大气颗粒物中多环芳烃的索氏提取研究

通过对大气颗粒物中多环芳烃的索氏提取过程中的不同阶段的提取液中多环芳烃的分析 ,绘制了索氏提取曲线 ,发现提取效率主要取决于提取循环次数 ,而与提取浸泡时间关系不大。通过比较 1 1种提取液对加标参考物和实验参考物的索氏提取效率 ,发现常用的环己烷、苯等提取液提取效率很低。提取能力的序列为喹啉 乙醇 >吡啶 乙醇 >丙酮>乙醇 >二氯甲烷 >苯 >环己烷 >石油醚 >丙酮 乙醇 环己烷 >氯仿 >四氢呋喃。     

Comparison of pressurized fluid extraction, Soxhlet extraction and sonication for the determination of polycyclic aromatic hydrocarbons in urban air and diesel exhaust particulate matter

In order to characterize and compare the chemical composition of diesel particulate matter and ambient air samples collected on filters, different extraction procedures were tested and their extraction efficiencies and recoveries determined. This study is an evaluation of extraction methods using the standard 16 EPA PAHs with HPLC fluorescence analysis. Including LC analysis also GC and MS methods for the determination of PAHs can be used. Soxhlet extraction was compared with ultrasonic agitation and pressurized fluid extraction (PFE) using three solvents to extract PAHs from diesel exhaust and urban air particulates. The selected PAH compounds of soluble organic fractions were analyzed by HPLC with a multiple wavelength shift fluorescence detector. The EPA standard mixture of 16 PAH compounds was used as a standard to identify and quantify diesel exhaust-derived PAHs. The most effective extraction method of those tested was pressurized fluid extraction using dichloromethane as a solvent.     

Determination of n-alkanes and polycyclic aromatic hydrocarbons in atmospheric particulate and vapour phases in Oviedo, Spain, by GC-MS

A GC-MS procedure for the determination of hydrocarbons in air samples from Oviedo, Spain, was developed. Air hydrocarbons were sampled with a high volume sampler equipped with a holder containing a glass fiber filter, to trap the particulate phase, and two polyurethane foams to capture hydrocarbons of the vapour phase. Compounds were extracted with CH2Cl2 by Soxhlet extraction and then fractionated using column chromatography with alumina silica. Analyses of the fractions were performed by GC-MS in the electron ionization mode. PAHs and n-alkanes were the compounds examined in this work. Samples collected in the vicinity of the Faculty of Chemistry (a semi-urban area) were analysed. The total concentration of PAHs in the air samples analysed ranged from 28 to 76 ng m(-3). The total concentration of n-alkanes and PAHs in the vapour phase exceeded the concentration in the particulate phase in the samples analysed.     

Concentrations, sources and temporal trends in atmospheric polycyclic aromatic hydrocarbons in a major conurbation

Concentrations of atmospheric PAH were separately determined in total suspended particulate matter and associated vapour phase in ambient air in Birmingham, UK. Samples of 24 h duration were taken simultaneously at two locations (the Bristol Road Observatory Site, BROS, and the Elms Road Observatory Site, EROS) on 44 separate occasions every one to two weeks between October 1999 and January 2001. BROS was 10 m from the busy Bristol Road, 800 m from EROS that was located within the "green space" of the University of Birmingham campus. With the exception of acenaphthene, average concentrations of all measured PAH at BROS exceed those at EROS, with a paired t-test revealing these roadside increments to be significant (p < 0.05) for 9 out of the 16 target PAH, demonstrating the importance of traffic emissions of PAH. Although the declines were not statistically significant (p > 0.05) except for phenanthrene and fluoranthene, concentrations of individual PAH at EROS between July and December inclusive in 1999 and 2000 fell by between 16 and 54% compared with those during the same months in 1997. Multiple linear regression of PAH concentrations against meteorological variables confirmed the influence of the Bristol Road on BROS but not EROS. Cluster analysis of PAH contamination in individual samples showed there to be two statistically distinct groups of samples. One group contained 15 samples, all of which displayed elevated concentrations. Examination of air mass back trajectory data, revealed that these PAH pollution episodes originate due to the combined effects of meteorology and local traffic emissions, rather than as a result of long-range transport. Eighteen 12 h samples were also taken at EROS over the period of the November Bonfire Night festivals of 1999 and 2000. These revealed significantly elevated PAH concentrations on the nights when ignition of bonfires and fireworks would be anticipated to peak. These results are relevant to assessments of the impact of similar "festivals of fire" elsewhere. In particular, retene (7-isopropyl-1-methylphenanthrene) concentrations were especially elevated, indicating it has possible utility as an indicator of wood combustion emissions.     

