May 17 2009
Everything is connected to everything else. What happens when one part gets damaged?
When this spring-fed fountain was built years ago at Jennings in Butler County the water was clear and clean. Now, like many waterways in southwestern Pennsylvania, the water is orange and smells like sulfur, a victim of acid mine drainage.
Acid mine drainage (AMD) is a coal country problem that’s especially acute in southwestern Pennsylvania, West Virginia and southeastern Ohio. It comes from primarily two sources: abandoned coal mines and mine tailing piles. While a coal mine is active, the mine operator pumps water away from the coal but after the mine closes or the mining company goes defunct the mine fills with water and the chemical reactions begin. Nearby, coal waste piles are left exposed to rain and runoff. Soon the water supply is orange and the streams go dead.
In both cases the water is reacting with pyrite, a ferrous mineral found with our coal, that forms sulfuric acid and dissolved iron. The process is exacerbated if the pyrite was crushed, as it is during mining, and if the water contains an iron-oxidizing bacteria called thiobacillus ferrooxidans.
As the water becomes more acidic it dissolves heavy metals including lead and mercury. These precipitate out on stream bottoms when cleaner water joins the flow.
It’s a nasty brew. Aquatic insects and invertebrates die, fish disappear and the birds who depend on both abandon the waterway.
Even warblers are affected by dead water. The Louisiana waterthrush eats aquatic macroinvertebrates (clams, snails, worms and nymphs) and cannot thrive in the presence of acid mine drainage. Powdermill Nature Reserve conducted a study in the late 1990s which showed a dramatic difference in Louisiana waterthrush nesting success on two adjacent streams: Powdermill Run, a clean stream, and Laurel Run, polluted with acid mine drainage. The clean stream hosted nearly three times the number of nesting pairs.
Throughout our area many AMD sites are being cleaned up using passive treatment with constructed ponds and wetlands. Some of these sites are visitor-oriented where you can learn how it works. There is one such site at Jennings Environmental Education Center and another at the Art and AMD project in Vintondale. Unfortunately AMD treatment costs money to construct and maintain so many waterways continue to suffer.
I hope that money will become available in the future to clean up more AMD sites. Not only will we benefit from it but the herons, kingfishers and Louisiana waterthrushes will thank us.
(photo by Kate St. John)