Monitoring of Trends in Rural Water Quality in Southern Ontario

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The ECO has focused on water quality issues many times in recent years. In the 1997 ECO annual report, we found significant weak- nesses in several of the province’s monitoring programs and, as a result, shortcomings in the provincial ability to track and report on the state of our ecosystems. Since then, there have been some gains, but also some losses. Recommendations made in the Report of the Walkerton Commission of Inquiry suggest that new Ministry of Environment and Energy policies and programs are needed to ensure water protection at the watershed scale.

Too often streams, lakes and rivers are viewed as separate from the rest of the landscape. In reality, all human and natural activities on land are intrinsically connected to water. To live and work sustainably, Ontarians must know how activities on the land affect water resources. In this section, the ECO focuses on some of the principal water pollution concerns in rural southern Ontario, draws conclusions about the province’s ability to track water quality with the existing water monitoring frame- work, and identifies some necessary improvements.

Changes on the Rural Landscape

Some kinds of cropping and livestock management activities are intensifying in southern Ontario, raising concerns about their potential for affecting water quality. Livestock, poultry and hog producing facilities in Ontario have become larger and more intensive over the last two decades. Today, just 2 per cent of Ontario’s hog operations account for nearly one-quarter of the 5.6 million hogs produced each year. As the larger hog and cattle operations appear to achieve lower production costs, the intensification trend is likely to continue. In October 2001, the federal Commissioner of the Environment and Sustainable Development warned that farming practices in the Great Lakes and St. Lawrence River basin are having serious effects on the environment and that current practices are unsustainable. However, in southern Ontario the province currently lacks the monitoring system and, consequently, the data necessary for assessing the effects of these land use changes and making the needed strategic decisions.

Among the major concerns with intensive farming is the handling of manure. Enormous amounts of manure are produced in Ontario, and the risk to the environment is significant unless proper manure management practices are used. Between 1988 and 1998, 214 manure spills were documented in southwestern Ontario, resulting in 42 known fish kills. Most of those were from liquid manure applications and delivery to streams by way of field tile drainage systems. Although it is difficult to identify conditions leading to fish kills with routine monitoring programs, specialized sites with the capability of continuously monitoring for conditions lethal to fish have occasionally been established.

The highest per-unit-area production of manure in Canada, at 7,610 kilograms per hectare, is located in the Middle Maitland watershed, just south of Walkerton. The Upper Thames River and Grand River subwatersheds are also among the top five manure producing areas in the country, at over 5,000 kilograms per hectare. Provincial ministries, conservation authorities and some municipalities have at various times established programs to protect water quality by funding and promoting best manure management practices in all three of these areas. However, problems persist: Provincial Water Quality Objectives for E. coli, phosphorus and other parameters are frequently exceeded, and manure spills continue to occur.

The Nature of Water Quality Impairment

Microbiological Issues

Data reviewed by the ECO show that fecal coliforms are found in contaminated water from many rural sources. These include leakage from faulty septic systems or liquid manure storages, discharges from dairy milkhouses, and runoff from manure applied on wet or frozen soil. Infiltrated liquid manure, applied to some farm fields and carried away by drainage tiles, can also be a significant source. Water sampling results show that elevated levels of fecal coliform bacteria in streams and rivers and municipal drainage ditches can also be found downstream of cattle watering access points. In certain areas of southwestern Ontario, E. coli strain 0157:H7 is found in association with the bacteria from such sources. The tragedy in Walkerton in May 2000 underscored the need to be vigilant of such potential sources where drinking water sources are at risk. Other pathogenic bacteria such as Campylobacter and protozoa such as Cryptosporidium can also be transferred from animal herds to humans over broad areas – generally, wherever manure sources exist.

Beach closures, or warnings due to high E. coli counts along the Lake Huron shoreline, have been chronic occurrences during the summer tourist season. In the summer of 2001, the Huron County Health Unit reported 354 beach user-days (about 21 per cent of potential user-days) lost due to non-compliance with the recreational beach criterion of 100 E. coli per 100 millilitres for 18 Huron County shoreline beaches. Permanent signs warning that pollution levels are elevated for up to three days after a rainstorm are posted at 17 public beaches in Huron County. Numerous studies have attempted to categorize sources of the problem. Known sources include animal manure and faulty septic systems in rural areas. At beaches near urban areas, sewer overflows and lagoon discharges are sometimes implicated.

One major program, since discontinued, that attempted to deal directly with bacterial contamination of beaches from rural sources was the Clean Up Rural Beaches Program (CURB) initiated by MOEE and operated in conjunction with conservation authorities and health units between 1984 and 1996. Watershed and subwatershed sources of bacteria and phosphorus sources were mapped and strategies developed to cost-share with farmers and rural residents those practices that would effectively reduce pollutant sources. As a result of the program, downward trends in bacterial densities were documented in several tributary streams, and some inland beaches that had been closed due to high bacterial levels were re-opened. In 1999, the Ministry of Agriculture and Food established the $90 million Healthy Futures for Ontario Agriculture program, which includes rural water quality as one of its themes.

