Main Sources Of Polycyclic Aromatic Hydrocarbons Research Articles

Polycyclic aromatic hydrocarbons in fish from four lakes in central and eastern China: Bioaccumulation, pollution characteristics, sources, and health risk assessment

Polycyclic aromatic hydrocarbons (PAHs) are highly concerning environmental pollutants due to their toxicity, persistence, and bioaccumulation. In this paper, concentrations and compositions of 16 United States Environmental Protection Agency (USEPA) priority control PAHs in the fish collected from four lakes in central and eastern China were analyzed. 18 species of fish were collected from four typical lakes, namely Taihu Lake, Danjiangkou Reservoir, Yuncheng Salt Lake, and Nansi Lake. Quantitative analysis of PAHs were carried out with gas chromatograph/mass spectrometer, and 13 out of 16 PAHs were identified, with the main components being pyrene, chrysene, naphthalene, and benzo(b)fluoranthene. The accumulation of PAHs in fish from Taihu Lake, Danjiangkou Reservoir, Yuncheng Salt Lake, and Nansi Lake was 28.75–47.27, 26.60–31.93, 33.56–39.30, and 27.22–43.01 ng·g−1, respectively. The toxic equivalents of high-cyclic PAHs in fish of the four lakes were significantly higher than those of low-cyclic and middle-cyclic PAHs (P < 0.05). In Taihu Lake, Danjiangkou Reservoir, and Nansi Lake, the toxicity equivalents were predominantly contributed by benzo[a] pyrene (BaP), while in Yuncheng Salt Lake, dibenzo(a,h) anthracene (DahA) was the main contributor. The residents in central and eastern China exposed to PAHs had a negligible non-cancer risk (non-carcinogenic risk values <1) and a potential low cancer risk. It was noteworthy that the Pleuronichthys cornutus and Lateolabrax japonicus from Yuncheng Salt Lake could pose carcinogenic risks (>10−4) to humans, with benzo[b]fluoranthene (BbF) having the highest risk contribution rate. Source analysis indicated that the main source of PAHs in fish was combustion sources. BaP, DahA, and BbF could become potential pollutants of concern in the field of ecotoxicology. The results of this study on PAHs bioaccumulation, pollution characteristics, sources and health risks in fish from four lakes would provide a scientific basis for local governments to formulate targeted environmental management policies, pollution control measures, and public health strategies.

Characteristics, sources, and health risks of PAHs and their derivatives in indoor dust in Zhengzhou

The occurrence, source, and health risk of polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and oxy-PAHs (OPAHs) in indoor dust collected from three types of microenvironments (offices, classrooms, and dormitories) at a university campus in Zhengzhou were analysed. The results showed that the average concentration of the total PAHs was 2403.21±981.99 ng g-1, with PHE (20.06% of Σ18PAHs) and BkF (15.46%) being the dominant species. The average concentrations of total NPAHs and OPAHs were 11.09±5.12 and 385.80±255.27 ng g-1, with 2+3N-FLT (39.15%) and 9-FLO (39.76%) as the most abundant species of NPAHs and OPAHs, respectively. The average concentrations of total PAHs, NPAHs, and OPAHs in different microenvironments displayed obvious spatial specificity with the highest values in dormitories. The main source of PAHs, as identified by diagnostic ratios, was petroleum combustion, coal/biomass combustion and vehicle exhaust emissions. The average incremental lifetime cancer risk (ILCR) for undergraduates exposed to dust in classrooms and dormitories exceeded 10-6, indicating a potential cancer risk. The most important exposure pathway was dermal contact, while the inhalation route was negligible.

Identification and seasonal variation of specific particulate bound (halogenated) polycyclic aromatic hydrocarbons in air from different metal industrial parks in Northwest China.

