Bioaccumulation Profile of Selected Heavy Metals in Whole Tissue of Macrobrachium macrobrachion and Macrobrachium vollenhovenii from Benin River in Delta State, Nigeria

Bioaccumulation of selected heavy metals in whole tissue of shrimps (Macrobrachium macrobrachion and Macrobrachium vollenhovenii) inhabiting a stretch of Benin River in Delta State, Nigeria was studied. Water samples for heavy metal determination were also collected from three different locations within the sampled stretch from January to June, 2013. Heavy metal concentrations were quantified with Unicam Atomic Absorption Spectrometry (PG 550). The concentrations of heavy metals in the surface water samples (mg/l) were Fe(0.40),Zn(0.17), Mn(0.03), Cu(0.04), Cd (0.01), V (0.02), Cr (0.02), Pb (0.02) and Ni (0.06).The mean heavy metals concentrations in whole tissue of M. macrobrachion in mg/kg were: Fe (73.04), Zn (13.47), Mn (8.28), Cu (3.43), Cd (1.12), V (1.79), Cr (2.60),Pb(1.30), Ni (6.17) while in M. vollenhovenii the concentrations of these heavy metals in mg/kg were: Fe (8.01), Zn (5.55), Mn (2.74), Cu (1.42), Cd (0.46), V (0.73), Cr (1.27),Pb(0.54), Ni (2.54). The concentrations of these heavy metals in both shrimps (except Cu in M. vollenhovenii) exceeded the acceptable standards of WHO and USEPA. Bioaccumulation factor (BAF) for the heavy metals which in all cases were > 1, is an indication that these heavy metals were bioaccumulated and further evidence that M. macrobrachion and M. vollenhovenii can be used as bioindicators of heavy metal pollution.