Biodegradation of 4-nonylphenol in seawater and sediment

Biodegradation of 14C-labelled nonylphenol at the concentration 11 microg litre (-1) in seawater has been estimated by collection and quantification of the formed labelled carbon dioxide. Initially degradation was very slow but when the microorganisms had become adapted, after four weeks at 11 degrees C, the degradation rate increased rapidly and after 58 days about 50% of 14C from NP was found in the CO2 fraction. In the presence of sediment the initial degradation rate was high and did not increase after longer incubation. Lack of oxygen reduced the degradation rate by half in the presence of sediment.     

A gas-phase biosensor for environmental monitoring of formic acid: laboratory and field validation

In order to encourage more exposure measurements to be performed, a formic acid gas-phase biosensor has been developed for this purpose. In the present paper, an enzyme based biosensor has been validated with respect to analyte selectivity and on-site use. To ensure that the sampler developed measures the compound of interest the biosensor was exposed to three near structural homologues to formic acid, i.e. acetic acid, methanol and formaldehyde. These vapours were generated with and without formic acid and the only compound that was found to have an effect on the performance of the biosensor, albeit a small one, was acetic acid. The field test was performed in a factory using formic acid-containing glue for glulam products. In parallel to the measurements with the biosensor a well defined reference method was used for sampling and analysing formic acid. It was found that the biosensor worked satisfactorily in this environment when used in a stationary position. It was also shown that the biosensor could determine formic acid vapour concentrations down to 0.03 mg m(-3).     

Introduction of cob(I)alamin as an analytical tool: application to reaction-kinetic studies of oxiranes

The strongly nucleophilic cob(I)alamin, i.e. Vitamin B₁₂ with Co(III) reduced to Co(I), is introduced as a trapping agent in the determination of concentrations of electrophilic reagents. This compound was applied, in comparison with the previously used moderately reactive nicotinamide (H.J.C.F. Nelis and J.E. Sinsheimer (1981). Anal. Biochem., 115, 151.). Oxiranes, metabolites of 1-alkenes, were chosen as model electrophiles. The reagents (nicotinamide and cob(I)alamin) were evaluated in the determination of the rates of reaction toward valine methylamide, a model of N-terminal valines in hemoglobin often used for monitoring of doses in vivo of genotoxic carcinogens. The rate constants for reaction at 37°C with valine methylamide (k _VMA) determined by the cob(I)alamin and nicotinamide procedure, respectively, were for ethylene oxide (1.6, 1.7), propylene oxide (0.9, 1.1), 1,2-epoxybutane (0.7, 0.8) and 1,2-epoxyoctane (0.5, 0.6) M^?1?h^?1, decreasing with increasing number of carbons of the oxirane. Concentrations of oxiranes trapped with nicotinamide are underrated in reaction mixtures containing valine methylamide due to consumption by reaction with the competing nucleophile, a disturbance that is not observed in trapping with cob(I)alamin which reacts about 10⁵ times faster than nicotinamide. Cob(I)alamin which was demonstrated to be an efficient nucleophile for trapping of electrophiles, also in the presence of competing nucleophiles, is promising as an analytical tool in toxicological studies of reactive compounds. Furthermore, cob(I)alamin can be used to detect, measure and compare electrophilic reactivity of chemical substances, a property that is associated with genotoxic potency.     

On thermally forced flows in urban street canyons

During sunny days with periods of low synoptic wind, buoyancy forces can play a critical role on the air flow, and thus on the dispersion of pollutants in the built urban environments. Earlier studies provide evidence that when a surface inside an urban street canyon is at a higher temperature than that of local ambient air, buoyancy forces can modify the mechanically-induced circulation within the canyons (i.e., gaps between buildings). The aspect ratio of the urban canyon is a critical factor in the manifestation of the buoyancy parameter. In this paper, computational fluid dynamics simulations are performed on urban street canyons with six different aspect ratios, focusing on the special case where the leeward wall is at a greater temperature than local ambient air. A non-dimensional measure of the influence of buoyancy is used to predict demarcations between the flow regimes. Simulations are performed under a range of buoyancy conditions, including beyond those of previous studies. Observations from a field experiment and a wind tunnel experiment are used to validate the results.     

