Role of Natural Flocculation in Eliminating Toxic Metals.

Metals as the most common environmental pollutants derive from different sources and have far-reaching harmful impacts on flora, fauna and human health. Moreover, metals cause irreversible damages to marine ecosystems. Estuaries are most productive ecosystems for living creatures and act as a transporting corridor for exchanging materials from river to water bodies including oceans, seas and lakes. One of the most important processes in this region is flocculation. Not only does flocculation process convert a huge percentage of metals from dissolved phase to particulate phase in providing micronutrients to aquatic organisms, more importantly, but it also eliminates metals from aquatic ecosystems and gives aid to the pollution of water bodies to be on the decrease. Moreover, the chemical mass balance between river and sea is substantially influenced by flocculation process. Salinity, pH, dissolved oxygen, dissolved organic carbon and sodium hypochlorite as important factors affect the flocculation of metals during estuarine mixing of river water with seawater. It is vital to make use of natural processes in eliminating pollutants. Thus, natural processes need to be recognized and promoted by various means.