We examined polycyclic aromatic compounds (PACs) and petroleum biomarkers (steranes, hopanes, and terpanes) in radiometrically-dated lake sediment cores from the Athabasca oil sands region (AOSR) and the Peace-Athabasca Delta (PAD) region in Alberta (Canada) to determine whether contributions from petroleum hydrocarbons have changed over time. Two floodplain lakes in the PAD (PAD 30, PAD 31) recorded increased flux of alkylated PACs and increased petrogenic (petroleum-derived) hydrocarbons after ∼1980, coincident with a decline of sediment organic carbon content and a rise of bulk sedimentation rate, likely due to increased Athabasca River flow. A large expansion of upstream oilsands mining, upgrading, and refining may also have contributed to the observed shift to more petrogenic hydrocarbons to sediments since the 1980s. Alkylated PAC flux increased in the floodplain lake analyzed within the AOSR (Saline Lake) since the 1970s–1980s, coincident with a sharp rise in sediment organic carbon content and increased contributions of petrogenic hydrocarbons. These changes identify increased supply of petrogenic PACs occurred as Athabasca River floodwaters waned, and may implicate aerial contributions of petrogenic hydrocarbons from oilsands activity. PACs and petroleum biomarkers (steranes, hopanes, and terpanes) in sediment cores from Saline Lake, PAD 30 and PAD 31 revealed a predominance of petrogenic hydrocarbons in these lakes. In contrast, we recorded minimal petrogenic hydrocarbons in the reference lakes outside the surface minable area of the AOSR and PAD (Mariana Lake and BM11), though we noted slight increases in petrogenic contributions to modern (2010–2016) sediments. We show how a combined analysis of PACs and petroleum biomarkers in sediments is useful to quantify petrogenic contributions to lakes with added confidence and highlight the potential for petroleum biomarkers in lake sediment cores as a novel and effective method to track petroleum hydrocarbons in lake sediment.

Alberta’s oil sands tailings ponds are suspected to be a source of fugitive emissions of polycyclic aromatic compounds (PACs) to the atmosphere. Here we report, for the first time, fluxes of 6 parent and 21 alkylated PACs based on the measured co-located air and water concentrations using a two-film fugacity-based model (FUG), an inverse dispersion model (DISP) and a simple box model (BOX). Air samples were collected at the Suncor Tailings Pond 2/3 using a high volume air sampler from the “pond” and towards the pond (“non-pond”) directions separately. Mean ∑₂₇PACs in air from the “pond” direction was greater than the “non-pond” direction by a factor of 17. Water-air fugacity ratio of 20 PACs quantifiable in water indicated net volatilization from water. Dispersion and box model results also indicated upward fluxes of 22 PACs. Correlation between the estimated flux results of BOX and DISP model was statistically significant (r = 0.99 and p < 0.05), and correlation between FUG and DISP results ranged from 0.54 to 0.85. In this first-ever assessment of PAC fluxes from tailings pond, the three models confirmed volatilization fluxes of PACs indicating Suncor Tailings Pond 2/3 is a source of PAC emissions to the atmosphere. This study addressed a key data gap identified in the Joint Oil Sands Monitoring Emissions Inventory Compilation Report (Government of Alberta and Canada, 2016) which is the lack of consistent real-world tailings pond fugitive emission monitoring of organic chemicals. Our findings highlight the need for measurements from other tailings ponds to determine their overall contribution in releasing PACs to the atmosphere. This paper presents a practical method for estimating PAC emissions from other tailings ponds, which can provide a better understanding of these fugitive emissions, and thereby help to improve the overall characterization of emissions in the oil sands region.

An experimentally induced three-dimensional petroleum seepage flume was used to investigate its migration in heterogeneous soil layers and a method for monitoring resistivity was adopted, under conditions of fluctuating water levels and rainfall. The corresponding mechanisms were then analyzed based on the resistivity characteristics and combined with three-dimensional inversion images. Finally, physical and chemical property analysis was conducted to verify the results of resistivity monitoring. The results demonstrated that: (1) In the process of natural oil leakage, the variation of soil resistivity presents a concave shape in the resistivity profile. Thus, oil migration exhibited the following patterns. At first, circular migration front was dominant in a vertical direction. Subsequently, after vertical migration was impeded, lateral migration was dominant. As the crude oil gradually accumulated, the migration front broke through the limitation of lithologic interface and continued vertically. (2) By comparing the two resistivity monitoring methods, namely the Wenner and Pole-pole methods, it was demonstrated that the inversion resistivity measured by Wenner method was closer to the true resistivity, and the resistivity variations were more distinguishable. (3) The resistivity inversion profile demonstrated that the low resistivity anomaly of the crude oil leakage area was related to the low water content of the soil layer in the test area. (4) Fluctuations in water level increased the diffusion range of crude oil beyond the original pollution source area, especially horizontally. (5) Percolation of rainfall caused the water level to rise, and the crude oil was evenly distributed in the soil layers above the capillary zone. (6) Through sample analysis and verification, it was demonstrated that the resistivity method can accurately and intuitively present the characteristics of crude oil migration. These results provide theoretical support for the rapid determination of the migration range and characteristics of crude oil in heterogeneous soil layers.

