Search Results (602)

Human health risk assessment of vapor intrusion caused by organic pollutants is commonly based on steady-state predictions of partition and vapor migration in the subsoil. This study develops a pseudo-dynamic, process-based Partition–Diffusion Risk Model (PDRM) using a one-dimensional numerical model for organic mixtures to assess the time evolution of cancer and non-cancer risks, indoor air concentrations, and non-aqueous phase liquid (NAPL) formation. The model has been applied to a low-carbon sandy soil without microbial degradation, which might be a worst-case scenario. Six simulation scenarios combined two source concentrations (1000 and 3000 mg/kg) and three source depths (1, 3, and 5 m) over 30 years. Results show that source depth governs exposure dynamics: shallow contamination poses unacceptable risks rapidly but declines quickly, whereas at greater depths, unacceptable levels appear later and persist throughout the exposure period. NAPL formation may act as a secondary source, sustaining vapor release and extending indoor exposure under high-loading conditions. Multicomponent partitioning induces nonlinear, compound-specific behavior, with the first 3–5 years representing a critical period for rapid risk changes. Conventional models show that neglecting NAPL formation and time variability may lead to an underestimation of cancer risk by up to an order of magnitude. These findings highlight the importance of incorporating depth and time-dependent characterization to reduce uncertainty in vapor intrusion risk assessments. Full article

Water resources are essential for human well-being. However, water pollution is a major global problem with significant implications for the environment and public health. To address these challenges, this study presents an integrated perspective on water pollution by correlating pollution sources, transport pathways, exposure routes, and associated risks to human health. The methodology combined a systematic review conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with a bibliometric analysis performed by using VOSviewer version 1.6.19, a software tool for constructing and visualizing bibliometric networks. A total of 332 publications published between 2015 and 2025 were retrieved from the Scopus and Google Scholar databases and met the PRISMA eligibility criteria. The findings indicate that both natural and anthropogenic sources contribute to water contamination, introducing pollutants such as heavy metals, pesticides, pharmaceutical residues, microplastics, and pathogenic microorganisms with potential human health impacts. Bibliometric analysis revealed a transition from conventional water quality assessments toward integrated approaches emphasizing health risks and environmental interactions. The study further identified important knowledge gaps regarding contaminant mixture effects and synergistic toxicity, which remain insufficiently addressed in current scientific and regulatory frameworks. These findings highlight the need for strengthened regulatory strategies, advanced treatment technologies, and evidence-based water governance to support environmental sustainability and public health protection. Full article

This study evaluated the reliability and application of relative potency factors (RPFs) for assessing hepatic mixture risks of per- and polyfluoroalkyl substances (PFASs) in Korean finished drinking water. A total of 1254 finished water samples collected from 70 drinking water treatment plants between 2018 and 2024 were analyzed for eight PFAS compounds. Hepatic RPFs proposed by the National Institute for Public Health and the Environment (RIVM) were assessed using a structured scoring system and applied to estimate PFOA-equivalent mixture risks. Hazard quotients (HQs) based on hepatic toxicity reference doses were also calculated for comparison. PFAS concentrations generally declined over time, including PFOA from 0.0032 to 0.0014 μg/L, PFOS from 0.0008 to 0.0003 μg/L, and PFHxS from 0.0072 to 0.0004 μg/L between 2018 and 2024. The RPF-based method produced higher cumulative risk estimates than the individual toxicity-based approach, suggesting that single-compound HQs may underestimate risks from co-occurring PFASs. Although total risks were generally below the non-carcinogenic threshold of 1.0, the 95th percentile PFOA-equivalent risk for PFNA exceeded the individual threshold of 0.1. These findings support endpoint-specific RPF-based assessment for PFAS mixtures in drinking water. Full article

An emerging environmental pollutant, microplastics have garnered global attention due to their widespread presence in soil and aquatic ecosystems. Early research primarily treated microplastics as single pollutants, focusing on their individual toxic effects. However, microplastics in the environment exist as a complex mixture, comprising various polymer types, sizes, shapes, and aging states. This diversity influences how microplastics regulate ecosystem carbon and nitrogen cycles and intervene through pathways such as direct carbon input, physical disturbance, microbial community restructuring, and coupled effects. This paper systematically reviews the characteristics of microplastic diversity and its mechanisms influencing carbon and nitrogen cycles: the chemical structure of polymers determines bioavailability and degradation rate, with biodegradable plastics altering carbon and nitrogen transformations more significantly than conventional plastics; microplastics of different sizes affect nitrogen transformation dynamics by modulating specific surface area and microbial colonization, with small-sized biodegradable microplastics particularly inhibiting plant nitrogen uptake; aging modifies surface properties and dissolved organic carbon release, thereby enhancing their role in promoting greenhouse gas emissions. Existing studies are largely confined to short-term laboratory simulations, leaving a gap in understanding the comprehensive effects of microplastic diversity under long-term, field conditions. Future research should focus on standardized methods and long-term experiments with multi-factor coupling to provide a scientific basis for ecological risk assessment of microplastic pollution. Full article

