CHARLOTTESVILLE, Va. (AP) — A long-term study conducted by University of Virginia scientists shows that Virginia's trout streams are rebounding from acidification, though not as fast or as thoroughly as waters in some other parts of the country.
The results were derived from a series of extensive surveys of water quality, conducted in 1987, 2000 and 2010. More than a hundred volunteers many from Trout Unlimited, which is cooperating with UVa on the study fanned out across the state's mountains to collect this year's samples.
Most trout streams are in forested mountain watersheds, where the cool, oxygen-rich water that trout love is most common. Volunteers hit streams from Shenandoah County in the north to Scott County in the south. Locally, water was drawn from sites in the western parts of Madison, Greene, Albemarle and Nelson counties.
"I think brook trout sort of represent what's best of what remains of the natural world,'' said Rick Webb, a UVa scientist and the project's coordinator.
Brook are the native trout of the East Coast, revered by anglers as symbols of pristine nature more than for size or fight. Top predators in their environment, the trout range from deep green along their backs to yellow-pale bellies, their sides speckled with reds and blues.
They aren't particularly sensitive creatures in the streams, unlike other creatures such as mayflies.
"The aquatic community is degraded long before the trout disappear,'' Webb said.
Brook trout are sensitive to a variety of other factors related to water quality, he said, and other species of trout, some of which reproduce in the wild in Virginia, can be more sensitive to acid than are native brook trout.
The study's results showed a marked improvement in water quality for brook trout since 2000, in contrast with the infinitesimal uptick in water quality scientists found between 1987 and 2000.
Scientists measured sulphate levels in the streams, as well as acid neutralizing capacity. When sulphate from the atmosphere reaches water, it turns to sulphuric acid. It's best known as acid rain, though rain isn't the only way it can end up acidifying waterways.
Median sulphate levels dropped by about 6 percent from 1987 to 2000. From 2000 to 2010 they dropped roughly 13 percent.
Median acid neutralizing capacity increased about 16 percent between the first and second surveys and 55 percent between the second and third surveys.
The results are still preliminary, and researchers are still working to calculate what effect differences between water levels from year to year have on the data, but indications are that their findings won't change significantly, Webb said.
While Virginia has seen notable improvement, it's not as pronounced as the improvement seen in states in the Northeast. Webb attributed the variation mostly to differences in soil types.
"Things have not fully recovered by any means,'' Webb said.
The ground in some parts of Virginia will have a delaying effect on improvements, while other areas are permanently degraded, Webb said.
"Many of the streams that have been most impacted are likely not ever to recover, at least in a human timeframe,'' Webb said.
Webb attributed much of the improvement that has occurred to the most recent amendments to the Clean Air Act. The amendments were passed in 1990, but phased in since.
According to the Environmental Protection Agency, the Acid Rain Program, which was part of the 1990 amendments, has helped to reduce sulphur dioxide emissions to 33 percent of 1980 levels.
"Nationwide, it's a success story,'' said Frank Rambo, a senior attorney with the Charlottesville-based Southern Environmental Law Center.
The program created a cap-and-trade system for sulphur dioxide emissions from power generation, a phenomenon most commonly associated with coal-powered electricity generation. Sulphur dioxide is a precursor to acid rain.
At the time, there was heated opposition to the move, Rambo said.
A cap-and-trade program sets limits on how much pollution a given plant can produce. If companies beat the target, they get a credit that they can sell to companies that don't hit their targets. The program was implemented gradually, expanding to cover more plants and ratcheting down the caps. The last phase took effect this year, according to the EPA.
Modern coal-fired power plants can capture between 95 percent and 99 percent of the sulphur dioxide they create, said Steve Gates, spokesman for Americans for Clean Coal Electricity, an industry lobbying group.
Rambo said other EPA regulations, not intended to combat acid rain, also have cut emissions chemicals that contribute to the problem.
Webb cautioned that, while there's been improvement, there are still chemicals damaging the environment.
"Even though sulphate deposition has been reduced, it certainly hasn't been reduced to background level,'' Webb said.
Gates said that acid deposition is not at the forefront of Washington debate these days.
"What you hear is how much (sulphur dioxide) can be reduced,'' he said.
