Aromatic Hydrocarbons Research Articles

Ethanol conversion to hydrocarbons over Sn-doped H-ZSM-5 zeolite catalysts

Sn-based zeolite have been prepared by incipient wetness impregnation by studying the role of the starting precursor either Sn(II) or Sn(IV) chlorides. Catalysts have been deeply characterized through XRD, FT-IR, UV-vis NIR, SEM-EDXS, FE-SEM-EDXS, and IR of probe molecules i.e. pyridine and CO by also investigating the reaction at the surface in static conditions. As well catalytic activity has been carried out by investigating the role of GHSV that has been varied between 2700-8500 h-1, obtaining linear variation of product distribution as a function of contact time. Small amounts of Sn improve the catalytic activity of H-ZSM-5 zeolite in converting ethanol to higher hydrocarbons. In particular, the addition of Sn4+ ions increases the conversion of ethanol to C6-C8 aromatic hydrocarbons up to a very interesting 34% selectivity at 100% ethanol conversion. In fact, bioethanol conversion over Sn-H-ZSM-5 zeolite represents a potentially interesting way to produce a high-octane biogasoline, as well as aromatic (BTX) cut useful as a renewable intermediate in future biorefinery-derived processes. It is proposed that ethylene, the main product, is the key intermediate in the acid-catalysed route, and Sn-ions are favoring the cyclization and dehydrogenation of ethylene-derived oligomers.

Utilizing a synergistic strategy that combines electromagnetic and chemical enhancement to analyze the SERS effect of the Fe3O4@GO@Ag on PAHs detection

A comprehensive understanding of the enhancement mechanism of the substrate material is crucial to ensure the repeatability and functionality of SERS detection technology. Therefore, this study introduces a theoretical analysis method that integrates electromagnetic and chemical enhancement to achieve a comprehensive understanding of the SERS effect on the magnetic composite substrate. The visual model is employed in this study to comprehensively analyze and illustrate the electric field enhancement and optical effects of composite substrate materials. The study also elucidated the adsorption and charge transfer between the substrate material and target molecules. Based on this theory, Fe3O4@GO@Ag material was prepared and used to detect hydrophobic organic molecules such as polycyclic aromatic hydrocarbons (PAHs), with a concentration as low as 0.5 nM. This study comprehensively analyzed the SERS enhancement effect of the composite substrate for the first time, and prepared a magnetic composite substrate material for the detection of hydrophobic organic molecules, opening up a new avenue for theoretical guidance and experimental exploration in SERS detection and analysis.

Microbial electrochemical enhanced composting of sludge and kitchen waste: Electricity generation, composting efficiency and health risk assessment for land use

To realize the energy and resource utilization from organic solid waste, a two-phase microbial desalination cell (TPMDC) was constructed using dewatered sludge and kitchen waste as the anode substrate. The performance of electricity generation and composting efficacy was investigated, along with a comprehensive assessment of the potential health risks associated with the land use of the resulting mixed compost products. Experimental outcomes revealed a maximum open-circuit voltage of 0.893 ± 0.005 V and a maximum volumetric power density of 0.797 ± 0.009 W/m³. After 90 days of composting enhanced by microbial electrochemistry, a significant organic matter removal rate of 31.13 ± 0.44 % was obtained, and the anode substrate electric conductivity was reduced by 30.02 ± 0.04 % based on the anode desalination. Simultaneously, there was an increase in the content of available nitrogen, phosphorus, and potassium, as well as an improvement in the seed germination index. The forms of heavy metals shifted from bioavailable to stable residual states. The non-carcinogenic hazard index (HI) values for heavy metals and polycyclic aromatic hydrocarbons (PAHs) during the land use of compost products were less than 1, and the total carcinogenic risk (TCR) values for heavy metals and PAHs were below the acceptable threshold of 10−4. The occupational population risk of infection from five pathogens was higher than that of the general public, with all risk values ranging from 8.67 × 10−8 to 1, where the highest risk was attributed to occupational exposure to Legionella. These outcomes demonstrated that the mixture of dewatered sludge and kitchen waste was an appropriate anode substrate to enhance TPMDC stability for electricity generation, and its compost products have promising land use suitability and acceptable land use risk, which will provide important guidance for the safe treatment and disposal of organic solid waste.

