Correspondences between hydrology and particulate metal concentrations along Mediterranean vertical profiles

Results concerning the vertical profiles of some heavy metal concentrations in Mediterranean suspended particulate matter, collected during an oceanographic cruise (May-June 1991), are discussed. The chemical analyses were carried out according to plasma atomic emission spectroscopy, The research was completed with hydrological data, which indicate Levantine Intermediate Water to be present. Correspondences between temperature and salinity profiles and chemical results pointed out that, in some cases, the heavy metals concentration in the particulate matter (mu g g(-1) of particulate, dry weight) could be a tracer, together with hydrological parameters, when studying the displacement of seawater masses. In fact, in correspondence with the Levantine layer, in two stations the heavy metal concentration average values are greater than the average values relative to surface and deep layers, and in;three stations, 'unusual' correlations between some metals in the intermediate layer confirm the presence of a different kind of particulate matter. (C) 1997 Elsevier Science Ltd.