Polycyclic Aromatic Hydrocarbons Derivatives Research Articles

Methylated derivatives of polycyclic aromatic hydrocarbons in road dust, green belt soil and parking lot dust: occurrence, spatial distribution and emission sources.

Convenient transportation facilities not only bring the higher standard of living to big cities, but also bring some environmental pollution problems. In order to understand the presence and sources of methylated polycyclic aromatic hydrocarbons (Me-PAHs) in environmental samples and their association with total organic carbon (TOC), 49 Me-PAHs were analyzed in road dust, green belt soil and parking lot dust samples in Harbin. The results showed that the ranges of the total Me-PAHs (ΣMe-PAHs) content in road dust were 221-5826ng/g in autumn and 697-7302ng/g in spring, and those in green belt soil were 170-2509ng/g and 155-9215ng/g in autumn and spring, respectively. And ΣMe-PAHs content in parking lot dust ranged from 269 to 2515ng/g in surface parking lots and from 778 to 10,052ng/g in underground parking lots. In these samples, the composition profile of Me-PAHs was dominated by 4-ring Me-PAHs. The results of diagnostic ratios and principal component analysis (PCA) indicated that petrogenic and pyrogenic sources were the main sources of Me-PAHs in the samples. Spearman correlation analysis showed that there was no correlation for Me-PAHs in road dust and green belt soil on the same road. Furthermore, there was a significant positive relationship (0.12 ≤ R2 ≤ 0.67, P < 0.05) between Me-PAHs concentrations and the TOC content. This study demonstrated the presence of Me-PAHs with high concentrations in the road environment samples of Harbin.

Development and Field Application of a Diffusive Gradients in Thin-Films Passive Sampler for Monitoring Three Polycyclic Aromatic Hydrocarbon Derivatives and One Polycyclic Aromatic Hydrocarbon in Waters

Polycyclic aromatic hydrocarbon (PAH) derivatives are widely present in the environment, and some are more hazardous than their parent PAHs. However, compared to PAHs, PAH derivatives are less studied due to challenges in monitoring as a result of their low concentrations in environmental matrixes. Here, we developed a new passive sampler based on diffusive gradients in thin films (DGT) to monitor PAH derivatives and PAHs in waters. In the laboratory study, the XAD18-DGT device exhibited high adsorption rates and was demonstrated to be suitable for deployment in environmental waters on the timescale of months. The diffusion coefficients, D, were 5.30 × 10−6 cm2 s−1, 4.51 × 10−6 cm2 s−1, 4.03 × 10−6 cm2 s−1 and 3.34 × 10−6 cm2 s−1 for 9-fluorenone (9-FL), 1-chloroanthraquinone (1-CLAQ), 9-nitroanthracene (9-NA) and phenanthrene (Phe), respectively, at 25 °C. The DGT device’s performance was independent of pH, ionic strength, deployment time and storage time, indicating it can be widely used in natural waters. In the field study, the target pollutant concentrations measured by the DGT are in good accordance with those determined via grab sampling. Then, the DGT devices were utilized to quantify PAH derivatives and PAHs in several rivers in Hefei, China. This work demonstrates the feasibility of using the DGT technique to detect trace PAH derivatives and PAHs in waters.

Annona Muricata L. extract restores renal function, oxidative stress, immunohistochemical structure, and gene expression of TNF-α, IL-β1, and CYP2E1 in the kidney of DMBA-intoxicated rats.

