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Toxics, Volume 12, Issue 3 (March 2024) – 68 articles

Cover Story (view full-size image): Despite firefighting being classified as carcinogenic to humans, the underlying biological mechanisms have yet to be fully understood. Comprehending firefighters’ occupational exposure across various settings and time points of their activity is crucial. We characterized firefighters’ occupational exposure to particulate matter in fire stations prior to the wildfire season in the Northern region of Portugal. The biological impact of estimated inhaled doses of PM10 and PM2.5 (indoor/outdoor) was accessed through buccal micronucleus cytome assay in exfoliated buccal cells. Our findings provide the essential baseline for further studies assessing exposure during the wildfire season, highlighting the importance of biomonitoring programs to identify individuals predisposed to adverse health outcomes. View this paper
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12 pages, 2915 KiB  
Article
Electrospinning Chitosan/Fe-Mn Nanofibrous Composite for Efficient and Rapid Removal of Arsenite from Water
by Lingli Min, Yahui Ma, Bi Zhang, Dulan He, Jinhua Chen, Xuerong Li, Shuhua Wang and Yulang Chi
Toxics 2024, 12(3), 230; https://doi.org/10.3390/toxics12030230 - 21 Mar 2024
Viewed by 736
Abstract
Efficient removal of extremely mobile and toxic As(III) from water is a challenging but critical task. Herein, we developed a functionalized sorbent of chitosan nanofiber with iron–manganese (Fe-Mn@CS NF) using a one-step hybrid electrospinning approach to remove trace As(III) from water. Batch adsorption [...] Read more.
Efficient removal of extremely mobile and toxic As(III) from water is a challenging but critical task. Herein, we developed a functionalized sorbent of chitosan nanofiber with iron–manganese (Fe-Mn@CS NF) using a one-step hybrid electrospinning approach to remove trace As(III) from water. Batch adsorption studies were performed to determine the adsorption efficiency under a variety of conditions, including contact time, starting concentration of As(III), ionic strength, and the presence of competing anions. The experimental results demonstrated that the concentration of As(III) dropped from 550 to less than 1.2 µg/L when using 0.5 g/L Fe-Mn@CS NF. This demonstrates the exceptional adsorption efficiency (99.8%) of Fe-Mn@CS NF for removing As(III) at pH 6.5. The kinetic tests revealed that the adsorption equilibrium was reached in 2.6 h, indicating a quick uptake of As(III). The ionic strength effect analysis showed that the adsorbed As(III) formed inner-sphere surface complexes with Fe-Mn@CS NF. The presence of SO42− or F had a negligible impact on As(III) uptake, while the presence of PO43− impeded As(III) absorption by competing for adsorption sites. The exhausted sorbent could be effectively regenerated with a dilute NaOH solution. Even after 10 cycles of regenerating Fe-Mn@CS NF, the adsorption efficiency of As(III) in natural groundwater was maintained over 65%. XPS and FTIR analyses show that the presence of M–OH and C–O groups on the sorbent surface is essential for removing As(III) from water. Overall, our study highlights the significant potential of Fe-Mn@CS NF for the efficient and quick elimination of As(III) from water. Full article
(This article belongs to the Section Toxicity Reduction and Environmental Remediation)
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17 pages, 21149 KiB  
Article
Identifying the Local Influencing Factors of Arsenic Concentration in Suburban Soil: A Multiscale Geographically Weighted Regression Approach
by Yuanli Zhu, Bo Liu, Gui Jin, Zihao Wu and Dongyan Wang
Toxics 2024, 12(3), 229; https://doi.org/10.3390/toxics12030229 - 21 Mar 2024
Viewed by 578
Abstract
Exploring the local influencing factors and sources of soil arsenic (As) is crucial for reducing As pollution, protecting soil ecology, and ensuring human health. Based on geographically weighted regression (GWR), multiscale GWR (MGWR) considers the different influence ranges of explanatory variables and thus [...] Read more.
Exploring the local influencing factors and sources of soil arsenic (As) is crucial for reducing As pollution, protecting soil ecology, and ensuring human health. Based on geographically weighted regression (GWR), multiscale GWR (MGWR) considers the different influence ranges of explanatory variables and thus adopts an adaptative bandwidth. It is an effective model in many fields but has not been used in exploring local influencing factors and sources of As. Therefore, using 200 samples collected from the northeastern black soil zone of China, this study examined the effectiveness of MGWR, revealed the spatial non-stationary relationship between As and environmental variables, and determined the local impact factors and pollution sources of As. The results showed that 49% of the samples had arsenic content exceeding the background value, and these samples were mainly distributed in the central and southern parts of the region. MGWR outperformed GWR with the adaptative bandwidth, with a lower Moran’s I of residuals and a higher R2 (0.559). The MGWR model revealed the spatially heterogeneous relationship between As and explanatory variables. Specifically, the road density and total nitrogen, clay, and silt contents were the primary or secondary influencing factors at most points. The distance from an industrial enterprise was the secondary influencing factor at only a few points. The main pollution sources of As were thus inferred as traffic and fertilizer, and industrial emissions were also included in the southern region. These findings highlight the importance of considering adaptative bandwidths for independent variables and demonstrate the effectiveness of MGWR in exploring local sources of soil pollutants. Full article
(This article belongs to the Section Metals and Radioactive Substances)
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15 pages, 1609 KiB  
Article
Investigation of the Association between Air Pollution and Non-Alcoholic Fatty Liver Disease in the European Population: A Mendelian Randomization Study
by Jing Yang, Yaqi Zhang, Yin Yuan, Zhongyang Xie and Lanjuan Li
Toxics 2024, 12(3), 228; https://doi.org/10.3390/toxics12030228 - 21 Mar 2024
Viewed by 858
Abstract
Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent chronic liver disease worldwide. At the same time, the relationship between air pollution and the likelihood of developing NAFLD has been a subject of debate due to conflicting findings in previous observational research. [...] Read more.
Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent chronic liver disease worldwide. At the same time, the relationship between air pollution and the likelihood of developing NAFLD has been a subject of debate due to conflicting findings in previous observational research. Our objective was to examine the potential correlation between air pollutant levels and the risk of NAFLD in the European population by employing a two-sample Mendelian randomization (MR) analysis. The UK Biobank Consortium provided the summary statistics for various air pollution indicators (PM2.5, PM2.5 absorbance, PM2.5–10, PM10, NO2, and NOx). Additionally, information on NAFLD was obtained from three studies, including one derivation set and two validation sets. Heterogeneity, pleiotropy, and sensitivity analyses were performed under different MR frameworks, and instrumental variables associated with confounders (such as education, smoking, alcohol, and BMI) were detected by tools. In the derivation set, causal relationships between PM2.5, NO2, and NAFLD were observed in univariable Mendelian randomization (UVMR) (Odds Ratio (OR) = 1.99, 95% confidence interval (95% CI) = [1.22–3.22], p = 0.005; OR = 2.08, 95% CI = [1.27–3.40], p = 0.004, respectively). After adjustment for air pollutants or alcohol intake frequency in multivariable Mendelian randomization (MVMR), the above genetic correlations disappeared. In validation sets, the null associations remained in UVMR. Our findings from MR analysis using genetic data did not provide evidence for a causal association between air pollution and NAFLD in the European population. The associations observed in epidemiological studies could be partly attributed to confounders. Full article
(This article belongs to the Special Issue Toxicity and Human Health Assessment of Air Pollutants)
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12 pages, 768 KiB  
Article
Indoor Air Quality and Bioaerosols in Spanish University Classrooms
by Esther Fuentes-Ferragud, Antonio López, Juan Miguel Piera, Vicent Yusà, Salvador Garrigues, Miguel de la Guardia, F. Xavier López Labrador, Marisa Camaró, María Ibáñez and Clara Coscollà
Toxics 2024, 12(3), 227; https://doi.org/10.3390/toxics12030227 - 20 Mar 2024
Viewed by 928
Abstract
A comprehensive study assessed indoor air quality parameters, focusing on relevant air pollutants such as particulate matter (PM10 and PM2.5), gaseous compounds (CO, CO2, formaldehyde, NO2) and volatile/semi-volatile organic chemicals, as well as respiratory viruses (including [...] Read more.
