Assimilative and healing capacity of coastal waters against the Sewage and effluents released along the coast of Visakhapatnam industrial belt

Owing to increased anthropological activities, the coastal zone is receiving a vast quantity of sewage waste and industrial effluents. But conflicting views on the impact of these wastes on coastal waters prompted us to take up this study. Four sampling points along the coast were identified and analyzed the collected water samples for nutrients and chlorophyll-a during pre-and post-monsoon seasons. The results indicated that the study area was of mesotrophic type and the coastal water was well oxygenated with mean DO of 5.2mg/lit and was biologically productive at primary level with ambient levels of nutrients excepting slight higher concentrations of nitrate-nitrogen, phosphate-phosphorous and total nitrogen as 17.5 μgm/lit 19.0 μgm/lit and 502.8 μgm/lit respectively. Further, toxicological studies (bio-assay tests) of discharged effluents and coastal water samples were conducted on selective standard test organisms and compared with the control samples. They revealed that the impact of the discharges on the coastal environment was insignificant.