Abstract

PHOSPHATE CONTAMINATION AND TOXIC CYANOBACTERIAL BIOMASS IN THE EUTROPHICATED SURFACE WATER OF RIVER TAPI

Jay Bergi* and Pratibha Desai

Abstract

Background: Surat city in the western state of Gujarat in India completely relies on the supply of surface water from river Tapi. Tapi is heavily eutrophicated like many rivers of tropical region of the world. Presence of toxin producing cyanobacteria might be a concern for the public health using water supply from the river. Materials and Methods: Present study has analyzed presence and seasonal variation of phosphate as an indicator of nutrient contamination in river water. Diversity of cyanobacteria was studied by microscopy and chlorophylla was estimated spectrophotometric technique indicating cyanobacterial biomass. Results and Discussion: A seasonal increase in phosphate concentration (mg/dm3) was observed in Tapi water that resulted in the increase of chlorophyll-a concentration indicating increase in cyanobacterial biomass. Cyanobacterial genera were identified by microscopy, possibly producing hepatotoxins. Conclusion: A strong positive proportionate correlation exists between increase in nutrients such as phosphate contamination and harmful cyanobacterial bloom in Tapi. Presence of toxin producing cyanobacteria in surface water is an important issue that requires further investigation.

Keywords: Tapi River, Cyanobacteria, Phosphate, Chlorophyll-a, Hepatotoxins.