A comprehensive study assessed indoor air quality parameters, focusing on relevant air pollutants such as particulate matter (PM10 and PM2.5), gaseous compounds (CO, CO2, formaldehyde, NO2) and volatile/semi-volatile organic chemicals, as well as respiratory viruses (including SARS-CoV-2), fungi and bacteria in Spanish university classrooms. Non-target screening strategies evaluated the presence of organic pollutants inside and outside the classrooms. Saliva samples from teachers and students were collected to explore correlations between respiratory viruses in the air and biological samples. Indoor results revealed the punctual exceedance of recommended guidelines for CO2, formaldehyde (HCHO), volatile organic compounds (TVOCs) and PM in the least naturally ventilated classrooms. Significant differences occurred between the classes, with the least ventilated one showing higher average concentrations of CO2, HCHO, NO2, PM10 and PM2.5. A respiratory virus (rhinovirus/enterovirus) was detected in the medium naturally ventilated classroom, although saliva samples tested negative. Suspect screening tentatively identified 65 substances indoors and over 200 outdoors, with approximately half reporting a high toxicological risk based on the Cramer rules. The study provides a comprehensive overview of indoor air quality, respiratory viruses and organic pollutants in university classrooms, highlighting the variations and potential health risks associated with ventilation differences. Full article
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16 pages, 3066 KiB  
Review
Single-Nucleotide Polymorphisms Associated with Mercury Levels and Neurological Symptoms: An Overview
by Jamila Alessandra Perini, Jessica Vilarinho Cardoso, Alana de Oliveira Knesse, Felipe Oliveira Pessoa-Silva, Ana Claudia Santiago de Vasconcellos, Daniel Escorsim Machado and Paulo Cesar Basta
Toxics 2024, 12(3), 226; https://doi.org/10.3390/toxics12030226 - 20 Mar 2024
Viewed by 779
Abstract
Mercury (Hg) pollution is a global public health concern because of its adverse effects on the environment and health. Single-nucleotide polymorphisms (SNPs) have been associated with Hg levels and outcomes. The aim of this review was to describe the research and discuss the [...] Read more.
Mercury (Hg) pollution is a global public health concern because of its adverse effects on the environment and health. Single-nucleotide polymorphisms (SNPs) have been associated with Hg levels and outcomes. The aim of this review was to describe the research and discuss the evidence on the genetic susceptibility of Hg-exposed individuals to the development of neurocognitive disorders. A systematic review was performed to identify the genes/SNPs associated with Hg toxicokinetics and that, therefore, affect neurological function in exposed populations. Observational and experimental studies were identified by screening three databases. Thirteen articles were included (quality score 82–100%) and 8124 individuals were evaluated. Hg exposure was mainly fish consumption (77%) and, in 31% of the studies, the Hg levels exceeded the reference limits. Genetic susceptibility to higher Hg levels and neurotoxicity risk in Hg poisoning were associated with eight (ALAD rs1800435, CYP3A4 rs2740574, CYP3A5 rs776746, CYP3A7 rs2257401, GSTP1 rs1695, MT1A rs8052394, MT1M rs2270836, and MT4 rs11643815) and three (MT1A rs8052394, MT1M rs2270837, and MT2A rs10636) SNPs, respectively, and rs8052394 was associated with both outcomes. The MT1A rs8052394 SNP may be used as a susceptibility biomarker to identify individuals at greater risk for higher Hg levels and the development of neurocognitive disorders in metal-exposed populations. Full article
(This article belongs to the Special Issue Oxidative Stress and Neurotoxicity Induced by Chemicals)
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16 pages, 4255 KiB  
Article
Short-Term Effects of Primary and Secondary Particulate Matter on Ceramide Metabolism, Pro-Inflammatory Response, and Blood Coagulation
by Bin Zhang, Hongbing Xu, Xinghou He, Tong Wang, Mengyao Li, Xuyang Shan, Yutong Zhu, Changjie Liu, Qian Zhao, Xiaoming Song, Yele Sun, Lemin Zheng and Wei Huang
Toxics 2024, 12(3), 225; https://doi.org/10.3390/toxics12030225 - 19 Mar 2024
Viewed by 762
Abstract
Evidence of the precise biological pathway responsible for acute cardiovascular events triggered by particulate matter (PM) exposure from anthropogenic emissions is sparse. We investigated the associations of biomarkers relevant to the pathophysiology of atherothrombosis (ceramide metabolism, pro-inflammatory response, and blood coagulation) with primary [...] Read more.
Evidence of the precise biological pathway responsible for acute cardiovascular events triggered by particulate matter (PM) exposure from anthropogenic emissions is sparse. We investigated the associations of biomarkers relevant to the pathophysiology of atherothrombosis (ceramide metabolism, pro-inflammatory response, and blood coagulation) with primary and secondary components in particulate matter with aerodynamic diameters less than 2.5 μm (PM2.5). A total of 152 healthy participants were followed with four repeated clinical visits between September 2019 and January 2020 in Beijing. Exposure to ambient inorganic aerosols (sulfate, nitrate, ammonium, and chloride), as well as organic aerosols (OA) in PM2.5, was measured by a real-time aerosol chemical speciation monitor, and sources of OA were performed by positive matrix factorization. We found significant increases of 101.9–397.9% in ceramide indicators associated with interquartile-range increases in inorganic aerosols and OA prior to 72 h of exposure. Higher levels of organic and inorganic aerosols in PM2.5 were associated with increases of 3.1–6.0% in normal T cells regulated upon activation and expressed and secreted relevant to the pro-inflammatory response; increases of 276.9–541.5% were observed in D-dimers relevant to coagulation. Detrimental effects were further observed following OA exposure from fossil fuel combustion. Mediation analyses indicated that ceramide metabolism could mediate the associations of PM2.5 components with pro-inflammatory responses. Our findings expand upon the current understanding of potential pathophysiological pathways of cardiovascular events posed by ambient particulates and highlight the importance of reducing primary and secondary PM from anthropogenic combustions. Full article
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24 pages, 7334 KiB  
Article
Assessment of Heavy Metal Contamination in Dust in Vilnius Schools: Source Identification, Pollution Levels, and Potential Health Risks for Children
by Murat Huseyin Unsal, Gytautas Ignatavičius, Arunas Valiulis, Nina Prokopciuk, Roberta Valskienė and Vaidotas Valskys
Toxics 2024, 12(3), 224; https://doi.org/10.3390/toxics12030224 - 19 Mar 2024
Viewed by 821
Abstract
The main objective of this study is to thoroughly evaluate the diversity and sources of heavy metals in the school environment. Specifically, this study examines the presence of heavy metals in the dust found and collected from 24 schools in Vilnius. Employing hierarchical [...] Read more.
