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Coal-fired industrial boilers (CFIBs) that provide heat for industrial production operate to produce large quantities of wastes containing hazardous trace elements (HTEs), threatening the quality of the environment. Based on the established facility-level material flow inventory of five typical HTEs (Hg, As, Cd, Cr, and Pb) of Chinese CFIBs in 2020, we explored the enrichment characteristics and environmental risks of HTEs in wastes at the regional scale from the perspective of substance flow and enrichment levels. Results showed that the shares of HTEs entering the waste stream were 2.2-16.8 % higher in the focus regions of continuous improvement of air quality compared to the non-focus regions, explained by the higher synergistic control efficiencies of their air pollution control facilities (ACPFs), at 86.6-90.4 % (Hg), 98.6-99.1 % (As), 95.1-95.9 % (Cd), 93.2-94.8 % (Cr), and 97.1-98.0 % (Pb), respectively. In addition, the national averages of HTEs in slag, fly ash, and flue gas desulphurisation (FGD) were simulated to be 0.15-0.87 g/t, 3.25-18.44 g/t, 0.30-0.96 g/t, 19.76-70.11 g/t, and 15.85-73.74 for Hg, As, Cd, Cr, and Pb, respectively. Nationally, the integrated environmental risks of the five HTEs in slag, fly ash, and FGD residue exhibited Considerable, Very High, and Very High level of environmental risk, with the cumulative environmental risk indexes of 171, 317, and 281, respectively. Hg and Cd were the major contributors to the environmental risks of slag, fly ash, and FGD residue, with environmental risk contributions ranging from 23.8 to 82.3 % and 16.0 to 66.1 %, respectively. Results can provide data support for modelling the environmental release of HTEs from wastes and formulating control strategies for environmental management agencies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Coking industry is usually regarded as a high pollution and high energy consumption industry. China is accelerating its efforts to reduce pollution and carbon emissions in the industrial sector, which has received little attention as the world's largest producer of coke. Therefore, in this study, the trend of air pollution and carbon emissions in China's coking industry and the path of coordinated emission reduction were studied. The results indicate that the average annual emissions of PM, SO 2 , NOx, VOCs, and CO 2 in China's coking industry from 2012 to 2022 amount to 205.98, 69.47, 193.45, 599.80 Gg and 191.10 Tg, respectively. The main sources of PM, SO 2 , NOx, VOCs and CO 2 in coking industry were coal preparation (51.5 %), charge and pushing (39.5 %), coke oven gas (99.8 %), byproduct recovery (47.0 %) and fuel combustion (87.5 %). The emissions from coking plants in central and southern Shanxi, eastern and southern Hebei, and central Shandong are the most concentrated. Ultra-low emission transformation and deep treatment of VOCs have greatly reduced pollutant emissions in key areas of air pollutant control, but the actual emission reduction effect of these measures has been weakened by the additional emissions caused by the increase of coke production in other non-key areas. The research on synergetic emission reduction path shows that there is a great synergistic benefit between air pollutants and CO 2 emission reduction in coking industry. It is estimated that the APeq (air pollutants and carbon equivalent) of China's coking industry in 2025, 2028 and 2030 will decrease by 38.2 %, 63.5 % and 70.8 % respectively compared with 2022. With the continuous promotion of pollution reduction and carbon reduction measures, the emission reduction potential of China's coking industry will gradually shift from key areas to non-key areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The association between air pollutants and hepatobiliary pancreatic diseases remains inconclusive. This study analyzed up to 247,091 participants of White European ancestry (aged 37 to 73 years at recruitment) from the UK Biobank, a large-scale prospective cohort with open access. An air pollution score was utilized to assess the combined effect of PM 2.5 , PM 2.5 - 10 , PM 10 , NO 2 , and NO X on total hepatobiliary pancreatic diseases, liver diseases, cholecyst diseases, and pancreatic diseases. Cox proportional hazard models were employed to evaluate the relationships between air pollutants and the incidence of these diseases. Restricted cubic spline regressions were used to examine the dose-response association between air pollutants and the risk of hepatobiliary pancreatic diseases. We identified 4865 cases of total hepatobiliary pancreatic diseases, over a median follow-up of 10.86 years. The air pollution scores were moderately associated with increased liver disease risk (HR = 1.009, 95 % CI: 1.004, 1.014), but not with cholecyst and pancreatic diseases. Among the individual air pollutants, PM 2.5 (HR = 1.069, 95 % CI: 1.025, 1.115) and PM 10 (HR = 1.036, 95 % CI: 1.011, 1.061) significantly increased liver disease risk. Males showed a higher risk of liver diseases with PM 2.5 (HR = 1.075, 95 % CI: 1.015, 1.139). Additionally, individuals with overweight (HR = 1.125, 95 % CI: 1.052, 1.203), age ≥ 60 and ≤73 (HR = 1.098, 95 % CI: 1.028, 1.172), and alcohol intake ≥ 14 unit/week (HR = 1.078, 95 % CI: 1.006, 1.155) had a higher risk of developing liver diseases at high expose to PM 2.5 . This study suggests that prolonged exposure to ambient air pollutants may elevate the risk of liver diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Parabens are largely concentrated in food waste (FW) due to their large consumption as the widely used preservative. To date, whether and how they affect FW resource recovery via anaerobic fermentation is still largely unknown. This work unveiled the hormesis-like effects of two typical parabens (i.e., methylparaben and n-butylparaben) on VFAs production during FW anaerobic fermentation (i.e., parabens increased VFAs by 6.73-14.49 % at low dose but caused 82.51-87.74 % reduction at high dose). Mechanistic exploration revealed that the parabens facilitated the FW solubilization and enhanced the associated substrates' biodegradability. The low parabens enriched the functional microorganisms (e.g., Firmicutes and Actinobacteria) and upregulated those critical genes involved in VFAs biosynthesis (e.g., GCK and PK) by activating the microbial adaptive capacity (i.e., quorum sensing and two-component system). Consequently, the metabolism rates of fermentation substrates and subsequent VFAs production were accelerated. However, due to increased biotoxicity of high parabens, the functional microorganisms and relevant metabolic activities were depressed, resulting in the significant reduction of VFAs biosynthesis. Structural equation modeling clarified that microbial community was the predominant factor affecting VFAs generation, followed by metabolic pathways. This work elucidated the dose-dependent effects and underlying mechanisms of parabens on FW anaerobic fermentation, providing insights for the effective management of FW resource recovery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The mercury oxidation performance of Ce/TiO 2 catalyst can be further enhanced by transition metal modifications. This study employed density functional theory (DFT) calculations to investigate the adsorption and oxidation mechanisms of Hg 0 on Ce/TiO 2 (001) and its transition metal modified surfaces. According to the calculation results, Ru-, Mo-, Nb-, and Mn-doping increased the affinity of the Ce/TiO 2 (001) surface towards Hg 0 and HCl, thereby facilitating the efficient capture and oxidation of Hg 0 . The increased adsorption energy (E ads ) of the intermediate HgCl on the modified surfaces could promote its conversion to the final product HgCl 2 . The modification of transition metals impeded the desorption of the final products HgCl 2 and HgO, but it did not serve as the rate-determining step. The oxidation of Hg 0 by lattice oxygen and HCl followed the Mars-Maessen and Langmuir-Hinshelwood mechanisms, respectively. HCl exhibited higher mercury oxidation ability than lattice oxygen. The reactivity of lattice oxygen could be further improved by doping transition metals, their promotion order was Ru > Nb > Mo > Mn. In a HCl atmosphere, Mn modification could significantly reduce the energy barrier for HCl activation and HgCl 2 formation, providing the optimal enhancement for the mercury oxidation ability of Ce/TiO 2 catalyst. The screening method of transition metal modified components based on surface adsorption reaction and oxidation energy barrier was proposed in this study, which provided theoretical guidance for the development of CeTi based catalysts with high mercury oxidation activity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

