الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
•Since the industrial revolution, the efforts of removing man-made pollutants from the natural environment have been unable to keep peace with the increasing amount of waste materials and a growing population that further aggravates the situation. This has often resulted in the transformation of lakes, rivers and coastal waters into sewage depots where the natural biologic balance is severely upset and in some cases totally disrupted 1.The main objective of the present study is to evaluate the levels of some heavy metals (Cu, Zn, Cd, Pb) in fish of family Mugilidae (Liza aurata, Liza ramada and Mugil cephalus), water and plankton from a different locations around lake Manzala: The locations were chosen so as to represent different habitats of different degrees of pollution. 2.What is the relationship between the presence or absence of the parasites and the polluted sites (i.e., may the parasites be used as indicator for pollution)? •The present study shows : Cu, Zn, Cd and Pb were concentrated more in plankton followed by fish. The lowest heavy metals concentrations were found in the water samples. Form this study it could be concluded that site V displayed the highest metal concentrations in tissues of family muglidae. The total values of Cu, Zn, Cd and Pb were detected in the following orders: Muscles> skin > gills and it could be noticed that Mugil cephalus contained relatively higher concentrations in its organs than the two other species of family mugilidae . the level of tested heavy metals increased at some sites and seasons, and exceeded the permissible limit in fish sometimes but mullet muscles in the present study are considered safe for human consumption. •The susceptibility of the parasites let us concluded that the possibility of using parasites as biological indicators for healthy environment. In this respect, it can suggest that, the absence or reduction of ectoparasites (Ligophorus spp and Solostamenides mugilis) can be used as bioindicator for the pollution in the fish environment. However, the presence or high intensity of endoparasite (Saccocoelium tensum) could use as a bioindicator for the pollution in the fish environment and verse by verse.