Metals in Blood and Eggs of Green Sea Turtles (Chelonia mydas) from Nesting Colonies of the Northern Coast of the Sea of Oman

Abstract

The green sea turtle (Chelonia mydas) has been a species of global concern for decades. In this study, heavy metals (mercury: Hg; Cadmium: Cd; Lead: Pb; Copper: Cu; and Zinc: Zn) were measured in blood and three egg fraction of green sea turtles nesting on the northern coast of Sea of Oman. Heavy metals concentrations in blood, yolk, albumen, and egg shell ranged between 0.16–36.78, 0.006–33.88, 0.003–4.02, and 0.002–6.85 μg/g (ww), respectively. According to the results, all heavy metals found in blood samples (n = 12) also were detected in the various parts of the eggs (n = 48). Moreover, there were no significant differences between concentrations of heavy metals in different clutches laid in a nesting season. However, Pb concentrations in blood samples significantly increased in later clutches (p < 0.05), whereas Cu concentrations in blood samples exhibit a declining trend (p < 0.05). These results reveal the existence of maternal transfer phenomenon in green sea turtles on the northern coast of Sea of Oman. Results of this study suggest that heavy metals could be one of the factors influencing reductions in fertilization and hatching success. Results also indicate that green sea turtle on the northern coast of Sea of Oman have high capacity in rapid response and detoxification of heavy metals and/or from the low exposure levels of these turtles to the heavy metals. Further research is required concerning the effects of heavy metals on green sea turtles, especially on their possible influence of fetal development of turtles.