Effects Of Polycyclic Aromatic Hydrocarbons Research Articles

Stress response and phytoextraction potential of two Noccaea caerulescens populations in multicontaminated soil

AbstractMulticontamination of soils by various organic and inorganic pollutants is considered as an obstacle for the development of hyperaccumulator plants and phytoextraction of metals. The aim of this study was to investigate the effect of polycyclic aromatic hydrocarbons (PAHs) in combination with trace elements on the antioxidant response and phytoextraction efficiency of two populations of the hyperaccumulator Noccaea caerulescens from either a metalliferous (Ganges) or a nonmetalliferous (Chavignée) site. Plants were grown for 17 days in soil containing moderate concentrations of trace elements and under the effect of phenanthrene (PHE), a PAH stress model. In general, exposure to PHE resulted in a reduction of growth parameters, together with the upregulation of antioxidant enzymes and compounds and limitations in nutrient uptake and heavy metal extraction in N. caerulescens. Variations were observed in the extent of enzymatic activities and the amount of metals extracted between the two populations studied. Plants from Chavignée exhibited a slightly more tolerant response to PHE stress than those from Ganges. The presence of PHE in the soil proved highly toxic to N. caerulescens, resulting in low numbers of survivors. Nevertheless, the differences observed between the two populations with regard to growth, metal extraction, and antioxidant defense responses suggest that the difference in defense capacity may ensure different tolerance. This difference may be linked to adaptations acquired by each population according to the soil type from which it originates. However, these results need to be confirmed by further experiments.

Prepubertal exposure to polycyclic aromatic hydrocarbons are associated with early pubertal development onset in boys: A longitudinal study

ObjectiveTo investigate the effects of polycyclic aromatic hydrocarbons(PAHs) on puberty in boys. Methods695 subjects were selected from four primary schools in Chongqing, China. 675 urine samples from these boys were collected four PAH metabolites: 1-hydroxypyrene, 2-hydroxynaphthoic, 2-hydroxyfluorene, and 9-hydroxyphenanthrene. Pubertal development of 695 boys was assessed at follow-up visits starting in December 2015 and occurring every six months thereafter until now, data used in this article ending in June 2021. A total of 12 follow-up visits were performed. Cox proportional hazards regression models were used to analyze the relationship between PAH metabolite concentrations and indicators of pubertal timing. ResultsThe mean age at puberty onset of testicular volume, facial hair, pubic hair, first ejaculation, and axillary hair in boys was 11.66, 12.43, 12.51, 12.72 and 13.70 years, respectively. Cox proportional hazards regression models showed that boys with moderate level of 1-OHPyr exposure was associated with earlier testicular development (hazard ratio [HR] = 1.276, 95% confidence interval [CI]: 1.006–1.619), with moderate level of 2-OHNap were at higher risk of early testicular development (HR = 1.273, 95% CI: 1.002–1.617) and early axillary hair development (HR = 1.355, 95% CI: 1.040–1.764), with moderate level of 2-OHFlu was associated with earlier pubic hair development (HR = 1.256, 95% CI: 1.001–1.577), with high level of 9-OHPhe were at higher risk of early fisrt ejaculation (HR = 1.333, 95% CI: 1.005–1.767) and early facial hair development (HR = 1.393, 95% CI: 1.059–1.831). ConclusionPrepubertal exposure to PAHs may be associated with earlier pubertal development in boys.

Toxic effects of polycyclic aromatic hydrocarbons on the two-sludge system: Combined functional gene, resistance gene and microbial community assessment

