Bioaccumulation of polycyclic aromatic compounds: 1. Bioconcentration in two marine species and in semipermeable membrane devices during chronic exposure to dispersed crude oil

Assessing the fate in marine biota of hydrocarbons derived from oil particl es that are discharged during exploration and production is of relevant env ironmental concern. However, a rather complex experimental setup is require d to carry out such investigations. In this study, a sophisticated tool, th e continuous-flow system (CFS), was used to mimic dispersed oil exposure to marine biota. Polycyclic aromatic hydrocarbon (PAH) uptake was studied in two species, the blue mussel Mytilus edulis and juvenile of the turbot Scop hthalmus maximus, and in semipermeable membrane devices (SPMD) exposed to c rude oil dispersed in a flow-through system. After an exposure period of 8 to 21 d, elimination in organisms and devices was analyzed for 9 to 10 d fo llowing transfer to PAH-free seawater. Principal component analysis (PCA) r evealed different PAH patterns. In mussel and SPMD, the PAH profiles were v ery close to that analyzed in seawater. Slight differences were, however, i ndicated for large molecules with long K-ow above six. Nonachievement of st eady-state concentration and bioavailability of PAH in oil droplets may acc ount for these differences. The PAH composition in fish revealed only conge ners with two to three aromatic rings. A combination of bioavailability and efficient metabolism of the larger PAH molecules may explain this pattern. The CFS made possible a better understanding of some critical factors gove rning bioconcentration in marine biota from dispersed oil. Yet the results illustrate that uptake of PAH from exposure to oil particles is complex and that different species may bioconcentrate different molecules depending on factors like life style and metabolic capability to degrade the potential harmful substances. Hence, risk assessment of the actual impact of discharg es to marine biota should consider these essential biological and ecologica l factors.