Sources Of Polycyclic Aromatic Compounds Research Articles

It's time to reevaluate the list of priority polycyclic aromatic compounds: Evidence from a large urban shallow lake

Monitoring only 16 priority PAHs (Pri-PAHs) may greatly underestimate the pollutant load and toxicity of polycyclic aromatic compounds (PACs) in aquatic environments. There is an urgent need to reevaluate the list of priority PACs. To determine which PACs deserve priority monitoring, the occurrence, sources, and toxicity of 78 PACs, including 24 parent PAHs (Par-PAHs), 49 alkylated PAHs (Alk-PAHs), 3 oxygenated PAHs (OPAHs), carbazole, and dibenzothiophene were investigated for the first time in Lake Chaohu sediments, China. Concentrations of ∑Par-PAHs, ∑Alk-PAHs, and ∑OPAHs ranged from 35 to 165, 3.4–26, and 7.7–26 ng g−1, respectively. Concentrations of 16 Pri-PAHs have decreased by 1–2 orders of magnitude compared to a decade ago, owing to the effective implementation of PAHs emission control measures. Comparisons with the sediment quality guidelines indicated that 16 Pri-PAHs have negligible adverse effects on benthic organisms. Positive matrix factorization (PMF) model results showed that coal combustion was the major source of PACs (accounting for 23.5 %), followed by traffic emissions (23.4 %), petroleum volatilization (21.9 %), wood/biomass combustion (18.2 %), and biological/microbial transformation (13.1 %). The toxicity of PACs was assessed by calculating the BaP toxic equivalent concentrations (TEQBaP) and toxic units. It was found that Par-PAHs were the predominant toxic substances. In addition, monomethyl-BaPs, OPAHs, BeP, and 7,12-DMBaA should be prioritized for monitoring due to their noticeable contributions to overall toxicity. The contributions of different sources to the toxicity of PACs were determined based on PMF model results and TEQBaP values, which revealed that combustion sources mainly contributed to the comprehensive toxicity of PACs in Lake Chaohu sediments.

The missing information of aliphatic-like & aromatic-like Unresolved Complex Mixtures (UCMs) in background oceanic atmosphere: occurrence, identification and deposition

Oceanic air samples (gas + particle phases) were collected over the Shanghai-Arctic background oceanic region during the Chinese Arctic Research expedition 2021. Full scan mode (semi-quantitative) and selective ion monitoring mode (quantitative) were used to analyze separately 72 polycyclic aromatic compounds (PACs) & C11–C35 n-Alkanes (n-Alks) and unresolved complex mixtures (UCMs, including aromatic-like and aliphatic-like compounds) in these samples. The concentration of ΣPACs in the gas-phase and particle-phase were 0.40–8.5 ng m−3 (2.4 ± 1.7 ng m−3) and 0.059–1.1 ng m−3 (0.21 ± 0.23 ng m−3), respectively. While Σn-Alks in the gas-phase and particle-phase were 2.2–80 ng m−3 (mean = 18 ± 24 ng m−3) and 2.2–20 ng m−3 (mean = 8.6 ± 5.0 ng m−3), respectively. The semi-quantitative result indicated that aromatic-like UCMs were 14–1400 times higher than those of ΣPACs in these two phases, while aliphatic-like UCMs were 1.2–25 times higher than those of Σn-Alks. Through three-dimensional identification of the one-dimensional GC-MS chromatogram (with the x-axis representing GC retention time, the y-axis representing m/z, and the z-axis representing peak intensity), we found that aromatic-like UCMs were primarily composed of phenanthrene & anthracene similar PACs, while aliphatic-like UCMs were predominated by long-chain alkanes. The source identification shows that oil-gas leakage was the dominant source of PACs, followed by petroleum & coal combustion and biomass combustion; n-Alks might be mainly originated from anthropogenic sources, while nature sources at high latitudes cannot be ignored as well. Aromatic-like UCMs had a decreasing latitude trend and the presence of 5–6 ring aromatic-like UCMs enclosed within organic aerosols could pose a significant ecological risk, particularly in high latitude regions. Net uptake of atmospheric carbon caused by dry deposition of aromatic-like & aliphatic-like UCMs varied significantly geographically with mid- and low-latitude seas. The non-polar and weakly polar substances were not the major components of organic carbon in oceanic air of high latitude areas.