A source study of atmospheric polycyclic aromatic hydrocarbons in Shenzhen, South China

Air pollution has become a serious problem in the Pearl River Delta, South China, particularly in winter due to the local micrometeorology. In this study, atmospheric polycyclic aromatic hydrocarbons (PAHs) were monitored weekly in Shenzhen during the winter of 2006. Results indicated that the detected PAHs were mainly of vapor phase compounds with phenanthrene dominant. The average vapor phase and particle phase PAHs concentration in Shenzhen was 101.3 and 26.7 ng m^???3, respectively. Meteorological conditions showed great effect on PAH concentrations. The higher PAHs concentrations observed during haze episode might result from the accumulation of pollutants under decreased boundary layer, slower wind speed, and long-term dryness conditions. The sources of PAHs in the air were estimated by principal component analysis in combination with diagnostic ratios. Vehicle exhaust was the major PAHs source in Shenzhen, accounting for 50.0% of the total PAHs emissions, whereas coal combustion and solid waste incineration contributed to 29.4% and 20.6% of the total PAHs concentration, respectively. The results clearly indicated that the increasing solid waste incinerators have become a new important PAHs source in this region.     

Role of volcanic dust in the atmospheric transport and deposition of polycyclic aromatic hydrocarbons and mercury

The role of volcanic ash as scavenger of atmospheric pollutants, in their transport and final deposition to the ground is examined. Attention is focused on polycyclic aromatic hydrocarbons (PAHs) and on particulate mercury (Hgp). The ash-fall deposits studied belong to the 2001 and 2002 eruptive activity of Mount Etna, Southern Italy, and were investigated at three (2001) and four (2002) sites downwind of the major tephra dispersal pattern. The dry deposition of mercury and PAHs was determined, and, in particular, a downward flux to the ground of PAHs (approximately 7.29 microg m(-2) per day) and mercury (750 ng m(-2) per day) was estimated in Catania from October 26 to October 28, 2002. Finally, evidence on the anthropogenic origin of PAHs scavenged from the troposphere by volcanic ash is supported by the analysis of PAH compositions in granulometrically homogeneous fractions.     

A comparison of European and North American atmospheric deposition networks: polycyclic aromatic hydrocarbons and lindane

A comparison between the sampling and analytical methods used by Canadian (IADN) and German (OSPAR) regional monitoring networks for persistent organic pollutants was conducted from September 2002 to October 2003 at a rural site in Ontario, Canada. Polycyclic aromatic hydrocarbons (PAHs) and the currently-used pesticide lindane were measured in precipitation and ambient air samples. Overall the two networks sampling and analytical methods agreed well in their results of deposition (wet and dry particulate). Lindane concentrations between the two networks agreed well in the air samples while too few precipitation samples could be compared to conclude on agreement. The lindane seasonal profile with a peak in spring-early summer was consistent with previous results pointing to the continued use of this pesticide in 2002-2003 in Canada. Annual lindane wet depositions were comparable between the two network methodologies. PAHs concentrations in precipitation and in gas phase agreed well while there was a discrepancy for particulate PAHs in air. This study confirmed that the use of data from the two regional POPs monitoring networks for hemispherical modelling studies is warranted.     

