Environmental Research最新文献

The agricultural reuse of wastewater is a crucial solution to water scarcity, especially in arid and semi-arid regions. However, microbial contamination poses significant health risks, necessitating a better understanding of pathogen survival in natural environmental conditions. This study aimed to investigate the survival dynamics of key enteric bacteria, Escherichia coli, Salmonella enterica, Enterococcus faecium, alongside viral particles, including human adenovirus (HAdV) and a double stranded DNA somatic coliphage, in soil under real-world semi-arid conditions across two distinct seasons. The study further examined the influence of critical environmental variables, including temperature, relative humidity, and ultraviolet (UV) radiation intensity, on microbial survival. Die-off rate constants (k) were calculated to quantify microbial inactivation, and predictive models were developed using adaptive neuro-fuzzy inference system (ANFIS). E. coli and S. enterica exhibited the fastest die-off rates, while E. faecium demonstrated persistence comparable to viral indicators. Coliphage showed the highest T90 value, closely resembling that of HAdV, supporting its use as a reliable surrogate for adenovirus. UV radiation, elevated temperature, and low humidity significantly accelerating microbial die-off. ANFIS models demonstrated high predictive accuracy in estimating die-off rates based on environmental variables. These findings highlight the importance of semi-arid climatic conditions in rapid die-off rate of microorganisms in soil. However, the prolonged survival of microorganisms during winter warrants greater attention to mitigate potential public health risks associated with the agricultural reuse of wastewater. Overall, the results emphasize the importance of environmental context in ensuring the safe agricultural reuse of wastewater and in refining microbial risk assessment frameworks.

Short-chain fatty acids (SCFAs) production from sludge fermentation is frequently constrained by substrate accessibility and hydrolysis efficiency. While sulfate radical-based pretreatment shows promise for enhancing SCFAs production, the performance differences and mechanisms of different iron sulfides remain unclear. In this study, three iron sulfide polymorphs (FeS₂, Fe₃S₄, and Fe₇S₈) activated sulfite were employed to enhance SCFAs production from waste activated sludge (WAS) during fermentation. Fe₃S₄ contributed to the highest SCFAs yield at 111.4 ± 11.0 mg COD/g VSS (4 d) with acetate proportion exceeding 80%, increased by 2.1 and 1.3 folds than control and FeS₂/Fe₇S₈ groups. Mechanistic analysis elucidated that the mixed-valence structure of Fe₃S₄ facilitated the superior sulfite activation efficiency (94.7% consumption) and high oxidative radical generation (SO₄^-·/·OH), enabling the effective extracellular polymeric substance (EPS) disruption without excessive oxidative stress on enzymes. Functional microbes, including hydrolytic bacteria (e.g., Pseudarcobacter) and acidogens (e.g., Macellibacteroides, Escherichia-Shigella) were selectively enriched in the pretreatment groups, and showed the underlying cooperation relationship. This work proposes a novel strategy for low-cost and high-efficiency pretreatment for SCFAs production during sludge fermentation, providing the theoretical and technical support for the future implementation in wastewater treatment plant.

Biochar (BC) attracts considerable interest owing to its high specific surface area and interconnected porosity. Here, magnetic biochar (CoFe₂O₄@BC) was synthesized via a co-precipitation-calcination route and applied to activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) abatement. The composite exhibited a markedly increased Brunauer-Emmett-Teller surface area (from 3.6 to 96.7 m² g^-1) and well-dispersed spinel CoFe₂O₄, as confirmed by TEM, SEM, XRD, XPS, and FTIR. Under optimized conditions (CoFe₂O₄:BC = 1:2; [catalyst] = 0.20 g L^-1; [PMS] = 0.20 g L^-1; initial pH = 7), the CoFe₂O₄@BC/PMS system removed >97% SMX within 15 min with an apparent rate constant k_obs ≈ 0.20 min^-1. Radical-quenching tests (MeOH, TBA, p-BQ, L-histidine) and EPR (DMPO/TEMP) indicated the coexistence of radical (SO₄•^-, •OH, O₂•^-) and non-radical (¹O₂) pathways, with ¹O₂ predominating. Coexisting constituents imposed limited interference (Cl^-, NO₃^-, humic acid), whereas HCO₃^- notably suppressed kinetics (kobs down to ∼0.062 min^-1 at high concentration). LC-MS/MS resolved transformation products consistent with S-C/C-N scissions and ring opening, and density functional theory (DFT, Gaussian 16) highlighted susceptible sites on SMX; ECOSAR screening suggested mixed intermediate toxicity that diminished as degradation proceeded. These results identify CoFe₂O₄@BC as an efficient PMS activator for antibiotic abatement in water.

