Combustion-derived Polycyclic Aromatic Hydrocarbons Research Articles

Pliocene Coal Geochemistry: Palaeovegetation and Palaeoclimate Distribution in Berau Basin, Indonesia

We investigated the distributions and concentrations of plant-derived aliphatic-aromatic biomarkers in the Pliocene coal seam from the Pliocene Sajau Formation (CSF) in Berau Basin, Indonesia. In all coal samples, the presence of these components is abundant and varied, reflecting the diversity of paleoflora species and ancient climate variations during coal sedimentation. The distribution of aromatic hydrocarbons was detected, including 1,2,7-Trimethylnaphthalene (TMN), 1,6,7-TMN, and 1,2,5-TMN, cadalene, retene, 1-methylphenanthrene (M.P.), 3-MP, Phenantherene, 1,2,-dimethylphenanthrene (DMP), 2,6-DMP, 2,7-DMP, 6-isopropyl-1-isohexyl-2-methylnaphthalene, and other polycyclic aromatic hydrocarbons (PAHs)—saturated biomarkers including oleanane, des- A-oleanane, bicadinanes, and C29 ααα 20R sterane. The distribution of higher-plant biomarkers indicated that gymnosperms relatively dominated the Lower part of CSF. In contrast, the upper part of CSF showed an angiosperm-dominated higher plant terrigenous organic matter. The most charred coal in the Lower part of CSF is predominantly composed of combustion-derived PAHs, such as Benzo[a] anthracene, fluoranthene, and benzofluoranthenes. We show the cold-warm-hot climate conditions in the Pliocene in the Berau Basin by clear evidence of the distribution of biomarkers and spore-pollen.

Organic matter input, paleovegetation and paleoclimate of Upper Cretaceous lignite from Maiganga coalfield, Upper Benue Trough, Nigeria: Insights from biomarkers and stable isotopes

Upper Cretaceous Gombe Formation coals from Maiganga coalfield, Upper Benue Trough, Nigeria were investigated to evaluate the thermal maturity, organic matter input, paleovegetation, paleoclimate, and depositional environment using bulk and molecular geochemical techniques. Vitrinite reflectance (<0.40 %Ro) and biomarker maturity indicators (C31 homohopane 22S/(22S + 22R) < 0.3; 16(H) β/(β+α) phyllocladane <0.5; MPI-1 < 0.5; MPR <2.65) generally signify low thermal maturity. Source-related aliphatic and aromatic hydrocarbon ratios indicate that the coals are derived mainly from terrestrial organic matter but with considerable input from marine algal organic matter. The higher abundance of diterpenoids over triterpenoids and sesquiterpenoids suggests a prevailing contribution of gymnosperms to the Maiganga paleoflora. This is corroborated by the relatively heavier carbon isotopic composition (δ13C = −25.9‰ to −25.0‰) and low angiosperm/gymnosperm ratios. A new proxy, the polycyclic aromatic hydrocarbon ratio (PAHr) which is calculated from PAHr = (phenanthrene + pyrene + fluoranthene + perylene)/(phenanthrene + pyrene + fluoranthene + perylene + retene + cadalene), was proposed to evaluate the abundance and origin of combustion-derived polycyclic aromatic hydrocarbons (PAHs). The mostly high (>0.9) PAHr values for the coals are characteristic of a pyrogenic/combustion origin. Combustion-derived PAHs are abundant in the coals and their ratios indicate a mixed petrogenic/pyrogenic to dominantly pyrogenic origin. However, the high proportion of unburnt organic matter and low abundance of 7-ring PAHs such as coronene indicates limited, high-temperature wildfires. The coronene index values suggest burning temperature in the 700–1000 °C range, which is consistent with the estimated high pO2 of ∼26.5% in the Maastrichtian. n-Alkane proxies (Pwax, Paq, n-C23/n-C29, n-C27/n-C31, etc.) and hydrogen isotope ratios (−117‰ to −112‰) are suggestive of humid paleoclimate with frequent dry periods and lower paleopeat water levels. Moderately high pristane/phytane ratios (2.0–4.8) indicate deposition under sub-oxic to oxic freshwater settings. Additionally, low total sulphur content (0.29–0.90) and dibenzothiophene/phenanthrene ratios (0.05–0.17) imply peat accumulation in lacustrine-swamp to fluvial/deltaic depositional environments with minor post-depositional marine influence.