Characteristics and sources of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Shanghai, China

A field campaign was conducted to measure and analyze 13 polycyclic aromatic hydrocarbons (PAHs) in six major zones in the city of Shanghai, P.R. China from August 2006 to April 2007. Ambient air samples were collected seasonally using passive air samplers, and gas chromatography–mass spectroscopy was used in this field campaign. The results showed that there was a sequence of 13 PAHs at Phen > FA > Pyr > Chr > Fl > An > BaA > BbFA > BghiP > IcdP > BkFA > BaP > DahA and the sum of these PAHs is 36.01 ± 10.85 ng/m³ in gas phase. FL, Phen, FA, Pyr, and Chr were the dominant PAHs in gas phase in the city. They contributed 90% of total PAHs in the gas phase. Proportion of measured PAHs with three, four, five, and six rings to total PAHs was 53%, 42%, 3%, and 2%, respectively. The highest concentration of ΣPAHs (the sum of 13 PAHs) occurred in the wintertime and the lowest was in the summer. This investigation suggested that traffic, wood combustion, and metal scrap burn emissions were dominant sources of the concentrations of PAHs in six city zones compared with coal burning and industry emissions. Further, the traffic emission sources of PAHs in the city were attributed mostly to gasoline-powered vehicles compared with diesel-powered vehicles. It was revealed that the seasonal changes in PAHs in the city depended on different source types. Metal scrap burn was found to be the major source of PAHs during the autumn, while the PAH levels in the atmosphere for winter and spring seasons were mainly influenced by wood and biomass combustion. Comparisons of PAHs among different city zones and with several other cities worldwide were also made and discussed.     

Gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) emissions from commercial restaurants in Hong Kong

Commercial cooking emissions are important air pollution sources in a heavily urbanized city. Exhaust samples were collected in six representative commercial kitchens including Chinese restaurants, Western restaurants, and Western fast-food restaurants in Hong Kong during peak lunch hours. Both gaseous and particulate emissions were evaluated. Eight gaseous and twenty-two particulate polycyclic aromatic hydrocarbons (PAHs) were quantified in this study. In the gaseous phase, naphthalene (67-89%) was the most abundant PAH in all of the exhaust samples. The contribution of acenaphthylene in the gaseous phase was significantly higher in emissions from the Chinese restaurants, whereas fluorene was higher in emissions from the Western cooking style restaurants (i.e., Western restaurants and Western fast-food restaurants). Pyrene is the most abundant particulate PAH in the Chinese restaurants (14-49%) while its contribution was much lower in the Western cooking style restaurants (10-22%). Controlled cooking conditions were monitored in a staff canteen to compare the emissions from several different local cooking styles, including deep frying, steaming, and mixed cooking styles (combination of steaming and frying). Deep frying produced the highest amount of total gaseous PAHs, 6 times higher than the steaming. However, steaming produced the highest particulate emissions. The estimated annual gaseous PAH emissions for the Chinese restaurants, Western restaurants, and Western fast-food restaurants were 255, 173, and 20.2 t y(-1) whereas 252, 1.9, and 0.4 t y(-1) were estimated for particulate phase PAH emissions. The study provides useful information and estimates for PAH emissions from commercial cooking exhaust in Hong Kong.     

Characterization of polycyclic aromatic hydrocarbons in fog-rain events

Atmospheric polycyclic aromatic hydrocarbons (PAHs) mainly originate from incomplete combustion or pyrolysis of materials containing carbon and hydrogen. They exist in gas and particle phases, as well as dissolved or suspended in precipitation (fog or rain). Current studies in atmospheric PAHs are predominantly focused on fog and rainwater samples. Some sampling difficulties are associated with fog samples. This study presented the first observation of the characteristics of PAHs in fog samples using a solid phase microextraction (SPME) technique. Eighteen fog samples were collected during ten fog events from March to December 2009 in the Shanghai area. PAHs were extracted by SPME and analyzed by gas chromatography-mass spectrometry (GC-MS). As the compounds were partially soluble in water, with solubility decreasing with increasing molecular weight, low molecular weight (LMW) PAH compounds were universally found in the fog water samples. Naphthalene (NaP), phenanthrene (Phe), anthracene (Ant) and fluoranthene (Flo) were dominant compounds in fog water. The total PAH concentration in fog water ranged from 0.03 to 6.67 μg L(-1) (mean of 1.06 μg L(-1)), and was much higher in winter than in summer. The concentration of PAHs in fog or rain water decreased after undergoing a pre-rain or pre-fog wash. The average concentration of PAHs was higher in fog than in rain. Diagnostic ratio analysis suggested that petroleum and combustion were the dominant contributors to PAHs in urban Shanghai. Backward trajectories were calculated to determine the origin of the air masses, showing that air masses were mostly from the northeast territory.     

