Polycyclic Aromatic Hydrocarbons In Samples Research Articles

Fingerprinting and emission rates of particulate organic compounds from typical restaurants in Portugal.

The aim of this study was a detailed chemical characterisation of the particles released during the preparation of popular Portuguese dishes. PM2.5 samples were collected from the exhaust stacks on the roofs of a university canteen, a charcoal-grilled chicken restaurant and a wood-oven roasted piglet restaurant. The speciation of organic compounds was carried out by gas chromatography-mass spectrometry. The canteen was responsible for the lowest emissions of PM2.5, while emissions from the roasted piglet restaurant were the highest. Naphthalene was quantified as the most abundant aromatic compound in particle emissions from the canteen, while phenanthrene, fluoranthene, pyrene and chrysene were the dominant polycyclic aromatic hydrocarbons in samples from the other establishments. Benzo[a]pyrene equivalent concentrations obtained for the charcoal-grilled chicken and piglet restaurant indicate a dangerous carcinogenic potential to human health. Cholesterol was the prevalent sterol. Its highest values were obtained in particles from the charcoal-grilled chicken restaurant (621±233μgg-1 PM2.5). Oleic and palmitoleic were the unsaturated fatty acids identified at highest concentrations (from trace levels to 34.4 and to 6.89mgg-1 PM2.5, respectively). Resin acids, such as dehydroabietic and abietic, were detected in all samples from the wood-oven roasted piglet restaurant. Nicotinamide was the amide detected at highest amount in emissions from the university canteen during the preparation of stews (7.67mgg-1 PM2.5). Levoglucosan and its isomers were identified in all samples from the roasted piglet restaurant, but only the first monosaccharide anhydride was present in emissions from the university canteen and the charcoal-grilled chicken restaurant. Additionally, emission rates were estimated for the most representative compounds, taking into account the specific activity of each restaurant.

Occurrence and distribution of typical semi-volatile organic chemicals (SVOCs) in paired indoor and outdoor atmospheric fine particle samples from cities in southern China.

Interest in the potential human health of semi-volatile organic chemicals (SVOCs) in indoor and outdoor environments has made the exposure assessment and source appointment a priority. In this study, paired indoor and outdoor atmospheric fine particle (PM2.5) samples were collected from 15 homes representing five typical urban cities in southern China. Four typical SVOCs, including 16 congeners of polycyclic aromatic hydrocarbons (PAHs), 13 congeners of organophosphorus flame retardants (OPFRs) and 8 congeners of polybrominated diphenyl ethers (PBDEs), as well as tetrabromobisphenol A (TBBPA) and its three debrominated congeners were analyzed. The highest total concentrations were found for OPFRs, followed by PAHs, PBDEs, and TBBPA. The indoor concentrations of two alkyl-OPFR isomers, tributylphosphate (TBP) and tris (2-butoxyethyl) phosphate (TBEP), were 4.3 and 11 times higher, respectively, than those of outdoors (p<0.05). Additionally, the ratios of indoor to outdoor concentrations of alkyl-OPFR isomers varied greatly, suggesting that these compounds originated mainly from different household goods and products used in individual homes. The outdoor concentrations of PAHs and highly brominated PBDEs (BDE-209) typically exceeded the indoor concentrations. Significant correlations were also found between indoor and outdoor PM2.5 samples for PAHs and BDE-209, indicating that outdoor sources such as vehicle exhausts and industrial activities strongly influence their atmospheric occurrence. Additionally, the concentrations of debrominated TBBPA derivatives were higher than those of TBBPA in over 33% of both indoor and outdoor air particle samples. Nevertheless, our results indicated that inhalation exposure to typical SVOCs posed no non-carcinogenic risks to the human body. Although we observed notable differences in the sources, occurrences, and distributions of typical SVOC congeners, more studies using matched samples are still needed to unambiguously identify important indoor and outdoor sources in order to accurately assess the contributions of different sources and the associated human exposure risks.