Polycyclic aromatic hydrocarbons (PAHs) were a class of persistent organic matter, and contained PAHs wastewater was discharged into wastewater treatment plants (WWTPs) finally, which could greatly affect their operational efficiency. The toxic effects of PAHs on the two-sludge system were assessed from functional genes, resistance genes, and microbial community. Three types of PAHs including Naphthalene (NAP), Anthracene (ANT), and Phenanthrene (PHE) were individually introduced into three separate two-sludge systems. Results showed that three types of PAHs did not adversely affect on nitrification performance, but exhibited a significant toxic effect on denitrification and phosphorus (PO43--P) removal. The effluent NH4+-N was almost 0 mg/L in all three systems, the highest total nitrogen (TN) removal rate was achieved at 90.88% in the PHE system, whereas the lowest rate was 72.46% in the ANT system. Concurrently, the PO43--P removal rate decreased from 93.10% to 51.22% in the ANT system. Functional genes, such as NORB and NIRS, and resistance genes such as PAH-RHD GNF/R and NAH-F/NH-R, were enriched in the PHE and NAP system, contributing to improved pollutant removal. However, the NIRK and PAH-RHD GPF/R were more abundant in the ANT system, resulting in varied pollutant removal capabilities. The composition of the microbial community was also influenced by PAH exposure with some specific functional bacteria being identified across the different systems. Among the PAHs tested, ANT was found to exert the highest toxicity towards the two-sludge system, surpassing the toxic effects of NAP and PHE. This study highlights the importance of considering PAH toxicity in the context of WWTPs operations and the potential need for tailored strategies to mitigate their impact on biological processes.

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

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

Environmental impact and human health effects of polycyclic aromatic hydrocarbons and remedial strategies: A detailed review

Polycyclic Aromatic Hydrocarbons (PAHs) profoundly impact public and environmental health. Gaining a comprehensive understanding of their intricate functions, exposure pathways, and potential health implications is imperative to implement remedial strategies and legislation effectively. This review seeks to explore PAH mobility, direct exposure pathways, and cutting-edge bioremediation technologies essential for combating the pervasive contamination of environments by PAHs, thereby expanding our foundational knowledge. PAHs, characterised by their toxicity and possession of two or more aromatic rings, exhibit diverse configurations. Their lipophilicity and remarkable persistence contribute to their widespread prevalence as hazardous environmental contaminants and byproducts. Primary sources of PAHs include contaminated food, water, and soil, which enter the human body through inhalation, ingestion, and dermal exposure. While short-term consequences encompass eye irritation, nausea, and vomiting, long-term exposure poses risks of kidney and liver damage, difficulty breathing, and asthma-like symptoms. Notably, cities with elevated PAH levels may witness exacerbation of bronchial asthma and chronic obstructive pulmonary disease (COPD). Bioremediation techniques utilising microorganisms emerge as a promising avenue to mitigate PAH-related health risks by facilitating the breakdown of these compounds in polluted environments. Furthermore, this review delves into the global concern of antimicrobial resistance associated with PAHs, highlighting its implications. The environmental effects and applications of genetically altered microbes in addressing this challenge warrant further exploration, emphasising the dynamic nature of ongoing research in this field.

Effects of Polycyclic Aromatic Hydrocarbons on the Composition of the Soil Bacterial Communities in the Tidal Flat Wetlands of the Yellow River Delta of China.

Polycyclic aromatic hydrocarbons (PAHs) are pervasive organic pollutants in coastal ecosystems, especially in tidal flat wetlands. However, the mechanisms through which PAHs impact the soil bacterial communities of wetlands featuring a simple vegetation structure in the Yellow River Delta (China) remain largely unclear. In this study, we examined soil samples from two sites featuring a single vegetation type (Suaeda salsa) in the Yellow River Delta. Specifically, we investigated the impacts of PAHs on the diversity and composition of soil bacteria communities through high-throughput 16 S rRNA sequencing. PAHs significantly increased the soil organic carbon content but decreased the total phosphorus content (p = 0.02). PAH contamination notably reduced soil bacterial community α diversity (Shannon index) and β diversity. Furthermore, PAHs significantly altered the relative abundance of bacterial phyla, classes, and genera (p < 0.05). Specifically, PAHs increased the relative abundance of the bacterial phyla Acidobacteriota and Gemmatimonadota (p < 0.05), while decreasing the relative abundance of Bacteroidota, Desulfobacterota, and Firmicutes compared to the control wetland (p < 0.05). Moreover, PAHs and certain soil properties [total nitrogen (TN), soil organic carbon (SOC), total phosphorus (TP), and total salt (TS)] were identified as key parameters affecting the community of soil bacteria, with the abundance of specific bacteria being both negatively and positively affected by PAHs, SOC, and TN. In summary, our findings could facilitate the identification of existing environmental problems and offer insights for improving the protection and management of tidal flat wetland ecosystems in the Yellow River Delta of China.

