosphorus in solution would be maintained
at a relatively high concentration and the phosphorus concentration
in runoff waters in contact with these surfaces might be relatively
high. Whether the dissolved phosphorus would remain in solution
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318 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
would depend on the phosphorus adsorption capacity of the sus-
pended soil particles and stream sediments in contact with the
runoff water.
Both organic nitrogen and organic phosphorus as well as inor-
ganic phosphorus are of low mobility in soil and are likely trans-
ported to a large extent in particulate form in runoff waters. How-
ever, because the amount of organic nitrogen in soil is high as
compared to inorganic nitrogen, quantities of soluble organic nitro-
gen transported may be significant relative to amounts of inorganic
nitrogen. Particulate forms are generally of less interest than dis-
solved forms regarding their effects on the receiving water due to
the lower plant availability of these forms and the possibility that
the particulate material will settle to the bottom of streams or lakes.
However, it should be recognized that the new environment, for
example an anaerobic lake bottom, may markedly increase the
mobility of nutrients contained in these particles. On the other
hand, eroded soil particles transported to streams or lakes may de-
crease the available nutrient supply in the water. For example,
phosphorus-deficient soil particles entering a lake may remove phos-
phorus from solution by adsorption and transport the adsorbed
phosphorus to the lake bottom.
In summary, it is generally expected that inorganic nitrogen is
transported mainly as nitrate by percolating waters, although the
amounts of ammonium and nitrate carried in runoff waters may be
highly significant in terms of the receiving water. Similarly, the
largest amount of phosphorus is likely transported in particulate
form in runoff waters, but the amount of dissolved phosphorus in
runoff water may be of equal or greater importance even though
lower in quantity. Obviously these statements are highly generalized
and will not apply in many situations. An important example is the
situation in which the soil is frozen. In this case, soluble and par-
ticulate forms of both nitrogen and phosphorus would be carried in
surface runoff.
Because concern over the quality and the nutrient content of
agricultural drainage has developed only recently, relatively few
TABLE 23.1. Nitrogen and phosphorus content of waters in surface and sub-
surface drains and in shallow wells.
Constituent Surface Drain Subsurface Drain
NO3--N
Dissolved P . . . .
Total P
NOr-N
Dissolved P . . . .
Total P
0.8
0.19
0.27
1.9
0.20
0.26
mg/1
Irrigation Season
2.5
0.22
0.28
Nonirrigatioji Season
2.5
0.23
0.26
Shallow Well
2.3
0.12
0.16
0.16
0.08
0.10
Source: Sylvester and Seabloom (1962) as reported by Biggar and Corey
(1959).
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 319
TABLE 23.2. Constituents in runoff waters from a 1.45-acre winter wheat
field near Coshocron, Ohio.
In Runoff
Constituent Range Average In Rainfall
(mg/l)
Suspended solid; 5-2074 313.0 11.7
Total N 2.2-12.7 9.0 1.17
Inorganic N 0.2-8.2 5.0 0.86
Total hydrolyzable P 0.08-1.07 0.6 0.03
Source: Weibel et al. (1966) as reported by Biggar and Corey (1969).
investigations have involved quantitative evaluation of the factors
controlling the amounts of nitrogen and phosphorus reaching
streams and lakes from agricultural sources. However, some data
are available which are useful in considering the amounts of nu-
trients transported in this manner.
Sylvester and Seabloom (1962) studied the amounts of nutrients
carried to surface drains, subsurface drains, and shallow wells for
irrigated and nonirrigated situations in the Yakima Basin (Table
23.1). Surface drains should reflect surface runoff, subsurface drains
the nutrients leached to shallow depths, and shallow wells the
nutrients carried in percolating water to the groundwater. As ex-
pected, the amount of phosphorus carried to the groundwater was
small, although amounts appearing in shallow drains were compar-
able to the amounts in subsurface drains. The quantities of nitrate ap-
pearing in subsurface drains and shallow wells reflected the mobility
of nitrate in percolating waters. Recycling of the water through
irrigation tended to increase the amounts of nutrients in the
groundwater.
Weibel et al. (1966) measured the nutrient concentrations in
runoff waters from a small wheat field in Ohio (Table 23.2). It is
of interest to note the relatively high concentrations reported for
runoff, the range in amounts of suspended solids, and the relatively
large amounts of materials in the rainfall.
Further indication of the importance of runoff is obtained from
the results of Duley and Miller (1923) shown in Table 23.3. Annual
TABLE 23.3. Annual nitrogen and phosphorus content of runoff and eroded
material from a shelby loam soil of 3.6% slope.
Pounds per Acre
Cropping System Total N NOr-N Total P
Not cultivated
Spaded 8" deep
Bluegrass sod
Wheat
Rotation — corn,
wheat, clover
Corn annually
99.0
74.0
0.6
30.0
6.0
40.0
1.38
0.56
0.07
0.32
0.02
0.02
48.0
33.0
0.1
11.0
2.0
8.0
Source: Duley and Miller (1923) as reported by Biggar and Corey (1969).
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320 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
TABLE 23.4. Estimated amounts of nitrogen and phosphorus in agricultural
drainage.
Pounds per Acre of Land per Year
Drainage Area Inorganic N Organic N Inorganic P Organic P
Lake Monona 4.4 1.6 0.06
Lake Waubesa 4.9 1.8 0.10 0.29
Lake Kegonsa 6.4 1.8 0.10 0.31
Source: Sawyer (1947).
amounts transported ranged from 0.6 to 99 Ib/acre of total nitro-
gen, 0.02 to 1.38 Ib/acre of NO3-N, and 0.1 to 48 Ib/acre of total
phosphorus. Of particular interest is the marked effect of the crop-
ping system and the low amount of NO3-N transported relative
to total nitrogen.
From another point of view, Sawyer (1947) estimated the
amounts of nitrogen and phosphorus carried from the watershed
to three Wisconsin lakes based on analysis of one tributary to each
lake (Table 23.4). The estimated pounds of nutrients lost per acre
of land per year were from 4.4 to 6.9 for inorganic nitrogen, 1.6 to
1.8 for organic nitrogen, 0.06 to 0.10 for inorganic phosphorus, and
0.29 to 0.31 for organic phosphorus. Estimates of nutrient losses
for harvested areas of the United States (Table 23.5) reported by
Lipman and Conybeare (1936) were 4 to 6 times greater for nitrogen
and 4 to 40 times greater for phosphorus than the values estimated
by Sawyer (Table 23.4). Leaching estimates were based on lysimeter
and river analysis, while erosion estimates involved amounts of
eroded material lost at various locations and the nutrient content of
the soil in the corresponding region.
CONTRIBUTION OF AGRICULTURAL DRAINAGE TO THE NITRO-
GEN AND PHOSPHORUS STATUS OF WATERS
Although eutrophication of surface waters through transport
of nutrients from surrounding lands is a natural process, primary
concern is focused on whether the activities of man are increasing
the amounts of nutrients transported in agricultural drainage as well
as from other sources and whether practices can be implemented
which will lessen the nutrient influx and thereby preserve the quality
of our waters.
The relative contribution of agriculture to the nutrient budget
of a lake depends on types of activities occurring in the drainage
basin of the lake. For example, lakes located in rural areas may be
influenced primarily by agricultural drainage, while the effect of
extensive urban development in the drainage basin may be to lower
the relative importance of agricultural drainage. Furthermore, the
types of agricultural practices and activities also influence the qual-
ity of agicultural drainage, and consequently the relative role of
agriculture in eutrophication. For example, animal feeding and soil
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 321
TABLE 23.5. Loss of plant nutrients from harvested crop areas in the U.S.A.,
1930.
Intertilled crops
Leaching
Erosion
Annual crops not intertilled
Leaching
Erosion
Biennial and perennial crops
Leaching
Erosion
Pounds
N
17 1
48 1
32.5
11 1
23.0
24 2
per Acre
P
21 0
4 9
10 6
per Year
K
39 1
280 7
37 6
65 0
141 1
Source: Lipman and Conybeare (1936) as reported by Biggar and Corey
(1969).
management practices can have a marked effect on the quality of
agricultural drainage.
An indication of the effect that certain agricultural activities
and management practices can have on the quality of agricultural
drainage is shown in the following examples.
Animal wastes are one of the largest sources of agricultural
wastes (Loehr, 1969), and concern has been focused on the impact
of these wastes on water quality, particularly the amount of nitrogen
transported in runoff and percolate waters from animal feedlots
which represent a concentrated source of these wastes. The survey
of well waters in Missouri conducted by Smith (1964) seemed to
show a relation between animal population and the nitrate content
of the groundwater.
Stewart et al. (1967) compared the nitrogen and phosphorus
contents of the surface groundwater beneath feedlots to that beneath
nearby irrigated fields (Table 23.6). Their results showr that concen-
TABLE 23.6. Concentrations of constituents in surface of groundwater be-
neath four feedlots and adjacent irrigated fields.
MG/L in Water of
Depth to Water Total
Table NO,--N NH4+-N dissolved P Organic C
Feedlot
Irrigated
"Peedlot
Irrigated
Feedlot .
Irrigated
Feedlot .
Irrigated
field . .
field . .
field . .
field . .
(meters)
10
10
5
3
4
3
11
11
8.
0.
18.
31.
21.
8.
1.
18.
fi
1
0
0
0
5
1
.0
o
0,
5
0.
5
0.
38
0
,1
,0
7
,1
8
.0
,0
.4
0
0.
0
0.
0,
0.
1
0
.25
06
36
04
,22
,01
,3
.05
130
18
130
12
90
9
170
26
Source: Stewart et al. (1967).
-------
322 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
trations of nitrate, ammonium, phosphorus, and organic carbon
were generally higher beneath the feedlots. However, because of the
greater area occupied by irrigated lands, it was suggested that for
this area irrigated lands were contributing more nitrate to the
groundwater than were the feedlots.
Although attention is usually focused on runoff and percolates,
the recent results of Hutchinson and Viets (1969) indicate that
volatilization of ammonia from feedlots can cause transport of sig-
nificant quantities of nitrogen to nearby surface waters (Table 23.7).
Depending on feedlot size and distance from the feedlot, about 4 to
35 kilograms of NH3-N/hectare (one-half of the values obtained
by adsorption of ammonia in acid traps) were transported to nearby
surface waters. These amounts were much larger than the quantity
of NH4-N contained in precipitation (the precipitation values shown
in Table 23.7 are for a 3-month period).
The results of Weidner et al. (1969) recorded in Table 23.8
indicate the effect that soil management and crop rotations can
have on the amounts of nutrients carried in runoff waters. Improved
management reduced nitrogen in runoff by about 63% and phos-
phorus by 70%. These values were estimated from correlations
between the quality parameters and total solids in the runoff,
and it is seen that the main effect of improved management was to
reduce the total solids transported in the runoff. Improved manage-
ment primarily involved contour tillage, liming of the soil, and
increased fertilization.
The data obtained by Johnson et al. (1965) suggest the im-
portance of fertilizer and cropping practices on the quality of agri-
TABLE 23.7. Absorption of ammonia volatilized from cattle feedlots.
Ammonia-N (kilograms per hectare)
Absorption*
Site Description Weekly Annual Precipitation
Control — no feedlots or
irrigated fields nearby ....
Small feedlots within 0.8 to
4 km
0.2 km east of 800-unit feedlot
and 0.6 km west of about
800-unit feedlot
0.5 km southwest of 9,000-unit
feedlot (shore of Clark Lake)
2 km northwest of 90,000-unit
feedlot (shore of Seeley
Lake)
2 km east of 90,000-unit
feedlot
0.4 km west of 90,000-unit
feedlot
0.15
0.34
0.57
0.62
1.3
1.3
2.8
3.9
9.1
15.0
17.0
34.0
34.0
73.0
0.22
0.29
0.32
0.29
0.53
0.40
0.61
Source: Hutchinson and Viets (1969).
* Absorption in 0.01 N FLSCX; absorption by lake water estimated to be one-
half of these.
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 323
TABLE 23.8. Estimated annual amounts of constituents in runoff from rural
land as affected by management practice (prevailing or im-
proved) and cover crop.
Pounds per Acre
of Constituent in Runoff for Cover Crop of
Corn
Wheat
Meadow
Constituent
Total solids
BOD
COD
Hydrolyzable P . . .
Total N
Pre-
vailing
33 200 0
120 0
1 300 0
9.2
237 0
Im-
proved
3 660 0
28 0
480 0
2.8
88 0
Pre-
vailing
1 730 0
160
170 0
1.2
31 0
Im-
proved
480 0
4 0
64 0
0.36
11 0
Pre-
vailing
Trace
Im-
proved
Trace
Source: Weidner et al. (1969).
cultural drainage (Table 23.9). The experiments were performed
on soils described as deep, permeable, silty clays, with tile drains
located at depths of 5.5 to 7 feet. More nitrogen was contained in
both tile drain effluents and surface runoff from fertilized than
from nonfertilized systems. However, phosphorus losses were low
compared to the phosphorus content of the irrigation water, suggest-
ing a net removal of phosphorus from the irrigation water by the
soil. Similarly, in the nonfertilized system, less nitrogen was lost
than applied in the irrigation water.
To evaluate the importance to eutrophication of agricultural
drainage relative to other nutrient sources, all nutrient sources for
the particular water must be considered. Estimates have been made
of the nutrient sources for Lake Mendota, Wisconsin, the surface
waters of Wisconsin, and the water supplies of the United States.
Review of these estimates is useful in evaluating the contribution
of agricultural drainage to the nitrogen and phosphorus status of
natural waters.
TABLE 23.9. Nitrogen and phosphorus balance for tile-drained soils under
different cropping and fertilizer treatments.
Pounds Applied
Pounds Lost
System
6
7
14
16
Nutrient
N
P
N
P
N
P
N
P
Fertilizer
22.216
4.025
14,112
2,328
0
0
3,864
0
Irrigation
1,263
373
347
54
1.317
165
1,357
156
Drainage
effluent
14.836
25
843
3
282
6
1,528
22
Surface
runoff
1.539
109
414
11
132
16
191
4
Applied
Nutrient
Lost
70
3
9
1
31
13
33
17
Source: Johnson et al. (19S5).
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324 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
Lake Mendota, Wisconsin
Lake Mendota, Wisconsin, provides an example of a lake in-
fluenced to a major degree by rural and urban areas. Because of
the importance of the lake to the region and concern over its eutroph-
ic nature, an attempt was made to estimate the amounts of nitrogen
and phosphorus entering the lake from various sources (Lee et al.,
1966; Schraufnagel et al., 1967).
Lake Mendota is approximately 9,730 acres in surface area,
with a maximum depth of 24 meters. Madison, with a population
of about 175,000, is the largest city in the watershed.
The Lake Mendota watershed covers about 142,000 acres and
is described by Schraufnagel et al. (1967) as an area occupied by
permeable, calcareous, loamy glacial deposits, with a significant
covering of loess. Most soil development is in the loess cover, with
some development occurring in the glacial till immediately below
the loess. Many of the soils were developed under prairie vegetation
and are characterized by an A horizon 8 to 16 inches thick and
relatively high in organic matter. Slopes in most of the watershed
are gentle. Numerous small, undrained depressions occur in the
uplands, and several large, wet lands containing organic soils are
located in the watershed. Numerous dairy farms occupy the area;
the estimated dairy cow population is 100 cows per square mile.
RURAL RUNOFF
The contribution of rural runoff to the nitrogen and phosphorus
budgets of Lake Mendota was estimated by considering the land
use in the watershed and the amounts of nutrients lost from each
type of land (Lee et al., 1966; Schraufnagel et al., 1967). The dis-
tribution of land in the watershed according to use is shown in
Table 23.10. A large portion (102,500 acres or 73%) of the water-
shed is devoted to cropland, with smaller areas in woodland (7% ),
pasture (8%), wetland (5%), and urban centers (7%).
Estimates of the amounts of nitrogen and phosphorus con-
tributed to Lake Mendota from the various types of rural lands are
shown in Table 23.11. The largest contribution was estimated to
TABLE 23.10. Estimated land use in the Lake Mendota watershed.
Land Use Acres Percent of Watershed
Cropland
Corn and row crops . . . .
Oats
Hay and pasture
Woodland
Pasture and other . . .
Major wetland
Urban
Total
103,500
51 000
18,500
34,000
10,000
11 400
7,100
10,000
142 000
73
36
13
24
7
8
5
7
100
Source: Water Subcommittee (1967).
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 325
TABLE 23.11. Estimates of the annual amounts of nitrogen and phosphorus
contained in runoff waters in the Lake Mendota watershed.
Pounds per Acre Pounds per Watershed
Land Use Nitrogen Phosphorus Nitrogen Phosphorus
Cropland and pasture . . .
Woodland
Wetland
Manured land
Total
0.06
0.03
3.0
0.04
0.003
1.0
6,900
300
45 000
52 200
5,400
30
15 000
20 430
Source: Water Subcommittee (1967).
be from manured land, accounting for about 87% of the nitrogen
and 73% of the phosphorus. Cropland contributed about 27% of
the phosphorus and 13% of the nitrogen. Although insufficient
data were available to estimate the contribution of wetlands, it
was believed that the amounts of nitrogen and phosphorus received,
particularly from drained marshes, would be significant.
The contributions from manured lands were calculated by
assuming that one-half of the manure from dairy cattle was ap-
plied to frozen soil and that 3 pounds of nitrogen and 1 pound of
phosphorus were lost for each 10 tons per acre application of
manure. These estimates were based on observation of Midgley and
Dunklee (1945) for a frozen soil of 8% slope. Amounts from crop-
land and pasture were estimated from concentrations in runoff
from.a Miami silt-loam soil with 10% slope (Eck et al., 1957) and
assuming 2 inches of runoff per year. Only water-soluble forms of
nitrogen and phosphorus were considered. Values for wooded areas
were obtained from the nitrogen and phosphorus contents of streams
flowing through these areas (Sylvester, 1960) and were considered
very rough estimates as they did not distinguish between amounts
contributed by surface runoff and base flow.
OTHER SOURCES
The relative importance of rural runoff, percolate waters, and
other sources is shown from the estimates of the total nutrient
budget of Lake Mendota recorded in Table 23.12 (Lee et al., 1966).
Rural runoff was the largest phosphorus contributor (42%), while
groundwater accounted for the major portion of nitrogen (52%).
However, the quantity of nitrogen contributed by rural runoff (52,-
000 Ib/yr) was larger than the corresponding quantity of phosphorus
(20,000 Ib/yr). For nitrogen, precipitation on the lake surface was
the second largest contributor (20% ), followed by rural runoff (11%)
and municipal and industrial wastewaters (10%). For phosphorus,
municipal and industrial wastewaters were the second largest
source (36%), followed by urban runoff (17%).
The large amount of soluble nitrogen contributed by ground-
water shows the importance of nitrate transport from soils to
-------
326 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
groundwater by water percolating through the soil. Estimates for
the contribution of groundwater included both that entering the
lake directly (about 30 cfs) and that reaching the lake through con-
tributing to the flow of surface tributaries (about 35 cfs). Concen-
trations of NO3-N of 2.5 mg/1 for groundwater entering through
surface tributaries and 1 mg/1 for direct-entering groundwater were
assumed. A lower NO3-N concentration for groundwater entering
below the surface was used because it was assumed that denitrifica-
tion was of greater importance in these waters than in surface
tributaries.
It is of interest to compare the estimates in Table 23.12 with
values obtained by measuring flow and nutrient concentrations in
the tributaries entering Lake Mendota (Rohlich, 1963). Tributary
measurements, which do not include groundwater entering the lake
beneath the surface, indicated that 259,700 pounds of inorganic
nitrogen and 343,400 pounds of total nitrogen entered the lake dur-
ing the year October 1948 to October 1949. This compares with a
total estimated nitrogen budget of 478,300 pounds per year in Table
23.12. The total phosphorus contribution from tributaries indicated
from direct measurements was 53,389 pounds per year compared
with an estimate of 47,000 pounds per year in Table 23.12.
Briefly, estimates of contributions from other sources shown
in Table 23.12 were obtained as follows: Quantities of nitrogen and
phosphorus in municipal and industrial wastewaters were estimated
from the individual sources, including municipal-treated domestic
wastes from small villages in the watershed, private domestic waste
disposal systems, milk and cheese processing and canning compa-
nies, and a car wash. Treated domestic wastes from the city of
Madison are not discharged into Lake Mendota. Urban runoff values
were estimated from data obtained for Cincinnati, Ohio (Weibel
et al., 1964), with allowances made for the higher degree of indus-
trialization of Cincinnati than of Madison. For precipitation, a value
of 10 pounds of nitrogen per acre per year was used (Shah, 1961);
the value of 1,300 pounds of phosphorus per year for Lake Mendota
TABLE 23.12. Estimated sources of nutrients for Lake Mendota, Wisconsin.
Percent of Total
Nutrient Source
Pounds per Year
Nitrogen Phosphorus Nitrogen Phosphorus
Municipal and industrial
waste water ....
Urban runoff
Rural runoff
Precipitation on lake
surface
Groundwater
Nitrogen fixation ....
Marsh drainage
Total
47,000*
30,300f
52,000f
97,000
250,000
2,000
478,300
17,000* 10
8,100f 6
20,000f 11
1.300 20
600 52
< 1
. Not estimated
47,000
36
17
42
3
2
Source: Nutrient Sources Subcommittee (1966).
* Total of nutrient forms.
f Soluble nutrient forms.
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 327
is an average value derived from several sources. The quantity of
nitrogen-fixation was based on a rate of 0.02% of nitrogen fixed per
day as reported by Goering (1963) and the assumption that nitrogen-
fixation occurs 3 months per year and in the top 3 meters of the
lake. Although marsh drainage was not estimated, its contribution
may be significant.
Nutrient Sources for Waters in Wisconsin
Using an approach similar to that described for the Lake Men-
dota watershed, the amounts of nitrogen and phosphorus reaching
surface waters of the state of Wisconsin from various sources were
estimated by Schraufnagel et al. (1967).
The importance of rural sources relative to other sources dif-
fered somewhat from the values for Lake Mendota (Table 23.13).
Rural sources were estimated to contribute 54% of the nitrogen.
Of this, the largest portion (42%) came from the groundwater.
Rural sources accounted for 30% of the phosphorus, 21.5% arising
from manured land runoff. However, municipal treatment facilities
were the largest phosphorus contributor (55.7%), while groundwater
contributed the largest portion of nitrogen, as was the case for Lake
Mendota.
Nutrient Sources for Water Supplies of the United States
In 1967 a Task Group of the American Water Works Association
prepared a report on the sources of nitrogen and phosphorus in
TABLE 23.13. Estimated amounts of nitrogen and phosphorus reaching Wis-
consin surface waters.
Thousands of
Pounds per Year Percent of Total
Source Nitrogen Phosphorus Nitrogen Phosphorus
Municipal treatment
facilities
Private sewage
systems
Industrial wastes
Rural sources
Manured lands . . .
Other cropland . . .
Forest land
Pasture, woodlot,
and other
Groundwater
Urban runoff
Precipitation on
water areas
Total .
20,000
4,800
1,500
8,110
576
435
540
34,300
4,450
6,950
81,661
7,000
280
100
2,700
384
44
360
285
1,250
155
12 558
24.5
5.9
1.8
9.9
0.7
0.5
0.7
42.0
5.5
8.5
100 0
55.7
2.2
0.8
21.5
3.1
0.3
2 9
2.3
10.0
1.2
100 0
Source: Water Subcommittee (1967).
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328 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
TABLE 23.14. Estimated amounts of nutrients contributed from various
sources for water supplies of the U.S.
Nutrient Source
Millions of
Pounds per Year
Nitrogen Phosphorus Nitrogen Phosphorus
Percent of Total'
Domestic waste ....
Industrial waste . . .
Rural runoff
Agricultural land
Nonagricultural
land
Farm animal waste •
Urban runoff
Rainfall
1,100-1,600 200-500
>1,000
1,500-15,000 120-1,200
400-1 900 150-750
>1,000
110-1 100 11-170
30-590 3-9
10
7
60
8
7
4
2
22.0
42.0
29 0
6.0
0.4
Source: AWWA Task Group 2610-P (1967).
* Percentages are based on mean value of ranges given.
water supplies in the United States (McCarty et al., 1967). Their
estimates are shown in Table 23.14. These estimates are for all
water supplies, including groundwater. Thus the contribution by
rural runoff includes drainage to the groundwater as well as surface
runoff. It should be noted that the percentages shown in Table 23.14
were calculated from the means of the ranges of values reported
by the Task Group and they may differ appreciably from the actual
average contribution for each source. Consequently the percentages
are useful only for very rough approximations. Futhermore, in the
manner calculated, the percentages total 100, even though farm ani-
mal waste and industrial waste contributions of phosphorus were not
estimated.
The values in this table suggest that agricultural land is an
important contributor of nitrogen and phosphorus to water. About
60% of the nitrogen and 42% of the phosphorus were estimated to
come from agricultural land. To arrive at these figures it was as-
sumed that the 308 million acres of cultivated land in the United
States contributed 5 to 50 pounds of nitrogen per acre per year or a
total of 1,500 to 15,000 million pounds of nitrogen per year. As
estimated, phosphorus contribution of 0.4 to 4 pounds per acre per
year gave the total estimated amount of 120 to 1,200 million pounds
per year.
It should be emphasized that the nutrient budget estimations
that have been discussed were based on data obtained on a small
scale in most cases, and extrapolation of these localized evaluations
to an entire watershed or larger area gives estimations of a rather low
reliability. More precise estimations based on more extensive evalua-
tion of representative watersheds would certainly be useful in plan-
ning management programs to control the influx of nitrogen and
phosphorus into water supplies. Nutrient sources are numerous and
generalizations as to which source is the most important cannot be
made. However, these estimations indicate that the contribution of
agriculture is significant. The challenge is that this contribution
should be reduced by improved and more efficient agricultural man-
agement practices.
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CHAPTER 23 / POLLUTION AND EUTROPHICATION / 329
REFERENCES
Armstrong, D. E., Spyridakis, D. E., and Lee, G. F. 1969. Cycling
of nitrogen and phosphorus in natural waters with particular
reference to the Great Lakes. Presented at the ACS Symp.
on the Chemistry of the Great Lakes, Minneapolis, Minn.
Biggar, J. W., and Corey, R. B. 1969. Agricultural drainage and
eutrophication. In Eutrophication: causes, consequences, cor-
rectives. Proc. Intern. Eutrophication Symp., Madison, Wis.
