To methylate or not to methylate? Study of Mercury Speciation along\ud the Venetian Littoral System (Q-ALiVe project)

The biogeochemical cycle of mercury (Hg) is affected not only by the physical, chemical and hydrological characteristics of the environment, but also by changes in productivity and biodiversity. In waters the complexes of Hg are related to the salinity and to the load of dissolved organic carbon (DOC) in the dissolved and in the particulate phases. Surface and bottom seawater were sampled along the Venetian coast at ten sites with different characteristics. Samples were analyzed employing hyphenated techniques and LOD (limit of detection) and LOQ (limit of quantification) were quantified. Although for some samples both the species were under the LOQ, the presence of methyl mercury (CH3Hg+) and ionic mercury (Hg2+) at the same time in surface and in bottom waters were observed. Variability in CH3Hg+ concentrations may be due to changes in the phytoplankton communities, which in turn may be affected by nutrient loads from the catchment area and port mouths of the Venice Lagoon. Thus, monitoring these nutrient loads may be essential for the health of the Venetian littoral system, since they may affect blooms, methylation and hyper-bioaccumulation along the trophic web, with effects on the environment and on human health

Microplastic accumulation in benthic invertebrates in Terra Nova Bay (Ross Sea, Antarctica)

Microplastic contamination of the benthic invertebrate fauna in Terra Nova Bay (Ross Sea, Antarctica) was determined. Twelve macrobenthic species, characterized by different feeding strategies, were selected at 3 sampling sites at increasing distance from the Italian Scientific Base (Mario Zucchelli, Camp Icarus, Adelie Cove). The 83% of the analyzed macrobenthic species contained microplastics (0.01–3.29 items mg−1). The size of the particles, measured by Feret diameter, ranged from 33 to 1000 µm with the highest relative abundance between 50 and 100 µm. Filter-feeders and grazers displayed values of microplastic contamination from 3 to 5 times higher than omnivores and predators, leading to the hypothesis that there is no evident bioaccumulation through the food web. The prevalent polymers identified by micro-FTIR were nylon (86%) and polyethylene (5%); other polymers identified in Antarctic benthos were polytetrafluoroethylene, polyoxymethylene, phenolic resin, polypropylene, polystyrene resin and XT polymer

To methylate or not to methylate? Study of Mercury Speciation along the Venetian Littoral System (Q-ALiVe project)

The biogeochemical cycle of mercury (Hg) is affected not only by the physical, chemical and hydrological characteristics of the environment, but also by changes in productivity and biodiversity. In waters the complexes of Hg are related to the salinity and to the load of dissolved organic carbon (DOC) in the dissolved and in the particulate phases. Surface and bottom seawater were sampled along the Venetian coast at ten sites with different characteristics. Samples were analyzed employing hyphenated techniques and LOD (limit of detection) and LOQ (limit of quantification) were quantified. Although for some samples both the species were under the LOQ, the presence of methyl mercury (CH3Hg+) and ionic mercury (Hg2+) at the same time in surface and in bottom waters were observed. Variability in CH3Hg+ concentrations may be due to changes in the phytoplankton communities, which in turn may be affected by nutrient loads from the catchment area and port mouths of the Venice Lagoon. Thus, monitoring these nutrient loads may be essential for the health of the Venetian littoral system, since they may affect blooms, methylation and hyper-bioaccumulation along the trophic web, with effects on the environment and on human health

Persistent Organic Pollutant in the Venetian coastal environment

The Venetian coastal area is characterized by a strong anthropogenic impact and its quality is very important because of local economical activities, such as tourism or fishing. In the context of the Water Framework Directive (WFD, 2000/60/EC), the aim of the project Q-ALiVe (Qualità dell’Ambiente Litoraneo Veneto) is to check the environmental quality of the Venetian coastal area and whether rivers contamination could influence it. We studied an area going from the mouth of the Adige river to the Malamocco inlet of the Venice lagoon (including the mouth of the Brenta river and the Chioggia lagoon inlet), to distance from the coast of up to about a kilometer. In this work we presented the data relative to Persistent Organic Pollutants (POPs) as PCBs, PBDEs and PAHs, in samples of seawater. Samples were collected during four different sampling campaigns, in different seasons (June 2011, August 2011, September 2011, November 2011); in each sampling campaign we collected 10 samples of surface water. Analytical samples procedures for POPs include liquid-liquid continuous extraction, followed by an automated purification step, with neutral silica columns. Analysis were made by HRGC-HRMS (PCBs) or HRGC-LRMS (PAHs and PBDEs). Quantification was made by isotope dilution. Results suggest a negligible influence of rivers contamination to the quality of the sea facing the city of Chioggia and the Venice lagoon. Funds for this work were provided, in the framework of Q-ALiVe Project, by the Regione del Veneto - L.R. 15/07

Development of “Sediment washing” by natural organicsubstances of dredged sediments of the Venice Lagoon, Italy.

The contamination of sediments in coastal areas and harbours is due to a wide range of organic pollutants and trace elements; in these areas sediments may be a significant sink and/or source of these pollutants. Remediation and environmental recovery of sediments are extremely important in harbour areas, considered the need to dredge sediments in order to keep channels of navigation open. The main goal of this project is to assess a novel washing procedure for dredged sediments, that is environment friendly and suitable for the variety of pollutants, by exploiting the surface-active and complexing properties of natural organic substances. Dredged sediments from the industrial area of the Venice lagoon were analysed to evaluate the concentrations of POPs and the total concentrations of several trace elements (such as Cr, Zn, Cd, As, Hg, etc.). Furthermore, we used a modified sequential extraction procedure in order to evaluate the concentration of the chemical fractions: the exchangeable, the carbonate bound, the Fe and Mn oxides bound, the sulphur and organic matter bound, the residual bound. In the second phase of this study, the washing process was assessed; different parameters were considered (such as pH, sediments/ washing solution volume ratio, length of washing, etc.). All the batch experiments were run in duplicate, to test the homogeneity and the repeatability of the procedure, by using commercially available natural organic substances (Sigma). After being washed, sediments showed an average decrease in the concentrations of organic and inorganic pollutants (40% and 30% respectively), These results are very promising, due to the holistic approach used for the different classes of pollutants. This study underlines the importance of speciation, since, according to the most recent frameworks on risk assessment, it is essential to know the bioavailability and bioaccessibility of pollutants in order to plan the most suitable remediation project

Removal of Cu from aqueous solutions by synthetic hydroxyapatite: EXAFS examination

The sorption of aqueous Cu on synthetic hydroxyapatite has been investigated by means of the results of a combined structural simulation and extended X-ray absorption fine structure (EXAFS) analysis. The removal of Cu was studied in batch experiments at 25±2 ◦C. The sorption of Cu follows Langmuir behaviour and was attributed to a two-step mechanism involving surface complexation and ion exchange with Ca resulting in the formation of a copper-containing hydroxyapatite. EXAFS results suggest that the heavy metal is present in the Cu2+ form. The structural experimental and theoretical analysis shows that Cu is bond to about four O atoms at a distance of about 1.95 A° . In all the studied cases the immobilization site of Cu is the same. The fixation of Cu occurs in the surface sites of hydroxyapatite whereas the sorption in the Ca sites in the inner part of the structure is unlikely

Studio della speciazione dello zinco nella Laguna di Venezia tramite Voltammetria di Ridissoluzione Catodica

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