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.

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.

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.

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.

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.

The formation of thioantimonates in sulfidic waters significantly increases the complexity of antimony (Sb) geochemistry, yet the factors controlling their prevalence in natural systems remain poorly constrained. This study systematically examined the competitive thiolation kinetics among Sb, arsenic (As), and tungsten (W), elements that commonly coexist in sulfidic geothermal waters. Experimental results demonstrate that under sulfide-limited conditions, the kinetics sequence is As > Sb ≈ W, while the kinetic stability of the resulting thio-anions follows thioarsenates > thioantimonates > thiotungstates. This coupled kinetic-stability framework successfully explains the distribution of Sb speciation observed in representative sulfidic hot springs within the Yunnan-Sichuan-Tibet geothermal province (China), where high Sb concentrations (4.32 - 2128.7 μg/L) originate from rock leaching and magmatic fluids. In sulfide-deficient hot springs, coexisting As and W act as inhibitors of Sb thiolation through competitive exclusion, leading to oxyanion dominance; conversely, in sulfide-sufficient hot springs, they become promoters, enhancing thioantimonates formation (up to 56.6% of total Sb) potentially through an ionic strength effect. Our findings redefine the competitive thiolation hierarchy among Sb, As, and W and provide a quantitative framework for predicting Sb speciation in sulfidic environments, which is critical for assessing its environmental fate.

Although the prenatal life is a critical period for brain development, very few studies have focused on prenatal exposure to air pollution in relation to infant cognition, and most studies have relied on carer-reported outcome assessment. We examined the association between prenatal exposure to air pollution and objective measurement of infant cognitive development using an eye-tracking methodology. The study was based on data from a subset of 168 mother-child pairs participating in the Barcelona Life Study Cohort (BiSC), Spain (2018-2023). Total exposure to nitrogen dioxide (NO), black carbon (BC), particulate matter (PM), and PM copper (Cu) and iron (Fe) content during pregnancy were assessed through integrating estimates of land-use regression (LUR) models with data on time spent at home, workplace, and during commuting. Cognitive performance was assessed longitudinally at 6 months (n=156) and 18 months (n=62) of age through an eye-tracking Visual Paired-Comparison (VPC) task that measured short-term recognition memory for faces. Linear mixed models were applied to explore the association between prenatal air pollution exposure and the percentage looking time at novel compared to familiar stimuli on the VPC task, adjusting for potential confounders. Results showed worse cognitive performance with increasing air pollution exposure: For each interquartile range increase of NO, BC, PM, Cu and Fe, novelty preference decreased with -2.0 (95% CI: -4.7, 0.6), -2.5 (-4.6, -0.5), -3.9 (-7.0, -0.9), -2.1 (-4.0, -0.3), and -1.4 (-3.2, 0.3), respectively. There were suggestions for potentially stronger associations in boys. The findings highlight the pregnancy period as a window of vulnerability for the impact of air pollution on the developing brain, and values eye-tracking as an objective non-invasive tool for early detection of such impact.

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.

PM pollution, driven by various human activities, has become a significant global threat to both environmental and public health, yet accurately predicting its health burden remains challenging due to the complex interplay of multiple influencing factors. To overcome the limitations of traditional models, including their inability to capture spatial non-stationary relationships, weak spatial interpretability, and dependence on densely distributed training data, this study proposes a hybrid forecasting framework based on Geographical Neural Network Weighted Regression. Based on global PM exposure and health data from 2000 to 2021, we integrated graph neural networks with spatially adaptive regression techniques to construct a hybrid model. This model effectively captures the spatial heterogeneity of PM-related health burden and reveals its driving factors. The results showed that PM-related mortalities were estimated to have increased by 57.25% by 2021 and are projected to rise by an additional 12.84% by 2030, with hotspots concentrated in low- and middle-income countries. The Health index was identified as the most influential factor (34.87%), although interactions among Health, Income, and Material indicators varied by country. This study provided an interpretable model to support early warning systems and evidence-based public health strategies.

