Toxics最新文献

Flight line personnel are constantly exposed to noise and jet fuel while working on flight lines. Studies suggest that jet fuel in combination with noise affects hearing loss more than noise exposure alone. This study examined the combined effects of jet fuel and noise exposure on the hearing of flight line personnel stationed at Japan Air Self-Defense Force Air Bases (Hamamatsu, Matsushima, Hyakuri, Yokota, and Iruma) and US Air Force Air Bases (Kadena and Misawa) in Japan. Samples were collected from all participants, 97 flightline-exposed and 71 control volunteers, to measure their individual noise levels with a personal sound level meter and volatile organic chemicals (VOCs) with a chemical sampling pump during a single shift. Blood samples were collected post shift. Urine samples (entire void) were collected prior to the shift (morning first void) and post shift. VOCs were measured in air, blood, and urine. An audiometric test battery, consisting of immittance measurements, audiograms, distortion product otoacoustic emissions, and the auditory brain response, was conducted after the shift to examine the hearing of participants. Total VOCs in personal air samples were in the ppb range for each group. Tinnitus and temporary hearing loss were reported in audiological histories but were also present in some controls. Noise levels on the flight line were greater than the action level for requiring hearing protection and exceeded exposure limits, but all exposed subjects reported wearing hearing protection. Audiometric tests identified significant differences and trends between flight line and control personnel, indicating the potential for hearing disorders. In spite of very low levels of VOC exposure and wearing hearing protection for noise, there is still the potential for hearing issues in flight line personnel.

Emerging contaminants refer to chemical substances that have not been widely regulated but possess the potential to cause adverse effects on both the environment and human health. Antibiotics, as emerging contaminants, pose significant threats to ecosystems and human health due to their widespread use and persistence in the environment. Levofloxacin, a broad-spectrum fluoroquinolone antibiotic, is commonly employed in the treatment of bacterial infections, and has been frequently detected in environmental matrices and freshwater systems. In this study, we assessed the effects of levofloxacin on hatchability, mortality rates, malformations, behavioral changes, and cardiac development in zebrafish embryos by exposing them to varying concentrations of levofloxacin (0, 0.5, 1, 2, 4, and 8 mM). Our results demonstrate that levofloxacin exposure significantly impaired the growth and development of zebrafish larvae, particularly at higher concentrations. Notable effects included reduced body length, abnormal yolk sac and swim bladder development, pericardial edema, prolonged distances between the sinus venosus and arteriolar bulb (SV-BA), and disruptions in heart rate. Quantitative PCR analysis further revealed that levofloxacin exposure significantly upregulated the expression of key cardiac development genes in zebrafish larvae, including nppa, myh6, cacna1ab, myl7, gata4, nkx2.5, tbx2b, and tbx5b. These findings indicate that levofloxacin exposure exerts significant toxic effects on both embryonic and larval growth as well as heart development and gene expression in zebrafish. This study provides critical insights into the potential ecological risks posed by levofloxacin along with other antibiotics while laying a foundation for further investigation into their toxicological mechanisms.

The mechanisms driving changes in the stability of phosphorus (P) in sediments under lake ecosystem degradation remain poorly understood. This study investigated the P-binding forms in sediments from three plateau lakes with different trophic states in Yunnan Province, China, aiming to elucidate the responses of sediment P compositions to human activities, lake trophic status, and dissolved organic matter (DOM) characteristics. The results showed that human activity directly contributed to sediment P retention. The trophic type of lake exerted a discernible effect on P mobility in the sediments, as eutrophic algae-type lakes had a higher content of sediment mobile-P. Moreover, the sediment DOM promoted the adsorption of BD-P and NH₄Cl-P. Generally, exogenous pollution caused by human activity leads to lake eutrophication and a decline in lake ecosystem stability. This variation was largely influenced by water depth. A decrease in lake ecosystem stability leads to increased P mobility in sediments, which increases the risk of endogenous pollution. The DOM plays an important role in the mobility of sediment P. These insights offer a novel perspective for understanding how lake ecosystem characteristics are related to endogenous P loads in lakes.