During the process of industrial heating, a large amount of polycyclic aromatic hydrocarbons (PAHs) and their halogenated compounds (Cl/Br-PAHs) can be formed. However, there is still limited understanding of the chemicals from different metal smelting industrial parks. This study evaluated the seasonal variations, composition profiles, and source allocations of the atmospheric particulate-bound PAHs and Cl/Br-PAHs in different metal industrial parks in a typical industrial city in northwest China. The results showed that the main PAHs produced by metal smelting were low molecular weight isomers, and the concentrations of Cl-PAHs were lower compared to Br-PAHs. The main Br-PAHs were 1-Br-Pyr and 4-Br-Pyr, while 9-Cl-Fle, 1-Cl-Pyr, and 6-Cl-BaP were the dominated Cl-PAH isomers. No significant difference was found in the concentrations among the sites, whereas the levels of the target chemicals were higher during cold months compared to warm months. The main source of PAHs was coal combustion and gasoline vehicle emission during metal smelting, and that of Cl/Br-PAHs was also industrial coal burning. In addition to the primary source, the secondary chlorination of parent PAHs was also a significant source of Cl-PAHs in the production of high purity aluminum. This study suggests that Cl-PAHs and Br-PAHs may behave differently in the atmosphere.

Characteristics, Sources Apportionment, and Health Risks of PM2.5-bound PAHs and Their Derivatives Before and After Heating in Zibo City

Atmospheric polycyclic aromatic hydrocarbons (PAHs) and their derivatives are a global problem that influences the environment and threatens human health. To investigate the characteristics, sources, and health risk assessment of PM2.5-bound PAHs and their derivatives, PM2.5 were collected at an urban site in Zibo from November 5 to December 26, 2020, and the concentrations of 16 conventional PAHs, nine NPAHs, and five OPAHs in PM2.5 were analyzed using gas chromatography-mass spectrometry. Source apportionment of PAHs and their derivatives was conducted using diagnostic ratios and a PMF model, and the health risks of PAHs and their derivatives to adult men and women were evaluated using the source-dependent incremental lifetime cancer risk (ILCR) model. The results showed that the average concentrations of ∑16pPAHs, ∑9NPAHs, and ∑5OPAHs in PM2.5 of Zibo City during the sampling period were (41.61 ± 13.40), (6.38 ± 5.70), and (53.20 ± 53.47) ng·m-3, respectively. The concentrations of the three PAHs increased significantly after heating, which were 1.31, 2.04, and 5.24 times larger than those before heating. During the sampling period, Chr, BaP, and BaA were the dominant components of pPAHs; 9N-Ant and 2N-Flt + 3N-Flt were the dominant components of NPAHs; and ATQ and BZO were the dominant components of OPAHs. Source apportionment results showed that motor vehicles were the main source of PAHs and their derivatives in PM2.5 before heating, whereas after heating, the main sources were the mixed source of coal and biomass combustion and secondary formation. The total BaP equivalent (TEQ) was 14.5 ng·m-3 during the sampling period, and the TEQ increased significantly after heating, which was approximately 1.2 times of that before heating. Assisted by the individual PAH source apportionment results, the ILCR of PM2.5-boundPAHs and NPAHs in Zibo City had a certain potential carcinogenic risk for adult males (1.06 × 10-5) and females (9.32 × 10-6). Among them, the health risks of PAHs from gasoline vehicles, diesel vehicles, and coal/biomass combustion were significantly higher than those from other emission sources.

Occurrence, removal, and risk assessment of polycyclic aromatic hydrocarbons and their derivatives in typical wastewater treatment plants

Wastewater treatment plants (WWTPs) have a certain removal capacity for polycyclic aromatic hydrocarbons (PAHs) and their derivatives, but some of them are discharged with effluent into the environment, which can affect the environment. Therefore, to understand the presence, sources, and potential risks of PAHs and their derivatives in WWTPs. Sixteen PAHs, three chlorinated polycyclic aromatic hydrocarbons (ClPAHs), three oxidized polycyclic aromatic hydrocarbons (OPAHs), and three methylated polycyclic aromatic hydrocarbons (MPAHs) were detected in the influent and effluent water of three WWTPs in China. The average concentrations of their influent ∑PAHs, ∑ClPAHs, ∑OPAHs, and ∑MPAHs ranged from 2682.50 to 2774.53 ng/L, 553.26–906.28 ng/L, 415.40–731.56 ng/L, and 534.04–969.83 ng/L, respectively, and the effluent concentrations ranged from 823.28 to 993.37 ng/L, 269.43–489.94 ng/L, 285.93–463.55 ng/L, and 376.25–512.34 ng/L, respectively. The growth of heat transport and industrial energy consumption in the region has a significant impact on the level of PAHs in WWTPs. According to the calculated removal efficiencies of PAHs and their derivatives in the three WWTPs (A, B, and C), the removal rates of PAHs and their derivatives were 69–72%, 62–71%, and 68–73%, respectively, and for the substituted polycyclic aromatic hydrocarbons (SPAHs), the removal rates were 41–49%, 31–40%, and 33–39%, respectively; moreover, the removal rates of PAHs were greater than those of SPAHs in the WWTPs. The results obtained via the ratio method indicated that the main sources of PAHs in the influent of WWTPs were the combustion of coal and biomass, and petroleum contamination was the secondary source. In risk evaluation, there were 5 compounds for which the risk quotient was considered high ecological risk. During chronic disease evaluation, there were 11 compounds with a risk quotient considered to indicate high risk. PAHs and SPAHs with high relative molecular masses in the effluent of WWTPs pose more serious environmental hazards than their PAHs counterparts.

