Water Pollution – Agricultural (1967)

Mr. W. A. Steggles,
Supervisor,
Water Quality Surveys Branch
Ontario Water Resources Commission

In management of our agriculture industry, we can either accelerate deterioration of quality in our natural waters or direct efforts to retard, and hopefully bring pollution to a standstill. We have this choice today. Impairment of ground and surface waters caused by polluted soil, misuse of pesticides and fertilizers, and inadequate handling and disposal of animal wastes, has been demonstrated here in Ontario and elsewhere. Popular recognition of these aspects and their possible extent has only recently developed and is growing. We know clearly that environmental pollution is not confined to the city dweller or urban-oriented industry. Further, we understand that for water pollution to occur from agricultural practices, the prelude is often misuse of land and soil and other resources. In the next few moments, I propose to highlight the existing effort that is being made in Ontario to control the following potential pollutants:

1. sediment pollution caused by erosion;
2. pesticide pollution of water;
3. dissolved solids pollution of water resulting from crop irrigation and soil fertilization; and finally
4. bacterial pollution and deoxygenation of natural water by mishandling of animal wastes.

Policy for Water Use in Ontario

Recently, the Ontario Water Resources Commission revised its objectives policy for water quality in the province, recognizing that increasing competition for water requires a new approach to the control of quality in our lakes and rivers. Environmental pollution may affect our health, but it also has one other basic legacy — it restricts or in some cases, makes impossible the use of water. One of the areas of water use that the OWRC recognizes as requiring protection from pollution is that of agricultural water use. Where water is used for farmstead water supplies, livestock and irrigation, whether from farm ponds, wells, or stream supplies, its quality must be protected for these possible uses. In this regard, the Commission’s concern extends beyond the rural and agricultural community. We have responsibility for ensuring for those who wish to use water for any beneficial use, that the quality be compatible with other needs including public and industrial water supplies, recreation, fish, aquatic life and wildlife. To accomplish this, the agriculture and other industries must actively plan and carry out measures to control pollution. The Commission is not being unrealistic or excessive in these requirements — rather it is asking people to be reasonable in their use of water allowing for its subsequent use by others. A more comprehensive review of this policy will be given by our General Manager in the program tomorrow.

In terms of pollution arising from erosion, pesticides, dissolved solids and animal wastes, this new policy means:

That in the case of erosion, it is not reasonable, nor is it of benefit to downstream communities to have to maintain systems for clearing ponds, reservoirs and harbors of eroded silt. It is expensive — we must eventually pay the price. We are told that the Mississippi River carries 0. 5 billion tons of sediment every year, while in Toronto Harbour, the Harbour Commission is required to dredge over 1000 cyds (900 tons of silt and debris each day at the outlet of the Don River to maintain the shipping channel. This, by the way, cannot all be laid at the feet of agriculture, although much could be done by land managers to improve the situation.

In the use of pesticides, it is most unreasonable and potentially a hazard to health to use and apply pesticides in such a way as to contaminate soil and water. As our waterways are inevitably used for other subsequent beneficial uses, the quality requirements for these uses predicate very restrictive controls on the use of chemical pesticides to avoid the type of long-lived contamination often associated with their use.

While crop irrigation will always result in return flows higher in dissolved solids than the applied water, there is little that can be done by the individual irrigator to correct this change in the water quality. Although not considered to be a problem in Ontario today, changes in water quality resulting from irrigation are almost impossible to control.

In the case of plant nutrients — nitrogen and phosphorus, that promote nuisance aquatic growths and contribute to other undesirable changes in surface waters, interference with several possible beneficial uses of water is now demanding that effective means be found to control the release of these materials to the environment. While there is reason to be mildly optimistic about chances for success in developing waste treatment systems that can remove nitrogen and particularly phosphorus from wastes, solution to the problems arising from agricultural land use will require a revolution in practice and technology.

Water pollution from animal wastes and feed lot run-off will receive special attention during the conference. Where the oxygen content of a receiving stream is depleted by drainage waters from livestock operations, possible interference with other beneficial uses of water can be prevented by the application of suitable waste handling and treatment technology. Adaptation of conventional biological waste treatment methods holds out promise for improved solutions to this difficult problem.

