Metal contamination of sediments and fish from the Vaal River, South Africa

Mining and other economic activities have led to the pollution of the Vaal River with metals of mainly industrial origin, but the consequences of this for animal and human health are unknown. Based on chemical analysis and histological examination, we report the contamination with 15 metals of river sediments and organs of sharptooth catfish Clarias gariepinus from four widely separated sites along this important South African waterway, sampled in spring 2010. Although some metals proved to be highly enriched, the fish organs showed no histological alterations that could be related to metal exposure. However, when the levels of metals that accumulated in C. gariepinus were used in a theoretical scenario, these concentrations signalled a potential threat to human health.