PAHs in Arcachon Bay, France: Origin and biomonitoring with caged organisms

The concentration of polycyclic aromatic hydrocarbons (PAHs) has been determined in superficial sediments and caged mussels (Mytilus galloprovincialis) of Arcachon Bay, France. The bay sediments are uniformly contaminated at moderate to high levels (900–4100 ng g−1), with a lower contamination level at the entrance to the bay (≈ 30 ng g−1). This pollution is mainly pyrolytic and related to anthropogenic activity. Caged mussels exposed to sediments with a contamination level of <2000 ng g−1 are contaminated at moderate levels (300–500 ng g−1), but those exposed to sediment contaminated at a higher level (> 3000 ng g−1) have accumulated more PAHs ( > 2000 ng/g). This may result from a different equilibrium between uptake and depuration of the xenobiotics at the sites with greater levels of contamination or from higher levels of bioavailability of the contaminants at these locations. The bioavailability of the contaminants is also discussed in terms of organism exposure and contaminant origin.