Vehicular emissions are a major urban source of nitrated polycyclic aromatic hydrocarbons (NPAHs), yet the impact of recent emission standard upgrades on NPAH mass and toxicity remains unclear. We conducted two comprehensive tunnel campaigns in Guangzhou (2014 and 2019) to quantify changes in PM-bound parent PAHs and NPAHs from real-world vehicle fleets. Fleet-average mass-based emission factors (EFs) for total PAHs and total NPAHs decreased by 74.8 % (45.22-11.39 μg km veh) and 57.8 % (7.06-2.98 μg km veh), respectively. In contrast, the total carcinogenic potency of the NPAH mixture, expressed as benzo[a]pyrene toxic equivalents (TEQ), increased by 28.3 % (2.69-3.45 μg km veh). This divergence reflects a compositional shift in the traffic fleet: in 2019 diesel vehicles constituted only 3.3 % of traffic but accounted for 91.0 % of NPAH emissions with enrichment in high-potency congeners such as dinitropyrenes. These real-world measurements demonstrate that mass-only metrics for regulated (PAHs) and unregulated (NPAHs) emissions can be misleading, and highlight the need for toxicity-weighted indicators and diesel-targeted control strategies to manage NPAH hazards in modern fleets.

Coastal cities experience persistent air pollution episodes driven by mesoscale circulation such as land-sea breezes, which can recirculate pollutants and intensify near-surface concentrations. This study quantitatively evaluated the impact of pollutant recirculation influenced by land-sea breeze circulation and ship emissions on high PM episodes in Busan, South Korea. The Recirculation Index (RI) from 2016 to 2024 was analyzed, and April had the highest values, indicating a high potential for recirculation-related air pollution. April 2019 was selected, when recirculation events coincided with high PM concentrations. Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) simulations for two high pollution cases (April 7 and 21) revealed that PM was recirculated between land and sea by diurnal land-sea breeze circulation, sustaining high concentrations in both cases. However, differences in boundary layer development, sea breeze direction, and vertical mixing intensity influenced by synoptic conditions and Busan's coastal geography with southern and eastern coastlines altered the transport pathways and spatial patterns of elevated PM. Integrated Process Rate (IPR) analysis showed that a deeper boundary layer (April 7) enhanced vertical mixing, whereas a shallower boundary layer (April 21) trapped pollutants near the surface, prolonging high concentrations. Source apportionment indicated that ship emissions contributed 0.2-14 % to PM, and recirculation enhanced PM and sulfate concentrations by 1.4 and 3.6 %, respectively. The RI is practical for evaluating the recirculation potential. These findings highlight the role of land-sea breeze recirculation in amplifying ship emissions and underscore the need for targeted coastal emission-control strategies.

Per- and polyfluoroalkyl substances (PFAS) are a globally pervasive class of persistent and potentially toxic contaminants. This study investigates the prevalence, transport, and partitioning behavior of 19 PFAS within Georgica Pond (NY, USA), a shallow, temporarily-open estuary fed by groundwater historically impacted by aqueous film forming foam (AFFF). PFAS concentrations were measured in groundwater, groundwater seepage, and sediments, and surface waters to evaluate the abundance, distribution, and the influence of environmental factors on PFAS fate and transport. Perfluorooctane sulfonate (PFOS; 32 ± 13 ng L) and perfluorohexane sulfonate (PFHxS; 30 ± 17 ng L) were the dominant PFAS detected in groundwater, while short-chain perfluoroalkyl acids (PFAAs) perfluorobutane sulfonate (PFBS) (9.8 ± 6.9 ng L) and perfluorohexanoic acid (PFHxA) (10.2 ± 5.7 ng L) were most abundant compounds in Georgica Pond surface waters. In sediments, PFBS (1.5 ± 0.91 μg kg1) was most abundant in tributaries, while 6:2 fluorotelomer sulfonic acid (6:2 FTS) (1.5 ± 0.91 μg kg d.w) was dominant in estuarine sediments. ∑PFAS and individual PFAS concentrations in surface waters were significantly (p<0.001) and inversely correlated with salinity, suggesting dilution and/or enhanced sorption of PFAS in marine waters. Additionally, ∑PFAS as well as PFBS and PFHxS concentrations in sediment were strongly and significantly correlated with sediment organic matter content, indicating preferential accumulation in organic-rich substrates. These findings highlight the combined influence of salinity dynamics and in situ physical processes governing PFAS distribution and partitioning. Collectively, these results underscore the complex transformations of PFAS as they traverse the groundwater-to-sediment-to estuarine continuum that have direct implications for contaminant persistence and bioavailability.

