Lake Burullus represents an economically important lake in Egypt , due to its rich fishery resources. Unfortunately, the lake is exposed to many kinds of chemical and biological pollutants in addition to the remains of agricultural and wastes that are disposed into it. So, the aim of the present study was compare the quality of water samples collected from three different sites along lake Burullus; a site of the lake in contact with the Mediterranean sea called El-Boughaz inlet, western sector of the lake where agricultural drainage discharged and eastern sector where agricultural and industrial effluents.Water quality of samples collected from the different studied sites along the lake showed highly significant (P< 0.01) differences with the highest values in the dissolved oxygen content and salinity at El-Boughaz inlet. However, water samples collected from the eastern and western sectors of the lake showed highly significant (P< 0.01) increase in ammonia, nitrite, Cu, Zn and Mn but insignificant (P> 0.05) Pb concentration. Bioaccumulation of either of the
studied heavy metals in gills, liver, kidneys and muscles of the Nile tilapia; Oreochromis niloticus collected from the eastern and western sectors of the lake was much higher than that of fish collected from El-Boughaz inlet. Moreover,
histopathological sections showed clear damage of gills, liver and kidney of fish collected from eastern and western sectors of the lake. Furthermore, Oreochromis niloticus collected from eastern and western sectors of the lake had lower condition factor values, hepatosomatic index,RBCs, Hb, Ht, serum total protein and total lipids but higher liver water
contents, WBCs, MCV, MCH, serum glucose, AST, ALT, creatinine and uric acid.The obtained results also revealed that the meat quality of the collected fish from El-Boughaz inlet was more superior than those of fish collected from the eastern and western sectors of the lake.