Rivers serve as vital interfaces between human activities and natural ecosystems, yet their water quality is increasingly threatened by urban growth, industrial discharge, and agricultural practices. Smaller river systems in Indonesia such as those in Palopo City remain understudied compared to the country’s major basins, leaving important knowledge gaps regarding localized pollution pressures. This study evaluates the physicochemical characteristics and pollution status of Palopo’s rivers across dry and rainy seasons. Water samples collected from five representative sites (residential, agricultural, industrial, urban, and mixed-use) were analyzed for pH, DO, BOD, COD, turbidity, nutrients (NO₃⁻, PO₄3⁻, NH₃), and heavy metals (Pb, Cd, Hg, As).Substantial spatial and seasonal variation was observed. Mean BOD (3.5–4.8 mg/L) and COD (18–25 mg/L) frequently exceeded WHO guideline values, particularly at industrial and urban locations. Heavy metals such as Pb (0.05 mg/L) and Cd (0.007 mg/L) also surpassed permissible limits, with concentrations intensifying during the rainy season due to runoff and sediment resuspension. Water Quality Index (WQI) classifications indicated “good” conditions upstream (WQI = 45), “moderately polluted” conditions in residential and agricultural zones (WQI = 60–68), and “heavily polluted” conditions at industrial and urban sites (WQI = 78–85). Overall pollution loads were approximately 30% higher in the rainy season. These findings highlight strong links between anthropogenic activities and water quality degradation in Palopo’s smaller river systems, underscoring the need for improved wastewater treatment, stricter industrial effluent regulation, and sustainable agricultural management.
Fachrudin et al. (Thu,) studied this question.