Distribution and bioaccumulation status of polycyclic aromatic hydrocarbons (PAHs) in Veraval coastal waters using copepods as bio-indicators.

The study investigates the pollution characteristics of 16 priority PAHs, accumulated in copepods from a major fishing harbour and its adjacent coastal waters of Veraval, west coast of India. The total PAH accumulation is in the range of 922.16-27,807.49 ng g-1 dw, with the mean concentration of 5776.59 ng g-1 dw. High concentrations of PAHs were present in the copepod samples from inside the harbour. Notably, there was no significant correlation between the lipid content of copepods and the accumulation of PAHs. The molecular diagnostic ratio method (MDR) indicates that the PAH sources are petrogenic in origin, while principal component analysis (PCA) points to petroleum, coal combustion and vehicular emission sources. Total cancerous PAHs (C-PAHs) in the study area dominate by 40% of the total PAHs identified; moreover, the bioaccumulation factor (BAF) is very high in the offshore area, which is also a fishing ground. The global relevance and magnitude of the present study in the Veraval, one of the prime seafood exporting hubs in India, should be dealt with utmost avidity as the accumulation status of PAHs in the zooplankton has never been explored in the Indian coastal waters. Moreover, the current study gives the foremost data on the bioaccumulation status of PAHs in copepods from the tropical waters of India.

Pseudomonas aeruginosa PR23 isolated from oil contaminated soil tolerate and degrades mixture of polyaromatic hydrocarbons and express novel proteins.

Pseudomonas aeruginosa PR23 isolated from the hydrocarbon contaminated soil can tolerate and degrade mixture of polyaromatic hydrocarbons (PAHs) at an initial concentration of 1300 ppm. The degradation and intermediates formed were assessed by gas chromatography-mass spectrometry (GC-MS) analysis. The isolated strain was able to degrade 59.2% of the mixture of PAHs in 3 days and 71.6% by day 15. Effect of PAHs on protein expression in Pseudomonas aeruginosa PR23 was studied using nano LC-MS/MS. Thirty-six proteins showed a more than 2-fold increase in expression in the presence of mixture of PAHs. Out of these proteins, 7 proteins have been reported for their role in degradation of naphthalene, phenanthrene, and pyrene. The data revealed the presence of 16 proteins that were uniquely expressed in the presence of mixture of PAHs. A twin-arginine translocation signal peptide (Tat system), known for the transportation of folded proteins across the cell membrane, showed more than 8-fold increased expression in the presence of mixture of PAHs. These results indicate that the isolated strain adopts the conditions in the presence of mixture of PAHs by modulating its metabolic and physiological processes. These findings suggest that Pseudomonas aeruginosa PR23 may be a suitable candidate for use in the development of strategies for bioremediation of mixtures of PAHs.

Key role of plankton species and nutrients on biomagnification of PAHs in the micro-food chain: A case study in plateau reservoirs of Guizhou, China.

There is considerable inconsistency in results pertaining to the biomagnification of PAHs in aquatic systems. Zooplankton specifically play an important role controlling the fate and distribution of organic contaminants up the food chain, particularly in large plateau reservoirs. However, it remains largely unknown how secondary factors affect the magnification of organic compounds in zooplankton. The present study assessed plankton species and nutrients affecting the trophic transfer of PAHs through the micro-food chain in plateau reservoirs, Guizhou Province China. Results show soluble ∑PAHs range from 99.9 - 147.3 ng L-1, and concentrations of ∑PAHs in zooplankton range from 1003.2 - 22441.3, with a mean of 4460.7 ng g-1 dw. Trophic magnification factors (TMFs) > 1 show biomagnifications of PAHs from phytoplankton to zooplankton. The main mechanisms for trophic magnification > 1 are 1) small Copepoda, Cladocera and Rotifera are prey for larger N. schmackeri and P. tunguidus, and 2) the δ15N and TLs of zooplankton are increasing with the increasing nutrients TN, NO3- and CODMn. As a result, log PAHs concentrations in zooplankton are positively correlated with the trophic levels (TLs) of zooplankton, and log BAFs of the PAHs in zooplankton are increasing with increasing TLs and log Kow. Temperature further enhances TMFs and biomagnifications of PAHs as noted by temperature related reductions in δ15N. There are also available soluble PAHs in the water column which are assimilated with increasing phytoplankton biomass within the taxa groups, diatoms, dinoflagellates and chlorophytes. Notable TMFs of PAHs in zooplankton in Guizhou plateau reservoirs are not significantly affected by phytoplankton and zooplankton biomass dilutions. The present study demonstrates the important roles of species selection, nutrients and temperature in the environmental fate of PAHs in freshwaters.

