Bioaccumulation of legacy POPs in seabirds: A multi-species comparison between Procellariiformes and Suliformes in...

This study examines the presence and distribution of persistent organic pollutants (POPs) in the liver tissues of six Procellariiformes species collected from beach-cast individuals along the Rio Grande do Sul coast during their migration in the South Atlantic and the blood of brown booby (Sula leucogaster) sampled from a resident breeding population at the São Pedro and São Paulo Archipelago. POPs, including PCBs, DDTs, and Mirex, pose significant threats to marine ecosystems due to their persistence and bioaccumulative nature. Procellariiformes, such as albatrosses and petrels, and Suliformes, such as Sula leucogaster, are particularly vulnerable due to their high position in the food webs and high longevity. This study assesses the relative contributions of different POPs, identifies shifts in contamination profiles, and explores ecological factors driving variations in POP concentrations. Among Procellariiformes, no statistically significant differences were detected in POP concentrations between the taxonomic groups, suggesting shared exposure pathways in overlapping marine habitats. However, Shearwaters exhibited higher median PCB and Mirex levels compared to other groups. In contrast, S. leucogaster displayed a distinct contamination profile dominated by PCBs and DDTs, reflecting its specific foraging behaviors and tropical habitat. The predominance of highly chlorinated PCB congeners in S. leucogaster and Procellariiformes suggests long-range atmospheric transport as a significant source of contamination. These findings highlight the ecological role of multiple species of seabirds as sentinel species and underscore the need for ongoing monitoring of legacy POPs in tropical and subtropical ecosystems to inform conservation strategies.