Preliminary Study on Accumulation and Depuration of Copper, Zinc, and Lead in Tilapia (Oreochromis mossambicus) under Laboratory Conditions

Tilapia (Oreochromis mossambicus) was studied for the uptake and elimination of single metals namely Copper (Cu), Zinc (Zn) and Lead (Pb) under laboratory conditions. Tilapia was acclimatised at 25 ± 2° C for 4 days. The dissolved oxygen and pH of water samples were maintained at 6 - 7 mg/L and 7.6 ± 0.1 respectively. The exposures to Cu (0, 5, 10, 15 and 20 mg/l), Zn (0, 10, 15, 20 and 25 mg/L) and Pb (0, 1, 2, 3 and 4 mg/L) over a period of 4 days were followed by 4 days of depuration. The accumulation and depuration patterns of Cu and Zn were not apparent and statistical analysis (t-test) did not show any significant difference (p>0.05) for both phases. The results indicate that tilapia can be used as a biomonitor for Pb as there was significant difference (p<0.05) between accumulation and depuration of Pb, particularly for higher exposures (3 mg/L and 4 mg/L Pb).