The main objective of this study is to thoroughly evaluate the diversity and sources of heavy metals in the school environment. Specifically, this study examines the presence of heavy metals in the dust found and collected from 24 schools in Vilnius. Employing hierarchical cluster analysis, principal component analysis, and positive matrix factorization, we identified combustion-related activities as primary contributors to elevated metal concentrations, notably zinc, scandium, and copper, with PM2.5/PM10 ratios indicating a combustion source. They reveal significant differences in the levels of elements such as arsenic (4.55–69.96 mg/kg), copper (51.28–395.37 mg/kg), zinc, and lead, which are affected by both local environmental factors and human activities. Elevated pollution levels were found in certain school environments, indicating environmental degradation. Pollution assessment and specific element pairings’ strong positive correlations suggested shared origins or deposition processes. While this study primarily assesses non-carcinogenic risks to children based on a health risk assessment model, it acknowledges the well-documented carcinogenic potential of substances such as lead and arsenic. The research emphasizes the immediate necessity for efficient pollution management in educational environments, as indicated by the elevated hazard index for substances such as lead and arsenic, which present non-carcinogenic risks to children. This research offers important insights into the composition and origins of dust pollution in schools. It also promotes the need for broader geographic sampling and prolonged data collection to improve our understanding of pollution sources, alongside advocating for actionable strategies such as environmental management and policy reforms to effectively reduce exposure risks in educational settings. Furthermore, it aims to develop specific strategies to safeguard the health of students in Vilnius and similar urban areas. Full article
(This article belongs to the Section Air Pollution and Health)
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0 pages, 3896 KiB  
Article
Anomalous Gold Concentrations in Hypersaline Wetland Sediments (Laguna Honda, South Spain) Caused by Nanoparticles Used in Agricultural Practices: Environmental Transformation
by Antonio Medina-Ruiz, Juan Jiménez-Millán, Isabel Abad and Rosario Jiménez-Espinosa
Toxics 2024, 12(3), 223; https://doi.org/10.3390/toxics12030223 - 18 Mar 2024
Viewed by 631
Abstract
Illite-rich sediments from the Laguna Honda wetland, an eutrophicated hypersaline wetland with waters enriched in Mg and Ca surrounded by olive groves in the Guadalquivir Basin River (South Spain), are polluted by elevated concentrations of gold (up to 21.9 ppm) due to agricultural [...] Read more.
Illite-rich sediments from the Laguna Honda wetland, an eutrophicated hypersaline wetland with waters enriched in Mg and Ca surrounded by olive groves in the Guadalquivir Basin River (South Spain), are polluted by elevated concentrations of gold (up to 21.9 ppm) due to agricultural practices. The highest gold contents appear in the shore sediments of the lake, where up to 20 µm homoaggregates of fused gold nanoparticles (AuNp) are found. Small nanoaggregates of up to six fused gold nanoparticles and very few isolated nanoparticles around 1 nm in size can also be observed to form heteroaggregates of AuNp-mica, especially in the deeper sediments in the central part of the wetland, where Au concentrations are lower (up to 1.89 ppm). The high nanoparticle concentration caused by the inappropriate application of pesticides favors nanoparticle collision in the wetland’s Mg- and Ca-rich waters and the fast coagulation and deposition of Au homoaggregates in the gold-rich shore sediment of the lake. The interaction of gold nanoparticles with the abundant illite particles in the wetland’s hypersaline waters promotes the simultaneous formation of low-density Au-illite heteroaggregates, which are transported and deposited in the less-rich-in-gold sediments of the central part of the lake. The small sizes of the isolated AuNp and AuNp-fused contacts of the aggregates suggest modifications in the original nanoparticles involving dissolution processes. The presence of bacterial communities resistant to heavy metal stress (Luteolibacter and Maricaulis), as well as the activity of sulfate-reducing bacteria (SRB) and particularly sulfur-oxidizing bacteria (SOB) communities from the shore sediments, favored the high-Eh and low-pH conditions adequate for the destabilization and transport of AuNp. Full article
(This article belongs to the Section Ecotoxicology)
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13 pages, 5519 KiB  
Article
Association between Exposure to Volatile Organic Compounds and the Prevalence of Sleep Problems in US Adults
by Jianyun Sun, Chunyan Gui, Ya Xiao, Runxue Ma, Ce Liu, Li He, Hao Zhao and Bin Luo
Toxics 2024, 12(3), 222; https://doi.org/10.3390/toxics12030222 - 18 Mar 2024
Viewed by 731
Abstract
Background: While mounting evidence suggests a connection between environmental contaminants and sleep problems, it remains uncertain whether exposure to volatile organic compounds (VOCs) specifically is associated with such problems. Methods: Data from the National Health and Nutrition Examination Survey program’s five survey cycles [...] Read more.
Background: While mounting evidence suggests a connection between environmental contaminants and sleep problems, it remains uncertain whether exposure to volatile organic compounds (VOCs) specifically is associated with such problems. Methods: Data from the National Health and Nutrition Examination Survey program’s five survey cycles (2005–2006, 2011–2018) were used to conduct cross-sectional research. Data on short sleep duration (SSD) and self-reported trouble sleeping were collected from questionnaire data. Data on urine VOCs were gathered from laboratory data. The association between urinary VOCs and sleep problems was examined using weighted generalized linear models and the restricted cubic spline (RCS), weighted quantile sum (WQS), and quantile-based g-calculation (QGC) methods. Results: In all, a total of 4131 general adult individuals were included in this study. The prevalence of SSD and self-reported trouble sleeping was 34.11% and 25.03%, respectively. 3,4-MHA, AAMA, AMCC, SBMA, and MA were risk factors for SSD after adjusting several covariates, with the largest effect being AMCC (OR = 1.47, 95% CI: 1.08, 2.02). Risk factors for sleep issues included AAMA, AMCC, CEMA, CYMA, DGBMA, 2HPMA, 3HPMA, MA, and PGA, with AMCC having the highest impact with an OR of 1.69 (95% CI: 1.28, 2.22). Both the WQS model and the QGC model showed that the co-exposure to VOCs was positively associated with SSD and self-reported trouble sleeping, with AMCC being the most influential VOC. Conclusions: According to our research, high levels of single or mixed urine VOCs are linked to a higher prevalence of SSD and self-reported trouble sleeping in the general adult population of the United States. Further prospective and experimental studies are needed in the future to validate these potential relationships and explore the underlying mechanisms. Full article
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19 pages, 2711 KiB  
Article
Toxic Effects of Arsenic on Four Freshwater Aquatic Species and Its Transformation Metabolism in Crucian Carp (Carassius auratus)
by Shizhan Tang, Lei Gao, Dongli Qin, Haitao Wang, Li Huang, Song Wu, Shuyan Bai, Ningning Du, Yanchun Sun, Peng Wang and Zhongxiang Chen
Toxics 2024, 12(3), 221; https://doi.org/10.3390/toxics12030221 - 17 Mar 2024
Viewed by 716
Abstract
Inorganic arsenic is a well-known carcinogen that is much more toxic than its organic counterpart. While much is known about the accumulation and transformation of arsenic in marine organisms, little is known regarding these processes in freshwater aquatic species. In this study, the [...] Read more.
Inorganic arsenic is a well-known carcinogen that is much more toxic than its organic counterpart. While much is known about the accumulation and transformation of arsenic in marine organisms, little is known regarding these processes in freshwater aquatic species. In this study, the acute toxicity and toxicological effects of inorganic arsenic on four freshwater organisms (Cyprinus carpio, Misgurnus anguillicaudatus, Pseudorasbora parva, Eriocheir sinensis) commonly found in rice-fish farming systems were investigated. The organisms exhibited different levels of sensitivity to inorganic arsenic, with crustaceans being more sensitive than fish. Fish were found to be more tolerant to As(V) than As(III). The study also investigated the accumulation, transformation, and release of inorganic arsenic in crucian carp, an omnivorous species with high environmental tolerance. The fish accumulated As(III) rapidly in various tissues, and were able to transport it to other tissues through gills, intestines, and skin. The accumulated As(III) was converted into less toxic forms, such as monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), via methylation. The fish also converted As(III) into arsenate (AsV) via enzymatic and oxidative reactions. After the transferal to clean water, the forms of arsenic in the various tissues decreased rapidly, but the rates of excretion of the four forms of arsenic were not the same among the different tissues. Our results suggest that crucian carp can reduce the environmental toxicity of As(III) at certain concentrations by transforming it into less toxic forms within their bodies. Full article
(This article belongs to the Section Ecotoxicology)
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27 pages, 4983 KiB  
Article
Indications of Endocrine Disruptor Effects of JP-5 Jet Fuel Using a Rat-Model Reproductive Study and an In Vitro Human Hormone Receptor Assay
by William R. Howard, Joyce G. Rohan, Kimberly S. B. Yeager, Chester P. Gut, Kathleen A. Frondorf, Shawn M. McInturf, Nathan M. Gargas and Karen L. Mumy
Toxics 2024, 12(3), 220; https://doi.org/10.3390/toxics12030220 - 16 Mar 2024
Viewed by 659
Abstract
Recent events concerning jet fuel contamination of drinking water have shown that we need a better understanding of the effects of ingested jet fuel. To this end, a reproductive study with ingested jet fuel in rats was undertaken with relatively high concentrations of [...] Read more.
