Polycyclic Hydrocarbons Research Articles

Biocatalytic Potential of Pseudomonas Species in the Degradation of Polycyclic Aromatic Hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs), one of the major environmental pollutants, produced from incomplete combustion of materials like coal, oil, gas, wood, and charbroiled meat, that contaminate the air, soil, and water, necessitating urgent remediation. Understanding the metabolic pathways for PAHs degradation is crucial to preventing environmental damage and health issues. Biological methods are gaining increasing interest due to their cost-effectiveness and environmental friendliness. These methods are particularly suitable for remediating PAHs contamination and mitigating associated risks. The paper also outlines the processes for biodegrading PAHs, emphasizing the function of Pseudomonas spp., a kind of bacterium recognized for its capacity to degrade PAHs. To eliminate PAHs from the environment and reduce threats to human health and the environment, Pseudomonas spp. is essential. Understanding the mechanism of PAH breakdown by means of microbes could lead to effective clean-up strategies. The review highlights the enzymatic capabilities, adaptability, and genetic versatility of the genes like nah and phn of Pseudomonas spp., which are involved in PAHs degradation pathways. Scientific evidence supports using Pseudomonas spp. as biocatalysts for PAHs clean-up, offering cost-effective and eco-friendly solutions.

Using Four Machine Learning Methods to Analyze the Association Between Polycyclic Aromatic Hydrocarbons and Visual Impairment in American Adults: Evidence from NHANES

The causes of visual impairment are complex and may be influenced by exposure to environmental pollutants. Using data from the 2003–2004 National Health and Nutrition Examination Survey (NHANES), we examined the association between exposure to ten polycyclic aromatic hydrocarbons (PAHs) and vision problems in 1149 U.S. adults. We employed various supervised learning methods, including variable selection techniques such as Lasso and elastic net, weighted quantile sum regression (WQS), and Bayesian kernel machine regression (BKMR), to assess the association between PAHs and the occurrence of visual impairments. The mediation effects between urinary 2-fluorene and inflammation were evaluated using mediation analysis. Both the lasso and elastic net models consistently identified two specific PAH congeners, 2-fluorene and 1-phenanthrene, as significant predictors. The WQS regression revealed a positive relationship between the PAH mixture and visual impairment, with notable contributions from urinary 2-fluorene (weight = 0.39) and 9-fluorene (weight = 0.21). BKMR analysis indicated that the likelihood of visual impairment increases with higher PAH exposure, showing a general upward trend. This trend also revealed a positive association between visual impairment and exposure to four specific PAH metabolites, including 2-fluorene. A significant mediation effect was observed for alkaline phosphatase (p = 0.03), with a proportion mediated of 10.48%. Our findings suggest a significant association between PAHs and visual impairment, with multiple statistical models consistently emphasizing the crucial role of 2-fluorene exposure. This study highlights the importance of considering environmental pollutants as significant contributors to visual health outcomes, providing insights for preventing visual impairment.

Content of Selected Harmful Metals (Zn, Pb, Cd) and Polycyclic Aromatic Hydrocarbons (PAHs) in Honeys from Apiaries Located in Urbanized Areas.

The chemical composition of honey, and therefore its quality and properties, is influenced by many factors, including its botanical origin and the harvesting conditions-the location of the apiary, access to melliferous plants, the proximity of industrial infrastructure and communication routes, etc. This quality may be reduced by undesirable, toxic compounds that penetrate honey from a contaminated environment, such as heavy metals and residues from other environmental pollutants. Therefore, the aim of our research was to assess the quality of honeys from urbanized areas-in particular, to assess contamination with heavy metals and persistent organic pollutants (PAHs). In total, 35 samples from six different apiaries located in urbanized areas were examined. The content of heavy metals (Cd, Pb, Zn) was determined by atomic absorption spectrophotometry (AAS), and the content of total PAHs as the sum of the concentrations of the compounds benzo(a)anthracene, chrysene, benzo(b)fluoranthene and benzo(a)pyrene was determined by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The average zinc content ranged from about 2 to 4.5 mg/kg, the average lead content ranged from 3.5 µg/kg to 388 µg/kg and the average cadmium content ranged from 0.5 to 14 µg/kg. It was found that all honeys contained certain amounts of harmful metals, and only lead exceeded the permissible limits. None of the samples tested contained sum content of PAHs exceeding 10 µg/kg of honey. Contrary to our expectations, the results obtained indicate that honeys from urbanized areas do not contain these harmful substances. In general, the presence of harmful metals does not, however, reduce honey's quality or its health value.