A vortex-assisted MSPD method for the extraction of Polycyclic Aromatic Hydrocarbons from shrimp with determination by GC-MS/MS

Polycyclic Aromatic Hydrocarbons (PAHs) are organic compounds with two or more condensed aromatic rings, formed from incomplete organic matter combustion. PAHs pose potential health risks due to their carcinogenic and mutagenic properties, accumulating in edible tissues of aquatic organisms, such as shrimp, which is extensively produced in the southern region of Rio Grande do Sul state (Brazil) and it is the most consumed seafood globally. Therefore, this study aimed to optimize and validate an analytical method for extracting 16 priority PAHs from shrimp samples using Vortex-Assisted Matrix Solid-Phase Dispersion (VA-MSPD) with determination by Gas Chromatography Tandem Mass Spectrometry (GC-MS/MS). The optimized method, which uses a reused solid support, was validated according to INMETRO and SANTE guidelines. PAHs demonstrated adequate linearity with correlation coefficients > 0.99. The matrix effect was assessed, and 12 out of the 16 PAHs showed a matrix effect of less than ±20%. The method's quantification limits ranged from 6.67 to 33.35 ng g-1. Accuracy and precision showed recovery values ranging from 55 to 115% with relative standard deviation (RSD) lower than 17% for all PAHs. In the applicability, 11 PAHs were detected, such as benzo[a]pyrene and benzo[b]fluoranthene, and the ∑PAHs ranged from 25.14 to 79.52 ng g-1, confirming the environmental contamination in the region and the need for monitoring these contaminants in shrimp destined for human consumption.

Legacy and novel contaminants in surface sediments of Admiralty Bay, Antarctica Peninsula

Despite being one of the most remote areas on the planet, the Antarctic continent is subject to anthropogenic influences. The presence of various groups of contaminants, including persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs), has been documented in the region over the past decades. However, a significant knowledge gap remains regarding the detection of new pollutants, such as emerging contaminants (ECs), in Antarctic coastal environments. This study analyzed the occurrence and levels of selected POPs, PAHs, ECs in surface sediments from Admiralty Bay, Antarctica Peninsula. Non-target screening was employed to identify potential novel contaminants in the region. Samples (n = 17) were extracted using an accelerated solvent extraction (ASE) system and instrumental analyses were performed using gas chromatography coupled to a triple-quadrupole mass spectrometer (GC/MS-MS). Regarding regulated contaminants, concentrations of Σ5PCBs ranged from <LOD to 0.5 ng g−1, while Σ16PAHs ranged from 2.6 to 617.4 ng g−1. These compounds were predominant in the Martel inlet, suggesting influences of local input sources, especially for PAHs. ECs were detected in some sites of the Ezcurra and Martel inlets, especially nearby the Brazilian and Polish research stations. The UV filters homosalate (0.3 to 251.3 ng g−1) and octocrylene (0.7 to 93.8 ng g−1) were the most abundant EC, followed by TPP (0.1 to 87.4 ng g−1) and galaxolide (0.2 to 55.0 ng g−1). Applying non-target analysis, phthalates, and the fragrance OTNE (octahydro-tetramethyl-naphthalenyl-ethanone) were identified for the first time in Antarctic sediments. The data highlights the contribution of human activities in the region, possibly through wastewater effluents. This study provides data on the current levels of PAHs and POPs in the region, which are steadily decreasing over the years.

