Assessment of internal exposure risk from metals pollution of occupational and non-occupational populations around a non-ferrous metal smelting plant.

Non-ferrous metal smelting poses significant risks to public health. Specifically, the copper smelting process releases arsenic, a semi-volatile metalloid, which poses an emerging exposure risk to both workers and nearby residents. To comprehensively understand the internal exposure risks of metal(loid)s from copper smelting, we explored eighteen metal(loid)s and arsenic metabolites in the urine of both occupational and non-occupational populations using inductively coupled plasma mass spectrometry with high-performance liquid chromatography and compared their health risks. Results showed that zinc and copper (485.38 and 14.00 µg/L), and arsenic, lead, cadmium, vanadium, tin and antimony (46.80, 6.82, 2.17, 0.40, 0.44 and 0.23 µg/L, respectively) in workers (n=179) were significantly higher compared to controls (n=168), while Zinc, tin and antimony (412.10, 0.51 and 0.15 µg/L, respectively) of residents were significantly higher than controls. Additionally, workers had a higher monomethyl arsenic percentage (MMA%), showing lower arsenic methylation capacity. Source appointment analysis identified arsenic, lead, cadmium, antimony, tin and thallium as co-exposure metal(loid)s from copper smelting, positively relating to the age of workers. The hazard index (HI) of workers exceeded 1.0, while residents and control were approximately at 1.0. Besides, all three populations had accumulated cancer risks exceeding 1.0 × 10-4, and arsenite (AsIII) was the main contributor to the variation of workers and residents. Furthermore, residents living closer to the smelting plant had higher health risks. This study reveals arsenic exposure metabolites and multiple metals as emerging contaminants for copper smelting exposure populations, providing valuable insights for pollution control in non-ferrous metal smelting.

Carbonyl-amine condensation coupled ozonolysis of dipropylamine and styrene: Decay kinetics, reaction mechanism, secondary organic aerosol formation and cytotoxicity.

Oxidation of organic amines (OAs) or aromatic hydrocarbons (AHs) produces carbonyls, which further react with OAs to form carbonyl-amine condensation products, threatening environmental quality and human health. However, there is still a lack of systematic understanding of the carbonyl-amine condensation reaction processes of OAs or between OAs and AHs, and subsequent environmental health impact. This work systematically investigated the carbonyl-amine condensation coupled ozonolysis kinetics, reaction mechanism, secondary organic aerosol (SOA) formation and cytotoxicity from the mixture of dipropylamine (DPA) and styrene (STY) by a combined method of product mass spectrometry identification, particle property analysis and cell exposure evaluation. The results from ozonolysis of DPA and STY mixture revealed that STY inhibited the ozonolysis of DPA to different degrees to accelerate its own decay rate. The barycenter of carbonyl-amine condensation reactions was shifted from inside of DPA to between DPA and STY, which accelerated STY ozonolysis, but slowed down DPA ozonolysis. For the first time, ozonolysis of DPA and STY mixture to complex carbonyl-amine condensation products through the reactions of DPA with its carbonyl products, DPA with STY's carbonyl products and DPA's bond breakage product with STY's carbonyl products was confirmed. These condensation products significantly contributed to the formation and growth of SOA. The SOA containing particulate carbonyl-amine condensation products showed definite cytotoxicity. These findings are helpful to deeply and comprehensively understand the transformation, fate and environmental health effects of mixed organics in atmospheric environment.

Impact of coking plant to heavy metal characteristics in groundwater of surrounding areas: Spatial distribution, source apportionment and risk assessments.

Coking industry is a potential source of heavy metals (HMs) pollution. However, its impacts to the groundwater of surrounding residential areas have not been well understood. This study investigated the pollution characteristics and health risks of HMs in groundwater nearby a typical coking plant. Nine HMs including Fe, Zn, Mo, As, Cu, Ni, Cr, Pb and Cd were analyzed. The average concentration of total HMs was higher in the nearby area (244.27 µg/L) than that of remote area away the coking plant (89.15 µg/L). The spatial distribution of pollution indices including heavy metal pollution index (HPI), Nemerow index (NI) and contamination degree (CD), all demonstrated higher values at the nearby residential areas, suggesting coking activity could significantly impact the HMs distribution characteristics. Four sources of HMs were identified by Positive Matrix Factorization (PMF) model, which indicated coal washing and coking emission were the dominant sources, accounted for 40.4%, and 31.0%, respectively. Oral ingestion was found to be the dominant exposure pathway with higher exposure dose to children than adults. Hazard quotient (HQ) values were below 1.0, suggesting negligible non-carcinogenic health risks, while potential carcinogenic risks were from Pb and Ni with cancer risk (CR) values > 10-6. Monte Carlo simulation matched well with the calculated results with HMs concentrations to be the most sensitive parameters. This study provides insights into understanding how the industrial coking activities can impact the HMs pollution characteristics in groundwater, thus facilitating the implement of HMs regulation in coking industries.