The preparation of composite cement using alkali-ground coal gasification slag (CGS) exhibits significant potential for promoting solid waste utilization while reducing energy consumption and carbon emissions. However, the mechanisms governing CGS activity enhancement during alkali grinding and its subsequent influence on hydration behavior and property evolution of composite cements remain insufficiently understood. In this study, a series of CGS-based composite cement samples with graded performance were prepared by regulating alkali grinding parameters. The intrinsic relationships among CGS activation, hydration behavior, microstructural evolution, and mechanical properties were systematically investigated from both optimization and degradation perspectives. The results indicate that alkali grinding effectively activates the latent reactivity of CGS. The introduction of an appropriate amount of sodium hydroxide during alkali grinding significantly promotes cement hydration and accelerates the nucleation and crystal growth of hydration products, whereas excessive sodium hydroxide inhibits hydration. Consequently, the compressive strength of the composite cement initially increases and then decreases with increasing sodium hydroxide dosage. The 28 d compressive strength of the SH-2 group reaches 46.8 MPa, representing a 32.20% improvement compared with the SH-0 group. The dominant hydration products consist of AFt and highly polymerized C-(A)-S-H gels, which markedly enhance matrix densification. Compared with conventional cement, the SH-2 group exhibits reductions of 16.17% in sustainability index (SI), 19.84% in cost, and 14.71% in economic index (EI). These findings provide a mechanistic basis for the rational utilization of CGS in composite cements and offer valuable insights for the synergistic development of solid waste resource utilization and sustainable construction materials.

The persistent nature of dense non-aqueous phase liquids (DNAPLs) in soil-groundwater systems represents a critical environmental challenge, with conventional bioremediation approaches limited by dual constraints: inadequate bioavailability and insufficient microbial metabolic capacity. Here, we present a novel remediation paradigm that simultaneously addresses these mechanistic bottlenecks through sonoporation-mediated in-situ gene transfer. This approach leverages acoustic cavitation to enhance phenanthrene (PHE) phase transfer while facilitating targeted delivery of dioxygenase genes from a PHE-degrading strain (Pseudomonas sp. PHE) to indigenous soil bacteria (Mesobacillus sp. Z). In comprehensive phase-specific degradation experiments, the combined sonoporation-DNA treatment (SD) achieved 98.16% dissolved phase degradation within 12 days, representing a 26.5% improvement over natural attenuation, while reducing the half-life by 43% (from 6.19 to 3.53 days). Mechanistic investigation revealed that sonoporation enhanced PHE partitioning from non-aqueous to dissolved phases by more than 30%, while qPCR analysis verified successful gene acquisition and expression in the transformed indigenous strains. This synergistic approach fundamentally reframes DNAPL remediation by integrating physical mobilization with functional genetic enhancement, effectively decoupling remediation efficiency from native microbial limitations. The method provides a high physiological compatibility, additive-free alternative to conventional bioaugmentation, with broader implications for persistent organic pollutant remediation strategies that prioritize ecological integrity and operational sustainability.

Environmental exposures can shape microbial community compositions inside homes. Metagenomic sequencing methods can further elucidate the role of household exposures like indoor moisture and the surrounding landscape. To identify household environmental exposures associated with the house dust metagenome. Microbial communities in vacuumed dust from 771 homes in the Agricultural Lung Health Study were characterized using whole metagenome shotgun sequencing (5,821 taxa across 45 phyla). Household characteristics (i.e. presence of leaks, de-humidifier, humidifier use) were assessed by questionnaires or field technicians. We evaluated associations between exposures and both overall microbial diversity and differentially abundant taxa (ANCOM-BC2). Additionally, we explored microbial networks based on Spearman correlations (SECOM). Microbial diversity was higher in homes with mold/mildew (p-value<0.05), leaks, humidifier use, or occupants removing shoes before entering (p-value<0.1). Examining individual species, <10 taxa were significantly differentially abundant (p-value<0.05 after Holm-Bonferroni correction) in relation to both mold/mildew and leaks. Greater than 10 species were significantly differentially abundant in relation to removing shoes and humidifier use. Additionally, the genera Clostridium, Prevotella, and Cryptobacteroides were positively associated with removing shoes. In this farming population, the house dust microbiome differed by moisture-related exposures, and removing shoes before entering the home. Many novel associations were identified between individual taxa and these exposures. Our findings further knowledge of the impact of environmental conditions inside the home on the indoor microbiome.

Insects represent the most diverse and abundant animal group on Earth and play a key role in transferring pollutants from primary producers to higher trophic levels. This study investigated the concentrations of polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), dichlorodiphenyltrichloroethanes (DDTs), and hexachlorocyclohexanes (HCHs) in ten insect species collected from an agricultural region in the North China Plain. Total HCH concentrations in insects were significantly higher than those of other halogenated organic pollutants (HOPs), with ground beetles presenting the highest HCHs levels, suggesting that agricultural activities as the predominant contamination source. Species-specific congener profiles were observed for DDTs, while other HOPs were dominated by CB 28, CB 187, BDE 209, and β-HCH. Fossorial insects had the highest HOPs concentrations, followed by aquatic and terrestrial species. Additionally, omnivorous insects accumulated more HOPs than most phytophagous and carnivorous ones. These findings highlight the role of habitat and feeding strategy in shaping pollutant bioaccumulation patterns, providing valuable insights into contaminant cycling within agricultural ecosystems.

