What’s in the water in the White Mountains? The answer, at least in part, is what’s in the air.
AMC’s Research department recently wrapped up a three-year air-quality analysis of 10 sites in the White Mountain National Forest (WMNF). The research, performed with the WMNF, was part of the Wilderness Stewardship Challenge, a U.S. Forest Service initiative designed to improve monitoring of Wilderness resources.
For the study, AMC staff and interns collected and analyzed the pH levels of water samples from streams in designated Wilderness Areas within the WMNF. By studying what’s in the streams, researchers are able to determine the impacts of acidic precipitation—a byproduct of polluted air—on water quality.
Researchers also monitored water chemistry for elements including calcium, magnesium, and potassium, and compounds such as nitrates and sulfates to determine the acid-neutralizing capacity (ANC) of stream waters in the WMNF. Over time, increasing ANC levels can indicate recovery from acid precipitation that occurred decades earlier.
“By analyzing cations and anions, we can calculate the ANC, which is an indicator of stream and forest health,” says Georgia Murray, an AMC staff scientist and the lead researcher on the project. Researchers also determined that factors such as slope, vegetation, and bedrock can affect a stream’s ANC.
Through AMC’s research, “We are seeing declines in sulfates and nitrates in the streams, which is consistent with cleaner air,” Murray says. Such improvements signal that public policy on cleaner air is working. “The significant reduction in acid rain is a success story for the Clean Air Act,” she says, noting that AMC’s long-term research has shown similar improvements in cloud water at Lakes of the Clouds Hut, on Mount Washington.
“We would have expected ANC levels to be better, but that could be a function of local topography and geology,” Murray says. For example, some streams are naturally acidic, and some local ecosystems may not have had enough time to sufficiently recover from the long-term effects of acidic precipitation.
The U.S. Forest Service is expected to use AMC’s findings as baseline data to inform future monitoring of air and water quality in Wilderness Areas, according to Murray. A related air-quality goal of the Clean Air Act is to reduce haze and to restore natural visibility in designated Wilderness to preindustrial levels by 2064.
Under federal law, designated Wilderness is managed to support the natural environment and its characteristics where, as the Wilderness Act of 1964 holds, “the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.” Mechanical devices such as vehicles and chain saws are prohibited in Wilderness Areas, where they are seen as intrusions on the Wilderness experience. Similarly, human-induced air pollution affects a visitor’s experience by diminishing scenic views and posing negative impacts on human and forest health.
If air quality improves, of course, we can expect cleaner air beyond the official Wilderness boundaries. “Smokestacks and tailpipes are the sources of this dirty air, and as we work to restore clean air to Wilderness Areas, the whole region will benefit,” Murray says.
As for reducing haze and enhancing visibility in Wilderness Areas, Murray says further advancements in clean-air policy will be needed to achieve the Clean Air Act’s 2064 goals. Meanwhile, she says, AMC will continue to engage in air-quality research, as it has for decades.