Baseline polycyclic aromatic hydrocarbon maternal transfer data in Lesser Numbfish Narcine brasiliensis (Elasmobranchii: Batoidea) from an impacted estuary in Southeastern Brazil

Maternal offloading of polycyclic aromatic hydrocarbons (PAHs) poses a significant exposure route for developing embryos, with implications for subsequent generations. Despite known developmental effects regarding fish physiology and behavior, maternal PAH transfer assessments in elasmobranchii are still lacking. This study investigated PAH contamination and maternal transfer in one female Lesser Numbfish (Narcine brasiliensis) electric ray and seven embryos for the first time. Naphthalene was identified as the predominant low molecular weight PAH, and dibenzo[a,h]anthracene was the most abundant high molecular weight compound. Most embryos exhibited some level of PAH exposure, with varying accumulation patterns potentially influenced by size, developmental stage, and yolk absorption rates. Further investigation is warranted to understand the impacts of PAH maternal offloading on elasmobranchii uterine contents and embryos.

Experimental Determination of the Unusual CH Stretch Frequency of Protonated Fullerenes

We report experimental values for the CH stretch frequencies of the protonated fullerenes C60H+ and C70H+. Anharmonic frequency calculations at the B3LYP/6-31G level of theory, which are independent of empirical scaling factors, reproduce the experimental values to within approximately 5 cm−1. Scaling theoretical harmonic frequencies by applying factors derived for polycyclic aromatic hydrocarbons deviate significantly from the experimentally measured frequency. We attribute this deviation to the unusual hydrocarbon structure that affects the degree of anharmonicity of the CH stretch. This result allows us to propose an original, specific scaling factor of 0.9524 to correct harmonic frequencies of CH stretches of protonated fullerenes calculated at the B3LYP/6-311 + G(d,p) level of theory. The special spectral position of the protonated fullerene CH stretch bands makes it a diagnostic marker that may aid in their detection in the interstellar medium.

Assessment of polycyclic aromatic hydrocarbon (PAH) levels and health risks in kitchen dust from wood, kerosene, and gas cooking systems in Cumilla, Bangladesh

This study investigates the presence of polycyclic aromatic hydrocarbons (PAHs) in kitchen dust from households in the Cumilla District of Bangladesh, utilizing three different cooking systems: wood, kerosene, and gas. Sixty dust samples were collected from various kitchen surfaces and analyzed for 18 PAH compounds. The extraction and analysis of PAHs were performed using gas chromatography-mass spectrometry (GC-MS) with selective ion monitoring (SIM) mode. The results indicated significant variations in PAH concentrations across different cooking systems, with the highest levels observed in kitchens using wood stoves, followed by kerosene and gas stoves. Diagnostic ratios were used to identify the sources of PAHs, revealing a combination of pyrogenic and petrogenic origins. Health risk assessments, including Incremental Lifetime Cancer Risk (ILCR) and Hazard Index (HI), were conducted to evaluate the potential risks associated with PAH exposure. The findings demonstrated a higher carcinogenic risk associated with wood stove systems, while kerosene and gas systems posed comparatively lower risks. The study's findings have practical implications for public health and policy development, as they underscore the need for continuous monitoring of indoor PAH levels and the development of policies to mitigate exposure, highlighting the critical importance of addressing indoor pollution to ensure public health safety.

Paleoclimate, paleoenvironment, and human impact over the last 400 years based on lipid biomarkers from Lake Höglwörth, Germany

