Integrated Assessment of Artisanal and Small-Scale Gold Mining in Ghana—Part 2: Natural Sciences Review

This paper is one of three synthesis documents produced via an integrated assessment (IA) that aims to increase understanding of artisanal and small-scale gold mining (ASGM) in Ghana. Given the complexities surrounding ASGM, an integrated assessment (IA) framework was utilized to analyze socio-economic, health, and environmental data, and co-develop evidence-based responses with stakeholders. This paper focuses on the causes, status, trends, and consequences of ecological issues related to ASGM activity in Ghana. It reviews dozens of studies and thousands of samples to document evidence of heavy metals contamination in ecological media across Ghana. Soil and water mercury concentrations were generally lower than guideline values, but sediment mercury concentrations surpassed guideline values in 64% of samples. Arsenic, cadmium, and lead exceeded guideline values in 67%, 17%, and 24% of water samples, respectively. Other water quality parameters near ASGM sites show impairment, with some samples exceeding guidelines for acidity, turbidity, and nitrates. Additional ASGM-related stressors on environmental quality and ecosystem services include deforestation, land degradation, biodiversity loss, legacy contamination, and potential linkages to climate change. Though more research is needed to further elucidate the long-term impacts of ASGM on the environment, the plausible consequences of ecological damages should guide policies and actions to address the unique challenges posed by ASGM.