Important Source Of Polycyclic Aromatic Hydrocarbons Research Articles

Spatiotemporal distribution and particle–water partitioning of polycyclic aromatic hydrocarbons in Bohai Sea, China

The Bohai Sea is one of the most polluted marine areas in China with polycyclic aromatic hydrocarbons (PAHs) due to its unique hydrological and geographical environment. To investigate differences in PAH concentrations, composition, and particle–water partitioning before and after the rainy reason, water samples were collected during two surveying voyages covering most of the area of the Bohai Sea. Total and dissolved PAH concentrations were higher during the June voyage (total PAHs: 32.29 ± 15.18 ng/L, dissolved PAHs: 31.25 ± 15.26 ng/L) than the August voyage (total PAHs: 15.98 ± 6.39 ng/L, dissolved PAHs: 11.21 ± 5.59 ng/L). The opposite trend was observed for particulate PAHs (June: 1.04 ± 1.01 ng/L, August: 4.78 ± 2.96 ng/L). Among particulate PAHs, an unusually high proportion (65.07%) of low-molecular-weight (LMW) PAHs was observed during the August voyage, which was significantly higher than the proportion during the June voyage (21.86%). This high proportion was inconsistent with the general distribution of PAHs in the aquatic environment according to their physicochemical properties. The excess LMW PAHs adsorbed on suspended particulate matter arose mainly from soil affected by the petrochemical industry of the Bohai Economic Rim, and were carried with particles on runoff into the Bohai Sea during the rainy season. An estimated 5.49 t of LMW PAHs transitioned from the particulate phase to the dissolved phase during the rainy season. This transfer of LMW PAHs from coastal soil to the water column may be an important source of PAHs in the Bohai Sea.

Assessment of uncontrolled PAHs leakage from littered cigarette butts into the urban environment

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants that leak into the environment from various sources, including cigarette butts. In this study, the consequence of the littered cigarette butts on the leakage of 16 typical PAHs into the urban environment was investigated. The results showed that the density of littered cigarette butts in the studied locations was 0.174/m2. The cigarette butt pollution index was in the range of 0.119 to 24.3. 60% of the studied locations were in sever pollution and high pollution status. The total PAHs leakage from littered cigarette butts affected by climatic conditions was estimated to be 2.05 to 4.02 micrograms per square metre. Naphthalene had the largest share among the PAHs types (more than 66%). littered cigarette butts are an important source of PAHs in urban environments, which can be a compelling reason to develop more efficient methods of managing this hazardous waste.

PAHs and nitro-PAHs in urban Beijing from 2017 to 2018: Characteristics, sources, transformation mechanism and risk assessment

Polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (NPAHs) attract continuous attention due to their distinct carcinogenicity and mutagenicity. To investigate the characteristics, sources, formation mechanism and health risk assessment of PAHs and NPAHs, PM2.5 were collected at an urban site in Beijing from 2017 to 2018. The highest PAHs and NPAHs concentrations were 77.92 ± 54.62 ng/m3 and 963.71 ± 695.06 pg/m3 in the winter campaign, which were several times larger than those in other seasonal campaigns. Distinct diurnal variations of nocturnal levels higher than daytime levels were shown for PAHs and NPAHs. Source analysis indicated that besides vehicle exhaust, biomass burning and coal combustion were important sources of PAHs and NPAHs in the fall and winter campaigns. Secondary formation in atmosphere was another source of NPAHs especially in the spring and summer campaigns. NO2 and RH could positively influence the heterogeneous formation of NPAHs when RH was less than 60%. Quantum calculation results confirmed the formation pathway of 2N‐FLA from the OH/NO3-initiated oxidation of FLA. The results of health risk assessment showed the potential health risks for the residents, especially in the winter campaign. These results indicated that PAHs and NPAHs still deserve attention following with the decrease concentrations of particulate matter.

