Informal Gold Mining Research Articles

Informal gold mining and national development: The case of Mongolia

Informal gold mining is being increasingly recognised internationally as a major phenomenon, with an estimated 13 million active participants worldwide. It is a recent activity in modern Mongolia1 and this paper discusses its development and prospects in relation to some of the major forces that have affected society since transition to a market economy began in 1990: namely the privatisation of pastoral and arable agriculture; privatisation of industries and services; ever widening and deepening poverty; emergence of the informal sector; and government attempts to develop a modern mining industry. The paper illustrates some of the limitations to planning, particularly in transitional economies; but also the potential benefits of quickly identifying unanticipated changes and then planning for them. It also illustrates the large and sometimes unrecognised impacts, both socio-economic and environmental, that such changes can have on countries with small populations.

Methylmercury neurotoxicity in Amazonian children downstream from gold mining.

In widespread informal gold mining in the Amazon Basin, mercury is used to capture the gold particles as amalgam. Releases of mercury to the environment have resulted in the contamination of freshwater fish with methylmercury. In four comparable Amazonian communities, we examined 351 of 420 eligible children between 7 and 12 years of age. In three Tapajós villages with the highest exposures, more than 80% of 246 children had hair-mercury concentrations above 10 microg/g, a limit above which adverse effects on brain development are likely to occur. Neuropsychological tests of motor function, attention, and visuospatial performance showed decrements associated with the hair-mercury concentrations. Especially on the Santa Ana form board and the Stanford-Binet copying tests, similar associations were also apparent in the 105 children from the village with the lowest exposures, where all but two children had hair-mercury concentrations below 10 microg/g. Although average exposure levels may not have changed during recent years, prenatal exposure levels are unknown, and exact dose relationships cannot be generated from this cross-sectional study. However, the current mercury pollution seems sufficiently severe to cause adverse effects on brain development.

Emission and stability of mercury in the Amazon

ercury pollution in the Amazon represents one of the most serious environmental issues faced by mankind today. From 70 to 1701 of Hg are discharged annually into the Amazon environment from informal gold mining operations. Vegetation fires are also a major source of Hg emissions with the form being more reactive than that from mining activities. The extent of biota contamination is also more widespread. Mercury must be rendered soluble and then converted into methylmercury in order to accumulate in the food-chain. Generally, it is regarded that oxidation of Hg must occur to produce significant dissolution. In this work, we examine the stability of metallic Hg in aquatic environments. In contact with organic acids, evidence of Hg-organic complex formation has been found from both thermodynamic analysis and electrochemical experiments. Although methylation of these soluble species is not fully understood, formation of such complexes in dark-water rivers must contribute to increased bioavailability.