Nitrates, Human Health and Aquatic Life

Nitrogen in the form of nitrate is naturally occurring, but it is also introduced into the aquatic environment through wastewater discharges and through drainage water or runoff from fields where sludge, manure or fertilizers have been spread. Human consumption of water containing high concentrations of nitrate and nitrite poses a risk, particularly to pregnant women, nursing mothers and infants under six months of age. Of 1,292 farm wells tested in Ontario in 1992, 14 per cent exceeded the current Canadian Drinking Water Guideline for nitrate/nitrite.

Alarmingly, nitrate concentrations appear to be trending upward in surface waters in many of the river systems in agricultural areas of Ontario where sandy soils predominate. For example, nitrate concentrations in the Middle Maitland River rose from below 1.0 milligram per litre in the 1970s to about 4.5 milligrams per litre in 1994. As well, Lake Ontario nitrate concentrations steadily increased between 1968 and 1993. A possible explanation for these trends is the continued accumulation of inorganic nitrogen in agricultural soils. Over 70 per cent of soils on farm lands in the Great Lakes Basin and St. Lawrence lowlands are building up residual nitrogen. Between 1981 and 1986, nitrogen in drainage water from agricultural lands increased in concentration by at least 1 milligram per litre over almost all of southwestern Ontario. The ECO was unable to identify any more recent data to determine whether or not the situation has changed since 1986.

Aquatic life is also affected adversely by elevated nitrates. Across Canada, population sizes of 17 of 24 species of frogs and toads and 21 salamander species have declined in recent years. Recent Environment Canada studies show a high susceptibility of amphibians to nitrate toxicity, a likely link to these population declines. To protect amphibians, fish and reptiles, a new Canadian Water Quality Guideline (CWQG) of 3.0 milligrams per litre nitrate-N is currently under consideration. There is no equivalent provincial water quality objective for surface water. However, the current Ontario Drinking Water Standard is 10.0 milligrams per litre nitrate-N. The province has never had an ambient water quality objective for nitrate to protect aquatic life, so we have not been alerted to the problem – nor to its extent across our southern waters.

The proposed new CWQG for nitrate brings the degraded condition of the water quality of many southern Ontario rivers and streams into sharp focus. Measured against the guideline of 3.0 milligrams per litre, a high proportion of the river water in parts of the province dominated by sandy soils with agricultural land uses would be deemed unsuitable for sustaining amphibian life.


In many river systems in the southern part of the province, phosphorus concentrations exceed the Provincial Water Quality Objective (PWQO) for rivers and streams of 30 micrograms per litre. Higher phosphorus concentrations cause problem aquatic weed and algae growth, particularly in reservoirs where dead plant matter decays, sinks and uses up oxygen needed by aquatic fauna. Respiration at night by dense aquatic plant growths during summer can reduce oxygen to levels that can cause fish kills. Phosphorus concentrations have trended downward in river systems since the 1970s, when major sewage treatment plant upgrades began to be implemented, and as a result of detergent reformulation. However, recent evidence shows that the significant reductions of phosphorus in Lake Erie observed in the 1970s and 1980s have not continued. As a result, in 2000, open lake concentrations of phosphorus are still about three times higher than the target concentration. The sources are not definitively known because of the lack of surveillance and monitoring programs since 1994, but farming activities in Ontario are believed to be contributing 300 times more than municipal sources. In southwestern Ontario, concentrations of phosphorus in river water are generally much higher than the PWQO target of 30 micrograms per litre, and they tend to be higher in areas of more intensive cropping systems, higher livestock production densities and clay soils.

MOEE’s Monitoring Programs

MOEE states in its 2001/2002 Business Plan that it is committed to leadership in the monitoring and dissemination of environmental information and knowledge. MOEE has a number of monitoring strategies in place for Ontario’s lakes, rivers and streams, with a range of histories and purposes. These include:

  • Provincial Water Quality Monitoring Network
  • Enhanced Tributary Monitoring Program
  • Great Lakes Tributary Toxics Monitoring Program (including high-volume toxics sampling)
  • Great Lakes Water Intake Biomonitoring Program
  • Sport Fish Contaminant Monitoring Program
  • Streamflow Monitoring Network (funding partner with MNR)
  • Great Lakes Nearshore Monitoring and Assessment Program
  • Inland Lakes Monitoring Programs (Including Lake Partner Program)

Some of these programs have a high public profile, and their data are widely distributed by MOEE, e.g., the Lake Partner Program and the Sport Fish Contaminant Monitoring Program (incorporated in the biyearly Guide to Eating Ontario Sport Fish). Other programs have primary, although not exclusive, clients – for example, the Enhanced Tributary Monitoring Program that compiles information for the International Joint Commission. The Tributary Toxics Monitoring Program has been valuable in identifying contributing areas for priority organic pollutants such as PCBs. Core activities of the Nearshore Monitoring and Assessment Program are carried out on a lake-by-lake basis over a multi-year cycle. This program has been of particular value in measuring environmental indicators in nearshore areas of the Great Lakes and has been supportive of the Remedial Action Plans for Great Lakes Areas of Concern.