Wetlands acting as pollutant sinks make them a hotspot for microplastics (MPs) pollution, yet source-driven MPs accumulation assessments are limited, representing a gap hindering targeted mitigation strategies, particularly in biodiverse regions. To address this, the present study combined two years pre- and post-monsoon MPs abundances with PCA-APCS-MLR to determine polymer-specific MPs sources in Deeporbeel, a Ramsar site in Northeast India. Water and sediment samples (6 sites × 3 replicates) were collected during both seasons over two years, followed by NOAA-standard protocols and μ-Raman characterization. Water MPs abundance during the pre-monsoon season peaked at sites S2 (0.84 ± 0.16 particles per L) and S6 (1.44 ± 0 particles per L), while post-monsoon at site S6 (1.21 ± 0.02 and 2.12 ± 0.10 particles per L) across both years. Sediment MPs were consistently highest at site S1 (11.22 ± 0.42 and 9.44 ± 1.96 particles per 100 g) during both seasons. Fibers remained >50 % in both media, with PVC (31 %) dominant in sediments and ABS (29 %) in water. PCA-APCS-MLR explained 91.6 % of the total variance in water (meanR=0.92) and 98.29 % in sediment samples (meanR=0.98), identifying four and three potential sources, respectively. Among the identified polymers, PVC (59.10 %) dominated water, and ABS (33.1 %) dominated sediment samples. Water MPs linked to industrial and commercial, packaging, household, medical, and automobile-vehicle inputs, whereas sediments reflected site-specific contributions. The identified sources showed the Deeporbeel role as a continuous MPs sink. This polymer-based source apportionment allowed feasible insights for targeted mitigation, enabling management of potential sources and designing seasonal monitoring and control strategies.

The surge demand for disposable plastics items around the world not only led to a sharp consumption in natural and petroleum resources but laid a heavy burden on environmental waste management, due to their inevitable fragmentation and potentially as a source of microplastics (MPs). Regrettably, their environmental behavior still lack sufficient understanding. This study aims to investigate the ultraviolet (UV) aging of disposable face towels, an emerging kind of disposable plastics items, made of regenerated cellulose (RC) or polyethylene terephthalate (PET), and its vector effect in aquatic environment. The variation and influences of surface physicochemical characteristics, including its surface charge and hydrophilic properties, type of dye pollutants and environmental factors, especially the salinity, on their interactions were comparatively characterized or explored. The results indicated that hydrogen bonding primarily governed the interactions of RC-MPs and dyes with electrostatic interaction involving, while the interactions of PET-MPs and dyes were predominantly driven by electrostatic attraction. Environmental factor analysis revealed that disposable face towels tends to associate readily with various pollutants in aquatic environments, particularly in marine ecosystems. This research provides important insights into the environmental behavior and fate of MPs released from disposable face towels.

Groundwater is a vital resource in water-scarce South Africa, but faces significant anthropogenic pollution threats. Per- and polyfluoroalkyl substances (PFAS), widely used chemicals with high environmental persistence, have been detected in South African surface and groundwater, often exceeding drinking water limits. Our study assessed groundwater vulnerability to PFAS pollution across South Africa using a modified DRASTIC method, termed DRASTIL. The DRASTIC method, which considers hydrogeological factors like Depth to groundwater (D), Recharge (R), Aquifer media (A), Soil type (S), Topography (T), and Impact on vadose zone (I), was adapted by removing a redundant parameter (hydraulic Conductivity, C) and adding Land use (L). Land use was incorporated due to its critical role in providing spatial context for expected PFAS pollution sources. The methodology involved a weighted overlay of these seven parameters within a Geographic Information System (GIS), utilizing existing hydrogeological data and land use data linked to potential PFAS sources. Calibration was performed using existing PFAS measurements in surface water and boreholes. Results indicate that the Western Cape, particularly Cape Town, is highly vulnerable due to a combination of urban areas, agriculture, high recharge, shallow groundwater, and permeable geological features. Similar high vulnerability was observed in parts of Free State, North West, and Gauteng, influenced by mining, agriculture, urban areas, and karst aquifer systems. Overall, over 36% of South Africa's area is classified as moderately to extremely high-risk for PFAS groundwater pollution. Gauteng, despite being the smallest province, has over 25% of the country's population and over 60% of its area in the high-risk category. The Western Cape and North West also show high proportions of vulnerable areas (50.4% and 49.6%, respectively). These findings highlight the urgent need for targeted management strategies and monitoring of PFAS concentrations in identified high-risk areas to safeguard South Africa's crucial groundwater resources.

