| 11. |
- Lutz, Anna, 1986, et al.
(författare)
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Gas to Particle Partitioning of Organic Acids in the Boreal Atmosphere
- 2019
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Ingår i: Acs Earth and Space Chemistry. - : American Chemical Society (ACS). - 2472-3452. ; 3:7, s. 1279-1287
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Tidskriftsartikel (refereegranskat)abstract
- Gas to particle partitioning of carboxylic acids was investigated using a high-resolution chemical ionization time-of-flight mass spectrometer (HR-CI-ToF-MS) with the filter inlet for gases and aerosol (FIGAERO). Specifically, the partitioning coefficients of 640 components with unique molecular composition were calculated from an assumed linear relationship between [particle]/[gas] versus the mass of the organic fraction (M-org) according to Raoult's law, i.e., equilibrium phase partitioning. We demonstrate that, using the full data set, most of the compounds do not follow a linear relationship. This is especially the case for low- and high-molecular-weight species. Using a subset of the data, with concurrent low sulfate ambient observations ([SO42- < 0.4 mu g m(-3)), the relationship improved significantly and K-i could be derived from the slope of a linear regression to the data. The 100 species with the highest R-2 (>= 0.7) of this regression are presented. The restrictions during high sulfate conditions can be explained by changes in either the equilibrium conditions (e.g., the activity coeffient, gamma(i)) or uptake kinetics (mass transfer limitation). This study demonstrates that partitioning of compounds in the complex ambient atmosphere follows ideal Raoult's law for some limited conditions and stresses the need for studies also in more polluted environments.
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| 12. |
- Meng, X. X. Y., et al.
(författare)
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Humidity-Dependent Phase State of Gasoline Vehicle Emission-Related Aerosols
- 2021
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:2, s. 832-841
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Tidskriftsartikel (refereegranskat)abstract
- The phase states of primarily emitted and secondarily formed aerosols from gasoline vehicle exhausts were investigated by quantifying the particle rebound fraction (f). The rebound behaviors of gasoline vehicle emission-related aerosols varied with engines, fuel types, and photochemical aging time, showing distinguished differences from biogenic secondary organic aerosols. The nonliquid-to-liquid phase transition of primary aerosols emitted from port fuel injection (PFI) and gasoline direct injection (GDI) vehicles started at a relative humidity (RH) = 50 and 60%, and liquefaction was accomplished at 60 and 70%, respectively. The RH at which f declined to 0.5 decreased from 70 to 65% for the PFI case with 92# fuel, corresponding to the photochemical aging time from 0.37 to 4.62 days. For the GDI case, such RH enhanced from 60 to 65%. Our results can be used to imply the phase state of traffic-related aerosols and further understand their roles in urban atmospheric chemistry. Taking Beijing, China, as an example, traffic-related aerosols were mainly nonliquid during winter with the majority ambient RH below 50%, whereas they were mostly liquid during the morning rush hour of summer, and traffic-related secondary aerosols fluctuated between nonliquid and liquid during the daytime and tended to be liquid at night with increased ambient RH.
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| 13. |
- Ericson Jogsten, Ingrid, et al.
(författare)
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Exposure to perfluorinated compounds in Catalonia, Spain, through consumption of various raw and cooked foodstuffs, including packaged food
- 2009
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Ingår i: Food and Chemical Toxicology. - Amsterdam : Elsevier. - 0278-6915 .- 1873-6351. ; 47:7, s. 1577-1583
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the role that some food processing and packaging might play as a source of perfluorinated compounds (PFCs) through the diet was assessed. The levels of PFCs were determined in composite samples of veal steak (raw, grilled, and fried), pork loin (raw, grilled, and fried), chicken breast (raw, grilled, and fried), black pudding (uncooked), liver lamb (raw), marinated salmon (home-made and packaged), lettuce (fresh and packaged), pate of pork liver, foie gras of duck, frankfurt, sausages, chicken nuggets (fried), and common salt. Among the 11 PFCs analyzed, only PFHxS, PFOS, PFHxA, and PFOA were detected in at least one composite sample, while the levels of the remaining PFCs (PFBuS, PFHpA, PFNA, PFDA, PFUnDA, and PFDoDA) were under their respective detection limits. PFOS was the compound most frequently detected, being found in 8 of the 20 food items analyzed, while PFHxA was detected in samples of raw veal, chicken nuggets, frankfurt, sausages, and packaged lettuce. According to the results of the present study, it is not sufficiently clear if cooking with non-stick cookware, or packaging some foods, could contribute to a higher human exposure to PFCs.
