Specific PAHs Research Articles

Distribution assessment and source apportionment of particulate bound-PAHs in indoor air of south Asian precinct using IDW and PMF receptor model: A comprehensivestudy

PAHs have been recognised as a major menace to living-beings as well as environment. Several researchers have extensively claimed regarding death-defying nature of PAHs and its derivatives. However, these studies have only considered the ambient air which is a composition of automobile exhausts, industrial emissions etc. as major source of harmful air pollutants. Indoor air quality (IAQ) is an overlooked area since, although many researchers in recent times have been working on the chemistry and composition of IAQ, yet, source determination and nature of pollutants is still a comprehensive area to be explored. With the above stated objective, the present study emphases on 16 USEPA specified PAHs which are allied with particulate matter. Both PM as well as PAHs are some very common and treacherous chemical contaminant accountable for more than a million death globally. PAHs are organic compound which are either attached to PM of various sizes or can exist in gaseous form. Current work precises the concentration of PAHs associated with fine PM i.e., PM2.5 in indoor environment of south Asian precinct, further, using receptor modelling technique for determination indoor sources responsible for the emanation of specific PAHs. The toxicity equivalent quotient i.e., TEQ evaluated in the study demonstrations that the highest toxicity among all PAHs is exhibited by BaP followed by InP, BKF, BbF. Seasonal variations in the concentration of PAHs and their respective sources were also established using PMF models, which depicted the domination of 3-ring PAHs in winter with 42% contribution in outdoors, whereas, four-ring PAHs dominion in indoors. Similarly, in summer two-ring accounted for 35% in outdoors, and three-ring PAHs contributed highest with 26.8% in indoors. In monsoon PAHs with two-ring contributed highest with 45.2% in outdoors, whereas, 2-ring PAHs contributed 38.3% in indoors. Also, IDW mapping and molecular diagnostic ratio were assessed for an intense study on distribution of PAHs in the locality and the source apportionment purpose respectively. To the best of our knowledge, the study is first of its kind in this part of the world where, majority of the countries are either developing or under-developed and hence at greater risk to the noxious effects which are often overlooked. The study will provide a clear picture regarding the indoor sources of the PAHs and further help the further professionals to build a credible and pragmatic mitigation technique accordingly.

The concentration and probabilistic health risk assessment attribute to PAHs in indoor air of Hormozgan aluminum plant, Iran

ABSTRACT We measured PAHs concentrations to understand the potential short and long-term health risks to workers. In the anode cooking area, the lowest and highest concentrations of PAHs were found for DahA (dibenzo[a,h]anthracene) at 0.373 ± 0.326 µg/m3 and Chry (chrysene) at 1.923 ± 1.258 µg/m3, respectively. In the anode-making area, these concentrations were higher, with DahA at 0.435 ± 0.221 µg/m3 and Chry peaking at 3.841 ± 1.702 µg/m3. Risk assessment based on these concentrations indicates a hierarchical order of individual PAHs risks in the anode cooking area, led by BaP (benzo[a]pyrene), followed by other specific PAHs compounds. The total hazard quotient (THQ) for PAH exposure in both anode-making and cooking areas significantly exceeds the threshold for considered cancer risk, emphasizing the considerable danger to workers. This study underscores the urgent need to mitigate exposure to PAHs in industrial settings to protect worker health from the carcinogenic risks of such hazardous compounds.

Concentration and Distribution of Specific Siloxanes (D5 and D6) and PAHs in the Anacostia and Potomac Rivers, USA

The waterways adjacent to Washington DC, USA have a history of contamination from heavy metals, nutrients, pesticides, and industrial chemicals. Among the chemicals of concern are PAHs, which are a historical contaminant but also have modern pyrogenic and petrogenic sources in the area’s waterways. Another group of contaminants that are of emerging interest are siloxanes (silicones), which are widely used as lubricants, sealants, and cosmetics. Some lower-molecular-weight siloxanes are regulated by the EU in recognition of harm to aquatic life, but there are no restrictions in the United States. In fact, studies examining water pollutants do not typically test for siloxanes. Here, we present the concentrations of specific PAHs and siloxanes from surface sediments in the Potomac and Anacostia Rivers (including the Anacostia’s tributaries) collected between 2018 and 2023. Both D5 (decamethylcyclopentasiloxane) and D6 (dodecamethylcyclohexasiloxane) were found in most locations, with concentrations averaging 0.13 and 0.006 mg/g (dry mass), respectively. Pyrene, fluoranthene, bibenzyl, and phenanthrene were also found in the Anacostia and some of its tributaries, with concentrations increasing downstream. In the Potomac, concentrations were generally lower than those observed in the Anacostia. Based on ratios of pyrene to fluoranthene + pyrene, the likely source of PAHs was petrogenic.