Risk Assessments of Polycyclic Aromatic Hydrocarbons in the Surface Sediments of Drinking Water Sources in Ifite Ogwari, South-East Nigeria

ABSTRACT Surface water is the main source of drinking water in Ifite Ogwari, Anambra State, South-East Nigeria. In aquatic environments, sediment functions as both a source and a sink of polycyclic aromatic hydrocarbons (PAHs). To determine the level of pollution, health concerns to people and the environment, and potential sources of PAHs in the surface water sediments in Ifite Ogwari, sediment samples were collected from 9 surface water sources used for drinking by Ifite Ogwari people and were analyzed using a Gas Chromatography/Flame Ionization Detector (GC-FID). In all sediment samples, only 11 PAHs out of 16 United States Environmental Protection Agency (USEPA) priority PAHs were detected while 5 were below detectable limits. The concentration of benzo[a]anthracene was high but detected in only 2 sediment samples while fluoranthene has a relatively close concentration across all samples. Benzo[k]fluoranthene has the highest concentration compared to other PAHs in the samples while benzo[a]pyrene has the lowest concentration across all samples. Atammele sediment was analyzed as the most carcinogenic followed by Isiachala with concentrations of 84.23 ng/µL and 51.92 ng/µL respectively. Ube stream sediment has the lowest concentration of PAHs (11.74 ng/µL). Ecological risk of the PAHs revealed a sediment-to-sediment variation in the risk profile. Human health risk assessment depicts that hazard index and total cancer risk for adults and children ranged from 2.3E-07 - 2.57E-05 and 4.85E-07 - 5.43E-05 respectively. Pyrogenic activities are the main source of PAHs in the sediments. The results provide a guide for monitoring PAHs pollution and protecting drinking water sources.

Spatial-temporal Distribution and Source Analysis of Polycyclic Aromatic Hydrocarbons in the Sediments of Poyang Lake

The concentrations, spatial-temporal distribution, and influencing factors of 16 polycyclic aromatic hydrocarbons (PAHs) in the sediments of Poyang Lake were studied, and a quantitative source analysis of PAHs in different areas of the lake was conducted. PAHs were widespread within the sediments. The concentrations of ∑16PAHs in the surface sediments of all sites ranged from 203 to 2 318 μg·kg-1. The concentrations of PAHs in the surface sediments of the lake body were higher than those in the surface sediments of the inlet rivers. The ratio of PAHs in Poyang Lake was 4 rings > 5 rings > 6 rings > 3 rings > 2 rings; the composition of 4-ring PAHs was dominant, and its content accounted for 86.11% of ∑16PAHs. The 2- and 3-ring and some 4-ring PAHs, including Flua and Pyr, were more susceptible to SOM, and the 4 through 6-ring PAHs were more susceptible to ORP and heavy metals and other environmental factors. Spatially, the higher concentration of ∑16PAHs occurred in the area of the lake adjacent to Duchang County and Poyang County, where the terrain was relatively closed, and the water exchange with the surrounding area was less than that in other sections, which was not conducive to the migration, transformation, and degradation of pollutants. In the temporal distribution, the changes in PAHs concentration level and the development of GDP in Jiangxi Province showed high consistency, and the influence of economic development and human activities might have been the main reason for the increasing PAHs concentration level. The main sources of PAHs in surface sediments of Poyang Lake included petroleum pollution and oil and coal and biomass combustion sources, and there were some spatial differences in PAHs sources in different regions. This study can provide a reference for PAHs pollution in surface sediments of Poyang Lake, which is important for the ecological environmental protection and management of Poyang Lake.

