Gold mine pollution hampering smallscale growers

Lesego Khomo, senior lecturer in the Department of Environmental Science at the University of South Africa, explains how gold mine pollution is poisoning Soweto’s water and soil.

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For 140 years, gold mines in Johannesburg have been leaking wastewater contaminated with heavy metals. The acid mine drainage from Johannesburg’s estimated 278 abandoned mines and 200 mine dumps includes uranium (a radioactive metal), toxic arsenic, copper, cobalt, nickel, lead and zinc. Acid mine drainage can pollute land and water sources up to 20km away from a mine unless it is remediated by mining companies. The contamination cascades through food webs and poisons river water, plants and animals.

Before 1994 in South Africa, African communities were forcibly relocated to places near mine dumps in Soweto, south-west of Johannesburg. Today, Soweto is home to 1,9 million people who are exposed to acid mine drainage.

Fellow environmental scientists Salerwe Mosebi, Khayalethu Ntushelo and I researched how acid mine drainage affects urban agriculture in Soweto. Residents of the area rely on their small vegetable gardens to supplement their income and help meet their nutritional needs.

Our research found that acid mine drainage has contaminated the streams, irrigation water sources and subsequently, the soil on the land adjacent to the Klip River, which flows south and west of Soweto.

EXPOSURE TO HEAVY METALS

In very mild doses, exposure to heavy metals in acid mine drainage can cause dehydration and abdominal pain. In cases of serious exposure, birth defects, brain damage, cancer and miscarriages can result.