1,720,966 research outputs found
Using SPMDs to monitor the seawater concentrations of PAHs and PCBs in marine protected areas (Western Mediterranean).
No full textAqueous concentrations of individual polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in coastal sites of two marine protected areas (MPAs), that is, Asinara and the La Maddalena Archipelago, in Sardinia (Western Mediterranean Sea). The use of semi-permeable membrane devices (SPMDs) enabled the detection of dissolved PAHs and PCBs, even in very low concentrations of (pgL-1), in seawater. The results reveal significant differences between the two sampling areas relative to the concentration of the individual PAHs, which provide information concerning the pollution sources affecting relatively pristine environments. The PCBs were generally observed at levels below the detection limits of the utilised method
Passive sampling monitoring of trace metals and organics in seawater in the area of the Costa Concordia disaster (Isola del Giglio, Italy).
No full textThis work presents the results of two years monitoring of organics and trace metals
in seawater with passive sampling techniques in the area around the wreck of the
Costa Concordia cruise ship, which sank off the Mediterranean island of Giglio
(Italy) on January 2012. The aim was to monitor bioavailable contaminants released
by the wreck and/or produced by the removal yard (Parbuckling project). Sampling
was carried out at three sites from May 2012 to September 2014, one month after
the removal of the wreck. Two sites were fixed in the vicinity of wreck, at the bow
and at the aft of the ship; the third one was located in an unexposed beach of the
island. Nine sampling campaigns were carried out. In each station a canister
containing semipermeable membrane devices (SPMDs) and polar organic chemical
integrative samplers (POCIS) was deployed at 10 m. depth, fixed at a buoy by scuba
divers. Furthermore, at each canister, 9 diffusive gradients in thin films (DGTs)
devices were attached. DGTs with three different resins have been used:
Chelex-100 for Cd, Cr, Cu, Ni, and Pb; Fe-oxide for V; Spheron-thiol for Hg.
Deployment time for all samplers ranged from 5 to 7 weeks. Repeatability was
checked by the exposure of triplicate samplers. SPMDs and POCIS were extracted
and analyzed for target compounds by GC/MS. Trace metals accumulated by DGTs
were analyzed after elution by GFAAS. Mercury was determined with a direct
mercury analyzer. SPMDs allowed the determination of dissolved PAHs, NPD,
PCBs, OCPs, and PBDEs. POCIS were used to measure endocrine disruptors, such
as alkylphenols, alkylphenol ethoxylates (APEs), and steroids. The results show
higher concentrations of PAHs in the station near the bow of the ship, all along the
monitoring period. A significant correlation with V measured by DGTs was pointed
out, indicating a contamination by oil, more likely as a result of the yard activities.
This work is part of a larger monitoring plan financially supported by the Italian
Civil Protection
Preliminary data on benthic foraminiferal assemblages and sedimentological characterisation from some polluted and unpolluted coastal areas of Sardinia (Italy)
No full textThe relationship between living benthic foraminiferal faunas and the grain-size distribution of surface sediments was studied in three Sardinian coastal areas: a) the shallow inner shelf between Portoscuso and S. Pietro and the S. Antioco islands; b) the Porto Torres harbour; and c) the La Maddalena Archipelago. This investigation forms part of the research project "EU MOMAR". Benthic foraminifera were identified in 17 samples collected from the three analysed areas. Biotic parameters (Species' Richness, Foraminiferal Density and the Fisher-α index) were calculated to quantify the foraminiferal assemblages within the context of environmental parameters. Grain-size analyses were performed to verify the granulometric nature of the bottom sediments. On the basis of the data obtained, the spatial distribution of the foraminiferal assemblages has allowed highly to less stressed environments to be distinguished and the ecological quality status to be evaluated. The most abundant taxa are Quinqueloculina ungeriana d'Orbigny, 1846, Peneroplis pertusus (Forskal, 1775) and Ammonia tepida (Cushman, 1926) from the Portoscuso samples, P. pertusus, Quinqueloculina seminula (Linnaeus, 1758) and Q. laevigata d'Orbigny, 1839 from the Porto Torres samples and P. pertusus, Bolivina spathulata (Williamson, 1858) and Bolivina striatula Cushman, 1922 from the La Maddalena samples. Among these dominant species, Ammonia tepida and bolivinids appear to show tolerance to environmental disturbance and are therefore particularly suitable as bio-indicators in coastal areas. The sampling sites characterised by better environmental conditions present an epiphytic biocoenosis with Lobatula lobatula (Walker & Jacob, 1798), Planorbulina mediterranensis d'Orbigny, 1826, Elphidium crispum (Linnaeus, 1758) and peneroplids. Correlations are still ongoing between sedimentological features, benthic foraminiferal assemblages and chemical data from these sampled areas, with a view to understanding the environmental anthropogenic impact on coastal systems
Synthesis of a Chemiluminescent Probe Useful for the Purification of Steroid 5alpha-Reductase
No full textSynthesis of 5,6,6-[2H3]- Finasteride and Quantitative determinatin of Finasteride in Human Plasma at Picogram Level by an Isotopic Dilution Mass-Specrometry Method;
No full text19-nor-10-azasteroids, a new class of steroid 5 alpha-reductase inhibitors. 2. X-ray structure, molecular modeling, conformational analysis of 19-nor-10-azasteroids and comparison with 4-azasteroids and 6-azasteroids
No full textEcotoxicological approach for the evaluation of the effects of anthropic impacts in the marine protected area of La Maddalena (Sardinia)
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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