Polycyclic Aromatic Hydrocarbons Mixtures Research Articles

Preparation of N and O doped coal tar pitch based porous carbon for supercapacitor electrode

Coal tar pitch (CTP) is mainly composed of a mixture of polycyclic aromatic hydrocarbons, is almost hydrophobic, and has a low heteroatom content, which limits its surface function. During carbonization, it is prone to condensation and difficult to form pore structures, resulting in poor electrochemical performance for carbon electrode materials. Herein, nitrogen (N) and oxygen (O) doped hierarchical porous carbon (C-ANOCTP) was prepared by HNO3 oxidation and KOH activation using CTP as carbon precursor. The oxidation of HNO3 remarkably increases the hydrophilic functional groups containing N and O on the surface of CTP, improves the hydrophilicity of CTP surface, facilitates the activation process of KOH, promotes the development of carbon material pore structure and the generation of active sites, as well as the formation of defect structures. The specific surface area of C-ANOCTP obtained is 1130 m2/g, with O content of 10.29 at% and N content of 2.37 at%. The specific capacitance of C-ANOCTP in a three-electrode system with 6 M KOH electrolyte is as high as 410.51 F/g at 0.5 A/g. A symmetric supercapacitor is assembled in a 6 M KOH electrolyte using C-ANOCTP as electrode. When the power density is 25 W/kg, the energy density is 10.24 Wh/kg. After 10,000 cycles, the capacitance retention rate is still 90.03% and the coulomb efficiency is 100%. The high N and O content of porous carbon is prepared by simple HNO3 oxidation synergistic KOH activation and low temperature carbonization, which shows excellent electrochemical properties in supercapacitors, making CTP an ideal candidate material for high energy density supercapacitors.

Associations of polycyclic aromatic hydrocarbons mixtures with cardiovascular diseases mortality and all-cause mortality and the mediation role of phenotypic ageing: A time-to-event analysis

The associations of polycyclic aromatic hydrocarbons (PAHs) with cardiovascular diseases (CVDs) and all-cause mortality are unclear, especially the joint effects of PAHs exposure. Meanwhile, no studies have examined the effect of phenotypic ageing on the relationship between PAHs and mortality. Therefore, this study aimed to investigate the independent and joint associations between PAHs and CVDs, all-cause mortality, and assess whether phenotypic age acceleration (PhenoAgeAccel) mediate this relationship. We retrospectively collected data of 11,983 adults from the National Health and Nutrition Examination Survey database. Firstly, Cox proportional hazards regression and restricted cubic splines were applied to evaluate the independent association of single PAH on mortality. Further, time-dependent Probit extension of Bayesian Kernel Machine Regression and quantile-based g-computation models were conducted to test the joint effect of PAHs on mortality. Then, difference method was used to calculate the mediation proportion of PhenoAgeAccel in the association between PAHs and mortality. Our results revealed that joint exposure to PAHs showed positive association with CVDs and all-cause mortality. By controlling potential confounders, 1-Hydroxynapthalene (1-NAP) (HR = 1.24, P = 0.035) and 2-Hydroxyfluorene (2-FLU) (HR = 1.25, P < 0.001) showed positive association with CVDs mortality, and they were the top 2 predictors (weight: 0.82 for 1-NAP, 0.14 for 2-FLU) of CVDs mortality. 1-NAP (HR = 1.15, P < 0.001) and 2-FLU (HR = 1.13, P < 0.001) also showed positive association with all-cause mortality, and they were also the top 2 predictors of all-cause mortality (weight: 0.66 for 1-NAP, 0.34 for 2-FLU). PhenoAgeAccel mediated the relationship between 1-NAP, 2-FLU and CVDs, all-cause mortality, with a mediation proportion of 10.00 % to 24.90 % (P < 0.05). Specifically, the components of PhenoAgeAccel including C-reactive protein, lymphocyte percent, white blood cell count, red cell distribution width, and mean cell volume were the main contributors of mediation effects. Our study highlights the hazards of joint exposure of PAHs and the importance of phenotypic ageing on the relationship between PAHs and mortality.

Can environmental factors increase oxidative responses in fish exposed to polycyclic aromatic hydrocarbons (PAHs)?

