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A generating function method was used to simulate the vibrationally resolved absorption and emission spectra of perylene, terrylene and quaterrylene. This method operates on the basis of adiabatic excitation energies and electronic ground and excited state vibrational frequencies. These parameters were calculated using density functional theory with the PBE0 functional for perylene and terrylene and with the BH-LYP functional for quaterrylene. The vertical excitation energies of the lower excited states were calculated using functionals with differing amounts of Hartree-Fock exchange. The optimal functional for each molecule was chosen by comparing these energies to literature excitation energies. Using this technique the calculated absorption spectra and the calculated emission spectrum of perylene were found to be in excellent agreement with the literature experimental spectra after introducing a shift and a scaling factor. The most prominent bands of the absorption spectra were assigned to their respective vibronic transitions.

The mycotoxin deoxynivalenol (DON), produced in wheat, barley and maize by Fusarium graminearum and Fusarium culmorum, is threatening the health of humans and animals. With its worldwide high incidence in food and feed, mitigation strategies are needed to detoxify DON, maintaining the nutritional value and palatability of decontaminated commodities. A promising technique is biological degradation, where microorganisms are used to biotransform mycotoxins into less toxic metabolites. In this study, bacterial enrichment cultures were screened for their DON detoxification potential, where DON and its potential derivatives were monitored. The residual phytotoxicity was determined through a bioassay using the aquatic plant Lemna minor L. Two bacterial enrichment cultures were found to biotransform DON into a still highly toxic metabolite for plants. Furthermore, a cytotoxic effect was observed on the cellular viability of intestinal porcine epithelial cells. Through liquid chromatography high-resolution mass spectrometry analysis, an unknown compound was detected, and tentatively characterized with a molecular weight of 30.0 Da (i.e., CH2O) higher than DON. Metabarcoding of the subsequently enriched bacterial communities revealed a shift towards the genera Sphingopyxis, Pseudoxanthomonas, Ochrobactrum and Pseudarthrobacter. This work describes the discovery of a novel bacterial DON-derived metabolite, toxic to plant and porcine cells.

In the aqueous phase, fine particulate matter can form reactive species (RS) that influence the aging, properties, and health effects of atmospheric aerosols. In this study, we explore the RS yields of aerosol samples from a remote forest (Hyytiälä, Finland) and polluted urban locations (Mainz, Germany; Beijing, China), and we relate the RS yields to different chemical constituents and reaction mechanisms. Ultra-high-resolution mass spectrometry was used to characterize organic aerosol composition, electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique was applied to determine the concentrations of ⚫OH, O2⚫-, and carbon- or oxygen-centered organic radicals, and a fluorometric assay was used to quantify H2O2. The aqueous H2O2-forming potential per mass unit of ambient PM2.5 (particle diameter < 2.5 µm) was roughly the same for all investigated samples, whereas the mass-specific yields of radicals were lower for sampling sites with higher concentrations of PM2.5. The abundances of water-soluble transition metals and aromatics in ambient PM2.5 were positively correlated with the relative fraction of ⚫OH and negatively correlated with the relative fraction of carbon-centered radicals. In contrast, highly oxygenated organic molecules (HOM) were positively correlated with the relative fraction of carbon-centered radicals and negatively correlated with the relative fraction of ⚫OH. Moreover, we found that the relative fractions of different types of radicals formed by ambient PM2.5 were comparable to surrogate mixtures comprising transition metal ions, organic hydroperoxide, H2O2, and humic or fulvic acids. The interplay of transition metal ions (e.g., iron and copper ions), highly oxidized organic molecules (e.g., hydroperoxides), and complexing or scavenging agents (e.g., humic or fulvic acids) leads to nonlinear concentration dependencies in aqueous-phase RS production. A strong dependence on chemical composition was also observed for the aqueous-phase radical yields of laboratory-generated secondary organic aerosols (SOA) from precursor mixtures of naphthalene and β-pinene. Our findings show how the composition of PM2.5 can influence the amount and nature of aqueous-phase RS, which may explain differences in the chemical reactivity and health effects of particulate matter in clean and polluted air.

In recent years, honeybees and bee products such as pollen and honey have been used as bioindicators for monitoring environmental pollution. Unfortunately, there are few studies about polychlorinated biphenyl (PCB) concentrations in honeybees and bee products from Turkey. Honeybee and pollen samples were taken between May and September 2017, and honey samples were taken between July and September 2017 at urban and semi-urban areas in Bursa (Turkey). PCB concentrations measured by gas chromatography-microelectron capture detector (GC-mu ECD) were found to be 135.46 +/- 6.53, 81.47 +/- 23.52, and 106.35 +/- 21.60 ng g(-1) dry weight (dw) for honeybee, pollen, and honey samples in the urban area, respectively; and 126.35 +/- 26.54, 67.57 +/- 27.34, and 118.88 +/- 55.28 ng g(-1) dw for honeybee, pollen, and honey samples in the semi-urban area, respectively. Pearson correlation was made between meteorological parameters and pollutant concentrations. According to the correlation results, a significant relationship was found between the pollen and honey results and the total cloudiness and temperature in the semi-urban area. The coefficient of divergence (COD) and Pearson correlation coefficient (PCC) methods were applied to determine the similarities and differences between the pollutant concentrations and sources of the two areas and the temporal variation. According to these two methods, PCB concentrations and emission sources in honeybee and pollen samples in urban and semi-urban areas were generally different in May and June, and similar in August and September.

Air pollution by particulate matter in China affects human health, the ecosystem and the climate. However, the chemical composition of particulate aerosol, especially of the organic fraction, is still not well understood. In this study, particulate aerosol samples with a diameter of ≤2.5 µm (PM2.5) were collected in January 2014 in three cities located in northeast, east and southeast China, namely Changchun, Shanghai and Guangzhou. Organic aerosol (OA) in the PM2.5 samples was analyzed by an ultrahigh-performance liquid chromatograph (UHPLC) coupled to a high-resolution Orbitrap mass spectrometer in both negative mode (ESI-) and positive mode electrospray ionization (ESI+). After non-target screening including the assignment of molecular formulas, the compounds were classified into five groups based on their elemental composition, i.e., CHO, CHON, CHN, CHOS and CHONS. The CHO, CHON and CHN groups present the dominant signal abundances of 81 %–99.7 % in the mass spectra and the majority of these compounds were assigned to mono- and polyaromatics, suggesting that anthropogenic emissions are a major source of urban OA in all three cities. However, the chemical characteristics of these compounds varied between the different cities. The degree of aromaticity and the number of polyaromatic compounds were substantially higher in samples from Changchun, which could be attributed to the large emissions from residential heating (i.e., coal combustion) during wintertime in northeast China. Moreover, the ESI- analysis showed higher H/C and O/C ratios for organic compounds in Shanghai and Guangzhou compared to samples from Changchun, indicating that OA undergoes more intense photochemical oxidation processes in lower-latitude regions of China and/or is affected to a larger degree by biogenic sources. The majority of sulfur-containing compounds (CHOS and CHONS) in all cities were assigned to aliphatic compounds with low degrees of unsaturation and aromaticity. Here again, samples from Shanghai and Guangzhou show a greater chemical similarity but differ largely from those from Changchun. It should be noted that the conclusions drawn in this study are mainly based on comparison of molecular formulas weighted by peak abundance and thus are associated with inherent uncertainties due to different ionization efficiencies for different organic species.

