Volatile organic compounds (VOCs) are prevalent environmental pollutants posing significant risks to human health. However, their impact on thyroid function and the latent mechanism remain largely uncharted. This study utilized data of 1201 participants aged ≥20 years from National Health and Nutrition Examination Survey 2011-2012. Weighted generalized linear model (for single-analyte analysis) and quantile g-computation (QgComp) and Bayesian kernel machine regression (BKMR) (for mixture analysis) were employed to capture the individual and mixed effects of 16 VOCs metabolites (derived from 13 VOCs) on 10 thyroid function indicators. Network toxicology was employed to probe the underlying mechanism. In single-analyte effect analysis, we found several VOCs metabolites (e.g., N-Acetyl-S-(N-methylcarbamoyl)-L-cysteine [AMCC] and N-Acetyl-S-(2-cyanoethyl)-L-cysteine [CYMA]) were positively associated with thyroglobulin (hTg), negatively associated with free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyrotrophic thyroxine resistance index (TT4RI), TSH index, and thyroid peroxidase antibodies (TPO-Ab), while nae associated with total triiodothyronine (TT3), free triiodothyronine (FT3), total thyroxine (TT4), or thyroglobulin antibodies (anti-hTg). Both mixture models (BKMR and QgComp) discovered that the mixture of 16 VOCs metabolites was positively related to TT3 (β=0.0161; 95% CI: 0.0056∼0.0265) and FT3 (0.0077; 0.0020∼0.0134) while negatively related to FT4 (-0.0158; -0.0248∼-0.0067), TSH (-0.0395; -0.0726∼-0.0065), TT4RI (-0.0552; -0.0883∼-0.0221), TSH index (-0.0336; -0.0556∼-0.0117), and TPO-Ab (-0.1001; -0.2066∼-0.0056). Hypothesis-generating network toxicology showed a significant enrichment in interleukin-17 (IL-17) signaling pathway linking VOCs exposure and thyroid dysfunction. Conclusively, exposure of general adults to single VOC and particularly multiple VOCs mixture was associated with thyroid function alteration, and the possible (hypothesis-generating) mechanism may involve IL-17 signaling pathway.
Microplastic (MP) uptake and retention in freshwater invertebrates are shaped by both particle characteristics and feeding conditions, yet the specific influence of diet composition remains poorly understood. This study examined the concentration- and time-dependent ingestion, as well as depuration, of 45-53, 63-75, and 90-106 μm polyethylene MPs in adult Daphnia magna acclimated to three diets, with exposure assays conducted under either fed or unfed conditions. Concentration-dependent accumulation experiments were conducted at 4, 8, 40, 80, 400, and 800 mg/L for 48h. Time-dependent accumulation was assessed at 60 mg/mL for 60h. Depuration was measured for 6h following a 48h exposure to 60 mg/L. The experimental diets consisted of live Chlorella vulgaris, a dried spirulina and yeast mixture, or a combination of both. Concentration-dependent uptake followed Michaelis-Menten kinetics, with the smallest MPs retained in the highest numbers and food deprivation resulting in greater particle retention across all diets. Time-dependent uptake showed a sigmoidal trend shaped by MP size, diet type, and food availability. Depuration exhibited a reverse sigmoidal pattern, and D. magna acclimated to the live algae diet generally displayed more rapid MP clearance, indicating that prior dietary history influenced elimination. Together, these results indicate that MP ingestion and depuration in adult D. magna depend on both MP size and feeding conditions, and that diet composition plays a critical role in short-term MP fate. In conclusion, the present study suggests that feeding history and diet composition influence MP ingestion and depuration under controlled conditions and should be considered when designing and interpreting laboratory exposure studies.