Polycyclic aromatic hydrocarbons (PAHs) represent a major class of ubiquitous environmental pollutants, posing significant risks to ecosystems and human health due to their persistence, toxicity, and potential for bioaccumulation. This review provides a comprehensive synthesis of current scientific knowledge on PAHs, integrating insights from chemical kinetics, environmental fate, and toxicological mechanisms. The fundamental structural chemistry of PAHs and its direct influence on their physicochemical properties and environmental properties are discussed. The major anthropogenic and natural sources of PAHs are detailed, alongside the chemical kinetics behind their formation during incomplete combustion and their transformation in environmental media. Unlike previous reviews that address PAH sources, remediation, or health effects as separate topics, this review uniquely traces the mechanistic continuum from molecular formation kinetics through physicochemical partitioning and environmental transport to toxicological endpoints, providing a causally linked framework for understanding how structural properties ultimately determine biological outcomes. A central focus is placed on the environmental fate and transport of PAHs across atmospheric, aquatic, and terrestrial compartments, highlighting processes such as gas–particle partitioning, sediment accumulation, and long-range transport. The review further elucidates the complex toxicological pathways of PAHs, including metabolic activation to reactive intermediates, DNA adduct formation, oxidative stress, and their roles in carcinogenesis and other systemic health effects. The analysis reveals strong scientific consensus on the carcinogenic mechanism of parent PAHs via CYP450-mediated metabolic activation to diol-epoxide intermediates while identifying critical areas of uncertainty: the current regulatory framework based on 16 priority PAHs underestimates total carcinogenic risk by a factor of 2–5, mixture toxicology remains poorly characterized, and dose–response relationships for non-cancer endpoints (cardiovascular, neurodevelopmental, immunotoxic) lack the quantitative data needed for robust risk assessment. Finally, human exposure pathways and health risk characterization approaches are discussed, highlighting the need for cumulative, mixture-based assessment frameworks. Full article

The presence of organic micropollutants such as pharmaceuticals and pesticides in aquatic systems poses risks to environmental and public health, as conventional wastewater treatment plants are often ineffective at removing them, highlighting the need for alternative solutions. This study evaluates the combined use of biochar and laccase to remove trimethoprim, clindamycin, and fipronil, selected for their ubiquity, persistence, and physicochemical properties. Commercial wood-derived biochar was used, and removal performance was assessed through adsorption isotherms, time-dependent evaluation of removal efficiency, and quantification by UPLC-MS/MS. Toxicity after treatment was evaluated using bacterial growth assays with Escherichia coli and Rhodococcus erythropolis. Adsorption of trimethoprim and clindamycin followed the Langmuir model (Qmax 2.27 and 1.49 mg/g), while that of fipronil followed the Temkin model (Qmax 0.98 mg/g). The combined biochar–laccase system enabled up to 99% removal of trimethoprim and clindamycin within one hour, demonstrating synergy between adsorption and enzymatic removal. Enhanced removal was also observed for clindamycin and fipronil in mixtures. Bacterial assays showed partial restoration of growth after treatment, suggesting reduced antibacterial activity of transformation products, although effects remained species-dependent. Overall, the biochar–laccase system shows promise for micropollutant removal, supporting green remediation strategies, but further work is required to characterize transformation products and assess ecological impacts. Full article

