The relationships between heavy metals (As, Cd, Cu, Zn, Pb, Hg, Ni) levels and the size of pharaoh cuttlefish (Sepia pharaonis) from Persian Gulf

Concentrations of both essential (Zn and Cu) and non- essential (As, Cd, Pb, Hg, Ni) metals were measured in the organs (mantle, branchial hearts, gill and digestive gland) of Sepia pharaonis captured in the coastal waters of Bushehr Province in the Persian Gulf (Iran). The relationships between S. pharaonis size (mantle length) and metal concentrations in tissues were investigated by linear regression analysis. Metal concentrations (As µg g-1 d.w.) was highest in the digestive gland and lowest in the mantle of S. pharaonis, except for Ni. The concentrations of metals were found to follow the order: Zn > Cu > Pb > Ni > Hg > Cd > As. The mean Zn concentrations ranged from 37.72± 5.32 to 9.32± 3.73 µg g-1 d.w, whereas the mean As concentrations ranged from 0.01± 0.007 to 0.06± 0.05 µg g-1 d.w, respectively. Results of linear regression analysis showed that significant relationships between metal concentrations and fish size were positive, except for cadmium concentrations in the gills. The digestive gland of S. pharaonis would seem to constitute a good potential indicator of heavy metal concentrations in the marine environmental. Results from this study revealed that except for Pb the concentration of metals in S. pharaonis samples were below the threshold values As recommended by the FAO and EC guidelines.