Performance of industrial drying and soybean grains quality

Thus, the objective of this work was to evaluate the performance of industrial drying and the quality of soybean grains using a direct-fire furnace automatically fed by wood chips. To represent the grains before drying, four samples were collected together with the sampling of the loads in the trucks carried out to classify the product in the storage unit. At drying, performance evaluations and specific energy consumption were carried out. The grains were evaluated for moisture content, germination, electrical conductivity, apparent specific mass, color, acidity index, and PAHs. Drying showed an average efficiency of 75.50%. The average chip consumption was 0.4403 kg of chip/kg of evaporated water. The specific energy consumption was 8,099.50 kJ/kg of evaporated water. The grains showed differences after drying in the characteristics of germination, electrical conductivity, and chroma. Six PAHs were detected in the samples before drying: (B(a)A, Chr, 5 MC, B(j)F, Dib(ai)P, and IcdP). After drying, in addition to the PAHs obtained before drying, five more were detected (B(b)F, B(k)F, B(a)P, Dib(al)P, and Dib(ah)A). Mean PAH concentrations were higher than the maximum values ​​allowed by European Union legislation.

Longitudinal Study on the Association between Ambient Polycyclic Aromatic Hydrocarbons and Nasal Symptoms in Adult Japanese

The relationship between exposure to polycyclic aromatic hydrocarbons and nasal symptoms currently remains unclear. Therefore, we herein examine this relationship in 51 adults living in Ishikawa prefecture, Japan, and conducted a 2 month follow-up survey on these participants. All participants were asked to record daily nasal symptoms in an allergy diary during the study period between 1 April to 31 May 2020. We collected air pollutant samples during the study period and determined the concentrations of PAHs and total suspended particulates by high-performance liquid chromatography. Sulfur dioxide and nitrogen dioxide concentrations were obtained through the Atmospheric Environmental Regional Observation System. We used generalized estimating equations to analyze the association between pollutant and nasal symptoms. After adjustment for confounding factors, the B values of fluoranthene, pyrene, and Benzo[k]fluoranthene were 2.389 (p = 0.026), 3.744 (p = 0.022) and 9.604 (p = 0.041), respectively, with a one-day lag. In contrast, the B value of indeno[1,2,3-cd]pyrene was −6.664 (p = 0.013) with no lag. Collectively, these results suggest ambient PAHs such as Flt, Pyr, and BkF were associated with nasal symptoms in adults. Further studies are needed to elucidate the mechanisms contributing to the relationships between specific PAHs and nasal symptoms.

Association between Cough and Ambient Polycyclic Aromatic Hydrocarbons in Patients with Chronic Cough: An Observational Study in Two Regions of Japan

Ambient polycyclic aromatic hydrocarbons’ (PAHs) specific components are likely involved in respiratory disease development and exacerbation in children and adults. Airborne PAH exposure’s effects on cough symptoms in children and adults with chronic coughs in Kanazawa and Fukuoka, Japan, were investigated in this longitudinal study. A total of 98 patients with chronic coughs were enrolled and followed up between 1 April and 31 May 2020. The enrolled patients were non-smoking adults and children aged 3–83 years. Cough diaries were used to record and collect daily cough symptoms. High-performance liquid chromatography coupled with a fluorescence detector was used to determine the particulate PAH content in daily total suspended particles collected on quartz fiber filters. Ambient concentrations of fine particulate matter, nitrogen dioxide, and sulfur dioxide were obtained from local monitoring sites. Generalized estimated equations were used to estimate the association between daily PAHs and cough symptoms. Among nine PAHs measured, benz[a]anthracene (BaA) was significantly associated with cough symptoms for both lag4 and lag5 PAH exposure. These findings suggest that airborne specific PAHs, especially BaA, affect cough symptoms in children and adults with chronic cough. Further studies are needed to develop effective measures to prevent respiratory diseases against specific PAHs.