PM_2.5 is fine particulate matter with a diameter of less than 2.5 μm. Recent evidence has shown that exposure to PM_2.5 markedly elevates the risk of neurodegenerative diseases, neurodevelopmental disorders, and cardiovascular diseases, which may culminate in cognitive impairment. Nevertheless, the precise mechanisms through which PM_2.5 affects cognitive function are unclear. Recent studies have demonstrated that PM_2.5-induced epigenetic alterations are associated with the development of cognitive impairment. Epigenetic alterations include modifications to DNA methylation, histone modifications, and non-coding RNAs. The underlying mechanisms of epigenetic alterations are related to inflammation, synaptic dysfunction, cardiovascular factors, and alterations in neuronal structure and function. This review reports the latest findings on the relationship between PM_2.5-induced epigenetic alterations and the development of cognitive disorders, offering novel insights into the cognitive effects of air pollution.

The relationship between ozone (O₃) exposure and gestational diabetes mellitus (GDM) in twin pregnancies remains unexplored. This study aimed to investigate the association between O₃ exposure and GDM risk in twin pregnancies, and to explore the synergistic effects of O₃ exposure with other maternal factors. A total of 428 pregnancies recruited from a prospective twin cohort were included. Cox proportional hazard models with distributed lag non-linear models (DLNMs) were applied to examine the associations between O₃ exposure and the risk of GDM and to identify the critical windows. The multiplicative and additive interaction were further analyzed to test the synergistic effects. A 10 μg/m³ increase in average O₃ exposure during the 12 weeks before pregnancy was associated with a 26% higher risk of GDM. The critical windows were identified in the period from the 3rd week before gestation to the 2nd gestational week as well as from the 17th to 19th gestational week. There were synergistic effects between high O₃ exposure during preconception and advanced maternal age, and a history of preterm birth/abortion/stillbirth. Periconceptional O₃ exposure could increase the risk of GDM in twin pregnancy women, and the synergism of O₃ exposure with certain GDM risk factors was observed.

Contaminants of Emerging Concern (CECs), including per- and polyfluoroalkyl substances (PFASs) and organophosphate flame retardants (OPFRs), have raised global concerns due to their persistence, bioaccumulation potential, and toxicity. This study presents a comprehensive investigation of the occurrence, spatiotemporal distribution, potential sources, and the ecological and human health risks associated with 18 PFASs and 9 OPFRs in the surface waters of the upper Yangtze River, China. The water samples were collected from the main stream and five major tributaries (Min, Jinsha, Tuo, Jialing, and Wu Rivers) in 2022 and 2023. The total concentration of PFASs and OPFRs ranged from 16.07 to 927.19 ng/L, and 17.36 to 190.42 ng/L, respectively, with a consistently higher concentration observed in the main stream compared to the tributaries. Ultra-short-chain PFASs (e.g., TFMS) and halogenated OPFRs (e.g., TCPP) were the predominant compounds, likely originating from industrial discharges, wastewater effluents, and other anthropogenic sources. Ecological risk assessments indicated low-to-moderate risks at most sampling sites, with higher risks near wastewater discharge points. Human health risk evaluations suggested negligible non-carcinogenic risks but identified potential carcinogenic risks from OPFR exposure for adults at specific locations, particularly in Leshan city. This study highlights the importance of understanding the fate and impacts of PFASs and OPFRs in the upper Yangtze River, and provides valuable insights for developing targeted pollution control strategies and risk management measures.

