Polycyclic aromatic hydrocarbon and its effects on human health: An overeview

Occurrence and spatiotemporal distribution of PAHs and OPAHs in urban agricultural soils from Guangzhou City, China

The occurrence of polycyclic aromatic hydrocarbon (PAH) derivatives in the environment is of growing concern because they exhibit higher toxicity than their parent PAHs. This study evaluated the large-scale occurrence and spatiotemporal distribution of 16 PAHs and 14 oxygenated PAHs (OPAHs) in urban agricultural soils from seven districts of Guangzhou City, China. Linear correlation analysis was conducted to explore the relationship between PAH and OPAH occurrence and a series of parameters. The compositional analysis, principal component analysis, diagnostic ratios, and principal component analysis coupled with a multiple linear regression model were used to identify the sources of PAHs and OPAHs in the soils. The average concentrations of ΣPAHs and ΣOPAHs (59.6 ± 31.1-213 ± 115.5 μg/kg) during the flood season were significantly higher than those during the dry season (42.1 ± 13.3-157.2 ± 98.2 μg/kg), which were due to relatively strong wet deposition during the flood season and weak secondary reactions during the dry season. Linear correlation analysis showed that soil properties, industrial activities, and agricultural activities (r = 0.27-0.96, p < 0.05) were responsible for the spatial distribution of PAHs during the dry season. The PAH distribution was mainly affected by precipitation during the flood season. The concentrations of ΣOPAHs were only related to the soil properties during the dry season because their occurrence was sensitive to secondary reactions, climate and meteorological conditions, and their water solubility. Our results further showed that coal combustion and traffic emissions were the dominant origins of PAHs and OPAHs during both the seasons. Wet deposition and runoff-induced transport also contributed to PAH and OPAH occurrence during the flood season. The results of this study can improve our understanding of the environmental risks posed by PAHs and OPAHs.

Novel insights into the predominant factors affecting the bioavailability of polycyclic aromatic hydrocarbons in industrial contaminated areas using PLS-developed model

Bioavailability is recognized as a useful technical standard for risk assessment and pollution rehabilitation. However, knowledge on the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in contaminated site soils is still limited, especially concerning the influential mechanism. With an abundance of soil collections from nine industrial areas in China, the bioavailabilities, as conceptually defined as bioconcentration factors (BCFs) of PAHs were analyzed using biomimetic extraction of hydroxypropyl-β-cyclodextrin (HPCD). Apart from the total content of PAHs varying with the different pyrogenic sources, the BCFs were greatly dependent on the soil physicochemical properties from the spatial scale and inversely proportional to the number of rings. Pearson correlation analysis indicated a weak relationship between bioavailability and the soil dissolved organic matter (DOM), pH and particle size. To incorporate the soil physicochemical properties and structural characteristics of PAHs determined by density functional theory (DFT), the optimum model for bioavailability was developed for BCFs by partial least square (PLS) analysis. The PLS-derived model was shown to be predictive within the applicability domain (AD). The structural characteristics, e.g., molecular polarizability and frontier orbital energy level that favor the soil adsorption of PAH isomers via dispersion interactions, and electron exchanges were indicated to be more impactful on bioavailability than soil environmental factors. However, soil factors should not be neglected, because the pH, DOM, etc. were significantly influential. It makes sense that the higher DOM causes greater bioavailability via increasing the free-dissolved fractions of PAHs. Interestingly, the effect of pH on bioavailability was spectrally validated by excitation-emission matrix (EEM) fluorescence, showing that the interaction between DOM and pyrene strengthened the fluorescence quenching of chromophores with the decline in pH.

Long-term effects of PM2.5 components on hypertension: A national analysis in China

BACKGROUND

Evidence is less about the associations between fine particulate matter (PM_2.5) components and hypertension. We aimed to examine the long-term effects of PM_2.5 components on prevalence of hypertension, diastolic blood pressure (DBP) and systolic blood pressure (SBP).

METHODS

We included participants between March 1, and July 31, 2021, from 13 provinces in China. Geocoded residential address was used for exposure assignment. Mixed-effect regression was used to assess 3-year average concentrations of PM_2.5 and its components (black carbon, organic matter, nitrate, ammonium, and sulfate) on prevalence of hypertension, DBP and SBP with covariate-adjusted. SHapley Additive exPlanation was used to compare the contribution of PM_2.5 components to hypertension, DBP, and SBP. Sex and age subgroup were also analyzed.

RESULTS

We enrolled a total of 113,159 participants aged ≥18 years. Long-term exposure to PM_2.5 and its components (black carbon, organic matter, nitrate, ammonium, and sulfate) had associations with prevalence of hypertension, with the Odds Ratios and 95% confidence interval (CI) of 1.06 (95%CI: 1.03-1.09), 1.07 (95%CI: 1.04-1.09), 1.07 (95%CI: 1.04-1.10), 1.05 (95%CI: 1.01-1.08), 1.03 (95%CI: 1.00-1.06), and 1.03 (95%CI: 1.00-1.04), respectively. Effects of that except for black carbon on DBP with per interquartile upticks of concentration were 0.23 (95%CI: 0.11-0.35), 0.17 (95%CI: 0.04-0.29), 0.35 (95%CI: 0.21-0.48), 0.40 (95%CI: 0.28-0.52), and 0.25 (95%CI: 0.13-0.26), respectively. Ammonium was associated with SBP, corresponding to an increase of 0.18 (95%CI: 0.01-0.35). Males had higher risks of DBP (Z = 2.54-6.08, P < 0.001). Older people were substantially more affected by PM_2.5 and its components. Nitrate showed the highest contribution to hypertension, DBP and SBP compared with other components.