PAHs, PCBs and organochlorine pesticides in the atmosphere of Eastern Mediterranean: Investigation of their occurrence, sources and gas-particle partitioning in relation to air mass transport pathways

Thirty-four air samples were collected from 2013 to 2015, at a semi-rural site in Eastern Mediterranean (Island of Crete), to study the atmospheric occurrence of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the gas and particulate phase. Average levels (gaseous and particulate phase) of PAHs (36 compounds, 11–18 ng/m3), PCBs (49 congeners, 77–93 pg/m3) and OCPs (23 substances, 77–140 pg/m3) were comparable to those reported for similar locations worldwide. Multiple-linear regression analysis, performed to relate atmospheric concentrations with meteorological conditions, revealed as main controlling factors local sources for PAHs and long-range transport (LRT) for PCBs and OCPs. The consideration of parent-metabolite ratios for most OCPs excluded fresh inputs. The application of the potential source contribution function (PSCF) identified Black Sea and eastern Balkans as likely sources for PCBs and OCPs. Significant linear correlations (R2 = 0.79–0.98) were determined between the partitioning coefficients (logKp) and partial vapor pressures (logPL0) for most air samples for PAHs and PCBs excepting OCPs. Slope mr values were close to −1 for PAHs and OCPs indicating gas/particle partitioning close to equilibrium. The corresponding mr values for PCBs were shallower (<-0.60) denoting non-equilibrium conditions and potential sampling artefacts. The octanol-air partition coefficient absorption model, logKp-logKoa, did not offer robust evidence for the evaluation of the atmospheric partitioning of the studied compounds. Experimentally determined particle fractions (ϕ) fitted better with the typical remote and rural curves as predicted by the Junge-Pankow model for most PAHs and PCBs but not for OCPs. The Koa-fom absorptive model could not adequately simulate the measured ϕ values for the majority of the compounds.

Influencing factors and health risk assessment of polycyclic aromatic hydrocarbons in groundwater in China

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants. This study investigated the occurrence of 16 PAHs in groundwater of representative regions of China (the cities of Lanzhou, Shijiazhuang, and Golmud and in Du’an County) using a gas chromatograph mass spectrometer. The total concentrations of 16 PAHs (∑PAHs) were in the range 0–29.06 μg/L (average: 594.8 ng/L). Acenaphthylene (Acy) and Naphthalene (Nap) had the highest detected frequency (74.56 %) and highest average concentration (632.7 ng/L), respectively. The average concentration of ∑PAHs in each study area exhibited the following trend: Lanzhou > Golmud > Du’an dry season > Du’an wet season > Shijiazhuang. The dominant PAHs in the study areas comprised mainly 2–4-ring PAHs, i.e., Nap (38.71 %; Shijiazhuang), BaA (40.09 %; Du’an wet season), Ace (16.84 %; Du’an dry season), Nap (43.51 %; Lanzhou), and BaA (57.43 %; Golmud). Overall, the PAHs of 101 samples were derived primarily from combustion and a small number of samples of PAHs originated from petroleum sources. Owing to strong adsorption in the vadose zone, the concentrations of PAHs in Shijiazhuang groundwater were lower than those in the groundwater of Golmud and Du’an. The groundwater in Du’an, Lanzhou and Golmud exhibits potential carcinogenic risk if consumed without further treatment.

Objective Measurement of Carcinogens Among Dominican Republic Firefighters Using Silicone-Based Wristbands

