Thousands of families live near Johannesburg in South Africa surrounded by huge spoil heaps. The mounds of leftover rock are the result of 140 years of gold mining. The wind whirls up dust every day, which blows into houses and gardens. This dust contains uranium, a toxic heavy metal, and researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have now investigated the extent to which children in these areas are contaminated.
The scientists analyzed more than 400 hair samples from children. The result is clear: children from mining regions have significantly more uranium in their hair than children from areas without mines. "The dumps are often located directly in densely populated residential areas. It is known that toxic substances are transported to the houses in dust particles by wind, soil and water, especially in the dry season," explains Dr. Susanne Sachs from the Institute of Resource Ecology at the HZDR.
Further investigations needed
The study shows: The closer children live to the spoil tips, the higher their uranium exposure. Gender and age also play a role. The Witwatersrand Basin around Johannesburg is home to the largest gold deposits in the world. The spoil heaps extend over 400 square kilometers. They contain not only uranium, but also lead and arsenic. People absorb the toxins through the air, water, soil and food, especially through vegetables and grain from contaminated areas.
The researchers cannot yet say whether the measured values lead to health problems. This would require further studies. However, Sachs emphasizes the importance of the results. "The study helps to raise awareness in communities without unnecessarily stirring up fears," says the scientist. However, the measurements clearly show that better protective measures are needed for local people. In addition to the HZDR, the VKTA, Wismut GmbH and several South African universities were also involved in the international project. The researchers see their work as an important step towards better protecting affected communities.