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| 14. |
- Gustafsson, Jon Petter, et al.
(författare)
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Towards a consistent geochemical model for prediction of uranium(VI) removal from groundwater by ferrihydrite
- 2009
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Ingår i: Applied Geochemistry. - Oxford : Pergamon Press. - 0883-2927 .- 1872-9134. ; 24:3, s. 454-462
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Tidskriftsartikel (refereegranskat)abstract
- Uranium(VI), which is often elevated in granitoidic groundwaters, is known to adsorb strongly to Fe (hydr)oxides under certain conditions. This process can be used in water treatment to remove U(VI). To develop a consistent geochemical model for U(VI) adsorption to ferrihydrite, batch experiments were performed and previous data sets reviewed to optimize a set of surface complexation constants using the 3-plane CD-MUSIC model. To consider the effect of dissolved organic matter (DOM) on U(VI) speciation, new parameters for the Stockholm Humic Model (SHM) were optimized using previously published data. The model, which was constrained from available X-ray absorption fine structure (EXAFS) spectroscopy evidence, fitted the data well when the surface sites were divided into low- and high-affinity binding sites. Application of the model concept to other published data sets revealed differences in the reactivity of different ferrihydrites towards U(VI). Use of the optimized SHM parameters for U(VI)-DOM complexation showed that this process is important for U(VI) speciation at low pH. However in neutral to alkaline waters with substantial carbonate present, Ca–U–CO3 complexes predominate. The calibrated geochemical model was used to simulate U(VI) adsorption to ferrihydrite for a hypothetical groundwater in the presence of several competitive ions. The results showed that U(VI) adsorption was strong between pH 5 and 8. Also near the calcite saturation limit, where U(VI) adsorption was weakest according to the model, the adsorption percentage was predicted to be >80%. Hence U(VI) adsorption to ferrihydrite-containing sorbents may be used as a method to bring down U(VI) concentrations to acceptable levels in groundwater.
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| 15. |
- Li, J. J., et al.
(författare)
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Characterization of Aerosol Aging Potentials at Suburban Sites in Northern and Southern China Utilizing a Potential Aerosol Mass (Go:PAM) Reactor and an Aerosol Mass Spectrometer
- 2019
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Ingår i: Journal of Geophysical Research-Atmospheres. - : American Geophysical Union (AGU). - 2169-897X .- 2169-8996. ; 124:10, s. 5629-5649
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Tidskriftsartikel (refereegranskat)abstract
- Aerosol mass spectrometry was used to characterize submicron aerosols before and after aging in a Gothenburg Potential Aerosol Mass (Go:PAM) reactor at two suburban sites in China, one in northern China at Changping (CP), Beijing, and a second in southern China at Hong Kong (HK). Organic aerosol (OA) dominated in the ambient nonrefractory particulate matter <1m (NR-PM1) for both CP (42-71%) and HK (43-61%), with a large contribution from secondary OA factors that were semivolatile oxygenated (SVOOA) and low-volatility oxygenated (LVOOA). Under constant OH exposure, OA enhancement (78-98%) dominated the NR-PM1 mass increment at both sites, while nitrate was enhanced the most among the inorganic species (7-9%). Overall, the CP site exhibited higher OA oxidation potential and more enhancement of SVOOA than LVOOA (7.5 vs. 2.7g/m(3)), but the reverse was observed in HK (0.8 vs. 2.6g/m(3)). In CP, more enhancement of the less oxygenated SVOOA suggests that aerosol aging was more sensitive to the abundant locally emitted primary OA and volatile organic compound precursors. On the contrary, the more formation of the highly oxidized LVOOA in HK indicates that aerosol aging mainly escalated the degree of oxygenation of OA as ambient aerosol was already quite aged and there was a lack of volatile organic compound precursors. The comparative measurements using the same oxidation system reveal distinct key factors and mechanisms that influence secondary aerosol formation in two suburban locations in China, providing scientific insights to assist formulation of location-specific mitigation measures of secondary pollution. Plain Language Summary Atmospheric submicron particles have significant impacts on the climate and human health. A large part of these particles are formed secondarily through successive aging of primary emissions. To study such aging processes, we used a reactor that can provide highly oxidizing conditions to simulate the oxidation of ambient aerosols at accelerated rates. An online mass spectrometer was connected after the reactor to measure changes in aerosol mass concentration and chemical composition between the ambient samples and the oxidized ones. We presented the first comparative measurements of the aging potentials of ambient aerosols in two suburban sites in northern and southern China (Changping District in Beijing, and Hong Kong). Results showed that generally aerosols at the Changping site had higher aging potentials after passing through the oxidation reactor, probably due to more local emissions of precursors, while air masses in Hong Kong were already in a higher oxidation state with lower aging potentials, mainly because of strong impacts from long-range transported pollution sources. Distinct aerosol aging pathways related to different ambient precursors were observed at the two sites. Understanding of the different characteristics of aerosol aging processes can lead to advances in air quality modeling and pollution management.