Emission characteristic, spatial distribution, and health risk of polycyclic aromatic compounds (PAHs, NPAHs, and OPAHs) from light-duty gasoline and diesel vehicles based on on-road measurements

Vehicle exhaust is the primary source of polycyclic aromatic compounds (PACs). Real road tests using a portable vehicle measurement system on light-duty gasoline vehicles and light-duty diesel trucks were conducted to investigate gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and oxy-PAHs (OPAHs) in vehicle exhaust with different emission standards, fuel types, and altitudes. The results showed that with the tightening of emission standards, the overall emission factors (EFs) of PACs decreased. Compared with China V diesel vehicles, the emissions of PAHs, OPAHs, and NPAHs from China VI diesel vehicles were 75.1 %, 84.4 %, and 61.2 % lower, respectively. With a ∼100 m increase in altitude, the EFs of PAHs, OPAHs, and NPAHs of diesel vehicles increased 1.88, 1.92, and 1.59 times due to incomplete combustion. In addition, the EFs of PAHs and OPAHs in gasoline vehicles were lower than those in diesel vehicles. In contrast, the proportion of PAHs with highly toxic components, such as dibenzo[a,h]anthracene (DahA) and benzo[a]pyrene (BaP), and the EFs of gas-phase NPAHs in gasoline vehicles were higher than those in diesel vehicles. Furthermore, the emissions of 1,8-DNP from diesel vehicles cannot be disregarded. 1,8-DNP was the main gas-phase NPAHs emitted by China VI and China V diesel vehicles, accounting for 49.3 % and 26.0 %, respectively. Moreover, gas-phase PACs contributed more to the EFs than particle-phase PACs, whereas particle-phase PACs have greater toxic effects. Although the EFs of PAHs are more than 100 times those of NPAHs, the toxic equivalent concentrations (TEQBaP) of PAHs in diesel and gasoline vehicles were approximately 6.5 times and 35 times those of NPAHs. The spatial distribution characteristics revealed that PACs emissions were mainly concentrated in urban areas and highways, and the differences in the toxicity of PACs emissions between different cities depended on the proportion of diesel vehicles. The average TEQBaP of PAHs and NPAHs in Haidong, Haibei, Huangnan, Hainan, Guoluo, and Yushu was 8.42 μg/m3 and 0.36 μg/m3, respectively, while those of Xining and Haixi were 0.24–0.29 μg/m3 and 0.09–0.108 μg/m3 higher, respectively. This study provides a comprehensive understanding of the emission characteristics, health risks, and spatial distribution of PACs from diesel and gasoline vehicle PACs in urban areas.

Migration patterns and health risk assessment of polycyclic aromatic compounds in typical coal fire source.

The Wuda coal fire in Inner Mongolia, China, is a global catastrophic event. It emits a huge volume of organic pollutants, including polycyclic aromatic compounds (PACs), which are widely concerning due to their physiological toxicity and environmental persistence. However, there is no systematic study on the enrichment and migration patterns of PACs emitted from coal fires. Here, we compared samples from coal fire sponges and surrounding soil, and analyzed 47 PACs using GC × GC-TOFMS. Data analysis showed that the average content of 16 polycyclic aromatic hydrocarbons (16PAHs) in the coal fire sponge was 15400.65ng/g, which is about 4.2 times higher than that in the surrounding soil. Meanwhile, 31 PACs were detected at levels far exceeding those of 16PAHs. The distribution pattern of PACs showed that coal fire sources are more likely to produce and store 16PAHs while surrounding soils are more likely to be enriched with PAH derivatives. The cancer risk assessment revealed a significant cancer risk in both the coal fires and the surrounding soil. The formation mechanism of oxygenated PAHs was also explored, and it was found that coal fires emit 16PAHs and alkylated PAHs, which oxidize to form oxygenated PAHs during migration to surrounding soils. The value of naphthaldehyde/alkylated naphthalene (< 2) can be referenced as characteristic markers of coal fire pollution. This provides a new perspective on the sources of PACs in the current environment.

