Search Results (350)

This paper presents the results of a laboratory-based treatability study conducted for a confidential former wood treating site heavily impacted by a creosote non-aqueous-phase liquid (NAPL) containing pentachlorophenol (PCP). PCP impacts in the silty sands extended to approximately 33 ft (10 m) below the ground surface (bgs), with discrete soil samples containing PCP concentrations up to 14,500 mg/kg, and groundwater PCP concentrations forming a main plume exceeding 1 mg/L over 2.16 acres (0.87 ha). Treatability testing was performed on unspiked and NAPL-spiked site soils with total PCP concentrations ranging from 10 to 100 mg/kg, respectively, and leachable PCP concentrations of approximately 3 to 8 mg/L. Stabilization/solidification (S/S) mix designs using 5 to 10 weight percent (wt%, dry-reagent-to-wet-soil mass basis) of a Portland cement (PC) blend and 1 wt% powdered bentonite met the minimum unconfined compressive strength (UCS) and maximum hydraulic conductivity (K) performance criteria of 50 lb/in2 (345 kPa) and 1 × 10⁻⁶ cm/s, respectively, within the specified 28-day cure time. Long-term semi-dynamic leach testing was performed on S/S-treated soils using a modified United States Environmental Protection Agency (EPA) Method 1315 test incorporating a polydimethylsiloxane (PDMS) liner to improve the data reliability for hydrocarbons. Results showed that adding 1 wt% organoclay (OC) to the S/S mix designs did not substantially reduce leaching of common semi-volatile organic compounds (SVOCs) such as naphthalene, acenaphthene, phenanthrene and benzo(a)anthracene compared to mixes using only the PC blend with bentonite, consistent with previous studies. However, the inclusion of OC had a decisive effect on PCP immobilization, providing an order-of-magnitude (10×) reduction in the cumulative mass release of PCP over the test duration. This benefit diminished with decreasing degree of chlorination for other phenolic compounds. Full article

Polycyclic aromatic hydrocarbons (PAHs) are widely prevalent harmful organic pollutants. Enzymatic activities (such as those of dehydrogenases, catalase, protease and urease), as well as the microbial community structure and assembly (through 16S and ITS amplicon sequencing), were evaluated 90 days after PAH contamination and compared to those in normal soils. Microbial activity, as indicated by soil urease, catalase, and protease activities, was inhibited under PAH stress. Furthermore, PAH stress exerted significant impacts on the soil microbial community structure. Notably, PAH stress reduced soil bacterial and fungal biomass and inhibited the abundance of microbial taxa involved in soil carbon and nitrogen cycling (e.g., Marmoricola, Pedobacter, and Streptomyces), along with the majority of predicted responsive metabolic functions, particularly those related to amino acid and carbohydrate metabolism. PAH stress enriched PAH-degrading microorganisms, including Pseudomonas, Mycobacterium, Bacillus, Cycloclasticus, and Flavobacterium. The niche breadth of bacterial and fungal communities decreased significantly under PAH stress (51.5 and 14.1, respectively) compared to that in normal soil (63.7 and 22.3), which was further supported by Beta Nearest Taxon Index and co-occurrence network analysis. PAH stress increased the contribution of heterogeneous selection to soil microbial assembly (100%) compared to that in normal soil (80%). Thus, the majority of microbial community responses to PAH stress were adversely affected. These results suggest that PAH contamination may profoundly affect the soil quality by restricting the survival space of bacteria and fungi. Full article