Paleowildfire at the end-Triassic mass extinction: Smoke or fire?

Polycyclic Aromatic Hydrocarbons (PAHs) are routinely used as proxies for wildfire in geological sediments associated with large igneous province (LIP) driven CO 2 increases and mass extinction events. One example is the end-Triassic mass extinction event (ETE) driven by Earth's most laterally extensive LIP, the Central Atlantic Magmatic Province (CAMP). However, many PAH records often lack critical information including identifying specific source(s) of PAHs (e.g., pyrogenic vs. petrogenic), intensity of paleowildfire events, whether PAHs represent predominant smoke signals that can travel substantial distance from the burn origin, and if evidence of PAH as markers for soil erosion exists. To better understand ETE wildfire events, a detailed evaluation of PAH distributions from the Italcementi section in the Lombardy Basin, Italy covering the latest Rhaetian was undertaken. We report the best evidence of wildfire activity occurs above the initial carbon isotope excursion (CIE) which is routinely used to chemostratigraphically correlate between ETE sections, rather than within the initial CIE as evidenced at other sections. This wildfire event was intense, short-lived, and occurred during a calcification crisis and δ 13 C org anomaly, thereby linking terrestrial and marine ecosystem stress. Evidence of a more prolonged but less intense wildfire event and/or evidence for smoke signals takes place above this interval before the onset of a second calcification crisis. By comparing PAH records from Italy, Greenland, Poland, the UK, and China, during the ETE, few sections show evidence for intense (i.e., higher-temperature) wildfire activity during the initial CIE. However, these investigated PAH records show prolonged increases in the low-molecular-weight (LMW) combustion-derived PAH phenanthrene . We interpret this to represent widespread (and possibly more intense) wildfire activity further from the deposition sites, since LMW combustion-derived PAHs are the major PAHs in smoke aerosols that can travel vast distances, and/or less intense wildfire activity that characteristically produce LMW combustion-derived PAHs. In comparing PAH data, we find widespread wildfire activity across multiple basins supporting wildfire activity was an important ecological stressor in the terrestrial realm during the ETE. • Polycyclic aromatic hydrocarbons in the end-Triassic extinction show two fire events. • Global polycyclic aromatic hydrocarbon comparisons support widespread fire activity. • End-Triassic extinction wildfire events had different intensities. • Polycyclic aromatic hydrocarbon ratios support conifer burning. • Carbon isotope excursions not associated with wildfire events in Northern Italy.

Occurrence and preservation of primary organic matter in a hybrid unconventional reservoir: Montney Formation, Western Canada Sedimentary Basin

The Lower Triassic Montney Formation of the Western Canada Sedimentary Basin (WCSB) is a world-class unconventional hydrocarbon resource in North America. It was deposited on the northwestern margin of Pangaea at mid-latitudes in an arid climate and after major mass extinction at the Late Permian-Triassic boundary. Despite decades of exploration and economic importance, the origin of organic matter and source of accumulated hydrocarbons is not well understood. The Montney Formation is primarily composed of dolomitic siltstone with a mean total organic carbon (TOC) content of ≤1 wt%. In this study, we re-examined samples from an Alberta Geological Survey (AGS) data release in 2010 on Montney Formation organic petrography and expand the sampling and analysis to further investigate organic matter type, thermal maturity, and possible internal hydrocarbon source intervals within the Montney Formation as well as organic matter preservation and depositional environment by integrating programmed pyrolysis, organic petrography, and molecular geochemistry.Organic petrography and molecular geochemistry show that millimeter to centimeter thick mudstone intervals with TOC ≤ 1 wt%, are dominantly comprised of Type II marine kerogen (Prasinophyte and Tasmanites) with minimal terrigenous organic matter. The presence of these organic-rich mudstone beds in central and western Alberta reveals intra-formational sources of hydrocarbons within the Montney Formation, in addition to hydrocarbons sourced from overlying organic-rich source rocks (i.e., Triassic Doig and Jurassic Gordondale). These results confirm that the Montney Formation can be considered as a hybrid unconventional hydrocarbon reservoir with an interbedded source and reservoir.Molecular geochemistry data suggest that photic zone euxinia (PZE) was favorable for the preservation of organic matter during deposition of the Montney Formation. However, in many instances, this only happened during very short periods similar to depositional conditions on the offshore present day Namibian shelf. Traces of terrigenous organic matter were able to reach the basin, likely in the form of inertinite and combustion-derived polycyclic aromatic hydrocarbons (PAHs). Although the results of this study show there are source rock intervals within the Montney Formation, a comprehensive organic petrography and geochemistry study on a series of full-length Montney cores throughout the basin will help to ascertain the major paleo depositional variation and their effect on organic matter preservation as well as hydrocarbon source intervals and their contribution to WCSB petroleum systems.