Assessment of the impact of reforestation on soil, riparian sediment and river water quality based on polyaromatic hydrocarbon pollutants

This study aimed to assess the impact of the eThekwini Municipality reforestation project on the quality of the soil within the reforestation sites, and water from the nearby rivers (White and Black Mhlasini Rivers) situated at the reforested Buffelsdraai area in KwaZulu-Natal, South Africa. This was the first evaluation of the effect of reforestation on the reduction of selected organic pollutants to be conducted in this area. The sixteen polyaromatic hydrocarbons analysed are on the Environmental Protection Agency (EPA) list of priority pollutants. The soil and sediment samples were extracted using ultrasonication, and liquid-liquid extraction was utilised for the water samples. Gas chromatography mass spectrometry (GCMS) was used to analyze the PAHs. PAH recoveries ranged between 60 and 110%. The PAH LOD values were between 0.30 and 0.69 μg g−1 and LOQ values ranged between 0.99 and 1.9 μg g−1. The total PAH concentrations determined were between 4.258 and 6.426 μg g−1 in the soil samples, 2.210–13.900 μg g−1 in sediment, and 6.360–85.468 ng L−1 in river water. A comparison between all samples and their respective control, showed that reforestation is potentially reducing the concentration of PAH pollutants. The concentration of pollutants was determined to be lower within the reforestation boundaries and higher outside the reforestation boundary. The total concentration for specific PAHs was above the threshold value for most sampling sites according to Canadian environmental guidelines.

The Shahejie Formation in the Dongpu Depression, Bohai Bay Basin, China: Geochemical investigation of the origin, deposition and preservation of organic matter in a saline lacustrine environment during the Middle Eocene

The Eocene Shahejie Formation in the Bohai Bay, Eastern China is known to contain important petroleum source rocks. Here, a new, large set of geochemical, petrographical and mineralogical data obtained on 41 samples from 9 wells within the North Dongpu Depression is presented in order to investigate organic matter precursor material, thermal maturity as well as paleoenvironment during deposition of the Es3U, Es3L, Es3M and Es4U members within the Eocene Shahejie Formation. These shales and marlstones from the four sub-members show low to moderate TOC contents (up to 5%) with highest values in the Es3U member; quartz content is at about 10% and carbonate content is variable, partly reaching more than 40%. A range of different maturity parameters was determined indicating early mature to peak oil mature stages, and maturity increase with burial depth. Throughout, alginite is the predominant maceral, whereas both vitrinite and inertinite are rare. Hydrogen index values are highly variable, ranging from about 100 to 700. Distinctly different biomarker assemblages indicate variable depositional environments and organic matter inputs between the four intervals. The Eocene Shahejie shales and marlstones in the study area were deposited under episodic photic zone anoxia as revealed by the presence of aryl isoprenoids. Bottom water conditions were anoxic during most of the time, except for Es3M, as indicated by several parameters, e.g. low pristane/phytane ratios. In north Dongpu Depression Es4U displays a fairly uniform biomarker composition, which indicates relatively stable hypersaline lake conditions with a shallow chemocline based on the high Gammacerane Index > 0.6 and abundant aryl isoprenoids. Water salinity changed during deposition of Es3L according to variable C24 tetracyclic terpanes related parameters and evaporite minerals content. The aquatic algal organisms, i.e. haptophyte algae, diatoms and bryophytes which are reflected by abundant nC37–39 alkanes, a variable sterane pattern and other biomarkers, were flourishing during Es3L. Additionally, specific PAHs, i.e. retene, cadalene, fluoranthene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene also have been identified in small concentration in Es3L, which may be attributed to limited terrigenous organic matter input. Es3M was deposited in a normal lacustrine environment under rather low salinity conditions with substantial input of organic matter derived from algae. During Es3U, saline lake conditions were re-established accompanied by input of both algal and microbial organic matter, especially cyanobacteria as deduced from MMAs and 2α-MeHs, methanogens as deduced from abnormally abundant phytane, PMI, squalane, and methanotrophs from 3β-MeHs.