Microplastics can move among terrestrial, aquatic, and atmospheric systems. However, the role of aquatic insects in transporting microplastics, and their potential contribution to cross-ecosystem transfer, remains poorly understood. In this study, we examined the accumulation of three microplastic types (polyethylene (PE) fragments, tire wear particles (TWPs), and polyacrylonitrile (PAN) fibres) in the merolimnic mayfly Cloeon dipterum. Larvae were exposed to two microplastics concentrations (500 and 5000 particles/L), and microplastics associated with larvae and newly emerged adults were quantified and characterized. All three microplastic types were detected in larval digestates, indicating their association with the organisms in the aquatic environment; however, ingestion and surface adhesion could not be distinguished. PE fragments were the most abundant (16-49 particles per larva), followed by TWPs (3-9 particles per larva), and PAN fibres (≤2 particles per larva). Microplastics were also found in both the washing water of emerged adults (representing surface-adhered particles) and their digestates (representing ingested particles), demonstrating that particles remained adhered to and inside the organisms after metamorphosis. Particle size analysis revealed preferential retention of smaller PE fragments and TWPs during both ingestion and adhesion, with the median size of recovered particles being 30-57% and 24-42% smaller, respectively, than that of the particles introduced into the system. Exposure to PAN fibres at the higher concentration (5000 particles/L) significantly reduced the time to 50% emergence by one day, whereas none of the treatments affected adult fatty acid profiles. Overall, our findings demonstrated that all three tested microplastic types can be associated with emerged aquatic insects, highlighting a potential pathway for the biologically mediated redistribution of microplastics. Further studies are needed to identify the mechanisms governing microplastic retention and to disentangle the effects of particle characteristics, such as polymer type, size, and shape, on these processes and their ecological significance.
Transformation of per- and polyfluoroalkyl substance (PFAS) precursors during drinking-water disinfection may generate persistent perfluoroalkyl acids (PFAAs), yet the roles of precursor structure and disinfection configuration remain unclear. Here, four representative precursors-N-methyl perfluorooctane sulfonamidoacetic acid (N-MeFOSAA), perfluorooctane sulfonamide (PFOSA), 8:2 fluorotelomer sulfonate (8:2 FTS), and 8:2 fluorotelomer phosphate diester (8:2 diPAP)-were compared across individual, simultaneous, and sequential ultraviolet (UV)/chlor(am)ination processes. Individual treatments showed limited precursor transformation, whereas simultaneous UV/disinfectant treatment increased conversion to 16.7-40.8%, with sulfonamide-based precursors exhibiting higher reactivity than fluorotelomer precursors. Fluorine mass balance revealed structure-dependent fluorine fates: sulfonamide precursors were transformed more extensively toward quantified PFAAs, whereas fluorotelomer precursors retained larger estimated unmeasured fluorine fractions. The same transformation behavior was also observed in actual drinking water. Mechanistic analyses integrating non-target high-resolution mass spectrometry (HRMS), reactive-species probe experiments, and density functional theory (DFT) calculations suggested that precursor structure governed reactive-species susceptibility and transformation pathways, with hydroxyl radicals playing a major role in precursor conversion toward PFAAs and chlorine radicals contributing to the initiation of one-electron oxidation steps that enabled subsequent chain shortening. Simultaneous UV/disinfectant treatments also increased PFAA-associated ecological risks and JEG-3 cytotoxicity, and the two endpoints were strongly positively correlated, suggesting that greater PFAA formation during precursor transformation may be accompanied by increased health-relevant toxicity. These findings highlight the importance of precursor structure in determining PFAS transformation and its potential health implications during drinking water disinfection.