PURPOSE Firefighters around the world are exposed to physical hazards and toxic chemical agents during fire incident response. Occupational epidemiologic studies of the firefighter workforce have documented an excess cancer risk for brain, digestive, genitourinary, and lymphohematopoietic organs compared with the general population. Despite the elevated cancer risk, little is known about what specific types of carcinogenic chemicals first responders encounter during a typical work shift, particularly in low-resources settings, like the Dominican Republic. This pilot study characterizes objective measurements of carcinogenic exposure using passive sampling silicone-based wristbands among Dominican firefighters. METHODS Firefighters from a metropolitan fire service in the Dominican Republic were asked to wear a silicone-based wristband during one typical 24-hour shift. A pre- and postshift survey was administered to the firefighter to assess their self-reported sociodemographic, employment, and work shift characteristics. Wristbands were collected after their 24-hour shift and processed for the type and quantity of polycyclic aromatic hydrocarbons (PAHs), a family of known carcinogenic compounds, to which firefighters were exposed. RESULTS Among 15 firefighters who wore a wristband during their 24-hour shift, 73.3% responded to a fire with an average of 3.7 calls during the shift. Fire incident responses included structural fires (54.5%), outside and other fires (36.4%), and vehicle fires (9.1%). Total PAH exposure was significantly higher among Dominican firefighters who responded to a fire compared with firefighters with no fire during their shift (261 parts per billion [ppb] v 117 ppb, respectively; P = .003). Among the 19 PAHs quantified, low-molecular-weight phenanthrene was present in the highest concentration (32 ppb) among firefighters not responding to fires. CONCLUSION Passive objective sampling of PAHs using silicone-based wristbands among Dominican firefighters showed direct exposure to carcinogenic compounds during a typical 24-hour firefighter shift. Firefighters not attending a fire had lower levels of PAHs, suggesting carcinogenic contaminants are present at the fire station.

Nanostructured octadecylsilica chemically coated stainless-steel fiber for vacuum-assisted HS-SPME sampling of PAHs in soil

An efficient and robust solid-phase microextraction (SPME) fiber was developed for vacuum-assisted sampling of polycyclic aromatic hydrocarbons (PAHs) in solid samples. The surface of a stainless-steel fiber was first oxidized and then coated with nanostructured n-octadecylsilica using the Stöber method, by hydrolysis and condensation of tetraethylorthosilicate in the presence of octadecyltrichlorosilane through a sol–gel strategy. The synthesized sorbent was characterized using scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and Fourier transform infrared spectroscopy (FT-IR). The developed vacuum-assisted headspace SPME (VA-HS-SPME) procedure was coupled with GC-FID and optimized for the analysis of PAHs in soil, using multivariate statistical analysis, based on Box-Behnken design. The calibration graphs for seven PAHs were linear (R2 > 0.995) over 0.001–4000 ng g−1. The limits of detection were found to be 0.1–0.9 pg g−1. The relative standard deviations for six repeated analyses of 100 ng g−1 of the PAHs (using a single fiber) were calculated 3.2–8.7% and fiber-to-fiber reproducibility (n = 6) obtained 5.2–12.34%. The nanostructured octadecylsilica was shown to be substantially robust and durable. It was utilized for ultrasensitive VA-HS-SPME/GC analysis of the PAHs in different polluted soil samples and satisfactory results were obtained, with low matrix effects.

Particle-bound PAH emissions from a waste glycerine-derived fuel blend in a typical automotive diesel engine

Polynuclear or polycyclic aromatic hydrocarbons (PAH) are known to be one of the most dangerous types of compounds of their class due to their carcinogenic potential. Some atmospheric PAH are measured and regulated to quantify the air quality. However, in order to better understand the presence of these compounds in the atmosphere it is crucial to study the PAH emissions sources. In this work, we analyze the particulate-bound PAH emissions, as well as their carcinogenic potential, from a typical baseline diesel engine using a promising alternative fuel obtained from the glycerol surplus in the biodiesel production industry. This advanced biofuel (Mo.bio) is a ternary mixture of residual glycerine-derived fuel (FAGE), a conventional fatty acid methyl ester (FAME) and a diesel fuel. Two operating conditions representative of the conflicting scenarios when studying polluting emissions (speeds of 50 km/h and 70 km/h typical of urban and extra-urban driving conditions) are used. In addition, with the purpose of deepening the understanding of the behavior of this new fuel, tests are carried out modifying the Exhaust Gas Recirculation (EGR) ratio. The PAH samples are collected before the aftertreatment systems in order to assess the possible formation of PAH with this type of fuel and to evaluate the options of the aftertreatment devices. Sampling is carried out using fiber-glass filters, extracting the trapped PAH using Soxhlet method. The analytical procedure (liquid chromatography with fluorescence detection) allows to appreciate differences between the different fuels and modes of operation, observing higher emissions of benzo[a]pyrene (BaP) and dibenz[a,h]anthracene (DahA) for the diesel fuel than for the mixture containing residual glycerine-derived fuel. Therefore, it is concluded that the fossil fuel has a larger carcinogenic potential in these conditions, and that the Mo.Bio fuel may possibly expand the EGR ratio range without increasing the requirement of the particle filter.

