Average Polycyclic Aromatic Hydrocarbons Concentrations Research Articles

Pollution characteristics and health risk assessment of polycyclic aromatic hydrocarbons in atmospheric fine particulates PM<sub>2.5</sub> in Jinhua City

Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances with teratogenic, carcinogenic and mutagenic properties. They are widely detected in atmospheric fine particulates PM2.5. Measuring the concentrations of PAHs in PM2.5 is helpful to understand their pollution levels, environmental sources and fates, which further provides important information for pollution prevention and ecological risk assessment. As semi-volatile organic chemicals, PAHs could partition between air and atmospheric particulates when they are released into the atmosphere. Most of 16 priority PAHs, especially PAHs with 4–6 aromatic rings, mainly exist in particulates, which are frequently taken as research targets for source analysis. Jinhua city locates in the center of Zhejiang Province, and is an important transportation hub in East China. The city air has been polluted by traffic exhaust and coal combustion. However, the atmospheric PAHs levels, pollution characteristics and risk to human health are still unknown. In this study, 30 PM2.5 samples were collected during Dec. 2013–Jan. 2014 in winter atmosphere in Jinhua City. Then 16 priority PAHs were analyzed by GC-MS/MS. The total average concentration of PAHs is 62.75±27.87 ng m - 3, and benzo( b )fluoranthene (15.13%), pyrene (13.05%), fluoranthene (12.47%) and chrysene (10.62%) have the highest concentrations, accounting for more than 50% percentage of Σ PAHs. The components distribution indicates 4-ring PAHs contribute the largest ratio (43.45%) in PM2.5, followed by 5-ring PAHs (39.78%) and 6-ring PAHs (8.43%). Generally, 4-ring PAHs are characteristic emissions of coal combustion and vehicle exhaust mainly contain 5/6-ring PAHs. T -test shows the contents of 4- and 5/6-ring PAHs have no statistical variance (Sig=0.683), indicating coal combustion and vehicle exhaust have similar contributions to the PAHs in PM2.5. This result was also proved by source apportionment which is carried out by analyzing several feature ratios of specific PAHs. The human health risk from PAHs was further evaluated by lifetime cancer risk (ILCR) assessment models. The ILCR values for inhalation exposure to PAHs were calculated to be 4.29/4.41×10 - 6 for children, 7.98/8.25×10 - 6 for teen-agers, 4.92/5.34×10 - 6 for adults, respectively, indicating a low risk of cancer of PAHs in atmospheric PM2.5 in winter in Jinhua.

Seasonal Trends of Atmospheric PAHs in Five Asian Megacities and Source Detection Using Suitable Biomarkers

The most prevalent pollutant, polycyclic aromatic hydrocarbons (PAHs) is now plenteously distributed in the global atmosphere. We recently quantified 36 polycyclic aromatic hydrocarbons (PAHs) associated with aerosols (particulate matter: PM) in five Asian cities: Tokyo (Japan), Beijing (China), Kolkata (India), Hanoi (Vietnam), and Kuala Lumpur (Malaysia). Average atmospheric PAH concentrations (Σ12 PAHs-ng m^(–3)) increased in the order of Kuala Lumpur (2.99) ≈ Tokyo (3.95) ＜ Hanoi (7.99) ＜＜ Kolkata (63.5) ＜＜ Beijing (142.8). The most abundant PAHs in PM samples in these cities were chrysene, benz[a]anthracene, benzofluoranthenes, benzo[a]pyrene, and benzo[e]pyrene. We used the PAH compositions, especially the relative abundances of alkylated PAHs, and hopanes to determine vehicle exhaust-derived PAHs, and levoglucosan as a tracer for biomass burning, especially from wood combustion. Vehicle exhaust contributed to atmospheric PAHs in all cities, indicated by higher ratios of (C_(30)17α)/total PAHs and MPAHs/PAHs than coal and wood combustion products. Coal combustion contributed also in winter aerosols in Beijing, indicated by higher abundance of β isomers i.e., 17β21β (H)-C30hopane (C_(30)17β) and 17β21β (H)-C_(29)hopane (C_(29)17β) signifying mass use of coal for heating. The ratio of levoglucosan/PAHs was high in Kuala Lumpur and Hanoi, suggesting greater inputs of PAHs from biomass burning there.

