Biochemical Effect of Some Chemical Pollutants On The Activity Of Some Enzymes In Tissues Of Fresh Water Fish

Pollution of the aquatic environment with heavy metals has became a moreserious concern during the recent years. The continual loading of metals into our environment creates water pollution problems due to their direct toxic effect on fish and other a aquatic organisms .This study was designed to examine the effect of certainspecies. The study consisted of two parts :- The. first part of the study was conducted in order to determine theoccurrence and distribution of the most commonly found heavy metals in waterand its accumulation in the different fish species and its organs from different aquaculture regions in Egypt. And the second part was directed to investigate ffect of exposing Nile tilapia Oreochromis niloticus and catfish Cl arias ariepinus to sublethaleaccumulation of copper and zinc and its effects on enzyme activities.The results obtained could be summarized as follows:(1): comparative study:-1· Physicochemical properties of water from four different aquacultureglons showed a significant differences between the four regions in Dissolvedygen, salinity, alkalinity and hardness and non significantly differences in pHues between the four different regions (Table 3 and Fig. 1) .2- Heavy metals in water ( copper, zinc, lead and cadmium) were’~nificantly higher in El-Husseniya farm followed by El-Marrzala lake and theIwest values showed in El-Abbassa farm and El-Fayoum farms. Wereas ironlbited a non significant differences between the four studied places (Table 4