1,720,997 research outputs found
Distribution and contamination assestment of heavy metals in sediment of the port of Bari - Italy
No full textEsterification, transesterification and hydrogenation reactions of polyunsaturated compounds catalyzed by a recyclable polymer supported palladium catalyst
No full textAliphatic and aromatic carboxylic acids were converted into their corresponding esters using a polymer supported palladium(II) β-ketoesterate complex under hydrogen atmosphere in the presence of catalytic bromobenzene in alcohols. This method was also applicable to the transesterification of esters. Good to excellent yields were obtained for different aliphatic or aromatic starting materials. The esterification (or transesterification) was promoted by the in situ generation of HBr from bromobenzene, which provided a mild acidic reaction environment. Pd(II) centers were converted into polymer stabilized metal nanoparticles (the true active species) under reaction conditions. The palladium catalyst exhibited a remarkable activity and was reusable for eight consecutive cycles. The present system was also tested for the preparation of partially hydrogenated fatty acid methyl esters, starting from a mixture composed by highly polyunsaturated esters and free carboxylic acids, taken as a model acidic feedstock for biodiesel upgrading
Mobility of trace elements in a coastal contaminated site under groundwater salinization dynamics
Full text link: Water pollution is a significant issue resulting from past long-term actions. The remediation projects carried out under law constraints for industrial plants, which have been the major contributors to environmental and water pollution, are currently providing a significant amount of data about contaminated soil, surface waters, and groundwater. Most of such plants worldwide are in coastal zones. Based on a significant amount of chemical and environmental data for a coastal contaminated site subject to variable groundwater salinization, this study aimed to understand the mobility of some trace elements because of coastal zone dynamics. Data concerned 688 groundwater samples, including As, Hg, Cd, Crtot, Cu, Ni, Pb, V, Se, Zn, pH, electrical conductivity, chlorides, total organic carbon and organic contaminants as quantitative variables, enhanced by additional qualitative variables such as groundwater salinity, season, water level, precipitation, and industrial activity type to make the dataset as representative as possible of the site under investigation. The study used robust multivariate statistical analyses to analyse the complex dataset and explain the relevant factors influencing contaminant behaviour under different environmental conditions. The Multivariate Statistical Analysis distinguished three clusters of trace elements with diverse reactivity to changes in groundwater salinization. The first includes Se, Cu, Crtot, V, and Ni, showing the highest correlation with electrical conductivity and chlorides because of their high affinity to form chloride or organic chloride complexes and for ion competition. Zn and Pb cluster in the second group: they are less reactive to groundwater salinization and more influenced by cation and anion competition and organic matter. The mobility of Hg and As (third cluster) significantly correlates with Fe and Mn, underlining the dominant role of reductive dissolution of trace elements-bearing minerals (Fe/Mn/Al-oxy-hydroxides) and metal-organic complexes. The correlation between the clustering of variables in groundwater and soils shows the influence of sediment structure, mineral composition, and physical and chemical soil conditions on the distribution in soils of trace elements and their transport to groundwater. The study proposes a valuable approach for assessing the effects of salinization in contaminated coastal aquifers. It supports planning multi-purpose characterization and monitoring campaigns of contaminated coastal sites and provides guidance on the correct associated remediation projects
Multivariate analyses for investigating highly polluted marine ecosystem: The case study of Mar Piccolo (Taranto, South Italy)
No full textThis study presents the benefits of the application of multivariate techniques for the hazard assessment of a heavily polluted marine ecosystem. The study area, named Mar Piccolo, near Taranto city (Southern Italy), is a shallow marine basin located nearby an industrial compromised area, declared by the national government as Contaminated Site of Environmental Interest (SIN) due to the presence of long-lasting large industrial settlements that have severely impacted the marine environment. Besides the anthropogenic pressures, the marine basin is characterized by high productivity of several species at different trophic levels of the food chain, that confers to the bottom sediments an unusually high organic matter content. The latter is even enhanced by the presence of freshwater springs in the marine basin. The dynamism of the ecosystem demands for advanced evaluation tools for its correct characterisation. Multivariate ANOVA allied by Hierarchical Clustering are applied in this research to provide a readable picture of the quality status of the sediments, aiming at identifying different loading factors and getting insights into their simultaneous effects. The innovative approach adopted circumvents inefficient time-consuming procedures, usually required by the conventional univariate analyses of each parameter selected for sediment characterisation. A comprehensive hazard assessment was possible thanks to a clear graphical representation of the hazard distribution that supported the identification of the hazard controlling factors, confirming the efficiency of the adopted approach. The tools proposed herein can thus be recommended for the decision makers in investigating and interpretation of the quality status of complex polluted marine eco-systems
Enhancing the performance of hazard indexes in assessing hot spots of harbour areas by considering hydrodynamic parameters
No full textThe hazard assessment strategies for harbour areas usually rely on tools able to predict environmental threats posed by contaminated sediments, mostly based on biological and chemical parameters and distinctly less on hydrological factors. Although ports are considered semi-enclosed and low-energy systems with scarce capacity to disperse contaminants to the open sea, the hydrological pattern established within the port basin cannot be neglected, especially when the localisation of hot spots is required for clean-up and remediation actions. In the present study we considered both approaches (biological/chemical and hydrological) for assessing hot spots of harbour areas. In particular, the relationship between the sediment hazard assessment c_NWAC (cumulative Normalized and Weighted Average Concentration) index (which is based on chemical and biological data) and a properly selected hydrodynamic parameter (the bottom shear stress) of the port area was investigated. This study demonstrates that marine currents influence significantly the fine-grained fraction distribution of the surficial sediments, and thus, the spatial and temporal variability of contaminant concentration. The evaluation of hydrodynamic parameters enhances the performance of hazard tools in the localization of areas of most concern and thus a detailed knowledge of the hydrodynamic features of the port seabed is advisable before defining a proper characterisation strategy for the harbour area
Green Intermodal Freight Transport (GIFT) Project: Analysis and results
No full textThe concept of transport corridors is marked by a concentration of freight traffic
between major hubs and by relatively long distances of transport. Green transport corridors
will reflect an integrated transport concept where short sea shipping, rail, inland waterways
and road complement each other to enable the choice of environmentally friendly transport.