Measurements of semivolatile and particulate polycyclic aromatic hydrocarbons in a bus station and an urban tunnel in Salvador,Brazil

Motor vehicles constitute a significant source of polycyclic aromatic hydrocarbon (PAH) emissions to the atmosphere. Particle-phase priority pollutant PAH concentrations and total suspended particle mass (TSP) were measured in the Lapa bus station and the Americo Simas Tunnel, located in the city of Salvador, Brazil. Separate samples were collected at the bus station at different times of the day, including rush- and non-rush-hour periods. The highest concentrations for nearly all 16 priority PAHs measured at the bus station were observed at 18:30 h, with chrysene showing the highest mean value (26.6 ng m-3). The highest average PAH concentrations measured in the tunnel were observed for pyrene (79.4 +/- 11.5 ng m-3) followed by fluoranthene (39.0 +/- 5.2 ng m-3) and chrysene (28.0 +/- 4.17 ng m-3). TSP levels reached 423 micrograms m-3 in the bus station, and values as high as 2 mg m-3 in the tunnel. The measured Salvador tunnel PAH profiles are very similar to the Salvador bus station profiles, and are similar to PAH profiles reported for the Kojouike Tunnel, located in Kurashiki City, Japan, and the Caldecott Tunnel, located in Berkeley, California.     

Preliminary studies of a fast screening method for polycyclic aromatic hydrocarbons in soil by using solvent microextraction-gas chromatography

Solvent microextraction (SME) was applied to the extraction of polycyclic aromatic hydrocarbons (PAHs) from spiked and real environmental soil samples with different matrices. Soil sample was mixed with 7 mL of acetone and 14 mL of water to allow partitioning of the PAHs from the soil to the liquid phase. A 2 microL octane drop suspended from a microsyringe needle tip was then immersed into the stirred solution-soil mixture for extraction. After an 11 min extraction, the octane drop was withdrawn into the syringe and injected directly into the GC for identification and quantification. The whole analysis procedure took 27 min, with an extraction time of 11 min, and a GC separation time of 16 min. A second extraction could be undertaken whilst the GC is running, hence the GC run time currently limits the sample throughput. In this method, a small amount of organic solvent was used for the extraction process, which produced little waste. The limits of detection for lower molecular weight (< 230) PAHs range from 0.13 to 0.36 mg kg-1, and for higher molecular weight (> 250) PAHs are estimated to be between 0.5 and 1.0 mg kg-1, with RSD values generally under 20%. Due to the small volumes of organic solvent used, the consumable cost per extraction is only US$ 0.12. This is the first report of the application of SME to solid samples, and the first report of the use of SME for the analysis of PAHs.     

Sedimentary record of polycyclic aromatic hydrocarbons in a sediment core from a maar lake, Northeast China: evidence in historical atmospheric deposition

