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The concentration and particle-size distribution of ionic species in Antarctic aerosol samples were determined to investigate their potential sources, chemical evolution, and transport. We analyzed aerosol samples collected at two different Antarctic sites: a coastal site near Victoria Land close to the Italian Research Base 'Mario Zucchelli', and another site located on the Antarctic plateau, close to Italian-French Concordia Research Station. We investigated anionic compounds using ion-chromatography coupled to mass spectrometry, and cationic species through capillary ion chromatography with conductometry. Aerosol collected close to the coast was mainly characterized by sea salt species such as Na, Mg, and SO . These species represented a percentage of 88% of the total sum of all detected ionic species in the aerosol samples from the coastal site. These species were mainly distributed in the coarse fraction, confirming the presence of primary aerosol near the ocean source. Aerosol collected over the Antarctic plateau was characterized by high acidity, with nss-SO , NO , and methanesulfonic acid as the most abundant species. These species were mainly distributed in the <0.49 μm fraction, and they had a behavior of a typical secondary aerosol, where several chemical and physical processes occurred. [ABSTRACT FROM AUTHOR]

Harbours are important hubs for economic growth in both tourism and commercial activities. They are also an environmental burden being a source of atmospheric pollution often localized near cities and industrial complexes. The aim of this study is to quantify the relative contribution of maritime traffic and harbour activities to atmospheric pollutant concentration in the Venice lagoon. The impact of ship traffic was quantified on various pollutants that are not directly included in the current European legislation for shipping emission reduction: (i) gaseous and particulate PAHs; (ii) metals in PM; and (iii) PM and PM. All contributions were correlated with the tonnage of ships during the sampling periods and results were used to evaluate the impact of the European Directive 2005/33/EC on air quality in Venice comparing measurements taken before and after the application of the Directive (year 2010). The outcomes suggest that legislation on ship traffic, which focused on the issue of the emissions of sulphur oxides, could be an efficient method also to reduce the impact of shipping on primary particulate matter concentration; on the other hand, we did not observe a significant reduction in the contribution of ship traffic and harbour activities to particulate PAHs and metals. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The concentrations of 19 elements in wild and genetically modifiedNicotiana langsdorffii(N. langsdorffii) exposed to Chromium (VI) and to water deficit were determined and compared to provide new information about their response to abiotic stress. Genetic modifications by GR and RolC genes (encoding for the ratglucocorticoid receptorand forAgrobacterium rhizogenesRolC, respectively) were investigated because they induce significant, but only partially known changes in the plant response to stress. Simultaneous determination of Al, As, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Na, Pb, Rb, Sr, V and Zn was carried out by ICP-MS equipped with a collision/reaction cell (ICP-ORS-MS). The methodology was optimised by testing the grinding, homogenisation, digestion and analysis procedures, to reduce the uncertainty of the experimental results and to identify statistically significant differences between nine sample pools, for a total of 75 samples. The quality control procedure was carried out by blank control and by evaluating the detection limits and repeatability. Trueness was assessed by analysing certified reference material, NIST 1573a. Significant differences were observed in the uptake and accumulation of several elements in the wild-typeN. langsdorffiisamples, either with respect to the plants submitted to water deficit and exposure to Cr(VI) or with respect to the genetically modified plants. The differences were highlighted by principal component analysis (PCA). The analysis of the element content of the whole plant, combined with the data found in the literature, allows us to hypothesise effects on the metabolic mechanism controlling the uptake and translocation of elements inside the vegetal organism. Because genetic and chemical stress decreases the nutrient concentration in the whole plant, we can say that the uptake at root level is affected. The increase in concentration of elements such as As, Sr and Al indicates a decreased selectivity in the uptake of potentially toxic elements and, consequently, highlights the effects on the plant’s metabolic processes. [ABSTRACT FROM AUTHOR]

The results of an experimental analysis carried out to investigate PM2.5 concentration levels and the content of polycyclic aromatic hydrocarbons, as well as inorganic trace elements in the atmospheric particles are presented. Measurements were taken with a micrometeorological station equipped with an optical PM2.5 detector, and simultaneously, particles were collected on filters for subsequent chemical analyses. The average value of daily PM2.5 concentration is 21.5 ug/m3 and real-time measurements indicate that the average concentration during the day (8 am to 8 pm) is about 25% lower than the nocturnal average. Short-time averages of PM2.5 decrease when the wind speed increases as consequence of the more efficient mixing. Meteorological measurements indicate the presence of a local daily (breeze) circulation with wind blowing from the Alps or the Adriatic Sea and, during this circulation, larger concentrations were observed, with wind coming from the Alps. Days of high PM2.5 concentration with dominant anthropic or with prevalent crustal contributions were identified. Regarding trace metals, their average concentrations are comparable to those found in others urban areas, except for Cd (3 ng m-3), probably due to the presence of glass- works in Murano. The highest concentrations are observed for K (99 ng m-3) and Na (73 ng m-3), which are the main constituents of marine spray, while the lowest concentrations are observed for elements such as Cs and Co (respectively 0.01 and 0.02 ng m-3). Also the concentrations of PAH are comparable with those of other industrial areas, as their sum ranges from 0.16 ng m-3 to 3.73 ng m-3, but if considered as B(a)P toxicity equivalent, they are largely lower (0.036±0.026 ng m-3). From the analyses of discriminating ratios, it has been found that the main origin of PAH in PM2.5 samples may be petrogenic, probably related to the presence of refinery and petrochemical plants on the mainland, although the contribution of combustion processes cannot be excluded. [ABSTRACT FROM AUTHOR]

The methodology for using DPASV to study cadmium complexation in seawater is evaluated using EDTA as a model ligand and by analysing natural samples. The results show that the methodology gives an accurate evaluation of metal complexation when inert complexes are studied, both as regards the ligand concentration and the conditional stability constant; the error for both the parameters is lower than 10% at a ligand concentration of about 10(-8) M and a conditional stability constant of 10(9) M-1. Cadmium complexes with ligands present in natural seawater show an evident kinetic lability that may lead to underestimation of the conditional stability constant when a working electrode characterised by a very thick diffusion layer is used. The conditional stability constant in one water sample of the Adriatic coast ranged between 0.14 and 1.4 l/nmol using a rotating disk electrode at rotation rates of 300 and 6000 rpm. The results of cadmium complexation obtained for samples collected in coastal seawater show that the ligands present low specificity for the metal.