Record of Middle Jurassic wildfire and its incidental mercury emissions in northern Qaidam Basin, China: Evidence from the inertinite and mercury anomalies in coal

Inertinite in coals contains important information regarding the palaeo-wildfire history and can provide insights into its triggers and relationship with the evolution of local ecosystems. However, such information in the Middle Jurassic coal is often overlooked, and the impacts of incidental mercury emission from wildfires on the mercury enrichment in coal are also underestimation. In this study, the organic petrology, geochemistry and palynology of coal seams from the coal-bearing member of Shimengou Formation in northern Qaidam Basin (NQB) were investigated. Results show that these coal seams generally contain abundant records of palaeo-wildfire: inertinite and combustion-derived polycyclic aromatic hydrocarbons (PAHs). The high consistency of these two evidences confirms the existence of widespread wildfires during the late Middle Jurassic (Bathonian) in NQB. These widespread wildfires also indicate a high level of atmospheric oxygen concentration during this period. The overall low inertinite reflectance (avg. 1.27%) and low content of coronene in coal seams indicate that these wildfires were dominated by ground and surface fire with some small-scale crown fires. These frequent wildfires under the overall humid climate are attributed to the sufficient atmospheric oxygen, fuel and intermittent dry season. The co-occurrence of wildfires records and mercury anomaly in coal seams suggests that incidental mercury emissions from wildfires enhanced mercury input in the peatlands, which is the direct trigger for mercury anomaly in the coal from the Shimengou Formation in NQB. This study not only revealed the characteristics and causes of the widespread wildfires during the late Middle Jurassic in NQB, but also provides a new insight into the abnormal enrichment of mercury in coal.

Aromatic hydrocarbon signatures of the late Miocene-early Pliocene in the Yinggehai Basin, South China Sea: Implications for climate variations

Aromatic hydrocarbons in 36 shales from the late Miocene-early Pliocene strata of the Yinggehai Basin in the South China Sea were investigated. Various higher plant-derived aromatic hydrocarbons were identified, including cadalene, retene, 1,2,7-trimethylnaphthalene, 1-methylphenanthrene (MP), 1,7-dimethylphenanthrene (DMP), 6-isopropyl-1-isohexyl-2-methylnaphthalene, and other polycyclic aromatic hydrocarbons (PAHs). Higher plant parameters suggest that the relative abundance of terrigenous organic matter in the early Pliocene was lower than in the angiosperm-dominated late Miocene Huangliu Formation. Various plant parameters including retene/(retene + cadalene), 1-MP/9-MP, 1,7-DMP/(1,3- + 3,9- + 2,10 + 3,10-DMP), and the higher plant index, indicate that gymnosperms made a larger contribution to the organic matter when the lower Yinggehai Formation was deposited during the early Pliocene. Combustion-derived PAHs, including fluoranthene, benzo[a]anthracene, benzofluoranthenes and coronene, predominate over petrogenic PAHs in the lower Yinggehai Formation and the upper Meishan Formation, indicating that there were more wildfires during deposition of these units compared to the Huangliu Formation. In contrast, there is a mixed input of combustion-derived and petrogenic PAHs in the Huangliu Formation. As also supported by higher abundances of Pinus in palynological records, the combustion-derived PAHs and the gymnosperm/angiosperm parameters provide unequivocal evidence for a cooling climate from the late Miocene to the early Pliocene in the South China Sea.