Relations among polycyclic aromatic hydrocarbons (PAHs), biomarkers of oxidative stress (lipid peroxidation, glutathione, and glutathione S-transferase activity), and the possible influence of environmental factors (temperature, pH, and salinity) were assessed in situ for specimens of Ramnogaster arcuata, a native estuarine fish. PAH levels found in the muscular tissue of R. arcuata ranged from 0.7 to 293.4 ng g−1 wet weight with petrogenic and pyrolytic inputs. Lipid peroxidation in the liver showed positive correlations (P < 0.05) with total PAHs (r = 0.66), 3-ring (r = 0.66) and 4-ring PAHs (r = 0.52) and glutathione in muscle (r = 0.58). Significant positive correlations (P < 0.05) were also evidenced between muscular glutathione with total (r = 0.62) and 3-ring PAHs (r = 0.75). Hepatic glutathione S-transferase negatively correlated with 4-ring PAHs (r = −0.58). These correlations suggest that lipid peroxidation and muscular glutathione could be good biomarkers for complex mixtures of PAHs, and hepatic glutathione S-transferase could be a suitable biomarker for 4-ring PAHs. Furthermore, significant correlations (P < 0.05) of environmental factors with PAH levels and biomarkers were observed, especially pH with 3-ring PAHs (r = −0.65), lipid peroxidation (r = −0.6), glutathione in the liver (r = −0.73) and muscle (r = −0.75); and temperature with 2-ring PAHs (r = −0.75) and glutathione in muscle (r = 0.51). The data suggest an influence of physicochemical parameters which could be driving a shift in PAH toxicity in R. arcuata. These results are essential for an integrated understanding of ecotoxicology and could help to predict environmental effects in present and future scenarios of ocean warming and acidification.

PAH bioremediation with Rhodococcus rhodochrous ATCC 21198: Impact of cell immobilization and surfactant use on PAH treatment and post-remediation toxicity

Polycyclic aromatic hydrocarbons (PAHs) are prevalent environmental contaminants that are harmful to ecological and human health. Bioremediation is a promising technique for remediating PAHs in the environment, however bioremediation often results in the accumulation of toxic PAH metabolites. The objectives of this research were to demonstrate the cometabolic treatment of a mixture of PAHs by a pure bacterial culture, Rhodococcus rhodochrous ATCC 21198, and investigate PAH metabolites and toxicity. Additionally, the surfactant Tween ® 80 and cell immobilization techniques were used to enhance bioremediation. Total PAH removal ranged from 70–95% for fluorene, 44–89% for phenanthrene, 86–97% for anthracene, and 6.5–78% for pyrene. Maximum removal was achieved with immobilized cells in the presence of Tween ® 80. Investigation of PAH metabolites produced by 21198 revealed a complex mixture of hydroxylated compounds, quinones, and ring-fission products. Toxicity appeared to increase after bioremediation, manifesting as mortality and developmental effects in embryonic zebrafish. 21198′s ability to rapidly transform PAHs of a variety of molecular structures and sizes suggests that 21198 can be a valuable microorganism for catalyzing PAH remediation. However, implementing further treatment processes to address toxic PAH metabolites should be pursued to help lower post-remediation toxicity in future studies.

Association between polycyclic aromatic hydrocarbons and infertility in U.S. women: National Health and Nutrition Examination Survey 2013–2016

Although there is a body of research indicating the potential impact of polycyclic aromatic hydrocarbons (PAHs) exposure on male infertility, the understanding of how PAH might affect female infertility is still limited. This study aimed to evaluate associations of PAHs, both individually and as a mixture, with female infertility using multiple logistic regression, Bayesian kernel machine regression (BKMR), and quantile g-computation (QGC) models based on data from the National Health and Nutrition Examination Survey (NHANES) 2013–2016. The study included 729 female participants. Multiple logistic regression results indicated that there was a significant association between the third tertile of 2-hydroxy fluorene (2-OHFLU) and female infertility, and the OR was 2.84 (95% CI: 1.24–6.53, P value = 0.015) compared with the first tertile after adjusting for the potential covariates. The BKMR model revealed a positive overall trend between mixed PAH exposure and female infertility, particularly when the mixture was at or above the 55th percentile, where 2-hydroxynaphthalene (2-OHNAP) and 1-hydroxypyrene (1-OHPYR) were the primary influences of the mixture. The univariate exposure-response function indicated positive associations between individual PAH exposure, specifically 2-OHNAP, 2-OHFLU, and 1-OHPYR, and female infertility. The QGC model also indicated a positive trend between exposure to a mixture of PAHs and female infertility, although it did not reach statistical significance (OR = 1.33, 95%CI: 0.86–2.07), with 1-OHPYR having the greatest positive effect on the outcome. This study suggested that exposure to PAHs may be associated with female infertility and further research is needed to consolidate and confirm these findings.