This research determines the intertemporal relationships caused by the coal, oil, and natural gas consumption in the carbon dioxide emission by the G7 countries from 1965 to 2018. Auto-regressive and Distributed Lags models and Bound test were used to detect cointegration and understand the dynamic effect. Due to structural breaks occurred in the variables, two dummy variables for the periods of breaks, 1978 and 1990 were incorporated respectively. Positive causality was identified, in the sense that the consumption of fossil fuels provides an increase in carbon dioxide emissions. Short-term elasticities indicate that an increase of 1 percentage point in the consumption of oil, coal, and natural gas will cause, respectively, an increase of 0.4823%, 0.3140%, and 0.1717% in carbon dioxide emissions. In the long run, the increase of 1 percentage point in the consumption of oil, coal, and natural gas will cause, respectively, an increase of 0.4924%, 0.2692%, and 0.1829% in carbon dioxide emissions. The error correction model (ECM = −0.4739) indicates that 47.39% of a shock in the carbon dioxide emissions variable is resolved in one year and after 2 years, carbon dioxide emissions return to long term equilibrium.

Oil spills can result in changes in chemical concentrations along coastlines. In prior work, these concentration changes were used to evaluate the date sediment was impacted by oil (i.e., oil exposure date). The objective of the current study was to build upon prior work by using the oil exposure date to compute oil spill chemical (OSC) concentrations in shoreline sediments before and after exposure. The new method was applied to OSC concentration measures collected during the Deepwater Horizon oil spill with an emphasis on evaluating before and after concentrations in muddy versus sandy regions. The procedure defined a grid that overlaid coastal areas with chemical concentration measurement locations. These grids were then aggregated into clusters to allow the assignment of chemical concentration measurements to a uniform coastal type. Performance of the method was illustrated for ten chemicals individually by cluster, and collectively for all chemicals and all clusters. Results show statistically significant differences between chemical concentrations before and after the calculated oil exposure dates (p < 0.04 for each of the 10 chemicals within the identified clusters). When aggregating all chemical measures collectively across all clusters, chemical concentrations were lower before oil exposure in comparison to after (p < 0.0001). Sandy coastlines exhibited lower chemical concentrations relative to muddy coastlines (p < 0.0001). Overall, the method developed is a useful first step for establishing baseline chemical concentrations and for assessing the impacts of disasters on sediment quality within different coastline types. Results may be also useful for assessing added ecological and human health risks associated with oil spills.

Direct utilization of waste polyethylene terephthalate (PET) from the environment to form highly porous aerogel technology for oil absorption is an attractive approach from the view point of green chemistry. However, the oil absorption reaction is limited by low oil absorption capacity and less stability. For now, silica aerogel are used to solve these problem. Our goal is to substitute to these silica aerogel with PET aerogel technology. Herein, we have prepared an environmental waste PET based aerogel with 1.0:0.5 wt% PET, polyvinyl alcohol (PVA), and glutaraldehyde (GA) 0.2% v/v were dispersed in 10 mL DI water, followed by homogenization (30 min), sonication (10 min), and ageing (2 h) at 70 °C. To escape macroscopic cracking, cooling (8 h) at 4 °C was followed by freezing (6 h), freeze drying at −80 °C, and 5 mTorr for 18 h. The hybrid PET aerogel displays excellent performance towards oil absorption. Notably it showed high absorption capacity towards the different oils about 21–40 times its own weight, depending on the viscosity and density of the oil and solvents within 15–35 s, 25 °C, and 2 × 2 cm aerogel size. In addition, the aerogel shows there is no change in structure after several recycles due to high mechanical strength. Furthermore, because of the PET aerogel's high porosity (99.74%) and low density (0.0311 g/cm³), close bonding between PET-PVA occurs. Therefore, aerogel shows hydrophobic nature, good mechanical strength, high thermal stability, arrangement of the interconnected fibrillar pore network offers a high surface to volume ratio, low surface energy, high surface roughness, and more reusability. All these parameters are responsible for high oil absorption.

