Polycyclic aromatic hydrocarbons (PAHs) in the non-bleached and bleached corals and their ambient environment: The role of suspended particulate matter, mucus, and positive matrix factorization model for identifying contributions to the carcinogenicity of PAH sources

Abstract

This study investigates levels of polycyclic aromatic hydrocarbons (PAHs) in the corals (tissue, skeleton, zooxanthellae, mucus) and their ambient environment (surface sediment, seawater, suspended particulate matter (SPM)), with a special focus on SPM and mucus. The Σ37PAH concentrations ranged from 89 to 206 ng g−1 dw in SPM, 52 to 116.1 ng g−1 dw in the sediment and from 18.6 to 91.9 ng L−1 in the seawater. Among the coral components, mucus contained the highest PAH loadings reaching up to 369.2 ng g−1 dw. Coral morphology and pollution of their ambient environment were identified as the main factors affecting the PAH bioaccumulation. Massive corals T. reinformes and P. compressa living in heavier polluted sites accumulated the highest PAH concentrations. Diagnostic ratios provided inconsistent source apportionment results, but positive matrix factorization (PMF) analysis identified gasoline/diesel (vehicle) emission (F1), oil spills (F2), coal (F3), and wood (F4) combustion as the main PAHs sources in the study area. Contribution to carcinogenic potencies of PAHs in sediment samples decreased in the following order: F1 > F2 > F3. Factor F4 did not affect the carcinogenic properties of the surface sediment samples but was found to contribute significantly to the TEQBaP values of the SPM samples. The results of this study indicate a direct interaction between SPM and the coral mucus and imply that SPM plays an important role in the pollution transfer and bioaccumulation processes in corals.