This report is a synthesis of data concerning PCB concentrations in water, sediments and organisms (Bivalvia, Malacostraca, Pisces). Water analysis shows that Seine River is the primordial factor affecting PCB dispersion in the bay. Sediment contamination is higher near estuary along Calvados coast. PCB levels in Mytilidae and in Pectinidae set the problem of polluant origin, dispersion and effects on estuarine organisms.