Particle-associated Polycyclic Aromatic Hydrocarbons Research Articles

Particle-associated polycyclic aromatic hydrocarbons in the atmospheric environment of Zonguldak, Turkey

Airborne fine (PM 2.5) and coarse (PM 2.5–10) particulate matter was collected from January to December in 2007 in Zonguldak, Turkey using dichotomous Partisol 2025 sampler. Fourteen selected polycyclic aromatic hydrocarbons (PAHs) in particulate matter were determined simultaneously by high-performance liquid chromatography with fluorescence detection (HPLC-FL) and seasonal distributions were examined. The source identification of PAHs in airborne particulates was performed by principal component analysis (PCA) in combination with diagnostic ratios. The predominant PAHs determined in PM 2.5 were pyrene, fluoranthene, benzo[ a]anthracene, chrysene, benzo[ b]fluoranthene and benzo[ a]pyrene. The total concentrations of PAHs were up to 464.0 ng m − 3 in fine and 28.0 ng m − 3 in coarse fraction in winter, whereas in summer times were up to 22.9 and 3.0 ng m − 3 respectively. Approximately 93.3% of total PAHs concentration was determined in PM 2.5 in winter and 84.0% in summer. The concentration levels of PAHs fluctuate significantly within a year with higher means and peak concentrations in the winter compared to that of summer times. Higher benzo( a)pyrene-equivalent (BaPE) concentrations of PAHs were obtained for PM 2.5 especially in winter. The results obtained from PCA in combination with diagnostic ratios revealed that coal combustion and vehicle emissions were the major pollutant sources for both PM 2.5 and PM 2.5–10 associated PAHs in studied area. Two principal components for PM 2.5 and three for PM 2.5–10 were identified and these accounted for 89.4 and 85.2% of the total variance respectively. The emissions from coal combustion were estimated to be the main source of PAHs in the ambient air particulates with contributions of 80.8% of total variance for PM 2.5 and 53.8% for PM 2.5–10.

Determination of Particle-associated Polycyclic Aromatic Hydrocarbons in Urban Air of Beijing by GC/MS

Particle-associated polycyclic aromatic hydrocarbons (PAHs) collected in urban air of Beijing were studied using a gas chromatograph mass spectrometer (GC/MS). The average concentration of particle-associated PAHs measured in this work was in the range from 28.53 to 362.15 ng/m3, which suggested a serious pollution level of PAHs in Beijing. The results also showed that the concentration of PAHs in the winter was distinctly higher than that in summer and spring. Benzo(a)pyrene (BaP) and benzo(a)pyrene-equivalent carcinogenic power (BaPE) were adopted to evaluate the PAHs pollution state at the sampling site. Through some diagnostic ratios, it can be concluded that traffic exhaust, especially vehicles with diesel engines, and domestic coal-burning heaters might have a prominent contribution to the PAHs concentration.

Seasonal and spatial trends of suspended-particle associated polycyclic aromatic hydrocarbons in urban Shizuoka, Japan

We characterized the monthly variations of 21 polycyclic aromatic hydrocarbons (PAHs) associated with suspended particles in the city of Shizuoka, Japan, over 12 months during 2001 and 2002. The fraction of fine particles (less than 2.5 μm diameter (PM2.5)) ranged from 40 to 60% of total suspended particles over the 12 months of the study, and their concentrations ranged from 19.3 to 41.7 μg/m 3. Almost all the PAHs were found in the PM2.5 fraction, in which the summed concentration (∑PAH) of the 21 PAHs ranged from 1.0 to 8.4 ng/m 3. PAH concentrations were elevated in the colder seasons, but the concentrations of the PM2.5 fraction of suspended particles were not. The composition of PAHs associated with PM2.5 changed little during the year of our study, indicating that seasonal sources such as heating have little effect. Factor analysis showed that three factors explain little of the seasonal variations in the sources of PAHs. Contour maps showed high concentrations of indicator PAHs for gasoline and diesel engine sources distributed along major roads and near factories on the outskirts of the city. We concluded that the contribution of vehicle exhausts to particle-associated PAHs is significant not only in the central city, but also in outer areas associated with major ring roads, and suggest that air pollution in outskirts of urban area also is concerned for health risk associated with the exposure.

