Organophosphate Esters in Building Materials from China: Levels, Sources, Emissions, and Preliminary Assessment of Human Exposure.

Source characteristics and health risks of indoor organophosphate esters (OPEs) are limited by the lack of knowledge on emission processes. This study attempted to integrate the contents and emissions of OPEs from indoor building materials to assess human health effects. Thirteen OPEs were investigated in 80 pieces of six categories of building materials. OPEs are ubiquitous in the building materials and ∑13OPE contents varied significantly (p < 0.05) from 72.8 ng/g (seam agent) to 109,900 ng/g (wallpaper). Emission characteristics of OPEs from the building materials were examined based on a microchamber method. Depending on the sample category, the observed initial area-specific emission rates of ∑13OPEs varied from 154 ng/m2/h (carpet) to 2760 ng/m2/h (wooden floorboard). Moreover, the emission rate model was developed to predict the release levels of individual OPEs, quantify source contributions, and assess associated exposure risks. Source apportionments of indoor OPEs exhibited heterogeneities in multiple environmental media. The joint OPE contribution of wallpaper and wooden floorboard to indoor dust was up to 94.8%, while latex paint and wooden floorboard were the main OPE contributors to indoor air (54.2%) and surface (76.1%), respectively. Risk assessment showed that the carcinogenic risks of tris(2-chloroethyl) phosphate (3.35 × 10-7) were close to the acceptable level (1 × 10-6) and deserved special attention.

Efficient acid hydrolysis for compound-specific δ15N analysis of amino acids for determining trophic positions.

Compound-specific isotope analysis of nitrogen in amino acids (CSIA-AA, δ15NAA) has gained increasing popularity for elucidating energy flow within food chains and determining the trophic positions of various organisms. However, there is a lack of research on the impact of hydrolysis conditions, such as HCl concentration and hydrolysis time, on δ15NAA analysis in biota samples. In this study, we investigated two HCl concentrations (6 M and 12 M) and four hydrolysis times (2 h, 6 h, 12 h, and 24 h) for hydrolyzing and derivatizing AAs in reference materials (Tuna) and biological samples of little egret (n = 4), night heron (n = 4), sharpbelly (n = 4) and Algae (n = 1) using the n-pivaloyl-iso-propyl (NPIP) ester approach. A Dowex cation exchange resin was used to purify amino acids before derivatization. We then determined δ15NAA values using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The results revealed no significant differences (p > 0.05) in δ15NAA values among samples treated with different HCl concentrations or hydrolysis times, particularly for δ15NGlx (range: 21.0-23.5‰) and δ15NPhe (range: 4.3-5.4‰) in Tuna (12 M). Trophic positions (TPs) calculated based on δ15NAA at 2 h (little egret: 2.9 ± 0.1, night heron: 2.8 ± 0.1, sharpbelly: 2.0 ± 0.1 and Algae: 1.3 ± 0.2) were consistent with those at 24 h (3.1 ± 0.1, 2.8 ± 0.1, 2.2 ± 0.1 and 1.1 ± 0.1, respectively), suggesting that a 2-h hydrolysis time and a 6 M HCl concentration are efficient pretreatment conditions for determining δ15NAA and estimating TP. Compared to the currently used hydrolysis conditions (24 h, 6 M), the proposed conditions (2 h, 6 M) accelerated the δ15NAA assay, making it faster, more convenient, and more efficient. Further research is needed to simplify the operational processes and reduce the time costs, enabling more efficient applications of CSIA-AA.

Using live videography observation and Bayesian isotope mixing model to identify food composition and dietary contribution to inorganic mercury and methylmercury intake by songbird nestlings.