Ontario Program for Agricultural Pollution Control

1. Sedimentation Pollution by Erosion

In the soil conservation and land use program, Ontario’s conservation authorities have worked with the Department of Agriculture in a number of projects. These have included: demonstrations of improved land management practices applied to gully control, farm pond construction, reforestation and pasture improvement, land judging competitions, assistance to landowners to build grass waterways and farm drainage systems, and projects to control stream bank erosion.

In a recent report the conservation authorities have drawn attention to the serious problems associated with stream bank erosion. Where at one time, farmers were able to keep up with breaks along river banks and clear away channel obstructions, it is now apparent that much good farmland is being lost with undermining of bridges, buildings, roads, etc. This is attributed to unwise farming practices and developments along rivers.

Much stream bank erosion results from livestock grazing the grass and growth along stream banks which often break down under trampling to expose materials. Land managers are encouraged to consider fencing of stream banks with watering or cross-over places at points least subject to erosion. Plowing too close to a river bank will cause erosion, and buffer strips along the river banks should be maintained.

In some cases stream bank stabilization and additional protection is required. Authority officials point out that regardless of the procedures used, erosion control measures are not permanent and must be maintained.

Other methods of soil management and stream discharge control include:

a. Modifying soil properties by adding soil amendments that cause the soil to be less subject to slacking, detachment, and transport;

b. Employing tillage, planting and cultivating techniques to trap and hold rainfall for infiltration into the soil to reduce the amount of soil erosion and carry over of potential pollutants into a stream;

c. Modifying of field slopes to intercept and impound runoff to allow for deposition of sediment which might be otherwise suspended and washed away; and

d. The discouraging of overgrazing of range lands.

2. Pesticide Pollution

It is known that agricultural and domestic use of pesticides can result in low level surface water impairment from runoff. Further we know that these low levels can be concentrated in the food chain of aquatic organisms.

The Ontario Herbicide Committee made up of representatives of the Departments of Agriculture, Health and the Ontario Water Resources Commission maintains a watch on the application in Ontario of all types of herbicides. The Committee gives attention to the use of chemicals as herbicides on crops and as controls for aquatic nuisance. The effectiveness and selectivity of marketed chemicals are appraised and each year the Committee reviews as required its annual publication “Guide to Chemical Weed Control”. While the Federal Food and Drug Administration is concerned with residue levels in food and exposure to man, and the conditions under which products are marketed, the province through the Department of Health licenses commercial applicators and maintains a constant surveillance over the use of these chemicals. This work has
taken a great stride forward with the opening early in 1967 of the Ontario Pesticide Laboratory at the University of Guelph, where it is possible to perform complete analysis on a wide range of pesticides.

Other laboratory facilities are provided by the Ontario Water Resources Commission.

The O. W. R. C. is particularly concerned where materials are added to water for the control of aquatic pests, and a rigorous control program has been carried on with the co-operation of Lands and Forests since 1962.

3. Dissolved Solids Pollution and Soil Fertilization

While research studies on nutrient removal by algae, aquatic weed control methods, and taste and odor problems related to algae have been carried out for some time by the O. W. R. C. , the first concerted effort to examine the influence of land drainage on the waters of the Lower Great Lakes was commenced in 1964. Since that time the Commission has expanded this work and drainage basin studies have been carried on this past year to evaluate the influence of rural versus urban land drainage on the waters of the Great Lakes.

Whereas, the application of animal wastes as fertilizers presents a problem in managing the high nitrogen content of these wastes, chemical fertilizers provide man with another agricultural resource which, if well managed, can result in great benefit. If over-used these resources may lead to ground water and eventual surface water pollution.

Nitrogen applied to soil to minimize ground and surface water pollution, should be added in increments as needed rather than by applying a full season’s requirement in one application. The application of the major nitrogen needs should be delayed until the crop is able to actively absorb the applied nitrogen. Many agriculturalists make use of the services of the University of Guelph in determining optimum rates of fertilizer application for particular soils. This practice should be
encouraged.

