Effect of thermal power plant effluent on the physico-chemical parameters of Thoothukudi coastal waters, South India

Abstract

The coolant water discharge area of a thermal power plant in Thoothukudi, Tamil Nadu was investigated to elucidate the changes in the coastal water and sediment quality characteristics. Water and sediment samples were collected from three different stations namely station I (about 900 m away from coolant water discharge point), station II (about 1250 m away from discharge point) and station III (about 1600 m away from discharge point) and analysed for the various physico-chemical parameters. The dissolved oxygen level increased with increasing distance from the discharge point i.e., from station I to III, whereas the temperature values showed decreasing trend. Concentration of ammonia, nitrite, nitrate and phosphate were found in the decreasing order from station I, II and III. Accumulation of heavy metals was in the order of Al > Fe > Cu > Zn in the water samples and found slightly higher than the standards prescribed by European countries. The exchangeable phosphorus fraction appeared as the first major contributor among the different fractions of total sedimentary phosphorus. This study clearly explains that the effluent discharge in adjoining coastal waters affects the water and sediment quality.