Toxics

Assessing the Impact of Aviation Emissions on Air Quality at a Regional Greek Airport Using Machine Learning
Stefanis C, Manisalidis I, Stavropoulou E, Stavropoulos A, Tsigalou C, Voidarou CC, Constantinidis TC and Bezirtzoglou E
Aviation emissions significantly impact air quality, contributing to environmental degradation and public health risks. This study aims to assess the impact of aviation-related emissions on air quality at Alexandroupolis Regional Airport, Greece, and evaluate the role of meteorological factors in pollution dispersion. Using machine learning models, we analyzed emissions data, including CO, NOx, CO, HC, SOx, PM, fuel consumption, and meteorological parameters from 2019-2020. Results indicate that NOx and CO emissions showed the highest correlation with air traffic volume and fuel consumption (R = 0.63 and 0.67, respectively). Bayesian Linear Regression and Linear Regression emerged as the most accurate models, achieving an R value of 0.96 and 0.97, respectively, for predicting PM concentrations. Meteorological factors had a moderate influence, with precipitation negatively correlated with PM (-0.03), while temperature and wind speed showed limited effects on emissions. A significant decline in aviation emissions was observed in 2020, with CO emissions decreasing by 28.1%, NOx by 26.5%, and PM by 35.4% compared to 2019, reflecting the impact of COVID-19 travel restrictions. Carbon dioxide had the most extensive percentage distribution, accounting for 75.5% of total emissions, followed by fuels, which accounted for 24%, and the remaining pollutants, such as NOx, CO, HC, SOx, and PM, had more minor impacts. These findings highlight the need for optimized air quality management at regional airports, integrating machine learning for predictive monitoring and supporting policy interventions to mitigate aviation-related pollution.
Biomonitoring-Based Risk Assessment of Pyrethroid Exposure in the U.S. Population: Application of High-Throughput and Physiologically Based Kinetic Models
Hsieh NH and Kwok ESC
Pyrethroid insecticides have been extensively utilized in agriculture and residential areas in the United States. This study evaluated the exposure risk by age using available biomonitoring data. We analyzed pyrethroid metabolite concentrations in urine using the National Health and Nutrition Examination Survey (NHANES) data. Reverse dosimetry was conducted with a high-throughput model and a physiologically based kinetic (PBK) model integrated with a Bayesian inference framework. We further derived Benchmark Dose (BMD) values and systemic points of departure in rats using Bayesian BMD and PBK models. Margins of exposure (MOE) were calculated to assess neurotoxic risk based on estimated daily oral intake and dose metrics in plasma and brain. Results from both models indicated that young children have higher pyrethroid exposure compared to other age groups. All estimated risk values were within acceptable levels of acute neurotoxic effect. Additionally, MOEs calculated from oral doses were lower than those derived from internal doses, highlighting that traditional external exposure assessments tend to overestimate risk compared to advanced internal dose-based techniques. In conclusion, combining high-throughput and PBK approaches enhances the understanding of human health risks associated with pyrethroid exposures, demonstrating their potential for future applications in exposure tracking and health risk assessment.