4. Animal Wastes Management

When we learn that the farm animal population in Ontario produces an amount of waste equivalent to that from 45 million people, we realize the scale of the problem faced. An enterprise producing annually at a rate of 50,000 laying hens, or 5,000 market hogs, or 1,000 beef cattle, or 500 dairy cattle, generates a waste disposal problem comparable to a city of 10, 000 persons.

Over the past year, the Commission has been represented on the Committee on Utilization of Animal Wastes organized by the University of Guelph in co-operation with the Department of Agriculture. Its concern has been the handling and utilization of animal wastes in crop production to recover beneficial nutrient elements necessary for other forms of life. Where production and utilization of animal wastes can be integrated with crop and livestock production, best use is made of this fertilizer resource in our expanding agricultural economy. The application, however, of either animal wastes or supplemental chemical nitrogen in excess of crop nutrient needs, is believed to increase the possibility of water pollution. Therefore, great care is required in the application of fertilizers. In some cases, where water- carried waste systems are used and sufficient land area is not available, waste treatment methods are required before application to the land to avoid over fertilization and subsequent water pollution. In still other cases where it may be necessary to introduce the waste following treatment into a receiving water, special care must be taken to avoid interference with other possible water uses. While much of the O. W.R. C. research program in waste treatment has been oriented to municipal problems, this has been re-directed of late to answer many questions on the treatment of animal wastes before application to either soil or water. These are pressing problems for those operations where land is restricted in area and a high degree of waste treatment is required. In recent months the Department of Health has become active in the difficult problem of inadequate solid wastes management which has a
large bearing on the soil and water pollution problems.

Practical Guidelines for Avoiding Water Pollution from Application of Pesticides and Use of Animal Wastes

In this section, attention will be drawn to those known practical measures that farmers may use today to control pesticides and animal wastes. Certainly there are many areas of needed research; however, we cannot wait for the answers to all questions before applying ordinary common sense in correcting many obvious problems.

Pesticides

1. Select a pesticide that will not only destroy the target pest, but also be the least damaging to beneficial plants and animals, and be attenuated or degraded in a reasonably short time following destruction of the pest.
   
2. Apply the selected pesticide in the right place, at the right time, in the correct amount, and properly distributed to obtain the most effective results with the least hazard to beneficial life. Proper procedures include: using machines and techniques that most accurately direct and apply the pesticide; use of adhesives for maximum pesticide retention on the target area; application of minimum amounts at the right time for best control; use of spot applications in preference to broadcasting wherever practical; and use of weather forecasts to avoid rain removing foliar-applied pesticides and drift over water from strong winds. Ground applications should be used whenever practical to reduce the hazard to surface water pollution from aerial sprays.
   
3. Reduce drift from ground-driven applicators by using low spraying pressure and large droplet size, or by substituting granules for dust or sprays.
   
4. Use granular materials in preference to sprays whenever feasible. This avoids: probability of accidental back siphonage and spillage (of the pesticides or sprayer cleaning water) near a well or stream; fiber and plastic containers for granules and dusts do not present storage problems with corrosive liquids and are more easily destroyed than metal or glass containers.
   
5. Prevent back siphonage into a well or stream by supporting water hose or pipe above the maximum liquid surface in the sprayer tank to provide an air gap. Sprayer cleaning water should never be dumped near (several hundred feet) a well or stream.
   
6. Store pesticides in a building with an impervious floor and lower wall and control the access to it.
   
7. Read before using. An important factor in the safe use of pesticides is to follow labelled instructions.
   
8. Substitute biological control of pests for chemical control whenever
   possible.

Recommendations for Management of Animal Wastes to Avoid Water Pollution

1. In the Field

a. Field-spread wastes thinly so as not to exceed the rates for optimum nitrogen use.

b. Balance waste-borne plant nutrients with chemical fertilizers for optimum plant growth.

c. Incorporate solid wastes with the soil during or soon after spreading, taking account of the best time for fertilization in crop production.

d. Do not spread wastes on frozen or water saturated soils in areas where surface runoff will transport wastes into surface water.