CONCLUSIONS

Long-term exposure to PM_2.5 and its components had adverse consequences on prevalence of hypertension, DBP and SBP, especially for males and older people. Nitrate contributed the highest to hypertension, DBP and SBP. Findings may have implications for pollution and hypertension control.

Weight loss and abnormal lung inflammation in mice chronically exposed to secondary organic aerosols

Secondary organic aerosols (SOAs) have emerged recently as a major component of fine particulate matter. Cell culture studies revealed a role for SOAs in cell oxidative stress, toxicity and inflammation and only a few studies investigated short-term SOA exposure in animal models. Here, mice were chronically exposed to naphthalene-derived SOAs for one and two months. Weight monitoring indicated a marked mass loss, especially in females, following chronic exposure to SOAs. Significantly, a cytokine antibody microarray approach revealed SOA-induced abnormal lung inflammation similar to that seen in cigarette smoke-induced chronic obstructive pulmonary disease (COPD). This in vivo study testifies to the pathogenic role of sub-chronic SOA exposure on human health.

Self-Assembly of Two Tubular Metalloligand-Based Palladium-Organic Cages as Hosts for Polycyclic Aromatic Hydrocarbons

Herein we report two tubular metal-organic cages (MOCs), synthesized by the self-assembly of bidentate metalloligands with different lengths and Pd^II. These two MOCs feature Pd₄L₈-type square tubular and Pd₃L₆-type triangular cage structures, respectively. Both MOCs have been fully characterized by NMR spectroscopy, mass spectrometry, and theoretical calculation. Both cages can be employed for encapsulating polycyclic aromatic hydrocarbons and show high binding affinity toward coronene.

Revealing Internal Rotation and 14N Nuclear Quadrupole Coupling in the Atmospheric Pollutant 4-Methyl-2-nitrophenol: Interplay of Microwave Spectroscopy and Quantum Chemical Calculations

The structure and interactions of oxygenated aromatic molecules are of atmospheric interest due to their toxicity and as precursors of aerosols. Here, we present the analysis of 4-methyl-2-nitrophenol (4MNP) using chirped pulse and Fabry-Pérot Fourier transform microwave spectroscopy in combination with quantum chemical calculations. The rotational, centrifugal distortion, and ¹⁴N nuclear quadrupole coupling constants of the lowest-energy conformer of 4MNP were determined as well as the barrier to methyl internal rotation. The latter has a value of 106.4456(8) cm^-1, significantly larger than those from related molecules with only one hydroxyl or nitro substituent in the same para or meta positions, respectively, as 4MNP. Our results serve as a basis to understand the interactions of 4MNP with atmospheric molecules and the influence of the electronic environment on methyl internal rotation barrier heights.

Association of Endocrine-Disrupting Chemicals with All-Cause and Cause-Specific Mortality in the U.S.: A Prospective Cohort Study

Wide exposure to endocrine-disrupting chemicals (EDCs) poses a great risk on human health. However, few large-scale cohort studies have comprehensively estimated the association between EDCs exposure and mortality risk. This study aimed to investigate the association of urinary EDCs exposure with mortality risk and quantify attributable mortality and economic loss. Multivariable Cox proportional hazards regression models were performed to investigate the association of 38 representative EDCs exposure with mortality risk in the National Health and Nutrition Examination Survey (NHANES). During a median follow-up of 7.7 years, 47,279 individuals were enrolled. All-cause mortality was positively associated with 1-hydroxynaphthalene, 2-hydroxynaphthalene, cadmium, antimony, cobalt, and monobenzyl phthalate. Cancer mortality was positively associated with cadmium. Cardiovascular disease (CVD) mortality was positively associated with 1-hydroxynaphthalene, 2-hydroxynaphthalene, and 2-hydroxyfluorene. Nonlinear U-shaped relationships were found between all-cause mortality and cadmium and cobalt, which was also identified between 2-hydroxyfluorene and CVD mortality. J-shaped association of cadmium exposure with cancer mortality was also determined. EDCs exposure may cause 56.52% of total deaths (1,528,500 deaths) and around 1,897 billion USD in economic costs. Exposure to certain phthalates, polycyclic aromatic hydrocarbons, phytoestrogens, or toxic metals, even at substantially low levels, is significantly associated with mortality and induces high economic costs.