Insights into the day-night sources and optical properties of coastal organic aerosols in southern China

Organic aerosols (OAs) in particulate matter with an aerodynamic diameter of smaller than 2.5 μm (PM2.5) can affect the atmospheric radiation balance through varying molecular structure and light absorption of the aerosols. In this study, daytime and nighttime PM2.5 mass, and contents of OA including nitrated aromatic compounds (NACs), polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and hopanes were measured from April 11th to May 15th, 2017, at the coastal Sanya, China. The average concentration of 18 total quantified PAHs (∑PAHs) was 2.08 ± 1.13 ng·m−3, which was 2.8 and 12 times higher than that of ∑NACs and hopanes, while was 7.5 times lower that of n-alkanes. Combustion-derived PAHs contributed 74% to the ∑PAHs. This finding, in addition to a high benzo[a]pyrene/(benzo[a]pyrene+benzo[e]pyrene) ratio, indicates that the PAHs mainly derived from fresh fuel combustion during the sampling periods. Furthermore, dramatic day-night differences were observed in the loadings of total NACs, PAHs, and n-alkanes, which had a high coefficient of divergence values of 0.67, 0.47, and 0.32, respectively. Moreover, hopanes exhibited similar variation as well. The proportion of dimethyl-nitrophenol (DM-NP), dinitrophenol (DNP), and nitrosalicylic acid (NSA) in PM2.5 were higher in the daytime than at nighttime, suggesting the co-influence of primary emissions and secondary formation related to biomass combustion. The positive matrix factorization (PMF) model revealed that motor vehicle and biomass burning emissions were the two main pollution sources in the daytime, contributing 51.7% and 24.6%, respectively, of the total quantified OAs. The proportion of industrial coal combustion emissions was higher at nighttime (20.6%) than in daytime (10%). Both the PAHs and NACs displayed light absorbing capacities among OAs compounds over Sanya City, and thus their influence on solar radiation must be considered in the future control policies.

Seaweed as bioindicators of organic micropollutants polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs).

This study highlights the role of seaweed as important indicators of pollutants as they respond immediately to change in water chemistry and have high survival capabilities. Concentration and risk assessment of 13 polycyclic aromatic hydrocarbons (PAHs), as well as 20 organochlorine pesticides (OCPs), were examined in the seaweed from El-Mex Bay, Mediterranean Sea during spring and autumn seasons. The green alga Ulva compressa had a maximum ability to accumulate both PAHs and OCPs. In general, the content of the tested micropollutants in the collected seaweed is correlated to their species, morphology, concentration, and nature of pollutant. Naphthalene (NAP) and benzo a pyrene were the predominant polycyclic aromatic hydrocarbons in all species with mean concentrations of 68.57 and 56.14 ng g−1, respectively. The results of the current study showed that the contribution of the different fractions of PAHs from the total concentration was as follows: fossil-fuel derived polycyclic aromatic hydrocarbons (∑PAHF; 49.32%) > combustion-derived polycyclic aromatic hydrocarbons (PAHCOMB; 30.83%) > carcinogenic fractions (PAHCARC; 19.86%). A maximum PAHCARC (30.38%) was recorded in Ulva fasciata. For OCPs, the presence of 1,1-dichloro-2, 2-bis (4-chlorophenyl) ethane (DDD) (ND-27.8 ng g−1) rather than DDT; 1,1,1-trichloro-2, 2-bis (4-chlorophenyl) ethane was an indication for biotransformation involving the reductive dichlorination of DDT to more recalcitrant and toxic DDD. Endrin ketone has the highest mean hazard quotient (0.376). The cancer risk values of most PAHs and OCPs were in the range from 10−4 to 10−3 recommending precautionary measures. The results explained that the present algal species play a vital role in the uptake of organic pollutants and act as biomarkers for micropollutants in the ecosystem.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-022-18634-z.

Biomarker signatures of Upper Cretaceous Latrobe Group petroleum source rocks, Gippsland Basin, Australia: Distribution and geological significance of aromatic hydrocarbons

Aromatic hydrocarbons extracted from Upper Cretaceous (Maastrichtian and Campanian) Latrobe Group coaly shales and shales from the Gippsland Basin were investigated by gas chromatography–mass spectrometry. A variety of 2-ring to 6-ring aromatic hydrocarbons were identified, including both higher-plant-derived and combustion-derived polycyclic aromatic hydrocarbons (PAHs). These aromatic compounds indicate that the Upper Cretaceous coaly shales and shales were deposited in a fluvial/deltaic environment with significant higher plant input and are at a relatively low thermal maturity stage. Higher plant parameters and angiosperm/gymnosperm indices based on aromatic components suggest that higher land plants, including both angiosperms and gymnosperms, were an important part of the palaeovegetation in the Upper Cretaceous. The aromatic angiosperm/gymnosperm index that includes chrysene- and picene-type PAHs is not as reliable for evaluation of relative angiosperm and gymnosperm contributions as the aliphatic indices due to input of combustion-derived PAHs and the complexity of burning conditions altering the relative contributions. However, combustion-derived PAHs and aromatic angiosperm/gymnosperm indices supplement the information from aliphatic hydrocarbons and provide further evidence to support the hypothesis that palaeoclimate cooled from the Campanian to the Maastrichtian.