Phototoxic effects of PAH and UVA exposure on molecular responses and developmental success in coral larvae

Exposure to polycyclic aromatic carbons (PAHs) poses a growing risk to coral reefs due to increasing shipping and petroleum extraction in tropical waters. Damaging effects of specific PAHs can be further enhanced by the presence of ultraviolet radiation, known as phototoxicity. We tested phototoxic effects of the PAHs anthracene and phenanthrene on larvae of the scleractinian coral Acropora tenuis in the presence and absence of UVA (320–400 nm). Activity of superoxide dismutase (SOD) enzyme was reduced by anthracene while phenanthrene and UVA exposure did not have any effect. Gene expression of MnSod remained constant across all treatments. The genes Catalase, Hsp70 and Hsp90 showed increased expression levels in larvae exposed to anthracene, but not phenanthrene. Gene expression of p53 was upregulated in the presence of UVA, but downregulated when exposed to PAHs. The influence on stress-related biochemical pathways and gene expresson in A. tenuis larvae was considerably greater for anthracene than phenanthrene, and UVA-induced phototoxicity was only evident for anthracene. The combined effects of UVA and PAH exposure on larval survival and metamorphosis paralleled the sub-lethal stress responses, clearly highlighting the interaction of UVA on anthracene toxicity and ultimately the coral’s development.

The distribution characteristics of polycyclic aromatic hydrocarbons in typical water system of North China

The temporal and spatial distribution of PAHs in surface-water from the typical rivers of North China was investigated. PAHs in typical rivers ranged from n.d. to 1.98 ng/L. LMW PAHs (2 and 3-ring) were abundant in surface water with high detection frequencies in Beisanhe River, while HMW PAHs (4 and 6-ring) were abundant in Luanhe River. Specific PAHs with its ratios were measured in order to deduce the possible sources of PAHs contaminant. The results indicate that the PAHs were from combustion processes in Beisanhe River, while PAHs were from petroleum products in Luanhe River.

Organic and inorganic priority substances in sediments of Ludaš Lake, a cross-border natural resource on the Ramsar list.

For the first time, long-term monitoring (from 2002 to 2014) was carried out of surface sediments in Ludaš Lake, a Ramsar site in northern Serbia. Organic (16 EPA PAHs, mineral oils, selected pesticides and polychlorinated biphenyls (PCBs)) and inorganic substances (eight heavy metals: Ni, Zn, Cd, Cr, Cu, Pb, As and Hg) were continually investigated. Dibenzo[a,h]anthracene (DahA) and fluorene (Flo) were found at levels indicative of causing adverse effects to biota. Diagnostic ratios of specific PAHs were dominated by high molecular weight components, particularly DahA, which contributed 81.78% of the total high carcinogens, benzo[b]fluoranthene (BbF) and Flo. Potential ecological risk factors (ERi) and the high relative standard deviations (RSD) obtained (up to 245%) for the parameters monitored confirm the high periodical anthropogenic impact from industry, municipal wastewater and agriculture. The highest concentration of inorganic pollution found was for Cd (440-831mg/kg) at all sites, Cu (439mg/kg) in the eastern part of the lake and Cu (388mg/kg) and Hg (771mg/kg) in the northern part of the lake. Based on factor analysis of principal component analysis (PCA/FA), As and phenanthrene (Phe) had significant loadings (0.808 and 0.907, respectively). This association of As with organic anthropogenic sources was also confirmed with the sum of PAHs, pyrene (Pyr) and mineral oil by 3D factor plot, corroborating the theory of As mobilization from metal-reducing microbes as organic (methylated) forms, accelerated by phenanthrene. According to EU national and regional data results, this research suggests that Cu, As, dibenzo[a,h]anthracene and Flo should be added to the list of priority pollutants within the context of applying the European Water Framework Directive (WFD).

