A researcher from North West University has found that the internal organs of cattle kept in the area around the Wonderfontein Spruit have been contaminated with uranium and cobalt, Beeld reported on Tuesday.
David Hamman, in research conducted for his Masters thesis in environmental science, analysed the animals' kidneys and found that uranium levels were 4,350 times higher than those in a control group.
In his study, titled "A Holistic View on the Impact of Gold and Uranium Mining on the Wonderfontein Spruit", Hamman found that the cattle were eating grass that grew next to the river.
This proved that the heavy metals bio-accumulated in the grass, Hamman said.
He also found that high concentrations of lead were found in irrigated lands next to the Wonderfontein Spruit - up to 17.3 times higher than those next to the Mooi River.
Hamman did a risk analysis for beef eaters, and found that no danger existed for people eating less than 0.13kg per day of the contaminated meat.
The Wonderfontein Spruit flows near Randfontein, through an area of about 90km containing the richest gold deposits in the world.