Gestational exposure to cadmium (Cd), a widespread environmental toxicant, disrupted placental angiogenesis to induce fetal growth restriction (FGR). This study aimed to clarify the mechanism by which Cd disrupts placental angiogenesis. Human and mouse studies indicated that Cd exposure reduced VEGF-A to disrupt placental angiogenesis. Further data confirmed that gestational Cd exposure promoted estrogen receptor ESR1-specific degradation via ubiquitin-proteasome system (UPS), thereby decreasing placental VEGF-A. Bortezomib, the only clinically approved protease inhibitor, blocked ESR1 degradation to alleviate Cd-impaired placental angiogenesis. Based on mouse and human transcriptomics, WWP2 was identified as an unreported ubiquitin E3 ligase targeting placental ESR1. Specifically, both WWP2 knockdown and its inhibitor NSC2805 treatment consistently reversed environmental Cd-induced placental angiogenesis disorders and FGR. Furthermore, the m6A modification in Wwp2 mRNA was increased in Cd-exposed placentae. METTL3 and ELAVL1 knockdown verified that m6A modification enhanced the stability of Wwp2 mRNA. SAH, an inhibitor for METTL3, not only decreased WWP2 but also alleviated Cd-impaired placental angiogenesis and fetal growth. Based on a human case-control study, m6A-methylated Wwp2 was positively correlated with placental angiogenesis inhibition and all-cause FGR. In conclusion, gestational Cd exposure enhanced m6A modification in Wwp2 mRNA to drive ESR1 degradation, thereby inhibiting placental angiogenesis and fetal growth.
Microplastics (plastic particles ≤5 mm) are a persistent and widespread pollutant in aquatic ecosystems, where they can accumulate in the larvae of aquatic insects inhabiting benthic habitats. Aquatic insects cross aquatic-terrestrial boundaries through metamorphosis, yet few studies have investigated their role in transporting microplastics to terrestrial ecosystems as emergent adults. This study sampled upstream and downstream of eight municipal wastewater treatment plants in the Grand River watershed, Ontario, Canada, in 2022 and 2023 to assess whether these facilities increase microplastics occurrence in aquatic and riparian food webs. Larval and adult caddisflies (Hydropsychidae), mayflies (Heptageniidae), midges (Chironomidae), and riparian spiders (Tetragnathidae) were collected to examine microplastics accumulation, retention through metamorphosis, and cross-ecosystem transfer into riparian spiders. Larval Heptageniidae, adult Chironomidae, and Tetragnathidae exhibited higher microplastic abundances downstream relative to upstream, with concentrations approximately 2.4-, 3.7-, and 2-fold higher, respectively, although the magnitude of differences varied across sites; no significant differences were observed for the other taxa. Organic (cellulose-based) and polyester fibres were the most common, representing ∼25-68% and ∼16-50% of particles across taxa, respectively. Relationships between total microfibre concentration and trophic position (δ15N) were generally weak and site specific, while TTFs >1 were observed between biofilm and larval taxa at most sites but were generally <1 between adult insects and spiders. Together, these findings demonstrate that emergent aquatic insects retain and transfer microplastics across aquatic-terrestrial boundaries to riparian predators but provide limited evidence for consistent trophic magnification across the food web. This research addresses a critical knowledge gap by advancing our understanding of microplastic uptake and movement through nearshore food webs via emergent aquatic insects.
Per- and polyfluoroalkyl substances (PFAS) are widely detected in urban surface waters globally, yet their accumulation in freshwater biota from diffuse pollution remains poorly characterised. Macroinvertebrates are a key component of freshwater food webs and a major dietary pathway for PFAS transfer to higher trophic levels. We quantified PFAS concentrations and compositional profiles in macroinvertebrates collected from 13 urban and 15 non-urban streams in the greater Melbourne region, Australia, all of which lacked known PFAS point sources. Composite macroinvertebrate samples were live-picked and identified to family-level before analysis of 25 PFAS congeners. Overall, 1083 organisms were collected from 57 families. One or more congeners were detected in 89% of samples. Median total PFAS concentrations in urban macroinvertebrates were between 6- and 28.2-times higher than in non-urban macroinvertebrates, and urban organisms had significantly higher PFOS, PFOA, PFDA and PFDoDA concentrations than non-urban organisms. Long-chain congeners dominated tissue concentrations across both land uses, with urban profiles contributing emerging replacement compounds (fluorotelomer sulfonates), whereas non-urban macroinvertebrates exhibited relatively low total PFAS burdens but unexpectedly high concentrations of short-chain PFAS (PFBA). Comparisons with published data show that diffuse urban sources can generate PFAS concentrations in macroinvertebrates approaching those reported at point-source-impacted sites. These findings demonstrate that urban land use strongly influences both the magnitude and composition of PFAS accumulation in freshwater macroinvertebrates and underscore the need for monitoring frameworks that integrate multiple sampling media and consider both legacy and emerging PFAS when assessing ecological risks in freshwater ecosystems.