Characteristics of polycyclic aromatic hydrocarbons components in fine particle during heavy polluting phase of each season in urban Beijing

Beijing experienced a period of severe atmospheric particulate pollution from 2015 to 2016. In order to acquire the characteristics of polycyclic aromatic hydrocarbons (PAHs) under heavy polluting status, one year sampling campaign was carried out. We selected PM2.5 samples which had the highest concentrations or suffered serious haze-fog weathers in each month. Through the analysis of data from heavily polluting phase, the mean concentrations of PM2.5 and PAHs in winter (369.63 μg m−3 and 223.60 ng m−3) were obviously higher than that in other seasons. The concentration of Σ16PAHs ranged from 3.22 to 297.01 ng m−3, with a mean value of 77.48 ng m−3. In winter, 4-ring PAH congeners (52.33%) contributed the most in PM2.5, followed by 5-rings (27.05%), 6-rings (11.55%) and 2∼3-rings (9.06%). Summertime measurements showed the highest decline in PAHs concentrations for 3∼5-ring congeners. The diagnostic ratios and PCA analysis manifest that vehicle and combustion emission were major sources and totally occupied 88.57% under heavy polluting stage. Moreover, exponential relationship between LWM/HWM (light/high weight molecule-PAHs) and combustion-derived PAHs, as well as linear relationship between BghiP and ∑PAHs verified that the pollution sources mentioned above affected local atmosphere environment as major sources. The highest total BaP equivalent concentration suggested that toxicity potency under heavy polluting phase was mainly attributed to 5-ring PAHs. Through analysis of carcinogenic-PAHs, potency risk to adults was significantly higher than that to children. BaP, BbF and DahA, which belong to 5-ring congeners, contributed the highest potency carcinogenic risk. BbF in winter, BaP in spring and winter may cause potential risk to local residents.

Organic geochemical and palynological evidence for Holocene natural and anthropogenic environmental change at Lake Dojran (Macedonia/Greece)

In this study, we present lipid biomarker and palynological data for a sediment core from Lake Dojran (Macedonia/Greece), which covers the entire Holocene period. We analyzed vascular plant-derived n-alkanes, combustion-derived polycyclic aromatic hydrocarbons (PAHs), fecal steroids, and bacterial and archaeal glycerol dialkyl glycerol tetraether (GDGT) lipids in concert with microcharcoal and pollen assemblages to reconstruct climatic, environmental, and human impact in the Dojran catchment and the greater Dojran area. Overall, our results suggest a relationship between anthropogenic activity and environmental/climatic change since increased human impact corresponds to phases of higher humidity and high lake levels at Lake Dojran. During the early Holocene, the record reveals increasing temperatures and humidity and concurrent increasing vegetation cover and runoff/soil erosion, respectively. Following a thermal maximum during the middle early Holocene, temperatures decrease gradually until present. The middle-Holocene at Lake Dojran is characterized by relatively stable environmental conditions followed by greater climatic instability and strong anthropogenic overprint during the late-Holocene. The fecal stanol record reveals phases of increased human impact during the early Bronze Age, the late Bonze/early Iron Age, and the Middle Ages. A phase of low stanol and PAH concentrations from the late Iron Age until the early Middle Ages is either related to ecosystem changes and/or changes in settlement pattern since concurrent pollen data indicate intensified land use. Human impact re-intensified during the Middle Ages with some variability probably related to climatic variations of the ‘Medieval Warm Period’ and the ‘Little Ice Age’.