Increased health risk in Bangkok children exposed to polycyclic aromatic hydrocarbons from traffic-related sources

The aim of this study is to assess potential health risk of exposure to particle-associated polycyclic aromatic hydrocarbons (PAHs) in children living in a megacity with traffic congestion such as Bangkok. The study population comprised 184 Thai schoolboys (aged 8-13 years) attending schools adjacent to high-density traffic areas in Bangkok and schools located in the provincial area of Chonburi. The ambient concentration of total PAHs at roadsides in proximity to the Bangkok schools was 30-fold greater than at roadsides in proximity to the provincial schools (30.39 +/- 5.80 versus 1.50 +/- 0.28 ng/m(3); P < 0.001). Benzo(g,h,i)perylene (BghiP), an indicator of automobile exhaust emission, was the predominant PAH. Personal exposure to total PAHs and the corresponding benzo(a)pyrene (BaP) equivalent concentrations in Bangkok schoolchildren were 3.5-fold higher than in provincial schoolchildren (4.13 +/- 0.21 versus 1.18 +/- 0.09 ng/m(3); P < 0.001 and 1.50 +/- 0.12 versus 0.43 +/- 0.05 ng/m(3); P < 0.001, respectively). The concentration of urinary 1-hydroxypyrene (1-HOP) was significantly higher in Bangkok schoolchildren. Bulky carcinogen-DNA adduct levels in peripheral lymphocytes were also significantly higher (0.45 +/- 0.03 versus 0.09 +/- 0.00 adducts/10(8) nt; P < 0.001). Finally, a significantly higher level of DNA strand breaks and a significantly lower level of DNA repair capacity were observed in Bangkok schoolchildren (P < 0.001). This study indicates that Bangkok schoolchildren exposed to a high level of genotoxic PAHs in ambient air may be more vulnerable to the health impacts associated with the exposure to genotoxic pollutants than children in provincial areas and may have increased health risks for the development of certain diseases such as cancer.

Photolysis of polycyclic aromatic hydrocarbons associated with fly ash particles under simulated sunlight irradiation

Fly ash particle-associated polycyclic aromatic hydrocarbons (PAHs) were produced by combustion of polyvinyl chloride (PVC), wood, high-density polyethylene (HDPE), and polystyrene in a stove. Fly ash particles were deposited on the glass slides (76 mm × 26 mm) placed in the exposure chamber. The concentration of 16 PAHs ranged from 10.1 pg/dm 2 fly ash for acenaphthene to 2348.7 pg/dm 2 fly ash for fluoranthene. Medium to large molecular weight PAH concentrations were much higher compared to low molecular weight PAHs on fly ash. Photolysis of PAHs associated with fly ash particles deposited on glass slides was investigated under simulated sunlight irradiation for about 550 h. Generally, the photolysis rates of the 16 PAHs follow first-order kinetics. Under simulated sunlight containing UV-B, the photolysis of PAHs includes two phases: fast (0–50 h) and slow phase (50–550 h). The photolysis rate constants of PAHs in the initial fast phase were far greater than those in the slow phase. When UV-B was removed from the simulated sunlight irradiation, the photolysis rate constants of PAHs were significantly lower compared to those observed in the fast phase with UV-B exposure, suggesting UV-B radiation could accelerate photolysis of PAHs adsorbed on the fly ash particles. In addition, partial least squares (PLS) analysis models were applied to explain the molecular structural characteristics that affect the PAH photolysis rates. The results suggested that the photolysis rate constants of PAHs decrease with the increasing of molecular weight ( M w), the energy of the lowest unoccupied molecular orbital ( E LUMO), E LUMO + E HOMO, and the standard heat of formation (Δ H f).