A 150 years record of polycyclic aromatic compounds in the Sihailongwan Maar Lake, Northeast China: impacts of socio-economic developments and pollution control.

The geochemical composition of sediment cores can serve as a proxy for reconstructing past human and nature-driven environmental and climatic changes. We investigated the temporal variation in the concentrations and fluxes of polycyclic aromatic compounds (PACs) which include polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs, and azaarenes in the Sihailongwan Maar Lake and found that they remained low before 1950. The PAC concentrations and fluxes increased substantially since 1950, which was in good agreement with the fast socio-economic development, industrialization, and associated growth in fossil fuel consumption in China, particularly since the 1980s. After 2010, the PAC fluxes decreased, which was consistent with the implementation of air pollution control policies in China at that time. The concentration ratios of the sums of low to high molecular weight PAHs (LMW-PAHs/HMW-PAHs), benzo[e]pyrene/benzo[a]pyrene, and benzo[a]anthracene-7,12-dione/benzo[a]anthracene all decreased from bottom to top of the sediment core, reflecting the rapidly increasing contribution of emissions derived from high-temperature fossil fuel combustion (energy, transport and industry) to the PAC emissions in recent times at the expense of biomass burning. In addition, these data reflect the increasing local sources of PACs in more recent times because of the enhanced human activities in the area surrounding the Maar lake. Our results demonstrate that PAC fluxes and concentrations in sediment cores reflect the regional and national economic development and the efficiency of pollution control measures.

Assessment of asphaltene and resin fractions in crude oil using laser-induced fluorescence spectroscopy based on modified Beer-Lambert (LIFS-MBL)

Crude oil is one of the most significant petrogenic sources of polycyclic aromatic compounds (PACs). These substances play an essential role in the pollution of the marine environment. Therefore, the rapid identification of this pollutant source and its fractions is vital. For this purpose, a fast and on-site method of laser-induced fluorescence spectroscopy based on modified Beer-Lambert (LIFS-MBL) is proposed here using solvent densitometry. Three optical parameters of the self-quenching (K), the extinction (α), and the peak concentration (Cp) are experimentally extracted from MBL graphs. Note that the parameters above are known to be unique characteristics of various crude oils. The corresponding compounds are generally classified into saturate, aromatic, resin, and asphaltene fractions, abbreviated as SARA. Differentiation among these fractions is achieved using the LIFS-MBL method by selecting the optimal excitation wavelength at 405 nm. This line effectively rules out the light aromatic rings and focuses on heavy fractions. The correlation of optical parameters with heavy oil fractions is verified according to analysis of variance. Statistical relations are proposed to calculate crude oil fractions values. The values of light fractions including saturate and aromatic components can also be determined by the heavy fractions. In this method, the test time is notably reduced from four days using the standard methods to less than half an hour according to the presented LIFS-MBL technique.

Complex polycyclic aromatic compound mixtures in PM2.5 in a Chinese megacity: Spatio-temporal variations, toxicity, and source apportionment

Polycyclic aromatic compounds (PACs) are important toxic organic components in fine particulate matter (PM2.5), whereas the links between PM2.5 toxicity and associated PACs in ambient air are poorly understood. This study investigated the spatial–temporal variations of PACs in PM2.5 collected from 11 sampling sites across a Chinese megacity and characterized the reactive oxygen species (ROS) generation and cytotoxicity induced by organic extracts of PM2.5 based on cellular assays. The extra trees regression model based on machine learning and ridge regression were used to identify the key toxicants among complex PAC mixtures. The total concentrations of these PACs varied from 2.12 to 71.7 ng/m3 across the study city, and polycyclic aromatic hydrocarbons (PAHs) are the main PACs. The spatial variations of the toxicological indicators generally resembled those of the PAC concentrations, and the PM2.5 related to waste treatment facilities exhibited the strongest toxic potencies. The ROS generation was highly correlated with high molecular weight PAHs (MW302 PAHs), followed by PAHs with MW<302 amu and oxygenated PAHs, but not with nitrated PAHs and the plastics additives. The cell mortality showed weak correlations with these organic constituents. The associations between the biological endpoints and these PM2.5-bound contaminants were further confirmed by exposure to authentic chemicals. Four primary sources of PACs were identified, among which coal and biomass combustion sources (30.2% of the total PACs) and industrial sources (31.0%) were predominant. PACs emitted from industrial sources were highly associated with ROS generation in this city. Our findings highlight the potent ROS-generating potential of MW302 PAHs and the importance of industrial sources contributing to PM2.5 toxicity in this megacity, raising public concerns and further administration.