O 3 pollution in China has worsened sharply in recent years, and O 3 formation sensitivity (OFS) in many regions have gradually changed, with eastern China as the most typical region. This study constructed the transport networks of O 3 and NO 2 in different seasons from 2017 to 2020. The transport trends and the clustering formation patterns were summarized by analyzing the topological characteristics of the transport networks, and the patterns of OFS changes were diagnosed by analyzing the satellite remote sensing data. Based on that, the main clusters that each province or city belongs to in different pollutant transport networks were summarized and proposals for the inter-regional joint prevention and control were put forward. As the results showed, O 3 transport activity was most active in spring and summer and least active in winter, while NO 2 transport activity was most active in autumn and winter and least active in summer. OFS in summer mainly consisted of transitional regimes and NO x -limited regimes, while that in other seasons was mainly VOC-limited regimes. Notably, there was a significant upward trend in the proportion of transitional regimes and NO x -limited regimes in spring, autumn, and winter. For regions showing NO x -limited regime, areas with higher out-weighted degrees in the NO 2 transport network should focus on controlling local NO x emissions, such as central regions in summer. For regions showing VOC-limited regime, areas with higher out-weighted degrees in the O 3 transport network should focus on controlling local VOCs emissions, such as central and south-central regions in summer. For regions that belong to the same cluster and present the same OFS in each specific season, regional cooperative emission reduction strategies should be established to block important transmission paths and weaken regional pollution consistency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Sludge poses a serious threat to the environmental health. Hot-pressing drying has been proven efficient in sludge treatment because of the reduced thermal contact resistance, rapid increase in sludge temperature, and high drying rate. Sludge extracellular polymeric substances (EPS) significantly influence moisture transfer. However, whether in hot-pressing or traditional thermal drying, the effect of EPS on sludge moisture-holding capacity is rarely reported. Thereby, this study investigated the relationship between hydrophilic/hydrophobic characteristics of EPS and sludge moisture-holding capacity at various drying time and mechanical compression using XAD resin fractionation. Thermodynamic analysis indicated that sludge moisture desorption isotherms, net isosteric heat of desorption, and differential entropy presented a downward trend with the increase in drying time and mechanical compression, suggesting reduced sludge moisture-holding capacity. EPS analysis showed that at the same drying time, applying 25 kPa mechanical compression increased sludge temperature by 16 % and protein content by 13.8 %. At the same sludge temperature, protein content rose by 7.3 % compared to the drying without mechanical compression. It was concluded that the fast rise in sludge temperature and the mechanical extrusion facilitated the destruction of sludge microbial flocs, accelerating the release of intracellular and EPS-bound moisture and contributing to the decrease in moisture-holding capacity. Besides, tryptophan protein-like substances were the major source of hydrophilic/hydrophobic organic matter, compared to polysaccharide and humic acid-like substances. The gradually reduced sludge moisture-holding capacity was divided into three stages. Below 67 °C, the moisture desorption was dominated by the release of intracellular moisture. Below 85 °C, the increase in protein and the enhanced exposure of hydrophobic functional groups in protein improved the hydrophobicity of EPS. Above 85 °C, protein consumption due to thermal decomposition and browning reaction facilitated the desorption of EPS-bound moisture. Hence, this study provided novel insights into the mechanism of sludge drying., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, nitrogen-doped modified activated carbons were synthesized for H 2 S removal from Zhuxi activated carbon and 4,4'-bipyridine as raw material and nitrogen source, respectively. The synthesis strategy was hydrothermal treatment and subsequent NH 3 annealing, and the formation and conversion patterns of the different N configurations were investigated. When the annealing temperatures were 500 °C and 600 °C, N-5 account for the majority. As the annealing temperature increased, the proportion of N-6 gradually increased. After the temperature increased to 1000 °C, N-5 and N-6 were converted to N-Q to a certain degree, while the amount of nitrogen doping decreased significantly. The sample H160-0.2-800 exhibited excellent H 2 S removal with a high sulfur capacity of up to 206.89 mg/g, significantly higher than that of the original activated carbon ZX1200 (67.56 mg/g). The reason for this is that the micropores (V mic  = 0.5155 cm 3 /g) and specific surface area (S BET  = 1369.5 m 2 /g) of the modified activated carbon are more developed than those of the original activated carbon. A high nitrogen content (3.14 wt%) and N-6 configuration proportion (73.56 %) are significant reasons for the excellent adsorption properties. The mechanism of the catalytic oxidation was investigated. The introduction of surface nitrogen-containing functional groups alkalizes the activated carbon surface, enhancing the adsorption and dissociation of H 2 S and O 2 and facilitating the formation of sulfur radicals and elemental sulfur., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Light profoundly modulates the algal-bacterial membrane bioreactor (algal-bacterial MBR) performance. Yet, its outdoor deployment grapples with the inherent diurnal cycle of sunlight, engendering suboptimal light conditions. The adaptability of such systems to these fluctuating light conditions and their implications for practical outdoor applications remained an under-explored frontier. In response, this study meticulously scrutinized two laboratory-scale algal-bacterial MBRs under varying light regimes: a 24-h continuous and a 12-h cyclic illumination. Over 70 days, continuous illumination was observed to yield superior biomass production and total nitrogen and total phosphorus removal efficiencies compared to its cyclic counterpart. Contrarily, when focusing on membrane fouling, the 12-h cyclic illumination exhibited lower membrane fouling. The spectral analyses coupled with adhesion ability evaluation, traced the enhanced membrane fouling under continuous illumination to the elevated organics and heightened adhesive properties of the flocs. Given the tangible benefits of reduced membrane fouling and the potential harnessing of solar radiation, the 12-h cyclic illumination emerges as an economically astute operational paradigm for algal-bacterial MBRs. The significance of this study is to promote the application of algal-bacterial MBR in sewage treatment and provide robust support for the development of green technology in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The Beijing-Tianjin-Hebei (BTH) region, a highly industrialized area in China, boasts a concentration of coking plants that constitute a vital component of the steel industry. In recent years, the Chinese government has implemented measures including backward production capacity elimination (BPCE), ultra-low emission technology transformation (ULET), and deep treatment of volatile organic compounds (DTV), to promote technological progress in the coking industry and mitigate the impact of pollutant emissions. This study focuses on the emission trends, reduction effects of various measures, and the impact on air quality and human health in the regional scale. The findings reveal that in 2015, the emissions of PM, SO 2 , NOx and VOCs of the coking industry in BTH region were 29.15, 9.64, 26.62 and 82.99 Gg (1000 tons/year) respectively. However, by 2019, these emissions had significantly decreased by 19.95, 5.78, 18.69, and 22.53 Gg, respectively. Of these reductions, ULET contributed about 80.3 % of NOx and SO 2 , and 57.4 % of PM. Meanwhile, DTV and BPCE contributed 49.2 % and 50.7 % of VOCs emission reduction, respectively. Despite the improvement effect on PM 2.5 , SO 2 , and NO 2 is limited, the substantial decrease in VOCs (particularly benzene) resulted in a significant reduction in the coking industry's contribution to the atmospheric benzene concentration, dropping from 15.9 % in 2015 to 11.6 % in 2019. Moreover, the lifetime cancer risk (LCR) contribution of benzene inhalation in the BTH region also decreased from 1.7 × 10 -6 to 1.2 × 10 -6 . Looking ahead to 2025, the continued implementation of DTV will be expected to reduce VOCs emissions by 24.41Gg. This will bring the industry's contribution to the benzene concentration down to 6.8 % and the cancer risk of the population to an acceptable level (LCR < 1 × 10 -6 ). Additionally, the deep treatment of VOCs in coking plants will significantly reduce the health risks faced by people living in the vicinity of the plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Synthetic microfibers (MFs), which are Microplastics (MPs), have not received attention commensurate with their abundance in the environment. Currently, limited studies on MFs have focused on their effects on marine organisms. It is therefore necessary to conduct exposure experiments of MFs on freshwater organisms to provide reference data for the ecological risk assessment of MFs. As a primary producer in freshwater ecosystems, microalgae have an ecological niche that is highly overlapping with that of MFs. In this study, we examined the effects of MFs on the growth of Chlorella and indicators of oxidative stress to examine their potential risk on the microalgae population. The results showed that inhibition rate of microalgae increased with MF concentration in the range of 0.01-100 mg/L. Compared with natural fibers such as cotton and wool, PET and PP fibers showed significant growth inhibition, but less so when in fragment form with the same material and concentration. PP and PET particles, whether fibers or fragments, increased the total antioxidant capacity of microalgal cells and caused oxidative damage. To determine the influence of MFs on the interaction of cells in the environment, the exchanged substances and accumulated energy of microalgae cells were also detected. The results indicated that PP and PET fibers, as well as fragments, increased the diameter and membrane permeability of microalgae cell, thus interfering with the cell division and substance exchange processes. PET fibers and fragments showed different interactions at the level of individual cells and populations. This suggests that the evaluation of MPs should consider examinations from cells to population and even community levels in the future., Competing Interests: Declaration of competing interest The authors: Cheng Shuo, Jessica, Kunio Yoshikawa, and Jeffrey S. Cross declared no potential conflicts of interest with respect to the research, author-ship, and/or publication of this article., (Copyright © 2023. Published by Elsevier B.V.)