Sediment records and multi-media transfer and fate of polycyclic aromatic hydrocarbons in Dianchi Lake over the past 100 years

This study analyzed the fate and transfer of PAHs through multiple media in Dianchi Lake and the sediment records of polycyclic aromatic hydrocarbons (PAHs) in sediments. The model simulation results showed the simulated concentrations to be in good agreement with the measured values. The concentration and total amount of PAHs were the highest in the sediment, which is an important sink for PAHs in lake systems. The main transport direction of the PAHs in the three phases was from the atmosphere to the water to the sediment. Advection and emission inputs were the primary input pathways for PAHs in the atmosphere, and advection output was the main removal path. The main input sources pathways for PAHs in sediments was the sedimentation of particulate matter in water, with diffusion and degradation being the primary methods of removal. Advection and atmospheric dry and wet deposition were the main sources of PAHs in water, with particulate deposition being the primary removal process. The range of PAHs was 336–3520 ng/g in sediments in Dianchi Lake, with an average of 1569 ng/g, peaking in 2012. Among the predicted future PAH concentrations in the sediments under the five shared socioeconomic pathways (SSPs), the lowest PAH concentration was found under SSP3 from 2025 to 2035, whereas the lowest PAH concentration was found under SSP4 from 2035 to 2050. In the sustainable path of SSP1, although the concentration of PAH pollutants showed an increasing trend in the short term, the increase in PAHs concentration in sediments slowed in the long run.

Distribution characteristics, source analysis and risk assessment of polycyclic aromatic hydrocarbons in sediments of Kuye River: a river in a typical energy and chemical industry zone.

This study systematically analyzed the distribution characteristics, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in Kuye River sediments, located in an energy and chemical industry base in northern Shaanxi, China. The results that revealed the concentrations of 16 PAHs in the sediment ranged from 1090.04 to 32,175.68ng∙g-1dw, with the four-ring PAHs accounting for the highest proportion. Positive matrix factorization analysis (PMF) revealed the main sources of PAHs as incomplete fossil fuel combustion, biomass combustion, and traffic emissions. The total toxic equivalent concentration of BaP, risk quotient, and lifetime carcinogenic risk of PAHs suggested moderate to high contamination of PAHs in the area. The higher incremental lifetime carcinogenic risk (ILCR) indicated that PAH ingestion was the primary route of impact on public health, with children potentially being more susceptible to PAH exposure. This study can provide valuable theoretical support for implementing pollution prevention measures and ecological restoration strategies for rivers in energy and chemical industry areas.

Pollution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Soils of Guangzhou

In order to comprehensively study the pollution characteristics of polycyclic aromatic hydrocarbons （PAHs） in soils of Guangzhou， 222 topsoil samples were collected and analyzed. The ecological risk of soil PAHs pollution was evaluated using the effect interval low/median method （ERL/ERM） and the （BaP） toxicity equivalent method， and the health risk of soil PAHs pollution was evaluated using the lifelong cancer risk increment model. The source of PAHs was analyzed using the characteristic compound ratio method and PMF model. The results indicated that： the content of surface soil （∑16PAHs） in Guangzhou was 38-11 115 μg·kg-1， with an average of 526 μg·kg-1， and 16 types of polycyclic aromatic hydrocarbon monomers showed strong variation. There was a certain degree of ecological risk of PAHs in Guangzhou， and there was already a significant ecological risk of PAHs pollution in individual sampling points， which were generally in a state of mild pollution. Based on the results of the health risk assessment， the contribution rates of total cancer risk in both adults and children were presented as follows： skin contact &gt; ingestion of soil &gt; respiratory intake. The health risk of children was greater than that of adults， and the overall health risk was within an acceptable range. Source analysis showed that the main sources of soil PAHs in Guangzhou were coal （37.1%）； diesel （32%）； coking （17.3%）； and mixed sources of traffic emissions， biomass combustion， and petrochemical product volatilization （13.6%）. The overall source of soil PAHs belonged to mixed sources. The research results have enriched our understanding of the pollution status of PAHs in the surface soil of Guangzhou and are helpful in promoting soil pollution prevention and control actions.

Particulate polycyclic aromatic hydrocarbons in rural households burning solid fuels in Xuanwei County, Southwest China: occurrence, size distribution, and health risks.