The Hidden Legacy of Dimethoate: Clay Binding Effects on Decreasing Long-Term Retention and Reducing Environmental Stability in Croatian Soils
Karleuša R, Marinić J, Tomić Linšak D, Dubrović I, Antunović D and Broznić D
Understanding the dynamics of sorption and desorption is essential for assessing the persistence and mobility of pesticides. These processes continue to influence ecological outcomes even after pesticide use has ended, as demonstrated by our study on dimethoate behavior in distinct soil samples from Croatia, including coastal, lowland, and mountainous regions. This study focuses on the sorption/desorption behavior of dimethoate in soil, explores the relationship between its molecular structure and the properties of soil organic and inorganic matter, and evaluates the mechanisms of the sorption/desorption process. The behavior of dimethoate was analyzed using a batch method, and the results were modeled using nonlinear equilibrium models: Freundlich, Langmuir, and Temkin models. Soils with a higher organic matter content, especially total organic carbon (TOC), showed a better sorption capacity compared to soils with a lower TOC. This is probably due to the less flexible structures in the glassy phase, which, unlike the rubbery phase in high TOC soils, do not allow dynamic and flexible binding of dimethoate within the organic matter. The differences between the H/C and O/C ratios indicate that in high TOC soils, flexible aliphatic compounds, typical of a rubbery phase, retain dimethoate more effectively, whereas a higher content of oxygen-containing functional groups in low TOC soils provides strong association. The lettered soils showed stronger retention of dimethoate through interactions with clay minerals and metal cations such as Mg, suggesting that clay plays a significantly more important role in enhancing dimethoate sorption than organic matter. These results highlight the importance of organic matter, clay, and metal ions in the retention of dimethoate in soil, indicating the need for remediation methods for those pesticides that, although banned, have had a long history of use.
Infants' Dermal Exposure to Phthalates from Disposable Baby Diapers and Its Association with DNA Oxidative Damage
Lai X, Zhu J, Liu Y, Ma S, Lin M, Hu Y, Liang J, Song Y, Li W and Zhao T
Phthalates are widely used plasticizers that can leach from consumer products and pose potential health risks, particularly to infants whose developing systems are vulnerable to environmental toxicants. While various exposure pathways have been identified, the contribution of dermal absorption from disposable diapers remains inadequately characterized. This study recruited 66 infants from Guangzhou, a representative city in southern China. Paired disposable diaper and urine samples were collected from each participant. Six phthalates in the diapers and nine metabolites in the urine were quantitatively analyzed. The predominant phthalate detected in the diapers was bis-2-ethylhexyl phthalate (DEHP, with a median concentration of 1670 ng/g, range: 678-5200 ng/g), followed by di-n-butyl phthalate (DnBP, 948 ng/g, range: 189-5980 ng/g), di-iso-butyl phthalate (DiBP, 333 ng/g, range: 16.1-4910 ng/g), and diethyl phthalate (DEP, 252 ng/g, range: 116-3350 ng/g). In urine, metabolites of DEHP (mEHP, mEHHP, and mEOHP) were the most abundant (87.1 ng/mL), followed by mnBP (metabolites of DnBP, 44.6 ng/mL), mEP (metabolites of DEP, 33.7 ng/mL), and miBP (metabolites of DiBP, 13.9 ng/mL). A positive correlation was observed between DnBP levels in diapers and mnBP levels in urine (r = 0.259, = 0.035). Additionally, several urinary metabolites (miBP, mnBP, and mEP) were positively associated with a biomarker of DNA oxidative damage, 8-hydroxydeoxyguanosine (r = 0.265-0.316, < 0.01). The estimated daily uptake of DEP, DiBP, DnBP, and DEHP through dermal absorption from diapers accounted for 44.9%, 19.5%, 15.1%, and 7.76% of total exposure to these phthalates, respectively. These findings suggest that dermal absorption from diapers is a significant exposure pathway for infants. Given that both the amount of exposure and the contribution of dermal uptake are higher in younger infants, further attention is warranted to understand the potential effects of transdermal phthalate exposure on infant growth and development.
Safety Profile and Hepatotoxicity of Anaplastic Lymphoma Kinase Tyrosine Kinase Inhibitors: A Disproportionality Analysis Based on FDA Adverse Event Reporting System Database
Yang Y, Tan S, Pu Y and Zhang J
Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) have become first-line therapies for advanced non-small cell lung cancer (NSCLC) with ALK rearrangements. This study investigates ALK-TKI-associated adverse events (AEs), focusing on identifying hepatotoxicity signals and previously undocumented safety concerns. Using disproportionality analysis of 56,864 reports from the FDA Adverse Event Reporting System (FAERS) database, we systematically classified AEs via the Medical Dictionary for Regulatory Activities (MedDRA). At the System Organ Class (SOC) level, crizotinib exhibited a significantly stronger signal for eye disorders, ceritinib was uniquely linked to gastrointestinal disorders, and loratinib was predominantly associated with metabolism and nutrition disorders. Several AEs previously undocumented in drug labels were identified, including pericardial effusion, elevated C-reactive protein, hemolytic anemia, hemoptysis, and decreased hemoglobin. Furthermore, crizotinib, ceritinib, and alectinib were significantly associated with hepatotoxicity, marked by elevated alanine aminotransferase, aspartate aminotransferase, and hepatic enzyme levels. These findings highlight the need for vigilant monitoring of unlabeled AEs and potential label updates, particularly for hepatotoxicity risks associated with crizotinib, ceritinib, and alectinib.