Sphingobium sp. SJ10-10 encodes a not-yet-reported chromate reductase and the classical Rieske dioxygenases to simultaneously degrade PAH and reduce chromate.

Both polycyclic aromatic hydrocarbons (PAHs) and heavy metals persist in the environment and are toxic to organisms. Their co-occurrence makes any of them difficult to remove during bioremediation and poses challenges to environmental management and public health. Microorganisms capable of effectively degrading PAHs and detoxifying heavy metals concurrently are required to improve the bioremediation process. In this study, we isolated a new strain, Sphingobium sp. SJ10-10, from an abandoned coking plant and demonstrated its capability to simultaneously degrade 92.6 % of 75 mg/L phenanthrene and reduce 90 % of 3.5 mg/L hexavalent chromium [Cr(VI)] within 1.5 days. Strain SJ10-10 encodes Rieske non-heme iron ring-hydroxylating oxygenases (RHOs) to initiate PAH degradation. Additionally, a not-yet-reported protein referred to as Sphingobium chromate reductase (SchR), with low sequence identity to known chromate reductases, was identified to reduce Cr(VI). SchR is distributed across different genera and can be classified into two classes: one from Sphingobium members and the other from non-Sphingobium species. The widespread presence of SchR in those RHO-containing Sphingobium members suggests that they are excellent candidates for bioremediation. In summary, our study demonstrates the simultaneous removal of PAHs and Cr(VI) by strain SJ10-10 and provides valuable insights into microbial strategies for managing complex pollutant mixtures.

Polycyclic aromatic hydrocarbon: underpinning the contribution of specialist microbial species to contaminant mitigation in the soil.

The persistence of PAHs poses a significant challenge for conventional remediation approaches, necessitating the exploration of alternative, sustainable strategies for their mitigation. This review underscores the vital role of specialized microbial species (nitrogen-fixing, phosphate-solubilizing, and biosurfactant-producing bacteria) in tackling the environmental impact of polycyclic aromatic hydrocarbons (PAHs). These resistant compounds demand innovative remediation strategies. The study explores microbial metabolic capabilities for converting complex PAHs into less harmful byproducts, ensuring sustainable mitigation. Synthesizing literature from 2016 to 2023, it covers PAH characteristics, sources, and associated risks. Degradation mechanisms by bacteria and fungi, key species, and enzymatic processes are examined. Nitrogen-fixing and phosphate-solubilizing bacteria contributions in symbiotic relationships with plants are highlighted. Biosurfactant-producing bacteria enhance PAH solubility, expanding microbial accessibility for degradation. Cutting-edge trends in omics technologies, synthetic biology, genetic engineering, and nano-remediation offer promising avenues. Recommendations emphasize genetic regulation, field-scale studies, sustainability assessments, interdisciplinary collaboration, and knowledge dissemination. These insights pave the way for innovative, sustainable PAH-contaminated environment restoration.

Structure-based modeling to assess binding and endocrine disrupting potential of polycyclic aromatic hydrocarbons in Daniorerio.

Environmental contaminants, such as polycyclic aromatic hydrocarbons (PAHs), have raised concerns regarding their potential endocrine-disrupting effects on aquatic organisms, including fish. In this study, molecular docking and molecular dynamics techniques were employed to evaluate the endocrine-disrupting potential of PAHs in zebrafish, as a model organism. A virtual screening with 72 PAHs revealed a correlation between the number of PAH aromatic rings and their binding affinity to proteins involved in endocrine regulation. Furthermore, PAHs with the highest binding affinities for each protein were identified: cyclopenta[cd]pyrene for AR (-9.7 kcal/mol), benzo(g)chrysene for ERα (-11.5 kcal/mol), dibenzo(a,e)pyrene for SHBG (-8.7 kcal/mol), dibenz(a,h)anthracene for StAR (-11.2 kcal/mol), and 2,3-benzofluorene for TRα (-9.8 kcal/mol). Molecular dynamics simulations confirmed the stability of the protein-ligand complexes formed by the PAHs with the highest binding affinities throughout the simulations. Additionally, the effectiveness of the protocol used in this study was demonstrated by the receiver operating characteristic curve (ROC) analysis, which effectively distinguished decoys from true ligands. Therefore, this research provides valuable insights into the endocrine-disrupting potential of PAHs in fish, highlighting the importance of assessing their impact on aquatic ecosystems.