This paper introduces a random activation framework for cure rate modeling that provides a novel latent mechanistic interpretation of the standard mixture cure model, utilizing a Waring-distributed number of latent causes. The proposed approach represents unobserved heterogeneity through a discrete latent variable interpreted as the number of potential risk factors, providing a flexible and biologically interpretable characterization of individual susceptibility. In contrast to classical competing risks models based on extremal operators or deterministic activation schemes, the event time is assumed to arise from a stochastic selection among latent causes. This random activation mechanism defines a unified probabilistic framework in which the cure fraction emerges naturally as the probability of having zero latent causes. The Waring distribution is adopted to model the latent count structure due to its hierarchical formulation, which accommodates overdispersion and heavy-tailed behavior strictly within the latent parametrization of individual risk factors. Under this framework, while the population survival function mathematically reduces to the classical mixture cure representation, the model provides an alternative structure where covariates directly impact the expected latent burden. Parameter estimation for the identifiable regression structure is performed via maximum likelihood, and the finite-sample performance of the estimators is assessed through Monte Carlo simulations, showing accurate parameter recovery and stable inferential properties. An application to real survival data illustrates the practical relevance and epidemiological interpretability of the proposed framework. Overall, this work extends the understanding of existing cure rate models by integrating latent count structures and stochastic activation within a coherent setting, providing a powerful interpretation tool for heterogeneous survival data with long-term survivors. Full article

The adoption of exhaust gas cleaning systems (scrubbers) in maritime transport generates a complex metal-laden washwater that may pose a noteworthy threat to marine ecosystems. This study assessed the acute toxic effects (LC₅₀, 48 h) of four prevalent metals detected in scrubber washwater—vanadium (V), iron (Fe), nickel (Ni), and zinc (Zn)—both individually and as a realistic mixture. For this purpose, multiple life stages of Artemia franciscana (nauplii, juveniles, and adults) and the rotifer Brachionus plicatilis have been tested under laboratory conditions. All metals induced concentration-dependent toxicity, but sensitivities varied through life stages and species tested. The sensitivity to contaminants generally decreased as the organism’s developmental stage progressed. Consequently, three different orders of toxicity can be detected. The order of metal toxicity (from highest to lowest toxicity, based on 48 h LC₅₀ values) was V > Fe > Ni > Zn for nauplii; V > Zn > Fe > Ni for juveniles and adults; and Fe > V > Zn > Ni for B. plicatilis. The Cumulative Toxic Unit (CTU) approach was utilized to compare the predicted additive effect with observed mixture toxicity. This analysis revealed a complex, life stage-dependent interaction; while antagonism dominated in nauplii (suggesting chemical mitigation), juveniles and adults of A. franciscana and the rotifer (B. plicatilis) exhibited significant synergism, amplifying the total toxicity beyond prediction. This study demonstrates that early life stages and small zooplankton are the most sensitive bioindicators of scrubber-related metal contamination, highlighting the potential ecological risk posed by metal-rich, acidic scrubber discharges that may enhance metal bioavailability and toxicity in marine environments. Full article

Duckweed (Lemnaceae) is a promising alternative feed crop, particularly in regions with nutrient surpluses and protein deficits, as it grows efficiently on nutrient-rich agricultural wastewater and provides protein-rich biomass. However, its high moisture content and rapid post-harvest spoilage pose major storage challenges. This study evaluated (co-)ensiling as a cost-effective preservation strategy for duckweed. Three separate experiments were conducted to assess the ensilability of duckweed alone and in combination with various agricultural co-substrates and additives, including corn silage, beet pulp, grass silage, hemp shives, hay, molasses, sun-dried duckweed and CaCO₃. Duckweed alone could not be successfully ensiled due to excessive moisture, resulting in poor acidification and high levels of undesirable fermentation products. During the long-term co-ensiling test, a duckweed–corn silage mixture containing 29% fresh duckweed and 71% corn silage showed the most stable fermentation profile, with low pH, limited fermentation losses, and no detectable butyric acid. A duckweed–grass silage mixture containing 51% fresh duckweed and 49% grass silage allowed higher duckweed inclusion and retained the highest level of apparent pepsin-digestible protein after storage, but showed elevated acetic acid and ethanol concentrations. A duckweed–beet pulp mixture containing 74% fresh duckweed and 26% beet pulp enabled the highest duckweed inclusion rate, but showed signs of clostridial fermentation, likely due to excess moisture. Microbiological analysis of this beet pulp mixture showed reduced Enterobacteriaceae after ensiling, but also increased clostridial counts. Oxalic acid concentrations were low in all duckweed-based silages, with the largest reduction observed in the duckweed–grass mixture. Overall, the results show that duckweed co-ensiling is feasible but highly dependent on co-substrate selection and moisture control. Further formulation optimisation is required, particularly for high-duckweed mixtures, to reduce the risk of clostridial fermentation and improve practical applicability as a storable feed ingredient. Full article

