Sabo A^1,, Gani A. M², Ibrahim A. Q¹

There has been a lot of concern on the rate at which industrial and domestic wastes are discharged into River Delimi in north central Nigeria. This study was an attempt to assess the status of heavy metal pollutants (Cd, Cu, Pb and Zn) in sediment and water from River Delimi in Jos city, with a view to determining its ability to support aquatic life and suitability for use in vegetable crop irrigation. The study was conducted at three major irrigation sites at Gangare (station I), Farin Gada (station II) and main campus of University of Jos (station III) along River Delimi and one control site at Lamingo Dam (station IV) all within Jos city. The total metal contents in water and sediment were determined using Atomic Absorption Spectrophotometer (AAS) after extraction with Conc. HNO₃ and aqua-regia respectively. Results of the study revealed that the total metals content in water and sediment were generally higher at the study compared to the control site. At the study site, the mean Cd concentrations in water at stations I (0.14mg/L), II (0.381mg/L) and III (0.300mg/L), Cu at stations I (0.341mg/L) and II (0.371mg/L) were above the limits of 0.01mg/L and 0.20mg/L for Cd and Cu respectively for irrigation water recommended by FAO. Further analysis on the sediment pollution status using Contamination Factor (CF) revealed that Cd obtained from all the sampling sites showed considerable (3 ≤ CF ≤ 6) contamination while the other metals showed low (CF < 1) contamination. The use of Geoaccumulation Index (I-geo) also showed that only Zn at station IV (control site) attained unpolluted status (Class 0) It is recommended among others that measures should be put in place by relevant authorities to regulate the indiscriminate dumping of domestic waste and untreated industrial effluents into the river.

heavy metals, pollutants, river delimi, water, sediment