Water Quality Alterations of a Tropical Suburban Lentic Ecosystem Due to Sewage Influx

Abstract

Lentic freshwater bodies serve mankind in different ways of which prime importance bags as sources of drinking water for local population. However, unscrupulous activities of mankind destroy pristine water sources by discharge of sewage, effluents, plastic pollution, etc. An investigation was undertaken to assess heavy metal content and seasonal physico-chemical parameters in a suburban sewage dumping pond in comparison with a neighbouring non-sewage dumping pond. Seasonal water samples were analysed to quantify trace metals (Pb, Cd, Cr, Ni, and Zn) and physico-chemical parameters such as temperature, pH, dissolved oxygen, electrical conductivity (EC), total dissolved solids (TDS), biochemical oxygen demand (BOD) and chemical oxygen demand (COD) employing standard methods and procedures. Pre-monsoon registered significantly elevated concentrations of heavy metals in the sewage-fed pond. Physico-chemical parameters exhibited marked seasonal variability with EC, TDS and COD demonstrating positive correlations with heavy metal concentrations, suggesting enhanced metal solubility and mobility under altered hydro-chemical conditions. Pearson correlation and principal component analysis (PCA), revealed strong interrelationships between anthropogenic inputs, redox potential, and seasonal fluctuations. The study underscores the synergistic effect of sewage influx and seasonal variation on metal speciation and aquatic chemistry, advocating the urgent need for integrated pond ecosystem management.