From the above list, there would appear to be a comprehensive list of monitoring activities under way that could address the status of a broad range of ecosystem components. The Provincial Water Quality Monitoring Network, however, has provided the main overview on water quality data for rivers and streams. Unfortunately, MOEE severely cut back on its monitoring network, from 730 stations in 1995 to 240 by 2000. Only six of these stations are located across the vast expanse of northern Ontario. The remainder represent less than six stations per major watershed in southern Ontario. The dismantling of the network seems clearly inconsistent with MOEE’s 2001/2002 Business Plan. The water bodies at the stations are sampled between 2-12 times per year for up to 39 parameters, mostly metals, nutrients, and ions. No consolidation or interpretive reports are produced from the acquired data, and this severely limits the usefulness of the data to environmental decision-making and to the public.

There are alternatives to the direct monitoring of the effects of land use practices on water quality. “Agri-environmental indicators” have been developed by the federal government and by Ontario to help determine how environmental conditions and trends within agriculture are changing over time, and what environmental risks exist within various areas. Decision-support tools for nutrient management planning on farms could be developed by Ministry of Agriculture and Food staff to ensure proper nutrient application rates under various soil, terrain and cropping system applications. Such tools can reduce the risk of contamination of surface and ground water by nitrogen and phosphorus from agricultural land. They are a step in the direction of sustainable agricultural practices and their use should lead to improving water quality over time. However, indicators and models are no replacement for long-term water quality data from a well-designed monitoring network that would represent the “bottom line,” indicating progress toward (or away from) our provincial water quality goals in the watersheds of rural Ontario.

More Effective Monitoring Needed for the Future

Aquatic ecosystems in Ontario are under tremendous stress from a variety of changes and environmental pressures. Reacting appropriately to these changes requires a commitment to monitoring programs that collect relevant data over the long term, that are technically state-of-the-art and that convey information to both experts and the public. Surface water quality is sensitive to season, time of day, temperature, flow-stage, spills, soil types, basin topography and many other factors. Stream and river monitoring networks have allowed only gross assessments of water quality and need upgrading to take better account of the dynamic effects of these processes in the monitored watersheds.

Most Ontario residents have little knowledge of the state of water quality in their local streams or lakes, or how the character of those water bodies might be changing as a result of climate change, changes in land use, population growth or other major forces. The monitoring programs Ontarians rely on to observe and report on surface water quality have become too fragmented and piecemeal to allow for accurate overviews. Now, more than ever, it is important for the province to take on the responsibility of determining the impacts on stream flows and water quality of such major influences. The province should have the ability to determine both present conditions and trends in water quality. Timely and pertinent information is important, as environmental managers cannot be put in the position of making decisions with outdated information.

In order for members of the public to be aware of the state of Ontario’s water resources, they must have ready access to relevant information. The ECO encourages MOEE to facilitate public access to data through innovative methods such as Web site downloads or on-line access to graphically presented data and trends. MOEE should consider possible interpretive approaches that display water quality data in comparison with Provincial Water Quality Objectives, Ontario Drinking Water Standards, or other relevant criteria.

In our 1999/2000 annual report, the ECO recommended that MOEE and MNR develop “current and comprehensive information that would allow for the development of scientifically defensible rationales for habitat protection activities and the identification of emerging ecosystem problems.” The need for adequate monitoring was also put forward in the report, Managing the Environment, prepared for MOEE in January 2001, which stated that comprehensive environmental information is the cornerstone of effective environmental management. MOEE has indicated in its 2001/2002 Business Plan that it is committed to implementing this principle of environmental management.

The ECO is pleased to note that the Ministries of Environment and Energy and Natural Resources are currently discussing plans for expanding hydrometric and water quality monitoring networks, in partnership with Conservation Ontario. These partnerships can have major cost efficiencies and can encourage local interest in and analysis of the database. The ECO encourages MOEE to continue to take the necessary steps to ensure that streams, lakes and rivers in Ontario are being monitored on a long-term basis and that the quality of our water resources is adequately assessed and reported.

Recommendation 5:

The ECO recommends that the Ministry of Environment and Energy institute an effective long-term provincial water quality monitoring program and make the resulting data readily available to the public.

This is an article from the 2001/02 Annual Report to the Legislature from the Environmental Commissioner of Ontario.

Citing This Article
Environmental Commissioner of Ontario. 2002. "Monitoring of Trends in Rural Water Quality in Southern Ontario." Developing Sustainability, ECO Annual Report, 2001-02. Toronto, ON : Environmental Commissioner of Ontario. 42-49.