Wash., B.C.: Natl. Acad. Sci.
Duley, F. L., and Miller, M. F. 1923. Erosion and surface runoff
under different soil conditions. Mo. Agr. Exp. Sta. Res. Bull. 63.
Eck, P., Jackson, M. L., and Bay, C. E. 1957. Annual report AES
Project 791 (Phase 5).
Fruh, E. C., Stewart, K. M., Lee, G. F., and Rohlich, G. A. 1966.
Measurements of eutrophication and trends. J. Water Pollu-
tion Control Federation 38:1237-58.
Goering, J. J. 1963. Studies of nitrogen-fixation in natural fresh
waters. Ph.D. thesis, Zoology Dept., Univ. of Wis.
Hutchinson, G. L., and Viets, F. G., Jr. 1969. Nitrogen enrichment
of surface water by adsorption of ammonia volatilized from cat-
tle feedlots. Science 166:514-15.
Johnson, W. R., Illihadich, F., Daum, R. M., and Pillsbury, A. F.
1965. Nitrogen and phosphorus in tile drain effluent. Soil Sci.
Soc. Am. Proc. 29:287-89.
Lee, G. F., chairman, Nutrient Sources Subcommittee. 1967. Report
on the nutrient sources of Lake Mendota. Water Chemistry
Program, Univ. of Wis., Madison. (Mimeo.)
Lipman, J. G., and Conybeare, A. B. 1936. Preliminary note on the
inventory and balance sheet of plant nutrients in the United
States. N. J. Agr. Exp. Sta. Bull. 607.
Loehr, R. C. 1969. Animal wastes—a national problem. /. Sanit.
Eng. Div. Am. Soc. Civil Engrs. 95:189-221.
McCarty, P. L., chairman Task Group 2610-P. 1967. Sources of ni-
trogen and phosphorus in water supplies. /. Am. Water Works
Assoc. 59:344-66.
Midgley, A. R., and Dunklee, D. E. 1945. Fertility runoff losses from
manure spread during the ivinter. Univ. of Vt. and State Agr.
College Agr. Exp. Sta. Bull. 523.
Rawson, D. C. 1939. Some physical and chemical factors in the
metabolism of lakes. AAAS Bull. 10:9-26.
Rohlich, G. A. 1963. Origin and quantities of plant nutrients in
Lake Mendota. In Limnology in North America, ed. D. C. Frey.
Madison: Univ. of Wis. Press.
Sawyer, C. N. 1947. Fertilization of lakes by agricultural and urban
drainage. /. Neiv Engl. Water Works Assoc. 61:109-27.
Schraufnagel, F. H., chairman. Working Group on Control Tech-
niques and Research on Water Fertilization. 1967. Excessive
water fertilization. Report to Water Subcommittee, Nat. Re-
sources Committee of State Agencies, Wis. (Mimeo.)
Shah, K. S. 1961. Sulphus and nitrogen brought down in precipita-
tion in Wisconsin. Master's thesis, Soils Dept. Univ. of Wis.,
Madison.
Smith, G. E. 1964. Nitrate problems in plants and water supplies in
Missouri. 92nd Ann. Meeting, Am. Public Health Assoc., New
York City.
Stewart, B. A., Viets, F. G., Jr., Hutchinson, G. L., and Kemper,
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330 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
W. D. 1967. Nitrate and other water pollutants under fields
and feedlots. Environ. Sci. Technol. 1:736-39.
Stewart, K. M., and Rohlich, G. A. 1967. Eutrophication—a review.
Publ. 34, State Water Quality Control Bd., Calif.
Sylvester, R. O. 1960. Limnological aspects of recreational lakes.
Public Health Serv. Publ. 1167.
Sylvester, R. O., and Seabloom, R. W. 1962. A study on the char-
acter and significance of irrigation return flows in the Yakima
River Basin. A report from the Univ. of Wash.
Weibel, S. R., Anderson, R. J., and Woodward, R. L. 1964. Urban
land runoff as a factor in stream pollution. /. Water Pollution
Control Federation 36:914-24.
Weibel, S. R., Weidner, R. B., Cohen, J. M., and Christiansen, A. G.
1966. Pesticides and other contaminants in rainfall and runoff.
J. Am. Water Works Assoc. 58:1075-84.
Weidner, R. B., Christiansen, A. G., Weibel, S. R., and Robeck, G. G.
1969. Rural runoff as a factor in stream pollution. J. Water
Pollution Control Federation 41:377-84.
-------
CHAPTER TWENTY-FOUR
EFFECTS OF AGRICULTURAL
POLLUTANTS ON RECREATIONAL
USES OF SURFACE WATERS
ROBERT S. CAMPBELL and JAMES R. WHITLEY
^ECREATIONAL use of surface waters involves the employment
of leisure time for enjoyment of fishing, boating, swimming, and the
esthetic values of water. Pollution is the addition of material to
water which produces results undesirable to man, including death of
organisms, impairment of metabolic life processes, or the production
of nuisance odors and algal scums.
Man's full recreational enjoyment of water demands the presence
and diversity of animals and plants. The ecology of these living
organisms, and the impact of agricultural pollutants on them, is best
understood with reference to the aquatic community.
THE AQUATIC COMMUNITY
The aquatic community is the interdependent group of plants
and animals living in a lake, pond, or stream. Interdependence is
most easily seen in food-procuring activities, where each organism
functions as a food producer or as a consumer. This complex com-
munity is dependent on photosynthesis in the same way that all ag-
ricultural production is ultimately dependent on food synthesis by
green plants. The process of photosynthesis converts sunlight energy
to chemical energy which is incorporated into carbohydrates, fats,
and proteins. Thus, algae and rooted green plants are the producers
in the aquatic community and comprise the principal source of food
for the dependent group of consumer animals. In streams and rivers
rooted plants and algae are less abundant than in lakes. Plant ma-
terials produced on the land and washed into streams and lakes are
an additional food source for consumers.
Figure 24.1 shows that ingestion of green plants by animals
initiates the transfer of sunlight energy to one or more levels of
ROBERT S. CAMPBELL is Professor of Zoology, University of Missouri.
JAMES R. WHITLEY is Supervisor, Water Quality Investigations, Mis-
souri Department of Conservation.
331
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332 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
4th LEVEL CONSUMER TOP LEVEL CARNIVORE
(MUSKELLUNGE)
3rd LEVEL CONSUMER CARNIVOROUS FISH
(BASS)
2nd LEVEL CONSUMER PLANKTON FEEDING FISH
(MINNOW)
1st LEVEL CONSUMER ANIMAL PLANKTON
PRODUCER LEVEL ALGAE AND PLANTS
SUNLIGHT
FIG. 24.1. A simplified food chain involving one producer link and
four consumer links. Arrows indicate direction of flow of energy.
consumers, and demonstrates the dependence of each consumer level
on lower levels of consumers and ultimately on producers. At death
organisms are mineralized by decomposer bacteria and nutrients are
released to be incorporated by producers. Any factor which adversely
affects the environment of this complex community may affect
directly all levels (producer, consumer, decomposer) in the com-
munity. If only one level is directly affected, all other levels will be
affected indirectly because of their interdependence. Thus, environ-
mental pollution, however slight, may have far-reaching effects on
the entire aquatic community. For example, any agricultural prac-
tice which increases soil erosion and turbidity of water will interfere
directly with the photosynthetic process and indirectly with the
poundage of fish produced in that body of water.
We are concerned in this chapter with the aquatic communities
of streams and lakes. Agricultural pollutants that have a profound
impact on the aquatic community include (1) pesticides, (2) irriga-
tion return water, (3) eroded soil, and (4) agricultural fertilizers and
animal wastes.
PESTICIDES
Trace levels of pesticides in water may be concentrated in the
tissues of aquatic organisms. If these organisms are in turn eaten,
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CHAPTER 24 / POLLUTANTS AND RECREATIONAL USES / 333
pesticides are further concentrated in the consuming animals. Thus,
in one food chain, pesticides may become progressively concentrated
in animal tissues at successive levels, so in the third and fourth
consumer levels the concentration may exceed the concentration in
the water by several thousandfold. This phenomenon of biological
magnification occurs with the chlorinated hydrocarbon insecticides
because they are selectively absorbed into the oils, fats, and waxes in
the living organisms in the aquatic environment. Most surface waters
in the United States now contain DDT and its related compounds
(American Chemical Society, 1969). An example of this type of
pesticide magnification is the death of fish-eating birds resulting from
the use of DDD to control gnats in Clear Lake, California (Hunt and
Bischoff, I960; Rudd, 1964).
DDD was applied in 1949, 1954, and 1957, with near-complete
control of the gnat. Prior to 1949, more than 1,000 pairs of western
grebes nested at the lake but apparently did not breed subsequent to
treatment. Grebes did continue to visit the lake annually. There was
a die-off in 1954, 1955, and 1957, attributed to high levels of DDD in
the tissues. Inspection of the aquatic food chain showed that DDD
levels in tissues were progressively greater at successive consumer
levels (Table 24.1).
A prrblem closely related to biological magnification of chlori-
nated hydrocarbons is the development of resistance to pesticides by
organisms. The development of resistance is a well-known obstacle
in the control of insect pests with insecticides. Vinson et al. (1963)
reported resistance in fish to chlorinated hydrocarbons. The ability
of nontarget organisms to become resistant would seem to be
beneficial. However, resistance can be distastrous to fish popula-
TABLE 24.1. Biological magnification, Clear Lake aquatic food chain. Con-
centrations are maximal. Values for vertebrates are for vis-
ceral fat.
Food Chain
Level
Organism
Concen-
tration
of DDD
Concentration
of DDD
in Excess of
That in Water
Third-level
consumer
Second-level
consumer
First-level
fPredaceous birds
(grebes)
Carnivorous fish
(largemouth bass)
Plankton-feeding
small fish
Animal plankton
1,600.0
1,700.0
10.0
80,000 x
85,000 x
500 x
consumer
Producer level
Water
Plankton algae
j
5.3
0.02
265 x
Source: Modified from Rudd (1964).
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334 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
tions. Ferguson (1967) reports that some fish populations from
heavily treated areas can tolerate up to 1,500 times the dose of some
insecticides that is lethal to nonresident fishes. Ferguson states,
"Resistant fishes are able to tolerate massive body burdens of these
compounds in their tissues, and these residues constitute the source
of concern regarding the ecological significance of resistance," He
concludes, "Our findings indicate that although selection of a re
sistant fishery may permit exposed populations to survive, it may
ultimately produce a biological product dangerous to consumers of
all sorts, including man himself,"
A critical review of the literature on the effects of pesticides on
fishes (Johnson, 1968) emphasizes the following points: (1) Spraying
of streams has, in some instances, destroyed most of the aquatic in-
sects. (2) Pesticides do alter the composition of aquatic communities,
This can involve reduction in game fish, elimination of predators with
subsequent increase in prey species, arid reduction in members of the
zooplankton and bottom-dwelling invertebrates. (3) The degree of
toxicity may be dependent on the position of the plant or animal in
the food chain—the fourth level carnivore may be affected more than
the first-level consumer, due to biological concentration of pesticides.
(4) Most studies with fish have concerned acute toxicity where the
effect is measurable by death. When fish survived, the implication
was that the pesticide was not toxic at the level tested; the possibility
of damage through long-term exposure at sublethal concentrations
was not answered. (5) Acute toxicity is mainly injurious to the nerv-
ous system of fish. (6) There are reports of damage in fish to the
liver, gonads, blood, gills, and interference with normal physiological
processes.
A typical example of fish loss from exposure to DDT, anplied in
concentrations of 0.5 to 1 pound per acre, is cited from Cone and
Springer (1958): "Large numbers of dead trout, whitefish, and
suckers, including many young-of-the-year, were noted three months
after the spraying along a 100-mile stretch of the river. Great reduc-
tions in numbers of aquatic invertebrates again took ulace. This loss
of food appears to have been the chief cause of the fish die-off."
Burdick et al. (1964) compared fry survival from esgs gathered
from 12 lakes receiving varying amounts of DDT from the watershed.
The authors concluded that fry mortality was induced when con-
centrations of DDT in the egg exceeded approximately 3 prm. During
the st'Tdy period when the watershed of Lake George, New York, was
treated with amounts of DDT ranging from 0.30 to 0.57 pounds per
acre, concentration of the pesticide ranged from 4 to 15 ppm in egg
tissue and 112 to 515 ppm in egg oil.
In recent months coho salmon from Lake Michigan were re-
moved from the market by the Food and Drnp- Administration be-
cause they contained excessive residues of DDT. Some countries
and the states of Arizona and Michigan have banned the use of
DDT, and others are considering similar action.
The major concern of conservationists regarding chlorinated
hydrocarbon pesticides is the problem of persistence. The severe
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CHAPTER 24 / POLLUTANTS AND RECREATIONAL USES / 335
ecological effects resulting from pesticide levels which are hardly
measurable in the aquatic environment suggest that there is no safe
level of application of these persistent chemicals which is consistent
with economic agricultural use. These long-lasting compounds spread
worldwide throughout the environment and concentrate in dangerous
amounts through the food chain. There are alternatives to the use of
persistent pesticides in agriculture—namely, organic phosphates and
carbamates, and more intensive employment of biological controls.
IRRIGATION RETURN WATER
Irrigation was the greatest single use of water in the United
States in 1960, accounting for 135 out of a total use of 322 billion
gallons per day (U.S. Bureau of the Census, 1962). Water quality
changes resulting from irrigation include temperature increase and
total salinity increase. The more serious effects from temperature
elevation are reduction in the dissolved oxygen supply and increased
toxicity of polluting substances. An effect on fish of salinity increase,
caused by irrigation return water, was described for the San Joaquin
River, California, by Radtke and Turner (1967). Concentrations of
dissolved substances in excess of 350 ppm blocked the upstream
spawning migration of striped bass. However, at lesser concentra-
tions of 100 to 350 ppm, upstream migration occurred as indicated by
a 4- to 12-fold increase in gill-net catch.
ERODED SOIL
Photosynthesis in water is restricted to that upper euphotic zone
which receives 1% or more of incident sunlight. For example, the
euphotic zone in Lake Erie, 1939-40, varied in thickness from 32
feet when turbidity was 5 ppm to 3 feet when turbidity was 115 ppm
(Chandler, 1942). This reduction of light penetration by suspended
soil reduces total photosynthesis and hence total production within
the aquatic community. Chandler and Weeks (1945) proposed that
increased turbidity in 1942 in Lake Erie appeared to have resulted in
a 19% reduction of spring phytoplankton from the 1941 level. But-
ler (1964) wrote that primary productivity in central Oklahoma farm
ponds varied inversely with turbidity. Summer photosynthetic rate
in one clear pond was three times that of a turbid pond.
The effects of turbidity on fish and other consumer organisms
are varied, but the overall result is one of reduction in total produc-
tion. According to Trautman (1957), "Studies made since 1925 have
proved that since then, if not before, soil suspended in water has been
the universal pollutant in Ohio, and the one which has mast drastical-
ly affected the fish fauna. Clayey soils, suspended in water, prohibited
the proper penetration of light, thereby preventing development of
the aquatic vegetation, of the food of fishes, of fish egers and of fry."
These views are supported by Cordone and Kelley (1961): "There
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336 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
is abundant evidence that sediment is detrimental to aquatic life in
salmon and trout streams. The adult fishes themselves can apparent-
ly stand normal high concentrations without harm, but deposition of
sediments on the bottom will reduce the survival of eggs and alevins,
reduce aquatic insect fauna, and destroy needed shelter. There can
scarcely be any doubt that prolonged turbidity of any great degree is
also harmful."
Whether the physical contact of suspended solids is directly
detrimental to adult fishes is not resolved. Laboratory studies on 16
species of freshwater fishes suggested that "the direct effect of
montmorillonite clay turbidity is not a lethal condition in the life of
juvenile to adult fishes at turbidities found in nature" (Wallen, 1951).
Wallen reported that most individuals survived for a week or longer
exposures to 100,000 ppm suspended clay, a value at least lOx great-
er than expected turbidities in natural waters. On the other hand,
Herbert and Merkens (1961) concluded that continual abrasion by
suspended solids in concentrations of 90 to 810 ppm in experimental
tanks may have induced gill thickening which was observed in some
trout but not in others. They suggest that such gill alteration may
make fish more susceptible to other stresses in the environment and
thus reduce survival chances.
Effects of turbidity on bass and sunfish, measured over 2 grow-
ing seasons in 12 ponds in Illinois where turbidity was approximately
25 ppm in the clearer ponds and in excess of 100 ppm in the most
turbid, are described by Buck (1956): (1) The average total weight
of fish in the clear ponds was 5.5 times greater than in muddy ponds
at the end of the second growing season; (2) growth rate in length of
first-year bass was three times greater in the clear ponds than in
muddy ponds; (3) the weight increase in bass at the end of the
second growing season was 5.5 times greater in the clear ponds;
(4) bass reproduction was suppressed in the more turbid ponds. He
found similar results in studies on 14 hatchery ponds and 2 large
reservoirs. Swingle (1949) also reported the failure of largemouth
bass to spawn in ponds receiving a large inflow of highly turbid
water.
Aneler success for most game species is improved in clearer
water. "The clear reservoir attracted more anglers, yielded greater
returns per unit of fishing effort, as well as more desirable srjecies,
and was immeasurably more appealing in the aesthetic sense" (Buck,
1956). Catch success for game fish is directly related to water
clarity. In Little Dixie Lake, Missouri, in 1969, extended summer
rains restricted water visibility to a depth of 8 to 16 inches, June
through July. In August, water visibility increased to a depth of 37
inches. The catch of bass immediately increased 5-fold (J. L. Choate.
personal communication). Similarly, more bass and bluegill were
taken by anglers in Fork Lake, Illinois, during periods of increased
water transparency (Bennett et al., 1940). Angler use of the Meramec
River watershed (Missouri) dropped one-third when the water flow
was above normal and muddy, resulting in an estimated annual eco-
nomic loss of $60,775 to the residents (Brown, 1945).
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CHAPTER 24 / POLLUTANTS AND RECREATIONAL USES / 337
AGRICULTURAL FERTILIZERS AND ANIMAL WASTES
The slow process of aging of lakes and ponds is accompanied by
a gradual increase in nutrients with concomitant increased produc-
tion of animal and plant life. Associated with this is a reduction in
dissolved oxygen in deeper water because of accumulated organic
matter, and a loss in water transparency due to blooms of algae and
animal plankton. The term applied to aging is eutrophication and is
defined as the intentional or unintentional enrichment of water
(Hasler, 1947). Serious aspects of eutrophication include impairment
of esthetic qualities by unsightly nuisance algae and dense growth of
rooted plants and a hastening of lake extinction, since the accumu-
lated organic matter and eroded soils ultimately fill the lake basin.
Agricultural pollutants which hasten eutrophication include inor-
ganic fertilizers and animal wastes.
It is currently thought that nitrogen and phosphorus are the
elements most responsible for lake eutrophication (Mackenthun,
1968). Large quantities of nitrogen and phosphorus are contributed
to surface waters by agricultural drainage (Sawyer, 1947; Task
Group Report, 1967;'Mackenthun, 1968). It is shown (Table 24.2)
that concentrations in agricultural drainage and irrigation return
water are several times greater than in uncontaminated lakes and
streams, and as great or greater than in eutrophic lakes.
Concentrations of total phosphorus less than 0.01 ppm usually
limit biological activity, whereas nuisance algal blooms may be ex-
pected when total phosphorus exceeds 0.05 to 0.1 ppm. The relation-
ship of nitrogen and phosphorus enrichment to eutrophication is dis-
cussed by Armstrong and Rohlich (see Chapter 23).
It has been suggested that there is a relationship between weight
of the fish population and water fertility (Moyle, 1956; Table 24.2).
The relationship of the standing crop of fish in pounds per acre to to-
tal phosphorus in ppm was 40 toO.02, 90 to 0.034, 150 to 0.058. and
370 to 0.126. However, increase in standing crop is accompanied by
a change in species composition. For example, in Minnesota lakes
(Moyle, 1956), as the standing crop of fish increased from 40 to 370
pounds per acre, the structure of the fish population changed from
one involving lake trout in the 40 pounds per acre lakes to one in-
cluding yellow perch, walleye, northern pike, bass, and bluegill in
lakes cf intermediate poundage; and finally, in the 370 pound per
acre lakes, to one wrhere two-thirds of the standing crop were un-
desirable fish such as carp.
Marked biological changes associated with eutrophication in-
clude loss cf esthetic values associated with loss of water clarity and
development of algal blooms, and maior changes in fish fauna and
fish food organisms. Such changes have been described for Lake
Erie (Beetcn, 1965) and for lakes Zurichsee, Switzerland, and Men-
dota, Wisconsin (Hasler, 1947). More general aspects of biological
problems in recreational lakes are described by Mackenthun et al.
(1964). An annotated bibliography on nitrogen and phosphorus in
water was compiled by Mackenthun (1965).
-------
TABLE 24.2. Concentrations of nitrogen and phosphorus in milligrams per liter (ppm) in different aquatic communities, and
the relationship of nitrogen and phosphorus levels to biological activity.
Item
Soluble
Phosphorus
(as P)
Total
Phosphorus
(as P)
Inorganic
Nitrate
Nitrogen
(as N)
Total
Nitrogen
(as N)
Uncontaminated surface water ... ... 0.01-0.03 ... ...
Streams, forested area, little
habitation or land use 0.007 0.069 0.130 0.204
Eutrophic Green Lake, Seattle . . . 0.016 0.076 0.084 0.340
Sewage 1-13 3.5-9.0 7-40 18-50
Seepage water from agricultural
soils, Illinois 0.2-0.7
Surface irrigation return flow .... 0.162 0.251 1.250 1.455
Cattle feedlot wastes 16.3 ... 0.1-11
Limiting factor to biological
activity ... <0.01
Nuisance algal blooms expected
when values exceed 0.01 0.05-0.10 0.3
Fish production: 40 Ib/a ... 0.020
370 Ib/a ... 0.126
Ref.
Mackenthun (1968)
Sylvester (1961)
Sylvester (1961)
Bartsch (1961)
Task Group Report (1967)
Engelbrecht and Morgan (1961)
Sylvester (1981)
Miner et al. (1966)
Sawyer et al. (1945)
Sawyer (1947)
Mackenthun (1968)
Moyle (1956)
Moyle (1956)
Note: The values of N and P in relationship to animal and plant production should be considered only as indicative of
general relations since there is much variation among lakes and many factors affect production.
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CHAPTER 24 / POLLUTANTS AND RECREATIONAL USES / 339
TABLE 24.3. Wastes of hogs and cattle in Missouri expressed as human
population equivalents.
Population
Man
Hogs and pigs
Cattle and calves . . . .
Number in
Missouri,
1959*
. . . 4,320 000
. . . 4,257 000
. . . 4,748,000
Individual
Pounds BOD
per Day
0 17
0.41
1.20
Approximate
Population
Equivalent
4 320 000
10,260,000
33,520,000
Source: Modified from Ray (1965).
* USDA Statistical Reporting Service.
Animal wastes which enter surface waters have such a high
oxygen demand that they rapidly exhaust the dissolved oxygen. Ray
(1965) expressed animal waste in terms of "human population
equivalents" by dividing the oxygen requirements (pounds BOD per
day) of animal waste by 0.17, the value for human wastes. The pop-
ulation equivalents calculated for hogs and cattle on farms in Mis-
souri, 1969, are shown in Table 24.3. Clearly the organic load of
animal wastes represents a potential oxygen demand on receiving
waters in excess of that imposed by human waste. The concentra-
tion of animals in feedlots with uncontrolled drainage results in
exaggerated surface water degradation at the locations of those
drainages. Dissolved oxygen concentration should be above 5 ppm
for a diversified warm-water fauna (Federal Water Pollution Control
Administration, 1968). Lower concentrations adversely affect the
respiratory rate and general metabolism; prolonged concentrations
as low as 2 ppm are often fatal to fish.
Cross and Brasch (1969) described a change in land use pattern
in the Neosho River watershed, Kansas, from seasonal grazing to
year-round maintenance of cattle, with many concentrated in feed-
lots. Associated with this change was a loss of 5 species of fishes
and a decline in abundance of at least 20 species. Numerous fish
kills were attributed to pollution from cattle feedlots whose wastes
drained into streams.
Smith and Miner (1964) considered animal feedlot runoff a
significant source of water pollution in Kansas. They described run-
off water quality as follows: (1) very high organic content, (2) con-
centrations of ammonia frequently in excess of 10 ppm, and (3)
heavy bacterial populations. The existence of pollution was usually
indicated by fish kills which they attributed to ammonia and lo\v
dissolved oxygen.
PUBLIC LAWS
With the recent adoption of wrater quality standards by the
states, minimal limits for the addition of agricultural pollutants to
state waters were set by state law and are backed by federal enforce-
ment.
The Federal Water Pollution Control Act of 1948 (Public Law
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340 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
660) formed the basis for federal-state cooperation and for enforce-
ment of federal regulations on interstate waters through the attorney
general. With the adoption of the Federal Water Quality Act of 1965
(Public Law 234) Congress authorized the states and the federal
government to establish water quality standards for interstate waters.
After holding public hearings the states adopted standards and sub-
mitted them for review by the secretary of the interior. As of May
1969, there was whole or partial acceptance of water quality stand-
ards by all 50 states.
The development of standards considers the uses to be made of
the water in question, the assignment of specific water quality criteria
to protect the water use, and plans for implementation and enforce-
ment. Water quality criteria differ from state to state and for dif-
ferent waters within a state.
A standard reference for water quality criteria which will pro-
tect recreational and other uses of surface water is the Report of the
National Technical Advisory Committee to the Secretary of the In-
terior (Federal Water Pollution Control Administration, 1968).
Criteria adopted by the state of Missouri are cited as examples of
their application to agricultural pollutants:
All tributary streams and all municipal, industrial, agricultural,
and mining effluents shall not create conditions in the stream which
will adversely affect the present water uses or ths future water uses
as they become current.
Pesticides. Substances toxic to man, fish, and wildlife or detri-
mental to agricultural, mining, industrial, recreational, navigational,
or other legitimate uses shall be limited to nontoxic or nondetrimental
concentrations in the streams.
Irrigation Return Water. Effluents shall not elevate or depress
the average cross-sectional temperature of the stream more than 5°F.
The stream temperature shall not exceed 90°F due to effluents.