A Quantitative and Comparative Study of Heroin-Related Metabolites in Different Postmortem Fluids and Tissues
Zughaibi TA, Assiri Z, Mirza A, Alharbi H, Alzahrani AE, Alahmadi SA, Alsolami F, Al-Saadi A, Almoustady M, Al-Zahrani S, Altowairqi M and Al-Asmari AI
This study assessed and compared the postmortem concentrations of 6-monoacetylmorphine [6-MAM] and 6-acetylcodeine [6-AC], morphine, and codeine in various tissues and fluids from 52 postmortem cases related to heroin use. Samples were received at the Poison Control and Forensic Chemistry Center in Jeddah, Saudi Arabia, and analyzed using liquid chromatography-mass spectrometry. Descriptive and inferential statistics, including median, range, variability, and outliers, were used for analysis. The results showed significant variability in heroin and metabolite concentrations across different fluids and tissues. Tissue specimens were analyzed in 38 cases (73%), with 50% of cases exhibiting putrefaction. Blood and tissue samples were available in 39 cases, highlighting the need for alternative specimens in challenging cases. Notably, heroin metabolites were detected in unique matrices, such as nasal swabs, bladder tissues, lung tissues, and small intestine tissues, underscoring the potential of these samples in forensic investigations, especially when traditional bodily fluids are unavailable or compromised. These findings suggest that environmental factors, timing of substance use, and postmortem changes influence substance distribution, emphasizing the need to consider the location of death when interpreting toxicological results for accurate forensic analysis. This study provides valuable insights into the distribution, correlation, and significance of heroin and its metabolites in postmortem samples, aiding the confirmation of heroin overdose. These findings contribute to the limited data on postmortem cases in the Middle East and North Africa, particularly Saudi Arabia, supporting efforts to curb drug abuse in this region. This knowledge can inform public health strategies and forensic practices, ultimately aiding efforts to address and mitigate drug abuse.
Acrylamide and Its Metabolite Glycidamide Induce Reproductive Toxicity During In Vitro Maturation of Bovine Oocytes
El-Sheikh M, Mesalam AA, Mesalam A and Kong IK
Acrylamide (ACR) and its metabolite glycidamide (GLY) are contaminants with known toxic effects, especially in reproductive systems. However, the mechanisms underlying their embryotoxic effects remain inadequately understood. In the current study, we investigated the effects of ACR and GLY exposure on oocyte and embryo developmental competence, focusing on DNA damage, apoptosis, autophagy, and epigenetic regulation. Oocytes were exposed to varying concentrations of ACR and GLY during in vitro maturation. The results demonstrated that both ACR and GLY significantly reduced cleavage and blastocyst developmental rates in a dose-dependent manner. Consequently, treated oocytes exhibited actin organization disruption, increased DNA damage, and heightened apoptosis compared to the control. Autophagy-related markers, including LC3A, LC3B, and ATG7, were significantly elevated in the treatment groups. Moreover, both ACR and GLY compounds altered the expression of the epigenetic and MAPK signaling pathway regulators, such as DPPA3, EZH1, EZH2, EED, DUSP1, and ASK1. These disruptions collectively impaired embryonic development. This study underscores the adverse effects of ACR and GLY on reproductive health, driven by oxidative stress, genotoxicity, dysregulated autophagy, and epigenetic alterations.