Polycyclic aromatic hydrocarbons (PAHs) in atmospheric PM2.5 around 2013 Asian Youth Games period in Nanjing

Eighteen polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected near the Nanjing Olympic Sports Center across the Asian Youth Games (AYG) period (from August 2 to August 28, 2013) were analyzed using GC-MS. Their levels, sources and health risks to human were discussed. Results showed that the total concentrations of PAHs in PM2.5 were 9.43, 7.21 and 8.83ngm−3 for pre- (August 3–15), during- (August 16–24) and post- (August 25–28) AYG periods, respectively. They were dominated by 5-ring and 6-ring PAHs. Total PAHs concentrations in PM2.5 during AYG period decreased by 24%, when compared with those for pre-AYG period. For combustion-derived PAHs and carcinogenic PAHs, they decreased by 26% and 21%, respectively. It implied that the pollution control measures implemented during the AYG can effectively reduce the emission of PAHs from various sources. The poor correlations between PAHs and meteorological parameters also favored that the variations of PAHs were raised by the changes of emission sources. Diagnostic ratios and principal component analysis revealed that vehicle emission and coal combustion were the predominant contributors, with minimal effects from biomass burning and petroleum. The health risks for human exposed to PAHs in PM2.5 were quantitatively assessed by BaP equivalent concentration (BaPeq) and the incremental lifetime cancer risk (ILCR). The estimated ILCR value of PAHs during the AYG periods decreased by 23% and 27% for children and adults when compared with those for the pre-AYG, respectively. It indicated that the pollution control measures reduced the risks of PAHs to sportsmen or human gathered around the Olympic Sport Center.

Polycyclic aromatic hydrocarbons (PAHs) and their derivatives (alkyl-PAHs, oxygenated-PAHs, nitrated-PAHs and azaarenes) in urban road dusts from Xi’an, Central China

Urban road dusts are carriers of polycyclic aromatic compounds (PACs) and are therefore considered to be a major source of contamination of other environmental compartments and a source of exposure to PACs for urban populations. We determined the occurrence, composition pattern and sources of several PACs (29 alkyl- and parent-PAHs, 15 oxygenated-PAHs (OPAHs), 4 azaarenes (AZAs), and 11 nitrated-PAHs (NPAHs)) in twenty urban road dusts and six suburban surface soils (0–5cm) from Xi’an, central China. The average concentrations of ∑29PAHs, ∑4AZAs, ∑15OPAHs, and ∑11NPAHs were 15767, 673, 4754, and 885ngg−1 in road dusts and 2067, 784, 854, and 118ngg−1 in surface soils, respectively. The concentrations of most individual PACs were higher in street dusts than suburban soils, particularly for PACs with molecular weight>192gmol−1. The enrichment factors of individual PACs were significantly positively correlated with log KOA and log KOW, indicating an increasing deposition and co-sorption of the PACs in urban dusts with decreasing volatility and increasing hydrophobicity. Significant correlations between the concentrations of individual and sum of PACs, carbon fractions (soot and char), and source-characteristic PACs (combustion-derived PAHs and retene, etc.), indicated that PAHs, OPAHs and AZAs were mostly directly emitted from combustion activities and had similar post-emission fates, but NPAHs were possibly more intensely photolyzed after deposition as well as being emitted from vehicle exhaust sources. The incremental lifetime cancer risk (ILCR) resulting from exposure to urban dust bound-PACs was higher than 10−6, indicating a non-negligible cancer risk to residents of Xi’an.

Polycyclic aromatic hydrocarbons (PAHs) in atmospheric PM2.5 and PM10 at a coal-based industrial city: Implication for PAH control at industrial agglomeration regions, China

Eighteen polycyclic aromatic hydrocarbons (PAHs) in PM2.5 and PM10 are identified and quantified at five sites of E'erduosi in 2005 by GC–MS. Total PAH concentrations in PM2.5 and PM10 are in the ranges of 0.58–145.01ngm−3 and 5.80–180.32ngm−3 for the five sites, decreasing as coal-chemical base site (ZGE)>heavy industrial site (QPJ)>residential site with heavy traffic (DS)>suburban site surrounded by grassland (HJQ)>background site (QGN) for both PM2.5 and PM10. PAH concentrations in the coal-chemical base site are 250 and 31.1 times of those in the background site. Flu, Pyr, Chr, BbF, BeP, IND and BghiP are abundant for the coal-chemical base site, totally accounting for 75% of the PAH concentrations. 4, 5 and 6 rings PAHs are dominant, accounting for 88.9–94.2% and 90.5–94.1% of PAHs in PM2.5 and PM10, respectively. Combustion-derived PAH concentrations cover 42%–84% and 75%–82% of PAHs in PM2.5 and PM10, indicating large amounts of combustion sources existed for them in E'erduosi. PAH compositions between PM2.5 and PM10 are quite different from each other for sites with few human activities (HJQ and QGN) by coefficient of divergence analysis. Results obtained from principal component analysis and diagnostic ratios indicate that coal combustion, vehicle emission, wood combustion and industrial processes are the main sources for PAHs in E'erduosi. According to BaP equivalent concentration, the potential health risk of PAHs in PM2.5 at the two industrial sites ZGE and QPJ are 537 and 460 times of those for the background site. And they are 4.3 and 3.7 times of those for the residential site. The potential PAH pollution in particles at other industrial agglomeration regions that occurred in China in recent years should be paid attention by the local government.