Introduction: 7,12-dimethylbenz (a) anthracene (DMBA) is a harmful polycyclic aromatic hydrocarbon derivative known for its cytotoxic, carcinogenic, and mutagenic effects in mammals and other species. Annona muricata, L. (Graviola; GRV) is a tropical fruit tree traditionally well-documented for its various medicinal benefits. This investigation is the first report on the potential antioxidant and antinfammatory reno-protective impact of GRV against DMBA-induced nephrotoxicity in rats. Methods: Forty male albino rats were allocated into four equal groups (n = 10). The 1st group served as the control, the 2nd group (GRV) was gastro-gavaged with GRV (200mg/kg b.wt), the 3rd group (DMBA) was treated with a single dose of DMBA (15mg/kg body weight), and the 4th group (DMBA + GRV) was gastro-gavaged with a single dose of DMBA, followed by GRV (200mg/kg b.wt). The GRV administration was continued for 8weeks. Results and Discussion: Results revealed a significant improvement in renal function, represented by a decrease in urea, creatinine, and uric acid (UA) in the DMBA + GRV group. The antioxidant potential of GRV was confirmed in the DMBA + GRV group by a significant decline in malondialdehyde (MDA) and a significant increase in catalase (CAT), superoxide dismutase (SOD), glutathione S transferase (GST), and reduced glutathione (GSH) compared to DMBA-intoxicated rats; however, it was not identical to the control. Additionally, the antiinflammatory role of GRV was suggested by a significant decline in mRNA expression of cytochrome P450, family 2, subfamily e, polypeptide 1 (CYP2E1), tumor necrosis factor-alpha (TNF-α), and interleukin 1 beta (IL-1β) in the DMBA + GRV group. Moreover, GRV improved the histopathologic and immunohistochemical expression of TNF-α, CYP450, and IL1β in DMBA-intoxicated kidney tissue. Conclusively, GRV is a natural medicinal product that can alleviate the renal injury resulting from environmental exposure to DMBA. The reno-protective effects of GRV may involve its anti-inflammatory and/or antioxidant properties, which are based on the presence of phytochemical compounds such as acetogenins, alkaloids, and flavonoids.

Indoor air levels of polycyclic aromatic compounds (PAC) in public buildings with creosote impregnated constructions – A pilot case study using passive samplers

Creosote has been used in Sweden as a wood preservative in buildings since the 19th century. These buildings can function as workplaces, homes, and cultural buildings to which the public has access. Creosote contains polycyclic aromatic hydrocarbons (PAH) which are well known carcinogens. To understand exposure and risks in an indoor environment, it is important to determine air levels of parent PAHs as well as the more toxic nitrated and oxygenated PAH derivatives (NPAH, OPAH).This study aims to investigate indoor air levels of polycyclic aromatic compounds (PACs) e.g., PAH, NPAH, OPAH and dibenzothiophenes in buildings containing creosote sources and whether these levels pose a health risk.Four cultural buildings were studied, all located within a radius of 130 m. Two were known to have creosote sources, and two had not. Polyurethane foam passive air samplers (PUF-PAS) were used to indicate possible point sources. PUF-PAS measurements were performed for one month in each building winter and summer. Simultaneously, PAC outdoor level measurements were performed.Buildings with creosote impregnated constructions had notably higher indoor air levels of PAC (31–1200 ng m−3) compared to the two buildings without creosote sources (14–45 ng m−3). The PAH cancer potency (sum of benzo[a]pyrene equivalents (BaPeq)) was more than one order of magnitude higher in the buildings containing creosote impregnated wood compared to reference buildings. The highest value was 5.1 BaPeq ng m−3 which was significantly higher than the outdoor winter measurement (1.3 BaPeq ng m−3). Fluoranthene and phenanthrene, with significant distribution in gas phase, but also several particulate NPAHs contributed significantly to the total cancer risk. Thus, creosote containing buildings can still contaminate the indoor air with PACs despite being over a hundred years old. The PUF-PAS was shown to be a good tool providing quantitative/semiquantitative measures of PACs exposure in indoor microenvironments.