Lipid biomarkers are valuable proxies for reconstructing paleoclimate and paleoenvironmental changes as well as human impact. However, little attention has been paid on evaluating how the combination of biomarkers can be used to reconstruct various aspects of local paleoenvironmental conditions. This study presents a suite of lipid biomarker records from a sediment core from Lake Höglwörth, southern Germany, covering the past 400 years. Compound-specific hydrogen isotopic compositions (δD) of terrestrial n-alkanes (n-C29-alkane) and n-alkanoic acids (n-C30-acid) indicate minor changes in isotopic composition of precipitation. The δD of n-C22-acid is interpreted to record the isotopic composition of the lake water and evaporative enrichment, which drops after 1700 CE, coinciding with the construction of a mill and the related rerouting of a creek into Lake Höglwörth. The δD of n-C25-alkane is also enriched but decoupled from the reconstructed isotopic composition of precipitation and lake water. Therefore, we suggest that δD of n-C25-alkane reflects the leaf water isotopic composition of Sphagnum, which is present in the catchment and undergoes transpirative enrichment. Both short-chain compounds have become more enriched over the last century, maybe related to increasing temperature associated with anthropogenic climate warming. The faecal biomarkers record the changes in human population, partly related to the history of the local Monastery, the World Wars I and II as well as the intensive farming after the mid-20th century. Polycyclic aromatic hydrocarbons (PAHs) reveal a significant change in combustion activities associated with human activities such as the industrial revolution, biomass burning, and environmental cleanup as well as the implementation of emission standards. Our study demonstrates that the combination of plant wax compounds, faecal biomarkers, and PAHs from lacustrine sediment serves as a valuable tool to reconstruct and distinguish various aspects of paleoclimate and paleoenvironmental changes including human impacts.

FEAST: Feedback in Emerging extragAlactic Star ClusTers: JWST Spots Polycyclic Aromatic Hydrocarbon Destruction in NGC 628 during the Emerging Phase of Star Formation

We investigate the emergence phase of young star clusters in the nearby spiral galaxy NGC 628. We use JWST NIRCam and MIRI observations to create spatially resolved maps of the Paα 1.87 μm and Brα 4.05 μm hydrogen recombination lines, as well as 3.3 and 7.7 μm emission from polycyclic aromatic hydrocarbons (PAHs). We extract 953 compact H ii regions and analyze the PAH emission and morphology at ∼10 pc scales in the associated photodissociation regions. While H ii regions remain compact, radial profiles help us to define three PAH morphological classes: compact (∼42%), extended (∼34%), and open (∼24%). The majority of compact and extended PAH morphologies are associated with very young star clusters (<5 Myr), while open PAH morphologies are mainly associated with star clusters older than 3 Myr. We observe a general decrease in the 3.3 and 7.7 μm PAH band emission as a function of cluster age, while their ratio remains constant with age out to 10 Myr and morphological class. The recovered PAH3.3μm/PAH7.7μm ratio is lower than values reported in the literature for reference models that consider neutral and ionized PAH populations and analyses conducted at galactic physical scales. The 3.3 and 7.7 μm bands are typically associated with neutral and ionized PAHs, respectively. While we expected neutral PAHs to be suppressed in proximity to an ionizing source, the constant PAH3.3μm/PAH7.7μm ratio would indicate that both families of molecules disrupt at similar rates in proximity to H ii regions.

Semi-diurnal distribution of polycyclic aromatic hydrocarbons bound to PM2.5 and PM0.1 during pollution episode in the urban area of Hanoi.

Every year, Hanoi suffers from several episodes (periods with daily concentration of PM2.5 higher than 50µgm-3 during at least two consecutive days). These episodes are of health concern because of the high concentration of PM2.5 and/or PM0.1 and the presence of PM-bound toxic components, such as, PAHs. In this study, the concentrations of PAHs bound to PM2.5 and PM0.1 in night-time and day-time samples during episode and non-episode periods in December 2021 were determined. The concentrations of PAHs bound to PM2.5 were found to increase significantly from day-time samples of 3.24 ± 0.83ngm-3 to night-time samples of 10.8 ± 4.45ngm-3 in episode periods. However, PAHs bound to PM0.1 increased slightly from day-time samples of 0.58 ± 0.12ngm-3 to night-time samples of 0.89 ± 0.30ngm-3 in episode periods. Diagnostic ratios of PAHs indicate that biomass/coal combustion andvehicular emissionare the primary sources of PAHs. The incremental lifetime cancer risk was estimated to vary from 8.7E-09 to 2.5E-08 for children and 6.7E-08 to 2.2E-07 for adults, respectively. Accordingly, loss of life expectancy was estimated at 0.11min and 0.82min for children and adults, respectively. These findings imply that the carcinogenic impact induced by PAHs via inhalation is negligible during the episode period.