A facile cooling-assisted solid-phase microextraction device for solvent-free sampling of polycyclic aromatic hydrocarbons from soil based on matrix solid-phase dispersion technique

Solvent-free analysis of organic pollutants from a complex matrix has attracted significant attention. In this work, we designed and fabricated a facile cooling-assisted solid-phase microextraction device (CA-SPME) that could be used for the solvent-free extraction of volatile and semivolatile compounds from a complex matrix using a commercial SPME probe. Determination of polycyclic aromatic hydrocarbons (PAHs) from soil samples was carried out to evaluate the performance of the designed CA-SPME device. The effects of heating temperature, cooling temperature, extraction time, and moisture content in soil on extraction efficiency were investigated. To enhance the extraction efficiency of the targeted analytes, the matrix solid-phase dispersion technique (MSPD) by grinding soil with silica gels was applied. The results showed that grinding with silica gels promoted the release of PAHs from the soil matrix to the headspace by disrupting the matrix structure, which then facilitated the extraction efficiency. Under optimized conditions, for all of the targeted PAHs, the method exhibited good linearity (40–4000 ng g−1) with regression coefficients (R2) ranging from 0.9586 to 0.9964. The limits of detection and limits of quantification ranged from 4.2 to 8.5 ng g−1 and 14.0–28.5 ng g−1, respectively. Relative standard deviations corresponding to the analysis of spiked soil samples (n = 5) were 8.1–13.4%. The solvent-free analysis of the certified soil sample using the proposed method demonstrated satisfactory results.

The effect of gas versus charcoal open flames on the induction of polycyclic aromatic hydrocarbons in cooked meat: a systematic review and meta-analysis.

Open flames of gas and charcoal can induce polycyclic aromatic hydrocarbons (PAHs) in cooked meat. The current study aimed to compare the effect of gas and charcoal open flames on the induction of PAHs in cooked meat using a meta-analysis approach. A systematic review of the literature was conducted electronically based on the PRISMA guidelines. Experimental studies comparing the PAHs content of cooked meat over open flames of gas and charcoal were searched using the appropriate keywords until June 2018. Of 1137 papers retrieved, 7 with a total sample size of 474 meat samples were used in the meta-analysis. The mean difference (MD) between the gas and charcoal cooking methods in the induction of each PAH was 2.053μg/Kg. (95%CI: 1.022-3.085μg/Kg; P < 0.001). The subgroup analysis of 17 trials indicated the difference between the two cooking methods increases when red meat rather than white meat is cooked (MD in red meat: 3.499μg/Kg; 95%CI: 2.030-4.967; P < 0.0001 vs. MD in white meat: 3.319μg/Kg; 95% CI: 1.689-4.950; P < 0.0001). Interestingly, studies that analyzed meat samples for fewer PAHs (cut-off ≤7) found a much wider difference between gas and charcoal-cooked meat (MD: 5.106μg/Kg; (95% CI: 2.162-8.049; P < 0.001 in studies with ≤7 PAHs vs. MD: 1.447μg/Kg; 95% CI: 0.628-2.266; P < 0.001 in studies with >7 PAHs). It is necessary to avoid open flames of charcoal as the heat source or change the geometry of charcoal-fired cookstoves to prevent fat dripping on the fire and thus, excessive PAHs induction.

