CONCENTRATIONS OF ZINC IN BARBUS-MAREQUENSIS FROM THE LOWER OLIFANTS RIVER, MPUMALANGA, SOUTH-AFRICA

Zinc was detected in all the tissues examined, but in variable concent rations. The highest zinc concentrations were detected in the skin and ovaries. These zinc concentrations also differed significantly from t he concentrations in the other tissues. The bioaccumulation pattern of zinc in the fish was determined as: aries>liver>gills>vertebrae>teste s>hindgut>foregut contents>kidney=foregut>hindgut contents>muscle>bloo d>fat>bile. Although significant differences (P<0.05) between localiti es were detected no clear trend as to where the highest bioaccumulatio n had occurred, could be established. Significant seasonal differences were detected, but it was not always the same tissue that indicates t hese seasonal differences. The zinc concentrations detected in the fis h suggest no serious zinc pollution in the lower Olifants River. Zinc levels detected in some of the tissues might indicate chronic exposure , causing possible sub-lethal effects. However, this should be investi gated before final conclusions can be made.