Lake Erie And Phosphorus Part 2: The Problem With Controlling Phosphorus

My last blog post focused on the story of degradation and recovery of Lake Erie from the 1960's-70's, and primarily on the effect that phosphorus had on the lake.  Although controlling the amount of phosphorus entering the lake was a more prevalent issue for Lake Erie in the past, it is still an issue today.

The Great Lakes Water Quality Agreement did, and still does, much to reduce the amount of phosphorus entering Lake Erie, and in turn helped return the lake to some of its former health. But the problem is that the agreement only helps to manage point sources of phosphorus, nitrogen, and other pollutants entering the lake, whereas much of the phosphorus entering Lake Erie does so through non-point sources.  To be clear, point source pollution refers to a source of pollution that enters the environment through a specific entry point, i.e: an industrial plant discharging polluted water into a river.  Non-point source pollution refers to the opposite, a source of pollution that enters the environment through a non-specific entry point, i.e: pollutants dispersed by rain.

And so, while the agreement can regulate with relative ease the amount of phosphorus based fertilizers being used in agriculture, and can even place a ban on all phosphorus based detergents, it cannot regulate the amount of phosphorus (or other pollutants) entering the lake through the atmosphere, which today consists of one of the primary sources of non-point source phosphorus pollution in the lake.  Other sources of non-point source phosphorus include run-off from roads, phosphorus fertilizers which dissolve in water, and then collectively make their way through the soil to the lake, etc.  Because of our lack of ability to directly manage non-point sources of phosphorus entering the lake, a lot of emphasis is placed on controlling point-sources of phosphorus in order to make up in part for the ample amount of phosphorus entering the lake through other means.

However, even though non-point sources of phosphorus pollution cannot be directly managed, these non-point sources are formed by a variety of single sources, which then in combination form the aforementioned non-point sources of phosphorus.  Many of these individual sources derive from homes and communities, and thus can be controlled by those responsible for them.  In consequence, if each individual source is better controlled by the respective individual(s) responsible for it, then so too will be the accumulative amount of phosphorus entering the lake.  Such individual sources include, but are not limited to excess lawn fertilizer run-off, lawn clippings, roof run-off, etc.

Although a single actio

The image above demonstrates basic ways in which phosphorus can enter a large body of water, such as lake Erie.

Sources:
1. http://www.epa.gov/glnpo/atlas/glat-ch4.html
2. http://ohioseagrant.osu.edu/_documents/publications/FS/FS-046%20Lake%20Erie%20water%20quality%20past%20present%20future.pdf
3. http://www.lakeaccess.org/lakedata/lawnfertilizer/p-diagram.htm
Images:
http://www.lakeaccess.org/lakedata/lawnfertilizer/p-diagram.htm


Video links :

- CBC news report (1979)

http://www.cbc.ca/archives/categories/environment/pollution/troubled-waters-pollution-in-the-great-lakes/lake-erie-lives-again.html