Osservatorio Alto Adriatico

Palmanova, Italy

Osservatorio Alto Adriatico

Palmanova, Italy
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Covelli S.,University of Trieste | Emili A.,University of Trieste | Acquavita A.,Osservatorio Alto Adriatico
E3S Web of Conferences | Year: 2013

Major and trace elements were determined in 14 sediment cores collected from the Marano and Grado Lagoon (northern Adriatic sea). The lagoon is contaminated by several harmful priority substances, heavy metals included, and it has also been declared a "polluted site of national interest" (SIN) mainly due to high Hg concentrations in sediments. Based on a normalization procedure involving predicted linear relationships for "metal vs Al" obtained from the core subsamples, background values for each metal were evaluated on a regional scale and according to the grain-size variability. Compared to Environmental Quality Standards reported in the Italian laws and regulations, the estimated background ranges show that bottom sediments are naturally "enriched" in some metals, such as Cr, Ni and Cd especially in sediments with a high percentage of the fine component. A correct evaluation on sediment quality status should be made on the basis of regional background values for each metal, taking into account local geochemical characteristics, i.e. mineralogical composition and grain-size variability of sediments. © Owned by the authors, published by EDP Sciences, 2013.


Emili A.,University of Trieste | Petranich E.,University of Trieste | Covelli S.,University of Trieste | Acquavita A.,Osservatorio Alto Adriatico
E3S Web of Conferences | Year: 2013

The content of several heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) was determined in sediments and in plants (the halophytes Sarcocornia fruticosa and Limonium vulgare) from two selected saltmarshes located in the Marano and Grado Lagoon (Northern Adriatic Sea). This environment has been affected by severe Hg contamination from both industrial and long-term mining activities. In both saltmarshes, Hg content in sediments exceeded the estimated background value (0.13 μg g-1), showing the highest concentrations (13.7 μg g-1) in the eastern sector (Grado Lagoon), the most affected by cinnabar ore extraction. On the other hand, the saltmarsh, located in the Marano Lagoon, showed a higher degree of contamination for As, Cd and Pb, which can be related to industrial sources. The rhizo-sediments of both halophytes reflected the characteristics of the non-vegetated sediment, with higher organic carbon content and similar metal concentrations. Enrichment Factors (EF=[metal]root/[metal]rhizo-sediment) for each sediment layer were calculated for both halophytes, showing metal enrichments in the roots and the presence of preferential layers of metal accumulation. Hg showed accumulation (EF>1) in the roots below the 20 cm depth, with higher contents in S. Fruticosa. As and Cd were accumulated by both halophytes, more efficiently by S. Fruticosa, and the same species showed also accumulation of Pb and Zn. Translocation of metals from the roots to the aboveground biomass was investigated by measuring metal contents in shoots and leaves of the two species. With the exception of Cd and Hg, all metals were present in the aboveground biomass, most evidently for Cr in S. Fruticosa and Zn in L. Vulgare, although the presence of the latter in leaves could be due to plant physiology rather than translocation of the contaminant. © Owned by the authors, published by EDP Sciences, 2013.


Emili A.,University of Trieste | Carrasco L.,CSIC - Institute of Environmental Assessment And Water Research | Acquavita A.,Osservatorio Alto Adriatico | Covelli S.,University of Trieste
E3S Web of Conferences | Year: 2013

Mercury (Hg) mobility at the sediment-water interface was investigated during a laboratory incubation experiment on highly contaminated sediments (up to 23 μg g-1) of the Gulf of Trieste. Undisturbed sediment was collected in front of the Isonzo River mouth, which inflows Hg-rich suspended material originating from the Idrija (NW Slovenia) mining district. Since hypoxic and anoxic conditions at the bottom are frequently observed, a redox oscillation was simulated in the laboratory at in situ temperature, using a dark flux chamber. Temporal variations of several parameters were monitored simultaneously: dissolved Hg and methylmercury (MeHg), O2, NH4 +, NO3 -+NO2 -, PO4 3-, H2S, dissolved Fe and Mn, dissolved inorganic and organic carbon (DIC and DOC). Benthic fluxes of Hg and MeHg were higher under anoxic conditions while re-oxygenation caused concentrations of MeHg and Hg to rapidly drop, probably due to re-adsorption onto Fe/Mn oxyhydroxides and enhanced demethylation. Hence, during anoxic events, sediments of the Gulf of Trieste may be considered as an important source of dissolved Hg species for the water column. However, re-oxygenation of the bottom compartment mitigates Hg and MeHg release from the sediment, thus acting as a natural "defence" from possible interaction between the metal and the aquatic organisms. © Owned by the authors, published by EDP Sciences, 2013.


