According to the EPA Toxic Substances Inventory, gold mines are one of the main sources of toxic mercury air pollution in the U.S. UU. While the list of retailers who oppose dirty gold continues to grow, most gold is still quite dirty. Most of the world's gold is extracted from open pit mines, where huge volumes of land are extracted and processed for trace elements.
Earthworks estimates that, to produce enough raw gold to make a single ring, 20 tons of rock and soil are extracted and discarded. Much of this waste contains mercury and cyanide, which are used to extract gold from rock. The resulting erosion clogs streams and rivers and can eventually contaminate marine ecosystems deep below the mine. Exposing the depths of the earth to air and water also causes chemical reactions that produce sulfuric acid, which can seep into drainage systems.
Air quality is also compromised by gold mining, which releases hundreds of tons of elemental mercury into the air every year. Fact sheet summarizing the main points of national standards for the emission of hazardous air pollutants for gold ore processing and production facilities, the seventh largest source of mercury emission into the atmosphere in the United States. Although the two gold mines closed in 1998, water recovery and treatment efforts continue to cost state taxpayers millions of dollars. Most forms of gold mining involve moving large amounts of soil and rock, which can be detrimental to the surrounding wildlife habitat.
Mining, mineral processing and metallurgical extraction are the three main activities of the gold mining industries that produce waste. While the EPA strives to remedy and restore nearly countless mines in the United States, and as activists work to stop the wave of demand in the gold industry, efforts are being made to develop more open pit mines. The level of tolerance shown by bacteria found in various environments contaminated with tailings from gold mines is determined by the concentration of HM present in those environments. Clear advantages of bioleaching gold compared to traditional physicochemical methods have been described.
A major investor in the project withdrew late last year, and the jewelry industry, which uses about half of all the gold mined each year, has expressed opposition to the project. To develop an efficient bioremediation approach for gold mine waste, a better understanding of bacterial interactions with metals in this environment is required. Tailings are the main wastes produced by gold mining and contain large quantities of heavy metals (HM). The high value of gold has made it the primary objective of massive industrial mining operations designed to extract the ore as efficiently as possible.
In addition, mercury used in artisanal and small-scale gold mining operations can become airborne and pollute both air and water. Several studies also investigated bacterial diversity in gold mines using independent culture techniques based on the identification of the bacterial 16srRNA gene.