Quantitative ecological risk assessment of inhabitants exposed to polycyclic aromatic hydrocarbons in terrestrial soils of King George Island, Antarctica

This study aims to conduct a quantitative ecological risk assessment of human exposure to polycyclic aromatic hydrocarbons (PAHs) in terrestrial soils of King George Island, Antarctica. Generally, the average PAH concentrations detected in King George Terrestrial Soils (KGS) were appreciably lower than those of World Marine Sediments (WMS) and World Terrestrial Soils (WTS), highlighting the fact that Antarctica is one of the most pristine continents in the world. The total concentrations of twelve probably carcinogenic PAHs (ΣPAHs: a sum of Phe, An, Fluo, Pyr, B[a]A, Chry, B[b]F, B[k]F, B[a]P, Ind, D[a,h]A and B[g,h,i]P) were 3.21 ± 1.62 ng g−1, 5749 ± 4576 ng g−1, and 257,496 ± 291,268 ng g−1, for KGS, WMS and WTS, respectively. In spite of the fact that KGS has extremely low ΣPAHs in comparison with others, the percentage contribution of Phe is exceedingly high with the value of 50%. By assuming that incidental ingestion and dermal contact are two major exposure pathways responsible for the adverse human health effects, the cancer and non-cancer risks from environmental exposure to PAHs were carefully evaluated based on the “Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions” memorandum provided by US-EPA. The logarithms of cancer risk levels of PAH contents in KGS varied from −11.1 to −7.18 with an average of −7.96 ± 7.73, which is 1790 times and 80,176 times lower than that of WMS and WTS, respectively. All cancer risk levels of PAH concentrations observed in KGS are significantly (p < 0.001) lower than those of WMS and WTS. Despite the Comandante Ferraz Antarctic Station fire occurred in February 25th, 2012, both the cancer and non-cancer risks of environmental exposure to PAHs were found in “acceptable level”.

Removal of Polycyclic Aromatic Hydrocarbons by Extensive Green Roofs

In this study,four pilot-scale extensive green roof facilities with different substrate compositions were developed. In 8 rainfall events, concentrations of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in effluent of these facilities were investigated and compared with effluents of asphalt roofing, the blank control roof and rain water. Average PAHs concentrations in the effluent of these four facilities, asphalt roofing and blank control facilities were 145, 166, 151, 160, 900, 270 ng·L-1, respectively. The PAHs mass concentrations discharged by four simulation facilities were significantly lower than asphalt roofing and blank control roof. From the perspective of the mass loading control, all four simulation facilities could effectively control roof runoff PAHs load with an average load reduction rate of 71.76% compared with the blank control roof. Interception and adsorption by green roof substrates was the main removal way for PAHs. Facilities' PAHs removal efficiency could be improved by increasing the substrate thickness with the same substrate composition. Transforming traditional asphalt roofing into extensive green roof was an effective way to control PAHs emissions from roof runoff.

Characterization, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons in urban soil of Nanjing, China

Polycyclic aromatic hydrocarbons (PAHs) are widespread in the urban environment, particularly in urban soil, which are affected by intensive human activities. The purpose of this study was to determine the levels of PAHs in urban areas of Nanjing, China, apportion their sources, and evaluate their health risk. One hundred eighty topsoil samples (0–10 cm) were collected from 180 grids of 1 km × 1 km in the main urban area of Nanjing, China, which was divided into four different land use classes. All the soil samples were analyzed for 16 US Environmental Protection Agency (US EPA) priority PAHs by HPLC. Source of PAHs was explained by isomer ratios and principal component analysis, and health risk of PAHs was assessed by benzo[a]pyrene (BaP) toxic equivalency factors. The average concentration of PAHs ranged from 41.19 to 7016.65 μg kg−1, with an average of 979.59 μg kg−1. PAHs in soil characterized by different land uses, in decreasing order, were as follows: university (UN) > traffic area (TA) > forest park (FP) > residential area (RA). PAHs in FP soils were mainly attributed to biomass combustion, while TA soils exhibited clear traffic emission characteristics. PAHs for UN and RA came from mixed sources. A principle component analysis (PCA) and ordinary kriging map indicated coal combustion and vehicle emissions as the major contributors to PAHs in Nanjing urban soils, respectively. A health risk assessment based on the BaP toxic equivalency approach indicated a potential risk level of PAHs. The mean value of PAH concentrations in UN was the highest. However, the maximum was detected in TA. The PAHs in soil samples originated mainly from coal combustion and petroleum combustion sources. There was a potential health risk level of PAHs in Nanjing urban areas.