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| 16. |
- Salvador, Christian Mark, 1989, et al.
(författare)
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Ambient nitro-aromatic compounds - biomass burning versus secondary formation in rural China
- 2021
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:3, s. 1389-1406
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Tidskriftsartikel (refereegranskat)abstract
- Nitro-aromatic compounds (NACs) were measured hourly at a rural site in China during wintertime to monitor the changes due to local and regional impacts of biomass burning (BB). Concurrent and continuous measurements of the concentrations of 16 NACs in the gas and particle phases were performed with a time-of-flight chemical ionization mass spectrometer (CIMS) equipped with a Filter Inlet for Gases and AEROsols (FIGAERO) unit using iodide as the reagent ion. NACs accounted for <2 % of the mass concentration of organic matter (OM) and total particulate matter (PM), but the total particle mass concentrations of these compounds can reach as high as 1000 ng m(-3) (299 ng m(-3) avg), suggesting that they may contribute significantly to the radiative forcing effects of atmospheric particles. Levels of gas-phase NACs were highest during the daytime (15:00-16:00 local time, LT), with a smaller night-time peak around 20:00LT. Box-model simulations showed that this occurred because the rate of NAC production from gas-phase sources exceeded the rate of loss, which occurred mainly via the OH reaction and to a lesser degree via photolysis. Data gathered during extended periods with high contributions from primary BB sources (resulting in 40 %-60 % increases in NAC concentrations) were used to characterize individual NACs with respect to gas-particle partitioning and the contributions of regional secondary processes (i.e. photochemical smog). On days without extensive BB, secondary formation was the dominant source of NACs, and NAC levels correlated strongly with the ambient ozone concentration. Analyses of individual NACs in the regionally aged plumes sampled on these days allowed precursors such as phenol and catechol to be linked to their NAC derivatives (i.e. nitrophenol and nitrocatechol). Correlation analysis using the high time resolution data and box-model simulation results constrained the relationships between these compounds and demonstrated the contribution of secondary formation processes. Furthermore, 13 of 16 NACS were classified according to primary or secondary formation process. Primary emission was the dominant source (accounting for 60 %-70 % of the measured concentrations) of 5 of the 16 studied NACs, but secondary formation was also a significant source. Photochemical smog thus has important effects on brown carbon levels even during wintertime periods dominated by primary air pollution in rural China.
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| 17. |
- Antonsen, Simen, et al.
(författare)
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Atmospheric Chemistry of tert-butylamine and AMP
- 2017
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Ingår i: Energy Procedia. Volume 114, 2017, Pages 1026-103213th International Conference on Greenhouse Gas Control Technologies, GHGT 2016; Lausanne; Switzerland; 14 November 2016 through 18 November 2016. - : Elsevier BV. - 1876-6102.
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Konferensbidrag (refereegranskat)abstract
- © 2017 The Authors. The atmospheric chemistry of (CH 3 ) 3 CNH 2 (tert-butylamine, tBA) and (CH 3 ) 2 (CH 2 OH)CNH 2 (2-amino-2-methyl-1-propanol, AMP) has been studied by quantum chemistry methods and in photo-oxidation experiments in the EUPHORE chamber in Valencia (Spain). Aerosol formation and composition has been quantified. Yields of nitramines and other products in the photo-oxidations have been determined and complete photo-oxidation schemes including branching between the major reaction routes have been obtained. Published by Elsevier Ltd.