Fused-silica capillary internally modified with nanostructured octadecyl silica for dynamic in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons from aqueous media

The internal surface of a fused-silica capillary was made much more porous, more adsorptive and resistant to chemical and mechanical stresses by chemical coating using nanostructured octadecyl silica particles. The modification process was conducted using a simple and green nucleosynthesis procedure. The internally modified capillary was used as an in-tube solid-phase microextraction (IT-SPME) device for the extraction and preconcentration of ultratrace levels of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples, followed by determination using gas chromatography-flame ionization detection (GC-FID) system. Morphology and structure of the sorbent was characterized by FT-IR, SEM and energy dispersive X-ray techniques. The effects of a range of experimental variables on the efficiency of the IT-SPME-GC-FID method were evaluated and optimized. Under the optimal conditions, good linearity (R2 > 0.99) was obtained for the calibration graphs over the range of 1–4000 ng mL−1. Detection limits were 0.22–0.47 ng mL−1 and relative standard deviations were obtained in the range 4.4–10.3%. Recoveries of the spiked samples were found to be 78.7–103.5%. The proposed IT-SPME-GC-FID strategy was applied successfully for the analysis of PAHs in real water samples. The results demonstrated good analytical performances, compared with those reported elsewhere for the sampling and quantification of PAHs in aqueous media.

Polycyclic Aromatic Hydrocarbon Gaseous Emissions from Household Cooking Devices: A Kenyan Case Study.

In developing countries, household energy use is highly variable and complex, yet emissions arising from fuel combustion indoors are typically poorly quantified. Polycyclic aromatic hydrocarbons (PAHs) are emitted during the combustion of organic fuels such as charcoal and biomass. In the present study, multichannel polydimethylsiloxane rubber traps were used for gas-phase PAH sampling and extracted using a low-solvent volume plunger-assisted solvent extraction method. Sixteen US Environmental Protection Agency priority PAHs, primarily in the gas phase, were investigated in indoor air of rural and urban residential homes in coastal Kenya (Mombasa and Taita Taveta Counties) using typical combustion devices of each area. Average gaseous PAH concentrations per household were higher in rural (ranging 0.81-6.09 µg m-3 ) compared to urban (ranging 0-2.59 µg m-3 ) homes, although ambient PAH concentrations were higher in urban environments, likely attributable to traffic contributions. The impact of fuel choice and thereby combustion device on PAH emissions was very clear, with the highest concentrations of PAHs quantified from wood-burning emissions from 3-stone stoves (total PAH averages 46.23 ± 3.24 µg m-3 [n = 6]). Average benzo[a]pyrene equivalent total concentrations were evaluated for the priority PAHs and ranged from not detected to 43.31, 88.38, 309.61, and 453.88 ng m-3 for gas, kerosene, jiko, 3-stone, and improved 3-stone stoves, respectively. Environ Toxicol Chem 2020;39:538-547. © 2019 SETAC.

EMISSÕES DE POLUENTES ATMOSFÉRICOS EM CONDIÇÕES REAIS DE PAVIMENTAÇÃO ASFÁLTICA: MATERIAL PARTICULADO, BLACK CARBON E HIDROCARBONETOS POLICÍCLICOS AROMÁTICOS

Intensive use of asphalt generates pollutants into the atmosphere which are harmful to the environment and worrying for occupational health. The application of asphalt products leads to emissions of significant concentrations of polycyclic aromatic hydrocarbons (PAHs) and particulate matter (PM) to the atmosphere. This paper aims to assess the pollutant emissions into the atmosphere in real conditions of asphalt paving through sampling and quantification of PM, Black Carbon (BC) and PAHs in fine particulate fraction and PAHs in gas phase. Concentration intervals of PM1.0, PM2.5, BC1.0 and BC2.5 found during a highway reconstruction in Londrina/PR were respectively 5.6-20.5; 6.3-24.2; 2.0-6.8 and 1.8-6.5 µg m-3. During asphalt surfacing at the same city’s central bus station, the concentration intervals were 15.1-75.1; 19.7-150; 5.1-14.6 and 4.9-16.2 µg m-3 for PM1.0, PM2.5, BC1.0 and BC2.5, respectively. PAHs in the gas and PM fractions were found in both situations with higher concentrations in the gas phase. The results of this work can provide useful information to society in order to improve practices and promote lower environmental impact and health protection.