The Diagnostics of Laser-Induced Fluorescence (LIF) Spectra of PAHs in Flame with TD-DFT: Special Focus on Five-Membered Ring.

The electronic emission characteristics of 13 gas-phase PAHs, ranging from phenlylacetylene to rubicene, were investigated to diagnose laser-induced fluorescence (LIF) spectra of PAHs in flame by DFT, TD-DFT, and premixed flame modeling methods. It was found that the maximum emission wavelengths of the PAHs with five-membered ring are located in visible region and insensitive to the number of C atoms. However, the fluorescence wavelengths of the PAHs without five-membered rings increase with the number of C atoms due to the reduced HOMO-LUMO gap. In addition, the fluorescence wavelength of the PAHs without five-membered rings with linear arrangement is longer than that of PAHs with nonlinear arrangement. According to the Franck-Condon principle, the vibrationally resolved electronic fluorescence spectra were obtained. The results show that fluorescence bandwidth of the PAHs with five-membered rings is much broader than that of the PAHs without five-membered rings. The concentration of PAHs was calculated by using the premixed flat-flame model with KM2 mechanism. On the basis of the fluorescence bandwidth and the concentration of the PAHs, the potentially fluorescence distribution of PAHs in flame was mapped. One can distinguish the specific PAHs according to the mapped fluorescence distribution of PAHs in this study. It was found that naphthalene should be responsible for the fluorescence located in the 312-340 nm region in the flame. 1-Ethynylnaphthalene is the most possible candidate to emit the fluorescence located in the 360-380 nm region. The fluorescence signals with the wavelength longer than 500 nm are likely emitted by the PAHs with five-membered rings. This study contributes to enhance the selectivity of PAHs in LIF technology, especially in the visible region.

Size distribution and resources of pahs in atmospheric particulate matters in Ho Chi Minh city

In this study, size distribution of 10 PAHs, with 4 – 6 rings in atmospheric particulate matters (PM) at the basement, the roadside and the ambient air in Ho Chi Minh City were measured from 27 December 2010 to 26 January 2011. PM was separated into nine fractions of different sizes as follows: > 9.0, 9.0 – 5.8; 5.8 – 4.7; 4.7 – 3.3, 3.3 – 2.1; 2.1 – 1.1; 1.1 – 0.7, 0.7 – 0.4; và < 0.4 µm. The results showed that the total concentrations of 10 PAHs (total PAHs) varied from 29.7 – 43.7 ng/m3, 37.1 – 45.7 ng/m3, and 8.8 – 18.1 ng/m3, respectively, at the basement site, the roadside site and the ambient air site. Total PAHs were mainly concentrated in particles with aerodynamic diameter smaller than 0.4 μm at the basement and roadside site. On the other hand, total PAHs were mainly concentrated in particles with aerodynamic diameter 0.4 – 0.7 μm at the ambient air site. Generally, the five- and six-ring PAHs were predominately on fine particles (smaller than 2.5 μm aerodynamic diameter) and the 4 – ring PAHs spread-out in both fine and coarse particles (more than 2.5 μm aerodynamic diameter). Diagnostic ratios of specific PAHs were used to characterize the PAH emission sources in the atmosphere. The result of this study indicated that motorcycles and gasoline automobiles are suggested as the main emission sources of PAHs in Ho Chi Minh City and it is necessary to control PAHs concentration in air environment in Ho Chi Minh City.

Distribution of total petroleum hydrocarbons and polycyclic aromatic hy-drocarbons in Musa Bay sediments (northwest of the Persian Gulf)

Sediment samples were collected from the coastal area of the Petrochemical Special Economic Zone of Musa Bay. The samples were analyzed to determine the degree of hydrocarbon contamination and identify the sources of PAHs which were evaluated by employing the ratios of specific PAHs compounds and principal component analysis (PCA). The levels of TPH concentration in the studied area were relatively moderate compared to the world-wide chronically oil-contaminated locations. The concentration of total PAHs was lower than those in other parts of the Musa Bay but approached the NOAA sediment quality guideline value.