Lignite collected from a brown coal deposit was colonized with fully aerobic bacteria exhibiting hydrocarbon biodegradation pathways. Six autochthonous strains were isolated and tested for tolerance and biotransformation potential towards various xenobiotics such as hexadecane, squalane, pristane, benzoic acid, naphthalene, phenanthrene, and diesel oil. After preliminary screening, four xenobiotic-resistant strains were selected (Rhodococcus opacus CUP11, Pseudomonas fluorescens CUP15, Sphingobacterium sp. CUP16, and Rhodococcus sp. CUP17) and further treated for 14 days under aerobic conditions with variant concentrations of each compound (1, 2.5, 5 and 10 g/dm³). Microbial population dynamics and xenobiotic level changes were monitored. Rhodococcus opacus CUP11 and Rhodococcus sp. CUP17 were the most metabolically versatile bacteria capable of biotransforming several xenobiotics. Among the best-performing strains, the highest degradation yields were obtained for CUP17 (81% removal of diesel oil applied at 10 g/dm³, 99% of 2.5 g/dm³ hexadecane and 27% of 1 g/dm³ squalane), and CUP11 (49% of 10 g/dm³ hexadecane and 48% of 1 g/dm³ pristane). The strain CUP16 utilized squalane (33% at 1 g/dm³). The results suggest that the lignite-indigenous bacteria may be applicable for bioremediation of persistent xenobiotics in environmental cleanup projects. Full article

In this study, the gradient pressure enrichment method was first used to screen out an environmental bacterium with the degradation ability of typical petroleum hydrocarbons such as phenanthrene and n-hexadecane, identified as Pseudomonas and named TB-1, from soil samples collected from 9 crude oil-contaminated sites; then, enhanced degradation of mixed organic pollutants, including petroleum and chlorinated hydrocarbons which are commonly coexistent, was achieved by a dual-bacteria system, with the addition of a laboratory storage strain Pseudomonas BL5. The degradation rate of phenanthrene and n-hexadecane by the dual-bacteria system was lower compared with the single bacterium Pseudomonas TB-1 under the tested conditions: phenanthrene degradation decreased from 44.2% to 23.1%, and n-hexadecane degradation decreased from 77.9% to 54.7% at a pollutant concentration of 100 mg/L after 7 days of cultivation. In contrast, the degradation ability of the dual-bacteria system against the mixed pollutants composed of petroleum and chlorinated hydrocarbons was good, with a degradation rate of 82.2% for phenanthrene, 89.2% for n-hexadecane, 73.1% for p-chlorobenzene, and 95.7% for dichloroethane with each concentration of 100 mg/L after 7 days. These results indicate that, although the dual-bacteria system does not enhance degradation under single-hydrocarbon conditions, its performance under chemically complex co-contamination suggests a potential cooperative or complementary interaction between the two strains. Such interactions are proposed here as a working hypothesis rather than a confirmed mechanism. Overall, the defined dual-Pseudomonas system shows promising potential for the treatment of environments co-contaminated with petroleum and chlorinated hydrocarbons. Full article

Benzodichalcogenophenes represent a valuable class of organic π-conjugated systems that have been investigated in a plethora of cutting-edge applications in the field of materials chemistry. Isomeric benzodifuran (BDF), benzodithiophene (BDT) and benzodiselenophene (BDS) analogs of phenanthrene, in which the two heteroaromatic rings are ortho-fused onto a benzene ring, represent convenient frameworks as functional materials in organic electronics. The orientation of the two condensed heteroaromatic rings with respect to the central benzene ring provides diverse structural isomers, which significantly differ in degrees of curvature, electronic and electrochemical properties. Furthermore, tailored modification and functionalization strategies enable fine-tuning of their intrinsic properties, leading to unique systems. This review offers a comprehensive overview of synthetic methodologies for constructing isomeric BDF, BDT and BDS skeletons, alongside an analysis of their electrochemical properties as influenced by the nature of heteroatoms. Finally, the most relevant applications of these systems, ranging from optoelectronics, supramolecular chemistry, and emerging biological studies, are discussed, providing valuable insights for future research direction. Full article