The mechanisms by which plants tolerate soil contamination have been studied in details in controlled laboratory conditions, but they still remain largely unexplored in natural conditions where mixtures of contaminants are present in soils and their effects might interact with other environmental variables. This is especially true in high-altitude alpine environments, where abiotic stress is naturally heightened, but which so far have received little attention in environmental pollution studies. As we were interested in the tolerance mechanisms at play on very fine spatiotemporal scales for alpine plants growing under multi-stress conditions, we chose Cardamine resedifolia as our biological model. This plant is indeed frequently found in areas contaminated by Trace Metals and Metalloids and Polycyclic Aromatic Hydrocarbons in high elevation. We studied populations from former copper, silver-lead, and coal mines in alpine environments, along with populations growing on nearby reference soils. We measured genetic variability within populations as well as genetic differentiation between them, and tested for local adaptation to soil contamination using reciprocal transplants. Population pairs showing signs of local adaptation were then examined using genome scans to identify genes potentially under selection. We found high levels of genetic differentiation between populations growing on contaminated and reference soils a few dozen meters apart. In most cases local adaptation was detected, especially in former copper mines. Genome scans identified genes involved in metal stress management as potentially being under selection. This study provides evidence for rapid adaptation to human-induced pollution in alpine plants at remarkably small spatial scales. It offers new insights into the short-term ecological and evolutionary consequences of mining activities in alpine ecosystems, particularly in relation to substrate-driven differentiation.
Hydrophobic organic contaminants (HOCs) pose risk to aquatic organisms at high concentrations and have been implicated in the declining health of the endangered fish species, Delta smelt (Hypomesus transpacificus). Legacy and current-use pesticides, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were quantified in a surrogate fish species (Wakasagi; Hypomesus nipponensis), sediments, zooplankton, and suspended solids throughout the Sacramento Deep Water Ship Channel (SDWSC). Forty-four of 63 analytes were detected across the tested media, with legacy pesticides (LPs), PAHs, and PCBs being the most prevalent contaminants measured in Wakasagi. Pyrethroids, a class of current-use insecticides, were rarely detected in Wakasagi tissue. Pattern analysis via cosine similarity showed that contaminant concentrations associated with suspended solids best reflected the concentrations measured within the Wakasagi, suggesting that suspended solids may represent a relevant exposure pathway. While only DDE and DDD concentrations exceeded the threshold effect concentration for sediment (TEC), contaminants associated with suspended solids exceeded most sediment quality guidelines. In addition, PAH concentrations in suspended solids exceeded multiple lesion thresholds for a variety of other fish species. These results suggest potential ecological concern from suspended solid-associated contaminant exposure. Future studies need to be performed to assess the relationship between HOCs associated with suspended solids and their potential harm to pelagic organisms for the purpose of contaminant mitigation in the SDWSC.
