Speciation Study of Heavy Metals in Water and Sediments from Asunle River of the Obafemi Awolowo University, Ile-Ife, Nigeria

摘要

A nine-step sequential extraction protocol of Zn, Mn, Cd, Cu, Ni, Co and Pb in sediments from Asunle River that receives effluents from the waste dumpsite of the Obafemi Awolowo University, Ile Ife Nigeria was carried out. Total and dissolved levels of the heavy metals in water samples were also determined using Flame Atomic Absorption Spectrophotometer (FAAS). The results of total metal concentration (μg/mL) in water ranged from 0.04 ± 0.01 Cd to 2.25 ± 0.57 Zn while the mean levels of dissolved metal in water ranged between 0.004 ± 0.000 μg/mL and 0.87 ± 0.17 μg/mL. Mean levels of total heavy metal (μg/g) in the sediment samples ranged between 10.99 ± 2.18 – 74.62 ± 11.96 in Pb and 645.10 ± 62.15 – 3753.03 ± 176.29 in Mn. The apparent mobility and potential bioavailability for each metal in the sediment was 70%. The study showed that both the water and sediment samples were contaminated with heavy metals to varying degrees primarily as a result of effluents discharging into the river from the dumpsite within the vicinity of the river.