Measurement of genotoxic air pollutant exposures in street vendors and school children in and near Bangkok

The effects of air pollution on human health are a great concern, particularly in big cities with severe traffic problems such as Bangkok, Thailand. In this study, exposure to genotoxic compounds in ambient air was studied by analysis of particle-associated polycyclic aromatic hydrocarbons (PAHs) and benzene through direct measurement of concentrations in air as well as through the use of different biomarkers of exposure: urinary 1-hydroxypyrene (1-OHP) for PAHs and urinary t,t-muconic acid ( t,t-MA) for benzene. The study was conducted in various susceptible groups of the population with different occupations in 5 traffic-congested areas of Bangkok, as well as in primary school children. The level of total PAHs on the main roads at various sites ranged from 7.10 to 83.04 ng/m 3, while benzene levels ranged from 16.35 to 49.25 ppb. In contrast, ambient levels in nearby temples, the control sites, ranged from 1.67 to 3.04 ng/m 3 total PAHs and 10.16 to 16.25 ppb benzene. Street vendors selling clothes were exposed to 16.07 ± 1.64 ng/m 3 total PAHs and 21.97 ± 1.50 ppb benzene, levels higher than in monks and nuns residing in nearby temples (5.34 ± 0.65 ng/m 3 total PAHs and 13.69 ± 0.77 ppb benzene). Grilled-meat vendors in the same area were exposed to both total PAHs and benzene at even higher levels, possibly due to additional formation of PAHs during the grilling of meat (34.27 ± 7.02 ng/m 3 total PAHs; 27.49 ± 2.72 ppb benzene). At the end of the workday, urinary 1-OHP levels in street vendors (0.12 and 0.15 μmol/mol creatinine in clothes and grilled-meat vendors, respectively) were significantly higher than in controls (0.04 μmol/mol creatinine; P < 0.01). Afternoon urinary t,t-MA levels in both groups of street vendors (0.12 mg/g creatinine) were also significantly higher than in controls (0.08 mg/g creatinine; P < 0.05). School children from two schools in Bangkok were exposed to total PAHs and benzene at levels of 6.70 ± 0.47 ng/m 3 and 4.71 ± 0.25 ppb, respectively, higher than those to which children living outside the city were exposed (1.25 ± 0.24 ng/m 3 total PAHs; 2.10 ± 0.16 ppb benzene). At the end of the school day, levels of urinary 1-OHP and t,t-MA were significantly higher ( P < 0.001 and P < 0.01, respectively) in Bangkok school children (0.23 μmol/mol creatinine and 0.27 mg/g creatinine, respectively) than in school children from outside Bangkok (0.10 μmol/mol creatinine and 0.08 mg/g creatinine, respectively).

Polycyclic aromatic hydrocarbons in the atmosphere: monitoring, sources, sinks and fate. II: Sinks and fate.

This paper reviews the transformation processes that polycyclic aromatic hydrocarbons (PAHs) undergo in the atmosphere. These processes can take place both in the gas phase and in the particulate/aerosol one. Among the gas-phase processes, the most important ones are the daytime reaction with *OH and the nighttime reaction with *NO3. The relative importance of the two processes depends on the particular PAH molecule. For instance, gaseous naphthalene is mainly removed from the atmosphere upon reaction with *OH, while gaseous phenanthrene is mainly removed by reaction with *NO3. Oxy-, hydroxy-, and nitro-PAHs are the main transformation intermediates. Reaction with ozone and photolysis play a secondary role in the transformation of gaseous PAHs. The particle-associated processes are usually slower than the gas-phase ones, thus the gas-phase PAHs usually have shorter atmospheric lifetimes than those found on particulate. Due to the higher residence time on particulate when compared with the gas phase, direct or assisted photolysis plays a relevant role in the transformation of particle-associated PAHs. Among the other processes taking place in the condensed phase, nitration plays a very important role due to the health impact of nitro-PAHs, some of them being the most powerful mutagens found so far in atmospheric particulate extracts.