Recent events concerning jet fuel contamination of drinking water have shown that we need a better understanding of the effects of ingested jet fuel. To this end, a reproductive study with ingested jet fuel in rats was undertaken with relatively high concentrations of Jet Propellant (JP)-5 along with a human estrogen receptor activation in vitro assay using JP-5, JP-8, and an alternative jet fuel derived from the camelina plant referred to as HydroRenewable Jet (HRJ) fuel, to help evaluate potential effects of ingested jet fuel. The results of the in vivo study provide evidence that JP-5 can act as an endocrine disruptor, with specific observations including altered hormone levels with JP-5 exposure (significantly lower estradiol levels in male rats and significantly increased Dehydroepiandrosterone levels in females), and a decreased male/female offspring ratio. The in vitro hormone receptor activation assay indicated that JP-5 and JP-8 are capable of upregulating human estrogen receptor (ER) activity, while HRJ was not active in the ER assay. The jet fuels were not able to activate androgen or glucocorticoid receptors in further in vitro assays. These results infer potential endocrine disruption associated with JP-5, with activation of the estrogen receptor as one potential mechanism of action. Full article
(This article belongs to the Special Issue The Toxicological Impact of Jet and Rocket Fuel on Human Health)
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18 pages, 4628 KiB  
Article
A Proof-of-Concept for a Hypolipidemic Brown Trout Model
by Tiago Lourenço, Eduardo Rocha, José Fernando Gonçalves, Maria João Rocha and Tânia Vieira Madureira
Toxics 2024, 12(3), 219; https://doi.org/10.3390/toxics12030219 - 15 Mar 2024
Viewed by 851
Abstract
The impacts of hypolipidemic pharmaceuticals on fish lipid metabolism remain unexplored. However, data points to similar effects and mechanisms of action between fish and humans. Therefore, fish may be a strong model for screening hypolipidemic drug candidates and water pollution by lipid-modulating agents. [...] Read more.
The impacts of hypolipidemic pharmaceuticals on fish lipid metabolism remain unexplored. However, data points to similar effects and mechanisms of action between fish and humans. Therefore, fish may be a strong model for screening hypolipidemic drug candidates and water pollution by lipid-modulating agents. This study aimed to test a new hypolipidemic model assay with juvenile brown trout using atorvastatin (ATV)—a hypolipidemic chemical. We selected 17α-ethinylestradiol (EE2), known to cause hyperlipidemia in fish, to ensure model functionality. Fish received intramuscular injections of 4 μL/g for two weeks under the following experimental conditions: control—C (0.7% NaCl), solvent control—SC (0.7% NaCl, 0.9% ethanol, 0.1% dimethyl sulfoxide), ATV (0.3 μg/g), EE2 (2 μg/g), and a mixture of both compounds—MIX (0.3 μg/g ATV and 2 μg/g EE2). Endpoints included blood lipid biochemistry, hepatic lipid droplet quantification, and liver mRNA expression of lipid-related target genes (related to lipogenesis, lipid transport, and β-oxidation pathways). ATV lowered blood total cholesterol, high-density lipoproteins (HDL), and low-density lipoproteins (LDL) levels, whilst triglycerides and very-low-density lipoproteins (VLDL) were highest under EE2. Hepatic lipid droplet deposition significantly increased in the ATV, EE2, and MIX groups. ATV and MIX caused a significant downregulation of the peroxisome proliferator-activated receptor γ (pparγ) and acetyl Co-A oxidase 3 (acox3). EE2 upregulated acyl-CoA long-chain synthetase 1 (acsl1) and downregulated both fatty acid binding protein 1 (fabp1) and acetyl Co-A oxidase 1-3I (acox1-3I). ATV caused hypolipidemic effects in juvenile brown trout and could even counteract EE2-stimulated hyperlipidemia, reinforcing the potential of fish hypo- and hyperlipidemic models. Full article
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22 pages, 5130 KiB  
Review
Integrated Assessment for the Estrogenic Effects of Pyrethroid Compounds: Defining the Molecular Initiating Events and Key Events for the Adverse Outcome Pathway
by Darlene Mae D. Ortiz, Juyoung Park, Handule Lee and Kwangsik Park
Toxics 2024, 12(3), 218; https://doi.org/10.3390/toxics12030218 - 15 Mar 2024
Viewed by 731
Abstract
Pyrethroids, which are derived from natural insecticides found in chrysanthemum flowers, are widely utilized in various sectors, including agriculture, forestry, horticulture, and personal insect protection. Due to their widespread use, concerns have arisen regarding their potential estrogenic effects on female reproductive health. This [...] Read more.
Pyrethroids, which are derived from natural insecticides found in chrysanthemum flowers, are widely utilized in various sectors, including agriculture, forestry, horticulture, and personal insect protection. Due to their widespread use, concerns have arisen regarding their potential estrogenic effects on female reproductive health. This review aims to address data gaps and inconsistencies in previous studies by defining molecular initiating events and key events within the adverse outcome pathway associated with pyrethroid-induced estrogenic effects. To achieve this, we propose utilizing Integrated Approaches to Testing and Assessment (IATA), which incorporate in vitro assays and in vivo assessments to comprehensively investigate the estrogenic effects of pyrethroids. An initial search was conducted in the PubMed database to identify relevant articles. Subsequently, the findings were classified according to the IATA strategy. This review provides an overview of the current understanding of pyrethroids and their estrogenic effects, identifies data gaps, and highlights the use of IATA in existing studies on the estrogenic effects of various pyrethroids. It emphasizes the urgent need for comprehensive research on the estrogenic effects of pyrethroids and highlights the importance of standardized testing methods like IATA to accurately assess their impact on human and environmental health. By promoting the use of Integrated Testing Strategies (ITSs) and addressing data gaps, researchers and regulators can enhance the accuracy of assessments, ensuring better protection of human and environmental health from the potential estrogenic effects of pyrethroid exposure. Full article
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24 pages, 2722 KiB  
Article
Mechanism of the Synergistic Toxicity of Ampicillin and Cefazoline on Selenastrum capricornutum
by Feng-Ling Huang, Li-Tang Qin, Ling-Yun Mo, Hong-Hu Zeng and Yan-Peng Liang
Toxics 2024, 12(3), 217; https://doi.org/10.3390/toxics12030217 - 14 Mar 2024
Viewed by 932
Abstract
Ampicillin (AMP) and cefazolin (CZO) are commonly used β-lactam antibiotics which are extensively globally produced. Additionally, AMP and CZO are known to have relatively high ecotoxicity. Notably, the mix of AMP and CZO creates a synergistic effect that is more harmful to the [...] Read more.
