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A Guide to the GLWQA >
Successes and Challenges for the Great Lakes Water Quality Agreement
Both countries have made considerable progress in reversing the impacts of chemical, physical, and biological damage to the Great Lakes and St. Lawrence River ecosystem. Tremendous efforts have been made to clean up the lakes and protect them from further pollution, and governments at all levels have put billions of dollars to the task. Industries have made significant strides in changing production processes, the products produced, and cleaning up contaminated areas. Municipalities, often supported by other levels of government, upgraded sewage and water treatment facilities across the basin, particularly in the early phases of work under the Agreement. Community and environmental groups have worked tirelessly to monitor progress and improve the environmental condition of the Great Lakes and St. Lawrence River system.
A lot has been done, but much more is needed to fulfill the Agreement's mission to fully restore and maintain Great Lakes water quality. Governments identified specific objectives and developed water quality criteria and regulations to achieve them, but important developments in computer modeling and advances in biological and environmental science have shown that what once was thought to be "enough" is not sufficient to protect vulnerable populations of humans, fish and wildlife. Two good examples of this dilemma are reductions in phosphorous loading and the input of persistent toxic substances such as PCBs and DDT.
Phosphorus
Persistent Toxic Substances
Remedial Action Plans for Areas of Concern
The Cost of Restoring Great Lakes Areas of Concern
Phosphorus
In the 1960s, excessive algal growth in the Great Lakes adversely impacted water quality. Canada and the United State s responded with aggressive programs to reduce phosphorus inputs through the use of phosphorus-free detergents, improvements to municipal and industrial sources, as well as using best management practices to improve the quality of runoff from agricultural lands and stormwater from urban areas.
Recent open-lake total phosphorus concentrations for Lakes Michigan, Superior, Huron, and Ontario suggest that the Agreement's goals for phosphorus reductions have been met for these lakes. Concentrations in the three basins of Lake Erie fluctuate from year to year and frequently exceed target concentrations. In Lakes Ontario and Huron, some offshore and nearshore areas and embayments experience elevated levels that can promote nuisance algae growths.
Comprehensive monitoring programs for loadings of phosphorus from nonpoint sources have been curtailed, limiting our ability to track the sources of phosphorous: phosphorous loading to certain nearshore waters remains a persistent problem. Changing nutrient dynamics that result in phosphorous enrichment and subsequent seasonal low oxygen conditions because of aquatic invasive species (biological pollution) in Lake Erie are suspected but not yet verified. No clear solutions have been identified for these type of complex nutrient management challenges.
Persistent Toxic Substances
In this example, the governments established a policy to virtually eliminate the input of persistent toxic substances into the Great Lakes environment. Their Binational Toxics Strategy, adopted in 1997, has furthered this policy through a range of innovative partnerships within the health care, energy, manufacturing, governmental, non-governmental and other sectors. Through other national and Great Lakes-specific programs and initiatives, the two governments have made considerable progress toward achieving this goal. For example, the two countries have tracked total polychlorinated biphenyls (PCBs) and total DDT in lake trout tissue samples from Lakes Superior, Michigan, Huron, and Ontario and in walleye from Lake Erie over several years. Results from fish collected in 2000 show some impressive improvements. However, these lakes have and continue to receive inputs of persistent toxic substances from a variety of point and nonpoint sources, and all of the Great Lakes and their tributaries continue to have advisories to limit fish consumption.
See table.
Remedial Action Plans for Areas of Concern
Remedial activities in Areas of Concern (AOCs) are important steps to restoring and protecting water quality-related environmental conditions. Despite encouraging progress, 41 of 43 AOCs still require action and monitoring. The Commission completed a special report on AOCs in 2003 that examined the status of restoration activities in these locations. It identified wastewater infrastructure improvements and contaminated sediment remediation as the most significant remedial activities needed to restore the AOCs. The report details the dollars spent to date and the estimated costs of planned remediation actions, providing a measure of how far we have come and how far we still have to go.
Restoration efforts for the AOCs and the lakes as a whole are complicated by new chemical issues, such as inputs of polybrominated diphenyl ethers, and emerging biological challenges such as aquatic invasive species. These and other issues limit our collective ability to define timelines to completely restore AOCs and the lakes. Further reductions in levels of persistent toxic substances will be difficult to achieve due to their usage in other countries and subsequent global airborne transport and deposition within the Great Lakes basin. Residual quantities will remain in contaminated sediment, and continued domestic use and transport from upland sites will continue their discharge into the lakes. In some areas, it will be necessary to rely on natural recovery to eliminate contaminated sediment, and recovery times could range from 10 to 80 years or longer.
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