Selective enrichment of high-risk antibiotic resistance genes and priority pathogens in freshwater plastisphere: Unique role of biodegradable microplastics.

Microplastics (MPs) has been concerned as emerging vectors for spreading antibiotic resistance and pathogenicity in aquatic environments, but the role of biodegradable MPs remains largely unknown. Herein, field in-situ incubation method combined with metagenomic sequencing were employed to reveal the dispersal characteristics of microbial community, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and virulence factors (VFs) enriched by MPs biofilms. Results showed that planktonic microbes were more prone to enrich on biodegradable MPs (i.e., polyhydroxyalkanoate and polylactic acid) than non-biodegradable MPs (i.e., polystyrene, polypropylene and polyethylene). Distinctive microbial communities were assembled on biodegradable MPs, and the abundances of ARGs, MGEs, and VFs on biofilms of biodegradable MPs were much higher than that of non-biodegradable MPs. Notably, network analysis showed that the biodegradable MPs selectively enriched pathogens carrying ARGs, VFs and MGEs concurrently, suggesting a strong potential risks of co-spreading antibiotic resistance and pathogenicity through horizontal gene transfer. According to WHO priority list of Antibiotic Resistant Pathogens (ARPs) and ARGs health risk assessment framework, the highest abundances of Priority 1 ARPs and Rank I risk ARGs were found on polylactic acid and polyhydroxyalkanoate, respectively. These findings elucidate the unique and critical role of biodegradable MPs for selective enrichment of high-risk ARGs and priority pathogens in freshwater environments.

Photocatalysis Inhibits the Emergence of Multidrug-Resistant Bacteria in an Antibiotic-Resistant Bacterial Community in Aquatic Environments.

Bacterial antibiotic resistance has recently attracted increasing amounts of attention. Here, an artificially antibiotic-resistant bacterial community (ARBC) combined with five different constructed antibiotic-resistant bacteria (ARB) with single antibiotic resistance, namely, kanamycin (KAN), tetracycline (TET), cefotaxime (CTX), polymyxin B (PB), or gentamicin (GEM), was studied for the stress response to photocatalysis. With photocatalytic inactivation, the transfer and diffusion of antibiotic resistance genes (ARGs) in the ARBC decreased, and fewer multidrug-resistant bacteria (MDRB) emerged in aquatic environments. After several days of photocatalytic inactivation or Luria broth cultivation, >90% ARB were transformed to antibiotic-susceptible bacteria by discarding ARGs. Bacteria with double antibiotic resistance were the dominant species (99%) of residual ARB. The changes in ARG abundance varied, decreasing for the GEM and TET resistance genes and increasing for the KAN resistance genes. The change in the antibiotic resistance level was consistent with the change in ARG abundance. Correspondingly, point mutations occurred for the KAN, CTX and PB resistance genes after photocatalytic inactivation, which might be the reason why these genes persisted longer in the studied ARBC. In summary, photocatalytic inactivation could reduce the abundance of some ARGs and inhibit the emergence of MDRB as well as block ARG transfer in the bacterial community in aquatic environments. This work highlights the advantages of long-term photocatalytic inactivation for controlling antibiotic resistance and facilitates a better understanding of bacterial communities in real aquatic environments.

Continuous measurement of the dynamics of residential indoor and outdoor NO2 and the contributions to human exposure.