Changes in the Non-targeted Metabolomic Profile of Three-year-old Toddlers with Elevated Exposure to Polycyclic Aromatic Hydrocarbons.

Objective: To investigate changes in the urinary metabolite profiles of children exposed to polycyclic aromatic hydrocarbons (PAHs) during critical brain development and explore their potential link with the intestinal microbiota. Methods: Liquid chromatography-tandem mass spectrometry was used to determine ten hydroxyl metabolites of PAHs (OH-PAHs) in 36-month-old children. Subsequently, 37 children were categorized into low- and high-exposure groups based on the sum of the ten OH-PAHs. Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to identify non-targeted metabolites in the urine samples. Furthermore, fecal flora abundance was assessed by 16S rRNA gene sequencing using Illumina MiSeq. Results: The concentrations of 21 metabolites were significantly higher in the high exposure group than in the low exposure group (variable importance for projection > 1, P < 0.05). Most of these metabolites were positively correlated with the hydroxyl metabolites of naphthalene, fluorine, and phenanthrene ( r = 0.336-0.531). The identified differential metabolites primarily belonged to pathways associated with inflammation or proinflammatory states, including amino acid, lipid, and nucleotide metabolism. Additionally, these distinct metabolites were significantly associated with specific intestinal flora abundances ( r = 0.34-0.55), which were mainly involved in neurodevelopment. Conclusion: Higher PAH exposure in young children affected metabolic homeostasis, particularly that of certain gut microbiota-derived metabolites. Further investigation is needed to explore the potential influence of PAHs on the gut microbiota and their possible association with neurodevelopmental outcomes.

Biodegradation of high molecular weight polycyclic aromatic hydrocarbons by Sarocladium terricola strain PYR-233 isolated from petrochemical contaminated sediment.

Polycyclic aromatic hydrocarbons (PAHs) were frequently found in sediment and were primarily treated through microbial degradation. Thus, efficient management of PAH pollution requires exploring the molecular degradation mechanisms of PAHs and expanding the pool of available microbial resources. A fungus (identified as Sarocladium terricola strain RCEF778) with the remarkable ability to degrade pyrene was screened from sediment near a petrochemical plant, and its growth and pyrene degradation characteristics were comprehensively investigated. The results showed that the fungus exhibited great effectiveness in pyrene degradation, with a degradation ratio of 88.97% at 21 days at the conditions: 35 °C, pH 7, 10 mg L-1 initially pyrene concentration, 3% supplementary salt, and glucose supplementation. The generation and concentration variation of the intermediate products were identified, and the results revealed that the fungus degraded pyrene through two pathways: by salicylic acid and by phthalic acid. Three sediments (M1, M2, M3), each exhibiting different levels of PAH pollution, were employed to examine the effectiveness of fungal degradation of PAHs in practical sediment samples. These data showed that with the fungus, the degradation ratios ranged from 13.64% to 23.50% for 2-3 rings PAHs, 40.93%-49.41% for 4 rings PAHs, and 39.59%-48.07% for 5-6 rings PAHs, which were significantly higher than those for the sediment without the fungus and confirmed the excellent performance of the fungal. Moreover, the Gompertz model was employed to analyze the degradation kinetics of 4-rings and 5-6 rings PAHs in these sediments, and the results demonstrated that the addition of the fungus could significantly increase the maximum degradation ratio, degradation start-up rate and maximum degradation rate of 4-rings and 5-6 rings PAHs and shorten the time required to reach the maximum degradation rate. This study not only supplied fungal materials but also established crucial theoretical foundations for the development of bioremediation technologies aimed at high molecular weight PAH-contaminated sediments.

Evaluating the Kinetics and Molecular Mechanism for Biomimetic Metabolic Activation of PAHs by Surface-Enhanced Raman Scattering Spectroscopy.

