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This paper exemplifies the search for historical information on sources, levels, and trends of anthropogenic metals in a zone that has been subject to the influence of multiple industrial sources. Four cores from the canals of the industrial area and one in the lagoon just outside the industrial zone were studied in order to assess the temporal trends of Ag, As, Ba, Cd, Hg, Pb, and Zn. Maximum values were found in the Brentella Canal (4.0, 2315, 41, 5367, 34259 mu g g(-1) for Ag, As, Cd, Pb, and Zn, respectively). High values also characterize the North Industrial Canal (2.2, 120, 70, 49, 929, 8295 mu g g(-1) for Ag, As, Cd, Hg, Pb and Zn) and the Salso Canal. Hg and Ba, the first used as cathode in chlor-alkali plants and the other as a catalyst in the production of trielin, show very high downcore maxima in the Lusore-Brentelle Canal (4901 and 9399 mu g g(-1), respectively). Lagoon sediments show much lower concentrations, with maximum downcore values that are from 11 (Cd) to 2188 (Hg) times lower than within the industrial canals. Chronologies, based on Pb-210 and Cs-137 activity-depth profiles, show that the highest fluxes occurred in the 1970s and early 1980s and that the input of metal contaminated materials is now decreasing. The correlation of some metals with dioxins and furans within the 1st Industrial Area suggests that both these inputs originated from the same series of production processes, active in the first half of the 20th century and starting from pyrite roasting for the production of sulphuric acid.

Flux data from moored sediment trap experiments and mass accumulation rates in sediments were obtained for three sites in the Ross Sea which are currently studied for the formation and transit of High Salinity Shelf Water and Ice Shelf Water. These two data sets were compared to obtain inferences on the coupling between water column processes and sedimentary records.

To better understand the particle exchange processes across the Pyrenean continental margin, sampling was conducted in 1994 and 1995 at stations in and near the Lacaze-Duthiers canyon in the northwestern Mediterranean. Moored current meters provide evidence of water transport along the canyon axis (cross-slope) and along-slope with the prevailing regional circulation. Turbidity measurements show surficial nepheloid layers (SNL) roughly coincident with fluorescence resulting from biological productivity. Recurrent benthic nepheloid layers (BNL) (as observed at a station on the outer-shelf) are advected into the canyon, forming intermediate nepheloid layers (INL). The mineralogical composition of suspended particles collected at stations on the outer-shelf and head of the canyon indicates an illite and chlorite-rich assemblage with minor magnesian calcite, indicative of materials resuspended from the adjacent shelf sediments. The mineralogy of suspended particles at stations farther in the canyon shows the presence of material derived from the Rhone River and likely transported along-slope by the Liguro-Proven-cal current. Measurements of the short-lived naturally occurring radionuclide 234Th show that it is actively scavenged from the nepheloid layers. Within the canyon, scavenging (as indicated by the mean residence time of dissolved Th with respect to uptake onto particles) is similar in both the SNL (30–58 d) and INL (25–85 d). Residence times of particulate Th with respect to removal from the water column follow the same trends, with values of about 5 d (1994) and 12–19 d (1995) in the SNL and 11–20 d (1994) and 15–23 d (1995) in the INL. This research suggests that while the Lacaze-Duthiers canyon serves as a conduit through which sediment associated with nepheloid layers detached from the shelf are transported, the rates of scavenging of Th in the canyon are not appreciably different from those on the adjacent shelf.