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| 18. |
- Gustavsson, Lillemor, et al.
(författare)
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Reed beds receiving industrial sludge containing nitroaromatic compounds : Effects of outgoing water and bed material extracts in the umu-c genotoxicity assay, DR-CALUX assay and on early life stage development in Zebrafish (Danio rerio)
- 2007
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Ingår i: Environmental Science and Pollution Research. - Berlin : Springer. - 0944-1344 .- 1614-7499. ; 14:3, s. 202-211
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Tidskriftsartikel (refereegranskat)abstract
- Goal, Scope and Background: Sweden has prohibited the deposition of organic waste since January, 2005. Since 1 million tons of sludge is produced every year in Sweden and the capacity for incineration does not fill the demands, other methods of sludge management have to be introduced to a larger degree. One common method in the USA and parts of Europe is the use of wetlands to treat wastewater and sewage sludge. The capacity of reed beds to affect the toxicity of a complex mixture of nitroaromatics in sludge, however, is not fully elucidated. In this study, an industrial sludge containing explosives and pharmaceutical residues was therefore treated in artificial reed beds and the change in toxicity was studied. Nitroaromatic compounds, which are the main ingredients of many pharmaceuticals and explosives, are well known to cause cytotoxicity and genotoxicity. Recently performed studies have also showed that embryos of zebrafish (Danio rerio) are sensitive to nitroaromatic compounds. Therefore, we tested the sludge passing through constructed wetlands in order to detect any changes in levels of embryotoxicity, genotoxicity and dioxin-like activity (AhR-agonists). We also compared unplanted and planted systems in order to examine the impact of the root system on the fate of the toxicants. Methods: An industrial sludge containing a complex mixture of nitroaromatics was added daily to small-scale constructed wetlands (vertical flow), both unplanted and planted with Phragmites australis. Sludge with an average dry weight of 1.25%, was added with an average hydraulic loading rate of 1.2 L/day. Outgoing water was collected daily and stored at −20°C. The artificial wetland sediment was Soxhlet extracted, followed by clean-up with multi-layer silica, or extracted by ultrasonic treatment, yielding one organic extract and one water extract of the same sample. Genotoxicity of the extracts was measured according to the ISO protocol for the umu-C genotoxicity assay (ISO/TC 147/SC 5/WG9 N8), using Salmonella typhimurium TA1535/pSK1002 as test organism. Embryotoxicity and teratogenicity were studied using the fish egg assay with zebrafish (Danio rerio) and the dioxin-like activity was measured using the DR-CALUX assay. Chemical analyses of nitroaromatic compounds were performed using Solid Phase Micro Extraction (SPME) and GC-MS. Results: Organic extracts of the bed material showed toxic potential in all three toxicity tests after two years of sludge loading. There was a difference between the planted and the unplanted beds, where the toxicity of organic extracts overall was higher in the bed material from the planted beds. The higher toxicity of the planted beds could have been caused by the higher levels of total carbon in the planted beds, which binds organic toxicants, and by enrichment caused by lower volumes of outgoing water from the planted beds. Discussion: Developmental disorders were observed in zebrafish exposed directly in contact to bed material from unplanted beds, but not in fish exposed to bed material from planted beds. Hatching rates were slightly lower in zebrafish exposed to outgoing water from unplanted beds than in embryos exposed to outgoing water from planted beds. Genotoxicity in the outgoing water was below detection limit for both planted and unplanted beds. Most of the added toxicants via the sludge were unaccounted for in the outgoing water, suggesting that the beds had toxicant removal potential, although the mechanisms behind this remain unknown. Conclusions: During the experimental period, the beds received a sludge volume (dry weight) of around three times their own volume. In spite of this, the toxicity in the bed material was lower than in the sludge. Thus, the beds were probably able to actually decrease the toxicity of the added, sludge-associated toxicants. When testing the acetone extracts of the bed material, the planted bed showed a higher toxicity than the unplanted beds in all three toxicity tests. The toxicity of water extracts from the unplanted beds, detected by the fish egg assay, were higher than the water extracts from the planted beds. No genotoxicity was detected in outgoing water from either planted or unplanted beds. All this together indicates that the planted reed beds retained semi-lipophilic acetone-soluble toxic compounds from the sludge better than the unplanted beds, which tended to leak out more of the water soluble toxic compounds in the outgoing water. The compounds identified by SPME/GC in the outgoing water were not in sufficient concentrations to have caused induction in the genotoxicity test. Recommendations and Perspectives: This study has pointed out the benefits of using constructed wetlands receiving an industrial sludge containing a complex mixture of nitroaromatics to reduce toxicity in the outgoing water. The water from planted, constructed wetlands could therefore be directed to a recipient without further cleaning. The bed material should be investigated over a longer period of time in order to evaluate potential accumulation and leakage prior to proper usage or storage. The plants should be investigated in order to examine uptake and possible release when the plant biomass is degraded.