Ampicillin (AMP) and cefazolin (CZO) are commonly used β-lactam antibiotics which are extensively globally produced. Additionally, AMP and CZO are known to have relatively high ecotoxicity. Notably, the mix of AMP and CZO creates a synergistic effect that is more harmful to the environment, and how exposure to AMP-CZO can induce synergism in algae remains virtually unknown. To yield comprehensive mechanistic insights into chemical toxicity, including dose–response relationships and variations in species sensitivity, the integration of multiple endpoints with de novo transcriptomics analyses were used in this study. We employed Selenastrum capricornutum to investigate its toxicological responses to AMP and CZO at various biological levels, with the aim of elucidating the underlying mechanisms. Our assessment of multiple endpoints revealed a significant growth inhibition in response to AMP at the relevant concentrations. This inhibition was associated with increased levels of reactive oxygen species (ROS) and perturbations in nitrogen metabolism, carbohydrate metabolism, and energy metabolism. Growth inhibition in the presence of CZO and the AMP-CZO combination was linked to reduced viability levels, elevated ROS production, decreased total soluble protein content, inhibited photosynthesis, and disruptions in the key signaling pathways related to starch and sucrose metabolism, ribosome function, amino acid biosynthesis, and the production of secondary metabolites. It was concluded from the physiological level that the synergistic effect of Chlorophyll a (Chla) and Superoxide dismutase (SOD) activity strengthened the growth inhibition of S. capricornutum in the AMP-CZO synergistic group. According to the results of transcriptomic analysis, the simultaneous down-regulation of LHCA4, LHCA1, LHCA5, and sodA destroyed the functions of the photosynthetic system and the antioxidant system, respectively. Such information is invaluable for environmental risk assessments. The results provided critical knowledge for a better understanding of the potential ecological impacts of these antibiotics on non-target organisms. Full article
(This article belongs to the Section Ecotoxicology)
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4 pages, 178 KiB  
Editorial
Editorial for the Special Issue “Environmental Exposure and Reproductive Health”
by Pan Yang
Toxics 2024, 12(3), 216; https://doi.org/10.3390/toxics12030216 - 14 Mar 2024
Viewed by 667
Abstract
In recent decades, the decline in human fertility has emerged as a significant public health concern, garnering global attention [...] Full article
(This article belongs to the Special Issue Environmental Exposure and Reproductive Health)
19 pages, 13348 KiB  
Article
The Impact of Atmospheric Cadmium Exposure on Colon Cancer and the Invasiveness of Intestinal Stents in the Cancerous Colon
by Shuai Zhang, Ruikang Li, Jing Xu, Yan Liu and Yanjie Zhang
Toxics 2024, 12(3), 215; https://doi.org/10.3390/toxics12030215 - 14 Mar 2024
Viewed by 748
Abstract
Background: Inhalation exposure to carcinogenic metals such as cadmium (Cd) is a significant global health concern linked to various cancers. However, the precise carcinogenic mechanism underlying inhalation exposure remains elusive. Methods: In this study, CT26 mouse colon cancer (CC) cells were implanted into [...] Read more.
Background: Inhalation exposure to carcinogenic metals such as cadmium (Cd) is a significant global health concern linked to various cancers. However, the precise carcinogenic mechanism underlying inhalation exposure remains elusive. Methods: In this study, CT26 mouse colon cancer (CC) cells were implanted into BALB/c mice to establish CC mouse models. Some of the CC mice were implanted with intestinal stents. The mice were exposed to atomized oxygen and nitrogen (O2/N2) gas containing Cd. Results: Atmospheric Cd intensified inflammation in CC cells and heightened Nicotinamide Adenine Dinucleotide Phosphate (NADPH) Oxidase 1 (NOX1) activity, which is an indirect measurement of increased reactive oxygen species (ROS) production. This escalated ROS production triggered abnormal Wnt protein secretion, activated the Wnt/β-catenin signaling pathway, and stimulated CC cell proliferation. No discernible body weight effect was seen in the CC mice, possibly due to the later-stage tumor weight gain, which masked the changes in body weight. Cd facilitated colon tumor restructuring and cell migration at the later stage. The implantation of intestinal stents inhibited the expression of Superoxide Dismutase 1 (SOD1) in the colon tumors of the CC mice, with no evident effects on the expression levels of NOX1, SOD2, and Catalase (CAT) enzymes. Elevated ROS levels, indirectly reflected by enzyme activity, did not substantially impact the Wnt/β-catenin signaling pathway and even contributed to slowing its imbalance. Stent implantation eased the inflammation occurring in colon tumors by reducing CC cell proliferation but it induced discomfort in the mice, leading to a reduction in food intake and weight. Conclusions: Cd partially fosters CC tumorigenesis via the ROS-mediated Wnt/β-catenin signaling pathway. The effect of Cd on the invasive effect of intestinal stents in the cancerous colon is not significant. Full article
(This article belongs to the Special Issue Toxicity and Human Health Assessment of Air Pollutants)
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14 pages, 4306 KiB  
Article
Differential Disruption of Glucose and Lipid Metabolism Induced by Phthalates in Human Hepatocytes and White Adipocytes
by Yaru Tian, Miao Xu, Hailin Shang, Lijuan You, Jing Yang, Xudong Jia, Hui Yang, Yongning Wu, Xingfen Yang and Yi Wan
Toxics 2024, 12(3), 214; https://doi.org/10.3390/toxics12030214 - 14 Mar 2024
Viewed by 777
Abstract
Phthalic acid esters (PAEs), commonly used as plasticizers, are pervasive in the environment, leading to widespread human exposure. The association between phthalate exposure and metabolic disorders has been increasingly recognized, yet the precise biological mechanisms are not well-defined. In this study, we explored [...] Read more.
Phthalic acid esters (PAEs), commonly used as plasticizers, are pervasive in the environment, leading to widespread human exposure. The association between phthalate exposure and metabolic disorders has been increasingly recognized, yet the precise biological mechanisms are not well-defined. In this study, we explored the effects of monoethylhexyl phthalate (MEHP) and monocyclohexyl phthalate (MCHP) on glucose and lipid metabolism in human hepatocytes and adipocytes. In hepatocytes, MEHP and MCHP were observed to enhance lipid uptake and accumulation in a dose-responsive manner, along with upregulating genes involved in lipid biosynthesis. Transcriptomic analysis indicated a broader impact of MEHP on hepatic gene expression relative to MCHP, but MCHP particularly promoted the expression of the gluconeogenesis key enzymes G6PC and FBP1. In adipocytes, MEHP and MCHP both increased lipid droplet formation, mimicking the effects of the Peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone (Rosi). Transcriptomic analysis revealed that MEHP predominantly altered fatty acid metabolism pathways in mature adipocytes (MA), whereas MCHP exhibited less impact. Metabolic perturbations from MEHP and MCHP demonstrate shared activation of the PPARs pathway in hepatocytes and adipocytes, but the cell-type discrepancy might be attributed to the differential expression of PPARγ. Our results indicate that MEHP and MCHP disrupt glucose and lipid homeostasis in human liver and adipose through mechanisms that involve the PPAR and adenosine monophosphate-activated protein kinase (AMPK) signaling pathways, highlighting the nuanced cellular responses to these environmental contaminants. Full article
(This article belongs to the Section Human Toxicology and Epidemiology)
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14 pages, 1281 KiB  
Article
Riparian Soil Pollution Caused by Sediment Metal Transport: Seasonal Changes and Ecological Risk Assessment
by Ahmet Çelebi, Bülent Şengörür, Ali Torabi Haghighi and Ali Danandeh Mehr
Toxics 2024, 12(3), 213; https://doi.org/10.3390/toxics12030213 - 13 Mar 2024
Viewed by 822
Abstract
The accumulation of pollutants in the sediment along surface water may negatively affect riparian zones and increase ecological risk. This article investigates the effects of metal sediments on riparian soil via field monitoring and ICP-OES analysis. To this end, pollution levels, seasonal changes, [...] Read more.
The accumulation of pollutants in the sediment along surface water may negatively affect riparian zones and increase ecological risk. This article investigates the effects of metal sediments on riparian soil via field monitoring and ICP-OES analysis. To this end, pollution levels, seasonal changes, and potential sources of the pollutants were determined for the Melen River watershed, Turkey. The ecological statuses (contamination factor, enrichment factor, index of geo-accumulation, pollution index, modified pollution index, and potential and modified ecological risk indexes) of the watershed were also analyzed. Although no significant seasonal differences in the metal sediments were observed, their spatial distribution in the sediments and riparian soils varied markedly. Cr (11.4 to 136), Co (7.7 to 21.52), Cu (11.4 to 76.6), and Ni (14.06 to 128.2) recorded as mg/kg significantly increased from the upstream to the downstream. The metals possessing the highest risk in the sediment and riparian soil regarding the river health were Cu, Co, and Ni. The risk values were found to be heavily polluted (PI > 3 and MPI > 10), and the risk indexes were above the “desired environment without the risk”. The risk index was found to be more than 50, and the modified risk indexes exceeded 200 at many points. The transportation of pollutants in surface water became evident in the sediment, resulting in adverse effects on the riparian zone and the ecological system. Full article
(This article belongs to the Section Metals and Radioactive Substances)
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17 pages, 526 KiB  
Article
Long-Term Environmental Methylmercury Exposure Is Associated with Peripheral Neuropathy and Cognitive Impairment among an Amazon Indigenous Population
by Bruno H. Rebouças, Gabriel T. Kubota, Rogério A. A. Oliveira, Bruna D. Pinto, Roberta M. Cardoso, Ana C. S. Vasconcellos and Paulo C. Basta
Toxics 2024, 12(3), 212; https://doi.org/10.3390/toxics12030212 - 12 Mar 2024
Viewed by 1224
Abstract
Widespread contamination of the Amazon basin with mercury has been reported to occur since at least the mid-80s due to heavy gold mining activity. Although initial studies have indicated that this may lead to deleterious neurological consequences to the indigenous populations living in [...] Read more.