Mussel Caging and the Weight of Evidence Approach in the Assessment of Chemical Contamination in Coastal Waters of Finland (Baltic Sea)

Contamination status of coastal areas of Finland (northern Baltic Sea) markedly affected by anthropogenic activities (harbours, shipyards and maritime activity, industry, municipal and agricultural inputs, legacy contamination) was assessed for the first time using the weight of evidence (WOE) approach. The key element of the study was the caging (transplantation) of Baltic mussels (Mytilus trossulus) for the measurement of tissue accumulation of polycyclic aromatic hydrocarbons (PAHs) and applying a suite of biomarkers of biological effects of contaminants. Additional variables included in the assessment were trace metals in seawater, macrozoobenthos, near-bottom oxygen levels and eutrophication indicators. The chemical parameters were supported by passive sampling of PAHs and organotins at the study sites. The integrated approach combining all the line of evidence (LOE) variables into the WOE showed separation of some sites as more affected by hazardous substances than others, with the most contaminated areas found around harbour and ship yard areas. The contaminant levels measured in the different matrices were not alarmingly high at none of the areas compared to many other areas within or outside the Baltic Sea under more heavy anthropogenic impact, rarely exceeding any given threshold values for Good Environmental Status of the EU Marine Strategy Framework Directive. However, significant biological effects were recorded in mussels in the most contaminated sites, signifying that the combined effects caused by the contaminants and other environmental factors are disturbing the health of marine organisms in the area. The results of this successful combined application based on the mussel transplantation method and the WOE approach are highly encouraging for further trials in developing the monitoring of chemical contamination in the Baltic Sea.

Incident command post exposure to polycyclic aromatic hydrocarbons and particulate matter during a wildfire

Wildland firefighters engaged in fire suppression activities are often exposed to hazardous air pollutants such as polycyclic aromatic hydrocarbons (PAHs) and particulate matter (PM2.5) during wildfires with no respiratory protection. Although the most significant exposures to smoke likely occur on the fireline, wildland firefighters may also be exposed at the incident command post (ICP), an area designated for wildfire suppression support operations. Our objective was to characterize exposures of PAHs and PM2.5 near an ICP during a wildfire event in California. We collected area air samples for PAHs and PM2.5, during the first 12 days of a wildfire event. PAH area air samples were actively collected in 12-hr shifts (day and night) using XAD4-coated quartz fiber filters and XAD2 sorbent tubes and analyzed for 17 individual PAHs. Hourly area PM2.5 concentrations were measured with an Environmental Beta Attenuation Monitor. Most PAH concentrations generally had similar concentrations during the day and night. PM2.5 concentrations were higher during the day, due to increased fire activity, than at night. The highest concentrations of the 17 PAHs measured were for naphthalene, phenanthrene, and retene. The location of an ICP may be a critical factor in reducing these potential exposures to firefighters during wildfire events. Additionally, exposures could be reduced by utilizing clean air tents or sleeping trailers with HEPA filtration or setting up smaller camps in less smokey areas closer to the fireline for firefighters. Although measured exposures to PAHs for firefighters from smoke are lower at an ICP, these exposures still contribute to the overall cumulative work exposures.

Simulation and experimental study of FET biosensor to detect polycyclic aromatic hydrocarbons

