SCIENTISTS are running a second set of tests this week to examine the air quality in Mpumalanga’s eMalahleni area after initial testing revealed some of the world’s highest levels of a list of metals and chemicals that have been measured in a relatively new way.

The eMalahleni area was, in 2007, declared South Africa’s second National Air Quality Priority Area due to concern over air pollution from the region’s coal mining, metal smelting and coal-fired power plants.

Council for Geoscience researcher Henk Coetzee said on Monday the testing had "raised a flag" indicating a problem, but it was not yet known whether the chemicals and metals were affecting humans.

"Common sense says the hazard has been identified. Whether it translates to real risk, we don’t know," he said.

The database from which to interpret the test results was small because the test technique was relatively new, as was its use in this context, he said.

"It’s the first one in South Africa that we know of," he said.

An academic paper written from the first set of tests concluded that the "maximum levels for (chromium, nickel, vanadium, iron, and cobalt) were much higher than the maximum values recorded in other polluted areas around the world".

The Department of Environmental Affairs said it acknowledged air pollution was "of concern" in eMalahleni, but that it could not comment on the study as the department’s officials did not measure heavy metals such as chromium and barium, and did not have national ambient air quality standards for them.

According to the academic paper, published last August in the journal Environmental Science and Pollution Research, there were three main sources of the pollution — traffic, the smelting industry, and fly ash associated with coal-fired power plants and fly ash dumps.

The eMalahleni area is the world’s third-largest coal exporting region and heavy industry and coal-fired power stations had sprung up close to the power stations, according to the report.

"The result is that an ecologically sensitive area is heavily polluted by metal smelters, ironworks, coal mines, power plants and urbanisation. The mining and smelting industries, however, provide much-needed job opportunities, contributing to poverty alleviation," the report noted.

Dr Coetzee said the test results would now be presented to the Department of Environmental Affairs and the Medical Research Council.

"Now that we have these results, we want to know, ‘does it (the chemicals and heavy metal particles) get to people (and harm human health)?’"