Widespread contamination of the Amazon basin with mercury has been reported to occur since at least the mid-80s due to heavy gold mining activity. Although initial studies have indicated that this may lead to deleterious neurological consequences to the indigenous populations living in the region, further research is needed to better characterize the neurological burden of such long-term exposure. With this aim, a cross-sectional exploratory study has been conducted with the Yanomami indigenous population residing in a northern Amazon region. All participants underwent a structured interview; detailed neurological examination, including assessment for cognitive, motor, coordination, and sensory functions; and laboratorial testing for serum hemoglobin, blood glucose, and methylmercury levels in hair samples. This study enrolled 154 individuals of 30.9 ± 16.8 years of age, of which 56.1% were female. Mean methylmercury levels in hair were 3.9 ± 1.7 µg/g. Methylmercury levels in hair > 6.0 µg/g were found in 10.3%. Among participants with hair methylmercury levels ≥ 6.0 μg/g, the prevalences of peripheral neuropathy and reduced cognitive performance were, respectively, 78.8% (95%CI 15–177%, p = 0.010) and 95.9% (95%CI 16–230.8%, p = 0.012) higher than those of individuals with lower levels. These results suggest that chronic mercury exposure may lead to significant and potentially irreversible neurotoxicity to Yanomami population living in the northern Amazon basin. Full article
(This article belongs to the Section Neurotoxicity)
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19 pages, 2996 KiB  
Article
Redox Homeostasis Disclosed in the Saltmarsh Plant Halimione portulacoides upon Short Waterborne Exposure to Inorganic Mercury
by Patrícia Pereira, Joana Luísa Pereira, Ana Marques, Carlos Marques, Fátima Brandão, Rute Cesário, Silja Frankenbach, João Serôdio, Fernando J. M. Gonçalves, João Canário and Mário Pacheco
Toxics 2024, 12(3), 211; https://doi.org/10.3390/toxics12030211 - 12 Mar 2024
Viewed by 712
Abstract
The saltmarsh plant Halimione portulacoides was shortly exposed to realistic levels of inorganic mercury (iHg) with the aim of investigating the adaptative processes of the roots and leaves regarding redox homeostasis, physiology, and Hg accumulation. Plants were collected at a contaminated (CONT) and [...] Read more.
The saltmarsh plant Halimione portulacoides was shortly exposed to realistic levels of inorganic mercury (iHg) with the aim of investigating the adaptative processes of the roots and leaves regarding redox homeostasis, physiology, and Hg accumulation. Plants were collected at a contaminated (CONT) and a reference (REF) site to address the interference of contamination backgrounds. The influence of major abiotic variables (i.e., temperature and light) was also examined. Total Hg levels, antioxidant enzymes, lipid peroxidation (LPO), and photosynthetic activity were analyzed after 2 and 4 h of exposure. A poor accumulation of Hg in the roots was noticed, and no translocation to the stems and leaves was found, but plants from the CONT site seemed more prone to iHg uptake (in winter). Despite this, antioxidant modulation in the roots and leaves was found, disclosing, in winter, higher thresholds for the induction of enzymatic antioxidants in CONT leaves compared to REF plants, denoting that the former are better prepared to cope with iHg redox pressure. Consistently, CONT leaves exposed to iHg had remarkably lower LPO levels. Exposure did not impair photosynthetic activity, pinpointing H. portulacoides’ ability to cope with iHg toxicity under very-short-term exposure. Biochemical changes were noticed before enhancements in accumulation, reinforcing the relevance of these responses in precociously signaling iHg toxicity. Full article
(This article belongs to the Section Ecotoxicology)
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13 pages, 5565 KiB  
Article
The Influence of Textile Type, Textile Weight, and Detergent Dosage on Microfiber Emissions from Top-Loading Washing Machines
by Pongsiri Julapong, Palot Srichonphaisarn, Thidarat Meekoch, Carlito Baltazar Tabelin, Onchanok Juntarasakul and Theerayut Phengsaart
Toxics 2024, 12(3), 210; https://doi.org/10.3390/toxics12030210 - 12 Mar 2024
Viewed by 1151
Abstract
The use of washing machines to wash textiles gradually breaks down synthetic fibers like polyethylene terephthalate (PET) or polyester (PES) in diverse clothing materials, a process that is growing in notoriety because it generates microplastics (MPs). In this study, we investigated the emission [...] Read more.
The use of washing machines to wash textiles gradually breaks down synthetic fibers like polyethylene terephthalate (PET) or polyester (PES) in diverse clothing materials, a process that is growing in notoriety because it generates microplastics (MPs). In this study, we investigated the emission of microfibers, including both microplastic fibers (MPFs) and natural fibers (MFs), from top-loading washing machines. Our investigation focused on four popular textiles with prevalent weave structures (plain, satin, and twill): (i) PES, (ii) tetron cotton (TC), (iii) chief value cotton (CVC), and (iv) cotton (CO) fabrics. This study also examined the effects of textile weight and detergent dosage on MF emissions. After washing, MFs were collected through filtration, and their concentrations were determined using micro-Fourier Transform Interferometry (μFTIR). The results showed varying concentrations of MFs in the washing effluent depending on the type of textile. Specifically, CVC exhibited the highest emission at 4022 particles/L, followed by TC, PES, and CO at 2844 particles/L, 2382 particles/L, and 2279 particles/L, respectively. The hydrophobic nature of PES makes this type of textile prone to rapid degradation in detergent-rich environments, leading to high MF emissions. Additionally, the mechanical properties of textiles, such as tensile and bending strengths, may play a crucial role in the generation of MFs in washing machines. Textiles made of CO with twill weaves demonstrated superior strength and correlated with lower emissions of MFs. In comparison, textiles made of CVC and satin weave exhibited lower mechanical properties, which could explain their high emissions of MFs. Finally, the MF emissions of textiles composed of PES and TC, which are plain weaved, could be attributed to their intermediate mechanical properties compared with those of CVC and CO. Full article
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14 pages, 1515 KiB  
Review
Ambient Air Pollution and Vision Disorder: A Systematic Review and Meta-Analysis
by Zhuo Han, Chao Zhao, Yuhua Li, Meng Xiao, Yuewei Yang, Yizhuo Zhao, Chunyu Liu, Juan Liu and Penghui Li
Toxics 2024, 12(3), 209; https://doi.org/10.3390/toxics12030209 - 10 Mar 2024
Viewed by 914
Abstract
The effects of air pollution on physical health are well recognized, with many studies revealing air pollution’s effects on vision disorder, yet no relationship has been established. Therefore, a meta-analysis was carried out in this study to investigate the connection between vision disorder [...] Read more.