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.

The Amazon coastal zone has become contaminated with organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs). However, information about their distribution and sources in this area is scarce, despite increasing deforestation and oil exploitation. Therefore, individual PAHs were analysed in the sediments of the Oyapock estuary, which is located in the Amazon coastal zone. This study provides information about the spatial and short-term temporal distributions of PAHs and discusses the major sources of PAHs to better understand the anthropogenic processes occurring in adjacent areas. The concentrations of all sixteen priority PAHs defined by the US EPA (United States Environmental Protection Agency, ∑₁₆PAHs) ranged from 10.9 to 138.8 ng g⁻¹ with a mean and standard deviation = 37.9 ± 20.5 and indicated that this estuary is not contaminated, while the mean levels were similar to those found in other Amazon regions and pristine areas along the coast of Brazil. No significant differences were found in the sedimentary PAHs levels between the wet and dry sampling campaigns, despite the different climatic conditions. Diagnostic ratios, positive matrix factorization (PMF) and cluster analysis have shown that the majority of the investigated PAHs were derived from combustion processes (at least 55.1%, as estimated by the PMF model). Localized source inputs from oil and its by-products concomitantly with natural/biogenic sources appear to be secondary sources. The PAH contribution from biomass and wood combustion was approximately 13.6% and was relatively lower than other regions of the Amazon that are undergoing massive biomass burning. As the first study of PAHs in this region, this study provides vital information on the healthy state of the estuary and can serve as a baseline for assessing the impacts of acute oil disasters or the chronic input of PAHs as a result of human settlements.

The response of freshwater invertebrates following accidental releases of oil is not well understood. This knowledge gap is more substantial for unconventional oils such as diluted bitumen (dilbit). We evaluated the effects of dilbit on insect emergence and benthic invertebrates by conducting experimental spills in limnocorrals (10-m diameter; ~100-m³) deployed in a boreal lake at the IISD-Experimental Lakes Area, Canada. The study included seven dilbit treatments (spill volumes ranged from 1.5 L [1:66,000, oil:water, v/v] to 180 L [1:590, oil:water, v/v]), two controls, and additional lake reference sites, monitored for 11 weeks. Invertebrate emergence declined at the community level following oil addition in a significantly volume-dependent manner, and by 93–100 % over the 11 weeks following the spill in the highest treatment. Dilbit altered community structure of benthic invertebrates, but not abundance. One-year post-spill and following oil removal using traditional skimming and absorption techniques, benthic richness and abundance were greater among all treatments than the previous year. These results indicate that recovery in community composition is possible following oil removal from a lake ecosystem. Research is needed concerning the mechanisms by which surface oil directly affect adult invertebrates, whether through limiting oviposition, limiting emergence, or both. The response of benthic communities to sediment tar mats is also warranted.

The valorization of municipal solid waste incineration bottom and fly ashes (IBA and IFA) as catalysts for thermochemical plastic treatment was investigated. As-received, calcined, and Ni-loaded ashes prepared via hydrothermal synthesis were used as low-cost waste-derived catalysts for in-line upgrading of volatile products from plastic pyrolysis. It was found that both IBA and air pollution control IFA (APC) promote selective production of BTEX compounds (i.e., benzene, toluene, ethylbenzene, and xylenes) without significantly affecting the formation of other gaseous and liquid species. There was insignificant change in the product distribution when electrostatic precipitator IFA (ESP) was used, probably due to the lack of active catalytic species. Calcined APC (C-APC) demonstrated further improvement in the BTEX yield that suggested the potential to enhance the catalytic properties of ashes through pre-treatment. By comparing with the leaching limit values stated in the European Council Decision, 2003/33/EC for the acceptance of hazardous waste at landfills, all the ashes applied remained in the same category after the calcination and pyrolysis processes, except the leaching of Cl⁻ from the ESP, which was around the borderline. Therefore, the use of ashes in catalytic reforming application do not significantly deteriorate their metal leaching behavior. Considering its superior catalytic activity towards BTEX formation, C-APC was loaded with Ni at 15 and 30 wt%. The Ni-loading favored an increase in overall oil yield, while reducing the gas yield when compared to the benchmark Ni loaded ZSM catalyst. However, Ni addition also caused the formation of more heavier hydrocarbons (C20–C35) that would require post-treatment to recover favorable products like BTEX.