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• Assess the contribution of ecological land structure in reducing PM 2.5 pollution. • The dust suppression efficiency of the ecological land composite structure is higher than that of the single structure. • There are significant differences in the role of different types of ecological land. • Compares the suitability of different models and the accuracy of the results. In the context of serious urban air pollution and limited land resources, it is important to understand the environmental value of ecological land. Previous studies focused mostly on the effectiveness of a particular type of green space or the total amount of ecological land on PM 2.5 and have rarely analyzed the association between ecological land structure and PM 2.5 systematically and quantitatively. Therefore, we took 277 cities in China as an example, comprehensively compared the results of different models, and selected a spatial Durbin model using time-fixed effects to dissect the degree of influence of ecological land and different land types within it on PM 2.5. The urban ecological land use structure was closely related to PM 2.5 , and the higher the proportion of ecological land use was, the lower the PM 2.5. The degree and direction of influence of different types of land functions within ecological land on PM 2.5 differed, with forests, shrubs, and grasslands causing a weakening impact on PM 2.5 , while wetlands and waters did not have a weakening role. The degree of reduction of PM 2.5 by a single type of ecological land was significantly smaller than that by a composite type of ecological land. Green space should be comprehensively considered, designed and adjusted in urban planning to continuously optimize the ecological spatial structure, increase landscape diversity and maximize ecological benefits. The findings of this study help with exploring the effects of land use structure under the goal-oriented control of air pollution and provide theoretical reference and decision-making support for formulating precise air pollution control policies and optimizing the spatial development of national land. [ABSTRACT FROM AUTHOR]

[Display omitted] • Prioritization of risks posed by chemicals manufactured in China is performed. • High risk potentials for some intermediates, materials and biocides are elucidated. • Fluorine substituted PBT and PMT substances are highlighted. • Conventional classes of insecticides are classified as being of high concern. • A set of PB&MT substances are identified and characterized. Over a third of the global chemical production and sales occurred in China, which make effective assessment and management for chemicals produced by China's chemical industry essential not just for China but for the world. Here, we systematical assessed the persistence (P), bioaccumulation (B), mobility (M) and toxicity (T) potency properties for the chemicals listed in Inventory of Existing Chemical Substances of China (IECSC) via experimental data retrieved from large scale databases and in silico data generated with well-established models. Potential PBT, PMT and PB&MT substances were identified. High risk potentials were highlighted for groups of synthetic intermediates, raw materials, as well as a series of biocides. The potential PBT and PMT synthetic intermediates and/or raw materials unique to the IECSC were dominated with organofluorines, for example, the intermediates used as electronic light-emitting materials. Meanwhile, the biocides unique to the IECSC were mainly organochlorines. Some conventional classes of insecticides, such as organochlorines and pyrethroids, were classified as being of high concern. We further identified a group of PB&MT substances that were considered to be both "bioaccumulative" and "mobile". Their properties and common substructures for several major clusters were characterized. The present results prioritized groups of substances with high potentials to cause adverse effects to the environment and humans, many of which have not yet been fully recognized. [ABSTRACT FROM AUTHOR]

The extensive use of colistin in swine production may have contributed to the recent emergence of corresponding mobile resistance gene mcr - 1. The use of colistin as a feed additive was banned in China in April 2017. To examine the occurrence of colistin and dissemination of mcr - 1 in swine feedlots before and after the colistin ban and effects of different manure treatments. Environmental samples were collected from swine feedlots before (December 2016) and after (December 2017) the colistin ban. Colistin concentrations were determined by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. The prevalence of mcr - 1 were determined by quantitative PCR analysis, while bacterial community composition was investigated by 16S rRNA sequencing. In 2016, colistin was detected in feed and fresh manure samples at 67 mg/kg and 17 mg/kg, respectively, but was absent from all samples in 2017. In 2016, the relative abundance of mcr - 1 in fresh manure was lower than that in solid samples after natural drying, while a higher relative abundance was detected in fresh manure samples compared with biogas slurry samples. A strong correlation between colistin concentration and relative abundance of mcr - 1 was observed in fresh manure. The samples collected in 2017 showed a lower relative abundance of mcr - 1 compared with those collected in 2016. Bacterial community analysis showed that the abundance of Enterobacteriaceae, which act as a vehicle and reservoir of mcr - 1 , increased with natural dying but decreased with anaerobic digestion. The presence of colistin exerts direct selection pressure for the accumulation of mcr - 1 in manure, while the ban on colistin likely halted the dissemination of mcr - 1 on pig farms. Anaerobic digestion is an effective waste treatment process for removing mcr - 1 , which might be mainly driven by the shift in bacterial community structure. • The presence of colistin exerts direct selection pressure for the accumulation of mcr-1 in swine feedlots. • The ban on the use of colistin as an animal feed additive helped decrease the prevalence of mcr-1 in pig farm environments. • Anaerobic digestion is an effective waste treatment process for removing mcr-1. [ABSTRACT FROM AUTHOR]