Low-molecular-weight polycyclic aromatic hydrocarbons (LMW-PAHs), such as the 400 μM mixture of phenanthrene and fluorene used in this study, are prevalent environmental pollutants. Induction of epithelial–mesenchymal transition (EMT) by LMW-PAHs promote cell invasion and migration and contribute to disease pathogenesis. Long non-coding RNAs (lncRNAs) regulate gene expression by acting as competing endogenous RNAs (ceRNAs) that sequester microRNAs (miRNAs), a mechanism important for modulating EMT. Previously, regulation of the PI3K/AKT pathway and EMT in A549 cells are shown to occur through the hsa_circ_0039929/miR-15b-3p_R-1/FGF2 axis. Here, the functional role of the related LINC01376/miR-15b-3p_R-1/FGF2 axis in LMW-PAH-induced EMT was examined in A549 and H1299 cells. The miR-15b-3p_R-1 was downregulated, whereas LINC01376 and FGF2 were upregulated following LMW-PAH exposure. LINC01376 overexpression enhanced EMT, migration, and invasion. Interactions between miR-15b-3p_R-1 and FGF2, as well as direct binding of LINC01376 to miR-15b-3p_R-1, were confirmed experimentally. The results indicate that, in LMW-PAH-treated cells, LINC01376 functions as a ceRNA to sponge miR-15b-3p_R-1, thereby elevating FGF2 expression and promoting EMT, migration, and invasion. Identification of the LINC01376/miR-15b-3p_R-1/FGF2 regulatory axis highlighted as a key mechanism in LMW-PAH-driven EMT and suggests its potential as a therapeutic target in PAH-related pathologies. Full article

This study introduces an optimized and selective extraction methodology using dichloromethane/methanol (DCM/MeOH, 95:5, v/v) in combination with accelerated solvent extraction (ASE) for the targeted stilbenoid and phenanthrene derivatives from five orchid species: Cattleya nobilior (root), Cymbidium defoliatum (root and bulb), Dendrobium phalaenopsis (stem), Encyclia linearifolioides (leaf), and Phalaenopsis aphrodite (root). Sequential extraction was performed with hexane, followed by DCM/MeOH (95:5 and 1:1, v/v) under controlled temperatures (70 °C for hexane, 100 °C for DCM/MeOH), using three static cycles per stage. Chemical profiling by high-performance liquid chromatography with a diode-array-detector and tandem mass spectrometry (HPLC-DAD-MS/MS) enabled the identification of twenty specialized metabolites—seven stilbenoids and thirteen phenanthrenes—several reported here for the first time, including crepidatuol B, dendrosinen D, and coeloginanthridin. The analytical method showed excellent separation of structurally related phenolic compounds, demonstrating the efficiency of the extraction protocol and the selectivity of the solvent system. Many of the identification metabolites are known for cytotoxic, antioxidant, anti-inflammatory, and metabolic regulatory properties, while newly detected compounds remain unexplored and present promising candidates for future biological evaluation. The broad distribution of these metabolites across the studied orchids enhances the current understanding of their phytochemical diversity and suggests chemotaxonomic relevance within the Orchidaceae family. Importantly, the extraction strategy requires minimal plant material, offering ecological advantages when working with rare or endangered species. Overall, this environmentally conscious extraction approach provides a robust platform for metabolic discovery and supports future research in natural products chemistry, plant ecology, drug discovery, structure–activity relationships studies and biotechnological applications. Full article

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants recognized for their toxicological significance. Increasing evidence suggests that chronic exposure to low-molecular-weight PAHs (LMW-PAHs) contributes to heightened disease vulnerability and immune dysregulation, particularly among rural female populations. Recent studies have further linked a significant association between PAH exposure and gut microbiome (GM) modifications. Considering the common embryonic origin of the intestinal and respiratory systems, cross-organ communication under conditions of PAH exposure warrants deeper exploration. Although current gut–lung axis research largely emphasizes microbial metabolites such as short-chain fatty acids and bile acids, the contribution of arachidonic acid (AA) metabolites in LMW-PAH-induced pulmonary inflammation via this axis remains poorly defined. To address this knowledge gap, we developed an animal model employing integrated 16S rRNA sequencing and metabolomics approaches to systematically examine phenanthrene (Phe) and fluorene (Flu) induced GM compositional shifts and associated metabolic reprogramming. Through comprehensive profiling, we identified candidate microorganisms and metabolites potentially involved in dysbiosis-mediated pulmonary inflammation, thereby elucidating the mechanistic basis of Phe and Flu-associated health risks. Full article