Polycyclic aromatic compounds (PACs) in tree barks and tree cores of a national large-scale coal-fired power base of China: Sources, atmospheric toxicities, and pollution histories

Polycyclic aromatic compounds (PACs) are important hazardous air pollutants in China due to the country's coal-dominant energy structure. In order to reveal the pollution characteristics, sources, toxicity, and pollution historical trends of PACs in the atmosphere of the middle reach of the Huaihe River (MRHR), a large-scale coal-fired power base of China, tree barks and tree cores were collected and employed as passive air samplers and historical trend recorders, and 76 PACs were identified for the first time. ΣPACs in tree barks ranged from 170 to 3800 ng g−1 (mean = 700 ± 720 ng g−1), with the high concentrations observed mainly in the coal-mining and coal-bearing area. 16 priority PAHs (PriPAHs) were the predominant substances and accounted for 59 ± 8.3 % of ΣPACs. The combustion of coal and fuel oil was the most significant source of PACs, accounting for 43 % of ΣPACs, followed by the combustion of biomass (30 %) and non-combustion sources (27 %). Based on a bark-air partitioning model, volumetric air concentrations for ΣPACs were calculated to be 450–11,000 ng m−3 (mean = 1600 ± 2000 ng m−3). The BaP-toxic equivalent concentrations (TEQBaP) of ΣPACs (mean = 9.7 ± 15 ng m−3) were significantly higher than the Chinese guideline (1 ng m−3) and were mostly caused by coal & fuel oil combustion (55 ± 13 %). High molecular weight PACs were detected in lower percentages in tree cores than in tree barks, indicating that PACs in the particle phase were difficult to enter the tree core. Major PACs decreased in tree core samples between 2000 and 2020 as pollution control efforts improved, however, some PACs showed different trends when influenced by point sources.

Simultaneous Determination of 79 Polar and Non-Polar Polycyclic Aromatic Compounds in Airborne Particulate Matter by Gas Chromatography – Tandem Mass Spectrometry

Research on Polycyclic Aromatic Compounds (PACs) in the atmospheric environment has been mainly focused on the 16 EPA’s PAHs. Due to toxicological relevance and particular emission sources, there is a research need in broadening the scope of PACs analysis to include polar and semi-polar PACs in new analytical methods. Here, we describe a single GC-MS/MS method to simultaneously determine 79 polar, semi-polar and non-polar PACs. Temperature gradient and injection conditions were optimized. Optimal Multiple Reaction Monitoring (MRM) and pseudo-MRM mass transitions were searched to enhance the detection. PACs were extracted from particulate samples by Pressurized Liquid Extraction (PLE). The choice of the optimal extraction solvent was carefully evaluated. Instrumental LOQ were from 1 to 2 ng. The method was validated against linearity of the calibration, intra-day and inter-day variability, LOQ and recoveries. The analysis of a Diesel Particulate Matter Certified Reference Material enabled a firm method validation. The method was applied to PM10 samples from a residential parking lot. PACs total amount varied from 2.3 to 14 ng/m3. The most abundant PACs were phthalic anhydride, 1,8-naphthalic anhydride and benzo(b)fluoranthene. PAHs diagnostic ratios enabled the identification of fuel combustion and vehicular traffic as the main source of PACs.

