Benzo[a]pyrene Research Articles

Occurrence and exposure to polycyclic aromatic hydrocarbons (PAHs) in traditional dry-cured or smoked meat products from Brazil

Polycyclic aromatic hydrocarbons (PAHs) are classified as environmental and food contaminants, with several adverse health effects, especially genotoxic and carcinogenic actions. In processed meats, they are the major contaminants, especially those subjected to smoking processes. Considering that the population is exposed to PAHs through several routes, and that the ingestion of contaminated food is considered the main one, evaluating the concentrations of these contaminants in food becomes essential, as well as the exposure and risk to the population at different ages through ingestion of the evaluated products. In the current study, the levels of nine PAHs (PAH9) were measured in 205 processed meat products commercially available and with high consumption in Brazil. The methodology involved saponification, extraction with n-hexane, purification with solid-phase extraction (SPE) silica cartridges, and quantification by liquid chromatography with fluorescence detection. In general, 83% of all samples were contaminated with at least one of the studied PAHs, and the measured PAH9 levels ranged between < LOQ-108.24 µg/kg. The highest mean of total PAHs was found in smoked sausage (108.24 μg/kg), while the lowest content was found in ham (1.83 μg/kg). Benzo[a]pyrene (BaP) and PAH4 (benz[a]anthracene, chrysene, benzo[b]fluoranthene, and BaP) exceeded the maximum permissible limits of the European Union (EU) in three (1.5%) and 18 samples (8.7%), respectively. The results of margin of exposure results (MOE ≥ 10,000) and incremental lifetime cancer risk (ILCR) values (10 − 6 < ILCR < 10 − 4) in all ten types of meat indicated there were low significant potential health problems related to meat products consumption for the Brazilian population.Graphical

Effects of Polycyclic Aromatic Hydrocarbons on Soil Bacterial and Fungal Communities in Soils

Soil organic pollution (such as heavy metals, PAHs, etc.) has caused serious environmental problems, which have resulted in unexpected effects on contaminated soil ecosystems. However, knowledge of the interactions between environmental PAHs and bacterial and fungal communities is still limited. In this study, soil samples from different PAH-contaminated areas including non-contaminated areas (NC), low-contaminated areas (LC), and high-contaminated areas (HC) were selected. Results of toxic equivalent quantity (TEQ) indicated that Benzo[a]pyrene (BaP) and Dibenzo[a,h]anthracene (DBahA) constituted the main TEQs of ∑16PAHs. Incremental lifetime cancer risk (ILCR) assessment revealed that the main pathway of exposure to soil PAHs was dermal contact in adults and children. Furthermore, adults faced a higher total cancer risk (including dermal contact, ingestion, and inhalation) from soil PAHs than children. The microbial community composition analysis demonstrated that soil PAHs could decrease the diversity of bacterial and fungal communities. The relative abundance of Acidobacteriota, Gemmatimonadota, Fimicutes, Bacteroidota, Ascomycota, and Basidiomycota exhibited varying degrees of changes under different concentrations of PAHs. Benzo[a]anthracene (BaA) and Chrysene (Chr) drove the bacterial community composition, while BaP and DBahA drove the fungal community compositions. Co-occurrence network analysis revealed the high contamination levels of PAHs that could change the relationships among different microorganisms and reduce the complexity and stability of fungal and bacterial networks. Overall, these findings provide comprehensive insight into the responses of bacterial and fungal communities to PAHs.

