Nitrogen Budget in a Lowland Coastal Area Within the Po River Basin (Northern Italy): Multiple Evidences of Equilibrium Between Sources and Internal Sinks

Detailed studies on pollutants genesis, path and transformation are needed in agricultural catchments facing coastal areas. Here, loss of nutrients should be minimized in order to protect valuable aquatic ecosystems from eutrophication phenomena. A soil system N budget was calculated for a lowland coastal area, the Po di Volano basin (Po River Delta, Northern Italy), characterized by extremely flat topography and fine soil texture and bordering a network of lagoon ecosystems. Main features of this area are the scarce relevance of livestock farming, the intense agriculture, mainly sustained by chemical fertilizers, and the developed network of artificial canals with long water residence time. Average nitrogen input exceeds output terms by ~60 kg N ha^?1 year^?1, a relatively small amount if compared to sub-basins of the same hydrological system. Analysis of dissolved inorganic nitrogen in groundwater suggests limited vertical loss and no accumulation of this element, while a nitrogen mass balance in surface waters indicates a net and significant removal within the watershed. Our data provide multiple evidences of efficient control of the nitrogen excess in this geographical area and we speculate that denitrification in soil and in the secondary drainage system performs this ecosystemic function. Additionally, the significant difference between nitrogen input and nitrogen output loads associated to the irrigation system, which is fed by the N-rich Po River, suggests that this basin metabolizes part of the nitrogen excess produced upstream. The traditionally absent livestock farming practices and consequent low use of manure as fertilizer pose the risk of excess soil mineralization and progressive loss of denitrification capacity in this area.     

OH-initiated oxidation of DMS/DMSO: reaction products at high NOx levels

Dimethylsulphide (DMS) gas phase oxidation with OH radicals was investigated by long path FT-IR spectroscopy and by ion chromatography (IC) and HPLC-MS2 to quantify the reaction products and evaluate heterogeneous processes. The experiments were performed considering two different NOx (NO2+NO) levels. The initial concentration of NO2 was varied from 24 ppbV (NOx=1 ppmV) to 953 ppbV (NOx=10 ppmV). Photolysis of H2O2 was used as the OH-radical source. SO2, dimethylsulphoxide (DMSO), dimethylsulphone (DMSO2), methanesulphonic acid (MSA), methanesulphinic acid (MSIA) and methane sulphonyl peroxynitrate (MSPN) were identified as the main sulphur-containing products. The results indicate that higher NOx levels play a significant role in the chemistry of CH3S(O)x radical, influencing both the SO2/MSPN ratio and the amount of the sulphur species in the condensed phase, and that the NO2/NO ratio could influence the trends in the molar yields of the different products. For this reason the NOx content results a limiting parameter when on measure DMS in atmospheric environment.     

Multivariate characterisation of the habitats of seven species of Malayan mudskippers (Gobiidae: Oxudercinae)

Mudskippers (Gobiidae: Oxudercinae) are amphibious gobies. The occurrence and habitats of seven sympatric species of Malayan mudskippers were recorded: Boleophthalmus boddarti, Boleophthalmus pectinirostris, Periophthalmodon schlosseri, Periophthalmus chrysospilos, Periophthalmus gracilis, Periophthalmus variabilis and Scartelaos histophorus. A total of 14 surveys were made at six localities along 120 km of the west coast of the Malay Peninsula in August 1996 and September 2006. A multivariate set of ordinal parameters were used to measure the quantity of environmental water in mudskippers’ habitats, and three guilds of species were discriminated. The resulting pattern mirrored the adaptive scenario depicted by physiological and anatomical studies of mudskippers’ terrestriality, although in one case a terminal taxon was less terrestrial than other more basal ones. Differentiation of trophic niches may also play a role in habitat selection by the herbivorous Boleophthalmus spp., which were only found in unvegetated, illuminated areas and on wet mud at low tide. With the more terrestrial guild, a significant negative co-occurrence suggested direct interspecific competition. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A study of land transport of dangerous substances in Eastern Sicily

In this work a quantitative analysis of the risk in the land transport of hazardous materials in Sicily has been executed. Risk calculation has been carried out using the TRAT-GIS code, a software for incidental and environmental risk assessment associated with the transport of dangerous substances and supported by a Geographical Information System (GIS). Results have been collected in a database, the GIS allows to display the risk maps.Risk analysis has been made on a regional scale, then some critical points have been analysed in detail. Comparisons between different typologies of transport and routes have been possible by means of the risk maps. In order to reduce the risk and improve the protection of citizens, some proposals have been analysed in these past years and some of them have been recently realized. In this study other proposals for the optimization of the transport system have been formulated, results have also permitted to evaluate the risk reduction after the future application of the Regional Transportation Plan for the Sicily.     

Emission of air pollutants from burning candles with different composition in indoor environments

Candle composition is expected to influence the air pollutants emissions, possibly leading to important differences in the emissions of volatile organic compounds and polycyclic aromatic hydrocarbons. In this regard, the purity of the raw materials and additives used can play a key role. Consequently, in this work emission factors for some polycyclic aromatic hydrocarbons, aromatic species, short-chain aldehydes and particulate matter have been determined for container candles constituted by different paraffin waxes burning in a test chamber. It has been found that wax quality strongly influences the air pollutant emissions. These results could be used, at least at a first glance, to foresee the expected pollutant concentration in a given indoor environment with respect to health safety standards, while the test chamber used for performing the reported results could be useful to estimate the emission factors of any other candle in an easy-to-build standardised environment.     

Classification and distribution of freshwater microplastics along the Italian Po river by hyperspectral imaging

Environmental Science and Pollution Research - In this work, freshwater microplastic samples collected from four different stations along the Italian Po river were characterized in terms of...