Dissolved polycyclic aromatic hydrocarbons from the Northwestern Pacific to the Southern Ocean: Surface seawater distribution, source apportionment, and air-seawater exchange

Polycyclic aromatic hydrocarbons (PAHs) as a group of toxic and carcinogenic compounds are large scale globally emitted anthropogenic pollutants mainly emitted into the atmosphere. However, atmospheric transport cannot fully explain the spatial variability of PAHs in the marine atmosphere and seawater. It is hypothesized that PAHs accumulated in seawater and ocean circulation can also influence PAHs observed in air above the ocean. In order to investigate PAHs in seawater as a potential secondary source to air, we collected paired air and seawater samples during a research cruise from China to the Antarctic in 2018–2019, covering the Pacific Ocean, the Indian Ocean, and the Southern Ocean. Summed concentrations of 28 analyzed PAHs in seawater were highest in the Pacific Ocean (4000 ± 1400 pg/L), followed by the Indian Ocean (2700 ± 1000 pg/L), and the Southern Ocean (2300 ± 520 pg/L). Three-ringed PAHs dominated the composition profile. We found that PAH levels in the Pacific and Indian Oceans were strong inversely correlated with salinity and distance to the coastline. This suggests that riverine inputs and continental discharges are important sources of PAHs to the marine environment. Derived air-seawater fugacity ratios suggest that net fluxes of PAHs were from seawater to the air in the Pacific and Indian Oceans at 9.0–8100 (median: 1600) ng/m2/d and 290–2000 (median: 1300) ng/m2/d, respectively. In the Southern Ocean, the net flow of PAHs was from air to seawater with a flux of -1000–450 (median: -82) ng/m2/d. Source apportionment from two different models suggested that the largest contribution to total PAHs was from petrogenic sources (44–57%), followed by coal/wood combustion (30–31%), fossil fuel combustion (15%), and engine combustion emissions (2.8–9.5%). Higher contributions from petrogenic sources were found at sites close to coastal regions. Both coal/wood combustion and petrogenic sources are responsible for the PAH concentrations detected in the Indian and Southern Oceans.

Exposure levels and health risk of PAHs associated with fine and ultrafine aerosols in an urban site in northern Algeria.

Size distribution of toxicants in airborne particulates remains insufficiently investigated in Algeria. A 1-year campaign was performed at Bab Ezzouar, Algiers (Algeria), aimed at characterizing particulates for their physical and chemical features. For this purpose, scanning electronic microscopy (SEM), Raman spectroscopy (RaS), and GC-MS methodologies were applied. The samples were collected on daily basis by means of a high-volume sampling (HVS) system equipped with cascade impactor separating three size fractions, i.e., particles with aerodynamic diameters d < 1.0 μm (PM1), 1.0 μm <d<2.5 μm (PM2.5), and 2.5 μm <d<10 μm (PM10), respectively. The organic fraction was recovered from substrate through solvent extraction in an ultrasonic bath, separated and purified by column chromatography, then analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Investigation was focused on polycyclic aromatic hydrocarbons (PAHs) and the concentration ratios suitable to investigate the source nature. Further information was drawn from SEM and Raman analyses. Total PAH concentrations ranged broadly throughout the study period (namely, from 4.1 to 59.7 ng m-3 for PM1, from 2.72 to 32.3 ng m-3 for PM2.5 and from 3.30 to 32.7 ng m-3 for PM10). Both approaches and principal component analysis (PCA) of data revealed that emission from vehicles was the most important PAH source, while tobacco smoke provided an additional contribution.

