elemental concentration in atmospheric particulate matter estimation of nanoparticle contribution

Atmospheric nanoparticles (NPs) are often contained in aggregates or included in larger particles. We show that some of these structures can be crushed in water media by the application of ultrasounds, leading to a suspension of insoluble NPs. The contribution of these NPs to the total elemental concentration is evaluated as the difference between the inductively coupled plasma (ICP-MS) analysis before and after the elution of the suspension from an ion exchange cartridge. Total elemental content in PM can be therefore fractionated into three contributions - soluble species, solid NPs released from larger structures, insoluble particles - that may likely have different health and environmental effects. The method was applied to both Certified Material NIST 1649a and size-segregated atmospheric PM samples collected by a 13-stage impactor. The results indicate that alkaline and alkaline earth metals are found in the suspension only as watersoluble species, also when they are contained in the fine fraction of PM. Instead, a significant fraction of most elements typically emitted from combustion sources (Pb, Sb, Sn, Cd, V and As) is present in fine PM as insoluble nanoparticles that are easily dispersed in water under ultrasound application

Sunscreens Cause Coral Bleaching by Promoting Viral Infections

Background: Coral bleaching (i.e., the release of coral symbiotic zooxanthellae) has negative impacts on biodiversity and functioning of reef ecosystems and their production of goods and services. This increasing world-wide phenomenon is associated with temperature anomalies, high irradiance, pollution, and bacterial diseases. Recently, it has been demonstrated that personal can products, including sunscreens, have an impact on aquatic organisms similar to that of other contaminants. Objectives: Our goal was to evaluate the potential impact of sunscreen ingredients on hard corals and their symbiotic algae. Methods: In situ and laboratory experiments were conducted in several tropical regions (the Atlantic, Indian, and Pacific Oceans, and the Red Sea) by supplementing coral branches with aliquots of sunscreens and common ultraviolet filters contained in sunscreen formula. Zooxanthellae were checked for viral infection by epifluorescence and transmission electron microscopy analyses. Results: Sunscreens cause the rapid and complete bleaching of hard corals, even at extremely low concentrations. The effect of sunscreens is due to organic ultraviolet filters, which are able to induce the lyric viral cycle in symbiotic zooxanthellae with latent infections. Conclusions: We conclude that sunscreens, by promoting viral infection, potentially play an important role in coral bleaching in areas prone to high levels of recreational use by humans

The efficacy of imatinib mesylate in patients with FIP1L1-PDGFRα-positive hypereosinophilic syndrome. Results of a multicenter prospective study

BACKGROUND AND OBJECTIVES: The hypereosinophilic syndrome (HES) may be associated with the fusion of the platelet derived growth factor receptor a (PDGFRalpha) gene with the FIP1L1 gene in chromosome 4 coding for a constitutively activated PDGFRalpha tyrosine kinase. These cases with FIP1L1-PDGFRalpha rearrangement have been reported to be very sensitive to the tyrosine kinase inhibitor imatinib mesylate. DESIGN AND METHODS: A prospective multicenter study of idiopathic or primary HES was established in 2001 (Study Protocol Registration no. NCT 0027 6929). One hundred and ninety-six patients were screened, of whom 72 where identified as having idiopathic or primary HES and 63 were treated with imatinib 100 to 400 mg daily. RESULTS: Twenty-seven male patients carried the FIP1L1-PDGFRalpha rearrangement. All 27 achieved a complete hematologic remission (CHR) and became negative for the fusion transcripts according to reverse transcriptase polymerase chain reaction (RT-PCR) analysis. With a median follow-up of 25 months (15-60 months) all 27 patients remain in CHR and RT-PCR negative, and continue treatment at a dose of 100 to 400 mg daily. In three patients imatinib treatment was discontinued for few months, the fusion transcript became rapidly detectable, and then again undetectable upon treatment reassumption. Thirty-six patients did not carry the rearrangement; of these, five (14%) achieved a CHR, which was lost in all cases after 1 to 15 months. INTERPRETATION AND CONCLUSIONS: All patients meeting the criteria for idiopathic or primary HES should be screened for the FIP1L1-PDGFRalpha rearrangement. For all patients with this rearrangement, chronic imatinib treatment at doses as low as 100 mg daily ensures complete and durable responses