In residential environment, NO2 is an important air pollutant. Yet, the dynamics of indoor NO2 and source contributions to human exposure are not well understood. Here, we conducted a continuous NO2 measurement in and out of eight households in Guangzhou, China. Paired high time-resolution NO2 data sets indoors (kitchen, living room) and outdoors (balcony) were obtained with NO2 monitors. We summarized the indoor and outdoor NO2 levels, identified temporal variation patterns, analyzed indoor-outdoor relationships, and quantified source contributions to indoor NO2 exposure. Indoor NO2 were overall higher than outdoor NO2, and in most cases, the highest NO2 levels were observed in the kitchen. NO2 in the kitchen was characterized by multiple spikes associated with use of gas stoves, while NO2 in the living room was also elevated but the peaks were generally smaller. The indoor-outdoor correlations were stronger in winter than in summer, and were stronger in nighttime than daytime. The sources contributing to indoor NO2 were separated with a conceptual model. Overall, the outdoor NO2 source contributed 73%-76% of the NO2 in the kitchen, and 76%-85% in the living room. The source pattern was quite different: outdoor NO2 sources were present indoors all the time; by contrast, indoor NO2 sources were present sporadically but with a very high contribution. This has important implication to the exposure assessment that indoor NO2 sources lead to short-term high exposure, and deserves attention regarding acute health effects.

Toxicity evolution of triclosan during environmental transformation and human metabolism: Misgivings in the post-pandemic era.

In the context of pandemic viruses and pathogenic bacteria, triclosan (TCS), as a typical antibacterial agent, is widely used around the world. However, the health risks from TCS increase with exposure, and it is widespread in environmental and human samples. Notably, environmental transformation and human metabolism could induce potentially undesirable risks to humans, rather than simple decontamination or detoxification. This review summarizes the environmental and human exposure to TCS covering from 2004 to 2023. Particularly, health impacts from the environmental and metabolic transformation of TCS are emphasized. Environmental transformations aimed at decontamination are recognized to form carcinogenic products such as dioxins, and ultraviolet light and excessive active chlorine can promote the formation of these dioxin congeners, potentially threatening environmental and human health. Although TCS can be rapidly metabolized for detoxification, these processes can induce the formation of lipophilic ether metabolic analogs via cytochrome P450 catalysis, causing possible adverse cross-talk reactions in human metabolic disorders. Accordingly, TCS may be more harmful in environmental transformation and human metabolism. In particular, TCS can stimulate the transmission of antibiotic resistance even at trace levels, threatening public health. Considering these accruing epidemiological and toxicological studies indicating the multiple adverse health outcomes of TCS, we call on environmental toxicologists to pay more attention to the toxicity evolution of TCS during environmental transformation and human metabolism.

Aqueous VOCs in complex water environment of oil exploitation sites: Spatial distribution, migration flux, and risk assessment.

Pollution of the aqueous environment by volatile organic compounds (VOCs) has caused increasing concerns. However, the occurrence and risks of aqueous VOCs in oil exploitation areas remain unclear. Herein, spatial distribution, migration flux, and environmental risks of VOCs in complex surface waters (including River, Estuary, Offshore and Aquaculture areas) were investigated at a typical coastal oil exploitation site. Among these surface waters, River was the most polluted area, and 1,2-Dichloropropane-which emerges from oil extraction activities-was the most prevalent VOC. Positive matrix factorization showed that VOCs pollution sources changed from oil exploitation to offshore disinfection activities along River, Estuary, Offshore and Aquaculture areas. Annual volatilization of VOCs to the atmosphere was predicted to be ∼34.42 tons, and rivers discharge ∼23.70 tons VOCs into the Bohai Sea annually. Ecological risk assessment indicated that Ethylbenzene and Bromochloromethane posed potential ecological risks to the aquatic environment, while olfactory assessment indicated that VOCs in surface waters did not pose an odor exposure risk. This study provides the first assessment of the pollution characteristics of aqueous VOCs in complex aqueous environments of oil exploitation sites, highlighting that oil exploitation activities can have nonnegligible impacts on VOCs pollution profiles.

Indoor/Outdoor airborne microbiome characteristics in residential areas across four seasons and its indoor purification.

