Artisanal mining of gold with mercury in Ghana

Abstract

The paper examines the environmental impact of artisanal mining of gold with mercury (Hg) in Ghana. In spite of its positive socioeconomic contributions, it is well known that artisanal mining of gold contributes in no small measure to land degradation, loss of biodiversity and natural resources, deforestation, water pollution, etc. In Ghana, these environmental problems remain poorly studied. In the case of Hg pollution, caused by gold extraction using the amalgamation process, total Hg levels in different environmental compartments of the gold-mining-impacted Pra River basin in southwestern Ghana were determined using the latest sampling and analytical techniques. Artisanal gold mining activities in the Pra River basin are on the increase and even though Hg levels determined in water, soil, and sediments were below WHO safe guideline values, the current state of affairs poses a serious environmental threat. However, the majority of the populace, particularly those engaged in gold mining, are unaware of the dangers posed by the use of Hg in mining operations. This paper seeks to draw the attention of Ghanaians (as well as their foreign counterparts) to the need to take up the mantle in changing the general patterns of environmental damage caused by the artisanal gold miners. The need to regularize artisanal gold mining is long overdue. A legal regime for mines of every size, leading to a transformation of the artisanal mining sector into a legal, regulated industry, will help minimize the impact on the environment.

Contamination from mercury and other heavy metals in a mining district in Ghana: discerning recent trends from sediment core analysis

“…Mercury concentrations however marginally declined during this period, such that the least concentration was measured in the upper layers of the sediment core. This finding is consistent with recent decline in sediment Hg levels in Lake Bosomtwe in Ghana (Poste et al 2012), but quite at variance with reported illicit application of Hg by illegal small-scale miners (Donkor et al 2006b;Hilson et al 2007). Two main factors may have contributed to the decreasing trend in Hg concentration.…”

Assessments of the transmission of Onchocerca volvulus by Simulium sanctipauli in the Upper Denkyira District, Ghana, and the intermittent disappearance of the vector

“…There is a large-scale open-pit and underground gold mine at Obuasi near the River Jimi (which a tributary of the river Ofin upstream of the study area), but mining the rivers and river banks is usually carried out by artisanal (small-scale) miners. The artisanal sector was effectively legalized in 1989 and now represents approximately 10 % of Ghanaian gold production (Donkor et al 2006). The sector works mostly alluvial gold deposits in flood plains, along river banks, and by river dredging.…”

Assessment of Trace Elements Levels in Sediment and Water in Some Artisanal and Small-Scale Mining (ASM) Localities in Ghana

“…The frequent use of Hg by artisanal gold miners to extract the gold from the ore (Donkor et al, 2006), the occurrence of As as an impurity in gold ore (Eisler, 2004) and Cu's association with gold mining waste (Ferreira Da Silva et al, 2004) might have led to the high contamination of the elements in the sediments. Table 5 indicates the concentrations of Cd, Pb, Fe, Zn, Mn, Cu, and Hg and As in water samples of the four artisanal mining localities.…”