Nanoplastics (NPs) are widespread in aquatic environments and pose potential risks to aquatic organisms. In this study, a novel fin-derived cell line from sea perch (LJFin) has been established to evaluate the size-dependent toxicity of polystyrene nanoplastics (PS-NPs) and the potential mechanism underlying their actions on sea perch iridovirus (SPIV) infection. The cell viability assay showed that the particle size, concentration of PS-NPs, and the exposure time directly determined their cytotoxicity on LJFin cells. Exposure to 80 nm PS-NPs (PS-80) at 100 μg/mL for 96 h significantly reduced cell viability, whereas 500 nm PS-NPs (PS-500) were nontoxic to LJFin cells. Moreover, PS-NPs were internalized into LJFin cells in a time-dependent manner. PS-80 entered the cytoplasm more efficiently, but the majority of PS-500 were intercepted on the membrane. Both PS-80 and PS-500 were capable of inducing inflammatory response and antioxidant damage in LJFin cells. In addition, PS-NPs exposure increased SPIV replication, even promoting viral entry at the early stage of SPIV infection. Furthermore, sucrose treatment not only significantly inhibited PS-NPs internalization but also reduced the pro-viral effect of PS-NPs during SPIV infection. In contrast, methyl-β-cyclodextrin and ethyl-isopropyl amiloride treatment exhibited no regulatory effects, suggesting that PS-NPs internalization and promoted SPIV replication via the clathrin-mediated endocytosis in vitro. Overall, our findings offer new insights into the pro-viral actions of PS-NPs on fish iridovirus infection in vitro, which highlights a potential threat of NPs to aquatic viral diseases.

The increasing emerging contaminants (ECs) pose significant challenges to non-targeted screening (NTS) and annotation. Machine learning-based retention time (RT) prediction models offer a promising approach to narrow candidate compounds and enhancing identification accuracy. However, existing studies rely on a single machine learning algorithm, which is susceptible to overfitting or underfitting on particular datasets and may yield substantial prediction bias. To address these limitations and improve both predictive performance and generalization capability, we developed an ensemble modeling framework that integrated predictions from multiple base models (i.e., eXtreme Gradient Boosting, Light Gradient Boosting Machine, Random Forest, and Support Vector Regression) through a weighted fusion strategy. Based on our self-built database of 362 ECs, we used molecular descriptors and fingerprints to construct this ensemble model framework to predict RT of ECs. The optimized ensemble model significantly outperformed individual models (R = 0.96 vs. R = 0.57-0.87). Further feature optimization reduced training and prediction times by 72.8% and 96.2%, respectively. Applied to screen for ECs in sewage and soil samples, the ensemble model enabled high-confidence classification (ΔRT < 1.5 min) for 101 S2 level ECs, reducing EC candidates by 57%. Meanwhile, bisphenol A (BPA) and tris(2-chloroethyl) phosphate (TCEP) with higher confidence and larger relative peak areas were selected for quantitative verification. The results showed that both were detected in sewage and soil samples (BPA: 175.5 μg/kg; TCEP: 788-3957 ng/L), further verifying the application ability of the model. Ecological risk assessment via toxicological priority index identified personal care products and pharmaceuticals as primarily high-risk ECs, with fipronil, ensulizole, lidocaine, amantadine, and sulpiride posing greatest risks. This ensemble framework provided precise RT prediction for NTS, improving EC detection efficiency and supporting risk management.

