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Two diluted bitumen, Cold Lake Blend (CLB), Accessed Western Blend (AWB), and Alberta Sweet Mixed Blend #5 crude oil (ASMB#5), were spiked into 3.3% NaCl aqueous solution, then exposed to natural sunlight for 90 days in the winter and summer in the Northern Hemisphere (Ottawa, Canada). The effects of temperature and solar intensity on the photolytic behavior of diluted bitumen were evaluated. Simultaneously, the photolytic similarities and differences between diluted bitumen and crude oil were compared. It was found that, in all test oils, the decrease of all total petroleum hydrocarbons followed a pseudo-first-order reaction kinetic with the exposure time regardless of seasons. Aromatic fractions had the highest apparent rate constants. Similarly, the chemical fingerprinting analysis of test oils demonstrated that polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues (APAHs) were the most photosensitive compounds among the identified targets, followed by n-alkanes, then terpanes, and steranes. The photolytic efficiencies of the target petroleum hydrocarbons in ASMB#5 were generally higher than the two diluted bitumen. Photolysis of APAHs occurred faster in summer than in winter; however, APAHs with different number of rings and degree of alkylation did not have obvious photolytic differences. These phenomena suggest that the photolytic similarities between dilbits and conventional crude oil depend on their similar chemical structure of petroleum hydrocarbons; their differences depend on the specific oil properties. The accumulated solar irradiation intensity and temperature are the main factors contributing to their photolytic differences for winter and summer exposed oils.

The characterization, occurrence, fate and behaviour of spilled oil in the affected boreal freshwater ecosystem were investigated in this study following a spill in March 2015, in Gogama, Ontario, Canada. A physicochemical property analysis of the source oil showed that the spilled oil was consistent with a conventional light oil. Oil samples collected immediately following the spill had lost their relatively light molecular alkanes and polycyclic aromatic hydrocarbons (PAHs) due to evaporation or dissolution. Twenty months post-spill, oil contamination levels decreased at sites located furthest from the accident site. Most of the sampling sites close to the incident site contained lightly weathered source oil, while some sediment contained heavily weathered source oil. Biogenic and pyrogenic inputs were also present in all the oil-contaminated sediments, where light molecular weight hydrocarbons had higher loss rates than heavy ones. Branched alkanes were more resistant to loss than corresponding straight isomers. Water samples usually had a lower loss of both alkylated PAHs and alkanes than in the underlying sediments. This difference can be ascribed to the fractionation of petroleum hydrocarbons between being deposited in sediment, and being released into water phases, especially when oils were freshly released into the water phase by disturbing bottom sediment. Aside from the rapid loss through evaporation and dissolution, microbial degradation was the major weathering process causing the loss of hydrocarbons 20 months after the spill.

Lubricating oil plays a critical role to reduce friction and to ensure the machines are more energy efficient in terms of fuel consumption and power output. The use of unqualified lube oil can result in malfunctions and damage to engines and machinery. Since petroleum-based lube oils are among the most valuable refined products, in some regions, fake, used, or waste lube oils have occasionally been deliberately adulterated into lube oil to extend the volume sold. On the other hand, used or waste lube oil is hazardous material, containing contaminants such as metals and polycyclic aromatic hydrocarbons produced by the engine during use. It becomes an environmental problem when it is purposely disposed of or accidentally spilled into the environment. Some jurisdictions now have relevant regulations to prohibit these illegal activities; therefore, forensic analysis of lube oils is essential to differentiate fake and used lube products from virgin oils, to identify and to track the adulteration source, and to identify the source of spilled oil. This work involved a fingerprinting analysis of a suite of oil samples including a virgin lube oil, used motor oils, a waste lube oil from a motor workshop, a regular diesel oil and a biodiesel blend, etc. The chemical fingerprints such as the abundance and distribution profiles of total petroleum hydrocarbon, polycyclic aromatic hydrocarbons (PAHs), particularly the higher molecular pyrogenic PAHs, and biomarkers indicate that the used and the waste lube oils are mixtures of mainly lube oil and a small amount of diesel type fuel. The presence of C16 to C20 fatty acid methyl esters (FAME) with the dominance of C16:0 and C18:1 isomers suggests that the used and the waste lube oils both contain residual palm oil-based biodiesel.

