Polycyclic Aromatic Hydrocarbons Diagnostic Ratios Research Articles

Polycyclic Aromatic Hydrocarbons Contamination and Quality of Locally Produced Crude Palm Oil in South-South Zone, Nigeria

Background: Oil palm, Elaeis guineensis Jacq is a perennial crop mainly cultivated for its vegetable oil. The fatty acid composition of crude palm oil (CPO) is mostly composed of palmitic, stearic oleic, and linoleic acids. Objectives: This study evaluated the quality of locally produced CPO from six states of South-South zone, Nigeria. Methods: The parameters of CPOs were characterized by specific gravity (SG), acid value (AV), percentage of free fatty acid (%FFA), and saponification value (SV) and peroxide value (PV). Polycyclic aromatic hydrocarbons (PAHs) in CPO were quantified using standard procedures, the related risk due to daily consumption of 25 g was characterized by lifetime cancer risk (LCR) and margin of exposure (MOE). Results: The study observed that the mean values of the parameters were 0.931 SG; 5.01 mgKOH g-1 AV; 2.28% FFA; 177.27 mgKOH g-1 SV and 29.65 meqO2 kg-1 PV. Apart from %FFA, the others did not meet the requirements recommended by the Codex Alimentarius Commission of the joint WHO/FAO. Diagnostic ratios of PAHs suggested a mixture of petrogenic and pyrogenic origins. The MOEs showed low health concern while 16PAH-LCR values which ranged from 2.48E-04 - 4.48E-04 were unacceptable. The screening value 0.003 was significantly (p> 0.05) lower than the computed total BaP equivalent (BaPeq) values indicating potential human health concerns. It is recommended that CPO processing and storage methods should be properly monitored to prevent quality reduction and contamination, which might have adverse effect on consumers.

The assessment of organic contaminants at a paint manufacturing site: implications for health risks and source identification

The daily variation of organic contaminants, both gaseous and associated with suspended particulate matter, was investigated within the National Company of Paintings estate in Lakhdaria, Algeria, spanning the period 2014-2015. The research emphasizes the chemical characterization of suspended particulate matter, analyzing a range of organic compounds, including n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and highly polar organics (HPOC), such as phthalate esters and heterocyclic compounds. Vapours of PAHs and polychlorobiphenyls (PCBs) were also analyzed. Low molecular weight compounds were primarily associated with the gas phase (2-ring PAHs, approximately 95%; 3-ring PAHs, around 70%), while high molecular weight congeners were mainly associated with the particle phase (6-ring PAHs, 55%). The concentrations of PCBs (ranging from 0.6 to 42 ng m-3) were higher than those reported in other cities in Algeria and Europe. The source reconciliation of organic contaminants through principal component analysis (PCA) demonstrated that the primary sources were petroleum combustion, industrial manufacturing, tobacco smoking, and vehicular traffic. The significance of tobacco smoke was further confirmed by the analysis of PAHs diagnostic ratios. The variations in diagnostic ratio rates between gaseous and particulate PAHs were attributed to distinct contributions from sources such as industrial processes. Health risks for workers exposed to PAHs and PCBs in PM10 were quantitatively assessed in terms of Benzo[a]pyrene equivalent concentration (BaPeq) and incremental lifetime cancer risk (ILCR). ILCR presents novel findings, showcasing heightened risks among workers exposed to specific PAHs within production areas, whereas that related to PCBs suggested a high potential health risk for laboratory workers.

Lichen biomonitoring to assess spatial variability, potential sources and human health risks of polycyclic aromatic hydrocarbons (PAHs) and airborne metal concentrations in Manchester (UK)