Prospects of emerging PAH sources and remediation technologies: insights from Africa

Remediation of polluted environmental media is critical to realization of the goals of the United Nations Decade on Ecosystem Restoration (UNDER) project. Many natural-resource dependent economies in Africa are characterized by numerous contaminated sites resulting from conventional and artisanal natural-resource mining. Alongside these extractive activities, there are refining, processing, and power plant operations, agriculture, urban, and infrastructure developments that contribute to increased discharges of toxins into the environment, particularly polycyclic aromatic hydrocarbons (PAHs), which are carcinogenic in nature. As a result, human and environmental receptors (i.e., air, water, soil, and biota) face increasing risk of exposure to higher concentrations of PAH. Evidence exists of widespread PAH contamination and in some instances where corrective action has been taken, residual contaminant levels exceeding regulatory thresholds remain in the environment due to the use of inappropriate and unsustainable remedial methods. Considering the long-term harmful effects of PAH on human and ecosystem health, land use, and the complexity of Africa's environmental deterioration, it is essential to explore remediation strategies that benefit both the environment and the economy. This review examined the status, opportunities, and challenges related to the application of emerging green technologies to remediate PAH-contaminated sites in five African countries (South Africa, Nigeria, Angola, Egypt, and Kenya). This paper concludes that bioremediation presents a sustainable option, considering its low net emissions and environmental footprints, and its low economic cost to Africa's poor communities and overburdened economy. However, an integration of biological and physico-chemical approaches could address various compounds and concentrations of PAH contamination.

Supported liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of urinary polycyclic aromatic hydrocarbon metabolites and their application for human biomonitoring

Polycyclic aromatic hydrocarbons (PAHs) are a class of highly lipophilic and ubiquitous, persistent organic pollutants with carcinogenic and mutagenic toxicities. They are a great public health concern, and avoiding exposure to them is a high priority. Human biomonitoring is critical for the evaluation of exposure levels to PAHs by the general population. In this work, we demonstrated the biomonitoring of eleven hydroxylated PAHs (OHPAHs) in urine samples from 226 volunteers from Guangzhou, and evaluated the health risks. The urinary PAH metabolites were released by enzymatic deconjugation, separated, and enriched by supported liquid extraction, and then quantified by ultra-high performance liquid chromatography-tandem mass spectrometry. The limit of quantification of the individual OHPAHs ranged from 10 ng/L to 40 ng/L, and satisfactory recoveries were obtained, ranging from 92.6% to 97.6%. The detection frequencies of the OHPAHs were 100%, and naphthalene metabolites were found at the highest concentrations with a geometric mean of 8.61 μg/L. The mean total OHPAH level in the urine samples of males (13.2 μg/L) was significantly higher than that of females (5.84 μg/L). Pearson correlation analyses indicated significant and positive correlations among urinary OHPAHs. The total estimated daily intake of PAHs was calculated, and a low health risk was obtained by evaluating their hazard quotients and hazard indexes.

Establishing the relationship between Polycyclic Aromatic Hydrocarbons (PAHs) exposure and male infertility: A systematic review

It has been demonstrated that human exposure to environmental chemicals may have sperm genotoxic potentiality. Among the different classes, Polycyclic Aromatic Hydrocarbons (PAHs) have been receiving attention in recent years due to reports of sperm geno-toxicity, a series of reproductive defects and male infertility. This review aims to substantiate the effects of PAHs exposure on male infertility, with focus on the sperm characteristics (count, concentration, volume, motility, DNA damage, and morphology). To this end, international databases such as Cochrane Library, PubMed, Web of Science, Embase Ovid, Scopus, and Google Scholar were used to conduct a systematic search for papers on the subject, based on PRISMA guidelines, published up to 24 March 2022. The Newcastle-Ottawa Scale was subsequently used to assess the quality of the studies. The results showed that there is a significant negative relationship between PAHs metabolites and sperm volume, concentration, motility, morphology, as well as an observed DNA degeneration. Also, the CYP1A1 genotype polymorphisms were considered as a representative of PAHs exposure to infertility; the review highlights that polymorphisms of this genotype were more common in the infertile people. In overall, this work provides a solid summary of the existing works correlating PAHs exposure and male infertility, which could impulse further protective measures and informative campaigns on users, workers, and general population.

Association between polycyclic aromatic hydrocarbon exposure and hypertension among the U.S. adults in the NHANES 2003-2016: A cross-sectional study

The global burden of hypertension, the major cause of cardiovascular disease (CVD) globally, remains unresolved. Exposure to PM2.5 has been linked to hypertension (HTN) in adults and the elderly globally according to previous studies. Nonetheless, evidence on the association of polycyclic aromatic hydrocarbon (PAH) exposure and HTN risk in the general adult population in the United States was limited. To investigate the relationship between PAH exposure and HTN in adults in the United States, cross-sectional data during 2003 and 2016 from the National Health and Nutrition Examination Survey (NHANES) on a stratified multistage random sample of the civilian non-institutionalized population were utilized. After eliminating individuals with incomplete information of interest, the final analysis contained 8951 subjects aged ≥20. In the multivariate logistic regression model, 1-hydroxynaphthalene and 2-hydroxyfluorene were found positively associated with increased risk of HTN among overall participants after adjusting for the covariates. 1-hydroxynaphthalene and 2-hydroxynaphthalene showed positive associations with HTN risk among overweight participants. In the Bayesian kernel machine regression (BKMR) model, 1-hydroxynaphthalene and 2-hydroxyfluorene presented great importance to HTN risk among overall individuals. In the male subgroup analyses by BKMR, 2-hydroxyfluorene presented a positive effect on HTN risk when the remaining OH-PAHs were set at their 25th, 50th, and 75th percentile. Our findings highlight the complexities of estimating the risk of HTN associated with mixed PAH exposure, and additional longitudinal studies are required to determine the exact link between PAH exposure and HTN risk, as well as the underlying mechanisms.