Insights into relationship between microbial community-induced polycyclic aromatic hydrocarbons degradation and soluble organic matter transformation during vermiculite-amended sewage sludge composting

Vermiculite is a natural clay mineral with unique properties that are widely used in plant cultivation, soil remediation, and solid waste management. This study investigated the relationship between microbial community-induced polycyclic aromatic hydrocarbons (PAHs) degradation and dissolved organic matter (DOM) transformation during vermiculite-amended composting of sewage sludge. Four treatments with varying vermiculite percent compositions, 0%, 1%, 5%, and 10%, mixed with initial mix waste, were designed and then composted for 33 days. The results showed that the addition of 1% vermiculite caused the highest losses of 82.19%, 52.98%, and 69.00% for LMW-PAHs (2-3 rings), HMW-PAHs (4-6 rings), and total PAHs respectively compared to other treatments. Spectral and community analyses revealed that 1% vermiculite enhanced the PAHs losses by functional networking of key genera and promoting the aromatization and humification of DOM to format the micelles with PAHs. The transformation and utilization of DOM driven by key genera Acinetobacter, Ochrobactrum, Pseudoxanthomonas, and Bacillus were the important impact factors for the losses of PAHs. Finally, this study provides new insights and a guide for applying vermiculite to sludge composting for PAHs removal.

Enhancing bioremediation of petroleum-contaminated soil by sophorolipids-modified biochar: Combined metagenomic and metabolomic analyses

In this study, sophorolipids (SLs)-modified biochar (BC-SLs) was used to enhance the bioremediation of petroleum hydrocarbons (PHs) contaminated soil. The biodegradation rate of petroleum hydrocarbons (PHs) by BC-SLs and BC treatments were 62.86 % and 52.64 % after 60 days of remediation experiments, respectively, higher than non-biochar treatment group (24.09 %). The metagenomic analysis showed that the abundance of petroleum-degrading bacteria Actinobacteria and Proteobacteria were increased by 3.8 % and 5.3 %, respectively in BC-SLs treatment, and the abundance of functional genes for PHs degradation, such as alkB, nidA and pcaG, were significantly increased by 12.85 %, 30.08 % and 21.01 %, respectively. The metabolomic analysis showed that BC-SLs facilitated the metabolic process of PHs, the microbial metabolism of petroleum hydrocarbons (PHs) became more active. Fatty acid degradation and polycyclic aromatic hydrocarbons (PAHs) degradation were up-regulated, indicating the promoting effect of the BC-SLs for PHs metabolism. The combined metagenomic and metabolomic analysis demonstrated the strong positive correlations between PHs metabolites and PHs-degrading bacteria, such as lauric acid vs. Actinobacteria, benzoic vs. Proteobacteria. The strong positive correlations between PHs metabolites and PHs-degrading genes were also observed, such as o-ehyltoluene vs. nahD, 4-isopropylbenzoic acid vs. etbAa. The modification of biochar with SLs increased the oxygen-containing functional groups on the surface of biochar. Meanwhile, the emulsification and solubilization of SLs promoted the bioavailability of PHs. The effects of BC-SLs on the nitrogen cycle during PHs remediation showed that it facilitated the accumulation of nitrogen-fixing genes, promoted nitrification but inhibited denitrification process. This study confirms that the application of BC-SLs is an effective remediation of PHs contamination and a sustainable method for controlling agricultural waste resources.