Airborne metals and organic pollutants are linked to severe human health impacts, i.e. affecting the nervous system and being associated with cancer. Airborne metals and polycyclic aromatic hydrocarbons (PAHs) in urban environments are derived from diverse sources, including combustion and industrial and vehicular emissions, posing a threat to air quality and subsequently human health. A lichen biomonitoring approach was used to assess spatial variability of airborne metals and PAHs, identify potential pollution sources and assess human health risks across the City of Manchester (UK). Metal concentrations recorded in lichen samples were highest within the city centre area and along the major road network, and lichen PAH profiles were dominated by 4-ring PAHs (189.82 ng g−1 in Xanthoria parietina), with 5- and 6-ring PAHs also contributing to the overall PAH profile. Cluster analysis and pollution index factor (PIF) calculations for lichen-derived metal concentrations suggested deteriorated air quality being primarily linked to vehicular emissions. Comparably, PAH diagnostic ratios identified vehicular sources as a primary cause of PAH pollution across Manchester. However, local more complex sources (e.g. industrial emissions) were further identified. Human health risk assessment found a “moderate” risk for adults and children by airborne potential harmful element (PHEs) concentrations, whereas PAH exposure in Manchester is potentially linked to 1455 (ILCR = 1.45 × 10−3) cancer cases (in 1,000,000). Findings of this study indicate that an easy-to-use lichen biomonitoring approach can aid to identify hotspots of impaired air quality and potential human health impacts by airborne metals and PAHs across an urban environment, particularly at locations that are not continuously covered by (non-)automated air quality measurement programmes.Graphical

History of organic pollution in montane lake Issyk-Kul, Kyrgyzstan, Central Asia, inferred from a sediment core

In arid regions, montane lakes are valuable water sources and play important ecological roles. However, recent human-induced inputs of organic pollutants are threatening lake ecology in such regions and becoming a matter of great concern. To investigate pollutant histories and sources, we measured polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in a dated sediment core that spans the last ∼350 years, from montane Lake Issyk-Kul (Kyrgyzstan, Central Asia). Results showed that organic pollutants were delivered to Lake Issyk-Kul in four stages and that their concentrations increased from Stage I (∼1670–1800 CE) to Stage IV (∼2000–2010 CE). Furthermore, we tracked the sources of sedimented PAHs using their ratios combined with n-alkanes data. Ratios of PAHs Ant/(Ant + Phe), Flt/(Flt + Pyr) and Bap/BghiP indicated that inputs during Stage II (∼1800–1970 CE) and Stage III (∼1970–2000 CE) came mainly from high-temperature combustion of coal and vehicle emissions. PAHs in Stage I and Stage IV, however, were mainly derived from low-temperature combustion and petrogenic sources. Diagnostic PAH ratios, combined with the natural n-alkane ratio (NAR＜0) and unresolved complex mixtures (UCM), showed that the sources of PAHs in Stage I were mainly from erosion of bedrock and partly influenced by forest wildfires, different from the source during Stage IV, which was mainly from refined petroleum caused by accidental spills. Our assessment of the contamination history of the lake indicates that toxicity risk to the waterbody from sediment PAHs is low, but recent discharges arising from traffic deserve attention.

Characterization of PAHs bound to ambient ultrafine particles around runways at an international airport

The impact of airport activities on air quality, is not sufficiently documented. In order to better understand the magnitude and properly assess the sources of emissions in the sector, it is necessary to establish databases with real data on those pollutants that could have the greatest impact on both health and the environment.Particulate matter (PM), especially ultrafine particles, are a research priority, not only because of its physical properties, but also because of its ability to bind highly toxic compounds such as polycyclic aromatic hydrocarbons (PAHs).Samples of PM were collected in the ambient air around the runways at Barajas International Airport (Madrid, Spain) during October, November and December 2021. Samples were gathered using three different sampling systems and analysed to determine the concentration of PAHs bound to PM. A high-volume air sampler, a Berner low-pressure impactor, and an automated off-line sampler developed in-house were used. The agreement between the samplers was statistically verified from the PM and PAH results.The highest concentration of PM measured was 31 μg m−3, while the concentration of total PAH was 3 ng m−3, both comparable to those recorded in a semi-urban area of Madrid.The PAHs showed a similar profile to the particle size distribution, with a maximum in the 0.27–0.54 μm size range, being preferentially found in the submicron size fractions, with more than 84% and around 15–20% associated to UFPs.It was found that the ratio [PAHs(m)/PM(m)] was around 10–4 in the warmer period (October), whereas it more than doubled in the colder months (November–December). It is significant the shift in the relative distribution of compounds within these two periods, with a notable increase in the 5 and 6 ring proportions in the colder period. This increase was probably due to the additional contribution of other external sources, possibly thermal and related to combustion processes, as supported by the PAH diagnostic ratios.

