The atmosphere serves as a reservoir and transmission pathway for pathogenic microorganisms and antimicrobial resistance genes (ARGs), which can be inhaled or ingested and pose emerging public health risks. Despite growing awareness of antimicrobial resistance in soil and water, the air resistome—the characterization of ARGs in airborne matrices remains relatively understudied. Humans can inhale thousands of resistance genes daily as airborne ARGs occur at 103–105 gene copies/m³ of air. Human population growth and intensive anthropogenic activities have profoundly altered natural ecosystems, reshaping microbial community structures in the atmosphere. Urban and rural environments differ in emission sources, land use, and pollution profiles, necessitating distinct approaches to assess and mitigate their respective air resistome. However, most existing studies emphasize bacterial diversity rather than the occurrence, abundance, and dissemination of ARGs across these environments. Understanding the spatial variability of airborne ARGs is critical for developing early warning systems and informing public health surveillance. This review emphasizes current knowledge on ARG gradients from urban to rural settings, highlights the role of anthropogenic drivers in their distribution, and identifies key knowledge gaps. We advocate for the routine monitoring of biological pollutants, including ARGs, as part of comprehensive air quality management and regulatory frameworks. Finally, integrating One Health approach into policy ensures holistic AMR control across humans, animals, and ecosystem.

Ammonia (NH3), nitrogen oxides (NO x ), and nitrous acid (HONO) are key components of atmospheric reactive nitrogen (Nr), playing pivotal and interconnected roles in the formation of secondary pollutants such as PM2.5 and ozone. However, their diverse emission sources and complex atmospheric transformations introduce substantial uncertainties when quantifying sector-specific Nr contributions with conventional bottom-up emission inventories. Stable nitrogen isotopes (δ15N), which preserve source-dependent isotopic fingerprints, provide a powerful complementary approach for constraining the sources and tracing the processes of atmospheric Nr. This review synthesizes recent advances in δ15N-based research on atmospheric Nr, including measurement techniques, source signatures, source apportionment applications, and methodological developments. We compile δ15N signature ranges for major NH3, NO x , and HONO emission sources, summarize current approaches for estimating isotopic fractionation associated with these species, and critically evaluate the applicability and limitations of commonly used isotope mixing models. Existing evidence shows that large inter-source contrasts in δ15N signatures, when combined with well-constrained fractionation estimates and appropriately selected mixing models, allow isotopic source apportionment to achieve high discriminatory power. We further aggregate δ15N-based source apportionment studies conducted in China over the past decade. Accumulating studies consistently highlight significant contributions from nonagricultural NH3, non-fossil NO x , and direct HONO emissions, which have often been underestimated. This underscores the need to prioritize these nontraditional sources in Nr characterization and control strategies. Overall, enhancing the identification of nontraditional Nr sources via δ15N analysis is critical for developing scientifically robust Nr budgets and formulating effective pollution control policies.

The integration of circular economy (CE) principles into hospital operations, focusing on environmental, economic, and operational outcomes, represents a pressing challenge within the current healthcare system. This study systematically reviewed 11 peer-reviewed studies selected from 5976 articles published between 2014 and 2025 following the PRISMA 2020 guidelines, including life cycle assessment (LCA) and material flow analysis (MFA) investigations. Evidence consistently indicates that reusable and repairable medical devices significantly outperform single-use alternatives, achieving up to a 76% reduction in carbon emissions and 50% cost savings. MFA studies revealed that single-use plastics, particularly gloves, gowns, and packaging, constitute more than 70% of hospital waste, highlighting critical targets for CE intervention. Furthermore, integrated waste management systems that combine segregation and recycling demonstrate superior environmental performance compared to incineration-dominated approaches. Despite these clear benefits, barriers such as regulatory inertia, limited sterilization infrastructure, and procurement models favoring disposables impede the adoption of CEs. Conversely, enabling factors include green procurement policies, digital tracking tools, and leadership-driven sustainability programs. Major research gaps remain regarding CE implementation in low- and middle-income countries, standardized LCA methodologies, and behavioral factors that influence adoption. The findings underscore the transformative potential of CE strategies such as reuse, repair, remanufacturing, and resource recovery in decarbonizing healthcare while maintaining safety and efficiency. This analysis evaluates Scope 1 (direct), 2 (indirect), and 3 (supply-chain) emissions reduction strategies. Integrating CE metrics into procurement and policy frameworks could make healthcare a sustainability leader.