Alkylated Polycyclic Aromatic Hydrocarbons Are the Largest Contributor to Polycyclic Aromatic Compound Concentrations in the Topsoil of Huaibei Coalfield, China.

Alkyl polycyclic aromatic hydrocarbons (APAHs) are more toxic and persistent than their parent compounds. Here, the concentrations, composition profiles, and spatial distribution of polycyclic aromatic compounds (PACs) in 127 topsoil samples from Huaibei coalfield were analyzed. The PAC concentrations in different functional areas were significantly different: mining area > industrial area > residential area > agricultural area. APAHs were the major contributors to PACs, accounting for 71–83% of total PACs. Alkylnaphthalenes and alkylphenanthrenes were the primary APAH components, accounting for 83–87% of APAHs. Principal component analysis showed that petrogenic source, coal and biomass combustion, and vehicle emissions were the primary sources of PACs. By comparing the fingerprint information of soil, coal, and coal gangue, it was hypothesized that the petrogenic source of PAC pollution in typical mining areas and surrounding areas are coal particle scattering and coal gangue weathering. Some coal mining and industrial areas potentially pose risks to children, whereas others do not. There are limited evaluation criteria for alkyl PAHs; hence, the estimated risk is likely lower than the actual risk. In addition to the conventional 16 PAHs, it is critical to consider a broader range of PACs, especially APAHs.

Alkylated Polycyclic Aromatic Compounds in Road Runoff Are an Environmental Risk and Should Be Included in Future Investigations.

Polycyclic aromatic compounds (PACs) and metals are important contaminants in road runoff. Vital mitigation measures against aquatic contamination from road runoff include the use of sedimentation ponds. However, it has been demonstrated that ecosystems in sedimentation ponds might be affected by road runoff. Sediments from six natural ponds and 27 sedimentation ponds were investigated to determine the environmental risk of contaminants. The amount of traffic on the respective roads associated with the sedimentation ponds was correlated with the environmental concentrations. Quantification included seven metals, the 16 US Environmental Protection Agency polycyclic aromatic hydrocarbons, alkylated PACs, dibenzothiophene, benzo[e]pyrene, and perylene. The environmental risk was assessed according to the European Union Water Framework Directive guidelines. Sedimentation ponds had a higher level of contaminants than natural ponds, and environmental risks were dominated by the concentration of PACs. Alkylated PACs contributed to the environmental risk posed by PACs and should be included in future monitoring. Only Cu and Zn were measured at concentrations above the environmental quality standards (EQSs), while 13 PACs exceeded the EQS. Sediment concentrations of Cu, Zn, and most PACs correlated significantly with the amount of traffic. The sources of PACs were determined by source apportionment ratios between PACs. Alkylation and pyrogenic indices showed that sources in natural ponds were of mostly pyrogenic origin, whereas in sedimentation ponds they were predominantly petrogenic. Asphalt was the probable main source of PACs. A hierarchical clustering technique was used to investigate both the environmental risks and the pattern of PACs in the ponds and revealed that a few sedimentation ponds were not protecting the environment as intended because the upper sediment layers had not been regularly dredged. Environ Toxicol Chem 2022;41:1838–1850. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Tracking historical sources of polycyclic aromatic compounds (PACs) in dated lake sediment cores near in-situ bitumen operations of Cold Lake, Alberta

Most bitumen in the Alberta oil sands (Canada) is extracted by thermal in-situ recovery. Despite the widespread use of in-situ bitumen extraction, little information is available on the release of petroleum hydrocarbons by this method to adjacent land and water. Here we analyzed the composition and abundance of parent and alkylated polycyclic aromatic compounds (PACs) in 11 radiometrically-dated lake sediment cores collected near in-situ operations at Cold Lake Alberta to assess potential petroleum contamination sources to surrounding lakes over the past century. Like open-pit mining areas, alkylated PACs in Cold Lake sediments were elevated compared to unsubstituted parent PACs and increased coeval with the onset of bitumen extraction in the area. Diagnostic ratios and pyrogenic indices showed that PAC sources to these lake sediments were dominantly pyrogenic, likely from historic forest fires, however they shifted to more petrogenic sources coeval with expanding oil sands extraction at Cold Lake. PACs in sediment from regional lakes are weakly correlated to their proximity to in-situ oil wells, once corrected for lake area. These results suggest that in-situ operations, via diesel-fueled vehicular emissions and the combustion of natural gas for steam generation, are a source of PACs to nearby lakes, but PACs did not exceed Canadian sediment quality guidelines for the protection of aquatic life.

