| Abstract
| - The aim of this study was first to assess the relevance ofa marine sponge, Spongia officinalis, as a biomonitor ofPCB. Twenty-four chlorobiphenyl congeners have beenmeasured along a pollution gradient both in sponges andseawater. S. officinalis displays a capacity to accumulateall types of congeners. The highest concentration factorswere found for hexa- and heptachlorobiphenyls. Concentrations recorded in sponges agreed quite well withthe PCB concentrations of study sites. The prevalence ofCB138 and CB153 definitely demonstrated the urbanorigin of the PCB detected, despite the ban on theirproduction and the existence of a wastewater treatmentplant since 1987. The CB138/CB153 ratio is ∼1.2 in commercialmixtures as well as in seawater. In sponges, this ratiovaries strongly in space and time, from 1 in sponges at themost polluted site to 0.3 at the reference site. Thischange in the ratio of these two very persistent congeners,which is not observed in seawater, indicates a metabolismof CB138 in sponges. As it was recently demonstratedfor nonpersistent organic contaminants, sponges might wellbe able to degrade PCB, but further work is needed toidentify the processes involved.
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