Concentrations of Heavy Metals in Selected Macro-Invertebrates of Dadin Kowa Dam, Gombe State, Nigeria

Abstract

Macro-invertebrates may serve as vectors of fish and human exposure to heavy metals and little or no information exist on the heavy metals concentrations in macro-invertebrates of Dadin kowa Dam. Therefore, the need to determine the heavy metals concentration in the most available macro-invertebrates (Anax junius, Pontala flavescences, Lanistes libycus, Nepa cinerea, Dyticus dauricus) of the Dam. All samples were analyzed using atomic absorption spectrophotometer (Bulk scientific, model 205). The result indicates that the concentration pattern of heavy metals in all the macro-invertebrates were in the order of Mg>Mn>Co>Cr>Ni>Cu>Cd>Pb. The bio-concentration factors were calculated in order to know the relationship between the concentrations of heavy metals in the macro-invertebrates and their surrounding environment (sediment). The pattern of bio-concentration factors in A. junius, P. flavescences, L. libycus, N. cinerea and D. dauricus were in the order of Co>Mn>Cu>Cr>Mg>Cd>Ni>Pb,Cu>Mn>Co>Cr>Mg>Cd>Ni>Pb,Co>Mg>Mn>Cu>Cr>Cd>Ni>Pb,Cu>Mn>Cr>Mg>Co>Ni>Cd>Pb and Mn>Cu>Cr>Mg>Cd>Pb>Co>Ni respectively. The result suggests that heavy metals uptake by the macro-invertebrates do not exclusively depend on the concentration levels by sediment exposure alone but may largely depends on their feed, feeding habits and biochemical needs of individual macro-invertebrates. The bio-concentration factors estimated here provide a useful tool for predicting fish and human exposure to Heavy metals via macro-invertebrates.