Pyrene and its derivatives increase lung adverse effects by activating aryl hydrocarbon receptor transcription

Derivatives of polycyclic aromatic hydrocarbons (PAHs) pose significant threat to environment and human health due to their widespread and potential hazards. However, adverse effects and action mechanisms of PAH derivatives on human health have not been attempted yet. Herein, we chose pyrene and its derivatives (1-hydroxypyrene, 1-nitropyrene, and 1-methylpyrene) to investigate adverse effect mechanism to human lungs using in vitro and in vivo methods. Results showed that pyrene derivatives have higher lung health risks than original pyrene. They can activate AhR, subsequently affecting expression of downstream target genes CYP1A1 and CYP1B1. The binding energies of pyrene and its derivatives ranged from −16.07 to −27.25 kcal/mol by molecular dynamics simulations, implying that pyrene and its derivatives acted as agonists of AhR and increased adverse effects on lungs. Specifically, 1-nitropyrene exhibited stabler binding conformation and stronger AhR expression. In addition, sensitivity of pyrene and its derivatives to AhR activation was attributed to type and number of key amino acids in AhR, that is, pyrene (Leu293), 1-nitropyrene (Cys333, Met348, and Val381), 1-hydroxypyrene (Leu293 and Phe287), and 1-methylpyrene (Met348). In summary, we provide a universal approach for understanding action mechanisms of PAH derivatives on human health, and their adverse effects should be taken seriously.

Increased concentration of PAH derivatives in biochar-amended soil observed in a long-term experiment

During biochar preparation or application some toxic substances may be formed. The established limitations of the content of polycyclic aromatic hydrocarbons (PAHs) aim to monitor the fate of PAHs in the life cycle of biochar. The latest studies have revealed that besides PAHs, some of their derivatives with confirmed toxicity are formed. There has been no policy regards PAH derivatives in biochar yet. The aim of the presented studies was the estimation the changes in the content of PAHs and their derivatives during the agricultural application of biochar. A pot experiment with grass revealed that in a short time, both the content of PAHs and their derivatives was reduced. Similarly, when biochar was added to soil in a long-term experiment, the content of determined derivatives was below the limit of detection, whereas interestingly, the content of pristine PAHs increased with time. Co-addition of biochar and sewage sludge increased the content of PAHs and their derivatives indicating potential environmental hazard due to their presence. However, the key point is the estimation of the bioavailability of PAHs and their derivatives as only the bioavailable fraction is revealing the environmental hazard.

Nitro substituent caused negative impact on occurrence and development of atherosclerotic plaque by PM2.5-bound polycyclic aromatic compounds

PM2.5 exposure is a significant risk factor for the occurrence and development of atherosclerosis. Polycyclic aromatic hydrocarbons (PAHs) play prominent roles in PM2.5-related toxicity. However, the nitrated derivatives of PAHs, nitrated polycyclic aromatic hydrocarbons (NPAHs), have strong oxidizing properties due to the nitro substituents. Thus, the in vivo and in vitro experiments exposure to benzo[a]pyrene (BaP) and 6-nitro benzo[a]pyrene (NBaP) were conducted to evaluate the effect of nitro substituent on the atherosclerosis due to (or attributable to) PAHs. The results showed that NBaP exposure induced the inhibition of human umbilical vein endothelial cells (HUVECs) viability and cell morphology damage via more severe oxidative stress than BaP exposure. Furthermore, exposure to PM2.5-bound NBaP caused dyslipidemia in the Apolipoprotein E-deficient (ApoE−/−) mice, including the increment of total cholesterol, triglycerides, low-density lipoprotein cholesterol, and malondialdehyde levels, and the decrement of high-density lipoprotein cholesterol levels, superoxide dismutase and glutathione peroxidase levels in serum and aorta. Furthermore, histology showed atherosclerotic plaque in the aorta of ApoE−/− mice. However, there were no significant differences of the physiological and pathological changes between BaP and control groups. Thus, NPAHs induced endothelial dysfunction and dyslipidemia via severe oxidative stress, and further accelerated the occurrence and development of atherosclerosis compared with the parent PAHs. Our findings provide the first evidence that nitro substituent caused much severer negative health impact of polycyclic aromatic compounds, which highlight the significance of NPAHs in health risk estimation of polycyclic aromatic compounds.