Polycyclic aromatic compounds in the Canadian Environment: Aquatic and terrestrial environments

Polycyclic aromatic compounds (PACs) are ubiquitous across environmental media in Canada, including surface water, soil, sediment and snowpack. Information is presented according to pan-Canadian sources, and key geographical areas including the Great Lakes, the Alberta Oil Sands Region (AOSR) and the Canadian Arctic. Significant PAC releases result from exploitation of fossil fuels containing naturally-derived PACs, with anthropogenic sources related to production, upgrading and transport which also release alkylated PACs. Continued expansion of the oil and gas industry indicates contamination by PACs may increase. Monitoring networks should be expanded, and include petrogenic PACs in their analytical schema, particularly near fuel transportation routes. National-scale roll-ups of emission budgets may not expose important details for localized areas, and on local scales emissions can be substantial without significantly contributing to total Canadian emissions. Burning organic matter produces mainly parent or pyrogenic PACs, with forest fires and coal combustion to produce iron and steel being major sources of pyrogenic PACs in Canada. Another major source is the use of carbon electrodes at aluminum smelters in British Columbia and Quebec. Temporal trends in PAC levels across the Great Lakes basin have remained relatively consistent over the past four decades. Management actions to reduce PAC loadings have been countered by increased urbanization, vehicular emissions and areas of impervious surfaces. Major cities within the Great Lakes watershed act as diffuse sources of PACs, and result in coronas of contamination emanating from urban centres, highlighting the need for non-point source controls to reduce loadings.

Tracking Historical Sources of Polycyclic Aromatic Compounds (PACs) in Dated Lake Sediment Cores Near In-Situ Bitumen Operations of Cold Lake, Alberta

Tracking Historical Sources of Polycyclic Aromatic Compounds (PACs) in Dated Lake Sediment Cores Near In-Situ Bitumen Operations of Cold Lake, Alberta

Polycyclic aromatic compounds in particulate matter and indoor dust at preschools in Stockholm, Sweden: Occurrence, sources and genotoxic potential in vitro

Children spend a significant amount of their day in preschool; thus, environmental quality at preschools may have an impact on children's health. In the present study, we analyzed polycyclic aromatic compounds (PACs), including PAHs, alkylated PAHs and oxygenated PAHs (OPAHs), in indoor and outdoor air particulate matter (PM10) and indoor dust at preschools in Stockholm, Sweden. There were significant correlations between PAC levels in outdoor and indoor PM10, with in general higher PAC levels outdoors. Fluoranthene and pyrene were detected at highest levels in all sample types, although phenanthrene and methylated phenanthrene derivatives also were found at high levels in indoor dust. In addition, the highly carcinogenic PAHs 7H-benzo[c]fluorene, 7,12-dimethylbenz[a]anthracene, benz[j]aceanthrylene, and dibenzo[a,l]pyrene were detected in some samples. Benzanthrone was the most prevalent OPAH in PM10 samples and 9,10-anthraquinone in indoor dust. Based on diagnostic ratios and Positive Matrix Factorization we identified vehicle emission and biomass burning as important PAC sources for all samples analyzed. However, poor correlation between PAC levels in indoor PM10 and indoor dust suggested additional sources for the latter. Measuring activation of DNA damage signaling in human cells exposed to organic extracts of the samples indicated substantial genotoxic potential of outdoor PM10 and indoor dust. Determination of benzo[a]pyrene equivalents demonstrated that the highly potent PAHs benz[j]aceanthrylene and dibenz[a,h]anthracene contributed more than 20% to the total carcinogenic potency of the samples. We conclude that PAC levels at Stockholm preschools are relatively low but that outdoor air quality may impact on the indoor environment.