Polycyclic aromatic hydrocarbons (PAHs) in road dust collected from Quang Ninh: Contamination levels and potential sources

Twenty road dust samples were collected from Ha Long and Cam Pha cities in Quang Ninh province for analysis of polycyclic aromatic hydrocarbons (PAHs) on the USEPA priority pollutant list. Total concentrations of sixteen PAHs in road dust samples of Ha Long and Cam Pha ranged from 232 - 593 ng/g d.w (average: 399 ng/g d.w) and 297 - 1624 ng/g d.w (average: 780 ng/g d.w), respectively. Proportitions of invididiuals were decreased in the order Phe (21% ± 13%) &gt; Pyr (12% ± 6%) &gt; Nap~Fluth (11% ± 6%) &gt; BbF (10% ± 8%), suggesting the similar composition of analyzed PAHs in road dust at two cities. Based on the common diagnostic ratios for the identification of PAHs emission sources, the Fluth/(Fluth+Pyr) ratio (average: 0.43, range: 0.29-0.60), the BaA/(BaA+Chr) ratio (average: 0.30, range: 0.08-0.38), the IcdP/(IcdP+BghiP) ratio (average: 0.30, range: 0.22-0.46) and the BaP/BghiP ratio (average: 0.47 &lt; 0.9) indicated that emissions from traffic activities may be the important sources of PAHs in Quang Ninh.

Extremely high abundance of polycyclic aromatic hydrocarbons in aerosols from a typical coal-combustion rural site in China: Size distribution, source identification and cancer risk assessment

Air quality in China is tending to improve, especially in urban areas. Nevertheless, rural areas and underdeveloped cities in northern China are still suffering from severe air pollution in winter due to large usage of coal and unfavorable meteorological conditions. In this study, size-segregated aerosol samples were collected from a typical coal-combustion rural site in Linfen, China during an extreme air pollution episode in winter 2017. The polycyclic aromatic hydrocarbons (PAHs), n-alkanes, hopanes and steranes were identified to better understand the emission sources of the organic compounds and the health effects of the PAHs in the ambient air here. The PAHs showed a bimodal mode with the major peak in the Aitken mode (<0.4 μm) and the minor one in the size range of 0.7–2.1 μm. Daily PAHs level ranged from 0.5–1.6 μg m−3 (average: 1.1 ± 0.3 μg m−3) which was 1–2 orders of magnitude higher than other major cities in China. The plots of log (PAH/PM)-log(Dp) showed the slope near −1 for four-, five- and six-ring PAHs, indicating both the adsorption and absorption mechanisms controlled the size distribution. The deposition efficiency displayed a bimodal mode in alveolar region (AR), and the major peak was within the Aitken mode. The total deposition flux (DF) in AR region was 92.7 ng h−1, and the DF based lifetime cancer risk (LCR) was about 2.7 × 10−4 for adults and 2.0 × 10−4 for children which were 2 orders of magnitude higher than the acceptable level of 10−6 proposed by United States Environmental Protection Agency (US EPA). In summary, the residential coal combustion was the most important source of PAHs, especially they emitted a large amount of PAHs in Aitken mode which led to the terrible air quality and high level of health risk. Therefore, the environmental protection measures should be tightened in such rural areas of north China.

Coking wastewater treatment plant as a sources of polycyclic aromatic hydrocarbons (PAHs) in sediments and ecological risk assessment

The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in sediments of Maba River, a major tributary of Beijiang River (South China). A total of 13 samples from Maba River and its tributary, Meihua River, were analyzed for 16 PAHs. The total concentration of 16 PAHs (ΣPAH) in high and low water period ranged between 47.61 to 25480.98 ng g−1, with a mean concentration of 4382.98 ng g−1, and 60.30 to 15956.62 ng g−1 with a mean concentration of 3664.32 ng g−1, respectively. Three-ring and four-ring PAHs were the dominant species. It was concluded that a pattern of pyrolytic input as a major source of PAHs in sediments through the molecular ratio method for the source identification, such as HMW/LMW PAHs, Flu/(Flu+Pyr), IcdP/(IcdP+BghiP) and BaA/(BaA+Chr). It is suggested that the pollution emission from the iron and steel plant might be the most important sources of PAHs into Maba River water system. The threat of PAHs contamination to biota of the river was assessed using effect range low (ERL) and effect range median (ERM) values, which suggested that PAHs in Maba River and its tributary had already caused ecological risks.

