An alternative way to determine the size distribution of airborne particulate matter

We developed and tested a methodology to extract both the size-segregated source apportionment of atmospheric aerosol and the size distribution of each detected element. The experiment is based on the parallel use of a standard low-volume sampler to collect Particulate Matter (PM) and an Optical Particle Counter (OPC). The approach is complementary to size-segregated PM sampling, and it was tested versus a 12-stage cascade impactor. Samples were collected inside the urban area of Genoa (Italy) and their elemental composition was measured by Energy Dispersive-X Ray Fluorescence (ED-XRF). Positive Matrix Factorization (PMF) was applied to time series of elemental concentrations to identify major PM sources, and both PM mass concentration and size-segregated particle number concentration were apportioned. Source profiles and temporal trends extracted by PMF were analyzed together with the OPC data to obtain the size distribution for several elements. The new methodology proved to be reliable for the PM apportionment as well as in providing the elemental concentrations in PM10, PM2.5, and PM1 (PM with aerodynamic diameter, D_ae < 10, 2.5, and 1 μm, respectively). The elemental size distributions are in good agreement with those obtained by the cascade impactor for several elements but some discrepancies, in particular for traffic emissions, are stressed and discussed in the text. The new methodology has two main advantages: it only requires standard semi-automatic sampling equipment and compositional analysis and it provides size-segregated information averaged over quite long periods (typically several months). This is particularly important since campaigns with cascade impactors are generally laborious and thus limited to short periods.     

Pesticide residues in artichokes: Effect of different head shape

Abstract

Residues of three pesticides (dimethoate, parathion, and pyrazophos) in two artichoke cultivars, Masedu and Spinoso sardo, were investigated. The amount of pesticides in artichokes was greatly affected by the head shape. In the case of the calix‐shaped Masedu artichoke, the residues in whole heads at commercial ripening were on average about twice higher than those of the pagoda‐shaped Spinoso sardo artichoke. In the heart this ratio was 4 to 42 times greater. Residue decay rates were very fast, mainly owing to the dilution effect due to head growth.     

Heavy metals removal and hydraulic performance in zero-valent iron/pumice permeable reactive barriers

Long-term behaviour is a major issue related to the use of zero-valent iron (ZVI) in permeable reactive barriers for groundwater remediation; in fact, in several published cases the hydraulic conductivity and removal efficiency were progressively reduced during operation, potentially compromising the functionality of the barrier. To solve this problem, the use of granular mixtures of ZVI and natural pumice has recently been proposed. This paper reports the results of column tests using aqueous nickel and copper solutions of various concentrations. Three configurations of reactive material (ZVI only, granular mixture of ZVI and pumice, and pumice and ZVI in series) are discussed. The results clearly demonstrate that iron-pumice granular mixtures perform well both in terms of contaminant removal and in maintaining the long-term hydraulic conductivity. Comparison with previous reports concerning copper removal by ZVI/sand mixtures reveals higher performance in the case of ZVI/pumice.     

Facile characterization of polymer fractions from waste electrical and electronic equipment (WEEE) for mechanical recycling

In view of the environmental problem involved in the management of WEEE, and then in the recycling of post-consumer plastic of WEEE there is a pressing need for rapid measurement technologies for simple identification of the various commercial plastic materials and of the several contaminants, to improve the recycling of such wastes.This research is focused on the characterization and recycling of two types of plastics, namely plastic from personal computer (grey plastic) and plastic from television (black plastic). Various analytical techniques were used to monitor the compositions of WEEE. Initially, the chemical structure of each plastic material was identified by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). Polymeric contaminants of these plastics, in particular brominated flame retardants (BFRs) were detected in grey plastics only using different techniques. These techniques are useful for a rapid, correct and economics identification of a large volumes of WEEE plastics.     

Urban air pollution monitoring and correlation properties between fixed-site stations

The rich regional air-monitoring network of the Emilia-Romagna region of Italy has been used to quantify the spatial variability of the main pollutants within urban environments and to analyze the correlations between stations. The spatial variability of the concentrations of the majority of pollutants within the city was very high, making it difficult to differentiate and characterize the urban environments and to apply legal limits with uniform criteria. On the other hand, the correlations between the fixed-site monitoring stations were high enough for their data to be retained generally very appropriately for controlling temporal trends. Starting from the high correlation level, a procedure was proposed and tested to derive pollution levels, using short-term measurements, such as passive samplers and mobile-station data. The importance of long-term statistics in urban air pollution mapping was emphasized. Treatment of missing data in time series and quality assurance were indicated as possible fields for applications for the correlation properties.     

Effects of exposure to ED contaminants (TPT-Cl and Fenarimol) on crinoid echinoderms: comparative analysis of regenerative development and correlated steroid levels

Regenerative phenomena reproduce developmental processes in adult organisms and are regulated by neuro-endocrine mechanisms. They can therefore provide sensitive tests for monitoring the effects of exposure to endocrine disrupter contaminants (EDs) which can be bioaccumulated by the organisms causing dysfunctions in steroid hormone metabolism and activities and affecting reproduction and development. Echinoderms are prime candidates for this new ecotoxicological approach, since (1) they offer unique models to study physiological regenerative processes and (2) in echinoderms vertebrate-type steroids can be synthesized and used as terminal hormones along the neuro-endocrine cascades regulating reproductive, growth and developmental processes. We are currently exploring the effects on the regenerative potential of echinoderms of different classes of compounds that are well known to have ED activity. The present paper focuses on the possible effects of well-known compounds with suspected androgenic activity such as TPT-Cl (Triphenyltin-chloride) and Fenarimol [(±)-2,4-dichloro-α-(pyrimidin-5-yl) benzhydryl alcohol]. The selected test-species is the crinoid Antedon mediterranea, a tractable and sensitive benthic filter-feeding species which represents a valuable experimental model for investigation on the regenerative process from the macroscopic to the molecular level. The present investigation employs an integrated approach which combines exposure experiments and biological analysis utilizing microscopy, immunocytochemistry and biochemistry. The experiments were carried out on experimentally induced arm regenerations in semistatic controlled conditions with exposure concentrations comparable to those of moderately polluted coastal zones. The bulk of results obtained so far provide indications of significant sublethal effects from exposure to TPT-Cl and Fenarimol and mechanisms of toxicity related to developmental physiology, which are associated with variations in steroid levels in the animal tissues. The results indicate that these two substances (1) affect growth and development by interfering with the same basic cellular mechanisms of regeneration, such as cell proliferation, migration and differentiation/dedifferentiation, which are possibly controlled by steroid hormones; and (2) can induce a number of significant modifications in the timing, modalities and pattern of arm regeneration, which may involve the activation of cell mechanisms related to steroid synthesis/metabolism. Physical and Chemical Impacts on Marine Organisms, a Bilateral Seminar Italy-Japan held in November 2004