Bioaerosols are more likely to accumulate in the residential environment, and long-term inhalation may lead to a variety of diseases and allergies. Here, we studied the distribution, influencing factors and diffusion characteristics of indoor and outdoor microbiota pollution in six residential buildings in Guangzhou, southern China over a period of one year. The results showed that the particle sizes of bioaerosol were mainly in the range of inhalable particle size (<4.7 µm) with a small difference among four seasons (74.61 % ± 2.17 %). The microbial communities showed obvious seasonal differences with high abundance in summer, but no obvious geographical differences. Among them, the bacteria were more abundant than the fungi. The dominant microbes in indoor and outdoor environments were similar, with Anoxybacillu, Brevibacillus and Acinetobacter as the dominant bacteria, and Cladosporium, Penicillium and Alternaria as the dominant fungi. The airborne microbiomes were more sensitive to temperature and particulate matter (PM2.5, PM10) concentrations. Based on the Sloan neutral model, bacteria were more prone to random diffusion than fungi, and the airborne microbiome can be randomly distributed in indoor and outdoor environments and between the two environments in each season. Bioaerosol in indoor was mainly from outdoor. The health risk evaluation showed that the indoor inhalation risks were higher than those outdoor. The air purifier had a better removal efficiency on 1.1-4.7 µm microorganisms, and the removal efficiency on Gram-negative bacteria was better than that on Gram-positive bacteria. This study is of great significance for the risk assessment and control of residential indoor bioaerosol exposure.

Can photocatalysis inhibit interspecies bacterial cooperation to quench the formation of robust complex bacterial biofilms in water environments?

Bacterial biofilms pose significant a public health risk as an environmental reservoir for opportunistic aquatic bacterial pathogens. Understanding the interspecies roles of complex bacterial biofilms under different stimuli and regulatory mechanisms of stress responses is the key to controlling their dissemination. Herein, two-species mixture (TSM) biofilms (Staphylococcus aureus and Pseudomonas aeruginosa) were constructed in a flowthrough reactor. Compared with the single-species biofilms, the TSM biofilm had higher growth activity to reach maturity faster, forming a staggered community structure. Moreover, the TSM biofilm exhibited greatly improved resistance to different antibiotics (16-128 times higher), especially to those that act on protein synthesis and cell membrane integrity, when compared to single planktonic microorganisms. In the presence of stimuli, photocatalysis effectively inactivated the TSM biofilm within 10 h, a 4-fold shorter inactivation time compared to UVC irradiation. In addition, photocatalysis effectively depleted the extracellular polymers of the TSM biofilm and inhibited secretion of their interspecies quorum sensing signaling molecule autoinducer-2 (AI-2). However, the expression of AI-2 induced related virulence factors, and biofilm growth-related genes were initially up-regulated 3 - 10 fold for the TSM biofilm within the first 2 - 4 h of photocatalysis, followed by significant down-regulation. Furthermore, the addition of the AI-2 precursor 4,5-dihydroxy-2,3-pentanedione effectively delayed the photocatalytic inactivation efficiency of the TSM biofilm compared to the control. These results suggest that photocatalysis can effectively inactivate biofilms by inhibiting interspecies cooperation by quenching AI-2 in the TSM biofilm. This work sheds light on controlling biofilms in public health engineering systems.

A review of disrupted biological response associated with volatile organic compound exposure: Insight into identification of biomarkers.

Volatile organic compounds (VOCs) are widespread harmful atmospheric pollutants, which have long been concerned and elucidated to be one of the risks of acute and chronic diseases for human, such as leukemia and cancer. Although numerous scientific studies have documented the potential adverse outcomes caused by VOC exposure, the mechanisms which biological response pathways of these VOC disruption remain poorly understood. Therefore, the identification of biochemical markers associated with metabolism, health effects and diseases orientation can be an effective means of screening biological targets for VOC exposure, which provide evidences to the toxicity assessment of compounds. The current review aims to understand the mechanisms underlying VOCs-elicited adverse outcomes by charactering various types of biomarkers. VOCs-related biomarkers from three aspects were summarized through in vitro, animal and epidemiological studies. i) Unmetabolized and metabolized VOC biomarkers in human samples for assessing exposure characteristics in different communities; ii) Adverse endpoint effects related biomarkers, mainly including (anti)oxidative stress, inflammation response and DNA damage; iii) Omics-based molecular biomarkers alteration in gene, protein, lipid and metabolite aspects associated with biological signaling pathway disorders response to VOC exposure. Further research, advanced machine learning and bioinformation approaches combined with experimental results are urgently needed to ascertain the selection of biomarkers and further illuminate toxic mechanisms of VOC exposure. Finally, VOCs-induced disease causes can be predicted with proven results.

Polybrominated diphenyl ethers and their alternatives in soil cores from a typical flame-retardant production park: Vertical distribution and potential influencing factors.