Eroded Soil. There shall be no turbidity of other than natural
origin that will cause substantial visible contrast with the natural
appearance of the stream or with its legitimate uses. There shall be
no noticeable man-made deposits of solids either organic or inorganic
in nature on the stream bed.
Animal Wastes. Dissolved oxygen in the stream shall not be less
than 5 ppm at any time due to effluents or surface runoff.
The intent of enforcement of water quality standards (and the
specific water quality criteria) is the orderly development and improve-
ment of the nation's water resources, guaranteeing their long-time
preservation for industrial, municipal, and agricultural uses, for recre-
ation, and for esthetic enjoyment.
CONCLUDING STATEMENT
Unquestionably many agricultural pollutants affect recreation
through alteration of water quality and degradation of fish and
aquatic life. The more serious polluting agents we judge to be eroded
soil, nutrients, and pesticides. We sense there is an awareness and
appreciation of the problem among those concerned with agriculture.
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CHAPTER 24 / POLLUTANTS AND RECREATIONAL USES / 341
While the problems relating to agricultural pollution are complex,
and the solutions will not easily be attained, it seems reasonable that
in many instances alternative procedures can be developed. Pollu-
tion control measures are available (e.g., pesticides) which will allow
continuation of agricultural production and enhance and protect
water quality and recreation. While these procedures may be costly to
apply, the expenditure should be judged in light of its contribution
toward the preservation of man's environment. Especially in the
instance of pesticide use, protection of water quality may be requisite
to protection of the health of man from unknown long-term effects of
pesticides. Reduction and control of agricultural pollutants are es-
sential to develop and maintain a high-quality environment. Quality
of life and quality of environment are synonymous.
REFERENCES
American Chemical Society. 1969. Cleaning our environment: the
chemical basis for action. Am. Chem. Soc.. Wash., B.C.
Bartsch, A. F. 1961. Induced eutrophication—a growing water re-
source problem. In Algae and metropolitan wastes, pp. 6-9. U.S.
Dept. of Health, Education and Welfare.
Beeton, A. M. 1965. Eutrophication of the St. Lawrence Great Lakes.
Limnol. Oceanog. 10:240-54.
Bennett, C. W., Thompson. D. H., and Parr, S. A. 1940. A second
year of fisheries investigations at Fork Lake, 1939. Lake Man-
agement Kept. 4. III. Nat. Hist. Sari;., Biol. Notes 14:1-24.
Brown, C. B. 1945. Floods and fishing. Land 4:78-79.
Buck, D. H. 1956. Effects of turbidity on fish and fishing. Trans.
21st North Am. Wildlife Conf., pp. 249-60.
Burdick, G. E., Harris, E. J., Dean, H. J., Walker. T. M., Skea, J., and
Colby, D. 1964. The accumulation of DDT in lake trout and
the effect on reproduction. Trans. Am. Fisheries Soc. 93:127—
36.
Butler, J. L. 1964. Interaction of effects by environmental factors
on primary productivity in ponds and microecosystems Ph.D.
thesis, Okl'a. State Univ. Graduate School.
Chandler, D. C. 1942. Limnological studies of western Lake Erie.
II. Light penetration and its relation to turbidity. Ecology
23:41-52.
Chandler, D. C., and Weeks, O. B. 1945. Limnological studies of
western Lake Erie. V. Relation of limnological and meteor-
ological conditions to the production of phytoplankton in 1942.
Eco/. Monographs 15:435—57.
Cope. O. B., and Springer, P. F. 1958. Mass control of insects: the
effects on fish and wildlife. Bull. Entomol. Soc. Am. 4:52-56.
Cordone, A. J., and Kelley, D. W. 1961. The influences of inorganic
sediment on the aquatic life of streams. Calif. Fish Game
47:189-228.
Cross, F. B., and Braasch, M. 1969. Qualitative changes in the fish-
fauna of the upper Neosho River system, 1952-1967. Trans.
Kans. Acad. Sci. 71:350-60.
Engelbrecht, R. S., and Morgan, J. J. 1961. Land drainage as a
source of phosphorus in Illinois surface waters. In Algae and
-------
342 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
metropolitan wastes, pp. 74-79. U.S. Dept. of Health, Educa-
tion and Welfare.
Federal Water Pollution Control Administration. 1968. Water qual-
ity criteria. Report of the Nat. Tech. Advisory Committee to the
Sec. of the Interior.
Ferguson, D. E. 1967. The ecological consequences of pesticide
resistance in fishes. Trans. 32nd North Am. Wildlife Nat. Re-
sources Conf., pp. 103-7.
Ferguson, D. E., Culley, D. D., Cotton, W. D., and Dodds, R. P. 1964.
Resistance to chlorinated hydrocarbon insecticides in three
species of freshwater fish. BioScience 14:43-44.
Hasler, A. D. 1947. Eutrophication of lakes by domestic sewage.
Ecology 28:383-95.
Herbert, D. W. M., and Merkens, J. C. 1961. The effect of suspended
mineral solids on the survival of trout. Intern. J. Air Water
Pollution 5:46-55.
Hunt, E. G., and Bischoff, A. I. 1960. Inimical effects on wildlife
of periodic DDD applications to Clear Lake. Calif. Fish Game
46:91-106.
Jamison, V. C., Smith, D. D., and Thornton, J. F. 1968. Soil and
water research on a clay pan soil. USDA, ARS Tech. Bull. 1379.
Johnson, D. W. 1968. Pesticides and fishes—a review of selected
literature. Trans. Am. Fisheries Soc. 97:398-424.
McKee, J. E., and Wolf, H. W. 1963. Water quality criteria. 2nd ed.
Calif. State Water Quality Control Bd. Publ. 3-A.
Mackenthun, K. M. 1965. Nitrogen and phosphorus in water. An
annotated selected bibliography of their biological effects. Pub-
lic Health Serv. Publ. 1305.
. 1968. The phosphorus problem. /. Am. Water Works Assoc.
60:1047-54.
Mackenthun, K. M., Ingram, W. M., and Forges, R. 1964. Limno-
logical aspects of recreational lakes. Public Health Serv. Publ.
1167.
Miner, J. R., Lipper, R. I., Fina, L. R., and Funk, J. W. 1966. Cattle
feedlot runoff—its nature and variation. /. Water Pollution
Control Federation 38:1582-91.
Moyle, J. B. 1956. Relationships between the chemistry of Minne-
sota surface waters and wildlife management. /. Wildlife Man-
agement 20:303-20.
Piest, R. F., and Spomer, R. G. 1968. Sheet and gully erosion in the
Missouri Valley loessal region. Trans. Am. Soc. Agr. Engrs.
11:850-53.
Radtke, L. D., and Turner, J. L. 1967. High concentration of total
dissolved solids block spawning migration of striped bass,
Roccus saxatilis, in the San Joaquin River, California. Trans.
Am. Fisheries Soc. 96:405-7.
Ray, A. D. 1965. Pollution from industrial wastes and sewage. In
Water Forum, pp. 31-36. Spec. Rept. 55, College of Agr., Univ.
of Mo., Columbia.
Rudd, R. L. 1964. Pesticides and the living landscape. Madison:
Univ. of Wis. Press.
Sawyer, C. N. 1947. Fertilization of lakes by agricultural and urban
drainage. /. New Engl. Water Works Assoc. 6.1:109-27.
Sawyer, C. N., Lackey, J. B., and Lenz, R. T. 1945. An investigation
of the odor nuisances occurring in the Madison lakes, particu-
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CHAPTER 24 / POLLUTANTS AND RECREATIONAL USES / 343
larly Monona, Waubesca and Kegonsa from July 1942 to July
1944. Kept, of the Governor's Committee, Madison, Wis.
Smith, S. M., and Miner, J. R. 1964. Stream pollution from feedlot
runoff. Trans. 14th Ann. Conf. Sanit. Eng. Univ. of Kans.
Publ., Bull, of Eng. and Architecture 52:18-25.
Swingle, H. S. 1949. Some recent developments in pond manage-
ment. Trans. 14th North Am. Wildlife Conf., pp. 295-310.
Sylvester, R. O. 1961. Nutrient content of drainage water from
forested, urban and agricultural areas. In Algae and metropoli-
tan ivastes, pp. 80-87. U.S. Dept. of Health, Education and
Welfare.
Task Group Report. 1967. Sources of nitrogen and phosphorus in
water supplies. /. Am. Water Works Assoc. 59:344-66.
Trautman, M. B. 1957. The fishes of Ohio. Columbus: Ohio State
Univ. Press.
U.S. Bureau of the Census. 1962. Statistical abstract of the United
States.
Vinson, S. B., Boyd, C. E., and Ferguson, D. E. 1963. Resistance to
DDT in the mosquito fish, Gambusia affinis. Science 139:
217-18.
Wallen, I. E. 1951. The direct effect of turbidity on fishes. Bull.
Okla. Agr. Mech. College 48:1-27.
The White House. 1965. Restoring the quality of our environment.
Rept. of the Environ. Pollution Panel, President's Sci. Advis.
Committee.
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CHAPTER TWENTY-FIVE^
EFFECTS OF SURFACE RUNOFF
ON THE FEASIBILITY OF
MUNICIPAL ADVANCED WASTE TREATMENT
E. ROBERT BAUMANN and SHELDON KELMAN
• HE state of Iowa has been a national leader in water pollu-
tion control for nearly half a century. Its first stream control law,
passed in 1923, gave the State Department of Health regulatory and
enforcement authority. At the time the 1923 law was passed, almost
200 municipal sewage treatment plants were already in operation
(Iowa Water Pollution Control Commission, 1969). These plants
were in the smaller towns and served 350,000 persons, or 30% of
the population connected to municipal sewers.
The pollution control law has been revised twice, the latest re-
vision being enacted in 1965. This legislation created the Iowa Water
Pollution Control Commission as the policy-making body in Iowa's
water pollution activities. Present stream water quality regulations,
in effect, necessitate secondary treatment (85 to 90% removal of
BOD) on all interior streams.1 Plant construction has steadily pro-
gressed so that as of January 1, 1969, there were 510 municipal
water pollution control plants in operation or under construction, and
the population served by treatment had increased to 99.3% of the
sewered population. Municipalities not presently treating their wastes
are smaller communities which now have plants in the planning or
construction stage. One hundred percent of the medium size and
larger communities had sewage treatment facilities at the beginning
of 1969. This record of water pollution control ranks Iowa with the
most progressive states in the nation.
Of the industries, Iowa's meat-packing plants represent the
largest potential source of industrial water pollution. Every meat-
packing plant in the state has a treatment plant in operation or under
construction (Iowa Water Pollution Control Commission, 1969), and
this represents some 3.5 million population equivalent being treated.
E. ROBERT BAUMANN is Professor, Department of Civil Engineering,
Iowa State University. SHELDON KELMAN is Assistant Professor, De-
partment of Civil Engineering, Iowa State University.
1. In October 1969, the FWPCA adopted national regulations requir-
ing Iowa to provide secondary treatment also for all wastes discharg-
ing to both the Mississippi and Missouri rivers.
344
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CHAPTER 25 / ADVANCED WASTE TREATMENT FEASIBILITY /
With the exception of packing plants on border streams, all packing-
plant wastes receive at least secondary treatment.
Although this municipal and industrial waste treatment record
is impressive, much work remains before the quality of the water in
our streams is adequately protected. Some cities have grown to the
point where their treatment facilities are undersized and/or obsolete.
Most secondary treatment facilities do not provide sufficient treat-
ment efficiency in the wintertime (only 65 to 75% removal of BOD)
due to the effects of cold weather on the efficiency of biological treat-
ment on trickling filters. Recently, some authorities have been call-
ing for still higher levels of wastewater treatment to alleviate water
pollution problems. Iowa's interior streams are characterized in
much of the state by extremely low minimum flows and relatively
high summer temperatures. At Ames, for example, the design flow
in the Skunk River (7-day low flow with a frequency of occurrence
of once in 10 years) is only 0.1 cfs while the Ames waste discharge
currently approximates 5.0 to 6.0 cfs. Even when low flow augmen-
tation is available from the proposed Ames reservoir, the design
stream flow will be increased to only 30 to 40 cfs. Under these con-
ditions—typical of those for many of Iowa's cities and industries—
maintenance of current water quality standards in Iowa streams
will require better waste treatment. The treatment needs indicated
include:
i. increased carbonaceous BOD removal
"2. increased oxidation of the ammonia in the treated waste to ni-
trate
3. increased phosphate removal
The increased removal of carbonaceous BOD is required to maintain
the oxygen level in the stream to protect fish life. The oxidation of
ammonia to nitrate is required to reduce the ammonia levels in the
stream below levels toxic to fish. Unfortunately, the increased oxida-
tion of ammonia to nitrate, together with the availability of -phos-
phates in the stream, results in significant algal growths. Such algal
growths can have a detrimental effect on water quality because:
1. they increase the carbonaceous BOD in the stream and may re-
sult in significantly lowered DO levels at night
2. they increase the turbidity and suspended solids load in the
stream and can impart tastes and odor to the water
Before increased treatment requirements (advanced waste or tertiary
treatments) are imposed on cities and industries, it would appear de-
sirable to consider first whether such wastes are the more significant
contributors of carbonaceous BOD, nitrates, and phosphates to Iowa
streams. Agriculture which contributes carbonaceous BOD from
animal wastes, plant residues, etc., and phosphates and nitrates from
the above sources and from fertilizer applications may contribute
such significant quantities of similar pollutants on an uncontrolled
area basis as to negate any desirable effect of increased municipal
and/or industrial waste treatment.
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346 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
This chapter is designed to explore the relative effects of both
municipal-industrial and agricultural wastes as they affect treatment
requirements which may be imposed on municipal use of the stream
for receiving treated wastes.
MUNICIPAL-INDUSTRIAL WASTE TREATMENT
Each treatment process achieves certain end results. For many
years all Iowa municipal and industrial wastes have received primary
treatment. Primary treatment is commonly a settling process which
removes floating and settleable material, including a portion of the
suspended solids and its associated organic carbon. The organic
carbon is measured by the amount of oxygen bacteria required to
oxidise it in a fixed time period under aerobic conditions. Thus the
organic carbon removal is typically described as a reduction in bio-
chemical oxygen demand or reduction in BOD.- (measured in 5 days
at 20° C). Primary treatment will remove over 95% of the floating
and settleable solids, from 60 to 70% of suspended solids, and from
30 to 40% of BOD5. Since much of the organic carbon is present in
solution or in colloidal suspension, most (60 to 70%) is not remova-
ble by sedimentation.
All Iowa municipal-industrial wastes will ultimately require
secondary treatment prior to discharge to Iowa's surface waters.
Secondary treatment normally employs a biological process utilizing
bacteria and other simple forms of life to convert much of the re-
maining suspended and soluble organic carbon to biological cell
protoplasm and energy. These process units are then followed by
sedimentation tanks to remove the cells produced. Typical domestic
effluents after secondary treatment contain only 10 to 20% of their
original suspended solids and BOD and involve pollutant removal
efficiencies of 80 to 90% under ideal conditions.
Primary and secondary treatments (complete treatment) remove
only part of the wastes in wastewater. The organic material present
is partially oxidized and partially converted into settleable cell pro-
toplasm. This reaction can be represented empirically as2
bacteria
COHNSP + O. > protoplasm + CO2 + H=O + NCV + NOr
+ NH.,+ + SOr' + POr" + organic P
Thus, it can be seen that although secondary treatment removes 80
to 90% of the organic carbon and reduces the oxygen demand on
the stream which receives the treated wastes, these wastes will con-
tain significant amounts of NO2, NO3, and NH3 as well as phospho-
rous compounds, substances that are also applied to land in the form
of common fertilizers. These compounds have become increasingly im-
portant since in recent years the widespread use of phosphate builders
in detergents has more than doubled the concentration of phosphorus
2. Note: C = carbon; O = oxygen; H = hydrogen; N= nitrogen;
S = sulfur; P = phosphorus.
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CHAPTER 25 / ADVANCED WASTE TREATMENT FEASIBILITY / 347
in municipal wastewaters. In addition, significant concentrations of
nonbiologically degradable organics will remain in the wastevvater.
Nitrogen and phosphorus in municipal and industrial wastewa-
ters add to the concentrations of these fertilizer elements in surface
waters. Such nutrient enrichment of water is termed eutrophication
and is of concern since it stimulates algal growth. This process can
be represented as
Algae
POr" + NO3- + CO, + sunlight > COHNSP (Algae protoplasm)
Algae thus defeat the purpose of secondary treatment by creating
more organic carbon (which we have just removed by primary and
secondary treatment) in surface waters.
In the past 10 years attention has been focused on the problems
created by such eutrophication. Many studies have been made of
the various methods intended to solve this problem by achieving a
higher degree of wastewater treatment. These methods employ an
additional treatment step, usually termed tertiary treatment. Ter-
tiary treatment is designed to achieve either a better degree of sus-
perded solids and BOD removal and/or the removal of nonbiologi-
cally degradable organic and inorganic compounds, especially nitro-
gen and phosphorous compounds. Tertiary treatment, now economi-
cally and technically feasible, can result in BOD and phosphate re-
movals of above 98% and the effluent quality would be as good or
better than that of the receiving stream.
Among the processes which can be used singly or in combination
to achieve these results are
\. lime or alum precipitation of phosphates
2. air stripping of ammonia at high pH levels
3. activated carbon adsorption of dissolved organics
4. pulsed adsorption beds (PAB) for increased biological removal of
dissolved organics
5. sand or diatomaceous earth filtration for removal of residual bi-
ological cells and suspended organics
6. ion exchange for removal of specific cations and anions
All of these processes are expensive relative to present treatment
methods. To put such a program into effect on a statewide basis for
all municipal and industrial wastewater will cost many millions of
dollars. Adding typical tertiary processes, such as lime precipitation
for phosphorus removal and air stripping of ammonia, could triple
the cost of wastewater treatment for a typical Iowa city.
EFFECTS OF NUTRIENTS IN SURFACE WATERS
To understand why there is a concern over the addition of ni-
trates and phosphates to surface water, it is first necessary to consider
its effect on water uses. The presence of pyrophosphates and/or tri-
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348 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
phosphates has been shown to interfere with the efficiency of potable
water treatment processes, including the coagulation-flocculation-
sedimentation process and the lime-softening process. These prob-
lems become noticeable (Task Group Report, 1966) at combined
triphosphate and pyrophosphate levels of 0.3 mg/1, measured as P.
Shrobe (1967) found that approximately half the phosphates dis-
charged in treated wastewater are orthophosphates and this ratio
continues several miles downstream from the treatment plant. Most
of the remaining phosphate will be in the condensed forms discussed
above. Since typical Iowa rivers have been found to contain peak
orthophosphate levels approaching 3 mg/1 (Dept. of Civil Engineer-
ing, Engineering Research Institute, 1969), it can be assumed that
similar levels of condensed phosphates will also be present below
sewage discharges, creating potable water treatment difficulties.
Two of the principal nitrogen compounds, nitrates and am-
monia, also cause problems. The United States Public Health Service
drinking water standards limit the concentration of nitrates in po-
table water to 45 mg/1 as nitrate. This limit is based on the fact that
higher levels cause methemoglobinemia in infants. In general, ni-
trate levels in surface waters are well below this limit; however,
there are times when Iowa rivers contain more than 45 mg/1 nitrates
(Engineering Research Institute, 1969). Ammonia causes problems
by increasing significantly the chlorine demand of water if an un-
combined or "free" chlorine residual is required. Ammonia is also
detrimental to stream water quality since it is toxic to fish. The Iowa
water quality standards for fishing streams limit the allowable am-
monia concentration to 2 mg/1.
The major water quality problem created by nitrogen and phos-
phorus, however, is concerned with their stimulation of algae growth.
Algae create problems in potable water treatment by clogging filters
and causing undesirable tastes and odors. These problems were esti-
mated in 1967 to affect as much as 56# of total municipal surface
water supplies in the United States (Task Group Report, 1966).
Algae interfere with recreational use of rivers and lakes by col-
oring the water green and forming unsightly floating mats. Fish may
be affected when large numbers of algae are present by lowering sig-
nificantly the DO during the night. This algae oxygen demand can
deplete the dissolved oxygen sufficiently to lead to fish kills. Fish
may also find it hard to feed if the algae color the water and obscure
their vision.
The conservationist pressures to solve the problems created by
eutrophication are becoming greater every year. However, before we
move toward requiring tertiary treatment of municipal and industrial
wastes to control nutrient discharges in agricultural regions, we need
to determine whether even 100% tertiary treatment of these waste-
waters will correct the problems of eutrophication or even contribute
to the correction. To accomplish this, we need to determine the rel-
ative nutrient contributions from various sources.
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CHAPTER 25 / ADVANCED WASTE TREATMENT FEASIBILITY / 349
SOURCES OF NUTRIENTS
Several potential sources of nitrogen and phosphorus which can
enter the surface waters of Iowa are readily recognized. For years,
industrial and municipal wastes have been pointed out as the major
contributors of N and P. In recent years, attention has been focused
on the potential contribution from surface runoff. Corey et al. (1967)
have listed the following available nitrogen sources for plant growth:
soil organic matter, animal manure, legume fixation, commercial
fertilizer, and fertilizer naturally present in precipitation. The same
sources, of course, are potential contributors of nitrogen to runoff.
The average daily N and P contribution of each person connected
to a sewer is well established. Given sewered population data, the
quantities of nitrogen and phosphorus discharged in domestic waste-
water can readily be computed (an example will be discussed later
in this chapter). Other sources of these nutrients may equal or even
exceed the quantities in domestic wastewater. Industrial wastes, es-
pecially those from packinghouses, contain large quantities of nitro-
gen and phosphorus, since meat is a protein containing high con-
centrations of both N and P.
Animal wastes form an increasing source of such nutrients.
Both wild and domestic animals are significant sources of fertilizer
elements. When storm runoff occurs, large quantities of animal
wastes are washed into streams. In Iowa, for example, we have a
domestic population of 2.75 million. This state is noted, however, for
its production of pork and beef. Approximately 6,100,000 swine and
3,300,000 beef animals are on feed at any one time. Nearly 46,000
cattle feedlots are recorded in Iowa. The daily waste from these
animals is equivalent to the dailv waste from a human population of
65 to 90 million people. Naturally, not all this waste finds its way
into our streams. But when it rains—as it does in Iowa 20 to 30
times per year with intensities of 1 inch/hour or more—several days'
accumulation of these wastes may find their way into our surface
waters. Feedlot regulations are now designed to control runoff from
feedlots that feed over 100 head of cattle. Such animal wastes, to-
gether with dairy and poultry wastes, can be significant contributors
of carbonaceous and nitrogenous BOD. ammonia, and nitrogen to
our surface waters.
Another increasing source of the nutrients which enhance
eutrophication is that derived from row crop agriculture. Nitrogen
fertilizer use in the United States has increased from 2.15 million
tons in 1957 to 6.56 million tons in 1968 (Sulphur Institute. 1969).
The 1957 figure represents 76 rc of total United States consumption
of nitrogen at that time (Sauchelli, 1961). During approximately the
same time period, phosphorus use in fertilizers has risen from 0.99
million tons in 1958 (Van Wazer. 1961) to 2 02 million tons P in
1968 (Sulphur Institute, 1969). The 1958 figure represents 70% of
that year's total United States consumption of phosphorus. Other
large uses of phosphorus include use in detergents (13.3%) and in
animal feeds (8.4%). Reportedly, commercial fertilizers are the
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350 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
source of only 10 to 20% of the gross nitrogen available for agricul-
ture (Corey et al., 1967; Willrich, 1969).
The United States as a whole is in a nutrient mining phase; i.e.,
more nutrients are removed in the harvested crops than are replaced
by all nutrient inputs, including commercial fertilizers. This is us-
ually true for most Iowa crops. Corn can be an exception, however.
High rates of nitrogen application in excess of 150 to 200 pounds per
acre may cause a nitrogen accumulation situation rather than a min-
ing situation depending on the amount of corn grain and stalks that
are harvested. If only the grain is harvested, about 1 to 1.2 pounds
of nitrogen are required per bushel of corn. If the whole plant is
harvested for silage, about 2 pounds of nitrogen are removed for
each bushel of corn produced.
TVA statistics (National Fertilizer Development Center, 1968)
indicate that the average 1968 Iowa application rate of nitrogen on
corn was 120 pounds N per acre. The USDA Statistical Reporting
Service stated the average Iowa corn yield for 1968 was 93 bushels
per acre.
WATER QUALITY IN DES MOINES RIVER-BOONE TO DES MOINES
For the past 2 years, the Sanitary Engineering Section of the
Engineering Research Institute at Iowa State University has been
making surface water quality studies between Boone and Des Moines
as a part of a "Preimpoundment Survey of Water Quality in the Des
Moines River above Saylorville Reservoir." This study is supported
by the Rock Island District, Corps of Engineers. Among the param-
eters measured weekly are stream flow, BOD, COD, suspended solids,
turbidity, the various forms of nitrogen, phosphates, and the algal
count.
Total algal counts have been extremely high as shown by the
algal count data for 1968. For example, in the first 6 months of 1968,
the phytoplankton count averaged 96,000 cells/ml, ranging from
17,000 to 281,000 cells/ml. These values appear to be 5 to 10
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CHAPTER 25 / ADVANCED WASTE TREATMENT FEASIBILITY / 351
must be made of the nonsewered rural population, most of which use
septic tanks. At the present time, roughly half the Iowa population
of 2,783,000 can be classified as being rural (Iowa Natural Resources
Council, 1953). Part of the wastes from this population eventually
reaches a stream by surface runoff or by illegal connections to drain
tiles, or enters the groundwater and reaches a stream during low flow
periods. Since the rural population is rather evenly distributed
throughout the state, the ratio of the basin's rural population to the
state's rural population should be roughly equal to the ratio of the
two areas. The estimated rural population calculated on this basis is
135,600. Some of the nutrients in the rural wastes are removed by
plant uptake or lost by denitrification, soil adsorption, etc., and we
can assume that only 50% reaches a stream. The effective total
population contributing wastewater to the Des Moines River is thus
171,500. An average value for nitrogen in wastewater is about 10
pounds per capita per year (Task Group Report, 1967). At this rate
we could expect roughly 4,700 pounds nitrogen per day or 860 tons
of nitrogen per year from domestic wastewater. Similarly an average
value for phosphorus in wastewater is 3 pounds per capita per year,
which would result in a discharge of 1,410 pounds phosphorus per
day or 256 tons per year in domestic wastewater in the basin. These
estimates assume typical low removal efficiencies of these constituents
in wastewater treatment. In the case of nitrogen, the form may
merely be changed, i.e., to ammonia or to nitrate. In the case of
phosphorus, it may be converted from organic phosphates to ortho-
phosphate.