Evidence on whether an excess risk of incidence and mortality of cardiovascular disease (CVD) among people exposed to a high level of ambient PM 2.5 in low- and middle-income countries (LMICs) is lacking. This study aimed to investigate the associations between long-term exposure to ambient fine particulate matter<2.5 µm (PM 2.5) concentrations and the risk of incidence and mortality of CVD in a large cohort study from 115 communities. In this cohort study, we followed 42 160 adults aged 35–75 years at baseline who enrolled in the Prospective Urban and Rural Epidemiology Study conducted in China (PURE-China) between 2005 and 2009 with ambient PM 2.5 estimates, and followed up until August 2021. Cox proportional hazards frailty models were used to estimate the associations between long-term mean outdoor PM 2.5 concentrations and CVD events, CVD mortality, and all-cause mortality. During a median follow-up period of 11.8 years, we documented 2 190 deaths, including 732 CVD deaths. There were 4 559 (10.8 %) of 42 160 participants who experienced incident total CVD, among them there were 861 myocardial infarctions (MI) and 2 338 S. The 3-year median concentration of ambient PM 2.5 before the cohort commencement was 52.7 µg/m3 (interquartile range [IQR] 30.3–74.6). In full adjusted model, a 10 µg/m3 increase in PM 2.5 was associated with a hazard ratio (HR) of 1.12 (95 % CI 1.11–1.14) for major CVD and 1.03 (95 % CI 1.01–1.05) for all-cause mortality. Besides, long-term PM 2.5 concentrations had a significantly positive gradient association with total CVD and a similar pattern of associations with other CVD outcomes was observed. This study demonstrated that long-term ambient PM 2.5 concentrations is positively associated with increased risks of CVD in adults aged 35–70 years from China. This finding reinforces the need for policymakers to adopt more effective strategies to improve air quality. [ABSTRACT FROM AUTHOR]

• Arachidonic acid metabolism plays a role in platelet activation and oxidative stress. • Ozone exposure is associated with altered arachidonic acid metabolism. • Ozone is associated with increased platelet activation and systemic oxidative stress. • The findings shed lights on biological mechanisms of ozone cardiovascular effects. Ozone (O 3) exposure has been associated with biomarkers of platelet activation and oxidative stress. The metabolism of arachidonic acid (AA) plays an important role in platelet activation and oxidative stress. However, AA metabolic pathways have not been examined in relation to O 3 and other air pollutants. Early morning urine and fasting blood were longitudinally collected up to four times from 89 healthy adults (22–52 years old, 25 women) in Changsha City, China. We measured three urinary AA metabolites, namely 11-dehydro-Thromboxane B2 (11-dhTXB 2) produced from the arachidonic cyclooxygenase pathway, 20-hydroxyeicosatetraenoic acid (20-HETE) from the CYPs pathway, and 8-isoprostane from the non-enzymatic pathway. Urinary malondialdehyde (MDA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) were measured as indicators of oxidative damage to lipids and DNA, respectively. We measured soluble P-selectin (sCD62p) concentrations in plasma as an indicator of platelet activation. Indoor and outdoor air pollutants were measured and combined with participants' time-activity pattern to calculate personal exposure to O 3 , PM 2.5 , NO 2 , and SO 2 averaged over 12-hour, 24-hour, 1-week, and 2-week periods prior to biospecimen collection, respectively. Linear mixed-effects models were used to examine the relationships of AA metabolites with air pollutant exposures, plasma sCD62p, and urinary MDA & 8-OHdG. We found that a 10% increase in 12 h and 24 h O 3 exposure were associated with increases in urinary11-dhTXB 2 by 1.4% (95%, 0.1% to 2.6%) and 1.3% (0.05% to 2.5%), respectively. These associations remained robust after adjusting for co-pollutant exposures. No significant associations were observed between 11-dhTXB 2 and other pollutants or between O 3 exposures and other AA metabolites. All the three AA metabolites were significantly and positively associated with urinary MDA and 8-OHdG, whereas only urinary 11-dhTXB 2 was significantly and positively associated with plasma sCD62p. A metabolite of AA from the cyclooxygenase pathway was positively associated with short-term O 3 exposure, and with a plasma marker of platelet activation and two urinary markers of oxidative stress. The results suggest that O 3 exposure may contribute to increased platelet activation and oxidative damages via altering the metabolism of AA. [ABSTRACT FROM AUTHOR]

