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

Abstract

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 pharaoniscaptured in coastal water of Bushehr Province on thePersian Gulf (Iran). The relationships between S. pharaonis size (mantle length) and metals concentrations in tissues were investigated by linear regression analysis. Metals concentration (as µg/ g 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 d.w, whereas the mean As concentrations ranged from 0.01± 0.007 to 0.06± 0.05 µg/ g d.w, respectively. Results of linear regression analysis showed that significant relationships between metal concentrations and fish size were positive, except for the cadmium in the gill. Levels of metals determined in mantle of the Pharaoh cuttlefish were within the range of value legally defined as safe for human consumption, except forPb. The digestive gland of S. pharaonis would seem to constitute a good potential indicator of heavy metal concentrations in the marine environmental.