Major sources of industrial wastes in the basin are an anhydrous
ammonia plant and several packing plants. Information from the
records of the Iowa State Department of Health indicates that ap-
proximately 2,300,000 pounds of live weight of beef and hogs are
killed each weekday at the packing plants in the basin above Boone.
These plants will have losses of about 1 pound N and 0.1 pound P
per 1,000 pounds live weight killed, based on a U.S. Department of
Health, Education and Welfare publication (1954) and based on
sampling experience of the authors. These losses would thus total
about 2,300 pounds N and 230 pounds P each weekday or 300 tons
N and 30 tons P yearly. The fertilizer plant contributes comparatively
little N and no P to the Des Moines River. Most of these nutrients will
be discharged in treated wastewater to the Des Moines River.
The possible losses of nutrients from growing corn, the dominant
crop in the 5,490 mi2 basin, can be estimated based on crop patterns.
The harvested area of corn in 1968 in Iowa is believed to be about
10,200,000 acres (USDA Economic Research Service and Statistical
Reporting Service, 1964), and if the watershed is assumed to have a
proportionate acreage in corn the watershed corn acreage would be
1,000,000 acres. Timmons et al. (1968) have shown that with 3
inches of runoff 20.3 pounds per acre of nitrogen was lost annually
from continuous corn plots. If this value is accepted for discussion
purposes, then corn acreage in the basin could have contributed
approximately 10,000 tons of nitrogen annually to the Des Moines
River above Boone.
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352 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
Timmons et al. (1968) also found that phosphorus losses with 3
inches of runoff from continuous corn plots were 0.2 pounds per acre.
If this value is accepted, then the 1,000,000 acres of cornfields in the
watershed could lose 100 tons of phosphorus annually to the river.
Since corn is the predominant row crop in Iowa and receives 95%
of the applied commercial fertilizer (USDA, ERS and Stat. Rep. Serv.,
1964), no estimate was made of the nutrient contributions from
other crops or noncultivated land.
A rough estimate can be made of nutrient contribution to the
Des Moines River from animal wastes. Loehr (1969) has presented
data indicating hogs produce wastes with 0.05 pound N and 0.03
pound P2O5 per 100 pounds animal weight per day. Beef cattle
produce wastes with 0.40 pound N and 0.12 pound PoO-, per 1,000
pounds animal weight per day. Since we have 6,100,000 swine and
3,300,000 beef cattle on feed in Iowa at any one time, it is possible
to calculate their pollution potential. In making this estimate it was
assumed that the distribution of animals was uniform thrcughout
the state, the average animal was half-grown, and 25% of the ani-
mal waste nutrients (a guess) were lost in runoff. Based on these
assumptions, the quantities of nutrients lost from feedlots in the
basin each year could well approximate 3,600 tons N annd 500 tons
P. Additional quantities of nutrients are lost from poultry and dairy-
ing operations but are not included in this estimate.
The N and P estimated from these sources are tabulated in Table
25.1. These estimates can now be compared to the gross amounts
determined from actual stream data collected between 1967 and
1969. Analyses for the various forms of nitrogen and orthophosphate
were made weekly from samples collected from the flowing river
water. No analyses were made of bottom sediments, but during high
flow periods the water was highly turbid and contained large quanti-
ties of sediment. The analyses were performed according to the pro-
cedures outlined in "Standard Methods" (American Public Health As-
sociation, 1965). Since the test for orthophosphate is performed in
an acid medium, part of the phosphate adsorbed on sediment is de-
sorbed and detected by this method.
The concentration of N and P in the Des Moines River at Boone,
based on these weekly analyses, is shown in Figure 25.1, together
with river flows. Similarly, Figure 25.2 shows the pounds per day of
N and P in the river at Boone.
During the first year of the study (1967—1968) rainfall was below
TABLE 25.1. Estimated sources of nitroqen and phosphorus in the Des Moines
River basin above Boone, 1968.
Ton N/Yr Ton P/Yr Lb N/Day Lb P/Day
Domestic wastewater
Packinghouse wastes .
Animal \vastes
Agricultural losses . .
860
300
3,600
10,000
256
30
500
100
4,700
1,650
20,000
55,000
1,410
165
2 700
550
Total 14,760 886 81,350 4,825
-------
-DISCHARGE, cu ft/sec
-PHOSPHORUS, mg/1
-NITROGEN, mg/l
AUG ' SEF ' OCT 'NOV1 DEC
1967
1968
1969
FIG. 25.1. Concentration of nutrients and flow in the Des Maine?
River at Boone, Iowa.
>! 54,0
24,OOC
I.XC
i:,occ
-DISCHARGE, cu ft/sec
-PHOSPHORUS, Ib/day -
-NITROGEN, Ib/day —
JUL ' AUG ' S£f OCTODtC
1967
'
WAI ' Af« 'MAY' JUN ' JUL ' AUG ' SEP ' OCT 'NOV' etc aiii'm 'MAI ' A/I
1968
1969
FIG. 25.2. Pounds of nutrients per day and flow in the Des Moines
River at Boone, Iowa.
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354 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
-DISCHARGE, cu ft/sec
t.ox
-TURBIDITY. JACKSON TURBIDITY UNITS
-CHLOROPHYLL A, mg/1
J'Jl ' AUG ' 2f ' OCI 'MOV' DEC I JAN I Fll ' MAI '< AM 'MAY1 JUN ' JU. ' AUG ' SEP ' OC7 'MOV1 Of C I JAN 'HI ' M*l ' AM '
1967 I 1968 I 1969
FIG. 25.3. Chlorophyll A, turbidity, and flow in the Des Moines River
at Boone, Iowa.
average, totaling 26.8 inches at Boone and only 18.4 inches at the
Des Moines airport. As a result, runoff and river flows during this
period were exceptionally low. Nitrogen levels were lower than the
estimated wastewater contributions for most of this year. Under these
conditions of flow and low turbidity, high concentrations of chloro-
phyll A, a measure of algal activity, were found, as shown in Figure
25.3. Figure 25.4 is a plot of the nitrogen and chlorophyll data dur-
ing winter to summer at this low flow period. The dashed lines at
6,350 pounds nitrogen per day represent the amount of nitrogen ex-
pected in the river water from domestic and industrial wastewater.
Several researchers (Willrich, 1969) have reported drain tile
concentrations of 15 to 25 mg/1 of nitrate N and O.I mg/1 of P. On
this basis, we might conclude that groundwater entering the river
during the low flow periods might approximate these same levels of
N and P. Howrever, we have no real data to indicate the groundwater
contributions of N and P from this source, and have attributed all of
the N and P in the river during low flow periods to municipal and
industrial wastes. The uptake of nitrogen by algae and attached
plants can account for the fact that the quantities of nitrogen ob-
served were lower than the estimated wastewater contributions for
extended periods.
The second year of the study (1968—1969) was a wet period dur-
ing which rainfall totaled 37.8 inches at Boone. During the second
year, when runoff and the river flows were relatively low, the nitrogen
content of the river water was approximately at the level estimated to
-------
24,000
16,000
8,000
0
1.2
0.8
0.4
0.0
1,200,000
800,000
400,000
0
f~\ II OPl^DIIVl 1 A , i i /! -—
L-nLUKUrli rLL A my/I — • • •
NITROGEN, Ib/day
DOMESTIC
AND INDUSTRIAL
WASTEWATER
(6,350 Ib N/day)
i i1,
' wj s
JJWUCTW A ,
JAN FEB MAR APR MAY i JUN
1968
FIG. 25.4. Nitrogen, chlorophyll A, and flow in the Des Moines River
during a dry period.
-------
DISCHARGE , cu ft/sec -
-CHLOROPHYLL A, mg/1-
•NITROGEN, Ib/day
DOMESTIC
AND INDUSTRIAL
WASTE WATER
(6,350lbN/day)
JAN I FEB ' MAR I APR I MAY ' JUN '
1969
FIG. 25.5. Nitrogen, chlorophyll A, end flow in the Des Moines River
during a wet period.
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CHAPTER 25 / ADVANCED WASTE TREATMENT FEASIBILITY / 357
result from the continuous domestic and industrial wastewater con-
tribution. At times of high runoff and river flow, the nitrogen con-
tent was correspondingly high. Figure 25.5 shows the relationship
between nitrogen content, flow, and chlorophyll A during winter to
summer of the wet year. It is apparent that during low flow periods
mestic and industrial wastewater is the principal source of nitrogen.
During high runoff periods, large quantities of nitrogen are entering
the stream over extended periods of time; but due to high turbidity,
algal growth is low.
By assuming that the product of the weekly analysis for nitrogen
and flow represented the average weekly nitrogen load, it was possi-
ble to compute the weekly and annual nitrogen load to the river. The
values for the weeks of incomplete data were estimated. The annual
nitrogen totals for the first and second years were 2,207 and 24,230
tons, respectively. During the first year, the first 2 weeks and the
last week were exceptionally wet. When these 3 weeks were elimi-
nated, the river nitrogen content during the remaining 49 continuous
weeks was 647 tons. The nitrogen total during these 49 dry weeks
was 60% of the estimated wastewater nitrogen. The nitrogen total
for the second wet year was 164% of the estimated combined waste-
water, animal waste, and agricultural loss contributions. Apparently
during a wet year the additional nitrogen derived from runoff is equal
to about 31 % of all the nitrogen contained in the fertilizer and animal
wastes generated that year in the basin. Annual gross nitrogen in-
puts originate from many sources, including mineralization of or-
ganic matter, animal waste, commercial fertilizers, and that received
from the atmosphere by legume fixation, soil absorption, precipita-
tion, and dust sedimentation. The exact quantities derived from each
source have not been and cannot be determined from the data in
this study.
BOD loads in the river also increased dramatically during periods
of peak runoff. During the dry first year the average BOD load was
28,100 pounds per day, the equivalent of untreated wastes from a
population of 165,000. During the second wet year the average BOD
load in the stream was 127,000 pounds per day, the equivalent of
untreated wastes from a population of 750,000. The peak BOD dur-
ing the second year, experienced on March 26, was 916,000 pounds
per day. The carbonaceous BOD (subtracting the oxidation of ni-
trogenous compounds) was equivalent to untreated wastes from a
population of 4,200,000. These values demonstrate the effect of
runoff on stream quality in a watershed where the total population
is 238,000.
Figures 25.1 and 25.2 also show the concentration and pounds
per day of phosphorus in the river at Boone. Only orthophosphate in
the flowing water was measured and no analysis was made of or-
ganic phosphate, phosphorus in bottom deposits, etc. Figure 25.6
shows winter and summer data during this low flow period. The
dashed line at 1,575 pounds P per dav represents the amount of phos-
phorus expected from domestic and industrial wastewater sources.
During this first year of the study, the dry conditions resulted in little
runoff. Much of the phosphorus in the wastewater either precipitated
-------
24,000
16,000
8,000
—
0
1.2
0.8
0.4
—
0
36,000
8,000
4,000
—
0
Pill OPODIIVI 1 A in.- A
\~l\\.\Jf(\Jl 1 \ YLL A, Ilig/l
PHOSPHORUS, Ib/day
DOMESTIC
AND INDUSTRIAL
WASTEWATER
(l,575lbP/day)
*
\ \
1 r
1 A ^ I A
A/ • • \
_^^ /^ _^ii
JAN 1 FEB~~1 MAR T^APR IMAY1 JUN 1
1968
FIG. 25.6. Phosphorus, chlorophyll A, and flow in the Des Moines
River during a dry period.
358
-------
24,000
16,000
8,000
1.2
0.8
0.4
0.0
36,000
24,000
12,000
-DISCHARGE, cu ft/sec
•CHLOROPHYLL A, mg/1-
•PHOSPHORUS, !b/day
DOMESTIC AND
INDUSTRIAL
WASTEWATER
(l,575lbP/day)
JAN I FEB I MAR I APR I MAY I JUN
1969
FIG. 25.7. Phosphorus, chlorophyll A, and flow in the Des Moines
River during a wet period.
359
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360 / PART 5 / AGRICULTURAL POLLUTION IMPLICATIONS
out or was utilized by algae (which were present in unusually high
concentrations), resulting in low levels in the stream.
Figure 25.7 illustrates the river phosphorus content during the
winter and spring of the year (1968-1969). During this wet period
when runoff and river flows were high, phosphorus levels rose to as
high as 19 times the level expected from wastewater alone. At low
river flows the phosphorus levels were again well below the domestic
and industrial wastewater level. Apparently the phosphorus is asso-
ciated with channel scour and bottom sediments. It is interesting to
note that the phosphorus levels both increased and decreased faster
than the river flows, indicating that the phosphorus was bound to
sediment particles.
As with the nitrogen data, it was assumed that the product of
the weekly analysis for phosphorus and flow represented the average
weekly phosphorus load in the river. The values for the weeks of in-
complete data were estimated. The annual phosphorus totals for the
first and second years were 50 tons and 1,653 tons, respectively. The
total for the first dry year is 18% of the estimated domestic phos-
phorus alone. The total for the second wet year is nearly 6 times the
estimated wastewater phosphorus alone and 186% of the estimated
combined contributions from wastewater, animal wastes, and agri-
cultural losses. The additional phosphorus in the stream derived
from runoff during a wet year is equal to about 6% of all the phos-
phorus contained in the applied fertilizer and animal wastes gener-
ated in the basin.
Based on the assumptions made in this analysis, it would appear
that treating domestic and industrial wastewater to remove the nu-
trients will benefit the receiving stream only during dry weather
flows, given present inputs from all other sources. During wet
weather most of the nutrients in the water will originate from sources
other than domestic and industrial wastewaters.
CONCLUSIONS
The protection of the quality of water in Iowa streams requires
that attention be directed at the various contributors of the significant
pollutants. Attention is currently being directed at municipal and
industrial waste discharges, since these enter streams through a
point source and are easily controlled. All such wastes must be given
secondary treatment prior to discharge to Iowa's streams. As more
stringent treatment requirements are demanded in the future, there
is some question as to whether nutrient removals from municipal and
industrial wastes will be sufficient to protect the stream.
This study indicated that during periods of dry weather when
light and turbidity conditions are favorable for phytoplankton growth,
the principal source of the N and P required to support such growth
is derived from municipal and industrial wastewater discharges. Re-
moval of N and P from such wastewater discharges will help reduce
phytoplankton growth.
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CHAPTER 25 / ADVANCED WASTE TREATMENT FEASIBILITY / 361
In periods of high stream flow, when turbidity levels are high
enough to be unfavorable to phytoplankton growth, runoff from urban
and rural lands and channel erosion are probably the principal con-
tributors of N and P to the stream. Removal of N and P from mu-
nicipal and industrial wastes during these periods will not reduce
nutrient levels significantly. However, these are not the periods
when eutrophication is a problem in flowing streams. In those situa-
tions where the stream flow is impounded, the runoff sources pre-
dominate and the clarified water in the reservoir will support large
phytoplankton blooms. Under the latter conditions, tertiary treat-
ment of municipal and industrial wastes will be of less benefit until
runoff contributions of N and P are also controlled.
REFERENCES
American Public Health Association. 1965. Standard Methods for
the Examination of Water and Wastewater. 12th ed. New York.
Corey, R. B., Hasler, A. D., Lee, G. F., Schraufnagel, F. H., Wirth,
T. L. Jan. 1967. Excessive water fertilization. Rept. to Water
Subcommittee, Nat. Resources Committee of State Agencies,
Madison, Wis.
Dept. of Civil Engineering. Oct. 1966-Sept. 1967. Annual rept.
Coralville project. Univ. of Iowa, Iowa City.
Engineering Research Institute. Fiscal year 1968-69. Preimpound-
ment water quality study, Saylorville reservoir, Des Moines
River, Iowa. Sanit. Eng. Sec., Iowa State Univ., Ames.
Iowa Natural Resources Council. 1953. An inventory of water re-
sources and water problems, Des Moines River Basin. Bull. 1.
Iowa Water Pollution Control Commission. Apr. 1969. Statement in
support of the Iowa water quality standards and plan for imple-
mentation and enforcement, Mississippi River Basin.
Loehr, Raymond C. 1969. Animal wastes—a national problem. /.
Sanit. Eng. Div. Am. Soc. Civil Engrs. 95(SA2): 189.
National Fertilizer Development Center. 1968. Fertilizer summary
data 1968. TVA, Muscle Shoals, Ala.
Sauchelli, V., ed. 1960. Chemistry and technology of fertilizers.
Am. Chem. Soc. Monograph Ser. 148. New York: Reinhold.
Shobe, William R. 1967. A study of diatom communities in a hard-
water stream. Unpublished Ph.D. thesis, Iowa State Univ.,
Ames.
Sulphur Institute. 1969. Potential plant nutrient consumption in
North America. Tech. BuU. 16, Wash., D.C.
Task Group 2610-P Report. 1966. Nutrient-associated problems in
water quality and treatment. ]. Am. Water Works Assoc.
58(10): 1337.
1967. Sources of nitrogen and phosphorus in water supplies.
J. Am. Water Works Assoc. 59 (3): 344.
Timmons, D. R., Burwell, R. E., and Holt, R. F. 1968. Minnesota
science. Univ. of Minn. Agr. Exp. Sta. 24 (4).
USDA Economic Research Service and Statistical Reporting Service.
1964. Fertilizer use in the United States. 1964 estimates, Sta-
tistical Bull. 408.
-------
362 / PART 5 / ACJRiCyiTUAAL POllUT ifcfl
U.S. Dept. of Health, Educaiion and Welfare. 1954. An i,'sdus'.riai
waste guide to the 'meat industry. Publ. 386.
. 1962. Plankton 'population dynamics. Nail. Water Onaliiy
Network Suppl. 2, Public Health Serv. Publ, 663.
Van Wazer, V. R. 1361. Phosphorus and its compounds, ii. Tech-
nology, biological functions, and applications. New York. Inter
science Publishers,
Willrich, Ted L, 1969, Personal communication. Agr, Er.g E>:i ,
Iowa State Univ., Ames.
-------
PART SIX
AGRICULTURE'S INVOLVEMENT IN
POLLUTED AND CLEAN WATER
-------
CHAPTER TWENTY-SIX.
LEGAL ASPECTS
N. WILLIAM HINES
IN view of the preceding extensive technical discussions, it is
unnecessary to emphasize the "iceberg" character of agriculture's
contribution to the pollution load carried by our waters. The highly
publicized forms of agricultural pollution, such as the wastes from
concentrated feedlot operations, are analogous to the tip of an ice-
berg—they signal the presence of a much larger mass of pollution
that exists just below the surface of visibility. The law's present
concern with agricultural pollution reflects and reinforces this dis-
tinction between overt instances of pollution from identifiable point
sources and subtle, broad-gauge pollution from materials carried to
waterways through surface runoff and underground drainage from
agricultural lands. Thus far, the law recognizes and enforces some
duties in respect to agricultural pollution from point sources and has
created regulatory schemes to control this type of pollution. Little
legal attention, however, has been devoted to the larger problem of
nonpoint pollution from land runoff containing animal and vegetable
wastes, agricultural chemicals, and silt. Because this book brings
together experts from so many disciplines, I will assume that my
specific responsibility as a representative of the legal community
is twofold: (1) to describe what the law now requires and permits in
the area of water pollution from agricultural sources, and (2) to sug-
gest how the law might constrain or promote the implementation of
pollution policy changes affecting agricultural production.
PRIVATE LAW DUTIES OWED LOWER RIPARIAN OWNERS
Under the common law doctrine of riparian rights, which was
uniformly adopted in the eastern United States, rights and duties re-
lating to water use were incident to the ownership of land on the
banks of a watercourse. Each riparian owner was said to have a
right to use the water that flowed by for any beneficial purpose so long
as his use did not unreasonably interfere with the use of the com-
mon watercourse by another riparian owner. Stated in water quality
terms, the right of each riparian owner was said to be that of having
N. WILLIAM HINES is Professor of Law, University of Iowa.
365
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366 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
the water flow by his land "unimpaired in quality." This was inter-
preted to mean that he had a right to receive the water in a quality
state reasonably suitable for the use he wished to make of it. If
some upstream riparian user was diminishing the water quality be-
low this level, his pollution was actionable and the injured riparian
could sue for damages or could seek to enjoin the polluting activity.
The technical form of action under which such suits were brought
is called nuisance; therefore, you frequently see this private law ap-
proach referred to as the "nuisance theory."
The essence of private nuisance is an interference with a prop-
erty owner's use and enjoyment of his land, and under the riparian
theory water rights are an incident to the ownership of riparian land.
A nuisance may be either private or public, depending upon whether
it harms only a few persons or affects the interests of the general
public. For example, stream pollution that damages only isolated
downstream users is a private nuisance, but if the pollution causes a
fish kill, it is a public nuisance. If the nuisance is public, it subjects
the polluter to criminal punishment, and actions to abate it may be
brought by public officials (see Prosser, Laiv of Torts, 605-23 [1964]).
In many states the nuisance concept has been legislatively en-
dorsed and the procedures for remedying the situation specified by
statute. For example, Iowa Code provides:
657.1 Nuisance—what constitutes—action to abate.
Whatever is injurious or offensive to the senses, or an obstruc-
tion to the free use of property, so as essentially to interfere
with the comfortable enjoyment of life or property, is a nui-
sance, and a civil action by ordinary proceedings may be
brought to enjoin and abate the same and to recover damages
sustained on account thereof.
657.2 The following are nuisances:
(4) The corrupting or rendering unwholesome or impure the
water of any river, stream, or pond, or unlawfully diverting
the same from its natural course or state, to the injury or
prejudice of others.
Relatively few reported cases can be found in which agricultural pol-
lution has been attacked as either a private or public nuisance. In
fact, no higher court case can be found where a nuisance suit was
brought to remedy an injury caused by water-borne agricultural
chemicals or silt. A look at a recent private nuisance action arising
in Kansas as the result of pollution caused by feedlot wastes should
serve to illustrate the application of the nuisance law.
Some of you may be familiar with the litigation which reached
the Kansas Supreme Court in 1968 under the title Atkinson v. Her-
ington Cattle Company (200 Kan. 298, 436 P.2d 816). To my know-
ledge it is the only feedlot pollution case to be decided by a state su-
preme court in the modern era. Under the facts alleged, farmer Cecil
Atkinson's water supply for his Grade A dairy operation was Level
Creek and a well 400 feet distant from the creek. The Herington
feedlots, on which were fed as many as 7,500 cattle, drained into
Level Creek 1\4 miles upstream from Atkinson's farm, causing the
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CHAPTER 26 / LEGAL ASPECTS / 367
water, as it passed through Atkinson's property, to have a foul ma-
nure odor and a dark yellow-brown color. The water in Atkinson's
well had many of the same properties and was grossly unfit for hu-
man or animal consumption. Atkinson sued Herington and Swift
and Company jointly, claiming the latter party was a joint venturer
in the feedlot enterprise, the cattle being supplied by Swift and fed
by Herington on a contract basis. Evidence was submitted by a host
of expert witnesses, including bacteriologists, chemists, geologists,
and sanitary engineers. Veterinarians testified that Atkinson's cows
had died from nitrate poisoning. The trial court awarded Atkinson
$29,060 actual damages and $7,500 punitive damages against both
defendants jointly. Punitive damages are awarded in cases where the
defendant is deserving of punishment for his willful and malicious
invasion of another person's rights. The purpose of such an award
is to make an example of the defendant and thereby deter others
from the commission of like wrongs.
On appeal, the Supreme Court sustained the actual damage
award, but denied the punitive damages. The court said that al-
though there was conflict over the details of how the water became
polluted and the precise physical effects of the pollution, ample evi-
dence existed to support the lower court's finding that Herington
had unreasonably polluted Level Creek and that Atkinson's damages
resulted from that pollution. The court's statement of its ruling was
as follows: "Runoff becomes a harmful substance when it combines
bacteria and chemicals in such an amount as to produce excessive
pollution resulting in injury." On the punitive damage issue, the
court found the evidence inadequate to support the awarding of
such exemplary damages because the evidence showed that Hering-
ton took immediate, although as it developed ineffective, steps to try
to remedy the situation upon receiving the first complaint from At-
kinson.
Because in this case the injured party recovered substantial
damages from the agricultural polluter, it should not be inferred that
such is always the result. Nuisance cases are generally hard to win
for a variety of factors, including the difficulties of proving the source
and effect of the alleged pollution, the possibility that a complaint is
not made quickly enough to protect the right asserted, and the will-
ingness of the courts to engage in a balancing process which pits the
social utility of the polluter's economic activity against the personal
loss of the complainant. Additionally, courts of law are not particu-
larly well suited to the determination of the typical pollution suit.
The perceived inefficiency in placing direct reliance on the judicial
system to control pollution is the reason we presently assign the
major responsibility in this area to public pollution control agencies.
REGULATION OF AGRICULTURAL POLLUTION
BY PUBLIC AGENCIES
Public regulation of pollution generally is carried on by control
agencies established by local, state, interstate, and federal govern-
mental units. Traditionally, pollution control by state level agencies
-------
368 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
has been the mainstay of water quality regulation, Nearly every
state has a pollution control law administered by a separate agency
of a special division within a larger agency (see Hines, Nor Any Drop
to Drink: Public Regulation of Water Quality Part I: State Pollution
Control Programs, 52 Iowa L. Rev. 186 [1966]). The concentration
of control activity at the state level continues to hold true today;
however, Congress's enactment of the Water Quality Act of 1965 inter-
jected the federal government very directly into the business of pol-
lution control on most of the nation's waterways. The 1965 Act re
quired the establishment of federal water quality standards for all of
the interstate waters in the country. As defined by federal authori-
ties, nearly all larger streams, rivers, and lakes are interstate waters.
The 1965 Act authorized the individual states to develop standards
for the waters within their jurisdiction, but required that these stand-
ards be acceptable to the federal government.
If you read the newspapers, you know that the establishment
of federal standards has led to a number of serious disputes between
state pollution control agencies and the federal officials responsible
for approving the standards adopted by the states. Although a num-
ber of the states in the Missouri and Mississippi basin have en-
countered problems in obtaining approval of their standards, Iowa
has been the chief antagonist of the FWPCA's requirements for ac-
cepting state standards. This dispute came to a head when Secre-
tary of Interior Hickel announced on October 29, 1969, that he was
imposing federal standards on Iowa, the first action of its kind under
the 1965 Act.