Syntheses and Properties of Two Isomeric Phenanthroacephenanthrylene Derivatives

Cyclopenta‐annulated polycyclic aromatic hydrocarbons (CP‐PAHs) are of significant interest due to their unique optoelectronic properties and applications in organic electronic devices. Phenanthroacephenanthrylene (PAP) isomers are CP‐PAHs that have been rarely investigated, and only the [9,10‐e]PAP isomer was explored to date. Herein, we report the syntheses, crystal structure and optoelectronic properties of two PAP isomers, 7‐ethoxy[2,1‐e]PAP 1 and 9‐ethoxy[1,2‐e]PAP 2. The structural isomers were synthesized in multi‐steps, and structural elucidations were performed using NMR, mass, and single‐crystal X‐ray diffraction analyses, revealing planar backbone of the isomers. UV‐visible absorption and fluorescence spectra of compound 1 were red‐shifted than that of 2, suggesting smaller HOMO–LUMO energy gap which is further validated by DFT calculations that suggested the lowering of HOMO–LUMO spacing could be attributed to the greater destabilization of HOMO for 1.

Strategies for Hydrocarbon Removal and Bioleaching-Driven Metal Recovery from Oil Sand Tailings

Oil sand tailings from bitumen extraction contain various contaminants, including polycyclic aromatic hydrocarbons, BTEX, and naphthenic acids, which can leak into surrounding environments, threatening aquatic ecosystems and human health. These tailings also contribute to environmental issues such as habitat disruption and greenhouse gas emissions. Despite these challenges, oil sand tailings hold significant potential for waste-to-resource recovery as they contain valuable minerals like rare earth elements (REEs), titanium, nickel, and vanadium. Traditional metal extraction methods are environmentally damaging, requiring high energy inputs and generating dust and harmful emissions. Furthermore, the coating of hydrocarbons on mineral surfaces presents an additional challenge, as it can inhibit the efficiency of metal extraction processes by blocking access to the minerals. This highlights the need for alternative, eco-friendly approaches. Bioleaching, which uses microorganisms to extract metals, emerges as a sustainable solution to unlock the valuable metals within oil sand tailings. This review discusses the minerals found in oil sand tailings, the challenges associated with their extraction, methods from hydrocarbon removal from minerals, and bioleaching as a potential metal recovery method.

Schools and Indoor Air Quality: seasonal variation

Abstract Background Indoor Air Quality (IAQ) in schools is a public health concern, given the vulnerability of children as a demographic group and substantial amount of time that they spend in (highly occupied) classrooms. Conditions specific for school buildings, as well as location and outdoor air quality (OAQ), can adversely affect IAQ and children’s health. The aim of this study was to examine the seasonal variation in IAQ and the influence of OAQ herein in primary schools. Methods Sampling was carried out in summer and winter in 5 schools in central Poland. A culture-dependent method using impactors was applied to examine the total number of bacteria and fungi. Gas chromatography with flame ionization detector (quartz filters for sampling) was applied to determine concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), crucial for their health impact. Results In poorly ventilated classrooms bacteria levels exceeded that of fungi. Bacterial contamination decreased in efficiently ventilated rooms, and before/after the lessons. In summer fungi concentration in indoor air was higher than in winter and reached the level of fungi outdoors. PAHs concentrations (especially those with 4 and more rings, which are biologically active) and the mutagenicity and carcinogenicity equivalents were elevated in winter and related to changes in concentrations in outdoor air. Conclusions IAQ in schools depends on a season. Occupants in classrooms are the main source of bacteria, but the type and number of microorganisms also depend on ventilation conditions. PAHs characteristic of coal/wood combustion indicates that in the absence of internal emission sources, external sources most likely affect IAQ in schools in winter.

