Environmental Research最新文献

Seagrass beds are key blue-carbon ecosystems, yet their resilience is increasingly challenged by microplastic (MP) pollution and marine heatwaves (MHWs). We experimentally tested how these stressors, alone and combined, affect the seagrass Zostera marina (eelgrass) using a controlled mesocosm experiment grounded in multiple-stressor and trait-based ecological theory. Plants were grown for 43 days in sediments with or without polyethylene/polypropylene MPs and a simulated MHW, (+5°C for 15 days) was imposed in the final phase. MP exposure significantly reduced rhizome elongation (-35%), total root length (-65%), and below-ground biomass, and depleted non-structural carbohydrates (NSC) in leaves and rhizomes (-35% to -40%). Warming alone stimulated leaf growth but further reduced NSC, while the MP × MHW interaction produced the lowest below-ground growth and carbohydrate reserves, consistent with synergistic stress predicted by multiple-stressor theory. MP exposure also reshaped the microbiome enriching putative sulfur-cycling taxa in the rhizosphere and indicating more reducing sediment conditions. With a carbon-balance and holobiont framework, MPs appear to constrain resource supply (oxygen and nutrients) and increase maintenance costs, whereas warming amplifies metabolic demand. The resulting carbon deficit limits below-ground growth, traits that underpin restoration success and blue-carbon function. These findings show the importance of incorporating microplastic monitoring into seagrass management to anticipate cumulative stress under a warming ocean.

This study investigates sediment contamination related to emerging contaminants (ECs) in the marine environment of the Red Sea, a cornerstone of the Kingdom of Saudi Arabia's economic development. Sediment samples were collected throughout the Red Sea coastal and deep areas, to assess the occurrence, distribution, possible sources, and transport pathways of ECs. This is the first geographically comprehensive study of ECs in the Saudi Arabia's coastal and deep Red Sea marine environment, including the most important coastal hotspots and employing cutting-edge novel analytical techniques. This work provides useful insights to legislative parties in the framework of the Marine and Coastal Environment Protection Initiative (MCEP) for the assessment of the marine environment of the Red Sea. Generic sample preparation protocols were applied to extract a broad range of LC-amenable semi-polar to polar ECs and a hybrid trapped ion mobility tandem high resolution mass spectrometric technique was utilized. Subsequently, wide-scope target screening of more than 3100 ECs was conducted. In total, 55 ECs were determined belonging to 7 distinct chemical classes, including pharmaceuticals, pesticides, per- and polyfluorinated alkyl substances (PFAS), industrial chemicals, etc. The highest contaminant concentrations were found in Jeddah Mena and Jeddah Lagoon regions, with cumulative concentrations of ECs reaching up to 3.96 mg/kg d.w. and 10.77 mg/kg d.w., respectively, while some specific contaminants (e.g. PFOS, phthalates) were detected in the deep sediments of the Red Sea. Risk assessment showed that 12 compounds were at high ecological risk, highlighting the need for comprehensive monitoring of the coastal area.

Pesticide contamination poses a substantial threat to human health. Existing evidence has linked exposure to imidacloprid (IMI) with lipid metabolism disorders. Nevertheless, the mechanisms mediating IMI-induced aberrations in hepatic lipid metabolism and hepatocyte senescence remain incompletely elucidated-particularly the long-term impact effects of exposure at human-relevant doses, which are even less well characterized. To fill this research gap, we conducted a 24-week drinking water exposure experiment in mice using human-relevant doses of IMI (0, 0.015 μg/mL, 0.52 μg/mL, 0.033 mg/mL) to investigate the resulting hepatic lipid metabolism abnormalities and the regulatory role of hepatocyte senescence in this pathological process. Toxicological analyses showed that IMI exposure led to liver function impairment and histopathological changes in mice, induced abnormal hepatic lipid metabolism (p<0.05), and upregulated the expression of senescence-associated proteins in mice (p<0.05). Mechanistic investigations further revealed that the cGAS-STING pathway may mediate hepatocyte senescence, and inhibition of this pathway in HepG2 cells markedly alleviated cellular lipid metabolic disorders and senescence (p<0.05). The findings of this study demonstrate that IMI exhibits chronic hepatotoxicity at human-relevant exposure levels, emphasizing an urgent need for additional toxicological investigations based on human-relevant exposure levels to comprehensively evaluate the toxicity profile of neonicotinoids.

Using metakaolin (MK) as a supplementary cementitious material (SCMs) to enhance the early strength of supersulfated cement (SSC) is a feasible strategy. The effects of 0-30 wt% MK on the hydration thermodynamics, flowability, setting time, and mechanical properties of supersulfated cement (SSC) were evaluated. Characterization techniques, including ICC, XRD, FTIR, TG-DTG, and SEM-EDS, provided insight into how MK influences the performance and microstructural evolution of metakaolin-supersulfated cement (MSSC). The results indicate that MK accelerates the early hydration rate of MSSC by providing additional nucleation sites. The optimal MK content was found to be 25 wt%, with compressive strengths reaching 18.7 MPa at 3 d and 42.4 MPa at 28 d, reaching 122.22% and 208.87% of the MK0, respectively. Additionally, the pozzolanic activity of MK facilitated the formation of ettringite (AFt) and calcium aluminosilicate hydrate (C-(A)-S-H) in MSSC. By adjusting the Ca/Si and Al/Si ratios, the C-(A)-S-H structure was optimized, resulting in a denser matrix pore structure. These findings were further supported by phase composition and microstructure analyses. However, when the MK content reached 30 wt%, its excessive addition limited its reactivity due to insufficient portlandite in MSSC, leading to reduced compressive strength. This study identifies 25 wt% MK as the optimal dosage for enhancing SSC performance, improving early strength, and maintaining environmental sustainability.

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.

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.

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 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.