With the prohibition on the production and use of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and organophosphate flame retardants (OPFRs) have emerged as their alternatives. However, the vertical transport and associated influencing factors of these chemicals into soil are not clearly understood. To clarify the vertical distribution of the pollutants and related influencing factors, surface soil and soil core samples were collected at a depth in the range of 0.10-5.00 m in a typical 20-year-old flame-retardant production park and surrounding area. PBDEs and DBDPE show a clear point source distribution around the production park with their central concentrations up to 2.88 × 104 and 8.46 × 104 ng/g, respectively. OPFRs are mainly found in residential areas. The production conversion of PBDEs to DBDPE has obvious environmental characteristics. The vertical distribution revealed that most of the pollutants have penetrated into the soil 5.00 m or even deeper. The median concentrations of deca-BDE and DBDPE reached 50.9 and 9.85 × 103 ng/g, respectively, even at a depth of 5.00 m. Soil organic matter plays a crucial role in determining the vertical distribution, while soil clay particles have a greater impact on the high molecular weight and/or highly brominated compounds.

Recent progress in online detection methods of bioaerosols.

The aerosol transmission of coronavirus disease in 2019, along with the spread of other respiratory diseases, caused significant loss of life and property; it impressed upon us the importance of real-time bioaerosol detection. The complexity, diversity, and large spatiotemporal variability of bioaerosols and their external/internal mixing with abiotic components pose challenges for effective online bioaerosol monitoring. Traditional methods focus on directly capturing bioaerosols before subsequent time-consuming laboratory analysis such as culture-based methods, preventing the high-resolution time-based characteristics necessary for an online approach. Through a comprehensive literature assessment, this review highlights and discusses the most commonly used real-time bioaerosol monitoring techniques and the associated commercially available monitors. Methods applied in online bioaerosol monitoring, including adenosine triphosphate bioluminescence, laser/light-induced fluorescence spectroscopy, Raman spectroscopy, and bioaerosol mass spectrometry are summarized. The working principles, characteristics, sensitivities, and efficiencies of these real-time detection methods are compared to understand their responses to known particle types and to contrast their differences. Approaches developed to analyze the substantial data sets obtained by these instruments and to overcome the limitations of current real-time bioaerosol monitoring technologies are also introduced. Finally, an outlook is proposed for future instrumentation indicating a need for highly revolutionized bioaerosol detection technologies.

An overview for monitoring and prediction of pathogenic microorganisms in the atmosphere.

Corona virus disease 2019 (COVID-19) has exerted a profound adverse impact on human health. Studies have demonstrated that aerosol transmission is one of the major transmission routes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pathogenic microorganisms such as SARS-CoV-2 can survive in the air and cause widespread infection among people. Early monitoring of pathogenic microorganism transmission in the atmosphere and accurate epidemic prediction are the frontier guarantee for preventing large-scale epidemic outbreaks. Monitoring of pathogenic microorganisms in the air, especially in densely populated areas, may raise the possibility to detect viruses before people are widely infected and contain the epidemic at an earlier stage. The multi-scale coupled accurate epidemic prediction system can provide support for governments to analyze the epidemic situation, allocate health resources, and formulate epidemic response policies. This review first elaborates on the effects of the atmospheric environment on pathogenic microorganism transmission, which lays a theoretical foundation for the monitoring and prediction of epidemic development. Secondly, the monitoring technique development and the necessity of monitoring pathogenic microorganisms in the atmosphere are summarized and emphasized. Subsequently, this review introduces the major epidemic prediction methods and highlights the significance to realize a multi-scale coupled epidemic prediction system by strengthening the multidisciplinary cooperation of epidemiology, atmospheric sciences, environmental sciences, sociology, demography, etc. By summarizing the achievements and challenges in monitoring and prediction of pathogenic microorganism transmission in the atmosphere, this review proposes suggestions for epidemic response, namely, the establishment of an integrated monitoring and prediction platform for pathogenic microorganism transmission in the atmosphere.

Emerging contaminants: A One Health perspective.

Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health. Despite global efforts to mitigate legacy pollutants, the continuous introduction of new substances remains a major threat to both people and the planet. In response, global initiatives are focusing on risk assessment and regulation of emerging contaminants, as demonstrated by the ongoing efforts to establish the UN's Intergovernmental Science-Policy Panel on Chemicals, Waste, and Pollution Prevention. This review identifies the sources and impacts of emerging contaminants on planetary health, emphasizing the importance of adopting a One Health approach. Strategies for monitoring and addressing these pollutants are discussed, underscoring the need for robust and socially equitable environmental policies at both regional and international levels. Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.