Profound biogeochemical responses of anoxic sediments to the fluctuation of dissolved oxygen (DO) concentration in overlaying water are often observed, despite oxygen having a limited permeability in sediments. This contradiction is indicative of previously unrecognized mechanism that bridges the oxic and anoxic sediment layers. Using sediments from an urban river suffering from long-term polycyclic aromatic hydrocarbons (PAHs) contamination, we analyzed the physicochemical and microbial responses to artificially elevated DO (eDO) in the overlying water over 9 weeks of incubation. Significant changes in key environmental parameters and microbial diversity were detected over the 0-6 cm sediment depth, along with accelerated degradation of PAHs, despite that eDO only increased the porewater DO in the millimeter subfacial layer. The dynamics of physicochemical and microbial properties coincided well with significantly increased presence of centimeter-long sulfide-oxidizing cable bacteria filaments under eDO, and were predominantly driven by cable bacteria metabolic activities. Phylogenetic ecological network analyses further revealed that eDO reinforced cable bacteria associated interspecific interactions with functional microorganisms such as sulfate reducers, PAHs degraders, and electroactive microbes, suggesting enhanced microbial syntrophy taking advantage of cable bacteria metabolism for the regeneration of SO42- and long-distance electron transfer. Together, our results suggest cable bacteria may mediate the impacts of eDO in anaerobic sediments by altering sediment physiochemical properties and by reinforcing community interactions. Our findings highlight the ecological importance of cable bacteria in sediments.

Superhydrogenated polycyclic aromatic hydrocarbons (PAHs) have been suggested to catalyze the formation of H2 in certain regions of space, but it remains unclear under which circumstances this mechanism is viable given the reduced carbon backbone stability of superhydrogenated PAHs. We report a laboratory study on the stability of the smallest pericondensed PAH, pyrene (C16H10+N , with N = 4, 6, and 16 additional H atoms), against photodestruction by single vacuum ultraviolet photons using the photoelectron–photoion coincidence technique. For N = 4, we observe a protective effect of hydrogenation against the loss of native hydrogens, in the form of an increase in the appearance energies of the and C16H8 + daughter ions compared to those reported for pristine pyrene (C16H10). No such effect is seen for N = 6 or 16, where the weakening effect of replacing aromatic bonds with aliphatic ones outweighs the buffering effect of the additional hydrogen atoms. The onset of fragmentation occurs at similar internal energies for N = 4 and 6, but is significantly lower for N = 16. In all three cases, H-loss and C m H n -loss (m ≥ 1, carbon backbone fragmentation) channels open at approximately the same energy. The branching fractions of the primary channels favor H-loss for N = 4, C m H n -loss for N = 16, and are roughly equal for the intermediate N = 6. We conclude that superhydrogenated pyrene is probably too small to support catalytic H2-formation, while trends in the current and previously reported data suggest that larger PAHs may serve as catalysts up to a certain level of hydrogenation.

WOS:000604141800013; International audience; Accidental spills are pervasive pollution in aquatic ecosystems. Resorting to chemical dispersant is one of the most implemented strategies in response to oil spills, but it results in an increase in the bio-availability of oil compounds known to disturb fish neurosensory capacities and hence fish habitat use. While it has become well established that acute oil exposure can cause a range of physiological defects, sub-lethal consequences on animal behaviour have only received recent attention. Here we investigated the effect of an exposure to a 62 h-dispersant treated oil on the exploration tendency (exploratory activity, and avoidance of unfamiliar open areas) of juvenile European sea bass. Three different concentrations of chemically dispersed oil were tested, low and medium conditions bracketing the range of likely situations that fish encounter following an oil spill, the high dose representing a more severe condition. Fish recovery capacities were also evaluated during 2 weeks post-exposure. Our results suggest a dose-response relationship; the low dose (0.048 +/- 0.007 g L-1 of total petroleum hydrocarbons ([TPH])) had no effect on sea bass behavioural response to a novel environment while medium (0.243 +/- 0.012 g L-1 [TPH]) and high (0.902 +/- 0.031 g L-1 [TPH]) doses altered fish exploratory activity and their typical avoidance of unfamiliar open areas. Our experiment also suggest signs of recovery capacities in the first 10 days following oil exposure even if fish might need more time to fully recover from observed alterations. We discuss the possibility that observed alterations may result from a neurosensory or physiological known defects of oil exposure, causing anaesthetic-like sedative behaviours. Altogether, this study shows that juvenile sea bass exposed to oil spill exhibit transient behavioural impairments that may have major population-level consequences given the high mortality experienced by juveniles.

Background: Exposure to polycyclic aromatic hydrocarbons (PAHs) is linked to abnormal lipid metabolism, but evidence regarding PAHs as risk factors for dyslipidemia is lacking.Objective: To investigate the respective role and interaction of PAH exposure and antioxidant consumption in the risk for pediatric dyslipidemia.Methods: We measured the concentrations of serum lipids, superoxide dismutase (SOD) and urinary hydroxylated PAHs (OH-PAHs) in 403 children, of which 203 were from an e-waste-exposed area (Guiyu) and 200 were from a reference area (Haojiang). Biological interactions were calculated by additive models.Results: Guiyu children had higher serum triglyceride concentration and dyslipidemia incidence, and lower serum concentration of high-density lipoprotein (HDL) than Haojiang children. Elevated OH-PAH concentration, and concomitant SOD reduction, were both associated with lower HDL concentration and higher hypo-HDL risk (S3OH-Phes: B for lgHDL = 0.048, P Conclusion: High PAH exposure combined with SOD reduction is recommended for predicting elevated risk for pediatric dyslipidemia. Risk assessment of PAH-related dyslipidemia should take antioxidant concentration into consideration.

We investigated the effects of two California wildfires (Rocky and Wragg Fires, 2015) compared to an unburned reference watershed on water quality, dissolved organic matter (DOM), and precursors of disinfection by-products (DBPs) for two years' post-fire. The two burned watersheds both experienced wildfires but differed in the proportion of burned watershed areas. Burned watersheds showed rapid water quality degradation from elevated levels of turbidity, color, and suspended solids, with greater degradation in the more extensively burned watershed. During the first year's initial flushes, concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), ammonium (NH4+/NH3), and specific ultraviolet absorbance (SUVA(254)) were significantly higher (67 +/- 40%, 418 +/- 125%, 192 +/- 120%, and 31 +/- 17%, respectively) in the more extensively burned watershed compared to the reference watershed. These elevated values gradually declined and finally returned to levels like the reference watershed in the second year. Nitrate concentrations were near detection limits (0.01 mg-N/L) in the first year but showed a large increase in fire-impacted streams during the second rainy season, possibly due to delayed nitrification. Changes in DOM composition, especially during the initial storm events, indicated that fires can attenuate humic-like and soluble microbial by-product-like (SMP) DOM while increasing the proportion of fulvic-like, tryptophan-like, and tyrosine-like compounds. Elevated bromide (Br-) concentrations (up to 8.7 mu M]) caused a shift in speciation of trihalomethanes (THMs) and haloacetic acids (HAAs) to brominated species for extended periods (up to 2 years). Wildfire also resulted in elevated concentrations of N-nitrosodimethylamine (NDMA) precursors. Such changes in THM, HAA, and NDMA precursors following wildfires pose a potential treatability challenge for drinking water treatment, but the effects are relatively short-term (

Molecular hydrogen (H2) is the main constituent of the gas in the planet-forming disks that surround many PMS stars. H2 can be incorporated in the atmosphere of the giant planets. HD has been detected in a few disks and can be considered the most reliable tracer of H2. We wish to form H2 and HD efficiently for the varied conditions encountered in protoplanetary disks: the densities vary from 1E4 to 1E16 cm^-3; the dust temperatures range from 5 to 1500 K, the gas temperatures go from 5 to a few 1000 Kelvin, and the ultraviolet field can be 1E7 stronger than the standard interstellar field. We implemented a comprehensive model of H2 and HD formation on cold and warm grain surfaces and via hydrogenated PAHs in the physico-chemical code ProDiMo. The H2 and HD formation can proceed via the Langmuir-Hinshelwood and Eley-Ridel mechanisms for physisorbed or chemisorbed H (D) atoms. H2 and HD also form by H (D) abstraction from hydrogenated neutral and ionised PAHs and via gas phase reactions. H2 and HD are formed efficiently on dust grain surfaces from 10 to 700 K. All the deuterium is converted into HD in UV shielded regions as soon as H2 is formed by gas-phase D abstraction reactions. The detailed model compares well with standard analytical prescriptions for H2 (HD) formation. At low temperatures, H2 is formed from the encounter of two physisorbed atoms. HD molecules form on the grain surfaces and in the gas-phase. At temperatures greater than 20 K, the meeting between a weakly bound H- (or D-) atom or a gas-phase H (D) atom and a chemisorbed atom is the most efficient H2 formation route. H2 formation through hydrogenated PAHs alone is efficient above 80 K. The contribution of hydrogenated PAHs to the overall H2 and HD formation is relatively low if chemisorption on silicate is taken into account and if a small hydrogen abstraction cross-section is used., Comment: 26 pages, accepted to A&A

