الفهرس 
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Abstract
Pollution of a certain environment, means the presence of some new factor or factors which causes some changes in its overall picture. Various types of pollution in marine environment are known. Thus, we speak of chemical pollution, mechanical pollution and thermal pollution. Pollution by heavy metals is classified under the title of chemical pollution. Many investigators are concerned with studying their presence in the marine environment as well as their effect on marine ecosystem. The term heavy metals usually means, at least in the biological context, iron and metals denser than it.