Vertical wind shear (VWS) is a key feature of the dynamical structure of the atmospheric boundary layer, yet its association with the vertical distribution of pollution remains insufficiently understood in complex terrain. This study examined VWS structures and their relationships with PM2.5 in Taiyuan Basin using surface observations, wind profiler radar, microwave radiometer, aerosol lidar, radiosonde, unmanned aerial vehicle measurements, and Weather Research and Forecasting model simulations. Unsupervised clustering identified three distinct VWS regimes. Class_1 featured strong near-surface shear dominated by directional changes and was associated with pronounced near-surface PM2.5 accumulation, strong stability, and the shallowest boundary layer. Class_2 exhibited enhanced wind speed shear above 500 m and an elevated PM2.5 maximum near this height. Class_3 showed strong wind speed shear through most of the layer below 2000 m, together with stronger winds and lower PM2.5 concentrations. UAV observations within 0-500 m confirmed distinct PM2.5 profiles among the three regimes. A pollution episode on 17 January 2024 further showed that strong VWS did not necessarily enhance vertical exchange when the shear layer remained above a shallow, stable boundary layer. Its influence became more evident as daytime heating deepened the boundary layer toward the shear layer, whereas evening boundary-layer contraction renewed near-surface accumulation. These results demonstrate that the relationship between VWS and PM2.5 depends on shear height and composition and on the evolving thermal structure of the boundary layer.
BACKGROUND:Every spring (March-April), biomass-burning fires in the Indo-China Peninsula (ICP) send smoke downwind into southern China, coinciding with elevated springtime PM2.5 in Yunnan, Guangxi, and Guangdong. The radiative and ecological effects of this transport are established, but its springtime population-exposure burden remains poorly characterised. OBJECTIVE:To quantify springtime PM2.5 population exposure under WHO and Chinese benchmarks, and attribute the ICP fire contribution with a controlled model experiment. METHODS:Daily PM2.5 from 51 cities was combined with WorldPop population data to compute exposure above the WHO 2021 guideline (24-h, 15 μg/m3) and China's GB 3095-2012 Grade II standard (75 μg/m3) for March-April 2015-2019, and paired GEOS-Chem simulations at 2° × 2.5° with and without ICP fire attributed the fire contribution. RESULTS:At observed PM2.5 concentrations, exposure above the WHO 24-h guideline was near-universal (the population-weighted share of exceedance days reached 78 to 96% every year). Exposure above the higher China Grade II standard was rare in all three provinces, with the population-weighted share of exceedance days spanning 1 to 6% in Yunnan, 1 to 6% in Guangxi, and 0 to 5% in Guangdong; in absolute terms this corresponds to an average daily exposed population of about 6 million across the corridor, under 3% of its residents, with Guangdong's larger population offsetting its lower exceedance fraction. A controlled GEOS-Chem experiment with and without ICP fire attributed 25% (9.6 μg/m3) of Yunnan's springtime PM2.5 to ICP burning, 6% (3.3 μg/m3) in Guangxi and 4% (1.6 μg/m3) in Guangdong, a monotonic west-to-east gradient paralleled by ozone (10%, 5%, 2%). Translating this attribution into exposure, ICP fire carried an estimated average daily population of 2.2-2.6 million above the China PM2.5 standard (36-44% of all above-standard exposure), and about 11 million above the WHO ozone guideline. CONCLUSIONS:The model-attributed ICP-fire contribution is largest in Yunnan and attenuates eastward, while national-standard exceedance remains episodic across the corridor; this pattern supports province-specific, transport-aware air-quality assessment.
