Polycyclic aromatic hydrocarbons in tissues of sea turtles stranded on oil impacted beaches in Northeastern Brazil

Exposure to and consequent bioaccumulation of toxic hydrocarbons, particularly polycyclic aromatic hydrocarbons (PAHs), are a significant concern for ocean health. This study reports the distribution of parental and alkylated PAHs in the liver and muscle tissues of sea turtles found stranded on locations in the NE coast affected by the largest oil spill in Brazil, which occurred in 2019. The field trips recovered nineteen animals along the shores of Pernambuco, Rio Grande do Norte, and Ceará between 2020 and 2021. Chelonia mydas represented 79% of all specimens. PAH determination in liver and muscle tissues involves extraction using a Soxhlet apparatus, purification by permeation chromatography, and subsequent analysis by gas chromatography/mass spectrometry (GC-MS). Twenty-six of 37 individual PAHs were identified, including parent and alkylated compounds, totaling 67.87 ± 54.22 ng g^-1 (ww) in muscle and 50.19 ± 42.74 ng g^-1 (ww) in liver. Pyrene, phenanthrene, and their respective alkylated homologs were the most abundant PAHs. Tissues showed similar PAH concentrations, but pyrenes were much more abundant in muscle than in the liver. An overall prevalence of light (LMW; 2-3 rings) over heavy (HMW; 4-6 rings) PAHs was verified, particularly in liver samples. The 16 priority PAHs accounted for between 60 and 70% of the total PAHs in both tissues. The findings revealed relatively high contamination, with evidence of exposure to the oil spill in the region and other anthropogenic sources. More importantly, the results can be considered as short- to medium-term exposure indicators following the oil spill in the study areas, and it is essential to monitor the evolution of turtle exposure in the medium- to long-term on the NE coast of Brazil.