Particle-associated polycyclic aromatic hydrocarbons in urban air of Hong Kong

Abstract PM2.5 and PM10 samples were collected at two sampling sites in Hong Kong in wintertime from November 2000 to March 2001 and in summertime from June to August 2001. The concentrations of 16 selected polycyclic aromatic hydrocarbons (PAHs) in aerosols were quantified. Spatial and seasonal variations of PAHs were characterized. The dominated PAHs in PM2.5 and PM10 included benzo[b]fluoranthene, pyrene, fluoranthene, indeno[1,2,3-cd]pyrene and chrysene, accounting for 50–82% of total PAHs. The sum of 16 PAHs in PM2.5 at roadside ranged from 3 to 330 ng/m3, and in PM10 between 5 and 297 ng/m3, whereas at a residential/industrial/commercial site, the total PAHs in PM2.5 was from 0.5 to 122 ng/m3, and 2–269 ng/m3 in PM10. Results indicated that most of the PAHs were in the PM2.5 fraction. Spatial variations were predominantly due to the difference of source strength. For both PM2.5 and PM10, the total PAHs at PU site was higher than that at KT site. The average concentrations of individual PAHs in aerosols at PU site were also higher than that at KT site. Higher winter PAHs concentrations and lower summer concentrations were observed at the two sites. Higher winter PAHs concentrations were mainly caused by local emission sources superimposed by highly polluted air masses from Mainland China. The lower summer PAHs concentrations were likely due to easier dispersion of air pollutants, washout effects and to a lesser extent, photo-degradation and higher percentage in the air in vapor phase. Potential sources of PAHs in aerosols were identified using the diagnostic ratios between PAHs and PCA analysis. At PU site, vehicular emissions were the main contributors of particle-associated PAHs, and stationary combustion sources may also contribute to the particulate PAHs. On the contrary, at the KT site, PAHs in aerosols were predominantly from gasoline and diesel engines.

Atmospheric Deposition of PAHs to a Small Urban Lake, Lake Luhu, Guangzhou

Atmospheric concentrations and deposition fluxes of particle-associated polycyclic aromatic hydrocarbons (PAHs) were measured over a 1-year period (2001-2002) at a small urban lake, Lake Luhu, in Guangzhou, aiming to estimate their atmospheric loadings to the lake. The annual average PAH deposition fluxes was 0.47mg/(m2·a). It was estimated that within a whole year there was approximately 0.1kg of particle-associated PAHs depositing to the lake from atmosphere. Significant seasonal variations of the PAHs deposition fluxes were observed, suggesting that both highly variable atmospheric PAHs concentrations and complex scavenging processes controlled the result. In the whole year, the highest particle deposition fluxes of PAHs were observed in winter and spring and the lowest fluxes were in autumn. Compared the compositions of deposition fluxes of particle-associated PAHs to that of total suspended particle (TSP) in the air, wet deposition contributed the heavyweight PAHs to deposition fluxes, whilst dry deposition along with low temperature would favour the deposition of lightweight PAHs. With the increasing rainfall, the composition of particle-associated PAHs deposit to the urban lake became similar to that of the total suspended particulates (TSP).

Atmospheric gas-particle partitioning of polycyclic aromatic hydrocarbons in high mountain regions of Europe.

