ASSESSMENT OF HEAVY METAL CONCENTRATIONS IN CRAB Sesarma angolense FROM BENIN RIVER, SOUTHERN NIGERIA

Abstract

Heavy metals concentrations were determined in the crab (Sesarma angolense) and sediment of Benin River, Niger Delta Region, Southern Nigeria using Atomic Absorption Spectrometer. Except for Cd and Ni, other heavy metal concentrations differed insignificantly (p>0.05) among the stations. Thus Cd and Ni are the principal elements responsible for spatial variability in terms of heavy metal concentration in the sediment. Mean values of the heavy metals Fe, Zn, Mn, Cu, Cd, V, Cr, Pb and Ni in sediment from the three stations were 2.23, 0.39, 0.07, 0.08, 0.02, 0.04, 0.03, 0.06 and 0.12 respectively. Fe, Zn, Mn, Cu, Cd, V, Cr, Pb and Ni were observed to exhibit average values of 37.33, 8.85, 7.57, 2.29, 0.74, 1.92, 3.84, 0.86 and 4.05 mg/kg respectively in whole tissues of Sesarma angolense sampled which indicated that the metals were bioaccumulated. The concentration of Cd and Pb in the crab were relatively higher than FAO/WHO permissible limit for items made to be consumed by man, thus this rendered population of S. angolense from Benin River unsafe for consumption. This calls for constant monitoring of the Niger Delta ecosystem in order to minimize adverse health impacts heavy metals.