Relationships among protozoa, bacteria and fungi in polycyclic aromatic hydrocarbon-contaminated soils

Soil bacterial and fungal communities play key roles in the degradation of organic contaminants, and their structure and function are regulated by bottom-up and top-down factors. Microbial ecological effects of polycyclic aromatic hydrocarbons (PAHs) and trophic interactions among protozoa and bacteria/fungi in PAH-polluted soils have yet to be determined. We investigated the trophic interactions and structure of the microbiome in PAH-contaminated wasteland and farmland soils. The results indicated that the total concentration of the 16 PAHs (∑PAHs) was significantly correlated with the Shannon index, NMDS1 and the relative abundances of bacteria, fungi and protozoa (e.g., Pseudofungi) in the microbiome. Structural equation modelling and linear fitting demonstrated cascading relationships among PAHs, protozoan and bacterial/fungal communities in terms of abundance and diversity. Notably, individual PAHs were significantly correlated with microbe-grazing protozoa at the genus level, and the abundances of these organisms were significantly correlated with those of PAH-degrading bacteria and fungi. Bipartite networks and linear fitting indicated that protozoa indirectly modulate PAH degradation by regulating PAH-degrading bacterial and fungal communities. Therefore, protozoa might be involved in regulating the microbial degradation of PAHs by predation in contaminated soil.

Effects of Polycyclic Aromatic Hydrocarbons on Germination and Initial Growth of Selected Lawn Grass Species in Soil Polluted with PAHs

Effects of Polycyclic Aromatic Hydrocarbons on Germination and Initial Growth of Selected Lawn Grass Species in Soil Polluted with PAHs

Effect of Polycyclic Aromatic Hydrocarbons Extracted from Indoor Air of Coffee Shops on Oral Squamous Carcinoma Cell (KB/C152): An in Vitro Approach

Introduction: The two main causes of indoor air pollution (IAP) are cooking and smoking. Toxic substances, including polycyclic aromatic hydrocarbons (PAHs), recognized as human carcinogens, are present in cooking and tobacco smoke. This study aims to determine the cytotoxicity and genotoxicity of PAHs collected from the indoor air of coffee shops on human cell line (KB/C152) in vitro approach.&#x0D; Materials and methods: Sampling pumps at a 2 l/min flow rate for 5 hours were applied to collect indoor air samples. Next, KB cells in cell culture medium were exposed to different concentrations of extracted PAHs using Methyl Thiazolyl Tetrazolium (MTT) test. Finally, terminal dUTP nick-end labeling (TUNEL) test and cell cycle assessments were both examined using flow cytometry.&#x0D; Results: The MTT test revealed a significant cytotoxic effect on KB cells depending on the PAHs concentrationas compared to the control cell line. The lethal concentration 50 (LC50) value against KB cells was 100 ± 3.09 µg/ml. Accordingly, exposure to extracted PAHs resulted in an arrest in the cell cycle at the sub-G1 checkpoint. The extracted PAHs suppressed the cell cycle in the sub-G1 phase, damaged DNA, and arrested KB cells from proliferating. Additionally, a statistically significant increase in DNA cleavage percentages (p ≤ 0.05) was seen in the TUNEL test, which also showed a dose-dependent increase in DNA damage.&#x0D; Conclusion: Extracted PAHs caused DNA damage and arrested in the cell cycle in epidermoid carcinoma of the mouth cells (KB/C152) in vitro mechanisms. This evaluation highlights mechanisms of exposure to extracted PAHs and their detrimental health effects.

