Polycyclic aromatic hydrocarbons in oysters from Amazonian protected reserves: occurrence, tissue distribution and...

This study provides the first baseline data on PAHs in the mangrove oyster Crassostrea gasar from contrasting production systems in two Brazilian Amazon conservation areas, including submerged aquaculture in Augusto Corrêa and aquaculture and intertidal natural banks in Curuçá. Mantle, gill, and visceral mass showed Σ16PAHs concentrations from 5.0 to 45.6 ng g^-1 dry weight, with low molecular weight PAHs accounting for 77% of the total burden. Σ16PAHs concentrations in the mantle and visceral mass tended to be higher than in gills, indicating preferential accumulation in metabolically active tissues. Wild oysters from natural banks exhibited the highest Σ16PAHs concentration, with tissue partitioning patterns likely related to prolonged sediment-associated exposure. Farmed oysters showed low contamination and no significant differences between farming sites. Concentrations of high molecular weight PAHs and benzo[a]pyrene toxic equivalency remained below regulatory thresholds for all samples, indicating no carcinogenic risk associated with oyster consumption. PAH accumulation profile in wild oysters highlights the importance of environmental monitoring to ensure the long-term sustainability and consumer safety in this ecologically and socioeconomically relevant region.