Design and evaluation of semicarbazide-embeddedd stationary phases for liquid chromatography

Semicarbazide, as a derivative of urea, constitutes a great variety of functional molecules for different needs. Herein, novel stationary phases with an incorporated semicarbazide group were proposed. Using aliphatic (docosanoyl, C22) and aromatic (benzoyl, Bz) hydrazides, the semicarbazide-embedded ligands were synthesized before chemical modification of the silica gel, allowing for an accurate interpretation of the chromatographic properties of the corresponding packings. The new stationary phases were water-wettable, due to the presence of highly polar groups. In particular, Bz-semicarbazide (Bz-SCD) stationary phase was sufficiently hydrophilic to run in hydrophilic interaction (HILIC) mode, whilst the C22 (C22-SCD) equivalent, in spite of its reversed-phase nature, was markedly less hydrophobic than the referenced polar-embedded ones. The versatility of C22-SCD was demonstrated with a large selection of analytes, including geometric isomers and standard mixtures of polycyclic aromatic hydrocarbons, sulfonamides, sulfonylurea, substituted ureas, pyridines and carbamates, fat-soluble colorants, antifungal metabolites, angiotensin II receptor blockers and calcium channel blockers.

Metabolomics perspectives into the co-exposure effect of polycyclic aromatic hydrocarbons and metals on renal function: A meet-in-the-middle approach

Studies on the dose effects of kidney impairment and metabolomes in co-exposure to polycyclic aromatic hydrocarbons (PAHs) and metals are limited. We aimed to identify overall associations and metabolic perturbations in 130 participants (53 petrochemical workers and 77 controls) exposed to a PAHs-metals mixture in Southern China. The urinary 7 hydroxylated PAHs and 15 metal(loid)s were determined, and serum creatinine, beta-2 microglobulin, and estimated glomerular filtration rate were health outcomes. The liquid chromatography-mass spectrometry-based method was applied to serum metabolomics. Generalized weighted quantile sum (gWQS) regressions were used to estimate the overall dose-response relationships, and pathway analysis, “meet-in-the-middle” approach, and mediation effect analyses were conducted to identify potential metabolites and biological mechanisms linking exposure with nephrotoxic effects. Our results indicated that renal function reduction was associated with a PAHs-metals mixture in a dose-dependent manner, and 1-hydroxynaphthalene and copper were the most predominant contributors among the two families of pollutants. Furthermore, the metabolic disruptions associated with the early onset of kidney impairment induced by the combination of PAHs and metals encompassed pathways such as phenylalanine-tyrosine-tryptophan biosynthesis, phenylalanine metabolism, and alpha-linolenic acid metabolism. In addition, the specifically identified metabolites demonstrated excellent potential as bridging biomarkers connecting the reduction in renal function with the mixture of PAHs and metals. These findings shed light on understanding the overall associations and metabolic mechanism of nephrotoxic effects of co-exposure to PAHs and metals.

Degradation of a mixture of 13 polycyclic aromatic hydrocarbons by commercial effective microorganisms.

The study focused on the contribution of effective microorganisms (EM) and their consortia, used in commercial biological preparations and formulations for soil revitalization, to the degradation of a mixture of 13 polycyclic aromatic hydrocarbons (PAHs) commonly found in the soil environment. PAHs, diverse forms of which are present in the environment, never occur individually but always as a part of a chemical mixture. Therefore, the research presented in this article, focusing on the EM impact on the mixture of PAHs, reflects the conditions most similar to natural ones. On Day 35 of the experiment, PAH levels decreased by 75.5-95.5%. The highest PAHs degradation efficiency was achieved for fluorene, with a preparation containing eight bacteria strains from the Bacillus genus: B. coagulans, B. amyloliquefaciens, B. laterosporus, B. licheniformis, B. mucilaginosus, B. megaterium, B. polymyxa, and B. pumilus. All tested preparations containing bacterial consortia and a preparation with the yeast S. cerevisiae intensified the PAHs degradation more effectively than formulations including only the yeast Yarrowia lipolytica or a mixture of Debaryomyces hansenii and Bacillus. The designed and proposed research will contribute to the development of biotechnological methods - bioremediation by microorganisms that are safe for the human and environment health.

