Manitoba's Liberal leader plans to introduce a private member's bill that would ban phosphates in dishwasher soap, saying that they're polluting Lake Winnipeg.

Jon Gerrard said Tuesday that such a ban, which would affect most major brands, would be similar to a nationwide regulation introduced in the early 1970s that dramatically reduced the percentage of phosphates in laundry detergents.

That regulation, spurred by concern for the Great Lakes, limited the phosphate content of laundry detergents to five per cent from as much as 45 per cent. However, it didn't restrict other cleaners.

Many popular dishwasher detergents, whether they're in powder, liquid or tablet form, contain phosphates that, when they go down Manitobans' drains, eventually end up in Lake Winnipeg. Phosphorus acts as a fertilizer, promoting algae and aquatic weed growth.

"Lake Winnipeg, as everybody knows, is in dire straits at the moment. Huge algal blooms, far too much phosphorus," Gerrard said.

"This is one of those things that all of us can do, and that is to use phosphate-free detergents instead of using detergents containing phosphates and increasing the load of phosphorus on Lake Winnipeg."

This summer, cottagers along Lake Winnipeg have complained of an increase in algae blooms on the lake's surface.

Greg McCullough, a University of Manitoba researcher who studies the algal blooms, estimated the average household dishwasher uses 500 grams of detergent in a year, and such detergent typically contains two- to eight-per-cent phosphates.

McCullough said Tuesday he agrees that phasing out dishwasher detergents containing phosphates is one of the simpler things people can do to cut down on phosphorus pollution in the lake.

Gerrard said there are effective phosphate-free dishwashing soaps on the market, usually at specialty shops that sell organic soap. He admitted they do tend to cost more, but his proposed ban could change that.
 
"One of the things that made a big difference to Lake Erie back in the 1970s was banning phosphates in laundry detergents," he said.

"It was done then, it can be done now for these products. We need to ban it so it's uniform. What will happen is the price will come down once everybody has to use the same product."

Gerrard said the tablet varieties of dish detergent are the worst offenders in terms of phosphate content, followed by powders, with gels being the best choice.