We've been doing work on algal blooms at the Experimental Lakes Area for over 50 years. It started back when it was a federal institution. That's why the Experimental Lakes Area was actually started: to deal with the algal bloom issues in the Laurentian Great Lakes. They're very pervasive now. This is one of the biggest and the most ubiquitous issues around the world for fresh water.
Our position is that phosphorous is really the key element that we need to target. It comes from more than one source: point sources and non-point sources, and treated and untreated. It depends on where you are, which is most important. When we encounter a problem—let's say it's Lake Winnipeg or elsewhere—we say, first, let's target and find out exactly where this phosphorous is coming from, so that we can efficiently and effectively deal with the problem.
In the Lake Winnipeg watershed, for example, only 6% to 9% of the phosphorous is coming from waste-water treatment plants in Winnipeg. The vast majority is coming from non-point sources. In those circumstances, we say, “Focus the effort here on non-point sources because we need to deal with that problem.” In other areas, it's raw sewage or treated sewage.