The aim of the present study was to investigate effects of defined mixtures of polycyclic aromatic hydrocarbons (PAHs) and perfluoroalkyl substances (PFASs), at low, environmentally relevant (1× = L), or high (20× = H) doses, on biological responses in Atlantic cod (Gadus morhua). To this end, farmed juvenile cod were exposed at day 0 and day 7 via intraperitoneal (i.p.) injections, in a two-week in vivo experiment. In total, there were 10 groups of fish (n = 21-22): two control groups, four separate exposure groups of PAH and PFAS mixtures (L, H), and four groups combining PAH and PFAS mixtures (L/L, H/L, L/H, H/H). Body burden analyses confirmed a dose-dependent accumulation of PFASs in cod liver and PAH metabolites in bile. The hepatosomatic index (HSI) was significantly reduced for three of the combined PAH/PFAS exposure groups (L-PAH/H-PFAS, H-PAH/L-PFAS, H-PAH/H-PFAS). Analysis of the hepatic proteome identified that pathways related to lipid degradation were significantly affected by PFAS exposure, including upregulation of enzymes in fatty acid degradation pathways, such as fatty acid β-oxidation. The increased abundances of enzymes in lipid catabolic pathways paralleled with decreasing levels of triacylglycerols (TGs) in the H-PFAS exposure group, suggest that PFAS increase lipid catabolism in Atlantic cod. Markers of oxidative stress, including catalase and glutathione S-transferase activities were also induced by PFAS exposure. Only minor and non-significant differences between exposure groups and control were found for cyp1a and acox1 gene expressions, vitellogenin concentrations in plasma, Cyp1a protein synthesis and DNA fragmentation. In summary, our combined proteomics and lipidomics analyses indicate that PFAS may disrupt lipid homeostasis in Atlantic cod., This study was funded by Research Council of Norway through the dCod 1.0: decoding the systems toxicology of Atlantic cod project (Center for Digital Life Norway project no. 248840) and the iCod 2.0: Integrative environmental genomics of Atlantic cod project(project no. 244564). The authors wish to thank Frederike Keitel-Gröner for contributing to sampling, and Essa Ashan Khan for contributing to sampling and manuscript information. We also thank Hui-Shan Tung and Pål Olsvik for contributing to liver RT-qPCR preparation and analysis at the Institute of Marine Research (IMR). We further thank Inge Jonassen and Ketil Hylland for valuable input proteomics analysis, and on experiment and manuscript design, respectively.

The stepwise solvation of various cationic coronene oligomers bypara-hydrogen (p-H-2) molecules was computationally investigated using a united-atom model for thep-H(2)molecules and the Silvera-Goldman potential, together with a polarizable description for the interaction with the hydrocarbon molecules. A survey of the energy landscape for oligomers containing between 1 and 4 coronene molecules and possible different conformers was carried out using standard global optimization, the hydrocarbon complex being kept as rigid. The most stable structures provided the starting configuration of systematic path-integral molecular dynamics simulations at 2 K. The variations of the geometric and energetic properties of the solvation shell were determined with increasing number ofpara-hydrogen molecules. The relative stability of the solvation shell is generally found to be more robustly determined by the energy increment (or dissociation energy) than by geometrical indicators, especially when the oligomers have less ordered structures. In agreement with recent mass spectrometry experiments, the size at which the first solvation shell is complete is found to vary approximately linearly with the oligomer size when the coronene molecules stack together, with a slope that is related to the offset between two successive molecules., NA

Lack of suitable electron donors or acceptors is in many cases the key reason for pollutants to persist in the environment. Externally supplementation of electron donors or acceptors is often difficult to control and/or involves chemical additions with limited lifespan, residue formation or other adverse side effects. Microbial electrochemistry has evolved very fast in the past years - this field relates to the study of electrochemical interactions between microorganisms and solid-state electron donors or acceptors. Current can be supplied in such so-called bioelectrochemical systems (BESs) at low voltage to provide or extract electrons in a very precise manner. A plethora of metabolisms can be linked to electrical current now, from metals reductions to denitrification and dechlorination. In this perspective, we provide an overview of the emerging applications of BES and derived technologies towards the bioremediation field and outline how this approach can be game changing This work was funded through the European Union’s Horizon 2020project ELECTRA under grant agreement No. 826244 and National Natural Science Foundation of China (NSFC) (No. 31861133001,31861133002, 31861133003). S.P is a Serra Húnter Fellow (UdG-AG-575) and acknowledges the funding from the ICREA Acad emia award.LEQUiA has been recognized as consolidated research group by theCatalan Government with code 2017-SGR-1552. KR is supported by theGhent University special research fund under grant No. BOF19/GOA/026

The current study quantifies the impact of equivalence ratio and rate of strain on the spatial distribution of major species and soot precursors in premixed turbulent ethylene flames crossing the soot inception limit. A back-to-burnt (BTB) opposed jet configuration is used to provide accurate control of the turbulent and chemical timescales. The upper nozzle features fractal grid generated turbulence and premixed ethylene/air mixtures with flames stabilised against well-defined hot combustion products emerging from the lower nozzle. The study combines simultaneous PAH/CH 2 OPLIF and elastic light scattering (ELS) with probe sampling. Gas chromatography-mass spectrometry (GCMS) and gas chromatography-thermal conductivity detector (GC–TCD) were used to quantify concentrations of major species and poly-aromatic hydrocarbons (PAHs). The laser based diagnostics show that the rate of strain exerts a dominant impact on the growth of soot particles with low turbulent Reynolds numbers ( 50 ≤ R e t ≤ 94 ) used to promote soot formation. The probe measurements indicate that acetylene, 1-methylnaphthalene (1–MN), m/z = 154, m/z = 276 and benzo(a)pyrene correlate with soot formation and that the equivalence ratio is the controlling PAH growth parameter. It is further shown that the spatial extent of the PAH containing reaction zone exceeds three integral length scales.

In this work, we studied the control of Listeria monocytogenes in raw chicken meat by marinating breast strips with beer containing bacteriocin leucocin C. An URA3 auxotrophic strain of probiotic yeast Saccharomyces boulardii CNCM I-745 was used as a host to express the gene lecC encoding the bacteriocin leucocin C. Secretion of leucocin C was confirmed by the inhibition against L. monocytogenes using agar well diffusion assay. The new auxotrophic host secreted leucocin C better than previously constructed wild-type strain, and therefore it was used to brew anti-listerial beer. The beer was shown to maintain its anti-listerial activity for 38 days. Chicken breast strips spiked with L. monocytogenes were then marinated with the anti-listerial beer for overnight, and the killing of L. monocytogenes was analysed. Marination with beer containing leucocin C reduced the viable cells of L. monocytogenes by about 1.6 log from (2.2 +/- 0.6) x 10(7) CFU/g on day 24, and 2.2 log from (1.8 +/- 0.3) x 10(5) CFU/g on day 38. In conclusion, the URA3 auxotrophic S. boulardii efficiently secreted the bacteriocin leucocin C, and brewing beer with this strain resulted in anti-listerial beer. Such beer is effective as a marinade in reducing the Listeria risk in chicken breast strips.

