Polycyclic aromatic compounds (PAHs) are formed during incomplete combustion and firefighters are inadvertently at risk of being exposed to these and other hazardous compounds. Exposure to PAHs is ...often estimated by measuring their hydroxylated metabolites (OH-PAH) in urine. Here, an online-SPE LC-MS-MS method was set up for eight OH-PAHs thus increasing sample throughput and minimizing manual handling. The method was validated over a 5-month period and showed good reproducibility with intra- and inter-day variation of 2.4–8.1 % and 1.6–6.5 %, respectively, of low-level samples and accuracy (91.6–104.8 %) for a standard reference material. The method was applied to urine samples from conscripts training to become firefighters to determine the optimal sampling time for this training activity before a large intervention study. In total, six conscripts sampled urine 6–8 times over a 40-hr period during a 3-day training course. All eight metabolites were detected in ≥ 97 % of the samples and showed peak excretion 4–6 hrs after the training corresponding to 8–10 hrs after first exposure. Samples taken the morning after the exercise contained low levels of most metabolites. Consequently, 4–6 hrs post exposure is recommended as the optimal sampling time for quantification of PAH exposure and monitoring of potential differences in exposure.
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•An online-SPE LC-MS-MS method for eight OH-PAHs in urine was developed.•Automatization increased reproducibility, sensitivity and sample through-put.•Urinary excretion profiles of 8 OH-PAHs were determined after firefighting exercise.•All OH-PAHs peaked 4–6 hrs after firefighting exercises.•Most OH-PAH urine levels were low in the morning following the exercise.
Concentrations of 34 unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) and AhR-mediated activities in settled dust samples were determined by a combination of gas ...chromatography–mass spectrometry and an in vitro reporter gene assay (PAH-CALUX). The levels of Σ34PAHs and bioassay-derived benzoapyrene equivalents (CALUX BaP-EQs) were significantly higher in workplace dust from informal end-of-life vehicle dismantling workshops than in common house dust and road dust. In all the samples, the theoretical BaP-EQs of PAHs (calculated using PAH-CALUX relative potencies) accounted for 28 ± 19% of the CALUX BaP-EQs, suggesting significant contribution of aryl hydrocarbon receptor (AhR) agonists and/or mixture effects. Interestingly, the bioassay-derived BaP-EQs in these samples were significantly correlated with not only unsubstituted PAHs with known carcinogenic potencies but also many Me-PAHs, which should be included in future monitoring and toxicity tests. The bioassay responses of many sample extracts were substantially reduced but not suppressed with sulfuric acid treatment, indicating contribution of persistent AhR agonists. Cancer risk assessment based on the CALUX BaP-EQs has revealed unacceptable level of risk in many cases. The application of bioassay-derived BaP-EQs may reduce underestimation in environmental management and risk evaluation regarding PAHs and their derivatives (notably Me-PAHs), suggesting a consideration of using in vitro toxic activity instead of conventional chemical-specific approach in such assessment practices.
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•PAHs, Me-PAHs, and AhR-mediated activities were examined in settled dust.•Contributions of unknown/unidentified compounds were significant in settled dust.•CALUX BaP-EQs correlated with not only PAHs but also Me-PAHs.•The use of bioassay-derived BaP-EQs can reduce underestimation of cancer risk.
The objective of the study was the assessment of the mutagenicity of chemical pollutants adsorbed on suspended particulate matter with aerodynamic diameter < 2.5 μm (PM2.5) in the four seasons. ...Samples were collected from the urban agglomeration of Wroclaw, Poland and evaluated for mutagenicity using two Salmonella typhimurium strains TA98 and TA100 with and without metabolic activation with microsomal fraction S9.
The work covered sampling of suspended dusts in four seasons: summer, spring, autumn and winter. The dust samples were collected on glass filters using air aspirator and the organic matter of PM2.5 was extracted using Soxhlet extractor. The levels of polycyclic aromatic hydrocarbon compounds (PAH), nitro-PAH and dinitro-PAH were determined in the extract.
Variable degree of air pollution with mutagenic substances was determined at the selected study site. A greater, negative effect of chemical compounds on DNA was determined in dust samples collected in the autumn-winter season in comparison to samples collected in the spring-summer season. In the majority of tests, higher mutagenicity was obtained in analyses conducted on total extracts in comparison to tests conducted in the presence of PAH pollutant fractions. The obtained mutagenic ratio values pointed to the presence of chemical compounds with a character of both promutagens and direct mutagens.
Samples collected in the autumn-winter season were observed to have a higher diversity of organic substances absorbed on PM2.5 dusts. Particular samples differed in the total content and percent contribution of particular PAHs, nitro-PAHs, and other organic compounds. In addition, the identified substances included compounds belonging to different chemical classes: aliphatic compounds, cycloalkanes, mono- and bicycling arenes, polycyclic arenes, compounds containing oxygen, nitrogen, and sulphur.