Analysis and Evaluation of Contamination Status of Polycyclic Aromatic Hydrocarbons (PAHs) in Settled House and Road Dust Samples from Hanoi

Analysis and Evaluation of Contamination Status of Polycyclic Aromatic Hydrocarbons (PAHs) in Settled House and Road Dust Samples from Hanoi

Variation tendency of pollution characterization, sources, and health risks of PM2.5-bound polycyclic aromatic hydrocarbons in an emerging megacity in China: Based on three-year data

In this study, a total of 180 PM2.5 samples were collected from December 3, 2013 to October 20, 2016 in an urban area in Zhengzhou, China, and 16 polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were analyzed. Diagnostic ratio and positive matrix factorization (PMF) were used for annual PAH source identification, and health risks and source regions of PM2.5-bound PAHs were also investigated. Results showed high pollution levels of PM2.5, in which all annual average concentrations substantially exceeded the Chinese standard. Although the PAH concentrations exhibited an evident decreasing trend, PAH pollution remained serious, especially in winter. Combustion, particularly coal combustion and vehicle emission, which were relative sources of 4–5-ring PAHs, played important roles in PAH pollution associated with PM2.5 by diagnostic ratios. PMF results showed that coal combustion had the highest contribution to PM2.5-bound PAHs at 39.6%, 39.6%, and 42.6% and traffic at 29.3%, 25.4%, and 27.9% in 2014–2016, respectively. Biomass burning and coking plants were also important sources of PAHs in PM2.5, with an average contribution of 16.4% ± 1.3% and 15.4% ± 3.5%, respectively. The surrounding region in Henan Province was the key potential source area for PM2.5. However, the northwest and adjoining regions of Zhengzhou were the vital potential sources for PAHs during the entire study period. The concentration levels of benzo[a]pyrene (BaP), ∑16PAHsTEQ, and carcinogenic PAHs remained high, especially for BaP, which had an annual concentration (1.9–5.5 ng/m3) that was considerably higher than the Chinese standard. Carcinogenic risks existed in the order of ingestion > dermal absorption > inhalation and adults > children > seniors > adolescents (except for naphthalene). The risk for females was slightly high, and no remarkable non-carcinogenic risk from PAHs were found.

Carcinogenic Potency of Airborne Polycyclic Aromatic Hydrocarbons in Relation to the Particle Fraction Size.

Polycyclic aromatic hydrocarbons (PAHs) that are bound to particulate matter can have adverse effects on human health. Particle size plays an important role in assessing health risks. The aim of this study was to compare concentrations of PAHs bound to particle fractions PM10, PM2.5, and PM1, as well as to estimate their carcinogenic potency and relative contributions of the individual PAHs to the carcinogenic potency in relation to the size of the particle. Measurements of ten PAHs were carried out in 2014 at an urban location in the northern part of Zagreb, Croatia. 24-h samples of the PM10, PM2.5, and PM1 particle fraction were collected over forty days per season. Carcinogenic potency of PAHs was estimated by calculating benzo(a)pyrene equivalent concentrations while using three different toxic equivalence factor (TEF) schemes. The total carcinogenic potency (TCP) and percentage contributions differed significantly depending on the TEF scheme used. The lowest PAH mass concentrations and TCPs were in summer and the highest in winter. The contributions of individual PAHs to the sum of PAH mass concentrations remained similar in all fractions and seasons, while in fractions PM10–2.5 and PM2.5–1 they varied significantly. Road traffic represented the important source of PAHs in all fractions and throughout all seasons. Other sources (wood and biomass burning, petroleum combustion) were also present, especially during winter as a consequence of household heating. The highest contribution to the TCP came from benzo(a)pyrene, dibenzo(ah)antrachene, indeno(1,2,3,cd)pyrene, and benzo(b)fluoranthene (together between 87% and 96%) in all fractions and seasons. In all cases, BaP showed the highest contribution to the TCP regardless relatively low contributions to the mass of total PAHs and it can be considered as a good representative for assessing the carcinogenicity of the PAH mixture. When comparing the TCP of PAHs in PM10 and PM2.5 fractions, it was found that about 21–26% of carcinogenic potency of the PAH mixture belonged to the PM2.5 fraction. Comparison of TCP in PM2.5 and PM1 showed that about 86% of carcinogenic potency belonged to the PM1 fraction, regardless of the TEF scheme used.

