Coal and Climate Change
Coal use, from its extract to waste product disposal, presents threats to water quality. Coal mining and use in Tennessee has lasting effects that impact water quality for residents.
Coal mining has a long history in Appalachia and in Tennessee specifically. Since the late 1800s, bituminous coal mining operations have taken place in Tennessee. In the early period, coal mining was carried out by the deep mining method. In deep mining, operators created a shaft into the ground or mountainside to mine underground.
Coal mining pollutes streams in Tennessee. TDEC has listed more than 100 stream miles, of assessed streams, as polluted as a result of past and present mining in Campbell, Claiborne, Anderson, and Scott Counties. This figure does not include destroyed, relocated, or polluted small headwater streams. It is documented that existing coal mining operations threaten water quality. The U.S. Forest Service explains that coal mining can pollute aquatic environments by producing sediment, lowering pH, introducing toxic heavy metals, and altering stream channels and flow. Coal-impaired Tennessee streams suffer from synergistic effects of multiple pollutants and do not meet state criteria for biological integrity. Even though coal mining has declined significantly, impacts to water still occur.
Abandoned mine sites threaten water quality with acid mine drainage. Researchers have determined that acid mine drainage is the result of elevated concentrations of dissolved and particulate iron and dissolved sulfate produced by the oxidation of pyrite. This process can make water as acidic as vinegar and cause water to turn orange due to iron precipitation. Acidic mine drainage includes toxic materials such as selenium, manganese, acids, and mercury. Sediment also pollutes waterways. The resulting aquatic conditions are threatening to drinking water and aquatic biodiversity.
Coal combustion residuals, commonly referred to as coal ash, are byproducts from burning coal. Coal-fired electric generating units produce coal ash while operating power plants. Unfortunately, coal ash has the potential to contaminate waterways. Coal ash contains harmful substances including mercury, cadmium, and arsenic. Coal ash impoundments adjacent to lakes, streams, and rivers may leach coal ash and/or its contaminants into water.
The Disposal of Coal Combustion Residuals from Electric Utilities Rule was finalized in 2015. The rule sets national minimum criteria for existing and new CCR landfills.