DURHAM -- If nature is the infrastructure of our communities, as Robert Kennedy Jr. said in a visit to Peterborough in May, then certainly in Durham the foundation is the Great Lakes.

Mr. Kennedy delivered the keynote address at a Great Lakes research conference hosted by Trent University.

“What we are fighting for is not just the fishes and the birds,” he said. “We protect nature not for nature’s sake but for our own sake because it’s the infrastructure of our communities.

“If we want to meet the obligations of our civilization and our culture which are to create communities for our children that provide them with the same opportunities for dignity and enrichment as the communities that our parents gave us, we’ve got to start by protecting that infrastructure; the air that we breathe, the water that we drink, the landscapes that enrich us.”

The Great Lakes Basin is home to one very large community, made up of 40 million people, including 30 per cent of Canadians and 10 per cent of Americans. A majority of them draw their drinking water from the lakes. In addition to that, five million people fish the lakes every year.

The five lakes — Superior, Huron, Michigan, Erie and Ontario — contain within them  80 per cent of North America’s and 20 per cent of the world’s fresh surface water.

The health of the Great Lakes is a responsibility shared by two countries, including Ontario in Canada and eight states in America. It is affected by a large number of factors including industrial emissions pumped into the water and into the airshed, storm water, sewage and other byproducts of ubranization, runoff from agricultural lands and invasive species from other parts of the globe establishing themselves in the lakes.

As to how the lakes are doing, it’s a mixed bag.

Contaminants that cause fish-eating advisories in the Great Lakes — including mercury, a heavy metal, toxic compounds such as PCBs and byproducts of industry such as dioxins — persist in the environment.

This includes chemicals which have been banned for decades.

For example, mirex, a toxic insecticide used to control fire ants in the United States, can still be found in Lake Ontario despite the fact the product was banned in 1978.

“That (chemical) is so persistent you still find high levels in Lake Ontario,” said Douglas Holdway, a specialist in environmental toxicology from the University of Ontario Institute of Technology.

Dr. Holdway said some industries, such as the paper pulp industry which used to be a significant source of dioxins and mercury, have a good history of cleaning up their processes after having a black eye for many years. However, the concentration of other contaminants in the lakes such as PBDEs, a compound used as a flame retardant, are increasing.   

Members of the public must rely on a guide to eating sport fish, such as the one issued by the Province of Ontario (http://www.ene.gov.on.ca/envision/guide), to ensure they’re not consuming fish with high levels of contamination.

“The bottom line is you still get varying levels of contamination of Great Lakes fish and it certainly varies from some species that are safe to eat and some you shouldn’t eat at all,” said John Cooper of the Lake Erie management unit for Ontario’s Ministry of Natural Resources.

It also varies by lake and the size of the fish. As fish grow larger, they accumulate more toxins. The fish at the top of the food chain, such as salmon and trout, are less likely to be safe to eat because toxins accumulate within them.

Compounds such as PCBs will eventually break down over time; levels in the lakes have been dropping since they were banned in the 1970s. That’s not the case for heavy metals such as mercury, which has remained unchanged or improved only slightly.

“In the grand scheme of things, the most dangerous ones are the metals because they don’t break down,” said Dr. Holdway. At best, they can become trapped in sediment and prevented from entering the food chain.

And although mercury levels in the water are well below drinking water guidelines, in harbours around major urban areas levels exceed water quality criteria for the protection of wildlife, including fish and birds.

Overall, the quality of drinking water in the five great lakes is listed as good in the 2007 bi-national status report on the lakes.

“The water supply in Lake Ontario is a very good water supply. In terms of our water quality data, it’s a very good source and we haven’t seen any huge changes in water quality,” said John Presta, director of environmental services for the Region of Durham.

Beach water quality, on the other hand, is deteriorating in some areas, as a result of increasing amounts of algae. The proliferation of algae has been linked to the introduction of zebra and quagga mussels, invasive species from eastern Europe.

In fact, invasive species are increasingly and irrevocably changing the lakes, collapsing the aquatic food web which is considered to be severely impaired in all the lakes save for Lake Superior.

The mussels are just one example.

“We’re averaging one new invasive species every eight months,” said Mr. Cooper.

For more on invasive species and their effect on the Great Lakes, check out part two of this series .