Atmospheric concentrations and gas-particle partitioning of polycyclic aromatic hydrocarbons (PAH) have been determined at three remote mountain areas in Europe. Gas-phase mean concentrations of total PAH (20 individual compounds) were very similar at all sites, ranging from 1.3-2.6 ng m(-3) in the Pyrenees (Spain) to 2.7-3.7 ng m(-3) in the Alps (Austria) and Caledonian mountains (Norway). A seasonal variability was observed, with the highest levels found in winter. The seasonal differences were reflected better in the particle-associated PAH, showing the increase of PAH emissions in the colder months and a temperature dependence of the gas-particle partitioning. Significant geographical differences were also observed for particulate PAH, indicating a greater influence of regional sources than in the gas phase. Partitioning of PAH between gas and particulate phases was well-correlated with the subcooled liquid vapor pressure in all samples, but with slopes significantly steeper than the expected value of -1. These steeper slopes may reflect the occurrence of a nonexchangeable PAH fraction in the aerosols, likely associated to the soot carbon phase. Comparison of absorption to organic matter and soot carbon using the octanol-air (Koa) and soot-air (Ksa) partitioning coefficients shows that, despite uncertainties on estimated organic matter and soot carbon contents in the sampled aerosols, Koa underpredicts aerosol PAH concentrations by a factor of 0.6-2 log units. In contrast, predicted and measured high mountain aerosol PAH differ by 0.2-0.6 log units when Ksa is considered. The results point to soot carbon as the main transport medium for the long-range distribution of aerosol-associated PAH.

Characterisation and determination of profiles of polycyclic aromatic hydrocarbons in a traffic tunnel in Gothenburg, Sweden

The concentrations of semi-volatile polycyclic aromatic hydrocarbons (PAHs), hydrocarbons (HCs), particulate matter (PM 1, 2.5 and 10 μm) and total suspended particles (TSPs) were measured in a traffic tunnel in Gothenburg, Sweden. Emission factors (EFs) were also calculated. These variables are assumed to provide good estimates of average vehicle emissions, since all types of vehicle, using all types of fuel, pass through this tunnel. It was shown that the majority of particle-associated PAHs were found on particles with an aerodynamic diameter of <1 μm. The concentrations of PAHs were one order higher in magnitude in air samples from the tunnel than in air samples at two urban locations. However, the PAH profiles of air samples from the tunnel and the urban sites were similar. This was demonstrated using principal component analysis (PCA). Finally, and notably, there was no significant change in the total emissions when the proportion of heavy-duty vehicles (HDVs) increased from 8% to 24%. Previously, diesel vehicles had been found to release larger quantities of PAHs and related substances. Advances in fuel quality, and HDV motor and exhaust system design during the last decade may have contributed to this promising result. However, it was shown, using partial least squares regression to latent structures (PLS), that some of the parameters measured displayed correlations with the proportions of HDVs and light-duty vehicles (LDVs). Concentrations of total HCs, TSPs, dibenzothiopene, phenantrene, anthracene and monomethyl-derivatives of phenantrene and anthracene were all correlated to the proportion of HDVs. The concentrations of naphthalene, some mono- and dimethylnaphthalenes and most large PAHs (with 5–7 fused rings) were correlated to the proportion of LDVs.

Effects of methanol-containing additive on emission characteristics from a heavy-duty diesel engine

This study was aimed to investigate the effect of methanol-containing additive (MCA) on the regulated emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO x ), particulate matter (PM), as well as the unregulated carbon dioxide (CO 2) and polycyclic aromatic hydrocarbons (PAHs) from a diesel engine. The engine was tested on a series of diesel fuels blended with five additive levels (0, 5, 8, 10 and 15% of MCA by volume). Emissions tests were performed under both cold- and hot-start transient heavy-duty federal test procedure (HD-FTP) cycles and two selected steady-state modes. Results show that MCA addition slightly decreases PM emissions but generally increases both THC and CO emissions. Decrease in NO x emissions was found common in all MCA blends. As for unregulated emissions, CO 2 emissions did not change significantly for all MCA blends, while vapor-phase and particle-associated PAHs emissions in high load and transient cycle tests were relatively low compared to the base diesel when either 5 or 8% MCA was used. This may be attributed to the lower PAHs levels in MCA blends. Finally, the particle-associated PAHs emissions also showed trends quite similar to that of the PM emissions in this study.

