Physico-chemical characteristics of the coastal water off Devi estuary, Orissa and evaluation of its seasonal changes using chemometric techniques

Abstract

Devi estuary is one of the major tributaries of the Mahanadi riverine system in Orissa. Modernization and industrialization in its neighbourhood in the north in the recent past have greatly influenced many tributaries of the Mahanadi and the adjacent coastal environments. To trace the influence of this modernization activity further down south off Devi estuary and to understand the quality of the Devi estuarine water reaching the coastal region, investigations on physicochemical parameters (temperature, pH, salinity, dissolved oxygen), including dissolved nutrients (PO sub(4)-P, NO sub(3)-N, NO sub(2)-N, SiO sub(4)-Si) were carried out in the water off the mouth of the Devi estuary, during different months of the summer and winter seasons in 2006-07. The multivariate statistics and principal component analysis applied to the datasets, indicated three factors each during the summer and winter seasons influencing the water to the extent of 77 and 80% respectively. Principal axis factoring and alpha factoring have been used to observe the mode of association of parameters and their interrelationships, for evaluating water quality during the summer and winter seasons. The results indicated the addition of phosphates and silicates to the coastal water by the Devi estuary from natural sources during both the seasons. The anthropogenic nitrogenous species, as a fallout from modernization activities in the north, are more clearly observed off the mouth of the Devi estuary during the winter season. The study indicated that the Devi estuary adds sufficiently well-oxygenated, nutrient-rich water to the coastal region.