Assessment of threats to a Ramsar site from seafood processing operation effluents

Abstract

AbstractWaterbodies receiving effluents from seafood processing plants might experience severe eutrophication. The present study was carried out to assess the impacts of effluent discharges on water quality and phytoplankton populations in the Vembanad‐kol Wetland, located adjacent to seafood processing industries. It was conducted in the Cherthala–Aroor–Edakochi coastal belt of Vembanad Wetland, India, a region containing many processing plants. The trophic status of the lake was assessed with the Carlton trophic state index. Hypereutrophic conditions were observed more in the interconnected channels than in the main waterbody. There was a dominance of Bacillariophyceae, followed by Chlorophyceae, Cyanophyceae and Dinophyceae. Bacillariophyceae, Chlorophyceae and Cyanophyceae were comparatively higher in the interconnected channels, whereas Dinophyceae was high in the main body of the lake. There is a shift in dominance from Chlorophyceae to Cyanophyceae in the interconnected channels, especially in the southern and central portion of the lake. There was a dominance of Cyanophyceae over Chlorophyceae, especially in the interconnected channels, being a characteristic of polluted water. Nitzschia sp and Navicula sp were abundant in the class Bacillariophyceae. The dominant species in the class Dinophyceae was Ceratium sp, which is known to proliferate in nutrient‐rich waters. The dominant members of the class Chlorophyceae were Ankistrodesmus sp and Scenedesmus sp. Furthermore, Oscillatoria and Phormidium were higher in number in the class Cyanophyceae, indicating the presence of pollutants of biological origin. Waste discharges from the seafood processing industry are a major factor contributing to an alarming rate of organic pollution and subsequent eutrophication in the lake. The results of the present study highlight that further expansion of the seafood industry in the Cherthala–Aroor–Edakochi coastal belt of Vembanad Lake is not desirable.