Nitrogen (N) deposition poses a severe risk to global terrestrial ecosystems, and managing this threat is an important focus for air pollution science and policy. To understand and manage the impacts of N deposition, we need metrics which accurately reflect N deposition pressure on the environment, and are responsive to changes in both N deposition and its impacts over time. In the UK, the metric typically used is a measure of total N deposition over 1–3 years, despite evidence that N accumulates in many ecosystems and impacts from low-level exposure can take considerable time to develop. Improvements in N deposition modelling now allow the development of metrics which incorporate the long-term history of pollution, as well as current exposure. Here we test the potential of alternative N deposition metrics to explain vegetation compositional variability in British semi-natural habitats. We assembled 36 individual datasets representing 48,332 occurrence records in 5479 quadrats from 1683 sites, and used redundancy analyses to test the explanatory power of 33 alternative N metrics based on national pollutant deposition models. We find convincing evidence for N deposition impacts across datasets and habitats, even when accounting for other large-scale drivers of vegetation change. Metrics that incorporate long-term N deposition trajectories consistently explain greater compositional variance than 1–3 year N deposition. There is considerable variability in results across habitats and between similar metrics, but overall we propose that a thirty-year moving window of cumulative deposition is optimal to represent impacts on plant communities for application in science, policy and management.

The growing production and extensive use of organophosphate flame retardants (OPFRs) have led to an increase in their environmental distribution and human exposure. Developmental toxicity is a major concern of OPFRs' adverse health effects. However, the impact of OPFRs exposure on vascular development and the toxicity pathway for developmental defects are poorly understood. In this study, we investigated the effects of exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCPP), a frequently detected OPFR, on early vascular development, and the possible role of nuclear factor erythroid 2-related factor (Nrf2)-dependent angiogenic pathway in TDCPP's vascular toxicity. TDCPP exposure at 300 and 500 μg/L impeded the growth of intersegmental vessels (ISV), a type of microvessels, as early as 30 hpf. Consistently, a similar pattern of decreased extension and remodeling of common cardinal vein (CCV), a typical macrovessel, was observed in zebrafish at 48 hpf and 72 hpf. Developing vasculature in zebrafish was more sensitive than general developmental parameters to TDCPP exposure. The expression of genes related to VEGF signaling pathway dose-dependently decreased in TDCPP-treated larvae. In in vitro experiments using human umbilical vein endothelial cells (HUVECs), the increased cell proliferation induced by VEGF was suppressed by TDCPP exposure in a dose-dependent fashion. In addition, we found a repression of Nrf2 expression and activity in TDCPP-treated larvae and HUVECs. Strikingly, the application of CDDO-Im, a potent Nrf2 activator, enhanced VEGF and protected against defective vascular development in zebrafish. Our results reveal that vascular impairment is a sensitive index for early exposure to TDCPP, which could be considered in the environmental risk assessment of OPFRs. The identification of Nrf2-mediating VEGF pathway provides new insight into the adverse outcome pathway (AOP) of OPFRs.

Magnetic properties of urban street dust can be used as a proxy of urban pollution. In this study, magnetic measurements on 160 street dust samples, collected from five different functional areas (industrial, traffic, commercial, residential and clean areas) in sixteen administrative districts in Shanghai, China, were systematically conducted. It is showed that magnetic carriers were predominately coarse-grain ferrimagnetic particles. Meantime, concentration-related magnetic parameters showed significant variations among the functional areas and administrative units. Magnetic susceptibility (χ) decreased in the following order: industrial area (IA) > traffic area (TA) > commercial area (CoA) > residential area (RA) > clean area (ClA). Moreover, combined with the analyses conducted using a scanning electron microscope and an energy dispersive X-ray spectrometer (SEM-EDX), it is found that spherical magnetic particles originating mainly from anthropogenic sources were abundant in industrial areas. Baoshan district, which is heavily impacted by industrial activities, showed the highest χ value among the administrative units. Additionally, the correlations of street dust χ value with population, value of industrial output and the gross domestic product (GDP) in Shanghai and other cities indicated that χ is positively correlated with the city GDP as well as the population size (PS) to some extent. This study demonstrates that magnetic parameters of street dust can be used as an effective tool for monitoring environmental pollution and industrial activities in urban environments.

