Comparison of pressurized fluid extraction, Soxhlet extraction and sonication for the determination of polycyclic aromatic hydrocarbons in urban air and diesel exhaust particulate matter

In order to characterize and compare the chemical composition of diesel particulate matter and ambient air samples collected on filters, different extraction procedures were tested and their extraction efficiencies and recoveries determined. This study is an evaluation of extraction methods using the standard 16 EPA PAHs with HPLC fluorescence analysis. Including LC analysis also GC and MS methods for the determination of PAHs can be used. Soxhlet extraction was compared with ultrasonic agitation and pressurized fluid extraction (PFE) using three solvents to extract PAHs from diesel exhaust and urban air particulates. The selected PAH compounds of soluble organic fractions were analyzed by HPLC with a multiple wavelength shift fluorescence detector. The EPA standard mixture of 16 PAH compounds was used as a standard to identify and quantify diesel exhaust-derived PAHs. The most effective extraction method of those tested was pressurized fluid extraction using dichloromethane as a solvent.     

A web-based Decision Support System for the optimal management of construction and demolition waste

Wastes from construction activities constitute nowadays the largest by quantity fraction of solid wastes in urban areas. In addition, it is widely accepted that the particular waste stream contains hazardous materials, such as insulating materials, plastic frames of doors, windows, etc. Their uncontrolled disposal result to long-term pollution costs, resource overuse and wasted energy. Within the framework of the DEWAM project, a web-based Decision Support System (DSS) application - namely DeconRCM - has been developed, aiming towards the identification of the optimal construction and demolition waste (CDW) management strategy that minimises end-of-life costs and maximises the recovery of salvaged building materials. This paper addresses both technical and functional structure of the developed web-based application. The web-based DSS provides an accurate estimation of the generated CDW quantities of twenty-one different waste streams (e.g. concrete, bricks, glass, etc.) for four different types of buildings (residential, office, commercial and industrial). With the use of mathematical programming, the DeconRCM provides also the user with the optimal end-of-life management alternative, taking into consideration both economic and environmental criteria. The DSS's capabilities are illustrated through a real world case study of a typical five floor apartment building in Thessaloniki, Greece.     

Critical ranges of pollution indices: a tool for predicting soil metal pollution under long-term wastewater reuse

A greenhouse experiment was conducted in pots, for two years (2015–2016), in Amaliada, Greece, using a randomized block design, including six treatments with mixtures composed of Zn, Mn, Cd, Co, Cu, Cr, Ni, and Pb, each metal taking part in the mixture at concentrations of 0, 10, 20, 30 40, and 50 mg/kg soil in four replicates each. Beta vulgaris (beet) was used as a test plant. The aim of the experiment was to calibrate the following pollution indices: “pollution load index,” “elemental pollution index,” “heavy metal load,” and “total concentration factor,” in order to determine the level of soil pollution under variable levels (low to very high) of metal mixtures. The irrigation of the plants was conducted with treated municipal wastewater based on field capacity and percent wilting point. The above pollution indices were classified into four soil pollution classes, i.e., “optimum,” “low,” “high” and “very high” on the basis of percent dry matter plant losses.     

Application of multivariate statistical methods for groundwater physicochemical and biological quality assessment in the context of public health

Three representative areas (lowland, semi-mountainous, and coastal) have been selected for the collection of drinking water samples, and a total number of 28 physical, chemical, and biological parameters per water sample have been determined and analyzed. The mean values of the physical and chemical parameters were found to be within the limits mentioned in the 98/83/EEC directive. The analysis of biological parameters shows that many of the water samples are inadequate for human consumption because of the presence of bacteria. Cluster analysis (CA) first was used to classify sample sites with similar properties and results in three groups of sites; discriminant analysis (DA) was used to construct the best discriminant functions to confirm the clusters determined by CA and evaluate the spatial variations in water quality. The standard mode discriminant functions, using 17 parameters, yielded classification matrix correctly assigning 96.97% of the cases. In the stepwise mode, the DA produced a classification matrix with 96.36% correct assignments using only ten parameters (EC, Cl^???, NO₃ ^???, HCO₃ ^???, CO₃ ^???2, Ca^?+?2, Na^?+?, Zn, Mn, and Pb). CA and factor analysis (FA) are used to characterize water quality and assist in water quality monitoring planning. CA proved that two major groups of similarity (six subclusters) between 17 physicochemical parameters are formed, and FA extracts six factors that account for 66.478% of the total water quality variation, when all samples’ physicochemical data set is considered. It is noteworthy that the classification scheme obtained by CA is completely confirmed by principal component analysis.     

Merthyr Mawr: a case study for the assessment of nitrate at humid dunes in England and Wales

Humid dunes in the UK are at risk from nutrient pressures from multiple sources. The Water Framework Directive 2000/60/EC (WFD) requires assessment and identification of these pressures with appropriate measures defined to mitigate against further damage. We discuss the application of nitrate threshold values for the WFD classification, illustrating this with a case study at Merthyr Mawr, South Wales, where ephemeral groundwater discharge from a spring (‘Burrows Well’) sourced within the Carboniferous Limestone, creates a large dune slack. Ecological surveys suggest that the vegetation in this slack was in unfavourable condition, due to high levels of nitrate. Applying the source-pathway-receptor model an investigation was undertaken to improve the conceptual model and assess the significance of damage from groundwater derived nutrients. Results show groundwater nitrate concentrations?~?10 mg/l as NO₃-N feeding the main slack waters. The vegetation survey data shows clear evidence of ecological damage, and the hydrogeological data traces the source of this back to the Carboniferous Limestone aquifer and not the overlying blown sands. Discharging groundwater is the source of the enrichment. Isotopic analysis suggests that the N is derived from inorganic fertilizer and/or atmospheric N. During the first cycle WFD characterisation the unfavourable status of the dunes due to chemical groundwater pressure resulted in a failure of the surrounding groundwater body, which was designated as poor status. The site has been re assessed for the 2nd Cycle WFD characterisation where recently developed nitrate ‘threshold’ values have been applied to assess the significance of damage for groundwater derived nutrients. The surrounding Carboniferous Limestone catchment is complex and could not be sufficiently constrained, thus land management changes could not be targeted. The paucity of historical or repeat vegetation surveys limits our ability to measure change within the dune vegetation and causes difficulties in understanding the impact of multiple pressures.     

PM10 regional transport pathways in Thessaloniki,Greece

In this study, the most dominant regional transport pathways for the city of Thessaloniki, Greece were identified and linked to air quality issues with respect to particulate matter (PM). Using air mass trajectories, cluster analysis techniques and PM10 measurements of a background-urban station of the greater Thessaloniki area during 2001–2004, it was found that north-eastern and southern flows were the most frequent in appearance with high potential to influence the city of Thessaloniki, especially when coinciding with biomass burning or Saharan dust events correspondingly. These incidents appeared to occur mostly during summer adding to a PM10 monthly mean up to 10 μg m^?3. High concentrations of surface PM10 related to north-eastern flows were in most cases accompanied with high aerosol columnar optical depths implying that particulate matter transport from the North-East was multi-layered. South-southwesterly flows originating from N. Africa, though less frequent, seemed to affect decisively Thessaloniki's aerosol budget especially during transition seasons. These flows were related with an increase of the monthly PM10 average up to 20–30 μg m^?3 for the time period studied. Finally, northerly flows were found to transport rather clean air masses that did not seem to contribute to the air quality deterioration of the city.