The study is about the size distribution and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor environment of Xuanwei, Southwest China particle samples were collected by Anderson 8-stage impactor which was used to gather particle samples to nine size ranges. Size-segregated samples were collected in indoor from a rural village in Xuanwei during the non-heating and heating seasons. The results showed that the total concentrations of the indoor particulate matter (PM) were 757 ± 60 and 990 ± 78 μg/m3 in non-heating and heating seasons, respectively. The total concentration of indoor PAHs reached to 8.42 ± 0.53 μg/m3 in the heating season, which was considerably greater than the concentration in the non-heating season (2.85 ± 1.72 μg/m3). The size distribution of PAHs showed that PAHs were mainly enriched in PMs with the diameter <1.1 μm. The diagnostic ratios (DR) and principal component analysis (PCA) showed that coal and wood for residential heating and cooking were the main sources of indoor PAHs. The results of the health risk showed that the total deposition concentration (DC) in the alveolar region (AR) was 0.25 and 0.68 μg/m3 in the non-heating and heating seasons respectively. Throughout the entire sampling periods, the lifetime cancer risk (R) based on DC of children and adults varied between 3.53 ×10-5 to 1.79 ×10-4. During the heating season, the potential cancer risk of PAHs in adults was significant, exceeding 10-4, with a rate of 96%.

Levels and sources of polycyclic aromatic hydrocarbons (PAHs) near hospitals and schools using leaves and barks of Sambucus nigra and Acacia melanoxylon

Polycyclic aromatic hydrocarbons (PAHs) are among the most studied organic compounds in urban environments, due to their known threat to human health. This study extends the current knowledge regarding the ability of different vegetative parts of different tree species to accumulate PAHs. Moreover, exposure intensity to PAHs in areas frequented by population susceptible to adverse health effects of air pollution is evaluated. For this, leaves and barks of Sambucus nigra (S. nigra) and Acacia melanoxylon (A. melanoxylon) were collected at urban areas in the Andean city of Quito, at seven points near hospitals and schools. A methodology, previously developed, for the extraction, purification, and quantification of PAHs associated with the leaves and bark of S. nigra was employed and also validated for leaves and bark of A. melanoxylon. The total PAH level varied from 119.65 ng g−1 DW (dry weight) to 1969.98 ng g−1 DW (dry weight) with naphthalene (Naph), fluoranthene (Flt), pyrene (Pyr), chrysene (Chry), and benzo[a]pyrene (BaP) predominating in all samples. The results indicate that the leaves and bark of tree species studied have certain abilities to bio-accumulate PAH according to their molecular weight. The leaves of S. nigra and bark of A. melanoxylon showed the highest ability to accumulate PAHs, mainly those with high and medium molecular weight, respectively. The highest incidence of light molecular weight PAHs was found in the leaves of A. melanoxylon. Furthermore, coal combustion, biomass burning, and vehicle emissions were identified as the main PAHs sources. Concentrations of PAHs associated with tree species suggest an affectation in areas frequented by populations susceptible to air pollution. This fact shows the importance of regulatory scheme to significantly improve the air quality in the city integrating a knowledge-based decision-making.

The occurrence characteristics, removal efficiency, and risk assessment of polycyclic aromatic hydrocarbons in sewage sludges from across China

Sewage sludge is considered to be an important sink for polycyclic aromatic hydrocarbons (PAHs) in wastewater treatment plants and the potential risks from sludge contaminated with PAHs during land application has attracted attention. To identify the priority PAHs for control and enhance their removal from sludge, the occurrence characteristics, removal efficiency, and risk assessment of PAHs in sewage sludges from across China were analyzed. Data collection was from 2001 to 2023. Results showed that 16 PAHs were widely detected in Chinese sewage sludge with total amounts (∑16PAHs) between 0.06 and 34.93 mg kg dw−1. Fossil fuel, coal, and biomass combustion are main anthropogenic sources of PAHs in China. In general, phenanthrene (PHE), anthracene (ANT), fluorescein (FL), chrysene (CHR), pyrene (PYR), and benzo[b]fluoranthene (BbF) are regarded as the main components and PAHs with 3–5 rings dominate (84.01%–91.53%) sewage sludge in China. Although aerobic composting and anaerobic treatment significantly improve ∑16PAHs removal, sludge stabilization treatment only reduced the risk by a small amount, especially for high-molecular-weight (HMW) PAHs. The benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), and dibenzo[a,h]anthracene (DahA) are proposed as the priority control contaminants for sewage sludge in China because they have consistently high-risk quotient (RQ) values of 2.42–7.47, 1.28–3.16, 1.06–1.83 before and after sludge stabilization, respectively. More attention should be paid to BaA, BbF, benzo[k]fluoranthene (BkF), BaP, DahA, and indeno[1,2,3-cd]pyrene (IcdP) in Beijing; ANT, BaA, and BaP in Shanghai; and BaA and BaP in Guanghzou. Although the toxic equivalent quotient (TEQ) for PAHs met the limit concentration requirements of the national standard, the potential health risks due to long-term exposure to HMW PAHs cannot be ignored because the incremental lifetime cancer risk (ILCR) was consistently in the risk threshold range (>1 × 10−6). Some suggestions on enhanced treatment approaches and land use standards are proposed to further alleviate the risk from HMW PAHs.