Acquavita A.,Osservatorio Alto Adriatico | Acquavita A.,University of Trieste | Covelli S.,University of Trieste | Emili A.,University of Trieste | And 7 more authors.
Estuarine, Coastal and Shelf Science | Year: 2012

The existence of mining tailings in Idrija (Slovenia) and their subsequent transportation via the Isonzo River has been the primary source of mercury (Hg) in the northern Adriatic Sea for almost 500 years, making the Gulf of Trieste and the adjacent Marano and Grado Lagoon two of the most contaminated marine areas in the world. A further, more recent, contribution of Hg has been added by the operation of a chlor-alkali plant (CAP) located in the drainage basin flowing into the Lagoon. On the basis of previous research, as well as new data obtained from the "MIRACLE" project (Mercury Interdisciplinary Research for Appropriate Clam farming in a Lagoon Environment), the spatial distribution of Hg and its relationships with methylmercury (MeHg), organic matter and several geochemical parameters in surface sediments were investigated. The predominant and long-term impacts of the cinnabar-rich Isonzo River particulate matter in the Lagoon surface sediments are evident and confirmed by a decreasing concentration gradient from east (>11μgg -1) to west (0.7μgg -1). Hg originated from the CAP is only significant in the central sector of the Lagoon. Hg is primarily associated with fine-grained sediments (<16μm), as a consequence of transport and dispersion from the fluvial source through littoral and tidal currents. However, speciation analyses highlighted the presence of Hg sulphides in the coarse sandy fraction of sediments from the eastern area, as expected given the origin of the sedimentary material. Unlike Hg, the distribution of MeHg (0.47-7.85ngg -1) does not show a clear trend. MeHg constitutes, on average, 0.08% of total Hg and percentages are comparable to those obtained in similar lagoon environments. Higher MeHg concentrations in low to intermediate Hg-contaminated sediments indicate that the metal availability is not a limiting factor for MeHg occurrence, thus suggesting a major role played by environmental conditions and/or speciation. The reasonably good correlation between MeHg normalized to humic acid (HA) content and humic δ 13C indicates that MeHg is preferentially associated with autochthonous δ 13C-enriched HAs in lagoon surface sediments, suggesting that the structure of "marine" HAs, less refractory and less aromatic, could favor MeHg binding and/or production. In the context of the potential hazard of Hg and MeHg accumulation in reared clams, the choice of a site for the extension of farming activities inside the Marano and Grado Lagoon is dependent on several factors and cannot be decided solely on the basis of the total Hg content in the sediment. © 2012 Elsevier Ltd.


Acquavita A.,Osservatorio Alto Adriatico | Mattassi G.,Osservatorio Alto Adriatico | Rossin P.,Osservatorio Alto Adriatico | Tamberlich F.,Osservatorio Alto Adriatico
Water, Air, and Soil Pollution | Year: 2010

A set of ten heavy metals (Al, As, Cd, Cr, Cu, Hg, Ni, Pb, V, and Zn) was investigated in surface sediments (0-5 cm) collected in 21 sites of the Gulf of Trieste, Northern Adriatic Sea (Italy). The aim of this work was to obtain a preliminary assessment about the levels and spatial distribution of these selected elements. Ancillary parameters such as grain size, total organic carbon, and total nitrogen were also determined. The enrichment factor was calculated to discriminate if a natural condition or a status of anthropogenic contamination occurs. In addition, a set of sediment quality guidelines, mean effect low range and effect medium range quotients, was also applied in order to predict the probability of adverse biological effects on the benthic community. © 2009 Springer Science+Business Media B.V.


