Modelling mercury concentration in Ghanaian soil

Area of Science:

• Environmental Science
• Geochemistry
• Atmospheric Chemistry

Background:

• Artisanal small-scale gold mining (ASGM) is a primary global source of anthropogenic mercury pollution.
• Ghana possesses a substantial ASGM sector, contributing significantly to mercury release into the environment.

Purpose of the Study:

• To quantify mercury pools and fluxes in Ghana's ASGM sector.
• To develop a model for assessing mercury's regional increase in soils and water.
• To simulate future mercury contamination scenarios.

Main Methods:

• Estimated environmental mercury losses from ASGM.
• Utilized the Global Mercury Long-range Environmental Transport (GLEMOS) model for atmospheric deposition.
• Measured mercury concentrations in Ghanaian soils and water.
• Developed a 5x5 km resolution model for mercury in soils and water.

Main Results:

• Calibrated model accurately reproduced average soil mercury concentrations (0.0193 mg kg-1).
• Calculated a 22% average increase in soil mercury concentrations attributable to anthropogenic sources.
• Model showed good regional variation but underestimated hotspots in intense mining areas.

Conclusions:

• ASGM significantly elevates mercury levels in Ghana's soil and water.
• The developed model provides a valuable tool for assessing and predicting mercury contamination.
• Further refinement is needed to accurately capture mercury dynamics in high-intensity mining regions.