Serum Concentrations of Fipronil and Metabolites in Japanese Pregnant Women: Relationship with Thyroid Hormone Levels
Ikeda K, Hisada A, Otake T, Omagari R, Nakajima D, Kato N and Yoshinaga J
Fipronil, a widely used phenylpyrazole insecticide, is known to disrupt circulating thyroid hormone (TH) levels in rodents. Concentrations of fipronil and its metabolites (fipronil sulfone and fipronil sulfide) in serum samples collected in 2009-2011 were measured for 131 Japanese pregnant women by a sensitive and accurate liquid chromatography-tandem mass spectrometric method developed in our laboratory to relate TH levels. Fipronil sulfone was detected in all the subjects with the median being 21 ng/L (min-max: 6.8-89), but fipronil and fipronil sulfide were detected in none of the subjects (detection limit: 5.0 and 1.2 ng/L, respectively), indicating a rapid and exclusive oxidative conversion to fipronil sulfone upon exposure. The median concentration of fipronil sulfone was lower than those previously reported for general populations in other countries by one order of magnitude. There were no attributes or dietary habits of the subjects that significantly vary the serum fipronil sulfone concentrations. Multiple regression analyses found no significant association between serum concentrations of fipronil sulfone and free thyroxine- or thyroid-stimulating hormone levels, indicating the absence of adverse effects on circulating TH levels probably due to the lower exposure levels of the present subjects. The present result would be valuable for establishing a dose-effect relationship of fipronils in humans on population levels.
Progestin Pollution in Surface Waters of a Major Southwestern European Estuary: The Douro River Estuary (Iberian Peninsula)
Silva F, Alves RF, Rocha E and Rocha MJ
The concentrations and spreading of eight synthetic and two natural progestins (PGs) were investigated in surface waters from ten sites at the Douro River Estuary. Samples were filtrated and subjected to solid-phase extraction (SPE) to isolate and concentrate the target PGs. The extracts were cleaned by silica cartridges and analyzed by LC-MS/MS. The finding of biologically relevant amounts of gonanes (22.3 ± 2.7 ng/L), progesterone derivatives (12.2 ± 0.5 ng/L), drospirenone (4.1 ± 0.8 ng/L), and natural PGs (9.4 ± 0.9 ng/L) support the possibility of these compounds acting as endocrine disruptors. Despite the absence of significant differences amongst sampling sites and seasons, the principal component analysis (PCA) and the linear discriminant analysis (LDA) approaches reveal that spring and summer have different patterns of PG distribution compared to autumn and winter. The assessment of risk coefficients () and the potential concentrations of synthetic progestins in fish blood sustains that all tested compounds pose a significant risk to local biota ( > 1). Additionally, three progestins-norethindrone, norethindrone acetate, and medroxyprogesterone acetate-should reach human-equivalent therapeutic levels in fish plasma. Overall, the current data show PGs' presence and potential impacts in one of the most important estuaries of the Iberian Peninsula.
Developmental Toxicity of Micro(Nano)Plastics (MNPs) Exposure in Mammals: A Mini-Review
Xia G, Wan T, Chen Z, Liu C and Li R
Micro(nano)plastics (MNPs) pose a significant threat to both ecological environments and human health. This review systematically examines the developmental toxicity of MNPs in mammals, with a particular focus on the impact of maternal and paternal exposure on offspring. Evidence indicates that MNPs can cross placental barriers, inducing abnormal development of embryos, fetuses, and placentas. This disruption leads to a range of adverse outcomes, including neurodevelopmental abnormalities, behavioral disorders, reproductive system damage, etc., in offspring. Through a comprehensive analysis of the existing literature, this review aims to provide a foundation for future research on the developmental toxicity of MNPs and highlight the urgent need for action to mitigate the detrimental effects of MNPs on human health and ecosystem integrity.
