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REVIVING THE WATERS: |
In 1969, a floating oil slick on the Cuyahoga River burns for hours in Cleveland, Ohio, where the waterway empties into Lake Erie -- one of the five American Great Lakes that make up the world's largest system of inland lakes. Newspapers declare "Lake Erie is Dead."
In 1970, mercury pollution in Lake Erie and other waterways in the Great Lakes system bordering Canada and the United States leads to a ban on fishing in parts of the region. A chemical plant in Canada is thought to be the source of potentially dangerous discharges.
In 1970, the state of Michigan issues a warning to the public about consumption of fish from Lake Michigan. High levels of residues from toxic PCB (polychlorinated biphenol) are found in lake trout and salmon.
In 1972, the U.S. Congress passes the Clean Water Act.
These events through the 1960s and 1970s were critical in developing a national awareness about the damage done by unregulated industrial and wastewater discharges into the Great Lakes. The pollution of this magnificent natural resource became a celebrated cause for environmental activists, just beginning to build public support at that time. Today, substantial progress in the clean up of this unique water system is one of the nation's great environmental success stories.
The following excerpts from a report tracking the restoration of the Great Lakes was originally published in January 1998 by the Office of the Great Lakes, Michigan Department of Environmental Quality. The report is available in full at http://www.deq.state.mi.us/ogl
GREAT LAKES TRENDS: A DYNAMIC ECOSYSTEM
In 1972, the United States and Canada signed the Great Lakes Water Quality Agreement. The agreement was amended in 1978 and 1987. The purpose of the agreement is "to restore and maintain the chemical, physical, and biological integrity of the waters of the Great Lakes basin ecosystem." Both parties, the United States and Canada, agreed to "make a maximum effort to develop programs, practices, and technology necessary for a better understanding of the Great Lakes basin ecosystem, and to eliminate or reduce to the maximum extent practicable the discharge of pollutants into the Great Lakes ecosystem." In the agreement, the Great Lakes ecosystem is defined as "the interacting components of air, land, water, and living organisms, including humans, within the drainage basin of the St. Lawrence River at or upstream from the point at which this river becomes the international boundary between Canada and the United States." The agreement represents a broad commitment to Great Lakes basin health.
The World's Twelve Largest Lakes
The five Great Lakes hold more than 6,000 trillion gallons of water, about one-fifth of the world's fresh surface water supply. This ranks them among the 15 largest lakes in the world by surface area and volume. These lakes provide drinking water to 23.5 million people. Residents in both the United States and Canada rely heavily on the lakes for not only drinking water but also for recreation, food, and transportation.
The open waters of the upper Great Lakes, being Superior, Michigan, and Huron, have excellent water quality overall. The only exceptions are a few degraded locations restricted to nearshore zones and mainly in urban areas. Lake Huron's water quality has improved even more in the past few years resulting from improved quality in the Saginaw Bay. Moreover, Lake Erie water has drastically improved over the last two decades.
In 1980, the focus of the activity on the Great Lakes was toxic chemicals, nutrient loading, and their effects on wildlife. The sustainability of the Great Lakes fisheries, including the impact of exotic species introduction, then became a paramount issue. Below is a summary of the most apparent trends through the early 1990s:
The Great Lakes watershed continues to have problems with persistent bioaccumulative toxics such as PCBs, chlordane, mercury, and dioxin. Based on the amount of PCB uptake by fish, water quality standards are not being met for PCBs in Michigan waters of the Great Lakes. Since the 1970s, when many persistent bioaccumulative toxics such as PCB and DDT were banned, levels of these toxics in Great Lake fish tissues have declined. However, the rate of this decrease in measured toxics appears to have slowed in the last few years. Currently, contamination from these persistent bioaccumulative toxics is believed to come primarily from in-place pollutants resulting from historical discharges and atmospheric deposition.
Also, the loss of coastal wetlands and shorelines has accelerated. The wetlands and shorelines that existed in the Great Lakes basin are only a fraction of the system that occurred two centuries ago. For example, an 80 percent loss on Lake St. Clair, a 70 percent loss on Lake Erie, and a 50 percent loss of coastal wetlands in Saginaw Bay have been reported.