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•Particulate matter PM2.5 was sampled at a site in Wroclaw in four seasons, followed by extraction, fractioning and analysis.•Seasonal variability in mutagenicity was assessed for all pollutants and their fractions: PAH, nitro-PAH, and dinitro-PAH.•A variable degree of air pollution with mutagenic substances was determined depending on the sampling season.
Numerous studies have demonstrated that dozens of polycyclic aromatic hydrocarbons (PAHs) are mutagenic, genotoxic and strongly carcinogenic. PAHs are found to be widely present in foods contaminated ...through multiple paths. Due to their lipophilic nature, these compounds easily accumulate in edible oils and fatty foods where they can range from no detection to over 2000μg/kg. Compared to precursor PAHs, researchers have seldom studied the presence of PAH derivatives, especially in food matrices. This chapter includes the physical and chemical characteristics of PAHs and their types, occurrence, sample pretreatment and instrumental determination methods, and their formation, change and control in edible oils and fatty foods. The occurrence and formation of PAH derivatives in foods are much less investigated compared to those of their precursor PAHs. Although the removal of matrix effects and accuracy remain difficult for current rapid determination methods, a prospective research direction of PAH analysis for large-scale screening is in demand. To date, physical absorption, chemical oxidation and biodegradation have been widely used in PAH removal techniques. Specific types of bacteria, fungi, and algae have also been used to degrade PAHs into harmless compounds. However, most of them can only degrade a range of LPAHs, such as naphthalene, anthracene and phenanthrene. Their ability to degrade HPAHs requires further study. Moreover, it is still a great challenge to maintain food nutrition and flavor during the PAH removal process using these methods.
Polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic pollutants emitted by diesel engines, both in the gas phase and adsorbed onto the surface of particulate matter (PM). There ...remains limited understanding of the complex and dynamic competing mechanisms of PAH formation, growth and oxidation in the gas phase, and their adsorption onto soot and how these processes impact on the abundance and composition of exhaust PAH. Therefore, this paper presents analysis of gas and particulate samples taken from the cylinder and exhaust of a diesel engine during combustion of fossil diesel with the 16 US-EPA priority PAH species identified and quantified. In-cylinder results showed that gas-phase PAHs were more abundant than soot-bound PAHs in the engine cylinder. The in-cylinder PAHs included 2- to 6-ring PAHs; however, 6-ring PAHs were not observed in the soot samples collected from the engine exhaust. Levels of both PM and the total in-cylinder PAHs decreased following a peak at 10 CAD ATDC but subsequently increased significantly during the late combustion phase. The B
P equivalence of PM in the engine cylinder increased during the period of early diffusion to late combustion phase, following an initial decrease during the period of premixed to early diffusion combustion.
Coal and coal gangue are petrogenic sources of polycyclic aromatic hydrocarbons (PAHs), which cause adverse impacts on the environment. Raw coal, cleaned coal, slime, slack gangue, and lump gangue ...from the Pingshuo No. 1 Coal Preparation Plant, China, were analyzed to determine the concentrations and compositions of 16 priority parent PAHs (16PAHs) and their alkylated derivatives (aPAHs). The ∑16PAH and ∑aPAH concentrations in the samples ranged from 18.7 to 139.2 mg/kg and 22.2 to 262.3 mg/kg, respectively, and ranked as follows: cleaned coal > raw coal > slime > lump gangue > slack gangue. Coal gangues had a higher proportion and lower degree of alkylation of 4–6-ring PAHs than coals. A summary analysis of references related to coal and coal gangue diagnostic ratios showed that their ratios could not be used to differentiate them from other PAH sources, indicating that the release of particulate coal and coal gangue would increase the uncertainty of environmental PAH identification results. The diagnostic ratios of coal gangue were relatively concentrated, and comparing the ratio distribution could reveal the coal gangue source PAHs. The toxicity risk of slack gangue was higher than that of lump gangue based on the benzoapyrene-equivalent concentration; hence, more attention should be given to its escape to the environment.
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•Coal and coal gangue are also petrogenic sources of environmental PAHs.•∑aPAH in coal and coal gangue were higher than the corresponding ∑16PAH.•Gangue had higher 4–6-ring PAHs proportion and lower alkylation degree than coal.