Concentration of Polycyclic Aromatic Hydrocarbons (PAHs) in Human Serum and Adipose Tissues and Stimulatory Effect of Naphthalene in Adipogenesis in 3T3-L1 Cells

Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent classes of environmental pollutants. Some evidence shows that PAHs could be involved in human obesity. However, little is known about the distribution patterns of PAHs in human adipose tissue (AT) and the role of PAHs on adipogenesis/lipogenesis. The aims of this pilot study were to determine concentrations of 16 PAHs defined as high-priority pollutants in the plasma and adipose tissue of French and Polish bariatric patients, as well as their correlation with body mass index (BMI), plasma and AT adipokines expression levels. We finally investigated the role of naphthalene on cell proliferation, viability, and differentiation in 3T3-L1 preadipocytes. The concentration of most PAHs was similar in the three types of AT and it was significantly higher in AT as compared to plasma, suggesting bioaccumulation. Polish patients had higher PAH levels in AT than French ones. Only the concentration of naphthalene in AT was positively correlated with the BMI and serum or adipose chemerin, adiponectin and resistin expression, in French but not in Polish patients, who had significantly higher BMIs. Moreover, naphthalene exposure increased the cell proliferation of 3T3-L1 preadipocytes and lipogenesis, and increased the expression of genes involved in adipogenesis after cell differentiation. Taken together, PAHs and more particularly naphthalene could be an obesogenic molecule and increase the risk of obesity.

Integrated Insights into Source Apportionment and Source-Specific Health Risks of Potential Pollutants in Urban Park Soils on the Karst Plateau, SW China

Polycyclic aromatic hydrocarbons (PAHs) and heavy metal(loid)s (HMs) pose risks to environmental and human health. Identification of priority control contaminants is important in guiding the management and control of these synchronous pollutants. A total of 247 soil samples were collected from 64 urban parks in the karst plateau city of Guiyang in SW China to determine the concentrations, spatial distributions, and health risks of PAHs and HMs. The results indicate that dibenz(ah)anthracene and benzo(a)pyrene are the main PAHs species of high ecological risk, and Cr, Mn, and Ni pose elevated ecological risk among the HMs. Four sources were identified for PAHs (biomass burning, coke oven, traffic sources, and coal burning) and HMs (traffic sources, coal burning, industrial sources, and natural sources). The non-carcinogenic risk (NCR) and total carcinogenic risk (TCR) of PAHs were all determined to be negligible and at acceptable levels, several orders of magnitude below those of HMs. The NCR and TCR values of HMs were relatively high, especially for children (11.9% of NCR > 1; 79.1% of TCR > 10-4). Coal burning and natural sources make the greatest contributions to the NCR and TCR values from karst park soils in Guiyang. Considering HMs bioavailability, NCR and TCR values were rather low, due to the high residual HM fractions. Integrated insights into source specific ecological and human health risk indicate future directions for management and control of synchronous PAH and HM pollution, particularly for karst plateau areas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12403-023-00534-3.

Assessment of inflammatory cytokines in exhaled breath condensate and exposure to mixtures of organic pollutants in brick workers

Brick production causes a lot of pollution in the form of dust, fumes, and toxic substances. Therefore, brick workers are highly exposed to pollutants and present a high risk of developing respiratory diseases. The objective of this research was to determine the exposure to polycyclic aromatic hydrocarbons (PAHs) and toluene in urine and evaluate the effects on health using markers of oxidative stress in exhaled breath condensate (EBC) as well as the exposure to pollutants in suspended particles of the studied area. Exposure to PAHs and toluene was evaluated using hydroxylated markers (OH) of PAHs and hippuric acid in urine, respectively. Cytokines like TNF-α, INF-y, IL-2, IL-4, IL-6, IL-8, IL-10 y GMCSF in EBC were also evaluated. PM_2.5 particles were measured during an 8-h work shift. The results in brick workers presented a total OH-PAHs concentration of 97.3 µg/L and hippuric acid concentration of 0.2 g/L. The environmental concentrations of suspended particles were found within a range of 41.67-3541.6 μg/m³. The median of cytokines oscillated between 11.8 pg/mL to 1041 pg/mL. In conclusion, these results are similar to those of occupations in which there is high exposure to pollutants and populations with lung diseases. For that reason, the brick production sector requires prevention and control strategies against the pollutants emitted.