Wetland loss changes the biological and chemical make-up of the waters that pass through them to the open waters of the Great Lakes. The adverse effects to wetlands from dredging, draining, diking, pollution (particularly sedimentation), and water level management have contributed to degradation of Great Lakes water quality and the decline of fish and wildlife populations dependent on the coastal and river mouth areas of the Great Lakes.
Very little is known about recent changes in the abundance of coastal wetlands based on surrounding conditions. Regulatory programs at both the state and federal levels have essentially achieved a "no net loss" goal for coastal wetlands, at least in terms of direct losses from land use changes. High water levels, wave erosion, and other natural processes are more likely to be responsible for any significant changes in coastal wetlands.
The National Oceanic and Atmospheric Administration, in cooperation with the U.S. Geologic Survey, is updating obsolete shoreline maps of the Great Lakes. They discovered that offshore sand of southwest Lake Michigan shore, which provides protection for the underlying glacial till and for the bluffs along the margins of the lake, was thin to non-existent in many areas, due to geologic processes during the past 50 years. They intended to study the processes affecting sand movement in order to better determine the most effective long-term shoreline and property protection measures. The study, initiated in 1991, took place from St. Joseph, Michigan, south to Michigan City, Indiana.
Great Lakes policy has expanded from one that was focused on chemical pollution toward a broader view that also encompasses physical and biological threats, including habitat destruction and exotic species introduction. In the 1992 National Water Quality Inventory Report to Congress, the U.S. Environmental Protection Agency reported that 95 to 100 percent of the rivers and inland lakes assessed in Michigan received a "good" rating. However, there are still problems that remain. The major problems associated with Michigan rivers are fish consumption advisories, siltation, and contamination by metals and bacteria. The reports identified significant concern in the assessed areas primarily demonstrated by the existence of public health fish consumption advisories.
All Michigan waters of the Great Lakes fully support secondary contact recreation (non-swimming), agriculture, industrial, and navigation uses. Less than two kilometers of Great Lakes shoreline is not meeting swimming use requirements due to beach closings related to bacterial infestation of Lake St. Clair. However, local health departments routinely issue total body contact advisories in areas downstream of combined sewer discharges to the connecting channels (e.g. St. Marys River). Some water at the intake in Saginaw Bay also is not meeting drinking water standards. Aquatic life use, as inferred from fish collected in 1994 and 1995, is not fully supported due to fish consumption advisories for the Great Lakes. However, some fish consumption advisories have been revised, removed or relaxed.
SUMMARY
The general long term trends of the Great Lakes are:
Toxic: General decrease of concentrations in water over the last 20 years. However, the rate of decrease has slowed. Open water sediment concentrations have decreased. Localized area problems and some chemical specific issues still exist.
Conventional Pollutants: Nutrient levels have decreased. Dissolved oxygen levels have improved. Chloride and nitrogen levels appear to be increasing.
Land Use: Continued loss of coastal wetlands occur in some areas; residential and commercial areas are expanding; agricultural lands are declining. Land use decisions in the Great Lakes basin impact the quality of the Great Lakes.
Water Levels: Projected water levels are high and show no immediate return to the long-term mean.
Fish: Some improvements in Great Lakes fisheries have been realized. Contaminant levels in fish have decreased, but the rate of decrease has slowed. Habitat destruction and introduction of exotic species are a serious concern.
Birds: Great Lakes fish-eating birds have shown population increases, the important limiting factor being physical habitat.
Exotic Species: Nonindigenous aquatic species such as the zebra mussel, ruffe, round goby, spiny water flea, sea lamprey, and others have the potential to cause significant ecological harm.
Human: Human use of the Great Lakes has increased, while potential impacts of Great Lakes-induced health effects are still a potential concern due to bioaccumulating persistent chemicals.
The trends identified in this report represent both positive effects of historical efforts to control environmental stressors in the Great Lakes and reason for concern due to the fact that the downward trends for many chemicals may be leveling off and the impact of changing land uses on Great Lakes water quality. This information should be celebrated for the progress it documents while encouraging continued effort to improve our valued Great Lakes ecosystem.
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