New developments on emerging organic pollutants in the atmosphere
ABSTRACT BACKGROUND: The continuous progress in analytical techniques has improved the capability of detecting chemicals and recognizing new substances and extended the list of detectable contaminants widespread in all environmental compartments by human activities. Most concern is focused on water contamination by emerging compounds. By contrast, scarce attention is paid to the atmospheric sector, which in most cases represents the pathway of diffusion at local or global scale. Information concerning a list of organic pollutants is provided in this paper. METHODS: The volatile methyl tert-butyl ether and siloxanes are taken as examples of information insufficient with regard to the potential risk induced by diffusion in the atmosphere. Illicit drugs, whose presence in the air was ascertained although by far unexpected, are considered to stress the needs of investigating not solely the environmental compartments where toxic substances are suspected to display their major influence. Finally, the identification of two recognized emerging contaminants, i.e., tris(2-chloroisopropyl) phosphate and N,N-diethyl-m-toluamide, in aerosols originally run to characterize other target compounds is presented with the purpose of underlining the wide diffusion of the organic emerging contaminants in the environment.
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ABSTRACT: Humic substances (HS) acting as photosensitizers can generate a variety of reactive species, such as OH radicals and excited triplet states ((3)HS(*)), promoting the degradation of organic compounds. Here we apply compound-specific stable isotope analysis (CSIA) to characterize photosensitized mechanisms employing fuel oxygenates, such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), as probes. In oxygenated aqueous media, Λ (∆δ(2)H/∆δ(13)C) values of 23 ± 3 and 21 ± 3 for ETBE obtained by photosensitization by Pahokee Peat Humic Acid (PPHA) and Suwannee River Fulvic Acid (SRFA), respectively, were in the range typical for H-abstraction by OH radicals generated by photolysis of H2O2 (Λ = 24 ± 2). However, (3)HS(*) may become a predominant reactive species upon the quenching of OH radicals (Λ = 13.7 ± 0.9), and this process can also play a key role in the degradation of ETBE by PPHA photosensitization in deoxygenated media (Λ = 11 ± 1). This is in agreement with a model photosensitization by rose bengal (RB(2-)) in deoxygenated aqueous solutions resulting in one-electron oxidation of ETBE (Λ = 14 ± 1). Our results demonstrate that the use of CSIA could open new avenues for the assessment of photosensitization pathways.Environmental Science and Technology 11/2014; 49(1). DOI:10.1021/es502791f · 5.48 Impact Factor
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ABSTRACT: Nanoparticles are the largest fraction of aerosol loading by number. Knowledge of the chemical components present in nanoparticulate matter is needed to understand nanoparticle health and climatic impacts. In this work, we present field measurements using the Nano Aerosol Mass Spectrometer (NAMS), which provides quantitative elemental composition of nanoparticles around 20 nm diameter. NAMS measurements indicate that the element silicon (Si) is a frequent component of nanoparticles. Nanoparticulate Si is most abundant in locations heavily impacted by anthropogenic activities. Wind direction correlations suggest the sources of Si are diffuse, and diurnal trends suggest nanoparticulate Si may result from photochemical processing of gas phase Si-containing compounds, such as cyclic siloxanes. Atmospheric modeling of oxidized cyclic siloxanes is consistent with a diffuse photochemical source of aerosol Si. More broadly, these observations indicate a previously overlooked anthropogenic source of nanoaerosol mass. Further investigation is needed to fully resolve its atmospheric role.Environmental Science and Technology 09/2014; 48(19). DOI:10.1021/es5026933 · 5.48 Impact Factor
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ABSTRACT: The consequences of direct or indirect actions of the modern way of life on the environment have been targets of constant concern with respect to the future of the planet. Several substances that are inadequately disposed of as well as compounds that are not yet recognized as contaminants, have been showing increased levels in the environment and some toxic effects have already being reported. Polybrominated diphenyl ether (PBDE), a group of flame retardants released from consumer goods into the environment by different means such as volatilization after direct disposal or during production, can be considered in this context. PBDEs show high lipophilicity, resistance to degradation and bioaccumulative potential, being classified as persistent organic pollutants (POP), resulting in high levels of PBDEs in the environment (air, water and sediments), biota and humans. Some toxic effects observed in the organisms have been associated with the presence of PBDEs, such as their action as endocrine disruptors in humans and the biota, although their toxic mechanism is not completely understood and No part of this digital document may be reproduced, stored in a retrieval system or transmitted commercially in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services.Advances in environmental research. Volume 28, Edited by Justin A. Daniels, 01/2013: chapter POLYBROMINATED DIPHENYL ETHER (PBDE) FLAME RETARDANTS AS EMERGENT ENVIRONMENTAL POLLUTANTS: AN OVERVIEW OF THEIR ENVIRONMENTAL CONTAMINATION AND TOXICOLOGICAL PROPERTIES: pages 29; Nova Science Publishers, Inc.., ISBN: 978-1-62417-738-5