A preliminary study of the relative contributions of diffuse and point sources of pollution arising from gold mining activity in a Witwatersrand goldfield

摘要

Gold mining on the Witwatersrand, South Africa, has generated considerable wealth for the country, but has also resulted in several environmental problems, notably pollution of surface and underground water sources. The ores contain pyrite, minor heavy metal sulphides and uranium minerals, and oxidation of these minerals has led to contamination of groundwater beneath tailings dumps (diffuse sources) and water pumped from the mines (point sources). A study of a reach of the Blesbok stream where both diffuse and point pollution sources occur has revealed that these two sources contribute similar amounts to the total pollution load. However, the diffuse source water has not been treated, and appears to contribute the bulk of the heavy metals.