Exposure to genotoxins present in ambient air in Bangkok, Thailand--particle associated polycyclic aromatic hydrocarbons and biomarkers.

Exposure to genotoxic compounds in ambient air has been studied in Bangkok, Thailand, by analysis of polycyclic aromatic hydrocarbons (PAHs) associated with particles and using different biomarkers of exposure. Eighty-nine male, non-smoking Royal Thai police officers were investigated. The police officers were divided into a high exposure group (traffic police) and low exposure (office duty). Particulate matter was collected using personal pumps (2 l/min) and the eight carcinogenic PAHs were analysed by standard procedures. The traffic police was exposed to a 20-fold higher level of total PAHs than office police (74.25 ng/m3 vs. 3.11; P= 0.001). A two-fold variation was observed between the different police stations. The major PAHs in all groups was benzo[g,h,l]pyrelene. Large inter-individual differences in biomarker levels were observed, but the level of all markers was statistically significantly higher in the traffic police group than in the office group. The level of 1-hydroxypyrene (1-HOP) was 0.181+/-0.078 (range 0.071-0.393) micromol/mol creatinine in the traffic group and 0.173+/-0.151 (P = 0.044) in the office group. The bulky carcinogen DNA-adduct level, determined by P32-post-labelling, was 1.6+/-0.9 (range 0.4-4.3) adducts/10(8) nucleotides in the traffic group and 1.2+/-1.0 (0.2-4.9) in the office group (P = 0.029; Mann-Whitney U-test). The serum PAH-albumin adduct level was 1.76 (0.51-3.07) fmol adducts/microg albumin in the traffic group and 1.35+/-0.77 (0.11-3.45; P = 0.001) in the office group. Lower biomarker levels were observed during the period when the traffic police officers were wearing a simple facemask, indicating that these masks protect against particle-associated PAHs. No statistically significant correlations were observed between biomarker levels and the level of individual PAHs or total PAH. Our data show, that people in Bangkok, who spend most of the day outside air-conditioned offices, are exposed to high levels of genotoxic PAHs. However, for people who spend their working day in offices, the exposure is similar to people living in other metropolitan areas.

Particle-associated polycyclic aromatic hydrocarbons in the atmosphere of Hong Kong

Polycyclic aromatic hydrocarbons (PAHs) in total suspended particulates (TSP) collected at six rural and urban stations in Hong Kong from 1993–1995 using high volume air samplers were identified using GC-MS (gas chromatography-mass spectrometry). The results showed that the PAHs exhibited distinct spatial and seasonal variability. The total PAH content (ΣPAH) in the samples ranged from 0.41 to 48 ng m-3. The unsubstituted analogs are the characteristic products of high temperature combustion processes. The highest average ΣPAH was measured at the street-level station in Mong Kok indicating that vehicles were high PAHs contributors. The rural station at Hok Tsui exhibited the lowest PAH level, however; influences of city plumes could be seen when northerly or northeasterly winds prevailed in the winter. All stations experienced the highest loading of PAHs in autumn and the lowest in summer; the former was 2.8 times greater than the latter. This seasonal variability is due to the Asian monsoon system, precipitation, micrometeorology, and the rate of photodegradation. In summer, Hong Kong experiences relatively clean oceanic air and high rates of precipitation and photodegradation, while upon the onset of the winter monsoon, local air mass is replaced by polluted air streams from the Asian continent. Benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(e)pyrene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene were the dominant species in the samples. The PAH distribution patterns at different stations were similar within each season. However, seasonal variations existed. For example, phenanthrene contributed up to 14% of the total PAH in summer, while the dominance of benzo(b)fluoranthene, benzo(k)fluoranthene was more significant in autumn and winter.

