Adirondack Lakes
212 Adirondack lakes show clear water with little algae, but higher nitrogen levels in the west, some from air pollution.
The preliminary analysis suggests a new threat to the once pristine waterways of northern New York from nitrogen overwhelming the natural filters of the forests and wetlands, changing lake chemistry. High levels of acid and mercury in Adirondack lakes from smokestacks to the west have already been well documented.
The question is whether the lakes are approaching a tipping point with levels of nitrogen and other nutrients that could turn them murky, algae-filled and unhealthy for people.
However, it may also be that nitrogen from the air pollution is going straight into the water. They are continuing their analysis to factor out the nitrogen released into the lakes by natural processes. Meanwhile, a plan to return to the Adirondacks this summer to sample 212 more lakes, expand the database and get a clearer picture of what's happening is in the works.
Other studies, by the state Adirondack Lakes Survey Corp., track the acid that has killed aquatic animals in several lakes -- damage at least partly addressed in 1990 Clean Air Act limits on sulfur dioxide emissions -- and the mercury that makes many freshwater fish in New York risky food for humans.
The nitrogen comes from smokestacks and tailpipes as well as organic material that breaks down in the forest watershed, feeding microbes at the start of the food chain and plants. The scientists are also examining a level of phosphorous, which, like organic nitrogen, feeds algae, but comes from fertilizer or sewage.
With little agriculture in the region, the Adirondack phosphorous threat comes mainly from lakeshore development. Researchers already know from rainfall testing that there's more air pollution on the western side of the park. That's also where the new water sampling shows higher nitrogen levels.
In the northwestern Adirondacks, the lakes also had higher chlorophyll levels, which is a measure of algae. They believe that combination of higher nitrogen and chlorophyll may be occurring naturally because those watersheds have a lot of organic carbon flowing from their wetlands.
The researchers found hot spots in a couple of lakes in the High Peaks region. Lake nitrogen levels tend to spike in the spring, with rain and runoff flushing uplands. Water samples were taken in summer, when levels tend to be low.
January 12, 2007 6:40 AM | Category: Chemicals, Cleanup