The Influence of Meteorological Conditions and Seasons on Surface Ozone in Chonburi, Thailand
Kawichai S, Kliengchuay W, Aung HW, Niampradit S, Mingkhwan R, Niemmanee T, Srimanus W, Phonphan W, Suwanmanee S and Tantrakarnapa K
This study aims to examine the relationship between meteorological factors, specifically temperature, solar radiation, and ozone concentration levels. Levels of surface ozone were monitored (O) in Chonburi, Thailand (located at 3.2017° N, 101.2524° E), from January 2010 to December 2020. Thailand's coastal tropical environment provided a unique setting for the study. The study revealed a distinctive seasonal trend in ozone levels, with the highest concentrations occurring during the winter and the lowest in the rainy season, on average. The increase of O in the summer was primarily attributed to intense ground-level solar radiation and higher temperatures of around 30-35 °C, enhancing O concentrations ranging from 200 to 1400. During the winter, there is an increased elimination of the O concentration by higher levels of NO. The study also examined the relationship between ozone levels and various meteorological factors to identify which had the most significant impact on ozone formation. The analysis showed that the ozone concentration has a strong negative correlation with relative humidity but is positively correlated with solar radiation, temperature, and wind speed.
Mesoplastics: A Review of Contamination Status, Analytical Methods, Pollution Sources, Potential Risks, and Future Perspectives of an Emerging Global Environmental Pollutant
Ellos DMC, Chien MF, Inoue C, Nakano H, Isobe A, Onda DFL, Watanabe K and Bacosa HP
Mesoplastics are emerging environmental pollutants that can pose a threat to the environment. Researching mesoplastics is crucial as they bridge the gap between macroplastics and microplastics by determining their role in plastic fragmentation and pathways, as well as their ecological impact. Investigating mesoplastic sources will help develop targeted policies and mitigation strategies to address plastic pollution. These pollutants are found across aquatic, terrestrial, and agricultural ecosystems. Unlike microplastics, mesoplastics are reviewed in the scientific literature. This paper focuses on existing published research on mesoplastics, determining the trends and synthesizing key findings related to mesoplastic pollution. Research primarily focused on marine and freshwater ecosystems, with surface water and beach sediments being the most studied compartments. Mesoplastics research often offers baseline data, with increased publications from 2014 to 2024, particularly in East Asia. However, certain ecosystems and regions remain underrepresented. Also, mesoplastics can disrupt ecosystems by degrading biodiversity, contaminating soils and waters, and affecting food chains. Mesoplastics can also become vectors for additives and pathogenic microorganisms, highlighting their environmental risks. Various factors influence mesoplastics' prevalence, including anthropogenic and non-anthropogenic activities. With this, future research should expand into less-studied ecosystems and regions, explore mesoplastic interactions with pollutants and organisms, and promote public awareness, education, and policy measures to reduce plastic use and mitigate pollution globally.
A Review on Flame Retardants in Soils: Occurrence, Environmental Impact, Health Risks, Remediation Strategies, and Future Perspectives
Thuy TL, Hoang TD, Hoang VH and Nguyen MK
As novel pollutants, flame retardants (FRs) are prone to accumulating in soil and might increase human health risks. It is advisable to emphasize the biomagnification of FRs within the terrestrial food chain, particularly concerning mammals occupying higher trophic levels. Exposure to soil particles laden with FRs may result in numerous health complications. These findings offer significant insights into FR pollutant profiles, tracing origins and recognizing health risks associated with soil samples. Reports have revealed that exposure to FRs can pose serious health risks, including neurodevelopmental impairments, endocrine system disruption, and an increased likelihood of cancer. Nanomaterials, with their high surface area and flexible properties, possess the ability to utilize light for catalytic reactions. This unique capability allows them to effectively degrade harmful contaminants, such as FRs, in soil. Additionally, biological degradation, driven by microorganisms, offers a sustainable method for breaking down these pollutants, providing an eco-friendly approach to soil remediation. These approaches, combined with optimum remediation strategies, hold great potential for effectively addressing soil contamination in the future. Further research should prioritize several key areas, including ecological behavior, contaminant monitoring, biological metabolomics, toxicity evaluation, and ecological impact assessment.
