Johannesburg, South Africa--The South African economy is substantially founded on gold. But now the ecological legacy of this great wealth is coming back to haunt the country and in particular its industrial capital of Johannesburg in a big way.

The city, which just recently was in the international limelight as headquarters of the 2010 Football World Cup, straddles a major portion of the vast mesh of tunnels from which the precious metal got mined. But now the very foundations of what is known in the vernacular as iGoli, or place of gold, are at risk.

The foundations of many of these buildings are at risk of being corroded by acidic water flooding abandoned mine tunnels under the city.

The threat being sketched with increasing urgency by environmentalists is that of rain and ground-water seepage causing water levels to rise in the defunct mine shafts. The water is highly acidic from the chemical reaction that happens when the pyrite in broken rock is exposed to water and oxygen.

Operating mines are required to pump what is called acid mine drainage into reservoirs where it gets treated with lime stone to lower the acid levels for it to be systematically released into river systems where wetlands play a further vital part in clearing the water.

The trouble is that most of the region's mines have shut down and extraction and treatment of their water have stopped long ago. The result is that their acidic water has been rising at such an alarming rate that environmentalists fear it could soon reach and start corroding the foundations of the city's high-rise buildings and even start seeping into underground garages.

Mariette Liefferink, chief executive officer of the Federation for a Sustainable Environment, an association comprised of various environmental organizations, says the area known as the Witwatersrand Gold-Mining Basin has an estimated 6 billion tons of iron pyrite tailing. This is the waste left from more than a hundred years of mining that has produced about 43,000 tons of gold and 73,000 tons of uranium.

To the west of Johannesburg, in what is defined as the gold-mining region's Western Basin, acid mine drainage is already spilling into rivers, killing aquatic life and posing a threat to humans and animals. It is posing a danger as well to the Cradle of Humankind World Heritage Site that comprises a number of palaeontological sites, including the Sterkfontein Caves, made famous by the discovery of Mrs Ples and Little Foot, skulls of a species of early man who lived about 2 million years ago. The fear is that the acid water will start flooding the caves and destroy their dolomite rock.

The danger which polluted water holds for the natural environment has just been brought to prominent attention by the plight of two hippos kept in a lake in the Krugersdorp Nature Reserve on the western outskirts of the industrial complex.

Situated downstream from a mine, the hippo pool has become so drenched by the toxic sludge resulting from large amounts of lime that got dumped into the river to treat the acid water that there is now serious concerns about the safety of the animals. It is feared it might be affecting their skins and their sight.

The National Council of Societies for the Prevention of Cruelty to Animals (NSPCA) is keeping tabs on the animals. The manager of its wildlife unit, Brenda Santon, has been quoted by newspapers as saying: "Obviously, we are concerned about those hippos. This whole acid mine drainage situation has been going on for years and it is a serious situation that the authorities need to look at."

Liefferink has given the South African Parliament's Portfolio Committee on Water and Environmental Affairs a comprehensive briefing on the extent of the danger, at the end of which she says she received standing applause. Whether that implied a readiness to act, she's not sure.

Even the government's own Department of Water and Environmental Affairs joined in warning members of Parliament about the urgency of the problem. Its deputy director of water quality management, Marius Keet, has been reported as telling the committee that the acid water could have catastrophic consequences for the Johannesburg central business district if not stopped in time. He urged the urgent installation of a new pumping station and upgrades of the high-density sludge treatment works.

The money being asked for in order to take these interim measures is not much, but there is no sign yet of Parliament being ready to vote it. The funds the government has allocated for treatment purposes come to the equivalent of hardly a million dollars. This while experts are saying that it is in fact going to cost billions upon billions to contain the problem.

The inaction indeed seems to stem from a paralysis in the face of so daunting a problem.
Lieffferink says that analyses show that if the costs of remedying the ecological effects of gold mining got taken into account in the first place, then it is doubtful it would have been considered worthwhile carrying on with it.

The first report about its effects on the country's water quality was submitted nearly half a century ago. But that went unheeded, as happened to subsequent submissions.

Liefferink believes, however, the chances are good that politicians and business people will be stirred into action now that they are starting to realize that acid mine drainage is not only endangering the natural environment but the very foundations of their own enterprises as well.