Chemical characterization, source identification and potential health effects of PM2.5-bound non-polar organic compounds over a COALESCE network site - Bhopal, India

Year-long (2019) measurements of carbonaceous aerosols were performed at Bhopal, a regionally representative site as a part of the COALESCE (Carbonaceous Aerosol Emissions, Source apportionment and Climate Impacts) campaign. Aerosol-associated non-polar organic compounds (NPOCs) were analysed using thermal desorption (TD) Gas chromatography/Mass spectrometry (TD-GC/MS). The annual average of the total organic carbon (OC), elemental carbon (EC), and analysed PAHs (Polycyclic Aromatic Hydrocarbons), and n-alkanes were, 9.74 ± 9.47 μg m−3, 2.13 ± 3.12 μg m−3, 10.43 ± 5.49 ng m−3, and 114.93 ± 49.24 ng m−3, respectively. PAHs diagnostic ratios suggested emissions from petroleum, grass, wood, and coal combustion. Combustion derived PAHs (CombPAHs) accounted for 72.5 % of the total measured PAHs. During wintertime, based on Pyr/BaP ratio (∼0.6), gasoline exhaust emissions were higher compared to diesel exhaust emissions. The weak correlations between PAHs and meteorological parameters suggested that variations in PAH levels are primarily driven by alterations in emission sources. Total PAHs were correlated moderately with BrC (r2 = 0.60). The estimated lifetime lung cancer risk (LLCR) values on exposure to 16 USEPA priority PAHs (5 × 10−5) demonstrated that PAH levels in this region pose moderate health risks. Given observations from only campaign mode short-term measurements of NPOCs over India, this work provides a more comprehensive understanding of the concentrations, seasonal variations, and sources of n-alkanes and health risk associated with particle bound PAHs over the data-poor central Indian region.

Characterization and health risk assessment of PM2.5-bound polycyclic aromatic hydrocarbons in Yangon and Mandalay of Myanmar

To better understand the potential adverse health effects of atmospheric fine particles in the Southeast Asian developing countries, PM2.5 samples were collected at two urban sites in Yangon and Mandalay, representing coastal and inland cities in Myanmar, in winter and summer during 2016 and 2017. The concentrations of 21 polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were determined using a gas chromatography–mass spectrometry (GC–MS). The concentrations of PAHs in PM2.5 in Yangon and Mandalay ranged from 7.6 to 180 ng m−3, with an average of 72 ng m−3. The PAHs were significantly higher in winter than in summer, and significantly higher in Mandalay than in Yangon. The health risk analysis of PAHs, based on the toxic equivalent quantity (TEQ) calculation, and the incremental lifetime cancer risk (ILCR) assessment indicated that PM2.5 in Myanmar has significant health risks with higher health risks in Mandalay compared to Yangon. Diagnostic ratios of PAHs, correlation of PAHs with other species in PM2.5 and the positive matrix factorization (PMF) analysis showed that TEQ is strongly affected by biomass burning and vehicular emissions in Myanmar. Additionally, it was found that the aging degree of aerosols and air mass trajectories had great influences on the concentration and composition of PAHs in PM2.5 in Myanmar, thereby affecting the toxicity of PM2.5.

Determining the sources and distribution of polycyclic aromatic hydrocarbons in the soil of different oil fields at Basrah governorate, Iraq