A maar lake is an excellent ecosystem to study the atmospheric deposition of pollutants, as its contaminants are primarily by atmospheric deposition. In this study, a sediment core from Sihailongwan Maar Lake, Northeast China, was collected and the historical atmospherically deposited polycyclic aromatic hydrocarbons (PAHs) were analyzed. The concentrations of TPAHs (the sum of the US EPA proposed 16 priority PAHs, excluding naphthalene and pyrene) ranged from 473.9 to 2289 ng g(-1) with a slow increasing stage in the deeper sediments and a sharp increasing stage in the upper sediments. The input rate of TPAHs, especially that of PAH(9) (the sum of fluoranthene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenzo(ah)anthrathene, and benzo(ghi)perylene), correlated well to the Chinese historical socioeconomic data. This indicates that sediment PAHs were mainly derived from human activities and PAH(9) can be regarded as a better indicator of the local socioeconomic development. Source identification suggested that PAHs were originated primarily from mixed sources (e.g., coal and biomass burning and petroleum combustion), except for perylene which was mostly of diagenetic origin. In addition, the down-core PAHs profile clearly illustrated that PAHs sources in Northeast China experienced a transformation from low- and moderate temperature to high-temperature combustion processes, especially after the late 1980s. Additionally, an ecological risk assessment using two redefined biological thresholds (TEQ(ERL) and TEQ(ERM)) indicated that most of the PAHs measured in the present sediment core would not cause an immediate toxic effect; only FLU and PHEN are a potential source of concern for biological impairment.     

原煤二氯甲烷浸取液中多环芳烃分布特征

本文用色谱／质谱／红外联用系统研究了原煤二氯甲烷浸取液中多环芳烃的种类、数量、含量及其分布特征。为进一步研究煤燃烧排放飞灰、烟气、炉渣中多环芳烃分布打下良好基础。     

Concentration, distribution and source apportionment of atmospheric polycyclic aromatic hydrocarbons in the southeast suburb of Beijing, China

Total suspended particle samples and gas phase samples were collected at three representative sampling sites in the southeastern suburb of Beijing from March 2005 to January 2006. The samples were analyzed for 16 US EPA priority PAHs using GC/MS. Concentrations of Sigma PAHs in particle and gas phases were 0.21-1.18 x 10(3) ng m(-3) and 9.5 x 10(2) ng-1.03 x 10(5) ng m(-3), respectively. PAH concentrations displayed seasonal variation in the order of winter>spring>autumn>summer for particle phase, and winter>autumn>summer>spring for gas phase. Partial correlation analysis indicates that PAH concentrations in particle phase are negatively correlated with temperature and positively correlated with air pollution index of SO(2). No significant correlation is observed between gas phase PAHs and the auxiliary parameters. Sources of PAH are identified through principal component analysis, and source contributions are estimated through multiple linear regression. Major sources of atmospheric PAHs in the study area include coal combustion, coke industry, vehicular emission and natural gas combustion.     

Distribution of polycyclic aromatic hydrocarbons in the atmosphere of Hong Kong

This paper reports the monitoring results of eleven polycyclic aromatic hydrocarbons (PAHs), four to six-ring, at two urban sites-Central & Western (CW) and Tsuen Wan (TW) in Hong Kong from January to December 2000; and the findings of a study conducted in 2001 of the partitioning of the gaseous and particulate phases of PAHs. The sum of the eleven PAHs under study (sigmaPAHs) was found to range from 6.46 to 38.8 ng m(-3). The annual mean levels at 12.2 ng m(-3) and 15.8 ng m(-3) for CW and TW respectively are comparable to those recorded for the previous two years and are also within the reported ranges for other metropolitan cities in the Asia Pacific region. Amongst the selected eleven PAHs, fluoranthene and pyrene were the two most abundant found in the urban atmosphere of Hong Kong during the study period accounting for approximately 80%, of the total PAHs. The ratios of benzo(a)pyrene to benzo(g,h,i)perylene (BaP/BghiP) and indeno(1,2,3-cd)pyrene to benzo(g,h,i)perylene (IDP/BghiP) indicate that diesel and gasoline vehicular exhausts were the predominant local emission sources of PAHs. Seasonal variations with high winter to summer ratios for each of the individual PAHs (CW: 1.6-16.7 and TW: 0.82-8.2) and for sigmaPAHs (CW: 1.9 and TW: 1.8) and a spatial variation of BaP amongst the air monitoring stations are noted. Results of correlation studies illustrate that local meteorological conditions such as ambient temperature, solar radiation, wind speed and wind direction have significant impact on the concentrations of atmospheric PAHs accounting for the observed seasonal variations. A snapshot comparison of the concentrations of PAHs at four sites including a roadside site, a rural site and the two regular urban sites CW and TW was also performed using the profiles of PAHs recorded on two particulate episode days in March 2000.     