Concentration, Water-Soluble Ionic and Polycyclic Aromatic Hydrocarbons Composition and Sources of PM2.5 During Summer in Hongshan District, Wuhan

Atmospheric PM2.5 samples were collected in Hongshan district, Wuhan from June 12th to July 22th, 2014. This study analyzed the characteristics and chemical composition of PM2.5, and the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) were analyzed by gas chromatography-mass spectrometry (GC-MS), to discuss the pollution sources and formation mechanism. The results indicated the total concentrations of PM2.5 ranged from 36.41 to 220.02 μg·m-3, with the mean of 97.38 μg·m-3. and the exceeding criteria rate was 59.26%. Furthermore, the concentration of PM2.5 correlated significantly with wind speed in meteorological parameters, when the wind speed increased, the concentration of PM2.5 showed a trend of decline. The water-soluble ionic components of PM2.5 were SO42-, NO3-, NH4+ and K+ which accounted for 40.67%, and the aerosol partial acid. The influencing factors of formation process of SO42- were different from those of NO3-, and NH4HSO4 and (NH4)2SO4 were the main compounds of NH4+ in PM2.5. The average concentration of PAHs in PM2.5 was 11.30 ng·m-3, and the dominant compounds were 4-6 ring PAHs. Industrial waste gas and vehicle emissions were the sources of PM2.5. The various sources of the PAHs had contribution of 83.90% from vehicle emission and combustion of coal, 10.17% from petroleum sources, and 5.08% from coking emission. The concentration of toxic benzo[a]pyrene equivalent (TEQBaP) ranged from 0.22 to 11.19 ng·m-3 (mean, 1.74 ng·m-3), and the exceeding criteria rate was 7.41%.

Worldwide distribution of polyclyclic aromatic hydrocarbons in urban road dust

Polycyclic aromatic hydrocarbons (PAHs) are considered as one of the most important groups of organic environmental contaminants due to their toxicity, persistence and ubiquity. PAHs have been monitored in urban road dust at various locations worldwide in about last three decades. Resuspension of road dust containing PAHs is an important route of human exposure to PAHs. This paper collates the available information on reported concentrations of PAHs in urban road dust at various worldwide locations classified as industrial, residential, traffic, city and commercial and other areas, reported sources of PAHs and related interpretations. The available information has been reviewed and documented country-wise. Variation in PAHs concentrations over various worldwide locations have been scrutinized, and interestingly, most of the reported average PAHs concentrations were found to be distributed within a very narrow range of values, implying only little variation in average PAH concentrations in spite of great distances between locations, climatic variation and differences in anthropogenic activities.

Fate of iron and polycyclic aromatic hydrocarbons during the remediation of a contaminated soil using iron-activated persulfate: A column study

Remediation of contaminated soils under flow-through conditions is an issue of great interest since it provides a better approach to real case applications than batch experiments. In this work, a column filled with soil, artificially spiked and aged for three months with Phenanthrene (PHE), Anthracene (ANT), Pyrene (PYR) and Benzo(a)pyrene (BaP), was treated for 25days with persulfate (PS) activated by Fe3+ and nanoparticles of zerovalent iron (nZVI). Effects of type of iron fed into the column (Fe3+ or nZVI) and nZVI concentration were studied. PS inlet concentration was 0.2mmolcm−3 and residence time in the column was close to 1.72days. Iron, PS and polycyclic aromatic hydrocarbons (PAHs) concentration, as well as pH, were monitored during treatment. Concentration profiles of iron and PAHs were observed along the column, with higher iron concentrations and higher PAHs removal efficiencies in the closest sections to the column entrance. BaP and ANT were completely depleted regardless the conditions used, but PHE and PYR showed higher resistance to oxidation, achieving near a 90% removal in the closest sections to the injection source in all runs, but decreasing significantly with column length. Besides, natural degradation of ANT resulted in the formation 9.10-anthraquinone (ATQ), an oxy-PAH which showed higher resistance than PHE and PYR. Although higher PAHs removal efficiencies were achieved when nZVI was used as activator, only a moderate improvement was noticed when the highest concentration of nZVI was used as a consequence of radical scavenging by an excess of Fe2+. Finally, a kinetic model based on runs performed in batch, from a previous work, was able to predict the experimental average concentrations of PAHs in the column when Fe3+ was used as activator.