Physiological effects of polycyclic aromatic hydrocarbons (PAH) in fish organism

The pollution of world ocean is a serious threat to the biodiversity of flora and fauna. One of the most important sources of pollution are oil and oil products – every year more than 1 million tons of oil is spilled into the sea as a result of accidents during oil production or transportation. The teratogenic and carcinogenic effects of such oil components as benzopyrene is well known since the middle of the last century. However, after a large oil spill from “Exxon Valdez” tanker in 1989 it became clear that oil and its components have strong toxic effects in fish organism – and to a large extent these effects are caused by di- and tricyclic aromatic hydrocarbons, in particular phenanthrene. Field research have demonstrated that fish embryo and larvae are the most prone to the effects of oil – and the largest oil spills endanger the populations of important commercial fish species that spawn in this area. This review considers the influence of polycyclic aromatic hydrocarbons (PAH) on the physiology of various organ systems in fish. Particular attention is paid to the cardiotoxic effects of PAH which were recently discovered and which are potentially not only the main cause of animals’ death upon the spill of PAH into water, but also underlie the malformation of other organs.

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

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

Essential metals modified the effects of polycyclic aromatic hydrocarbons on the metabolic syndrome: Mediation effects of miRNA

Metabolic syndrome (MetS) prevalence has increased dramatically worldwide and has become a public health issue. Polycyclic aromatic hydrocarbons (PAHs) were identified as risk factors of MetS, while essential metals are integral parts of metalloenzymes catalyzing metabolic processes. However, effects of co-exposure to PAHs and essential metals have not been investigated yet. We aimed to assess whether essential metals could modify the hazard effects of PAHs on MetS, and underlying mediation effects of microRNA (miRNAs) were further explored. A cross-sectional study of 1451 males including 278 MetS cases was conducted. Internal exposure levels of 5 classes of PAH metabolites, 7 essential metals, as well as expressions of PAHs-associated 8 plasma miRNAs were assessed. Multiple exposure models, Bayesian kernel machine regression (BKMR), and quantile g-computation (QGcomp) were used simultaneously to identify MetS-related critical chemicals. Mutual effect modification between chemicals and mediation effects of miRNAs on chemical-MetS association was testified. In this study, hydroxyphenanthrene (OHPhe) and selenium (Se) were consistently identified as MetS-related key chemicals in three statistical methods. OHPhe was positively associated with MetS [OR (95 % CI) = 1.79 (1.21, 2.65), P = 0.004], while Se had a negative relationship with MetS [OR (95 % CI) = 0.61 (0.43, 0.87), P = 0.007]. Effect modification analysis observed the association between OHPhe and MetS was weakened with increased Se exposure. Only the expression of miR-24-3p was negatively associated with MetS [OR (95 % CI) = 0.81 (0.66, 0.95), P = 0.048] and could mediate 16.1 % of OHPhe-MetS association in subjects with low Se exposure (≤0.87 μg/mmol creatinine) (P = 0.019). We found a mutual effect modification between OHPhe and Se on MetS, and the positive OHPhe-MetS association was attenuated with increased Se exposure. Mediation effects of miR-24-3p on OHPhe-MetS association were dependent on Se dose. Our findings may provide new insight into the prevention and intervention of MetS.

Integrated metabolomics, transcriptomics, and proteomics analyses reveal co-exposure effects of polycyclic aromatic hydrocarbons and cadmium on ryegrass (Lolium perenne L.)

Cadmium (Cd) and polycyclic aromatic hydrocarbons (PAHs) are prominent soil contaminants found in industrial sites, and their combined effects on plants are not yet fully understood. To investigate the mechanisms underlying the co-exposure of Cd and PAHs and identify key biomarkers for their co-effects, an integrated analysis of metabolomics, transcriptomics, and proteomics was conducted on ryegrass leaves cultivated in soil. In nontarget metabolomics analysis, nine differentially expressed metabolites that were specifically induced by the compound exposure were identified. When combined with the analysis of differentially expressed genes and proteins, it was determined that the major pathways involved in the response to the co-stress of Cd and PAHs were linoleic acid metabolism and phenylpropanoid biosynthesis. The upregulation of 12,13-dihydroxy-9Z-octadecenoic acid and the downregulation of sinapyl alcohol were identified as typical biomarkers, respectively. Compared to scenarios of single exposures, the compound exposure to Cd and PAHs disrupted the oxidation of linoleic acid, leading to alterations in the profiles of linoleate metabolites. Additionally, it intensified hydroxylation, carboxylation, and methylation processes, and interfered with reactions involving coenzyme A, thus inhibiting lignin production. As a result, oxidative stress was elevated, and the cell wall defense system in ryegrass was weakened. The findings of this study highlight the ecological risks associated with unique biological responses in plants co-exposed to Cd and PAHs in polluted soils.