Quantitative analysis of phenanthrene in soil by fluorescence spectroscopy coupled with the CARS-PLS model†

Polycyclic aromatic hydrocarbons (PAHs) are typical organic pollutants in soil and are teratogenic and carcinogenic. Therefore, rapid and accurate analysis of PAHs in soil can provide a theoretical basis and data support for soil contamination risk assessment. In this work, a fluorescence spectroscopy technique combined with partial least squares (PLS) was proposed for rapid quantitative analysis of phenanthrene (PHE) in soil. At first, the fluorescence spectra of 29 soil samples with different concentrations (0.3–10 mg g⁻¹) of PHE were collected by RF-5301 PC fluorescence spectrophotometer. Secondly, the effects of different spectral preprocessing methods were investigated on the prediction performance of the PLS calibration model. And then, the influence of competitive adaptive reweighted sampling (CARS) wavelength points on the prediction performance of PLS calibration model was discussed. Finally, according to the selected wavelength points, a quantitative analytical model for PHE content in soil was constructed using the PLS calibration method. To further explore the predictive performance of the CARS-PLS calibration model, the predictive results were compared with those of the RAW spectrum-partial least squares calibration model (RAW-PLS) and the wavelet transform-standard normal variation (WT-SNV) calibration model. The CARS-PLS calibration model showed the optimal predictive performance and its coefficient of determination of cross-validation (R_cv²) and root mean square error of 10-fold cross-validation (RMSEcv) were 0.9957 and 18.98%, respectively. The coefficient of determination of prediction set (R_p²) and root mean square error of prediction set (RMSEp) were 0.9963 and 16.13%, respectively. Hence, the CARS algorithm based on fluorescence spectrum coupled with PLS can give a rapid and accurate quantitative analysis of the PHE content in soil.

Fluorescence spectroscopy coupled with CARS-PLS model is successfully used for the rapid quantitative analysis of phenanthrene in soil.

Predictive Models of Gas/Particulate Partition Coefficients (KP) for Polycyclic Aromatic Hydrocarbons and Their Oxygen/Nitrogen Derivatives

Polycyclic aromatic hydrocarbons (PAHs) and their oxygen/nitrogen derivatives released into the atmosphere can alternate between a gas phase and a particulate phase, further affecting their environmental behavior and fate. The gas/particulate partition coefficient (KP) is generally used to characterize such partitioning equilibrium. In this study, the correlation between log KP of fifty PAH derivatives and their n-octanol/air partition coefficient (log KOA) was first analyzed, yielding a strong linear correlation (R2 = 0.801). Then, Gaussian 09 software was used to calculate quantum chemical descriptors of all chemicals at M062X/6-311+G (d,p) level. Both stepwise multiple linear regression (MLR) and support vector machine (SVM) methods were used to develop the quantitative structure-property relationship (QSPR) prediction models of log KP. They yield better statistical performance (R2 > 0.847, RMSE < 0.584) than the log KOA model. Simulation external validation and cross validation were further used to characterize the fitting performance, predictive ability, and robustness of the models. The mechanism analysis shows intermolecular dispersion interaction and hydrogen bonding as the main factors to dominate the distribution of PAH derivatives between the gas phase and particulate phase. The developed models can be used to predict log KP values of other PAH derivatives in the application domain, providing basic data for their ecological risk assessment.

Bacterial Communities Associated with Crude Oil Bioremediation through Composting Approaches with Indigenous Bacterial Isolate

In this study, we aim to investigate the efficiency of crude oil bioremediation through composting and culture-assisted composting. First, forty-eight bacteria were isolated from a crude oil-contaminated soil, and the isolate with the highest crude oil degradation activity, identified as Pseudomonas aeruginosa, was selected. The bioremediation was then investigated and compared between crude oil-contaminated soil (S), the contaminated soil composted with fruit-based waste (SW), and the contaminated soil composted with the same waste with the addition of the selected bacterium (SWB). Both compost-based methods showed high efficiencies of crude oil bioremediation (78.1% and 83.84% for SW and SWB, respectively). However, only a slight difference between the treatments without and with the addition of P. aeruginosa was observed. To make a clear understanding of this point, bacterial communities throughout the 4-week bioremediation period were analyzed. It was found that the community dynamics between both composted treatments were similar, which corresponds with their similar bioremediation efficiencies. Interestingly, Pseudomonas disappeared from the system after one week, which suggests that this genus was not the key degrader or only involved in the early stage of the process. Altogether, our results elaborate that fruit-based composting is an effective approach for crude oil bioremediation.

Deriving freshwater sediment quality guidelines of polycyclic aromatic hydrocarbons using method of species sensitivity distribution and application for risk assessment

Contamination of polycyclic aromatic hydrocarbons (PAHs) in sediment has long been of great concern because of their toxic effects to benthic organisms. Sediment quality guidelines (SQGs) are the basis to evaluate the potential ecological risks of PAHs in sediments. Species sensitivity distribution (SSD) has been widely applied in deriving water quality criteria, but seldom employed in SQGs. In this study, SSD was used to derive the freshwater SQGs for four representative PAHs (naphthalene, phenanthrene, pyrene and benzo[a]pyrene) based on the sediment toxicity results. A linear relationship between the SQGs and octanol-water partition coefficient (log K_OW) was developed, and applied to predict the SQGs of other twelve PAHs. The obtained SQGs were in the range of 0.46 - 1.79 mg/kg with a geometric mean of 0.97 mg/kg, which was proposed as the SQGs for total PAHs. Based on these SQGs, the risk quotients of PAHs in the sediments collected from Haihe River of China were calculated, and the toxic effects were also tested using three representative benthic organisms. As the risk quotients of the PAHs and heavy metals in the sediments were summed up, good correlations were found (p = 0.074 and 0.018) between them and the observed toxicities of the sediments. The SQGs developed for PAHs was promising in ecological risk assessment for contaminated freshwater sediments.

