Assessment of spatial and temporal variations in the water quality of the Loktak Lake – Largest Ramsar Site in North-east India

Abstract

The present study was conducted in the Loktak lake which is the largest Ramsar site in the north-east India. In recent years, the lake has experienced a decline in its condition due to the accelerated process of urbanization, encroachment, high sedimentation, extensive use of chemical products and other anthropogenic activities. To assess the temporal water quality status, 38 sampling points were selected across the lake over four different seasons within a year. Twelve (12) physicochemical parameters like total alkalinity, calcium, chloride (Cl−), electrical conductivity (EC), dissolved oxygen (DO), total hardness, pH, phosphate (PO43−), salinity, sulphate (SO42−), total dissolved solids (TDS) and turbidity were analyzed using standard methods and instruments. The measured values of DO, EC, pH and turbidity were found beyond the desirable limits of BIS (Bureau of Indian Standards) and WHO (World Health Organization). This observation can be attributed to elevated levels of pollutants and microbiological processes. Lake water was ranged from slightly acidic to alkaline. High mean concentrations of EC (211.98) was found throughout the year. The study's findings indicate that the lake water exhibits a certain degree of pollution, necessitating appropriate treatment measures to ensure its suitability for both for domestic use and the preservation of wildlife. It is imperative to promptly develop effective management and conservation measures in order to mitigate the ongoing deterioration of water quality inside the lake and its associated ecosystem.