Acquavita A.,Osservatorio Alto Adriatico | Capriglia L.,Sezione Operativa Laboratorio Chimico
Water, Air, and Soil Pollution | Year: 2010

In order to find out a new effective accumulator of polycyclic aromatic hydrocarbons (PAHs) useful for monitoring studies on a large scale and low costs, the accumulation capacity of both biological and artificial matrixes (mosses and polyester fibers, respectively) has been tested. For this purposes, Hypnum cupressiforme and dacron® were exposed to pollution airborne in two sites located nearby an active iron industry and in center of the town of Trieste, where high PAH pollution spots, due to vehicular traffic, are usually detected. The samplers were exposed in six sampling sessions for 21 days. The results obtained were compared with data collected by active PAH samplers, usually employed for official widespread monitoring. The level of correlation between the data sets was calculated. Furthermore, a repeatability study of data was performed. According to the results, both matrixes are good PAH accumulators, though they show different skills. © 2009 Springer Science+Business Media B.V.


Acquavita A.,University of Trieste | Emili A.,University of Trieste | Covelli S.,University of Trieste | Faganeli J.,Slovenian National Institute of Biology | And 4 more authors.
Estuarine, Coastal and Shelf Science | Year: 2012

Sediments of the Marano and Grado Lagoon (Adriatic Sea, Italy) represent one of the world's most major repositories of mercury (Hg). Its presence is a direct consequence of the historical mining activity in nearby Idrjia (Slovenia), as well as significant discharges from a chlor-alkali plant into the Aussa-Corno river system, which connects to the lagoon. Previous studies have shown that sediment acts as secondary source of Hg species to the overlying water column in natural conditions. However, evidence for the effects of resuspension on the dynamics of Hg species is still lacking. The work reported in this paper formed part of the multidisciplinary "MIRACLE" project, aimed at identifying areas at low risk of Hg bioaccumulation in commercial Manila Clams, an important part of the local economy in this region. The effect of resuspension on the cycling of inorganic mercury (IHg), reactive mercury (RHg) and methylmercury (MeHg) between the sediment and water column was investigated in a mesocosm study. Two experiments were conducted in October 2009 and September 2010 based on material collected from sites heavily impacted by Hg and periodically subjected to dredging activities. Designed to mimic the resuspension of particles, both experiments revealed that the release of Hg species from the solid to the dissolved phase became negligible quickly after the event. MeHg values did not change according to total mercury (THg), suggesting that the enhancement of methylation processes may occur. The findings reported in this paper may be useful for the local management of dredging and fishing activities, although mass balance calculations showed that the total flux of Hg species are trivial compared to lagoon-wide processes. © 2011 Elsevier Ltd.


Monti M.,National Institute of Oceanography and Applied Geophysics - OGS | Minocci M.,National Institute of Oceanography and Applied Geophysics - OGS | Milani L.,Osservatorio Alto Adriatico | Fonda Umani S.,University of Trieste
Estuarine, Coastal and Shelf Science | Year: 2012

Abundance and composition of microzooplankton were studied over a 15 years period (from March 1986 to December 1990 and from July 1998 to December 2010) in the Gulf of Trieste (Adriatic Sea, NE Mediterranean Sea). Sampling was conducted biweekly-monthly at the surface at the historical station C1, 200 m offshore (bottom depth 17.5 m). Aloricate ciliates dominated in both periods (median 117 and 243 ind. L-1 in the first and second period respectively) while tintinnids were more abundant in the first period (median 55 ind. L-1vs 16 ind. L-1). For heterotrophic dinoflagellates there are no data during the first period and in the second one they represented the second major group. Micrometazoans remained almost constant over time. In the first period all microzooplankton groups showed a maximum in April, while in the last period the peak has shifted to September. This is particularly evident for both aloricate ciliates and micrometazoans. Tintinnids, that in the past had the absolute maximum in spring, in the second period maintained the only, lower peak in October. Tintinnids in the first period were constituted by 27 species and dominated by the genera Tintinnopsis, Stenosemella and Salpingella. In the last 10 years we registered a dramatic decrease in abundance, paralleling an increase in species (40) with some " new entries" as well as the almost complete disappearance of genera Helicostomella, Favella, Coxiella and Steenstrupiella. The observed changes of the seasonal dynamics of microzooplankton abundance, as well as of the tintinnids composition over the long period considered in our study, might suggest a climatic forcing together with the known anthropogenic oligotrophication of the entire North Adriatic. © 2012 Elsevier Ltd.


