The present study displayed the histopathological alterations produced In kidneys of Sarotherodon galilaeus fish following exposure to gradually ascending sublethal concentrations of VA.VI, LC50 and double LC50 for 5 days each.
Kidneys from fish exposed to the low levels of mel ats showed slight changes in the proximal convoluted tubular epithelium which were slightly vaculated and the nuclei of its cells were karyorhectic. Hypertrophy, cloudy swelling and hydropic degeneration of some renal tubules as well as congestion of kidney blood vessels were common among fishes exposed to the medium levels of mat els (V4 LCso)- Atrophied cellular components of the Bowman's capsules and enlarged Bowman's spaces were also observed in such treated fishes.In the fish groups exposed to the highest concentrations of zinc and lead, degenerations in the cytoplasm of tubular epithelial cells were so drastic to the extent that the tubules as a whole appeared as if they were ghosts of tubules.The haemopoietic tissue was reduced in volume in fishes exposed to the LC50 of copper. It was crowded with necrotic cells in case of fishes exposed to theLCsoof lead. The above histological alterations are sufficient to cause nephrotoxicity that may lead to impairment in the excretory function of the kidney.