Baseline of polycyclic aromatic hydrocarbons in the surface sediment and sea cucumbers (Holothuria leucospilota and Stichopus hermanni) in the northern parts of Persian Gulf

Polycyclic aromatic hydrocarbons (PAHs) were determined in the surface sediments and in the sea cucumbers (Holothuria leucospilota and Stichopus hermanni) from around six Islands in the northern parts of Persian Gulf. The ranges of the average concentrations of PAHs in surface sediments, H. leucospilota and S. hermanni were 10.33–186.16ngg−1 dw, 12.49–505.44ngg−1 dw and 8.08–389.39ngg−1 dw, respectively. The spatial distribution of PAHs reveals that pollutant concentration is relatively higher at the western parts of Persian Gulf. International sedimentary quality guidelines (TEL-PEL) indicated a low probability of harmful effects to benthic organisms. PAH source identification showed that the PAHs in the sediments come from pyrogenic and mixed origin.

Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region.

Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks.

Polycyclic aromatic hydrocarbons and their nitrated derivatives associated with PM10 from Kraków city during heating season

Polycyclic Aromatic Hydrocarbons (PAHs), their nitro-derivatives (NPAHs) and hundreds of other organic compounds are present in ambient air in gas and particulate form. PAHs and NPAHs originate from diesel and gasoline exhaust emission and other combustion sources. NPAHs are also formed through the nitration of parent PAHs in the atmosphere. Concentrations of PAHs and NPAHs in the particulate matter fraction PM10 collected in the centre of Krakow (27.01.2014 – 17.02.2014) were investigated. The thirteen PAHs and four NPAHs: fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, benzo[a]pyrene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene, benzo[g,h,i]perylene, dibenz[a,h]anthracene, 2-nitrofluorene, 9-nitroanthracene, 3-nitrofluoranthene and 1-nitropyrene were extracted from particulate matter and analysed applying the GC/MS technique. Depending on the compounds the relative recoveries ranged from 72 to 94%. The concentrations of PM10 in the study period ranged between 23.5 and 153.8 μg·m-3. The average concentrations of PAHs and NPAHs ranged from 26.6 to 276.4 ng·m-3 and from 0.6 to 9.1 ng·m-3, respectively. The highest concentrations were observed for benzo[a]pyrene, benzo[a]anthracene, pyrene and fluoranthene. The average concentration of benzo[a]pyrene (BaP), which is a marker for the particle-bound atmospheric PAHs, was 9.5 ng·m-3. The concentrations of 3-nitrofluoranthene and 1-nitropyrene were below the quantification limits of the method (< MQL).

Identification of concentrations and sources of PM2.5-bound PAHs in North China during haze episodes in 2013

An analysis of 12 polycyclic aromatic hydrocarbons (PAHs) in PM2.5 (particulate matter with a diameter smaller than 2.5 microns) samples collected at Yucheng, Shandong, in June 2013 was conducted to determine the concentrations, composition, sources, and associated cancer risk. The results revealed that the average PAH concentration was higher during haze episodes (28.28 ± 8.35 ng m−3) when compared to non-haze episodes (23.68 ± 4.17 ng m−3), and diagnostic ratio and principal component analyses indicate that the predominant sources of PAHs were from fossil fuel and coal combustion, likely from vehicle emissions and industrial sources and biomass burning. Coal combustion and biomass burning contributed significantly more during haze episodes, whereas liquid fossil fuel combustion (e.g. petroleum) was the dominant contributor during the non-haze periods. In addition, back-trajectory calculations revealed that the long-distance transport of air masses from regions with industrial pollution and biomass burning contributed significantly to the concentrations of PAHs in the region. The concentration of high molecular weight PAHs (HMW-PAHs) increased from 62.3 % under non-haze conditions to 67.9 % during the haze periods. The benzo[a]pyrene-equivalent carcinogenic potency value during haze episodes was higher (7.09 ng m−3) than that during non-haze (5.64 ng m−3) periods and adults over 30 years old in the Shandong province are at an increased risk of cancer from PAHs.