Fontolan G.,University of Trieste | Pillon S.,University of Trieste | Bezzi A.,University of Trieste | Villalta R.,Autorita di Bacino Regionale ABR FVG | And 3 more authors.
Estuarine, Coastal and Shelf Science | Year: 2012

Historical transformations of the saltmarshes in the six sub-basins of the Marano and Grado Lagoon were analyzed using aerial photographs (1954, 1990, 2006), and the support of historical maps and topographic surveys. Analysis of the 2006 set of aerial photographs enabled the definition of the present extent and distribution of the saltmarshes inside the lagoon (760 ha), with a total reduction in saltmarsh area of 16% (144 ha) compared to 1954. Direct human actions played a significant role in the budget, since total loss due to land reclamation and dredging during this period amounted to 126 ha. After excluding the total loss due to direct human interventions, different erosional and depositional marsh types were recognized and associated with different forcing factors, based on morphological and geographical evidence. Over the 52-year period marshes were lost due to: (a) drowning - the combined effects of eustatism, regional subsidence and autocompaction (102 ha); (b) edge-retreat by wind wave attack (34 ha); (c) erosion by vessel-generated waves (37 ha); and (d) coastal dynamics and inlet migration (5.7 ha). Conversely, marshes gained in area due to: (a) fluvial input (63 ha); (b) tidal input (27 ha); (c) paralagoonal deposition (45 ha); (d) the re-opening of abandoned fish farms (18 ha); and (e) the dumping of dredged material (8 ha). Our analysis demonstrates that local and short-term forcing factors can obliterate or compensate the long-term ones, especially the relative sea-level rise. A test of the integrated sediment budget carried out on one third of the total lagoon, through a bathymetric comparison between datasets from 1964 to 2009, pointed out that conservation or slight expansion of the marshes inside these basins were linked to an overall positive sediment budget of 61,000 m 3/y. Nevertheless, significant morphological changes occurred in the submerged basin, which is affected by sustained deposition along the inner margins due to sediment supplies, by an overall erosion of tidal and sub-tidal flats far from the tributaries, and by an important infilling of the channels. The analyzed data, along with information available for the Venice Lagoon, highlights how the fate of open-water lagoons is to flatten whilst submerging because of the strong influence of wind waves, which tend to transform the lagoon into a marine embayment. This transgressive condition reduces, if not negates, the compensative effect of the sedimentation rate on wind-wave-induced shear stress excess, since supplies seem to contribute primarily to the morphological accommodation. © 2012 Elsevier Ltd.


Bettoso N.,Osservatorio Alto Adriatico | Acquavita A.,Osservatorio Alto Adriatico | D'Aietti A.,Osservatorio Alto Adriatico | Mattassi G.,Osservatorio Alto Adriatico
Annales, Series Historia Naturalis | Year: 2013

The Marano and Grado Lagoon is one of the best preserved wetlands in the whole Mediterranean area. In spite of the presence of chemical pollutants, especially mercury, no clear criticism of the ecological status for macrozoobenthos and fish fauna was found. The distribution of macrozoobenthos species shows a clear relationship with the salinity gradient, due to both the renewal time of seawater and the freshwater inputs from the inland. The Lagoon constitutes an important habitat for fish fauna, particularly for the sensitive species, and a nursery ground for juveniles of marine migrants especially in the inner area of Marano basin. After 25 years from the introduction of Manila clam (Venerupis philippinarum), the pathway toward its sustainable aquaculture seems now possible. © 2013, University of Primorska. All rights reserved.

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