Great Lakes Article:

Billions of litres of untreated urban sewage and toxic effluents that flow into the Great Lakes each year are threatening a critical ecosystem that supplies drinking water to millions of people, a landmark study to be released Wednesday concludes.

Even though municipalities in the Great Lakes region have spent vast sums of money in recent decades upgrading their waste-water plants, the situation remains appalling, says the report by the Sierra Legal Defence Fund.

"The problem of inadequate sewage treatment is particularly disturbing because sewage is not simply what gets flushed down our sinks and toilets," the report states.

"In fact, typical municipal sewage is a foul cocktail of human waste, micro-organisms, disease-causing pathogens and hundreds of highly toxic chemicals."

Sierra Legal bills the study of 20 Canadian and American cities as the "first-ever ecosystem-based survey and analysis" of municipal sewage treatment and discharges into the Great Lakes basin.

The survey graded municipalities in areas such as collection, treatment and disposal of sewage based on information provided by the local governments.

The main problem, the study concludes, is that in many cases, antiquated sewage systems are incapable of dealing effectively with the vast amounts of effluent that flow through them.

The situation is especially bad when heavy rains overwhelm treatment systems in cities where storm run-off is collected in the same pipes as sewage.

Some 90 billion litres of untreated effluent enter the Great Lakes every year through combined sewage overflows, the study found.

That's the equivalent of more than 100 Olympic-sized swimming pools full of raw sewage every day, Elaine MacDonald, the scientist who did the study, said in an interview.

At the same time, it takes about a century for the Great Lakes to completely recharge.

"When you think of 100 years to flush out the Great Lakes and 100 years of sewage being dumped in at this rate, that has quite an impact on quality of the water," MacDonald said.

Canada's worst offender was Windsor, Ont., which — along with U.S. cities Detroit and Cleveland — performed "abysmally." Cities such as Toronto and Hamilton also earned below-average grades.

At the top end, Peel Region just west of Toronto, Green Bay, Wisc., and Duluth, Minn., were the best performers, thanks largely to their ability to keep rain water and sewage separate.

The report makes several recommendations, including improving water conservation in order to reduce the flow to sewage plants, and keeping rain water out of sewers by disconnecting downspouts and separating storm drains and sewer systems.

It's critical to keep toxins out of drains, the report notes, given that many sewage-treatment plants are incapable of dealing with them and hazardous substances end up in the lakes, or in sludge that is used for agricultural purposes or dumped in landfills.

"We need to change our ways and stop treating the Great Lakes like a toilet," the report concludes.

The report also calls on national, provincial and state governments, along with scores of municipalities, to work together to beef up infrastructure, harmonize legislation and ensure enforcement.