Biodegradable polyesters (BPEs) are increasingly being promoted as sustainable alternatives to conventional plastics, particularly in applications where biodegradability offers an advantage because material retrieval is impractical or impossible. Agriculture is a typical example of such applications. However, the growing interest in BPEs has also raised legitimate concerns regarding potential environmental side effects, especially the formation and fate of biodegradable microparticles (“microbioplastics”) in soils. This review critically examines the current understanding of the degradation mechanisms, ecological interactions, and environmental implications of BPEs under soil conditions. Evidence suggests that, at environmentally and agriculturally realistic loading rates, most effects on soil properties are transient and comparable to those induced by natural biodegradable organic inputs such as lignocellulose. Fragmentation of and biofilm formation on BPEs, often interpreted as adverse effects, are in fact inherent stages of microbial degradation and carbon cycling. Overall, assessing the impact of BPEs on soil ecosystems remains a highly relevant and rapidly evolving research area, requiring adherence to sound scientific principles, realistic exposure scenarios, and standardized methodologies. Integrating microplastic characterization and temporal analyses into future certification and testing frameworks will strengthen the scientific foundation for evaluating the environmental safety of these materials and support their responsible implementation in sustainable agriculture and soil management.

Anaerobic ammonium oxidation (anammox), as a breakthrough low-carbon nitrogen removal technology, is energy-efficient and cost-effective for treating high-ammonium, low C/N wastewaters. However, excessive concentrations of ammonium (NH4 +) and nitrite (NO2 −), especially in the form of free ammonia (FA) and free nitrous acid (FNA), exert strong biotoxic effects on anammox bacteria (AnAOB) and severely hinder the wide application of the anammox process. In this review, we comprehensively evaluate high-nitrogen inhibition in anammox systems, focusing on impacts on nitrogen removal performance and sludge properties. From molecular–cellular–ecological perspectives, this work systematically elucidates the inhibition and response mechanisms under high-nitrogen stress, covering membrane structure, key enzymes and functional genes, extracellular polymeric substances (EPS), and microbial community. In addition, we explore the roles of coexisting organics and microbial interactions in system-level responses. To mitigate high-nitrogen inhibition, a series of effective recovery strategies are summarized, including biomass intervention management, process parameter optimization, and exogenous additive supplementation. Finally, we propose biological enhancement measures based on the enrichment of Ca. Kuenenia to improve anammox tolerance. This review bridges microbial insights and engineering applications to advance the broader implementation of anammox-based systems in full-scale wastewater treatment.

In aquatic ecosystems, agricultural activities have an impact on eutrophication and contribute to the excessive growth of cyanobacteria. Although harmful cyanobacterial blooms (HCBs) are known to increase with nutrient enrichment and climate change, it is unclear how herbicide influences cyanobacterial dominance and related cyanotoxins production. This critical review presents emerging, cumulative evidence revealing how herbicide exposure can change phytoplankton communities by reducing sensitive taxa and indirectly promoting toxin-producing cyanobacteria. It also explores how such stressors can trigger the production and release of cyanotoxins, which may have, in turn, a synergistic toxic effect with herbicides on sensitive phytoplankton, although their combined effects on aquatic biota are still poorly understood. Methodological challenges including laboratory research, mesocosms and fieldwork are discussed to assess the ecological significance. These recommendations are supported by state-of-the-art methods in analytical chemistry, molecular biology, and multivariate statistics for better integrated risk assessments of complex interactions between herbicides, cyanobacteria and cyanotoxins on aquatic ecosystems.

Despite the wide deployment of polyamide nanofiltration (NF) and reverse osmosis (RO) membranes in water treatment, their poor resistance to oxidants (e.g., hypochlorite) often results in compromised separation performance. In this review, we extracted physicochemical properties and separation performance of polyamide NF/RO membranes before and after oxidation from the literature for systematic data analysis. The results showed that the fully-aromatic membranes are more prone to oxidation compared to the semi-aromatic membranes. Severe oxidation could significantly damage polyamide network, leading to deteriorated polyamide nanofeatures, varied hydrophilicity depending on pH (e.g., more hydrophilic after alkaline oxidation), increased negative charge, and enhanced O/N ratio. Moreover, the fully-aromatic polyamide membranes often demonstrate enhanced water permeance after neutral and alkaline oxidation due to the degradation of polyamide. Meanwhile, the membranes showed deceased rejection and selectivity of salts after severe oxidation. In addition, an initial evaluation of micropollutant rejection was performed based on the currently limited available literature data, but a comprehensive and systematic investigation into the oxidation impact on water-micropollutant selectivity is still lacking and represents a critical area for future research. We further analyzed the chlorination-properties-performance relationship to highlight the importance of oxidation-induced O/N ratio change on membrane separation performance. In addition, the Janus impacts of oxidation (e.g., damaging membranes with compromised performance and polishing membranes for enhanced performance) were highlighted. Moreover, we outlooked the development of novel anti-oxidation membranes and oxidation polished membranes for specific applications in water treatment.

