Abstract:

Heavy metal pollution of seawater, sediment and shrimps of Qua Iboe River, Ibeno, Akwa Ibom State, Nigeria was studied for six months in dry and wet seasons. Seawater, sediment and shrimp samples were collected from five different points from the upper to the lowest course of Qua Iboe River flowing along Mkpanak Community. Heavy metals (Pb, Cu, Cd, Cr and Ni) concentration in seawater, sediment and shrimps from the studied river were determined using Atomic Absorption Spectrophotometric (AAS). The mean concentrations of heavy metals in seawater were 0.628, 0.072, 0.381, 0.486 and 0.631mg/l for Pb, Cu, Cd, Cr and Ni respectively for dry season and 0.427, 0.049, 0.214, 0.289 and 0.408mg/l for Pb, Cu, Cd, Cr and Ni in wet seasons. The corresponding values in the sediments were 3.552, 1.327, 2.578, 2.829 and 4.926mg/g for Pb, Cu, Cd, Cr and Ni respectively for dry season and 2.121, 0.943, 1.517, 1.777 and 3.675mg/g for Pb, Cu, Cd, Cr and Ni respectively in wet season. Also, the mean values of heavy metals in shrimps were 0.008, 0.308, 0.004, 0.039, 0.025mg/g for Pb, Cu, Cd, Cr and Ni respectively for dry season and 0.005, 0.196, 0.002, 0.020 and 0.017mg/g for Pb, Cu, Cd, Cr and Ni respectively in wet season. The results of heavy metals in seawater, sediment and shrimps were compared with International Standards. It was observed that all the heavy metals studied in both seasons were above the safe limit with exception of Ni in shrimp which was within the safe limit. Hence, this study recommended the need for appropriate regulatory legislation on the control, treatment and discharged of oilfield effluents into Qua Iboe River.