This study explores the potential of two marine-derived bacteria, Cytobacillus kochii and Marinobacter, through in silico analysis of their catechol 2,3-dioxygenase (C23O) enzymes. Molecular docking simulations were conducted using AutoDock Vina to assess the binding interactions between C23O enzymes and ten hydrocarbon pollutants, including monocyclic and polycyclic aromatic hydrocarbons (PAHs). Binding affinities ranged from −4 to −8.7 kcal/mol for Cytobacillus kochii, with the highest affinity observed for fluoranthene (−8.7 kcal/mol), followed by pyrene (−8.5 kcal/mol) and phenanthrene (−8.2 kcal/mol). In comparison, Marinobacter’s C23O showed binding affinities between −4.1 and −8 kcal/mol, with fluoranthene (−8 kcal/mol) and phenanthrene (−7.9 kcal/mol) being top performers. Despite slightly lower affinity, Marinobacter exhibits superior environmental resilience under high salinity and temperature, making it valuable for application in fluctuating marine conditions. Structural interaction analysis revealed consistent pi-pi stacking and hydrogen bonding within the active sites, further supporting enzyme–substrate compatibility. These computational findings underscore Cytobacillus kochii ’s superior catalytic potential and Marinobacter’s ecological robustness. The integration of both strains into a microbial consortium offers a promising synergistic approach, combining enzymatic efficiency and environmental adaptability for effective hydrocarbon degradation. While these computational assessments offer valuable predictive insights, further validation through in vitro and in vivo experiments would be beneficial to determine the actual hydrocarbon degradation efficiencies. Full article

The use of floating wetlands has been receiving increased attention as a minimally invasive method for oil spill remediation, but the species of vegetation incorporated in floating wetlands may influence the success of oil degradation. Therefore, a freshwater microcosm experiment was conducted at the IISD Experimental Lakes Area, Canada to assess the potential of common wetland plants Typha sp., Carex utriculata, and C. lasiocarpa, to remove phenanthrene, a polycyclic aromatic hydrocarbon ubiquitously found at oil spill sites. Triplicate microcosms containing 3L of lake water were established with either Typha sp., Carex utriculata, or C. lasiocarpa and then treated with nominal concentration of 1 mg/L phenanthrene and monitored over 21 days. Two types of reference microcosms were also included: one set with the same plant allocations but not treated with phenanthrene and another with water only and no plants or phenanthrene. Phenanthrene declined by over 89.30% in all microcosms that received the compound, but the decline was more rapid in microcosms that included Typha sp. and C. lasiocarpa, than those with C. utriculate or no plants. Declining phenanthrene concentrations in microcosms without plants may have resulted from biofilm stimulation. Specific conductivity and pH were influenced by plant type but not phenanthrene, while dissolved oxygen was influenced by both. There was no influence of phenanthrene on plant growth rates or root biofilm bioactivity, measured by adenosine triphosphate or oxygen consumption. Results indicate there may be plant-specific factors influencing remediation success which should be explored in future research. Full article

