Abandoned mine drainage
Abandoned mine drainage (AMD), is water that has been polluted through contact with the mining industry, most often through coal mining. This type of pollution is common in states where there was a great deal of mining activity. The remaining waste rock, mine pits and other debris can cause environmental harm as t react chemically with the surrounding water supplies and oxygen. Because the metals and other debris that remain from mining differ widely, it can be difficult for government agencies to know how to deal with the environmental impacts. According to the U.S. Environmental Protection Agency (EPA), the most common type of AMD is acid mine drainage.
Acid mine drainage
Acid mine drainage is acidic water that is polluted with heavy metals. The acidic water in acid mine drainage is formed as surface water chemically reacts with subsurface water that has been contaminated with sulfur from minerals under the earth's surface. The heavy metals in acid mine drainage can be leached from rocks because of the acid in the water. It is these heavy metals that pose a danger to human health and the environment. It has been estimated by researchers and government agencies, that in the Eastern U.S. over 4,300 miles of streams are affected by acid mine drainage from coal mines. In the Western U.S. the U.S. Forest Services estimates 5,000 to 10,000 miles of steams have been impacted from coal mine acid drainage.