Polycyclic aromatic hydrocarbon and its adducts in peripheral blood: Gene and environment interaction among Chinese population

BackgroundBenzo[a]pyrene (B[a]P) is the most widely concerned polycyclic aromatic hydrocarbons (PAHs), which metabolizes benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) in vivo to produce carcinogenic effect on the body. Currently, there is limited research on the role of the variation of metabolic enzymes in this process. MethodsWe carried out a study including 752 participants, measured the concentrations of 16 kinds PAHs in both particle and gaseous phase, urinary PAHs metabolites, leukocyte BPDE-DNA adducts and serum BPDE- Albumin (BPDE-Alb) adduct, and calculated daily intake dose (DID) to assess the cumulative exposure of PAHs. We conducted single nucleotide polymorphism (SNP) sites of metabolic enzymes, explored the exposure–response relationship between the levels of exposure and BPDE adducts using multiple linear regression models. ResultOur results indicated that an interquartile range (IQR) increase in B[a]P, PAHs, BaPeq, 1-hydroxypyrene (1-OHP), 1-hydroxynaphthalene (1-OHNap) and 2-hydroxynaphthalene (2-OHNap) were associated with 26.53 %, 24.24 %, 28.15 %, 39.15 %, 12.85 % and 14.09 % increase in leukocyte BPDE-DNA adducts (all P < 0.05). However, there was no significant correlation between exposure with serum BPDE-Alb adduct (P > 0.05). Besides, we also found the polymorphism of CYP1A1(Gly45Asp), CYP2C9 (Ile359Leu), and UGT1A1(downstream) may affect BPDE adducts level. ConclusionOur results indicates that leukocyte BPDE-DNA adduct could better reflect the exposure to PAHs. Furthermore, the polymorphism of CYP1A1, CYP2C9 and UGT1A1affected the content of BPDE adduct.

Foliar spraying of different size SiO2 nanoparticles affected phenanthrene accumulation in amaranth (Amaranthus tricolor L.): A metabolomics insight

Silica nanoparticles (nSiO2) have attracted considerable attention in agricultural practices. However, their effects on polycyclic aromatic hydrocarbon (PAH) accumulation in plants remain largely unknown. Thus, this issue was tracked here with a 30-d pot experiment with foliar spraying different sizes of nSiO2 (100 mg L-1, 10 mL) on Amaranthus tricolor L. (amaranth). Results showed that 30 nm and 100 nm nSiO2 increased phenanthrene (PHE) contents in amaranth leaves by 242% ± 88.4% and 158% ± 29.6%, respectively, which was more significant than 2 µm particles (96.0% ± 29.2%). Metabolomics indicated that compared to nSiO2, 2 µm SiO2 more significantly boosted oxidative defense in amaranth leaves, enhanced cell membrane fluidity, and upregulated amino acid metabolism, glycolysis, and gluconeogenesis. In addition, the upregulation of discriminating metabolites was the most significant in 2 µm SiO2-treatment, followed by 100 nm and 30 nm. This is mainly because nSiO2 promoted amaranth growth and decreased average PHE content per unit biomass, namely “dilute effect”. Thus, slighter metabolic disturbances were observed in 30 nm and 100 nm SiO2-treated group. The present study revealed the possibility of PAHs accumulation enhancement in vegetables with nSiO2 foliar spayed. The results of this study provide theoretical guidance regarding to particle size selection for the safe agricultural application of nSiO2 in PAHs-contaminated areas.

Elimination of positive and negative sampling artifacts in particulate organic carbon and PAHs using multi-sorbent coated and uncoated denuders

Within the scope of this study, two equivalent PM2.5 samplers were designed and developed to eliminate sampling artifacts in the results of atmospheric particulate organic carbon (OC) and particulate polycyclic aromatic hydrocarbons (PAH) caused by volatile organic compounds (VOCs) and gas phase PAH compounds, respectively. A mass loss of less than 10% due to the denuders was observed. Study results showed that if an impregnated denuder is not used, the results of atmospheric particle OC concentrations will be reported with higher values due to positive errors of 53.2 ± 7.23% (median: 52.00%) on average. It was observed that the total error (net error) was still positive, but decreased to an average of 35.1 ± 16.8% (median: 31.0%) after including the negative errors quantified from the backup filter into the calculation. In cases where denuders were not used in the sampling, it was observed that the results with positive errors of 41.0 ± 14.6% (median: 33.8%) on average would be obtained for the total PAHs. Ozone-induced negative interference was the highest in Acenapthylene (28%), followed by Fluoranthane (20%), Phenanthrene (18%), and 15% for Np and Benzo[g,h,i]perylene compounds, relative to their medians. Negative errors of 10% or less were found in all other individual PAH compounds.