In 1985, the MV Manolis L ran aground and sank on Blow Hard Rock near the Change Islands in Notre Dame Bay, Newfoundland and Labrador. From 2013 to 2016, the Canadian Coast Guard (CCG) conducted several operations to trap and recover oil leaking from the sunken tanker. Seventeen samples were collected between 2013 and 2016 from the sunken vessel to identify the oil source and evaluate the evolution of the physicochemical properties of the oil trapped in the sunken vessel. Most of the oils collected in 2016 and all the oils collected from 2013 to 2015 were heavy fuel oils that had not undergone significant weathering (Group 1). Two oils collected in 2016 were identified as diesel oil in terms of their hydrocarbon composition (Group 2). Other two oils collected in 2016 (Group 3) had similar hydrocarbon properties as Group 1 heavy fuel oils; however, they had greater quantities of biomarkers and GC-detectable total petroleum hydrocarbons (TPH) in the >n-C34 fraction and a lower quantity of resolved components, such as n-alkanes and PAHs. Detailed chemical fingerprinting pointed to these samples as being heavy fractions of Group 1 oils that had settled into a residual layer or had weathered through evaporation loss. Neither the heavy fuel oil nor diesel oil experienced significant loss through photo-oxidation and biodegradation, even 31 years post-sinking. Physical deposition, evaporation, and/or dissolution, especially deposition, were the main factors altering the physicochemical properties of the heavy fuel oil trapped in the sunken vessel.

With the increasing use of biodiesel and its blends with petroleum fuel, the corresponding environmental issues also occur during its production, application and transportation. The photolysis behavior for biodiesel and the impacts of biodiesel on the photo-oxidation of petroleum hydrocarbons in simulated freshwater was studied by irradiated with ultra violet (UV) and simulated sunlight in the present study. The results indicated that the photolysis rates of fatty acid methyl esters (FAMEs) were mainly depended on their degree of saturation, slightly on water matrices and the initial concentration of biodiesel, regardless of biodiesel sources. Similar results were observed for total organic carbon (TOC) removal rates; however, TOC removal rates were slightly dependent on the initial concentration of biodiesel. The presence of humic acid and pyrogallic acid or lake water matrices slightly inhibited the removal rates of TOC. The photolysis rates of individual petroleum hydrocarbons with and without the presence of biodiesel followed similar rules. In brief, alkanes with light molecular weights were transformed faster than those with heavy molecules, the removal of polycyclic aromatic hydrocarbons (PAHs) were more significantly than alkanes, and the removal of alkylated PAHs (APAHs) increased concurrently with the alkylation level in each family. The presence of biodiesel only inhibited the photolysis of some heavy alkanes and PAHs, not for all other petroleum hydrocarbons. Biodiesel, as a surfactant-like material, could stabilize small oil droplets initially formed by agitation, therefore, these droplets experience longer lifetimes in the water phase before re-aggregating into larger globules and rising to the surface. The apparent solubility of petroleum hydrocarbons, especially for those with heavier molecular weights, has been enhanced in the presence of FAMEs. In this scenario, light needs to penetrate water phase to degrade these targets compared with diesel alone. The direct contacting opportunities between UV light and targets, and radicals produced to attack targets were reduced, which finally resulted in the inhibited photolysis rates of some heavy molecular weight hydrocarbons.

The present study investigated the storage stability of two commercially available biodiesels and their blends with diesel spiked with different impurities, which were stored at two different temperatures (15 and 40 °C) with air tight and light screen. These samples were periodically monitored during the whole storage period by measuring a number of properties, such as acid value (AV), induction time (IT) and composition of fatty acid methyl esters (FAMEs). It was found that (1) acid values increased but induction time decreased with the extension of storage for all samples without copper; however, both IT and AV values kept nearly constant for all samples with copper; (2) the presence of water did not contribute significantly to the degradation of all tested samples over time; and (3) higher temperature (40 °C) was favorable to the degradation of unsaturated FAMEs, accompanying with the altered acid values and induction time in comparison with the same samples stored at 15 °C. Faster degradation of FAMEs in blended samples than those in pure biodiesels may be partially due to the diluting effects of antioxidants in biodiesel. However, the presence of any impurities did not affect the degradation rates of FAMEs, which was not in agreement with the above mentioned AV and IT time series. This suggested that the addition of copper affected the measurement of AV and IT. Therefore, for samples with copper, FAME profiles can represent their quality more appropriately than IT or AV.