The effect of multiple stressors on marine ecosystems is poorly understood. To partially bridge this knowledge gap we investigated the relative contribution of environmental variables to density and diversity dynamics of the zooplankton community in the Belgian part of the North Sea. We applied multimodel inference on generalized additive models to quantify the relative contribution of chlorophyll a, temperature, nutrients, salinity and anthropogenic chemicals (i.e. polychlorinated biphenyls and polycyclic aromatic hydrocarbons) to the dynamics of calanoid copepod species in the Belgian part of the North Sea. Temperature was the only predictor consistently showing a high importance in all models predicting the abundances of the selected copepod species. The relative contribution of other predictors was species-dependent. Anthropogenic chemicals were important predictors for three out of six species indicating that chemical mixtures at low concentrations should not be left unattended when performing risk assessments in a natural environment.

Solid phase microextraction (SPME) is a versatile, non-exhaustive sample preparation tool that has been demonstrated to be well-suited for facile and effective analysis of a broad range of compounds in a plethora of studies. A growing number of reports describing diverse SPME workflows for novel investigations in a variety of fields, such as flavor and fragrance investigations, environmental studies, and diverse bioanalytical applications, among others, corroborate the applicability of this microextraction tool in the analytical sciences

Exposure to benzo[a]pyrene (B[a]P) is known to play a role in lung carcinogenesis and the underlying processes can be modified by the presence of inflammation. The inflammatory process can for instance enhance the concentration of reactive metabolites that bind to DNA and may also diminish DNA repair. Additionally, during the inflammatory process mediators are released that create a microenvironment which is suitable for further stimulation of cancer development. Various transcriptional pathways are activated by inflammation, including pathways that are mediated via nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B), signal transducer and activator of transcription 3 (STAT-3), and hypoxia-inducible factor-1 (HIF-1). Crosstalk between these pathways and the aryl hydrocarbon receptor (AhR) occurs at multiple levels and thereby boosts B[a]P induced carcinogenesis. This review focuses on inflammatory mediators, including cytokines, chemokines and extracellular enzymes that modulate molecular events in B[a]P induced cancers.

Extraterrestrial organic matter has been widely studied; however, its response to pressure has not. Primitive organic matter bearing meteorites, such as CI and CM carbonaceous chondrites, have experienced variable pressures, up to 10 GPa. To appreciate the effects of these pressures on the organic content of these bodies, the model compounds isophthalic acid, vanillin and vanillic acid were subjected to pressures of up to 11.5 GPa and subsequently decompressed. High resolution synchrotron source Fourier Transform Infrared (FTIR) was used to determine the effects of different benzene substituents at high pressure on both the vibrational assignments of the benzene core of the molecules and the ability of the aromatic compounds to form intermolecular hydrogen bonds. The presence of additional peaks at high pressure was found to coincide with molecules that contain carboxyl groups, these features are interpreted as C-H---O intermolecular hydrogen bonds. The formation of these hydrogen bonds has implications for the origination of macromolecular organic matter (MOM), owing to the importance of such attractive forces during episodes of cross linking, such as esterification. Pressure-induced hydrogen bond formation is a process by which aromatic MOM precursors could have cross linked to generate the organic polymers found within extraterrestrial bodies today.

Hydrophobic hydrocarbons are absorbed by cell membranes. The effects of hydrocarbons on biological membranes have been studied extensively, but less is known how these compounds affect lipid phase separation. Here, we show that pyrene and pyrene-like hydrocarbons can dissipate lipid domains in phase separating giant unilamellar vesicles at room temperature. In contrast, related aromatic compounds left the phase separation intact, even at high concentration. We hypothesize that this behavior is because pyrene and related compounds lack preference for either the liquid-ordered (Lo) or liquid-disordered (Ld) phase, while larger molecules prefer Lo, and smaller, less hydrophobic molecules prefer Ld. In addition, our data suggest that localization in the bilayer (depth) and the shape of the molecules might contribute to the effects of the aromatic compounds. Localization and shape of pyrene and related compounds are similar to cholesterol and therefore these molecules could behave as such.

This study documents the effects of igneous dike intrusion on organic geochemical parameters of a shallow marine originated, Late Jurassic black shale (av. TOC = 2.2 wt%) in the Kutch rift basin in western India. The dike intrusion forms extremely to mildly altered, meter-scale zones around them. The primary wrinkled micro texture of the shale is lost completely, and organic matter is charcoalized in the extremely altered zone recording a Rock-Eval T-max > 458 degrees C. Immature type-III kerogen dominating the unaltered shale records abundant coniferal biomarkers such as retene, ent-beyerane, phyllocladane, ent-kaurane, abietane, labdane and norisopimarane, besides n-alkanes, hopanes and steranes. The transition from the unaltered (Rock-Eval T-max < 432 C) to the altered zone involves a decrease in carbon preference index (CPI), pristane/n-C-17, phytane/n-C-18, C-30 hopane/C-29 alpha alpha alpha-sterane and gradual increase in C-29 diasterane/sterane, trisnorneohopane/trisnorhopane (Ts/Tm), Ts/C-30 hopane, C-29/C-30 hopane and C-29 20S/(20S + 20R) sterane ratios. Although most saturate biomarkers disappear in the extremely altered zone, it records a high abundance of thermogenic polycyclic aromatic hydrocarbons (PAHs), commonly found in palaeo-fire deposits. Besides the PAH ratios, methylphenanthrene index-1, pristane/phytane, CPI and C-29/C-30 hopane ratios are found to be influenced significantly by thermal maturation in the extremely altered zone. The fluoranthene/(fluoranthene + pyrene) ratio correctly distinguishes different intensities of combustion products, while other PAH ratios behave differently at the immediate contact of the dike. Pr/Ph ratio may correctly interpret the redox condition up to a Rock-Eval T-max similar to 520 degrees C, while it is ineffective at high maturity. The results of the investigation are significant for the assessment of stability of biomarkers in highly matured source rocks, recording potential redox-sensitive biomarkers in highly matured shales and detection of palaeo-fire deposits in ancient sedimentary succession.

In this study, we collected Polychlorinated biphenyls (PCBs) using passive air samplers (PASs), between February 4, 2013 and February 2, 2014, with the sampling periods ranging from 10 to 60days. The samples were collected with PASs that contained polyurethane foam (PUF). With these samples, 87 PCB congeners were analyzed. Sampling coefficient (R) values for the four seasons were calculated using both the high volume air sampler (HVAS) and PAS samples collected with the same time interval. The average of the annual concentrations of 87 PCB congeners, calculated using the R values specific to this study, was 234 +/- 175pg/m(3). PCB congeners with 3- and 4- chlorines were dominant. The samples were collected at the same time interval but at different times to represent accumulation in the PASs. The linear regression coefficients (r) of the PCB mass accumulated in PASs against time ranged from 0.89 and 0.97 indicating that accumulation was linear. Moreover, the concentrations of the PCB congeners were statistically correlated with atmospheric conditions.

Even though emission inventories indicate that wood combustion is a major source of polycyclic aromatic hydrocarbons (PAHs), estimating its impacts on PAH concentration in ambient air remains challenging. In this study the effect of local small-scale wood combustion on the benzo[a]pyrene (BaP) concentrations in ambient air in the Helsinki metropolitan area in Finland is evaluated, using ambient air measurements, emission estimates, and dispersion modeling. The measurements were conducted at 12 different locations during the period from 2007 to 2015. The spatial distributions of annual average BaP concentrations originating from wood combustion were predicted for four of those years: 2008, 2011, 2013, and 2014. According to both the measurements and the dispersion modeling, the European Union target value for the annual average BaP concentrations (1 ng m−3) was clearly exceeded in certain suburban detached-house areas. However, in most of the other urban areas, including the center of Helsinki, the concentrations were below the target value. The measured BaP concentrations highly correlated with the measured levoglucosan concentrations in the suburban detached-house areas. In street canyons, the measured concentrations of BaP were at the same level as those in the urban background, clearly lower than those in suburban detached-house areas. The predicted annual average concentrations matched with the measured concentrations fairly well. Both the measurements and the modeling clearly indicated that wood combustion was the main local source of ambient air BaP in the Helsinki metropolitan area.

