Does Every River Contain Gold?
Gold has been a popular and valuable component of jewelry for centuries. Gold is resistant to solvents, doesn't tarnish and is incredibly malleable, so it can be shaped with relative ease. Although its price fluctuates, gold regularly sells for more than $1,000 per ounce. Gold nuggets are popular among collectors but are rare; most gold is found as small particles buried in gold ore. Mining just an ounce of gold from ore can result in 20 tons of solid waste and significant mercury and cyanide contamination, according to Earthworks.
Some gold can be found by panning in rivers; heavy gold will remain in the pan, whereas lighter rocks and minerals float out. This small-scale form of gold mining has little effect on the body of water, but the large-scale practice of mining gold from ore can have tremendous negative effects on water quality. Gold typically sits in ore and sediment that contains toxins such as mercury. When rivers are dredged to mine large placer deposits of gold, these toxins float downstream and enter the food web, as they have done in California's South Yuba River, according to the U.S. Geological Survey.
Poisoned Drinking Water
Water contamination negatively affects not only wildlife populations but also human populations. Two open-pit gold mines in Montana closed in 1998 but continue to cost the state's taxpayers millions of dollars in reclamation and water-treatment efforts. Cyanide used at these mines to leach gold from ore resulted in such high levels of pollution that people cannot use nearby water resources until they have been subjected to extensive and expensive treatment and purification. Montana's Department of Environmental Quality expects reclamation efforts at the former mines to continue indefinitely.
Most forms of gold mining involve moving massive amounts of soil and rock, which can be detrimental to the surrounding wildlife habitat. The U.S. Environmental Protection Agency estimates that the development of a proposed gold and copper mine in Alaska's Bristol Bay would destroy at least 24 miles of streams that support the world's largest sockeye salmon fishery. Thousands of acres of wetlands and ponds would also be destroyed by the proposed mine's daily operations. Local communities depend heavily on this fishery and would be affected by this habitat destruction.
Risks and Accidents
Regular operations at gold mines adversely affect the environment in several ways. For example, the operation of large mining equipment requires fuel and results in the emission of greenhouse gases. However, potential mine accidents and leaks pose an even greater threat to nearby land and water resources. Contaminated tailings, or waste ore, need to be stored behind a dam; failure of such a structure would result in the widespread release of toxins. Mines must operate wastewater treatment plants to remove cyanide, mercury and other toxins from the water used for mining, and a treatment plant failure could also result in catastrophic contamination of the surrounding landscape.Source :https://sciencing.com/facts-5218981-effects-gold-mining-environment.html