Pigment implantation (semi-permanent make-up, microblading and cosmetic tattooing) introduces complex pigment mixtures into the dermis, resulting in direct exposure of keratinocytes, fibroblasts and resident immune cells to metals, organic dyes and nanoparticles. Within Somatology and Somatic therapy practice, an allied health discipline concerned with evidence-based care of the skin and body, Somatic Therapists operate at the interface of dermal intervention, molecular exposure and occupational health, underscoring the relevance of mechanistic toxicology for risk-informed professional practice. This PRISMA-guided systematic review synthesises molecular toxicology and omics-based evidence, emphasising oxidative stress generation, inflammatory signalling via NF-κB/MAPK pathways, apoptosis and genotoxicity, T-cell-mediated type IV hypersensitivity reactions associated with modern red azo pigments, and dermal-to-lymphatic transport of particulate matter. Transcriptomic and metabolomic studies consistently demonstrate pigment-specific inflammatory responses and wound-healing gene signatures, supporting mechanism-driven biocompatibility profiling. Regulatory frameworks, including EU REACH Annex XVII Entry 75 and recent FDA guidance on microbial contamination, have strengthened compliance requirements; however, surveillance continues to identify mislabelling, restricted pigments and microbial contamination in some inks. For Somatology and Somatic therapy practice, these findings highlight the importance of evidence-based pigment selection, traceable sourcing, aseptic technique, ventilation, personal protective equipment and informed consent addressing pigment migration and delayed adverse reactions. The integration of molecular outcomes with omics technologies and regulatory oversight provides a next-generation risk assessment framework to advance safe cosmetic practice and public health. Full article

Microplastic (MP) contamination has become a defining feature of twenty-first century environmental change, yet the toxicological and ecological consequences for amphibians and reptiles—two vertebrate classes already facing severe extinction pressures—remain fragmented across taxa, regions, and methodological traditions. Here, we synthesize field and experimental evidence from five continents to provide a taxonomically balanced, mechanistically grounded, and geographically explicit assessment of MP exposure, bioaccumulation, and toxicity in herpetofauna, drawing on a structured literature search in Web of Science, Scopus, and PubMed (January 2015—March 2026). Field detection rates of MPs in amphibian larvae range from 26% in conservatively screened Central European populations to 73–80% in anuran tadpoles from high-anthropogenic-pressure Anatolian catchments, with fibrous polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP) particles dominating the detected burden. Mechanistic evidence converges on oxidative stress cascades, hypothalamic–pituitary–thyroid axis disruption, gut and cutaneous microbiome dysbiosis, and compromised antiviral and antifungal immunity, with the latter potentially amplifying vulnerability to Batrachochytrium dendrobatidis and to ranavirus. Among reptiles, sea turtles display near-universal MP ingestion with documented maternal transfer to eggs; freshwater turtles, terrestrial squamates, and crocodilians remain critically understudied. Three structural asymmetries constrain current ecotoxicological risk characterization: taxonomic bias toward anurans and sea turtles, geographic bias toward the Global North, and experimental bias toward acute, supra-environmental laboratory exposures using pristine, single-polymer particles that fail to capture the chemical complexity of weathered field mixtures. We argue that MP burden may warrant consideration as a candidate stressor criterion within IUCN Red List assessments and within environmental risk assessment frameworks for freshwater and terrestrial biodiversity once a robust quantitative relationship between MP burden and demographic decline or population-level fitness has been established, and propose six hypothesis-driven research priorities: methodological standardization, reptile toxicokinetics, transgenerational epigenetics, MP–pathogen microbiome interactions and their translation into population viability models, temperature × MP interaction under climate warming, and population-genetic consequences of contemporary MP-driven selection, as the most tractable avenues for ecotoxicological progress and for the development of herpetofauna-specific risk characterization frameworks. Full article

Background/Objectives: Denture disinfection is a crucial step in reducing microbial colonization and the risk of denture stomatitis, as well as contributing to patient health and denture longevity; thus, it was obligatory to select an effective cleanser without undesirable impact on properties of acrylic denture base material. This study aimed to assess the synergistic effect of white vinegar and sodium bicarbonate (WVSB) mixture on Candida albicans by means of colony forming unit (CFU) and adhesion assays, as well as the surface roughness and flexural strength of heat-cured acrylic denture base material after being immersed in the WVSB mixture. Methods: In total, 200 specimens of heat-cured acrylic resin were prepared: 50 per each test, 5 per each group. They were divided into ten groups; distilled water (negative control), a Corega denture cleanser tablet soaked for 5 min (positive control), and four concentrations (2%, 3%, 4% and 5%) of WVSB mixture were made and examined for (5 and 10 min) immersion durations. Statistical analysis was performed by using Welch’s ANOVA alongside Games–Howell post hoc tests for CFU assay and one-way ANOVA along with Tukey HSD post hoc tests for remaining tests. A p < 0.05 was considered significant in all experiments. Results: The results for the CFU, adhesion and surface roughness tests showed that the WVSB mixture demonstrated a statistically significant difference in most test groups compared to the negative control group, while the flexural strength test showed a statistically non-significant difference. Conclusions: The WVSB mixture showed concentration and time-dependent antifungal effects against C. albicans, with increased surface roughness and no negative effect on the flexural strength of heat-cure acrylic. Full article