Investigation of the spatial distribution of airborne polycyclic aromatic hydrocarbons using Rhytidiadelphus squarrosus in Tórshavn, Faroe Islands.

Due to adverse effects of Polycyclic Aromatic Hydrocarbons (PAHs) on human health, it is important to understand how airborne PAHs, are spatially distributed within urban areas. Moss has been shown to be a suitable material for biomonitoring of airborne PAH pollution. In this study, the moss Rhytidiadelphus squarrosus was sampled throughout Tórshavn, Faroe Islands. 53 Rhytidiadelphus squarrosus samples were extracted using a matrix solid-phase dispersive extraction method and analysed for 19 parent PAHs and six groups of alkylated PAHs using gas chromatography mass-spectrometry. All PAHs were quantified in at least one Rhytidiadelphus squarrosus sample, and the sum of the EPA 16 PAHs (ƩPAHEPA16) ranged from 0.90 to 344µgkg-1 dry weight. Higher concentrations were found close to the harbour and the main roads. The spatial correlation was investigated for the ƩPAHEPA16, pyrene, fluoranthene, chrysene, benzo(e)pyrene, benzo(g,h,i)perylene, C1-phenanthrenes/C1-anthracenes, and C2-phenanthrenes/C2-anthracenes using variograms. The effective range of the spatial correlation was between 500 to 700m of all PAHs. The evaluation of diagnostic ratios of fluoranthene to pyrene, and benzo(a)anthracene to chrysene suggest that different pollution sources affect urban areas of different types. To the best of our knowledge, this is the first time airborne PAH pollution patterns were mapped in an Arctic town, and the first time, Rhytidiadelphus squarrosus was used for tracing PAH pollution sources. Rhytidiadelphus squarrosus is suitable for biomonitoring and mapping PAH pollution within urban areas since it is widespread, and suitable for mapping PAHs.

Association of polycyclic aromatic hydrocarbon internal exposure and urinary iodine concentration with thyroid volume in children

Thyroid volume was proposed as a factor for malignancy in evaluating thyroid nodules. Previous studies have demonstrated the endocrine disrupting effect of polycyclic aromatic hydrocarbons (PAHs), but studies on the association between internal exposure of PAHs and thyroid volume are still scarce. In this work, we evaluated the association of polycyclic aromatic hydrocarbon internal exposure and urinary iodine concentration with thyroid volume in 590 school-age children without thyroid disease in Guangzhou, China. Urinary hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), urinary iodine concentrations, and thyroid volumes were measured. The mean concentrations of urinary iodine and ΣOH-PAHs were 271.1 μg/L and 3.27 μg/L, respectively, and the mean thyroid volume was 2.4 mL. The associations of urinary iodine and OH-PAH concentrations with thyroid volume were investigated by multivariable linear regression and the Bayesian kernel machine regression models. Urinary ΣOH-PAHs were observed to be significantly positively associated with thyroid volume in multivariable linear regression models. The increase in each unit in the log-transformed concentration of ΣOH-PAHs caused 3.88% change in thyroid volume. The Bayesian kernel machine regression model demonstrated a positive joint effect of increased urinary ΣOH-PAHs on thyroid volume. Moreover, urinary ΣOH-PAHs were statistically significant linked to urinary iodine, and iodine mediated the relationship between urinary OH-PAHs and thyroid volume with the mediated proportions of 15.2%

Effect of polycyclic aromatic hydrocarbons on cancer risk causally mediated via vitamin D levels.

