Queen's University

School of Environmental Studies
Dept. of Geological Sciences & Geological Engineering

Biogeochemical cycling of mercury associated with mercury use in Artisanal Small-scale Gold Mining (ASGM)

Emissions of mercury from ASGM activities are now the largest single emitter of mercury to the atmosphere globally. However, there are major shortcomings in our knowledge of the biogeochemical cycling and impacts of this mercury relating largely to the informal, non-standardized, and often illegal nature of these activities. Compounding this are land-use changes associated with these activities (deforestation and river erosion/ sedimentation) and their prominence in more remote, tropical ecosystems that are typically less studied than temperate terrestrial systems. In addition, there are complicated social dynamics in regions with ASGM activities, for instance: (i) displacement of and health impacts on Indigenous peoples, (ii) balancing health risks with income, (iii) economic migration, (iii) prosperity-based inflation, (iv) increased criminality, and (v) trust and investment impediments to alternative, cleaner gold extraction methods.

FEWA Lab research into ASGM activities will focus on combining these different physical and social science considerations by developing research that seeks not only scientific data on mercury biogeochemistry, but also impact, capacity building (technology and training transfer), and collaborations with these communities. One such study will address the impact of ASGM mercury  emissions on local agriculture and exploring this as a human-exposure pathway for mercury in ASGM affected areas. Quantifying mercury usage and emissions remains one of the greatest challenges associated with ASGM activities and my research will seek to develop top-down (from measurement to emissions) methods that combine low-tech monitoring techniques (i.e., passive sampling, dendrochronology) with models in an attempt to assess the extent of mercury usage. We are also interested in examining the potentially compounding effects other environmental impacts of ASGM (i.e., deforestation and increased sediment loads) have on the transport, fate, and toxicity (increase methyl-mercury production) of mercury in these impacted systems.

Figure: Technology and training transfer. Dr. David McLagan providing sampling method training to one of the employees of CINCIA in Madre de Dios, Peru.

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