Non-road construction equipment (NRCE) is an important source of air pollution, and it is crucial to fully understand the impact of NRCE on atmospheric PM 2.5 and O 3 pollution. However, systematic assessment of the impact of NRCE emissions on the atmosphere is lacking, especially with the latest implementation of the Stage IV Standard, and current research progress is insufficient for the development of effective control measures. This study estimated NRCE emission inventories at different emission standard stages and their impact on the atmosphere, using the "2 + 26" cities as the case study area. The results showed that the total NRCE emissions of CO, NO x , VOC, and PM 2.5 were 387, 418, 82, and 24 kt in 2015 and 319, 262, 62, and 15 kt in 2020 and are predicted to be 270, 226, 48, and 10 kt in 2025, respectively. Simulation results showed that the contributions of NRCE to NO 3 - , NO 2 , PM 2.5 , and O 3 were 16.7 %, 18.9 %, 7.7 %, and 8.2 % in 2015 to 13.6 %, 18.4 %, 6.5 %, and 6.7 % in 2020, respectively. In both 2015 and 2020, NRCE emissions in southern cities showed greater impacts on the average concentrations in the "2 + 26" cities than those in northern cities. The contributions of local NRCE emissions to local PM 2.5 and O 3 concentrations in the 28 cities ranged from 30 %-59 % and 13 %-39 %, respectively. The O 3 sensitivity estimated by the HDDM illustrated that nonlinear characteristics highlighted the importance of coordinated control of NO x and VOC and can inspire development of post-processing technology and electricity substitution. The belt-like area connecting Zhengzhou to Beijing showed higher exposure concentrations of PM 2.5 and O 3 , and the concentration exposure in urban areas was much higher than that in the rural and other areas. The environmental impact assessment of NRCE emissions can provide guidance for its management and development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The eastern China presented the most serious O 3 pollution and increasingly prominent regional characteristics. To understand the transport characteristics of O 3 and its precursors and identify their potential relationships are of great guiding significance for interregional joint prevention and control. In this study, the annual and seasonal transport networks of O 3 and its precursors (NO 2 and CO) during 2017-2021 were constructed by applying the complex network method to air quality observations. And the key spatial clusters, the spillover paths and the potential links among pollutants were comprehensively analyzed based on the topological characteristic analysis of the established air pollutant transport networks. As the results showed, O 3 pollution in the eastern China was affected by active regional transports of O 3 and its precursors. Regional transports of O 3 , NO 2 , and CO were more prominent in autumn and showed high synchronization. The regional transport of precursors, especially NO x , was an important cause of regional O 3 pollution. Air pollutant transport characteristics varied with seasons and regions, which demonstrating the importance of regulating seasonal and regional differentiated joint prevention and control strategies, especially for NO x . The results of this study can provide science-based guidance for the regional cooperative control of O 3 pollution in the eastern China, and the application of complex networks can also provide a new methodological perspective for the study of air pollution transmission., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Cadmium (Cd) is a hazardous environmental heavy metal with a prolonged biological half-life. Due to the main route of foodborne exposure, the intestinal tract is particularly vulnerable to Cd-induced toxicity. However, the chronic toxicity and underlying mechanisms of Cd in intestinal diseases, including colorectal cancer (CRC), still remain vague. Herein, we aim to investigate the long-term effects of Cd exposure on CRC development and the key signaling event. Our findings indicate that chronic and low-dose exposure to Cd promoted the invasion and metastasis capability of CRC cells in vitro and in mice, with a marginal increase in cell growth. The expression of cell junction-related genes was down-regulated while those molecules that facilitate cell mobility were significantly increased by Cd exposure. Epidermal growth factor receptor (EGFR) signaling was identified to play the dominant role in Cd-promoted CRC metastasis. Interestingly, Cd activated EGFR in a non-canonical manner that exhibited distinct signaling dynamics from the canonical ligand. In contrast to EGF, which induced transient EGFR signaling and ERK activation, Cd promoted sustained EGFR signaling to trigger Akt/mTOR cascade. The unique signaling dynamics of EGFR induced by Cd provoked responses that preferably enhanced the metastatic capacity rather than the growth. Furthermore, blockade of EGFR abrogated the promoting effects of Cd on the liver metastasis of CRC cells. In conclusion, this study provides a better understanding of the long-term influences of environmental Cd on CRC metastasis and reveals the unique EGFR signaling dynamics induced by Cd exposure., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Given the concerns about climate change, energy sustainability, and public health, the reuse of kitchen wastes (KW) is attracting increasing interest. In China, the municipal solid waste sorting scheme has increased the available KW. To assess the available KW and the climate change mitigation potential of KW utilization for bioenergy in China, three scenarios (base, conservative, and ambitious) were defined. A new framework was implemented to assess the climate change impacts of bioenergy. The annual available KW ranged from 11.450 million dry tons (in metric) under the conservative scenario to 22.898 million dry tons in the ambitious scenario, and had the potential to produce 12.37 × 10 6 -24.74 × 10 6 MWh heat and 9.62 × 10 6 -19.24 × 10 6 MWh power. The total potential climate change impacts of KW for combined heat and power were 3.339-6.717 million tons CO 2 eq in China. The highest eight provinces and municipalities contributed over half of the national total. Among the three components of the new framework, fossil fuel-derived greenhouse gas emissions and biogenic CO 2 emissions were positive. The difference in carbon sequestration was negative and ensured a lower integrated life-cycle climate change impacts than that of natural gas-derived combined heat and power. The mitigation effects of using KW as a substitute for natural gas and synthetic fertilizers were 2.477-8.080 million tons CO 2 eq. These outcomes can inform relevant policymaking and benchmark climate change mitigation in China. The conceptual framework of this study can also be adapted for applications in other countries or regions worldwide., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Environmental impact evaluation of buildings is critical for further analysis and optimization of pig farms for sustainable pork production. This study is the first attempt to quantify the carbon and water footprints of a standard intensive pig farm building using building information modeling (BIM) and operation simulation model. The model was constructed with carbon emission and water consumption coefficients, and a database was built. The results showed that the operational stage of pig farm accounted for most of the carbon footprint (49.3-84.9 %) and water footprint (65.5-92.5 %). Building materials production ranked second in carbon (12.0-42.5 %) and water footprints (4.4-24.9 %), and pig farm maintenance ranked third in carbon (1.7-5.7 %) and water footprints (0.7-3.6 %). Notably, the mining and production stages of building materials contributed the largest carbon and water footprints of pig farm construction. Masonry materials have a significant impact on the overall carbon and water footprints of the pig farm. Pig farm using aerated concrete could reduce 41.1 % of the total carbon footprint and 58.9 % of the total water footprint compared to that using coal gangue sintered brick and autoclaved fly ash brick. This study presented a BIM-enabled method for carbon and water footprint analysis of pig farms and illustrated how the model can be used to facilitate the low carbon design of agricultural buildings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

VOCs, as the common precursor of PM 2.5 and O 3 pollution, has not been paid enough attention in the previous phase. How to implement scientific and effective emission reduction on VOC sources is the focus of the next step in improving the atmospheric environmental quality in China. In this study, based on observations of VOC species, PM 1 components and O 3 , the distributed lag nonlinear model (DLNM) was used to investigate the nonlinear and lagged effects of key VOC categories on secondary organic aerosol (SOA) and O 3 . The control priorities of sources were determined by combining the VOC source profiles, which were afterwards verified using the source reactivity method and Weather Research and Forecasting Model-Community Multi-scale Air Quality Model (WRF-CMAQ). Finally, the optimized control strategy of VOC source was proposed. The results showed that SOA was more sensitive to benzene and toluene, and single-chain aromatics, while O 3 was more sensitive to dialkenes, C 2 -C 4 alkenes, and trimethylbenzenes. The optimized control strategy based on the total response increments (TRI) of VOC sources suggests that passenger cars, industrial protective coatings, trucks, coking, and steel making should be considered as the key sources for continuous emission reduction throughout the year in the Beijing-Tianjin-Hebei region (BTH). Non-road, oil refining, glass manufacturing and catering sources should be strengthened in summer, while biomass burning, pharmaceutical manufacturing, oil storage and transportation, and synthetic resin need more emphasis in other seasons. The multi-model validated result can provide scientific guidance for more accurate and efficient VOCs reduction., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