Polycyclic aromatic compounds in ambient air in the surface minable area of Athabasca oil sands in Alberta (Canada)

This study characterizes concentrations and describes the spatiotemporal patterns of ambient air polycyclic aromatic compounds (PACs) between 2011 and 2015 in the Athabasca oil sands region (AOSR). 24-hour integrated ambient air samples were collected at multiple sites and analyzed for 110 PACs. Alkylated polycyclic aromatic hydrocarbons (alk-PAHs) formed the majority of the PACs in air and correlated with unsubstituted PAHs, suggesting common emission source(s) and/or origin. Concentrations of individual PACs varied spatially and seasonally. Temporal variability of PAC concentrations was evident, however based on Seasonal Mann-Kendall test a monotonic increase in concentrations at the monitored sites was not significant at p < 0.05. PAC concentrations measured during wildfire events (which were excluded from the trend analysis above) were the highest and were enriched in higher molecular weight alk-PAHs. This enrichment in alk-PAHs has not been previously reported and is believed to be a unique phenomenon for the Athabasca region. Sulfur and petroleum coke stockpiles, mining and bitumen processing were identified as potential sources of PACs near the main production operations, while mining and diluent naphtha production stood out as possible sources at a site 16 km north of the main open-pit mining area.

Forage fish and polycyclic aromatic compounds in the Fort McMurray oil sands area: Body burden comparisons with environmental distributions and consumption guidelines

The Fort McMurray region in northeastern Alberta (Canada) is rich in natural sources of polycyclic aromatic compounds (PACs) from exposed bitumen beds; anthropogenic sources are being released with increased oil sands industry expansion. Here we report on investigations of PACs (47 compounds) in three species of forage fish collected during the 2012–2013 Joint Oil Sands Monitoring Program (JOSMP) fish health investigations and compare results with PAC data for sediment and water collected under JOSMP and earlier programs. PAC concentrations in sediments varied three orders in magnitude and were highest at downstream tributary mouths, which flowed through the exposed McMurray Formation, and along reaches of the Athabasca River where the formation was exposed. PAC concentrations in water were less variable but with higher concentrations near exposed bitumen beds. Forage fish exhibited the weakest spatial gradients in ΣPACs concentration, which averaged 102 ± 32 ng/g in trout-perch from the Athabasca River, 125 ± 22 ng/g in lake chub from the Ells River, and 278 ± 267 ng/g in slimy sculpin from the Steepbank, Firebag, and Dunkirk Rivers. Low-molecular weight compounds, particularly naphthalenes and fluorenes, dominated fish PACs. Phenanthrenes occurred in greater percent composition in fish caught in areas where PAC concentrations in sediments were higher due to the proximity of bitumen sources than in other areas. Dibenzothiophene, a major component of bitumen PAC, was a minor component of fish ΣPACs. Forage fish PAC concentrations were below fish consumption guidelines established by the European Commission (2011) and for the reopening of the commercial fisheries closed by the Deepwater Horizon oil spill. PAC concentrations in forage fish were similar to concentrations observed in many other studies (fish market surveys, estuaries, and marine waters) and lower than in fish sampled from highly impacted areas (near refineries, harbors, and other industrialized areas).

Polycyclic aromatic compounds in urban air and associated inhalation cancer risks: A case study targeting distinct source sectors