Assessing the level and sources of Polycyclic Aromatic Hydrocarbons (PAHs) in soil and sediments along Jhelum riverine system of lesser Himalayan region of Pakistan

Lesser Himalayan Region (LHR) is an important mountain ecosystem which supports a wide range of biodiversity for native flora and fauna. Human population in this region is largely dependent upon local sources for their livelihood. Surface soil (n = 32) and sediment (n = 32) were collected from four different altitudinal ranges of LHR and analyzed for priority Polycyclic Aromatic Hydrocarbons (PAHs) recommended by USEPA. Level, sources and distribution pattern of PAHs were assessed in soil and sediments samples collected from four altitudinal zones in LHR. Total PAHs concentration level of PAHs in soil and sediments ranged from 62.79 to 1080 ng g−1 and 14.54–437.43 ng g−1, respectively. Compositional profile of PAHs in both soil and sediment were dominated by low and medium molecular weight PAHs, ranged from 18.02 to 402.18 ng g−1in soil and 0.32–96.34 ng g−1in sediments. In the context of spatial distribution trend, highest mean concentrations of PAHs in soil were recorded in zone D (sites from the rural region) and for sediments highest concentrations were detected at zone A, which includes dam sites. In all four zones, no altitudinal trend of PAHs in soil and sediments was observed. Source apportionment through receptor modelling by positive matrix factorization (PMF) revealed that local sources such as biomass combustion and vehicular emissions are important sources of PAHs in this region. The prevalence of monsoon atmospheric circulation system in LHR implicated that this region is also influenced by medium and long range atmospheric transportation of PAHs from neighboring countries where potential sources and high level of PAHs has been reported.

The Role of Sources and Atmospheric Conditions in the Seasonal Variability of Particulate Phase PAHs at the Urban Site in Central Poland

The 24-h records of polycyclic aromatic hydrocarbons (PAHs) concentrations in the particulate phase were obtained for the urban site (52.42°N, 16.88°E) in Poznan, one of the largest cities in central Poland, between January and December 2014. The main goal of this study was to identify major emission sources of PAHs congeners and factors controlling their seasonal variability. The most abundant in the particulate matter PAH compound was pyrene (mean concentration of 2.29 ± 4.68 ng m–3, maximum of 22.51 ng m–3), followed by benzo(a)pyrene, dibenz(ah)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene, phenanthrene, benzo(ghi)perylene, chrysene, benz(a)anthracene and fluoranthene. The results showed a sharp decrease in PAHs concentrations during summer measurements (photodecomposition, high precipitation frequency), and high levels of the quantified PAHs during cold study period (increase anthropogenic emission, low air temperature). During the cold season in 2014, predominant PAHs congeners were: pyrene (26.0%) and 5-ring PAH compounds such as benzo(a)pyrene (19.4%) > dibenz(ah)anthracene (13.7%) ≥ benzo(k)fluoranthene (13.3%) > benzo(b)fluoranthene (9.8%), mostly associated with mixed sources (i.e., combustion, wood burning, industrial emission, traffic emission), whereas during warm study period we observed a large contribution (> 20%) of pyrene, dibenz(ah)anthracene and benzo(a)pyrene in particulate matter. The summertime measurements showed that local emission from the traffic (i.e., diesel and gasoline exhausts) was the second important source of PAHs in aerosol. The coal combustion for residential heating and industrial usage were most pronounced PAHs sources during the entire study period. The multivariate statistical technique (Principal Component Analysis) combined with some diagnostic ratios were applied to provide detailed characteristics of sources and processes related to the polycyclic aromatic hydrocarbons in different seasons. The results from this study are in good agreement with most of the studies focused on seasonal variability of PAHs in the atmosphere.

