1,720,991 research outputs found
MERCURY ACCUMULATION IN SEDIMENTS OF THE CENTRAL SECTOR OF MARANO AND GRADO LAGOON (ITALY).
No full textContributo antropico di metalli pesanti e 137Cs nei sedimenti del bacino di Buso (Laguna di Marano e Grado, Italia settentrionale)
No full textIl Bacino di Buso occupa l’area centrale della Laguna di Marano e Grado, situata nell’Adriatico settentrionale. Questi ambienti di transizione presentano un’alta vulnerabilità a causa del pesante impatto antropico dovuto alle attività industriali e agricole che gravano sul bacino lagunare. Inoltre, la laguna di Marano e Grado è stata interessata dal fallout radioattivo a seguito dell’incidente di Chernobyl nel 1986. All’interno del bacino lagunare sono state identificate alcune aree preferenziali di accumulo dei metalli pesanti presi in esame e di 137Cesio. Il grado di arricchimento di alcuni elementi in tracce (Hg, Cr, Zn, Ni e Cu) nei sedimenti attuali è stato confrontato con i tenori degli stessi nei sedimenti di età preindustriale. I tenori di Hg risultano fino a 18 volte superiori ai valori di background naturale. I profili di arricchimento per questo metallo nelle carote hanno evidenziato la persistente contaminazione nel tempo
MERCURY PHASES IN MARANO LAGOON (NORTHERN ADRIATIC SEA, ITALY): A TOOL TO IDENTIFY DIFFERENT SOURCES OF HG POLLUTION.
No full textVariabilità tessiturale e distribuzione dei sedimenti superficiali nel Golfo Saline (Sardegna Settentrionale)
No full textMercury contamination in Marano Lagoon (Northern Adriatic sea, Italy): source identification by analyses of Hg phases
No full textTotal Hg concentrations and Hg speciation were determined in bottom sediments of Marano lagoon to investigate the consequences of Hg phases on Wsh farms and shellWsh cultivation areas. Mercury phases were separated into cinnabar
(HgS) and non-cinnabar compounds, via a thermo-desorption technique, in surface and core sediments; both of which had been contaminated by industrial wastes and mining activity residues. The former are due to an industrial complex, which has been producing cellulose, chlor-alkali and textile artiWcial Wbres since 1940. Processing and seepage wastewaters, which were historically discharged into the Aussa-Corno river system and therefore into the lagoon, have been signiWcantly reduced since 1984 due to the construction of wastewater treatment facilities. The second source is the Isonzo River, which has been the largest contributor of Hg into the northern Adriatic Sea since the 16th century due to Hg mining at the Idrija mine (western Slovenia). Red cinnabar (HgS) derived from the mining area is mostly stable and insoluble under current environmental conditions. In contrast, organically bound Hg, such as Hg bound to humic acids,
has the potential to be transformed into bioavailable Hg compounds (for example, methylmercury). The presence of the
two Hg forms permitted each Hg source to be quantiWed. It also allowed the areas with the highest risk of Hg contamination from Hg-rich sediment to be identiWed; thus potentially avoiding the transfer of Hg from the sediment into the water column and eventually into living biota. The results show that Hg Enrichment Factors in bottom sediments exceed values of 10 and cinnabar dominates the central sector near the main tidal channel where tidal Xux is more eVective. Non-cinnabar compounds were found to be enriched in Wne grained material and organic matter. In fact, up to 98% of total Hg at the Aussa-Corno river mouth and in the inner margin of the basin occurred in an organic form. This evidence, combined with the high contents of total Hg (4.1–6.6 g g¡1 and EF >10) measured in surface sediments, suggest that Hg in Marano lagoon is involved in biogeochemical transformations (e.g., methylation)
Circulation and suspended matter distribution in a microtidal deltaic system: the Isonzo river mouth (northern Adriatic Sea)
No full textTwo field investigations, under low river flow regime, were conducted in the Isonzo River mouth, Gulf of Trieste, to examine effluent dynamics and suspended sediment characteristics through the water column. The well-marked stratification influences particle size distribution. Multivariate statistical analysis was successfully utilized to define the characteristics and mutual relationships of the water masses in the estuarine zone. The results allow the Isonzo River mouth to be identified as a microtidal, low-energy, fine-grained deltaic system. The highly stratified water column and related hypopycnal flux prevail in the dynamic regime within the lower reach of the distributary mouth. This type of circulation is interrupted during extreme river floods, when the salt-wedge is pushed out of the river mouth
Transport and dispersion of particulate mercury associated to a river plume in coastal Northern Adriatic environments.
No full textThe role of suspended particulate matter (SPM) as an important carrier of mercury (Hg) dispersed into the Gulf of Trieste and in the adjacent Grado lagoon (Northern Adriatic Sea) was studied during a high Isonzo River inflow and the resulting river plume formation. Despite the fact that extreme flood events are rare during the year, they account for most of the PHg influx (37–112 ng Lÿ1) into the Gulf of Trieste. When the river plume is diverted to the SW under the influence of an E–NE wind, the tidal flux acts as a ‘‘transport belt’’ carrying the PHg, mostly inorganic, into the Grado lagoon. A preliminary estimation indicates that the amount of PHg entrapped in the lagoon basin following a tidal semi-cycle accounts for 1.4 kg/12 h, which corresponds to about 49% of the total Hg carried by the tidal flow. These findings should be considered in future remediation strategies in the lagoon environment
Carta tessiturale dell’area marina compresa tra P.ta Sardegna e Capo D'Orso (Sardegna settentrionale)-scala 1:10.000
No full textNel corso delle campagne oceanografiche Paleocli.ge 1999 -2000 e Mirto 2002 sono state studiate, anche dal punto di vista sedimentologico, le aree marine interne e adiacenti al Parco Nazionale di La Maddalena, utilizzando natanti dell'Università o della Base Logistica Operativa Navale del Corpo Forestale di Vigilanza Ambientale della Regione Sardegna nell'ambito dei Progetti INTERREG, "Ambiente Fisico Valorizzazione della fascia Costiera Sardo-Corsa e gestione delle risorse" e "Geologia e Geomorfologia terrestre e marina dell' insieme Corsica-Sardegna e della Toscana e applicazioni". In questo lavoro viene riportata una proposta di mappatura dei sedimenti superficiali alla scala 1:10.000
Recent and historical accumulation of heavy metals and 137Cs in the sediments of Buso basin (Marano lagoon, northern Italy).
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