Input of particulate heavy metals from rivers and associated sedimentary deposits on the Gulf of Lion continental shelf |
| |
| Authors: | Olivier Radakovitch Vincent Roussiez Patrick Ollivier Wolfgang Ludwig Christian Grenz Jean-Luc Probst |
| |
| Institution: | 1. CEREGE – Université Paul Cézanne Aix-Marseille III – CNRS BP 80, 13545 Aix-en-Provence, France;2. CEFREM, CNRS-Université de Perpignan, 52, Avenue Paul Alduy, 66860 Perpignan, France;3. COM, Station Marine d''Endoume, Rue de la Batterie des Lion, 13007 Marseille, France;4. INP, ENSAT, Av Agrobiopole, BP 107, 31216 Castanet Tolosan, France |
| |
| Abstract: | Fluxes of the heavy metals chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), lead (Pb), cadmium (Cd) and zinc (Zn) delivered by rivers to the Gulf of Lion (NW Mediterranean Sea) were estimated over a three year study of the River Rhone and its smaller tributaries. Most of the particulate metal fluxes (80–90%) delivered by these rivers occurred within a very short period of time (less than 12%), a typical trend for the Mediterranean environment, where highly contrasting hydrological regimes were observed over the year. Temporal and spatial variations in the fluxes of these particulate metals were driven by the fluxes in both water discharge and suspended particulate matter load. On the shelf, these particulate metal fluxes, largely arising from the Rhone watershed, were two to ten times more important than those resulting from atmospheric deposition. Co, Cr and Ni in the rivers and on the shelf surface sediments were mainly natural and associated with the finest particles. Cd and Phosphorus appeared to be associated with the silt fraction and to be enriched in the prodelta areas. Pb, Zn and Cu were more closely associated with the organic matter content and also showed enrichment in the organic rich prodeltaic sediments. Anthropogenic influences diminished offshore, except for Pb and Zn which could be supplied from the atmosphere by man-made aerosols. Although most of the metals tended to be enriched in the prodelta areas, these did not constitute a permanent sink due to resuspension processes affecting these shallow depths. A resuspension experiment conducted on sediment cores from the Rhone prodelta demonstrated that metal deposited on the surface layer, especially those associated with the organic matter, may be resuspended; this should be taken into account for a complete understanding of the biogeochemical cycle of these metals. |
| |
| Keywords: | heavy metals sediment contamination river inputs Mediterranean Sea prodelta sediment resuspension |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