A new strategy of using periphyton to simultaneously promote remediation of PAHs-contaminated soil and production of safer crops

Contaminated farmland leads to serious problems for human health through biomagnification in the soil-crop-human chain. In this paper, we have established a new soil remediation strategy using periphyton for the production of safer rice. Four representative polycyclic aromatic hydrocarbons (PAHs), including phenanthrene (Phe), pyrene (Pyr), benzo[b]fluoranthene (BbF), and benzo[a]pyrene (BaP), were chosen to generate artificially contaminated soil. Pot experiments demonstrated that in comparison with rice cultivation in polluted soil with ΣPAHs (50 mg kg−1) but without periphyton, adding periphyton decreased ΣPAHs contents in both rice roots and shoots by 98.98% and 99.76%, respectively, and soil ΣPAHs removal reached 94.19%. Subsequently, risk assessment of ΣPAHs based on toxic equivalent concentration (TEQ), pollution load index (PLI), hazard index (HI), toxic unit for PAHs mixture (TUm), and incremental lifetime cancer risk (ILCR) indicated that periphyton lowered the ecological and carcinogenicity risks of PAHs. Besides, the role of periphyton in enhancing the rice productivity was revealed. The results indicated that periphyton alleviated the oxidative stress of PAHs on rice by reducing malondialdehyde (MDA) content and increasing total antioxidant capacity (T-AOC). Periphyton reduced the toxic stress of PAHs on the soil by promoting soil carbon cycling and metabolic activities as well. Periphyton also improved the soil's physicochemical properties, such as the percentage of soil aggregate, the contents of humic substances (HSs) and nutrients, which increased rice biomass. These findings confirmed that periphyton could improve rice productivity by enhancing soil quality and health. This study provides a new eco-friendly strategy for soil remediation and simultaneously enables the production of safe crops on contaminated land.

Occurrence, sources and water column distribution trends of suspended particle-associated aliphatic and polycyclic aromatic hydrocarbons in the open northeastern Mediterranean Sea

Herein, we study the occurrence and water column distribution trends of suspended particle-associated aliphatic (AHCs) and polycyclic aromatic hydrocarbons (PAHs) collected from 36 offshore/deep sea locations across the open northeastern Mediterranean Sea. Total concentrations of the determined compounds fall within the range previously reported for non-polluted coastal and open sea locations worldwide. Mixed natural and anthropogenic sources were evident for the studied compounds, based on their molecular profile and several diagnostic indices. In all cases, an enhanced fossil signal typifying chronic oil pollution was evident along the water column. AHCs and PAHs mixtures characteristics varied significantly within the studied sub-regions, highlighting the importance of inputs from various point sources and dispersion pathways. The circulation characteristics of water masses along with biogeochemical features impact on the water column distribution trends and overall fate of the determined compounds in the study area.

Differences in phytoplankton population vulnerability in response to chemical activity of mixtures.

Hydrophobic organic contaminants (HOCs) affect phytoplankton at cellular to population levels, ultimately impacting communities and ecosystems. Baseline toxicants, such as some HOCs, predominantly partition to biological membranes and storage lipids. Predicting their toxic effects on phytoplankton populations therefore requires consideration beyond cell uptake and diffusion. Functional traits like lipid content and profile can offer insights into the diverse responses of phytoplankton populations exposed to HOCs. Our study investigated the vulnerability of five phytoplankton species populations to varying chemical activities of a mixture of polycyclic aromatic hydrocarbons (PAHs). Population vulnerability was assessed based on intrinsic sensitivities (toxicokinetic and toxicodynamic), and demography. Despite similar chemical activities in biota within the exposed algae, effects varied significantly. According to the chemical activity causing 50% of the growth inhibition (Ea50), we found that the diatom Phaeodactylum tricornutum (Ea50 = 0.203) was the least affected by the chemical exposure and was also a species with low lipid content. In contrast, Prymnesium parvum (Ea50 = 0.072) and Rhodomonas salina (Ea50 = 0.08), both with high lipid content and high diversity of fatty acids in non-exposed samples, were more vulnerable to the chemical mixture. Moreover, the species P. parvum, P. tricornutum, and Nannochloris sp., displayed increased lipid production, evidenced as 5-10% increase in lipid fluorescence, after exposure to the chemical mixture. This lipid increase has the potential to alter the intrinsic sensitivity of the populations because storage lipids facilitate membrane repair, reconstitution and may, in the short-term, dilute contaminants within cells. Our study integrated principles of thermodynamics through the assessment of membrane saturation (i.e. chemical activity), and a lipid trait-based assessment to elucidate the differences in population vulnerability among phytoplankton species exposed to HOC mixtures.