Characterisation of polycyclic aromatic hydrocarbons associated with indoor PM0.1 and PM2.5 in Hanoi and implications for health risks

Polycyclic aromatic hydrocarbons (PAHs) associated with indoor PM pose a high risk to human health because of their toxicity. A total of 160 daily samples of indoor PM2.5 and PM0.1 were collected in Hanoi and analysed for 15 PAHs. In general, the concentrations of carcinogenic PAHs (car-PAHs) accounted for 21% ± 2%, 19.1% ± 2%, and 26% ± 3% of the concentrations of 15 PAHs in PM2.5, PM0.1-2.5, and PM0.1, respectively. Higher percentages of car-PAHs were found in smaller fractions (PM0.1), which can be easily deposited deep in the pulmonary regions of the human respiratory tract. The concentrations of 15 PAHs were higher in winter than in summer. The most abundant PAH species were naphthalene and phenanthrene, accounting for 11%–21% and 19%–23%, respectively. The PAH content in PM0.1 was almost twice as high as those in PM2.5 and PM0.1-2.5. Principal component analysis found that vehicle emissions and the combustion of biomass and coal were the main outdoor sources of PAHs, whereas indoor sources included cooking activities, the combustion of incense, scented candles, and domestic uses in houses. According to the results, 60%–90% of the PM0.1-bound BaP(eq) was deposited in the alveoli region, whereas 63%–75% of the PM2.5-bound BaP(eq) was deposited in head airways (HA), implying that most of the particles deposited in the HA region were PM0.1-2.5. The contributions of dibenz[a,h]anthracene and benzo[a]pyrene were dominant and contributed from 36% to 51% and 31%–50%, respectively, to the carcinogenic potential, whereas benzo[a]pyrene contributed from 30% to 49% to the mutagenic potential for both size fractions. The incremental lifetime cancer risk, simulated by Monte Carlo simulation, was within the limits set by the US EPA, indicating an acceptable risk for the occupants. These results provide an additional scientific basis for protecting human health from exposure to indoor PAHs.

Distribution, Sources, and Health Risk of Polycyclic Aromatic Hydrocarbons in Farmland Soil of Helan, China

With the development of industry and agriculture, polycyclic aromatic hydrocarbons (PAHs) in the agricultural sector have gradually increased to different degrees, leading to an escalation in environmental pollution. In turn, this escalation has presented a significant possibility of endangering agricultural practices on farmland and has had a serious impact on regional sustainable development. Therefore, a total of 117 samples of soil were gathered to research the pollution level, distribution, sources, and health risk of PAHs in Helan farmland soils. A reference was used for the identification and quantification of PAH content using high-performance liquid chromatography (HPLC) with an ultraviolet detector, and their spatial distribution was analyzed utilizing the Arc Geographic Information System (ArcGIS). The source of PAHs was analyzed by absolute principal component scores/multiple linear regression (APCS-MLR). The lifetime cancer risk increment model and Monte Carlo sensitivity analysis were used to assess the potential health hazards to humans associated with PAHs in soil. Within the current study area, PAHs were higher in the northwest. The results showed that the total content of PAHs in Helan farmland soil ranged from 17.82 to 1544.73 ng·g−1 with a mean of 408.18 ng·g−1, which indicated the middle degree of pollution in farmland soil. The verification results of the APCS-MLR model showed that the correlation coefficient between the measured values and the predicted values ranged from 0.661 to 0.984, which suggested that the APCS-MLR model demonstrated favorable suitability for conducting source analysis of PAHs in the soil within the study region. Based on the contribution of PAHs from each source, the main sources of PAHs in Helan farmland soil were the combustion source (biomass, diesel, and natural gas combustion) and the transportation source (gasoline for vehicles and traffic exhaust emissions). The health risks’ estimation showed that PAHs in farmland soil did not have potential health risks for adults but represented a carcinogenic risk for children via the main exposure pathway of ingestion with the mean intake of 1.28 × 10−5. Meanwhile, the carcinogenic risks (CRs) of dermal contact for the mean value of adults (9.32 × 10−7) was found to be higher than that for children (3.18 × 10−8). From the Monte Carlo simulation, the soil particle uptake rate was the most sensitive to the health risks of children and adults with risk probabilities of 26% and 52%, and the risk probabilities from body weight were −11% and −1%, whose negative value indicated that the increase in body weight could reduce the health risks to human. These findings could provide reference for the study of soil organic pollution in Helan farmland soil and contribute significantly to the preservation of the ecological environment, maintaining human health and safety, and promoting the sustainable development of regional farmland.