Mechanism of cytochrome P450s mediated interference with glutathione and amino acid metabolisms from halogenated PAHs exposure.

Epidemiological evidence indicates that exposure to halogenated polycyclic aromatic hydrocarbons (HPAHs) is associated with many adverse effects. However, the mechanisms of metabolic disorder of HPAHs remains limited. Herein, effects of pyrene (Pyr), and its halogenated derivatives (1-chloropyrene (1-Cl-Pyr), 1-bromopyrene (1-Br-Pyr)) on endogenous metabolic pathways were investigated, in human hepatoma (HepG2) and HepG2-derived cell lines expressing various human cytochrome P450s (CYPs). Non-targeted metabolomics results suggested that 1-Br-Pyr and Pyr exposure (625 nM) induced disruption in glutathione and riboflavin metabolism which associated with redox imbalance, through abnormal accumulation of oxidized glutathione, mediated by bioactivation of CYP2E1. Conversely, CYP2C9-mediated 1-Cl-Pyr significantly interfered with glutathione metabolism intermediates, including glycine, L-glutamic acid and pyroglutamic acid. Notably, CYP1A1-mediated Pyr-induced perturbation of amino acid metabolism which associated with nutrition and glycolipid metabolism, resulting in significant upregulation of most amino acids, whereas halogenated derivatives mediated by CYP1A2 substantially downregulated amino acids. In conclusion, this study suggested that Pyr and its halogenated derivatives exert potent effects on endogenous metabolism disruption under the action of various exogenous metabolic enzymes (CYPs). Thus, new evidence was provided to toxicological mechanisms of HPAHs, and reveals potential health risks of HPAHs in inducing diseases caused by redox and amino acid imbalances.

Associations of multiple hydroxy-polycyclic aromatic hydrocarbons with serum levels of lipids in the workers from coking and non-ferrous smelting industries.

Epidemiological evidence indicates that exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with certain metabolic diseases. However, the relationship between PAHs and serum lipid profiles in exposed subjects remain unknown. Herein, the associations of multiple (8) urinary hydroxylated PAHs (OH-PAHs) in workers of coking (n = 655) and non-ferrous smelting (n = 614) industries with serum lipid levels (marking lipid metabolism) were examined. Multivariable linear regression, Bayesian kernel machine regression, and quantile g-computation were used. Most urinary OH-PAHs were significantly higher (p < 0.001) in coking workers than in non-ferrous smelting workers. In workers of both industries, OH-PAH exposure was associated with elevated levels of serum total cholesterol, total triglyceride, and low-density lipoprotein, as well as reduced high-density lipoprotein levels. Specifically, urinary 4-hydroxyphenanthrene was significantly positively associated with serum total cholesterol, total triglyceride, and low-density lipoprotein levels in non-ferrous smelting workers; however, the completely opposite association of 4-hydroxyphenanthrene with these lipid levels was observed in coking workers. The results of this pioneering examination suggest that exposure to OH-PAHs may contribute to dyslipidemia in coking and non-ferrous smelting workers, and distinct patterns of change were observed. Further prospective studies involving larger sample sizes are needed to further validate the findings.

The abundance and pathogenicity of microbes in automobile air conditioning filters across the typical cities of China and Europe.

Bioaerosols are widely distributed in urban air and can be transmitted across the atmosphere, biosphere, and anthroposphere, resulting in infectious diseases. Automobile air conditioning (AAC) filters can trap airborne microbes. In this study, AAC filters were used to investigate the abundance and pathogenicity of airborne microorganisms in typical Chinese and European cities. Culturable bacteria and fungi concentrations were determined using microbial culturing. High-throughput sequencing was employed to analyze microbial community structures. The levels of culturable bioaerosols in Chinese and European cities exhibited disparities (Analysis of Variance, P < 0.01). The most dominant pathogenic bacteria and fungi were similar in Chinese (Mycobacterium: 18.2-18.9 %; Cladosporium: 23.0-30.2 %) and European cities (Mycobacterium: 15.4-37.7 %; Cladosporium: 18.1-29.3 %). Bartonella, Bordetella, Alternaria, and Aspergillus were also widely identified. BugBase analysis showed that microbiomes in China exhibited higher abundances of mobile genetic elements (MGEs) and biofilm formation capacity than those in Europe, indicating higher health risks. Through co-occurrence network analysis, heavy metals such as zinc were found to correlate with microorganism abundance; most bacteria were inversely associated, while fungi exhibited greater tolerance, indicating that heavy metals affect the growth and reproduction of bioaerosol microorganisms. This study elucidates the influence of social and environmental factors on shaping microbial community structures, offering practical insights for preventing and controlling regional bioaerosol pollution.

