Rubber products are widely used in transportation, construction, and electronics. At the same time, concern is growing over the environmental and human health risks of rubber additives. However, systematic screening is still limited because few workflows link hazard information with industrial formulation loading data. Here, we developed an integrated high-throughput screening workflow for rubber additives by harmonizing multiple authoritative databases to compile chemical structures, functional information, and representative formulation data. Multi-model and multi-endpoint quantitative structure–activity relationship (QSAR) predictions were integrated using two hazard-ranking strategies, and additional substances of concern were identified using criteria spanning persistence (P), bioaccumulation (B), mobility (M), and toxicity (T). Hazard-based screening identified 82 priority chemicals. For 12 specific rubber additives with publicly accessible formulation ranges, we further incorporated representative formulation loading and a molecular-weight-based migration potential metric. This step produced an exposure factor and an integrated Risk Index (RI). Under exposure-informed conditions, 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), and N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD) were identified as top-priority additives by the integrated assessment. Overall, this framework improves the practical relevance of additive prioritization, thereby supporting greener material design, risk management, and substitution assessment in the rubber industry.
Standard models for assessing the acute health effects of environmental exposures assume that risks from daily exposures are additive, ignoring “cascading effects” where prior events modify an individual's vulnerability. Here, we introduce and validate the Interactive Distributed Lag Model (iDLM), which quantifies these dynamics by incorporating interaction terms between exposures at different lags. Simulation studies confirm that traditional models are biased when cascading effects are present, whereas the iDLM accurately recovers the true risk structure. We applied this model to a nationwide U.S. dataset to analyze the mortality risks of short-term exposure to PM2.5 and O3. Consistent with the standard models, the iDLM shows that short-term exposure to PM2.5 or O3 is significantly associated with increased risk of all-cause mortality. For each 10-μg/m3 increment in PM2.5 and 10-ppb increase in O3 on the day of exposure, the risk of all-cause mortality increased by 0.26% (95% confidence interval [CI]: 0.12, 0.40) or 0.18% (95% CI: 0.11, 0.24), respectively. We find that PM2.5 exhibits a strong, synergistic amplification effect, while the cascading effects of O3 are weaker. Critically, we demonstrate that for both pollutants, a substantial component of the mortality burden appears to be driven by cascading interactions, which are largely overlooked by traditional models. These findings fundamentally reframe the understanding of air pollution's public health impact, revealing that the history-dependent dynamics of vulnerability, not just independent daily insults, are a crucial mechanism of harm.
Formaldehyde (HCHO) is a globally distributed ambient air pollutant associated with respiratory disease, cancer, and premature mortality, with evidence of adverse health effects even at low ambient concentrations. As a major oxidation product of volatile organic compounds, atmospheric HCHO is strongly affected by natural sources such as vegetation and wildfires, which are highly sensitive to temperature and drought. However, its response to climate warming remains poorly constrained. Here, we develop a deep learning framework that extracts empirical climate sensitivities from more than a decade of daily satellite observations to project how ambient formaldehyde will evolve in a warming climate. We estimate that global mean HCHO increases by approximately 2.3% per degree of warming, largely associated with enhanced biogenic and wildfire emissions. Approximately one-fifth of the global population is already exposed to potentially risky HCHO concentration levels under present-day conditions. Climate-driven increases are projected to substantially expand this exposure burden. Under a mid-range emissions scenario (SSP2-4.5), global person-month exposure to concentrations exceeding 5 ppb approximately doubles by the end of the century. The largest increases occur in Africa and South America, while exposure in Human Development Index (low-HDI) regions globally rises by more than a factor of three, indicating a pronounced amplification of environmental inequality. We further suggest that warming-driven increases may contribute to higher cancer-related health concerns in these regions. Our findings identify formaldehyde as a climate-sensitive yet under-recognized health-relevant pollutant and show that warming amplifies this neglected exposure burden and widens global environmental inequality.
