Determination of metals in tuna species and bivalves from Alexandria, Egypt

The concentration levels of eight heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured in the liver, gills, and muscle tissues of tuna fish (Thunnus thynnus) collected from the El-Mex Bay, the Eastern Harbour and Abu-Qir Bay as well as two bivalves (Pinctada radiate and Paphia textile) from the Abu-Qir Bay. Generally, the liver and gills exhibited higher metal concentrations than the muscle. Among the analysed fish species, the average concentrations of heavy metals were as follows: Cd (0.052, 0.243, 0.177), Cr (0.817, 1.503, 1.196), Cu (1.251, 4.368, 2.711), Fe (165.476, 263.557, 186.405), Mn (1.004, 1.509, 3.031), Ni (0.370, 0.624, 0.708), Pb (0.832, 1.113, 1.372), Zn (18.715, 118.308, 78.421) mg/kg wet weight in the muscle, liver and gill tissues, respectively. The average concentrations of trace metals in mussels decreased in the order Fe (296.655) > Zn (88.222) > Mn (5.497) > Cu (1.299) ⩾ Pb (1.135) ⩾ Cr (1.072) > Ni (0.659) > Cd (0.347) mg/kg wet weight. The concentrations of the studied heavy metals in all species were found to be within the safe limits suggested by various authorities and thus gave no indication of pollution. The target hazard quotients (THQs) values of Cd, Cr, Cu, Mn, Pb, and Zn for the investigated fish and mussels are much smaller than one, which may indicate that there is no health risk from consuming the investigated fish and mussels.