Heavy Metals in Eleven Common Species of Fish from the Gulf of Aqaba, Red Sea

The muscles, livers, gills, gonads, and stomachs of eleven common fish species collected at three sites in the northern Gulf of Aqaba, were analyzed for the heavy metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Large differences in trace metal concentrations (in μg g^(-1) dry weight) were observed between different tissues or organ parts within each fish. In muscle tissue Cd ranged from 0.5 to 2.0 μg g^(-1) dry weight, while higher concentrations were found in liver, gill, and stomach tissues (up to 7.0 μg g^(-1). Cobalt concentrations were lowest in muscles (1.7- 7.1) and livers (1.9-6.8) and highest in gills (4.3-15.0) and stomachs (1.8-11.0). Similarly, Cr concentrations were highest in gills (4.3-44.2) and stomachs (1.8-22.0), and lowest in livers (1.9-11.5). Copper was also low in muscles (0.5-2.0), but highest in liver tissue (6.7-40.6). Iron levels were highest in liver (30-1031) and lower in other organs (3.9-391.0). Muscle tissues contained lower concentrations of Mn (1.0-3.3) than other organs, particularly the gills (3.8-19.0), which contained also higher concentrations of Ni and Pb (4.5-19.2 and 8.7-35.0, respectively) compared to the livers (1.0-11.4 and 1.9-6.3) and muscles (1.0-5.0 and 2.5-8.3). Gonads contained the highest concentration of Zn (77.5-271.7), while muscles contained the lowest (1.9-35.0).