Consumers source of modern-day Lake Ontario contamination

By Dennis Hanagan –

A Lake Ontario core sample shows that consumers themselves are playing a role in chemicals winding up in lakes and rivers.

A Lake Ontario core sample shows that consumers themselves are playing a role in chemicals winding up in lakes and rivers.

Industry has greatly reduced the amount of pollution it puts into the Great Lakes, including Lake Ontario. But there are everyday things consumers can do to reduce water pollution even more.

“How consumers dispose of their products is very important,” says Paul Helm, who monitors the Great Lakes as a senior research scientist with Ontario’s environment ministry.

Helm, who hails from the city’s east end, was one of seven environmental speakers at an Oct. 27 seminar in Yorkville dealing with contaminants in the Great Lakes. It was sponsored by the Toronto and Region Conservation Authority, the Toronto and Region Remedial Action Plan, and Water Canada magazine.

Attendees heard that over a 30-year period ending in 1998, the amount of industrial contaminants such as PCBs, mercury and dioxins in the Great Lakes was reduced by 75%—“a dramatic reduction,” says Helm.

That’s the result—mostly—of Canadian and U.S. government remedial action programs that either restricted the use of chemicals or banned them outright. While some industries made efforts to get involved in the cleanup programs, others simply vacated the Great Lakes regions.

But these days, with population growth and people possessing new products in greater numbers, consumers themselves are playing a role in chemicals winding up in lakes and rivers.

In some cases there is not much consumers can do to prevent that. For instance, in some products, chemicals remain in dust particles as products wear and can become airborne and eventually settle in water bodies.

Flame retardants called polybrominated diphenylethers (PBDEs) found in furniture, textiles and building materials do just that.

But there are many products that consumers can dispose of under controlled circumstances. “We encourage everyone to follow the instructions on the product and avoid flushing or pouring any unused products down the drain, especially if they contain hazardous materials,” says Helm.

Even in landfill sites, products will disintegrate over time and their chemicals could leach into the water table. Instead of going into the trash bin, many products can be dropped off at municipal waste sites or returned to the point of sale where they will be safely disposed of. Electronics, paints, batteries, compact fluorescent light bulbs are examples. Unused medications can be returned to pharmacies.

Chemicals that go down toilets and household drains will end up in treatment plants. But while those plants remove nutrients and solids from the wastewater and add disinfectants to the effluent “they’re not designed for many of the chemicals we use,” says Helm.

For the most part, contaminants in Lake Ontario tend to concentrate on the American side because the lake is deepest there.

Concentrations in Toronto Harbour are not as high as elsewhere on the Great Lakes, says Helm, because there weren’t as many chemical manufacturers in the Toronto area. Also, because of the shape of the lake’s shoreline in the GTA, fine-grained sediments don’t accumulate to the same extent.

Researchers have a few methods to study contaminant levels in the lakes. Core sampling of sediments is one, but even mussels from Muskoka and herring gull eggs at Tommy Thompson Park are put to use.

Mussels accumulate contaminants in their tissue as they strain water for food. They’re placed in cages near potential pollution sites and their tissue is checked for contaminants.

Herring gull eggs are used the same way.  They’re checked at 15 sites around the Great Lakes, and those at Tommy Thompson Park are the eighth cleanest.