Bioaccumulation of heavy metals in African red snapper (Lutjanus agennes) and cassava fish (Pseudotolithus senegalensis) caught off the Coast of Accra, Ghana

Abstract

The level of Cu, Fe, Mn, Pb, and Zn in African red snapper (Lutjanus agennes) and cassava fish (Pseudotolithus senegalensis) caught off the coast of Accra, Ghana, were monitored from November 2011 to March 2012 using atomic absorption spectrophotometry. Over the five months period, variations occurred in the level of each of the heavy metals in each of the fish species. The heavy metals accumulated in the gills and bones more than in the muscle tissues of type of fish. The order of accumulation of the heavy metals in African red snapper in terms of magnitude were Zn>Pb>Fe>Mn>Cu in the bones, Fe>Zn>Pb>Mn>Cu in the gills and Fe>Pb>Zn>Mn>Cu in the muscle tissue. For cassava fish the order was Fe>Zn>Pb>Mn>Cu in the bones, Fe>Pb>Zn>Mn>Cu in the muscle, and Fe>Pb>Zn>Mn>Cu in the gills. In the muscle tissue, the part of fish which is normally consumed, the mean value for the various heavy metals over the five months period in the African red snapper were Cu, 0.73 mg/kg; Fe,; 8.18 mg/kg Mn, 0.66 mg/kg; Pb, 7.04 mg/kg; and Zn, 5.16 mg/kg. In cassava fish, the mean values in the muscle tissues were Cu, 0.53 mg/kg; Fe, 9.38; Mn, 0.67 mg/kg; Pb, 5.90 mg/kg; Zn, 6.18 mg/kg. The concentrations of the heavy metals found in both fish species were mostly above the safe limits recommended by WHO