With the continuous abatement of industries and vehicles in the past years in China, the comprehensive understanding and scientific control of non-road construction equipment (NRCE) may play an important role in alleviating PM 2.5 and O 3 pollution in the next stage. In this study, the emission rates of CO, HC, NOx, PM 2.5 , CO 2 and the component profiles of HC and PM 2.5 from 3 loaders, 8 excavators and 4 forklifts under different operating conditions were tested for a systematic representation of NRCE emission characteristics. With the fusion of field tests, construction land types and population distributions, the NRCE emission inventory with a 0.1° × 0.1° resolution in nationwide and with a 0.01° × 0.01° resolution in Beijing-Tianjin-Hebei region (BTH) were established. The sample testing results suggested prominent differences in instantaneous emission rates and the composition characteristics among different equipment and under different operating modes. Generally, for NRCE, the dominant components are OC and EC for PM 2.5 , and HC and olefin for OVOC. Especially, the proportion of olefins in idling mode is much higher than that in working mode. The measurement-based emission factors of various equipment exceeded the Stage III standard to varying degrees. The high-resolution emission inventory suggested that highly developed central and eastern areas, represented by BTH, showed the most prominent emissions in China. This study is a systematic representations of China's NRCE emissions, and the NRCE emission inventory establishment method with multiple data fusion has important methodological reference value for other emission sources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Direct membrane filtration (DMF) technology achieves energy self-sufficiency through carbon recovery and utilization from municipal wastewater. To control its severe membrane fouling and improve DMF technology, targeted research on fouling behaviour and mechanisms is essential. In this study, a DMF reactor equipped with a flat-sheet ceramic membrane was conducted under three scenarios: without control, with intermittent aeration, and with periodic backwash. This system achieved efficient carbon concentration with chemical oxygen demand below 50 mg/L in permeate. Membrane fouling was dominated by intermediate blocking and cake filtration. And reversible external resistance accounted for over 85 % of total resistance. Predominant membrane foulants were free proteins, whose deposition underlies the attachment of cells and biopolymers. Backwash decreased the fouling rate and increased fouling layer porosity by indiscriminately detaching foulants from the membrane surface. While aeration enhanced the back transport of large particles and microbial activity, causing a relatively thin and dense fouling layer containing more microorganisms and β-d-glucopyranose polysaccharides, which implies a higher biofouling potential during long-term operation. In addition, aeration combined with backwash enhanced fouling control fivefold over either one alone. Therefore, simultaneous operation of backwash and other mechanical methods that can provide shear without stimulating aerobic microbial activity is a preferred strategy for minimizing membrane fouling during DMF of municipal wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Co-coagulation flotation (CCF) is a novel flotation technology that renders more efficient algal removal compared to traditional mechanical coagulation flotation (MCF) due to a short residence time (< 30 s) and fast rising behavior of algal flocs (> 250 m·h -1 ). This study compared the algal removal performance using continuous CCF and MCF using water samples taken from Lake Dianchi with severe Microcystis aeruginosa blooms. Removal efficiency, dosage of coagulant/flocculant, rising velocity and structural characteristics of the resulting flocs in the two processes were systematically compared. The results show that CCF could save >50 % polyaluminum chloride (PAC) and polyacrylamide (PAM) compared with MCF when the removal efficiency was both over 95 %. The average rising velocity of flocs in CCF could reach 254.3 m·h -1 , much higher than that in MCF (154.5 m·h -1 ). In the respective optimal coagulation conditions, the flocs formed in CCF (G = 164.8 s -1 ) were larger (1843 ± 128 μm) and more spherical with a higher fractal dimension (D f = 1.85 ± 0.01) than those generated in MCF (G = 34.1 s -1 ). The Stokes's Law was found to correctly predict the rising velocity of spherical flocs with large fractal dimensions (D f > 1.7). In contrast, the Haarhoff and Edzwald's extended equation was more suitable for calculating the rising velocity of irregular flocs with small fractal dimension. This study provides new insights into the mechanisms of the enhanced algal removal by CCF and lays foundation for developing cost-efficient algal mitigation processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

As treatments for mainstream pollutants in coal-fired power plants have been established, the control of non-conventional pollutants, such as SO 3 and HCl, is gradually gaining attention. In this study, combined SO 3 and HCl removal is proposed based on SO 3 removal by absorber injection. However, it is challenging to selectively absorb SO 3 and HCl from SO 2 -rich atmospheres. Therefore, Ca(OH) 2 was modified via ball milling and doping with CuO for the combined removal of SO 3 and HCl. The results showed that ball milling reduced the particle and grain sizes of Ca(OH) 2 , which increased the active sites of Ca(OH) 2 and prolonged reaction time. After modification by ball milling, SO 3 absorption per mg of Ca(OH) 2 increased by 40 %. However, HCl removal efficiency was difficult to improve by modifying Ca(OH) 2 using only ball milling under SO 3 and SO 2 atmospheres. Therefore, the dechlorination capacity of Ca(OH) 2 was improved by adding ions during the ball milling process. Doping of Ca(OH) 2 with Cu 2+ changed its crystal structure, weakened the diffusion resistance of HCl, and improved Ca(OH) 2 utilization. Additionally, it increased the energy of Ca(OH) 2 to adsorb HCl., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Heavy-duty diesel trucks (HDDTs) cause serious pollution to urban and regional environment. Understanding the spatiotemporal pattern of pollution emissions and its impact factors is the basis for implementing emission reduction measures. However, since the multiscale emission inventory of HDDTs is not currently established, multiscale analysis of these issues is still lacking. Therefore, this study uses massive trajectory data, detailed vehicle specification information and road network information, combined with localized emission factors, to construct a multiscale NO x emission inventory of HDDTs with high spatiotemporal resolution in the Beijing-Tianjin-Hebei region. Then the multiscale spatiotemporal variations of NO x emissions are analyzed by using spatial statistical indicators and multiscale geographical weighted regression model. The results show that the NO x emissions of HDDTs show different spatiotemporal distribution and aggregation characteristics at different scales. Specifically, link-scale emissions are concentrated to a few highways and are dominated by Low-Low cluster. While county-scale and city-scale emissions are concentrated in the eastern plains, mainly in High-High and Low-Low clusters. There are spatial heterogeneity and multiscale effects of socioeconomic and road attribute characteristics on the NO x emissions from HDDTs. Population density, urbanization rate, proportion of second industry, and proportion of highway affect the NO x emissions of HDDTs globally, while per capita GDP and road density have local effects. Our results extend the scientific understanding of the multiscale spatiotemporal variations of HDDTs and may provide a scientific basis for the development of targeted emission control measures for HDDTs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Nutrient imbalance (i.e., deficiency and toxicity) of microelements is an outstanding environmental issue that influences each aspect of ecosystems. Although the crucial roles of microelements in entire lifecycle of plants have been widely acknowledged, the effective control of microelements is still neglected due to the narrow safe margins. Selenium (Se) is an essential element for humans and animals. Although it is not believed to be indispensable for plants, many literatures have reported the significance of Se in terms of the uptake, accumulation, and detoxification of essential microelements in plants. However, most papers only concerned on the antagonistic effect of Se on metal elements in plants and ignored the underlying mechanisms. There is still a lack of systematic review articles to summarize the comprehensive knowledge on the connections between Se and microelements in plants. In this review, we conclude the bidirectional effects of Se on micronutrients in plants, including iron, zinc, copper, manganese, nickel, molybdenum, sodium, chlorine, and boron. The regulatory mechanisms of Se on these micronutrients are also analyzed. Moreover, we further emphasize the role of Se in alleviating element toxicity and adjusting the concentration of micronutrients in plants by altering the soil conditions (e.g., adsorption, pH, and organic matter), promoting microbial activity, participating in vital physiological and metabolic processes, generating element competition, stimulating metal chelation, organelle compartmentalization, and sequestration, improving the antioxidant defense system, and controlling related genes involved in transportation and tolerance. Based on the current understanding of the interaction between Se and these essential elements, future directions for research are suggested., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

The rapid industrialization has contributed to the miracle of economic growth in China, while also caused a series of environmental problems. As one of the most concerning urban disease in China, the aggravation of haze pollution is closely related to the accelerating urbanization and industrialization process in recent years, and the strong spatial diffusion makes the negative externality of haze pollution more harmful. This characteristic of haze pollution is closely related to the spatial structure of industrial sectors, especially the agglomeration of industrial sectors. This paper established a spatial economic framework to investigate the spillover effect of industrial agglomeration on haze pollution based on satellite raster map data of PM 2.5 and location entropy index, and further discuss the question that whether industrial agglomeration can achieve a balanced development for both economic growth and environmental quality. The results indicated that there is an inverted U-shaped relationship between industrial agglomeration and haze pollution, and the indirect effect from spatial spillover dominated this impact. Industrial agglomeration has a single threshold effect on the knowledge spillover and the utilization of pollution disposal infrastructure of industrial sectors. Only when the agglomeration level reaches the threshold value, the scale effect can be realized to promote the air quality. The resource allocation efficiency and knowledge spillovers of industrial agglomeration need to be promoted in order to reach the inflection point and realize the win-win situation., Competing Interests: Declaration of competing interest We confirm that no conflict of interest exists in the submission of this manuscript (Industrial Agglomeration and Haze Pollution: Evidence from China), and manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described is original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Excess heavy metals, especially copper (Cu) and cadmium (Cd), are common