ADDRESSING ENVIRONMENTAL HEALTH IMPACTS OF MAJOR AND ABANDONED MINES IN SUB-SAHARAN AFRICA

Since 2011, UNESCO and the Swedish International Development Agency (SIDA) have embarked on promoting a flagship International Geoscience Programme (IGCP), involving a group of scientists from Africa and Europe, who are currently investigating health impacts on agro-ecosystems due to the release of potentially harmful elements (PHEs) from abandoned mines in Sub-Saharan Africa, under a collaborative mandate drawn between two IGCP sister projects, viz., IGCP-594 and IGCP-606.

This paper presents a detailed synthesis of the achievements of these projects so far, which include: (i) the near completion of reconnaissance mapping of abandoned mines in Nigeria and Zimbabwe; (ii) the identification of several mine sites which are sources of PHEs; (iii) experimental data on migration pathways and rate of uptake of specific toxic trace elements by plants and food crops; e.g., the content of metals and arsenic in tubers of cassava (Manihot esculenta) and some vegetable crops growing respectively, on contaminated and uncontaminated soils of the Zambian Copperbelt mining district has been determined, and dietary exposure to these elements evaluated; (iv) the obtention of preliminary results on the effectiveness of bentonite clay and fly ash for remediating the intractable problem of Acid Mine Drainage (AMD), and (v) through the ‘outreach and educational research’ component of these projects, awareness (science-based knowledge and advices) creation in governments, the private sector and the public on the impact of abandoned and derelict mines on the environment, ecosystem services and health.

The two projects (IGCP-594 and IGCP-606) which would run till the end of 2014 continue to provide crucial scientific knowledge that would contribute to understanding of the cycling of pollutants from abandoned mines in soils, water and vegetation, and the impact on the food chain. Development of appropriate technologies to mitigate environmental risk associated with mining activities is also at the heart of these projects. Finally, the results of these projects will be used in the formulation of environmental norms in individual Sub-Saharan African countries, and will improve the efficiency of governments in addressing the challenges related to the adverse effects of abandoned mines.