Dredged sediments may contain considerable amounts of metallic and/or organic pollutants. The risk of metal transfer from sediment deposits to soils can be evaluated using chemical extraction procedures; however, the temperatures at which samples are dried before metal extraction vary widely from one study to another. This led us to investigate the impact of drying temperature on the extractability of metals from dredged sediments. First, water-, CaCl 2 -and DTPA-extractions were performed on 12 dredged sediments collected in France, with analyses being carried out on both raw (i.e. not dried) samples and on samples dried at 105 • C. Higher extractable Cd and Zn contents were recorded for the samples dried at 105 • C than for the raw samples. In order to assess the effect of drying temperature on metal extractability, we selected one sediment and carried out CaCl 2 -, HNO 3 -and DTPA-extractions on the raw sample and on samples dried at three different temperatures. In general, increasing the drying temperature led to an increase in the extractability of Cr and Cu for all three extraction methods. The CaCl 2 -extractability of Ni and Zn decreased as drying temperature increased, except for the sample dried at 105 • C. The HNO 3 -and DTPA-extractabilities of these two metals were highest when the sediments were air-dried and then decreased with increasing drying temperature. Similar behavior was observed for Cd, except in the case of HNO 3 -extractability. As the aim of chemical analysis using selective extraction is to measure the bio-available fractions of metals in soils and sediments, we suggest that extraction should be carried out on raw samples in order to simulate plant growth conditions.
La France est un producteur majeur de produit verrier en Europe. La production est très diverse en termes de composition verrière et d’usage : verre sodo-calcique pour les arts de la table, le bâtiment, l’automobile et l’emballage, verre borosilicaté pour les arts culinaires, les emballages pharmaceutiques, les laboratoires, verres spéciaux pour des applications aussi nombreuses que variées… La grande diversité des applications conduit l’industrie du verre à se conformer à de nombreuses réglementations que ce soit sur le produit ou sur le procédé. Avec un taux de recyclage en croissance et de multiples options en cours d’étude pour adapter le procédé à la lutte contre le changement climatique, le verre répond aux enjeux de notre société et reste un matériau innovant et moderne.
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