Bioaccumulation and metabolisation of 14C-pyrene by the Pacific oyster Crassostrea gigas exposed via seawater

► Waterborne pyrene was rapidly accumulated and eliminated by the oysters. ► Gills played a major role in the incorporation of dissolved pyrene. ► Oysters displayed a limited capacity of metabolisation of pyrene. ► Oysters appear as a good bioindicator organism to survey pyrene contamination. The first objective of this study was to determine the bioaccumulation kinetics of pyrene in the soft tissues of Crassostrea gigas (mantle, muscle, gills, digestive gland, and the remaining soft tissues). As bivalves can biotransform hydrocarbons in more polar compounds (metabolites) that are more easily excreted, the second objective was to investigate the oyster capacity to metabolize pyrene into its metabolite, the 1-hydroxypyrene. To these ends, oysters were exposed 24h to waterborne 14C-pyrene then placed in depuration conditions for 15d. Oysters efficiently bioaccumulated pyrene in their soft tissues and equilibrium was reached within the exposure time. The metabolite1-hydroxypyrene was also detected in oyster tissues but represented only 4–14% of the parent pyrene. At the end of the exposure period, the gills and the mantle showed the highest pyrene proportion of total soft tissue content, i.e. 47% and 26%, respectively. After 15d of depuration, the mantle contained 32% and 30% of the remaining pyrene and 1-hydroxypyrene, respectively. As C. gigas did not display a high capacity for metabolizing pyrene, it can be considered as a good bioindicator species to survey and monitor pyrene contamination in the coastal marine environment.