Mechanism of antibiotic resistance spread during sub-lethal ozonation of antibiotic-resistant bacteria with different resistance targets.

The increase and spread of antibiotic-resistant bacteria (ARB) in aquatic environments and the dissemination of antibiotic resistance genes (ARGs) greatly impact environmental and human health. It is necessary to understand the mechanism of action of ARB and ARGs to formulate measures to solve this problem. This study aimed to determine the mechanism of antibiotic resistance spread during sub-lethal ozonation of ARB with different antibiotic resistance targets, including proteins, cell walls, and cell membranes. ARB conjugation and transformation frequencies increased after exposure to 0-1.0 mg/L ozone for 10 min. During sub-lethal ozonation, compared with control groups not stimulated by ozone, the conjugative transfer frequencies of E. coli DH5α (CTX), E. coli DH5α (MCR), and E. coli DH5α (GEN) increased by 1.35-2.02, 1.13-1.58, and 1.32-2.12 times, respectively; the transformation frequencies of E. coli DH5α (MCR) and E. coli DH5α (GEN) increased by 1.49-3.02 and 1.45-1.92 times, respectively. When target inhibitors were added, the conjugative transfer frequencies of antibiotics targeting cell wall and membrane synthesis decreased 0.59-0.75 and 0.43-0.76 times, respectively, while that for those targeting protein synthesis increased by 1-1.38 times. After inhibitor addition, the transformation frequencies of bacteria resistant to antibiotics targeting the cell membrane and proteins decreased by 0.76-0.89 and 0.69-0.78 times, respectively. Cell morphology, cell membrane permeability, reactive oxygen species, and antioxidant enzymes changed with different ozone concentrations. Expression of most genes related to regulating different antibiotic resistance targets was up-regulated when bacteria were exposed to sub-lethal ozonation, further confirming the target genes playing a crucial role in the inactivation of different target bacteria. These results will help guide the careful utilization of ozonation for bacterial inactivation, providing more detailed reference information for ozonation oxidation treatment of ARB and ARGs in aquatic environments.

Online monitoring system for qualitative and quantitative analysis of bioaerosols by combined ATP bioluminescence assay with loop-mediated isothermal amplification.

Rapid detection of airborne pathogens is crucial in preventing respiratory infections and allergies. However, technologies aiming to real-time analysis of microorganisms in air remain limited due to the sparse and complex nature of bioaerosols. Here, we introduced an online bioaerosol monitoring system (OBMS) comprised of integrated units including a rotatable stainless-steel sintered filter-based sampler, a lysis unit for extracting adenosine triphosphate (ATP), and a single photon detector-based fluorescence unit. Through optimization of the ATP bioluminescence method and establishment of standard curves between relative luminescence units (RLUs) and ATP as well as microbial concentration, we achieved simultaneous detection of bioaerosols' concentration and activity. Testing OBMS with four bacterial and two fungal aerosols at a sampling flow rate of 10 to 50 L/min revealed an outstanding collection efficiency of 95 % at 30 L/min. A single OBMS measurement takes only 8 min (sampling: 5 min; lysis and detection: 3 min) with detection limits of 3 Pcs/ms photons (2.9 × 103 and 292 CFU/m3 for Staphylococcus aureus and Candida albicans aerosol). In both laboratory and field tests, OBMS detected higher concentrations of bioaerosol compared to the traditional Andersen impactor and liquid biosampler. When combined OBMS with loop-mediated isothermal amplification (LAMP), the bioaerosol can be qualitative and quantitative analyzed within 40 min without the cumbersome procedures of sample pretreatment and DNA extraction. These results offer a high compressive and humidity resistance membrane filtration sampler and validate the potential of OBMS for online measurement of bioaerosol concentration and composition.