Volatilization Loss of 6 PAHs with 2–4 Rings Related to Coal Extracts

ABSTRACT

With 3 different bottles, the volatilities of 6 polycyclic aromatic hydrocarbons (PAHs), namely, acenaphthylene, acenaphthene, fluorene, phenanthrene, fluoranthene and pyrene, which were used as model compounds of coal here, had been measured by using gas chromatography/mass spectrometer (GC/MS). The results indicate that although these PAHs have a high boiling point (BP), some PAHs such as acenaphthylene and acenaphthene can be lost rapidly through volatilizing. Even pyrene, having a BP as high as 404°C, can also be lost by volatilizing for a longer period, such as 4 days or more. The volatilization loss of the PAHs is also related to the container. PAHs in wide-mouthed bottles will volatilize faster than in narrow-mouthed bottles. The volatilization loss of the PAHs and other compounds may lead to incorrect results in quantitatively analyzing them in coal extraction, if coal extracts are dried. So, the coal extracts by organic solvents should not be dried before measuring by GC/MS.     

Influence of Sampling Conditions on Solid-Phase Microextraction for the Extraction of Gaseous Polycyclic Aromatic Hydrocarbons

A study was done in order to determine how the sampling conditions can influence the quantitative measure of PAHs in air, done with a solid-phase microextraction device. The PAHs studied were naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene. A comparison between static and dynamic samplings and a plan of experiments were done to study the influence of the gaseous flow, the exposure time, and the number of PAHs in sample, on the mass trapped on the fiber. Then, the performances of PDMS 100 w m and 7 w m fibers for the extraction of PAHs in air were compared. The mass trapped by the fiber, the equilibrium time, the reproducibility, and the performances of the fiber in a dynamic sampling were also tested and compared.     

Polycyclic aromatic hydrocarbons in coke-plant wastewater

The content of polycyclic aromatic compounds—including the strong carcinogens benz[a]pyrene and dibenz[a,h]anthracene—in coke-plant wastewater is investigated. Biochemical purification permits the removal of the following polycyclic aromatic compounds: naphthalene, acenaphthylene, fluorene, acenaphthene, phenanthrene, anthracene, fluoranthene, pyrene, and benz[k]fluoranthene (79.6–99.9% removal); and benz[a]pyrene (65.7% removal). By contrast, biochemical treatment increases the content of the following compounds in the wastewater: benz[b]fluoranthene, benz[g,h,i]perylene, and indeno[1,2,3-cd]pyrene.     

Contamination of Soil by Polycyclic Aromatic Hydrocarbons in Some Urban Areas

The contamination by 16 polycyclic aromatic hydrocarbons (PAHs) in surface soils, sampled at a 0-5 cm depth in the urban areas of Tallinn, Helsinki, Vilnius, Chicago, London is reported. All samples were analyzed using the same protocol. The median concentrations ( w g/kg) were found to be 117, 539, 127, 3,263, 1,728 for pyrene; 62, 236, 43, 1,634, 1,652 for benzo[ a ]pyrene; 86, 304, 92, 2,295, 2,068 for benzo[ a ]pyrene toxic equivalents, calculated using the benzo[ a ]pyrene toxic equivalency factors; 467, 1,471, 392, 8,981, 6,837 for a total of seven probable human carcinogenic PAHs: benzo[ a ]anthracene, chrysene, benzo[ b ]fluoranthene, benzo[ k ]fluoranthene, benzo[ a ]pyrene, dibenz[ ah ]anthracene, indeno[1,2,3- cd ]pyrene; 911, 2,941, 672, 16,183, 13,718 for the total of 16 PAHs, recommended by the U.S. Environmental Protection Agency: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[ a ]anthracene, chrysene, benzo[ b ]fluoranthene, benzo[ k ]fluoranthene, benzo[ a ]pyrene, dibenz[ ah ]anthracene, benzo[ ghi ]perylene, indeno[1,2,3- cd ]pyrene in Tallinn ( n = 3), Helsinki ( n = 3), Vilnius ( n = 15), Chicago ( n = 4), London ( n = 3), respectively. The size of the population is a statistically significant factor in urban soil contamination by high-molecular-mass PAHs.     

