Coal has been used extensively in power generation where better technology is employed to ensure that there is a balance between ecology and economics. On the other hand there are also some significant disadvantages of coal fired power plants including the generation of millions of tons of waste and emission of harmful substances. In Tuticorin, the sea water is polluted in many reasons including the ash slurry is discharged into sea water. Sea water samples were collected from three different stations in Tuticorin coastal to study the physico-chemical characteristics. The analysis of different parameters such as temperature, pH, salinity, TDS, nitrite, nitrate, silicate, inorganic phosphate and total phosphate were carried out using standard methods. The studies reveal that the physico-chemical composition of all water samples were collected mainly depends on seasonal variations and discharge of solid waste fly ash from thermal power plant.