Abnormal levels of serum total bile acid (TBA) show an association with various adverse pregnancy outcomes. Bisphenols may disrupt the homeostasis of serum TBA during pregnancy, which potentially affects the health of pregnant women. We investigated 1,317 pregnant women from the Guangxi Zhuang Birth Cohort. Various single-pollutant and multipollutant statistical models were performed to assess the effects of bisphenol exposure during early pregnancy on TBA in different trimesters. In generalized linear model, bisphenol A (BPA) levels were negatively correlated with TBA levels in the first (β = -0.084; 95 %CI: 0.145, -0.022) and second trimesters (β = -0.122; 95 % CI: 0.181, -0.063). Similarly, elevated tetrabromobisphenol A (TBBPA) concentrations displayed a correlation with decreased TBA concentrations in the second trimester (β = -0.093; 95 % Cl: 0.174, -0.012). Quantile g-computation indicated the relation of increased bisphenol mixtures to decreased in TBA levels in the second trimester (β = -0.202; 95 % CI: 0.338, -0.066). In Bayesian Kernel Machine Regression, an inverse association was found between bisphenol mixtures and TBA levels in the first and second trimesters, whereas BPA possible served as a major contributor. These above findings were more significant in obese pregnant women, those carrying female fetuses, and in low-temperature (<20 °C) environments. The results suggest that early pregnancy exposure to single and mixed bisphenols may reduce serum TBA levels during pregnancy, and this phenomenon may be primarily driven by BPA. Interactions effects of prepregnancy BMI, fetal sex, and ambient temperature on the relationship was observed between bisphenol exposure and TBA levels.

This study in the Bouregreg estuary examines the accumulation and seasonal variation of potentially toxic elements (PTEs) in three native halophytes: Halimione portulacoides, Salicornia perennis, and Spartina maritima. PTEs concentrations of cadmium (Cd), chromium (Cr), copper (Cu), zinc (Zn), and vanadium (V), remained below known phytotoxic thresholds, showing high tolerance across all species. S. maritima showed the highest accumulation, likely due to habitat-related factors such as submersion duration and sediment conditions. Compared to a construction-period data, current findings show increased Cr and decreased Zn and Cu levels, especially in H. portulacoides, reflecting post-construction environmental changes. All species exhibited root-dominant metal accumulation. Bioaccumulation indices (bioaccumulation coefficient (BAC), bioconcentration factor (BCF), and translocation factor (TF)) confirmed species- and metal-specific strategies. For cadmium, S. maritima showed high accumulation (BCF >40, BAC >30), while S. perennis reached BAC values up to 26.5 with site-dependent uptake. Chromium was effectively translocated by S. maritima (TF > 1, shoot-soil r ≈ 0.98) and H. portulacoides (stem-soil r = 0.99), while S. perennis showed limited uptake despite strong correlations. Copper was excluded by S. maritima, but actively translocated by H. portulacoides and S. perennis (TF > 1). Zinc showed weak accumulation across species (BAC <1); S. maritima had strong shoot-soil correlations, while others showed efficient translocation but poor soil correlation. Vanadium was consistently translocated (TF > 1) with positive shoot-soil correlations across all species. Cadmium showed weak correlations with other metals, suggesting independent, possibly anthropogenic sources. In contrast, Zn, Cu, Cr, and V co-varied with species-specific patterns and peaked in summer, while Cd peaked in autumn, likely from senescence and site conditions. Overall, these findings provide new field-based evidence of halophyte tolerance and adaptive strategies, underscoring their dual-ecological role as bioindicators of contamination and as promising agents for phytoremediation in the Bouregreg estuary under ongoing urban pressures.