Antibiotic contamination in coral reef ecosystems remains poorly understood, particularly regarding its sources, transfer through the food chain, and ecological and dietary risks. This study examined 33 antibiotics in seawater, sediments, suspended particulate matter (SPM), and marine organisms from Qingshui Bay, a tropical coral reef-associated coastal system in southern Hainan Island, China. Twenty-five antibiotics were detected in seawater, while 22 were found in sediments and SPM. Average concentrations were 41.6 ng/L in seawater, 24.2 ng/g dw in sediments, and 38.83 ng/g dw in SPM. Quinolones were the dominant antibiotic class, accounting for 71.2%, 84.1%, and 78.4% of the total in each matrix. Spatial analysis showed slightly higher contamination near the reef and shore than offshore, indicating land-based and aquaculture inputs. Source analysis using principal component analysis (PCA) and positive matrix factorization (PMF) identified aquaculture, livestock, and domestic wastewater as major sources. In marine organisms, 28 antibiotics were detected, averaging 87.6 ng/g dw, with fish and cephalopods exhibiting relatively higher residue levels and bioaccumulation factors than crustaceans and mollusks. Ciprofloxacin and norfloxacin showed strong bioaccumulation potential; six antibiotics demonstrated trophic magnification (trophic magnification factors > 1). Ecological risk assessment indicated low overall risks, with only norfloxacin and sulfadiazine presenting minor concerns in seawater. Dietary risk assessment suggests minimal impact on human health through seafood consumption. This is the first multi-matrix study evaluating antibiotic presence, sources, bioaccumulation, trophic transfer, and risk in a southern Hainan coral reef ecosystem, providing essential baseline data for pollution management.
Early-life exposure to air pollution and green space may influence child growth, but evidence across multiple anthropometric indicators is limited. We examined whether perinatal exposures to particulate matter (PM) and residential green space are associated with longitudinal changes in body mass index (BMI), length, and head circumference (HC). In 119,110 Flemish children, BMI-, length-, and HC-for-age z-scores were derived from well-baby clinic data. Perinatal PM10 and PM2.5 concentrations were estimated using the RIO detrended-kriging interpolation model. Municipal green space was categorized into low, high, and total vegetation. Mixed-effects models incorporating a 5-degree-of-freedom natural cubic spline for child age, exposure-by-age spline interaction terms, and child-level random intercepts and age slopes were used to assess associations per interquartile-range (IQR) contrast in exposure, adjusting for key covariates and co-exposures. Associations varied nonlinearly across child age and growth outcome. At 12 months, an IQR increases in PM10 or PM2.5 concentration were associated with lower HC-for-age z-scores (PM10: B = -0.0499; 95% CI: -0.0606; -0.0393; PM2.5: B = -0.0645; 95% CI: -0.0771; -0.0518), and inverse associations were observed between 6 and 24 months. Associations of PM with BMI-for-age and length-for-age changed direction across age. Total and high green-space exposures were associated with higher BMI-for-age and length-for-age at several ages, whereas associations with HC were inconsistent across green-space measures and ages. Low green-space exposure was associated with lower HC-for-age and length-for-age at several ages. Estimates were small, and urbanicity did not consistently modify associations. Most nominally significant associations remained significant after false-discovery-rate correction; exceptions were PM2.5 exposure at 2 months and high and total green-space exposure at 12 months in relation to length-for-age. Perinatal air pollution and green space exposures showed small, nonuniform associations with early childhood growth that varied across child age and anthropometric outcomes.
Declining PM2.5 mass concentrations do not necessarily ensure proportional mitigation of hazardous particle-bound components. We investigated 16 priority PM2.5-bound PAHs in Kunming, China, and compared their concentrations, BaPeq burden, particle-normalized toxicity-equivalent intensity, source-related patterns, and inhalation cancer risks between lower- and higher-PM2.5 stages. From the higher- to lower-PM2.5 stage, PM2.5, ΣPAHs, and BaPeq decreased by 32.7%, 27.4%, and 31.4%, respectively. Covariate-adjusted models confirmed significant reductions in ΣPAHs and BaPeq of 28.8% and 33.5%, whereas BaPeq/PM2.5, which represents the BaP-equivalent burden of the measured particle-bound PAHs per unit mass of PM2.5, showed no significant decrease (-7.6%, p = 0.274), and BaPeq/ΣPAHs decreased only modestly (-6.5%, p = 0.026). The contribution of 4-6-ring PAHs remained above 81%, while BaP and dibenzo[a,h]anthracene together accounted for more than 82% of BaPeq in both stages. PAH-PMF results, interpreted conservatively as source-related chemical patterns, indicated persistent combustion-related PAH signatures, while RF-SHAP analysis identified carbonaceous and selected metal-related components as the leading predictors of absolute BaPeq. Despite the lower particle loading, 40.3% of simulated adult ILCR values exceeded 10-6. These results demonstrate that reductions in particle mass and absolute hazardous-component burden may coexist with persistent toxicity-equivalent intensity per unit particle mass. Joint evaluation of PM2.5, BaPeq, and BaPeq/PM2.5 can therefore provide a practical framework for toxicity-oriented management of hazardous particulate components.
