Radioactive waste outside mining areas in the catchment of the Wonderfonteinspruit poses no risk to the public, according to experts.
However, they have strongly recommended that the areas be cleaned up, the Department of Water Affairs and Forestry said on Wednesday.
The stream runs 90km from the western outskirts of Johannesburg before flowing into the Mooi River near Potchefstroom.
The department said it and the National Nuclear Regulator (NNR) brought in experts to look at contamination resulting from processing of uranium-bearing gold ore.
”The ore in the gold-bearing reef is associated with low levels of radioactivity, and over many years of mining some of this material has been dispersed and accumulated in certain areas,” the department said.
The experts, who included local and international scientists, found that none of the contaminated sites outside the mining areas or accessible to the general public posed any health risk. They also recorded the known areas of concern.
”Now detailed assessments of the extent of the problem at each site will be undertaken so as to develop effective remediation plans,” the department said.
It said radioactivity had been identified as a concern in the mining sector in 1995, and Wonderfontein was identified as a priority area for remediation.
According to a study by German scientists compiled last year but never officially made public, meat, milk, maize and other foodstuffs produced near the stream are probably harmful to people.
The report said water used to irrigate crops had absorbed polonium and lead, the radioactive by-products of uranium and radium.
Harmony Gold, one of the mines responsible for the uranium discharge, has in the past relayed to farmers on its lands a directive from the NNR that livestock should not drink water from the stream.
However, Water Affairs and Forestry Minister Lindiwe Hendricks has told Parliament that the water is safe for drinking purposes as far as radioactivity levels are concerned. — Sapa