An Experiment with Forced Oxygenation of the Deepwater of the Anoxic By Fjord,Western Sweden

In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0524-9) contains supplementary material, which is available to authorized users.     

Decabromodiphenyl ethane and decabromodiphenyl ether in Swedish background air

Decabromodiphenyl ethane (DPDPE) is a flame retardant that has been on the market for more than 20 years and is used as a replacement for decabromodiphenyl ether (BDE-209). Environmental data on DPDPE are scarce but for BDE-209, studies have shown that long-range transport in the atmosphere leads to contamination of remote regions. Given their similar physical-chemical properties, we hypothesized that this is also true for DPDPE. In this study we explored the European continent as a source for DBDPE by collecting air samples at a back-ground location in southern Sweden. Twelve samples with stable air mass back trajectories over the 24 h sampling period were analysed. BDE-209 and 5 polycyclic aromatic hydrocarbons (PAHs) were also included in the study. The concentration ranges of DBDPE and BDE-209 were similar, 0.077-7.9 and 0.093-1.8 pg m⁻³ air, respectively. The highest concentrations were detected when the air originated from the European continent and the lowest during periods with rather stagnant air over southern Scandinavia. The concentrations of DBDPE and BDE-209 did not co-vary, indicating that there are different major sources of the two compounds. In air, the compounds measured in this study are predominantly associated with particles. PAHs in the atmosphere are known to originate primarily from combustion processes and their concentrations were highly correlated with several measures of atmospheric particle concentration, i.e. PM 10, PM 2.5, soot, and N 450 (number of particles in the size range approximately 420-450 nm). No clear correlations were found between the concentrations of DBDPE or BDE-209 and any of the measures of particle concentrations, indicating that the emissions of these are not related to the major sources of emissions of soot or small particles.     

与有机食品相关联的消费者行为的决定因素

对于消费者来说,在他们决定购买或消费有机食品(主要为新鲜的有机食品)时,哪些因素会影响他们的购物决定?学者们对这一问题的研究已经很多了.研究的结果均表明:人们的态度和实际的行为之间有一些矛盾,对于有机食品,人们往往态度上是积极的但是常常却不购买它们.这一矛盾主要源于消费者并不把"有机生产"当作一项重要的采购标准,另外,有机食品在口味及贮藏限期(食品的两种非常重要的品质)上也并不比常规的食品具有优越性.此外,有机食品在价格上被认为比常规食品明显偏贵也是一个重要的因素.根据两个瑞典实例研究发现,人们对有机食品的态度及行为与其健康收益具有非常紧密的关系,并且超过了其正面的环境影响.一个新的欧盟项目将对新鲜的以及加工的有机食品的影响进行调查,并且还将对八个欧盟国家的人们在选择有机食品时,道德、伦理及情感因素所产生的影响进行调查.     

Volatile metabolites from microorganisms grown on humid building materials and synthetic media

Growth of different microorganisms is often related to dampness in buildings. Both fungi and bacteria produce complicated mixtures of volatile organic compounds that include hydrocarbons, alcohols, ketones, sulfur- and nitrogen-containing compounds etc. Microbially produced substances are one possible explanation of odour problems and negative health effects in buildings affected by microbial growth. A mixture of five fungi, Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi were grown on three different humid building materials (pinewood, particle board and gypsum board) and on one synthetic medium. Six different sampling methods were used, to be able to collect both non-reactive volatile organic compounds and reactive compounds such as volatile amines, aldehydes and carboxylic acids. Analysis was performed using gas chromatography, high-performance liquid chromatography and ion chromatography, mass spectrometry was used for identification of compounds. The main microbially produced metabolites found on pinewood were ketones (e.g. 2-heptanone) and alcohols (e.g. 2-methyl-1-propanol). Some of these compounds were also found on particle board, gypsum board and the synthetic medium, but there were more differences than similarities between the materials. For example, dimethoxymethane and 1,3,5-trioxepane and some nitrogen containing compounds were found only on particle board. The metabolite production on gypsum board was very low, although some terpenes (e.g. 3-carene) could be identified as fungal metabolites. On all materials, except gypsum board, the emission of aldehydes decreased during microbial growth. No low molecular weight carboxylic acids were identified.