Seasonal Dynamics and Safety Assessment of Physicochemical and Heavy Metal Parameters in Jega River, Kebbi State, Nigeria

Jega River in Kebbi State, Nigeria, is an important freshwater resource that supports diverse ecosystem functions. Despite its significance, recent comprehensive assessments of its water quality are lacking. This study evaluated the safety and seasonal variation of physicochemical parameters and heavy metal concentrations over a one-year period. Water samples were collected monthly between September 2021 and August 2022 and analyzed following standard protocols. The results revealed statistically significant (p < 0.05) seasonal variations in most parameters. For instance, water temperature peaked in May (32.00 ± 0.58 °C) and was lowest in August (27.71 ± 0.33 °C), reflecting seasonal thermal fluctuations. DO levels were highest in July (7.47 ± 0.20 mg/L) and lowest in March (2.73 ± 0.00 mg/L), while BOD reached its maximum levels in March (43.60 ± 4.45 mg/L). Among the heavy metals, Cd exhibited the highest concentration in May (0.627 ± 0.05 mg/L), Cu peaked in April (0.051 ± 0.00 mg/L), Mn was highest in November (0.73 ± 0.20 mg/L), and Zn reached its maximum concentrations in November (0.14 ± 0.00 mg/L). Notably, concentrations of Cd, Mn, Ni, and Pb, as well as DO and BOD, exceeded the World Health Organization (WHO) permissible limits for surface water. This indicates potential risks to both aquatic organisms and human health. Correlation analysis showed strong positive and negative relationships among several parameters, suggesting common pollution sources and complex interactions. Overall, these findings provide valuable data for water quality monitoring, pollution control strategies, and sustainable water resource management in line with national policies.