The main aim of Green Intermodal Freight Transport (GIFT) project is to map, analyze, and
evaluate the status of the transport sector in the selected transport network and propose new
policies and strategies in infrastructure, processes, assets, Information and Communication
Technologies, legislation, norms and harmonization/standardization issues, in order to
promote innovative green intermodal freight transport corridors.
The purpose of this paper is to present the central activities of the project, and the expected/
achieved results and outputs
Long-term monitoring programs to assess environmental pressures on coastal area: Weighted indexes and statistical elaboration as handy tools for decision-makers
Full text linkData generated by long-term monitoring programs for coastal areas are intricate and require advanced tools able to identify the factors, natural or anthropogenic, responsible for the observed quality status. In the present study, data stemming from a 5-year monitoring programme of the Apulian coast were utilized for validating a speedy and comprehensive approach to assess the environmental quality of the marine-coastal area. Selecting 12 indicator contaminants controlling the pollution degree of the bottom sediments and attributing to each of them a weighted relevance according to their hazard potential, two multimetric indexes were calculated, helping to establish how and to what extent the selected contaminants could affect the achievement of good chemical and ecological status of coastal area. The relationships between calculated hazard degree values and the main natural factors loading on the study area were addressed through multivariate analyses. The variability of hazard degree values over time was explained by means of combined use of multivariate analyses and multimetric indexes, affording a handy method that allows to differentiate the role of natural factors, such as hydrodynamic and morphological features of the coastal track versus that of anthropogenic pressures. The combined approach adopted supports a reliable hazard assessment at long-term period and at a large spatial scale
Iron Oxides on Waste Steel Slags as Catalyst for the Transfer Hydrogenation of Nitrobenzene Using iso‐Propanol as Hydrogen Source
No full textIron oxide-based catalysts have been widely investigated due to their high catalytic activity and operational availability. However, in the perspective of commercial application, performance and cost are two crucial parameters for the development of catalysts. To reduce the cost, it is possible to use industrial wastes, such as steel slags, as effective support for iron oxide catalysts, which are also able to assist the catalytically active sites during their performances. Currently, steel slags are mainly used as building materials, nevertheless, sustainable reuse technologies are still desirable. Herein, the synthesis and characterization of several materials constituted of iron oxides onto steel slags in different mass ratio are reported. Their catalytic activity is also investigated in the reduction of nitrobenzene using iso-propanol as the hydrogen source in the absence of any added base
Assessment and source identification of pollution risk for touristic ports: Heavy metals and polycyclic aromatic hydrocarbons in sediments of 4 marinas of the Apulia region (Italy)
Full text linkThe Apulia region in Italy has the longest Adriatic coastline; thus, maritime tourism is the driving force for its economic development. Pollution risk for four representative touristic ports of the region was assessed by determining the concentrations of 10 metals, 16 polycyclic aromatic hydrocarbons (PAHs) congeners, and the main nutrients. The cumulative mean Effects Range–Median quotient (mERMq) was used to assess the hazard degree, while the distribution patterns and content ratios of different PAH sediment concentrations were investigated to identify the pollution sources. Principal component analyses indicated an anomalous pollution trend for one of the small touristic ports assessed; this trend emerged from contamination by heavy metals and PAHs to a larger extent than expected, considering the main activity in this port, especially in its inner basin. The reason of this anomaly is thought to be the hydrodynamic and/or other stress factors
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