POLYCYCLIC AROMATIC HYDROCARBONS ANALYZED IN RAINWATER COLLECTED ON TWO SITES IN EAST OF FRANCE (STRASBOURG AND ERSTEIN)

Polycyclic Aromatic Hydrocarbons (naphtalene, acenaphtene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[j]fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylène, indeno[1,2,3-c,d]pyrene and coronene) have been consecutively analyzed in rainwater sampled in Strasbourg (urban site) and Erstein (rural site) between January 2002 and June 2003 and between April 2002 and June 2003 on a weekly basis respectively. For the sampling of rainwater, a wet-only rainwater sampler was used together with an open collector to take the measurements of precipitation.

PAHs in rainwater were extracted by using SPE cartridges and analyzed by HPLC-fluorescence following a method developed in the laboratory.

Mean concentrations of all PAHs (Σ 16 HAPs) varied between 0.15 and 79.60 ng·L^?1 in Erstein, and between 3.70 and 1596.45 ng·L^?1 in Strasbourg. Naphtalene, phenanthrene, fluoranthene, pyrene, chrysene, benzo[j]fluoranthne and benzo[a]pyrene were the most concentrated PAHs analyzed. Benzo[a]pyrene was frequently detected. Seasonal effects were observed with a maximum of concentrations of PAHs during cold periods. Some spatial influences were also reported. The calculation of some PAH ratios show that diesel exhaust could be the main source of PAHs in rainwater on the two sites.     

Sorption of polycyclic aromatic hydrocarbons from aqueous solution by hexadecyltrimethylammonium bromide modified fibric peat

BACKGROUND: Fibric peat was modified by hexadecyltrimethylammonium bromide (HTAB) to improve its performance in sorption of polycyclic aromatic hydrocarbons (PAHs). The raw fibric peat (P‐R) and surfactant modified peat (P‐HTAB) were characterized by capillary rise test to determine the effect of HTAB on surface hydrophobicity. Effect of contact time was also investigated. Batch sorption data were fitted to the Freundlich model and pseudo‐second‐order model for isotherm and kinetics study. RESULTS: P‐HTAB had a more hydrophobic surface than P‐R. After modification, the sorption coefficients (K_OC) of naphthalene, phenanthrene and pyrene on fibric peat increased from 1590, 29661 and 204171 mL g^?1 to 2006, 52410 and 358569 mL g^?1, respectively; the sorption rate constants of naphthalene, phenanthrene and pyrene increased from 0.00057, 0.00036 and 0.00051 g µg^?1 min^?1 to 0.00062, 0.00140 and 0.00155 g µg^?1 min^?1, respectively. The sorption coefficients of PAHs were positively correlated with the octane‐water partition coefficients of PAHs. CONCLUSIONS: The hydrophobicity of fibric peat was enhanced through modification by HTAB, which resulted in the improved sorption rate and sorption capacity for PAHs. The sorption performance of P‐HTAB reveals that it is an effective biosorbent for PAHs and has potential for treatment of wastewater containing hydrophobic organic contaminants. Copyright © 2010 Society of Chemical Industry     

Extensive Green Roofs as a Means to Capture Polycyclic Aromatic Hydrocarbons

In order to evaluate the ability of green roofs to capture polycyclic aromatic hydrocarbons (PAHs), a study was conducted in México City of 16 PAHs established as priority pollutants by the US Environmental Protection Agency due to their carcinogenic and mutagenic activity. Their concentration was determined in both rainwater and infiltrated water caught by an extensive 10-year-old green roof over 12 rainfall events during a year in the rainy season. The PAHs that were always retained in the green roof were acenaphthene, acenaphthylene, fluorene, phenanthrene, pyrene, fluoranthene, chrysene, and benzo[a]antracene. No prior studies have been conducted in México City that relate to PAHs and extensive green roof.     