Determination of Sb(III), Sb(V) and identification of Sb-containing nanoparticles in airborne particulate matter

A reliable method able to separate and quantify Sb(III) and Sb(V) species by ion chromatography - inductively coupled plasma - mass spectrometry (IC-ICP-MS) was applied to PM samples from brakes, major source of antimony in coarse particles, and to atmospheric PM10 and size segregated samples. For brake samples we obtained recovery percentages of the IC-ICP-MS vs. ICP-MS analysis close to 100%. In PM samples the two inorganic species were detected only in the coarse fraction. The low recovery percentages obtained for fine particles suggest the presence of nano-particles aggregates in the analysed solutions, which are retained by the chromatographic column. (C) 2009 Published by Elsevier B

Characterisation of the traffic sources of PM through size-segregated sampling, sequential leaching and ICP analysis

A study of the elemental composition and size distribution of atmospheric particulate matter and of its spatial and temporal variability has been conducted at two traffic sites and one urban background site in the area of Rome, Italy. Chemical analysis included the fractionation of 22 elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe,Mg, Mn, Na, Ni, Pb, S, Sb, Si, Sn, Sr, Ti, Tl, V) into a water-extractable and a residual fraction. Size distribution analysis included measurements of aerosols in twelve size classes in the range 0.03–10 mm. The simultaneous determination of PM10 and PM2.5 at three sites during a 2-week study allowed the necessary evaluation of space and time concentration variations. The application of a chemical fractionation procedure to size-segregated samples proved to be a valuable approach for the characterisation of PM and for discriminating different emission sources. Extractable and residual fractions of the elements showed in fact different size distributions: for almost all elements the extractable fraction was mainly distributed in the fine particle size, while the residual fraction was in general predominant in the coarse size range. For some elements (As, Cd, Sb, Sn, V) the dimensional separation between the extractable fraction, almost quantitatively present in the fine mode particles, and the residual fraction, mainly distributed in the coarse mode particles, was almost quantitative. Under these conditions, the application of the chemical fractionation procedure to PM10 samples allows a clear distinction between contributes originating from fine and coarse particle emission sources. The results related to PM(10–2.5) and PM2.5 daily samples confirmed that chemical fractionation analysis increases the selectivity of most elements as source tracers. Extractable and residual fractions of As, Mg, Ni, Pb, S, Sn, Tl, Sb, Cd and V showed different time patterns and different spatial and size distributions, clearly indicating that the two chemical fractions are provided by different emission sources. The extractable fractions of As, Pb, Sn, S, Tl and V, in agreement to their dimensional distribution, were almost completely associated to PM2.5 and showed the same time pattern at all three sites, revealing the presence of spatially homogeneous sources. On the other hand, for most elements the relevant increase of PM10 elemental concentration from background stations to traffic urban stations can be attributed almost completely to the residual fraction of coarse particles. Taking into account temporal and size variability, the residual fractions of all these elements showed a very consistent co-variation, which indicates a prevailing common source of coarse particles; this has been identified in nontailpipe traffic source (road dust re-suspension, brake and tyre ware)

Relevance of Sb(III), Sb(V), and Sb-containing nano-particles in urban atmospheric particulate matter

A quick and reliable analytical method for the separation and quantification of extractable Sb(III) and Sb (V) in atmospheric particulate matter (PM) by ion chromatography( IC)-inductively coupled plasma-mass spectrometry (ICP-MS) has been optimized, validated on pairs of real, equivalent PM(10) samples and applied to a field monitoring campaign in a urban site. Both Sb(III) and Sb(V) forms were detected in real samples with Sb(III)/Sb(V) ratios up to 1.5. These two Sb species accounts only for a portion, of variable magnitude, of the total extractable Sb (10-70%); anyway, no other soluble Sb species were detected in the samples. The analysis of size-segregated samples collected by a 13-stage impactor showed that the recovery of [Sb(III) + Sb(V)] versus total extractable Sb is almost quantitative in the coarse fraction while it is below than 10% in the fine fraction. In the extracted solution from particles below 1 mu m we could highlight the presence of Sb-containing suspended solid nano-particles, which probably constitute the missing fraction. The contribution of nano-particles can be estimated as the difference between ICP-MS and IC-ICP-MS data, as small size solid bodies are able to pass through the nebulizer and reach the plasma torch, while they are retained by the chromatographic column. The aggregation state of these nano-particles seems to be easily altered when they are suspended in a water solution; a similar behavior could be hypothesized when in contact with biological fluids. It has been confirmed that brake pad abrasion is the prevalent source of Sb(III) in PM and that Sb(V) may be formed by oxidation during the braking processes. Differing from other environmental matrices, there is no evidence of any spontaneous oxidative conversion within the two species

