keywords: Pollution load index, heavy metals, Dam, Shika, Nigeria
Eleven sampling sites along Shika Dam, Sabongari LGA, Kaduna State, Nigeria were chosen to collect and assess the levels of As, Cr, Ni, Pb, Co and Cd in the dam water using pollution load index (PLI). Results of the Metal analysis revealed that Cd and As present in the water were above the permissible limits of WHO and FAO, respectively. This clearly showed that the water is highly polluted with respect to these metals. However, the levels of Cr, Pb, and Ni detected in the samples were below the WHO permissible limits of 0.1, 0.05, and 0.05 mg/L, respectively. The Cr, Pb and Ni detected permissible limits across the Dam. The physico-chemical parameters that were analyzed include: DO, BOD, COD, Turbidity, TSS, Colour, EC, pH, NO –N, PO –P, and NH3–N. ANOVA showed that there was a significant difference in the concentrations of the Cd and Ni across the sampling points at 95% confidence limit (P ≤ 0.05) while Pb, Cr, and As showed no significant difference in the concentrations across the sampling points.Pollution Load Index (PLI) was used as a tool to investigate the level of pollution in the quality of water in the Dam. The PLI recorded revealed and confirmed that Shika Dam water is highly polluted with As and Cd metals as the level recorded were > 1, a clear indication that the water is highly polluted. The trend in the PLI levels were H (7.287) < F (7.310) < D (7.678) < I (8.430) < C (8.821) < K (9.531) < A (10.0770) < G (10.487)< B (12.540) < J (14.728). Also, results of the PLI’s indicates that point H is the least polluted while point J is the most polluted of all the sampling points analyzed which was attributed to anthropogenic activities like the use of pesticides and fertilizers containing Cd and As on the farmlands close to the study area.