Profiles, exposure assessment and expanded screening of PAHs and their derivatives in one petroleum refinery facility of China

This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in one Chinese petroleum refinery facility. It was found that, following with high concentrations of 16 EPA PAHs (∑Parent-PAHs) in smelting subarea of studied petroleum refinery facility, total derivatives of PAHs [named as XPAHs, including nitro PAHs (NPAHs), chlorinated PAHs (Cl-PAHs), and brominated PAHs (Br-PAHs)] in gas (mean= 1.57 × 104 ng/m3), total suspended particulate (TSP) (mean= 4.33 × 103 ng/m3) and soil (mean= 4.37 × 103 ng/g) in this subarea had 1.76–6.19 times higher levels than those from other subareas of this facility, surrounding residential areas and reference areas, indicating that petroleum refining processes would lead apparent derivation of PAHs. Especially, compared with those in residential and reference areas, gas samples in the petrochemical areas had higher ∑NPAH/∑PAHs (mean=2.18), but lower ∑Cl-PAH/∑PAHs (mean=1.43 × 10−1) and ∑Br-PAH/∑PAHs ratios (mean=7.49 × 10−2), indicating the richer nitrification of PAHs than chlorination during petrochemical process. The occupational exposure to PAHs and XPAHs in this petroleum refinery facility were 24–343 times higher than non-occupational exposure, and the ILCR (1.04 × 10−4) for petrochemical workers was considered to be potential high risk. Furthermore, one expanded high-resolution screening through GC Orbitrap/MS was performed for soils from petrochemical area, and another 35 PAHs were found, including alkyl-PAHs, phenyl-PAHs and other species, indicating that profiles and risks of PAHs analogs in petrochemical areas deserve further expanded investigation.

Characterization of scrubber water discharges from ships using comprehensive suspect screening strategies based on GC-APCI-HRMS

An extended suspect screening approach for the comprehensive chemical characterization of scrubber discharge waters from exhaust gas cleaning systems (EGCSs), used to reduce atmospheric shipping emissions of sulphur oxides, was developed. The suspect screening was based on gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) and focused on the identification of polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives (alkyl-PAHs), which are among the most frequent and potentially toxic organic contaminants detected in these matrices. Although alkyl-PAHs can be even more abundant than parent compounds, information regarding their occurrence in scrubber waters is scarce. For compound identification, an in-house compound database was built, with 26 suspect groups, including 25 parent PAHs and 23 alkyl-PAH homologues. With this approach, 7 PAHs and 12 clusters of alkyl-PAHs were tentatively identified, whose occurrence was finally confirmed by target analysis using GC coupled with tandem mass spectrometry (GC-MS/MS). Finally, a retrospective analysis was performed to identify other relevant (poly)cyclic aromatic compounds (PACs) of potential concern in scrubber waters. According to it, 18 suspect groups were tentatively identified, including biphenyls, dibenzofurans, dibenzothiophenes and oxygenated PAHs derivatives. All these compounds could be used as relevant markers of scrubber water contamination in heavy traffic marine areas and be considered as potential stressors when evaluating scrubber water toxicity.

A Systematic Review of Polycyclic Aromatic Hydrocarbon Derivatives: Occurrences, Levels, Biotransformation, Exposure Biomarkers, and Toxicity.