Rare earth elements (REEs) are increasingly recognized as emerging environmental contaminants due to their expanding use in electronics, renewable energy, medical devices, and fertilizers. This systematic review synthesizes current knowledge on REE concentrations in free-ranging wildlife from aquatic and terrestrial ecosystems. We analyzed 95 peer-reviewed studies (1976-2025) selected from Scopus and Web of Science using PRISMA 2020 guidelines, evaluating geographic distribution, taxonomic coverage, trophic level, tissue type, analytical methods, and data reporting. The number of publications increased sharply after 2011, with most studies focused on aquatic organisms and European countries. Notably, countries with large REE reserves, such as Vietnam, Russia and India, were underrepresented. Research concentrated on three aquatic taxa: Actinopterygii (ray-finned fishes), Bivalvia (clams and mussels), and Malacostraca (crabs and shrimp). REE concentrations were typically higher in organisms at lower trophic levels and in benthic species, supporting trophic dilution. In vertebrates, liver, kidney, and gills showed the highest REE concentrations, while non-invasive samples such as feathers and feces, although lower concentrations, demonstrated potential for biomonitoring. Methodological inconsistencies in subgroup classification, normalization, and statistical reporting limit cross-study comparability. This review highlights major knowledge gaps, especially in terrestrial ecosystems and agricultural areas exposed to REEs via fertilizers. Future research should prioritize broader taxonomic and geographic coverage and standardized methods. Given their persistence and dual role as both tracers and contaminants, REEs warrant integration into long-term monitoring to clarify their ecological and toxicological effects.

This study addressed the development of a user-friendly web-based tool to quantify the deposition of particulate matter (PM) during exercise followed by a functional test. The "PM-Quantifier" was developed with open-source technologies and hosted on an institutional server for long-term sustainability. The system was based on a mathematical model for particle deposition from user input, including, age, height, sex, as well as the particle concentration. The exercise parameters include mean minute ventilation () or heart rate values of exercise, and the duration of the task. The accuracy was confirmed by cross-checking against a reference Python script and tested with a large Monte Carlo Method-generated dataset (n=20,000). PM-Quantifier is hosted at the Federal University domain and may be accessed on https://pmquantifier.ufsc.br/ by desktop and mobile devices. Lastly, the functional tests were also performed to verify the potential use of the PM-Quantifier for scientific purposes. Indeed, based on our regression model, the total particle deposition during a simulated physical exercise task was mostly explained by ) (52.0% for males, and 52.8% for females) and duration of the task (47.5% and 46.7%, respectively). The PM-Quantifier was successfully developed and tested, being considered an easy-to-use and friendly tool for scientific and general population use. Our functional tests outcomes are aligned with the best scientific knowledge about air pollution and particle deposition while exercising, in what the exposure duration and ) are the primary drivers of particle deposition.

Beyond regulating glucose metabolism and energy homeostasis, insulin dysregulation impairs mammalian fertility by disrupting hormone secretion, but its role in fish reproduction remains poorly characterized. Here, a transcriptome-based systematic review of 19 studies revealed that exposure to pollutants (bisphenols) caused dual changes in insulin signaling and reproductive processes across species, suggesting a potential mechanistic link. Bisphenols (BPs) are a typical class of endocrine-disrupting chemicals. Molecular docking assessed binding affinities of ten BPs to insulin and its receptor across species, with BPZ and BPM showing stronger affinities than BPA. Juvenile Chinese rare minnows (Gobiocypris rarus) were exposed to BPA, BPZ, or BPM (1-100 μg/L) for 60 days. The reproductive development including reduced gonadosomatic index, inhibited oogenesis, and enhanced spermatogenesis were impaired at all treatments. Moreover, insulin-related gene expression along the HPG axis was altered, accompanied by suppressed insulin and disrupted sex hormone levels. Spearman correlation analysis revealed strong correlations between insulin and HPG axis hormones in males (r = 0.41 -0.90, p = 0.02-0.21) and fair correlations in females (r = 0.48-0.61, p = 0.11-0.23). Those findings indicated that bisphenols-induced reproductive toxicity maybe mediated by insulin homeostasis disruption.