Antimicrobial resistance (AMR) is a growing global health threat, yet the extent to which environmental resistomes reflect human disease burden remains unclear. In this study, we provide the first attempt to bridge freshwater resistomes with human disease burden using machine learning models, with a focus on identifying environmental signatures associated with drug-resistant tuberculosis (DR-TB) burden. By analyzing 1280 freshwater metagenomes from 45 countries, we characterized the compositional distribution of the resistomes and further developed an integrated environmental AMR Risk Score. Integrating the AMR Risk Score with socio-economic variables provided complementary information associated with variation in multidrug-resistant tuberculosis burden beyond socio-economic factors alone. In complementary income-stratified analyses, feature selection identified recurrent environmental signatures associated with different drug-resistant tuberculosis subgroups. These findings indicate that freshwater resistome characteristics contain geographically structured information associated with DR-TB burden within the sampled datasets and support the potential value of freshwater metagenomic surveillance for characterizing environmental AMR patterns.
The overuse of the broad-spectrum antibiotic florfenicol (FF) and its residues in coastal benthic environments pose toxicological risks to marine crustaceans. As an economically important benthic species, the mud crab is vulnerable to FF pollution stress, yet its toxicological responses and underlying mechanisms remain unclear. Therefore, this study investigated the physiological, biochemical, and transcriptomic responses of the mud crab hepatopancreas following FF exposure. Healthy mud crabs were assigned to one control group and three FF exposure groups (5, 50, and 500 μg/L) and exposed for 10 days. The results demonstrated that FF accumulated in the hepatopancreas in a concentration-dependent manner, significantly reduced the weight gain rate and hepatosomatic index, and induced marked histopathological alterations. Furthermore, FF stress significantly elevated MDA content, disrupted the homeostasis of antioxidant and detoxification systems (including SOD, CAT, GST, GSH, and T-AOC), and induced oxidative stress. Transcriptomic analysis and gene set enrichment analysis (GSEA) showed that FF impaired lipid metabolism mainly by suppressing PPAR signaling and inhibiting fatty acid synthesis and degradation. FF exposure was also associated with persistent downregulation of melanogenesis-related pathways, suggesting potential impairment of innate immune-related functions. These alterations likely contributed to growth inhibition in mud crabs under FF stress. Weighted gene co-expression network analysis (WGCNA) combined with protein-protein interaction (PPI) analysis identified HSPA8 and phc-2 as candidate hub genes potentially associated with compensatory detoxification and epigenetic growth restriction, respectively. These findings elucidate the molecular regulatory networks underlying FF-induced hepatopancreatic damage, providing useful evidence for the environmental risk assessment and toxicological evaluation of antibiotic residues in mud crab aquaculture.