Mercury (Hg) exposure is increasing in terrestrial birds; however, studies on its sources are scarce. In the present study, we elucidated the food composition of green-backed tit nestlings from three urban forest parks (CPL, AHL, and LCG) using live videography observation (LVO). Furthermore, the daily dietary intakes of inorganic Hg (IHg) (MDIIHg) and methylmercury (MeHg) (MDIMeHg) were determined using the Bayesian isotope mixing model (BIMM) to uncover the nestlings' specific dietary Hg contribution. Both LVO and BIMM indicated that Lepidoptera (primarily caterpillar) constituted the primary food source for the nestlings in the three forests, accounting for approximately 60% of their diet in all three forest parks. The estimated MDI of Hg revealed that lepidopterans and spiders primarily contributed to IHg exposure, with a co-contribution ratio of 71.8%-97.7%. Unexpectedly, dietary MeHg was mostly derived from spiders; the highest contribution ratio of 93.6% was recorded at CPL, followed by another peak ratio of 92.9% at LCG. However, the dietary exposure was primarily IHg, accounting for 69.8% (AHL), 62.0% (LCG), and 61.3% (CPL) of the nestlings. Our study findings highlight the importance of dietary IHg transfer in evaluating the effects of Hg in nestlings. LVO, coupled with BIMM, is an effective tool for determining the food compositions of songbird nestlings and estimating the contribution of specific diets.

[Research progress of traditional Chinese medicine intervention for ulcerative colitis based on Notch1 signaling pathway].

Ulcerative colitis(UC) is one of the common gastrointestinal diseases worldwide. In recent years, the incidence of UC has been continuously increasing, seriously threatening the health of people globally. It thus has become an urgent problem that needs to be addressed. There is research evidence that intestinal mucosal barrier dysfunction, including changes in intestinal stem cell secretion lineage, mucosal layer damage, disruption of cell junctions, overactive immune function, and imbalanced gut microbiota, is an important pathogenic factor and molecular basis of UC. The Notch signaling pathway is a highly conserved signaling pathway in eukaryotes during evolution, which transmits signals through cell connections between adjacent cells, affecting a series of processes such as cell proliferation, differentiation, development, migration, and apoptosis. Therefore, the Notch signaling pathway can regulate intestinal stem cells, CD4~+T cells, innate lymphoid cells(ILCs), macrophages(MØ), and intestinal microbiota and thus affect the chemical, physical, immune, and biological mucosal barriers of the intestinal mucosa. Its function is extensive and unique, different from those signaling pathways that mainly focus on anti-inflammatory and antioxidant stress. It can explain the therapeutic effects of traditional Chinese medicine from different perspectives. This article reviewed the role of the Notch1 signaling pathway in the pathogenesis of UC and the relevant literature on the targeted prevention and treatment of UC with traditional Chinese medicine, so as to provide new targets and theoretical support for further research on the effective prevention and treatment of UC.

Efficient and Selective Adsorption of Cationic Dye Malachite Green by Kiwi-Peel-Based Biosorbents.

In this study, pristine kiwi peel (KP) and nitric acid modified kiwi peel (NA-KP) based adsorbents were prepared and evaluated for selective removal of cationic dye. The morphology and chemical structure of KP and NA-KP were fully characterized and compared, and results showed nitric acid modification introduced more functional groups. Moreover, the adsorption kinetics and isotherms of malachite green (MG) by KP and NA-KP were investigated and discussed. The results showed that the adsorption process of MG onto KP followed a pseudo-second-order kinetic model and the Langmuir isotherm model, while the adsorption process of MG onto NA-KP followed a pseudo-first-order kinetic model and the Freundlich isotherm model. Notably, the Langmuir maximum adsorption capacity of NA-KP was 580.61 mg g-1, which was superior to that of KP (297.15 mg g-1). Furthermore, thermodynamic studies demonstrated the feasible, spontaneous, and endothermic nature of the adsorption process of MG by NA-KP. Importantly, NA-KP showed superior selectivity to KP towards cationic dye MG against anionic dye methyl orange (MO). When the molar ratio of MG/MO was 1:1, the separation factor (αMG/MO) of NA-KP was 698.10, which was 5.93 times of KP. In addition, hydrogen bonding, π-π interactions, and electrostatic interaction played important roles during the MG adsorption process by NA-KP. This work provided a low-cost, eco-friendly, and efficient option for the selective removal of cationic dye from dyeing wastewater.