Polycyclic Aromatic Hydrocarbons Determination in Grilled Beef and Chicken

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) are principally formed as a result of thermal treatment of food, especially grilling or barbecuing. In the present study, two types of Iranian popular grilled beef and chicken dishes (kebab) were analyzed for toxic PAHs, i.e., naphthalene, fluoranthene, phenanthtrene, anthracene, pyrene, and benzo(a)pyrene applying GC/MS. The differences in PAHs concentrations among grilled beef and chicken (kebab koobide and juje kebab) were found to be significant (p < 0.05), ranging from 0.29 to 21.95 ng·g^?1. Benzo(a)pyrene was found in nearly all samples; the maximum concentration of total PAHs was 21.95 ng·g^?1 found in grilled beef (koobide Khalij fars) and the lowest was 0.29 ng·g^?1 in grilled chicken (juje kebab) of Sahel restaurant.     

Pollicipes pollicipes as a Biomonitor of PAHs Contamination in Seawaters of the Northwest Coast of Portugal

Simple, fast, and economic solid phase microextration–gas chromatography–mass spectrometry (SPME–GC–MS) methods were validated for the determination of 8 United States Environmental Protection Agency priority polycyclic aromatic hydrocarbons (PAHs: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene) in coastal seawaters and soft tissues of goose barnacles Pollicipes pollicipes. Under the optimized conditions, the limits of detection ranged from 0.012 to 1.069 ng L^?1 and 0.002 to 0.061 µg kg^?1 (dry weight basis) for seawaters and soft tissues, respectively. Precision varied between 3.9% and 20.0% for seawaters and between 8.4% and 19.1% for soft tissues, which are acceptable repeatabilities for environmental analyses. Finally, the accuracy of the optimized conditions also showed suitable recoveries, varying between 81.5% and 105.5% in spiked seawater samples and between 88.0% and 103.4% in the standard reference material for organics in mussel tissues (NIST SRM 2977). These methods were applied to a monitoring program performed along the northwest coast of Portugal during four seasons in 2011 in order to assess the levels of these compounds present in coastal waters and in the tissues of goose barnacles, one food resource of high commercial value. The results showed that although the concentrations of PAHs in seawaters and P. pollicipes varied significantly along the coast and between seasons (p < 0.05), in general the concentrations in seawater can be classified as “Class II – Good/Natural Background Concentrations” during the four seasons of 2011. As for the concentrations of PAHs in P. pollicipes, they were positively correlated (p < 0.05) with their concentrations in seawater, indicating that P. pollicipes may be an adequate biomonitor species of PAHs availabilities along the coast of Portugal throughout the year.     

Indoor Polycyclic Aromatic Hydrocarbon Concentration in Central India

The indoor burning of different materials like fuels, incense, mosquito coil, candles etc. results in generation of polycyclic aromatic hydrocarbons (PAHs) in an uncontrolled manner. The PAH, i.e., Benzo(a)pyrene (BaP) is considered as most toxic or carcinogenic and the toxicity of other PAHs is related to this compound. Therefore, the concentration and emission fluxes of polycyclic aromatic hydrocarbons (PAHs) emitted during burning of commonly used indoor materials, i.e., 15 fuels (i.e., biomass (BM), coal (C), cow dung (CD), kerosene (K)), 4 incense (IS) and mosquito coil (MC) in Raipur district, Chhattisgarh, central India is described. The samples were taken in September 2013 in indoor environments and respective smoke emitted were collected using high volume United State of America (USA) air sampler on quartz fiber filters. The concentration of total 13 PAHs (∑PAH₁₃) (i.e., phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)-pyrene, dibenz(ah)anthracene, benzo(ghi) perylene, indeno1,2,3-(cd)pyrene, and coronene) in particulate matter (PM₁₀) in the indoor air during burning of the fuels, IS and MC materials ranged from 367–92052 ng m^?3, 4089–14047 ng m^?3, and 66–103 ng m^?3 with mean values of 7767 ± 11809 ng m^?3, 9977 ± 4137 ng m^?3, and 74 ± 20 ng m^?3, respectively. The mean concentration of the ∑PAH₁₃ present in indoor environment is much higher than the WHO limit value of 1.0 ng m^?3. The sources and toxicities of PAHs are discussed.     