Although microalgae-fungi consortia (MFCS) have emerged as a sustainable strategy for swine effluent remediation, the mechanistic link between extracellular polymeric substances (EPS) evolution and aggregate stability is not fully understood. In this study, efficient MFCS were developed using Scenedesmus obliquus, Chlorella pyrenoidosa, and Chlorella vulgaris co-cultivated with Aspergillus niger. The S. obliquus-A. niger consortium achieved the best performance, achieving superior removal efficiencies for total phosphorus (TP, 89.93%), chemical oxygen demand (COD, 79.36%), and total nitrogen (TN, 73.85%). Physiological analyses revealed that high ammonia nitrogen stress in monocultures triggered severe oxidative damage, evidenced by 55-62% higher SOD/CAT activities and 56% higher MDA content compared to co-cultivation systems. Fungal co-cultivation increased EPS production by approximately 40% compared with the monoculture system and induced the formation of protein-rich, humic-like macromolecules enriched with carboxyl and carbonyl groups. These compositional changes enhanced EPS viscoelasticity and cohesion, resulting in compact algal-fungal granules with high structural stability. Techno-economic assessment revealed a total treatment cost of 0.304 USD/m³, which is comparable to conventional activated sludge treatment (∼0.30 USD/m³). However, the system distinguishes itself by eliminating sludge disposal costs, highlighting its cost-effectiveness for swine wastewater management. Overall, this study elucidates the EPS-mediated aggregation mechanism and demonstrates the feasibility of MFCS as an energy-efficient and economically sustainable strategy for swine wastewater management.

Inland water networks, comprising hydrologically integrated rivers, agricultural ditches, and aquaculture ponds, are significant N₂O sources, yet their complexity impedes accurate quantification. Here we developed an integrated framework combining structural equation modeling (SEM), machine learning (ML), and SHapley Additive exPlanations (SHAP) to bridge causal inference with nonlinear predictive modeling in China's Taihu Basin. Our results demonstrate that NO₃^--N and water temperature (WT) dominate N₂O variability, explaining significantly more variance than discrete water body categories. This framework successfully reconciled the dual role of dissolved organic carbon (DOC). SEM identifies DOC as a macroscopic sink driven by the complete denitrification of nitrate to N₂ (standardized effect = -0.143), while SHAP reveals its role as a microscopic catalyst that enhances N₂O production efficiency per unit of nitrate. Although the ensemble model achieved high accuracy (test R² = 0.70), the parsimonious model using four routine parameters (NO₃^--N, DO, NH₄⁺-N, and WT) proved more suitable for regional assessment, demonstrating satisfactory predictive capability (test R² = 0.54) and successfully reconstructing basin-wide spatiotemporal patterns. This study provides a scalable and transferable methodology for unlocking the driving mechanisms of complex aquatic ecosystems, offering a robust tool for basin-scale N₂O estimation and targeted greenhouse gas mitigation.

This study quantifies structure-property relationships in surfactant-foamed porous metakaolin-based geopolymers, linking pore architecture to methylene blue (MB) adsorption, thermal insulation, compressive strength, and filtration. MB is used here as a representative cationic organic probe to elucidate the coupling between pore connectivity and mass-transfer/adsorption kinetics. Sixteen formulations were prepared using H₂O₂ (2 wt%) as the foaming agent and either sodium dodecyl sulfate (SDS, 1.6-3.0 wt%) or vegetable oil (3.0-6.0 wt%) as stabilizers under ambient and 60 °C curing. Surfactant-containing systems exhibited total porosity >70%; in SDS systems, open porosity typically exceeded 85% of the total. Thermal conductivity spanned 0.125-0.54 W/(m·K); unfoamed matrices were 0.5311 W/(m·K) (ambient) and 0.45 W/(m·K) (60 °C), whereas foamed samples predominantly fell within 0.10-0.30 W/(m·K). Bulk density and conductivity followed a strong linear relation. The unfoamed matrix exceeded 50 MPa at 3 d and 60 MPa at 28 d; H₂O₂ foaming reduced strength substantially, consistent with increased porosity. Enhanced pore connectivity accelerated adsorption kinetics: the matrix required >200 min to equilibrate, H₂O₂-only specimens equilibrated within 60 min, and SDS-modified specimens (1.6-2.3 wt%) within 20 min. Under 2 wt% H₂O₂ + 2.3 wt% SDS at 60 °C, maximum MB uptakes reached 0.212/0.455/0.906 mg/g at initial concentrations of 10/20/40 mg/L, respectively. While MB served as the model adsorbate, intended engineering deployments focus on contaminants prevalent in urban stormwater-specifically selected hydrophobic organics-and thus prioritize use as pre-treatment media in inlet vaults, filter layers within permeable pavement bases, and rooftop runoff modules. In such installations, low thermal conductivity can help buffer seasonal temperature swings, while the quantified links between pore connectivity and flux and between density and conductivity provide design guidance for multifunctional geopolymers that integrate adsorption, filtration, and insulation.