Characterizing Key Volatile Pollutants Emitted from Adhesives by Chemical Compositions, Odor Contributions and Health Risks.

As one of the major sources of volatile pollutants in indoor air, gaseous emissions from adhesives during interior decoration have attracted increasing concern. Identifying major volatile pollutants and the risk in adhesive gaseous emissions is of great significance, but remains rarely reported. In the present research, we assessed the major volatile pollutants emitted from white emulsion adhesive and silicone adhesive samples (n = 30) from three aspects: chemical composition, odor and health risk contributions. The results showed that a total of 21 volatile pollutants were detected. Significantly, xylene was the most concentrated compound from white emulsion adhesives, accounting for 45.51% of the total concentrations. Butanone oxime was the most concentrated compound in silicone adhesives, accounting for 69.86% of the total concentrations. The trends in odor concentration (evaluated by the odor activity value method) over time were well correlated with the total chemical concentrations. Xylene (58.00%) and butanone oxime (76.75%) showed the highest odor contribution, respectively. Moreover, from an integrated perspective of chemical emissions, odor and health risk contributions, xylene, ethylbenzene, ethyl acetate and benzene were identified as the key volatile pollutants emitted from the white emulsion adhesives, while butanone oxime, butanone, and ethanol were the key volatile pollutants emitted from the silicone adhesives. This study not only identified the key volatile pollutants but also provided characteristics of odor and health risks of gas emitted from adhesives.

Visual Analysis of Odor Interaction Based on Support Vector Regression Method.

The complex odor interaction between odorants makes it difficult to predict the odor intensity of their mixtures. The analysis method is currently one of the factors limiting our understanding of the odor interaction laws. We used a support vector regression algorithm to establish odor intensity prediction models for binary esters, aldehydes, and aromatic hydrocarbon mixtures, respectively. The prediction accuracy to both training samples and test samples demonstrated the high prediction capacity of the support vector regression model. Then the optimized model was used to generate extra odor data by predicting the odor intensity of more simulated samples with various mixing ratios and concentration levels. Based on these olfactory measured and model predicted data, the odor interaction was analyzed in the form of contour maps. This intuitive method showed more details about the odor interaction pattern in the binary mixture. We found that that the antagonism effect was commonly observed in these binary mixtures and the interaction degree was more intense when the components' mixing ratio was close. Meanwhile, the odor intensity level of the odor mixture barely influenced the interaction degree. The machine learning algorithms were considered promising tools in odor researches.

A Hybrid Spectrum Access Strategy with Channel Bonding and Classified Secondary User Mechanism in Multichannel Cognitive Radio Networks.

Cognitive radio networks (CRNs) can improve spectrum utilization by allowing secondary users (SUs) to dynamically access channels unoccupied by primary users (PUs). The spectrum access strategy, as a point to enhance user performance, has received much attention. In this paper, we propose a hybrid access mode for network users in multichannel CRNs. For meeting different SU demands, SUs are classified as SU1s and SU2s. We further introduce a channel bonding scheme for high-priority (PU and SU1) user packets to enhance transmission efficiency. At the same time, we propose a hybrid spectrum access strategy for SU2 packets to improve their transmission stability. By establishing a Markov chain model, some important SU2 packets' performance measures are derived. Furthermore, we display the comparison of hybrid, overlay and underlay modes by numerical results to analyze the advantages of different modes.

Anti-inflammatory effects and mechanisms of vagal nerve stimulation combined with electroacupuncture in a rodent model of TNBS-induced colitis.