Adverse outcome pathways (AOPs) describe toxicity across levels of biological organization by measurable key events (KEs), thus providing a structured framework for predicting population-level effects. Here, mussels were exposed to different temperature conditions-22 °C and marine heatwave (MHW), in combination with nano-titanium dioxide (nano-TiO2) at 0, 25, and 250 μg/L. High-concentration nano-TiO2 and MHW exposure promoted the secretion of byssal threads and enhanced the adhesion to the substrate. However, they also caused severe histopathological damage in the foot and reduced the condition index (CI), indicating serious organism-level adverse outcomes (AOs). Accumulation of lipid peroxidation (LPO) products and redox imbalance suggested that MHW and nano-TiO2 induced oxidative stress, leading to increased cell apoptosis (CA), reduced cell viability (CV), and consequent tissue damage in the foot. Nano-TiO2 and MHW exposure significantly upregulated adhesion-related genes (Mfp-3/5/6) as well as immune- and cytotoxicity-related genes (Caspase-3, TLR-4, Myd88, and TNF-α). In contrast, Mfp-1/2/4 and pre-collagen proteins (preCOL-D/P/NG) were significantly downregulated, resulting in poor extensibility of byssal threads. Using the AOP framework, this study links nano-TiO2 toxicity and MHW-induced stress to molecular disruptions, organism-level adverse outcomes, and altered mussel byssal defenses. These findings highlight that the interaction between MHW and nanoparticles may compromise mussel attachment and survival, with potential implications for the stability of coastal benthic ecosystems under future climate change scenarios.
As an effective control strategy, optimizing operational parameters of wastewater treatment processes prior to disinfection can reduce disinfection byproduct (DBP) precursors, thereby controlling DBP formation and associated biotoxicity. For the widely applied tertiary post-denitrification process, however, the effectiveness and underlying mechanisms of two key parameters-the carbon-to-nitrogen (C/N) ratio and hydraulic retention time (HRT)-in controlling DBPs and biotoxicity remain unclear. In this study, the formation of 32 halogenated DBPs and adsorbable organic halogen (AOX), as well as the acute toxicity of luminescent bacteria, were investigated under different C/N ratios (3-6) and HRTs (7-24 h). Results showed that HRT had a more pronounced effect than the C/N ratio on DBPs, AOX, and toxicity. At 30 °C with a C/N ratio of 6, extending HRT from 7 h to 24 h reduced carbonaceous DBPs, nitrogenous DBPs, AOX, and toxicity by 73%, 45%, 19%, and 17%, respectively. Correlation analyses suggested that AOX exhibited a significant positive linear correlation with the total fluorescence intensity of post-denitrifying effluents, and that tryptophan-like and humic-like components were identified as primary precursors of AOX. Additionally, AOX was found to be the main toxicity driver. Based on established linkages between operational parameters, microbial communities, and fluorescence components, a sequential pathway was proposed: operational parameters (primarily HRT) regulate specific microbial taxa, which mediate fluorescent precursor production, further influence DBPs and AOX formation, and ultimately affect biotoxicity. This pathway preliminarily provides actionable guidance from engineering and microbiological perspectives for the source control of DBPs and biotoxicity in chlorinated wastewater.
Water movement activates a hidden hydrogen-driven energy pathway that converts hydrodynamic forces into electrons and reactive oxygen species, directly powering microbial metabolism while simultaneously driving abiotic pollutant degradation. This hydro-electric mechanism reveals a previously overlooked engine of natural water purification that operates beyond sunlight or chemical inputs. Recognizing and harnessing this intrinsic energy flow is essential for protecting water quality at its source, reinforcing ecosystem resilience, and safeguarding human health—pointing toward a new frontier of nature-based sustainable environmental management strategy.
Understanding the fate and transformation of antibiotics is essential for controlling antibiotic pollution in wastewater treatment plants (WWTPs). This study integrated metagenomics, metaproteomics, molecular dynamics (MD) simulations, and pathway analysis to elucidate the behavior of ciprofloxacin (CIP), sulfamethoxazole (SMX), and roxithromycin (ROX) under single- and mixed-antibiotic exposures in an activated sludge system. Fate analysis revealed divergent pathways: SMX was predominantly biodegraded (>70%), whereas CIP and ROX were mainly adsorbed onto sludge, showing poor removal and high effluent residuals (CIP > 50%, ROX > 60%). Under mixed-antibiotic stress, microorganisms favored lower-energy degradation pathways, leading to simplified (skip-step) transformations. MD simulations unveiled that within the extracellular polymeric substances (EPS) matrix, the protein fraction exhibited the strongest binding. Docking and MD simulations on a proteomics-derived interface-associated protein (OmpA) revealed a co-adsorption behavior under mixed-antibiotic exposure, where CIP strongly anchored through multipoint hydrogen bonding/electrostatic interactions and facilitated SMX stabilization in the same pocket via aromatic stacking. Multi-omics analyses revealed a microbial “survival-first” strategy dominated by resistance and repair. Notably, transporter-related stress responses were prominent under mixed stress, and several ABC transporter-associated components (e.g., K02003/K02004 and K02033) were negatively correlated with removal efficiency, coinciding with reduced degradation by key genera such as Micropruina and Ottowia. Under mixed-antibiotic stress, a confluence of reinforced resistance (e.g., Type IV secretion system K03205), altered EPS binding, and skewed energy allocation (e.g., downregulation of cofactor synthesis ko01240) led to incomplete degradation and widespread persistence. This study provides a multiscale theoretical framework for optimizing WWTPs to control antibiotic pollution.
Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants with potential reproductive toxicity, yet their profiles in follicular fluid and impacts on human fertility remain unclear. Given the importance of diet as an exposure pathway, we aimed to characterize PFAS in follicular fluid, examine associations with reproductive outcomes, and explore dietary contributors across regions in China. In this multicenter study involving 1301 women undergoing assisted reproductive technology in eight administrative divisions, 20 PFAS were quantified in follicular fluid. Reproductive outcomes included live birth, pregnancy loss, and early measures of ovarian hormones, endometrial thickness, and oocyte or embryo development. Associations were estimated using center-specific regression models combined by meta-analysis, with false discovery rate (FDR) correction. Both legacy and emerging PFAS were detected, with perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid contributing 19%-40% and 23%-37% of total concentrations, respectively, and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) 11%-19%. Concentrations were higher in eastern and southern centers. Higher PFOS concentrations were significantly associated with an increased risk of biochemical pregnancy loss after FDR correction (RR per natural-log-unit increase: 2.10; 95% CI: 1.28, 3.45). Several legacy PFAS were linked to lower luteinizing hormone, elevated progesterone, and thinner endometrium on the day of human chorionic gonadotropin. Comparable associations were observed for emerging PFAS. Dietary intake of aquatic food and other animal-derived foods correlated positively with PFAS concentrations. These findings highlight PFAS accumulation in the ovarian microenvironment and potential disruption of early reproductive processes, underscoring the need for exposure mitigation through modifiable dietary pathways.
Microbial-mediated dark carbon fixation (DCF) is increasingly recognized as an important process for primary production in global oceanic ecosystems, with ammonia oxidation (AO) providing a major energy source for DCF in oxygenated waters. However, a significant research gap remains in integrating the DCF and AO processes mediated by ammonia-oxidizing archaea (AOA) and bacteria (AOB) into a systematic framework within estuarine ecosystems. In this study, we investigated the DCF and AO rates in water samples from the Yangtze Estuary through incubation experiments with 14C and 15N isotope probing techniques. The measured DCF and AO rates ranged from 17.58 to 168.70 nM C/h and from 4.78 to 499.63 nM N/h, respectively. Our results revealed significant positive correlations among DCF rates, AO rates, and ammonium concentrations. Amplicon sequencing revealed that chemoautotrophs utilizing the Calvin-Benson-Bassham (CBB) cycle were predominantly affiliated with Burkholderiales, while those utilizing the 3-hydroxypropionate/4-hydroxybutyrate (3-HP/4-HB) cycle were primarily associated with Nitrosopumilaceae. Temperature played a crucial role in shaping the composition of chemoautotrophic communities harboring the CBB cycle, whereas salinity was a key factor modulating the composition of chemoautotrophic communities harboring the 3-HP/4-HB cycle. Niche differentiation within nitrifier communities enables their effective adaptation to the frequent environmental fluctuations characteristic of estuarine ecosystems. This study highlights the ecological significance of DCF driven by ammonia oxidation in estuarine waters and emphasizes the need to integrate DCF into blue carbon assessments in coastal ecosystems.