Analisi elementare di campioni di PM10 ad elevata risoluzione temporale

La disponibilità di dati ad elevata risoluzione temporale fornisce un valido supporto per la valutazione dei numerosi fattori (come parametri meteorologici, flussi emissivi, reattività etc.) che influenzano le concentrazioni di inquinanti in atmosfera. In questo lavoro viene descritta l’ottimizzazione e la validazione di una procedura analitica per la determinazione mediante ICP-MS della frazione idrosolubile di 16 elementi in campioni di PM10 prelevati a risoluzione bioraria. La metodica può essere applicata direttamente su filtri in teflon campionati a 2.3 m3/h ed è facilmente trasferibile all’impiego routinario in laboratori chimici di monitoraggio ambientale. L’applicazione della metodica ad una prima breve campagna di monitoraggio a Roma (18-28 aprile 2008), ha permesso di esaminare interessanti relazioni tra le strutture temporali delle concentrazioni elementari misurate. Pur essendo ancora del tutto preliminari, i risultati ottenuti evidenziano prospettive interpretative decisamente interessanti. In particolare, si è verificata nell’intero periodo, una perfetta sovrapposizione tra le concentrazioni di Na e Mg solubile, (con un R2 = 0.99), confermando l’affidabilità del Mg solubile come tracciante di eventi di aerosol marino [1]. I due episodi di trasporto di aerosol marino evidenziati, sono stati differenziati mediante il confronto tra le strutture temporali fini dei due traccianti e di altri elementi in traccia di origine prevalentemente antropica, quali Tl, V, Pb e Zn, ed è stata evidenziata, come confermato dall’applicazione del modello Hysplit, una diversa provenienza delle masse d’aria. In corrispondenza delle precipitazioni, si nota inoltre la diversa modulazione delle concentrazioni dei diversi elementi nei fenomeni di “wash out” e “rain out”: mentre infatti la deposizione di tipo “wash out” causa una brusca diminuzione della concentrazione di tutti gli elementi, in presenza di deposizione “rain out” è possibile osservare una certa selettività. La disponibilità di dati ad elevata risoluzione temporale ha infine permesso di esaminare le relazioni tra le concentrazioni elementari, i flussi di traffico veicolare e l’altezza del PBL, stimata mediante la misura della radioattività naturale associata al radon222 (PBL Mixing Monitor, FAI Instruments, Fontenuova, RM-I). Per alcuni elementi (Cu, Sr, Ba, Mn, Zn), che presentano tra loro una correlazione superiore a 0.9 e che possono essere considerati traccianti piuttosto selettivi del contributo da risollevamento ed abrasione di parti meccaniche da traffico veicolare, si è osservato un comportamento abbastanza analogo a quello di inquinanti primari non reattivi da traffico veicolare [1]. In particolare, la struttura temporale mostra evidenti picchi di concentrazione nelle ore serali e di prima mattina, in corrispondenza cioè della concomitanza di un flusso veicolare sostenuto e di una altezza ridotta del PBL. Durante la notte, in condizioni di scarso rimescolamento e di un flusso emissivo ridotto, le concentrazioni subiscono una riduzione abbastanza rapida, probabilmente imputabile a fenomeni di deposizione secca. Le concentrazioni subiscono una rapida diminuzione anche nelle ore centrali della giornata, caratterizzate da un sostenuto flusso emissivo, ma da condizioni di buon rimescolamento delle masse di aria