Artisanal and small-scale gold mining is a vital source of income, but it is also very dangerous because miners use toxic mercury to separate gold from ore. Mercury is a shiny liquid metal that attacks the nervous system. Exposure can cause lifelong disability and is particularly harmful to children. Most consumers don't know where the gold in their products comes from or how it's extracted.
Gold mining is one of the most destructive industries in the world. It can displace communities, contaminate drinking water, harm workers and destroy pristine environments. It contaminates water and land with mercury and cyanide, endangering the health of people and ecosystems. Producing gold just for one wedding ring generates 20 tons of waste.
While the list of retailers aligned in their opposition to 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 that lie 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. .
Cyanide, mercury and other toxic substances are regularly released into the environment due to the extraction of dirty gold. Producing a pound of gold requires about 6 pounds of mercury. Since at least 50 percent of the mercury used in these operations is lost to the environment, we estimate that artisanal gold mining in Peru alone releases nearly 50,000 pounds of mercury per year. These bacteria help the enrichment of metals in the water of gold minerals and mines, in a solubilization process called biolealization.
Mercury is the product of hundreds of illegal small-scale gold mines and is leaving its poisonous mark on forest fauna. Several studies also investigated bacterial diversity in gold mines using techniques independent of culture based on the identification of the bacterial 16srRNA gene. Gold mining in South Africa over the centuries has led to the accumulation of thousands of bulky tailings landfills that are scattered throughout the country, which can have a major negative impact on the environment. Tailings are a mixture of finely ground rock that remains after the recovery of the precious mineral and water used in processing.
To develop an efficient bioremediation approach for gold mine waste, a better understanding of bacterial interactions with metals in this environment is required. Gold nuggets are popular with collectors, but are rare; most gold is found in the form of tiny particles buried in gold ore. Gold mining is also responsible for releasing large amounts of mercury into the air and water of the Amazon. However, extracting just one ounce of gold from the ore can cause 20 tons of solid waste and significant mercury and cyanide contamination.
Environmental pollution from gold mines is mainly associated with the release of harmful elements from tailings and other waste from mines. For every gram of gold produced, artisanal gold miners release about two grams of mercury into the environment. The extraction methods used by these operations today are not drastically different from the processes that miners employed in the California gold rush of the mid-19th century. Gold mining alters the landscape, the water table, geological stability and surrounding ecosystems because large quantities of ore have to be extracted to obtain small quantities of gold.