Distribution and sources of polycyclic aromatic hydrocarbons in sediments of the Mai Po Inner Deep Bay Ramsar Site in Hong Kong

The concentration of total polycyclic aromatic hydrocarbons (∑PAHs) and the 16 US EPA priority individual PAH compounds were analyzed in surface sediments from the Mai Po Inner Deep Bay, Ramsar Site of Hong Kong from December 2001 to Jun 2005, to investigate the spatial variability of anthropogenic pollutants. ∑PAHs concentrations ranged from 36.5 to 256.3 ng g(-1) dry weight with an average of 148.9 ng g(-1), comparable to other urbanized areas of the world, and there was little difference among different sampling times from December 2001 to June 2005. Based on comparison to the results from earlier study, it appears that a decrease of total PAHs concentration has occurred since 1992. Meanwhile, the concentrations of ∑PAHs were positive correlated with total organic carbon contents except sites F and G, suggesting the characteristics of the sediment influences the distribution and concentration of PAHs. There was relatively a good relationship among the individual PAHs and the compounds of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]pyrene and indeno[cd]pyrene yielded a good correlation (r(2) > 0.5) with total PAHs. Principal component analysis and specific PAHs compound ratios (Phe/Ant vs. Flt/Pyr) indicate the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in the Mai Po Inner Deep Bay Nature Reserve.

Isolation and Characterization of Pyrene Metabolizing Microbial Consortia from the Plant Rhizoplane

Most research on the ecology of PAH degrading bacteria in the rhizosphere has focused on individual strains that grow on specific PAHs. Thus, there are fundamental questions as to importance of microbial consortia for PAH degradation in the plant rhizosphere. The study reported here characterized cultivable pyrene degrading rhizoplane microbial communities from two different plant species using a root printing technique on agar plates. Colonies were revealed by formation of clearing zones on medium containing a thin film of pyrene on the surface of a mineral nutrient agar. Prints of the rhizoplane colonies were obtained from roots of Melilotus officinalis (sweet yellow clover) and Andropogon gerardii (big bluestem) plants. Phylogenetic characterizations of selected pyrene degrading colonies were assessed by PCR-DGGE and DNA sequencing. Results showed that different populations of cultivable pyrene degraders were obtained from representative consortia that were examined. Many of the PAH degrading consortia consisted of mixtures of bacterial species that were unable to degrade pyrene by themselves. While this study focused on culturable PAH degraders, the results suggest that pyrene degradation in the rhizosphere commonly involves the activity of bacterial consortia in which various species of bacteria interact to achieve PAH degradation.

A search for interstellar anthracene towards the Perseus anomalous microwave emission region

We report the discovery of a new broad interstellar (or circumstellar) band at 7088.8 +- 2.0 \AA coincident to within the measurement uncertainties with the strongest band of the anthracene cation (C$_{14}$H$_{10}$$^+$) as measured in gas-phase laboratory spectroscopy at low temperatures (Sukhorukov et al.2004). The band is detected in the line of sight of star Cernis 52, a likely member of the very young star cluster IC 348, and is probably associated with cold absorbing material in a intervening molecular cloud of the Perseus star forming region where various experiments have recently detected anomalous microwave emission. From the measured intensity and available oscillator strength we find a column density of N$_{an^+}$= 1.1(+-0.4) x 10$^{13}$ cm$^{-2}$ implying that ~0.008% of the carbon in the cloud could be in the form of C$_{14}$H$_{10}$$^+$. A similar abundance has been recently claimed for the naphthalene cation (Iglesias-Groth et al. 2008) in this cloud. This is the first location outside the Solar System where specific PAHs are identified. We report observations of interstellar lines of CH and CH$^+$ that support a rather high column density for these species and for molecular hydrogen. The strength ratio of the two prominent diffuse interstellar bands at 5780 and 5797 \AA suggests the presence of a ``zeta'' type cloud in the line of sight (consistent with steep far-UV extinction and high molecular content). The presence of PAH cations and other related hydrogenated carbon molecules which are likely to occur in this type of clouds reinforce the suggestion that electric dipole radiation from fast spinning PAHs is responsible of the anomalous microwave emission detected toward Perseus.