Arsenic Exposure During Pregnancy and Childhood: Factors Explaining Changes over a Decade
Rubilar P, Hirmas-Adauy M, Apablaza M, Awad C, Molina X, Muñoz MP, Delgado I, Zanetta-Colombo NC, Castillo-Laborde C, Matute MI, Retamal MA, Olea A, Pino P, González C, Carvajal C and Iglesias V
Arsenic chronic exposure, particularly in its inorganic form, represents a significant public health concern. This study was conducted in Arica, the northernmost city in the country, whose inhabitants have been exposed to inorganic arsenic both naturally through drinking water and anthropogenically due to a toxic waste disposal site. We explored changes in inorganic arsenic levels in a cohort of pregnant women and their children over a decade, identifying exposure trends and their determinants. We used data on arsenic exposure through maternal urine samples during pregnancy, collected by the Health Authority between 2013 and 2016 (measurement 1), and followed up with assessments of their children in 2023 (measurement 2). Temporal changes in inorganic arsenic concentration were analyzed using the Wilcoxon Signed-Rank test, and a mixed linear regression model was employed to determine which factors contributed to urinary inorganic arsenic levels. We did not observe significant differences in mean arsenic concentrations between the two-time points ( = 0.4026). The mixed linear regression model revealed that children consuming bottled water had 8.3% lower urinary inorganic arsenic concentrations than those drinking tap water (95% CI: -15.36 to -0.54%). Additionally, children from ethnic groups had 8.64% higher inorganic arsenic concentrations (95% CI: 0.49 to 17.5%), while those with caregivers with higher education showed a 13.67% reduction (95% CI: -25.06 to -0.56%). Despite mitigation efforts, these findings underscore the ongoing risk of inorganic arsenic exposure among vulnerable populations. They further emphasize the importance of addressing natural arsenic contamination in water and implementing targeted interventions to reduce disparities associated with socioeconomic and demographic factors.
Phthalates and Non-Phthalate Plasticizers and Thyroid Dysfunction: Current Evidence and Novel Strategies to Reduce Their Spread in Food Industry and Environment
Gorini F, Tonacci A, Sanmartin C and Venturi F
Thyroid hormones (THs) play a crucial role in various biological functions, including metabolism, cell growth, and nervous system development, and any alteration involving the structure of the thyroid gland and TH secretion may result in thyroid disease. Growing evidence suggests that phthalate plasticizers, which are commonly used in a wide range of products (e.g., food packaging materials, children's toys, cosmetics, medical devices), can impact thyroid function, primarily affecting serum levels of THs and TH-related gene expression. Like phthalate compounds, recently introduced alternative plasticizers can leach from their source material into the environment, particularly into foods, although so far only a very limited number of studies have investigated their thyroid toxicity. This review aimed at summarizing the current knowledge on the role of phthalate and non-phthalate plasticizers in thyroid dysfunction and disease, describing the major biological mechanisms underlying this relationship. We will also focus on the food industry as one of the main players for the massive spread of such compounds in the human body, in turn conveyed by edible compounds. Given the increasing worldwide use of plasticizers and the essential role of THs in humans, novel strategies should be envisaged to reduce this burden on the thyroid and, in general, on human health.