Antibiotic resistance poses considerable risks worldwide due to its threats to human health and ecosystem stability. Notably, aquatic ecosystems are recognized as reservoirs of antibiotic resistance contaminants. Therefore, developing effective strategies to mitigate antibiotic resistance in aquatic environments is urgently required. Herein, a cobalt single-atom-crystalline carbon nitride (Co-CCN) catalyst was fabricated and employed to activate peroxymonosulfate (PMS) for antibiotic-resistant bacteria (ARB) inactivation and antibiotic-resistance genes (ARGs) elimination. Notably, the Co-CCN/PMS system attained approximately 6-7-log inactivation of diverse ARB within 20 min, and ARB membrane disruption was further verified based on cellular morphology imaging and protein leakage measurements. Additionally, the removal efficiency of tetA exceeded a 4-log reduction within 120 min. Electron paramagnetic resonance (EPR) and quenching tests confirmed that the Co-CCN/PMS system generated •OH, SO4•-, •O2 -, and 1O2 for highly efficient ARB inactivation and ARG removal. Besides, the Co-CCN/PMS system also demonstrated exceptional environmental robustness and high efficiency for treating real water. Density functional theory (DFT) calculations indicated that single Co atoms adsorb oxygen atoms from PMS via electrostatic interactions, accompanied by electron transfer from Co-CCN to activate PMS. Our findings provide atomic-level insights into PMS activation for mitigating antibiotic resistance in aquatic settings.
Perfluoroalkyl substances (PFAS) pollution has been a worldwide environmental challenge. Inspired by the semipermeable function of cell membranes, we constructed a millimeter-sized capsule adsorbent with specific molecular recognition capability to capture a broad spectrum of PFAS. This novel capsule consists of a core with a regulated nanoscale amine-rich network powder (ANP) and a porous polyvinylidene fluoride (PVDF) shell. Adsorption experiments and molecular simulations revealed that the PVDF shell acted as a semipermeable membrane, allowing only PFAS to pass through while repelling the coexisting environmental matrices, whereas the ANP core could provide the driving force for PFAS to enter the interior of the capsule adsorbent. Moreover, by regulating the hydrophilic functional structure of ANP, the driving force for short-chain PFAS to enter the capsule interior was enhanced, enabling the efficient capture of a wide range of PFAS (C-F number: 3-9). Further mechanistic studies demonstrated that the dual driving forces based on fluorophilicity and hydrogen bonding were key to capturing broad-spectrum PFAS. The fixed-bed experiments further demonstrated that the aminated organic fluorine capsule (AFC) column could treat approximately 18,000 bed volumes of effluent from synthetic PFOA-polluted water, with the effluent PFOA concentration remaining below 40 ng/L from an initial influent concentration of 1 μg/L (compared with the World Health Organization's drinking-water standard of 100 ng/L). Overall, this work not only provides a promising approach to treat PFAS-containing water but also sheds light on the design of functional remediation materials based on molecular properties and confined structures.
Screening microorganisms capable of efficiently degrading chloramphenicol (CAP) is critical for remediating CAP-contaminated soils. However, few bacterial strains capable of catabolizing CAP have been identified as suitable for soil application, and the metabolic and genetic mechanisms of CAP degradation remain poorly understood. Herein, Nocardia testacea CS1 was isolated for its ability to utilize CAP as the sole carbon source. CS1 exhibited substantial CAP mineralization and broad environmental tolerance across temperatures of 15-50 °C and pH values of 4-11. Integrated analyses of intermediate products, gene clusters, and transcriptomes revealed a proposed CAP catabolic pathway. The chloramphenicol degrading (chd) gene cluster was proposed to mediate sequential CAP transformation, including initial oxidation (ChdB), amide hydrolysis (ChdD), β-cleavage (ChdC), and transcriptional regulation (ChdR). Downstream nitroaromatic intermediates were further reduced by PnbAB and assimilated into central metabolism. Bioaugmentation experiments demonstrated effective CAP removal in farmland soils, supported by successful colonization and biofilm formation of CS1. Sustained CAP degradation was accompanied by improved soil ecological health. The degradation capabilities of CS1 extend to thiamphenicol and selected para-substituted nitroaromatic pollutants, while no activity was observed toward florfenicol or ortho/meta-substituted nitrobenzoates, indicating structural selectivity. This study demonstrates substantial CAP mineralization by a soil-derived Nocardia testacea strain and identifies a chd gene cluster associated with CAP catabolism, providing mechanistic insights for the bioremediation of CAP-contaminated soils.