Investigation of the modification of gold electrodes by electrochemical molecularly imprinted polymers as a selective layer for the trace level electroanalysis of PAH

Electrochemical molecularly imprinted polymers (e-MIPs) were grafted for the first time as a thin layer to the surface of a gold electrode to perform trace level electroanalysis of benzo(a)pyrene (BaP). This was achieved by controlled/living radical photopolymerization of a redox tracer monomer (ferrocenylmethyl methacrylate, FcMMA) with ethylene glycol dimethacrylate in the presence of benzo(a)pyrene as the template molecule. For that purpose, a novel photoiniferter-derived SAM was first deposited on the gold surface. The SAM formation was monitored by cyclic voltammetry and electrochemical impedance spectroscopy. Then, the “grafting from” of the e-MIP was achieved upon photoirradiation during a controlled time. Differential pulse voltammetry was used to quantify BaP in aqueous solution by following the modification of the signal of FcMMA. A limit of detection of 0.19 nM in water and a linear range of 0.66 nM to 4.30 nM, were determined, thus validating the enhancement of sensitivity induced by the close contact between the e-MIP and the electrode, and the improved transfer electron.

Magnetic coal gangue-based catalysts for peroxymonosulfate activation and benzo[a]pyrene degradation: The construction of Fe and N dual active sites

The magnetic coal gangue (CG)-based catalysts were successfully prepared by impregnation-calcination method with iron (Fe) and nitrogen (N) co-doping for peroxymonosulfate (PMS) activation, illustrating excellent catalytic property with 100.00 % removal rate of benzo[a]pyrene (BaP). Additionally, Fe/N co-doped CG catalysts (Fe-N-CG) possess desirable performance against co-existing anions and organic matter (HA), with a nearly 80.00 % removal rate in actual water systems. The mechanism of activating PMS and removing BaP was comprehensively analyzed through a series of characterizations and experiments, proving that the Fe and N double reaction sites could enhance the contribution of radical paths and non-radical paths for BaP degradation. Finally, the safety and prospects for practical environmental remediation via Fe-N-CG for PMS activation were further evaluated by ECOSAR toxicity analysis software and mung bean growth experiments. In summary, the development of Fe-N-CG widened the high-value utilization of CG and supplied a deep insight into the restoration of organically polluted environments.

A fundamental analysis on PAHs in food products to detect the toxicity index using fuzzy logic system

Polycyclic Aromatic Hydrocarbons (PAHs) are complex chemical compounds that occur naturally in unprocessed food when it is exposed to contaminated air during transportation, natural emission such as volcano, forest fire and through pesticides spray. It is reported by different agencies that there are 16 types of PAHs in which BaP (Benzo[a] pyrene), BaA (Benz[a]anthracene), BbF(Benzo [b] fluoranthene), Chr (Chrysene) are considered to be carcinogenic and it can occur due to different processes. In processed food it occurs due to various processing methods like overheating, incomplete burning, drying etc. The presence of PAH in food is conventionally found through analytical, traditional, and semi-automatic methods. These methods are found to be valuable but expensive and time-consuming. Further, these methods are used only for the detection of PAHs and the toxicity level is measured or identified based on expert knowledge of researchers and the Standards. Therefore, in this research, a simple harmfulness index system has been developed using Fuzzy Logic System(FLS). The proposed system has been designed based on the PAH values of different food and food products. Hence to initiate the study and to determine the significance of the results, PAH data have been collected from different articles that have investigated food products experimentally. These PAH data were analyzed using statistical measures such as Min, Mean, Max, Standard Deviation, Variance and Kurtosis method. Based on the observations from the results, the fuzzy sets were designed with four membership functions for each PAH and the rules were framed. The strength output from the inference engine has been associated with harmfulness index such as normal, low risk, medium risk, and high risk. From the evaluation, it can be observed that 89.72% of the food samples were recognized along with their degree of harmfulness. Also it can be inferred that 11% of the misclassified samples showed clear metrics of their harmfulness with PAH variations.

Distribution of polycyclic aromatic hydrocarbons and carcinogenic risk assessment in street-barbecued foods in China

Street-barbecued foods, despite their popularity, produce carcinogenic polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP) due to incomplete charcoal combustion, direct food-fuel contact, and excessive heating. This study analyzed barbecued foods from high-traffic street vendors using high-performance liquid chromatography. Among five food categories (meat, vegetable, aquatic, starch, and soy products), eight foods exceeded China’s BaP limit (5 µg/kg) and twelve exceeded the EU limit (2 µg/kg). The highest BaP and PAH4 levels were found in barbecued beef and pork belly, respectively. Chr levels were notably high due to open flame exposure. Health risk assessments indicated fourteen foods posed elevated carcinogenic risks. This study highlights the necessity of consumption control to mitigate these risks and provides evidence for improving street food safety and dietary security.

