Seasonal Variability of Physicochemical Parameters in the Coastal Quaternary Aquifer System of Sergipe

Abstract

This study assessed the temporal and spatial variability of physicochemical parameters in the Quaternary Aquifer System (SAQ) at the Sergipe Hydrogeological Research Site (SEHRES), located on the campus of the Federal University of Sergipe, in São Cristóvão, Brazil. Two monitoring campaigns were conducted in 15 tubular wells during the dry (October 2023) and rainy (July 2024) seasons. The parameters measured included temperature, dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS), salinity, pH, and turbidity. An increase in DO levels was observed during the rainy season, while EC and TDS values decreased, suggesting dilution due to aquifer recharge. Salinity remained stable, and pH values were predominantly acidic with no significant seasonal variation. Turbidity showed anomalous values in one well during the dry season, indicating possible localized contamination. Spatial analysis revealed consistent patterns of EC, TDS, and pH along the hydraulic gradient, indicating interaction between groundwater and the local geology. Notably, variations observed in the well near the highway suggest potential anthropogenic influence. These findings highlight the importance of continuous groundwater quality monitoring to support sustainable resource management and to identify hydrochemical changes driven by seasonal dynamics and human activities.