Continuous exposure to products containing phthalate acid esters (PAEs) has generated concerns regarding their impact on human health. This study was aimed at evaluating occupational exposure to PAEs metabolites among 90 municipal waste collection workers compared to 90 staff involved in janitorial duties across academic, administrative, and institutional areas (as a control group). Blood serum samples were analyzed to quantify multiple PAEs metabolites, alongside assessments of hematological, biochemical, inflammatory, oxidative stress, liver, thyroid, and kidney function biomarkers. Results showed significantly higher PAEs metabolite levels in exposed workers (total PAEs mean ± standard deviation: 25.66 ± 12.81 μg/L vs. 15.03 ± 5.14 μg/L, p < 0.001), accompanied by alterations in blood indices-including decreased white blood cells (WBC) and hemoglobin (HB), elevated red blood cells (RBC) and eosinophils-and elevated liver enzymes, thyroid hormones, and inflammatory markers such as the inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). The findings suggest that PAEs' metabolite levels are largely unaffected by demographic and lifestyle factors, highlighting occupational exposure as the predominant source in this group. Network analysis revealed that occupational exposure to PAEs, including Mono(2-ethylhexyl) phthalate (MEHP), in municipal sanitation workers is associated with significant alterations in neutrophils, 8-hydroxy-2'-deoxyguanosine, (OHdG8), thyroid parameters (triiodothyronine (T3) and thyroxine (T4), prothrombin time )PT(), and hematological factors (albumin, mean corpuscular hemoglobin concentration )MCHC(), and partial thromboplastin time (PTT)). These findings highlight the impact of occupational PAEs exposure on multiple physiological systems and underscore the need for preventive measures and continuous health monitoring in this population.

This study investigated microplastic (MP) pollution in the Pearl River Estuary (PRE), focusing on the effects of tidal intensity and suspended sediment concentrations (SSC) on their distribution. Tidal intensity, a key hydrodynamic driver, influences MP transport by altering water flow and sediment resuspension in estuaries, shaping pollution patterns. Surface water samples were collected from 16 sites during spring and neap tides, revealing an average MP abundance of 10.48 ± 3.60 items/L during spring tides (average SSC: 20.00 ± 4.74 mg/L), significantly higher than 7.58 ± 3.78 items/L during neap tides (average SSC: 19.12 ± 3.90 mg/L, p = 0.005). Fibers were the dominant shape (54.2%), while small MPs (<1 mm) accounted for 88.7% of the total during spring tides and 91.2% during neap tides, indicating extensive weathering and hydrodynamic sorting within the estuary. Stronger tidal forces during spring tides enhanced MP transport via sediment resuspension, while neap tides promoted localized accumulation. A significant positive Spearman correlation between SSC and MP abundance was observed during spring tides (R = 0.4525, p = 0.004), but not during neap tides. By integrating remote sensing-derived SSC data with field observations, this study demonstrates the potential for satellite-based monitoring of MP distribution in dynamic estuarine systems. These findings highlighted the critical role of tidal dynamics in MP distribution and emphasize the need for targeted pollution management, including reducing upstream plastic inputs, in estuarine systems. This study provides valuable insights into MP behavior under varying hydrodynamic conditions, offering an innovative foundation for improved monitoring and mitigation strategies in coastal environments.

Environmental contaminants, particularly persistent organic pollutants (POPs) and mercury, pose significant threats to wildlife health, with complex interactions between contaminants and biological processes that are challenging to assess in field studies. This research investigates the oxylipin metabolome in liver samples from polar bears (Ursus maritimus) in two geographically distinct subpopulations from Western Hudson Bay (WHB) and Baffin Bay (BB), Canada, with the aim of elucidating the impact of environmental contaminants on metabolic and inflammatory pathways. Oxylipins, bioactive lipid metabolites derived from polyunsaturated fatty acids, regulate critical biological processes such as inflammation and vascular tone. We identified significant differences in oxylipin levels between the two subpopulations, with WHB bears showing higher concentrations of several key metabolites, including Prostaglandin E (PGE2) and 5-iPF2a-VI, an isoprostane, both associated with inflammation and oxidative stress. Contaminant analysis revealed elevated levels of specific POPs, including polybrominated diphenyl ether (PBDEs), in WHB polar bears. These results suggest a potential link between contaminant exposure and altered oxylipin metabolism, which may contribute to liver dysfunction and inflammation. Multivariate analysis also revealed correlations between contaminants and metabolic pathways related to liver disease, including arginine biosynthesis and alanine, aspartate and glutamate metabolism. Our findings underscore the importance of considering the interplay between environmental contaminants and lipid signaling in wildlife health, particularly in the context of Arctic ecosystems, and highlight the need for further research to explore the long-term impacts of these exposures on polar bear populations and other wildlife species in the Arctic.

