A comparative study on the hydrography of the coast of Chennai

Surface seawater samples were collected from two different stations along the Coast of Chennai, Station-1, the Ennore Coast where the fly ash effluent from the Ennore Thermal Power Station (ETPS) is directly discharged into the water and Station 2, the Kovelong Coast which is free from such point sources of pollution. Samples were collected between 8.00 a.m. and 9.00 a.m. during low tide from the two sampling Stations for a period of two years i.e. from April 2005 to March 2007. Samples were analyzed for temperature, pH, salinity, different forms of alkalinity (total alkalinity, carbonate alkalinity and total CO 2 ) Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), ammonia nitrogen (NH 3 -N), nitrite nitrogen (NO 2 -N) and nitrate nitrogen (NO 3 -N), and phosphate phosphorous (PO 4 -P) and N: P ratios. All the parameters studied except salinity and DO were high at Station 1 when compared to Station 2. Further wide fluctuations in the various physico chemical parameters studied were also recorded in samples collected from Station 1.