The object of the research is polycyclic aromatic hydrocarbons (PAHs). For the purpose of determining the source and distribution of PAHs, soil samples from the 11 oil fields in the Basrah governorate (Seba, Safwan, Majnoon, Ratawi, Bergezia, Qurna1, Qurna2, Shuaaba, South and North Rumaila, and al Zubair) were taken at a depth of 0 to 20 cm. According to their molecular weight, they were separated into two main groupings. The first group of compounds consisted of six compounds: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, and anthracene. These light (low molecular weight) compounds have two to three fused aromatic rings. The first group includes nine chemicals: floranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b), benzo(k), benzo(a), benzo(a), indeno(1,2,3,c,d), and benzo(g,h,i)perylene. These heavy (high molecular weight) compounds included four or more fused aromatic rings. The PAHs compounds ranged in value from the lowest (0.16 ng/g dry weight of benzo(a)anthracene at station West Quarna1) to the highest (680 ng/g dry weight of benzo(g,h,i)perylene that emerged at station North Rumail). The total concentration of PAHs ranged from 77.67 ng/g in South Rumaila Field while highest concentration is 2284.27 ng/g in North Rumail. The PAHs compound has low and high molecular weight, their ratio of LMW/HMW (low molecular weight/high molecular weight) and phenanthrene/anthracene, fluoranthene/pyrene indicated that the source of PAHs was pyrogenic only. The PAH diagnostic ratios and principal component analysis (PCA) indicated that PAHs in soils essentially originated from emissions and combustion. This study gave a baseline on the source and distribution of these compounds in oil fields at Basrah governorate and can be used as a baseline for coming study in the future.

Anthropogenic emission controls organic aerosols at Gosan background site in the outflow from northeast Asia

Anthropogenic activities release substantial amounts of organic components into the atmosphere. In this study, eight groups of organic compounds such as polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, n-alkanes, fatty acids, fatty alcohols, phthalate esters, and lignin and resin acids were identified in the ambient aerosol samples collected from a regional background site in the Korean Climate Observatory at Gosan (KCOG), South Korea. The total identified organics were most abundant in winter (220 ± 60.3 ng m−3), followed by spring, autumn, and summer, with the predominance of n-fatty acids. All classes of aliphatic lipid components showed a significant positive correlation with fossil fuel-derived organic carbon (OC-FF) and biomass burning-derived organic carbon (OC-BB), indicating that they were abundantly emitted from anthropogenic sources such as fossil fuel combustion and biomass burning. The composition profiles and diagnostic ratios of PAHs indicate that they were largely derived from coal and/or biomass combustion in the continent. In contrast, hopanes are predominantly emitted from gasoline or diesel engines, particularly in the summer, from commercial ships. The high concentration of phthalates in the summer suggested that plastic emissions from the open ocean substantially contributed to the Gosan aerosols. The low ratios of unsaturated/saturated fatty acids indicate that Gosan organic aerosols were photochemically aged during atmospheric transport. The temporal and seasonal variations of organic species over KCOG provide crucial information on the emission strengths of different contributing sources in the East Asian outflow. Positive Matrix Factorization (PMF) results and 14C-based source apportionment studies demonstrated that anthropogenically derived organic aerosols largely contributed to the aerosol mass over KCOG. Thus, the East Asian continent might be the major source region for organic aerosols over the western North Pacific, except in the summer.

Occurrence, distribution and sources of petroleum contamination in reef-associated sediments of the Gulf of Mannar, India

The distribution of saturated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) was assessed in superficial sediment samples collected from Mandapam island groups, Gulf of Mannar, India. The hydrocarbon distribution pattern and the n-alkane indices (e.g., carbon preference index (CPI) and natural n-alkanes ratio (NAR)) were deployed to differentiate between the biogenic and anthropogenic sources. Petroleum pollution was indicated by the pristane/phytane ratio close to 1. Presence of a prominent unresolved complex mixture (UCM) as well as hopane concentrations further supported this assertion. The evaluation of petrogenic sources of contamination were also comprehended by various diagnostic ratios of PAHs. The sites associated with shipping activities, tourism, and located near the mainland and accessible portions of the islands exhibited high petroleum contamination. Correlation analysis underlines the significance of combining petroleum-specific marker compounds and diagnostic ratios to improve the assessment of human influence on marine ecosystems.

Integrative assessment of urban dust polycyclic aromatic hydrocarbons using ground and satellite data in Iran.