Polycyclic Aromatic Hydrocarbons in the Arctic: Ob and Yenisei Estuaries and Kara Sea Shelf

Suspended matter (SM) and surface sediments were analysed for polycyclic aromatic hydrocarbons (PAH) throughout the Ob and Yenisei River estuaries and in the Kara Sea in order to evaluate the contamination of Arctic shelves by these two major Siberian rivers. PAH concentrations were extremely low, among the lowest measured up to now in the Arctic region. Particle-associated PAH were in many cases non-detectable. A total PAH maximum value of 3·2ngl−1was found in surface waters. In surficial sediments, they spanned a range from 24 to 115ngg−2in the Ob River, from 40 to 131ngg−2in the Yenisei and from 16 to 94ngg−2in the Kara Sea. Compositional features revealed a contribution of detrital material eroded from soils of the drainage basins and inputs from airborne pyrolytic PAH emitted at lower latitudes and from industrial complexes in Siberia. Particulate and sedimentary PAH distributions were highly variable both in type and concentration. The Ob and Yenisei estuaries are geographically large features where hydro-dynamical and sedimentary processes are complex. As a consequence, inhomogeneities—in the form of patch-structures—develop and make it difficult to resolve the fate of riverborne constituents based on ship measurements only. Remote sensing in conjunction with oceanographic observations may provide further guidance to study large river systems.

Relationship between soft bottom macrofauna and polycyclic aromatic hydrocarbons (PAH) from smelter discharge in Norwegian fjords and coastal waters

Data from monitoring surveys were used to test the responses of soft bottom fauna in Norwegian fjords and coastal waters affected by effluents from aluminium and manganese alloy smelters to effluent discharges. Generally, polycyclic aromatic hydrocarbons (PAHs) have been considered the main threat to the biota in the receiving waters. Data from a total of 57 quantitative stations, of which 30 were simultaneously sampled for sedimentary PAHs, were analysed. Canonical Correspondence Analysis (CCA) was used to evaluate species patterns in relation to sediment PAH concentrations and natural environmental variables such as depth, sediment characteristics and riverine input. The PAHs varied from very high concentrations (760 pg g.' total PAH) at the most impacted sites to background levels in reference areas. Despite previous reports of little to no effects of the effluent discharges, the analyses identlf~ed significant species changes along PAH gradients, which could be associated with feeding modes. In particular, a number of carnivorous polychaetes had their dlstnbution ophma In the most affected areas. Based on species statistics calculated by CCA, response functions were fitted for the species on PAH and used to establish a generalised expression of trophic community structure in relation to PAH concentrations. At low PAH levels, the carnivores represented 15 to 20% of the specimens in the communities, but the proportion began to increase from about 10 pg g-' and exceeded 50% at 100 pg g-' total PAH. The fauna1 changes were most evident in shallow waters, possibly reflecting the effects of dissolved PAHs to which the species may react more directly than they do to sedlrnentary particle-associated PAHs.

Effects of Physical Chemistry and Bioturbation by Estuarine Macrofauna on the Transport of Hydrophobic Organic Contaminants in the Benthos

Effects of macrobenthos on hydrophobic organic contaminant (HOC) transport during two seasons characterized by high (summer) and low (winter) bioturbation were studied in the laboratory. HOC burial and loss from microcosms were followed in the presence and absence of macrofauna after the introduction of particle-associated polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) to the sediment−water interface. During summer, HOC burial depths and modeled diffusive losses (DL) increased with compound relative effective diffusivity ( ), consistent with enhanced fluid transport rates due to macrofauna. Although more than 50% of HOC loss was independent of macrofauna, macrofauna-mediated processes had significant effects on the long-term (56 d) removal of the hydrophobic compounds TCB and BaP. A possible mechanism for this effect is direct particle resuspension by macrofauna, which has been shown to enhance loss of materials from our experimental systems. During winter, macrofauna had little effect on HOC burial but may have enhanced HOC retention. Thus, effects of macrofauna-mediated processes depend on HOC physico-chemistry as well as the temporal phasing and duration of contaminant−biota interac tions. Bioturbation has important implications for contaminant fate because macrofauna significantly alter the distributions of HOCs near the sediment−water interface.