PAHs are one of the important components of the carbonaceous matter of the Universe. They are not detected in the darkest regions of the Interstellar Medium and one possible reason could be their chemical transformation through gas phase reactions In particular, their oxidation was considered ineffective because the reaction barriers appear to be too high, based on combustion studies conducted at high temperatures. For the first time, we experimentally studied the oxidation of Coronene, a PAH archetype, at low temperature (50 K), as well as the oxidation of hydrogenated Coronenes. It appears that reactivity is higher than expected and that the fragmentation of coronene is a significant channel of the oxidation. Furthermore, hydrogenated coronenes are very reactive to oxygen. To understand the experimental data, DFT calculations were performed. They confirm a low oxidation barrier (0.11 eV) and show that oxygen is preferentially inserted at the periphery of the coronene and propose a reaction mechanism for fragmentation also involving a hydrogen atom. An estimate of the orders of magnitude shows that PAH oxidation may explain part of the decrease in their abundances in warm environments.

The freshwater flagellate alga Euglena agilis Carter was exposed to the polycyclic aromatic hydrocarbon (PAH) anthracene for 96 h under optimal photosynthetically active radiation (PAR), and responses of growth, photosynthetic pigment production, and photosynthetic efficiency were assessed. Anthracene reduced the growth rate (μ) and levels of chlorophyll a (Chl a), chlorophyll b (Chl b), and total carotenoids. The growth rate was more sensitive than photosynthetic parameters, with a median effective concentration (EC50) of 4.28 mg L−1. Between 5 and 15 mg L−1, anthracene inhibited the maximum quantum yield (Fv/Fm) of photosystem II (PSII) and the maximum photosynthetic electron transport rate through PSII (rETRmax) with EC50 values of 14.88 and 11.8 mg L−1, respectively. At all anthracene concentrations, intracellular reactive oxygen species (ROS) were elevated, indicating increased oxidative stress. Anthracene presumably reduced the PSII efficiency of photochemical energy regulation and altered the photochemistry through intracellular ROS formation. Acute exposure to PAHs may induce severe physiological changes in phytoplankton cells, which may influence vital ecological processes within the aquatic environments. Additionally, growth and Chl a content may serve as sensitive risk assessment parameters of anthracene toxicity in water management since EC50 values for both overlap with anthracene levels (8.3 mg L−1) permitted by the US Environmental Protection Agency (USEPA).

Oxidative potential (OP), which is the ability of certain components in atmospheric particles to generate reactive oxidative species (ROS) and deplete antioxidants in vivo, is a prevailing toxicological mechanism underlying the adverse health effects associated with exposure to ambient aerosols. While previous studies have identified the high OP of fresh biomass burning organic aerosols (BBOA), it remains unclear how it evolves throughout atmospheric transport. Using the dithiothreitol (DTT) assay as a measure of OP, a combination of field observations and laboratory experiments is used to determine how atmospheric aging transforms the intrinsic OP (OPmassDTT) of BBOA. For ambient BBOA collected during the fire seasons in Greece, OPmassDTT was observed to increase by a factor of 2.1 +/- 0.9 for samples of atmospheric ages up to 68 h. Laboratory experiments indicate that aqueous photochemical aging (aging by UVB and UVA photolysis; as well as 01-1 oxidation), as well as aging by ozone and atmospheric dilution can transform the OPmassDTT of the water-soluble fraction of wood smoke within 2 days of atmospheric transport. The results from this work suggest that the air quality impacts of biomass burning emissions can extend beyond regions near fire sites and should be accounted for.

VUV photons from a synchrotron source were used to record the gas-phase absorption spectrum of isoquinoline over the range 3.5 to 10.7 eV. The rich spectrum exhibits both broad and sharp features, of varying intensities, that are analyzed into eight valence and eight Rydberg transitions. Previous data on the valence transitions of isoquinoline were essentially limited to solution spectra up to 5.4 eV. Our study increases their number considerably. The features in the 3.96 eV region are discussed in terms of vibronic coupling between the nπ∗ 1 1 A′′ and ππ∗ 2 1 A′ valence electronic states. The intensities of some spectral features are augmented by collective π-electron modes considered to be of plasmon-type. Assignments of the valence transitions were facilitated by our DFT calculations and by earlier Pariser-Parr-Pople MO calculations. The calculation results are compared and their relative value is discussed. The DFT calculations reproduce very well a number of experimentally determined properties of the ground state of isoquinoline, in particular its bond distances and angles, rotational constants, vibrational frequencies and dipole moment. No Rydberg series of isoquinoline have previously been observed. Three of the newly observed Rydberg series converge to the D 0 electronic ground state of the ion, while two converge to the D 1 and three to the D 3 excited electronic states of the cation. Astrophysical applications of the VUV absorption spectrum of isoquinoline, in particular the measured absorption cross-sections, are briefly discussed. A comparison between the absorption spectra of isoquinoline and quinoline highlights their similarities and differences, related to their respective molecular orbitals.

Background: The increased incidence of diseases, including metabolic syndrome and infertility, may be related to exposure to the mixture of chemicals, which are ubiquitous in the modern environment (environmental chemicals, ECs). Xeno-detoxification occurs within the liver which is also the source of many plasma proteins and growth factors and plays an important role in the regulation of homeostasis. Objectives: The objective of this study was to investigate the effects of ECs on aspects of liver function, in a well characterized ovine model of exposure to a real-life EC mixture. Methods: Four groups of sheep (n = 10–12/sex/treatment) were maintained long-term on control or sewage sludge-fertilized pastures: from conception to culling at 19 months of age in females and from conception to 7 months of age and thereafter in control plots until culling at 19 months of age in males. Environmental chemicals were measured in sheep livers and RNA and protein extracts were assessed for exposure markers. Liver proteins were resolved using 2D differential in-gel electrophoresis and differentially expressed protein spots were identified by liquid chromatography/tandem mass spectroscopy. Results: Higher levels of polycyclic aromatic hydrocarbons (PAHs) and lower levels of polychlorinated biphenyls (PCBs) in the livers of control males compared to control females indicated sexually dimorphic EC body burdens. Increased levels of the PAHs Benzo[a]anthracene and chrysene and reduced levels of PCB 153 and PCB 180 were observed in the livers of continuously exposed females. EC exposure affected xenobiotic and detoxification responses and the liver proteome in both sexes and included major plasma-secreted and blood proteins, and metabolic enzymes whose pathway analysis predicted dysregulation of cancer-related pathways and altered lipid dynamics. The latter were confirmed by a reduction in total lipids in female livers and up-regulation of cancer-related transcript markers in male livers respectively by sewage sludge exposure. Conclusions: Our results demonstrate that chronic exposure to ECs causes major physiological changes in the liver, likely to affect multiple systems in the body and which may predispose individuals to increased disease risks. Keywords: Environmental exposure, PAH, Sewage sludge, Sheep, Liver, Proteomics

We present the first vacuum ultraviolet spectroscopic study of an interstellar ice analogue of a 1:100 benzene (C 6 H 6 ):carbon dioxide (CO 2 ) mixture which has been energetically processed with 1 keV electrons. We have exploited the fact that benzene has a relatively high photoabsorption cross section in the vacuum ultraviolet region to study this dilute mixture of benzene. Before irradiation with 1 keV electrons, we observed that the benzene electronic transition bands in the C 6 H 6 :CO 2 mixture exhibits a blueshift in band position towards energies observed in the gas-phase compared with that of pure, amorphous benzene and we have attributed this to a matrix isolation effect. After irradiation, a lowering in intensity of both the carbon dioxide and benzene electronic transition bands was observed, as well as the formation of the small irradiation product, carbon monoxide. A residue was obtained at 200 K which showed characteristic features of the benzene electronic transition of 1 E 1u ← 1 A 1g , but with additional structure suggesting the formation of a benzene derivative.

