Metals and Metalloids in the Carapace of Hawksbill (Eretmochelys imbricata) and Green Turtles (Chelonia mydas) Nesting in the Southern Gulf of Mexico

Keratin matrixes are a highly relevant tissue for measuring and evaluating the accumulation of endogenous and exogenous substances across a wide variety of species. In this context, the carapace of marine turtles is a valuable source of information. In this study, we collected carapace samples from two species of marine turtles to analyze metals and metalloids. Nine elements (As, Ag, Cd, Cr, Cu, Fe, Pb, Mn, Zn) were measured, with Zn, Pb, Fe, Cu, and As being the elements that showed the highest concentrations. Significant correlations were observed in Green Turtles between morphometric variables and elements such as Ag (carapace width) and Cu (body mass). In Hawksbill Turtles, these variables demonstrated correlations with Ag. No significant differences were found between species except for Cu concentrations. Our study demonstrates that the carapace of sea turtles is a valuable tissue in the research and conservation efforts for these species. It has generated new information on the accumulation of pollutant elements (metals and metalloids) in keratinized matrixes and will be helpful in evaluating their long-term exposure.