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Professor Lewis Molot on why Canadian phosphorus ban will help our lakes

Professor Lewis Molot on why Canadian phosphorus ban will help our lakes

Excessive phosphorus dumps have become a major problem for Canada’s waterways, says Professor Lewis Molot, an environmental scientist in York University’s Faculty of Environmental Studies, wrote the National Post Jan. 6 in a story about a little-known move by the federal government banning the substance:

The federal government brought in new regulations last July effectively banning phosphorus in most household cleaning products, such as dishwashing and laundry detergents. The new rules prohibit the manufacture and import of these products containing phosphorus beyond 0.5% by weight. Similar regulations in the United States banned the chemical in 17 states.

Phosphorus in certain detergents and cleaning products softens water, reduces spotting and rusting , holds dirt, and increases performance. But it is also a plant fertilizer, Prof. Molot says, meaning when it enters a lake, it causes massive amounts of algae to grow.

"When the algae die, they sink to the bottom of the lake and are consumed by bacteria. In the process, these bacteria consume all the oxygen, leading to the asphyxiation of fish," Prof. Molot said.

The chemical also causes algal blooms -- massive green blob-like growths -- which can raise pH levels in water to toxic levels and block water intake pipes. Prof. Molot says dirty dishes are a small price to pay for preventing the spread of phosphorus.

"Either the public pays huge amounts of money to remove the phosphorus at the end of the pipe, or it can choose the cheaper alternative to reduce the amount of phosphorus going into our sewers in the first place," he said. "If I have to pay a little more for a greener detergent, even if it means it doesn't clean the way it used to, I'll put up with it."

Molot has published on phosphorus' effect on northern Ontario's s freshwater lakes, most recently in February 2010. His research is funded by the Natural Sciences & Engineering Research Council of Canada (NSERC).

Posted by Elizabeth Monier-Williams, research communications officer, with files courtesy of YFile– York University’s daily e-bulletin