Atmospheric levels and health risk of polycyclic aromatic hydrocarbons (PAHs) bound to PM2.5 in Guangzhou, China

The polycyclic aromatic hydrocarbons (PAHs) in PM2.5 contribute significantly to health risk. The objectives of this study were to assess the occurrence and variation in the concentrations and sources of PM2.5-bound PAHs sampled from the atmosphere of a typical southeastern Chinese city (Guangzhou) from June 2012 to May 2013, with the potential risks being investigated. The annual average concentration of PM2.5 was 64.88μgm−3. The annual average concentration of PAHs in PM2.5 was 33.89ngm−3. Benzo(a)pyrene (BaP) was found to be the predominant PAH in all PM2.5 samples throughout the year, constituting approximately 8.78% of the total PAH content. The significant meteorological parameters for most of the PAHs were sunshine time, air pressure, and humidity, together representing 10.7–52.4% of the variance in atmospheric PAH concentrations. Motor-vehicle exhaust and coal combustion were probably the main sources of PAHs in PM2.5 in Guangzhou. The average inhalation cancer risk (ICR) for a lifetime of 70years was 5.98×10−4 (ranging from 8.39×10−5 to 1.95×10−3).

Characterization and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in urban atmospheric Particulate of Tehran, Iran.

In this study, atmospheric concentrations of particulate-bound polycyclic aromatic hydrocarbons (PAHs) in Tehran megacity were determined to investigate the concentration, distribution, and sources of PAHs in PM10. The health risk from exposure to airborne BaPeq through inhalation pathway was also assessed. Toxic equivalency factors (TEFs) approach was used for quantitative risk estimate, and incremental lifetime cancer risk (ILCR) was calculated. PM10 samples were collected at ten sampling locations during the summer 2013 and winter 2014 by using two independent methods of field sampling. The PM10 concentration in winter (89.55 ± 15.56μgm(-3)) was 1.19 times higher than that in summer (75.42 ± 14.93μgm(-3)). Sixteen PAHs were measured with the total average concentrations of PAHs ranged from 56.98 ± 15.91 to 110.35 ± 57.31ngm(-3) in summer and from 125.87 ± 79.02 to 171.25 ± 73.94ngm(-3) in winter which were much higher than concentrations measured in most similar studies conducted around the world. Molecular diagnostic ratios were used to identify PAH emission sources. The results indicated that gasoline-driven vehicles are the major sources of PAHs in the study area. Risk analysis showed that the mean and 90% probability estimated inhalation ILCRs were 7.85 × 10(-6) and 16.78 × 10(-6), respectively. Results of a sensitivity analysis indicated that BaP concentration and cancer slope factor (CSF) contributed most to effect on ILCR mean.

Analysis of Polycyclic Aromatic Hydrocarbon, Toxic Equivalency Factor and Related Carcinogenic Potencies in Roadside Soil within a Developing City of Northern India