Passive air sampling was conducted in Toronto and the Greater Toronto Area from 2016 to 2017 for 6 periods, in order to investigate ambient levels of polycyclic aromatic compounds (PACs) associated with different source types. The selected sampling sites (n = 8) cover geographical areas with varying source emissions including background, traffic, urban, industrial and residential sites. Passive air samples were analyzed for PACs which include PAHs, alkylated PAHs (alk-PAHs), dibenzothiophene and alkylated dibenzothiophenes (DBTs) and results for PAHs were used to calculate inhalation cancer risks using different approaches. The samples were also characterized for PAH derivatives including nitrated PAHs (NPAHs) and oxygenated PAHs (OPAHs). Concentrations of Σalk-PAHs and DBTs, which are known to be enriched in fossil fuels, as well as ΣNPAHs, were highest at a traffic site (MECP) located adjacent to the 18-lane Highway 401 that runs across Toronto. Except for an industrial site (HH/BU), PAC compositions were similar across the sampling sites with Σalk-PAHs being the most abundant class of PACs suggesting traffic emission was a major contributor to PACs in the atmosphere of Toronto. The industrial site exhibited a distinct chemical composition with ΣPAHs dominating over Σalk-PAHs and with elevated levels of fluoranthene, 9-nitroanthracene, and 9,10-anthraquinone, which likely reflects emissions from nearby industrial sources. MECP and HH/BU exhibited higher lifetime excess inhalation cancer risks indicating an association with traffic and industrial sources. The importance of the traffic sector as a source of PACs to ambient air is further supported by strong correlations of the ΣPAHs, Σalk-PAHs, DBTs, and ΣOPAHs with NOx. This study highlights the importance of traffic as an emission source of PACs to urban air and the relevance of PAC classes other than just unsubstituted PAHs that are important but currently not included in air quality guidelines or for assessing inhalation cancer risks.

Characterization of Polycyclic Aromatic Compounds in Commercial Pavement Sealcoat Products for Enhanced Source Apportionment.

Coal tar-based sealcoat (CTSC) products are an urban source of polycyclic aromatic compounds (PACs) to the environment. However, efforts to assess the environmental fate and impacts of CTSC-derived PACs are hindered by the ubiquity of (routinely monitored) PACs released from other environmental sources. To advance source identification of CTSC-derived PACs, we use comprehensive two-dimensional gas chromatography-high resolution mass spectrometry (GC × GC/HRMS) to characterize the major and minor components of CTSC products in comparison to those in other sources of PACs, viz., asphalt-based sealcoat products, diesel particulate, diesel fuel, used motor oil and roofing shingles. GC × GC/HRMS analyses of CTSC products led to the confident assignment of compounds with 88 unique elemental compositions, which includes a set of 240 individual PACs. Visualization of the resulting profiles using Kendrick mass defect plots and hierarchical cluster analysis highlighted compositional differences between the sources. Profiles of alkylated PAHs, and heteroatomic (N, O, S) PACs enabled greater specificity in source differentiation. Isomers of specific polycyclic aromatic nitrogen heterocycles (PANHs) were diagnostic for coal tar-derived PAC sources. The compounds identified and methods used for this identification are anticipated to aid in future efforts on risk assessment and source apportionment of PACs in environmental matrices.

Comprehensive two-dimensional gas chromatography high-resolution mass spectrometry for the analysis of substituted and unsubstituted polycyclic aromatic compounds in environmental samples

Polycyclic aromatic compounds (PACs) consists of multiple compounds and the number of theoretically possible isomers can reach into the thousands. Currently each PAC group is quantified collectively as a single group of compounds. However, individual PACs can reveal important information on how the PACs were formed and this information may be used to determine sources of PACs in environmental samples, It is hypothesized that many of the limitations with characterizing alkylated PACs with one dimensional gas-chromatography (1D GC) can be circumvented using GC × GC (two dimensional gas chromatography). Here we apply comprehensive GCxGC coupled to high-resolution time of flight mass spectrometry (GC × GC-HFTOF-MS) to aid in the separation, identification and quantitation of APACs in three environmental matrices: mussel tissue (Mytilus edulis), lubricating oil and coal. In the absence of authentic analytical standards, differences in the mass spectral fragmentation pattern of isomers were used to confirm the identity of isomers within a PAC group. The method was validated according to the EURACHEM guidelines and used to quantify a biological standard reference material (SRM 2974a). The method met all the standard method performance requirements such as trueness, precision and measurement of uncertainty and is fit for quantifying these compounds in biota. Furthermore, the method was used to identify and quantify additional PAC compounds in the SRM 2974a material which to date have not been certified. With appropriate statistical analytical tools, the described GC × GC method can be used as a tool for more robust source fingerprinting and source apportionment of PACs in the environment.