Recently, for quick urbanization and industrialization, pollutants, especially urban dust, have posed many threats to the human environment. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the main dangerous pollutants that are widespread, persistent, and carcinogenic. The present work aimed to investigate the contamination and sources of PAHs, as well as to assess the risk of cancer for 16 priority PAHs, in urban dust samples in Ahvaz, Isfahan, and Shiraz cities in Iran. We measured PAH concentrations by gas chromatography-mass spectrometry (GC-MS). The average concentrations of the 16 PAHs in Ahvaz, Isfahan, and Shiraz were 6215.11, 7611.03, and 7810.37 μg kg-1, respectively. The domination of low-molecular-weight (LMW) PAHs was observed in Ahvaz, while maximum contribution was observed for high-molecular-weight (HMW) PAHs in Esfahan and Shiraz. For PAHs' source identification, diagnostic ratio, correlation analysis, clustering, and positive matrix factorization (PMF) model were used. PAHs had a combustion (coal and wood, oil, fossil fuels) and gasoline/diesel engine emissions in all cities. Comparative studies suggest that the PAH compounds' level is higher in the research area than in other countries, except for China and India. Also, the pollution of urban dust PAHs has increased over time compared to previous studies in the same cities. The cancer risk from exposure to dust contaminated with PAHs was assessed using the Incremental Lifetime Cancer Risk (ILCR) model. According to the findings, a high risk of exposure to cancer was observed in Ahvaz, Isfahan, and Shiraz. However, compared to adults, children are at higher risk of cancer in their daily lives via dermal contact and unconscious ingestion. Based on the ILCR values, the risk of cancer is in the order of Shiraz > Isfahan > Ahvaz. To assess air pollutants and their effects on urban dust, TROPOMI onboard the Sentinel-5P data were used in the studied cities during 2018-2021. The results show that Ahvaz has different high levels of CO compared to the other 2 cities. Also, Isfahan has different high levels of NO2 compared to the other 2 cities, but Shiraz has different low levels of O3. According to satellite time series data, the trend of the Aerosol Absorbing Index (AAI) has been increasing, while there was a decreasing trend in AAI from the beginning of the COVID-19 pandemic until 12 months later. Therefore, the natural and anthropogenic sources of urban dust PAHs have been increasing in all studied cities. Our findings show that PAH compounds in urban dust pose a significant threat to human health. Therefore, strategic management and planning are vital in reducing urban dust pollution.

Occurrence, Sources, and Health Risks of Polycyclic Aromatic Hydrocarbons in Road Environments from Harbin, a Megacity of China.

To obtain a comprehensive understanding about that occurrence, sources, and effects on human health of polycyclic aromatic hydrocarbons (PAHs) in road environmental samples from Harbin, concentrations of 32 PAHs in road dust, green belt soil, and parking lot dust samples were quantified. The total PAH concentrations ranged from 0.95 to 40.7 μg/g and 0.39 to 43.9 μg/g in road dust and green belt soil, respectively, and were dominated by high molecular weight PAHs (HMW-PAHs). Despite the content of PAHs in arterial roads being higher, the composition profile of PAHs was hardly influenced by road types. For parking lot dust, the range of total PAH concentrations was 0.81-190 μg/g, and three-ring to five-ring PAHs produced the maximum contribution. Compared with surface parking lots (mean: 6.12 μg/g), higher total PAH concentrations were detected in underground parking lots (mean: 33.1 μg/g). The diagnostic ratios of PAHs showed that petroleum, petroleum combustion, and biomass/coal combustion were major sources of PAHs in the samples. Furthermore, according to the Incremental Lifetime Cancer Risk model, the cancer risks of three kinds of samples for adults and children were above the threshold (10-6). Overall, this study demonstrated that PAHs in the road environment of Harbin have a certain health impact on local citizens.

Past fire dynamics inferred from polycyclic aromatic hydrocarbons and monosaccharide anhydrides in a stalagmite from the archaeological site of Mayapan, Mexico