The effects of air pollution on physical health are well recognized, with many studies revealing air pollution’s effects on vision disorder, yet no relationship has been established. Therefore, a meta-analysis was carried out in this study to investigate the connection between vision disorder and ambient particles (diameter ≤ 2.5 µm (PM2.5), diameter ≤ 10 µm (PM10)) and gaseous pollutants (nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), Ozone (O3)). Twelve relevant studies published by 26 February 2024 were identified in three databases. A pooled odds ratios (ORs) of 95% confidence intervals (CIs) were obtained using random-effects meta-analysis models. Meta-analysis results revealed that for every 10 µg/m3 increase in PM2.5 and NO2 exposure, a substantially higher incidence of vision disorder was observed (OR = 1.10; 95% CI: 1.01, 1.19; OR = 1.08, 95% CI: 1.00, 1.16). No significant correlation existed between exposure to PM10, SO2 and CO and vision disorder. However, O3 exposure was negatively associated with vision disorder. In addition, subgroup analyses revealed that PM2.5 exposure was significantly correlated with the risk of glaucoma and age-related macular degeneration and that children and adolescents were more susceptible to NO2 and PM2.5 than adults. Overall, exposure to air pollutants, especially PM2.5 and NO2, may increase the incidence of vision disorder. Full article
(This article belongs to the Special Issue Toxicity and Human Health Assessment of Air Pollutants)
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23 pages, 2097 KiB  
Article
Mercury in Fish and Human Hair and Estimated Dietary Intake in a Riverside Community of the Madeira River Basin in the Brazilian Amazon
by Thayson Araujo Canela, Lucas Cabrera Monteiro, Cássio da Silva Cabral, Fábio da Silva Ximenes, Iuri Aparecida da Silva Oliveira, José Vicente Elias Bernardi, Ronaldo de Almeida and Wanderley Rodrigues Bastos
Toxics 2024, 12(3), 208; https://doi.org/10.3390/toxics12030208 - 09 Mar 2024
Viewed by 947
Abstract
Mercury (Hg) is a chemical element that poses risks to human health due to its high toxicity and environmental persistence. We determined the total Hg (THg) and methyl Hg (MeHg) concentrations in hair samples from residents of the Demarcação District (Porto Velho, Rondônia) [...] Read more.
Mercury (Hg) is a chemical element that poses risks to human health due to its high toxicity and environmental persistence. We determined the total Hg (THg) and methyl Hg (MeHg) concentrations in hair samples from residents of the Demarcação District (Porto Velho, Rondônia) in the Brazilian Amazon, as well as in water and fish samples, to evaluate factors influencing human exposure. The average THg concentration in human hair was 7.86 ± 6.78 mg kg−1 and it was significantly higher in men, with an increasing trend related to age. There was no significant difference between female age groups. Human exposure to Hg through water was negligible compared to fish consumption. The average weekly intake estimates in the community varied between 1.54 and 4.62 μg kg−1, substantially higher than the recommended limit. The fish species with the highest amounts safe for daily consumption were herbivores and detritivores. Our results contribute to an understanding of how exposure to Hg affects the health of riverside populations and provide insights for new research to develop methods to mitigate such exposure and thus improve the quality of life of Amazonian people. Full article
(This article belongs to the Section Metals and Radioactive Substances)
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16 pages, 3177 KiB  
Article
Persulfate–Based Advanced Oxidation Process for Chlorpyrifos Degradation: Mechanism, Kinetics, and Toxicity Assessment
by Youxin Xu, Chenxi Zhang, Haobing Zou, Guangrong Chen, Xiaomin Sun, Shuguang Wang and Huifang Tian
Toxics 2024, 12(3), 207; https://doi.org/10.3390/toxics12030207 - 09 Mar 2024
Viewed by 922
Abstract
Persulfate-based advanced oxidation process has been proven to be a promising method for the toxic pesticide chlorpyrifos (CPY) degradation in wastewater treatment. However, due to the limitation for the short-lived intermediates detection, a comprehensive understanding for the degradation pathway remains unclear. To address [...] Read more.
Persulfate-based advanced oxidation process has been proven to be a promising method for the toxic pesticide chlorpyrifos (CPY) degradation in wastewater treatment. However, due to the limitation for the short-lived intermediates detection, a comprehensive understanding for the degradation pathway remains unclear. To address this issue, density functional theory was used to analyze the degradation mechanism of CPY at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d,p) level, and computational toxicology methods were employed to explore the toxicity of CPY and its degradation products. Results show that hydroxyl radicals (·OH) and sulfate radicals (SO4•−) initiate the degradation reactions by adding to the P=S bond and abstracting the H atom on the ethyl group, rather than undergoing α-elimination of the pyridine ring in the persulfate oxidation process. Moreover, the addition products were attracted and degraded by breaking the P–O bond, while the abstraction products were degraded through dealkylation reactions. The transformation products, including 3,5,6-trichloro-2-pyridynol, O,O-diethyl phosphorothioate, chlorpyrifos oxon, and acetaldehyde, obtained through theoretical calculations have been detected in previous experimental studies. The reaction rate constants of CPY with ·OH and SO4•− were 6.32 × 108 and 9.14 × 108 M−1·s−1 at room temperature, respectively, which was consistent with the experimental values of 4.42 × 109 and 4.5 × 109 M−1 s−1. Toxicity evaluation results indicated that the acute and chronic toxicity to aquatic organisms gradually decreased during the degradation process. However, some products still possess toxic or highly toxic levels, which may pose risks to human health. These research findings contribute to understanding the transformation behavior and risk assessment of CPY in practical wastewater treatment. Full article
(This article belongs to the Special Issue Advanced Processes for Wastewater Treatment)
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11 pages, 1961 KiB  
Article
A Pilot Study on Bioaccumulation and Tissue Distribution of Mercury in Barn Swallow (Hirundo rustica)
by Li Tian, Yujing Zhu, Ruiming Yu and Xiaobo Zheng
Toxics 2024, 12(3), 206; https://doi.org/10.3390/toxics12030206 - 08 Mar 2024
Viewed by 882
Abstract
Although extensive research has been carried out on the occurrence of mercury (Hg) in biota, bioaccumulation and tissue distribution of Hg in songbirds have not been well characterized. In the present study, Hg was investigated in insects and barn swallows (Hirundo rustica [...] Read more.
Although extensive research has been carried out on the occurrence of mercury (Hg) in biota, bioaccumulation and tissue distribution of Hg in songbirds have not been well characterized. In the present study, Hg was investigated in insects and barn swallows (Hirundo rustica) to explore the bioaccumulation characteristics of Hg. Hg in swallow feathers and tissues including muscle, liver, and bone was investigated to determine the tissue distribution of Hg. The concentrations of Hg were 1.39 ± 1.01 μg/g, 0.33 ± 0.09 μg/g, 0.47 ± 0.10 μg/g, and 0.23 ± 0.09 μg/g in feather, muscle, liver, and bone samples, respectively. The trophic magnification factor of Hg in swallows and insects was higher than 1. However, the Hg concentrations in swallow feathers were not significantly correlated with stable isotope values of carbon or nitrogen, which implies the complex food sources and exposure processes of Hg for swallows. Feathers had significantly higher concentrations of Hg than liver, muscle, and bone samples (p < 0.01 for all comparisons). Feather, muscle, bone, and other organs had fractions of 64.4 ± 11.9%, 6.07 ± 2.06%, 20.0 ± 8.19%, and 9.56 ± 2.96% in total body burden of Hg in swallows. Hg in feathers contributed more than half of Hg in the whole body for most swallow individuals. Swallows may efficiently eliminate Hg by molting, and the excretion flux of Hg and other contaminants via molting deserves more investigation. Full article
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6 pages, 188 KiB  
Editorial
Editorial “Special Issue Clinical and Post Mortem Toxicology”
by Eric J. F. Franssen
Toxics 2024, 12(3), 205; https://doi.org/10.3390/toxics12030205 - 08 Mar 2024
Viewed by 918
Abstract
This Special Issue addresses the challenges faced in detecting the exposure and intoxications of various (recreative) drugs and novel active psychoactive drugs [...] Full article
(This article belongs to the Special Issue Clinical and Post-Mortem Toxicology)
28 pages, 6501 KiB  
Review
Trends in Mercury Contamination Distribution among Human and Animal Populations in the Amazon Region
by Irvin Martoredjo, Lenize Batista Calvão Santos, Jéssica Caroline Evangelista Vilhena, Alex Bruno Lobato Rodrigues, Andréia de Almeida, Carlos José Sousa Passos and Alexandro Cezar Florentino
Toxics 2024, 12(3), 204; https://doi.org/10.3390/toxics12030204 - 07 Mar 2024
Viewed by 1207
Abstract
Mercury contamination in the Amazon arising from both natural sources and intensive mining activities in the region is a significant public health concern. This metal is used to separate Au from sediments. Accordingly, this study aimed to assess the impact of mining on [...] Read more.