Preliminary analysis was performed to assess contamination levels in roadside soils, distribution behavior and human exposure with Polycyclic Aromatic Hydrocarbons (PAHs) during summer, winter, rainy, and autumn during 2013 in one of the developing cities of northern India. The concentration of PAHs was measured at ten different locations (at 1, 2, and 3 m) from roadside soil. Recovery range was 30% and 80% with lower value corresponding to the lower molecular weight PAHs compound. Identification and quantification of PAHs was done by GC-FID. Average PAHs concentration (city average) was found to be 16.53, 4.04, 17.49, and 7.82 μg g−1, during summer, winter, autumn, and the rainy seasons, respectively. Average concentration of low and high carcinogenic PAHs during summer, winter, autumn, and rainy was 5.1 and 31.29, 2.1 and 6.4, 4.74 and 35.08, 3.97 and 12.77μg g−1, respectively. The average ratio of low and high carcinogenic PAHs was found to be 1:6, 1:3, 1:7.6, and 1:3.21 during summer, winter, autumn, and the rainy seasons at most intercepts. Dib(ah)A and B(a)P were the two individual PAHs found in highest concentration during summer, winter, and the rainy seasons, whereas B(a)P and IP were individual PAHs found in highest concentration during autumn. It was also analyzed that high carcinogenic PAHs concentration was quite higher (around 85%) in comparison to low carcinogenic PAHs (around 15%) at most intercepts. This article also deals with the behavior of PAHs at places of average/high population and traffic density intercepts. Five-ringed PAHs were in highest concentration at all intercepts and seasons. Two-tailed T test was applied for authenticity of the data and results. Toxic equivalency factor of B(a)P and Dib(ah)A was maximum as compared to other PAHs.

Subway construction activity influence on polycyclic aromatic hydrocarbons in fine particles: Comparison with a background mountainous site

Intensive construction activities worsened the surrounding atmospheric environment in China. Eighteen polycyclic aromatic hydrocarbons (PAHs) in fine particles (PM2.5) were collected at a subway construction site (SC) of Nanjing and compared with a regional background mountainous site (BM) to examine the influence of anthropogenic activities on concentrations, sources and health risks of PAHs. Average PAH concentrations at SC were higher than BM at a factor of about 5.9. All PAH species at SC were higher than BM, with the SC/BM ratios ranging from 1.3 (NaP) to 10.3 (BaP). PAH profiles differed for the two sites. The SC site had higher mass fractions of PAHs from coal combustion and vehicle emission, while the BM site held higher mass percentages of PAHs from long-range transported wood combustion and industrial activities. Lower temperature at BM may lead to the higher mass percentages of low ring PAHs. Coal combustion, traffic emissions and biomass burning were the common sources for PAHs at both SC and BM. Construction workers were exposed to higher BaPeq concentrations, nearly ten times of the background site and their lifetime cancer risk reached to 0.6 per 1,000,000 exposed worker, owing to the influence of coal combustion, vehicle emission and industrial activities at the surroundings of SC.

PAH Measurements in Air in the Athabasca Oil Sands Region.

Polycyclic aromatic hydrocarbon (PAH) measurements were conducted by Wood Buffalo Environmental Association (WBEA) at four community ambient Air quality Monitoring Stations (AMS) in the Athabasca Oil Sands Region (AOSR) in Northeastern Alberta, Canada. The 2012 and 2013 mean concentrations of a subset of the 22 PAH species were 9.5, 8.4, 8.8, and 32 ng m(-3) at AMS 1 (Fort McKay), AMS 6 (residential Fort McMurray), AMS 7 (downtown Fort McMurray), and AMS 14 (Anzac), respectively. The average PAH concentrations in Fort McKay and Fort McMurray were in the range of rural and semirural areas, but peak values reflect an industrial emission influence. At these stations, PAHs were generally associated with NO, NO2, PM2.5, and SO2, indicating the emissions were from the combustion sources such as industrial stacks, vehicles, residential heating, and forest fires, whereas the PAH concentrations at AMS 14 (∼35 km south of Fort McMurray) were more characteristic of urban areas with a unique pattern: eight of the lower molecular weight PAHs exhibited strong seasonality with higher levels during the warmer months. Enthalpies calculated from Clausius-Clapeyron plots for these eight PAHs suggest that atmospheric emissions were dominated by temperature-dependent processes such as volatilization at warm temperatures. These findings point to the potential importance of localized water-air and/or surface-air transfer on observed PAH concentrations in air.