Proteogenomic analysis of air-pollution-associated lung cancer reveals prevention and therapeutic opportunities

Air pollution significantly impacts lung cancer progression, but there is a lack of a comprehensive molecular characterization of clinical samples associated with air pollution. Here, we performed a proteogenomic analysis of lung adenocarcinoma (LUAD) in 169 female never-smokers from the Xuanwei area (XWLC cohort), where coal smoke is the primary contributor to the high lung cancer incidence. Genomic mutation analysis revealed XWLC as a distinct subtype of LUAD separate from cases associated with smoking or endogenous factors. Mutational signature analysis suggested that Benzo[a]pyrene (BaP) is the major risk factor in XWLC. The BaP-induced mutation hotspot, EGFR-G719X, was present in 20% of XWLC which endowed XWLC with elevated MAPK pathway activations and worse outcomes compared to common EGFR mutations. Multi-omics clustering of XWLC identified four clinically relevant subtypes. These subgroups exhibited distinct features in biological processes, genetic alterations, metabolism demands, immune landscape, and radiomic features. Finally, MAD1 and TPRN were identified as novel potential therapeutic targets in XWLC. Our study provides a valuable resource for researchers and clinicians to explore prevention and treatment strategies for air-pollution-associated lung cancers.

Proteogenomic analysis of air-pollution-associated lung cancer reveals prevention and therapeutic opportunities.

Air pollution significantly impacts lung cancer progression, but there is a lack of a comprehensive molecular characterization of clinical samples associated with air pollution. Here, we performed a proteogenomic analysis of lung adenocarcinoma (LUAD) in 169 female never-smokers from the Xuanwei area (XWLC cohort), where coal smoke is the primary contributor to the high lung cancer incidence. Genomic mutation analysis revealed XWLC as a distinct subtype of LUAD separate from cases associated with smoking or endogenous factors. Mutational signature analysis suggested that Benzo[a]pyrene (BaP) is the major risk factor in XWLC. The BaP-induced mutation hotspot, EGFR-G719X, was present in 20% of XWLC which endowed XWLC with elevated MAPK pathway activations and worse outcomes compared to common EGFR mutations. Multi-omics clustering of XWLC identified four clinically relevant subtypes. These subgroups exhibited distinct features in biological processes, genetic alterations, metabolism demands, immune landscape, and radiomic features. Finally, MAD1 and TPRN were identified as novel potential therapeutic targets in XWLC. Our study provides a valuable resource for researchers and clinicians to explore prevention and treatment strategies for air-pollution-associated lung cancers.

Premised research on dietary exposure to benzo[a]pyrene, acrylamide, and Nnitrosodimethylamine from common fried and grilled dishes in North Vietnam