The purpose of this study was to determine the effects and mechanisms of vagal nerve stimulation (VNS) and additive effects of electroacupuncture (EA) on colonic inflammation in a rodent model of IBD. Chronic inflammation in rats was induced by intrarectal TNBS (2,4,6-trinitrobenzenesulfonic acid). The rats were then treated with sham ES (electrical stimulation), VNS, or VNS + EA for 3 wk. Inflammatory responses were assessed by disease activity index (DAI), macroscopic scores and histological scores of colonic tissues, plasma levels of TNFα, IL-1ß, and IL-6, and myeloperoxidase (MPO) activity of colonic tissues. The autonomic function was assessed by the spectral analysis of heart rate variability (HRV) derived from the electrocardiogram. It was found that 1) the area under curve (AUC) of DAI was substantially decreased with VNS + EA and VNS, with VNS + EA being more effective than VNS (P < 0.001); 2) the macroscopic score was 6.43 ± 0.61 in the sham ES group and reduced to 1.86 ± 0.26 with VNS (P < 0.001) and 1.29 ± 0.18 with VNS + EA (P < 0.001); 3) the histological score was 4.05 ± 0.58 in the sham ES group and reduced to 1.93 ± 0.37 with VNS (P < 0.001) and 1.36 ± 0.20 with VNS + EA (P < 0.001); 4) the plasma levels of TNFα, IL-1ß, IL-6, and MPO were all significantly decreased with VNS and VNS + EA compared with the sham ES group; and 5) autonomically, both VNS + EA and VNS substantially increased vagal activity and decreased sympathetic activity compared with sham EA (P < 0.001, P < 0.001, respectively). In conclusion, chronic VNS improves inflammation in TNBS-treated rats by inhibiting proinflammatory cytokines via the autonomic mechanism. Addition of noninvasive EA to VNS may enhance the anti-inflammatory effect of VNS.NEW & NOTEWORTHY This is the first study to address and compare the effects of vagal nerve stimulation (VNS), electrical acupuncture (EA) and VNS + EA on TNBS (2,4,6-trinitrobenzenesulfonic acid)-induced colitis in rats. The proposed chronic VNS + EA, VNS, and EA were shown to decrease DAI and ameliorate macroscopic and microscopic damages in rats with TNBS-induced colitis via the autonomic pathway. The addition of EA to VNS provided a significant effect on the behavioral assessment of inflammation (DAI, CMDI, and histological score) but not on cytokines or mechanistic measurements, suggesting an overall systemic effect of EA.View this article's corresponding video summary at https://youtu.be/-rEz6HMkErM.

The Regular Interaction Pattern among Odorants of the Same Type and Its Application in Odor Intensity Assessment.

The olfactory evaluation function (e.g., odor intensity rating) of e-nose is always one of the most challenging issues in researches about odor pollution monitoring. But odor is normally produced by a set of stimuli, and odor interactions among constituents significantly influenced their mixture's odor intensity. This study investigated the odor interaction principle in odor mixtures of aldehydes and esters, respectively. Then, a modified vector model (MVM) was proposed and it successfully demonstrated the similarity of the odor interaction pattern among odorants of the same type. Based on the regular interaction pattern, unlike a determined empirical model only fit for a specific odor mixture in conventional approaches, the MVM distinctly simplified the odor intensity prediction of odor mixtures. Furthermore, the MVM also provided a way of directly converting constituents' chemical concentrations to their mixture's odor intensity. By combining the MVM with usual data-processing algorithm of e-nose, a new e-nose system was established for an odor intensity rating. Compared with instrumental analysis and human assessor, it exhibited accuracy well in both quantitative analysis (Pearson correlation coefficient was 0.999 for individual aldehydes (n = 12), 0.996 for their binary mixtures (n = 36) and 0.990 for their ternary mixtures (n = 60)) and odor intensity assessment (Pearson correlation coefficient was 0.980 for individual aldehydes (n = 15), 0.973 for their binary mixtures (n = 24), and 0.888 for their ternary mixtures (n = 25)). Thus, the observed regular interaction pattern is considered an important foundation for accelerating extensive application of olfactory evaluation in odor pollution monitoring.

Electrical neuromodulation at acupoint ST36 normalizes impaired colonic motility induced by rectal distension in dogs.

