An analysis of some heavy metals in the water, sediments and some fishery organisms from Yewa Lagoon, Nigeria

Abstract

The concentration of heavy metals(Zn, Ni, Pb, Cd and Cu) in the muscle of three fishery organisms (Chrysicththys nigrodigitatus, Sarotherodon galilaeus and Peneaus monodon)and in environmental samples of waterand sediment were tested in Yewa Lagoon, Nigeria. Five fishing villages along the lagoon were selected as the sample sites where these metals were tested. The heavy metal content in the muscle of the fishery organisms was Zn > Ni >Pb> Cu > Cd;Zn > Ni >Pb> Cd > Cu and Zn > Ni >Pb> Cd > Cu in C.nigrodigitatus, S. galilaeus and P. monodon respectively. The heavy metal concentrations in the sediment was Zn >Pb> Cu > Ni > Cd. However, nickel and cadmium were not present in the water at two sampling sitesof Yewa Lagoon.The water of Yewa Lagoon is polluted with all the five heavy metals which were all higher than the WHO standard. The concentration of Zinc in the fisheryorganisms were below the WHO standard. However, the high concentration of zinc in the water (which is well above the WHO standard) could be associated with the fact that zinc is naturally abundant in Nigeria soils.Keywords: Heavy metals, sediments, fishery organisms, lagoon