Presence of Heavy Metals in Muscle, Bone, Skin, and Carapace of Chelonia mydas and Lepidochelys olivacea

This study analyzes bioaccumulation of heavy metals in hatchlings of two sea turtle species in Mexico: the olive ridley turtle (Lepidochelys olivacea) in Guerrero and the green turtle (Chelonia mydas) in Veracruz. Heavy metals-including Ag, As, Cd, Hg, and Pb-pose a significant threat to marine ecosystems, as they do not degrade and are biomagnified along the food chain, causing severe disorders such as respiratory failure, infertility, and neurotoxicity. Using inductively coupled plasma mass spectrometry (ICP-MS), 28 metals were identified in different tissues (bone, muscle, skin, and carapace). Lepidochelys olivacea showed a higher total elemental load, especially in skin and carapace, whereas Chelonia mydas exhibited greater accumulation in muscular and calcified tissues. Cadmium (Cd) was found exclusively in C. mydas, while ruthenium (Ru) and tantalum (Ta) were detected only in L. olivacea. Statistical analysis (ANOVA) revealed significant differences in bioaccumulation in bone and carapace between the two species, suggesting that these calcified tissues act as principal reservoirs of trace elements. These differences are likely attributable to their contrasting diets-herbivorous in C. mydas and omnivorous in L. olivacea-and to variations in environmental exposure. The presence of lead (Pb) and palladium (Pd) indicates an anthropogenic impact associated with urban and industrial activities. Overall, sea turtle hatchlings emerge as key bioindicators of coastal pollution and highlight the urgent need for mitigation strategies to protect these endangered species.