Sources, spatial-distributions and fluxes of PAH-contaminated dusts in the Athabasca oil sands region

Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) has increased in northern Alberta, Canada, due to industrial development in the Athabasca oil sands region (AOSR). However, the sources, summertime deposition fluxes and associated spatial patterns are poorly characterized, and the magnitude of contamination has not been directly contrasted with comparable measurements around large Canadian cities. PAHs were measured in Sphagnum moss collected from 30 bogs in the AOSR and compared with reference moss collected from various remote, rural and near-urban sites in Alberta and Ontario. At all 39 locations, strong correlations between depositional fluxes of PAHs and accumulation rates of ash (n = 117, r = 0.877, p < 0.001) implied that the main source of PAHs to moss was atmospheric deposition of particles. Average PAH concentrations at near-field AOSR sites (mean [SD], 62.4 [24.3] ng/g) were significantly higher than at far-field AOSR sites (44.9 [20.8] ng/g; p = 0.038) or the 7 reference sites in Alberta (20.6 [3.5] ng/g; p < 0.001). In fact, average PAH concentrations across the entire AOSR (7,850 km2) were approximately twice as high as in London, Ontario, or near petroleum upgrading and major traffic corridors in Edmonton, Alberta. A chemical mass balance model estimated that both delayed petcoke (33 % of PAHs) and fine tailings (38 % of PAHs) were the major sources of PAHs in the AOSR. Over the 2015 summer growing season, we estimate that 101–110 kg of PAHs (on 14,300–17,300 tonnes of PAH-containing dusts) were deposited to the AOSR within a 50 km radius of surface mining. Given that the highest PAH deposition was to the northern quadrant of the AOSR, which includes the First Nations community of Fort MacKay, further dust control measures should be considered to protect human and environmental health in the region.

Wet deposition of polycyclic aromatic hydrocarbons in a remote area of Central South China from 2014 to 2017

AbstractIn recent years, there has been a notable increase in the consumption of fossil energy, leading to a significant rise in environmental pollution, particularly in China due to its rapid development. This has resulted in the frequent occurrence of large‐scale fog and haze weather, highlighting the urgent need for environmental protection measures. To gain insights into the atmospheric conditions in China, an analysis was conducted on the wet deposition of polycyclic aromatic hydrocarbons (PAHs) in a remote region of Central South China from 2014 to 2017. The study revealed that the average concentrations and peak values of Ʃ16PAHs in 2014 and 2015 were considerably higher than those observed in 2016 and 2017. Furthermore, it was found that five‐ring PAH species were the predominant components during 2014 and 2015, indicating a shift in the main sources of PAHs. The peaks of Ʃ16PAHs were predominantly detected in samples collected during light rain in the winter, specifically on days without heavy rainfall. This can be attributed to the absence of heavy rain, which would otherwise reduce the concentration of air pollutants. Consequently, contaminants accumulated in the air are easily enriched in rainwater. The concentrations of Ʃ15Alkyl‐PAHs also exhibited a significant correlation with the number of rainfall days. Notably, a much higher annual average concentration of Ʃ15Alkyl‐PAHs was observed in 2017, which experienced fewer rainfall days. Coal combustion, petroleum sources, and vehicular emissions accounted for 58%, 12%, and 30% of the PAHs in the air, respectively. Despite improvements in air quality in China since 2016, it is crucial to address the elevated concentrations of PAHs in the atmosphere, particularly under adverse meteorological conditions characterized by reduced rainfall.

