A non-lethal multi-biomarker approach to investigate the ecotoxicological status of Mediterranean loggerhead sea turtle (Caretta caretta, Linneo, 1758)

In this study we present a non-lethal multi-biomarker methodological approach developed and applied to study the ecotoxicological status of the Mediterranean population of loggerhead sea turtle (Caretta caretta, Linneo, 1758). In the last 8 years more than 120 specimens of C. caretta were sampled for blood, skin biopsies and carapax sub-samples in several Italian rescue centers and during a survey in Spain. Blood lymphocytes and skin biopsy slices treated with different contaminants (OCs, PAHs and PBDEs) showed induction of cytochrome P450 1A (WB) and this biomarker of exposure to liposoluble contaminants was subsequently applied to C. caretta sampled in the different areas. Oxidative stress responses were evaluated on plasma samples by developing a plasma lipid peroxidation (LPO) test which showed a correlation to CYP1A. Potential genotoxic effects were investigated by developing comet assay and ENA (erythrocytic nuclear abnormalities) test in whole blood samples. Biomarkers of hepatic stress such as ALT AST and γ- GT were measured in plasma. Possible estrogenic effects were investigated by measuring plasma levels of vitellogenin by ELISA and WB, including investigation of females during eggs deposition. Butyrylcholinesterase activity was detected in plasma as biomarker of neurotoxicity. The possible relation between biomarkers and contaminant levels in blood (PAHs and OCs) and carapax (trace elements) was investigated. Biomarker and contaminant level results were also elaborated by classes of age. The information obtained in this research represents a strong contribution for the development of a complete protocol of analysis for the monitoring and protection of this endangered species, highly stressed in Mediterranean Sea.