Abstract In this paper, the DNA/Cu2O-GS nanostructure was simulated to detect polycyclic aromatic hydrocarbons (PAHs) and compared with our experimental results. We use a simulation for calculations based on density functional theory (DFT). In the first step, DNA/Cu2O-GS nanostructure was simulated and adsorption mechanism, the density of states and charge transfer process were investigated in the presence and absence of PAHs using the QUANTUM ESPRESSO software and BoltzTrap computing code. The simulation results showed that Cu2O-GS nanostructure can be well used to adsorption and stabilization of DNA. Also the simulation results of electrical conductivity change showed that DNA/Cu2O-GS nanostructure can be well used as a field effect transistor (FET) to detect PAHs. On the other hand, the electric current changes of the DNA/Cu2O-GS-FET for three samples of PAHs (benzene, toluene, and naphthalene) were experimentally studies. Also current leakage, the sensitivity, and dynamic range of transistor for benzene, naphthalene and toluene experimentally were investigated. The experimental results show that the DNA/Cu2O-GS-FET can use as a biosensor for PAHs. Our simulation and experimental results are in good agreement and this DFT-based simulation idea can use for other biosensors.

Recovery and reactivity of polycyclic aromatic hydrocarbons collected on selected sorbent tubes and analyzed by thermal desorption-gas chromatography/mass spectrometry

This article describes the optimization of methodology for extending the measurement of volatile organic compounds (VOCs) to increasingly heavier polycyclic aromatic hydrocarbons (PAHs) with a detailed focus on recent sorbent tube technology. Although PAHs have lower volatility than compounds such as benzene, toluene, ethylbenzene and xylenes, these semi-volatile compounds can be detected in air and breath samples. For this work, PAHs were captured on sorbent tubes and subsequently analyzed using automated thermal desorption gas chromatography – mass spectrometry (ATD-GC/MS). While many different sorbent tubes are commercially available, optimization for airborne PAH sampling using sorbent tubes has not been previously considered. Herein, several commercially available sorbent tubes, including Carbograph 2 TD/1TD, Tenax TA, XRO-440, and inert-coated PAH tubes are compared to determine the relative recovery for eight PAHs commonly found in the environment. Certain types of sorbent materials were found to be better suited for PAH recovery during thermal desorption, and PAH reaction products were observed on several types of sorbent tubes, including graphitized carbon black sorbents with stainless steel tube materials. As such, selection of sorbent tube media should be carefully considered prior to embarking on a PAH study.

Measurements of gas and particle phase polycyclic aromatic hydrocarbons (PAHS) in Ho Chi Minh city in the period of 2017 to 2018

This study was conducted to assess the distribution of polycyclic aromatic hydrocarbons (PAHs) between gas and particle phase in the ambient air in Ho Chi Minh City in the period of 2017 to 2018. Gas and particle phase PAHs samples were collected at five sites in Ho Chi Minh City in a period between March 2017 and February 2018. Particle phase PAHs were collected on glass fiber filters and gas phase PAHs were adsorbed on polyurethane foams (PUFs). Gas and particle phase PAHs were determined by using high-performance liquid chromatography method (HPLC-FLD). In the rainy season, the results shown that total PAHs concentrations in the gas phase was 43.16 ± 19.36 ng/m3 while that in the particle phase was 5.82 ± 3.96 ng/m3. In the dry season, total PAHs concentrations in the gas phase was 40.66 ± 15.14 ng/m3 and in the particle phase was 4.50 ± 2.54 ng/m3. The total concentration of 14 PAHs in the gas phase (42.08 ± 17.62 ng/m3) accounted for over 85% of the total concentration. High molecular weight PAHs (HMW-PAHs) had the highest concentration in the particle phase, accounting for about 78% of the total concentration of 14 PAHs. In contrast, in the gas phase, low molecular weight PAHs (LMW-PAHs) was dominated, accounting for over 65% of the total concentration of 14 PAHs. Particle fraction was obtained to understand the particle/gas phase partitioning of PAHs in ambient air in Ho Chi Minh City. Moreover, particle fraction and logPL0 have a non-linear correlation. Source apportionment of PAHs was carried out by using PMF model. The PMF results indicate four factors that affect PAHs concentrations in Ho Chi Minh City. In four factors, vehicular emission contributed strongly to PAHs concentrations.&#x0D; &#x0D;

Removal of polycyclic aromatic hydrocarbon (PAH)-contaminated sediments by persulfate oxidation and determination of degradation product cytotoxicity based on HepG2 and ZF4 cell lines.