Electroacupuncture (EA) has been shown to improve impaired gastric motility and slow waves in both humans and animals. However, its effects on colonic motility have rarely been investigated. The aim of this study was to investigate the effects and underlying mechanisms of EA on impaired colonic motility induced by rectal distension (RD)in dogs. Colon contractions and transit were measured in various sessions with and without EA in hound dogs chronically placed with a colonic cannula. Colonic contractile activity was assessed by motility index (MI). Autonomic functions were determined by the spectral analysis of the heart rate variability derived from the electrocardiogram. It was found 1) RD suppressed colonic motility by 40.5% (10.8 ± 0.9 with RD vs. 6.4 ± 0.8 at baseline, P < 0.002). EA at ST36 normalized colonic contractions suppressed by RD (12.9 ± 2.8, P < 0.002 vs. RD and P = 0.1 vs. control). 2) Administration of atropine blocked the ameliorating effect of EA on colon motility. 3) RD also delayed colonic transit (65.0 ± 2.0% with RD vs. 86.0 ± 1.9% without RD, P < 0.001) that was restored with EA (84.0 ± 1.9%, P = 0.178 vs. control). 4) EA increased vagal activity suppressed by RD (0.37 ± 0.07 with RD + EA vs. 0.09 ± 0.03 with RD without EA, P < 0.001). In conclusion, RD inhibits colonic contractions and delays colonic transit in dogs; EA at ST36 restores the RD-induced impairment in both colonic contraction and transit by enhancing vagal activity and mediated via the cholinergic pathway.

Determination of organophosphate esters in water samples by mixed-mode liquid chromatography and tandem mass spectrometry.

A simple and sensitive method for the determination of organophosphate esters in water samples by mixed-mode liquid chromatography with electrospray ionization tandem mass spectrometry coupled with solid-phase extraction is developed. Using seven alkyl phosphates, three chlorinated alkyl phosphates, and four aryl phosphates as the targets, the developed method was systematically evaluated on the basis of the influence of the solid-phase extraction cartridge, eluting solvent, sample-loading volume, mobile phase condition, and the separation of reversed-phase chromatography and mixed-mode liquid chromatography. Under the optimal conditions, these organophosphate esters can be extracted by ENVI-18 cartridge, eluted by 6 mL of 25% dichloromethane in acetonitrile, and then qualified and quantified by mixed-mode liquid chromatography with tandem mass spectrometry in the multiple reaction-monitoring mode. The application of mixed-mode liquid chromatography endows the separation with reasonable retention for both hydrophilic and hydrophobic organophosphate esters regardless of their polarity, which is hardly achieved by reversed-phase chromatography. Good linearity (from 0.9877 to 0.9969), low quantification limits (1-35 ng/L after extraction of 100 mL of river water), and acceptable recovery rates (58.6-116.2%, with the relative standard deviation <18.0%) were obtained. Finally, the established method was used for analyzing surface water samples, and the good applicability of this method was demonstrated.

Graphene-supported CoPc/TiO2synthesized by sol-gel-hydrothermal method with enhanced photocatalytic activity for degradation of the typical gas of landfill exhaust.

This work was focused on the enhanced photocatalytic activity of cobalt phthalocyanine (CoPc)/TiO2under visible light irradiation supported on reduced graphene oxide (RGO). A series of RGO/CoPc/TiO2nanocomposites were synthesized via sol-gel-hydrothermal method. The photocatalysts were characterized by X-ray diffraction, BET surface area, Scanning electron microscopy, Raman spectra, Fourier transform infrared spectra, UV-Vis spectra and Photoluminescence spectra. The results demonstrated that the TiO2existed as anatase phase both of CoPc/TiO2and RGO/CoPc/TiO2composites, and the absorption range in visible light of RGO/CoPc/TiO2composites were broadened further. The photodegradation results of diethyl sulfide, the typical gas of landfill exhaust, under visible light revealed that RGO/CoPc/TiO2nanocomposites exhibited much higher photocatalytic activity than CoPc/TiO2and pure TiO2, indicating the ideal amount of RGO was 7.5 wt.%, the optimal amount of 7.5% RGO/CoPc/TiO2composite on each plat was 0.3g and the degradation efficiency of diethyl sulfide was about 90%.

Use of a modified vector model for odor intensity prediction of odorant mixtures.