Detection and analysis of ship emissions using single-particle mass spectrometry: A land-based field study in the port of rostock, Germany

The regulation of ship emissions has become more restrictive due to their significant impact on global air quality, particularly in coastal regions. According to the International Maritime Organization (IMO) regulations, current restrictions mainly limit the sulfur content of the fuel mass to 0.5 % and 0.1 % respectively. In compliance with these regulations, exhaust SO2 cleaning systems (scrubbers) and new low-sulfur fuels are increasingly used. For comprehensive monitoring of ship emissions, advanced measurement techniques are demanded. Our study reports on the results of a land-based field campaign conducted in the port of Rostock, Germany. The chosen location strategically positions the measurement setup to capture all incoming and outgoing ships passing within a distance of up to 2 km. Potential ship exhaust plumes are indicated by rapid changes in particle number and size distribution monitored by an optical particle sizer (OPS) and a scanning mobility particle sizer (SMPS). Additionally, single-particle mass spectrometry (SPMS) was used to qualitatively characterize ambient single-particles (0.2–2.5 μm) by their chemical signatures. In a one-week time span, the exhaust plumes of 73 ships were identified. The high sensitivity of SPMS to transition metals and polycyclic aromatic hydrocarbons (PAH) in individual particles make it possible to distinguish between different marine fuels.

Analyzing the modified symmetric division deg index: mathematical bounds and chemical relevance

Abstract The modified symmetric division deg (MSD) index of a graph G is precisely defined as MSD ( G ) = ∑ j ∼ k 1 2 d j d k + d k d j , where d j and d k represent the degrees of j and k respectively. In this paper, we present precise bounds for the modified symmetric division deg index, expressed in the relation to the minimum and maximum degrees, the order and size of the graph, the number of pendant vertices and the minimum degree of a non-pendant vertex, the forgotten topological index, the modified second Zagreb index. We determine the upper bounds for the modified symmetric division deg index of unicyclic, bicyclic and k-cyclic graphs. Moreover, upon analyzing the modified symmetric division deg index, we observe its correlation with other well-known indices and its chemical applicability on the molecular graphs of octane isomers. At the end, we find the chemical applicability of the modified symmetric division deg index on benzenoid hydrocarbons and observe that the modified symmetric division deg index has a very strong correlation with the physical properties of benzenoid hydrocarbons.

Exploring the potential of biosurfactants produced by fungi found in soil contaminated with petrochemical wastes

Biosurfactants are a diverse group of compounds derived from microorganisms, possessing various structures and applications. The current study was seeking to isolate and identify a new biosurfactant-producing fungus from soil contaminated with petrochemical waste. The bioprocess conditions were optimized to maximize biosurfactant production for Aspergillus carneus OQ152507 using a glucose peptone culture medium with a pH of 7.0 and a temperature of 35 °C. The carbon source was glucose (3%), and ammonium sulfate (0.25%) was utilized as the nitrogen source. For Aspergillus niger OQ195934, the optimized conditions involved a starch nitrate culture medium with a pH of 7.0 and a temperature of 30 °C. The carbon source used was sucrose (3.5%), and ammonium sulfate (0.25%) served as the nitrogen source. The phenol-H2SO4 and phosphate tests showed that the biosurfactants that were extracted did contain glycolipid and/or phospholipid molecules. They showed considerable antimicrobial activity against certain microbes. The obtained biosurfactants increased the solubility of tested polyaromatic hydrocarbons, including fluoranthene, pyrene, anthracene, and fluorine, and successfully removed the lubricating oil from contaminated soil and aqueous media surface tension reduction. Based on the obtained results, A. carneus and A. niger biosurfactants could be potential candidates for environmental oil remediation processes.

Environmental Impact and Decompsition of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Soils: Challenges and Future Directions

The rapid pace of urbanization and development has led to an increasing global concern over polycyclic aromatic hydrocarbons (PAHs) due to their persistent and widespread presence in the environment, posing significant threats to ecosystems and human health. PAHs originate from both natural and human-made sources and can be categorized based on their origin into pyrogenic, petrogenic, and biogenic products. Upon entering the environment, PAHs undergo various chemical and biological transformations, and their movement occurs through processes such as air-to-soil and soil-to-air transport. Composting, a green and cost-effective technology, offers a promising solution for PAH remediation. This process, which includes mesophilic, thermophilic, cooling, and maturing stages, can yield compost that is useful as fertilizer and soil amendment in agriculture. The success of composting depends on factors such as substrate bioavailability, oxygen levels, nutrient supply, and environmental conditions. While composting has shown effectiveness in reducing PAH levels, it is not without challenges, including the risk of weed infestation, greenhouse gas emissions, and odor pollution. The main obstacles in PAH remediation today are the limited bioaccessibility of PAHs and the insufficient focus on the formation of oxygenated PAHs during the process. Future research should address these challenges, particularly by improving PAH bioaccessibility and mitigating issues related to odor and greenhouse gas emissions.

