Assimilative capacity of Cochin inshore waters with reference to contaminants received from the backwaters and the upstream areas

Abstract

Assimilative capacity of inshore waters off Cochin was assessed using data on hydrography, photosynthetic pigments, primary productivity, dissolved nutrients and trace metals collected over a period of three years (April 2003 - October 2006) from selected stations spreading over the source to the sink. Assimilative indices for Cochin estuary and inshore waters off Cochin were worked out and a scale of safe, desirable, caution or critical was attributed with regard to different parameters based on the score. The results revealed that in the estuary, total suspnded solids (TSS) and cadmium have reached critical levels and lead have attained levels of cautiion. Similarly, in the Cochin inshore waters, cadmium have reached critical levels while copper and lead have attained levels of caution.