Odor intensity (OI) indicates the perceived intensity of an odor by the human nose, and it is usually rated by specialized assessors. In order to avoid restrictions on assessor participation in OI evaluations, the Vector Model which calculates the OI of a mixture as the vector sum of its unmixed components' odor intensities was modified. Based on a detected linear relation between the OI and the logarithm of odor activity value (OAV-a ratio between chemical concentration and odor threshold) of individual odorants, OI of the unmixed component was replaced with its corresponding logarithm of OAV. The interaction coefficient (cosα) which represented the degree of interaction between two constituents was also measured in a simplified way. Through a series of odor intensity matching tests for binary, ternary and quaternary odor mixtures, the modified Vector Model provided an effective way of relating the OI of an odor mixture with the lnOAV values of its constituents. Thus, OI of an odor mixture could be directly predicted by employing the modified Vector Model after usual quantitative analysis. Besides, it was considered that the modified Vector Model was applicable for odor mixtures which consisted of odorants with the same chemical functional groups and similar molecular structures.

Research on odor interaction between aldehyde compounds via a partial differential equation (PDE) model.

In order to explore the odor interaction of binary odor mixtures, a series of odor intensity evaluation tests were performed using both individual components and binary mixtures of aldehydes. Based on the linear relation between the logarithm of odor activity value and odor intensity of individual substances, the relationship between concentrations of individual constituents and their joint odor intensity was investigated by employing a partial differential equation (PDE) model. The obtained results showed that the binary odor interaction was mainly influenced by the mixing ratio of two constituents, but not the concentration level of an odor sample. Besides, an extended PDE model was also proposed on the basis of the above experiments. Through a series of odor intensity matching tests for several different binary odor mixtures, the extended PDE model was proved effective at odor intensity prediction. Furthermore, odorants of the same chemical group and similar odor type exhibited similar characteristics in the binary odor interaction. The overall results suggested that the PDE model is a more interpretable way of demonstrating the odor interactions of binary odor mixtures.

An odor interaction model of binary odorant mixtures by a partial differential equation method.

A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE) method. Based on the measurement method (tangent-intercept method) of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture's odor intensity to the individual odorant's relative odor activity value (OAV). Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors) also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.

[Objective assessment of facial paralysis using infrared thermography and formal concept analysis].

This paper presented a novel approach to objective assessment of facial nerve paralysis based on infrared thermography and formal concept analysis. Sixty five patients with facial nerve paralysis on one side were included in the study. The facial temperature distribution images of these 65 patients were captured by infrared thermography every five days during one-month period. First, the facial thermal images were pre-processed to identify six potential regions of bilateral symmetry by using image segmentation techniques. Then, the temperature differences on the left and right sides of the facial regions were extracted and analyzed. Finally, the authors explored the relationships between the statistical averages of those temperature differences and the House-Brackmann score for objective assessment degree of nerve damage in a facial nerve paralysis by using formal concept analysis. The results showed that the facial temperature distribution of patients with facial nerve paralysis exhibited a contralateral asymmetry, and the bilateral temperature differences of the facial regions were greater than 0.2 degrees C, whereas in normal healthy individuals these temperature differences were less than 0.2 degrees C. Spearman correlation coefficient between the bilateral temperature differences of the facial regions and the degree of facial nerve damage was an average of 0.508, which was statistically significant (p < 0.05). Furthermore, if one of the temperature differences of bilateral symmetry on facial regions was greater than 0.2 degrees C, and all were less than 0.5 degrees C, facial nerve paralysis could be determined as for the mild to moderate; if one of the temperature differences of bilateral symmetry was greater than 0.5 degrees C, facial nerve paralysis could be determined as for serious. In conclusion, this paper presents an automated technique for the computerized analysis of thermal images to objectively assess facial nerve related thermal dysfunction by using formal concept analysis theory, which may benefit the clinical diagnosis and treatment of facial nerve paralysis.

Compound-specific nitrogen isotope of amino acids: Toward an improved understanding of mercury trophic transfer in different habitats.