The Association Between Per- and Polyfluoroalkyl Substances Exposure and Thyroid Hormones in Men and Non-Pregnant Women: A Systematic Review and Meta-Analysis
Zhang B, Zhao M, Cong X, Liu C, Li C, Qiu Y, Li S, Chen Y, Li X and Li P
Studies have shown that per- and polyfluoroalkyl substances (PFAS) may impact thyroid function in human health. While the consistency between PFAS exposure and thyroid health effects in pregnant women has been validated, the effects on men and non-pregnant women remains inconclusive. To address this, a meta-analysis was carried out in this paper, with 14 eligible studies retrieved from Embase, PubMed, and Web of Science that were published up to 2 June 2024, focusing on the relationship between PFAS exposure and its effect on thyroid hormone levels in the human body. The thyroid function indexes analyzed included thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4). The estimated value (β) and the corresponding confidence interval (95% CI) were extracted from the literature. A heterogeneity test was carried out, and the sensitivity analysis and publication bias of the studies were analyzed using Stata 18.0. The results revealed that in men and non-pregnant women, PFOA was positively correlated with FT3 (β = 0.011, 95% CI = 0.001, 0.02, I = 13.4). However, no significant associations were found between exposure to other PFAS and thyroid hormones. A subgroup analysis further indicated that the correlations between PFAS exposure and thyroid hormone levels were more significant in adolescents, in both America and Europe.
Impact of a Nanoscale Iron-Chlorobenzene Mixture on Pulmonary Injury in Rat Pups: Extending Exposure Knowledge Using Network Technology
Liu K, Xu Y, Ying M and Chen M
Particulate matter coexists with persistent organic pollutants (POPs) in the atmosphere, which can enter the human body by accompanying inhalable particles in the respiratory tract. Photochemical conversion further alters the chemical composition of the precursor particles and secondary products. This study investigated the effects of nanoscale iron-chlorobenzene mixtures and their photochemical conversion products on early lung development in rat pups. Using network toxicology and animal experiments, we constructed a compound toxicity-target network and developed air exposure models. This study revealed that both pollutants, before and after photochemical conversion, bound to the aryl hydrocarbon receptor (AhR), increased oxidative stress, altered lung tissue morphology, and reduce inflammatory factor expression. Rat pups were highly sensitive to pollutants during critical stages of lung development. However, no significant differences in oxidative stress or inflammation were observed between the pollutants, likely because of immature lung tissues. Once tissue damage reached a threshold, the response to increasing pollutant concentrations diminished. This study provides insights into atmospheric pollutant toxicity and scientific evidence for the risk assessment of dioxin-like nanoscale mixtures.
Optimization of Illuminance and Color-Temperature Conditions for Railway Passengers' Comfort Based on Oxygenated Hemoglobin Saturation in the Brain
Kim M, Lee J, Lee Y and Park D
Railway travel is an eco-friendly means of transportation, and passengers are spending increasing amounts of time on trains while engaging in various activities. As a major factor affecting railway passengers' comfort, we investigated the effects of lighting. Korean train cars are required to have two rows of light-emitting diode lights with a minimum illuminance of 500 lx, so we examined changes in cerebral blood flow under various illuminance conditions around this threshold value. We used functional near-infrared spectroscopy to measure prefrontal cortex activation in 29 college students under illuminance values of 300, 500, and 800 lx and color-temperature values of 2700 K (bulb color), 4000 K (white color), and 5500 K (blue color). Mean brain activity values were compared using analysis of variance. Of the 48 channels, significant interaction effects between color and illuminance on brain activation responses were observed for channel 38, as well as in the right dorsolateral prefrontal cortex among the different brain regions of the Brodmann area ( < 0.05). Oxygenated hemoglobin concentrations had consistently negative values for all the treatment combinations, and individual treatment analyses based on single-sample Student's -tests showed different degrees of brain activation among channels and Brodmann areas. Meanwhile, a comparison of absolute values indicated that an illuminance level of 500 lx was more comfortable than levels of 300 and 800 lx, and that white color was more comfortable than bulb color and blue color. These results provide a scientific basis for the design of train cars that improve passenger comfort and satisfaction, which is anticipated to enhance the quality of railway services.