Mercury contamination in the Amazon arising from both natural sources and intensive mining activities in the region is a significant public health concern. This metal is used to separate Au from sediments. Accordingly, this study aimed to assess the impact of mining on mercury contamination in the animal and human populations of the Amazon. This overall objective was pursued through a systematic review of the existing literature to assess the impact of Hg and identify gaps in geographic coverage arising from this assessment. Herein, we employed PECO and PRISMA-ScR protocols to select articles published between 2017 and 2023 based on projected points on a map within the biogeographic boundaries of the Amazon. We found that mercury concentrations increase with trophic levels, reaching high values of 3.7 µg/g in the muscles of predatory fish and 34.9 µg/g in human hair. The mean level of mercury in human hair in the whole (Amazon) region exceeds 6 µg/g, surpassing tolerance levels. Although mining regions show high concentrations of Hg, the highest incidence was observed among populations with fish-based diets. It was concluded that continuous research and monitoring of fish in the region are required in order to accurately assess the risk associated with Hg contamination, especially since fish are the main source of protein in this region. Full article
(This article belongs to the Special Issue Mercury Cycling and Health Effects)
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23 pages, 3719 KiB  
Article
Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics
by Shuhai Sun, Zhonghe Wang, Qikun Pu, Xinao Li, Yuhan Cui, Hao Yang and Yu Li
Toxics 2024, 12(3), 203; https://doi.org/10.3390/toxics12030203 - 06 Mar 2024
Viewed by 725
Abstract
The degradation of fluoroquinolones (FQs) via advanced oxidation processes (AOPs) is a promising avenue, yet the complete mineralization of certain FQ molecules remains elusive, raising concerns about the formation of toxic by-products. This study delineates five primary AOP degradation pathways for 16 commercially [...] Read more.
The degradation of fluoroquinolones (FQs) via advanced oxidation processes (AOPs) is a promising avenue, yet the complete mineralization of certain FQ molecules remains elusive, raising concerns about the formation of toxic by-products. This study delineates five primary AOP degradation pathways for 16 commercially available FQ molecules, inferred from existing literature. Density functional theory (DFT) was employed to calculate the bond dissociation energies within these pathways to elucidate the correlation between bond strength and molecular architecture. Subsequently, Comparative Molecular Similarity Index Analysis (CoMSIA) models were constructed for various degradation reactions, including piperazine ring cleavage, defluorination, hydroxylation, and piperazine ring hydroxylation. Three-dimensional contour maps generated from these models provide a deeper understanding of the interplay between FQ molecular structure and bond dissociation energy. Furthermore, toxicity predictions for 16 FQ molecules and their advanced oxidation intermediates, conducted using VEGA 1.2.3 software, indicate that degradation products from pathways P2 and P5 pose a heightened health risk relative to their parent compounds. Furthermore, the application of the Multwfn program to compute the Fukui function for FQ molecules discerns the disparity in degradation propensities, highlighting that N atoms with higher f0 values can augment the likelihood of piperazine ring cleavage. HOMO-LUMO distribution diagrams further confirm that methoxy substitution at the 1-position leads to a dilution of HOMOs on the piperazine ring and an increased energy gap for free radical reactions, diminishing the reactivity with hydroxyl radicals. This study elucidates the pivotal role of structural characteristics in FQ antibiotics for their degradation efficiency within AOPs and unveils the underlying mechanisms of bond dissociation energy disparities. The toxicity parameter predictions for FQ molecules and their intermediates offer unique perspectives and theoretical underpinnings for mitigating the use of high-risk FQs and for devising targeted degradation strategies to circumvent the generation of toxic intermediates in AOPs through molecular structure optimization. Full article
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16 pages, 6464 KiB  
Article
Pollution Characteristics and Source Apportionment of Black Carbon Aerosols during Spring in Beijing
by Wenkai Lei, Xingru Li, Zhongyi Yin, Lan Zhang and Wenji Zhao
Toxics 2024, 12(3), 202; https://doi.org/10.3390/toxics12030202 - 05 Mar 2024
Viewed by 767
Abstract
Black carbon (BC) aerosols are important for absorbing aerosols, affecting global climate change and regional air quality, and potentially harming human health. From March to May 2023, we investigated black carbon aerosol levels and air pollution in Beijing. Employing methods such as linear [...] Read more.
Black carbon (BC) aerosols are important for absorbing aerosols, affecting global climate change and regional air quality, and potentially harming human health. From March to May 2023, we investigated black carbon aerosol levels and air pollution in Beijing. Employing methods such as linear regression, Potential Source Contribution Function (PSCF) and Concentration-Weighted Trajectory (CWT), we analyzed the characteristics and sources of black carbon aerosols in the region. Results indicate that the light absorption coefficients of BC and BrC decrease with increasing wavelength, with BrC accounting for less than 40% at 370 nm. Daily variations in BC and PM2.5 concentrations exhibit similar trends, peaking in March, and BC displays a distinct bimodal hourly concentration structure during this period. Aethalometer model results suggest that liquid fuel combustion contributes significantly to black carbon (1.08 ± 0.71 μg·m−3), surpassing the contribution from solid fuel combustion (0.31 ± 0.2 μg·m−3). Furthermore, the significant positive correlation between BC and CO suggests that BC emissions in Beijing predominantly result from liquid fuel combustion. Potential source area analysis indicates that air masses of spring in Beijing mainly originate from the northwest (40.93%), while potential source areas for BC are predominantly distributed in the Beijing–Tianjin–Hebei region, as well as parts of the Shandong, Shanxi and Henan provinces. Moreover, this study reveals that dust processes during spring in Beijing have a limited impact on black carbon concentrations. This study’s findings support controlling pollution in Beijing and improving regional air quality. Full article
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15 pages, 1524 KiB  
Article
Firefighters’ Occupational Exposure in Preparation for Wildfire Season: Addressing Biological Impact
by Filipa Esteves, Klara Slezakova, Joana Madureira, Josiana Vaz, Adília Fernandes, Simone Morais, Maria do Carmo Pereira, João Paulo Teixeira and Solange Costa
Toxics 2024, 12(3), 201; https://doi.org/10.3390/toxics12030201 - 05 Mar 2024
Viewed by 1133
Abstract
The characterization of wildland firefighters’ occupational exposure must consider different exposures, including those at the fire station. The present study aimed to characterize the occupational exposure of 172 Northern Portuguese wildland firefighters in fire stations during the pre-wildfire season of 2021. The biological [...] Read more.
The characterization of wildland firefighters’ occupational exposure must consider different exposures, including those at the fire station. The present study aimed to characterize the occupational exposure of 172 Northern Portuguese wildland firefighters in fire stations during the pre-wildfire season of 2021. The biological impact of estimated inhaled doses of PM10 and PM2.5 (indoor/outdoor) was accessed through a buccal micronucleus cytome (BMCyt) assay in exfoliated buccal cells of a subgroup of 80 firefighters. No significant association was found between estimated inhaled doses of PM10 and PM2.5 (mean 1.73 ± 0.43 µg kg−1 and 0.53 ± 0.21 µg kg−1, respectively) and biological endpoints. However, increased frequencies of cell death parameters were found among subjects of the Permanent Intervention Teams (full-time firefighters). The intake of nutritional supplements was associated with a significant decrease in micronucleus frequencies (i.e., DNA damage or chromosome breakage). In addition, our findings showed a significantly increased frequency of cell death endpoints (i.e., nuclear fragmentation) with coffee consumption, while daily consumption of vegetables significantly decreased it (i.e., nuclear shrinkage). Our results provide data on the occupational exposure of wildland firefighters while working in fire stations during the pre-wildfire season, providing the essential baseline for further studies throughout the wildfire season. Full article
(This article belongs to the Special Issue Firefighters’ Occupational Exposures and Health Risks)
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