Wildfires are increasing in prevalence and intensity and emit large quantities of persistent organic and inorganic pollutants. Recent fires have caused elevated concerns that residual pollutants in indoor environments pose a long‐term health hazard to residents, however, to date no studies have investigated how long fire‐derived pollutants are retained in indoor environments. We quantified polycyclic aromatic hydrocarbons (PAHs) and toxic trace elements in ground ashes from the 2016 wildland‐urban interface fires in Fort McMurray (Alberta, Canada) and in house dust from 64 homes. We document residual arsenic pollution from local building fires, but found no evidence that forest fire ash remained in households 14 months after the fire. Overall, house dust pollutant concentrations were equal or lower than in other locations unaffected by wildfires. Given the current and future concerns over wildfire impacts, this study provides importance evidence on the degree of their long‐term effects on the residential environment.

Polychlorinated biphenyls (PCBs) were measured in ambient air samples (n = 48) that were collected for a 2- to 3-day period in each season (winter, spring, summer, fall) of 2013. The samples were collected on the Campus of Uludag University, which is in a semirural region. The samples were collected using a high-volume air sampler. The gas and particle phase concentrations of 87 PCB congeners (I 87PCB) pound were measured in these samples. The average gas and particle phase concentrations of the I 87PCB pound were calculated to be 293 +/- 257 and 52 +/- 56 ng/m(3), respectively. However, the results of short-term measurements showed that the variation among the measurements in the gas phase was up to 39-fold and up to 84-fold in the particle phase. These results demonstrated that the ambient air PCB concentrations were not stable and changed dramatically on a daily basis. Therefore, it was clear that a small number of samples could not be representative of the entire region. Furthermore, the obtained concentrations showed differences that depended on the meteorological conditions and long distance transportation. The sampling indicated that PCB homologues with 3 or 4 chlorines were dominant.

Photoelectron spectroscopy is usually described by a simple equation that relates the binding energy of the photoemitted electron, E-binding, its kinetic energy, E-kinetic, the energy of the ionizing photon, E-photon, and the work function of the spectrometer, phi, E-binding = E-photon - E-kinetic - phi. Behind this equation there is an extremely rich physics, which we describe here using as an example a relatively simple conjugated molecule, namely coronene. The theoretical analysis of valence band and C1s core level photoemission spectra showed that multiple excitations play an important role in determining the intensities of the final spectrum. An explicit, time-evolving model is applied, which is able to count all possible photo-excitations occurring during the photoemission process, showing that they evolve on a short time-scale, of about 10 fs. The method reveals itself to be a valid approach to reproduce photoemission spectra of polycyclic aromatic hydrocarbons (PAHs).

Bu çalışma, 2015 tarihlerinde Caparica[Portekiz]’ da düzenlenen 1. International Caparica Conference on Pollutant Toxic Ions and Molecules (PTIM) Kongresi‘nde bildiri olarak sunulmuştur. Wet deposition fluxes of organochlorine pesticides (OCPs) were determined for rain samples collected in a coastal area of Turkey. Seventeen precipitation samples were collected over a 1-year period from 2008 to 2009. Rainwater was accumulated at the beginning of rain events using real time monitoring. Atmospheric concentrations were also measured in parallel with deposition samples. Both atmospheric concentrations and deposition fluxes were determined as particle and gas phases. The particle phase and dissolved phase deposition fluxes were 794.26 +/- 756.70 ngm(-2) day(-1) and 800.77 +/- 672.63 ngm(-2) day(-1), respectively. The washout ratios for OCP compounds were calculated separately for the particle and dissolved phases using the atmospheric concentrations and rain concentrations. The minimum washout ratio for the particle phase was 2339.47 for Endrin aldehyde, whereas the maximum washout ratio was 497593.34 for Methoxychlor. The maximum washout ratio for the dissolved phase was 247523.89 for Endosulfan beta, whereas the minimum washout ratio was 10169.69 for p,p'-DDT. The dry deposition velocities ranged from 0.01 to 1.67 cms(-1). The partitioning of wet deposition between the particle and dissolved phases was 50 % in terms of total OCP deposition.

This study was to investigate the levels of heavy metals in PM2.5 and in blood, the prevalence of respiratory symptoms and asthma, and the related factors to them. Lead and cadmium in both PM2.5 and blood were significant higher in Guiyu (exposed area) than Haojiang (reference area) (p 5 mu g/dL was significantly associated with asthma (OR, 9.50; 95% CI, 1.16-77.49). Higher blood chromium and blood manganese were associated with more cough and wheeze, respectively. Our data suggest that living in e-waste exposed area may lead to increased levels of heavy metals, and accelerated prevalence of respiratory symptoms and asthma. (C) 2016 Elsevier Ltd. All rights reserved.

Pseudomonas aeruginosa is an efficient pyrene degrader that can utilize pyrene through induction of high cell surface hydrophobicity. The effect of three surfactants, Triton X-100, Tween 80 and rhamnolipid JBR 515 on rate and extent of pyrene (100 mg l(-1)) degradation was evaluated through batch studies. Among the three surfactants Triton X-100 demonstrated highest pyrene solubilization. All surfactants were used at 10 times the critical micelle concentration (CMC) so as to ensure notable enhancement in solubilization. However, growth of P. aeruginosa on pyrene and pyrene degradation was inhibited in the presence of Triton X-100 possibly due to accumulation of toxic metabolites formed due to partial utilization of Triton X-100. Tween 80 supported higher rate of pyrene degradation due to higher biomass generation during simultaneous utilization of pyrene and Tween 80 as carbon source. In presence of rhamnolipid JBR 515 preferential degradation of surfactant over pyrene resulted in decrease in specific growth rate and pyrene utilization rate. Maximum biodegradation rates (MBR) for pyrene were 0.458, 1.111 and 0.154 mg l(-1) h(-1) in absence of any surfactant, in presence of Tween 80 and rhamnolipid JBR 515, respectively. The results suggest that Tween 80 is the preferred surfactant for remediation of pyrene using P. aeruginosa RS1 strain. (C) 2015 Elsevier Ltd. All rights reserved.

Chemical composition and bioreactivity of PM2.5 samples collected from Beijing (BJ), Xi'an (XA), Xiamen (XM) and Hong Kong (HK) in China during haze events were characterized. PM2.5 mass concentrations in BJ, XA, XM and HK in the episodes were found to be 258 ± 100 μg m−3, 233 ± 52 μg m−3, 46 ± 9 μg m−3 and 48 ± 13 μg m−3, respectively. Significant increase of sulfate, nitrate and ammonium concentrations in northern cities were observed. High contributions of biomass burning emissions to organic carbon (OC) in northern cities were estimated in this study implying frequent biomass burning during the haze periods. The urea concentrations in PM2.5 were 1855 ± 755 ng m−3 (BJ), 1124 ± 243 ng m−3 (XA), 543 ± 104 ng m−3 (XM) and 363 ± 61 ng m−3 (HK) suggesting higher or close to upper limits compared to other regions in the world. Dose-dependent alterations in oxidative potential, IL-6, IFN-γ and TNF-α levels were also investigated. The oxidative potential levels are BJ > XM > XA > HK, whereas levels of IL-6, IFN-γ and TNF-α were BJ > XA > XM > HK. The sulfate, nitrate, ammonium, OC, urea and levoglucosan are associated with oxidative-inflammatory responses. These experimental results are crucial for the policymakers to implement cost-effective abatement strategies for improving air quality.

Aromatic compounds are characterised by the presence of a ring current when in a magnetic field. As a consequence, current density maps are used to assess (the degree of) aromaticity of a compound. However, often a more discrete set of so-called Nucleus Independent Chemical Shift (NICS) values is used that is derived from the current density. It is shown here that there is no simple one-to-one relationship that allows reconstructing current density maps from only NICS-values. NICS values should therefore not be used as aromaticity indices without analysis of the ab initio computed current density map.