Using NHANES data from 2003 to 2008, 2011 to 2012, and 2015 to 2020, we examined the relationship between urinary organophosphate pesticide (OPP) metabolites and the triglyceride glucose (TyG) index. The TyG index evaluates insulin resistance, a crucial factor in metabolic diseases. Linear regression analyzed urinary metabolites in relation to the TyG index and OPPs. An RCS (restricted cubic spline) model explored the nonlinear relationship of a single OPP metabolite to TyG. A weighted quantile regression and quantile-based g-computation assessed the impact of combined OPP exposure on the TyG index. XGBoost, Random Forest, Support Vector Machines, logistic regression, and SHapley Additive exPlanations models investigated the impact of OPPs on the TyG index and cardiovascular disease. Network toxicology identified CVD targets associated with OPPs. This study included 4429 participants based on specific criteria. Linear regression analysis indicated that diethyl thiophosphate was positively correlated with the TyG index. The positive correlation between OPP metabolites and the TyG index at low to moderate concentrations was confirmed by WQS and QGC analyses. The machine learning results aligned with traditional statistical findings. Network toxicology identified PTGS3, PPARG, HSP40AA1, and CXCL8 as targets influenced by OPPs. OPP exposure influences IR and cardiometabolic health, highlighting the importance of public health prevention.

Environmental toxins and epigenetic changes have been linked to neurodegenerative diseases, including Alzheimer's Disease (AD), Parkinson's Disease (PD), and amyotrophic lateral sclerosis (ALS). This paper aimed to (i) identify environmental toxins associated with AD, PD, and ALS, (ii) locate potential industrial sources of toxins in the United States (U.S.), and (iii) assess epigenetic changes driven by exposure to toxins reported by patients. Environmental factors and epigenetic biomarkers of neurodegeneration were compiled from 69 studies in the literature using Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) and geographic information system approaches. Some 127 environmental toxins have been associated or putatively associated with AD, PD, or ALS, with four toxic metals (As, Cd, Mn, and Hg) common to all three of these neurodegenerative diseases. Environmental toxins associated with epigenetic changes (e.g., DNA methylation) in patients include air pollutants, metals, and organic chemicals (e.g., pesticides, mycotoxins, and cyanotoxins). Geographic analysis showed that study locations (e.g., U.S., Europe, and East Asia) were selected by researchers based on convenience of access rather than exposure risk and disease prevalence. We conclude that several toxins and epigenetic markers shared among neurodegenerative diseases could serve as attractive future targets guiding environmental quality improvements and aiding in early disease detection.

Ethephon (2-chloroethylphosphonic acid) is a generally used plant growth regulator, but the data on its toxic effects, especially in humans, are very limited. This study was conducted to describe the clinical characteristics, management, and outcomes of patients exposed to products containing ethephon. We performed an 8-year retrospective study using data from the Ramathibodi Poison Center database (2013-2020), which included 252 patients. Most patients were male, with a median age of 32 years. Almost all patients were exposed through ingestion, mainly in unintentional circumstances. The clinical presentations included local effects, gastrointestinal (GI), neurological, and respiratory symptoms. Some patients required hospital admission; specifically, seven patients received inotropic drugs, and six were intubated with ventilator support. Most patients had either no or only minor clinical effects. However, six patients experienced moderate/severe effects, and two patients died. Age, intentional exposure, and the presence of initial neurological symptoms could prognosticate moderate to fatal outcomes. In conclusion, exposure to ethephon predominantly resulted in no or minor effects, and GI symptoms were the most common clinical manifestation. The cholinergic toxic syndrome was not frequently observed. The mortality rate was very low. Patients presenting with factors associated with worse outcomes should be monitored closely for clinical deterioration and appropriately managed.

Environmental particulate matter (PM) exposure has been widely recognized for its significant adverse effects on human health. Monitoring PM levels is one of the essential parameters of air quality assessment. However, PM mass concentration alone does not sufficiently explain its toxicological impacts and effects on health. This study highlights the importance of oxidative potential (OP) as a promising metric for evaluating PM toxicity. It focuses on standardizing the dithiothreitol (DTT) assay as a tool for OP measurement. In order to investigate the impact of various extraction techniques, reagent concentrations, and assay conditions, four previously established protocols were tested without modification, while a novel protocol was introduced based on an extensive literature review. Results revealed strong positive correlations between the new and most established protocols. These findings highlight the significance of the new protocol in advancing the development of standardized methodologies for applying the DTT assay and demonstrating its reliability and relevance. While developing a standardized DTT assay involves addressing numerous parameters-from filter extraction to assay application-this research provides a solid base for achieving consistency in OP measurements and overcoming this critical issue.