Polycyclic aromatic hydrocarbon (PAH) derivatives constitute a significant class of emerging contaminants that have been ubiquitously detected in diverse environmental matrixes, with some even exhibiting higher toxicities than their corresponding parent PAHs. To date, compared with parent PAHs, fewer systematic summaries and reanalyses are available for PAH derivatives with great environmental concerns. This review summarizes the current knowledge on the chemical species, levels, biotransformation patterns, chemical analytical methods, internal exposure routes with representative biomarkers, and toxicity of PAH derivatives, primarily focusing on nitrated PAHs (NPAHs), oxygenated PAHs (OPAHs), halogenated PAHs (XPAHs), and alkylated PAHs (APAHs). A collection of 188 compounds from four categories, 44 NPAHs, 36 OPAHs, 56 APAHs, and 52 XPAHs, has been compiled from 114 studies that documented the environmental presence of PAH derivatives. These compounds exhibited weighted average air concentrations that varied from a lower limit of 0.019 pg/m3 to a higher threshold of 4060 pg/m3. Different analytical methods utilizing comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC × GC-TOF-MS), gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF-MS), comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC × GC-QQQ-MS), and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), that adopted untargeted strategies for the identification of PAH derivatives are also reviewed here. Additionally, an in-depth analysis of biotransformation patterns for each category is provided, including the likelihood of specific biotransformation reaction types. For the toxicity, we primarily summarized key metabolic activation pathways, which could result in the formation of reactive metabolites capable of covalently bonding with DNA and tissue proteins, and potential health outcomes such as carcinogenicity and genotoxicity, oxidative stress, inflammation and immunotoxicity, and developmental toxicity that might be mediated by the aryl hydrocarbon receptor (AhR). Finally, we pinpoint research challenges and emphasize the need for further studies on identifying PAH derivatives, tracking external exposure levels, evaluating internal exposure levels and associated toxicity, clarifying exposure routes, and considering mixture exposure effects. This review aims to provide a broad understanding of PAH derivatives' identification, environmental occurrence, human exposure, biotransformation, and toxicity, offering a valuable reference for guiding future research in this underexplored area.

On the aromaticity and stability of benzynes in the ground and lowest-lying triplet excited states.

In this work, we have revisited the aromaticity of benzyne isomers at the unrestricted density functional theory level (UDFT) using the energetic, magnetic, and delocalization criteria. In addition, this last criterion has also been analyzed employing complete active space (CASSCF) calculations. The results show conservation of aromaticity in these monocycles. Additionally it is observed that this trend is maintained in polycyclic aromatic hydrocarbon derivatives such as biradical didehydrophenanthrenes. Do these results imply a violation of Baird's rule? The answer is No, because this conservation in aromaticity is due to the loss of hydrogen atoms affects only the electronic σ skeleton and exerts a minor influence on the π cloud. Additionally, we have analyzed the relative stability of benzyne isomers and their relationship with experimental ΔES-T values. According to the literature, the stability of the benzynes in the singlet state is due to an effective interaction between the electrons of the biradical centers; however, this effect is completely reversed in the triplet state, which explains why the para isomer has the lowest ΔES-T gap.

Inhalation bioaccessibility and risk assessment for PM-bound organic components: Co-effects of component physicochemical properties, PM properties, and sources

Inhalation bioaccessibility and deposition in respiratory tracts of organic components in atmospheric particulate matter (PM) are key factors for accurately estimating health risks and understanding human exposures. This study evaluated the in-vitro inhalation bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) and PAH derivatives, phthalic acid esters (PAEs), polychlorinated biphenyls (PCBs), and organophosphate flame retardants (OPFRs) in size-resolved PM from a Chinese megacity. The bioaccessibility ranged from 0.2% to 77.8% in the heating period (HP), and from 0.7% to 94.2% in the non-heating period (NHP). Result suggests that less hydrophobic organics might be more bioaccessible. Bioaccessibility of medium logKow organics in sizes > 0.65 µm was significantly inhibited by high carbon fractions, indicating the co-effects. Then, this is the first study to explore effects of sources on inhalation bioaccessibility of organics. Coal and biomass combustion in HP and traffic emission in NHP negatively correlated with bioaccessibility. Secondary particles also negatively correlated with bioaccessibility of medium logKow organics. Incremental lifetime cancer risk (ILCR) and non-cancer risk (HQ) for all measured components in PM10 were estimated after considering the bioaccessibility and deposition efficiencies and the HQ and ILCR were within the acceptable range. BaP and DEHP were strong contributors to HQ and ILCR, respectively.

Influence of Exposure Pathways on Tissue Distribution and Health Impact of Polycyclic Aromatic Hydrocarbon Derivatives

Influence of Exposure Pathways on Tissue Distribution and Health Impact of Polycyclic Aromatic Hydrocarbon Derivatives

Biomarkers for polycyclic aromatic hydrocarbons in human excreta: recent advances in analytical techniques-a review.