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) into Central Park Lake, New York city, over a century of deposition

Relative contributions of polycyclic aromatic hydrocarbons (PAHs) from combustion sources of wood, petroleum, and coal were computed in sediments from Central Park Lake in New York City (NY, USA) by chemical mass balance based on several reliable source indicators. These indicators are the ratio of retene to the sum of retene and chrysene, the ratio of 1,7-dimethylphenanthrene (DMP) to 1,7-DMP and 2,6-DMP, and the ratio of fluroanthene to fluroanthene and pyrene. The authors found that petroleum combustion-derived PAH fluxes generally followed the historical consumption data of New York State. Coal combustion-derived PAH flux peaked approximately in the late 1910s, remained at a relatively high level over the next 3 decades, then rapidly declined from the 1950s to the 1960s; according to historical New York State coal consumption data, however, there was a 2-peak trend, with peaks around the early 1920s and the mid-1940s. The 1940s peak was not observed in Central Park Lake, most likely because of the well-documented shift from coal to oil as the major residential heating fuel in New York City during the late 1930s. It was widely believed that the decreased PAH concentrations and fluxes in global sediments during the last century resulted from a major energy shift from coal to petroleum. The data, however, show that this shift occurred from 1945 through the 1960s and did not result in an obvious decline. The sharpest decrease, which occurred in the 1970s was not predominantly related to coal usage but rather was the result of multiple factors, including a decline in petroleum usage largely, the introduction of low sulfur-content fuel in New York City, and the introduction of emission-control technologies.

Composition and source identification of polycyclic aromatic hydrocarbons in mangrove sediments of Peninsular Malaysia: indication of anthropogenic input

This is a comprehensive study of the composition, origin and sources of specific polycyclic aromatic hydrocarbons (PAHs) in sediments of mangrove estuary in the western part of Peninsular Malaysia. Mangrove sediments were analyzed for 17 PAHs by gas chromatography–mass spectrometry. Total PAH concentrations in the sediments ranged from 20 to 112 ng/g on a dry-weight basis. High molecular weight PAHs were abundant in the sediments. Parent PAH ratios revealed that pyrogenic input has important contribution to the sedimentary PAHs. Ratios of alkylated PAHs indicate that the sedimentary PAHs were influenced by petrogenic PAHs, which implies that petrogenic input has contribution to the sedimentary PAHs but that it is not a major factor in distribution of PAHs within the estuary. Combustion-derived PAHs show a positive and very strong correlation with total PAHs (R 2 = 0.926, p < 0.05). Total methylphenanthrenes show very weak correlation with total PAHs (R 2 = 0.0928, p < 0.05). The PAH concentrations were found to increase with distance from the upstream of the estuary to the coastal area of the Straits of Malacca. For the assessment of sediment contamination using biological thresholds, none of the individual studied PAH compounds exceeded the values of the effect range low–effect range median guideline and the threshold effects level–probable effects level guideline. This study demonstrates that the sediments of the mangrove ecosystem facing the Straits of Malacca and Sumatra are influenced by anthropogenic PAH inputs as a result of human activities such as biomass burning, vehicle emissions and boating activities.

Application of multiple geochemical markers to investigate organic pollution in a dynamic coastal zone