Street foods exacerbate effects of the environmental burden of polycyclic aromatic hydrocarbons (PAHs) in Nigeria.

Polycyclic aromatic hydrocarbons (PAHs) are a large group of well-known toxicants with carcinogenic potential and other health effects including on the immune system. The high health risks of non-communicable diseases and relevant comorbidities in Africa, particularly in contaminated areas like e-waste and crude oil and gas exploration areas and for high consumers of food commodity groupings which are most critical for PAH exposure, are exacerbated by dietary exposure due to unsafe practices in commonly consumed foods, like those street vended.In February 2016, 20 commonly consumed street foods were purchased directly from vendors at major bus stops in Benin City and Umunede in Nigeria. The concentration of 16 priority PAHs was determined. The dietary intake of B[a]P, ∑PAH, PAH4, PAH8, and ∑B(a)Peq was estimated for children, peripubertal children/adolescent, and adult using the total diet study (TDS) method. Among the analyzed PAHs, there was a predominance of chrysene (17.42μg/kg). Roasted yam (14.15μg/kg) and fried fish (1.40μg/kg) had the highest levels of ∑PAH and B[a]P, respectively. The mean concentration of B[a]P, ∑PAH, PAH4, PAH8, and ∑B(a)Peq ranged from 0.65-1.40μg/kg, 0.20-14.15μg/kg, 0.43-5.22μg/kg, 0.13-7.88μg/kg, and 0.002-2.123μg/kg, respectively. The mean concentration of B[a]P and PAH4 reported in this study was below the maximum allowable levels of 5 and 12μg/kg for adults and above the maximum levels for young children set at 1.0μg/kg for both B[a]P and PAH4 in food. The estimated dietary intake of B[a]P, ∑PAH, PAH4, PAH8, and ∑B(a)Peq for adult, adolescent, and children was 0.56, 0.37, and 0.31μg/day; 17.6, 10.7, and 8.81μg/day; 5.78, 4.01, and 3.26μg/day; 9.22, 6.19, and 5.09μg/day; and 1.72, 0.97, and 0.82μg/day, respectively.Street foods represent one important source of PAHs. The exposure occurring through street food compounds with that from home-made foods, environmental pollution, and lifestyle (tobacco smoke) is making up an aggregate daily exposure in the general population.The incremental lifetime cancer risk for adults and children from the consumption of street food was 7.6 × 10-8 and 2.1 × 10-8, respectively. Along with initiatives to manage environmental contamination and promote healthier lifestyle, people should be empowered on healthy cooking practices and safe food cookery environments.

Seasonal variation, spatial distribution and source apportionment for polycyclic aromatic hydrocarbons (PAHs) at nineteen communities in Xi'an, China: The effects of suburban scattered emissions in winter

Seasonal variation and spatial distribution of PM2.5 bound polycyclic aromatic hydrocarbons (PAHs) were investigated at urban residential, commercial area, university, suburban region, and industry in Xi'an, during summer and winter time at 2013. Much higher levels of total PAHs were obtained in winter. Spatial distributions by kriging interpolations principle showed that relative high PAHs were detected in western Xi'an in both summer and winter, with decreasing trends in winter from the old city wall to the 2nd-3rd ring road except for the suburban region and industry. Coefficients of diversity and statistics by SPSS method demonstrated that PAHs in suburban have significant differences (t < 0.05) with those in urban residential in both seasons. The positive Matrix Factorization (PMF) modeling indicated that biomass burning (31.1%) and vehicle emissions (35.9%) were main sources for PAHs in winter and summer in urban, which different with the suburban. The coal combustion was the main source for PAHs in suburban region, which accounted for 46.6% in winter and sharp decreased to 19.2% in summer. Scattered emissions from uncontrolled coal combustion represent an important source of PAHs in suburban in winter and there were about 135 persons in Xi'an will suffer from lung cancer for lifetime exposure at winter levels. Further studies are needed to specify the effluence of the scattered emission in suburban to the city and to develop a strategy for controlling those emissions and lighten possible health effects.

