Part 3
A Pyramid of Environmental Issues

 

"Sadly, the Great Lakes have long shown unmistakable signals of ecosystem stress and the imprint of our steadily deepening human footprint. In the early 1970s, eutrophication in Lake Erie reached a crisis point. Later that decade, deformities and rising contaminant levels in fishes and fish-eating birds became prominent concerns. In the 1980s attention focused on contaminated sediments and local hot spots, termed ‘Areas of Concern’. The latest binational report on the State of the Great Lakes highlights a now-familiar litany of environmental problems: ongoing damage by invasive aquatic species; deteriorated shoreline habitats; a worrying return of algal fouling of nearshore areas; and worsening trends in beach closures along the shores of Lake Erie and Lake Ontario.”

“Fixing the worst trouble spots has long been the focus of Great Lakes policy in Canada. Site specific remediation can be an effective tool for tackling the high variability within Great Lakes ecosystems and the need to tailor responses to local realities. But the COA’s [Canada-Ontario Agreement] focus on isolated trouble spots seems to have left little creative energy available for watershed-based thinking or proactive, preventive approaches.”

Engaging Solutions 2010/2011. Annual Report of the Environmental Commissioner of Ontario. 2011.

Chapter 10
Eutrophication Over-enrichment by nutrients caused algal blooms, water treatment problems, reduced deep-water oxygen. The Canada-US Great Lakes Water Quality Agreement required phosphorus reductions in detergents and municipal wastewater effluents. Targets were met in Lakes Erie and Ontario.

Chapter 11
Toxic Environment Many new synthetic chemical have appeared and so have abnormalities in fish and wildlife. Many degrade slowly and concentrate at the top of food-chains. A zero-discharge principle was adopted in the Water Quality Agreement.

Chapter 12
Alien Invaders total about 200 non-native species. Many were introduced in ballast water from seagoing ships. Zebra mussels increased nutrient flow to attached algae, clogged water-supply pipes and blanketed spawning areas.

Chapter 13
Acid Precipitation Is derived from airborne sulphates and nitrates from many sources. Reductions of emissions under the Canada-Us Air Quality Agreement have been promising, but more are needed.

Chapter 14
Climate Change Warmer temperatures occurred in the past three decades. Lower water levels and adverse changes in the lakes are possible. Canada and the US have increased greenhouse gas emissions and they have declined to support Kyoto protocols.