Discriminative influence of persistent organic pollutants on nesting green sea turtles through genotoxicity, oxidative stress and reproductive related markers

Persistent organic pollutants (POPs) including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochloride pesticides (OCPs) affect biodiversity by bioaccumulating through food webs, impacting marine organisms like endangered sea turtles. This study represents the first evaluation of these contaminants in sea turtles nesting in São Tomé and Príncipe. The main goal was to evaluate PCBs, PBDEs and OCPs levels in sea turtles' blood and investigate their potential effects on erythrocytic nuclear abnormalities (ENAs) and oxidative stress and reproduction-related gene expression. The relative mean abundance for contaminants was ΣPCBs > ΣOCPs > ΣPBDEs. Contaminants such as PCB-28, PCB-138, PCB-153, PCB-180 and p,p’-DDE were associated with ENAs, suggesting potential genetic instability and cellular disruption. PCB-126, PBDE-100, and o,p’-DDD correlated with antioxidant and detoxification genes (glrx3, gst, txnip, txnrd2, and gclc), suggesting oxidative stress responses. The reproduction-related gene est17 was correlated with α- and β-HCH, potentially affecting ovary development. Correlations between ace2 and various PCBs, PBDEs, and o,p′-DDD suggest disruptions in follicular development and egg transport. Embryo development genes (hoxA1 and tuba1) were associated with PBDE-154, PBDE-100 and o,p’-DDD, suggesting possible embryonic alterations. These findings highlight the impacts of POPs on nesting female green turtles in São Tomé, threatening this endangered population.