Effect of UV exposure and natural aging on the in vitro PAHs bioaccessibility associated with tire wear particles in soil

Tire wear particles (TWP), as an emerging type of microplastics, are a significant source of contaminants in roadside soils due to their high concentration of pollutants, including polycyclic aromatic hydrocarbons (PAHs). This study explored the impact of ultraviolet (UV) exposure and natural aging on the in vitro bioaccessibility of PAHs associated with TWP in soil on a China-wide scale. Our findings suggested that UV exposure amplified the negative charge of TWP by 75 % and increased the hydrophobic groups on the particle surface. The bioaccessibility of 3- and 4-ring PAHs in TWP was significantly (p < 0.05) heightened by UV exposure. After 20 types of soils containing 2 % UV-exposed TWP underwent natural aging, the bioaccessibility of PAHs saw a significant decrease (p < 0.05) to 16–48 %, compared to 28–96 % in the unaged group. Soil pH and electrical conductivity (EC) were the two primary soil properties positively influencing the reduction of in vitro PAHs concentration and PAHs bioaccessibility. According to the prediction results, soils in southern China presented the highest potential region for the release of bioaccessible PAHs from TWP, highlighting the regional specificity of environmental impact. Our study provides valuable insights into the biological impact of PAHs associated with TWP on a regional scale, and offers scientific evidence for targeted soil risk management strategies.

Healthy lifestyles ameliorate an increased risk of periodontitis associated with polycyclic aromatic hydrocarbons

The risk of chronic inflammatory diseases has been linked to exposure to polycyclic aromatic hydrocarbons (PAHs). However, limited data are available regarding their impact on periodontitis. This study aims to explore the association between PAHs and periodontitis while also evaluating the potential modifying effects of healthy lifestyles. We included 17,031 participants from the US National Health and Nutrition Examination Survey (NHANES, 2001–2004 and 2009–2014). A meta-analysis-based environment-wide association study (EWAS) was adopted to identify environmental chemicals for the mean probing pocket depth (PPD) and the mean attachment loss (AL). PAHs were further evaluated concerning the cross-sectional association with Mod/Sev periodontitis using multivariable logistic regression models. Moreover, healthy lifestyle scores were estimated to assess their modifying effect on the PAH–periodontitis association. EWAS analysis identified several urinary PAH metabolites as significant risk factors for the mean PPD and AL (false discovery rate <0.05, Q > 0.05). Periodontitis severity was positively associated with eight individual and total PAH concentrations. Stratifying the participants in terms of healthy lifestyle scores did not reveal any association in the healthy group. Moreover, the association weakened in never-smokers and individuals with sufficient physical activity and normal weight. PAH exposure was a risk factor for periodontitis. A healthier lifestyle was observed to offset the risk potentials of PAHs for periodontitis. Smoking cessation, physical activity, and weight loss might be recommended as a healthy lifestyle strategy for ameliorating PAH-related periodontitis.