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that are generated by the incomplete combustion of organic materials. The main anthropogenic sources of PAHs are the combustion of solid fuels for heating purposes, illegal waste incineration, road transport and industries based on fossil fuels. PAHs can easily enter the body because they are present in all elements of the environment, including water, soil, air, and food. Due to their ubiquitous presence, PAHs, may exert a harmful effect on human health. Assessing PAH exposure through biomonitoring mostly involve techniques to measure the concentration of 1-hydroxypyrene in human urine. Nevertheless, through recent progress in analytical techniques, other common metabolites of PAHs in human biospecimens can be detected. A scientific literature search was conducted to determine which hydroxy derivatives of PAHs are markers of PAHs exposure and to reveal the leading sources of these compounds. Techniques for analyzing biological samples to identify OH-PAHs are also discussed. The most frequently determined OH-PAH in human urine is 1-hydroxypyrene, the concentration of which reaches up to a dozen ng/L in urine. Apart from this compound, the most frequently determined biomarkers were naphthalene and fluorene metabolites. The highest concentrations of 1- and 2-hydroxynaphthalene, as well as 2-hydroxyfluorene, are associated with occupational exposure and reach approximately 30ng/L in urine. High molecular weight PAH metabolites have been identified in only a few studies. To date, PAH metabolites in feces have been analyzed only in animal models for PAH exposure. The most frequently used analytical method is HPLC-FLD. However, compared to liquid chromatography, the LOD for gas chromatography methods is at least one order of magnitude lower. The hydroxy derivatives naphthalene and fluorene may also serve as indicators of PAH exposure.

Assessment of atmospheric pollution by oxygenated and nitrated derivatives of polycyclic aromatic hydrocarbons in two regions of the Czech Republic

In this study, a method for monitoring 16 representatives of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and six oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) in airborne particulate matter (PM) was developed and validated. Soxhlet extraction, followed by solid phase extraction (SPE) on silica, was used to isolate the target compounds. Instrumental analysis was performed by gas chromatography coupled with (tandem) mass spectrometry (GC-MS(/MS)) operated in electron impact (EI) and negative ion chemical ionization (NICI) modes. GC-EI-MS/MS was selected for further experiments due to its higher selectivity of measurement and ability to measure derivatives simultaneously with 20 commonly analyzed PAHs (EU + US EPA priority list). This is the first study documenting the simultaneous analysis of OPAHs, NPAHs, and parent PAHs in a single run. This analysis strategy was successfully validated at two concentration levels of artificial contamination, i.e., 0.8 and 4 ng per filter, with recoveries in the 70–104% range and less than 23% repeatability. The newly developed method was used for the analysis of 45 air samples from two cities in the Czech Republic, namely Ceske Budejovice and Most (a place with heavy industry), and two sampling seasons (February vs. May 2017). Five representatives were found in all samples from the oxy-PAH group, with 9,10-anthraquinone (9,10-ANTQ) being the most abundant (0.010–2.49 ng m−3 air). Three major nitro-PAHs, namely 9-nitroanthracene (9-nANT), 2-nitrofluoranthene (2-nFA), and 1-nitropyrene (1-nPYR), were found in 89%, 96%, and 33% of the samples, respectively, found in concentration ranges of <0.60–902, <0.60–276, and <0.60–117 pg m−3 air. Slightly higher levels of oxy- and nitro-PAHs were found in Ceske Budejovice compared to Most, but the difference was not statistically significant (p-value >0.05). A statistically significant difference was observed between February and May, where the concentrations in February were up to 20 and 50 times higher for individual oxy- and nitro-PAHs, respectively, in both regions. The diagnostic ratio 2-nFA/1-nPYR >5 showed that indirect emissions were the primary nitro-PAH source in Most of nitro-PAHs in Most and in both sampling campaigns. In Ceske Budejovice, the opposite trend was observed in winter, i.e. 2-nFA/1-nPYR <5, indicating direct emissions as the main source. In summary, direct emissions of OPAHs and NPAHs originate from fossil (transportation-related) and solid fuel (heating-related) combustion. In contrast, indirect emissions are related to atmospheric reactions of PAHs with OH radicals (spring, winter) and NO3 radicals (winter). The total TEQB[a]P was higher in winter than spring, with higher inhalation cancer risk.

