terence mccarthy, geology professor at the university of witwatersrand confirms that the local groundwater is riddled with toxins. he predicts that millions of south africans will soon be dealing with a contaminated water supply. >> the areas where most of the coal-mining is taking place are our primary food producing regions and we are impacting on those. moreover, coal is not only mined but also burned here in mpumalanga. eleven huge, smoke-belching coal-fired power plants darken the skies. pollutants react with water molecules in the atmosphere to produce acid rain. scientists fear that heavy metals from the coal industry will soon spread throughout the regional water cycle. >> we are destroying the ecology of our main river system, and there is nothing we can do about it except stop mining. >> but coal deposits are one of the rainbow nation's main resources. and right now, its fast-growing economy needs more energy than ever. south africa ranks twelfth on the list of the world's biggest greenhouse gas emitters. coal-fired power plants produce 71 percent of the country's electricity. th