This is probably not a good occasion to air in detail the dispute
between the Iowa Pollution Control Commission and the FWPCA;
however, it is worthy of note that the major issue is the requirement
of secondary treatment for all sewage discharged into Iowa's 27 in-
terstate streams. Other standards imposed relate to water tempera-
ture, phenols, and continuous disinfection of all municipal waste.
Only the standard limiting phenol levels to one part per billion
would appear remotely related to agricultural pollution. That stand-
ard speaks in terms of phenols "from other than natural sources,"
so arguably phenols produced by decomposition of vegetative agricul-
tural wastes may not be covered by the standard because, except in
a rare case, it would be impossible to distinguish these from phenols
produced by decomposition of natural vegetation. On a more general
level, it is worthy of note that the federal Guidelines for Establish-
ing Water Quality Standards make no specific mention of regulation
to control agricultural pollution, nor has the FWPCA's application of
these standards demonstrated any immediate concern for problems
of agricultural pollution, except in a research capacity.
It thus seems a safe conclusion that the current furor around
the country over the establishment of water quality standards has
very Little to do with agricultural pollution. Municipal and industrial
pollution are the immediate targets of the federal-state effort to peel
back the flood of pollutants. Only when these obvious point sources
of pollution are brought under control is attention likely to shift to
cleaning up agriculture's insidious wastes. Given the present rate
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CHAPTER 26 / LEGAL ASPECTS / 369
of success in controlling municipal and industrial wastes, it will
probably be some time before the spotlight shifts to agricultural pol-
lution. Two notable exceptions exist to the current disinterest in ag-
ricultural pollution. Pollution control agencies have taken a direct
interest in the regulation of feedlot wastes and chemical pesticides
used in agriculture and have attracted widespread attention. Both
of these areas deserve special comment. The pollutional effects of
chemical fertilizers and soil erosion have received much less atten-
tion. No regulatory interest has been addressed to the enormous
volume of animal and crop wastes periodically washed into streams
by surface runoff from agricultural lands. Some experts suggest that
shock loads of these organic materials that reach watercourses as the
result of heavy rains or rapid thaws pose the most serious agricultural
pollution problems (see Morris, Pollution Problems in Iowa, Paper
presented to the Iowa Academy of Sciences, April 18, 1969).
Regulation of Feedlot Wastes
At the outset it should be noted that pollution resulting from
concentrated feedlot operations is a type of agricultural pollution
that is fundamentally different from the great bulk of agriculture's
contribution to the pollution load of our waters. Feedlot pollution
emanates from a readily identifiable source—it is point pollution—
and it is susceptible to the same types of treatment procedures as are
applied to municipal wastes and organic industrial wastes. The simi-
larity of feedlot pollution to municipal and industrial wastes, phis
its severe pollutional effects (a feedlot of 20,000 cattle is said to pro-
duce a waste with a population equivalence of a city of over 300,000
people), no doubt explains the prevalence of efforts to regulate feed-
lot wastes in the midwestern states where this type of agricultural
practice is popular.
Several states have enacted legislation regulating the waste
discharge practices of feedlots. The Kansas statute, for example,
provides that any feedlot operator feeding more than 300 cattle, 100
hogs, or 500 sheep must register with the health department and
provide pollution control faculties if needed to prevent pollution run-
off from the premises (Kan. Stat. Ann. 47-1505). Arizona requires
feedlot operations with more than 500 cattle to obtain a license and
co provide reasonable methods to dispose of excrement and control
drainage (Ariz. Rev. Stat. Ann.§§ 24-391-397). In most other states,
the pollution control agencies are working to promulgate regulations
relating to feedlot wastes under their general power to make rules
and regulations necessary to perform their regulatory function. Con-
siderable discussion has centered on what a good regulation should
provide (see Matthews, A Recommended Procedure for Developing a
Model Feedlot Regulation, proceedings of Animal Waste Manage-
ment Conference, Cornell Univ., Ithaca, N.Y., 1969).
Iowa's recently promulgated regulation covering cattle feedlots
is worthy of note. In 1968 hearings conducted around the state on
proposed feedlot regulations provoked considerable interest in agri-
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370 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WAUR
cultural circles. The 1969 session of the Iowa legislature amended
the pollution control law to require registration of all Livestock and
poultry operations where a potential for water pollution exists. Un-
der the amendment the Commission cannot require waste disposal
facilities unless it is determined that the registrants are in fact pol-
luting water or may reasonably be believed to threaten pollution. The
thrust of the regulations recently issued under this amendment is to
specify the feedlot situations in which a pollution potential exists,
and therefore in which registration is required. The regulations re
quire registration of cattle feedlots which confine more than 1,000
cattle or which contribute effluent to a watercourse draining more
than 3,200 acres above the lot, which watercourse is less distant than
2 feet per head of cattle, or from which the runoff flows into an un-
derground conduit or drainage well. If the control agency determines
that the registered feedlot is, or reasonably may be, a source of pollu
don, then the feedlot is required to obtain a permit for disposal of
wastewater. Permits are granted on a showing of adequate water
pollution control facilities constructed in accordance with plans arid
specifications approved by the agency. The regulation specifies ter-
races or retention ponds sufficient to contain a surface runoff of 3
inches as the minimum pollution control facility permissible.
Iowa's regulations seem to meet most of the objectives sug-
gested by Matthew iri his recommended model feedlot regulations
One facet of the regulations that is not clear relates to the enforce-
ment of the registration and permit requirements. What penalty is
incurred by failure to register a feedlot required to be registered
or failing to obtain a permit under circumstances where the regula-
tions would require a permit? If the feedlot is actually creating a
situation of pollution, the Commission can issue an abatement order
without relying on any violation of the regulations. If only a potential
for pollution exists, it is not certain what steps, if any, the Commis-
sion can take to compel compliance with the registration and permit
requirements. Presumably the permit required by the regulations is a
permit of the type covered by Iowa Code 455B.25, which makes the
construction of disposal systems or use of a new waste outlet with-
out permit an unlawful act. The feedlot operator who does nothing
about his wastes would seemingly not be guilty of an unlawful act
under this section. Iowa Code 455B.24 concerning contempt citations
for failure to obey orders of the Commission has been interpreted as
referring to abatement orders based on proof of pollution. Orders are
not ordinarily issued on a showing of pollution potential. The injunc-
tion power granted the agency under Iowa Code 455B.23 applies to
situations in which a person is placing wastes in a location where
they will probably cause pollution. Under this provision the Commis-
sion could apparently enjoin the waste disposal activity of a feedlot
operator if it appeared likely to cause pollution. This brief excursion
through the enforcement section of the Iowa law proves nothing
more than the need to make sure regulatory schemes fit the enforce
ment pattern of the statute under which they operate. If registration
is the key to controlling feedlot pollution, it appears desirable to put
some teeth in the registration requirement by indicating the penalty
for failure to comply,
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CHAPTER 26 / LEGAL ASPECTS / 371
Pesticide Regulation
Pesticides have been in the headlines for much of the last year;
not so much as water pollutants as total environment pollutants. The
so-called hard pesticides, DDT and the other chlorinated hydro-
carbons, have received the lion's share of attention, with 2-4,D and
related herbicides taking a secondary position. The toxic effect of the
existing chemical biocides on man is still hotly debated; less disputed
are the obvious incursions that have been made on the food chains
and eco-systems of lower animals.
Because they enter the environment at a multitude of contact
points, the most effective method for controlling pesticide pollution
seems to be to regulate their initial use. Almost every state has some
form of pesticide registration law that requires the filing of an in-
gredient statement, the label, and directions for use (see Iowa Code §
206.4). Many states have additional provisions regulating the use of
pesticides by commercial applicators (see Iowa Code § 206.5). These
latter statutes were primarily aimed at assuring technical competency
on the part of persons who applied chemicals for hire; they do not
reach the individual applying chemicals to his own property.
In sharp contrast to this traditional approach of minimum regu-
lation are the actions taken by several states recently in prohibiting
the use or banning the sale of certain pesticides thought to be
dangerous. Arizona declared a 1-year moratorium on the use of DDT
and DDD in January 1969. In April, the Michigan Agricultural
Commission decided to ban the sale in the state of all products con-
taining DDT. In August, Wisconsin created a Pesticide Review Board
for the purpose of governing the use of pesticides. Actions outlawing
or phasing out DDT were taken by one house of the legislature in
California, Wisconsin, and Illinois (New York Times, Apr. 30, 1969, p.
43; July 19, 1969, p. 30; Nov. 4, 1969, p. 6). This bustling of state
regulatory activity presaged the announcement by HEW Secretary
Finch on November 13, 1969, that the federal government had de-
cided to halt DDT use in this country within the next 2 years.
To appreciate the nature and extent of the federal power in this
area it is necessary to understand the federal regulation of pesticides
used in agricultural production. The Food and Drug Administration
within HEW is authorized by Congress to safeguard the safety and
quality of food products and drugs distributed in interstate com-
merce. If you remember your high school civics, you may recall that
the federal government has no general police power, but must regu-
late through the specific enumerated powers granted by the Constitu-
tion. Thus purely intrastate marketing of agricultural products is not
subject to the FDA requirements. Since the Pesticide Chemicals in or
on Raw Agricultural Commodities Act of 1954, pesticide residues
have been one of the elements of food quality the FDA has been re-
sponsible for regulating. The FDA, therefore, sets the levels of toler-
ance of pesticide residue that will be permitted on foodstuffs market-
ed in interstate commerce.
Responsibility for the regulation of agricultural chemicals mar-
keted in interstate commerce rests with the USDA under the Federal
Insecticide. Fungicide and Rodenticide Act (7 U.S.C. § 135). This act
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372 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
makes it a criminal offense to sell any "economic poison" which has
not been fully and accurately registered with the USDA. The secre-
tary of agriculture determines what chemicals are economic poisons,
and chemical biocides are uniformly so classified. Any party seeking
to register a chemical to be used on food crops must indicate the
crops on which the chemical is to be used, the quantity to be used for
each crop, and describe the exact procedure of use. Additionally, test
data must be provided to show the safety of specific residues of the
chemical in or on foodstuffs. If no residue should be left under cor-
rect application procedures, the product is registered as a "no-residue"
chemical. If a residue subsequently shows up, the registrant has
violated the act.
This is what happened in the great cranberry snafu of 1958.
The herbicide amenotraezole was registered on a no-residue basis,
then when a residue appeared because of improper use, FDA pan-
icked the buying public by announcing the confiscation of 300,000
pounds of cranberries. Testing ultimately showed that relatively few
of the cranberries were contaminated and cranberry growers were
reimbursed $8.5 million for their losses. A similar problem arose in
1963 concerning endrin residue on brussels sprouts. Endrin had
been registered on a no-residue basis at a time when the testing de-
vices could detect residues of no smaller amounts than 0.1 ppm. Im-
proved testing techniques enabled inspectors to find a 0.03-ppm resi-
due and the products were pulled from the market.
If the chemical will leave a residue, the product will not be
registered until a residue tolerance level has been set by FDA. The
tolerance level is set on the basis of information submitted to FDA
by the applicant, showing the expected amounts of residue, the effect
of such a residue on test animals, the pattern of normal use of the
foodstuff, and a workable method of analysis for enforcing the toler-
ance level. If USDA is satisfied with the tolerance level set by FDA.
the chemical is then authorized.
Thus working in concert, as they apparently plan to do, HEW
and USDA can, through reduction of the permissible tolerance levels
of DDT, eliminate its use in conjunction with agricultural products.
Critics of the federal government's past activities in pesticide control
have asserted that one of the major weaknesses has been the lack of
coordination between FDA and HEW (see Note, Agricultural Pesti-
cides: The Need For Improved Control Legislation, 52 Minn. L. Rev.
1242 [1968]). Perhaps the joint plan to phase out DDT signals a new
era in effective cooperation between these two agencies.
Lawyers active in environmental defense litigation claim that
the most difficult problem in pesticide regulation is uncovering the
scientific facts about the relative toxicity of the different chemicals.
They suggest that this difficulty could be substantially cured if the
regulatory agencies held public hearings where experts could be pro-
duced and cross-examined on the questions concerning the danger
of chemicals to various forms of life. The lawyers argue that the
adversary process used in our courts is peculiarly suitable for testing
the reliability of the evidence presented by proponents and opponents
of controversial chemicals. The one experiment with this method be-
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CHAPTER 26 / LEGAL ASPECTS / 373
fore a special hearing board in Wisconsin suggests that there is merit
in the argument for adversary proceedings before agencies charged
with protecting environmental quality. Until recently, such a require-
ment would have been meaningless because only the chemical in-
dustry would have been represented. Today, however, a number of
citizen groups are ready and able to present the case for the public
interest in a safe and wholesome environment (see Foster, Counsel
for the Concerned Conference on Law and the Environment, Sept.
11-12, 1969, Warrenton, Va.).
Looking to the future, the agricultural producer should expect
much closer state and federal regulation of both the chemicals availa-
ble to him and his procedures in applying them. Special pesticide-
regulating agencies are likely to be created by many states. From a
purely legal standpoint, given the range of uncertainty concerning
the long-range effects of pesticides on the environment, almost any
type of restrictive state regulation is likely to be sustained as a valid
exercise of the state's police power. However, chemical biocides play
such a major role in modern commercial agriculture that it is in-
conceivable that many of the other important chemicals will be dealt
with as harshly as DDT. Much more likely is regulation designed to
encourage selective use of chemicals and substitution of softer chem-
icals or biologic techniques for the more toxic pesticides. Because
pesticides entering water directly from agricultural land are believed
chiefly to travel adsorbed to sediment particles washed away by soil
erosion, more careful attention to land-use practices is likely to be
required by law.
Chemical Fertilizers
It is frequently asserted that the increasing levels of nitrates
and phosphates in midwestern waters are caused by residues from
chemical fertilizers carried to watercourses by runoff and percolation
of precipitation falling on agricultural cropland. Some experts dis-
pute this explanation, claiming that agricultural fertilizers make
only a very minor contribution to the current high levels of nitrates
and phosphates compared to the amounts contributed by natural
sources and by organic effluents discharged by municipalities and
industries (see Smith, Fertilizer Nutrients in Water Supplies, in Agri-
culture and the Quality of Environment, 1967). One point upon
which considerable agreement exists is that to the extent chemical
nutrients reach watercourses, they are principally transported there
aboard soil particles lost through erosion. Thus if chemical fertilizers
are proved to be a source of nitrate pollution, methods for controlling
silt pollution, discussed below, should have a double-barreled effect in
reducing the amount of chemicals washed into watercourses.
At present the use of chemical fertilizers is subject to no regu-
lation at either the local or national level. The legal disinterest in
chemical fertilizers is typified by the Iowa Pesticide Statute which ex-
pressly provides that in products where pesticides and fertilizers are
mixed, the fertilizer is to be treated as an inert ingredient (Iowa Code
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374 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
§ 206.4). Looking to the future, if it is proved that substantial quan-
tities of phosphates and nitrates from chemical fertilizers are wash-
ing into streams, it should be anticipated that fertilizer use itself will
be regulated. Limits could be placed on the volume and strength of
chemical fertilizers that can be applied at one time or during one
season, and controls may be adopted governing the timing and meth-
ods of fertilizer application. Such regulations would not be different
in kind from the controls now being exercised over pesticide use in
some parts of the country. There seems little doubt that whether
such controls were necessary to prevent nitrate poisoning or to re-
duce the nutrient load carried by our waters, and thereby reduce pol-
lution caused by nuisance aquatic growths, it would be a valid exer-
cise of the state's police power (see Williamson v. Lee Optical, 348
U.S. 483 [1955]; Brackett v. City of Des Moines, 246 Iowa 249, 67
N.W.2d 542 [1954]).
Silt
Recent studies on water quality in the Mississippi River show
that sediment from the over 16 million acres of Iowa agricultural
land which drains into the river will reduce the recreational value of
the river more rapidly than either municipal or industrial pollution.
Soil erosion is acknowledged to be the single largest pollutant of
nearly all mid-continent streams draining land intensively used for
agricultural production. Also, as noted earlier, soil erosion is thought
to be the principal vehicle for transporting agricultural pesticides and
chemicals from the site of their application to our waterways. Only
recently, however, has soil erosion been thought of in terms of a
water pollution problem (see Browning, Agricultural Pollution.
Sources and Control, in Water Pollution Control and Abatement
[1967]), and it is still true that the major concern is the loss to the
land of valuable soil and not the diminution in the value of waters
resulting from the silt and chemical loads imposed upon them.
Since the 1930s a substantial government effort has been com-
mitted to reducing soil erosion from agricultural land; however, little
or none of this effort qualifies as regulation in the usual sense of the
term (see Wyoming, Proposed Soil Conservation Act, 13 Rocky Mtn.
L. Rev. 115 [1941]). Essentially, what has been accomplished has
been carried out through spending programs by the state and federal
governments, the federal purse providing most of the money. The
basic unit for the prevention of soil erosion is the soil conservation
district (see Hardin, The Politics of Agriculture, 70-84 [1952]).
Generally the approach of the soil conservation districts has
been one of offering instruction and incentives for voluntary improve-
ment in soil management techniques. Financial assistance is condi-
tioned upon acceptance and performance of an approved soil conser-
vation program. Doubts have been expressed concerning the actual
enforcement of these agreements against farmers who are remiss in
performing the required conservation practices. The "tread softly"
approach of the soil conservation district is exemplified by the fre-
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CHAPTER 26 / LEGAL ASPECTS / 375
quent unwillingness to enforce an erosion control agreement against
a subsequent buyer of the land.
Gains through voluntary programs are impressive, but it seems
doubtful whether soil erosion can be brought under control without
compulsion. Through the modern concept of zoning, the law pro-
vides a viable and well-established method for accomplishing the de-
sired land-use results. Regulating the use of agricultural lands to as-
sure responsible soil management will be very difficult for many
members of the agricultural community to accept, but it is doubtful
whether any less drastic approach can achieve the requisite con-
servation objectives. In most states soil conservation districts are
authorized to adopt land-use control regulations (Iowa districts are
not granted this power) if a majority of the landowners in the district
vote in favor of such a plan. Even where it exists, the power to regu-
late agricultural practices through zoning has rarely been exercised.
Although 32 states authorize such land-use control, only a handful
of districts in 3 states have ever adopted such measures (see Parks,
Soil Conservation Districts in Action, 1952).
If the soil conservation district or conservancy district is not
able or willing to employ land-use controls, some other agency may
be expected to fill the gap. It is not unlikely that if pollution control
commissions ever turn their attention to agricultural pollution, they
may find the imposition of land-use regulation the only feasible way
to control pollution from soil erosion. Such regulation would restrict
types of plantings, prohibit certain cultivation techniques on various
soil types and slopes, and prescribe or ban a variety of soil manage-
ment practices. If the land-use control technique is used, there seems
little doubt that it would be a constitutionally valid form of regula-
tion. (For a discussion of the application of due process standards
to resource regulation see Hines, A Decade of Experience Under the
Iowa Water Permit System, Ag. Law Center Mono #9, 1966, 74-82).
An idea currently receiving considerable attention in water man-
agement circles is the proposal to create watershed authorities em-
powered to manage comprehensively the water resources and water-
related land resources of a hydrologically defined area. (For a dis-
cussion of this agency see Hines, Controlling Industrial Wafer Pollu-
tion, 9 Bos. Coll. Ind. & Comm. L. Rev. 605-11 [1968]). If such
agencies ever become a reality, they would seem to be the ideal unit
to enact and enforce land-use regulations designed to prevent soil
erosion and protect water quality. In fact, it is difficult to see how
such an agency could comprehensively regulate water quality in an
agricultural area without land-use control powers. Conferring land-
use regulation powers on a management agency, whose jurisdiction
corresponds to the physical contours of the watershed, avoids the type
of administrative problems created by the fact that soil conservation
districts are generally oriented to political boundaries rather than
drainage patterns. Some states have already adopted legislation au-
thorizing creation of watershed districts for the purpose of managing
and conserving water and water-related land resources. (Nebraska
and Minnesota have such statutes, Timmons & Bromm, Nebraska
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376 PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
Water Resource Districts, Nebr. Ag. Econ. Report No. 49; 9 Minn.
State. Ann. § 112.34-85 [1964]).
It may well be that rural watersheds containing primarily agri-
cultural water users will be the most practical place to test the water-
shed management model. Concentrations of people and industry cre-
ate factors that may militate against organizing the management
agency on a purely hydrologic basis.
CONCLUSION
The force of the law has not been brought to bear on agriculture
as it has on other major sources of water pollution. Agricultural pol-
lution has thus far been ignored because it is less visible and more
difficult to correct than are wastes from municipalities and industry.
Currently, only those types of agricultural pollution that are obvious
and subject to direct control receive legal attention. As water quality
regulation in this country matures and point sources of pollution are
brought under control, agriculture's more subtle contributions to the
undesirable properties of our wastes will attract regulatory concern.
In the background, the private law will continue to provide a remedy
for the individual who can prove a direct harm caused by pollution
and can conclusively identify the polluter.
Public regulation of agricultural pollution will take two primary
forms: (1) direct restrictions on the use of chemical inputs to agri-
cultural production, and (2) regulation of land-use patterns and prac-
tices. Examples of the first type of regulation are prohibitions or limi-
tations on the use of certain chemical biocides, fertilizers, and other
additives. Assuming a reasonable case can be made for the need for
such regulations, no legal constraints exist to their enactment and en-
forcement.
In the second category, land-use regulations seem very likely to
be necessary to effect a meaningful reduction in the soil erosion cur-
rently darkening streams, constricting waterways, filling reservoirs
with siltation, and transporting chemicals from field to watercourse.
The ideal construct might involve the employment of land-use con-
trols by a comprehensive watershed management authority. If this
does not come to pass, exercise of such powers by other local districts
such as soil conservation districts, conservancy districts, or drainage
districts would be feasible, as would granting similar powers to the
local pollution control agency.
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CHAPTER TWENTY-SEVEN
ECONOMIC ASPECTS
JOHN F. TIMMONS
all the industries in the United States, agriculture pos-
sesses the greatest potential for affecting the quality of the nation's
water resources. In fact agriculture's potential for lowering water
quality appears greater than that for all other industries in the United
States combined. This potential arises from the fact that agricul-
tural activities are scattered over most of the nation's surface, with
access to practically all the nation's waters. This potential is aug-
mented by modern technologies involving chemicals, concentrated
feedlots, tillage practices, irrigation systems, and drainage networks.
This potential exists even though less than 5% of the nation's people
are engaged in agriculture, which produces about 5% of the gross
national product.
DEFINITION OF TERMS
In this chapter the term agriculture is limited to food and fiber
production on the nation's farms, ranches, feedlots, gardens, and
plantations. All firms that process agricultural products or manufac-
ture agricultural inputs are excluded from this definition.
Water quality refers to all properties of water which affect its
use. The term pollution is not used in this chapter because it not
only differs in meaning among people but also has become emotion
laden, thereby interfering with the communication of objective ideas.
Instead, quality levels of particular water supplies viewed in terms of
particular quality levels demanded for specific purposes are used.
The term management means that water quality can be altered
and affected by purposeful and positive actions of private and public
entities and by combinations of the two. Management applied to
water quality is regarded as motivated by minimizing disutilities and
maximizing utilities in the use of water in the interest of increasing
net satisfactions available to people.
JOHN F. TIMMONS is Professor of Economics, Iowa State University.
Journal Paper No. J-6469 of the Iowa Agricultural and Home Eco-
nomics Experiment Station, Iowa State University, Project No. 1445.
377
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378 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
ROLE OF ECONOMICS
Water quality management decisions (including quality stand-
ards, demand-supply interrelationships, implementing water quality
changes, and cost allocations incurred by such implementations) in-
volve the use of the science of economics. Economics is primarily
concerned with decision-making processes in allocating scarce re-
sources among multiple and frequently competing ends in a manner
that offers maximum net benefits for the decision maker and his
clientele. Since waters of particular qualities are scarce and their use
demands are competitive, water management comes within the pur-
view of economic analysis. However, the usefulness of economic anal-
ysis in planning, programming, and implementing water quality
needs and adjustments is limited by the physical and technological
data available to the economist.
Economic analysis will yield results no better than the physical
and technological coefficients with which the economist works. And
the results may be even less useful unless the economist adapts his
theories, models, and tools of analysis to the unique and complex
problems of water quality. This means that the economist must work
closely with agronomists, engineers, biologists, hydrologists, geolo-
gists, limnologists, and other scientists in our multidisciplinary
search for ways and means of making qualities of waters serve man-
kind's needs. Our work here at Iowa State with Professors Johnson,
Baumann, Willrich, Dougal, and other engineers, as well as our work
with Professors Shrader, Moldenhauer, and other agronomists, is
illustrative of the nature of water research which is both productive
and satisfying.
OBJECTIVES
The general purpose of this chapter is to present some of the
more relevant economic concepts that with the work of other sciences
will help to assess and explain agriculture's role in water quality
management in terms of the associated problems and their remedies.
This general purpose may be restated in terms of three specific
questions:
1. What levels of water quality are desired?
2. How may these desired levels of water quality be provided at the
least cost to all users, including agriculture and the public?
3. How may costs and benefits of managed changes in water
quality be assigned among users, including agriculture and the
public?
QUALITY HETEROGENEITIES OF WATER SUPPLIES
AND WATER DEMANDS
Historically, the quantity theory of water buttressed by the sev-
eral doctrines of water rights has tended to impute homogeneous
properties to all water or at least to specific hydrologic units. How-
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CHAPTER 27 / ECONOMIC ASPECTS / 379
ever, it has become increasingly obvious that water is extremely
heterogeneous in terms of (1) its properties, (2) its permitted uses,
and (3) its demanded uses. Modern technologies with their fallouts
and wastes affecting water quality, multiple demands for water each
with specific quality requirements, and increasing population densi-
ties emphasize quality to the extent that the quality theory of water
equals and frequently exceeds the importance of the traditional
quantity theory.
From an economic viewpoint it is helpful and realistic to think
of water in terms of many water factors (productive) and numerous
water commodities (consumptive). Water may be regarded as differ-
entiated in terms of kinds and grades by its quality as linked with
spatial and temporal occurrences (Ackerman and Lof, 1959).
Let us examine this concept further by delving into (1) quality-
differentiated water supplies and (2) quality-differentiated demands,
each associated with spatial and temporal availabilities.