Biomimetic cytochrome P450 for chemical activation of environmental carcinogens is an efficient in vitro model for evaluating their mutagenicity and ultimately acquiring the metabolites that cannot be easily accessed by conventional routes of organic synthesis. Different kinds of mutagen derived from polyaromatic hydrocarbons (PAHs) by metalloporphyrin/oxidant model systems have been reported, but the underlying molecular mechanisms are poorly understood. Herein, we have for the first time demonstrated an effective surface-enhanced Raman scattering (SERS) protocol to study the dynamics and biomimetic metabolic behaviors of pyrene (Pyr) in the presence of various oxygen donors. Quantitative information on the relative concentration of Pyr and its metabolites in the biomimetic system can be extracted from the SERS spectra. On the basis of our results, we conclude that the oxidative metabolism of Pyr is highly influenced by the types and concentrations of oxygen donors, leading to the formation of 1-hydroxypyrene and dioxygenated products. Besides, the addition of an appropriate amount of an organic solvent can promote the formation of secondary oxidation products. These results offer valuable insights into the dynamics of PAHs metabolism and the regulation of their metabolic pathways in biomimetic activation. In comparison to traditional liquid chromatography-mass spectrometry, the present SERS approach is more suitable for high-throughput evaluation of the metabolic process and kinetics of PAHs. We anticipate that this approach will enable a more general and comprehensive tracking of metabolic dynamics and molecular mechanisms involved in the biomimetic activation of other xenobiotics, such as procarcinogens, promutagens, and drugs.

A combination of microbial electrolysis cells and bioaugmentation can effectively treat synthetic wastewater containing polycyclic aromatic hydrocarbon.

The anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) is challenging due to its toxic effect on the microbes. Microbial electrolysis cells (MECs), with their excellent characteristics of anodic and cathodic biofilms, can be a viable way to enhance the biodegradation of PAHs. This work assessed different cathode materials (carbon brush and nickel foam) combined with bioaugmentation on typical PAHs-naphthalene biodegradation and analyzed the inhibition amendment mechanism of microbial biofilms in MECs. Compared with the control, the degradation efficiency of naphthalene with the nickel foam cathode supplied with bioaugmentation dosage realized a maximum removal rate of 94.5 ± 3.2%. The highest daily recovered methane yield (227 ± 2 mL/gCOD) was also found in the nickel foam cathode supplied with bioaugmentation. Moreover, the microbial analysis demonstrated the significant switch of predominant PAH-degrading microorganisms from Pseudomonas in control to norank_f_Prolixibacteraceae in MECs. Furthermore, hydrogentrophic methanogenesis prevailed in MEC reactors, which is responsible for methane production. This study proved that MEC combined with bioaugmentation could effectively alleviate the inhibition of PAH, with the nickel foam cathode obtaining the fastest recovery rate in terms of methane yield.

Physiology and comparative genomics of the haloalkalitolerant and hydrocarbonoclastic marine strain Rhodococcus ruber MSA14.

Marine hydrocarbonoclastic bacteria can use polycyclic aromatic hydrocarbons as carbon and energy sources, that makes these bacteria highly attractive for bioremediation in oil-polluted waters. However, genomic and metabolic differences between species are still the subject of study to understand the evolution and strategies to degrade PAHs. This study presents Rhodococcus ruber MSA14, an isolated bacterium from marine sediments in Baja California, Mexico, which exhibits adaptability to saline environments, a high level of intrinsic pyrene tolerance (> 5 g L- 1), and efficient degradation of pyrene (0.2 g L- 1) by 30% in 27 days. Additionally, this strain demonstrates versatility by using naphthalene and phenanthrene as individual carbon sources. The genome sequencing of R. ruber MSA14 revealed a genome spanning 5.45 Mbp, a plasmid of 72 kbp, and three putative megaplasmids, lengths between 110 and 470 Kbp. The bioinformatics analysis of the R. ruber MSA14 genome revealed 56 genes that encode enzymes involved in the peripheral and central pathways of aromatic hydrocarbon catabolism, alkane, alkene, and polymer degradation. Within its genome, R. ruber MSA14 possesses genes responsible for salt tolerance and siderophore production. In addition, the genomic analysis of R. ruber MSA14 against 13 reference genomes revealed that all compared strains have at least one gene involved in the alkanes and catechol degradation pathway. Overall, physiological assays and genomic analysis suggest that R. ruber MSA14 is a new haloalkalitolerant and hydrocarbonoclastic strain toward a wide range of hydrocarbons, making it a promising candidate for in-depth characterization studies and bioremediation processes as part of a synthetic microbial consortium, as well as having a better understanding of the catabolic potential and functional diversity among the Rhodococci group.

Fine-tuning an aromatic ring-hydroxylating oxygenase to degrade high molecular weight polycyclic aromatic hydrocarbon.