Genetic variants of antioxidant enzymes and environmental exposures as molecular biomarkers associated with the risk and aggressiveness of bladder cancer

Bladder cancer (BC) is one of the top 10 most common tumours worldwide; however, no molecular markers are currently available for tumour management and follow-up. BC could benefit from molecular biomarkers in environmental disease, which provide mechanistic understanding of individual susceptibility to exposure-related cancers and allow characterizing genetic alterations in the molecular pathway for malignancy. This case-control study performed a molecular analysis in 99 BC and 125 controls. Buccal swabs were collected to assess SNPs in eleven genes coding for xenobiotic detoxification enzymes, cellular antioxidant defences, and hormone synthesis and signalling (NAT2 (rs1801280), GPX1 (rs1050450 and rs17650792), TXNRD1 (rs7310505), PRDX3 (rs3740562), PON1 (rs662), SOD1 (rs10432782), SOD2 (rs4880), CAT (rs1001179), CYP17A1 (rs743572) and ESR1 (rs746432)). A structured questionnaire was administered to study participants to assess environmental and dietary chemical exposures. Several miRNAs associated with BC and detoxification/antioxidant pathways were analysed in a subsample of the study population, including miR-93-5p, miR-221-3p, miR-126, miR-27a-3p, miR-193b, and miR-193a-5p. Levels of selected environmental pollutants (polycyclic aromatic hydrocarbons and endocrine disrupting chemicals) were determined in urine from a subsample of BC cases and controls. We found that CYP17A1, CAT, SOD1, ESR1, PON1, and GPX1 (rs17650792) were associated with BC risk. Furthermore, exposure to smoke and/or dust, and alcohol intake were identified as risk factors for BC. Increased urinary levels of benzo[a]pyrene and bisphenol A were observed in BC patients relative to controls, along with an increased expression of miR-193b, miR-27a and miR-93-5p in BC. Nevertheless, further studies with a larger sample size are warranted to confirm these exploratory results. This study also shows that the combination of genetic markers (PON1 and CYP17A1) and miRNA (miR-221-3p and miR-93-5p) open a new scenario in the use of non-invasive biomarkers in the stratification of BC to guide personalized medicine, which is extremely urged in the current clinical setting.

Air Mapping of Polycyclic Aromatic Hydrocarbons and Their Uptake by Crops in the Urban Area of Nice, France

Urban gardening is becoming increasingly popular. Air pollution, which is a major concern in cities might, however, threaten food safety and thus must be assessed. Health risks arise particularly from toxic persistent organic pollutants such as Polycyclic Aromatic Hydrocarbons (PAHs) which are formed by incomplete combustion. A first assessment of crop contamination in two different atmospheric environments in the urban area of Nice reveals a predominance of light PAHs. These pollutants present in the gaseous phase, seem to bioaccumulate while heavy PAHs are absent in vegetation. By understanding the PAH sources and their behavior in the atmosphere but also by analyzing the spatial and temporal data since the European directive in 2004, a link between concentrations found in vegetables grown in experimental gardens and PAH cadastral emission data is presented. The first results could be used as a possible guidance for urban agriculture.

Benzo(a)pyrene and cardiovascular diseases: An overview of pre-clinical studies focused on the underlying molecular mechanism

Benzo(a)pyrene (BaP) is a highly toxic and carcinogenic polycyclic aromatic hydrocarbon (PAH) whose toxicological effects in the vessel-wall cells have been recognized. Many lines of evidence suggest that tobacco smoking and foodborne BaP exposure play a pivotal role in the dysfunctions of vessel-wall cells, such as vascular endothelial cell and vascular smooth muscle cells, which contribute to the formation and worsening of cardiovascular diseases (CVDs). To clarify the underlying molecular mechanism of BaP-evoked CVDs, the present study mainly focused on both cellular and animal reports whose keywords include BaP and atherosclerosis, abdominal aortic aneurysm, hypertension, or myocardial injury. This review demonstrated the aryl hydrocarbon receptor (AhR) and its relative signal transduction pathway exert a dominant role in the oxidative stress, inflammation response, and genetic toxicity of vessel-wall cells. Furthermore, antagonists and synergists of BaP are also discussed to better understand its mechanism of action on toxic pathways.

Investigation of gaseous and solid pollutants emitted from waste tire combustion at different temperatures

Consumer society requires the continuous evolution of products, thus generating a lot of waste. The automotive industry has also undergone significant development, generating 1.5 billion used tires worldwide every year. Landfilling of tires is prohibited and their disposal is therefore a major issue. Although many studies deal with the utilization of tire as a fuel, there is limited research that would specifically describe the relationship between pollutant emissions from tire combustion and the relationship between emitted pollutants and firebox temperature. Based on this, this work aims to investigate flue gas concentrations (CO, CO₂, NO_x, and SO₂) and solid pollutants from tire burned in a lab-scale electrical furnace at firebox temperature from 650 to 900 °C. The decomposition of the CaCO₃ filler during the combustion of the tire has been detected with thermal analytical investigation and combustion experiments. In the case of the CO flue gas pollutant, a second maximum concentration is observed due to the presence of CaCO_3. With the increasing firebox temperature, the size of solid particles decreases, and the mesh structure formed becomes denser. At the same time, the concentration of emitted solid PAHs decreases, dominated by aromatic compounds with smaller number of rings. However, the variation of firebox temperature does not affect the amount of benzo(b)fluoranthene and fluoranthene relative to the total concentration.

