Spatiotemporal dynamics and seasonal influence on the microbial and physicochemical integrity of groundwater sources in rural cross river state, Nigeria

The availability of quality water resources is a significant challenge in many part of the world, including Nigeria. This study investigated the spatiotemporal dynamics of groundwater quality in Obudu and Obanliku, Cross River State. Bacteriological and physicochemical characteristics of 120 samples from wells and boreholes were analyzed across wet and dry seasons (January–June, 2025). Independent T-tests and the Weighted Arithmetic Water Quality Index (WQI) were used to determine significant differences and the overall physicochemical status. Physicochemical results generally aligned with WHO and SON standards, though significant seasonal variations occurred. While pH remained stable (p > 0.05), turbidity was significantly higher during the wet season in wells (3.15±1.81 NTU) and boreholes (1.56±0.40 NTU). E. coli peaked in wells during the wet season (4.76±4.11 cfu/100ml) and was lowest in boreholes during the dry season (0.31±0.36 cfu/100ml). Despite the WQI classifying water status as "Good" (27.30–37.10), all samples exceeded thresholds for total coliform, faecal coliform, and E. coli across both seasons. The study concludes that while the physicochemical status appears safe, pervasive bacteriological contamination renders these sources unsuitable for drinking. Household-level water treatment, regular disinfection of existing wells and environmental sanitation are urgently recommended to mitigate public health risks.