in paddy soils in the red soil hilly areas of southern China. Microorganisms are regulators of soil organic matter accumulation and pollutant transformation. Clarifying the effects of Cu and Cd accumulation on microbial community composition and function is a prerequisite for bioremediation of paddy soil contamination. However, it remains unclear how Cu and Cd contamination affects soil fungal taxonomic attributes and microbial-mediated biogeochemical processes in paddy soils. Here, soil heavy metals, fungal community composition, and soil enzyme activities were determined in paddy fields downstream of a typical mining area in southern China, and the effects of Cu and Cd co-contamination on fungal community diversity and co-occurrence networks, as well as the associations between them were assessed. The concentrations of Cu and Cd in paddy soils decreased from upstream to downstream of the river, and were positively correlated with the Shannon index of fungal communities. Soil Cu and Cd concentrations exhibited a greater impact on the structure and assembly of fungal communities than soil general properties. Increases in soil Cu and Cd concentrations were correlated with drastic changes in the cumulative relative abundance of ecological clusters in fungal co-occurrence networks. Soil Cu and Cd concentrations were positively correlated with the relative abundances of Eurotiomycetes, Pezizomycetes, Ustilaginomycetes, and Kickxellomycetes, respectively, whereas negatively correlated with hydrolase activities related to carbon, nitrogen, and phosphorus cycles. These results confirmed in the field that long-term Cu and Cd enrichment significantly altered the structure and diversity of fungal communities in the subtropical paddy soils, thereby affecting soil nutrient transformation and organic matter accumulation. This can also provide a basis for the bioremediation of heavy metal pollution in paddy soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Nickel resources are abundant in the world, and the application of nickel in production and life is more and more extensive. However, excessive nickel entering the environment will not only cause environmental pollution but also seriously endanger plants, animals and human health. Nickel compounds are carcinogenic and have been classified as a class 1 carcinogen. Nickel mainly exists in the form of divalent ions in the environment. However, there are few simple and effective methods for the detection of nickel ions, and these methods still have certain limitations. At present, the mechanisms of nickel influence in organisms are also unclear. Therefore, we constructed a ratiometric fluorescent probe Ra-Ni, which can achieve its own self-calibration and avoid the interference of other factors, thereby realizing the specific identification of nickel ions. The probe can detect nickel ions sensitively with a detection limit as low as 26.2 nM and can respond in a short time (< 2 min), which proves the great potential of the probe in the detection of nickel ions. At the same time, Ra-Ni has also been successfully used for imaging nickel ions in living cells and zebrafish, providing an effective tool for the study of physiological and pathological processes. The detection effect of nickel ions in actual water sample is also satisfactory, which further demonstrates the practicability of Ra-Ni in environmental applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Currently, the characteristics of volatile organic compounds (VOC) released from coking industry are still vague, and the widely used VOC emission factors (EFs) were still from the measurements of 1990s. Hence, focusing on coking industry, we conducted an in-situ measurement campaign in several typical plants, developed a set of VOC EFs for various release units, and estimated the current emission amounts and future reduction potentials of VOC in China. The measurements show that the levels of VOC in stationary units were 63.82-9563.93 μg·m -3 , and those surrounding fugitive units were 111.37-1436.36 μg·m -3 . VOC emissions from stationary units were directly calculated, which deducing EFs of 11.57, 15.51, 127.13, 0.28, 0.16 g·t -1 coke respectively for coke charging, coke pushing, coke oven chimney, dry quenching, and wastewater treatment processes. Meanwhile, VOC emissions from fugitive units were simulated following the inverse dispersion method, which achieving EFs of 443.34 ± 66.31, 352.12 ± 65.81, and 718.56 ± 132.69 g·t -1 coke respectively for the coke oven leakage, byproduct recovery with VOC treatment system, and byproduct recovery without VOC treatment system. Generally, the coking plants installing VOC treatment system had total VOC EF of 953.76 g·t -1 coke, about 37.1% lower than those never considering VOC treatment (1516.25 g·t -1 coke). According to these developed EFs, the VOC emission amount from coking industry in China were estimated, slightly decreasing from 623.54 to 578.17 Gg per year, although the coke production increasing from 410.86 to 418.26 Tg during 2015-2019. In future, according to the national industrial policies, regulations and standards, technical guidelines, the VOC reduction potential of this industry in China could reach 336.9 Gg, to which headstream adjustment, process improvement, and end-of-pipe control contributed about 21.4%, 31.6%, and 47.0%, respectively., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A better understanding of the physicochemical properties and fate of algae-derived organic matter (AOM) in water treatments significantly benefits the control of algae-derived disinfection byprodcuts and process parameter optimization. In this study, we conducted a comprehensive investigation of the release and treatability of dissolved organic matter during prechlorination and postcoagulation treatments of cyanobacteria-laden source water via size-exclusion chromatography-tandem diode array detector, fluorescence detector and organic carbon detector. The results revealed that the allochthonous humic substances could protect algal cell membrane from damage during prechlorination at a low level of chlorine dose. Due to the release and oxidation of biopterins during prechlorination of M. aeruginosa cells, the variation of the humic-like fluorescence can be used to indicate the chlorine dose for a sufficient membrane damage of algae cells. The prechlorination of M. aeruginosa cells induced minimal release of large MW biopolymer fractions but much more release of low MW fractions E1 and E2 (i.e., unknown carbonaceous substances and fluorescent nitrogenous biopterins). The physically extracted AOM contained a large proportion of biopolymers and could not well represent those released during prechlorination treatment. During coagulation, the negative effect of humic substances on the coagulant demand to achieve algae removal was more remarkable than AOM released by prechlorination. The high-MW biopolymers and humic substances can be removed over 50% by coagulation. Among the low-MW carbonaceous fractions, E1 released by prechlorination can also be effectively removed via coagulation while fractions C, D (possibly oligopeptides or secondary aromatic metabolites & low MW acids) and nitrogenous biopterins were recalcitrant to coagulation. This study highlights the differences of AOM properties between physical extraction and prechlorination and provides a basis for drinking water treatment plants to give more attention to the recalcitrant low MW fractions in coagulation when treating algae-laden source water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The deposition of phosphorus-based mineral solids in urine diversion systems has been one of the main challenges for the large-scale practical applications of urine source separation. Accurate rheological characterization of urine slurry is of high importance for its practical flow performance. The rheological data of urine slurry was obtained using a narrow gap rotating rheometer. Based on current pipe flow theories and the obtained rheological data of urine slurry, the transition velocity was determined. The impacts of solid concentration and temperature on the rheological behavior of urine slurry were investigated in this study. Urine slurry behaved as a Newtonian fluid at low solid concentration. By contrast, urine slurry changed from Newtonian to non-Newtonian fluid with the increase in solid concentration, demonstrating a shearing thinning behavior and yielding stress fluid. The impact of temperature on the apparent viscosity of the urine slurry was described using an Arrhenius-type function. Moreover, the impact of solid concentration and temperature on the transition velocity was quantified, which indicated that the non-Newtonian behavior of the urine slurry in the compression settling region has a significant impact on the pipe flow behavior, leading to the formation of a compressed layer on the bottom of the pipe. The targeting understanding of transition velocity is particularly useful for the practical design and optimization of urine piping system, especially on how to mitigate pipe blockages. Based on the evaluation of different piping systems, this work proposed several potential urine collection and transportation modes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Beijing-Tianjin-Hebei and the surrounding area (BTHSA) shows the poorest air quality in China, reflected in sub-standard PM 2.5 and increasingly pronounced O 3 pollution, stressing the urgency for regional cooperation and collaborative control of PM 2.5 and O 3 . With the aim to explore the cooperative regions and response mechanisms of PM 2.5 and O 3 in BTHSA, this study applied multiple mathematical models and analytical indicators to multiple data sources, including applying self-organizing map (SOM), response surface model (RSM), random forest (RF), distributed lag nonlinear models (DLNMs), and meta-analysis, on ground observations of air quality and meteorology, ozone monitoring instrument (OMI) observations, and air pollutant emission inventory. The results revealed that BTHSA exhibited clear regional characteristics of air pollution and can be divided into four clusters for enhanced intercity cooperation. Over 2015-2020, anthropogenic factors played more important roles than meteorological ones on the alleviation of PM 2.5 and the deterioration of O 3 . RSM based on observations and RF based on emissions both suggested that, in the near future, strengthened abatement of SO 2 , PM 2.5 and VOC can be beneficial for controlling PM 2.5 and O 3 pollution, while intensive NOx reduction in PM 2.5 -dominant months and mitigatory NOx reduction in O 3 -dominant months should be formulated before certifying an obvious transition of O 3 -NOx-VOC sensitivity. This study, with multi-model and multi-data fusion, can be expected to provide synthesized fact- and science-based guidance for the next-stage collaborative control of PM 2.5 and O 3 in BTHSA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Facing the elevated