Fried and grilled cooking methods and the widespread consumption of certain dishes may expose the population to elevated levels of potentially carcinogenic compounds, such as benzo[a]pyrene (BaP), acrylamide, and N-nitrosodimethylamine (NDMA). This study aims to quickly estimate dietary exposure to these contaminants and assess the associated carcinogenic risk for several common Vietnamese fried and grilled dishes. The concentrations of the target compounds were obtained from the study showed that BaP, NDMA, and acrylamide are the groups of substances of greatest concern. The analytical results of 235 samples of meat and meat products (grilled/fried/smoked), seafood and seafood products (grilled/fried/smoked), processed oils, and potatoes showed that 12 samples detected acrylamide in the range of 5.0 &amp;ndash; 162.0 &amp;micro;g/kg found in grilled/fried dishes and 5.0 &amp;ndash; 4605 &amp;micro;g/kg for fried potatoes. Additionally, 204 samples detected NDMA in all groups in the range of 0.20 &amp;ndash; 15.0 &amp;micro;g/kg, and 27 samples detected BaP in the range of 5.2 &amp;ndash; 88 &amp;micro;g/kg in grilled/roasted food. Combined with information on food consumption patterns to estimate dietary exposure, four age groups were divided into under 6 years old, 6 &amp;ndash; 18 years old, 18 &amp;ndash; 50 years old, and over 50 years old, which showed that the consumption of processed foods by age groups was very different. In particular, the age group from 6 to 50 years old was the group that consumed the most of these foods (14.1 &amp;ndash; 140 g/day). Specifically, up to 94.4% of people interviewed ate fried meat, 88.8% ate fried seafood and 85% ate fried potatoes. Risk characterization using the margin of exposure (MOE) and Cancer Slope Factor approaches indicate that certain dishes, such as grilled/smoked meat and fish, and deep-fried foods, may pose a significant cancer risk to Vietnamese consumers.

Benzo (A) pyrene exposure alters alveolar epithelial and macrophage cells diversity and induces antioxidant responses in lungs

This study was designed to investigate the toxic effects of benzo (a) pyrene (BaP) in the lungs. Mice were repeatedly treated orally with BaP (50 mg/kg body weight, twice a week for four weeks) to induce a tumour. After 4 months of BaP administration, tumours were visible beneath the skin. The histopathological section of the lungs shows congestion of pulmonary blood vessels, alveolar hyperplasia, and concurrent epithelial hyperplasia with infiltrates of inflammatory cells also seen. Thereafter, a single-cell suspension of lung tissues was stained with fluorescently conjugated antibodies for the demarcation of alveolar epithelial (anti-mouse CD74 and podoplanin) and macrophage (F4/80 and CD11b) cells and measured by flow cytometry. The expression of antioxidant genes was assessed by qRT–PCR. The number of alveolar epithelial cells 1 (AEC1) increased, but the number of alveolar epithelial cells 2 (AEC2) and transitional alveolar epithelial cells (TAEC) was significantly decreased in tumour-bearing mice. The proportion of CD11b+ alveolar macrophages (AM) and interstitial macrophages (IM) was increased, but the proportion of F4/80+ AM cells was reduced. The BaP administration significantly increased the ROS production in alveolar cells. The relative expression levels of antioxidant genes (SOD1, catalase, GPX1, and HIF-1α) were increased, but NRF2 expression was decreased in BaP-treated alveolar cells. The expression of anti-inflammatory (NF-κB) was also significantly increased. In conclusion, BaP exposure induced an inflammatory response, altered alveolar epithelial cell and macrophage diversity, and increased antioxidant responses in the lungs.

Perfluorooctane sulfonate (PFOS) and benzo[a]pyrene (BaP) synergistically induce neurotoxicity in C6 rat glioma cells via the activation of neurotransmitter and Cyp1a1-mediated steroid hormone synthesis pathways

Humans are often exposed to complex mixtures of multiple pollutants rather than a single pollutant. However, the combined toxic effects and the molecular mechanism of PFOS and BaP remain poorly understood. In this study, two typical environmental pollutants, perfluorooctane sulfonate acid (PFOS) and benzo[a]pyrene (BaP), were selected to investigate their combined neurotoxic effects on rat C6 glioma cells at environmentally relevant concentrations. The results showed that coexposure to low-dose PFOS and BaP induced greater toxicity (synergistic effect) than did single exposure. PFOS-BaP coexposure had stronger toxic effects on inducing oxidative stress and promoting early apoptosis. Targeted metabolomics confirmed that increased levels of the neurotransmitters 5-hydroxytryptophan, dopamine, tryptophan and serotonin disturb the phenylalanine, tyrosine and tryptophan biosynthesis pathways. Mechanistically, exposure to a low-dose PFOS-BaP binary mixture induces steroid hormone synthesis disorder through the activation of Cyp1a1 and Hsd17b8 (steroid hormone synthesis genes) and Dhcr24 and Dhcr7 (cholesterol synthesis genes). These findings are useful for comprehensively and systematically elucidating the biological safety of PFOS-BaP and its potential threats to human health.