Herein, we investigated the trophic transfer of mercury (Hg) through food chains in different habitats (namely aquatic, riparian, and terrestrial) through bulk stable isotope analysis of nitrogen (δ15Nbulk) and compound-specific isotope analysis of nitrogen in amino acids (δ15NAA) using bird feathers and their potential food sources from a Hg-contaminated site in southwest China. Results showed similar δ15Nphe for water birds (4.7 ± 2.6 ‰) and aquatic food sources (5.2 ± 2.1 ‰) and for land-based food sources (10.1 ± 0.4 ‰) and terrestrial birds (11.6 ± 3.0 ‰), verifying δ15Nphe as a potential discriminant indicator for different food sources. The trophic positions (TPs) of most organisms based on δ15Nbulk (TPbulk) tended to overestimate compared with those based on δ15NAA (TPAA), especially for predators (such as kingfisher: ΔTP = 1.3). Additionally, significant differences were observed in the aquatic, riparian, and terrestrial food webs between trophic magnification slope (TMS)bulk and TMSAA (p < 0.05). The trophic magnification factor (TMF)AA-multiple based on multiple-AAs in three food webs were higher than the TMFAA and TMFbulk, probably because of the greater variation of δ15Nbaseline, complex food sources or the notably different in individual organisms. Altogether, our results improve the understanding of Hg trophic transfer in aquatic, riparian, and terrestrial food webs.

Separation and quantification of tire and road wear particles in road dust samples: Bonded-sulfur as a novel marker.

Tire road wear particles (TRWPs) are a large source of microplastics in the environment, while the quantification of TRWPs is still challenging due to the complex interferences and the uncertainties and inconsistencies among different methods. This study developed a TRWPs quantification method using optimized pretreatments and bonded-sulfur as marker. Road dust samples (n = 48) were collected, pretreatments including density separation, digestion and extraction were optimized to remove interferences of the bonded-sulfur (minerals, sulfur-containing proteins, hydrosoluble/hydrophobic sulfur-containing substances). Presence of TRWPs in the samples was confirmed by microscopy and scanning electron microscopyenergy dispersive spectrometry. Bonded-sulfur in the samples were quantified by inductively coupled plasmamass spectrometry (ICPMS). Additionally, bonded-sulfur in tire wear particles (TWPs) abraded from tires of top 10 best-selling brands were measured to calculate conversion factor (1.1 ×104 µg/g) for the quantification of TRWPs in real samples. TRWPs contents were 5.40 × 104 µg/g11.02 × 104 µg/g and 2.36 × 104 µg/g5.30 × 104 µg/g in samples from heavy and light traffic roads, respectively. The method provided better recoveries (88-107%, n = 18) and repeatability (RSD=2.0-7.9%, n = 3) compared to methods using rubber, benzothiazole and organic zinc as markers. Furthermore, stability of the bonded-sulfur was validated by Raman and ICPMS. Thus, this accurate and stable quantification method could promote research on TRWPs.

Characteristic analysis for odor gas emitted from food waste anaerobic fermentation in the pretreatment workshop.

Gas chromatography-mass spectrometry, olfactometry, and other related methods were applied for the qualitative and quantitative analysis of the characteristics of odorous gases in the pretreatment workshop. The composition of odorous gases emitted from municipal food waste was also investigated in this study. The results showed that the tested gases are mainly composed of aromatic gases, which account for 49% of the total volatile organic compounds (VOC) concentrations. The nitrogenous compounds comprise 15% of the total concentration and the other gases comprise the remaining 36%. The level of odor concentration ranged from 2523 odor units (OU) m(-3) to 3577 OU m(-3). The variation of the total chemical composition ranged from 19,725 microg m(-3) to 24,184 microg m(-3). Among the selected four sampling points, the discharge outlet was detected to have the highest concentration in terms of odor, total chemical, sulfur compounds, and aromatics. The correlation analysis showed that the odor concentrations were evidently related to the total chemical composition, sulfur compounds, and aromatics (P < 0.05, n = 5). The odor activity value analysis identified the top three compounds, hydrogen sulfide (91.8), ethyl sulfide (35.8), and trimethylamine (70.6), which contribute to air pollution complaint of waste materials.