2. In the Feed Lot

a. Locate feed lots where runoff into streams and soil infiltrate-borne nitrogen will have little effect on the future use of ground and surface waters.

b. Separate or divert runoff from areas of higher elevation, including roofs of buildings, from precipitation falling directly into the lot.

c. Construct solid waste storage areas within or adjacent to feed lots to control leaching of stored wastes by precipitation and run-off.

d. Construct necessary settling basins to intercept all feed lot run-off and retain all settleable solids. Field spread retained solids and supernatant seasonally.

3. In the Roofed Livestock Production Unit

Install proper waste handling system, taking into account the location of the unit and facilities for crop utilization or waste disposal, to avoid pollution of ground and surface waters.

The Future

There are two considerations respecting the future control of water pollution from agriculture: firstly, the state of our knowledge and the areas where further information is required; and secondly, the improvement of pollution control management programs. Included in the second part is the pursuit of needed knowledge and development of rational planning policies and programs to make the best use of the knowledge gained. In concluding this paper, I wish to draw attention to several areas of information requiring attention:

1. Improved understanding of the eutrophication or aging process in our lakes — world-wide attention is being devoted to this problem. In Canada, the Fisheries Research Board has launched a long-term study of this problem in the Great Lakes, while in Ontario, the O. W. R.C. has
   numerous inventory programs, surveys, and research projects in progress.
2. Increasingly better measures of the magnitude and effects of land erosion on our drainage basins is required — extension of the federal program for gauging sedimentation and erosion is desirable. The O.W. R.C. maintains a water quality monitoring program which provides an understanding of the suspended materials’ loads our streams carry.
3. More information is required on the fate of pesticides in irrigation water and the pollution potential of drainage waters contaminated by pesticides.
4. With increased research on the use of biological pest control methods, balanced use with improved chemical control methods should be encouraged.
5. Better information is required concerning:
   a. The quantities of water used in feet lot operations;
   b. The range of nutrient (nitrogen and phosphorus) concentrations and other characteristics of manures produced under specified conditions.
6. Development of waste treatment processes that would permit biological or other stabilization of animal wastes for crop utilization or disposal into receiving waters.
7. Determination of the loss of nutrient elements by soil erosion and the quantities and types of fertilizing materials that enter ground water with descending soil moisture.
8. The times and rates of maximum application of fertilizer that will not contaminate ground water.
9. Information is required to evaluate effects of varying quality water on soil in relation to the effects on water movement and plant growth.
10. There is need to:
    a. Delineate localized areas of polluted ground water;
    b. Properly close abandoned wells, improperly located and constructed wells and other openings into the ground water supply.
    c. Locate new wells such that zones of influence do not overlap known or suspected areas of polluted ground water.
11. Develop meaningful plans for water use encompassing needs for agriculture, fish, aquatic and wildlife, industrial and public water supplies and recreation that will integrate the efforts of existing programs organized to control environmental pollution.
12. Develop awareness in the individual land manager of the readily applicable measures he may use today to control soil and water pollution.

It is evident when dealing with large drainage systems that include the Great Lakes, piece-meal short term planning cannot ensure continuous availability of water with a high quality. The commonly accepted notion, that each of the Great Lakes is of such size and unlimited capacity for dilution of all sorts of drainage waters, has been proven wrong and must be rejected. Rather, the planning effort in relation to persistent slow decaying pollutants must become preventive-oriented large scale problems, once permitted to develop, become almost impractical to correct.

In the Commission’s water quality management program, drainage basin planning studies are underway to determine the magnitude of water quality change occurring in relation to water uses and needs. These include agriculture, land use, and other water uses. By utilizing the resources of modern computation methods in analysis of the complex system problems involved in water use, the Commission expects to define the limitations to be placed on each waste source introduced to the environment.

In rural areas where organized drainage and waste treatment systems are in use, this approach will also apply. While research is needed in many areas, we must depend upon the ordinary common sense of each farmer to take those steps possible today to keep the problems of water pollution within manageable limits.