Various surfactants have been applied for the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated environments, but their roles in bioremediation remain controversial. This study focused on rhamnolipid (a typical surfactant) and Burkholderia sp. FM-2 (a high-efficiency phenanthrene-degrading bacterium), investigating its effects on phenanthrene solubilization and biodegradation by analyzing cell surface characteristics and gene expression differences. Results showed that low concentrations of rhamnolipid (20–120 mg/L) promoted phenanthrene degradation, while high concentration (400 mg/L) exerted an inhibitory effect. At 20–56 mg/L, rhamnolipid altered the bacterial surface morphology and functional groups, facilitated lipopolysaccharide release, enhanced cell surface hydrophobicity, and increased zeta potential. When the rhamnolipid concentration was 20 mg/L, the phenanthrene degradation rates of cytoplasmic enzymes, periplasmic enzymes, and extracellular enzymes produced by the bacterium reached over 98% after 15 days of enzyme system culture, demonstrating its role in promoting enzyme production and activity. Transcriptomic analysis revealed that 56 mg/L (1 CMC) rhamnolipid enhanced degradation through multi-pathway regulation of gene expression: upregulating the gene encoding protocatechuate 3,4-dioxygenase to strengthen benzene ring cleavage; increasing the expression of genes related to ABC transporters and protein transport to promote phenanthrene transmembrane transport; and activating genes involved in metabolic processes such as pyruvate metabolism and the tricarboxylic acid (TCA) cycle to enhance central carbon metabolic flux. This regulatory mode optimizes energy supply and redox balance, and indirectly improves phenanthrene bioavailability by modulating membrane structure and function. Full article

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants with significant ecological and public health implications, particularly in urban wetlands exposed to chronic anthropogenic stress. This study evaluates the occurrence, spatial distribution, seasonal variability, and ecological risk of three low molecular weight PAHs—naphthalene (NAP), phenanthrene (PHEN), and anthracene (ANT)—in surface waters of Caño La Malaria, the main freshwater source of Cucharillas Marsh, Puerto Rico’s largest urban wetland. Surface water samples were collected at four locations during both wet- and dry-season campaigns. Samples were extracted and quantified by GC-MS. NAP was the dominant compound, Σ3PAHs concentrations ranging from 7.4 to 2198.8 ng/L, with higher wet-season levels (mean = 745.79 ng/L) than dry-season levels (mean = 186.71 ng/L); most wet-season samples fell within the mild-to-moderate contamination category. Compositional shifts indicated increased levels of PHEN and ANT during the wet season. No significant spatial differences were found (p = 0.753), and high correlations between sites (r = 0.96) suggest uniform input sources. Diagnostic ratios, inter-species correlations, and principal component analysis (PCA) consistently indicated a predominant pyrogenic origin, with robust PHEN–ANT correlation (r = 0.824) confirming shared combustion-related sources. PCA revealed a clear separation between dry- and wet-season samples, with the latter showing greater variability and stronger associations with NAP and ANT. Ecological risk assessment using hazard quotients (HQ_water) indicated negligible acute toxicity risk across all sites and seasons (<0.01); the highest HQ_water (0.0095), observed upstream during the wet season, remained within this range. However, benchmark exceedances by PHEN and ANT suggest potential chronic risks not captured by the acute ERA framework. These findings support integrated watershed management practices to mitigate PAH pollution and strengthen long-term ecological health in tropical urban wetlands. Full article

Microcystin–LR (MC-LR) and phenanthrene (Phen), which commonly co-occur in eutrophic waters, have been extensively studied as individual contaminants, but their combined ecotoxicological effects on submerged macrophytes remain unclear. In this study, we examined the individual and combined toxicity of MC-LR (2, 10, 50, 250, and 1000 μg/L) and Phen (0.2, 1, 5, 25, and 100 μg/L) on the submerged macrophyte Vallisneria natans over a 7-day exposure. Key toxicity biomarkers, including growth, photosynthetic efficiency, and antioxidant responses (catalase, superoxide dismutase, glutathione S-transferase, and malondialdehyde), were evaluated. The results showed that high concentrations of each contaminant alone (MC-LR ≥ 1000 μg/L; Phen ≥ 100 μg/L) significantly inhibited growth and reduced photosynthetic efficiency. In contrast, synergistic toxicity was observed at much lower combined concentrations (≥50 + 5 μg/L), with effects substantially exceeding those of individual exposures. Co-exposure intensified antioxidant activity, but it was insufficient to mitigate oxidative damage. Notably, Phen at concentrations above 25 μg/L significantly enhanced the bioaccumulation of MC-LR in V. natans. These findings demonstrate that environmentally relevant mixtures of MC-LR and Phen induce remarkable toxicity even at concentrations where individual compounds show negligible effects. The results highlight that co-existing cyanotoxins and polycyclic aromatic hydrocarbons may present greater ecological risks than predicted from single-contaminant assessments, underscoring the need to update current ecological risk frameworks for the accurate evaluation of complex pollution scenarios in freshwater systems. Full article

