(Host) A new study concludes that increased nitrogen from water and air pollution is causing a wide range of environmental problems in the Northeast. The study was conducted by the Hubbard Brook Research Foundation in Hanover. Researchers say it’s the first comprehensive look at the effects of increased nitrogen on the forests and waters of the region.
Scott Ollinger is an Assistant Professor at the University of New Hampshire and a co-author of the study. Ollinger says nitrogen from a variety of sources is affecting the environment in complex ways. He says in recent years, emissions controls on power plants have cut down on sulfur pollution, but the amount of nitrates in acid rain remains high. That has a detrimental effect on forest health. Ollinger makes a comparison between a diet high in salt and a soil high in nitrogen.
(Ollinger) “When we think about forest ecosystems, these are ecosystems that have evolved over thousands or millions of years in very low nitrogen conditions. And we’re suddenly loading them with nitrogen. So one way to think about this is we’re concerned about that forests, in effect are suffering from high blood pressure if you will.”
(Host) Ollinger says there’s evidence increased nitrogen in the soil is harmful to conifers and to sugar maples. High levels of nitrates also cause ground level ozone, or smog – an increasing problem in New England. The study found that smog is stunting tree growth in the Northeast. In the Bennington area, for example, the growth rates have declined ten percent.
The study also documents the impact of increased nitrogen levels on water quality in the Northeast. Surprisingly, Ollinger says the biggest source of nitrogen pollution isn’t acid rain or fertilizer runoff from farms.
(Ollinger) “And then the third, which we often don’t think about, but which tends to be the largest source overall, is nitrogen that gets imported into the region that’s contained in food. And when we talk about nitrogen that’s emitted from waste water treatment plants, initially that nitrogen was derived from food.”
(Host) That’s why the study recommends improving wastewater treatment. It also calls for a reduction in emissions from vehicles and electric power plants.