Distribution, composition and risk assessment of hydrocarbon residue in surficial sediments of El-Dakhla, El-Kharga and El-Farafra oases, Egypt.

This work examined the polycyclic aromatic hydrocarbons (PAHs) and n-alkanes quantities, sources, and hazards in sediments collected from the Egyptian Western Desert Oases namely: Dakhla, Kharga and Farafra oases. The n-alkane (C9-C20) residue concentrations have ranged from 0.66 to 2417.91 µg/g recorded for the three Oases. On the other hand, the total n-alkane ranged from 448.54 µg/g to 8442.60 µg/g. Higher carbon preference index (CPI) values (> 1.0) proposed that the natural sources could be the main contributor to n-alkanes in the Oases sediment. GC-MS/MS (selected reaction monitoring (SRM) method) was used for the determination of the ΣPAHs concentrations in the studied sediments. The ΣPAHs concentrations (ng/g, dry weight) in the studied three Oases varied from 10.18 to 790.14, 10.55 to 667.72, and from 38.27 to 362.77 for the Kharga, Dakhla and Farafra Oases, respectively. The higher molecular weight PAHs were the most abundant compounds in the collected samples. Assessing potential ecological and human health issues highlighted serious dangers for living things and people. All the investigated PAHs had cancer risk values between 1.43 × 10-4 and 1.64 × 10-1, this finding suggests that PAHs in the samples under study pose a moderate risk of cancer. The main sources of PAHs in this study are biomass, natural gas, and gasoline/diesel burning emissions.

Contamination and source-specific health risk assessment of polycyclic aromatic hydrocarbons in soil from a mega iron and steel site in China

The iron and steel industry has always been a key and difficult point of environmental pollution control. In the present study, 493, 175, 153, 72, and 42 soil samples were collected from the soil depths of 0–0.5, 0.5–2, 2–3, 3–4, and 4–5 m (herein called the layers) of the Shougang Steel site, respectively. Compared with the evaluation criteria, the Shougang Steel surface soil was severely polluted by polycyclic aromatic hydrocarbons (PAHs). Inverse distance-weighted interpolation and the Kruskal-Wallis H test revealed that the soil PAH pollution in the iron-making area, especially the coking area, was severer than those in other areas. The PAH concentrations first decreased, and then, increased with the increase of depth. With the increase in depth, the contributions of 2- and 3-ring PAHs increased, while those of 4-, 5-, and 6-ring PAHs decreased. The bivariate local indicators of spatial association (LISA) analysis was used to identify the areas prone to soil PAH pollution due to atmospheric deposition of industrial waste gas and traffic emissions. The method could be used to analyze the impact of anthropogenic activities on soil's PAH pollution for other contaminated sites. Three main pollution sources of soil PAHs, the backfill source, the combustion of coal, and the traffic emissions, were identified based upon three diagnostic ratios, positive matrix factorization and the bivariate LISA analysis, and accounted for 53.8%, 23.5%, and 22.7%, respectively. The combination of bivariate LISA analysis and other source analysis methods could improve the accuracy of source analysis. Benzo[a]pyrene contributed the most to the total health risk among sixteen PAHs. The health risks related to the three pollution sources decreased in the order of backfill sources > coal combustion > traffic emissions. The incremental life-time carcinogenic risks were all below 10−4, indicating negligible or acceptable risks.

A century-long record of polycyclic aromatic hydrocarbon deposition in the Old Yellow River Estuary, China

Polycyclic aromatic hydrocarbons (PAHs) are potential geochemical indicators for assessing the impact of human activities and can be used to reconstruct historical human activities. This study collected a 108 cm sediment core from the 5th lobe of the Yellow River Delta for the first time and analyzed the historical distribution characteristics of PAHs in this area. The results showed that the sedimentation history of the core was from 1908 to 2014. The average value of PAHs was 28.93 ng/g. Biomass and coal combustion sources were the main sources of PAHs in the low-value areas, while oil spill sources were the main sources in the significantly higher PAHs areas in the 1960s, mid-1980s, late 1990s, and late 2010s, which was consistent with the development history of Shengli Oilfield. Compared with global estuaries, the historical industrial activity intensity in this area was weaker.