Cadmium (II) can potentially alter the microbial community structure and molecular ecological network in activated sludge systems. In this study, we used Illumina sequencing combined with an RMT-based network approach to show the response of the microbial community and its network structure to Cd (II) in activated sludge systems. The results demonstrated that 1 mg/L Cd (II) did not have chronic negative effects on chemical oxygen demand (COD) reduction and denitrification processes, but negatively affected the nitrification process and phosphorus removal. In contrast, 10 mg/L Cd (II) adversely affected both COD and nutrient removal, and reduced the microbial diversity and changed the overall microbial community structure. The relative abundances of Nitrosomonadaceae, Nitrospira, Accumulibacter and Acinetobacter, which are involved in nitrogen removal, significantly decreased with increases in the Cd (II) concentration. In addition, molecular ecological network analysis showed that the networks sizes in the presence of higher levels of Cd (II) were smaller than in the control, but the nodes were more closely connected with neighbors. These shifts in bacterial abundance and the bacterial network structure may be responsible for the deterioration of COD and nutrient removal. Overall, this study provides new insights into the effects of Cd (II) on the bacterial community and its interactions in activated sludge systems.

Hexa-mix-chlorinated/brominated benzenes (HXBs), a group of newly found analogues of hexachlorobenzene (HCB) and hexabromobenzene (HBB), may exhibit similar environmental risks and toxicities as HCB and HBB, and therefore possess high interests in environmental and toxicological research. Yet information regarding HXBs in the environment remains scarce. In this study, we developed an isotope dilution method for quantitative and semiquantitative determination of five HXBs in fly ash, soil and air using gas chromatography high resolution mass spectrometry (GC-HRMS) in multiple ion detection mode. The samples were Soxhlet-extracted and purified with multilayer composite silica gel-alumina columns, followed by GC-HRMS detection. Identification of HXBs was conducted by the comparison between theoretical and detected mass spectra using paired-samples T test and cosine similarity analysis. Two HXBs (C₆BrCl₅ and C₆Br₄Cl₂) with reference standards were quantitatively determined while the rest three (C₆Br₂Cl₄, C₆Br₃Cl₃ and C₆Br₅Cl) without reference standards were semiquantitatively analyzed by sharing the calibration curves of C₆BrCl₅ and C₆Br₄Cl₂ in cooperation with isotopologue distribution computation. The accuracies for C₆BrCl₅ and C₆Br₄Cl₂ were 87.3–107.8% with relative standard deviations (RSD) of 2.8–5.0%. The method limits of quantification of the HXBs were 0.10 ng/g in fly ash and soil samples and 0.09 pg/m³ in ambient air samples. The recoveries ranged from 42.7% to 102.1% with RSD of 3.7–13.9%. This method has been successfully applied to the analysis of the HXBs in the environmental samples. The total concentrations of HXBs in the fly ash, soil and ambient air samples were 19.48 ng/g, 10.44 ng/g and 5.13 pg/m³, respectively, which accounted for 10.6%, 0.4% and 10.8% of the corresponding total concentrations of HCB and HBB. This study provides a reference method for quantitative and/or semiquantitative analyses of novel mix-halogenated organic compounds, and sheds light on the full picture of HXBs pollution in the environment.

Nitrous oxide (N2O) is a devastating greenhouse gas mainly released from soils to the atmosphere. Pasture soils, particularly acidic in nature, are large contributors of atmospheric N2O through deposition of urine-N. Devising strategies for reducing N2O emissions in acidic soils are the utmost need of the time. Therefore, the present study was carried out to investigate the possible efficacy of dolomite application to reduce N2O emissions from urine treated acidic soil. Application of urine to soil enlarged the production of NH4+-N, NO3−-N, microbial biomass C (MBC) and dissolved organic C (DOC), resulting in higher N2O emissions as compared to the control (soil only). The highest N2O emission rate (1.35 μg N2O-N kg−1 h−1) and cumulative flux (408 μg N2O-N kg−1) occurred in urine only treated soil. Dolomite addition, especially higher application dose, greatly reduced N2O emissions through improved soil pH. The results suggest that increasing pH of acidic soils is a good applicable approach for reducing N2O emissions from urine-treated soils.

This review aims to gather and summarize information about the occurrence of emerging contaminants and antibiotic resistance genes in environmental matrices in Latin America. We aim to contribute to future research by compiling a list of priority pollutants adjusted to the needs and characteristics of Latin America, according to the data presented in this study. In order to perform a comprehensive research and secure a representative and unbiased amount of quality data concerning emerging contaminants in Latin America, the research was performed within the Scopus® database in a time frame from 2000 to July 2019. The countries with higher numbers of published articles were Brazil and México, while most studies were performed in the surroundings of Mexico City and in Southern and Southeastern Brazil. The main investigated environmental matrices were drinking water and surface water. The presence of antibiotic resistance was frequently reported, mainly in Brazil. Monitoring efforts should be performed in other countries in Latin America, as well as in other regions of Brazil and México. The suggested priority list for monitoring of emerging contaminants in Latin America covers: di(2-ethylhexyl) phthalate (DEHP), bisphenol-A (BP-A), 4-nonylphenol (4-NP), triclosan (TCS), estrone (E1), estradiol (E2), ethinylestradiol (EE2), tetracycline (TC), amoxicillin (AMOX), norfloxacin (NOR), ampicillin (AMP) and imipenem (IMP). We hope this list serves as a basis for the orientation of the future research and monitoring projects to better understand the distribution and concentration of the listed emerging substances.