Water Supplies Quality Differentiated
The common chemical formula for water, H2O, has tended to
impute a homogeneity to water which actually does not exist. To
H2O must be added other chemicals, compounds, organisms, tem-
perature, color, and all other characteristics relevant to its use. Thus,
water as found in its several sources is not a simple compound but
may become very complex. This complexity varies among existing
supplies and conditions of use. These variations are introduced by
natural as well as by man-made actions. These variations are com-
pounded by variations in spatial and temporal occurrences of water
even within and among segments of the same water source.
The quality of a particular water supply for purposes of man-
agement becomes relevant only in terms of uses to which it is put.
Thus, a particular supply—a lake, an aquifer, or stream segment-
can be appraised in terms of use criteria. Therefore, we must look
into the properties demanded by particular uses as the criteria for
analyzing a particular supply.
Water Demands Quality Differentiated
Different uses of water require different properties of water and
vary in their toleration of particular properties (Timmons and Dou-
gal, 1968). For example, living cells may require the presence of cer-
tain minerals in water, whereas battery cells may not tolerate the
same minerals. Even organisms vary in their mineral requirements
and toleration of minerals. Quality of water must necessarily be
viewed in terms of a particular use if quality is to be manageable.
Different qualities are required (or tolerated) for animal consumption,
navigation, power, irrigation, food processing, air conditioning, rec-
reation, and manufacturing. Even within each of these major cate-
gories, demands are specialized. Beer, aluminum, paper, and syn-
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380 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
thetic fiber production each possesses important quality differentia-
tions.
Water quality suited for one use may be absolutely unsuited for
another use. Thus, it appears there is little, if any, relevancy for a
universal water quality standard. Instead, quality standards must be
developed in relation to specific uses to be made of particular water
supplies at particular points or periods of time in the process of sat-
isfying specific human wants. Such differentiations will likely ex-
tend to segments of the same water course, be it a stream, lake, or
aquifer. In other words, the quality mix of a particular water supply
must be analyzed in terms of uses to which it is put (Timmons,
1967).
Gearing Supply Qualities to Demand Qualities
Strategic to analyzing agriculture's role in water quality man-
agement is the identification of uses made or to be made of water
affected by agricultural uses. Also strategic is the determination of
water qualities required or tolerated by these uses. Only in this man-
ner may agriculture's contributions to water quality changes be de-
termined and evaluated in a relevant manner.
In recent years many projections of aggregate water demands
have been made. Projections for future water demands are basic
and necessary in providing essential elements of a normative and
predictive framework for planning and carrying out water policy.
But, in the future, these projections should not be considered as aggre-
gates. On the contrary, they must be disaggregated into segmented
differentiations derived from relevant estimators (Ackerman and Lof,
1959). Included as estimators by uses are qualities by amounts of
water demanded. Also included are the spatial and temporal occur-
rences of quality-linked supplies available for serving quality-linked
amounts to the estimated demands. Finally, the estimator of costs is
involved in terms of least cost alternatives for gearing (bringing or
keeping) supply qualities to demand qualities.
In regard to demand estimators, one further point should be
considered. This involves a more refined differentiation into direct
and derived components. Such a differentiation becomes important
in systems analysis involving regional accounts as well as in those
allocations which must be made through ordinal rather than cardinal-
oriented criteria. Thus, not only must we undertake to solve the com-
plex problem of determining the technical coefficients for water used
as an input but also the even more difficult one of specifying the de-
mand for water as a "final product," with all of the difficulties in-
herent in nonquantifiable parameters which must be ordered by or-
dinal criteria.
COSTS AND BENEFITS ASSOCIATED WITH WATER
QUALITY MANAGEMENT INCLUDING LEAST COST
METHODS TO MEET DEMAND QUALITIES
Continuing our reasoning that demand-oriented qualities set the
criteria for defining objectives (or standards) to be achieved or main-
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CHAPTER 27 / ECONOMIC ASPECTS / 381
tained in water supplies, we turn attention to the means for imple-
menting these objectives (standards). Products and services in these
uses provide the basis for approximating benefits and costs or utili-
ties and disutilities which cannot be quantified in the market.
Directions for Water Quality Management
Using demand-oriented qualities of water as criteria, three man-
agement directions are opened up for consideration. Direction I is
that the supply-oriented qualities can be lowered without adverse
effects on other uses than on the use lowering the quality. Under this
Direction, water is regarded as a legitimate dilution agent for the
wastes and fallouts of agricultural or other uses. Under this Direc-
tion, wastes from agricultural feedlots and fields with their chemi-
cals would use water as a dilution agent since this use would not in-
terfere with other uses. In other words, the benefit from agricul-
tural waste disposal would accrue to agricultural activities with no
costs to other uses. Therefore, net benefits would be maximized in
the process. Direction II involves the prevention of reduction in
water quality levels. Under this alternative, agricultural benefits
would have to be less than benefits accruing to other uses, costs con-
sidered. Of course, one important component of costs to agriculture
would be foregoing uses of certain technologies lowering water levels.
Pesticides and fertilizers might be examples. If such technologies
were foregone, the yields and production of food and fiber would
probably decline, which would adversely affect the public as con-
sumers through scarcities and higher prices of food and fiber. Direc-
tion III involves the raising of water quality uses where warranted
by higher productivity uses. Under this Direction agriculture would
be expected to curtail certain technologies which were being used in
order to upgrade water quality for other uses which are deemed more
productive in the use of higher water quality. As was the case under
Direction II above, costs to agriculture and to the consuming public
would have to be taken into account.
Differences between Directions II and III are essentially those
of prevention in II and reduction in III of certain uses associated with
agriculture. Under II the use of certain practices would be prevented
from taking place. Under III the use of certain practices would be
terminated. The major difference is in terms of implementation of
water quality changes where practices have already been capitalized
into the agricultural business (under III) and where practices have
not yet been capitalized into the agricultural business (under II).
QUALITY USE INTERRELATIONSHIPS
With these differences in mind, let us consider three major types
of interrelationships among water uses. These relationships are (A)
complementary, (B) neutral, and (C) competitive.
Under Relationship A (complementary) one use contributes to
the benefits or utilities of another use without experiencing costs or
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382 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
disutilities. An example would be use of a pesticide by one farmer
wherein the pesticide drift to the neighbor's crops would result in
additional benefits to the neighbor. Another example would be an
irrigator whose herbicides returned to the canal and benefited down-
stream uses of the water through preventing the clogging of the
canal with vegetative growth.
Under Relationship B (neutral) one use has no effect, neither
beneficial nor detrimental, on other uses. Other uses can tolerate or
are unaffected by quality changes left in the wake of previous uses.
Under Relationship C (competitive) one use exerts a detrimental
effect on other uses of water through lowering water quality required
by other uses. This Relationship is the one presenting the major
problems in water quality management. Here is where decisions
must be made in water management. Alternatives A and B do not re-
quire management decisions among uses since effects of wastes of
fallouts from one use are either complementary or neutral with other
uses. This would include Direction I discussed earlier, with Direc-
tions II and III falling into Alternative C.
Under Alternative C, water quality downward changes beneficial
for one use will adversely affect other uses. Conversely, water quality
upward changes will adversely affect uses effecting the change but
with beneficial effects on other uses. The major problem encom-
passes (1) the identification of all kinds of costs and benefits (utility
and disutility) associated with each use before and after the change
effected in water quality and (2) the assignment of weights in ordinal
or cardinal terms to each identified kind of cost and benefit (utility
and disutility).
Use and Technological Benefits and Costs
In the process of maximizing net benefits (net utilities) among
competing uses, benefits and costs of competing uses must be identi-
fied and estimated. At this point it is helpful to distinguish between
use benefits and costs and technological benefits and costs.
USE BENEFITS AND COSTS
Use benefits and costs are associated with products and services
produced or left unproduced by a use due to water quality changes.
This assumes that any change in cost due to water quality change
would be responsible for changes of production. Because of econo-
mies of scale or the fixed-variable cost mix, the effect is more likely
to be reflected in level of production and prices at which products
and services are made available. This in turn is responsive to price
elasticity, substitution, and production lags of products and services.
TECHNOLOGICAL BENEFITS AND COSTS
Technological benefits and costs refer to specific techniques
within a particular use of water. Assume that three techniques of
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CHAPTER 27 / ECONOMIC ASPECTS / 383
disposing or controlling cattle feedlot runoff are available. These are
(1) open field disposal, (2) playa lake disposal, and (3) natural evap-
orative system (Owens and Griffin, 1968). Further assume that each
technique is equally effective in producing the level of water quality
demanded by the highest use of water affected by the feedlot. Also,
assume that the cost effects on gains of cattle are affected only by
the relative costs of the techniques employed. According to a Texas
study, the investment cost per head of cattle for a 25,000-head feed-
lot would be $1.04, $0.83, and $1.49, respectively, for the three tech-
niques. Costs per head would annualize at $0.18, $0.13, and $0.14,
respectively. Thus, Technique 2 would represent the least-cost
method.
In another example, three alternative techniques are available
for disposal of liquid wastes from confined hogs. These are (1) haul-
ing and field spreading, (2) total lagooning of wastes, and (3) spread-
ing and hauling except for the period July 15 to October 15, when
the wastes would be lagooned as reported in an Illinois study (Kesler
and Hinton, 1966). Assume that the conditions imposed on the above
cattle feedlot techniques were imposed in the hog-lot study. For 500
hogs, the per 1,000 gallon annual cost of disposing of liquid manure
was $3.82, $1.78, and $4.37, respectively, for the above three tech-
niques which on a per hog basis is $0.69, $0.32, and $0.79, respec-
tively. On the basis of a 2,500-hog operation the results are $1.69,
$1.54, and $2.02, respectively, for the above techniques and $0.30,
$0.28, and $0.36, respectively, on a per hog basis. Thus, Technique
2 appears superior for both levels of operation, although the spread
of advantage lessens with size of operation (or scale).
The conditions assumed in the above two examples can be re-
laxed, and revised results obtained with additional information and
more complex analysis.
ASSIGNMENT OF BENEFITS AND COSTS ACCRUING
FROM WATER QUALITY CHANGES TO WATER USES
If agriculture's behavior in water quality management were as
simple as illustrated in the above examples under the assumptions
applied, agriculture's role in water quality management would be
easily interpreted and easily implemented. Unfortunately this is not
the case. In this section, attention is devoted to three particular prob-
lems which complicate the understanding and the implementation of
agriculture's role in water quality management. Although there are
other problems, the three selected for emphasis here are (1) exter-
nalities, (2) measurement, and (3) intervention.
The Problem of Externalities
The user of water may be in a position to keep the benefits from
use while shifting costs to other users by lowering water quality. If
he had to bear the shifted costs, he would be motivated to use the
water in a manner consistent with quality demanded by other uses.
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384 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
On the other hand, a user of water may be in such a position that if
he makes an outlay to maintain or improve water quality, he cannot
capture the benefits from his outlay which shift to other users. If he
could capture such benefits, he would be motivated to make outlays
which would maintain or improve the quality of the water after it
leaves his use. Such terms as "side effects," "spillover effects," or
"second party" effects have been applied to such shifts of costs and
benefits.
To the economist these conditions are termed externalities. The
rationale for this term is that the consequences of the actions are
external to the firm responsible for the actions. Externalities are
classified as economies and diseconomies. Beneficial effects are
called external economies and harmful effects are called external
diseconomies. Both have in common the phenomenon that the in-
cidences of the effects are shifted beyond the user that causes them.
The reason for this shift may be either of spatial or temporal origin
or both.
External economies (beneficial effects) become important in
water quality management if the economies affect the user's de-
cisions. If the user would use the water in the same way regardless
of whether or not he could capture the consequential economies,
there is no incentive effect on his decision. This was the case with
the irrigator using herbicides and the farmer using pesticides, men-
tioned earlier in this chapter. However, if as is more frequently the
case, the water user would not be able to capture external economies
in the form of improved water quality resulting from his outlays for
improving or maintaining water quality levels, external economies
become very important in water quality management.
Although the problem of external economies is important, ex-
ternal diseconomies appear far more important in agriculture's role
in water quality management. For example, wastes from chemical
fertilizers and pesticides and livestock wastes reaching into streams,
lakes, or aquifers may foreclose other uses entirely or make other
uses more expensive to undertake. Or they may endanger life and
health of human beings. Dr. Kneese concludes that "a society that
allows waste dischargers to neglect the offsite costs of waste disposal
will not only devote too few resources to the treatment of waste but
will also produce too much waste in view of the damage it causes"
(Kneese, 1964). Externalities are powerful concepts developed by
economists as a body of theory within welfare economics, with tools
of analysis having application to water quality. Starting with the
work of Pareto, published in 1909, and the work of A. C. Pigou, pub-
lished in 1920, many economists have devoted attention to develop-
ment of theory and tools which may now be transferred to water
quality analysis. In fact, Pigou's work was motivated in part by the
apparent effect of smoke from English factories upon the health of
English people and the cleanliness of their air environment.
The Problem of Measurement
Along with externalities, the problem of measurement is crucial
in water quality management. Traditionally, water has not been
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CHAPTER 27 / ECONOMIC ASPECTS / 385
allocated through the market sytem as have most other factors,
products, and services. Certainly, water quality is not reflected in
market values to an appreciable extent. Judging from the changing
size of national, state, municipal, and other governmental budgets,
an increasing share of the nation's resources is allocated through vot-
ing rather than through pricing processes. This creates problems in
resource management but these problems are not unfamiliar to the
resource economist and are not outside the science of economics.
Professor Gaffney has expressed relevant views on this problem
as follows: "Economics, contrary to common usage, begins with the
postulate that man is the measure of all things. Direct damage to
human health and happiness is more directly 'economic' therefore,
than damage to property, which is simply an intermediate means to
health and happiness . . . money is but one of many means to
ends, as well as a useful measure of value. . . . 'Economic damage'
therefore includes damage to human functions and pleasures. The
economist tries to weigh these direct effects of people in the same
balance with other costs and benefits. . . ." (Gaffney. 1965).
There exist four major alternatives for dealing with the
measurement problems in water quality measurement: (1) expand
and create market mechanisms for differential water pricing by
qualities or grades; (2) develop institutional pricing through syn-
thesized market prices and costs as weights assignable to water
grades or qualities; (3) legal action through legislation and/or
executive order with a public welfare basis; and (4) combinations
of the three.
Expand and Create Market Mechanisms for Differential
Water Pricing by Qualities or Grades
One alternative for dealing with measurement problems of
water quality would be to create market mechanisms wherein water
is priced by grades as a factor or as a product. Then water could
be metered and sold by private, government, or quasi-public en-
tities. Qualities of water could be conserved as a condition of sale
or repurchase and minimum quality levels could be warranted to
buyers and sellers.
Institutional Pricing
Another alternative is to assign prices to water by quality both
in terms of quality used and quality returned. There are two major
approaches to assigning relative weights to water qualities: value
productivities and opportunity costs.
VALUE PRODUCTIVITY
Through this approach various water qualities or grades of
water would be assigned values through a synthetic market of
shadow prices indicative of imputed values-through input-output
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386 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
analysis. Or, alternatively, water could be assigned weights by
grades of quality on the bases of relative contributions by uses to
state, regional, or national products of incomes through sector
accounting processes.
OPPORTUNITY COSTS
Another approach which is complementary to the value pro-
ductivity and income-generated ideas briefed above is based upon
opportunity costing analysis wherein the cost is suggested in the
form of shadow prices estimated from relinquished or diminished
options.
Four components of opportunity costing analysis are considered
here: (1) relinquished use options, (2) diminished use options,
(3) relinquished supply-source options, and (4) relinquished supply
treatment options. The first two components are very similar to
the case cited by Professor Gaffney wherein each wild duck in
Ventura County, California, used $560 worth of water valued in
terms of lima bean production sacrificed by water used in the duck
club (Gaffney, 1962).
Under (1) relinquished use options, the price of a particular
use may be imputed from the cost of the use option(s) relinquished
in the achievement of the particular use. For example, the denial
or forced cessation of use of water from a stream by an industrial
plant results in an annual loss of $100,000 worth of product as the
plant goes out of business in order to protect the annual production
of 25,000 trout. In this example, the production of trout becomes
the use allocated. Even though the price of trout may be difficult
to determine in the market, the price may be estimated from the cost
of the relinquished use forced out in the allocation process. In this
instance, the trout would have an imputed price of $4 each.
Continuing with the same example, let us illustrate (2) dimin-
ished use options by assuming that the 25,000 trout could be pro-
duced annually with a reduction in product by the industrial plant
of $50.000 annually. In this case, the use diminished amounting
to $50.000 would impute a price to the trout of $2 each.
Illustrating (3) relinquished supply source options, let us
assume that the industrial plant could either obtain its water from
another source or could release its effluent in another manner. Let
us further assume that this alternative source of water or effluent
disposal would cost the plant $50,000 more than the cost of the use
of the trout stream. In this case, the relinquishment of the use of the
stream by the plant in order for the 25,000 trout to be produced
would yield an imputed price to the trout of $2 each.
Illustrating (4) relinquished supply treatment options, let us
assume further that the industrial plant could treat its effluent in a
manner that would not affect adversely trout production in the
stream for a cost of $25,000 but the plant would remain in business
with a net product value of $75,000 rather than $100,000. In this
instance the price imputed to the trout would be $1 each.
Through these illustrations it would appear there are numerous
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CHAPTER 27 / ECONOMIC ASPECTS / 387
criteria and tools whereby the allocation of water qualities may be
evaluated. Also, it is obvious that present legal systems of water
allocation do not discern between use quality values and within use
quality levels of application. Consequently water becomes a free
resource to the extent of its availability as determined by existing
water rights with no incentive to economize by grades and qualities.
Legal Allocation and Restraint
Under this alternative water would be allocated by qualities
for specified uses and with specified return qualities. Also, wastes
and fallouts associated with livestock and crop productions would be
controlled by legislation or executive action. This would be carried
out under public health and welfare criteria just as cyclamates were
banned, DDT is in the process of being banned, and tobacco would
be banned if tobacco interests were less influential and subordinated
to the public interest.
Combinations
Most likely problems of measurement will involve each of the
three preceding approaches in some sort of combination. The pre-
cise application (and combination) remains to be decided upon.
The Problem of Intervention
Through the Water Quality Act of 1965 and the Clean Waters
Restoration Act of 1966, the federal government has intervened in
the identification, measurement, and implementation of water
quality levels. Most states have water quality control legislation such
as the Iowa Water Pollution Control Act of 1965.
Public intervention has come rapidly as revealed in state and
federal legislation. But there remains much to be accomplished in
moving from legislation to effective implementation of what the
legislation purports to do.
Under the Iowa Act "it is hereby declared to be the public
policy of this state to conserve the waters of the state and to protect,
maintain, and improve the quality thereof for public water supplies
for the propagation of wildlife, fish, and aquatic life, and for
domestic, agricultural, industrial, recreational, and other legitimate
(beneficial) uses; to provide that no waste be discharged into any
waters of the state without first being given the degree of treatment
necessary to protect the legitimate (beneficial) uses of such waters;
to provide for the prevention, abatement, and control of new, in-
creasing, potential, or existing pollution (Acts, 1965).
Shortly after enactment of the Iowa legislation, I wrote as fol-
lows: "In the implementation, administration, and future amending
of the Iowa Law, the concept 'degree of treatment' will necessarily
have to be determined. ... In the process, difficult decisions will
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388 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
be called for when uses compete with each other for waters of par-
ticular qualities. It remains doubtful that existing knowledge is
sufficient to make such decisions if they are to result in maximizing
the aggregate and variable components of satisfactions which are
demanded by our society from water" (Timmons, 1967).
Subsequent conflicts between the federal and state water pol-
lution control commissions concerning quality standards as well as
intrastate conflicts among interest groups emphasize the problems
encountered and the nature and magnitude of the remaining action
in public interventions.
TOWARD RESOLUTION OF WATER QUALITY MANAGEMENT
PROBLEMS ORIGINATING WITHIN AGRICULTURE
The first step toward meeting water quality management re-
lating to water use within agriculture is being taken through be-
coming aware of the importance of water quality problems. This
book is part of this step. The need for information and facts is
urgent and apparent as the basis for understanding water quality
problems and management solutions. There is a real danger that
action will move faster than our factual basis for action and public
understanding of the facts will accommodate. Thus, there is an
urgency for research and education to provide foundations on which
action may be formulated and implemented. Public pressure for
the action will likely continue to press for solutions to water quality
problems.
Because of the urgency for relevant information useful to
policy and action formulation, research efforts must be planned,
undertaken, and completed with both care and dispatch.
The guidelines for research and education are becoming in-
creasingly clear. Some of them are suggested in this chapter. The
need to recognize the quality heterogeneities of water from demand
and supply orientations is evident. The importance of demand
orientations and requirements is paramount in specifying quality
standards which vary among uses, spatially and temporally. Supply
qualities must be geared to qualities demanded by uses. Least-cost
methods are necessary in meeting demand qualities. In assigning
benefits and costs to water uses, the problems of externalities,
measurement, and intervention are crucial.
Economics with its legacy of methods, theory, and its corps of
resource economists is a necessary part of the multidisciplinary
approach in planning and in carrying out relevant research necessary
for education, legislation, and administration of water quality
management.
REFERENCES
Ackerman, E., and Lof, G. 1959. Technology in ivater development.
Baltimore: Johns Hopkins Press.
Acts, 1965. Sixty-first General Assembly, Regular Session, State of
Iowa, p. 436.
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CHAPTER 27 / ECONOMIC ASPECTS / 389
Gaffney, Mason. 1962. Comparison of market pricing and other
means of allocating water resources. In Water law and policy in
the southeast. Inst. of Law and Government, Univ. of Ga.
. 1965. Applying economic controls. Bull. Atomic Scientist,
p. 20.
Kesler, R. P., and Hinton, R. A. 1966. An economic evaluation of
liquid manure disposal from confinement finishing hogs. Bull.
722. Urbana: Univ. of 111.
Kneese, Allen V. 1964. The economics of regional water quality
management, p. 43. Baltimore: Johns Hopkins Press.
Owens, T. R., and Griffin, W. L. 1968. Economics of water pollution
control for cattle feedlot operations. Spec. Rept. 9. Tex. Tech.
College, Lubbock.
Timmons, John F. 1967. Economics of water quality. In Water pol-
lution control and abatement, ed. Ted L. Willrich and N. W.
Mines, p. 36. Ames: Iowa State Univ. Press.
Timmons, John F., and Dougal, M. D. 1968. Economics of water
quality management. Proc. Intern. Conf. Water Peace, vol. 6.
Wash., B.C.: USGPO.
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CHAPTER TWENTY-EIGHT,
ALLIANCE FOR ACTION
JOHN M. RADEMACHER
I HIS is the age of the environmental specialist. "Ecology," a
word heard only in scientific circles 5 years ago, is rapidly becoming
the "in" word of the militant generation.
The role of agriculture in clean water is vital to the Midwest
and to the nation. In the preceding chapters are discussions by ex-
perts of the problems which affect us all. It is hoped that our con-
ference reinforced our alliance for action. In this pollution problem
we must respond with the attitude of action and do a job of cleaning
up our rivers and streams.
We Americans are forever proclaiming that the only certainties
in man's existence are death and taxes. Massive evidence is accruing
in our "effluent" society that would add a third certainty—the problem
of waste and what to do about it. The disposal of animal and human
wastes is one of the foremost problems facing mankind, and the
problem proliferates while we deliberate and debate.
On the east coast of the United States a megalopolis stretches
from Boston southward to Washington. The 30 to 50 million people
crowded into this narrow corridor represent the most concentrated
mass of humanity in North America. The human wastes from this
teeming hive exude massive pollution loads, with the vividly de-
scribed degrading effects upon the Potomac, Delaware, Hudson, and
Charles rivers already legend (Fry, 1966).
Yet by comparison these cities are "small-town" in terms of gross
organic pollution when you consider the loads dumped into the Mis-
souri River. Organic loads equivalent to 80 to 100 million popula-
tion equivalents have been measured in the river at Omaha and at
Kansas City. Dissolved oxygen levels below Kansas City all the way
to St. Louis are at times below 4 mg/1 and on occasion have dropped
to 1.0 mg/1 or less (Lightfoot, 1968). This occurs not at low flow but
during a rising stage when rain washes the landscape—the country-
side as well as the cities—and floods into the mighty Missouri.
The answer as to the source of such loads does not rest in human
JOHN M. RADEMACHER is Regional Director, Missouri Basin Region,
FWPCA, Kansas City, Missouri.
390
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CHAPTER 28 / ALLIANCE FOR ACTION / 391
population figures because the Missouri basin has less than 8 million
people. But in terms of animal population we are really loaded—20
million cattle, 16 million hogs, and 7 million sheep. Put in terms of
population equivalents, we have close to 370 milhon as the potential
organic load at any one time. This then, in large part, is where the
organic source in the Missouri River is derived, and with the practice
of confined feeding of the animals on the increase (U.S. Dept. Inte-
rior, 1968), the percent of that potential getting to the stream will not
diminish.
No longer is pollution the vested onus of cities and industries—
the farmer has also reaped a piece of the action. The spectrum of
pollution problems has broadened and agriculture with its silt loads,
organic loads, salt loads, nutrient loads, pesticides, etc., is definitely
within the overall area of concern.
When 22 out of 36 reported fish kills in one state were identified
as being caused by direct agricultural farming and feeding wastes,
that concern is real (State of Kansas, 1967).
When an agricultural pesticide has become a ubiquitous part-
ner in the makeup of all flora and fauna from pole to pole and ocean
to ocean, the concern is not only real but takes on the menacing pro-
portions of the dreaded radioactive pollutants.1
As a result a new dimension has been added to the role of agri-
culture—a clean water responsibility. This is not to say agriculture
did not recognize the need for clean water in the past; it has always
claimed clean water as a right.2 But the agricultural industry now
has to look at its own operations and recognize it can cause pollution
and that it must prevent or minimize the potential of that po^ution.
In developing an alliance for action to control agricultural pollu-
tion let us recognize that each problem area must be approached
generally in similar fashion—that is, waste source identification, esti-
mate of effect, and control. However, the specific solutions to silt
pollution, salt pollution, pesticide pollution, and animal wastes do
not mutually satisfy each other, and this chapter could not do justice
in attempting to explore the many and differing requirements for all.
Where silt is basically a conservation and management program for
all of agriculture, the salt problem is almost exclusively relegated
to irrigation agriculture and the basic economic detriments to down-
stream users as the result of concentration and leaching. Pesticides
relate directly to policy decisions at the highest levels to formulate
and use particular products and toward research to find more effective
yet less toxic compounds as far as the environment is concerned.