Decomposition of Naphthalene by Dielectric Barrier Discharge in Conjunction with a Catalyst at Atmospheric Pressure

In this study, coaxial dielectric barrier discharge (DBD) plasma, in conjunction with a metal oxide catalyst, was used to degrade naphthalene. The characteristics of plasma discharge were studied by measuring voltage and current waveforms and the Lissajous figure. The effects of different parameters of the process on naphthalene decomposition in air were investigated. XRD, BET, and SEM data were used to investigate the nature, specific surface area, and surface morphology of the catalyst. The results show that the mineralization of naphthalene reached 82.2% when the initial naphthalene concentration was 21 ppm and the total gas flow rate was 1 L/min in the DBD reactor filled with Al2O3. The mineralization of naphthalene first increased and then became stable with the increase in treatment time and discharge power. The TiO2 catalyst has more apparent advantages than the two other studied catalysts in terms of the removal efficiency and mineralization of naphthalene due to this catalyst’s large specific surface area, porous structure, and photocatalytic properties. In addition, the introduction of a small amount of water vapor can promote the mineralization and CO2 selectivity of naphthalene. With further increases in the water vapor, Fe2O3 has a negative effect on the naphthalene oxidation due to its small pore size. The TiO2 catalyst can overcome the adverse effects of water molecule attachment due to its photocatalytic properties.

Accumulation of high-molecular-weight polycyclic aromatic hydrocarbon impacted the performance and microbial ecology of bioretention systems

Bioretention has been considered as an effective management practice for urban stormwater in the removal of pollutants including polycyclic aromatic hydrocarbons (PAHs). However, the accumulation of high-molecular-weight (HMW) PAHs in bioretention systems and their potential impact on the pollutants removal performance and microbial ecology are still not fully understood. In this study, comparisons of treatment effectiveness, enzyme activity and microbial community in bioretention systems with different types of media amendments were carried out at different spiking levels of pyrene (PYR). The results showed that the removal efficiencies of chemical oxygen demand (COD) and total nitrogen in the bioretention systems were negatively impacted by the PYR levels. The relative activities of soil dehydrogenase and urease were increasingly inhibited by the elevated PYR level, indicating the declining microbial activity regarding organic matter decomposition. The spiking of PYR negatively affected microbial diversity, and distinct time- and influent-dependent changes in microbial communities were observed. The relative abundance of PAH-degrading microorganisms increased in PYR-spiked systems, while the abundance of nitrifiers decreased. The addition of media amendments was beneficial for the enrichment of microorganisms that are more resistant to PYR-related stress, therefore elevating the COD concentration removal rate by ∼50%. This study gives new insight into the multifaceted impacts of HMW PAH accumulation on microbial fingerprinting and enzyme activities, which may provide guidance on better stormwater management practices via bioretention in terms of improved system longevity and performance.

Vitamin D status in relation to inflammatory risk and albuminuria associated with polycyclic aromatic hydrocarbon exposure in the US population

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with both systematic inflammation and renal dysfunction. Reports have suggested that anti-inflammatory properties of vitamin D may provide protection against renal injury. This cross-sectional study tested the hypothesis that serum 25-hydroxyvitamin D [25(OH)D] moderates the inflammation and albuminuria associated with PAH exposure. Data were obtained from 5,982 subjects aged 20-79 years in the National Health and Nutrition Examination Survey (2001-2010). PAH exposure was estimated by urinary PAH metabolites. Inflammation was defined as serum C-reactive protein (CRP) > 3 mg/L and albuminuria as urinary albumin-to-creatinine ratio > 30 mg/g. The results found that greater PAH exposure was linked with inflammation and albuminuria. Individuals with PAH exposure also tended to have lower 25(OH)D and lower vitamin D was associated with both elevated CRP (Odds ratio [OR] = 1.28, 95% confidence interval [CI] = 1.07-1.54) and urinary albumin (1.35, 95%CI = 1.03-1.77) for any given PAH exposure. Those with lower serum 25(OH)D-to-urinary PAH ratios were likewise at a greater risk of elevated CRP and albuminuria. The findings support prior suggestions that exposure to PAHs is associated with inflammation and albuminuria but suggests further that the risk is higher when vitamin D is lower. Thus, nutritional status becomes an important variable in PAH risk assessment.