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) augments neonatal hyperoxic lung injury: Role of cytochrome P450 (CYP)1A1, 1A2, and 1B1

Pregnant women exposed to polycyclic aromatic hydrocarbons (PAHs) are at increased risk for premature delivery. Premature infants often require supplemental oxygen, a known risk factor for bronchopulmonary dysplasia (BPD). Cytochrome P450 (CYP) enzymes have been implicated in hyperoxic lung injury. We hypothesize that prenatal PAH exposure exacerbates oxygen-mediated lung injury in neonatal mice, and that this effect is differentially altered in mice lacking the gene for (Cyp)1a1, 1a2, or 1b1. Timed pregnant wild type (WT) (C57BL/6J) mice were orally administered a PAH mixture of benzo[a]pyrene (BP) and benzo[b]fluoranthene (BbF) or the vehicle corn oil (CO) once daily on gestational days 16–19, and the dose response on postnatal lung injury was examined. In addition, timed pregnant mice with one of four genotypes, WT, Cyp1a1-null, Cyp1a2-null, and Cyp1b1-null, were treated orally with CO or PAH on gestational days 16–19 and exposed to hyperoxia or room air for 14 days. Lung injury was assessed on PND15 by radial alveolar count (RAC) and mean linear intercept (MLI) Gene expression of DNA repair genes in lung and liver were measured. Results showed that neonatal hyperoxic lung injury is augmented by prenatal PAH exposure in a dose-dependent manner. This effect was differentially altered in the Cyp-null mice, with Cyp1a2-null showing the greatest extent of lung injury. We concluded that newborn mice exposed to PAH in utero had more significant lung injury in response to hyperoxia than non-PAH exposed pups, and that CYP1A1 and CYP1A2 are protective against lung injury while CYP1B1 augments lung injury.

Degradation of a Model Mixture of PAHs by Bacterial-Fungal Co-Cultures.

Bacteria and fungi are the most important soil organisms owing to their abundance and the key roles they play in the functioning of ecosystems. We examined possible synergistic and antagonistic effects during the degradation of polycyclic aromatic hydrocarbons (PAHs) by co-cultures of ascomycetes and a plant-growth-promoting bacterium. Bacteria and fungi were grown in a liquid nutrient medium supplemented with PAHs. The PAH degradations and the identification of metabolites were checked by high-performance liquid chromatography (HPLC). Enzymatic activities were measured spectrophotometrically using test substrates. All experimental treatments were analyzed using Excel 2019 (Microsoft Office 2019, USA). The model system included the plant-growth-promoting rhizobacterium (PGPR) Azospirillum brasilense and one of the following ascomycetes: Fusarium oxysporum (plant pathogen), Talaromyces sayulitensis (rhizospheric fungus), Trichoderma viride (plant-growth-promoting fungus, PGPF), and Trichoderma harzianum (PGPF). The notable results are: (1) synergistic effects consisted of more active utilization of the PAH mixture compared to individual compounds, while the PAH mixture was more actively degraded by co-cultures than monocultures; (2) three effects of mutual influence by the studied organisms were also revealed: depressing (F. oxysporum and A. brasilense), partially depressing (T. sayulitensis suppressed the growth of A. brasilense but increased the degradation of anthracene, pyrene, and fluoranthene), and positive effects (A. brasilense and T. viride or T. harzianum); (3) for the first time quinone metabolites of PAH degradation and extracellular oxidase and peroxidase were produced during PAH degradation by T. sayulitensis.Conclusions: The results of the study contribute to the understanding of bacterial-fungal interactions in polluted settings.

Evidence of transboundary movement of chemicals from Mexico to the U.S. in Tijuana River Estuary sediments

The Tijuana River Estuary (TRE) has been a public health hazard and point of contention between the United States and Mexico for decades, with sources of pollution on both sides of the border. The goal of our study is to determine the presence and dynamics of chemical contamination in the TRE. We sampled sediment from four TRE locations in the U.S. during stable dry conditions and immediately after a wet weather period. Organic chemicals were initially screened with non-targeted analysis using gas chromatography high-resolution mass spectrometry (GC/HRMS) that tentatively identified 6978 chemicals in the NIST 20 database. These tentative identifications were filtered using the USEPA CompTox database to guide quantitative targeted analysis at detection limits below 1 ng/g dry weight sediment. Quantitative targeted analysis of 152 organic pollutants and 18 inorganic elements via GC/HRMS revealed generally higher concentrations of contaminants in dry weather sediments compared to wet weather sediments. The highest concentrations of all chemical classes were detected at the site closest to the U.S.-Mexico border, followed by an urban area near Imperial Beach, California, U.S. All sites exhibited a mixture of petrogenic and pyrogenic polycyclic aromatic hydrocarbons (PAHs). Current-use pesticides were dominated by pyrethroid insecticides and the thiocarbamate herbicide s-Ethyl dipropylthiocarbamate (EPTC), while the U.S.-banned organochlorine pesticides were dominated by chlordanes, dieldrin, and dichlorodiphenyltrichloroethane (DDT) and its degradation byproducts. Polychlorinated biphenyl (PCB) concentrations were greatest at the site closest to the U.S.-Mexico border but in the low nanogram-per-gram range. Phthalates were only found at the same site, with relatively high concentrations of bis(2-ethylhexyl) phthalate. This study provides positive identification and quantitative concentrations for organic pollutants in TRE sediments. Our data suggest that there are multiple sources of chemical contamination in the estuary, including possible transboundary movement of pollutants from Mexico.

Remediation of persistent organic pollutants through statistical treatment using the CoFe2O4@Fe3O4-based magnetic nanocomposite

In the present study, the CoFe2O4@Fe3O4-based magnetic nanocomposite was synthesized and applied as an adsorbent material in the polycyclic aromatic hydrocarbons (PAHs) remediation, which include phenanthrene (Phe), benzo[b]fluoranthene (B[b]F), benzo[k]fluoranthene (B[k]F), and benzo[a]pyrene (B[a]P). The experimental conditions were investigated using a factorial experimental design (24) with the aim of carrying out a systematic evaluation of the solution pH, equilibrium time, concentration of pollutants, and magnetic nanocomposite mass. The characterization of the CoFe2O4@Fe3O4 adsorbent by the FTIR and XRD analyses showed success in the formation of magnetic nanoparticles. In addition, the SEM–EDS analysis exhibited images of nanometric spheres, uniform morphology, and the presence of Fe, Co and O as main components, as well as a type IV isotherms with H1 hysteresis as a typical formation of a mesoporous nanocomposite with high surface area (244.28 m2 g−1) and large pore volume (0.19 cm3 g−1). The statistical treatment revealed that the pH and the adsorption time are variables that little or nothing influenced the adsorptive properties of the CoFe2O4@Fe3O4 to remove the PAHs mixture, contrary to the PAHs concentration and the CoFe2O4@Fe3O4 mass, which are important variables. Finally, the best experimental conditions were obtained for the adsorption tests between 13 (pH 3, time = 5 min, concentration = 1000 µg L−1, and mass = 50 mg) and 16 (pH 10, time = 200 min, concentration = 1000 µg L−1, and mass = 50 mg), whose overall desirability (OD) values were 1.00 and removal efficiency varied between 92.40 and 96.60 %; 95.00–97.00 %; 90.80–96.30 %; and 93.50–96.80 %, respectively, for Phe, B[b]F, B[k]F, and B[a]P.

Dual effect of polyaromatic hydrocarbons on sarco(endo)plasmic reticulum calcium ATPase (SERCA) activity of a teleost fish (Oncorhynchus mykiss)

Polycyclic aromatic hydrocarbons (PAHs) are embryo- and cardiotoxic to fish that might be associated with improper intracellular Ca2+ management. Since sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a major regulator of intracellular Ca2+, the SERCA activity and the contractile properties of rainbow trout (Oncorhynchus mykiss) ventricle were measured in the presence of 3- and 4-cyclic PAHs. In unfractionated ventricular homogenates, acute exposure of SERCA to 0.1–1.0 μM phenanthrene (Phe), retene (Ret), fluoranthene (Flu), or pyrene (Pyr) resulted in concentration-dependent increase in SERCA activity, except for the Flu exposure, with maximal effects of 49.7–83 % at 1 μM. However, PAH mixture did not affect the contractile parameters of trout ventricular strips. Similarly, all PAHs, except Ret, increased the myotomal SERCA activity, but with lower effect (27.8–40.8 % at 1 μM). To investigate the putative chronic effects of PAHs on SERCA, the atp2a2a gene encoding trout cardiac SERCA was expressed in human embryonic kidney (HEK) cells. Culture of HEK cells in the presence of 0.3–1.0 μM Phe, Ret, Flu, and Pyr for 4 days suppressed SERCA expression in a concentration-dependent manner, with maximal inhibition of 49 %, 65 %, 39 % (P < 0.05), and 18 % (P > 0.05), respectively at 1 μM. Current findings indicate divergent effects of submicromolar PAH concentrations on SERCA: stimulation of SERCA activity in acute exposure and inhibition of SERCA expression in chronic exposure. The depressed expression of SERCA is likely to contribute to the embryo- and cardiotoxicity of PAHs by depressing muscle function and altering gene expression.

Using machine learning methods to analyze the association between urinary polycyclic aromatic hydrocarbons and chronic bowel disorders in American adults

The etiology of chronic bowel disorders is multifaceted, with environmental exposure to harmful substances potentially playing a significant role in their pathogenesis. However, research on the correlation between polycyclic aromatic hydrocarbons (PAHs) and chronic bowel disorders remains limited. Using data from the National Health and Nutrition Examination Survey (NHANES) conducted in 2009–2010, we investigated the relationship between 9 PAHs and chronic diarrhea and constipation in U.S. adults. We employed unsupervised methods such as clustering and Principal Component Analysis (PCA) to identify participants with similar exposure patterns. Additionally, we used supervised learning techniques, namely weighted quantile sum (WQS) and Bayesian kernel machine (BKMR) regressions, to assess the association between PAHs and the occurrence of chronic diarrhea and chronic constipation. PCA identified three principal components in the unsupervised analysis, explaining 86.5% of the total PAH variability. The first component displayed a mild association with chronic diarrhea, but no correlation with chronic constipation. Participants were divided into three clusters via K-means clustering, based on PAH concentrations. Clusters with higher PAH exposure demonstrated an increased odds ratio for chronic diarrhea, but no meaningful connection with chronic constipation. In the supervised analysis, the WQS regression underscored a positive relationship between the PAH mixture and chronic diarrhea, with three PAHs significantly impacting the mixture effect. The mixture index showed no correlation with chronic constipation. BKMR analysis illustrated a positive trend in the impact of four specific PAHs on chronic diarrhea, given other metabolites were fixed at their 50th percentiles. Our results suggest a clear association between higher PAH exposure and an increased risk of chronic diarrhea, but not chronic constipation. It also underscores the potential role of specific PAHs in contributing to the risk of chronic diarrhea.

Single and Joint Associations of Polycyclic Aromatic Hydrocarbon Exposure with Liver Function during Early Pregnancy.

The individual and combined associations of polycyclic aromatic hydrocarbons (PAHs) metabolites on liver function during pregnancy are still lacking. We aimed to explore the connection between urinary PAH metabolites and liver function in early pregnant women in southwest China based on the Zunyi birth cohort. Ten urinary PAH metabolites and five liver function parameters during early pregnancy were measured. The associations of single PAHs with parameters of liver function were assessed using multiple linear regression. A Bayesian kernel machine regression (BKMR) model was used to evaluate the joint associations of the PAH mixture with outcomes. We found that each 1% increment of urinary 2-hydroxyphenanthrene (2-OH-PHE) was associated with 3.36% (95% CI: 0.40%, 6.40%) higher alanine aminotransferase (ALT) and 2.22% (95% CI: 0.80%, 3.67%) higher aspartate aminotransferase (AST). Each 1% increment in 1-hydroxy-phenanthrene (1-OH-PHE) was significantly associated with 7.04% (95% CI: 1.61%, 12.75%) increased total bile acid (TBA). Additionally, there was a significant positive linear trend between 2-OH-PHE and AST and 1-OH-PHE and TBA. BKMR also showed a significant positive association of PAH mixture with AST. Our results indicate that PAH metabolites were associated with increased parameters of liver function among early pregnant women. Early pregnant women should pay more attention to the adverse relationships between PAHs and liver function parameters to prevent environment-related adverse perinatal outcomes.

Modulation of the Cardiovascular Effects of Polycyclic Aromatic Hydrocarbons: Physical Exercise as a Protective Strategy.

Exposure to polycyclic aromatic hydrocarbons (PAHs) present in air pollution increases cardiovascular risk. On the contrary, physical exercise is a widely used therapeutic approach to mitigate cardiovascular risk, but its efficacy in an environment of air pollution, particularly with PAHs, remains unclear. This study investigates the effects of exercise on inflammation, endothelial dysfunction, and REDOX imbalance due to PAH exposure using a mouse model. Twenty male BALB/c mice were subjected to a mixture of PAHs (phenanthrene, fluoranthene, pyrene) in conjunction with aerobic exercise. The investigation evaluated serum levels of inflammatory cytokines, gene expression linked to inflammatory markers, endothelial dysfunction, and REDOX imbalance in aortic tissues. Furthermore, the study evaluated the expression of the ICAM-1 and VCAM-1 proteins. Exercise led to notable changes in serum inflammatory cytokines, as well as the modulation of genes associated with endothelial dysfunction and REDOX imbalance in aortic tissue. In turn, exercise produced a modulation in the protein expression of ICAM-1 and VCAM-1. The findings implicate the potential of exercise to counter PAH-induced damage, as demonstrated by changes in markers. In conclusion, exercise could mitigate the adverse effects related to exposure to PAHs present in air pollution, as evidenced by changes in inflammatory markers, endothelial dysfunction, and REDOX imbalance.

Gender-specific associations between mixture of polycyclic aromatic hydrocarbons and telomere length.

Evidence shows the relationships of individual environmental PAHs by their urinary metabolites with relative telomere length (RTL), which may be affected by biological gender differences. Since plasma parent PAHs are not metabolized, it may reflect human exposure to PAHs more realistically in daily life. Thus, exploring joint associations between plasma parent PAHs and RTL is urgent, which may identify the major contributor to its adverse effect. In this study,2577 participants were obtained from the Henan Rural Cohort. The level of PAHs in blood samples was detected by gas chromatography coupled with tandem mass spectrometry. RTL in blood samples was detected by quantitative polymerase chain reaction. Generalized linear models or quantile g-computation were performed to evaluate the associations between the individual or a mixture of PAHs and RTL. Results from generalized linear models showed that each unit increment in BghiP value corresponded to a 0.098 (95%CI: 0.067, 0.129) increment in RTL for men; each unit increment in BaP, BghiP and Flu value corresponded to a 0.041 (95%CI: 0.014, 0.068), 0.081 (95%CI: 0.055, 0.107) and 0.016 (95%CI: 0.005, 0.027) increment in RTL for women. Results from quantile-g computation revealed that each one-quantile increment in the mixture of 10 PAHs corresponded to a 0.057 (95%CI: 0.021, 0.094) and 0.047 (95%CI: 0.003, 0.091) increment in RTL valuesof women and men, but these associations were mainly ascribed to three PAHs for women (BaP, Flu and BghiP) and men (BaP, BghiP and Pyr), respectively. Similar results were found in smoking men and cooking women without smoking. Our study foundthat exposure to 10 PAHs mixture was positively associated with RTL across gender, mainly attributed to Flu, BaP and BghiP, implicating that gender-specific associations may be ascribed to tobacco and cooking smoke pollution. The findings provided clues for effective measures to control PAHs pollutants-related aging disease.Clinical trial registration The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 .