Atmospheric Heavy Metal Pollution Characteristics and Health Risk Assessment Across Various Type of Cities in China
Cha Z, Zhang X, Zhang K, Zhou G, Gao J, Sun S, Gao Y and Liu H
This study investigates the spatiotemporal trends and health risks of nine atmospheric heavy metals (Pb, As, Mn, Ni, Cr, Cd, Zn, Cu, Fe) in PM across 50 Chinse cities, comparing resource-industrial cities (RICs) and general cities (GCs) before (2014-2018) and after (2019-2021) China's 2018 Air Pollution Prevention and Control Action Plan. Post-2018, concentrations of all metals except Fe declined significantly (33-77%), surpassing PM reductions (25%). Geospatial analysis revealed elevated heavy metal levels in northern and southern regions in China, aligning with industrial and mining hotspots. While RICs exhibited persistently higher metal concentrations than GCs, the inter-city gap narrowed post-2018, with RICs achieving greater reduction. Pre-2018, the combined non-carcinogenic hazard index (HI < 1) remained below safety thresholds, but the combined carcinogenic risk total (CRT) for children exceeded 10, driven primarily by As and Cr(VI). HIs were 1.5-2.0 times higher in RICs than in GCs. Post-2018, the CRT declined by 69.0-71.1%, aligning with reduced heavy metal levels. Despite improvements, CRTs necessitate targeted mitigation for As (contributing 81.1-86.2% to CRT) and Cr(VI) (11.7-14.0%). These findings validate the policy's effectiveness in curbing industrial and vehicular emissions but underscore the need for metal-specific controls in resource-intensive regions to safeguard child health.
Evaluation of Leaching Characteristics of Heavy Metal Ions from Red Mud-Graphite Tailings
Li K, Lu X, Jiang C, Wang D, Zhu J, Xu M, Zhang L and Cheng X
The rapid growth of aluminum and graphite industries has generated substantial stockpiles of red mud and graphite tailings, which pose environmental risks due to their high heavy metal content and potential for soil and water contamination. This study investigated the leaching behavior of heavy metals from these materials post-stabilization using cement and a sulfonated oil-based ion curing agent, thereby evaluating their suitability for safe reuse. Semi-dynamic leaching experiments were employed to measure heavy metal release, supplemented by kinetic modeling to discern key leaching mechanisms. The findings indicated that the heavy metal concentrations in leachates were consistently below regulatory standards, with leaching dynamics influenced by dual mechanisms: the diffusion of ions and surface chemical reactions. A diffusion coefficient-based analysis further suggested low leachability indices for all metals, confirming effective immobilization. These results suggest that cement and curing agent-stabilized red mud-graphite tailing composites reduce environmental risks and possess characteristics favorable for resource recovery, thus supporting their sustainable use in industrial applications.
Development of a Treatment System of Water with Cr (VI) Through Models Using Biomass with Iron Chloride
Sayago UFC, Ballesteros VB and Lozano AM
In the context of critical water quality issues, there is a pressing need for more pragmatic approaches to water research. Adsorbent biomass, derived from abundant and effective natural sources, holds considerable promise as a solution. , a type of plant biomass, has emerged as a particularly promising material due to its high adsorption capacity. When combined with iron chloride, this capacity is significantly enhanced, and the addition of EDTA is essential for the reuse of treated water. The economic viability of this material in water treatment has been thoroughly evaluated, and the project was developed with the aim of building treatment systems using biomass in conjunction with iron chloride. The development process involved the creation of a special material composed of 85% dried and ground and 15% iron chloride. The process was scaled up with the most effective biomass for treatment and subsequent elutions with EDTA. The outlet conditions, the quantity of pollutant removed, and the treated volume were established, and subsequently the extraparticle diffusion constant Kf, the intraparticle diffusion constant, and the characteristic isotherm were determined. The identification of the intraparticle diffusion model, Ks, was made possible by the results of the model, which indicated the specific route for the construction of a pilot-scale treatment system. The pilot-scale prototype was constructed using 1000 g of EC (2) of biomass (850 g of and 150 g of chloride of iron). The prototype developed in the present investigation could be used to treat effluents contaminated with heavy metals, especially chromium, and is an advanced environmental research project that contributes to the improvement of water quality.