The Use of Reverse Osmosis in the Removal of PAHs from Municipal Landfill Leachate

Polycyclic aromatic hydrocarbons (PAHs) are relatively well-known organic pollutants and due to their carcinogenic and mutagenic properties their presence in the environment still attracts a lot of attention.According to literature reports and own research, PAHs presence in wastewaters is common. It was confirmed that PAHs are the components of municipal landfill leachate. Membrane techniques are one of the most interesting ways of removing PAHs from leachate.The purpose of this article is to monitor PAHs concentration changes during the membrane (reverse osmosis - RO) leachate treatment processes. In the first stage of testing leachates were filtrated on the sand bed (pre-filtration). After the pre-filtration they were directed to the membrane module for the main filtration.Sixteen PAHs listed by EPA were analyzed. The results with information on PAHs concentration in leachate samples were presented using HPLC with fluorescence detection (FLD). The changes in PAHs concentration were determined in leachate samples before and after pre-filtration as well as after RO. The decrease of PAHs concentration in the samples was observed after these processes. The total concentration of 16 PAHs in raw municipal landfill leachates amounted to 23.64–26.95 μg/L. The research confirmed the high efficiency in removal of PAHs while using a reverse osmosis (59–72%). Including the pre-filtration, the overall level of removed PAHs reached 81–86%. The average PAHs concentration after pre-filtration and RO was in the 4.46–4.99 μg/L range. The municipal landfill leachate with a high concentration of PAHs should be cleaned before it is discharged into the environment.

Concentrations, gas-particle partitioning, and seasonal variations of polycyclic aromatic hydrocarbons at four sites in Turkey.

Ambient air polycyclic aromatic hydrocarbon (PAH) samples were collected at traffic, residential, coastal, and semiurban sites in Bursa, Turkey, between June 2008 and June 2009. For the traffic, residential, coastal, and semiurban sites, the average gas phase total PAH (∑12PAH) concentrations were 113 ± 131, 142 ± 204, 53 ± 73, and 19 ± 34 ng/m(3), respectively, whereas the average particle phase total PAH concentrations were 28 ± 36, 56 ± 85, 24 ± 40, and 11 ± 23 ng/m(3), respectively. Phenanthrene and fluoranthene had the highest concentrations of all of the sampling sites in the gas phase. The PAH concentrations in the heating period were 5-7 times greater than the nonheating period concentrations. Principal component analysis (PCA) was used to investigate the relationship between the levels of PAHs determined in ambient samples and their possible sources. The PCA model shows that coal combustion and vehicle emissions affected PAH emissions. Moreover, the molecular diagnostic ratios indicated that coal-burning and traffic emissions were the dominant PAH sources. The multiple linear regression analysis indicated that the meteorological parameters also affected the ambient PAH concentrations. The sampling site characteristics, meteorological conditions, dispersion, and local sources all affected the concentration levels.

Polycyclic Aromatic Hydrocarbons in the Snowpack and Surface Water in Blackwood Canyon, Lake Tahoe, CA, as Related to Snowmobile Activity

Snowpack in alpine environments may contain appreciable levels of regional pollution acquired through natural processes of wet and dry deposition, as well as from immediate sources such as snowmobile engine exhaust. Understanding the fate and transport of pollutants in alpine environments is a crucial step towards managing emission sources in alpine terrain to mitigate their impacts on natural resources. This study presents detailed chemical analysis for 94 species of polycyclic aromatic hydrocarbons (PAH) in 55 samples of snow and surface water collected in Blackwood Canyon, a tributary to the west shore of Lake Tahoe that is a popular winter recreation area for snowmobile riders. Analyses included toxic and persistent PAH, emitted as products of incomplete combustion and useful for identifying fossil fuel combustion emissions in the environment. Average background snow PAH concentrations were used to estimate background PAH surface loading (μg.m−2). Loadings in excess of the estimated background are mapped and compared with observations of snowmobile activity to determine effects of snowmobile emissions on snow water quality. Loading of heavy PAH, those having three or more aromatic rings, in snow was found to be significantly greater than background loading (α = 5%) where snowmobile tracks cover more than 50% of the snow surface. Loadings were 8–20 times greater than background levels where snowmobile traffic was most concentrated over snow covered roads. PAH were also measured in snow melt and surface water samples in Blackwood Canyon for comparison with snow samples. Flux of PAH (g.day−1) from Blackwood Creek into Lake Tahoe was calculated and compared to estimates of background flux, increasing from 74 g.day−1 to 480 g.day−1 over an 8-day period during spring run-off.