Polycyclic aromatic hydrocarbons (PAHs) widely exist in environmental substrates and are closely related to individual circulating vitamin D levels and tumorigenesis. Therefore, we proposed to evaluate the relationship between PAH exposure, vitamin D, and the risks for 14 cancer types via a causal inference framework underlying the mediation analysis. We evaluated seven urine monohydroxylated PAH (OH-PAH) and serum vitamin D concentrations of 3306 participants from the National Health and Nutrition Examination Survey between the 2013 and 2016 survey cycles and measured PAH concentrations in 150 subjects from the Nanjing cohort. We observed a significant negative dose-response relationship between increased OH-PAH levels and vitamin D deficiency. Each unit increase in ∑OH-PAHs could lead to a decrease in vitamin D levels (βadj = -0.98, Padj = 2.05 × 10-4 ). Body mass index could have interaction effects with ∑OH-PAHs and affect vitamin D levels. Coexposure to naphthalene and fluorene metabolites mutually affected vitamin D levels. Notably, vitamin D could causally mediate the relationship between OH-PAHs and nine types of cancer (e.g., colorectal cancer, liver cancers, etc.). This study first emphasizes the causal cascade of individual OH-PAHs, vitamin D, and cancer risk, providing insights into prevention via the environment.

Deep relationships between bacterial community and polycyclic aromatic hydrocarbons in soil profiles near typical coking plants.

Bacterial communities play an important role in maintaining the normal functioning of ecosystems; therefore, it is important to understand the effects of polycyclic aromatic hydrocarbons (PAHs) on the bacterial community. In addition, understanding the metabolic potential of bacterial communities for PAHs is important for the remediation of PAH-contaminated soils. However, the deep relationship between PAHs and bacterial community in coking plants is not clear. In this study, we determined the bacterial community and the concentration of PAHs in three soil profiles contaminated by coke plants in Xiaoyi Coking Park, Shanxi, China, using 16S rRNA and gas chromatography coupled with mass spectrometry, respectively. The results show that 2 ~ 3 rings PAHs are the main PAHs and Acidobacteria (23.76%) was the dominant bacterial community in three soil profiles. Statistical analysis showed that there were significant differences in the composition of bacterial communities at different depths and different sites. Redundancy analysis (RDA) and variance partitioning analysis (VPA) illustrate the influence of environmental factors (including PAHs, soil organic matter (SOM), and pH) on the vertical distribution of soil bacterial community, and PAHs were the main factors affecting the bacterial community in this study. The co-occurrence networks further indicated correlations between bacterial community and PAHs and found that Nap has the greatest effect on bacterial community compared with other PAHs. In addition, some operational taxonomic units (OTUs, OTU2, and OTU37) have the potential to degrade PAHs. PICRUSt2 (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) was used for further study on the potential of microbial PAHs degradation from a genetic perspective, which showed that different PAH metabolism genes were present in the genomes of bacterial communities in the three soil profiles, and a total of 12 PAH degradation-related genes were isolated, mainly dioxygenase and dehydrogenase genes.

Genotoxic effects of polycyclic aromatic hydrocarbons (PAHs) present in vehicle-wash wastewater on grass carp (Ctenopharyngodon idella) and freshwater mussels (Anodonta cygnea)

Vehicle-wash wastewater (VWW) contains high levels of various petrochemicals such as polycyclic aromatic hydrocarbons (PAHs), a carcinogenic category of organic substances. However, the genotoxic effects of PAHs present in VWW remain largely unknown. We explored the genotoxic effects of PAHs present in VWW on fish grass carp (Ctenopharyngodon idella) and freshwater mussels (Anodonta cygnea). Fish and freshwater mussels were divided into control and exposed groups, the prior groups were treated at weekly intervals with clean water, and the latter with Σ16PAHs contaminated VWW for up to four weeks. The samples of blood from fish and haemolymph from freshwater mussels were collected and analyzed using the comet assay technique. Results exhibited that in control fish and freshwater mussel groups the genotoxicity decreased with every week passing following the order of W1 > W2 > W3 > W4, ranging from 8.33 ± 3.06 to 25.3 ± 4.62 and from 46.0 ± 6.93 to 7.67 ± 3.79, respectively. The exposed fish and freshwater mussel groups indicated an increase in genotoxicity with increasing week intervals with an order of W4 > W3 > W2 > W1, ranging from 55.7 ± 11.9 to 128.3 ± 10.0 and from 112.7 ± 8.50 to 183.3 ± 10.1, respectively. The genotoxic effect of Σ16PAHs on fish was comparatively lower than on freshwater mussels. This study elucidates that VWW is highly genotoxic and should be treated before discharging into aquatic ecosystems.