The Association between Urinary Polycyclic Aromatic Hydrocarbons Metabolites and Type 2 Diabetes Mellitus

Polycyclic aromatic hydrocarbons (PAHs) are considered to be endocrine disruptors. In this study, the evidence on the association between PAHs and diabetes was systematically reviewed. PubMed, EMBASE, and ISI Web of Science were systematically searched for studies reporting the association between PAHs and diabetes. Of the 698 articles identified through the search, nine cross-sectional studies were included. Seven were conducted in the general population and two in coke oven workers. Fixed-effects and random-effects models were used to calculate the total effect. Subgroup analysis was further carried out according to the types of PAH metabolites. The results showed that the odds of diabetes were significantly higher for the highest category of urinary naphthalene (NAP), fluorine (FLU), phenanthrene (PHEN), and total mono-hydroxylated (OH-PAH) metabolites compared to the lowest category. The pooled odds ratios (OR) and 95% confidence intervals (CI) were 1.52 (95%CI: 1.19, 1.94), 1.53 (95%CI: 1.36, 1.71), 1.43 (95%CI: 1.28, 1.60), and 1.49 (95%CI: 1.07, 2.08), respectively. In coke oven workers, 4-hydroxyphenanthrene (4-OHPh) was significantly correlated with an increased risk of diabetes. Exposure measurements, outcome definitions, and adjustment for confounders were heterogeneous between studies. The results of the current study demonstrate a potentially adverse effect of PAHs on diabetes. Further mechanistic studies and longitudinal studies are needed to confirm whether PAH metabolite levels are causative, and hence associative, with increased diabetes incidences.

Could termites be hiding a goldmine of obscure yet promising yeasts for energy crisis solutions based on aromatic wastes? A critical state-of-the-art review

Biodiesel is a renewable fuel that can be produced from a range of organic and renewable feedstock including fresh or vegetable oils, animal fats, and oilseed plants. In recent years, the lignin-based aromatic wastes, such as various aromatic waste polymers from agriculture, or organic dye wastewater from textile industry, have attracted much attention in academia, which can be uniquely selected as a potential renewable feedstock for biodiesel product converted by yeast cell factory technology. This current investigation indicated that the highest percentage of lipid accumulation can be achieved as high as 47.25% by an oleaginous yeast strain, Meyerozyma caribbica SSA1654, isolated from a wood-feeding termite gut system, where its synthetic oil conversion ability can reach up to 0.08 (g/l/h) and the fatty acid composition in yeast cells represents over 95% of total fatty acids that are similar to that of vegetable oils. Clearly, the use of oleaginous yeasts, isolated from wood-feeding termites, for synthesizing lipids from aromatics is a clean, efficient, and competitive path to achieve "a sustainable development" towards biodiesel production. However, the lacking of potent oleaginous yeasts to transform lipids from various aromatics, and an unknown metabolic regulation mechanism presented in the natural oleaginous yeast cells are the fundamental challenge we have to face for a potential cell factory development. Under this scope, this review has proposed a novel concept and approach strategy in utilization of oleaginous yeasts as the cell factory to convert aromatic wastes to lipids as the substrate for biodiesel transformation. Therefore, screening robust oleaginous yeast strain(s) from wood-feeding termite gut system with a set of the desirable specific tolerance characteristics is essential. In addition, to reconstruct a desirable metabolic pathway/network to maximize the lipid transformation and accumulation rate from the aromatic wastes with the applications of various "omics" technologies or a synthetic biology approach, where the work agenda will also include to analyze the genome characteristics, to develop a new base mutation gene editing technology, as well as to clarify the influence of the insertion position of aromatic compounds and other biosynthetic pathways in the industrial chassis genome on the expressional level and genome stability. With these unique designs running with a set of the advanced biotech approaches, a novel metabolic pathway using robust oleaginous yeast developed as a cell factory concept can be potentially constructed, integrated and optimized, suggesting that the hypothesis we proposed in utilizing aromatic wastes as a feedstock towards biodiesel product is technically promising and potentially applicable in the near future.

Emissions of Carbonaceous Particulate Matter and Ultrafine Particles from Vehicles—A Scientific Review in a Cross-Cutting Context of Air Pollution and Climate Change

Airborne particulate matter (PM) is a pollutant of concern not only because of its adverse effects on human health but also on visibility and the radiative budget of the atmosphere. PM can be considered as a sum of solid/liquid species covering a wide range of particle sizes with diverse chemical composition. Organic aerosols may be emitted (primary organic aerosols, POA), or formed in the atmosphere following reaction of volatile organic compounds (secondary organic aerosols, SOA), but some of these compounds may partition between the gas and aerosol phases depending upon ambient conditions. This review focuses on carbonaceous PM and gaseous precursors emitted by road traffic, including ultrafine particles (UFP) and polycyclic aromatic hydrocarbons (PAHs) that are clearly linked to the evolution and formation of carbonaceous species. Clearly, the solid fraction of PM has been reduced during the last two decades, with the implementation of after-treatment systems abating approximately 99% of primary solid particle mass concentrations. However, the role of brown carbon and its radiative effect on climate and the generation of ultrafine particles by nucleation of organic vapour during the dilution of the exhaust remain unclear phenomena and will need further investigation. The increasing role of gasoline vehicles on carbonaceous particle emissions and formation is also highlighted, particularly through the chemical and thermodynamic evolution of organic gases and their propensity to produce particles. The remaining carbon-containing particles from brakes, tyres and road wear will still be a problem even in a future of full electrification of the vehicle fleet. Some key conclusions and recommendations are also proposed to support the decision makers in view of the next regulations on vehicle emissions worldwide.