Impact of fossil and non-fossil fuel sources on the molecular compositions of water-soluble humic-like substances in PM2.5 at a suburban site of Yangtze River Delta, China

Abstract. Atmospheric humic-like substances (HULIS) affect the global radiation balance due to their strong light absorption at the ultraviolet wavelength. The potential sources and molecular compositions of water-soluble HULIS at a suburban site in the Yangtze River Delta from 2017 to 2018 were discussed, based on the results of the radiocarbon (14C) analysis and combining the Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) technique in this study. The 14C results showed that the averaged non-fossil-fuel source contributions to HULIS were 39 ± 8 % and 36 ± 6 % in summer and winter, respectively, indicating significant contributions from fossil fuel sources to HULIS. The Van Krevelen diagrams obtained from the FT-ICR-MS results showed that the proportions of tannin-like and carbohydrate-like groups were higher in summer, suggesting significant contribution of HULIS from biogenic secondary organic aerosols (SOAs). The higher proportions of condensed aromatic structures in winter suggested increasing anthropogenic emissions. Molecular composition analysis on the CHO, CHON, CHOS, and CHONS subgroups showed relatively higher intensities of high O-containing macromolecular oligomers in the CHO compounds in summer, further indicating stronger biogenic SOA formation in summer. High-intensity phenolic substances and flavonoids, which were related to biomass burning and polycyclic aromatic hydrocarbon (PAH) derivatives indicating fossil fuel combustion emissions, were found in winter CHO compounds. Besides, two high-intensity CHO compounds containing condensed aromatic ring structures (C9H6O7 and C10H5O8) identified in the summer and winter samples were similar to those from off-road engine samples, indicating that traffic emissions were one of the important fossil fuel sources of HULIS at the study site. The CHON compounds were mainly composed of nitro compounds or organonitrates with significantly higher intensities in winter, which were associated with biomass burning emissions, in addition to the enhanced formation of organonitrates due to high NOx in winter. However, the high-intensity CHON molecular formulas in summer were referring to N-heterocyclic aromatic compounds, which were produced from the atmospheric secondary processes involving reduced N species (e.g., ammonium). The S-containing compounds were mainly composed of organosulfates (OSs) derived from biogenic precursors, namely long-chain alkane and aromatic hydrocarbon, which illustrate the mixed sources of HULIS. Generally, different policies need to be considered for each season due to the different seasonal sources (i.e., biogenic emissions in summer and biomass burning in winter for non-fossil-fuel sources, traffic emissions and anthropogenic SOA formation in both seasons, and additional coal combustion in winter). Measures to control emissions from motor vehicles and industrial processes need to be considered in summer. Additional control measures on coal power plants and biomass burning should be applied in winter. These findings add to our understanding of the interaction between the sources and the molecular compositions of atmospheric HULIS.

Evaluation of Environmentally Relevant Nitrated and Oxygenated Polycyclic Aromatic Hydrocarbons in Honey.

In this work, a novel analytical methodology for the extraction and determination of polycyclic aromatic hydrocarbon derivatives, nitrated (NPAH) and oxygenated (OPAH), in bee honey samples was developed. The extraction approach resulted in being straightforward, sustainable, and low-cost. It was based on a salting-out assisted liquid-liquid extraction followed by liquid chromatography-tandem mass spectrometry determination (SALLE-UHPLC-(+)APCI-MS/MS). The following figures of merit were obtained, linearity between 0.8 and 500 ng g-1 for NPAH and between 0.1 and 750 ng g-1 for OPAH compounds, coefficients of determination (r2) from 0.97 to 0.99. Limits of detection (LOD) were from 0.26 to 7.42 ng g-1 for NPAH compounds and from 0.04 to 9.77 ng g-1 for OPAH compounds. Recoveries ranged from 90.6% to 100.1%, and relative standard deviations (RSD) were lower than 8.9%. The green assessment of the method was calculated. Thus, the Green Certificate allowed a classification of 87 points. This methodology was reliable and suitable for application in honey samples. The results demonstrated that the levels of nitro- and oxy-PAHs were higher than those reported for unsubstituted PAHs. In this sense, the production chain sometimes transforms foods as direct carriers of contaminants to consumers, representing a concern and demonstrating the need for routine control.