Effects of particle-bound polycyclic aromatic hydrocarbons and plasticisers from different traffic sources on the human alveolar epithelial cell line A549

Road traffic represents a major source of particulate matter (PM), which is considered the most harmful pollutant for humans. This work aimed to evaluate the toxic effects of polycyclic aromatic hydrocarbons (PAHs) and plasticisers extracted from PM emitted by traffic, including exhaust samples, samples collected in a road tunnel and simultaneously in a nearby urban background atmosphere, and samples from the wear of distinct types of brakes. Different biological endpoints were investigated after exposing human alveolar epithelium A549 cells to the organic extracts: viability, cell cycle alterations and levels of intracellular reactive oxygen species (ROS). The particulate extracts from the wear of low steel brake pads induced greater decreases in cell viability. It was observed that cytotoxicity is more dependent on the individual composition of PAHs than on the global concentration. Exhaust samples from heavy-duty Euro V vehicles induced more toxic effects than Euro VI. Among Euro V vehicles, the exhaust of GTL was the most toxic. The composite weekly sample of the urban background atmosphere showed to be extremely toxic, decreasing cell viability to 2.66%, while the daily road tunnel samples caused a decrease of up to 83.6% at most. In the particulate extracts of the urban background atmosphere, retene and naphthalene were found, which were absent or present at trace levels in the tunnel. Irrespective of the sample, although some changes were observed in the A549 cell cycle after 24 h exposure in all the phases, the differences in the mean values were not great enough to exclude the possibility of random variability. When the results from the three phases (G0/G1, S and G2/M) of the cells exposed to all PM extracts were compared to the control, no statistically significant difference was detected. Regardless of the sample type, no significant increases in cellular ROS levels were observed either.

Effect of polycyclic aromatic hydrocarbons on homeobox gene expression during embryonic development of cuttlefish, Sepia officinalis

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants (POPs) commonly found in marine environments. Their bioaccumulation can cause harm to aquatic organisms, including invertebrates, particularly during the early stages of embryonic development. In this study, we evaluated, for the first time, the patterns of PAH accumulation in both capsule and embryo of common cuttlefish (Sepia officinalis). In addition, we explored the effects of PAHs by analysing the expression profiles of seven homeobox genes [i.e., gastrulation brain homeobox (GBX), paralogy group labial/Hox1 (HOX1), paralogy group Hox3 (HOX3), dorsal root ganglia homeobox (DRGX), visual system homeobox (VSX), aristaless-like homeobox (ARX) and LIM-homeodomain transcription factor (LHX3/4)]. We found that PAH levels in egg capsules were higher than those observed in chorion membranes (35.1 ± 13.3 ng/g vs 16.4 ± 5.9 ng/g). Furthermore, PAHs were also found in perivitellin fluid (11.5 ± 5.0 ng/ml). Naphthalene and acenaphthene were the congeners present at highest concentrations in each analysed egg component suggesting higher bioaccumulation rates. Embryos with high concentrations of PAHs also showed a significant increase in mRNA expression for each of the analysed homeobox genes. In particular, we observed a 15-fold increase in the ARX expression levels. Additionally, the statistically significant variation in homeobox gene expression patterns was accompanied by a concomitant increase in mRNA levels of both aryl hydrocarbon receptor (AhR) and estrogen receptor (ER). These findings suggest that bioaccumulation of PAHs may modulate developmental processes of cuttlefish embryos by targeting homeobox gene-mediated transcriptional outcomes. Mechanisms underlying the upregulation of homeobox genes could be related to the ability of PAHs to directly activate AhR- or ER-related signaling pathways.