Metallothionein biosynthesis as a detoxification mechanism of heavy metals (Hg,Cd,Pb,Cu,Zn) in green sea turtles (Chelonia mydas)

In this study, heavy metals (Hg,Cd,Pb,Cu,Zn) and metallothionein (MT) biosynthesis were measured in blood of green sea turtles (Chelonia mydas) nesting on the northern coast of the Sea of Oman. Heavy metals concentrations in the sea water, the sediments, the blood samples ranged between 0.02-8.43 μg/l, 0.06-10.32 μg/l, and 0.16-36.78μg/g (ww), respectively.The highest concentration of heavy metals were measured at Ahmad rizeh followed by Ramin>Lipar >Kacho> and Tang Provinces. The concentrations of heavy metals in the coastal water and sediment were as follows; Zn>Cu>Pb>Cd>Hg. There were no significant differences between concentrations of heavy metals in different clutches laid in a nesting season. The lowest MT biosynthesis was recorded (115.7 ± 18. 12 μg/g dry weight) at the Tang sampling sites, while the highest was registered (276.4 ± 22.18 μg/g dry weight) at the Ahmadrizeh. The relationship between metallothionein biosynthesis and heavy metals in the blood samples, the sea water and the sediment were significant (p<0.05). Significant relationship was found between biomarker and heavy metals in this study, which indicates that green sea turtle (C. mydas) have high capacity in rapid response and detoxification of heavy metals on the northern coast of the Sea of Oman. The biomarkers measured in this study were useful as a first investigation into the biological effects of heavy metal pollution, as well as in determining the bioavailability of pollution.