CCQM-K50: Polycyclic aromatic hydrocarbons (PAHs) in soil/particulate matter

There are numerous Calibration and Measurement Capability Claims (CMCs) on PAH analysis in various matrices published in the BIPM key comparison database, Appendix C. By July 2007 such CMCs were released in Category 10 Biological fluids and materials, Subcategory 10.4 Tissues, Category 11 Food, Subcategory 11.2 Contaminants and Category 13 Sediments, soils, ores and particulates, Subcategories 13.1 Sediments, 13.2 Soils and 13.4 Particulates. CCQM comparisons are needed to underpin these claims.A pilot study CCQM-P69 'PAHs in soil' was successfully conducted in 2004. After review of the results at the OAWG meeting in September 2005 it was decided to proceed with a key comparison and a concurrent second pilot study CCQM-K50/P69.1. CENAM and BAM agreed to coordinate the intercomparison. The measurand of the study was specified as amount of specific PAHs in solid matrices as extracted under exhaustive extraction conditions. As for the preceding pilot study and two studies for PAHs in solution (CCQM-P31a and CCQM-K38), five target analytes, phenanthrene, fluoranthene, benz[a]anthracene, benzo[a]pyrene and benzo[ghi]perylene, were selected as representative of the measurement of individual compounds.The CCQM-K50 study utilized a soil sample from BAM and an air particulate sample from NIST. Both materials were naturally contaminated, not enriched or spiked. The mass fraction of target analytes in the samples ranged from 2 mg/kg to 15 mg/kg. NIST SRM 1649a Urban Dust was provided as a control material. Participants were requested to determine the mass fraction of the selected PAHs on a dry mass basis and submit a complete uncertainty budget for their measurements.Ten NMIs participated in the study. All participants applied Soxhlet or Accelerated Solvent extraction (ASE) and GC-MS with either deuterated or 13C labelled internal standards. Results demonstrate a good level of equivalence in capabilities of the participating NMIs to identify and measure PAHs in highly contaminated environmental samples. With a few exceptions, data agree within the range ±5% from the Key Comparison Reference Value (KCRV) for the soil and ±10% from the KCRV for the particulate. Relative expanded uncertainties of the KCRV range from 2% to 5% for the soil and from 4% to 13% for the particulate matter. The KCRV was agreed upon during the OAWG meeting in November 2008 as the arithmetic mean of participants' results. Data of laboratories who did not take part in the preceding pilot study or whose results were not fully traceable to an NMI were excluded from the calculation of KCRVs. Degree of equivalence statements were given for all participants.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Structure–mutagenicity relationships and energies of 1-, and 2-nitrotriphenylenes

The isomers 1- and 2-nitrotriphenylene are present in respirable matter, in combustion and diesel exhaust particulates, and exhibit mutagenic and carcinogenic properties. The structural and electronic properties of triphenylene, 1-, and 2-nitrotriphenylene were investigated with the density functional B3LYP calculations using the 6-311 + G∗∗ basis set. The geometrical bond length agreements were noted between the calculated and experimental geometry for triphenylene (TRP), and predictions of the structural data for 1- and 2-nitrotriphenylene are made in the absence of experimental crystal structures. The geometrical distortions of the triphenylene structure upon nitro group substitution, and structural–mutagenicity relationships of this important class of polycyclic aromatic hydrocarbons are discussed. The energy and molecular orbital energies (E LUMO) were also investigated and found to yield predictive electrophilic reactivity of the isomers. The study of the structure-mutagenic relationships of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) is important in gaining insights into reasons underlying the differential mutagenic potencies of isomers of specific PAHs.

Determination (monitoring) of PAHs in surface waters: why an operationally defined procedure is needed

The results of interlaboratory studies on the determination of selected PAHs in samples of pure water and water containing suspended matter are presented and discussed in this study. Determinations were performed by independent analytical laboratories which used different sample-preparation procedures, i.e. liquid-liquid extraction and solid-phase extraction with columns and speedisks. The study indicates that the results of PAHs determination depend on the type of isolation technique and the final determination procedure used by a given laboratory. Differences among the determined concentrations of specific PAHs reached 700%. In this work it has been shown that modern analysis does not offer isolation techniques for PAHs which would secure their speciation in the aquatic environment.