Chemical bioaccumulation, which links internal exposure to hazards, plays a crucial role in ecological and human health risk assessment. Traditional bioaccumulation evaluations rely on laboratory-simulated exposure experiments and field monitoring studies, facing limitations in high cost, time constraints, and ethical concerns. Mechanistic toxicokinetic (TK) models and data-driven quantitative structure-activity relationship (QSAR) approaches have emerged as efficient alternatives. The review synthesizes decades of progress in TK and QSAR models for bioaccumulation prediction of chemicals in aquatic organisms, encompassing theoretical foundations, mathematical equations, practical applications, and current research gaps. While traditional compartmental TK models provide simplicity, physiologically-based toxicokinetic (PBTK) models enhance accuracy by incorporating species-specific physiology and chemical-dependent biochemical parameters. Existing PBTK models are currently limited to 10 fish species and 133 chemicals across 29 categories, with applications focused on internal concentration dynamics predictions, cross-species extrapolation, in vitro to in vivo extrapolation, and toxicity integration. Major limitations include a taxonomic bias toward fish, inadequate contaminant coverage, oversimplified environmental parameterization, incomplete mechanistic representations, and parameter scarcity. QSAR models have evolved from linear regression to machine learning approaches, achieving superior prediction performance through enhancing molecular representations and incorporating advanced algorithms. Nonetheless, challenges remain in TK parameter prediction and high-quality data acquisition. The review offers valuable insights and methodological advancements to support chemical risk assessment.

Accurate prediction of methane (CH4) emissions from agricultural lands, particularly rice paddies, is essential for effective climate change mitigation. Although current models capture broad emission trends, they often struggle to represent the complex interactions among the processes that govern CH4 production, oxidation, transport, and release. These challenges arise from multiple interconnected factors, including dynamic microbial communities with diverse metabolic pathways; fluctuating substrate availability shaped by rice management practices; and several transport mechanisms, such as diffusion, ebullition, and plant-mediated pathways, that are difficult to parameterize and scale. This review examines four interconnected dimensions of CH4 modeling: (a) how major CH4-related processes are conceptualized in existing models; (b) the quantitative performance of widely used CH4 models in rice systems; (c) the key limitations and challenges that constrain process-based CH4 simulations; and (d) opportunities for model improvement. Across these dimensions, the review provides an in-depth synthesis of the key biogeochemical and rice crop processes, including redox dynamics, substrate supply, microbial activity, CH4 production and oxidation, transport mechanisms, and rice plant–root–soil interactions. We argue that discrepancies between modeled and observed CH4 emissions arise not only from model assumptions and structural limitations but also from the inherent complexity of the system and limited data available for model development and evaluation. To enhance predictive accuracy, we highlight the need for improved representation of microbial processes, soil biogeochemistry, plant–soil interactions, and scaling approaches. Overall, this review provides an integrated perspective to guide the development of more advanced CH4 modeling tools for rice agricultural systems.

Global greenhouse effect and the increase of CO2 concentration in the atmosphere make harmful cyanobacterial blooms occur frequently. Understanding the inherent laws and influencing factors of cyanobacterial blooms is the key to hinder their development and maturity. Previous studies have focused on limiting the development of cyanobacteria by changing external environmental factors, ignoring the internal factors among microorganisms in the cyanobacteria bloom. Based on the ecological regulation strategies aimed at regulating the life activities of cyanobacteria and the succession of cyanobacterial blooms, we discuss the non-negligible role of quorum sensing in the formation of cyanobacterial blooms. The promo­tion effect of QS on the growth and development and competitive advantage phenotype of pure cyanobacteria was analyzed, and the potential influence of QS as an internal driving force for community succession of cyanobacteria was reasonably speculated. Although there are few studies on the regulation of QS as a control strategy for algal blooms. Here, we provide detailed information on the possible effects of QS on cyanobacteria and on the actual cyanobacterial bloom community, and the importance of QS in the formation of cyanobacterial blooms was emphasized. In addition, the previous studies on cyanobacterial QS are critically analyzed, the puzzling problems in these studies are put forward, and more perfect suggestions for future work are provided.