surface summer O 3 over North China in recent years with the continuous NO x reduction, we conducted the ozone-precursor sensitivity study in summer (July) in Beijing-Tianjin-Hebei region (BTH) under the 2018 and 2014 emissions, based on WRF-Chem model. On 2018 emission condition, 30% precursor reduction simulations presented the positive contribution of VOCs and the negative contribution of NO x to daytime O 3 . The occurrence probabilities of VOCs-sensitive, NO x -titration, mixed sensitive, NO x -sensitive, and non-sensitive regimes respectively reached 3-49%, 2-82%, 0-7%, 0-6% and 14-82% in the urban grids, and 2-32%,1-19%, 1-6%, 0-5% and 54-86% in the rural grids. For several widely used photochemical indicators, their values in VOCs-sensitive regime were well separated from those in NO x -sensitive regime, but the NO x -sensitive values were very similar to the non-sensitive values, which implied the inefficiency of these indicators in indicating NO x -sensitive regime. Finally, VOCs-sensitive regime was discerned based on the indicator HCHO/NO 2 , occupying about a third of areas in morning and dusk but shrinking to about a tenth of areas in 11:00-16:00 in BTH. And these areas apparently decreased from 2014 emission to 2018 emission. However, the rest areas of this region were under non-sensitive regime but not NO x -sensitive regime, for the noticeable O 3 drop never happened in NO x reduction scenario. Meanwhile, the modeled O 3 /PAN in the areas under non-sensitive regime exceeded 60, which also implied the minor impact of local photochemistry on O 3 there. Additionally, the responses of daytime O 3 to precursor emissions in the urban grids were calculated, declining by 20.8% for NO x and 6.9% for VOCs from 2014 to 2018. Therefore, to solve the ozone pollution problem of BTH, the cross-region strategy coupled with the VOCs and NO x co-control will be essential., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Lake clarity, usually measured by Secchi disc depth (SDD), is a reliable proxy of lakes trophic status due to its close link with total suspended matter, chlorophyll-a, and nutrients. Trained with in-situ measured SDD and match-up Landsat images, we established various regression models to estimate SDD for global lakes. We selected a unified model which demonstrated good spatiotemporal transferability, and has potential to map SDD in different years with good quality of Landsat top-of-atmosphere (TOA) images embedded in Google Earth Engine (GEE). The unified model was successfully calibrated (n = 3586 data points, R 2  = 0.84, MAPE = 29.8%) against SDD measured in 2235 lakes across the world, and the validation (n = 1779, R 2  = 0.76, MAPE = 38.8%) also exhibited stable performance. The unified model was tuned to historical SDD measurements coincident with different Landsat sensors (L5-TM, L7-ETM+, L8-OLI) launched over the past four decades (1984-2020), thus confirming its temporal stability. Global SDD was mapped using GEE with OLI TOA products mainly acquired in 2019 to examine the spatial variation of lake water clarity (lake surface area ≥ 1 ha) all over the world. Worldwide, lake water clarity averaged 3.13 ± 1.71 m in 2019, but exhibited remarkable spatial variability due to catchment hydrological and landscape settings, lake morphology, elevation and anthropogenic impact. Inland waters in Europe (4.18 ± 1.82 m) and North America (3.84 ± 1.77 m) had the highest clarity due to greater water depth combined with less human disturbance in the high latitude regions. Lakes in South America (2.50 ± 2.33 m), Asia (2.44 ± 1.63 m) and Africa (2.36 ± 0.72 m) displayed intermediate clarity. Lakes in Oceania (1.97 ± 1.48 m) exhibited the lowest clarity for all continents except Antarctica. Further, we used the mapped SDD to evaluate water trophic status using the Carlson trophic state index. Our results indicate that, in 2019, about 63.6% of the lake areas and 47.8% of total lake numbers (2,219,627/4,646,056) were oligotrophic for global lakes, while about 23.6% areal percent and 37.1% of lake numbers are eutrophic mostly as a result of their being located in agricultural and urban-dominated drainage basins. This study, for the first time, provides water clarity information for lakes with area ≥ 1 ha all over the world with 30-m resolution and facilitates the understanding of the water clarity relevant to TSM (r = 0.95), Chl-a (r = 0.73), total phosphorus (r = 0.75), total nitrogen (r = 0.60), which could further provide water clarity data and technical support for trophic level evaluations as well. This unified model could serve as a powerful research tool for long-term monitoring of aquatic ecosystems and assessing their resilience to anthropogenic disturbance and climate change-related stressors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Fenton-like catalysts represent a family of promising materials to degrade micropollutants from contaminated water. However, the practical applications of Fenton-like catalysts are mainly limited by low catalytic degradation efficiency and stability. Herein, for the first time, rapid fabrication of Ag-decorated Fe 3 O 4 /polydopamine (FPA) microspheres was achieved via the help of UV irradiation, and the designed FPA microspheres were employed as Fenton-like catalysts to degrade micropollutants. Results showed that UV irradiation could activate the generation of the polydopamine shell and accelerate the Ag deposition, which played a crucial role in the rapid synthesis of highly active and stable FPA catalysts. Relative to reported catalysts, these FPA microspheres exhibited outstanding catalytic degradation performance, achieving 94.38% removal of tetracycline within 60 min. This work will provide a convenient strategy in the sustainable and efficient purification of wastewater to improve the quality of human life., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

To effectively reduce the compound pollution of fine particulate matter (PM 2.5 ) and ozone (O 3 ), volatile organic compound (VOC) emission sources are being extensively studied. Studies on VOC emission characteristics have mainly focused on solvent-using and technological sources, while research on the combustion processes of high-energy-consuming industries remains limited. Here, we investigate the emission characteristics of 102 VOC species emitted from eight sources (sintering, pelletizing, steel smelting, a coke oven chimney, the topside of a coke oven, thermal power, and two types of cement kilns) used in four types of high-energy-consuming industries. Our results show significant differences among these sources. The average VOC mass concentrations varied from 0.14 to 7.08 mg/m 3 . Alkanes had the highest percentage contribution to VOCs from sintering (45.9%) and thermal power (44.6%), while aromatics had the highest percentage contribution from steel smelting (47.8%) and the topside of the coke oven (52.9%). Alkenes were abundant in the coke oven chimney (49.1%), and oxygenated VOCs accounted for 65.3% of the total VOCs from pelletizing. We also observed notable differences between the two types of cement kilns. In general, ethane, ethene, benzene, propane, acetaldehyde, and chloromethane were the dominant VOC species in all sources. The differences between the sources were due to factors such as the applied raw materials, calcination temperature, and end-of-pipe treatment. By reviewing studies from the past 20 years, we found that differences in the number of VOC species and the implementation of ultra-low emissions affect VOC emission characteristics. The coke oven chimney and cement kiln chimney-1 had the highest ozone formation potential and secondary organic aerosol potential, respectively. The VOC emissions from coking, iron and steel, thermal power, and cement industries were 1162.1, 289.9, 311.0, and 470.2 Gg, respectively. Our results highlight the need for more effective control measures to minimize VOC emissions from high-energy-consuming industries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Nitrite is a highly toxic and pathogenic pollutant that is widely distributed in various nitrogenous wastewaters. Therefore, there is an urgent need for fast and stable nitrite detection to avoid water pollution and protect human health. In this study, we developed a novel rapidly preparable and easily maintainable biocathode electrochemical biosensor (BEB) using nitrite-reducing bacteria as the detectors to realize continuous nitrite monitoring in wastewater. The preparation of the biocathode was shortened by the polarity inversion method to less than 6 d. The BEB could detect nitrite solution samples in the range of 0.1- 16.0 mg NO 2 - -N L -1 within 1.7 min. The BEB was also successfully used to detect nitrite in real wastewater with a relative error < 4.0% and a relative standard deviation < 5.8%. In addition, the BEB could be easily maintained by an operation mode of microbial fuel cells and stably detected nitrite for at least 150 tests. Our study provided a feasible and convenient way to develop electrochemical biosensors based on the biocathode for continuous and stable monitoring of pollutants in wastewater., Competing Interests: Declaration of competing interest There are no conflicts of interest to declare., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Foam flotation is an economical and efficient technology for microalgae harvesting. However, the mechanism of cell-collector-bubble interfacial interactions remains to be elucidated. There are two distinct hypotheses regarding the mechanism of microalgae foam flotation. In this study, the cationic surfactant N-cetyl-N-N-N-trimethylammonium bromide (CTAB), which acts as a partition between Chlorella sorokiniana cells and bubbles, is quantified and the zeta potential response of cells and bubbles after adsorption of CTAB is calculated to reveal the interfacial mechanism of the cells-collector-bubble interfacial interactions. The results indicated that more than 90% of CTAB was preferentially adsorbed on the bubbles, which reversed the surface charge of bubbles from negative (-20 mV) to positive (6.1 mV). However, only 0%-3% CTAB was observed on the microalgae cells, suggesting its limited influence on the negatively charged microalgae cells (from -22.3 to -18.6 mV). During microalgae foam flotation, the nonpolar tails of CTAB were first inserted into the bubble through hydrophobic interactions, leaving the positively charged polar heads outside; further, the CTAB-covered positively charged bubbles captured the negatively charged cells by electrostatic attraction. A feasible mechanism was proposed to understand the interfacial interaction of the microalgae cell-CTAB-bubble. By understanding the mechanism of foam flotation, efficient and cost-effective collectors and devices for microalgae harvesting using foam flotation can be developed., Competing Interests: Declaration of competing interest The authors declare no conflict of interests., (Copyright © 2021. Published by Elsevier B.V.)

