SEMIDIURNAL VARIATION OF SOME PHYSICOCHEMICAL PARAMETERS IN THE MAHANADI ESTUARY, EAST-COAST OF INDIA

Some physico-chemical parameters Like water temperature, pH, suspended solid, salinity, dissolved oxygen, NO2-, NO3-, NH3 and PO43- were inv estigated at the Mahanadi estuary under varying tidal conditions durin g monsoon, postmonsoon and premonsoon. The pH and salinity increased d uring high tides while suspended solid during ebbs were high especiall y during monsoon season. Concentrations of DO, inorganic PO43-, NO2- a nd NO3- increased during ebb regime and a decreasing trend was observe d starting from monsoon to premonsoon which indicates high productivit y towards the confluence with Bay. Higher values of ammonia during pre monsoon, particularly during low tides may be attributed to the discha rge of untreated domestic sewage and industrial effluents to the estua ry.