Only with animal wastes do we have a pollutant which lends itself
to more classical solutions and involves the farmer and feeder di-
rectly on a day-to-day basis (Shuyler, 1969). For this reason let us
look at the animal waste problems and see how the various interests
and pieces fit together.
1. Conclusion based upon reports from many sources on DDT levels
throughout the world.
2. Historical premise—SCS, FFA, 4H, Grange all pushed for clean
water in past.
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392 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
THE TECHNICAL BASE
The acquiring of the technical information is the first needed
step—the full development of the technical base. This does not
mean that control actions should or will wait for the full develop-
ment of the technical base. Rather, it means that control efforts must
be intensified now, using the known information. Concurrently, the
technical base will be strengthened.
The technical base incorporates, among other items, a thorough
knowledge of the waste sources, the water uses, and the water quality
and quantity. Responsibility for use of these items of information
rests with the federal and state water pollution control agencies, al-
though the resources of other federal and state agencies and the in-
dustry normally provide significant inputs to this data bank system,
and this goes beyond the normal meaning of cooperation—it means
participation on the part of all parties.
THE INVENTORY
The development of an inventory noting animal production, con-
centration, and location is an essential element of the technical base
for the animal waste problem. There is no one best method of quan-
tifying and qualifying the problem. While each state is unique, there
are many elements of information common to all states. A combina-
tion of inventory systems is being used in the various states and there
is no reason to alter this. However, a system of state program ac-
countability and actual inventory evaluation through selected ran-
dom checks is needed. For instance, aerial photographs could be used
in selected basins in those states where control efforts have not be-
gun or where adequate progress is not being made. It also appears
that mandatory registration is not only highly desirable from the
standpoint of prevention but would basically fill the waste source in-
ventory needs.
Population equivalent values are continually based on the total
animal waste production with little regard for the fact that only part
of the waste actually enters surface water and groundwater. Bv us-
ing inventory data, together with sampling and other surveillance
techniques, the relative amount of pollution from animal wastes can
be determined.
RESEARCH-DEMONSTRATION-DEVELOPMENT
Although Harold Bernard from our research program in Wash-
ington will go into specific details, I do want to touch on this import-
ant area.
There are many gaps in our knowledge concerning the most effi-
cient and effective means of controlling pollution. This will require
that specific research and development needs be delineated in accord-
ance with the expected trends of the feedlot industry. Not only must
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CHAPTER 28 / ALLIANCE FOR ACTION / 393
this research answer the most pressing present problems but also
must simultaneously provide the foundation of long-range plans for
developing sufficient technology to control feedlot pollution 5, 10, or
25 years from now. It has been estimated that by the early 1970s,
approximately 2,500 large commercial feedlots in the United States
will supply 70% of the nation's finished cattle (U.S. Dept. Agricul-
ture, 1967). These lots will in all probability require treatment be-
yond or in excess of that currently being used.
Feedlot pollution runoff could be greatly reduced with a mini-
mum expenditure by using known information. A comprehensive
demonstration project encompassing optimum management tech-
niques to determine and illustrate the amount that pollution can be
reduced should be of high priority. Since past studies have usually
dealt with existing conditions, it is important to quantify and qualify
the feedlot runoff under optimum management practices. The in-
formation obtained should give impetus to the implementation of
sound management practices throughout the nation. Furthermore,
the information obtained will also serve as base-line data for further
research to develop treatment processes for the large lots.
REGULATIONS
Regulations are, in effect, the blueprints for the animal waste
control program. They act as a guide to planning, construction, and
enforcement. Regulations are needed to ensure the feedlot operator
that the measures he is taking will guarantee a reasonable tenure of
operation. It is necessary that the operator know the controls being
installed are adequate and that frequent changes will not be sought
by the official agency. Uniformity which concurrently allows for
flexibility must be built into the regulations.
The existing legislation pertaining to feedlot pollution control
should be thoroughly evaluated. Many of the basic concepts con-
tained in the regulations are sound; however, more attention should
be directed to management practices which would prevent the wastes
from entering surface water or groundwater.
Our laws must give due consideration to the location of feedlots.
Feedlots have generally been located without regard to the soil inven-
tory and associated topographical characteristics. It may be not
only desirable but also necessary to employ zoning regulations to
prevent the encroachment of the animal population into urban areas
and prevent the encroachment of the human population into the
feedlot areas.
Regulations should also provide for a continuing, comprehen-
sive animal inventory, state by state, drainage basin by drainage
basin, which would provide definitive data on the character and com-
position of agricultural effluents, points of discharge, and other perti-
nent information.
Mandatory registration, including an animal population and
concentration inventory, should be an integral part of feedlot regu-
lations. Most of the states that have enacted legislation do require
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394 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN V/ATER
some form of registration; however, regulations enacted by some of
the states do not require registration until pollution results. This
puts the burden of finding feedlot pollution on the state water pollu-
tion control commission. Furthermore, this is undesirable as the reg-
ulation makes no provision for such preventive measures as properly
locating new feedlots.
Model regulations and basic criteria need to be drafted and de-
veloped. These should be refined and applied by each state to fit its
particular need. Here again, a cooperative effort on the part of fed-
eral and state agencies, university specialists, and representatives
from the feeder groups could serve the cause of clean water by work-
ing together to develop these regulations and criteria.
MANAGEMENT SYSTEMS
A sound animal waste management program encompasses pre-
vention, reduction, treatment, and disposal of animal wastes. The
inauguration of this program cannot wait while all the data are col-
lected ard assembled. To wait for all the ans\vers before taking ac-
tion would squander time—time that we do not have. To wait may
mean the degradation of many waters beyond the point of recovery,
with accompanving health hazards of undefined proportions. Echo-
ing Aristotle: 'The ultimate end ... is not knowledge, but action.
To be half right on time may be more important than to obtain the
whole truth too late."
A much broader view of waste management will be dictated by
socioeconomic changes. While the return of the wastes to the land
may not be competitive with commercial fertilizers on an immediate
cror» production basis, it may be highly profitable in terms of public
welfare over both the short and long range to use these wastes to re-
claim marginal lands. We are losing approximately a million acres
of agricultural land each year as a result of urban growth, highway
construction, and other natural and man-made incursions into the
reserve of productive land CMoore, 1968). It is difficult to equate the
true worth to society for the reclamation of lands. Certainly it ex-
tends much bevond the yearly crop production.
To date, the kaleidoscope of alternatives to reduce animal waste
pollution has been hrnored more fullv in principle than in prac-
tice. The simplest and most economical method of controlling pollu-
tion resulting from feedlot runoff is to minimize the quantitv of run-
off by preventing outside surface water from entering the lot. The
majority of feedlot operators have not used techniques which mini-
mize the quantity and strength of runoff waste.
CONTROL-TREATMENT DEVICES
Once all the management factors have been used to minimize
the quantity and strength of the runoff waste, treatment may be
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CHAPTER 28 / ALLIANCE FOR ACTION / 395
necessary. The most logical place to treat or reduce the wastes is at
the source.
Treatment and disposal of animal wastes center largely on proc-
esses currently used for domestic and industrial waste treatment.
While investigations have shown that animal wastes are amenable
to most of these processes, the treatment results have usually been
unsuccessful because of a lack of understanding of the character-
istics of the wastes, the magnitude of the problem, and economic con-
straints currently imposed by society.3
The percent removal concept of municipal sewage treatment is
not applicable to the control of feedlot pollution. Cattle feedlot run-
off is a highly concentrated organic waste (Dague, 1969). The
strength may equal that of normal domestic sewage or may be 10,
100, 1,000 or more times greater. Feedlot runoff may still contain
after treatment as high pollutional parameters as domestic sewage
before treatment if percent removal is the only criterion used for
treatment. Therefore, a "residual" concept of waste treatment is pro-
posed. That is, acceptable treatment is that which reduces the pollu-
tion to a prescribed level or residual which would assure adequate
treatment.
No one treatment process or treatment system will be the solu-
tion for all animal production units. A variety of management and
treatment systems will have to be developed.
LOOKING TO THE FUTURE
Surveys reported by Colorado, California, and USDA during the
early growth of the commercial feedlot indicated that optimum feed-
lot capacity ranged between 10,000 and 20,000 head. Today 30,000-
head capacities are routine with 40,000- to 70,000-head lots becom-
ing more prominent in the Panhandle area of Texas (Owens and
Griffin, 1968). Thus it becomes apparent that growth is still a part
of this industry.
There does not appear to be an optimum size feedlot. In all
probability large-scale animal production facilities will increase and
the problems will grow unless action is taken now.
Finally, we must consider the effects of animal waste control on
the economy. We have made cost estimates of nationwide water pol-
lution control (U.S. Dept. Interior, 1968-69). Still, net profit is a key
guideline to feedlot operations. This is proper and must be recog-
nized. However, it must also be recognized that when public agencies
develop progressive programs to alleviate environmental contamina-
tion, the taxpayer usually pays the bill. An enlightened public has
shown in all fields of environmental contamination, including water
pollution control, that it is willing to pay, in dollars, the added costs
of maintaining a high quality environment rather than risk its de-
struction.4
3. Personal assessment of situation.
4. Based on observation and federal and state legislative action over
the past 14 years.
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396 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
Agriculture must accept waste treatment as a legitimate produc-
tion cost so that the natural resources of this country may be handed
to posterity undamaged and undestroyed. Agriculture must recog-
nize that the ultimate cost of pollution abatement will be carried by
the public.
If it is the public who must bear the cost, then agriculture must
have the courage to include waste treatment as a part of its produc-
tion costs.
REFERENCES
Dague, Richard R. 1969. Animal wastes—a major pollution prob-
lem. Second Compendium of Animal Waste Management,
June 1969.
Fry, Keith. 1966. Land runoff—a factor in Potomac basin pollution,
1966. Interstate Commission on the Potomac River Basin,
Wash., B.C.
Lightfoot, E. 1968. Waste utilization and conservation. Presented
at Joint Seminar, Univ. of Mo. and Mo. Pollution Board, Colum-
bia, 9 April 1968.
Moore, Joe G., Jr. 1968. Remarks before the Western Reg. Conf. of
Trout Unlimited, Denver, Colo., 27 Sept. 1968.
Owens, T. R., and Griffin, Wade L. 1968. Economics of water pollu-
tion control for cattle feedlot operations. Dept. Agr. Econ.,
Texas Tech. College, Lubbock.
Shuyler, Lynn R. 1969. Using feedlot waste—design for feedlot
waste management. Second Compendium of Animal Waste
Management, June 1969.
State of Kansas. 1967. Plan of implementation for water quality
control and pollution abatement, June 1967.
U.S. Dept. of Agriculture. 1967. Agriculture statistics—1967.
Wash., D.C.: USGPO.
U.S. Dept. of Interior. 1968. Pollution implications of animal wastes
—a forward oriented review. FWPCA, Robert S. Kerr Water Re-
search Center, Ada, Okla., July 1968.
U.S. Dept. of Interior. 1968-1969. Cost of clean water. FWPCA
Publ.
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CHAPTER TWENTY-NINE
ACCOMPLISHMENTS AND GOALS
HAROLD BERNARD
I HOUGH the Federal Water Pollution Control Administration
has conducted research on some facets of agricultural pollution for
many years, for all practical purposes impetus was not given to the
program until the Federal Water Pollution Control Act of 1966, as
amended, became law. The Act extended the research and develop-
ment capabilities of the FWPCA. Whereas the agency had conduct-
ed research through universities and nonprofit organizations, the
new law permitted us to participate financially with the particular in-
dustries producing the pollution problem to help them solve their
problem. One section of the law requires the FWPCA to demonstrate
new and novel techniques and systems for abating pollution from in-
dustrial sources. It enables us to join with a user and participate in
a program up to 70% of the total cost of a project, but not exceeding
$1 million.
In the short time the FWPCA has been given this authority, in-
dustrial research and demonstration projects totaling more than $100
million in grants have been initiated, with FWPCA contributing ap-
proximately $40 million. Of this impressive sum, agricultural pollu-
tion accounts for approximately $2 million.
In addition to this type of activity, the agency has a large pro-
gram with universities, municipalities, and nonprofit institutions to
conduct more fundamental studies. Approximately $2 million has
also been expended under this authority in the area of agricultural
pollution in fiscal years 1969 and 1970. Before expanding on these
accomplishments, the goals of the FWPCA should first be explained.
All leading authorities agree that due to our population and our pro-
ductivity, the quality of our environment has suffered tremendously.
Unless the situation is reversed, we will have created a "Mission Im-
possible" and in "ten seconds we will self-destruct."
The goal for the FWPCA is to develop and demonstrate an array
of management, prevention, treatment, and control techniques which
meet the water quality standards established by the 50 states. This
objective applies to the agricultural industry as well as the steel
HAROLD BERNARD is Chief, Agricultural and Marine Pollution Con-
trol Branch, Division of Applied Science and Technology, Office of
Research and Development, FWPCA.
397
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398 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
industry, paper and pulp manufacturers, food processors, mining,
oil refinery, etc.
What is a water quality standard? In the Clean Water Act of
1965, Congress required that each state establish criteria for each
interstate stream which will guarantee its utility as a water resource
for the purposes assigned to the particular stretch of stream. The
following water quality standards were established by the state of
Nebraska:
CLASS "A" WATER USE—DOMESTIC WATER SUPPLY
1. COLIFORM ORGANISMS—Coliform group and fecal coli-
form organisms shall not exceed a geometric mean 10,000
total or 2,000 fecal coliform bacteria per 100 ml, based on
at least 5 samples per 30-day period. No more than 20%
of samples shall exceed 20,000 total or 4,000 fecal coliform
bacteria.
2. TASTE & ODOR-PRODUCING SUBSTANCES—Concen-
tration of substances shall be less than that amount which
would degrade the water quality for the designated use.
Phenols concentration shall not exceed 0.001 mg/1.
3. SUSPENDED COLLOIDAL, OR SETTLEABLE SOLIDS—
None from wastewater sources which will permit objec-
tionable deposition or be deleterious for the designated
uses. In no case shall turbidity caused by wastewater im-
part more than a 10% increase in turbidity to the receiving
water.
4. TOXIC AND DELETERIOUS SUBSTANCES—None alone
or in combination with other substances or wastes in con-
centration of such nature so as to render the receiving water
unsafe or unsuitable for the designated use. Raw water
shall be of such quality that after treatment by coagula-
tion, filtration, and sedimentation, the water will meet Pub-
lic Health Drinking Water Standards. Radiological limits
shall be in accordance with the Radiological Health Reg-
ulations, State of Nebraska, 1st edition 1986, and as
amended in its latest edition.
5. TEMPERATURE—The temperature of the receiving water
shall not be increased by a total of more than 5° F from
May through October and not more than a total of 10° F
from November through April. Maximum rate of change
limited to 2° F per hour.
6. DISSOLVED OXYGEN—Greater than 4 mg/1 for a month-
ly mean. Greater than 3 mg/1 in any individual sample.
7. HYDROGEN ION—Hydrogen ion concentrations expressed
as pH shall be maintained between 6.5 & 9.0 with a maxi-
mum total change of 1.0 pH unit from the value in the
receiving stream.
8. TOTAL DISSOLVED SOLIDS—A point source discharge
shall not increase the total dissolved solids concentration
of a receiving water by more than 10% and in no case shall
the total dissolved solids of a stream exceed 600 mg/1.
9. RESIDUE OIL & FLOATING SUBSTANCES—No residue
attributable to wastewater or visible film of oil or globules
of grease shall be present.
-------
CHAPTER 29 / ACCOMPLISHMENTS AND GOALS / 399
10. AESTHETIC CONSIDERATIONS—No evidence of matter
that creates nuisance conditions or is offensive to the
senses of sight, touch, smell, or taste, including color.
CLASS "B" WATER USE—FULL BODY CONTACT SPORTS
1. COLIFORM ORGANISMS—Shall not exceed a geometric
mean of 200 fecal coliform per 100 ml based on at least
5 samples per 30-day period & shall not exceed 400/100 ml
in more than 10% of the samples.
2. TASTE & ODOR-PRODUCING SUBSTANCES—None in
amounts which would be sufficient to interfere with desig-
nated use.
3. SUSPENDED COLLOIDAL, OR SETTLEABLE SOLIDS—
Same as Class "A."
4. TOXIC AND DELETERIOUS SUBSTANCES—Same as
Class "A."
5. TEMPERATURE—Same as Class "A."
6. DISSOLVED OXYGEN—Same as Class "A."
7. HYDROGEN ION—Hydrogen ion concentrations expressed
as pH shall be maintained between 6.5 & 9.0.
8. TOTAL DISSOLVED SOLIDS—Same as Class "C."
9. RESIDUE OIL & FLOATING SUBSTANCES—Same as
Class "A."
10. AESTHETIC CONSIDERATIONS—Same as Class "A."
CLASS "C" WATER USES—AGRICULTURAL, PARTIAL BODY
CONTACT SPORTS, INDUSTRIAL, FISH & WILDLIFE GROWTH &
PROPAGATION
1. COLIFORM ORGANISMS—Same as Class "A."
2. TASTE & ODOR-PRODUCING SUBSTANCES—Same as
Class "A." Shall not contain concentrations of substances
which will render any undesirable taste to fish flesh, or in
any other way make such fish flesh inedible.
3. SUSPENDED COLLOIDAL, OR SETTLEABLE SOLIDS—
Same as Class "A."
4. TOXIC AND DELETERIOUS SUBSTANCES—Same as
Class "A." Plus ammonia nitrogen concentrations shall not
exceed 1.4 mg/1 in trout streams nor exceed 3.5 mg/1 in
warm-water streams where the pH in these streams does
not exceed a pH value of 8.3. If the pH of a stream ex-
ceeds 8.3, the undissociated ammonium hydroxide as ni-
trogen shall not exceed 0.1 mg/1 in trout streams nor ex-
ceed 0.25 mg/1 in warm-water streams.
5. TEMPERATURE—Trout Streams—Allowable change 5° F,
maximum limit 65° F. Warm Water Streams—Allowable
change 5° F May thru Oct., 10° F Nov. thru April; maxi-
mum limit 90° F; maximum rate of change limited to 2°
per hour. For Missouri River, from Gavins Point Dam to
Sioux City, Iowa, maximum temperature 85° F, allowable
change 4° F.
6. DISSOLVED OXYGEN—Oxygen-consuming waste shall not
lower the dissolved oxygen in the receiving stream lower
than 5 mg/1 in a warm-water stream and 6 mg/1 in a trout
stream.
-------
400 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
7. HYDROGEN ION—Same as Class "A."
8. TOTAL DISSOLVED SOLIDS—A point source discharge
shall not increase the total dissolved solids concentration
of a receiving water by more than 20%, this value shall
not exceed 100 mg/1, and in no case shall the total dis-
solved solids of a stream exceed 1,500 mg/1. For irriga-
tion use the SAR value and conductivity shall not be
greater than a C3-S2 class irrigation water as shown in
Figure 25 of Agricultural Handbook 60.
9. RESIDUE OIL & FLOATING SUBSTANCES—Same as
Class "A."
10. AESTHETIC CONSIDERATIONS—Same as Class "A."
INTERMITTENT STREAMS
1. COLIFORM ORGANISMS—Not to exceed 20,000 per 100
ml as a monthly average value; nor to exceed this value in
more than 20% of the samples tested in any one month.
2. TASTE & ODOR-PRODUCING SUBSTANCES—Not appli-
cable.
3. SUSPENDED COLLOIDAL, OR SETTLEABLE SOLIDS—
Suspended solids shall not exceed 30 mg/1.
4. TOXIC AND DELETERIOUS SUBSTANCES—Radiological
limits same as Class "A"—shall not be toxic to livestock or
terrestrial wildlife.
5. TEMPERATURE—[none given].
6. DISSOLVED OXYGEN—BOD shall not exceed 30 mg/1.
7. HYDROGEN ION—Same as Class "B."
8. TOTAL DISSOLVED SOLIDS—[none given].
9. RESIDUE OIL & FLOATING SUBSTANCES—Same as
Class "A."
10. AESTHETIC CONSIDERATIONS—Same as Class "A."
Source: State of Nebraska Water Pollution Control Council.
Notes: Wastewater shall not degrade the receiving waters below the
stated criteria. These criteria are applicable at flows greater than
the lowest flow for seven (7) consecutive days which can be expected
to occur at a frequency of once every ten years.
The method of water-sample collection, sample preservation, analysis,
and measurement to determine water quality and the accuracy of the
results shall be in accordance with the latest edition of Standard
Methods for the Examination of Water and Wastewater, or by ap-
propriate regulations or procedures approved by the Nebraska Water
Pollution Control Council or the Federal Water Pollution Control Ad-
ministration.
In making tests or analytical determinations of surface waters to de-
termine conformity or nonconformity with the above criteria, sam-
ples shall be collected in such a manner and at such locations, times,
and frequencies as approved by the Council. Every effort should be
made to make the samples representative of the receiving waters
after reasonable opportunity for dilution and mixture with the waste-
water.
For temperatures: Flows considered are for ice-free conditions.
-------
CHAPTER 29 / ACCOMPLISHMENTS AND GOALS / 401
Table 29.1 is an example of a schedule for implementing pollu-
tion abatement from municipalities in a stretch of river. This sched-
ule is an intimate part of every state's standards. Similar schedules
are being developed for industrial sources.
It has been estimated that municipalities and states (FWPCA,
1968) will expend some $10 billion in the next 5 to 10 years to col-
lect and treat wastes to the level necessary for effluents to meet the
particular standard set for the receiving body of water. Industry will
provide treatment facilities that will require similar expenditures.
However, this consignment of a significant but small fraction of re-
sources in this short time period is only a temporary expedient. This
is illustrated quite succinctly in Figure 29.1.
Up to 1930, when primary treatment was the main treatment
concept, BOD released to the streams increased with population
growth. The short-lived dip in BOD during the 1930s was due prin-
cipally to public works projects. The increase in the 1940s was
caused by the diversion of all funds to the war effort. The decrease
in the rate of rise during the 1950s is a result of an increase in con-
struction of secondary treatment plants, and the downward trend in
the 1960s is a reflection of a recognition on the part of the public for
all effluents to receive at least an equivalent to secondary treatment.
The parts of the curve shown after 1967 are projected on the basis
that all municipal wastes will receive secondary treatment by 1972,
The continued downward trend of the curve is illustrative of the fact
that a greater amount of BOD is removed from effluents by treat-
ment than is contributed by municipalities. Significant gains are
postulated. Our stream quality will be enhanced to the levels we en-
joyed in 1915. However, this euphoria is short lived, the null point
is reached in 1980.
At that time the waste load resulting from our projected increase
in population exceeds the removal capacity of the projected treat-
ment plants. The amount of wastes discharged to streams increases
until by the year 2000 we have violated our water resources to the
same extent in which we are now mired.
To preclude this projected return to our present morass, the na-
tion must develop new techniques and systems to increase the quan-
tity of pollutants removed from municipal waste streams.
Recall that this curve illustrates the effect of only municipal
wastes and readily degradable organic constituents (BOD) on our
streams. Add to this industrial sources and wastes that exhibit a
chemical oxygen demand plus wastes from agricultural activities and
you project the potential magnitude of the pollution problem that
faces the nation.
There is no attempt here to focus the agency's efforts on pollu-
tion from agricultural activities. There is only a desire to place the
pollution problem from this source of the nation's economy into a
proper perspective and to expend a proportional amount of our ener-
gies to minimize pollution from this source within a similar context
as that enjoyed by the remainder of the nation's economy.
A recent federal task force composed of seven cognizant Federal
agencies studied the problem of pollution from agricultural activities
-------
TABLE 29.1 Municipal sources of pollution to interstate streams of Nebraska.
.N
O
K)
BOD
Stream Community
North Fork Republican
River Haigler
South Fork Republican
River None
Republican River Benkelman
Stratton
Trenton
Culbertson
McCook
Indianola
Bartley
Cambridge
Holbrook
Arapahoe
Edison
Oxford
Orleans
Alma
Republican City
Naponee
Bloomington
Franklin
Riverton
Red Cloud
Guide Rock
Superior
Hardy
Arikaree River None
1960 Type of
County Population Treatment
Dundy
Dundy
Hitchcock
Hitchcock
Hitchcock
Red Willow
Red Willow
Red Willow
Furnas
Furnas
Furnas
Furnas
Furnas
Harlan
Harlan
Harlan
Franklin
Franklin
Franklin
Franklin
Webster
Webster
Nuckolls
Nuckolls
268
1,400
492
914
803
8,301
754
309
1,090
354
1,084
249
1,090
608
1,342
139
206
176
1,194
303
1,525
441
2,935
285
No Sewer
Secondary (Lagoon)
Secondary
Primary
Secondary (Lagoon)
Secondary
Primary
No Sewer
Secondary
Secondary
Primary
No Sewer
Secondary
Secondary (Lagoon)
Secondary & Chlorination
Secondary
No Sewer
No Sewer
Secondary (Lagoon)
No Sewer
Primary
Primary
Secondary
Secondary (Lagoon)
PE to
system
1,400
450
850
700
15,000
720
None
850
350
1,000
None
1,200
600
4,370
180
None
None
1,100
None
900
280
640
45
PE to
stream
100
500
4,000
300
260
110
600
1,000
45
Date of
Compliance
Jan. 1, 1972
Jan. 1, 1972
Jan. 1, 1972
Jan. 1, 1972
Jan. 1, 1972
Jan. 1, 1972
-------
TABLE 29.1 (continued)
BOD
Stream
Community
1960
County Population
Type of
Treatment
o
CJ
Beaver Creek Danbury Red Willow 185
Lebanon Red Willow 143
Wilsonville Furnas 289
Hendley Furnas 79
Beaver City Furnas 818
Stamford Harlan 220
Sappa Creek None
Prairie Dog Creek None
Little Blue River Campbell Franklin 424
Bladen Webster 322
Ayr Adams 111
Deweese Clay 100
Oak Nuckolls 125
Hebron Thayer 1,920
No Sewer
No Sewer
No Sewer
No Sewer
Secondary (Lagoon)
No Sewer
Primary
Secondary (Lagoon)
Secondary (Lagoon)
No Sewer
No Sewer
Primary
PE to PE to Date of
system stream Compliance
Frenchman River . . ,
. . . Imperial
Wauneta
Hamlet
Palisade
Culbertson
Chase
Chase
Hayes
Hayes
Hitchcock
1,423
794
113
544
803
Secondary
Secondary
No Sewer
Secondary
Secondary
(Lagoon)
(Lagoon)
(Lagoon)
1,300
700
500
700
160 Jan. 1, 1972
800
410 280 Jan. 1, 1972
320
111
1,900 1,200 Jan. 1, 1972
-------
404 / PART 6 / AGRICULTURE'S INVOLVEMENT IN POLLUTED AND CLEAN WATER
en
1
a.
en
tn
o
to
UJ
QL 5- 3000
o
z
D
2
5000
4000
O "
H2 g-
Q 3
2000
1000
v x
1900
1920 1940 1960
YEAR
1980
2000
2020
FIG. 29.1. Estimate of BOD discharges to U.S. streams from municipal
outfalls, 1900-2020.
and recommended programs for its prevention, control, and treat-
ment. Their recommendations for various areas of concern follow
(Office of Science and Technology, 1969):
The prevention and control of sediment may be accomplished
largely by the control of its source, i.e. minimizing soil erosion and
curbing sediment delivery from agricultural, range, and forest lands.