Biochar-supported metallic oxides are attractive adsorbents for heavy metal cleanup, but the adsorption performance is still unsatisfactory as a result of the self-aggregation of the incorporated metallic oxides. A new hybrid nano-material was prepared through impregnating hydrated ferric oxide (HFO) nanoparticles within biochar bearing high-density charged oxygen-containing groups (e.g., carboxyl and hydroxyl groups) (ABC) derived from HNO 3 treatment. The as-made adsorbent, denoted as HFO-ABC, possesses highly dispersed HFO nanoparticles with typical size lower than 20 nm, and exhibits greater sorption capacity for Cd(II) and Cu(II) than the pristine biochar-supported HFO. It also shows great sorption preference toward Cd(II) and Cu(II) in co-presence of high levels of Ca 2+ , Mg 2+ and humic acid (HA). Such prominent performance is put down to the high-density charged functional groups on the host ABC, which not only promote the dispersion of the immobilized HFO nanoparticles but also generate the potential Donnan membrane effect, i.e., the pre-concentration and permeation of target metals prior to their preferable adsorption by nano-HFO. The predicted effective coefficients of intra-particle diffusion for Cu(II) and Cd(II) are 3.83 × 10 -9 and 4.33 × 10 -9 cm 2 /s, respectively. HFO-ABC exhibits excellent performance for fixed-bed column application, and yields 513 and 990 BV effluents for Cd(II) and Cu(II) to achieve their discharge standards, respectively. The spent HFO-ABC could be in situ regenerated using binary HCl-CaCl 2 solution with desorption efficiency higher than 95%. All results manifest that increasing charged functional groups via HNO 3 treatment is an effective measure for boosting sorption performance of biochar-based nanocomposites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

Marine aerosols are believed to have an organic surface coating on which fatty acids act as an important component due to their high surface activity. In addition, various kinds of enzyme species are abundantly found in seawater, some of which have been identified to exist in marine aerosols. Herein, from the perspective of marine aerosol interface simulation, we investigate the effect of Burkholderia cepacia lipase on the surface properties of stearic acid (SA) monolayer at the air-water interface by using surface-sensitive techniques of Langmuir trough and Infrared reflection-absorption spectroscopy (IRRAS). Our findings indicate that the stearic acid film undergoes a significant expansion, especially when the lipase concentration is 500 nM, because of the incorporation of lipase as observed from the surface pressure-area (π-A) isotherms. IRRAS spectra also show reduced intensities and ordering in the methylene stretching vibration region of stearic acid as a result of low surface density and disordered packing as the enzyme concentration increases. In particular, when the concentration of lipase is 500 nM, the lowest I as /I s values are shown on both pure water subphase and artificial seawater subphase, indicating more gauche conformations for SA. Furthermore, SA films with lipase incorporation were also studied at three different pH of subphase environment, considering the decrease of pH caused by the reaction with acidic gases during the aerosol aging process. The results reflect a more pronounced expansion of SA monolayer in acidic environment at pH 2.5, suggesting that hydrophobic interaction plays an important role in the disorder of the SA monolayer. In view of the coexistence of fatty acids and enzymes in the marine environment, this study provides a further understanding of the surface organization and behavior of organic-coated marine aerosols and deepen the knowledge of lipid-enzyme interfacial interactions occurring in the atmosphere., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The affinity of biochar (BC) adsorbing phosphate was weak, while generation of magnesium oxide (MgO)-BC nanocomposites that transformed the crystal structures of BC would change the adsorption processes in improving the phosphate adsorption. Hereon, four different crystal structure of absorbents were selected to illustrate why the crystal structures and surface properties of absorbents were of great importance for the phosphate adsorption. The results showed that MgO/KBC with higher combination degree between MgO and KBC could change the normal crystal structure (MgO/KBC1, MgO phase (dominant)) to C-Mg-O phase (dominant). Therefore, MgO/KBC could achieve highest adsorption rate (k 2 , 8.059 g mg -1  min -1 ) and q m (maximal adsorption capacity, 121.950 mg g -1 ) for phosphate adsorption among absorbents, and even it had high anti-interference capacity for anions and natural organic matter (NOM). The mechanisms of MgO/KBC for phosphate adsorption were hydrogen-bond interaction, inner-sphere complexation and surface chemical adsorption; adsorption of phosphate on MgO/KBC1 was mainly controlled by inner-sphere complexation (Mg-O-PO 3 H 2- , Mg-O-PO 3 H 2 - species). In addition, the adsorbability of MgO/KBC for phosphate could be restored after recalcination, which further proved that an efficient nanocomposite, calcinated from waste biomass (fallen leaves), was proposed to control eutrophication., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this study, the feasibility of free nitrous acid (FNA) pretreatment coupled with quorum sensing (QS) was investigated to enhance hydrogen recovery from waste activated sludge (WAS) via electro-fermentation (EF). 3-oxo-hexanoyl-homoserine lactone (3OC6-HSL), as the signal molecule, was only added in the first three cycles of sludge inoculation at the phase of microbial electrolysis cells (MECs) startup. Results showed that QS combined FNA (AHL-FMEC) enabled highest hydrogen yield and current (4.3 mg/g VSS and 4.5 mA), while that generated from sole FNA/QS treated WAS (FMEC/AHL-RMEC) were only 3.5/3.0 mg/g VSS and 1.5/1.5 mA, respectively. Fourier transform infrared (FT-IR) spectra illustrated the effective conversion of organics in AHL-FMEC, the utilization efficiencies of proteins and carbohydrates achieved to 75.0% and 79.7%, respectively. Besides, the internal resistance decreased from 34.5 Ω (FMEC) to 22.9 Ω (AHL-RMEC), further to 18.0 Ω, indicating the promoted bioelectrochemical activity of electroactive bacteria (EAB) in AHL-FMEC. Correspondingly, both EAB (21.7%), e.g., Geobacter (9.3%) and Pseudomonas (3.2%) and anaerobic fermentation bacteria (AFB, 28.6%), e.g., Proteiniclasticum (14.2%) and Petrimonas (3.6%) enriched to peaks in AHL-FMEC. Moreover, molecular ecological network (MEN) analysis revealed the underling relationships among AFB, EAB and homo-acetogen in EF system, suggesting the possible cooperative QS has been constructed. The results obtained in this study may provide a new insight for efficient hydrogen recovery from electro-fermentation of WAS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Bio-cathodic nitrate removal uses autotrophic nitrate-reducing bacteria as catalysts to realize the nitrate removal process and has been considered as a cost-effective way to remove nitrate contamination. However, the present bio-cathodic nitrate removal process has problems with long start-up time and low performance, which are urgently required to improve for its application. In this study, we investigated an anode-cathode polarity inversion method for rapidly cultivating high-performance nitrate-reducing bio-cathode by regulating bio-anodic bio-oxidation electroactivities under different external resistances and explored at the first time the correlation between the oxidation performance and the reduction performance of one mixed-bacteria bioelectrode. A high bio-electrochemical nitrate removal rate of 2.74 ± 0.03 gNO 3 - -N m -2 d -1 was obtained at the bioelectrode with high bio-anodic bio-oxidation electroactivity, which was 4.0 times that of 0.69 ± 0.03 gNO 3 - -N m -2 d -1 at the bioelectrode with low bio-oxidation electroactivity, and which was 1.3-7.9 times that of reported (0.35-2.04 gNO 3 - -N m -2 d -1 ). 16S rRNA gene sequences and bacterial biomass analysis showed higher bio-cathodic nitrate removal came from higher bacterial biomass of electrogenic bacteria and nitrate-reducing bacteria. A good linear correlation between the bio-cathodic nitrate removal performance and the reversed bio-anodic bio-oxidation electroactivity was presented and likely implied that electrogenic biofilm had either action as autotrophic nitrate reduction or promotion to the development of autotrophic nitrate removal system. This study provided a novel strategy not only to rapidly cultivate high-performance bio-cathode but also to possibly develop the bio-cathode with specific functions for substance synthesis and pollutant detection., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Dicarboxylic acids are a group of highly oxidized components, which can provide insights into the formation mechanism and aging process of secondary organic aerosols (SOA). Based on the 12-h day and night PM 2.5 samples collected in downtown Beijing in January, April, July and October of 2017, dicarboxylic acids and relevant components were measured to investigate their seasonal variation pattern and sources. High concentrations of the identified organic acids were observed, following the decreasing order of July > January > October > April. The high fractions of phthalic acid and maleic acid in January indicated severe aromatic SOA pollution during the sampling period in winter, and the high malonic acid to succinic acid and malic acid to succinic acid ratios in July suggested strong photochemical formation over the sampling period in summer. Based on the calculation of principle component analysis and multiple linear regression, water-soluble organic acids were mainly formed from the aerosol aging process during the sampling periods except for January, while water-soluble organic carbon (WSOC) mostly originated from combustion sources. Correlation analysis was conducted between the CO-normalized concentrations of organic acids and PM 2.5 , O 3 , as well as the meteorological parameters. The results suggested that gas-phase photooxidation contributed significantly to the formation of these organic acids during the entire sampling period, and the aqueous-phase process played an important role over the severe haze event in January. Our results also suggested that the intensity of photooxidation and the aging degree of SOA were enhanced along with the reduction of PM 2.5 in Beijing in recent years., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Here we present multiproxy inorganic geochemical records from a peat core (ZK5) from the Dajiuhu Basin in central China to investigate peatland deposition processes and atmospheric metal pollution and to explore their relationships with East Asian monsoon change and human activities in the Middle Yangtze Valley since 20,000 cal yr BP. The peat physicochemical data including total organic carbon (TOC), trace elements, and grain-size show that the site has changed from a lake during the cold-wet Last Glacial Maximum (LGM; 20,000-18,000 cal yr BP), to a marshy wetland during the mild last deglaciation (18,000-11,500 cal yr BP) and a peatland during the mostly warm and dry Holocene (11,500 cal yr BP-present). This general sequence corresponds with changes in East Asian monsoon indicated by stalagmites δ 18 O records and boreal summer insolation. Marked decreases in trace element concentrations correspond to two periods of peatland expansion during the abrupt hydroclimatic transitions from the LGM to the last