Activation mechanism of persulfate by Fe3C-based materials for efficient benzo-a-pyrene abatement in wastewater: The reversed direct electron transfer from persulfate to contaminants

Herein, an unusual reserved direct electron transfer (r-DET) process from persulfate (PS) to contaminants was observed on the surface of Fe3C with N-doped C shell supported on carbon nanotubes (Fe3C@CN-CNTs). The Fe3C-based materials were synthesized via a facile sol–gel method employing melamine, glucose, FeCl3, and commercial multi-walled CNTs. The activation mechanisms were fully explored with a comparison of Fe3C@CN-CNTs and other Fe3C-based materials for the effective abatement of benzo-a-pyrene (BaP), a typical persistent organic pollutant in industrial wastewater. Electrochemical measurements, zeta potential monitoring, and Mössbauer spectroscopy indicated that the lack of CN shell result the relatively large particle size of Fe3C on Fe3C-CNTs, leading to more negatively charged surface and abundant OH during PS activation. Nevertheless, the superparamagnetic fraction with a fine particle size on the surface of Fe3C@CN and Fe3C@CN-CNTs potentially leads to a more positively charged surface, enhancing the zeta potential of surface adsorbed BaP and benefiting the r-DET. Through r-DET, oxidized PS and reduced BaP formed as intermediates, accelerating the overall degradation of BaP in Fe3C@CN-CNTs/PS. The degradation pathways, cytotoxicity, and operation conditions of BaP degradation by Fe3C@CN-CNTs/PS were thoroughly investigated. Additionally, Fe3C@CN-CNTs were found to promote the nucleophilic reaction between Cl− and PS, producing free chlorine and enhancing BaP degradation efficiency in chloride-containing wastewater. Overall, this study presents a new insight for the PS-based r-DET process and offers a promising approach for treating organically-contaminated wastewater.

Causes of the unremitting high ambient levels of PM10 in a suburban background site in NE Spain

Atmospheric PM10 and benzo(a)pyrene (BaP) concentrations in Manlleu (NE Spain) have remained high from 2008 to 2023, frequently exceeding EU limit/target values, and reaching BaP levels up to six times higher than urban averages in Spain. Furthermore, PM speciation campaigns were carried out in 2013, 2014–2015, 2016–2017 and 2021–2022. Chemical mass closure for autumn-winter showed a consistent PM10 composition for the different PM speciation campaigns, comprising 46–53% organic matter (OM), 18–26% secondary inorganic aerosol (SIA), 13–23% mineral matter (MM), and 5–9% elemental carbon (EC). Trend analysis revealed very light decrease and constant concentrations for PM10 and BaP, respectively over the study period, emphasizing the need for compliance with current and forthcoming EU air quality directives, the last aiming to halve PM10 limit values. Source apportionment of samples of the sporadic campaigns identified biomass burning (BB, 17.5 μg m−3, 48%) and MM and industry (16.3 μg m−3, 44%) as the main autumn-winter PM10 contributors, with high SIA concentrations attributed to several factors, including high ammonia (NH3) emissions. Local topography and meteorological conditions contribute to aggravate PM10 pollution. While metal concentrations have decreased since 2013, suggesting reduced industrial emissions, persistently high OM and EC concentrations indicate ongoing issues with BB emissions from domestic, commercial, and agricultural sources. Online analysis of black carbon (BC) and non-refractory PM1 components during winter 2016–2017 confirmed domestic and commercial BB as the primary sources of the BB contributions. These findings highlight the need of the implementation of more effective measures in reducing BB and agricultural/farming NH3 emissions. This study highlights the relevance of these issues for similar towns, the probable unremitting problem over the last decade, and the necessity of enhanced monitoring in small cities and policy actions to meet air quality standards under the new EU directive.