Nitryl chloride (ClNO) is widely recognized as a nocturnally formed species that influences next-day air quality through early-morning photolysis. However, its formation mechanisms and diurnal behavior remain poorly constrained, particularly its persistence beyond the morning. Here, we present the first wintertime observations of ClNO in South Korea, revealing its sustained presence and photochemical impacts under urban conditions. Observed ClNO concentration averaged 208 pptv in the morning and 27 pptv in the afternoon, with a campaign maximum of 2.25 ppbv (1-min resolution). These patterns, along with supporting chemical and meteorological parameters, suggest that elevated morning ClNO resulted from reduced photolytic loss under weak solar radiation and continued NO uptake. In contrast, observational evidence indicates a possible linkage between particulate NO photolysis and additional afternoon formation, particularly in aerosols enriched with anthropogenic chloride. This persistent ClNO shifted the diurnal peak of Cl radical production to late morning, with ∼33 % of daily production occurring in the afternoon-surpassing the morning contribution (22 %). Observation-constrained box modeling further showed that ClNO-driven ozone (O) production was comparable in both morning and afternoon periods, each contributing ∼38 % to the total ClNO-related O enhancement. This demonstrates that substantial Cl-initiated oxidation can persist well into the afternoon, even under moderate NO levels (6.4 ± 6.9 μg/m, average ± 1σ). These findings underscore the importance of considering ClNO-driven oxidation throughout the day and highlight the need for further observations across seasons and urban environments to better constrain its atmospheric role.

Arsenic (As) and uranium (U) are toxic trace elements and can contaminate groundwater. Elevated As and U concentrations exceeding the WHO drinking water guideline values were found within the capillary fringe and shallow groundwater at an agricultural site in the Hessian Ried, Germany. The elevated U concentrations can be attributed to the nitrate-triggered roll-front release of geogenic U in the redoxcline, while the elevated As concentrations are associated with the reductive dissolution of Fe-Mn oxyhydroxides at greater depth. To investigate the release of these elements and specifically the role of nitrate, we conducted a 90-day incubation experiment of the alluvial sediments in an inert atmosphere (N) glovebox. Mesocosms amended with nitrate (220 mg L) and without nitrate were incubated in triplicates. In the control mesocosms, we observed a progressive decline in Eh, accompanied by the release of Mn and Fe due to reductive dissolution of (oxyhydr)oxides, which led to a release of As. In contrast, in the nitrate-amended mesocosms, heterotrophic denitrification caused (sub)oxic conditions, which inhibited the reductive dissolution of (oxyhydr)oxides, but led to the oxidative release of U. Sequential and single extractions showed that the geochemical fractions of U did not change and that about 93 % occurred as reduced U(IV) before and after the experiment. Our findings suggest that agricultural inputs of nitrate can cause the release of geogenic U, while simultaneously reducing the reductive release of As.

Hypertensive disorders of pregnancy (HDP) are a leading cause of maternal and infant mortality and morbidity worldwide. This prospective cohort study investigated the association of racial and ethnic disparities in HDP and explored the potential mediation effect of environmental chemical exposures on excess HDP risk among non-Hispanic Black pregnant people. A total of 3,279 pregnant people were included from 11 cohorts across the United States in the Environmental influences on Child Health Outcomes (ECHO) Program. We analyzed 20 environmental chemicals detected in over 70 % of biospecimens collected during pregnancy. Among Hispanic, non-Hispanic White, and non-Hispanic Black participants, 11.8 %, 10.8 %, and 16.6 % were diagnosed with HDP, respectively. Compared with non-Hispanic White participants, non-Hispanic Black participants had a higher risk of HDP (aRR = 1.48; 95 % CI 1.13-1.94) and higher levels of traditional phthalate metabolites, but lower levels of phthalate alternative metabolites and perfluorooctanoic acid. Hispanic participants had a lower risk of gestational hypertension (aRR = 0.62; 95 % CI 0.40-0.98) and lower levels of perfluoroalkyl substances than non-Hispanic White participants. Critically, despite these race/ethnicity-specific exposure patterns, individual chemical exposures did not mediate the association between racial/ethnic group and HDP. These findings highlight the need to investigate cumulative chemical mixtures and non-chemical environmental and social determinants as potential drivers of HDP disparities.

