Tracing environmental contaminants in magellanic penguins: Legacy POPs and metabolic clearance of PAHs.

Persistent organic pollutants (POPs) are widespread contaminants that bioaccumulate in the food web, posing risks to wildlife, especially top predators. This study investigates the occurrence of POPs in liver tissues of 23 Magellanic Penguins (Spheniscus magellanicus) stranded along the Brazilian coast from June to September 2017. We analyzed concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (DDTs, Drins, mirex, endosulfans), and hexachlorobenzene (HCB). POPs were detected in all samples. PCBs and DDTs showed the highest concentrations, with PCBs ranging from < LOD to 199.4 ng g-1 ww (mean: 57.2 ± 49.0 ng g-1 ww), showing a declining trend compared to previous reports. DDT metabolites, especially p,p'-DDE, remained persistent in the samples. HCB was found in 70% of the individuals but at lower levels than previously reported. Other pesticides were present at trace levels, consistent with their historical use in Brazil. No polycyclic aromatic hydrocarbons (PAHs) were detected, which we attribute to rapid metabolic clearance in penguins rather than lack of exposure. This emphasizes the species' efficiency in eliminating these non-persistent compounds. Our findings highlight the continued presence of legacy POPs in the marine ecosystem and their bioaccumulation in seabirds. Although PCB levels appear to be decreasing, these pollutants still pose ecological risks. Monitoring efforts remain essential, especially considering the potential for re-exposure due to global distillation and melting of polar ice. This study contributes to understanding contaminant dynamics in the Southern Hemisphere and underscores the importance of long-term monitoring of marine wildlife.