Biosurfactant-Assisted Bioremediation of Polycyclic Aromatic Hydrocarbons (PAHs) in Liquid Culture System and Substrate Interactions

A lipopeptide biosurfactant was produced by the bacterium Pseudomonas aeruginosa strain LBP9 isolated from petroleum-contaminated soil. Phenanthrene, fluoranthene, and pyrene were used as model polycyclic aromatic hydrocarbons (PAHs) to study the effect of the biosurfactant on the biodegradation of mixed and sole substrate PAHs, and examine substrate interactivity effects on their biodegradation in liquid culture. At 400 mg/L amendment of lipopeptide, the solubility of phenanthrene, fluoranthene, and pyrene were increased to 19, 33, and 45 times their aqueous solubility, respectively, and the extent of substrate utilization rate (q_max?) of PAHs was enhanced up to three-fold in the sole substrate studies in comparison to the unamended controls. In the ternary PAH mixture at total concentration of 300 mg/L, with equal parts of each PAH, 77%, 57%, and 33% degradation of phenanthrene, fluoranthene, and pyrene were observed, respectively, at 400 mg/L lipopeptide amendment on day 30 of incubation. Whereas in the sole substrate experiments at 300 mg/L concentration of each PAH and the same level of lipopeptide amendment more than 98% fluoranthene and 76% pyrene were degraded and phenanthrene removal was so rapid that at day 4 of incubation more than 80% was degraded. Biosurfactants at optimum amounts enhanced biodegradation of PAHs. Lipopeptide amendments of 200 mg/L and 400 mg/L were found out to be optimum amounts for statistically significant (p < 0.05) biodegradation of the PAHs in the experiments. However, despite biosurfactant-enhanced bioavailability of the PAHs, biodegradation rate was competitively inhibited in the multisubstrate microcosms.     

Major gaseous and PAH emissions from a fluidized-bed combustor firing rice husk with high combustion efficiency

This experimental work investigated major gaseous (CO and NO_x) and PAH emissions from a 400 kW_th fluidized-bed combustor with a cone-shaped bed (referred to as ‘conical FBC’) firing rice husk with high, over 99%, combustion efficiency. Experimental tests were carried out at the fuel feed rate of 80 kg/h for different values of excess air (EA). As revealed by the experimental results, EA had substantial effects on the axial CO and NO_x concentration profiles and corresponding emissions from the combustor. The concentration (mg/kg-ash) and specific emission (μg/kW h) of twelve polycyclic aromatic hydrocarbons (PAHs), acenaphthylene, fluorene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene and indeno[1,2,3-cd]pyrene, were quantified in this work for different size fractions of ash emitted from the conical FBC firing rice husk at EA = 20.9%. The total PAHs emission was found to be predominant for the coarsest ash particles, due to the effects of a highly developed internal surface in a particle volume. The highest emission was shown by acenaphthylene, 4.1 μg/kW h, when the total yield of PAHs via fly ash was about 10 μg/kW h.     

SAMPLING AND ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBONS IN URBAN AND RURAL ATMOSPHERES: SPATIAL AND GEOGRAPHICAL VARIATIONS OF CONCENTRATIONS

Atmospheric sampling (gas and particles) of PAHs (naphthalene, acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, dibenz[a,h]anthracene, indeno[1,2,3-cd]pyrene, coronene) on XAD-2 resin (20 g) and glass fiber filters respectively, were performed in 2002 by using Digitel DA80 high-volume samplers equipped with a PM10 head. Samplings were performed in Strasbourg (east of France) and its vicinity (Schiltigheim and Erstein). Sites were chosen to be representative of urban (Strasbourg), suburban (Schiltigheim), and rural (Erstein) conditions. Field campaigns were undertaken simultaneously in urban, and suburban, urban and rural sites during spring and autumn during 4 h at a flow rate of 60 m³/h^?1 which gives a total of 240 m³ · h^?1 of air per sample. The period of sampling varied between 06:00 to 10:00, 11:00 to 15:00, 17:00 to 21:00 in order to evaluate a variation of concentration during automobile traffic between urban, suburban, and rural areas. Gas and particle samples were separately Soxhlet extracted for 12 h with a mixture of CH₂Cl₂/n-hexane (50:50 v/v), concentrated to about 1 mL with a rotary evaporator and finally dried under nitrogen. Dry extracts were dissolved in 1 mL of CH₃CN before analysis. Before use, traps were Soxhlet cleaned for 24 h with the same mixture as used for the extraction. Analysis of each extract was performed by reverse phase HPLC, and fluorescence detection and quantification was done with respect to triphenylene used as internal standard. Results shows that automobile traffic seems to be the main source of PAHs in urban areas whatever the period (autumn and spring) while in autumn other sources, especially coming from combustion, influence the atmospheric contamination by PAHs.     