Wastewater treatment plant (WWTP) effluent is a significant source of environmental impacts, introducing substantial dissolved organic matter (DOM) and nutrients into receiving waters. However, the specific role of effluent-derived DOM (EDOM) in shaping microbial community structure and key metabolic functions remains insufficiently understood. We systematically explored the effects of EDOM on the seasonal dynamics of bacterial communities in effluent-receiving waters in a typical water-scarce region of North China. Our results revealed that WWTP effluent input significantly altered DOM characteristics, shifting them toward greater humification, increased recalcitrance, lower molecular mass, and simpler structure, against a background of elevated nutrient levels. The interplay between transformed EDOM and resident microorganisms collectively restructured the bacterial community and its potential metabolic functions. These changes included (i) increased taxonomic richness and a more specialized community composition; (ii) enhanced microbial network complexity with a polycentric architecture dominated by DOM components; (iii) seasonal convergence of microbial network structure, as strong EDOM-driven interactions in the dry season were attenuated by wet season hydrology; and (iv) strengthened coupling between DOM molecular traits and biogeochemical cycling potential. Crucially, EDOM was identified as the key driver controlling microbial richness and core metabolic processes, with its influence exhibiting significant seasonal dynamics across the carbon, nitrogen, and sulfur cycles. While current Chinese wastewater discharge standards regulate nutrient inputs, they lack consideration of ecological risks posed by EDOM fractions and their dynamic interactions with microorganisms. Our findings highlight the need to integrate EDOM characteristics into effluent risk assessments to improve WWTP discharge standards.
Biodegradation plays a crucial role in the removal of sulfonamides (SAs) from soils; however, the biodegradation pathways in soils and the impacts of soil organic matter (SOM) on SA biodegradation remain unclear. Here, we used [phenyl-U-14 C]-labeled SAs to investigate the degradation of sulfadiazine (SDZ), sulfamonomethoxine (SMM), and sulfamethoxazole (SMX) in a soil-free enrichment culture derived from an SDZ-degrading soil microbial community in the absence or presence of soil humic acids and artificial root exudates. The culture utilized the individual SAs as the sole carbon source and mineralized 60.4%-65.4% of the phenyl ring within 156 h, which was not inhibited by the antifungal actidione, suggesting a predominant bacterial contribution to the degradation. Several typical SA-degrading genera, including Achromobacter, Brevundimonas, Leucobacter, Micro-bacterium, Pseudomonas, and Rhodococcus, were enriched, and 16, 14, and 10 metabolites of SDZ, SMM, and SMX were identified, respectively. Twelve primary transformation pathways were proposed, including sulfonamide bond cleavage, desulfonylation, para-amino group modification, and heterocyclic moiety modification. Notably, the downstream transformation pathways of two desulfonylation products were elucidated, revealing their contributions to SA mineralization. The presence of additional organic matter, especially humic acids, significantly promoted the degradation and mineralization via covalent binding or co-metabolism, and substantially altered the dynamics and amounts of SA metabolites. Though biodegradation of SAs in soil can be much lower than in bacterial enrichment culture, our results provide insights into the complex SA transformation by soil microbial communities and the regulatory effects of SOM, with new implications for managing SA-contaminated environments.
The interaction between oxygen released from rice roots and reduced species in the surrounding soil matrix establishes the rice rhizosphere as a hotspot for the production of reactive oxygen species (ROS), thereby driving various critical biogeochemical processes. In this study, we observed that the concentration of dissolved Fe2+ in rhizosphere porewater exhibited pronounced temporal and spatial variations during the rice growth period, consistent with the dynamic patterns of ROS production. Iron plaque on the root surface facilitated the oxidation of dissolved Fe2+, leading to the production of hydrogen peroxide (H2O2) and hydroxyl radical (•OH) under acidic rhizosphere conditions (pH 5.5). Accordingly, rice roots with a higher content of iron plaque showed a stronger capacity to promote Fe2+ oxidation and ROS production. Iron oxides in the iron plaque (e.g., ferrihydrite, lepidocrocite, and goethite) rapidly induced the transformation of dissolved Fe2+ into surface-adsorbed and solid-phase Fe(II) and facilitated the oxidation of total Fe(II), thereby increasing the production rate and yield of •OH. These findings suggest that dissolved Fe2+ in rhizosphere porewater can serve as an electron donor, while iron plaque plays a crucial role in regulating iron redox cycling and ROS production in the rice rhizosphere.