Rieske nonheme iron aromatic ring-hydroxylating oxygenases (RHOs) play pivotal roles in determining the substrate preferences of polycyclic aromatic hydrocarbon (PAH) degraders. However, their potential to degrade high molecular weight PAHs (HMW-PAHs) has been relatively unexplored. NarA2B2 is an RHO derived from a thermophilic Hydrogenibacillus sp. strain N12. In this study, we have identified four "hotspot" residues (V236, Y300, W316, and L375) that may hinder the catalytic capacity of NarA2B2 when it comes to HMW-PAHs. By employing structure-guided rational enzyme engineering, we successfully modified NarA2B2, resulting in NarA2B2 variants capable of catalyzing the degradation of six different types of HMW-PAHs, including pyrene, fluoranthene, chrysene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[a]pyrene. Three representative variants, NarA2B2W316I, NarA2B2Y300F-W316I, and NarA2B2V236A-W316I-L375F, not only maintain their abilities to degrade low-molecular-weight PAHs (LMW-PAHs) but also exhibited 2 to 4 times higher degradation efficiency for HMW-PAHs in comparison to another isozyme, NarAaAb. Computational analysis of the NarA2B2 variants predicts that these modifications alter the size and hydrophobicity of the active site pocket making it more suitable for HMW-PAHs. These findings provide a comprehensive understanding of the relationship between three-dimensional structure and functionality, thereby opening up possibilities for designing improved RHOs that can be more effectively used in the bioremediation of PAHs.

Occurrence and dissipation mechanisms of organic contaminants during sewage sludge anaerobic digestion: A critical review.

Sewage sludge, a complex mixture of contaminants and pathogenic agents, necessitates treatment or stabilization like anaerobic digestion (AD) before safe disposal. AD-derived products (solid digestate and liquid fraction) can be used as fertilizers. During AD, biogas is also produced, and used for energy purposes. All these fractions can be contaminated with various compounds, whose amount depends on the feedstocks used in AD (and their mutual proportions). This paper reviews studies on the distribution of organic contaminants across AD fractions (solid digestate, liquid fraction, and biogas), delving into the mechanisms behind contaminant dissipation and proposing future research directions. AD proves to be a relatively effective method for removing polychlorinated biphenyls, polycyclic aromatic hydrocarbons, pharmaceuticals, antibiotic resistance genes and hydrocarbons. Contaminants are predominantly removed through biodegradation, but many compounds, especially hydrophobic (e.g. per- and polyfluoroalkyl substances), are also sorbed onto digestate particles. The process of sorption is suggested to reduce the bioavailability of contaminants. As a result of sorption, contaminants accumulate in the largest amount in the solid digestate, whereas in smaller amounts in the other AD products. Polar pharmaceuticals (e.g. metformin) are particularly leached, while volatile methylsiloxanes and polycyclic aromatic hydrocarbons, characterized by a high Henry's law constant, are volatilized into the biogas. The removal of compounds can be affected by AD operational parameters, the type of sludge, physicochemical properties of contaminants, and the sludge pretreatment used.

Accumulation of Atmospheric PAHs in White Mustard - Can the Seeds Be Affected?

Traffic-related particulate matter emissions have been considerably reduced due to stringent regulations in Europe. However, emission of diesel-powered vehicles still poses a significant environmental threat, affecting rural ecosystems and agriculture. Several studies have reported that polycyclic aromatic hydrocarbons (PAHs), a group of potentially toxic organic compounds, can accumulate in crops and vegetables. In our study, white mustard (Sinapis alba L.) plants were experimentally treated with an extract of diesel exhaust. PAH concentrations were measured in the different plant compartments (stems, leaves and seeds), bioconcentration factors (BCFs) were also calculated. Significant accumulation was measured in the leaves and seeds, stems showed lower accumulation potential. All plant matrices showed high tendency to accumulate higher molecular weight PAHs, BCF was the highest in the 6-ring group. The fact that considerable accumulation was experienced in the seeds might show the risk of cultivating crops nearby roads highly impacted by traffic-related emissions.

Multispecies and multibiomarker assessment of fish health from Iguaçu River reservoir, Southern Brazil.