Alkylated hyperbranched polymers as molecular nanosponges for the purification of water from polycyclic aromatic hydrocarbons

A series of hyperbranched polymers functionalized with long aliphatic chains has been prepared and characterized. The property of films prepared from these polymers to encapsulate lipophilic polyaromatic pollutants dissolved in water has been established. The level of pyrene and fluoranthene remaining in water after treatment ranged from 1 to 30 ppb for most of the hyperbranched polymers, while for the relatively more water‐soluble phenanthrene a final concentration of about 50 to 70 ppb could be attained. The inclusion formation constants determined for the polycyclic aromatics were 2.0 × 10⁸–6.3 × 10⁶ M^?1 for pyrene, 1.2 × 10⁷–1.6 × 10⁶ M^?1 for fluoranthene, and 3.8 × 10⁶–4 × 10⁵ M^?1 for phenanthrene. The loading capacities depend on the nature of the polycyclic aromatic compounds and the chemical structure of the parent hyperbranched polymers, ranging from 6 to 31 mg/g of polymer for fluoranthene, 15–54 mg/g for phenanthrene, and 6–35 mg/g for pyrene. Regeneration of the absorbing films was achieved by their treatment with acetonitrile. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2299–2305, 2005     

Evaluation of drum bioreactor performance used for decontamination of soil polluted with polycyclic aromatic hydrocarbons

A laboratory‐scale drum bioreactor system was used to study engineering aspects of soil bioremediation. Polycyclic aromatic hydrocarbons (PAHs) were chosen as contaminants in soil. In the operation of the reactor, different mixing strategies were applied according to the size of soil without separate washing of sand. The effect of the water content of the soil mixture on solid mixing time and phenanthrene degradation rate was of particular interest. At 20% water content, which was below the saturation level, the mixing efficiency of soil and the degradation rate of phenanthrene was lower than those at 30% or 40% water content. Optimal water content was variable according to the soil texture. The drum bioreactor was operated under optimal water content and PAH concentration (fluorene, phenanthrene, anthracene, pyrene) and microbial numbers were measured in each soil phase (sediment and suspension). Over 95% of PAHs with three or four rings (fluorene, phenanthrene, anthracene, pyrene) were degraded at 270 mg kg⁻¹ soil within 20 days. The degradation rate of PAHs in the suspension phase was higher than that in sediment phase. © 1999 Society of Chemical Industry     

Evaluation of polyaromatic hydrocarbon removal from aqueous solutions using activated carbon and hyper‐crosslinked polymer (Macronet MN200)

BACKGROUND: Sorption of polycyclic aromatic hydrocarbons (PAHs) on activated carbon and the Macronet polymeric sorbent MN200 was investigated to determine the effectiveness of each sorbent for removal of pollutants from aqueous solution and their possible use as sorbent materials for groundwater. Experiments were carried out to determine the loading capacities of a family of PAHs (acenaphthene, anthracene, fluoranthene, fluorene, naphthalene and pyrene). RESULTS: Activated carbon was the more effective sorbent, with maximum loadings of PAHs between 90 and 230 g kg^?1, while MN200 resin showed values of 25–160 g kg^?1. Loading isotherms based on the Langmuir, Freundlich and Redlich–Peterson models were determined. The hydrophobic character of the pollutants appeared as an important parameter related to the sorption process. Equilibrium and kinetic parameters were used to determine the retardation factors for each PAH. CONCLUSION: The calculated values for the simulation of barrier thickness using both sorbents, taking into account EU requirements for PAHs in groundwater effluent, were perfectly reasonable as a first estimate. The better kinetic properties of MN200 are evident in lower hydraulic residence times and consequently in a lower barrier thickness. Copyright © 2008 Society of Chemical Industry     

The Effect of Polycyclic Aromatic Hydrocarbons on the Structure of Organotrophic Bacteria and Dehydrogenase Activity in Soil