Emissions from passenger cars are one of major sources that deteriorate urban air quality. This study presents characterization of real-drive emissions from three Euro 6 emission level passenger cars (two gasoline and one diesel) in terms of fresh particles and secondary aerosol formation. The gasoline vehicles were also characterized by chassis dynamometer studies. In the real-drive study, the particle number emissions during regular driving were 1.1–12.7 times greater than observed in the laboratory tests (4.8 times greater on average), which may be caused by more effective nucleation process when diluted by real polluted and humid ambient air. However, the emission factors measured in laboratory were still much higher than the regulatory value of 6 × 1011 particles km−1. The higher emission factors measured here result probably from the fact that the regulatory limit considers only non-volatile particles larger than 23 nm, whereas here, all particles (also volatile) larger than 3 nm were measured. Secondary aerosol formation potential was the highest after a vehicle cold start when most of the secondary mass was organics. After the cold start, the relative contributions of ammonium, sulfate and nitrate increased. Using a novel approach to study secondary aerosol formation under real-drive conditions with the chase method resulted mostly in emission factors below detection limit, which was not in disagreement with the laboratory findings.

In recent decades, most lakes in Eastern China have suffered unprecedented nitrogen pollution, making them potential “hotspots” for N2O production and emission. Understanding the mechanisms of N2O production and quantifying emissions in these lakes is essential for assessing regional and global N2O budgets and for mitigating N2O emissions. Here, we measure isotopic compositions (δ15N-N2O and δ18O-N2O) and site preference (SP) of dissolved N2O in an attempt to differentiate the relative contribution of N2O production processes in the shallow, eutrophic Chaohu Lake, Eastern China. Our results show that the bulk isotope ratios for δ15N-N2O, δ18O-N2O, and SP were 5.8 ± 3.9‰, 29.3 ± 13.4‰, and 18.6 ± 3.2‰, respectively. More than 76.8% of the dissolved N2O was produced via microbial processes. Findings suggest that dissolved N2O is primarily produced via nitrification (between 27.3% and 48.0%) and denitrification (between 31.9% and 49.5%). In addition, isotopic data exhibit significant N2O consumption during denitrification. We estimate the average N2O emission rate (27.5 ± 26.0 μg N m−2 h−1), which is higher than that from rivers in the Changjiang River network (CRN). We scaled-up the regional N2O emission (from 1.98 Gg N yr−1 to 4.58 Gg N yr−1) using a N2O emission factor (0.51 ± 0.63%) for shallow lakes in the middle and lower region of the CRN. We suggest that beneficial circumstances for promoting complete denitrification may be helpful for reducing N2O production and emissions in fresh surface waters.

Tributyl phosphate (TBP) is recognised as a global environmental contaminant because of its wide use in floatation reagents, nuclear fuel reprocessing and plasticisers. This contaminant is hardly degraded by hydrolysis in the environment due to its special physicochemical properties. In this study, one TBP-degrading strain was isolated from TBP-contaminated abandoned mine tailings, and 16S rRNA identification revealed that the strain belonged to the genus Sphingomonas. Results validated that the strain could utilise TBP as the sole carbon source, and vitamin was not the essential factor for its growth. Liquid chromatography time-of-flight mass spectrometry analysis identified di-n-butyl phosphate (DnBP) and mono-n-butyl phosphate (MnBP) as the intermediate metabolites for TBP biodegradation. No obvious change in carbon and hydrogen isotope composition was observed in biodegradation processes (cell suspension and crude extract degradation), which indicated that the first irreversible bond cleavage did not involve carbon or hydrogen. Hence, the TBP degradation scheme by Sphingomonas sp. proposed that the first irreversible step of TBP transferred to DnBP would lead to PO bond cleavage. This study combined the identification of products and isotope fractionation in substrates to investigate the transformation mechanism, thereby providing an eco-friendly and cost-effective way for the in situ bioremediation of TBP-contaminated sites by the isolated TBP degradation strain.