• Integrated farms had a greater number/abundance of ARG and MGE subtypes. • Integrated farms had higher abundance of colistin/tigecycline resistance genes. • Relationships among ARGs, MGEs, and microbial taxa were more complex in integrated farms. Cumulative research on resistomes and microbiomes from aquatic environments has revealed that both integrated freshwater and monoculture freshwater aquaculture systems can cause the development and dissemination of antibiotic resistance genes (ARGs) and associated mobile genetic elements (MGEs). However, few studies have examined differences in resistomes between the different aquaculture modes, and those that do have focused on antibiotic residues or individual resistance genes. In the current study, we collected 44 environmental samples from two monoculture freshwater aquaculture farms and four integrated farms (two duck and fish farms, two laying duck and fish farms) in Guangdong, China, in 2018. After measuring the concentrations of antibiotic residues in the samples, we characterized MGEs and ARGs and examined their association with potential bacterial hosts in the microbial communities using high-throughput sequencing-based metagenomic and network analyses. We then compared the resistome profiles of the different aquaculture models. We found that the number and total relative abundance of ARG and MGE subtypes in the integrated (fish and duck/laying duck) farm samples were significantly higher than those in samples from monoculture freshwater aquaculture farms. Specifically, both the mobile colistin resistance genes mcr variants and tigecycline resistance gene tet (X) variants in integrated farms exhibited higher total relative abundance than that in monoculture farms. Moreover, the interrelationships among ARGs and microbial taxa, ARGs and MGEs, and MGEs and microbial taxa in the integrated farm samples were also more complex than those observed in monoculture freshwater aquaculture farm samples. Meanwhile, the species of Acinetobacter and Escherichia were identified to be the possible host of tet (X) and ESBL gene bla CTX-M in aquaculture, respectively. To the best of our knowledge, this is the first metagenomic study to analyze differences in resistome profiles between integrated and monoculture ponds. Overall, integrated aquaculture systems exhibited a higher prevalence of resistance genes compared with monoculture freshwater aquaculture farms. Therefore, additional antimicrobial resistance surveillance should be focused on this type of freshwater aquaculture system. [ABSTRACT FROM AUTHOR]