Assessment of the contamination by carbonaceous anthropogenic particulates and polycyclic aromatic hydrocarbons (PAHs) concentration in recreational areas of an estuary heavily industrialized in Northern Spain

The commercial management of coal and its by-products has the potential to negatively impact natural coastal environments. The coal conversion processes and coke production are sources of polycyclic aromatic hydrocarbons (PAHs) emissions that also contribute to the pollution of those aquatic environments. This research assesses the contamination by carbonaceous anthropogenic particles and by polycyclic aromatic hydrocarbons of some recreational sites (Arañón, Peña del Caballo and San Balandrán area) located in the Avilés' estuary, an area in Northern Spain that has been heavily industrialized since the 1950s. The results obtained indicate a low concentration of solid organic anthropogenic particles in the intertidal sediments of the recreational sites in the estuary, probably due to the protective measures set in place at the facilities managing bulk coal and coke, which prevents the dispersion of coal dust (and other materials) as well as the eventual failure into the estuary. The characteristics of 16 priority pollutants PAHs analyzed in two recreational sites of the estuary (San Balandrán area), their distribution by aromatic ring number together with their diagnostic ratios demonstrate a pyrogenic nature with a main source from processes of coal and coke conversion (including combustion) in the facilities around the estuary. Some contribution of PAHs derived from petroleum cannot be ruled out. This contamination by PAHS is constant and sustained over time. The majority of the considered PAHs are well above the Spanish Generic Reference Level, (GRL) established for “protection of ecosystems with aquatic organisms”, and only a few of them are notably above the corresponding Spanish GRL established for “other uses of land”, which should include lands for recreational activities. The analysis of the potential toxicity risk of PAHs for human health and the organisms of the aquatic ecosystem suggests a relatively low toxicity risk to very high toxicity risk in the San Balandrán environment according to the concentration and distribution trend of PAHs identified in this area. This trend is dependent on the coastal dynamics and the protection level of the site, which also affect the distribution of the anthropogenic carbonaceous particulates in the same way.

Persistent organic pollutants disrupt the oxidant/antioxidant balance of INS-1E pancreatic β-cells causing their physiological dysfunctions

BackgroundPersistent organic pollutants (POPs) have emerged as potent diabetogenic agents, but their mechanisms of action remain poorly identified. ObjectivesIn this study, we aim to determine the mechanisms regulating the damaging effects of POPs in pancreatic β-cells, which have a central role in the development of diabetes. MethodsWe treated INS-1E pancreatic β-cells with PCB-153, p,p’-DDE, PCB-126, or TCDD at doses ranging from 1 × 10-15to 5 × 10-6M. We measured insulin content and secretion, cell viability and assessed the mRNA expression of the xenobiotic nuclear receptors Nr1i2 and Nr1i3, and the aryl hydrocarbon receptor (Ahr). In addition, we evaluated the antioxidant defense and production of reactive oxygen species (ROS). Finally, we studied the ability of the antioxidant N-acetyl-L-cysteine (NAC) to counteract the effects of POPs in INS-1E cells. ResultsWhen exposed to environmental POP levels, INS-1E cells had impaired production and secretion of insulin. These defects were observed for all tested POPs and were paralleled by reduced Ins1 and Ins2 mRNA expression. While POP treatment for 3 days did not affect INS-1E cell viability, longer treatment progressively killed the cells. Furthermore, we found that the xenobiotic detoxification machinery is poorly expressed in the INS-1E cells, as characterized by the absence of Nr1i2 and Nr1i3 and their respective downstream targets Cyp3a1/Cyp3a2 and Cyp2b1/Cyp2b3, and the weak functionality of the Ahr/Cyp1a1 signaling. Interestingly, POPs dysregulated key antioxidant enzymes such as glutathione peroxidases, peroxiredoxins, thioredoxins, and catalases. In parallel, the production of intracellular ROS, including superoxide anion (O2•−) and hydrogen peroxide (H2O2), was increased by POP exposure. Improving the oxidant scavenging capacity of INS-1E cells by NAC treatment restored the production and secretion of insulin. ConclusionBy promoting oxidative stress and impairing the ability of INS-1E cells to produce and secrete insulin, this study reveals how POPs can mechanistically act as diabetogenic agents, and provides new scientific evidence supporting the concept that POPs are fueling the diabetes epidemics.