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| 19. |
- Otte, Jens C., et al.
(författare)
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A bioassay approach to determine the dioxin-like activity in sediment extracts from the Danube River : ethoxyresorufin-O-deethylase induction in gill filaments and liver of three-spined sticklebacks (Gasterosteus aculeatus L.)
- 2008
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Ingår i: Environment International. - Amsterdam : Elsevier. - 0160-4120 .- 1873-6750. ; 34:8, s. 1176-1184
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Tidskriftsartikel (refereegranskat)abstract
- Sediment samples from the upper Danube River in Germany have previously been characterized as ecotoxicologically hazardous and contaminants in these sediments may contribute to the observed decline of fish populations in this river section. For the investigation of sediment toxicity there is a need for development, standardization and implementation of in vivo test systems using vertebrates. Therefore, the main objective of this study was to apply and evaluate a recently established fish gill EROD assay as a biomarker in sediment toxicity assessment by using extracts of well characterised sediment samples from the upper Danube River. This to our knowledge is the first application of this novel assay to sediment extracts. Sediments from four different sites along the upper Danube River were Soxhlet-extracted with acetone and dissolved in DMSO. Three-spined sticklebacks (Gasterosteus aculeatus L.) were exposed for 48 h to various concentrations of the extracts, to the positive control β-naphthoflavone or to the solvent. Measurements of EROD activity in gill filaments and liver microsomes followed the exposure. Concentration-dependent induction of EROD in both gill and liver was found for all sediment extracts. The highest EROD-inducing potency was determined for extracts of sediments from the sites “Öpfinger See” and “Sigmaringen” and the EROD activities in gill and liver correlated well. The results from the gill and liver assays were in accordance with in vitro results of previous investigations. The EROD activities measured in the present study corresponded with the concentrations of PAHs, PCBs and PCDD/Fs in the sediment samples derived in a previous study. The sticklebacks in this study were in the reproductive phase and a stronger EROD induction was obtained in the females than in the males. Implementation of the EROD assay in testing of sediment extracts gave highly reliable results which make this assay an ecotoxicologically relevant method for assessment of contamination with Ah receptor agonists in sediments.
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| 20. |
- Li, J., et al.
(författare)
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Hygroscopicity of Fresh and Aged Salt Mixtures from Saline Lakes
- 2021
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Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- The high hygroscopicity of salt aerosol particles makes the particles active in aerosol and cloud formations. Inland saline lakes are an important and dynamic source of salt aerosol. The salt particles can be mixed with mineral dust and transported over long distances. During transportation, these particles participate in atmospheric heterogeneous chemistry and further impact the climate and air quality on a global scale. Despite their importance and potential, relatively little research has been done on saline lake salt mixtures from atmospheric perspectives. In this study, we use experimental and model methods to evaluate the hygroscopic properties of saline lake brines, fresh salt aerosol particles, and aged salt aerosol particles. Both original samples and literature data are investigated. The original brine samples are collected from six salt lakes in Shanxi and Qinghai provinces in China. The ionic compositions of the brines are determined and the hygroscopicity measurements are performed on crystallized brines. The experimental results agree well with theoretical deliquescence relative humidity (DRH) values estimated by a thermodynamic model. The correlations between DRHs of different salt components and the correlations between DRHs and ionic concentrations are presented and discussed. Positive matrix factorization (PMF) analysis is performed on the ionic concentrations data and the hygroscopicity results, and the solutions are interpreted and discussed. The fresh and aged salt aerosol particles are analyzed in the same way as the brines, and the comparison shows that the aged salt aerosol particles completely alter their hygroscopic property, i.e., transferring from MgCl2- governed to NH4NO3- governed.
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