Polystyrene microplastics (PS-MPs, <5 mm) are ubiquitous contaminants that accumulate in the liver through dietary exposure, leading to hepatocellular damage. However, the dynamic changes in glutathione (GSH) under PS-MPs exposure and its underlying mechanisms in liver injury remain poorly understood. In this study, we harnessed the tunable excited-state intramolecular proton transfer (ESIPT) properties of natural flavonols to develop a GSH-activated flavonol probe, BQ-N. Structurally, BQ-N incorporates a 2,4-dinitrobenzenesulfonyl (DNBS) moiety as a fluorescence-quenching group, enabling selective fluorescence restoration through a thiol-mediated nucleophilic substitution reaction. The BQ-N probe was successfully employed for real-time monitoring of GSH in living cells and in a mouse model of liver injury induced by PS-MPs exposure. Further mechanistic studies revealed that PS-MPs exposure downregulates the expression of Glutathione Peroxidase 4 (GPX4) and ferritin, while upregulating the expression of oxidative stress-related proteins heme oxygenase-1 (HO-1) and quinone oxidoreductase 1 (NQO1). These findings suggest that PS-MPs may mediate liver injury by activating the ferroptosis pathway through interference with GSH metabolism and redox balance. In summary, the BQ-N probe enables real-time visual monitoring of GSH via fluorescence imaging at both the cellular level and in isolated animal organs and provides an effective early detection tool for PS-MP-induced liver injury. Furthermore, it reveals partial molecular mechanisms of microplastic hepatotoxicity from the perspective of the GSH-ferroptosis axis, offering new insights for integrating environmental pollutant health risk assessment with molecular imaging technology.
The increasing accumulation of microplastics (MPs) in terrestrial environments has intensified the need for reliable methods to detect and quantify MPs in complex soil matrices. This study aimed to establish and optimize a protocol for quantifying MPs in soil. Important steps include soil organic matter (SOM) digestion, MPs extraction, Nile red staining, fluorescence microscopy detection, and MPs counting after image processing, in which the efficiencies of SOM digestion and MPs extraction play the crucial roles and were systematically optimized. Digestion reagents including H2O2, Fenton's reagent, and HNO3 were evaluated for their abilities to remove SOM that can induce background fluorescence interfering with MPs quantification. Among the tested reagents, HNO3 achieved the highest background fluorescence removal efficiency (89% in loam and 82% in clay) without causing significant damage to polypropylene (PP) and polyvinyl chloride (PVC) MPs. CaCl2 (1.4 g/cm3) and ZnCl2 (1.6 g/cm3) showed similar efficiencies for MPs extraction but CaCl2, which yielded recoveries of 78-80% for PP and 61-70% for PVC in tested soils, was selected over ZnCl2 due to its lower environmental toxicity. The established protocol was applied for soil samples collected from three sites designated for different land uses. The highest MPs concentration was found in samples collected from a farmland (1.04 × 105 particles/kg), followed by a landfill site (7.10 × 104 particles/kg) and a park (4.00 × 104 particles/kg), with MPs < 100 μm being the dominant size in all samples. Overall, the established protocol shows potential for application in assessing MPs contamination in terrestrial environments.
Methoxychlor (MXC) is a persistent organochlorine pesticide that may enter poultry production through contaminated feed. However, the effects of prolonged low-dose dietary exposure in avian species remain poorly characterized. In this study, male broilers were fed diets containing 0, 2, 10, 50, or 200 μg/kg MXC for 42 days. Growth performance, hematological and serum biochemical indices, organ indices, histopathology, and serum inflammatory and oxidative-stress markers were evaluated; network toxicology and molecular docking were used as exploratory computational analyses. MXC treatment produced stage-specific growth effects, with reduced average daily gain during days 22-42 in the 2, 10, and 200 μg/kg groups. At day 42, kidney indices were increased in all MXC-treated groups, and histological examination revealed treatment-related lesions in the liver and kidneys. Serum cytokine and redox markers also changed in a time- and treatment-dependent manner, without a clear monotonic concentration-response pattern. Network analysis based primarily on human databases predicted 239 overlapping MXC-liver-injury candidate targets and prioritized 44 candidate hub targets, including AKT1, SRC, and CASP3, with enrichment of NF-κB- and PI3K-Akt-related pathways. Docking analyses predicted favorable modeled interactions between MXC and six selected candidate hub proteins. Overall, subchronic dietary MXC exposure at low concentrations adversely affected broiler growth and produced hepatic and renal injury accompanied by systemic inflammatory and oxidative perturbations. The computational results are hypothesis-generating and require direct biological validation.