Since its discovery in 2015, the mobile colistin resistance gene mcr-1 has been reported in bacteria from > 50 countries. Although aquaculture-associated bacteria may act as a significant reservoir for colistin resistance, systematic investigations of mcr-1 in the aquaculture supply chain are scarce. We investigated the presence of colistin resistance determinants in the aquaculture supply chain in south China and determined their characteristics and relationships. A total of 250 samples were collected from a duck-fish integrated fishery, slaughter house, and market in Guangdong Province, China, in July 2017. Colistin-resistant bacteria were isolated on colistin-supplemented CHROMagar Orientation plates, and the species were identified by matrix-assisted laser desorption/ionization time-of-flight assay. The presence of mcr genes was confirmed by polymerase chain reaction analysis. We examined the minimum inhibitory concentrations (MICs) of 16 antimicrobial agents against the isolates using agar diffusion and broth microdilution methods. Whole-genome sequencing (WGS) was used to explore the molecular characteristics and relationships of mcr-1 -positive Escherichia coli (MCRPEC). Overall, 143 (57.2%) colistin-resistant bacteria were isolated, of which, 56 (22.4%, including 54 Escherichia coli and two Klebsiella pneumoniae) and four Aeromonas species were positive for mcr-1 and mcr-3 , respectively. The animal-derived MCRPEC were significantly more prevalent in integrated fishery samples (40.0%) than those in market (4.8%, P < 0.01) samples but not in slaughter house (28.0%, P = 0.164). All MCRPEC were highly resistant to ampicillin, tetracycline, and compound sulfamethoxazole (>90%) but were susceptible to carbapenems and tigecycline. WGS analysis suggested that mcr-1 was mainly contained on plasmids, including IncHI2 (29.6%), IncI2 (27.8%), IncX4 (14.8%), and IncP (11.1%). Genomic analysis suggested mcr-1 transmission via the aquatic food chain. MCRPEC were highly prevalent in the aquaculture supply chain, with the isolates showing resistance to most antibiotics. The data suggested mcr-1 could be transferred to humans via the aquatic food chain. Taking the "One Health" perspective, aquaculture should be incorporated into systematic surveillance programs with animal, human, and environmental monitoring. • We reported a high prevalence (21.6%) of MCRPEC in aquaculture supply chain. • All MCRPEC isolates were resistant to most antimicrobial agents, in particular, those officially used in aquaculture. • We provide the evidence that mcr-1 could be transferred from animals to humans via the aquaculture supply chain. [ABSTRACT FROM AUTHOR]

While carbapenem use is prohibited in the poultry production chain and carbapenem-resistant Enterobacteriaceae (CRE) are absent from hatchery farms, New Delhi metallo-β-lactamase-producing CRE contamination of commercial broiler chicken farms (grow-out farms) can occur via living hosts such as flies. However, it is not known whether the inanimate factors from in-house environment play a role in the persistence of CRE on commercial farms. Herein, we monitored one typical broiler house in Hebei Province, China, from January 2017 to April 2018. We collected 350 cloacal samples from four broiler batches along with 582 environmental samples (194 in the raising period and 388 in the vacancy period) from sites including the surfaces of drooping boards, feeding troughs, nipple drinkers, corridor floors, sewage trenches, and air. All samples were screened for bla NDM and cultured for NDM-producing isolates. The resistance profiles, genotypes, and genetic context of bla NDM in CRE isolates were further characterized. Results showed that 1-day-old broilers, which were transferred from a hatchery farm and negative for CRE, acquired bla NDM within 24 h of transfer (2 days of age), with a detection rate of up to 18.6%. High bla NDM detection rates (26.8%-31.4%) were obtained among all environmental samples except air after standard cleaning and disinfection during the vacancy period. bla NDM carriage rates (52.9%-72.9%) within the flocks remain stable and high across the next three broiler batches. Overall, 279 NDM-producing bacteria, including 259 Enterobacteriaceae (8 species), 14 Morganellaceae (3 species), three Alcaligenes faecalis and three Pseudomonas putida isolates, were recovered from 85 (24.3%) cloacal and 101 (17.4%) environmental samples. Three NDM variants, including NDM-5 (n = 181), NDM-1 (n = 92), and NDM-9 (n = 3), and a novel NDM-like-metallo-β-lactamase (NLM, n = 3) were identified among the samples. The predominant NDM-producing CRE species among the samples were Klebsiella pneumoniae (CRKP; 32.6%, n = 91) and Escherichia coli (CREC; 27.2%, n = 76). Both clonal and horizontal transmission of bla NDM and an overlap of sequence types (STs) were observed in both CREC and CRKP from chicken and environmental samples. Notably, ST6751 CREC and ST37 CRKP persisted throughout the 16-month surveillance period. IncX3 (n = 197, 7 species), IncA/C 2 (n = 41, 5 species), and IncFII (n = 8, E. coli) were the three major bla NDM -carrying plasmid types among the isolates. Although routine cleaning and disinfection procedures and "all-in/all-out" management were performed, once introduced to the farm environment, a diverse range of NDM-positive isolates may survive and persist, becoming an important reservoir of NDM-positive CRE for broiler chickens. Therefore, cleaning and disinfection procedures should be improved on poultry farms to avoid cross-contamination of NDM-producing bacteria between different batches of chickens, as well as further downstream in the poultry production chain., 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 Ltd.. All rights reserved.)