A sodium cyanide solution is commonly used to leach gold from the mineral. Cyanide dissolves gold from the ore in the solution as it drains through the heap. The small-scale artisanal gold mining (ASGM) sector exposes miners to toxic mercury when they use the chemical to extract gold from the ore. However, with appropriate market policies and incentives, the ASGM presents an opportunity to combat the use and contamination of mercury, protecting the health of miners and the environment at the same time.
Non-essential HMs, such as Ag, As, Cd, Pb and Hg, are of no biological importance to living organisms and are very toxic when found in the ecosystem. Thornton, “Chemical partitioning of trace and principal elements in soils contaminated by mining and smelting activities, Applied Geochemistry, vol. Gold mining has played an enormous role in the growth and sustenance of the economies of many countries, with an enormous price to pay in the form of generating and releasing toxic waste products that have a profound impact on the ecosystem. These results indicate that the area around the washing or grinding of gold could be the main source of contamination by As and other toxic elements (TE) in surface soil samples.
Carling GT, Ximena DX, Ponce M, Lester PL, Nasimba L, Pazmino E, Rudd A, Merugu S, Fernandez DP, Gale BK, Johnson WP (201) Concentrations of particles and dissolved trace elements in three rivers in southern Ecuador affected by artisanal gold mining. It is found in minerals that contain gold as an isometric trace element in sphalerite and its concentration depends on the concentration of sphalerite in the mineral deposit. The highest values of Cu, As and Pb were found in the vicinity of the gold washing site, indicating that the surface soils of the mining area were highly enriched with these elements. Chatterjee M, Silva FEV, Sarkar SK et al (200) Distribution and possible source of trace elements in the sediment cores of a tropical macrotidal estuary and their ecotoxicological importance.
In addition, the highest values in the gold washing zone were those of Cu, As and Pb, indicating that the soils surrounding the mining area were highly enriched by these elements. Environmental pollution from gold mines is mainly associated with the release of harmful elements from tailings and other waste from mines. A preliminary assessment has been determined of the contamination by toxic elements caused by artisanal and small-scale gold mining in the Bonsa River in Ghana, as well as of the influence of the concentration of TOC and SO42 on these traces in the sediment. In the Boroo area (Mongolia), which is currently one of the active sites for small-scale gold mining, analyses of toxic pollutants in soils, river water and human hair have focused mainly on the determination of mercury since 1994 (JICA project report).
This mechanism is subject to environmental modification, availability and toxicity of the metal, to intrinsic biochemical and structural properties, and to genetic and physiological adaptation. In biomethylation, the transformation of HM, such as Hg, As, Cd and Pb, increases their mobility and their suitability to participate in processes that lead to the reduction of their toxicities. High concentrations of As and Pb are a cause for serious concern because they are carcinogenic, toxic at low concentrations and bioaccumulative in organisms.