Determination of PAH Contamination in Breast Milk Samples from Hungarian Volunteering Mothers, Using HPLC-FLD.

(1) The evidence is mounting that polycyclic aromatic hydrocarbons (PAHs) are a class of hazardous organic compounds with established carcinogenic and toxic properties. Humans may be exposed to PAHs through several different routes, including diet, inhalation, and dermal contact. There is also a possibility that they could transfer into breast milk following maternal exposure, which could potentially endanger breastfeeding infants. (2) The objective of this study was to ascertain the concentration of polycyclic aromatic hydrocarbons (PAHs) in breast milk samples from 50 Hungarian mothers, employing high-performance liquid chromatography with fluorescence detection (HPLC-FLD). An Incremental Life Risk Calculation (IRCL) model estimated the carcinogenic risk to infants. (3) Total PAH concentrations ranged from 0 to 78 ng/mL, with fluorene (5.3 ng/mL), phenanthrene (3.2 ng/mL), and pyrene (2.5 ng/mL) being the most abundant. PAHs were detected in 48 of the 50 samples, with phenanthrene present in 92% of samples. Dibenzo (a,h)anthracene was not detected. (4) According to the model measurements, most of the samples were within acceptable risk levels; however, 2 samples out of 50 posed a higher risk. Statistical analysis of questionnaires completed by the mothers indicated that factors such as diet, residence, and education may influence PAH levels in breast milk.

Non-target screening analysis of hazardous noxious substances using gas chromatography-quadrupole time-of-flight mass spectrometry

The forensic investigation of hazardous noxious substances (HNS) is paramount for an effective response to chemical spill emergencies and other accidents. Analyzing unknown emergency samples poses a challenge due to the limited availability of background information, making the selection of appropriate sample preparation and analytical methodologies difficult. The utilization of high-resolution mass spectrometers (HRMS) in screening both target and non-target substances proves instrumental in revealing hazardous substances that may be overlooked alongside the intended analytes. In this study, a gas chromatography-quadruple time-of-flight mass spectrometer (GC-QTOF-MS) was employed to identify numerous organic compounds in an indoor dust sample. The compounds detected encompassed normal alkanes, fatty acids (saturated and unsaturated), alcohols, phenols, sterols, drugs, polycyclic aromatic hydrocarbons (PAHs), pesticides, flame retardants (such as polybrominated biphenyl ethers, PBDEs), plasticizers (such as phthalates and phosphates), among others. Notably, concentrations of n-alkanes, fatty acids, and phthalates were relatively high, while PAHs and pesticides were present at trace levels. The application of GC-QTOF-MS provides a swift and confirmative approach for analyzing target, suspect, and non-target compounds in both routine and emergency scenarios. This methodology proves invaluable in enhancing our capability to comprehensively assess and address chemical incidents, ensuring a more thorough and accurate response.

Optimizing predictive models for evaluating the F-temperature index in predicting the π-electron energy of polycyclic hydrocarbons, applicable to carbon nanocones

In the fields of mathematics, chemistry, and the physical sciences, graph theory plays a substantial role. Using modern mathematical techniques, quantitative structure-property relationship (QSPR) modeling predicts the physical, synthetic, and natural properties of substances based only on their chemical composition. For a chemical graph, the temperature of a vertex is a local property introduced by Fajtlowicz (1988). A temperature-based graphical descriptor is structured based on temperatures of vertices. Involving a non-zero real parameter β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta$$\\end{document}, the general F-temperature index Tβ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{\\beta }$$\\end{document} is a temperature index having strong efficacy. In this paper, we employ discrete optimization and regression analysis to find optimal value(s) of β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta$$\\end{document} for which the prediction potential of Tβ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{\\beta }$$\\end{document} and the total π\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pi$$\\end{document}-electron energy Eπ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E_{\\pi }$$\\end{document} of polycyclic hydrocarbons is the strongest. This, in turn, answers an open problem proposed by Hayat & Liu (2024). Applications of the optimal values for Tβ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{\\beta }$$\\end{document} are presented a two-parametric family of carbon nanocones in predicting their Eπ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E_{\\pi }$$\\end{document} with significantly higher accuracy.