Skeletal fluorosis has a complex pathogenic mechanism and diverse phenotypes, which mainly manifest as osteosclerosis, osteoporosis, and osteomalacia. Differences in nutrient levels exert a vital effect on skeletal fluorosis development. Aberrant DNA methylation modification is related to skeletal fluorosis pathogenesis and progression, and there are nutritional factors significantly impacting DNA methylation. Methionine, as the essential amino acid, is the only direct precursor of methyl donor S-adenosylmethionine. Based on our previous research, the present work first explored the effect of methionine on bone turnover abnormalities in rats with different types of skeletal fluorosis. Our results showed that osteoclast-mediated bone resorption had a predominant role in osteoporotic/osteomalacic skeletal fluorosis, while methionine supplementation primarily attenuated this process. Then, we examined the methylation levels of Siglec-15 in fluoride-exposed osteoblasts and osteoclasts under different nutritional conditions, and explored the regulatory role of methionine in Siglec-15 methylation. The results indicated that the Siglec-15 showed aberrant methylation and expression in fluoride-exposed osteoblasts and osteoclasts under different nutritional conditions. Notably, SIGLEC-15 up-regulation specifically promoted fluoride-exposed osteoclasts differentiation through the TYROBP-SYK pathway, while it was not associated with osteoblast differentiation. Under low nutritional conditions, methionine supplementation inhibited fluoride-exposed osteoclast differentiation by modulating Siglec-15 methylation. Finally, we explored the potential mechanism underlying the effect of methionine on Siglec-15 methylation. From our findings, the up-regulation of TET2 promoted Siglec-15 hypomethylation and induced its high expression, therefore increasing the fluoride-exposed osteoclast differentiation under different nutritional conditions. Under low nutritional conditions, methionine deficiency reduced the SAM/SAH ratio and activated TET2 to induce Siglec-15 hypomethylation in fluoride-exposed osteoclasts. Our findings elucidated the logical link between methionine, DNA methylation, osteoclast differentiation and different skeletal fluorosis types.

Methylmercury (MeHg) exposure is a global environmental concern. Rice-derived MeHg exposure poses a potential neurodevelopmental risk in inland populations with low fish intake, yet epidemiological evidence remains scarce. This representative mother-infant cohort study was conducted in a mercury mining area in China, involving 420 mother-infant pairs, of which 206 were from mercury-exposed regions and 214 were from control regions. It was first found that the median total mercury and methylmercury levels in rice from mercury-exposed areas (11.19 ng/g and 5.07 ng/g) were significantly higher than those in control areas (3.34 ng/g and 1.09 ng/g). And the exposure levels of total mercury and MeHg in environmental media (rice) and population samples (placenta and umbilical cord blood) were positively correlated with the incidence of neurobehavioral developmental impairment (NBDI) in newborns. Subsequently, using a multistage logistic regression model, a significant association was demonstrated between placental MeHg exposure and NBDI (OR = 1.23, 95% CI 1.02-1.49). Restricted cubic spline models further supported this positive linear dose-response relationship. Additionally, NBDI risk prediction models related to MeHg exposure were developed. Among them, the LightGBM model exhibited the best predictive performance, with an area under the curve (AUC) of 0.91 (95% CI 0.86-0.96) and an accuracy of 0.85 (95% CI 0.78-0.90). Its sensitivity, specificity, positive predictive value, negative predictive value, and F1 score all exceeded 0.82. Moreover, the interpretation of the SHAP model indicated that placental MeHg concentration was one of the most important predictors of NBDI occurrence. These findings reinforced existing epidemiological evidence on the association between MeHg exposure and NBDI, and fill a research gap regarding the health effects of MeHg exposure through rice consumption. They also provide an effective predictive tool for MeHg-related NBDI with clinical applicability.