Abstract. Speleothems (cave stalagmites) contain inorganic and organic substances that can be used to infer past changes in local and regional paleoenvironmental conditions. Specific biomarkers can be employed to elucidate the history of past fires, caused by interactions among climate, regional hydrology, vegetation, humans, and fire activity. We conducted a simple solid–liquid extraction on pulverised carbonate samples to prepare them for analysis of 16 polycyclic aromatic hydrocarbons (PAHs) and three monosaccharide anhydrides (MAs). The preparation method requires only small samples (0.5–1.0 g); PAHs and MAs were measured by GC–MS and LC–HILIC–MS, respectively. Detection limits range from 0.05–2.1 ng for PAHs and 0.01–0.1 ng for MAs. We applied the method to 10 samples from a ∼ 400-year-old stalagmite from Cenote Ch'en Mul, at Mayapan (Mexico), the largest Postclassic Maya capital of the Yucatán Peninsula. We found a strong correlation (r = 0.75, p < 0.05) between the major MA (levoglucosan) and non-alkylated PAHs (Σ15). We investigated multiple diagnostic PAH and MA ratios and found that although not all were applicable as paleo-fire proxies, ratios that combine PAHs with MAs are promising tools for identifying different fire regimes and inferring the type of fuel burned. In the 1950s and 1960s, levoglucosan and Σ15 concentrations roughly doubled compared to other times in the last 400 years, suggesting greater fire activity at Mayapan during these two decades. The higher concentrations of fire markers may have been a consequence of land clearance at the site and exploration of the cave by Carnegie Institution archaeologists.

Polycyclic Aromatic Hydrocarbons from Domestic Solid Waste Incinerators in Nam Dinh Province, Northern Area of Vietnam: A Comprehensive Assessment of Emission, Source Markers and Human Health Risk.

A comprehensive research of the polycyclic aromatic hydrocarbons (PAHs) emission from domestic waste incinerators in northern areas of Vietnam, were investigated. Sixty-four samples from two domestic waste incinerators were collected and analyzed for PAHs. The PAHs concentrations in the samples were determined using gas chromatography coupled with mass spectrometry. In April, June, September, and November 2021, Σ16PAHs mean concentrations in chimney air samples were 970.9 ± 57.4, 1061.9 ± 49.8, 1070.7 ± 41.3 and 1136.1 ± 136.5µg m-3, respectively. The mean emission factors of Σ16PAHs were 7.5mg/kg. The mean percentages of low molecular weight PAHs were predominant in the analyzed air samples. The toxic equivalent quotient of samples ranged from 30.7 to 41.7mg/kg, whereas the incremental lifetime cancer risk exceeded 10- 3. This results implied a high level of concern with potentially negative health consequences. The four diagnostic ratios of PAHs were found and can be used for identification of sources markers from domestic waste incinerators.

Source apportionment of PM2.5 in Thailand's deep south by principal component analysis and impact of transboundary haze.

Atmospheric particulate matter smaller than 2.5 micron (PM2.5) was evaluated at four sites in the lower southern part of Thailand during 2019-2020 to understand the impact of PM2.5 transport from peatland fires in Indonesia on air quality during the southwest monsoon season. Mass concentration and chemical bound-PM, including carbon composition, e.g., organic carbon (OC) and elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), and inorganic elements, were analyzed. The PM2.5 emission sources were identified by principal components analysis (PCA). The average mass concentrations of PM2.5 in the normal period, which represents clean background air, from four sites was 3.5-5.1µg/m3, whereas during the haze period, it rose to 5.4-13.5µg/m3. During the haze period, both OC and EC were 3.5 times as high as in the normal period. The average total PAHs and BaP-TEQ of PM2.5 during the haze period were ~ 1.3-1.7 and ~ 1.2-1.9 times higher than those in the normal period. The K concentrations significantly increased during haze periods. SO42- dominated throughout the year. The effects of external sources, especially the transboundary haze from peatland fires, were significantly enhanced, because the background air in the study locations was generally clean. PCA indicated that vehicle emission, local biomass burning, and secondary particles played a key role during normal period, whereas open biomass burning dominated during the haze phenomena. This was consistent with the OC/EC and PAH diagnostic ratios. Backward trajectories confirmed that the sources of PM during the haze period were predominantly peatland fires in Sumatra, Indonesia, due to southwest wind.