Co-contamination of cadmium (Cd) and polycyclic aromatic hydrocarbons (PAHs) in agricultural soils poses a critical threat to crops and food safety, but how PAHs affect Cd uptake and plant metabolism is still unclear. Maize (Zea mays L.) of the variety Hanyu 702 (HY702) was previously identified by our group asaccumulating Cd at low levels when grown in soil containing Cd and phenanthrene (Phe). These contaminants were used here as model pollutions, alone and in combination, to assess the accumulation, growth, physiological, and metabolic responses of HY702 seedlings. Four treatments were compared, including a control without pollution, single Phe pollution, single Cd pollution, and Cd and Phe combined pollution. The experiments followed a completely randomized design with three replicates per treatment. The results revealed that Cd accumulation in the plants was significantly reduced when Phe was present as well (9% reduction in roots and 44% in stems and leaves compared to Cd single pollution). The combined Cd-Phe pollution had no significant impact on the height or chlorophyll content of the maize plants but markedly reduced their malondialdehyde (MDA) content. In addition, it increased the proline content by 56% and antioxidant enzyme activity by 15% (peroxidase, POD), 24% (superoxide dismutase, SOD), and 57% (catalase, CAT) compared to the control treatment. Metabolomics analysis revealed that the coexistence of Phe and Cd activated four key metabolic pathways: (a) alanine, aspartate, and glutamate metabolism; (b) valine, leucine, and isoleucine biosynthesis; (c) aminoacyl-tRNA biosynthesis; and (d) histidine metabolism. This activation resulted in increased levels of six differential metabolites: L-asparagine, L-methionine, L-glutamate, (S)-2-acetyl-2-hydroxybutanoic acid, urocanic acid, and 2-isopropylmalic acid. These metabolites induced detoxification pathways and reduced Cd accumulation. The findings reported here offer new insights into how plants metabolically adapt to the combined pollution of Cd and PAHs and provide an important scientific basis for pollution control strategies. Full article

The anthrone-based dummy molecularly imprinted membrane (DIM) was successfully synthesized using a semi-interpenetrating polymer network (semi-IPN) approach for the selective recognition and adsorption of fluorene and phenanthrene in aqueous systems. Fourier-transform infrared spectroscopy (FTIR) confirmed the successful incorporation of functional groups, while scanning electron microscopy (SEM) revealed a uniform porous morphology favorable for analyte diffusion. Thermogravimetric analysis (TGA) demonstrated good thermal stability, and Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses indicated an enhanced surface area and mesoporous structure that supported improved adsorption performance. Adsorption isotherm studies revealed favorable adsorption behavior, with the maximum adsorption capacities of the DIM calculated to be 130.857 mg/g for fluorene and 453.030 mg/g for phenanthrene. The imprinting factors (IFs) were approximately 2.01 for fluorene and 2.17 for phenanthrene, confirming the successful imprinting effect. The recovery values achieved were 86.61% for fluorene and 92.40% for phenanthrene, demonstrating the efficiency and selectivity of the fabricated membrane. These results highlight the potential application of the anthrone-based DIM in the environmental monitoring of polycyclic aromatic hydrocarbons (PAHs). Full article