Chemical pollution is a growing global threat, and freshwater habitats, which harbor disproportionate biodiversity and provide key ecosystem services, now face overlapping chemical and biological stressors whose combined effects can accelerate biodiversity loss. Fungicides, heavily used in forestry and agriculture, often leach to freshwater environments, but their impacts remain understudied, especially sub-lethal impacts such as changes in prey behaviour or detritivore-mediated decomposition. We examined the interactive effects of a widely used triazole fungicide (Tebuconazole) and a common biotic stressor (dragonfly predators) on a keystone detritivore, the freshwater isopod Asellus aquaticus, using a 2x2 factorial microcosm experiment in the laboratory. We reared isopods in groups in a combination of two fungicide (0 vs 50 μg/L Tebuconazole) and two predator (presence or absence of a caged predator) treatments and assessed changes in performance (behavioural activity, food consumption) after 21 days, followed by a survival assay in presence of a free-ranging predator. We found that Tebuconazole alone reduced feeding by 89 % and predator cues by 44 % relative to benign (clean water-no predator present) conditions, while both stressors together reduced feeding by 91 %, indicating that chemical stress overrode effects of predators. Isopods reared in the absence of a caged predator reduced their behavioural activity by 35 % when exposed to predator cues, whereas fungicide-exposed conspecifics showed no behavioural change, indicating impaired threat detection. Prior experience with predators nearly doubled survival against a free-ranging predator (45 % for predator-naive isopods vs 80 % for isopods reared with a caged predator), but this advantage vanished in the fungicide treatments (62 % survival). Collectively, our results demonstrate that environmentally relevant pesticide concentrations can change prey behaviour, increase predation risk, and potentially destabilize trophic interactions that regulate nutrient cycling. These findings underscore the need for freshwater risk assessments that capture how multiple interacting stressors affect organisms and the ecosystem functions they support.

Phthalic acid esters (PAEs), widely used plastic additives, have drawn significant scientific and regulatory attention due to their extensive use, environmental persistence, and potential endocrine-disrupting effects. Despite existing regulations to control the release and use of PAEs, their presence in marine ecosystems, particularly in cetaceans, remains a concern due to potential ecological and health impacts. In this work, the ammonium formate version of the QuEChERS method with slight modifications has been validated and applied for the determination of a group of 12 PAEs and one adipate in muscle, blubber, and brain tissues of stranded cetaceans in the Canary Islands. The method demonstrated satisfactory performance, with mean relative recovery values within the range 69-110 % and relative standard deviation values below 20%. Matrix-matched calibration curves yielded determination coefficients above 0.99 in all cases, with limits of quantification ranging from 0.21 to 16.03 ng/g. Matrix effects were generally soft (between -20 and 20%), except for butylbenzyl phthalate and dicyclohexyl phthalate in blubber, and di-n-octyl phthalate, diisononyl phthalate, and diisodecyl phthalate in brain tissue, where moderate effects (20-50%) were obtained. Dibutyl phthalate and di(2-ethylhexyl) phthalate (DEHP) were the only PAEs detected, primarily in blubber, with DEHP being the most prevalent analyte. However, concentrations were low (below 250 ng/g wet weight) and limited to muscle and/or blubber of Stenella frontalis, Stenella coeruleoalba, and Steno bredanensis.

The distribution of anthropogenic microparticles (AMPs) in marine sediments is still not well understood and characterized as chaotic, being influenced by too many factors, such as hydrodynamics, sediment characteristics, anthropogenic pressures, and AMPs properties. This study analyzes the contamination of bottom sediments along a 12-km longshore transect following the 25-m isobath in the southeastern Baltic Sea with AMPs (0.3-5 mm; fibers included; ZnCl used for separation; μ-Raman used for spectroscopic verification). A total of 55 samples from 19 stations were processed, revealing a mean blank corrected AMPs abundance of 271±214 items/kg dry weight (737±598 items/kgDW without correction, more than 97% fibers). Alongside the AMPs abundance, size and shape distributions, the sediment grain size distribution, coarseness, and sorting were analysed. Under similar environmental conditions along the transect, the strongest and statistically significant correlation was found between the abundance of fibers and sediment grain size in the range of 50-100 μm. Although fiber content increased with decreasing sediment grain size, no correlation was found with the percentage of the clay-silt fraction (<63 μm). In light of experimental studies of AMPs and sediment particle hydrodynamics, a possible scenario of AMPs hotspot formation was discussed.