The objective of this article was to determine the structure of microbial communities and the activity of dehydrogenases in soil samples contaminated with four polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, anthracene, and pyrene, in the amount of 0, 1000, 2000, and 4000 mg kg^?1soil DM. Organic substances—cellulose, sucrose, and compost—were added to the samples in the amount of 0 and 9 g kg^?1soil DM. The experiment was performed in a laboratory on samples of loamy sand. Indices of colony development (CD) and eco-physiological diversity (EP) of organotrophic bacteria, soil resistance (RS), and soil resilience (RL) were calculated. Soil contamination with PAHs differentiated the structure of organotrophic bacteria, and the lowest CD and EP values were noted in soil samples containing pyrene. PAHs inhibited the activity of dehydrogenases, and pyrene exerted the most inhibitory effect on enzyme activity. Dehydrogenase activity was determined mainly by the applied PAH dose, the date of analysis and the type of organic substance added to soil. Low RL values indicate that exposure to PAHs induces long-term changes in dehydrogenase activity.     

The pyrolytic formation of polycyclic aromatic hydrocarbons from benzene,toluene, ethylbenze,e, styrene,phenylacetylene and n-decane in relation to fossil fuels utilization

The yields of groups of Polycyclic Aromatic Hydrocarbons from the pyrolysis of benzene, toluene, ethylbenzene, styrene, phenylacetylene and n-decane in the temperature range of 900–1250 K are reported. At temperatures between 900 and 1100 K the aromatic precursors are converted mainly into non-condensed dimeric compounds, viz. biphenyl in benzene pyrolysis, 1,2-diphenylethane, 1,2-diphenylethylene and 1,2-diphenylacetylene in toluene and ethylbenzene pyrolysis. From n-decane these products are hardly observed. At 1250 K the non-condensed and hydrogenated condensed compounds are thermally unstable. Of the condensed compounds phenanthrene, anthracene and fluorene yields still depend on the type of precursor but acenaphthylene, fluoranthene and pyrene yields are merely a function of temperature. A general mechanism of condensed PAH-formation is derived from the product distribution as a function of temperature. At relatively low temperatures (< 1100 K) radical dimerization is the most important reaction followed by dehydrogenation and dealkylation. A second route is condensation possibly via benzyn intermediates. The anthracene/phenanthrene ratio is discussed in view of the PMO-theory; it is concluded that this ratio is determined both by the stable intermediate precursors of phenanthrene and the instability of anthracene itself.     

Source Apportionment and Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediments from Upper Reach of Huaihe River,China

Fifteen priority PAHs in 16 sediments from upper reach of Huaihe River collected in 2007 were measured. Source apportionment derived from PCA/MLR indicated that the highest contribution to ΣPAHs was from biomass burning (34.1%), followed by coal combustion (29.7%), vehicular emission (25.8%), and coke oven origin (10.4%). Risk assessment for each identified source was quantitatively calculated by combining the benzo[a]pyrene equivalent (BaPE) with estimated source contribution. The results showed that coal combustion posed the highest toxic risk, with BaPE value of 13.1 ng g^?1 dw, and the BaPE values for biomass burning, vehicular emission and coke oven were 5.6 ng g^?1 dw, 7.8 ng g^?1 dw, and 4.1 ng g^?1 dw, respectively. The distributions of contribution for total PAHs burden and BaPE of each identified source showed similar pattern among different sampling sites.     

Ozonation of Polycyclic Aromatic Hydrocarbons in Water Solution

The degradation of three polycyclic aromatic hydrocarbons (PAHs): benzo[a]pyrene (BAP), chrysene (CHR), and fluorene (FLU) in aqueous solution using ozone was investigated. The influence of pH of the reaction mixture, ozone concentration, and the presence of a radical scavenger on the reaction rate was determined. The highest rate of PAHs disappearance was achieved in acidic solutions. The radical scavenger, tert-butanol, effectively inhibited the rate of PAHs destruction. The rate constants of direct reaction of PAHs with ozone were calculated and they were equal to (3.32 ± 0.21) × 10⁴; (1.10 ± 0.15) × 10⁴ and 44.8 ± 1.1 M^?1s^?1 for BAP, CHR, and FLU, respectively. The contributions of direct ozonolysis, and radical reaction to PAHs oxidation in ozonation processes, were evaluated.