Lead in blood and eggs of the sea turtle, Lepidochelys olivacea, from the Eastern Pacific: Concentration, isotopic composition and maternal transfer

Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea, from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the “arribada” event of the 2005-2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95 ± 0.18 μg g−1) and egg samples (yolk, 0.80 ± 0.10 μg g−1; albumen, 1.08 ± 0.20 μg g−1; eggshell, 1.05 ± 0.20 μg g−1) were comparable or even lower than those found in other sea turtles. The isotope ratios (206Pb/207Pb and 206Pb/208Pb) in blood (1.183 ± 0.0006 and 2.452 ± 0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188 ± 0.005 and 2.455 ± 0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment.