Bioaccessibility and health risk assessment of hydrophobic organic pollutants in soils from four typical industrial contaminated sites in China.

There have been reports of potential health risks for people from hydrophobic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated hydrocarbons (PCHs), and organophosphate flame retardants (OPFRs). When a contaminated site is used for residential housing or public utility and recreation areas, the soil-bound organic pollutants might pose a threat to human health. In this study, we investigated the contamination profiles and potential risks to human health of 15 PAHs, 6 PCHs, and 12 OPFRs in soils from four contaminated sites in China. We used an in vitro method to determine the oral bioaccessibility of soil pollutants. Total PAHs were found at concentrations ranging from 26.4 ng/g to 987 ng/g. PCHs (0.27‒14.3 ng/g) and OPFRs (6.30‒310 ng/g) were detected, but at low levels compared to earlier reports. The levels of PAHs, PCHs, and OPFRs released from contaminated soils into simulated gastrointestinal fluids ranged from 1.74% to 91.0%, 2.51% to 39.6%, and 1.37% to 96.9%, respectively. Based on both spiked and unspiked samples, we found that the oral bioaccessibility of pollutants was correlated with their logKow and molecular weight, and the total organic carbon content and pH of soils. PAHs in 13 out of 38 contaminated soil samples posed potential high risks to children. When considering oral bioaccessibility, nine soils still posed potential risks, while the risks in the remaining soils became negligible. The contribution of this paper is that it corrects the health risk of soil-bound organic pollutants by detecting bioaccessibility in actual soils from different contaminated sites.

Associations of polycyclic aromatic hydrocarbons exposure with serum uric acid and hyperuricemia in US adults: The role of systemic inflammation.

The associations of polycyclic aromatic hydrocarbon (PAH) exposure with serum uric acid (SUA) or hyperuricemia have been rarely assessed. We aimed to investigate the relationships between urinary PAH metabolites and SUA or hyperuricemia among US adults and to explore the mediating role of systemic inflammation in the associations. A total of 10,307 US adults were conducted to assess the associations of seven urinary hydroxy­PAH with SUA and hyperuricemia and evaluate the role of C-reactive protein (CRP), a biomarker of systemic inflammation, in such associations. Results showed that each 1-unit increase in ln-transformed 2-hydroxynaphthalene (2-OHNa), 1-hydroxyphenanthrene (1-OHPh), 2&3-hydroxyphenanthrene (2&3-OHPh) and total hydroxyphenanthrene (ΣOHPh) was associated with a 1.68 (95% confidence interval (CI): 0.19 to 3.17), 2.46 (0.78 to 4.13), 3.34 (1.59 to 5.09), and 2.99 (1.23 to 4.75) µmol/L increase in SUA, and a 8% (odds ratio (OR): 1.08, 1.02 to 1.15), 9% (OR: 1.09, 1.02 to 1.18), 13% (OR: 1.13, 1.05 to 1.22), and 12% (OR: 1.12, 95% CI: 1.03, 1.21) increase in hyperuricemia, respectively. Co-exposure of seven PAHs was positively associated with SUA and hyperuricemia, with 2&3-OHPh showing the highest weight (components weights: 0.83 and 0.78, respectively). The CRP mediated 11.47% and 10.44% of the associations of ΣOHPh and 2&3-OHPh with SUA and mediated 8.60% and 8.62% in associations of ΣOHPh and 2&3-OHPh with hyperuricemia, respectively. In conclusion, internal levels of PAH metabolites were associated with elevated SUA levels and the increased risk of hyperuricemia among US adults, and CRP played a mediating role in the associations.

Effects of single and combined urinary polycyclic aromatic hydrocarbon effects on lung function in the U.S. adult population.

BACKGROUND: The impact of polycyclic aromatic hydrocarbons (PAHs) on lung function has garnered attention, but studies mostly focus on individual effect. This study investigates urinary PAH metabolites as biomarkers of exposure and assesses the relationships between single and combined exposures to nine urinary PAH metabolites and lung function in adults. METHODS: Data from 4040 adults in the 2007-2012 National Health and Nutrition Examination Survey (NHANES) were analyzed. Weighted generalized linear models estimated the effects of individual PAH metabolites on lung function. Additionally, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) were employed to evaluate the combined impacts of multiple PAH metabolites. RESULTS: Analyses of individual PAH metabolites revealed negative associations with lung function, excluding forced vital capacity (FVC). The WQS, qgcomp, and BKMR models consistently showed that exposure to multiple PAH metabolites was associated with lung function decrease. WQS indicated that 2-hydroxynaphthalene (2-NAP) was the largest contributor to the reductions in forced expiratory volume in 1 s (FEV1), FVC, peak expiratory flow (PEF), and forced expiratory flow from 25 to 75% of FVC (PEF25-75%). Additionally, 1-hydroxypyrene (1-PYR) was the primary PAH metabolite contributing to the decreases in FEV1/FVC and fractional exhaled nitric oxide (FeNO). The combined effect of urinary PAH metabolites did not affect FVC in the current smokers or FeNO in nonsmokers, but decreased FEV1/FVC in current smokers. CONCLUSION: This study strengthens the negative relationships between multiple PAH metabolites exposure and lung function in adults. Given the limitations of this study, including the lack of knowledge of other exposure pathways and the uncertainty of urinary metabolites, further research is necessary to explore the mechanisms underlying these associations and to address the limitations in exposure assessment.

Anti-Neuroinflammatory Potential of Areca Nut Extract and Its Bioactive Compounds in Anthracene-Induced BV-2 Microglial Cell Activation.

Particulate matter (PM2.5) containing polycyclic aromatic hydrocarbons (PAHs) is of considerable environmental importance worldwide due to its adverse effects on human health, which are associated with neurodegenerative diseases (NDDs). Areca catechu L. (AC) fruit is known to possess various pharmacological properties; however, the anti-neuroinflammatory roles of AC on the suppression of PAH-induced neuroinflammation are still limited. Thus, we focused on the effects and related signaling cascades of AC and its active compounds against anthracene-induced toxicity and inflammation in mouse microglial BV-2 cells. Phytochemicals in the ethanolic extract of AC (ACEE) were identified using LC-MS, and molecular docking was conducted to screen the interaction between compounds and target proteins. Significant bioactive compounds in ACEE such as arecoline, (-)-epicatechin, and syringic acid were evinced through the LC-MS spectrum. The docking study revealed that (-)-epicatechin showed the highest binding affinities against NF-κB. For cell-based approaches, anthracene induced intracellular ROS, mRNA levels of TNF-α, IL-1ß, and IL-6, and the release of TNF-α through enhancing JNK, p38, and NF-κB signaling pathways. However, the co-treatment of cells with ACEE or (-)-epicatechin could reverse those anthracene-induced changes. The overall study suggested that ACEE-derived bioactive compounds such as (-)-epicatechin may be developed as a potential anti-neuroinflammatory agent by preventing inflammation-mediated NDDs.

Enzymatic bioremediation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil: a study on the recombinant laccase TVL.

Polycyclic aromatic hydrocarbons (PAHs) are pervasive and persistent pollutants in contaminated soil, posing a severe health and environmental threat. Enzymatic bioremediation presents a viable solution for the remediation of PAH-contaminated soil. In this study, a recombinant laccase with the encoding gene originating from Trametes villosa and recombinantly expressed in Aspergillus oryzae, designated as TVL, was discovered to possess strong PAH reduction capabilities. The specific enzyme activity of TVL was 73485 and 5102 LAMU/g enzyme protein at pH 5.0/7.0 and 37°C. Furthermore, it exhibited significant benzo[a]pyrene degradation, with 100% and 90.48% degradation at pH 5.0/7.0 after 24 h in the liquid phase. The degradation process of benzo[a]pyrene in soil was thoroughly investigated. Optimal conditions were identified as 15 mg/g NK-BSoil-3 and 1.35 mg/g HBT, resulting in a removal rate of 37.54% within 7 days when 0.01 U/g of TVL was applied. The potential mechanisms were investigated using molecular docking simulation. The binding energy between benzo[a]pyrene and TVL protein is notably robust, suggesting a higher propensity for enzyme binding. The TVL protein pocket contains nine amino acids that can interact most strongly with benzo[a]pyrene. Consequently, the recombinant laccase TVL holds considerable practical significance in bioremediation.

Unintentionally-produced persistent organic pollutants in the aquatic environment contaminated from historical chlor-alkali production.

Historical chlor-alkali production has led to substantial concentrations of persistent organic pollutant residues in the environment. This study systematically investigated the distribution of polycyclic aromatic hydrocarbons (PAHs), chlorinated/brominated-PAHs (Cl/Br-PAHs), polychlorinated naphthalenes (PCNs), and hexachlorobutadiene (HCBD) in sediment, lotus (Nelumbo nucifera), and fish samples from Ya-Er Lake, which is a site in China with historical chlor-alkali contamination. The average concentrations [(4.97-1.47) × 103 ng/g dry weight (dw)] of these pollutants in backfill sediments, which were dredged from the lake after chlor-alkali production stopped, were 2.68-70.87 times those in fresh lake sediments (0.622-218 ng/g dw) and reported concentrations in other areas. Correlation analyses indicated that Cl-PAHs, Br-PAHs, and PCNs likely originated from halogenation of parent PAHs in the study area, and the chlorination ratios were larger than those of bromination. The Cl(1/2/3)-PAHs/PAHs and Br(1)-PAHs/PAHs ratios were higher than those for PAHs with more halogen atoms. This contamination extended into the biota, with notable pollutant burdens found in lotus (Nelumbo nucifera, 0.305-77.3 ng/g dw) and even higher concentrations in fish (2.20-345 ng/g lipid weight). Estimated biological soil accumulation factors revealed significant enrichment in lotus organs (mean: 7.19) and fish muscle (mean: 10.65), especially the latter, which highlighted bioaccumulation and potential food chain transfer risks. The estimated daily intakes of PAHs, Cl/Br-PAHs, and HCBD through fish consumption currently pose negligible risks, while dietary intake of PCNs may present health concerns. Continuous monitoring and impact assessments are crucial for developing appropriate risk management strategies to safeguard public health.

Polycyclic aromatic hydrocarbon derivatives onto polar microplastics of polyurethane: equilibrium, thermodynamics, and kinetics of monolayer-multilayer adsorption.

The study of the adsorption of polycyclic aromatic hydrocarbons on microplastics (MPs) has attracted much attention as to how microplastics can act as carriers of these pollutants. Polyurethane (PU) is one of the MPs found in aquatic environments, containing different functional groups it can interact with polar and nonpolar molecules. PAH derivatives (dPAHs) present different properties and thus can be adsorbed by different interactions; thus, this study investigated the adsorption of fluorene (FLN), dibenzothiophene (DBT), dibenzofuran (DBF), and carbazole (CBZ) onto PU MP. The Langmuir, Freundlich, and BET isotherm models were examined, and the BET model best fitted. The adsorption was a nonspontaneous process, exothermic for mono- and multilayer formation for FLN, DBT, and CBZ, and endothermic for DBF monolayer formation. The adsorption monolayer was formed by van der Waals forces, H─bonding, and π─π interactions, while the formation of the multilayer can be explained by π─π and hydrophobic interactions. The pseudo-second-order model proved to be more consistent for the adsorption of dPAHs. The adsorption in artificial seawater shows no significant differences for the monolayer but favored the adsorption multilayer due to the salting-out effect. Due to the existence of several adsorption mechanisms, PU MP interacts with dPAHs in greater quantities when compared to a MP with a simpler structure.

Characterization of a Soft Ionization by Chemical Reaction in Transfer Ion Source Hyphenated With Supercritical Fluid Chromatography-Tandem Mass Spectrometry.

A commercially available dielectric barrier discharge ionization (DBDI) source was tested with supercritical fluid chromatography-mass spectrometry (SFC-MS). The compound mixture investigated comprised caffeine, theobromine, theophylline, uracil, testosterone, and pyrene, diluted in methanol. Dynamic response ranges were evaluated with multiple injections at different concentrations. Precision studies demonstrated the robustness and sensitivity of the ionization source across a concentration range of 10-1000 ng/mL. Results from this experiment showed linear regression of 0.99 or greater for all analytes tested over the range with a relative standard deviation (RSD) of less than 10% down to 10 ng/mL for all analytes except theobromine, which had an RSD of less than 10% down to 25 ng/mL. Notably, this study marks the first investigation of sensitivity for coupling a commercial DBDI source with SFC; a limit of detection less than 1 ng/mL was achieved for all compounds. This study demonstrates chromatographic separation by SFC and MS analysis for compounds that ionize poorly using traditional atmospheric pressure ionization, such as polycyclic aromatic hydrocarbons. Combining SFC with the DBDI source opens promising avenues for analyzing compounds that were previously challenging to characterize with standard atmospheric pressure ionization techniques.

Photo-transformation of biochar-derived dissolved organic matter and its binding with phenanthrene/9-phenanthrol: The role of functional group and pyrolysis temperature.

This study explores the physicochemical attributes of dissolved organic matter from rice straw biochar (BDOM) at varying pyrolysis temperatures and photo-irradiation conditions, focusing on the binding mechanisms of phenanthrene (PHE) and 9-phenanthrol (PTR) using multiple spectroscopic techniques and fluorescence quenching. Following 20 h of photo-irradiation, only 11.3 % of BDOM underwent mineralization, forming new CH3/CH2/CH aliphatics structures. BDOM from biochar produced by pyrolysis at 400°C exhibited a stronger binding affinity with PHE and PTR, achieving 44 % and 52 % maximum binding, respectively. Static and dynamic quenching governed PHE and PTR binding, which was influenced by temperature. Photo-irradiated BDOM showed enhanced binding with PHE, attributed to increased aliphatic content. Hydrogen bond and π-π electron-donor-acceptor (EDA) interactions dominated PTR binding, while π-π interactions and hydrophobic interactions controlled PHE. This study provides valuable insights into BDOM photochemical behaviors and their impact on the environmental fate of polycyclic aromatic hydrocarbons (PAHs) after BDOM photo-irradiation.

An evaluation of in utero polycyclic aromatic hydrocarbon exposure on the neonatal meconium microbiome.

INTRODUCTION: In utero exposure to environmental polycyclic aromatic hydrocarbon (PAH) is associated with neurodevelopmental impairments[1-8], prematurity[9-12] and low birthweight[9,13-15]. The gut microbiome serves as an intermediary between self and external environment; therefore, exploring the impact of PAH on microbiota may elucidate their role in disease. Here, we evaluated the effect of in utero PAH exposure on meconium microbiome. METHODS: We evaluated 49 mother-child dyads within Fair Start Birth Cohort with full term delivery and adequate meconium sampling. Prenatal PAH was measured using personal active samplers worn for 48 h during third trimester. Post-processing, 35 samples with adequate biomass were evaluated for association between tertile of PAH exposure (high (H) vs low/medium (L/M)) and microbiome diversity. RESULTS: No significant differences were observed in alpha diversity metrics, Chao1 and Shannon index, between exposure groups for total PAH. However, alpha diversity metrics were negatively associated with log benzo[a]anthracene (BaA) and log chrysene (Chry) with high exposure, but positively associated with log benzo[a]pyrene (BaP) with low/medium exposure. After adjustment for birthweight and sex, alpha diversity metrics were negatively associated with log BaA, BaP, Chry, Indeno (Zhang et al., 2021; Perera et al., 2018)pyrene (IcdP) and total PAH with high exposure. Conversely, with low/medium exposure, alpha diversity metrics positively correlated with log BaP and benzo[b]fluoranthane (BbF). No significant difference in beta diversity was observed across groups using UniFrac, weighted UniFrac, or Bray-Curtis methods. Differential expression analysis showed differentially abundant taxa between exposure groups. CONCLUSION: Bacterial taxa were detectable in 35/49 (71%) meconium samples. Altered alpha diversity metrics and differentially abundant taxa between groups suggest in utero PAH exposure may impede early colonization. Sample size is limited, but these findings provide supporting evidence for wider scale research. Research on long-term impact of prenatal PAH exposure on childhood health outcomes is ongoing. Differential effects of specific PAHs need further evaluation.

Toxicity of the oil spilled on the Brazilian coast at different degrees of natural weathering to early life stages of the zebrafish Danio rerio.

Toxicity of water accommodated fractions (WAF) from the oil spilled on the Brazilian coast at different stages of weathering were investigated using Danio rerio. Weathering stages included emulsified oil that reached the coast (OM) and oil collected 50 days later deposited on beach sand (OS) or adhered to shore rocks (OR). Parent and alkylated naphthalenes decreased whereas phenanthrenes increased from less weathered WAF-OM to more weathered WAF-OS and WAF-OR. More weathered WAF-OS and WAF-OR were more potent inducers of zebrafish developmental delay, suggesting that parent and alkylated phenanthrenes are involved. However, less weathered WAF-OM was a more potent inducer of failure in swim-bladder inflation than more weathered WAF-OS and WAF-OR, suggesting that parent and alkylated naphthalenes are involved. Decreases in heart rates and increased heart and skeletal deformities were observed in exposed larvae. Lowest observed effect concentrations for different developmental toxicity endpoints are within environmentally relevant polycyclic aromatic hydrocarbon concentrations.

Spatial distribution of polycyclic aromatic hydrocarbons in sediment deposits in a Seine estuary tributary by hyperspectral imaging.

Water bodies allow the storage of sediments from their catchment areas, including sediments containing persistent contaminants. This study used visible and near-infrared hyperspectral imaging to characterize the composition of sediment deposits collected in Martot Pond (France) and to reconstruct the volume of polycyclic aromatic hydrocarbon (PAH) contaminated sediments in the pond. Additionally, combining this method with polychlorinated biphenyl (PCB) analysis enhanced the age model associated with these sediments. To achieve this, indicators of oxides and chlorophyll a (and its derivatives) were employed to correlate various sediment cores, and to propose a sedimentary filling mode for the pond. Furthermore, one sedimentary unit, which appears homogeneous but of variable size within the pond, exhibited repetitive alternations associated with tidal cycles due to a defect in the Martot dam, corresponding to 34 +/- 3 days. A chemometric approach was used to model PAHs with near-infrared hyperspectral imaging data (validation determination coefficient of 0.85, Root Mean Squared Error of Prediction of 1.64 mg/kg). This model was then applied to other cores, coupled with the sedimentary filling mode in the pond, allowing the reconstruction of the volume of PAH contamination. Thus, this study demonstrates that hyperspectral imaging is a powerful tool for estimating various contaminants in sediments: not only is it much faster than conventional chromatographic methods, it also provides a more detailed understanding of a sample, and even of a site through the correlation of multiple core samples.

Evaluation of polycyclic aromatic hydrocarbon contents in marine products in South Korea and risk assessment using the total diet study.

This study investigated levels of eight polycyclic aromatic hydrocarbons (PAH8) compounds in both raw and processed marine products in South Korea. Katsuobushi exhibited the highest concentration of benzo[a]pyrene, at 14.22 µg/kg, exceeding the European Commission's regulation level of 5.0 µg/kg. The total PAH8 concentration in katsuobushi was 220.5 µg/kg. Among the product categories, shellfish had the highest detection rate (70%), followed by fish (19%) and crustacea (8%), with chrysene being the most prominent PAH8 congener in all marine products. Grilled fish predominantly contained pyrogenic PAHs from combustion byproducts, while shellfish primarily contained petrogenic ones from the aquatic environment. Grilling, smoking, and drying processes significantly contributed to the formation of PAH8 in these food products. Based on the results of a risk assessment using a margin of exposure approach through a total diet study, exposure to PAH8 from marine products is considered to pose low concern to the South Korean population. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01491-y.

Enhancing growth and phytoremediation efficiency of Pennisetum purpureum cv. Mahasarakham in weathered PAH-contaminated soil through thidiazuron application.

Polycyclic aromatic hydrocarbons (PAHs) are phytotoxic, which can limit their phytoremediation. When the ability of plants to phytoremediation PAHs is compromised, the application of plant growth regulators can enhance the growth of the plants. This study aimed to determine the best plant growth regulator (1-naphthalene acetic acid, 6-benzyladenine, or thidiazuron) to enhance the phytoremediation ability of sweet grass (Pennisetum purpureum cv. Mahasarakham) when grown in weather PAH-contaminated soil. In a greenhouse study, 0.01 mg/l thidiazuron resulted in the highest growth of sweet grass when compared to the other tested plant growth regulators (dry shoot weight 24.11 ± 1.28 g and dry root weight 0.70 ± 0.02 g). Sweet grass was grown in soil contaminated with PAH, which demonstrated the toxicity to sweet grass by reducing the total chlorophyll (1.01 µg/g fresh weight) and carotenoid (0.28 µg/g fresh weight) contents with proline increased (6.63 µg/g fresh weight). Meanwhile, total chlorophyll, carotenoid, and proline content in leaves of sweet grass grown in non-contaminated soil were 1.68, 0.44, and 5.23 µg/g fresh weight, respectively. When sweet grass was used to phytoremediate PAHs, there were reductions in acenaphthylene (4.69 ± 0.50%), acenaphthene (10.69 ± 1.47%), and phenanthrene (3.61 ± 0.07%), which compared to levels of over 30% in non-planted soil. For the three PAHs, the bioconcentration factors were 1.6 to 2.4, but the translocation factors were below 1, showing limited movement to the aerial parts of the plant, thereby suggesting that the main mechanism is rhizoremediation. Sweet grass is an excellent candidate for PAH remediation, especially when thidiazuron is applied to relieve plant stress.

Thidiazuron at 0.01 mg/l was the best plant growth regulator to stimulate the growth of sweet grass when compared to 1-naphthalene acetic acid and 6-benzyladenine. Sweetgrass enhanced the removal of acenaphthylene, acenaphthene, and phenanthrene from contaminated soil. A possible mechanism for polycyclic aromatic hydrocarbon (PAH) remediation was rhizoremediation, as the accumulation of PAH in sweet grass biomass was limited, and the translocation factor from the root to the shoot was lower than 1. Thidiazuron may indirectly enhance the PAH phytoremediation by sweet grass via increased plant tolerance to PAH toxicity.

Three distinct conductance states in polycyclic aromatic hydrocarbon derivatives.

Tight-binding model (TBM) and density functional theory (DFT) calculations were employed. Both simulations have demonstrated that the electrical conductance for eight polycyclic aromatic hydrocarbons (PAHs) can be modulated by varying the number of aromatic rings (NAR) within the aromatic derivatives. TBM simulations reveal three distinct conductance states: low, medium and high for the studied PAH derivatives. The three distinct conductance states suggested by TBM are supported by DFT transmission curves, where the low conductance evidenced by T(E) = 0, for benzene, naphthalene, pyrene and anthracene. While azulene and anthanthrene exhibit a medium conductance as T(E) = 1, and tetracene and dibenzocoronene possess a high conductance with T(E) = 2. Low, medium and high values were elucidated according to the energy gap E g and E g gaps are strongly dependent on the NAR in the PAH derivatives. This study also suggests that any PAH molecules are a conductor if E g < 0.20 eV. A linear relationship between the conductance and NAR (G ∝ NAR) was found and conductance follows the order G (benzene, 1 NAR) < G (anthanthrene, 4 NAR) < G (dibenzocoronene, 9 NAR). The proposed study suggests a relevant step towards the practical application of molecular electronics and future device application.

Enrichment of Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Strictly Anaerobic Sulfate-Reducing Cultures from Contaminated Soil and Sediment.

Sulfate-reducing bacteria (SRB) are crucial players in global biogeochemical cycling and some have been implicated in the anaerobic biodegradation of organic pollutants, including recalcitrant and hazardous polycyclic aromatic hydrocarbons (PAHs). Obtaining PAH-degrading SRB cultures for laboratories is of paramount importance in the development of the young field of anaerobic biodegradation of PAHs. SRB grow exceptionally slowly on PAH substrates and are highly sensitive to oxygen. Consequently, enrichment and maintenance of PAH-degrading SRB cultures and characterization of the biodegradation process remain a tedious and formidable task, especially for new researchers. To address these technical constraints, we have developed robust and effective protocols for obtaining and characterizing PAH-degrading SRB cultures. In this set of protocols, we describe step-by-step procedures for preparing inocula from contaminated soil or sediment, preparing anoxic medium, establishing enrichment cultures with PAHs as substrates under completely anaerobic sulfate-reducing conditions, successive culture transfers to obtain highly enriched cultures, rapid verification of the viability of SRB in slow-growing cultures, assessment of PAH degradation by extracting residuals using organic solvent and subsequent analysis by gas chromatography-mass spectrometry, and spectrophotometric determination of sulfate and sulfide in miniaturized, medium-throughput format. These protocols are expected to serve as a comprehensive manual for obtaining and characterizing PAH-degrading sulfate-reducing cultures. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Obtaining PAH-degrading strictly anaerobic sulfate-reducing enrichment cultures from contaminated soil and sediment Support Protocol 1: Operation and maintenance of an anaerobic workstation Support Protocol 2: Setup of gas purging systems for preparing anoxic solutions Support Protocol 3: Verification of viability in slow-growing SRB enrichment cultures Support Protocol 4: Extraction of genomic DNA from low-biomass cultures Basic Protocol 2: Extraction of residual PAH from liquid culture and analysis by GC-MS Basic Protocol 3: Spectrophotometric determination of sulfate concentration in SRB cultures Basic Protocol 4: Spectrophotometric determination of sulfide concentrations in SRB cultures by the methylene blue method Alternate Protocol: Spectrophotometric determination of sulfide concentrations in SRB cultures by the colloidal copper sulfide method.

Finer Particle Size Distribution and Potential Higher Toxicity of Elemental Carbon and Polycyclic Aromatic Hydrocarbons Emitted by Ships after Fuel Oil Quality Improvement.

Ship emissions are a significant source of air pollution, and the primary policy to control is fuel oil quality improvement. However, the impact of this policy on particle size distribution and composition characteristics remains unclear. Measurements were conducted on nine different vessels (ocean-going vessels, coastal cargo ships, and inland cargo ships) to determine the impact of fuel upgrading (S < 0.1% m/m marine gas oil (MGO) vs S < 0.5% m/m heavy fuel oil (HFO)) on elemental carbon (EC) and polycyclic aromatic hydrocarbons (PAHs) emitted by ships. (1) Fuel improvement significantly reduced EC and PAH emission, by 31 ± 25 and 45 ± 38%, respectively. However, particle size distributions showed a trend toward finer particles, with the peak size decreasing from DP = 0.38-0.60 µm (HFO) to DP = 0.15-0.25 µm (MGO), and the emission factor of DP < 100 nm increased. (2) Changes in emission characteristics led to an increase in the toxicity of ultrafine particulate matter. (3) Ship types and engine conditions affected the EC and PAH particle size distributions. Inland ships have a more concentrated particle size distribution. Higher loads result in higher emissions. (4) The composition and engine conditions of fuel oils jointly affected pollutant formation mechanisms. MGO and HFO exhibited opposite EC emissions when emitting the same level of PAHs.

Generation and emission mechanism of polycyclic aromatic hydrocarbon (PAHs) during the coking process in Shanxi, China.

Although coking process is the important source of polycyclic aromatic hydrocarbons (PAHs) in the environment, the generation and emission of PAHs during this process is unclear. It is crucial to clarify the formation mechanism of PAHs in coal pyrolysis during the coking process for effectively identifying and controlling the emission of these organic pollutants. In this study, the combination of laboratory simulation and field sampling was used to analyze the mechanism of PAHs formation and emission in coking process. The release of PAHs from the pyrolysis process of coal blends used in coking plants was 1778.20 ± 111.95 µg · g-1, which was much higher than the content of free PAHs in raw coal (76.50 ± 12.46 µg · g-1). 3-ring PAHs were the most abundant components of free PAHs and pyrolysis-generated PAHs. PAH formation during pyrolysis of coal blends was primarily attributed to the cracking of the macromolecular structure of coal, with minimal influence of free PAHs in blended coal. The emission of PAHs from coal-charging was higher (62.93 ± 17.75 µg · m-3) than that from pushing of coke (11.79 ± 1.91 µg · m-3·, PC) and combustion of coke oven gas (5.53 ± 1.20 µg · m-3, CG), and was mainly related to free PAHs in coal. In contrast, the characteristics of PAHs in the flue gas of PC and CG were similar to those from blended coal pyrolysis. PAHs in fugitive emission from coke oven were primarily affected by flue gas leakage and were mainly related to coal pyrolysis and free PAHs in blended coal.

Phenanthrene-induced hyperuricemia with intestinal barrier damage and the protective role of theabrownin: Modulation by gut microbiota-mediated bile acid metabolism.

Hyperuricemia is prevalent globally and potentially linked to environmental pollution. As a typical persistent organic pollutant, phenanthrene (Phe) poses threats to human health through biomagnification. Although studies have reported Phe-induced toxicities to multiple organs, its impact on uric acid (UA) metabolism remains unclear. In this study, data mining on NHANES 2001-2016 indicated a positive correlation between Phe exposure and the occurrence of hyperuricemia in population. Subsequently, adolescent Balb/c male mice were orally exposed to Phe at a dosage of 10 mg/kg bw every second day for 7 weeks, resulting in dysfunction of intestinal UA excretion and disruption of the intestinal barrier. Utilizing intestinal organoids, 16S rRNA sequencing of gut microbiota, and targeted metabolomic analysis, we further revealed that an imbalance in bile acid metabolism derived from gut microbiota might mediate the intestinal barrier damage. Additionally, the tea extract theabrownin (TB) effectively improved Phe-induced hyperuricemia and intestinal dysfunction at a dose of 320 mg/kg bw per day. In conclusion, this study demonstrates that Phe exposure is positively associated with hyperuricemia and intestinal damage, which provides new insights into the toxic effects induced by Phe. Furthermore, the present study proposes that supplementation with TB would be a healthy and effective improvement strategy for patients with hyperuricemia and intestinal injury caused by environmental factors.

Intermolecular interaction energies with AROFRAG-A systematic approach for fragmentation of aromatic molecules.

Intermolecular interactions with polycyclic aromatic hydrocarbons (PAHs) represent an important area of physisorption studies. These investigations are often hampered by a size of interacting PAHs, which makes the calculation prohibitively expensive. Therefore, methods designed to deal with large molecules could be helpful to reduce the computational costs of such studies. Recently we have introduced a new systematic approach for the molecular fragmentation of PAHs, denoted as AROFRAG, which decomposes a large PAH molecule into a set of predefined small PAHs with a benzene ring being the smallest unbreakable unit, and which in conjunction with the Molecules-in-Molecules (MIM) approach provides an accurate description of total molecular energies. In this contribution we propose an extension of the AROFRAG, which provides a description of intermolecular interactions for complexes composed of PAH molecules. The examination of interaction energy partitioning for various test cases shows that the AROFRAG3 model connected with the MIM approach accurately reproduces all important components of the interaction energy. An additional important finding in our study is that the computationally expensive long-range electron-correlation part of the interaction energy, that is, the dispersion component, is well described at lower AROFRAG levels even without MIM, which makes the latter models interesting alternatives to existing methods for an accurate description of the electron-correlated part of the interaction energy.