Effects of lead on Na+, K+-ATP ase activity and accumulation of lead in tissues of Oreochromis niloticus exposed to different concentrations of lead and lead-zinc mixture

In this study, effects of lead on Na+, K+-ATP ase enzyme activity and accumulation in kidney, liver, gill and muscle of Oreochromis niloticus were investigated in both Pb and Pb+Zn mixtures. The fish were exposed to 0.1 mg/L Pb, 0.1 mg/L Pb+0.5 mg/L Zn, 0.5 mg/L Pb, 0.5 mg/L Pb+2.5 mg/L Zn and 1.0 mg/L Pb, 1.0 mg/L Pb+5.0 mg/L Zn mixtures for 7, 14 and 21 days to observe lead accumulation and Na+, K+-ATP ase enzyme activitiess in tissues.Lead accumulation increased with increasing concentrations of lead in the medium and with increasing periods of exposure tissues studied. Highest accumulation occured in the kidney followed by gill, liver, and muscle.In all exposure period, accumulation of lead in whole tissues of O. niloticus decreased in the presence of zinc. In all mixed exposure concentrations, zinc significantly reduced the accumulation of lead in the kidney, gill, liver and muscle of O. niloticus.In tissues of O. niloticus, Na+,K+-ATP ase activities were altered by exposure Pb and Pb+Zn mixtures. In all the concentrations tested, lead caused a decrease in Na+,K+-ATP ase activity in the gill, kidney and muscle while it caused an increase in liver tissues. In Pb+Zn mixtures have been determined to decrease or to have no effect Na+,K+-ATP ase activity in all tissue of exposed fish.Keywords: Lead, Zinc, Accumulation, Na+,K+-ATP ase, Oreochromis niloticus