Nitrogen Control Fails to Clean Up Polluted Lakes

by Tanya Thomas on Jul 24 2008 11:50 AM

Researchers have realized that the process of nitrogen control may not be the answer to controlling the problem of cultural eutrophication, which is the addition of nutrients to a body of water due to human activity that often causes huge algal blooms, fish kills and other problems in lakes throughout the world.

The researchers were from the University of Alberta, University of Minnesota and the Freshwater Institute. 

The dramatic rise in cultural eutrophication has resulted from increased deposits of nutrients to lakes, largely from human sewage and agricultural wastes.

For 37 years, researchers looked at Lake 227, a small lake in the Canadian Shield at the Experimental Lakes Area (ELA) in Ontario, Canada, and examined the best ways to control the cultural eutrophication process of lakes by varying the levels of phosphorous and nitrogen added to the lake. 

“What we found goes against the practices of the European Union and many scientists around the world,” said David Schindler, professor of ecology at the University of Alberta and one of the leading water researchers in the world. 

“Controlling nitrogen does not correct the polluted lakes, and in fact, may actually aggravate the problem and make it worse,” he added. 

A previous study, entitled, “A Survey of the State of the World’s Lakes”, found that the cultural eutrophication of lakes has had a global effect. 

“The damage to these lakes is a major concern for virtually every continent,” said Schindler. 

According to Schindler, the impact on human society is immense, as cultural eutrophication severely reduces water quality, which not only kills and contaminates fish, shellfish and other animals, but also can become a health-related problem in humans once it begins to interfere with drinking water treatment.