To accomplish the control of plant nutrients, emphasis should
be on research and action programs on behavior and fate of applied
nitrogen, phosphorus, and other nutrients; minimizing runoff and
percolation of nutrients by using them more effectively; controlling,
treating, or removing excess plant nutrient from surface or sub-sur-
face drainage to maintain the desired quality of receiving waters;
effects of nutrients on algae and noxious water plants; use of har-
vested algae and other water plants.
A research and action program for controlling animal wastes
involves minimizing pollution by improved use of existing technology
as well as by developing new and improved animal management
methods and facility design; waste treatment and disposal methods;
and methods for converting wastes to useful products. It also in-
volves minimizing pollution through assisting in the establishment
and enforcement of standards and providing criteria for land use
planning.
Pollution from irrigation return flows can be reduced by pro-
grams designed for decreasing salt concentration of the irrigation
supply source; improving irrigation and drainage practices to mini-
mize the effects of salts and minerals on soils and return-water
quality: treating or disposing of salts and minerals in return flows;
-------
CHAPTER 29 / ACCOMPLISHMENTS AND GOALS / 405
improving plant tolerance and utilization of salts and minerals.
Intensive cooperative studies are required to more fully eval-
uate the impact of pesticides on the environment such as: evaluating
the nature, extent and impact of pesticides in the ecosystem; reduc-
ing the amount of hazardous pesticides in the environment; treat-
ing, controlling, or removing pesticides from soil, air, and receiving
waters; disposing of pesticide wastes, including used pesticide con-
tainers, in a manner least detrimental to the environment, and as-
sisting state regulatory agencies in the establishment of uniform
effective pesticide regulatory programs.
In light of these recommendations and our own forecasts on the
total pollution problem confronting the nation, the FWPCA embarked
on a program to simultaneously develop techniques and systems for
controlling and treating pollution from agricultural activities, using
existing technology, and to obtain the necessary information and
technology that will, in the future, maximize pollution abatement and
minimize costs.
As we are by all standards a young organization in this battle to
save our environment, and as projects usually run 3 to 4 years, there
are not many significant results that can be reported. Let me in-
stead indicate our expenditures for the 2-year period (fiscal years
1969 and 1970), future funding prospects, and the need for addi-
tional knowledge and demonstrations of control and treatment
methods.
In fiscal years 1969 and 1970 we expended over S4 million in
research and demonstrations involving pollution abatement from
pesticides, nutrient runoff, irrigation return flows, and concentrated
animal feeding operations. Costs have been about equally distrib-
uted. It is expected that this level of funding will be somewhat in-
creased in future years. In addition to this direct involvement we are
also able to extrapolate from research, development, and demonstra-
tion projects in other areas of the total agency program. Notable ex-
amples of this are the use of the aeration ditch for pig feeding waste
which was initially developed for municipal pollution treatment, ac-
tivated sludge for animal feeding runoff, and the movement of ni-
trates in the vadose zone and in aquifers. It is estimated that at least
a similar dollar volume of associated research and development is
being conducted in the other segments of our program (Fig. 29.2)
that can be utilized. Though this is an impressive start, there still is
a long road to travel. We need to develop and demonstrate viable and
effective means for controlling and treating pollution from all facets
of the agricultural economy to match the similar efforts expended
for municipal and industrial pollution abatement. I would encour-
age you to actively use the numerous avenues available in the
FWPCA to enable us to help you develop the necessary technology to
help your industry.
In summary, products from the agricultural industry are a nec-
essary and vital part of the nation's overall economy. Agricultural
activities also are a source of pollution. The public is demanding
that our past practices that have violated our environment be stopped
-------
RESEARCH,
DEVELOPMENT
AND
DEMONSTRATION
PROGRAM
11 1 12 | 13 U 1
?P
KJ
°S
21 •
n
(D
**» ui to
_ (0 1-"
£s i
OO- Q
-I*
<£- 5
•< CD «d
-a < K
n« £
Hjans
opment, and demonstration program struc
A, Oct. 17, 1968.)
MUNICIPAL-
POLLUTION
CONTROL
TECHNOLOGY
1101
Sewered
Viaates
.1102
Combined
3e«er
Discharges
1103
Storm Seyer
Discharges
1104
Non-Sewered
Run-off
1105
h on-Sewered
Municipal
Wastes
1106
Joint
(Mun./Ind.)
Wastes
INDUSTRIAL-
POLLUTION
CONTROL
TECHNOLOGY
1201
Metal and Metal
Products
1202
Chemicals and
Allied Products
1203
Power Production
1204
Paper and Allied
Products
1205
Petroleum and
Coal Products
1206
Food and
Kindred
Products
1207
Machinery and
Transportation
Equipment
1208
Stone, Clay and
Glass Products
1209
Textile Mill
Products
1210
Lumber and Wood
Products
1211
Rubber and
Plastic
1212
Miscellaneous
Industrial
Sources
AGRICULTURAL-
POLLUTION
CONTROL
TECHNOLOGY
1301
Forestry and
Loraiiyj
1302
Kuril Eun-of:'
13C3
Irrigation
He turn Flows
1304
Animal Feed
Lots
1305
Non-Sewered
Kural Wastes
MINING-
POLLUTION
CONTROL
TECHNOLOGY
1403
Mine
Drainage
1402
Oil
Production
U03
Oil Ghnle
1404
Other
Mining
Sources
1405
Phosphate
Mining
15
OTHEX-SOllRCEo-
OF- POLLUTION
CCN'TKOL
TECHNOLOGY
1501
Recreational
1502
Boat and
Ship
1503
Construction
Projects
150/V
Impoundment-s
1505
Salt Water
Intrusion
1506
Natural
Pollution
1507
Dredging and
Landfill
1508
Oil Pollution
lo
WATER
QUALITY
CONTROL
TECHNOLOGY
1601
Fu troph ion t i on
1602
Hiysical-Chf-mical
Ident.ii'ica* ion of
Pollutants
1603
Biological
Identif i ca t ion
oT Pollutants
1604
Source c.'.'
Pollutant.-,
1605
Fate of Pollutants
in Surface Waters
1606
Fate of Pollutants
in Ground Waters
1607
Fate of Pollutants
in Coastal Waters
1608
Water Quality
Control
1609
Water Resources
Planning and
Resources Data
1610
Cold Climate
Research
1613
Thermal
Pollution
17 I
WASTE TREAT-
MENT & ULTI-
MATE DISPOSAL
TECHNOLOGY
1701
Dissolved
Nutrient
Removal
1702
Dissolved
Refractory
Orgtr.3 cs
Removal
1703
Suspended and
Colloidal
Solids
Removal
1704
Dissolved
Inorganics
Removal
1705
Dissolved
Biodegradable
Organics
Removal
1706
Microorganisms
Removal
1707
Ultimate
Disposal
1708
Waste Water
Renovation
and Re-use
1709
General Waste
Treatment
Technology
18 I
WATER
QUALITY
REQUIREMENTS
PdvSKARCH
1801
Municipal Uses
1802
Industrial Use
1803
Agricultural
User,
1304
Recreational
Uses
1805
Fish and Other
Aquatic Life
1806
Other Single
Uses
1807
Multiple Uses
-------
CHAPTER 29 / ACCOMPLISHMENTS AND GOALS / 407
and has indicated a willingness to pay for a clean environment. It
is in the best interests of the agricultural industry to help develop
and demonstrate its own cures. We would be pleased to help in any
of the many ways we can.
REFERENCES
Federal Water Pollution Control Administration. 1968. Cost of clean
water, vol. 2.
Office of Science and Technology. 1969. Control of agriculture—
related pollution, a report to the President.
-------
INDEX
Accelerated erosion, 35
Acrolein, 202, 206
Aerated lagoons for treatment of
manure, 261
Aerobic environments, effects of
on manure, 259-60
Agricultural pollution. See also
Animal waste problem, fac-
tors in controlling
complexity of problem, 391
control of, 391
federal recommendations con-
cerning, 401, 404—5
FWPCA program concerning,
405
Agricultural practices to reduce
pollution, 69-70
Agricultural sources of nitrogen in
water, 99-120
Agricultural wastes, regulation of
chemical fertilizers, 373-74
feedlot wastes, 369-70
pesticides, 371-73
silt, 374-75
Aldrin
biological epoxidation of, 172
metabolism of, 172-73
Algae growth, 348
Amine-sugar condensation, 138-39
Amino acids, 134-35
polymerization of quinones with,
137-38
Amino sugars, 135
Amitrole, 202. 206
Ammonium nitrogen, 102
Anaerobic environment, effect of
on manure, 257-59
Anaerobic lagoons for pretreat-
ment of manure, 262
Animal waste management, 241,
286-95. See also Animal
waste problem, factors in con-
trolling
Animal waste problem
effect of automation on, xxi-xxii
factors in controlling
control-treatment devices,
394-95
economic considerations, 395
growth trend in feedlot indus-
try, 395
inventory, 392
management programs, 394
regulation, 393-94
research, demonstration, de-
velopment, 392-93
technical base, 392
and growth of food industry,
xix—xx
Animal wastes. See also Livestock
wastes
biochemical oxygen demand
(BOD) of, 232
chemical oxygen demand (COD)
of, 232
infectious agents in, 233
nitrogen and phosphorus in, 233
pollution characteristics of, 231
Applied pest control, advantages
and disadvantages of
biological control, 211-12, 220,
221
chemical control, 213-14
cultural control, 213
insect sterilization, 213
mechanical controls, 213
physical control, 213
Aquatic community
composition of, 63
factors affecting
agricultural fertilizers and
animal wastes, 337-39
environmental pollution, 332
eroded soil, 335
irrigation return water, 335
pesticides, 332-35
functions within, 332-33
modus vivendi of, 63
Atkinson v. Herington Cattle Com-
pany, 366-67
Atmospheric precipitation, as a
source of nitrogen, 96-97
Bacterial diseases, role of water in
transmission of, 269-74
anthrax, 271
brucellosis, 272
409
-------
410 / INDEX
Bacterial diseases (cont.)
colibacillosis, 273-74
erysipelas, 272-73
leptospirosis, 276
salmonellosis, 269-70
tetanus, 273
tuberculosis, 273
rularemia, 271-72
Biochemical and chemical deg-
radation, as a source of her-
bicide dissipation, 200
Biochemical oxygen demand, 232
BOD. See Biochemical oxygen de-
mand
BOD removal, 347
Carbamates, 169, 177-78
Carbaryl, metabolism of, 177-78
Carbonaceous BOD, 345
Cation exchange, 25
Chemical inhibitors, 152
Chemical oxygen demand, 232
Chemical reactions of sediments
interaction of colloids with neu-
tral compounds, 25-26
ion exchange, 24-25
Chlorinated hydrocarbon insecti-
cides, 169. See also Aldrin;
DDT; Toxaphene
permissible levels of, 225
survey of in drainage basins,
185-87
Clay colloids
definition of, 23
physicochemical character of,
23-24
structure of, 23
Clav mineralogy of sediment, 22
COD. See Chemical oxygen de-
mand
Condensed phosphates, 77, 80
Conservacy District Bill, 48
Contour planting, 41
Contour strip-cropning, 41
Copper sulfate, 202
Cotton culture, and pesticides, 219
Dalapon. 203-4, 206
DDA, 170-71
DDD, 170-71
effect on aquatic community,
333
DDE, 169-71, 185-87
DDT. See also Chlorinated hydro-
carbon insecticides, survey of
in drainage basins
effect of on aquatic community,
334
environmental contamination
by, 184-85
metabolism studies of, 169-70
metabolites of, 167-71
Deforestation, as a source of nitro-
gen, 118
Denitrification, 28
Dieldrin, metabolism of, 172-73
Diquat, 206
Disease transmission
history of theory concerning,
265
role of water in, 269 (see also
Bacterial diseases; Fungal
diseases; Parasitic diseases;
Rickettsial diseases; Viral
diseases)
Dredging, as a source of nitrogen,
118, 120
Economics of soil conservation, 50,
56, 57
Enhanced plant nutrient levels
relative contribution of each
source, 67-68
sources of, 67
Erosion
acceleration of, 35, 52
control of, 35^3
geologic, 35
and nutrient loss, 144—45 (see
also Nitrogen in soils; Ni-
trogen in water; Phosphor-
us)
process of, 35—43
and water degradation, 144
Erosion by water
control and prevention of, 36-43
slope factor in, 36
soil factor in, 36
Erosion control practices, 46—47
criticism of, 47
Erosion problem, action on, 47, 48,
50
Eutrophication
agricultural factors in, 320-28
animal wastes, 321-22
cropping practices, 322-23
crop rotation, 322
fertilizer practices, 322-23
soil management, 322
biological changes associated
with, 337
control of, 314-15
effects of, 314
relation of agricultural drainage
to, 337
relation of animal wastes to, 339
relation of nitroeen and phos-
phorus to, 337
relation of weight of fish popu-
lation to. 337
role of phosphorus in, 160
-------
Eutrophication from agricultural
drainage, estimates of, 323-
28
for Lake Mendota, Wisconsin,
324-27
for surface waters, Wisconsin
327
for U.S. water supplies, 327-28
FDA, and pollution control, 371-
72
Federal Water Pollution Control
Administration
accomplishments of, 397
dispute of with Iowa Pollution
Control Commission, 368
goal of, 397
Feedlots, as a source of nitrogen,
111
Fertilizer
application methods and rates,
162-63
use, 142-44, 154
in comparison with nutrient
removal, 143-44
in the north-central spates,
142-43
Fertilizer phosphorus
distribution patterns in soil, 87-
99
inorganic phosphorus, 87-90
organic phosphorus, 90-91
reactions of with soils at high
concentrations, 80
reactions of with soils at low
concentrations, 81, 83
Fungal diseases
deep systemic mycoses, 277
his'oplasmosis, 277
ringworm, 277
FWPCA. See Federal Water Pollu-
tion Control Administration
Geological sources of nitrogen, 97-
98
Geologic phosphorus cycle, 75
analysis of, 75
problems in, 75
Geomorphology, 7-8
Geo-organic nitrogen, 95
Gross erosion, 4
Groundwater pollution
by agriculture-related products,
factors involved in, 303
control of, hydrogeologic factors
in, 312
by fertilizer nutrients, 308
by organic wastes, 309-10
by pesticides, 309
Gully erosion, 10—11
INDEX / 411
Gully growth rates, 10-11
Herbicides
in irrigation water, 204-6
concentrations of, 204-6
effects on crops, 204-6
in water, 196-200
dissipation of, 200-204
means of entry
control of aquatic weeds
197-98
control of ditchbank weeds
199
control of floating weeds,
199
surface runoff, 199
permissible levels of, 224
use of in aquatic and bank weed
control, 194-96
use of in north-central states,
195-96
use of in southeastern states,
195-96
use of in western states, 195
HEW, and pollution control, 371-
72
Hillslope erosion, 7
Humus nitrogen, 136
Hydrogeologic settings
effects of in groundwater pollu-
tion, 307-8
pollution patterns in, 308
Hydrous oxides, 26
Industrial sources of pesticidal
water pollution, 188-89
Industrial waste, as a source of ni-
trogen, 116-17
Infectious disease, 266-68
Inorganic phosphorus, 74, 87-90
Insecticidal pollution of water,
sources of, 169
Insecticides. See also specific
names
history of, 167-68
metabolism of, 169-78
Irrigation return water, effect of
on fish, 335
Kaolinite in sediment, 22-24
Lake Okeechobee water develop-
ment project, 159-60
Land use policy, means of estab-
lishing, 54
Langmuir equation, 81, 83
Legal regulations concerning wa-
ter pollution
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412 / INDEX
Legal regulations (cont.)
land-use controls, 375
private-law approach, 365-67
public regulation (see Pollution
control by public regula-
tion)
watershed authorities, 375
Livestock wastes
groundwater pollution by, 237-
38
infectious agents in, 233
surface water pollution by, 233-
37
Malathion, metabolism of, 175
176-77
Manure
aqueous treatment systems for,
260-63
evaluation of, 263
chemical characteristics of,
256-57
composition of, 244-45
composting, 289
dehydration of, 289
environmental factors affecting,
257-60
incineration of, 289
microorganisms in, 257
natural drying of, 289
Manure decomposition
factors affecting, 249, 251
in feedlots and confinement
areas, 245, 248
in soil, 248, 251
Manure disposal, effect of lagoon-
ing on, 69
Manure management system for
roofed confinement unit, 236
Methyl parathion, metabolism of,
175
MicroChannel erosion, 36
Mineralization of animal waste in
soil, consequences of, 251-53
Mineralogical composition of sedi-
ment, 22-26
Monrrnorillonite, 22-24
Municipal-industrial waste treat-
ment, 346-47
primary treatment, 346
secondary treatment, 346-47
tertiary treatment. 347
Municipal water pollution control
plants, 344
Natural erosion, 35
Natural pest control, 209-11
Natural sources of nitrogen, 117
NH3, fixation, 132-33, 137
NH,% 127-32
fixation by clay minerals, 131
natural fixation, 131-132
Nitrates
effect of transport on, 118
as factor in stream pollution,
345
in groundwater supplies, 107
location of concentrations, 108—
9, 115
movement of, 161-64
in pond water, 117—18
in water supplies, sources of,
150-51
in well water, 107, 110, 111
Nitrification, temperature for, 152
Nitrite, 133-34
Nitrogen cycle, 99, 125
Nitrogenous biochemicals, 134-35
Nitrogen reaction with sediment,
27-29
Nitrogen runoff from soil
ammonium nitrogen, 102
erosion, 116
explanation of, 103, 105
major factors in, 100
storm-water runoff, 116
tile drainage effluent, 105
urea nitrogen, 101-2
Nitrogen, "safe" application rate
for, 153-54
Nitrogen in soils
effect of soil cultivation on,
139-40
factors influencing availability
of, 127-28 (see also NH3;
NH/; NO,-)
factors in loss of, 147
inorganic forms of, 126-34
management of, 147, 151-54
movement of
lateral movement, 105-6
in tropical soils, 106-7
organic forms of, 134—39
Nitrogen sources
atmospheric precipitation, 96-97
geological sources, 97-98
Nitrogen in water
agricultural sources of, 99-120
chemistry of, 94
entry into water, 94
in irrigation return flow, 106
in lakes, 98-99
in water supply, 53
limits of, 107-8
sources of, 96
NOr, 127-31
and denitrification, 129-31
Nutrient level in streams, weather
factor in, 357, 360-61
Nutrient pollution of streams,
major source of, 345, 349
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INDEX / 413
Nutrients in Des Moines River,
sources of, 350-60
agricultural, 351-52, 357
domestic, 351, 357
industrial, 351, 354, 357
Nutrients, effects on water use,
347-48
Nutrient sources
for surface waters, 349-50
for water supplies in U.S., 327-
28
for waters in Wisconsin, 327
Nutrients transported in agricul-
tural drainage, control of,
315-20
ammonium, 317
inorganic nitrogen, 317, 320
inorganic nhcsphorus, 317, 320
nitrate, 3f7-19
organic nitrogen, 318, 320
organic phosphorus, 318, 320
Organic colloids, physicochemical
character of, 24
Organic nitrogen, 94-95
Organic phosphorus, 74, 90-91
Organophosphates, 169. See also
Malathion; Methyl parathion;
Parathion
permissible levels of in water,
225
Orthophosphate, 74, 76-77, 80
Oxidation ditch, for treatment of
manure, 261-62
Oxidation ponds, for treatment of
manure, 260—61
Oxidized zone in sediment, thick-
ness of, 26-27
Parasitic diseases, 277-79
ascariasis, 278-79
balantidiasis, 278
strongyloides, 279
taeniasis, 279
toxoplasmosis, 278
Parathion, metabolism of, 175-76
Pesticide metabolites, biological
effects of, 226
Pesticide pollution
chronic environmental, 184-85
con'rol of, 190-91
of water, 220
through accidents and care-
lessness, 189-90
Pesticide production, 183-84
Pesticide runoff
control of, 188
as source of water contamina-
tion, 187-88
Pesticides
effects of on aquatic commu-
nity, 332-35
alteration of composition of
community, 334
biological magnification, 333
destruction of aquatic insects,
334
development of resistance,
333
toxicity, 334
as industrial waste products,
permissible levels of, 225
problem of persistent, 334-35
in water
permissible levels of, 224
source of entry into, 189-90
Pesticide use, 183-84
dilemma over, 226-27
Pest management in farm produc-
tion programs
in corn, 218-19
in cotton, 216-17, 219
in food, 216
in fruit and vegetable, 216
in livestock, 216
in lumber, 217
in small grain, 218
in tobacco, 220
Phosphate fertilizer, movement of
in soil, 87-90
Phosphorus
capacity of soil to react with,
83-85
magnitude of various sources of,
146-47
reaction of with sediment, 29-
31
release of from sediment, 30-31
runoff source of, 146-47
in soils, 145-46
in surface water, 160—161
levels of, 64-67
methods of reducing, 69
present level of compared to
natural level, 65
relative agricultural and ur-
ban contributions to, 67-
68
role of agriculture in, 70
source of, 75-76
transferral of from soil to water,
146
Phosphorus biological cycle, 77
Phosphorus cycle in soil, 72—74
chemical cycle, 74
vertical cycle, 72-73
Plant nutrients
changes attributable to, 64
effects of enhanced levels of, 66
superabundance of in water, 63
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414 / INDEX
Pollutants relating to agriculture
behavior in ground, 305-7
distribution of, 304-5
Pollution control by public regula-
tion, 367-76
of agricultural wastes, 368 (see
also Agricultural wastes,
regulation of)
federal level of, 368, 371-73
local level of, 375
of municipal-industrial wastes,
368-69
state level of, 367-68, 369-71,
375
Pollution from municipalities,
control of, 401
Quality-differentiated water
demand for, 379
gearing supply and demand for,
380
supply of, 379
Quality theory of water, 378-79
Reduced zone in sediment, 27
Reservoir sedimentation
distribution of, 14
specific weight of, 14
trap efficiency, 13-14
Reservoir surveys, 11
Rickettsial diseases, 274
Riparian rights, 366
Runoff impoundment basins, 235-
36
Sediment
concentrations of in streams,
49, 51
harmful effects of, 3
oxidized zone in, 26-27
production of by precipitation,
26
Sedimentation
and nutrient loss, 144-45
and water degradation, 144
Sediment delivery ratio, 11, 12
Sediment in transport, 14-16
bed load, 15, 16
suspended load, 15, 17
wash load, 15, 16
Sediment yield
definition of, 35
information on, 11
regression equations concern-
ing, 12
from watersheds, 12
Sheet erosion, 5—10
empirical data on, 5-7
factors in, 5-6, 8
geological data on, 7-8
mathematical model for, 8-10
Sheet-rill erosion, 36
Silvex, 204-6
Slope modification for erosion con-
trol, 41-42
contour planting, 41
contour strip-cropping, 41
terracing, 41—42
Soil Conservation Service, 47-48
Soil conservation, strategy to at-
tract support for, 57—59
Soil cultivation, effect of on chem-
ical cycle, 74
Soil erosion
distinction between sediment
yield and, 35
steps in process of, 35
Soil and Water Conservation Re-
search Division, erosion
model of, 8
Soil wettability, factor of in ero-
sion control, 38
Sorption process, as a source of
herbicide dissipation, 200
Sources of nitrogen in water sup-
plies, 120. See also specific
sources
Storm water runoff, as a source of
nitrogen in water supplies,
116
Surface detention and retention of
water, relation of to erosion,
36-38
Surface mulch, 37-38
Suspended load samplings, 11
Synthetic ammonia, xx
Terracing. See Slope modification
for erosion control
Tillage methods for erosion control
clean tillage, 39
deep tiPage, 40
mulch tillage, 39, 40
postplanting tillage, 40
Toxaphene, metabolism of, 173-74
Turbidity, effects of on aquatic
community, 335-36
2,4-D, 195-201, 203-6
Universal rainfall erosion equa-
tion, 144
Universal soil loss equation, 5-6,
36, 48
Urban sewage, contribution of to
phosphorus level, 68, 70
Urea nitrogen, 101-2. See also Ni-
trogen runoff from soil
USDA, and pollution control, 371-
72
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INDEX / 415
Vegetable cover, 37
Vermiculite in sediment, 22-24
Viral diseases, 274-76
foot-and-mouth, 276
hog cholera, 276
Newcastle, 276
Volatilization, as a source of her-
bicide dissipation, 200, 202
Waste collection
system of dry, 286-87
system of wet, 287
Waste as a source of nitrogen
industrial, 116-17
rural
barnyard wastes, 113
feeds, 114
urban
domestic wastewater, 114-15
groundwater infiltration, 115
leaching and erosion, 116
storm water, 116
Waste storage, 287-88
Waste treatment
dry systems of, 289
of streams, 345
wet systems of, 289-95
Waste utilization and disposal, 295
Waterfowl as a source of nitrogen,
111
Water intake rates of soil, relation
of to erosion, 36-37
Water pollution, federal regulation
of, 339-40
Water pricing, methods of, 385-87
Water quality
public regulation of, 387-88
standards of Nebraska, 398-400
Water quality management, eco-
nomics of, 378
allocation of water, 385-87
differential pricing of water,
385-86
external diseconomies, 384
external economies, 384
gearing supply to demand quali-
ties, 380
least-cost considerations, 380-81
technological benefits and costs,
382-83
use benefits and costs, 382
Water transmission of disease. See
Disease transmission, role of
water in
Water use interrelationships, 381-
82
Weeds, use of herbicides to control
aquatic, 197-200
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