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Governments, international agencies, NGOs, and academics focus their projects’ objectives on monitoring mercury pollution in Artisanal Gold Mining (AGM). Rarely do these monitoring projects propose solutions to eliminate the use of mercury in AGM. Rather, they focus on the assessment of associated health or environmental impacts, demonstrations of cleaner techniques to extract gold and legal actions to formalize artisanal miners. Those approaches have not resulted in mercury reduction or elimination. This paper is an overview of the observations made by the first author in over 40 years of intensive research and field projects across 35 countries. To date, projects to eliminate mercury in gold processing have been predominantly unsuccessful mainly due to the lack of continuity and misplaced objectives. This paper reviews the attempts to eliminate mercury use in AGM. The co-existence of artisanal miners with the owners of the mineral titles (e.g. conventional mining companies) is successfully gaining momentum and has been witnessed in the field. Although different co-existence models are discussed in this review, we suggest a minor modification of the technique to improve the relationship between the miners and ore-processing companies. Essentially, our proposed co-existence model implies that the miners mine while the processors process.

Marine sediments from the Western and Eastern South Atlantic continental margins are used to reconstruct mercury (Hg) accumulation over the last glacial/interglacial cycle. Sediment core GL-1248, c...

The sediment core GL-1248, collected from the continental slope off northeastern Brazil, was used to reconstruct mercury (Hg) variations in NE South American continental margin and understand its variability in response to paleoclimate changes over the past 128 ka. Mercury concentrations in GL-1248 ranged between 14.95 and 69.43 ng/g, showing a glacial-interglacial pattern with higher (lower) concentrations in the glacial period (interglacial period). Parallel trends of Hg and XRF-Fe plots suggest that following atmospheric Hg deposition onto the continent, Hg is incorporated with Fe compounds before transportation and eventual immobilization at the NE Brazil continental slope. Peaks of Hg and Fe/Ca ratio peaks occurred concurrently during certain Heinrich Stadials, indicating that Hg is transported from the continent alongside fluvial sediments during periods of increased precipitation and erosion in NE Brazil continent. Mercury concentrations varied with periodicities of 56 ka and 900 yr suggesting glacial-interglacial changes and millennial-scale variability, respectively. Total Hg and total organic carbon are poorly correlated, although the latter likely influenced Hg sequestration into marine sediments during millennial-scale events between 60 ka and 30 ka. Altogether, our results suggest that the atmosphere is the primary source of Hg to GL-1248 and glacial-interglacial climate variations were the major determinant of atmospheric Hg deposition. Furthermore, increased precipitation during millennial-scale events played a secondary role by enhancing Hg transport to the continental slope of NE Brazil.