Assessment of the public health risk caused by exposure to atmospheric emissions from an aluminum plant

Introduction. Aluminum production is accompanied by emissions of pollutants that can negatively affect the environment and public health. The study aims to determine the impact of atmospheric emissions from an aluminum plant on the health of the population of the city of Novokuznetsk based on a risk assessment. Materials and methods. The volume of maximum permissible emissions of the Novokuznetsk Aluminum Plant was used in the work. Experts calculated the maximum and average concentrations of substances at 40 exposure points. The maximum permissible concentrations of substances were determined in accordance with SanPiN 1.2.3685-21. The authors calculated the carcinogenic risk and the risk of non-carcinogenic effects in accordance with the Guidelines 2.1.10.1920-04. They carried out the classification of risk levels based on methodological recommendations 2.1.10.0156-19. 2.1.10. Results. The authors have selected pollutants were for risk assessment: inorganic dust with a SiO2 content of &lt;20%, sulfur dioxide, benz(a)pyrene, hydrogen fluoride, carbon monoxide, nitrogen dioxide, suspended solids, nitrogen oxide, carbon (soot). The maximum concentrations were 0.1–3.77 MPC for inorganic dust (SiO2&lt;20%), 0.1–2.64 MPC for hydrogen fluoride and 0.05–1.74 MPC for sulfur dioxide; average concentrations were up to 9.16 MPC for benz(a)pyrene. The hazard indices for acute exposure are at an acceptable level; For chronic exposures, they correspond to alarming and high levels, reaching the highest value (13.469) at a point located closer to the sources of emissions. Hazard indices for critical organs and systems in acute exposures are at acceptable or minimum (target) levels, in chronic exposures they correspond to alarming and high-risk levels. The respiratory and immune systems are most affected. The total individual carcinogenic risk ranges from 4×10–7 to 8×10–6, without exceeding the upper limit of the permissible risk. Residents of the Kuznetsk district of the city are most affected by emissions. Limitations. The main limitation in the work carried out was the use of calculated concentrations of pollutants for risk assessment without the use of in-kind indicators. Conclusion. Elevated concentrations of pollutants were detected in the atmospheric air of residential areas adjacent to the territory of the aluminum plant, which determine alarming and high levels of non-carcinogenic risk to public health. Ethics. This study did not require the conclusion of the Ethics Committee.

Benzo(a)anthracene Targeting SLC1A5 to Synergistically Enhance PAH Mixture Toxicity.

Human exposure to polycyclic aromatic hydrocarbons (PAHs) as mutagenic and carcinogenic pollutants in the environment often occurs in the form of mixtures. Although the mixture effects of PAHs have been previously recognized, the toxicological mechanisms to explain them still remain quite unclear. This study combined metabolomics and chemical proteomics methods to comprehensively understand the mixture effects of a PAH mixture including benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF), benzo(a)pyrene (BaP), and chrysene (CHR). Among them, BaA has shown a strong synergistic effect with other PAHs. Interestingly, BaA alone is not a potent oxidative stress inducer in liver cells but dose-dependently amplifies oxidative damage caused by the PAH mixture. Global metabolomics analysis results revealed damage to the antioxidant glutathione synthesis, which was caused by the glutamine depletion caused by BaA in the mixture. Subsequently, the label-free chemical proteomics and cellular thermal shift analysis (CETSA) demonstrated that the PAH mixture altered the thermal shift of glutamine transporter SLC1A5. Furthermore, Western blotting and the isothermal titration calorimetry (ITC) interaction measurements showed nanomolar KD values between BaA and SLC1A5. Overall, this study showed that BaA synergistically contributed to PAH mixture induced oxidative damage by targeting SLC1A5 to inhibit glutamate transport into cells, resulting in the inhibition of glutathione synthesis.

