US EPA

5439675 

Journal Article 

Bioaccumulation of copper and zinc in Oreochromis mossambicus and Clarias gariepinus, from the Olifants River, Mpumalanga, South Africa 

Kotze, P; du Preez, HH; van Vuren, JHJ 

1999 

1 

Water SA
ISSN: 1816-7950 

25 

1 

99-110 

WOS:000078489500014 

The upper and lower catchments of the Olifants River are characterised by many anthropogenic activities that adversely impact on the water quality of the fiver. The present study indicated that both Cu and Zn are present in elevated levels as reflected in the bioaccumulation of these metals in the fish. Bioaccumulation differences in the different age and gender groups were generally not significant (P>0.05). This was due to the sampling of mostly adult fish and the exclusion of reproductive organs (gonads). Copper content in the organs and tissues indicated the following pattern: liver>gills>skin>muscle, but no specific pattern for Zn content was observed. The extent of accumulation differed in many cases between the two species, possibly due to differences in behaviour and feeding. Temporal variation in bioaccumulation occurred and generally indicated increased levels of bioaccumulation during periods of high flows. This phenomenon was ascribed to the influence of sediment-bound metals, being brought into contact with the fish at a higher intensity during these periods. Both Loskop Dam and Mamba Weir, the latter to a greater extent, are at present being exposed to levels of Cu and Zn which cause bioaccumulation. A more holistic biomonitoring approach is proposed for these impacted areas in an attempt to guide managers in a direction of improvement.