La présentation sera en français, les diapositives en anglais

Abstract
Over the past few decades, artisanal and small-scale gold mining (ASGM) has expanded rapidly in West Africa, driven by rising gold prices. This gold mining has thus spread very quickly in Guinea, where gold ore is traditionally extracted mainly by men at mining sites, then transported to villages where women recover the gold, primarily through amalgamation with mercury (Hg).
In this study, we analysed the speciation of Hg [total Hg (THg), methylmercury (MeHg) and elemental Hg (Hg0)] in soil profiles from two gold mining sites and mining villages. The results showed that mercury remains mainly concentrated near the surface, with higher concentrations in the centre of the villages (up to 10 μg g⁻¹ THg) than at the mining sites (up to 0.6 μg g⁻¹ THg). Elemental mercury follows the same trend, with higher concentrations in the villages (up to 7.5 μg g⁻¹ Hg0) than in the mines (0.2 μg g⁻¹ Hg0). High concentrations of THg (up to 7.5 ng L⁻¹ THg) were found in village well water, indicating that these wells have been contaminated by the deposition of eroded soil particles.
We also estimated the mercury stock, which was found to be higher in the villages (up to 2.7 g/m²) than in the mines, with elemental mercury accounting for 60 to 70 per cent of the total mercury. Given the hot, dry climate, we estimated that the potential re-emission of this Hg0 could take between 35 and 4,500 years.
This study highlights that gold extraction methods in Guinea cause significant mercury pollution beyond the mining areas. The direct burning of mercury amalgams in domestic fireplaces, as well as the potential re-release of mercury from the surface soil in villages, underscore the potential dangers of chronic exposure for local communities. This highlights the urgent need to raise awareness amongst mining communities of the consequences of their traditional mercury-based methods.

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