Toxic effect of polycyclic aromatic hydrocarbons (PAHs) on co-culture model of human alveolar epithelial cells (A549) and macrophages (THP-1)

Polycyclic aromatic hydrocarbons (PAHs) are particulate matter bound environmental contaminants known to cause adverse effects on human health. The toxicity of carcinogenic PAH such as benzo[a]pyrene (BaP) has been extensively investigated, whereas other PAHs have received less attention. The present work investigated the toxic effects of three less investigated PAHs with distinct molecular weights in comparison to BaP on co-culture model of human epithelial lung cells (A549) and macrophages (THP-1). Due to the involvement of more than one cell type in the response to PAH exposure, the new co-culture model is considered to be suitable for the prediction of undesired toxicological effects of PAHs. To do so, the co-culture was established and exposed to 0–400 µM of phenanthrene (PHE), fluoranthene (FLA), and, benzo [ghi] perylene (BghiP) for 24 h. Subsequently, cytotoxicity, micronucleus formation, and cytokine excretion were analyzed. The results revealed that the viability of A549 cells decreased after being exposed to increasing concentrations of PAHs. The formation of micronuclei in binucleated cells (BNC) was found more frequently in cells treated with PAHs in comparison to the untreated group, indicating the genotoxic effect of these compounds. Moreover, an exposure to PAHs enhanced the pro-inflammatory cytokine, i.e., interleukin-6 secretion, while diminished the anti-inflammatory cytokine, i.e., interleukin-10. In summary, PAHs possess negative effects on A549 and THP-1 co-culture model, implying an adverse effect on human health when coming into contact with these chemicals via respiration.

Benzo(a)pyrene promotes autophagy to impair endometrial decidualization via inhibiting CXCL12/CXCR4 axis

Benzo(a)pyrene (BaP), a pervasive environmental pollutant with endocrine-disrupting properties, has been associated with detrimental effects on pregnancy. During early pregnancy, the endometrial decidualization process is critical for embryo implantation. Abnormal decidualization can lead to implantation failure, aberrant placental formation, and pregnancy loss. We previously revealed that BaP exposure impaired decidualization and implantation in mice, yet the underlying mechanisms remained elusive. Autophagy, a cellular mechanism pivotal for energy and material recycling, contributes to the decidualization process. The chemokine C-X-C motif chemokine ligand 12 (CXCL12), secreted by endometrium stromal cells (ESCs), is involved in regulating endometrial decidualization and autophagy. Therefore, this study aimed to explore the hypothesis that BaP disrupts the decidualization process by interfering with autophagic pathways via the CXCL12/CXCR4 axis during early pregnancy. We found that BaP inhibited CXCL12/CXCR4 expression, and induced autophagy by promoting autophagosome formation, which in turn impaired the decidualization in early pregnant mice uterus and decidual stromal cells (DSCs). Using autophagy inhibitors 3-methyladenine and chloroquine in combination with BaP to treat DSCs, successfully weakened BaP-induced autophagy, and relieved decidual injury. Additionally, activation of CXCL12/CXCR4 by recombinant protein CXCL12 attenuated BaP-induced autophagy, inhibited the PI3K/AKT signal activation caused by BaP, and partly rescued the expression of decidualization-related genes. In summary, this study demonstrates that BaP induces autophagy in DSCs by inhibiting the CXCL12/CXCR4 axis, leading to damage in endometrial decidualization during early pregnancy. The findings provide a critical chemokine-mediated regulatory mechanism involved in embryo implantation and contribute valuable knowledge to the reproductive toxicology of BaP.

