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The current study aimed at establishing the levels and effects of heavy metals on immunity of fish in the Kafue River basin. The heavy metals analysed in fish muscle and soil included Copper, Zinc, Cobalt, Nickel, Chromium, Lead, Iron, Cadmium and Manganese using Atomic Emission Spectrophotometer. The study found the concentrations of heavy metals to be lower than set standards by FAO and WHO with Copper being the only metal showing significant differences between the sexes (p=0.009). There was a significantly lower level of Copper in fish muscle of fish (> 150g) that was collected upstream of the Copperbelt mining area. The study shows that Copper accumulation is dependent on size, weight, sex and species of fish. Heavy metal concentrations in soil were comparable between sites. However, Copper and Iron indicated higher concentrations (65.1±0.283 and 283.70±1.74 respectively) than WHO/FAO thresholds for agricultural soils. Multiple regression for lysozyme in kidney against sex and Copper was statistically significantly predicted lysozyme levels, F (2, 51) = 3.54, p< .0365, R2 = 0.12. p<0.05. The results show a significant interaction between lysozyme activity, sex of fish and Copper. A significantly higher (P<0.0028) condition factor was observed downstream the mining area indicating wellbeing of fish with the Chipata site (within the Copperbelt mining area) having the least coefficient of condition which could be attributed to metal contamination at the site. The haemoglobin concentrations were also reduced showing signs of anaemia and an increase in WBC was also indicated. A significant decline in RBC count was also detected at Mitunda site which may be attributed to various environmental effects but further studies would be needed to link this with heavy metal toxicity. |
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