Frequency dependant susceptibility of dried grab samples from the navigation channel and the Bay of Seine

To estimate the contribution of submicron-size superparamagnetic particles to the susceptibility signal, frequency-dependant susceptibility at 976 and 15.616 Hz was determined on 11 samples originating from the whole study area (i.e. dumping sites, Seine estuary, near-coastal areas, dredging sites) at t0, t1, t2 and t3.