SEASONAL VARIATION IN PHYSICOCHEMICAL PARAMETERS AND HEAVY METAL CONCENTRATION IN WATER ALONG RIVER YOBE IN GASHUA

The physicochemical properties and heavy metal concentrations of water from three sampling sites were analyzed using standard methods and Atomic Absorption Spectrophotometry (AAS). The pH values ranged from 7.10 to 7.77, falling within acceptable limits. Electrical conductivity was higher in the dry season (0.56±0.00, 0.59±0.003, 0.58±0.003 µS) than in the wet season (0.46±0.01, 0.48±0.01, 0.47±0.03 µS). Dissolved oxygen generally met WHO and USEPA standards, although temperature was elevated during the dry season, and dissolved oxygen peaked above guideline limits in the wet season. Analysis of variance (P < 0.05) indicated significant seasonal differences in measured parameters. AAS results showed spatial variation in heavy metal concentrations across the sites. Most metals were higher during the dry season, except arsenic (As), cadmium (Cd), and lead (Pb), which were consistently low in both seasons. Zinc (Zn), chromium (Cr), arsenic (As), iron (Fe), and nickel (Ni) levels exceeded USEPA safe limits for drinking water (0.01, 0.01, and 0.001 mg/L, respectively). Overall, some metals remained relatively high across all sites and seasons, indicating potential contamination risks.