This study evaluated the use of magnetite (Fe3O4), carbon black (CB), and Fe3O4-CB composites activated by persulfate (PS) at circumneutral pH to oxidize polycyclic aromatic hydrocarbons (PAHs) in marine sediments. In addition, the in vitro cytotoxic activity and apoptotic response of the obtained degradation products were investigated. Chemical analyses showed that the total PAH concentration was 26,263ng/g for sediment samples from an industrial port area. Highly toxic BaP was the main contributor to the TEQ in sediments. Source analyses demonstrated that the PAHs in the sediment were derived from coal combustion. In this study, we found that the PS oxidation processes effectively degrade PAHs at concentration levels of 1.7 × 10-5M at pH6.0. The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay was employed to assess the cytotoxicity of the PAH degradation products before and after Fe3O4/PS, CB/PS, and Fe3O4-CB/PS oxidation treatment using a human hepatoma carcinoma cell line (HepG2) and a zebrafish (Danio rerio) embryonic cell line (ZF4). Each sample extract showed a marked dose-related response, with the cell viability reduced by 82% in the case of HepG2 and 58% in the case of ZF4 at 100μg/mL after the Fe3O4-CB/PS process. The PAH degradation products had different effects on the cell morphologies of the two cell lines. The results suggested that the ZF4 cell model is more sensitive than HepG2 to the toxicity of the PAH samples.

Distribution, sources and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected during different monsoon seasons and haze episode in Kuala Lumpur

This study aimed to determine the distribution and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Kuala Lumpur during different monsoon seasons. The potential sources of PM2.5 were investigated using 16 priority PAHs with additional of biomass tracers namely levoglucosan (LV), mannosan (MN) and galactosan (GL). This study also investigated the cytotoxic potential of the extracted PAHs towards V79-4 cells. A high-volume air sampler (HVS) was used to collect PM2.5 samples for 24 h. PAHs were extracted using dichloromethane (DCM) while biomass tracers were extracted by a mixture of DCM/methanol (3:1) before analysis with gas chromatography-mass spectrometry (GC-MS). The cytotoxicity of the PAHs extract was determined by assessing the cell viability through the reduction of tetrazolium salts (MTT). The results showed that the total mean ± SD concentrations of PAHs during the southwest (SW) and northeast (NE) monsoons were 2.51 ± 0.93 ng m−3 and 1.37 ± 0.09 ng m−3, respectively. Positive matrix factorization (PMF) using PAH and biomass tracer concentrations suggested four potential sources of PM2.5; gasoline emissions (29.1%), natural gas and coal burning (28.3%), biomass burning (22.3%), and diesel and heavy oil combustion (20.3%). Health risk assessment showed insignificant incremental lifetime cancer risk (ILCR) of 2.40E-07 for 70 years of exposure. MTT assay suggested that PAHs extracts collected during SW monsoon have cytotoxic effect towards V79-4 cell at the concentrations of 25 μg mL−1, 50 μg mL−1, 100 μg mL−1 whereas non-cytotoxic effect was observed on the PAHs sample collected during NE monsoon.

Partitioning of polycyclic aromatic hydrocarbons in heterogeneous clusters

The morphologies of heterogeneous clusters of polycyclic aromatic hydrocarbons (PAHs) are investigated using molecular modelling. Clusters of up to 100 molecules containing combinations of the different sized PAHs circumcoronene, coronene, ovalene, or pyrene are evaluated. Replica exchange molecular dynamics simulations using an all-atom force field parameterised for PAHs sample many configurations at high and low temperatures to determine stable low energy structures. The resulting cluster structures are evaluated using molecular radial distances and coordination numbers, and are found to be independent of initial configuration and the cluster sizes studied. Stable clusters consist of stacked PAHs in a core-shell structure, where the larger PAHs are found closer to the cluster core and the smaller PAHs are located on the cluster surface. This work provides novel insight into the molecular partitioning of heterogeneous aromatic clusters, with particular relevance to the structure of nascent soot particles.