Application of tree cores to investigate the historical pollution trends of atmospheric polycyclic aromatic compounds: A case study in a typical coal-contaminated region of China

In this study, 76 polycyclic aromatic compounds (PACs) were detected in air, soil, and tree core samples from Huainan, a typical coal-contaminated region of China. Concentrations of ΣPACs in soil and air samples were 2400 ± 5100 ng/g and 150 ± 63 ng/m3, respectively. Priority PAHs were predominant in both air and soil samples, contributing over 50 % of ΣPACs. Source analysis indicated that PAC contamination in Huainan primarily originated from local coal-related activities. The benzo[a]pyrene (BaP)-toxic equivalent concentrations (TEQBaP) of PACs in the air samples (5.6 ± 5.3 ng/m3) exceeded the threshold of 1 ng/m3. Some PACs, such as benzo[e]pyrene (BeP) and Alk-BaPs, demonstrated significant toxicity and are recommended for consideration as priority pollutants. The historical pollution trends of atmospheric PACs were obtained based on the tree core samples. PAC concentrations in tree core segments showed a strong correlation with atmospheric PM10 levels in Huainan. As air quality has improved in recent years, the PACs concentrations in tree core segments have also decreased. Historical fluctuations of atmospheric PACs were largely attributed to the changes in the gas treatment systems of a nearby coal-fired power plant and adjustments in environmental policies. By integrating trends observed in tree core segments with air concentrations, the historical atmospheric PAC concentrations were extrapolated. The extrapolated results showed similar concentration levels and trends when compared with historical data from other studies in China. Thus, tree cores can not only reflect the historical trends of atmospheric PACs with high temporal precision but also are feasible for extrapolating historical concentrations of airborne PACs.

Possible Causes of Extreme Variation of Benzo[a]pyrene Acute Toxicity Test on Daphnia magna.

There are enormous differences in benzo[a]pyrene (BaP) acute toxicity tests on Daphnia magna, according to previous publications. The explanations of the reasons for this extreme variation are necessary. In this context, the acute toxicity tests of different experiment conditions (light/dark, culture medium, and solvent) were conducted on Daphnia magna with BaP as the toxicant of concern. Based on the experiments above, molecular dynamics (MD) simulations were employed to investigate the mechanisms of action. According to our results, the significant influence of light exposure on the acute toxicity test of BaP (p < 0.05) on D. magna was recorded. On the basis of the MD simulations, it was possible that BaP may not affect the normal operation of Superoxide Dismutase and Catalase directly, and it could be quickly transferred from the body through Glutathione S-transferase and Cytochromes P450. Therefore, when exposed to light, the oxidative stress process intensifies, causing damage to Daphnia magna. Apparently, the ecotoxicity tests based on inhibition for D. magna cannot adequately reflect the toxic effects of BaP.

The key results of studies of benzo(a)pyrene in natural and man-made environments of the Southern Baikal region (2016–2024)

The study aims to provide a retrospective review of the results of studies of benz(a)pyrene in the natural and man-made environments of the Southern Baikal region. The study was conducted with staff, students, and postgraduates at the Department of Industrial Ecology and Railways of the Institute of Subsoil Use of Irkutsk National Research Technical University in 2016-2024. The article is devoted to the 75th anniversary of the department. The atmospheric air in the cities of Irkutsk and Krasnoyarsk regions was assessed based on the results of monitoring of the content of benzо(a)pyrene. Its carcinogenic risks to public health were determined. The results of the systematic study of the sources of emissions into the atmosphere of benzо(a)pyrene and its analogues of polycyclic aromatic hydrocarbons were analyzed. Anthropogenic and man-made (aluminum production, low-power heat sources, highways) and natural (forest fires) sources of benzо(a)pyrene release were identified by assessing its mass load. The indicators of sources of atmospheric pollution - snow cover, soils, plants - were identified. Correlations between atmospheric air pollution and health (neoplasms) of the Irkutsk region population were determined found. The distribution of benzо(a)pyrene in the systems of conjugated objects of the biosphere was studied: “source of emissions - atmospheric air - snow cover”, “soil - plant”, “water - hydrobionts”. Patterns indicating a new source of atmospheric pollution with carcinogenic polycyclic aromatic hydrocarbons - natural fires, which can affect the morbidity of the population of the Southern Baikal region - were obtained.