Environmental and health impacts of household energy conversion on PAHs and their derivatives in PM2.5 in typical areas of northern China

Heavy use of solid fuels in rural households of northern China emits huge amounts of fine particulate matter (i.e., PM2.5) that pose notable indoor air pollution and severe inhalation health risks. In this study, the environmental and health benefits of clean energy substitution were accessed by monitoring indoor and personal exposure to polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and pulmonary function and biological parameters. After substitutions of traditional lump coal and biomass fuels by clean coal, indoor concentrations of parent PAHs (p-PAHs), alkylated PAHs (a-PAHs), oxygenated PAHs (o-PAHs), and nitro PAHs (n-PAHs) reduced by 71 %, 32 %, 70 %, and 76 %, while personal exposure concentrations decreased by 82 %, 87 %, 93 %, and 86 %, respectively. However, the proportion of low molecular weight PAHs increases, especially for 2-ring a-PAHs and 3-ring n-PAHs. Domestic solid fuel burning induces greater damage to the small airway than the large airway. Pulmonary function parameter reductions in the clean coal group are much less than those in the other two fuel groups. Salivary interleukin-6 (IL-6) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) significantly correlated with PAH species, among which p-PAHs and PAHs derivatives strongly with IL-6 and 8-OHdG, respectively. The correlation between PAHs and biomarkers in urine is insignificant. In addition, the use of clean coal can reduce the cancer risk for the four classes of PAHs by 60 %–97 %, mainly owing to the lower contributions from p-PAHs and o-PAHs. The result of the study provides scientific support for clean energy retrofit and an understanding of health benefits from solid fuel substitutions.

Distinct seasonal variability of source-dependent health risks from PM2.5-bound PAHs and related derivatives in a megacity, southwest China: Implications for the significance of secondary formation

In contrast to polycyclic aromatic hydrocarbons (PAHs) which have been regularly monitored, the source-dependent health risk of their derivatives in ambient environment has not been well understood, especially regarding seasonal variability. In this study, oxygenated and nitrated PAHs (OPAHs and NPAHs) in PM2.5 samples from different seasons in urban Chongqing were analyzed and compared with PAHs from a human health perspective. Benzo[a]pyrene equivalent concentrations (BaPeq) were annually averaged at 6.13 ± 8.97 ng/m3 (n = 118) in the present study, with highest levels in winter followed by spring, autumn, and summer. The BaPeq values of OPAHs were higher than PAHs in spring and summer with seasonal averaged value up to 3.7 times of that for PAHs, manifesting significant underestimation of the health impact if only PAHs were considered. Incremental lifetime cancer risk (ILCR) model results suggested that the potential cancer risks were accumulated mostly from inhalation exposure during infancy and adulthood. Furthermore, in comparison with PAHs, OPAHs, mainly 6H-Benzo[c,d]pyren-6-one, had significant contribution to cancer risks (annually averaged at 58.3 %). Source-dependent cancer risks based on positive matrix factorization model denoted secondary formed PAH derivatives as a critical contributor to cancer risk, particularly in spring and summer (attributed to about 61 % of ILCR). The enhanced secondary formation of PAH derivatives during spring and summer was partially justified by diagnostic ratios and further analysis revealed that higher temperature, higher O3 level, and lower relative humidity besides stronger solar intensity during these two seasons as the most likely causes of this seasonal variation. Results in this study emphasizes that more knowledge on the formation and toxicity of OPAHs is imperative, especially in the context of complex PM2.5-ozone pollution in China.

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.