This study investigated the impact of micropollutants on fish health from Segredo hydroelectric reservoir (HRS) along the Iguaçu River, Southern Brazil, contaminated by urban, industrial, and agricultural activities. This is the first comprehensive study assessment in the river after the severe drought in the 2020s in three fish species from different trophic levels Astyanax spp. (water column depth/omnivorous), Hypostomus commersoni (demersal/herbivorous), and Pimelodus maculatus (demersal/omnivorous). Animals, water, and sediment samples were collected from three distinct sites within the reservoir: Floresta (upstream), Iratim (middle), and Station (downstream). The chemical analysis revealed elevated concentrations of metals (Al, Cu, Fe) and the metalloid As in water, or Cu, Zn, and As in sediment, surpassing Brazilian regulatory limits, while the organic pollutants as DDT, PAHs, PCBs, and PBDEs were found under the Brazilian regulatory limits. The metal bioaccumulation was higher in gills with no significant differences among sites. The species Astyanax spp. and H. commersoni displayed variations in hepatosomatic index (HSI) and P. maculatus in the condition factor index (K) between sites, while adverse effects due to micropollutants bioaccumulation were observed by biochemical, genotoxic, and histopathological biomarkers. The principal component analysis and integrated biomarker response highlighted the upstream site Floresta as particularly inhospitable for biota, with distinctions based on trophic level. Consequently, this multifaceted approach, encompassing both fish biomarkers and chemical analyses, furnishes valuable insights into the potential toxic repercussions of micropollutant exposure. These findings offer crucial data for guiding management and conservation endeavors in the Iguaçu River.

Polycyclic aromatic hydrocarbon skin permeation efficiency in vitro is lower through human than pigskin and decreases with lipophilicity.

Polycyclic aromatic hydrocarbons (PAH) are persistent environmental pollutants, which occasionally appear as contaminants in consumer products. Upon dermal contact, transfer of PAH into the stratum corneum (s.c.) and migration through the skin may occur, resulting in this class of highly toxic compounds to become bioavailable. In this study, dermal penetration through human and porcine skin of 24 PAH, comprising broad molar mass (M: 152-302 g/mol) and octanol-water partition coefficient (logP: 3.9-7.3) ranges, was evaluated via Franz diffusion cell in vitro assays. More lipophilic and potentially more toxic PAH had decreased permeation rates through the rather lipophilic s.c. into the more hydrophilic viable (epi-)dermis. Furthermore, human skin was less permeable than pigskin, a commonly used surrogate in skin penetration studies. In particular, the s.c. of human skin retains a greater share of PAH, an effect that is more pronounced for smaller PAH. Additionally, we compared the skin permeation kinetics of different PAH in pigskin. While small PAH (M < 230 g/mol, logP < 6) permeate the skin quickly and are detected in the receptor fluid after 2 h, large PAH (M > 252 g/mol, logP ≥ 6) do not fully permeate the skin up to 48 h. This indicates that highly lipophilic PAH do not become bioavailable as readily as their smaller congeners when transferred to the skin surface. Our data suggest that pigskin could be used as a surrogate for worst case scenario estimates of dermal PAH permeation through human skin.

Mechanism of cytochrome P450s mediated interference with glutathione and amino acid metabolisms from halogenated PAHs exposure.

Epidemiological evidence indicates that exposure to halogenated polycyclic aromatic hydrocarbons (HPAHs) is associated with many adverse effects. However, the mechanisms of metabolic disorder of HPAHs remains limited. Herein, effects of pyrene (Pyr), and its halogenated derivatives (1-chloropyrene (1-Cl-Pyr), 1-bromopyrene (1-Br-Pyr)) on endogenous metabolic pathways were investigated, in human hepatoma (HepG2) and HepG2-derived cell lines expressing various human cytochrome P450s (CYPs). Non-targeted metabolomics results suggested that 1-Br-Pyr and Pyr exposure (625 nM) induced disruption in glutathione and riboflavin metabolism which associated with redox imbalance, through abnormal accumulation of oxidized glutathione, mediated by bioactivation of CYP2E1. Conversely, CYP2C9-mediated 1-Cl-Pyr significantly interfered with glutathione metabolism intermediates, including glycine, L-glutamic acid and pyroglutamic acid. Notably, CYP1A1-mediated Pyr-induced perturbation of amino acid metabolism which associated with nutrition and glycolipid metabolism, resulting in significant upregulation of most amino acids, whereas halogenated derivatives mediated by CYP1A2 substantially downregulated amino acids. In conclusion, this study suggested that Pyr and its halogenated derivatives exert potent effects on endogenous metabolism disruption under the action of various exogenous metabolic enzymes (CYPs). Thus, new evidence was provided to toxicological mechanisms of HPAHs, and reveals potential health risks of HPAHs in inducing diseases caused by redox and amino acid imbalances.