Source analysis of particulate matter associated polycyclic aromatic hydrocarbons (PAHs) in an industrial city in northeastern China

Particle-associated polycyclic aromatic hydrocarbon (PAH) concentrations were investigated at eight sampling sites during cold periods where heating is used (heating period) (February to March, 2005) and warm periods where heating is not required (non-heating periods) (August to September 2006) in the urban area of Anshan, an iron and steel city in northeastern China. Eleven PAH species were measured using GC-MS. The total average concentrations of PAHs ranged from 46.14 to 385.60 ng m(-3) in the heating period and from 5.28 to 146.40 ng m(-3) in the non-heating period. The lowest concentration of ∑PAHs was observed at Qianshan, a monitoring site far from the city and industrial area, and the highest concentration occurred in the site located at the factory area of Anshan Iron and Steel Incorporation. Moreover, ambient PAH profiles were studied and high molecular weight PAH (including 4-6 rings) species occurred in the high fractions. Toxic equivalent factors analysis gave the potential carcinogenic risks in Anshan. For the heating sampling period, BaP equivalent concentration is in the range of 41.98 to 220.83 ng m(-3), and 9.23 to 126.00 ng m(-3) for the non-heating sampling period. By diagnostic ratio analysis, traffic emission and combustion (coal or biomass) were potential sources for PAHs in Anshan. Finally, PCA results indicated the major sources were vehicle emission, steel industry emission, and coal combustion for both heating and non-heating seasons, which agreed with the results from the diagnostic ratio analysis.     

Receptor modeling for source apportionment of polycyclic aromatic hydrocarbons in urban atmosphere

This study reports source apportionment of polycyclic aromatic hydrocarbons (PAHs) in particulate depositions on vegetation foliages near highway in the urban environment of Lucknow city (India) using the principal components analysis/absolute principal components scores (PCA/APCS) receptor modeling approach. The multivariate method enables identification of major PAHs sources along with their quantitative contributions with respect to individual PAH. The PCA identified three major sources of PAHs viz. combustion, vehicular emissions, and diesel based activities. The PCA/APCS receptor modeling approach revealed that the combustion sources (natural gas, wood, coal/coke, biomass) contributed 19–97% of various PAHs, vehicular emissions 0–70%, diesel based sources 0–81% and other miscellaneous sources 0–20% of different PAHs. The contributions of major pyrolytic and petrogenic sources to the total PAHs were 56 and 42%, respectively. Further, the combustion related sources contribute major fraction of the carcinogenic PAHs in the study area. High correlation coefficient (R ² > 0.75 for most PAHs) between the measured and predicted concentrations of PAHs suggests for the applicability of the PCA/APCS receptor modeling approach for estimation of source contribution to the PAHs in particulates.     

Tenax-TA extraction as predictor for free available content of polycyclic aromatic hydrocarbons (PAHs) in composted sewage sludges

The usability of the solid phase extraction method with Tenax-TA adsorbent for the forecasting of polycyclic aromatic hydrocarbon losses during sewage sludges composting has been evaluated in the present study. Four municipal sewage sludges were composted for 76 days. The PAH content in the sludges ranged from 3674 to 11 236 microg kg(-1). After composting, a significant reduction of PAH content was observed. The range of the PAH sum loss ranged from 29.3 to 48.6%. The share of fraction extracted by Tenax-TA in the sludges at the onset of the composting ranged from 28.1 to 54.0% in relation to the PAH sum, and from 0.31 to 100% for individual PAHs. After 76 days of composting, the presence of Tenax-TA extracted PAHs was still observed in the sludges. A significant reduction of this fraction was noted in the case of three sewage sludges. PAH's Tenax-TA fraction in the case of one sewage sludge did not undergo any changes during composting. A satisfactory prediction of PAH losses by the Tenax-TA method was rarely observed. The best reflection of the PAH losses was observed in the case of fluoranthene, anthracene and indeno[1,2,3-cd]pyrene.