The tight correlation between PAH and CO emission from z ∼ 0 to 4

Aims. The cold molecular gas mass is one of the crucial, yet challenging, parameters in galaxy evolution studies. Here, we introduce a new calibration and a method for estimating molecular gas masses using mid-infrared (MIR) photometry. This topic is timely as the James Webb Space Telescope (JWST) now allows us to detect the MIR emission of typical main-sequence galaxies across a wide range of masses and star formation rates with modest time investments. Additionally, this Letter highlights the strong synergy between ALMA and JWST for studies of dust and gas at cosmic noon. Methods. We combined a sample of 14 main-sequence galaxies at z = 1 − 3 with robust CO detections and multi-band MIR photometry, along with a literature sample at z = 0 − 4 with CO and polycyclic aromatic hydrocarbon (PAH) spectroscopy, to study the relationship between PAH, CO(1–0), and total IR luminosities. PAH luminosities are derived by modelling a wealth of rest-frame UV to sub-millimetre data. The new z = 1 − 3 sample extends previous high-z studies to PAH and CO luminosities that are about an order of magnitude lower, into the regime of local starbursts, for the first time. Results. The PAH-to-CO luminosity ratio remains constant across a wide range of luminosities, for various galaxy types, and throughout the explored redshift range. In contrast, the PAH-to-IR and CO-to-IR luminosity ratios deviate from a constant value at high IR luminosities. The intrinsic scatter in the L(PAH)–L′(CO) relation is 0.21 dex, with a median of 1.40 and a power-law slope of 1.07 ± 0.04. Both the PAH–IR and CO–IR relations are sub-linear. Given the tight and uniform PAH–CO relation over ∼3 orders of magnitude, we provide a recipe for estimating the cold molecular gas mass of galaxies from PAH luminosities, with a PAH-to-molecular gas conversion factor of αPAH7.7 = (3.08 ± 1.08)(4.3/αCO) M⊙/L⊙. This method opens a new window to explore the gas content of galaxies beyond the local Universe using multi-wavelength JWST/MIRI imaging.

Chronic exposure to polycyclic aromatic hydrocarbons alters skin virome composition and virus-host interactions.

Exposure to polycyclic aromatic hydrocarbons (PAHs) in polluted air influences the composition of the skin microbiome, which in turn is associated with altered skin phenotypes. However, the interactions between PAH exposure and viromes are unclear. This study aims to elucidate how PAH exposure affects the composition and function of skin viruses, their role in shaping the metabolism of bacterial hosts, and the subsequent effects on skin phenotype. We analyzed metagenomes from cheek skin swabs collected from 124 Chinese women in our previous study and found that the viruses associated with the two microbiome cutotypes had distinct diversities, compositions, functions, and lifestyles following PAH exposure. Moreover, exposure to high concentrations of PAHs substantially increased interactions between viruses and certain biodegrading bacteria. Under high-PAH exposure, the viruses were enriched in xenobiotic degradation functions, and there was evidence suggesting that the insertion of bacteriophage-encoded auxiliary metabolic genes into hosts aids biodegradation. Under low-PAH exposure conditions, the interactions followed the "Piggyback-the-Winner" model, with Cutibacterium acnes being "winners," whereas under high-PAH exposure, they followed the "Piggyback-the-Persistent" model, with biodegradation bacteria being "persistent." These findings highlight the impact of air pollutants on skin bacteria and viruses, their interactions, and their modulation of skin health. Understanding these intricate relationships could provide insights for developing targeted strategies to maintain skin health in polluted environments, emphasizing the importance of mitigating pollutant exposure and harnessing the potential of viruses to help counteract the adverse effects.