deglaciation and from the last deglaciation to the early Holocene. Warm-dry mid-Holocene might induce high organic matter decomposition in peat sediments. Increasing natural element concentrations since the late Holocene are correlated with the weakening of the summer monsoon and elevated atmospheric dust deposition. Increasing Cu and Pb concentrations in peat record indicate large-scale Cu smelting during the Bronze Age and excessive coal burning during the 10th century or so. The anthropogenic heavy metals were transported by prevailing East Asian summer monsoon and deposited in the Dajiuhu Basin during periods of heightened human activities. Our compilation of heavy metals records across China confirmed the noticeable impacts of the historical human activity on deposition environments during the late Holocene. Consequently, trace elements from the Dajiuhu Basin are reliable proxies for capturing monsoon climate-induced peatland deposition response and present important evidence for a historical atmospheric heavy metal pollution in the Middle Yangtze Valley. Our results offer useful references for peatland evolution and protection under the background of global change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A simple and rapid method employing non-suppressed ion chromatography with electrospray ionization tandem mass spectrometry has been developed for the direct determination of trace-level haloacetic acids (HAAs) in water samples. Using 70/30 (v/v) acetonitrile/1 M aqueous methylamine as the mobile phase, three IC columns - AS16, AS18 and AS24 from Thermo-Scientific - were tested, respectively, with the AS16 column exhibiting the best overall performance with respect to resolution and retention time. To assess the effects of mobile phase composition on retention time of HAAs, the AS16 column was further tested using (i) different proportions of acetonitrile to aqueous methylamine, (ii) different proportions of acetonitrile to aqueous solution at fixed methylamine concentrations, and (iii) different concentrations of methylamine at fixed proportions of acetonitrile to aqueous solution. With a low proportion of aqueous solution, van der Waals and/or hydrogen-bonding interactions appeared to play an important role in governing HAA retention, i.e., HAAs with relatively higher apparent logK ow * caused by elevated solvent s s pK a exhibited longer retention times; whereas with a high proportion of aqueous solution, ionic interactions appeared to dominate retention of HAAs, with the more polarizable HAAs exhibiting longer retention times. Using 70/30 (v/v) acetonitrile/1 M aqueous methylamine, the method detection limits were in the range of 0.090-0.216 μg/L for the 11 selected chloro-, bromo- and iodoacetic acids. Finally, this method was applied to monitor HAAs yields in laboratory chlorination experiments and to determine concentrations of HAAs in tap water and wastewater effluent samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

A novel electrochemical oxidation-methanogenesis (EO-M) system was proposed for the first time to simultaneously achieve antibiotic degradation and a bioelectrochemical conversion of CO 2 to CH 4 with low energy costs. A dual-chamber system was installed with an antimony-doped tin oxide anode (Ti/SnO 2 -Sb) for the electrocatalytic generation of hydroxyl radicals to degrade ciprofloxacin (CIP), and a CO 2 -reducing methanogenic biocathode was enriched based on a three-dimensional (3D) graphitized granular activated carbon (GGAC) for microbial electromethanogenesis. The anode achieved removal efficiencies as high as 99.99% and 90.53% for CIP (14 mL, 50 mg L -1 ) and the chemical oxygen demand (COD, 89 mg L -1 ), respectively. The biocathode was rapidly enriched within 15 days and exhibited a methane production rate that stabilized at 15.12 ± 1.82 m 3  m -3 d -1 ; additionally, the cathodic coulombic efficiency reached 71.76 ± 17.24%. The energy consumption of CIP degradation was reduced by 3.03 Wh L -1 compared to that of a single electrochemical oxidation system due to the lower cathodic overpotential of CO 2 bioelectrochemical reduction in the EO-M system. A detailed analysis of the biofilm evolution in the 3D biocathode during the start-up process demonstrated that the enhanced absorption of extracellular polymeric substances by the GGAC cathode accelerated the enrichment of methanogens and induced the formation of methanogens with a large number of flagella. An analysis of the microbial community showed that a high relative abundance of Methanobacterium movens could promote a flagella-mediated direct electron transfer of the biocathode, eventually reducing the cathodic overpotential and energy costs of the EO-M system., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Source-separated urine is an attractive fertilizer due to its high nutrient content, but the rapidly hydrolysis of urea leads to ammonia volatilization and other environmental problems. Urine stabilization, which meanly means preventing enzymatic urea hydrolysis, receives increasing attention. Accordingly, this study developed a technique to stabilize fresh urine by heat-activated peroxydisulfate (PDS). The effect of three crucial parameters, including temperature (55, 62.5, and 70 °C), heat-activated time (1, 2, and 3 h), and PDS concentration (10, 30, and 50 mM) that affect the activation of PDS in urine stabilization were investigated. Nitrogen in fresh urine treated with 50 mM PDS at 62.5 °C for 3 h existed mainly in the form of urea for more than 22 days at 25 °C. Moreover, the stabilized urine could remain stable and resist second contamination by continuous and slow pH decrease due to PDS decomposition during storage. Less than 8% of nitrogen loss in stabilized urine was detected during the experiment. The investigation of nitrogen transformation pathway demonstrated that urea was decomposed into NH 4 + by heat-activated PDS and further oxidized to NO 2 - and NO 3 - . The nitrogen loss during treatment occurred via heat-driven ammonia volatilization and N 2 emission produced by synproportionation of NO 2 - and NH 4 + under acid and thermal conditions. Overall, this study investigated an efficient approach of urine stabilization to improve urine utilization in terms of nutrient recovery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

The quality of groundwater in a region is regarded as a function of natural and anthropogenic factors. Receptor models have advantages in source identification and source apportionment by testing the physicochemical properties of receptor samples and emission sources. In our study, receptor models PMF and PCA-APCS-MLR were developed to qualitatively identify the latent sources of groundwater pollution in the study area and quantitatively evaluate the contribution of each source to groundwater quality. The performances of PMF and APCS-MLR models were compared to test their applicability on the assessment of groundwater pollution sources. Results showed that both of the models identified five sources of groundwater contamination with similar main load species of each potential source. The comparable source apportionment of species NO 2 - and NO 3 - with two models indicated the reliable source estimation for these species, whereas the contributions of sources to species Fe, Mn, Cl - , SO 4 2- and NH 4 + were significantly different due to the large variability of data, difference of uncertainty analysis and algorithm of unexplained variability in the two models. R-squared value between observation and model prediction was 0.603-0.931 in PMF and 0.497-0.859 in PCA-APCS-MLR. The significant disagreement of average source contribution was detected in agricultural source and unexplained variability using PMF and PCA-APCS-MLR models. Average contributions of other sources to groundwater quality parameters had similar estimates between the two models. Higher R 2 and smaller proportion of unexplained variability in the PMF model suggested that PMF approach could provide more physically plausible source apportionment in the study area and a more realistic representation of groundwater pollution than solutions from PCA-APCS-MLR model. The study showed the advantages of application of multiple receptor models on achieving reliable source identification and apportionment, particularly, providing a better understanding of applicability of PMF and PCA-APCS-MLR models on the assessment of groundwater pollution sources., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In order to effectively monitor the residue of kanamycin (KAN), a dual-signal-amplified electrochemiluminescence (ECL) aptasensor based on multi-walled carbon nanotubes@titanium dioxide/thionine (MWCNTs@TiO 2 /Thi) was proposed. MWCNTs@TiO 2 with large specific surface area and favorable biocompatibility could accelerate charge transfer and enable high loading of luminol to enhance ECL response. As a perfect electronic mediator, Thi could also accelerate electron conductivity to further enhance ECL intensity. The ECL intensity of MWCNTs@TiO 2 /Thi was enhanced for 3.6-fold compared with that of individual Thi because Thi could strongly interact with MWCNTs through π-π stacking force to enhance the electronic transmission. With the outstanding electron transfer property of MWCNTs@TiO 2 and Thi, ECL intensity of the proposed aptasensor was obviously increased. Upon addition of KAN, the aptamer bound to its target, which caused that the ECL intensity decrease significantly. Therefore, KAN concentration could be monitored on the basis of signal intensity. Under optimal conditions, the constructed aptasensor exhibited a sensitive response towards KAN and a low detection limit of 0.049 ng mL -1 was obtained. It also possessed the excellent specificity, favorable stability and good reproducibility. Importantly, the application of proposed ECL aptasensor provides an efficient approach for highly sensitive detection of various small molecular contaminants., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Mercury is a key global pollutant, yet the mechanism by which mercury-exposure causes intestinal injury is not clear, we aimed to investigate the mechanism of intestinal injury and gut microbiota changes caused by mercury-exposure. Twelve Kunming mice were divided into two groups (n = 6), and the two groups were treated with 0 mg/L and 80 mg/L HgCl 2 in drinking water for 90 days respectively. Our results showed that mercury-exposure prominently effected body weight gain and glucose levels. The mercury-exposed mice showed intestinal injury, which was diagnosed by Histopathological Examination and Transmission Electron Microscopy. Meanwhile, RT-PCR indicated that mercury-exposure significantly increased the expression of pro-apoptotic genes including Bax, JNK, ASK1, caspase3 and TNF-α, and significantly decreased the expression of the anti-apoptotic gene Bcl-2. Furthermore, high-throughput sequencing analysis showed that at the genus level some microbial populations including Coprococcus, Oscillospira and Helicobacter were significantly increased whereas some microbial populations including Lgnatzschineria, Salinicoccus and Bacillus were significantly decreased. Moreover, PICRUSt analysis revealed potential metabolic changes. Correlation analysis indicated that microorganisms were significantly correlated with apoptotic gene expression. In summary, our results indicated that mercury-exposure affected the growth and development of mice, induced intestinal microbiota dysbiosis and metabolic disorder, and aggravated apoptosis in mice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)