Characteristics, identification, and potential risk of polycyclic aromatic hydrocarbons in road dusts and agricultural soils from industrial sites in Shanghai, China.

Road dusts and agricultural soil samples were collected from eight sites close to steel mills, chemical plants, and municipal solid waste incinerator in suburban Shanghai. Sixteen polycyclic aromatic hydrocarbons (PAHs) in the United States Environmental Protection Agency (US EPA) priority controlled list were analyzed quantitatively using GC-MS. The total PAH concentrations ranged from 0.79 to 6.2μgg-1 in road dust samples with a mean value of 2.38μgg-1 and 0.26 to 0.54μgg-1 in agricultural soils with an average of 0.36μgg-1. The most abundant individual PAHs were phenanthrene, fluoranthene, pyrene, chrysene, and benzo(b)fluoranthene in dust samples and phenanthrene, fluoranthene, chrysene, and benzo(b)fluoranthene, benzo (k) fluoranthene in soil samples. Dominant compounds were four-ring and five- to six-ring PAHs, which accounted for 41.5 and 31.5% in dusts and 33.9 and 41.1% in soils. The spatial distribution of PAHs in dusts and soils was consistent. The wind direction could affect the spatial distribution of PAHs. Organic matter contents were found to be significantly positively correlated with PAH concentrations in both dusts and soils while grain size of particles had no correlation with PAH concentrations and could not significantly influence the distribution of PAH concentrations. PAH isomer ratios showed that combustion of grass, wood, and coal was important sources of PAHs in road dusts and agricultural soils. Toxic equivalent concentrations indicated seven kinds of carcinogenetic PAHs were major toxic equivalent concentration (TEQ) contributors, accounting for 98% of TEQ, in the road dusts and agricultural soils. Incremental lifetime cancer risk (ILCR) estimation results showed that the PAHs in the dusts and soils had potential cancer risk for both children and adults only by direct ingestion exposure. The TEQ and ILCR values of PAHs in road dusts were much higher than those in soils, which suggested that PAHs in road dusts could be an important source of PAHs in soils.

Spatio-temporal variations and influencing factors of polycyclic aromatic hydrocarbons in atmospheric bulk deposition along a plain-mountain transect in western China

Ten atmospheric bulk deposition (the sum of wet and dry deposition) samplers for polycyclic aromatic hydrocarbons (PAHs) were deployed at a plain-mountain transect (namely PMT transect, from Daying to Qingping) in Chengdu Plain, West China from June 2007 to June 2008 in four consecutive seasons (about every three months). The bulk deposition fluxes of ∑15-PAHs ranged from 169.19 μg m−2 yr−1 to 978.58 μg m−2 yr−1 with geometric mean of 354.22 μg m−2 yr−1. The most prevalent PAHs were 4-ring (39.65%) and 3-ring (35.56%) PAHs. The flux values were comparable to those in rural areas. Higher fluxes of total PAHs were observed in the middle of PMT transect (SL, YX and JY, which were more urbanized than other sites). The seasonal deposition fluxes in the sampling profile indicated seasonality of the contaminant source was an important factor in controlling deposition fluxes. PAHs bulk deposition was negatively correlated with meteorological parameters (temperature, wind speed, humidity, and precipitation). No significant correlations between soil concentrations and atmospheric deposition were found along this transect. PAHs in soil samples had combined sources of coal, wood and petroleum combustion, while a simple source of coal, wood and grass combustion for bulk deposition. There were significant positive correlation relationship (p < 0.05) between annual atmospheric bulk deposition and local PAHs emission, with biomass burning as the major contribution to the total emission of PAHs. This transect acts as an important PAHs source rather than being a sink according to the ratio of deposition/emission. Mountain cold trap effect existed in this transect where the altitude was higher than 1000 m. Long-range transport had an impact on the bulk deposition in summer. And this transect was a source to Tibetan only in summer. The forward trajectory analysis showed most air masses did not undergo long-range transport due to the blocking effect of surrounding mountains. Only a few air masses (<10%) arrived at the eastern and northern region of China or farther regions via long-range transport.

