In August I interviewed University of Regina researcher Peter Leavitt (pictured) about a federal study that showed that lakes downstream of Wascana Creek were heavily polluted with nitrogen. With new federal guidelines set to come into effect, Regina is looking at spending $850 million* to build a new sewage treatment plant to reduce the amout of nitrogen and other pollutants we release in our waste water.

On Friday, an article co-authored by Leavitt and other researchers from the University of Alberta and University of Washington was published in Science magazine (here’s a link to a free abstract of the article).

It’s got a fair bit of technical jargon, but from information gleaned from a three-page press release that the University of Regina released yesterday, it seems that researchers tested deposits at the bottom of 36 lakes in the northern hemisphere. What they found was a significant increase in nitrogen levels. This wasn’t confined to lakes near sites of human habitation, either. Rather, it included remote bodies of water in the far north.

This is another example of what scientists describe as our entry into the “Anthropocene” era where the size and scale of human activites have reached a point where we are materially impacting on global biochemical cycles. Two of the biggest contributors to the increase in nitrogen, the report says, are the burning of fossil fuels and the use of agricultural fertilizers. Once released into the atmosphere (or discharged into a lake or river) the nitrogen is transported by air currents (or water flows) and ends up spreading over a wide area.

The scientists date the changes they observed to the late 19th century, and the widespread industrialization that occured then. As well, as Earth’s population has soared in the last century, fertilizer use has intensified to wring more food production out of our dwindling supply of arable land. With the world’s population expected to increase by three billion people in the next 40 years, Leavitt observes in the press release, the amount of nitrogen released into the environment through agricultural production and fossil fuel consumption will continue to grow, putting more stress on already endangered fresh water lakes.

*Ed Note: the waste water treatment plant is actually budgeted to cost $150 million, but city administration has identified another $850 million in expenditures that will be needed in the next 20 years to repair and replace aging pipes, pumps and reservoirs within Regina’s overall water delivery and treatment system. It’s also true that a lot of the nitrogen that’s entering the environment now, especially through agricultural run-off, doesn’t go through any treatment process. It simply moves from the land to whatever water source serves as a drainage point.