Impact of dissolved/dispersed oil from a spill event on the development of embryos of the snapping shrimp Alpheus estuariensis (Caridea: Alpheidae)

This study characterized polycyclic aromatic hydrocarbons (PAHs) in oil pellets stranded at Fernando de Noronha Archipelago, equatorial Atlantic. It also characterized PAHs dissolved/dispersed in seawater (i.e. water accommodated fraction - WAF) and used them for investigating toxic effects on embryos of the snapping shrimp Alpheus estuariensis. In the experiment, WAF was diluted to six concentrations – 0 %, 20 %, 40 %, 60 %, 80 % and 100 %. A total of 28 embryonated eggs were exposed to each dilution for 7 days under controlled conditions. Daily, four embryos from each treatment were removed for a detailed examination. Among the 16 priority PAHs, 12 of them were detected in the samples. There was a statistically significant correlation concerning embryo mortality over time across all dilutions, except for the control (0 % WAF). It can be concluded that embryo development is affected by increasing WAF concentration and exposure time. These results demonstrate that WAF directly affects larval development and cause significant mortality after one day of exposure.

Environmental Pollutant Anthracene Induces ABA-Dependent Transgenerational Effects on Gemmae Dormancy in Marchantia polymorpha.

Anthracene, a polycyclic aromatic hydrocarbon (PAH) from fossil fuel combustion, poses significant environmental threats. This study investigates the role of abscisic acid (ABA) in the anthracene tolerance of the liverwort Marchantia polymorpha using mutants deficient in ABA perception (Mppyl1) or biosynthesis (Mpaba1). In this study, we monitored the role of ABA in the anthracene tolerance response by tracking two ABA-controlled traits: plant growth inhibition and gemmae dormancy. We found that the anthracene-induced inhibition of plant growth is dose-dependent, similar to the growth-inhibiting effect of ABA, but independent of ABA pathways. However, gemmae dormancy was differentially affected by anthracene in ABA-deficient mutants. We found that gemmae from anthracene-exposed WT plants exhibited reduced germination compared to those from mock-treated plants. This suggests that the anthracene exposure of mother plants induces a transgenerational effect, resulting in prolonged dormancy in their asexual propagules. While Mppyl1 gemmae retained a dormancy delay when derived from anthracene-exposed thalli, the ABA biosynthesis mutant Mpaba1 did not display any significant dormancy delay as a consequence of anthracene exposure. These results, together with the strong induction of ABA marker genes upon anthracene treatment, imply that anthracene-induced germination inhibition relies on ABA synthesis in the mother plant, highlighting the critical role of MpABA1 in the tolerance response. These findings reveal a complex interplay between anthracene stress and ABA signaling, where anthracene triggers ABA-mediated responses, influencing reproductive success and highlighting the potential for leveraging genetic and hormonal pathways to enhance plant resilience in contaminated habitats.

Biomarker and adverse outcome pathway responses of Tubifex tubifex(sludge worm) exposed to environmentally-relevant levels of acenaphthene: insights from behavioral, physiological, and chemical structure-activity analyses.

Polycyclic aromatic hydrocarbons (PAHs), including acenaphthene, pose a significant threat to aquatic ecosystems by harming vital organisms such as benthic invertebrates. This study evaluated the impact of environmentally relevant concentrations of acenaphthene on Tubifex tubifex, focusing on sublethal acute toxicity and subchronic biomarker responses. Key biomarkers assessed included histopathological changes and the modulation of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and malondialdehyde (MDA). Additionally, the study examined structure-activity relationships and species sensitivity distribution (SSD). Concentrations exceeding the solubility threshold of acenaphthene (3.9 mg/L) triggered distinct, concentration-dependent behavioral responses in Tubifex tubifex, such as clumping, mucus secretion, and body wrinkling. Prolonged exposure exacerbated these behavioral dysfunctions, while subchronic exposure resulted in significant histopathological alterations, including epithelial hyperplasia, inflammation, edema, fibrosis, and degenerative changes. The edematic appearance of the body wall suggested a potential immune response to exposure. Furthermore, increased activities of CAT, SOD, and GST indicated oxidative stress in the worms. The study found a 1.5-fold increase in CAT and GST activity, a fivefold increase in SOD, and a striking 100-fold increase in MDA levels compared to controls, signifying an overwhelmed antioxidant defense system and potential cellular disruption. The SSD curve revealed hazard concentrations (HC50 and HC90), indicating that Tubifex tubifex exhibited lower sensitivity to acenaphthene compared to other taxa. In silico analysis and read-across models confirmed the potential of acenaphthene to induce significant oxidative stress upon exposure. The correlation between biomarker responses and structure-activity relationship analysis highlighted the aromatic nature of acenaphthene as a key factor in generating reactive metabolites, inhibiting antioxidant enzymes, and promoting redox cycling, ultimately contributing to adverse outcomes. These findings, coupled with behavioral responses and SSD curve inferences, underscore the importance of the solubility threshold of acenaphthene as a critical benchmark for evaluating its ecological impact in aquatic environments.

