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. Many gold mines dump their toxic waste directly into natural bodies of water.
Mining companies around the world are estimated to be responsible for eliminating at least 180 million tons of toxic waste from rivers, lakes and oceans every year, destroying corals, marine life and freshwater ecosystems in the process. To develop an efficient bioremediation approach for gold mine waste, a better understanding of bacterial interactions with metals in this environment is required. Another source of environmental pollution from gold mines are chemicals used in gold processing. Zinc is also found in gold ore deposits in the form of sphalerite (ZnS), which is often associated with galena.
Gold mining can be open pit or deep well mixed with other HMs, such as copper (Cu), silver (Ag) and lead (Pb). There is a clean, non-toxic solution available on the market that can recover gold without toxic chemicals. The first step is to address the root cause of the problem, namely, to eliminate the lethal chemicals involved in gold processing. High levels of HM in gold mine waste greatly affect the diversity, size of the population and the general activity of bacteria.
The ore collected from gold mines is dissolved using a non-toxic reagent before the gold is recovered from the ore using polymer. Clear advantages of bioleaching gold compared to traditional physicochemical methods have been described. The biooxidation of sulfide contained in refractory gold ores improves the release of gold particles from the sulfide matrix, making gold susceptible to dissolution using leaching agents such as cyanide. These bacteria help the enrichment of metals in the water of gold minerals and mines, in a solubilization process called biolealization.
Taking into account the extreme conditions found in gold mine tailings, it is possible that in the future the way in which resistant bacteria interact with HM in this environment will be discussed. Mining, mineral processing and metallurgical extraction are the three main activities of the gold mining industries that produce waste. The use of bacteria in gold mining, known as biomining, has received considerable attention due to the potential roles played by these bacteria in recovering gold from gold-containing minerals. The sulfidic nature of many gold deposits makes it difficult for leaching agents to be accessible, but the activity of several acidophilic and chemolithotrophic bacteria oxidizing iron and sulfur has been reported to help the oxidation of the sulfide matrix.
Gold mining, a major source of air pollution, releases approximately 400 metric tons of elemental mercury into the air each year, that is, approximately 2 grams of mercury for each gold wedding ring.