Oil ingestion and genotoxic biomarkers in three swimming crab species (Decapoda, Portunidae) from tropical estuaries affected by oil spills.

The 2019 oil spill along the Brazilian coast represents one of the largest marine contamination events in the region, with evidence of long-term persistence and re-emergence of residues in subsequent years. This study primarily reports the ingestion of oil residues by three swimming crab species (Callinectes danae, C. exasperatus, and C. marginatus) from tropical estuaries in northeastern Brazil following oil resurgences recorded in 2022. Specimens were collected in three estuaries (Atapuz, Suape, and Carneiros) between 2022 and 2023. Oil-like fragments retrieved from stomach contents were characterized using Raman spectroscopy, while polycyclic aromatic hydrocarbons (PAHs) were quantified in mangrove sediments. Genotoxic damage was assessed as a complementary endpoint through micronucleus frequency (MN%) in hemolymph cells. Raman spectral profiles confirmed that ingested fragments are consistent with residues of oil associated with materials re-emerging in 2022. Oil ingestion was widespread and increased over time, reaching 78.9% of individuals in 2023, with C. danae showing the highest occurrence. Despite the high frequency of ingestion, sediment PAH concentrations were low (<100 ng g-1) and showed no correlation with the presence of oil in stomach contents. Genotoxic damage was detected across all species and sites; however, no significant differences were observed between individuals with and without oil ingestion. These findings provide direct evidence of the incorporation of petroleum-derived material into estuarine food webs years after the initial spill, highlighting the persistence and bioavailability of oil residues. The results emphasize the importance of monitoring ingestion pathways to better understand long-term ecological exposure in impacted coastal systems.