Evaluating the efficiency of oil waste treatment plant in AL- Qayyarah Refinery - Iraq

The study included an evaluation of the efficiency of AL-Qayyarah refinery oil waste treatment plant. For this purpose, monthly samples were collected for a period of six months from October 2023 until March 2024, the first station (before treatment) represents the water coming out of the crude oil filter units. As for the second station (after treatment) it is located in the refinery waste treatment unit, the site represents the treated water. many physical and chemical tests were conducted on water, they ranged of temperature values ​​before the treatment ranged between (17-33) compared to its value after the treatment (15-31), and the electrical conductivity values ​​before the treatment ranged between (295-405)µS/cm, while after the treatment it was (349-471)µS/cm. As for total dissolved solids, their average before the treatment was(182.5)mg/L, while their average after the treatment was(194.6)mg/L as for salinity, its values ​​ranged between(0.7-0.75) mg/L before the treatment and between (0.6 -0.8) mg/L after the treatment ,pH value before the treatment was between)6.12- 7.91( compared to its value after the treatment as it ranged between (6.81-7.95), while the values ​​of the chemical requirement for oxygen before the treatment were (85108)mg/L, Their concentrations values ​​after the treatment amounted to(73_125) mg/L, and polycyclic aromatic hydrocarbons (PAHs) (73.46-155.17) mg/L before the treatment, and after the treatment it reached (35.53-52.53) mg/L, while oils and greases reached values ​​that ranged between (26.16-165.68) mg/L before the treatment compared to their results after the treatment which ranged between (94.15-23.18)mg/L. Finally, the total organic carbon had an average value before treatment (134.1) mg/L, while after treatment their average values ​​reached (120.8) mg/L

Effect of Sulfur Contents on Polycyclic Aromatic Compounds in Low-Rank Bituminous Coals

Different coal seams go through distinct biological, physical, and chemical processes. Polycyclic aromatic compounds (PACs) in coal may retain information about these processes, especially in low-rank bituminous coals. Three coal seams with different sulfur contents from the Ningwu Coalfield were studied to understand the relation of different sulfur contents with PAC formation in low-rank bituminous coals. Coal samples were extracted by solvent and separated using liquid chromatography. The collected aromatic hydrocarbon fractions were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 27 sulfur-containing PACs (SPACs) were identified in the high-sulfur samples, whereas only 8 SPACs were found in the low-sulfur coal and middle-sulfur coal. The total SPACs to total PACs ratios (T-SPACs/T-PACs) are 1.15%, 2.17%, and 10.65% in the low-sulfur, middle-sulfur, and high-sulfur coal, respectively. The variations of SPAC species and their content ratios indicate that SPAC formation is controlled by the sulfur contents in the low-rank bituminous coals. A total of 18 oxygen-containing PACs (OPACs) were identified in the low-sulfur coal and middle-sulfur coal, whereas only 11 OPACs were found in the high-sulfur samples. The average ratios of OPACs to the identified aromatic compounds (T-OPACs/T-PACs) are 9.81%, 9.62%, and 6.91% in the low-, middle-, and high-sulfur coals, exhibiting a negative correlation with sulfur contents and indicating that OPACs were also influenced by sulfur contents in low-rank bituminous coals. The ratios of total contents of polycyclic aromatic hydrocarbons (PAHs) to total PACs (T-PAHs/T-PACs) are 89.1%, 88.2%, and 82.0% in the low-, middle-, and high-sulfur coals, respectively, indicating a decreasing trend from low- and middle-sulfur coal to high-sulfur coal. This variation could be caused by the reaction of PAHs and sulfur to form SPACs.