Radio-nuclides occur naturally in the environment and little is known about the health effects of long-term exposure to low levels. When radio-nuclides are present in high concentrations they can negatively impact biota through mutagenic and carcinogenic effects, given sufficient doses over a period of time. Uptake of radio-active particles may be direct, through ingestion, or indirect through the food chain. As there is no basin-wide radio-nuclide monitoring programme, the magnitude and significance of the problem is not known, especially with relation to transboundary effects.
The causes of radio-nuclide contamination (high concentrations) in water can mainly be ascribed to a lack of adequate environmental management and control in the mines (particularly gold and uranium). Radio-nuclides can become airborn when tailings ponds are not properly contained. They can also leach into the soil and the groundwater, and are associated with Acid Mine Drainage.
Location of Gold Mines in the Limpopo River basin.
Source: Ashton et al. 2001
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Radio-nuclides can also be found in industrial sites where radio-active materials may be produced or stored, such as the Pelindaba experimental reactors in South Africa (Ashton et al. 2001).
Impacts of Radioactivity from Mining Activities
Impacts from radioactivity include: atmospheric impacts (radionuclide-contaminated dust); terrestrial environmental impacts (e.g., soil contamination, aquatic sediment contamination and bioaccumulation of radionuclides in ecosystems) and human health impacts (genetic mutations, radiation sickness and mental retardation at high levels).
Source: Government of North West Province 2002