Place: Amsterdam Publisher: Elsevier WOS:000537410700010; Copepods are excellent bioindicators of climate change and ecosystem pollution in anthropized coastal waters. This work reviewed the results of previous studies examining changes in egg production rate (EPR), hatching success (HS), and nauplius survival rate (NSR) in natural conditions and in the presence of pollutants, including heavy metals and organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants (POPs). At high concentrations, cadmium and silver induce an increase in EPR in the copepods Acartia tonsa and Acartia hudsonica, while exposure to mercury decreases EPR in adults by 50%. All three metals affect HS, with mercury inducing a stronger effect than cadmium and silver. Cadmium affects reproductive traits in Centropages ponticus, decreasing EPR and particularly HS. Furthermore, copper and chromium at high concentrations induce significant decreases in eggs per female in Notodiaptomus conifer. In terms of organic contaminant and Polycyclic Aromatic Hydrocarbons (PAHs), Eurytemora affinis is reported to be affected by naphthalene, 2-methylnaphthalene, 2,6-dimethylnaphthalene, and 2,3,5-trimethylnaphthalene and can thus be used in ecotoxicity studies, but only if the exposure time is high. Acartia tonsa shows significant reductions in EPR and HS at high concentrations of fluoranthene, phenanthrene, and pyrene. However, the response to Persistent Organic Pollutants (POPs) such as pentachlorophenol (PCP) and 1,2-dichlorobenzene (DCB) differs. In E. affinis, EPR increases with DCB, but HS falls to \textless1%. EPR increases when the species is exposed overnight, but HS remains low in the presence of DCB. Based on these results, we developed a novel copepod reproductive trait index (CRT-Index) for use in marine ecotoxicology surveys and tested in some simple cases. We show that copepods are good candidates as models for ecotoxicology studies, in particular using reproductive traits (EPR, HS and NSR) because of their sensitivity to a wide range or pollutants. (C) 2020 Elsevier B.V. All rights reserved.

Bioremediation offers a sustainable approach for removal of polycyclic aromatic hydrocarbons (PAHs) from the environment; however, information regarding the microbial communities involved remains limited. In this study, microbial community dynamics and the abundance of the key gene (PAH-RHDa) encoding a ring hydroxylating dioxygenase involved in PAH degradation were examined during degradation of phenanthrene in a podzolic soil from the site of a former timber treatment facility. The 10,000-fold greater abundance of this gene associated with Gram-positive bacteria found in phenanthrene-amended soil compared to unamended soil indicated the likely role of Gram-positive bacteria in PAH degradation. In contrast, the abundance of the Gram-negative PAHs-RHDa gene was very low throughout the experiment. While phenanthrene induced increases in the abundance of a small number of OTUs from the Actinomycetales and Sphingomonadale, most of the remainder of the community remained stable. A single unclassified OTU from the Micrococcaceae family increased similar to 20-fold in relative abundance, reaching 32% of the total sequences in amended microcosms on day 7 of the experiment. The relative abundance of this same OTU increased 4.5-fold in unamended soils, and a similar pattern was observed for the second most abundant PAH-responsive OTU, classified into the Sphingomonas genus. Furthermore, the relative abundance of both of these OTUs decreased substantially between days 7 and 17 in the phenanthrene-amended and control microcosms. This suggests that their opportunistic phenotype, in addition to likely PAH-degrading ability, was determinant in the vigorous growth of dominant PAH-responsive OTUs following phenanthrene amendment. This study provides new information on the temporal response of soil microbial communities to the presence and degradation of a significant environmental pollutant, and as such has the potential to inform the design of PAH bioremediation protocols. This work was funded under the Irish Environmental Protection Agency STRIVE programme 2007–2013 (grant no. 2008-PhD-WRM-1), the Ireland-Wales Programme 2007-2013 (GIFT project), and the SLAB scholarship programme of the Malaysian Ministry of Higher Education and the International Islamic University, Malaysia. peer-reviewed

We present experimental data on H2 formation processes on gas-phase polycyclic aromatic hydrocarbon (PAH) cations. This process was studied by exposing coronene radical cations, confined in a radio-frequency ion trap, to gas phase H atoms. Sequential attachment of up to 23 hydrogen atoms has been observed. Exposure to atomic D instead of H allows one to distinguish attachment from competing abstraction reactions, as the latter now leave a unique fingerprint in the measured mass spectra. Modeling of the experimental results using realistic cross sections and barriers for attachment and abstraction yield a 1:2 ratio of abstraction to attachment cross sections. The strong contribution of abstraction indicates that H2 formation on interstellar PAH cations is an order of magnitude more relevant than previously thought., Comment: 8 pages, 4 figures, accepted to MNRAS

Organic geochemistry of Gondwana coals, especially the distribution of molecular fossils or biomarkers, is not well constrained, throughout the world. In this study, we have, therefore, evaluated biomarker signatures along with bulk organic matter and petrographic characteristics in coal samples collected from two Gondwana Basins in India – Satpura Basin (Kanhan coalfield) and Damodar Valley Basin (Jharia coalfield). From both coalfields, the samples were collected from the Lower Permian Barakar Formation, which is one of the major coal bearing strata in India. A significant variation in thermal maturity levels in the samples is indicated by Rock-Eval pyrolysis and petrographic analysis–with the Kanhan samples generally belonging to immature to early-mature stage, while the Jharia samples display characteristics of overmature coals. This variation in the thermal maturity strongly affects the biomarker distributions. Especially, the terpenoids, hopanes and steranes were considerably degraded due to thermal maturation and were below detection limit in the overmature samples. Presence of aliphatic diterpanes, ent-16α(H)-kaurane, 16α(H)-phyllocladane as well as aromatic diterpanes, retene, methylretenes, tetrahydroretene, simonellite and bisnorsimonellite in low maturity samples indicate terrestrial input, possibly, from the primitive conifers. However, the aliphatic and aromatic diterpanes were below detection limit in overmature samples making it difficult to infer their source. Distributions of polycyclic aromatic hydrocarbons (PAHs) are also controlled by thermal maturity levels, as evident from difference in PAH ratios in the low and high maturity samples.

An ongoing discussion revolves around the question of what effect hydrogenation has on carbon backbone fragmentation in Polycyclic Aromatic Hydrocarbons (PAHs). In order to shed more light on this issue, we have measured absolute single carbon loss cross sections in collisions between native or hydrogenated pyrene cations (C$_{16}$H$_{10+m}^{+}, m$ = 0, 6, 16) and He as functions of center-of-mass energies all the way down to 20 eV. Classical Molecular Dynamics (MD) simulations give further insight into energy transfer processes and also yield $m$-dependent threshold energies for prompt (femtoseconds) carbon knockout. Such fast, non-statistical fragmentation processes dominate CH$_x$-loss for native pyrene ($m=0$), while much slower statistical fragmentation processes contribute significantly to single-carbon loss for the hydrogenated molecules ($m=6$ and $m=16$). The latter is shown by measurements of large CH$_x$-loss cross sections far below the MD knockout thresholds for C$_{16}$H$_{16}^{+}$ and C$_{16}$H$_{26}^{+}$., 7 pages, 6 figures

Genotoxic carcinogens significantly damage cells and tissues by targeting macromolecules such as proteins and DNA, but their mechanisms of action and effects on human health are diverse. Consequently, determining the amount of exposure to a carcinogen and its cellular effects is essential, yet difficult. The aim of this manuscript was to investigate the potential of detecting alterations in volatile organic compounds (VOCs) profiles in the in vitro headspace of pulmonary cells after exposure to the genotoxic carcinogens cisplatin and benzo[a] pyrene using two different sampling setups. A prototypeset-up was used for the cisplatin exposure, whereas a modified set-up was utilized for the benzo[a] pyrene exposure. Both carcinogens were added to the cell medium for 24 h. The headspace in the culture flask was sampled to measure theVOCcontent using gas chromatographytime- of-flight-mass spectrometry. Eight cisplatin-specific VOCs and six benzo[a] pyrene-specific VOCs were discriminatory between treated and non-treated cells. Since the in vivo biological effects of both genotoxic compounds are well-defined, the origin of the identified VOCs could potentially be traced back to common cellular processes including cell cycle pathways, DNAdamage and repair. These results indicate that exposing lung cells to genotoxins alters headspaceVOCprofiles, suggesting that it might be possible to monitorVOCchanges in vivo to study drug efficacy or exposure to different pollutants. In conclusion, this study emphasizes the innovative potential of in vitro VOCs experiments to determine their in vivo applicability and discover their endogenous origin.

