ASSESSING SPATIOTEMPORAL VARIABILITY OF MICRONUTRIENTS UNDER CHANGING HYDROCLIMATIC CONDITIONS IN THE TAMIRAPARANI RIVER BASIN, SOUTHERN TAMIL NADU

Abstract

The Tamiraparani river is the only perennial river in Tamil Nadu and serves as the vital lifeline for the southern districts of Tirunelveli, Thoothukudi, and parts of Virudhunagar, ensuring water security in a largely arid region. Originating in the Pothigai hills, it sustains agricultural, domestic and industrial needs, along with rich biodiversity. The present study investigates the temporal and geographical variability of micronutrient concentrations in surface and groundwater of Tamiraparani River watershed. Fourteen sites were chosen for collection of groundwater samples (n = 84) between November 2020 and February 2021, while sixteen locations were chosen for collection of river water samples (n = 96) between November 2021 and February 2022. The micronutrient level and adherence to drinking water standards were evaluated by analysing each sample. The findings show that micronutrient concentrations at every sampling location stayed within the World Health Organization in its acceptable bounds. In all research periods, temporal oscillations were more noticeable than geographical differences, according to variability analysis. In contrast to 2021, a relatively less degree of volatility was noted in 2022. Increased rainfall in 2022 is thought to have improved dilution and homogeneity of micronutrient concentrations throughout the basin, which is because there was less fluctuation. Furthermore, uniform micronutrient levels were found in the upstream, middle and downstream sectors, suggesting that localized pollution impacts were negligible. Overall, the results indicate that seasonal hydrological processes, rather than geographical variability are the key factors influencing the water quality in the basin, typically stays within reasonable limits. This study emphasizes the function of rainfall in controlling water quality in riverine systems and offers baseline insights on micronutrient dynamics.