From the April 2008 Conservationist
Photo: Carl Heilman II
Acid Rain, Rain Go Away
Some Adirondack lakes are showing promising signs of recovery
By Shannon Brescher Shea
Writers and artists have long celebrated the vibrant beauty of the Adirondacks. Its majestic mountains, stately forests, and pristine waters have been the subject of countless books, poems and paintings.
In the recent past, however, acid precipitation has dimmed that radiance, leading to damaged forests and depleted lakes. Thankfully, this trend is shifting. Both the federal government and New York State's actions have resulted in a decrease in the pollutants that cause acid rain. Consequently, its drastic impact on the region is now diminishing, and the Adirondacks' ecosystems are showing promising signs of recovery.
While acid rain is familiar, acid precipitation and deposition comes in many forms, including rain, snow, sleet, hail, fog, and as deposits of particles and gases. A byproduct of our industrialized society, it is formed when sulfur dioxide (SO2), nitrogen oxides (NOx), and ammonia (NH3) combine with moisture in the atmosphere to produce sulfuric and nitric acid. Emissions from coal-fired power plants, vehicles and factories are the major sources of these pollutants. However, wind patterns often blow many of these pollutants far from their origins. For example, emissions from the Midwest's heavy industries, after combining with precipitation, eventually fall as acid rain in New York State.
Just as adding the wrong ingredient to a baking recipe can spoil a cake, adding acid to a natural environment can destroy its balanced chemistry. Changes in the acidity of water or soil interfere with resident species' natural processes. As many fish are sensitive to changes in acidity, lakes suffering from acidification exhibit declines in fish species and populations. Many native fish, such as brook trout, have experienced reduced natural reproduction, decreased abundance and even total elimination in certain waters. If your fishing catch in the Adirondacks seems meager compared to the legendary catches of previous generations, acid rain may be partly responsible.
Beyond their effects on living creatures, acids also react with other dangerous chemicals, resulting in indirect harm to species. High acidity reacts with some natural substances, such as aluminum, in a way that "frees" their toxic forms into natural systems. Pollutants carried in acid rain both deposit mercury in ecosystems and amplify its effects. For instance, when surface water becomes acidic and mercury continues to be deposited, fish accumulate mercury faster. This chemical build-up makes the fish unsafe for humans, particularly women and children, to eat in substantial quantities. In New York State, 84 water bodies have fish consumption advisories because of mercury pollution.
Among New York State's distinctive natural resources, the Adirondack region has suffered the most from acid rain. Whereas many areas have limestone deposits or soils that neutralize the acid, the Adirondacks have a low buffering capacity. As such, the Adirondacks are an indicator of acid rain's most drastic effects, acting as the nation's proverbial "canary in a coal mine."
Although acid rain has stressed Adirondack forests as a whole, two species have experienced particularly heavy losses: red spruce and sugar maple. In high altitudes, the red spruce is often surrounded by acidic clouds, which some researchers believe may lead to increased winter injury. In the 1970s and 1980s, 50 percent of canopy red spruce trees in the High Peaks and other high elevation regions died or were damaged. Likewise, sugar maple, the basis for the maple syrup industry, suffered die-offs in the 1980s. While the soil acidity has begun to decline, these damaged forests stand testament to acid rain's destructive power.
Acid rain has also ravaged Adirondack lakes. Normally, lakes can neutralize incoming acid to levels that fish can tolerate. But in the Adirondacks, 26 percent of lakes cannot lower their acidity to a tolerable level and 70 percent have the potential to become too acidic at certain times of the year. Also, 16 out of 48 Adirondack lakes that scientists surveyed have aluminum levels too high for many juvenile fish. Even if adult fish can live in these lakes, the populations cannot sustain themselves if the juveniles do not survive.
In 1984, taking notice of the Adirondack and Catskill mountains' sensitivity to acid rain, New York State passed the first law in the nation to control these emissions, the State Acid Deposition Control Act. As a result of New York's advocacy, Congress amended the Clean Air Act in 1990 to require nationwide controls on SO2 and NO x. As a result of these laws, national SO2 emissions levels peaked in 1973 and have continued to decline. Likewise, NOx emissions were at their highest in 1990 and have declined since.
Implementation of air pollution laws have lightened the burden on Adirondack lakes, which have started to show signs of recovery. Over the last 20 years, both the lakes and atmosphere have become far less acidic. The areas that were sensitive to acidity are resurging, suggesting that the whole region may undergo revitalization. The lakes are gaining back their ability to neutralize acid and the toxic aluminum is reverting back to forms which are less dangerous.
However, the policy work on acid rain is far from over. Lakes that are only seasonally acidic can take anywhere from a few years to up to half a century to regain their ability to neutralize acid. Lakes that are acidic year-round may take even longer, from 25 to 100 years to recover. Once a lake has chemically recovered, it will then take additional time for the wildlife to return. For instance, some fish populations may recuperate within a decade of full chemical recovery, or even faster if they are restocked.
New York State continues to be a leader in fighting the pollutants that lead to acid rain. The Acid Deposition Reduction Program began in 2004, aiming to reduce emissions from fossil-fuel power plants. A cap and trade program, it distributes a certain number of pollutant "allowances" to electric generation companies in the state. The companies can then trade these allowances between them like money. This system allows the power plants with the best technology to improve their facilities first. As the program continues, the state will distribute fewer allowances over time, further reducing emissions.