Multiple geochemical markers, including aliphatic hydrocarbons (n-alkanes), linear alkylbenzenes (LABs), and polycyclic aromatic hydrocarbons (PAHs), were employed to relate sediment organic chemical pollution in the coastal zone off South China to socioeconomic development there. Concentrations of Σn-C(15-35) (n-alkanes with 15-35 carbon atoms), ΣLAB (sum of C(10) to C(13) LABs), and Σ(26) PAH (sum of 26 PAH compounds) ranged from 110 to 3,160, 11 to 160, and 26 to 600 ng/g, with medians of 730, 40, and 230 ng/g, respectively. Natural hydrocarbons were mainly derived from terrestrial higher plant waxes, and in minor amounts from aquatic plankton and bacteria. Compositions of LABs indicated that considerable amounts of poorly treated wastewater had been directly discharged or transported to the eastern and western coastal areas of Guangdong Province. In addition, anthropogenic hydrocarbons were derived largely from vehicular emissions and combustion of domestic coal and biomass and to a lesser extent from oil spills. Eastern and western coastal sediments contained higher levels of LABs but lower levels of PAHs than those of the Pearl River Estuary, a coastal area of the Pearl River Delta. This spatial pattern of organic pollution was consistent with chemical use patterns. The eastern and western regions of Guangdong Province are economically less developed than the Pearl River Delta region, where more domestic wastewater treatment plants have been built. However, greater amounts of energy are consumed in the latter region to produce more combustion-derived PAH contamination.

Hypomethylation of Dual Specificity Phosphatase 22 Promoter Correlates With Duration of Service in Firefighters and Is Inducible by Low-Dose Benzo[a]Pyrene

Firefighters (FFs) are chronically exposed to smoke and products of incomplete combustion, which frequently contain polycyclic aromatic hydrocarbons (PAHs). This study examined the possibility of an association between PAH-induced epigenetic alterations and occupational firefighting exposure. Promoter methylation was analyzed in four genes in blood DNA from 18 FFs and 20 non-FFs (controls). Jurkat and human normal prostate epithelial cells were treated with benzo[a]pyrene to ascertain the epigenetic effects of this type of agent. Firefighters had a higher prevalence of dual specificity phosphatase 22-promoter hypomethylation in blood DNA (P = 0.03) and the extent of hypomethylation correlated with duration of firefighting service (P = 0.04) but not with age. Benzo[a]pyrene reduced promoter methylation and increased gene expression of the same gene in Jurkat and normal prostate epithelial cells. Cumulative occupational exposure to combustion-derived PAHs during firefighting can cause epigenetic changes in promoters of specific genes.

Combustion-derived substances in deep basins of Puget Sound: Historical inputs from fossil fuel and biomass combustion

Reconstructions of 250 years historical inputs of two distinct types of black carbon (soot/graphitic black carbon (GBC) and char-BC) were conducted on sediment cores from two basins of the Puget Sound, WA. Signatures of polycyclic aromatic hydrocarbons (PAHs) were also used to support the historical reconstructions of BC to this system. Down-core maxima in GBC and combustion-derived PAHs occurred in the 1940s in the cores from the Puget Sound Main Basin, whereas in Hood Canal such peak was observed in the 1970s, showing basin-specific differences in inputs of combustion byproducts. This system showed relatively higher inputs from softwood combustion than the northeastern U.S. The historical variations in char-BC concentrations were consistent with shifts in climate indices, suggesting an influence of climate oscillations on wildfire events. Environmental loading of combustion byproducts thus appears as a complex function of urbanization, fuel usage, combustion technology, environmental policies, and climate conditions.

Polycyclic aromatic hydrocarbons in coastal sediments of southwest Taiwan: An appraisal of diagnostic ratios in source recognition

Fifty-seven surface sediment samples were collected from the coast of southwest Taiwan and analyzed for polycyclic aromatic hydrocarbons (PAHs). Concentrations of total PAHs (28 PAH compounds) ranged from 15 to 907 ng g −1 dry weight. Diagnostic ratios showed that PAHs in the sediments of the Gaoping estuary were predominantly of petroleum origin, whereas sediments from the Kaohsiung coast contained principally combustion-derived PAHs. Principal component analysis indicated that emissions from automobiles and coal burning were the main sources of combustion-derived PAHs. The relatively high ratios of perylene/penta-aromatic PAH isomers in sediments from the Tainan coast and some off-shore stations on the Kaohsiung coast suggest a significant diagenetic PAH contribution. The study shows that certain diagnostic ratios are useful and sensitive in delineating the distribution of PAHs from specific sources in southwest Taiwan. The phenanthrene/anthracene ratio is a better indicator than the methylphenanthrenes/phenanthrene ratio for tracing petrogenic PAHs, and the benzo( a)anthracene/chrysene and indeno(1,2,3- c, d)pyrene/benzo( g, h, i)perylene ratios are more specific than the benzo( a)pyrene/benzo( e)pyrene and benzo( b)fluoranthcene/benzo( k)fluoranthcene ratios in distinguishing PAHs from various pyrogenic sources.