ПОЛИЦИКЛИЧЕСКИЕ АРОМАТИЧЕСКИЕ УГЛЕВОДОРОДЫ И ЧАСТИЦЫ PM10, PM2,5, PM1,0 В АТМОСФЕРЕ ЮЖНОГО ПРИБАЙКАЛЬЯ

The study presents the data on concentrations of polycyclic aromatic hydrocarbons (PAHs), coarse (PM10, PM2.5) and submicron (PM1.0) particles in the atmosphere over the southern Baikal region at two monitoring stations (urban (Irkutsk) and rural (Listvyanka village)) in 2019-2022. Seasonal dynamics and high correlations between their concentrations are revealed. It was found out that PAHs are mainly sorbed on coarse particles in the atmosphere over Irkutsk and on submicron particles in Listvyanka. The total concentration of 21 PAHs varied at the stations from 1-3 ng/m3 in summer to 35-50 ng/m3 in winter, with an average annual value approximately 20 ng/m3. High concentrations in all seasons were determined for fluoranthene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, and phenanthrene. The calculated equivalent of aerosol toxicity in the atmosphere over Irkutsk increased from summer to winter with a growing contribution of benzo[a]pyrene exceeding maximum permissible concentration (MPC) by 8 times. The mass concentration during the year varied from 13 to 180 µg/m3 for PM10, from 4 to 121 µg/m3 for PM2.5, from 4 to 118 µg/m3 for PM1.0. Exceeding the MPC for PM2.5 by 1.1-3.4 times was recorded in Irkutsk from November to May. Diagnostic ratios of PAHs and the factor analysis identified the main sources of air pollution by this class of compounds over the southern Baikal region, which are combustion of coal, liquid fuel, and firewood, and also motor transport emissions.

Human exposure to polycyclic aromatic hydrocarbons in the atmosphere of an agricultural area of central Chile and inhalation cancer risk assessments

Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances prone to long-range atmospheric transport. Even in low concentrations, environmental exposure to PAHs can impact human health. In this study we aimed to i) investigate the occurrence of 15 polycyclic aromatic hydrocarbons (∑15PAHs), from August 2016 to January 2018, in the atmosphere of Molina, using polyurethane foam disks (PAS-PUF) in central Chile; and ii) perform deterministic and probabilistic (using Monte Carlo simulations) inhalation cancer risk assessments.Gas chromatography and tandem quadrupole mass spectrometry (GC- MS/MS) measured target PAHs. Results showed ∑15PAHs ranging from 2 ng m-3 to 108 ng m-3, with four-ring PAHs as the prevalent compounds, including phenanthrene (44%) and fluoranthene (24%). Winter season showed the highest PAH levels (increasing factor up to ∼8 times). PAHs diagnostic ratios showed the prevalence of pyrogenic combustion (winter) and petrogenic combustion (summer). Lifetime cancer risk assessments, using BaP-eq values, indicated an increased cancer risk for the exposed population considering different risk assessment approaches. Younger individuals were the most affected by an increased cancer risk at all sampling sites. The Monte Carlo probabilistic assessment indicated that infants and toddlers could be exposed to PAH air concentrations exceeding the cancer risk threshold in over 94% of the simulations. The coldest months in the studied region are critical for human exposure and health risk due to intense wood combustion. Indoor air can be even more relevant due to the chronic inhalation of the smoke and associated chemicals.

Molecular Composition, Seasonal Variation, and Size Distribution of n-Alkanes, PAHs, and Saccharides in a Medium-Sized City of Guanzhong Plain, Northwest China: Evaluation of Control Measures Executed in the Past Decade

Baoji is a medium-sized city in the Guanzhong Plain of northwest China. The compositions of three important organic groups, namely n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and saccharides in atmospheric aerosol with different aerodynamic diameters in power were determined. Both seasonal and daily trends of the target organic chemical groups were demonstrated. The concentration levels of total quantified n-alkanes and saccharides in total suspended particles (TSP) in winter were 541 ± 39 and 651 ± 74 ng·m-3, respectively, much higher than those of the other three seasons. A high total quantified PAHs concentration level of 59.6 ± 6.4 ng·m-3 was also seen in wintertime. n-Alkanes showed a bimodal percent distribution in spring, autumn, and winter. Two peaks were found with the particle sizes of 0.7 μm < Dp < 2.1 μm and 3.3 μm < Dp < 4.7 μm, respectively. In summer, a unimodal was seen with a peak of 4.7 μm < Dp < 5.8 μm. Dehydrated saccharides and PAHs present a unimodal size distribution peaking at the aerodynamic diameters of 0.7 µm < Dp < 2.1 µm. In contrast to glucose and fructose, they mainly exist in the coarse mode particles and have the highest concentrations at aerodynamic diameters of 4.7 µm < Dp < 9.0 µm. The geometric mean diameters (GMD) of n-alkanes and saccharides of the fine particles in winter were higher than in the other seasons. Compared with the data in 2008, the fossil fuel-derived n-alkanes and PAHs in winter decreased by nearly an order of magnitude in 2017. Both the carbon preference index (CPI) of n-alkanes and the diagnostic ratios of PAHs suggest that coal combustion and vehicle exhaust were the major pollution sources of the organic groups in the two decades. It should be noted that the contribution of traffic emissions greatly increased from 2008 to 2017, consistently with a large raise of registered vehicles in Baoji city. The overall results confirm that the control measures conducted by the local government in the recent decade mitigated the air pollution in this city.