Background Polycyclic aromatic hydrocarbons (PAHs) accumulate in urban soils, and PAH contamination can change soil microbial community composition. Environmental microbiota is associated with human commensal microbiota, immune system and health. Therefore, studies investigating the degradation of PAHs, and the consequences of soil pollution on microbial communities in urban landscaping materials, are crucial. Methods Four landscaping materials (organic matter 1, 2, 13 and 56%) were contaminated with PAHs commonly found at urban sites (phenanthrene, fluoranthene, pyrene, chrysene and benzo(b)fluoranthene) in PAH concentrations that reflect urban soils in Finland (2.4 µg g -1 soil dry weight). PAHs were analyzed initially and after 2, 4, 8 and 12 weeks by gas chromatography-mass spectrometry. Half-lives of PAHs were determined based on 12-weeks degradation. Bacterial communities were analyzed at 1 and 12 weeks after contamination using Illumina MiSeq 16S rRNA gene metabarcoding. Results Half-lives ranged from 1.5 to 4.4 weeks for PAHs with relatively low molecular weights (phenanthrene, fluoranthene and pyrene) in landscaping materials containing 1–2% organic matter. In contrast, in materials containing 13% and 56% organic matter, the half-lives ranged from 2.5 to 52 weeks. Shorter half-lives of phenanthrene and fluoranthene were thus associated with low organic matter content. The half-life of pyrene was inversely related to the relative abundance of Beta-, Delta- and Gammaproteobacteria, and diversity of Bacteroidetes and Betaprotebacteria. Compounds with higher molecular weights followed compound-specific patterns. Benzo(b)fluoranthene was resistant to degradation and half-life of chrysene was shorter when the relative abundance of Betaproteobacteria was high. Temporal microbiota changes involved increase in the relative abundance of Deltaproteobacteria and decrease in genera Flavobacterium and Rhodanobacter. Exposure to PAHs seems to adjust microbial community composition, particularly within class Beta- and Deltaproteobacteria. Conclusions In this study, PAH degradation depended on the organic matter content and bacterial community composition of landscaping materials. Contamination seems to alter bacterial community composition in landscaping materials depending on material type. This alteration includes changes in bacterial phyla associated with human health and immune system. This may open new possibilities for managing urban environments by careful selection of landscaping materials, to benefit health and wellbeing.

The use of biochar (BC) has been suggested for remediation of contaminated soils. This study aims to investigate the role of microorganisms in sorption of PAH to BC-amended soils. Fungi, especially the wood and litter-degrading fungi, have shown the ability for humification and to degrade recalcitrant molecules, and are thus suitable model organisms. Haplic Arenosol with high organic matter content was chosen to highlight the importance of soil organic matter (SOM) in PAH sorption, possibly to form non-extractable residue. Basidiomycetous fungi Agrocybe praecox and Phanerochaete velutina grown on pine bark were inoculated in organic matter (OM)-rich Haplic Arenosol and OM-poor sandy loam with either BC or chemically activated BC (ABC) and 14C-labelled pyrene for 60 days. Fungi did not mineralize pyrene, but increased sorption up to 47–56% in BC-amended Haplic Arenosol in comparison with controls (13–25%) without a fungus irrespective of the presence of an adsorbent. In OM-poor sandy loam, only 9–12% of pyrene was sorbed to amended soil in the presence of fungus and adsorbent. The results suggest that BC and fungal amendment increased sorption of pyrene, especially to Haplic Arenosol more than by either BC or fungi alone.

The challenges of simulating extreme ultraviolet (XUV)-induced dissociation dynamics of organic molecules on a multitude of coupled potential energy surfaces are discussed for the prototypical photoionization of benzene. The prospects of Koopmans' theorem-based electronic structure calculations in combination with classical trajectories and Tully's fewest switches surface hopping are explored. It is found that a Koopmans' theorem-based approach overestimates the CH dissociation barrier and thus underestimates the fragmentation yield. However, the nonadiabatic population dynamics are in good agreement with previous approaches, indicating that the Koopmans' theorem based potentials are well described around the Franck-Condon point. This is explicitly tested for the ground state potential of the benzene cation employing CASPT2 calculations, for which very good agreement is found. This work highlights the need for efficient electronic structure approaches that can treat medium-sized organic molecules with a multitude of coupled excited states and several dissociation channels.

Conjugation through space can give rise to aromaticity in the lowest excited triplet state, with impact for photochemistry., Cyclic conjugation that occurs through-space and leads to aromatic properties is called homoaromaticity. Here we formulate the homoaromaticity concept for the triplet excited state (T1) based on Baird's 4n rule and validate it through extensive quantum-chemical calculations on a range of different species (neutral, cationic and anionic). By comparison to well-known ground state homoaromatic molecules we reveal that five of the investigated compounds show strong T1 homoaromaticity, four show weak homoaromaticity and two are non-aromatic. Two of the compounds have previously been identified as excited state intermediates in photochemical reactions and our calculations indicate that they are also homoaromatic in the first singlet excited state. Homoaromaticity should therefore have broad implications in photochemistry. We further demonstrate this by computational design of a photomechanical “lever” that is powered by relief of homoantiaromatic destabilization in the first singlet excited state.

Excessive acid rainfall associated with emplacement of the Siberian Traps magmatic province is increasingly accepted as a major contributing factor to the end-Permian biosphere crisis. However, direct proxy evidence of terrestrial acidification is so far not available. In this paper, we seek to determine the probability that relative proportions of extractable monophe- nolic components from soil-derived organic matter in marine sediments provide a molecular proxy for estimating soil acidity. Intermittently low and high ratios of vanillic acid to vanillin detected in latest Permian and earliest Triassic deposits of the southern Alps, Italy, support concepts of pulses of severe acidification (pH

Absorption, distribution, metabolism and excretion (ADME) of food-borne toxic compounds may be influenced by other compounds or constituents present in the food. The present review presents an overview of evidence currently available on food matrix-derived combination effects influencing the ADME characteristics of food-borne toxic compounds and the possible implications for risk assessment. The results obtained indicate that interactions may occur at all levels of ADME and that the interactions may decrease but also increase the bioavailability and/or toxicity of the compounds of interest. The overview also illustrates that food matrix-derived combination effects should be considered on a case-by-case basis, taking into account especially the mode of action underlying the interactions and the dose dependency of the effects. Especially food matrix-derived combination effects that proceed by a reversible mode of action, such as for example binding to biotransformation enzymes or transport proteins, may be detected at concentrations used in in vitro assays and at dose levels used in animal bioassays but may be absent at dose levels representing realistic human intake. It is concluded that although food matrix-derived combination effects may exist, their detection in in vitro assays or in animal bioassays at high dose levels may not improve risk assessment practice because interactions observed may not be maintained at low realistic levels of intake. Insight in the mode of action underlying the interactions combined with physiologically based kinetic (PBK) modelling may prove a way to obtain better insight in whether interactions detected at high dose levels will still be relevant at more realistic lower intake levels, and thus to what extent these effects should be taken into account in the risk assessment for human exposure.