The Lake Huron Centre For Coastal Conservation
Advocating Wise Stewardship of Lake Huron's Coastal Ecosystems
Working Toward Clarity
Summary of the background report prepared by the Lake Huron Centre for Coastal Conservation on the state of Lake Huron's Water Quality
Prepared by Alison Sivers, Coastal Research Intern, Centre for Coastal Conservation
Water Quality is very much in the news these days and it is also a growing public concern. Water is one of the most important resources on the planet and affects nearly every aspect of life. The Great Lakes watershed contains a large percentage of the world's fresh surface water. The Lakes support the water needs, and jobs of millions of people and poor water quality is an increasing frustration.
The concept of water quality is most often used to describe the quality of water needed for human use. In reality, water quality is a combination of physical, chemical and biological properties of a water source that affect every living organism in contact with it.
There are many ways that water quality can become impaired. The majority of water quality concerns focus on the various pollutants that can be present in a water source including: chemicals and metals, nutrient enrichment, pathogens and bacteria, and calefaction (thermal pollution). A further concern in the Great Lakes is that of biological pollution. This refers to the introduction of alien species (ie. Zebra Mussels). Sources of pollutants are as diverse as the pollutants but can generally be classified into two sources - point source and non-point source.
Point sources include urban areas and sewage treatment plants as well as industries. Concerns in urban areas include runoff carrying chemicals, fertilizers, pesticides and suspended solids. As the amount of impermeable surfaces (pavement, houses, other structures) increases, there is a corresponding decrease in the amount of precipitation the ground is able to absorb. Instead, runoff is collected in storm sewers and dumped directly into a stream or the lake. Some towns along the Lake Huron coast had combined sewers at one point. During storm events, runoff would overload the capacity of the sewage treatment plant and dilute raw sewage was released directly into a stream or lake. Most of these systems have now been replaced or are in the process of being replaced, by separate sewer systems.
Bruce Nuclear Power Development (BNPD) The Bruce Nuclear Power Development (BNPD) is the largest industrial facility along Lake Huron. This industry impacts water quality in many different ways including the release of chemical pollutants, air pollution, landscape changes, and thermal pollution. The thermal plume located offshore from the BNPD has increased the abundance, size and overall quality of fish caught in the plume while at the same time having an negative impact on the reproductive abilities of fish that spawn in the area. The release of tritium, a radioactive isotope of hydrogen, appears to have little affect on fish in the area and studies have shown that level of tritium at water treatment plants in Kincardine, Port Elgin and Southampton do not exceed the annual average required by the Ontario Drinking Water Standards.
Non-point sources have a greater influence along this shore of the lake. These sources include: runoff (containing nutrients, pathogens and pesticides) from agricultural fields; leakage from improperly maintained rural septic systems; and air deposition. Manure is a major concern to water quality in the area. Manure is a source of nutrients and is useful as a fertilizer but if improperly applied few of these nutrients will be retained by crops. Instead they will end up being washed off the field by rain and end up in the lake or in streams. Manure is also a source of bacteria and pathogens that can have a negative affect on human health.
In the open water (the middle of the lake) the major concern is air deposition. Various types of chemicals can be carried huge distances in the atmosphere. The pesticide DDT is a good example. Although use of DDT has been banned in United States and Canada, DDT is still used in third world countries and is still showing up in the Great Lakes. Other atmospheric concerns include chemical and toxins that remain in the atmosphere for a much shorter period of time. Air pollution from industries within the Great Lakes Watershed takes less than a day to reach the Lakes. On top of that, the air quality of the Ontario Lake Huron Shoreline is among the worst in Southern Ontario. Ground level ozone levels have been measured at nearly twice those of Toronto. Other chemicals that can be deposited into Lake Huron via the atmosphere include pesticides, lead, mercury, PCBs, furans and dioxins.
Near shore' water quality refers specifically to the water quality of the lake within a reasonable distance from shore. This would be where most human contact occurs. The most prominent concerns affecting this area are nutrient enrichment and the presence of pathogens. Pathogens are small microorganims, including E. coli. The major source of these pathogens is fecal material from septic systems, livestock, pets and wildlife. Health risks associated with swimming in water with high levels of coliforms (E. coli and other fecal bacteria) are usually limited to minor skin, ear, eye, nose and throat infections or irritations and stomach disorders. However, the risks increase for those with under-developed or surpressed immune systems (ie. small children and the elderly).
The source of excess nutrients often comes from the same sources as pathogens - agriculture and septic systems especially. Excess nutrients result in accelerated algal growth, which can have significant negative aesthetic qualities, unlike E. coli, other pathogens and chemical, which cannot be seen with the naked eye. Accelerated algal growth, or algae blooms, can result in fish kills from anoxia (no oxygen), and can cause taste and odour problems.
An estuary is the region where a river feeds into a lake where the chemical and physical properties of the water are influenced by both the stream and the lake. Two of the major concerns in these areas of the lake include sediment loading and sediment contamination. Sediment loading refers to high levels of suspended solids being washed into creeks and rivers and carried down into the lake. This is a natural process to a certain point but loadings can increase as a result of human activity. Increased sediment loadings can be caused by deforestation, dredging, roadway and pipeline construction among other causes. Increased loadings can affect the ecosystems where they are deposited, including decreasing primary productivity (reduction of light penetration), and decreases in food sources for fish, crustaceans and other organisms.
A further concern of unnatural loading is that of sediment contamination. As time passes, suspended solids in the lake will eventually settle to the bottom. Some of these particles can become contaminated with toxic substances. When the particles settle to the bottom, these chemicals and toxins will be removed from the water column and be concentrated in the sediments. If the sediments are stirred up the particles can be resuspended and can re-enter the food chain. Another way that the toxins can re-enter the food chain is through bioaccumuation and biomagnification. Small invertebrates in the sediments will consume the toxin and they will be accumulated in body tissue. These inverterbrates are then consumed by larger organisms. The ratio of toxins to body tissue at each level of the food chain will increase eventually amounting to a level that can result in sickness or death.
There are many different groups concerned about the water quality of the Great Lakes. In 1972, Canada and the United States signed the Great Lakes Water Quality Agreement. This agreement committed both countries to cleaning up waste entering the lakes. The agreement concentrated on the cleanest (Superior) and worst off lakes (Erie and Ontario). For awhile it seemed that Lake Huron had been forgotten. In 1997 an informal, bi-national effort call the Lake Huron Initiative was formed and an Action Plan was developed. At the provincial level, the Ministry of the Environment has worked with thousands of public and private sector organizations to improve the environmental quality in the Great Lakes.
Along the coast of the lake, from Sarnia to Tobermory, there are more than 40 local agencies and organizations, including the Lake Huron Centre for Coastal Conservation, who are interested in water quality. There are 13 municipalities, 5 conservation authorities, 3 County Health Units, as well as many more localized community associations. These groups have the potential to make significant contributions to water quality through action and education, but a major concern is the lack of communication and organization between groups.
The water in the Great Lakes basin supports millions of people and as a result, water quality is a growing concern.
 |
The Lake Huron Centre for Coastal Conservation P.O. Box 178, Blyth, Ontario, Canada N0M 1H0 Phone: (519) 523-4478 Email: coastalcentre@lakehuron.on.ca |
|
