ABSTRACT
The continuous increase in heavy metal contamination of estuarine and coastal marine waters is directly attributable to industrialization and development in the coastal zone. The contamination by most heavy metals in coastal environments reflects localized impacts from point or multipoint discharges from municipal and industrial sources. Heavy metal toxicity in aquatic organisms is of immense interest to toxicologists. At elevated levels, heavy metals act as enzyme inhibitors in organisms. Water quality standards, in turn, have been developed on the basis of toxicity data, and extensive tables of heavy metals for freshwater fish, invertebrates, and marine organisms are available. The fate of heavy metals in regard to physicochemical processes is contingent upon conditions in the individual estuarine system. The exchange of trace metals between dissolved and particulate phases appears to be a regular phenomenon in estuarine systems. In the ocean basins, only approximate estimates have been proffered for the atmospheric input of most of the trace elements.
