Trace element levels in fish from clean and polluted coastal marine sites in the Mediterranean Sea, Red Sea and North Sea

The bioaccumulation of Hg, Cd, Zn, Cu, Mn and Fe was evaluated in the muscl e and liver tissue of four fish species (Siganus rivulatus, Diplodus sai-gu s, Lithognatus mormyrus and Plathychtis flesus) from clean and polluted mar ine coastal sites in the Red Sea, Mediterranean Sea and North Sea within th e framework of the MARS I program. Representative liver samples were screen ed for organic contaminants (DDE, PCBs and PAHs) which exhibited very low c oncentrations. The levels of Cd, Cu, Zn, Fe and Mn found in the muscle tiss ue in this study were similar among the four species and within the natural ly occurring metal ranges. However, differences were found among the sites. In the Red Sea, Cu was higher in the muscle of S. rivulatus at Ardag and Z n at the Observatory (OBS). Cu, Zn and Mn were higher in the Red Sea than i n the specimens from the Mediterranean. The differences were attributed to different diets derived from distinctively different natural environments. D. sargus from Haifa Bay (HB) had higher Cd, Cu and Mn values than specimen s from Jaffa (JFA), and L. mormyrus higher Cd, Fe and Mn in HE, correspondi ng to the polluted environmental status of the Bay. No differences in metal levels were found among the North Sea sites, except for Fe that was lower at the Elder station. Hg was low in all the specimens, but the values varie d with species and sites. The lowest Hg values were found in S. rivulatus, the herbivorous species, as expected from its trophic level. Hg in P. flesu s was higher than in S. rivulatus but still low. Higher Hg values were foun d in the muscle tissue of L. mormyrus, with the highest values in D. sargus , both carnivorous species from the same family. Hg in D. sargus was higher in HE than in JFA, as expected, but in the larger specimens of L. mormyrus from JFA values were higher, while in the small specimens there were no di fferences in Hg values. The levels of all metals were higher in the liver t han in the muscle, with enrichment factors ranging from 3 to 104, depending on species and sites. The lowest enrichment values were found for Hg. Base d on liver values, the specimens of S. rivulatus from the OBS had the highe st levels, as well as D. sargus and L. mormyrus from JFA, contrary to the k nown relative environmental status of the sites.