Sources identification and distribution of aliphatic and aromatic hydrocarbons in coastal sediments of Arica Bay – Chile

ABSTRACT This study assesses the first approach regarding the origin, level of contamination, and spatial and vertical distribution of aliphatic and polycyclic aromatic hydrocarbons in coastal sediments of Arica’s Bay. Twenty-seven aliphatic hydrocarbons (AHs) and eighteen polycyclic aromatic hydrocarbons (PAHs) were studied at three depths in sediment cores collected from six locations in the coastal bay. The spatial distribution pattern of the molecular composition of aliphatic and aromatic hydrocarbons is consistent with the directions of the ocean currents from the northeast to the southwest. PAHs are mainly correlated with anthropogenic input sources to the bay. The total aliphatic hydrocarbons showed a wide concentration range from 112.07 to 2,382.43 ng·g−1 dry wt. while total PAHs ranged from 8.01 to 85.40 ng·g−1 dry wt. The vertical distribution of the total AHs shows a tendency to concentrate between 10–20 and 20–30 cm depth. Specific diagnostic characterisation ratios suggest that the bay sediments mainly consist of a mixture of autochthonous, predominantly marine sources composed of marine bacteria (n-C16, n-C18, and C20) and terrestrial plant derivatives (n-C29 and n-C31) and with a contribution of petrogenic hydrocarbons masked by biogenic hydrocarbons. The vertical distribution of the total polycyclic aromatic hydrocarbons is dominated by low molecular weight (LMW) PAHs of two and three rings, such as fluoranthene (FLT), phenanthrene (PHE), pyrene (PYR), and the highest concentrations are found between 10 and 20 cm depth of the sediment column. The PAH diagnostic ratios revealed a mixture of pyrogenic hydrocarbons (biomass and coal combustion) with petrogenic compounds from the Port of Arica and its neighbouring areas. According to the guidelines of UNEP for AHs and PAHs categorisation, the bay’s sediments may be classified from harmless to harmful due to AHs composition and low PAHs pollution.

Snow-Dependent Biogeochemical Cycling of Polycyclic Aromatic Hydrocarbons at Coastal Antarctica.

The temporal trend of polycyclic aromatic hydrocarbons (PAHs) in coastal waters with highly dynamic sources and sinks is largely unknown, especially for polar regions. Here, we show the concurrent measurements of 73 individual PAHs and environmental data, including the composition of the bacterial community, during three austral summers at coastal Livingston (2015 and 2018) and Deception (2017) islands (Antarctica). The Livingston 2015 campaign was characterized by a larger snow melting input of PAHs and nutrients. The assessment of PAH diagnostic ratios, such as parent to alkyl-PAHs or LMW to HMW PAHs, showed that there was a larger biodegradation during the Livingston 2015 campaign than in the Deception 2017 and Livingston 2018 campaigns. The biogeochemical cycling, including microbial degradation, was thus yearly dependent on snow-derived inputs of matter, including PAHs, consistent with the microbial community significantly different between the different campaigns. The bivariate correlations between bacterial taxa and PAH concentrations showed that a decrease in PAH concentrations was concurrent with the higher abundance of some bacterial taxa, specifically the order Pseudomonadales in the class Gammaproteobacteria, known facultative hydrocarbonoclastic bacteria previously reported in degradation studies of oil spills. The work shows the potential for elucidation of biogeochemical processes by intensive field-derived time series, even in the harsh and highly variable Antarctic environment.