This cap and trade program, combined with litigation against electric generators, has produced significant results in New York. In 2007, statewide SO2 emissions were down to one-third of those in 2003, an 80 percent decrease since 1990. This decrease of 35,000 tons per year of SO2 is equivalent to eliminating all of the emissions caused by New Yorkers who use oil to heat their homes. Similarly, NOx emissions in 2006 are down almost 50 percent since 2003. This yearly reduction of 6,000 tons of NO x equals taking 300,000 cars off of the roads each year.
Inspired by New York and other leading states, the federal government has further raised its own standards. The Clean Air Interstate Rule was adopted in 2005 and applies to all states east of the Rocky Mountains. It uses a similar cap and trade structure, but will catch up with the state standards in 2009 and exceed them in the future.
Despite the vast progress, experts say that we need further reductions to allow ecosystems to recover. "What we've done matters. But we still need to do more," said Rob Sliwinski, Director of Air Quality Planning in the Division of Air Resources in the Department for Environmental Conservation.
Citizens can help continue the recovery by taking some basic steps. Since power plants emit many of the pollutants that contribute to acid rain, conserving electricity is essential. "Pollution prevention is easier than pollution control," said Sliwinski. Also, cars are a major producer of the emissions that lead to acid rain. Reducing your mileage, regularly tuning-up your automobile, and buying cars with strict pollution controls will further reduce your personal impact.
Despite acid rain's past decimation of some of New York's forests and lakes, the data on declining pollution provides an optimistic outlook. For anyone who loves the Adirondack Park, these numbers should be both a cause for celebration and a motivation to continue our protection of this unique region.
Shannon Brescher Shea is a staff writer for Conservationist and a graduate of Cornell University's Natural Resources/ Communication programs.
NOTE: Much of the scientific data in this article was drawn from Karen Roy (NYSDEC) and Charles Driscoll's (Syracuse University) research. Together with Jerry Jenkins (Wildlife Conservation Society) and Christopher Buerkett (Adirondack Lakes Survey Corporation), they have written Acid Rain in the Adirondacks: An Environmental History, published in 2007 by Cornell University Press. The most recent results and scientific findings are available at: www.adirondacklakessurvey.org.
Learning About Acid Rain
DEC scientists use pH testing to measure the acidity of a stream, lake or area of soil. Through this assessment, they determine how much acid rain has affected an area.
pH is a chemical indicator that measures how many hydrogen ions (H+) are present in a solution. The pH scale runs from 0 to 14, with 0 being the most acidic and 14 being the most basic. While pure water has a neutral pH of 7 and unpolluted rainwater has a pH of 5.6, unpolluted water bodies usually range in pH between 6 and 8.
Although scientists use a more accurate probe and meter, students of all ages can use inexpensive litmus strips to test pH. Litmus paper is specially formulated to change color when dipped in liquid. By comparing the color to a chart included in the packaging, you can determine the liquid's acidity.
When experimenting with litmus strips, try dipping them in a number of different substances. Even household goods have a range of pH levels, from lemon juice at a pH of 3 to baking soda at a pH of 9. Once you have tried testing some common products, bring the litmus strips outside and test the pH of different types of water. Distilled, tap, rain and stream water should all vary in their acidity.
Litmus paper is available from a number of sources, both online and in stores. Many classroom suppliers sell pH strips within kits for exploring acids and bases. Also, pH strips are often included in swimming pool testing kits sold at hardware stores.
No matter what you choose to test, measuring pH is a fun, hands-on way to learn about acidity in the natural world.
Saving Adirondack Fisheries
Acid deposition caused many Adirondack lakes and ponds to become fishless. To combat this problem and reestablish native brook trout populations in some of these decimated waters, NYSDEC Bureau of Fisheries started a liming program. Beginning in 1959, DEC began to apply agricultural lime to certain ponds to raise their pH. Typically used to enhance farm soil, agricultural lime temporarily improves the water's ability to buffer acid deposition, raising the pH to a level that fish can tolerate. Today's liming program includes 37 waters across the Adirondacks. Each year, researchers take water samples from the ponds to monitor their pH and acid-neutralizing capacity (ANC). If a pond's water has a pH below 6 and an ANC below 20, it is scheduled for a liming treatment. Treatments, which last between 5 and 15 years, are often done in the winter by spreading lime across the pond's frozen surface. These treatments are only a stop-gap measure while we work to limit acid precipitation. However, without liming, these waters would remain fishless. Liming also benefits a wide range of native fauna and flora, including many sensitive species such as loons and otters.
Acid Rain & Greenhouse Gas
Although acid precipitation and greenhouse gases may result from the same pollutant sources, such as cars, power plants, and factories, they involve different atmospheric levels and natural processes. Acid precipitation forms in the lower levels of the atmosphere when sulfur dioxide and nitrogen oxides combine with moisture. The resulting acid precipitation then falls to the ground, changing the water and soil chemistry in a specific area. Greenhouse gases, such as carbon dioxide, are direct by-products of industrialization and collect at a much higher point in the atmosphere. There, they hold heat in, intensifying the earth's greenhouse effect. This interaction causes the earth's climate to warm more than it would otherwise, influencing worldwide temperatures and precipitation patterns.