We sampled eighteen stations in the lagoon and nine in the canals of the industrial area of Porto Marghera. At each lagoon site a short core, 10 cm long, was taken and immediately extruded to obtain four slices 2.5 cm thick. Surficial sediment samples from the canals were 28 cm thick. Samples were analysed for As, Cd, Hg, Pb and Zn after acid extraction.Maximum values are seen in sediments taken from the oldest part of the industrial area (up to 132, 70, 48, 929, 8295 mg g for As, Cd, Hg, Pb and Zn, respectively), whereas the highest concentrations in the lagoon are much lower (25, 5.0, 2.3, 114, 1115 mg g for As, Cd, Hg, Pb and Zn, respectively).Metal distributions are not driven by sediment characteristics, such as grain size composition and organic carbon content: the strong gradients reflect the relative importance of the sources.In fact, a series of factories have been treating minerals for many years for the production of metals and chemicals.Concentration depth profiles in lagoon sediments suggest that the contamination is decreasing, thus confirming the trends shown by previous core data.Since the release of metals from the industrial plants has been reduced, the polluted sediments stored in the industrial canals are presently the most likely source of toxic metals to the lagoon environment.The influence of this source can be seen in the still high levels found in the lagoon sample closest to the industrial area.
Distribution of heavy metals in sediments of the Venice Lagoon: the role of the industrial area
Bellucci LG;Frignani M;
2002
Abstract
We sampled eighteen stations in the lagoon and nine in the canals of the industrial area of Porto Marghera. At each lagoon site a short core, 10 cm long, was taken and immediately extruded to obtain four slices 2.5 cm thick. Surficial sediment samples from the canals were 28 cm thick. Samples were analysed for As, Cd, Hg, Pb and Zn after acid extraction.Maximum values are seen in sediments taken from the oldest part of the industrial area (up to 132, 70, 48, 929, 8295 mg g for As, Cd, Hg, Pb and Zn, respectively), whereas the highest concentrations in the lagoon are much lower (25, 5.0, 2.3, 114, 1115 mg g for As, Cd, Hg, Pb and Zn, respectively).Metal distributions are not driven by sediment characteristics, such as grain size composition and organic carbon content: the strong gradients reflect the relative importance of the sources.In fact, a series of factories have been treating minerals for many years for the production of metals and chemicals.Concentration depth profiles in lagoon sediments suggest that the contamination is decreasing, thus confirming the trends shown by previous core data.Since the release of metals from the industrial plants has been reduced, the polluted sediments stored in the industrial canals are presently the most likely source of toxic metals to the lagoon environment.The influence of this source can be seen in the still high levels found in the lagoon sample closest to the industrial area.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