Real-Time PCR based assays were developed to quantify Gram positive (GP) and Gram negative (GN) bacterial populations that are capable of degrading the polycyclic aromatic hydrocarbons (PAH) in soil ...and sediment samples with contrasting contamination levels. These specific and sensitive Real-Time PCR assays were based on the quantification of the copy number of the gene that encodes the alpha subunit of the PAH-ring hydroxylating dioxygenases (PAH-RHD
α), involved in the initial step of the aerobic metabolism of PAH. The PAH-RHD
α-GP primer set was designed against the different allele types present in the data base (
narAa,
phdA/
pdoA2,
nidA/
pdoA1,
nidA3/
fadA1) common to the Gram positive PAH degraders such as
Rhodococcus,
Mycobacterium,
Nocardioides and
Terrabacter strains. The PAH-RHD
α-GN primer set was designed against the genes (
nahAc,
nahA3,
nagAc,
ndoB,
ndoC2,
pahAc,
pahA3,
phnAc,
phnA1,
bphAc,
bphA1,
dntAc and
arhA1) common to the Gram negative PAH degraders such as
Pseudomonas,
Ralstonia,
Commamonas,
Burkholderia,
Sphingomonas,
Alcaligenes,
Polaromonas strains. The PCR clones for DNA extracted from soil and sediment samples using the designed primers showed 100% relatedness to the PAH-RHD
α genes targeted. Deduced from highly sensitive Real-Time PCR quantification, the ratio of PAH-RHD
α gene relative to the 16S rRNA gene copy number showed that the PAH-bacterial degraders could represent up to 1% of the total bacterial community in the PAH-contaminated sites. This ratio highlighted a positive correlation between the PAH-bacterial biodegradation potential and the PAH-contamination level in the environmental samples studied.
The objectives of this study were to investigate the mutual effect of the PAHs fluorene and pyrene on their respective biodegradation and dissipation processes in an agricultural soil, and to ...determine the effect of hydroxypropyl-β-cyclodextrin (HPBCD), used to increase the bioavailability of PAHs, on such processes. Fluorene dissipation was primarily due to abiotic processes, although a small contribution from biodegradation was also observed. Therefore, fluorene dissipation did not increase with HPBCD and its presence did not significantly alter the dehydrogenase activity. In contrast to fluorene, pyrene dissipation depended primarily on biotic factors, with endogenous soil microorganisms capable of degrading pyrene, with large increases in dehydrogenase activity. HPBCD increased biodegradation rate of pyrene. The co-contamination of soil with both PAHs did not affect fluorene evolution, but significantly inhibited pyrene biodegradation. The different abilities of soil bacterial consortia to catabolize these PAHs are discussed. Additionally, the possibility that the abiotic loss of fluorene through volatilization had a significant effect on the microbial community biodegradation of both fluorene and pyrene is examined.
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•Interactions between PAHs in co-contaminated soils affect their dissipation.•Fluorene (FLU) dissipation is mainly abiotic and Pyrene (PYR) biotic.•FLU diminishes PYR biodegradation. PYR does not affect FLU dissipation.•Dehydrogenase activity increased in PYR contaminated soil but decreased with FLU.•HPBCD accelerated PYR attenuation in soil but no effect is observed on FLU.
Biochar has been widely used for the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soil, but its mechanism of influencing PAH biodegradation remains unclear. Here, DNA-stable ...isotope probing coupled with high-throughput sequencing was employed to assess its influence on phenanthrene (PHE) degradation, the active PHE-degrading microbial community and PAH-degradation genes (PAH-RHDα). Our results show that both Low-BC and High-BC (soils amended with 1 % and 4 % w/w biochar, respectively) treatments significantly decreased PHE biodegradation and bioavailable concentrations with a dose-dependent effect compared to Non-BC treatment (soils without biochar). This result could be attributed to the immobilisation of PHE and alteration of the composition and abundance of the PHE-degrading microbial consortium by biochar. Active PHE degraders were identified, and those in the Non-BC, Low-BC and High-BC microcosms differed taxonomically. Sphaerobacter, unclassified Diplorickettsiaceae, Pseudonocardia, and Planctomyces were firstly linked with PHE biodegradation. Most importantly, the abundances of PHE degraders and PAH-RHDα genes in the 13C-enriched DNA fractions of biochar-amended soils were greatly attenuated, and were significantly positively correlated with PHE biodegradation. Our findings provide a novel perspective on PAH biodegradation mechanisms in biochar-treated soils, and expand the understanding of the biodiversity of microbes involved in PAH biodegradation in the natural environment.
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•Biochar addition significantly reduced PHE biodegradation with a dose effect.•PHE degrader abundance was the main factor of PAH degradation under biochar effect.•PAH-RHDα gene abundance in heavy DNA fractions better reflect the PAH degradation.•Four genera were firstly linked with PHE biodegradation by DNA-SIP.
Polycyclic aromatic hydrocarbons (PAHs) and their derivatives are legislated contaminants ubiquitous in the environment with well-established determination analytical schemes. However, the ...determination of PAHs is not exempt from being improved by the application of newly developed methods and therefore needs to be reviewed periodically to establish the state of the art. Thus, in this article, we critically review the sample preparation and instrumental methods for determining PAHs in air, water, sediment, soil, biota and microplastics developed in the last 10 years. The advantages and challenges of different analytical techniques, including classical and innovative approaches used to quantify and characterize PAHs are discussed. To conclude, future trends and challenges to be overcome are examined.
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•Current analytical techniques for PAHs are summarized and discussed.•Recent advances within the PAH analysis are critically considered.•Analytical aspects of PAHs determination not solved yet are remarked.•Challenges and expectations for the future are focus on instrumental innovations.
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