Concentrations, Trends, and Air-Water Exchange of PAHs and PBDEs Derived from Passive Samplers in Lake Superior in 2011.

Polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenylethers (PBDEs) are both currently released into the environment from anthropogenic activity. Both are hence primarily associated with populated or industrial areas, although wildfires can be an important source of PAHs, as well. Polyethylene passive samplers (PEs) were simultaneously deployed in surface water and near surface atmosphere to determine spatial trends and air-water gaseous exchange of 21 PAHs and 11 PBDEs at 19 sites across Lake Superior in 2011. Surface water and atmospheric PAH concentrations were greatest at urban sites (up to 65 ng L(-1) and 140 ng m(-3), respectively, averaged from June to October). Near populated regions, PAHs displayed net air-to-water deposition, but were near equilibrium off-shore. Retene, probably depositing following major wildfires in the region, dominated dissolved PAH concentrations at most Lake Superior sites. Atmospheric and dissolved PBDEs were greatest near urban and populated sites (up to 6.8 pg L(-1) and 15 pg m(-3), respectively, averaged from June to October), dominated by BDE-47. At most coastal sites, there was net gaseous deposition of BDE-47, with less brominated congeners contributing to Sault Ste. Marie and eastern open lake fluxes. Conversely, the central open lake and Eagle Harbor sites generally displayed volatilization of PBDEs into the atmosphere, mainly BDE-47.

Polycyclic aromatic hydrocarbons in sediments of China Sea.

Increasing pollution pressures were placed in the coastal and estuarine ecosystems in China because of the elevated pollutants discharged from various sources. Polycyclic aromatic hydrocarbons (PAHs) in the environment were closely linked to human activities, which have been intensively studied for their geochemical interest as markers. In this review, the status of PAH contamination in China Sea was assessed by comprehensive reviews of the concentrations, sources, and fates of PAHs in sediments of China Sea. PAH concentrations in China Sea sediments decreased from north to south due to the higher emissions in North China. Atmosphere was probably the main carrier of PAHs in the north due to the higher contents of atmospheric fine particles and higher wind speeds. However, riverine inputs were probably the most important sources of PAHs in the coastal sediments of South China due to higher rainfall.

Characteristics of polycyclic aromatic hydrocarbons in agricultural soils at a typical coke production base in Shanxi, China

There is wide concern about polycyclic aromatic hydrocarbons (PAHs) because of their carcinogenic and mutagenic potential. The coking industry is an important source of PAHs. In this study, 36 arable soil samples, a sensitive medium from the perspective of food safety and health, were collected from one of the largest coke production bases in China. The concentration of total 21 PAHs ranged from 294 to 1665ngg−1, with a mean of 822±355ngg−1. Approximately 60% of the soil samples were heavily polluted with the level higher than 600ngg−1. Particularly high abundances of high molecular weight PAHs were found, and the calculated BaPeq was as high as 54.3ngg−1. Soil PAH levels were positively correlated with soil organic matter content. The soil PAHs were from complex mixture sources, and high-temperature pyrogenic sources were most likely responsible for the heavy PAH contamination. Effective control strategies and probable remediation approaches should be proposed to improve soil quality.