Polystyrene microplastics (PS MPs) are prevalent marine pollutants with documented toxicity in aquatic organisms. However, their impacts on vertebrate skeletal development, particularly in fish, remain poorly understood. This study investigated the effects of chronic (28-day) exposure to PS MPs (7.3 μm; 0, 0.2, 2, 20 mg L) on skeletal development in marine medaka (Oryzias melastigma). Fluorescence imaging and histology confirmed PS MP bioaccumulation, primarily in the intestine and gills. Behavioral analysis revealed concentration-dependent alterations, including initial hyperactivity and subsequent hypoactivity at low doses. Micro-computed tomography and histopathology demonstrated significant vertebral abnormalities, reduced bone volume/surface, and impaired mineralization at higher concentrations, while a low dose induced enhanced bone formation. Scanning electron microscopy with energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy revealed disrupted mineralization, decreased Ca/P ratios, and altered collagen/mineral matrix composition. Gene expression analysis indicated dysregulation of osteogenic (Runx2, Sp7, Bmp4, AcvR1b), osteoclastic (Ctsk), and morphogenic (Shh) pathways. These multi-scale findings demonstrate that PS MPs impair skeletal development through disrupted mineralization, matrix abnormalities, and inflammation. The observed non-monotonic dose responses highlight complex chronic toxicity mechanisms, posing significant ecological risks to marine fish populations.

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.

Taste and odor events in lacustrine systems, primarily driven by 2-methylisoborneol (2-MIB), pose a global challenge to drinking water safety. In this study of eastern Lake Taihu, we conducted synchronous monitoring of 2-MIB concentrations, environmental parameters, and the abundance of genes associated with odor production in bacteria in surface water, bottom water, and sediment porewater from April to December 2023. Our findings revealed a steep vertical concentration gradient, with 2-MIB in sediment porewater reaching a peak mean concentration of 1150 ng/L in August, a level over four times higher than that in the overlying surface water (280 ng/L). Piecewise structural equation modeling (SEM) quantitatively confirmed a distinct "bottom-up" transport pathway. Porewater 2-MIB concentrations directly influenced bottom-water levels (path coefficient, β=0.37), which in turn were the primary determinant of surface-water concentrations (β=0.93). Furthermore, our analysis unveiled divergent mechanisms driving 2-MIB dynamics; concentrations in the overlying water were strongly correlated with aquatic primary productivity, whereas those in porewater depended on the distinct biogeochemical environment of the sediment layer. This study shows that the sediment is a key internal source of 2-MIB in eastern Lake Taihu. We reveal a bottom-up transport pathway that drives odor pollution in the overlying water, providing critical scientific insights for managing taste and odor problems in shallow lake ecosystems.

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 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.

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.

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.

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.

Due to their high stability and water solubility, some artificial sweeteners reach aquatic environments and persist there. Despite the identification of sucralose, acesulfame, saccharin, and cyclamate as emerging pollutants in literature for over a decade, no environmental risk assessment of these substances has been conducted to date. However, the European Food Safety Authority (EFSA) is currently undertaking a re-evaluation of the authorization of artificial sweeteners, still ongoing for sucralose and cyclamate. The present review demonstrates that all four sweeteners have been identified as being persistent and very mobile in the aquatic environment. The focal point of this review pertains to the ecotoxicity of the four aforementioned sweeteners. The acute toxicity studies conducted on aquatic model organisms demonstrated that there was no overall acute hazard. Nevertheless, a pronounced lack of chronic toxicity studies persists, and data at environmentally relevant concentrations remain scarce, representing a significant knowledge gap. This is a matter of concern, as this review indicates that numerous studies employing alternative endpoints have identified effects within environmentally relevant concentrations. In light of the potential for long-term effects, the reauthorization of the addressed artificial sweeteners warrants careful reconsideration.