Surface Microlayer Enrichment of Polycyclic Aromatic Hydrocarbons in Southern Chesapeake Bay

Dissolved and particle-associated polycyclic aromatic hydrocarbons (PAHs) were measured in the surface microlayer (SM) of the York and Elizabeth River tributaries of Southern Chesapeake Bay throughout 1 year. Particle-associated PAH concentrations in the SM increased nonlinearly with total suspended particulate (TSP) levels, and a much more rapid rise in particulate PAHs with TSP was observed in the Elizabeth River vs the York River SM. The steep rise in particle-associated PAH concentrations along with observed nonequilibrium distributions of PAHs between the dissolved and particle phases in the Elizabeth River SM implies that atmospheric deposition of soot particles may be an important source of PAHs to this urban estuary. A significant relationship between dissolved PAHs and dis solved organic carbon (DOC) was also observed at the York River site, with the more hydrophilic PAHs exhibiting greater increases with DOC. PAHs were significantly enriched in the SM of both sites relative to the subsurface water concentrations. Particle-associated and dissolved phase enrichment factors were strongly influenced by wind speed at the Elizabeth River site; however, only particulate phase enrichment factors were dependent on wind speed at the York River site.

Atmospheric emission of polycyclic aromatic hydrocarbons in sampling areas of the German environmental specimen bank. Method for the precise measurement of gaseous and particle-associated polycyclic aromatic hydrocarbons in the sub-nanogram range using deuterated internal standards

The objective of this study was to determine the impact by polycyclic aromatic hydrocarbons (PAHs) in areas in which samples are regularly taken by the German Environmental Specimen Bank (GESB). A filter combination consisting of a glass fibre and a PU foam filter has been used to completely collect atmospheric pollutants allowing a quantitative extraction of the PAHs collected and a simple cleanup. The mass spectrometric evaluation using deuterated standards resulted in standard deviations of 1–6% for various PAHs detected by this method (extraction + cleanup + MS-SIM) applied to the sub-nanogram range. The repeatability of the method (sampling + analysis) has been checked by taking 5 different samples with 5 different samplers at the same location. The sampling period was 6 h and resulted in variation coefficients of 2.1–10.2%. Real samples were taken in 3 different areas more than 400 km distant from each other (Halle/Leipzig, n=7; Saarland, n=14, Großhansdorf, n=30). Almost identical profiles of the volatile PAHs were recorded in all 3 areas suggesting a long-distance intermix of the atmosphere. However, different profiles of particle-bound PAHs were found in different sampling areas indicating that they are suitable to characterise local emission rates and possibly also emission sources.

Concentrations of particulate airborne polycyclic aromatic hydrocarbons and metals collected in Lahore, Pakistan

Hi-vol air sampling equipment was run at three sites (representative of “city”, “industrial” and “rural” sampling locations) in Lahore, Pakistan, for over a year. The extraction and quantitative analyses of all Lahore air samples was completed for a suite of metals, various anions, ammonium, elemental and organic carbon, as well as particle-associated polycyclic aromatic hydrocarbons (PAHs). A comparison of Lahore yearly mean pollutant concentrations with those obtained in Birmingham, U.K., shows that airborne metal levels in the Pakistani city are greater by at least one order of magnitude. The concentrations in Lahore obtained from this study are broadly in line with similar studies in Karachi as well as Calcutta and Bombay. Concentrations of particle-associated PAH are also around one order of magnitude higher than in U.K. samples, and, given the difference in ambient temperature, vapour-to-particle ratios of PAH are expected to be far higher in the hotter climate of Lahore. Minerals identified by X-ray diffraction (XRD) in the Lahore air samples were broadly in line with those determined at locations in other parts of the world.