Bioaccumulation of polycyclic aromatic hydrocarbons and their human health risks depend on the characteristics of microplastics in marine organisms of Sanggou Bay, China.

Microplastics pose a threat to marine environments through their physical presence and as vectors of chemical pollutants. However, the impact of microplastics on the accumulation and human health risk of chemical pollutants in marine organisms remains largely unknown. In this study, we investigated the microplastics and polycyclic aromatic hydrocarbons (PAHs) pollution in marine organisms from Sanggou Bay and analyzed their correlations. Results showed that microplastic and PAHs concentration ranged from 1.23 ± 0.23 to 5.77 ± 1.10 items/g, from 6.98 ± 0.45 to 15.07 ± 1.25 µg/kg, respectively. The microplastic abundance, particularly of fibers, transparent and color plastic debris, correlates strongly with PAH contents, indicating that microplastics increase the bioaccumulation of PAHs and microplastics with these characteristics have a significant vector effect on PAHs. Although consuming seafood from Sanggou Bay induce no carcinogenic risk from PAHs, the presence of microplastics in organisms can significantly increases incremental lifetime cancer risk of PAHs. Thus, microplastics can serve as transport vectors for PAHs with implications for the potential health risks to human through consumption. This study provides new insight into the risks of microplastics in marine environments.

Phenanthrene metabolism in Panicum miliaceum: anatomical adaptations, degradation pathway, and computational analysis of a dioxygenase enzyme.

Polycyclic aromatic compounds (PAHs) are persistent organic pollutants of environmental concern due to their potential impacts on food chain, with plants being particularly vulnerable. While plants can uptake, transport, and transform PAHs, the precise mechanisms underlying their localization and degradation are not fully understood. Here, a cultivation experiment conducted with Panicum miliaceum exposed different concentrations of phenanthrene (PHE). Intermediate PHE degradation compounds were identified via GC-MS analysis, leading to the proposal of a phytodegradation pathway featuring three significant benzene ring cleavage steps. Our results showed that P. miliaceum exhibited the ability to effectively degrade high levels of PHE, resulting in the production of various intermediate products through several chemical changes. Examination of the localization and anatomical characteristics revealed structural alterations linked to PHE stress, with an observed enhancement in PHE accumulation density in both roots and shoots as treatment levels increased. Following a 2-week aging period, a decrease in the amount of PHE accumulation was observed, along with a change in its localization. Bioinformatics analysis of the P. miliaceum 2-oxoglutarate-dependent dioxygenase (2-ODD) DAO-like protein revealed a 299 amino acid structure with two highly conserved domains, namely 2OG-FeII_Oxy and DIOX_N. Molecular docking analysis aligned with experimental results, strongly affirming the potential link and direct action of 2-ODD DAO-like protein with PHE. Our study highlights P. miliaceum capacity for PAHs degradation and elucidates the mechanisms behind enhanced degradation efficiency. By integrating experimental evidence with bioinformatics analysis, we offer valuable insights into the potential applications of plant-based remediation strategies for PAHs-contaminated environments.

PAHs in franciscana dolphins from the Southwestern Atlantic Ocean: Concentration and maternal transfer assessments.

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds ubiquitous in the environment and known for their toxic, mutagenic, and carcinogenic effects. These compounds can bioaccumulate in the biota and be transferred through trophic webs. The franciscana dolphin (Pontoporia blainvillei), as top predators, can be an environmental sentinels. Thus, this study aimed to provide data about PAHs concentration in their hepatic tissue collected on the coast of Espírito Santo (Franciscana Management Area, FMA Ia), Rio de Janeiro (FMA IIa), and São Paulo states (FMA IIb), in Southeastern Brazil. PAHs were detected in 86 % of franciscana dolphins (n = 50). The highest ∑PAHsTotal median concentration was reported in FMA Ia followed by FMA IIb and FMA IIa (1055.6; 523.9, and 72.1 ng.g-1 lipid weight, respectively). Phenanthrene was detected in one fetus and two neonates, showing maternal transfer of PAHs in these dolphins. Evaluating PAHs with potential toxic effects is of utmost importance for the conservation of a threatened species.