Polycyclic aromatic hydrocarbons (PAHs) in water are readily adsorbed onto microplastics, posing a combined threat to aquatic ecosystem safety. However, the role of microplastics in altering the toxicity of PAH derivatives remains largely unexplored. This study was conducted to investigate the individual and combined toxic effects of polystyrene (PS, 2 µm) microplastics with pyrene (Pyr) and its four derivatives, including 1-methylpyrene (Pyr–CH₃), 1-hydroxypyrene (Pyr–OH), 1-aminopyrene (Pyr–NH₂), and 1-pyrenecarboxylic acid (Pyr–COOH), on blue mussels (Mytilus edulis). After a seven-day exposure experiment, the variations in five biomarkers—superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), malondialdehyde (MDA), and acetylcholinesterase (AChE)—were measured in the hemolymph. Our results indicated a com-pound-specific toxicological profile: all derivatives exhibited higher toxicity than the parent Pyr. Specifically, Pyr–CH₃ primarily induced oxidative stress, whereas Pyr–OH, Pyr–NH₂, and Pyr–COOH mainly affected neuroregulatory function. More importantly, PS microplastics acted as a differential modulator under the mixture conditions: they exacerbated the neuroregulatory dis-turbance caused by parent Pyr but conversely alleviated the oxidative damage induced by all four derivatives. Notably, PS exacerbated the neuroregulatory disturbance induced by Pyr–CH₃. These compound-specific interactions highlight that microplastics alter the toxic effects of organic pollutants, thereby modifying environmental risk profiles. Our findings provide new insights for the ecological risk assessment of PAHs in aquatic environments. Full article

Phthalic acid esters (PAEs), ubiquitous plasticizers and recognized endocrine-disrupting chemicals, pose a protracted threat to aquatic ecosystems and biodiversity. However, current ecotoxicological assessments often focus on isolated chemicals at exceedingly high laboratory doses, failing to reflect true environmental risks. This review systematically evaluates and compares the multisystemic toxicological effects of six priority PAEs (DEHP, DBP, BBP, DNOP, DEP, and DMP) using the zebrafish biological model. The synthesized evidence reveals a distinct structure–activity relationship, where long-chain and highly hydrophobic congeners exhibit substantially higher toxicity than their short-chain counterparts. Exposure to these PAEs induces severe developmental, cardiovascular, neurobehavioral, and reproductive anomalies. Specifically, DBP and BBP display the most potent cardiotoxic and neurotoxic effects, while DEHP and DBP drive profound reproductive decline and endocrine disruption at concentrations as low as 0.5–20 μg/L. Crucially, comparative environmental relevance assessments indicate that real-world PAE concentrations in industrial hotspots frequently meet or exceed these laboratory-derived lowest observed effect concentrations. These findings underscore the severe ecological risks posed by PAE contamination and position the zebrafish as a vital biological sentinel. Future ecotoxicological evaluations must prioritize chronic, low-dose mixture exposures and transgenerational toxicity to fully characterize the protracted legacy of these pollutants on zebrafish populations. Full article

As a key enabler for carbon neutrality, hydrogen-blended natural gas utilization requires a thorough safety assessment. This study investigates leakage dispersion in a typical kitchen (4 m × 3 m × 2.8 m) using validated CFD methods. Simulations examined coupled effects of hydrogen blending ratios (0–20%), leakage types (pipe cracks/hose pinholes), and ventilation conditions. Results show hydrogen enrichment accelerates overall dispersion but intensifies methane accumulation near the source. In all scenarios, buoyancy-driven stratification formed stable combustible layers (>0.3 m thick) exceeding the mixture-specific lower flammability limit (recalculated using Le Chatelier’s law) after 25 min in confined spaces. While ventilation promoted global diffusion, it created persistent high-concentration zones (≥5% volume fraction) near leakage sources. The spatial overlap of these hazardous clouds with ignition sources significantly increases explosion risks. This research provides critical insights for developing safety standards and emergency protocols for hydrogen–natural gas mixtures. Full article