The well-characterized Alberta Sweet Mixed Blend oil and several other oils which are commonly transported in Canada were physically weathered and then incubated with a defined microbial inoculum. ...The purpose was to produce quantitative data on oil components and component groups which are more susceptible or resistant to biodegradation, and to determine how oils rank in relation to each other in terms of biodegradation potential. The biodegraded oils were characterized by quantitative determination of changes in important hydrocarbon groups including the total petroleum hydrocarbons, total saturates and aromatics, and also by quantitation of more than 100 individual target aliphatic, aromatic and biomarker components. The study reveals a pattern of distinct oil composition changes due to biodegradation, which is significantly different from the pattern due to physical or short-term weathering. It is important to be able to distinguish between these two forms of loss, so that loss due to weathering is not interpreted as loss due to biodegradation in the laboratory or in the field. Based on these findings, the oil composition changes due to biodegradation can be readily differentiated from those due to physical weathering. To rank the tested oils with respect to biodegradability, losses in total petroleum hydrocarbons and aromatics were used to calculate biodegradation potential indices, employing equations proposed by Environment Canada and the US National Oceanic and Atmospheric Administration. The different methods produced very similar biodegradation trends, confirming that patterns of oil biodegradability do exist.
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.
Factors affecting oxidation stability for several commercially available biodiesels were primarily investigated by acid value (AV) and induction period (IP) evaluations in this study. It was found ...that the measured IP at different storage time points were somewhat dependent on the saturated degree of fatty acid methyl esters (FAMEs), the corresponding measured AV scattered randomly. Generally, AV increased and IP decreased after one year of storing in a dark cold room in an air‐tight tank. Solvents (methanol, acetone and water) did not show a contribution to altering IP. Metals (copper and lead) showed the strongest detrimental effects to oxidative stability although somewhat depending on the particle size and oxide coating thickness, however, aluminum alloy and steel were not the case. Among the antioxidants, pyrogallol (PY) was the best in enhancing IP with a concentration of less than 3000ppm, however, tert-butylhydroquinone (TBHQ) was the best after 3000ppm, followed by propyl gallate (PG), butylated hydroxyanisole (BHA), 3,5-di-tert-butyl-4-hydroxyltoluene (BHT), and α-tocopherol. The appropriate dosage of PY was also evaluated to achieve the specified IP regulated by EN-14112 for samples with copper or lead contamination.
► Induction period (IP) not acid value (AV) depended on the saturated degree of FAME. ► AV increased but IP decreased after one year storage in -4°C in air tight tanks. ► Cu and Pb showed strong catalytic effects on deteriorate the quality of biodiesels. ► Solvents and metals (steel and aluminum) did not alter IP significantly. ► Selective antioxidants extended the IP of biodiesels with/without metal presence.
In this study, the water accommodated and particle-laden hydrocarbon species, and the toxicity of the aqueous phase after oil-sediment interactions by varying the weathering states of diluted bitumen ...(Cold Lake blend (CLB)), oil type from light to heavy, and sediment type. Compared to the original oils, the sediment-laden total petroleum hydrocarbons (TPH) contained fewer hydrocarbons in the carbon range <C10, comparable contents in C10–C16 range, higher contents in both the C16–C34 and >C34 range. Sediment-laden oil amounts generally decreased with an increased viscosity and asphaltene content of the test oils, as well as with increased sediment particle size. The presence of sediments significantly decreased the oil accommodated in water due to the formation of oil particulate aggregates (OPA) after mixing and settling. Less water accommodated TPH and polycyclic aromatic hydrocarbons (PAHs) were observed for weathered CLB products. However, oil and sediment types did not clearly affect the water accommodated TPH and PAHs. Light molecular PAHs and their alkylated congeners accounted for most of the water accommodated PAH congeners. A microtoxicity test demonstrated that with or without sediment, and regardless of sediment type, the toxicity of the water phase did not change significantly. Light oil of Alberta sweet mixed blend (ASMB) had the highest toxicity, followed by fresh CLB, and then all other oils, suggesting that ASMB and fresh CLB had relatively higher levels of light toxic components dissolved in the water phase compared with the other tested oils.
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•Sediment-laden TPH contained fewer <C10, but higher C16–C34 and >C34 range hydrocarbons.•Increased oil viscosity, asphaltene content, and sediment size decreased sediment-laden TPH.•Less water accommodated TPH and PAHs were observed for weathered CLB products.•Oil and sediment types did not clearly affect the water accommodated TPH and PAHs.•Toxicity of the water phase did not vary with sediment type, but vary with oil type.
Total petroleum hydrocarbons (TPH), n-alkanes, petroleum-related biomarkers of terpanes and steranes, and polycyclic aromatic hydrocarbons (PAHs) were analyzed in the intertidal sediments in the Bay ...of Fundy, Nova Scotia/New Brunswick, Canada. Sites close to the harbour and more densely populated areas had higher TPH levels than other pristine areas. n-Alkanes presented a typical single bell-shape in n-C16 to n-C35 range and an obvious odd to even carbon preference. Most sites had trace amounts of petroleum biomarkers. Abundant non-alkylated PAHs and lower amounts of alkylated PAHs represented the major input of the incomplete combustion of solid (e.g., coal, coke, biomass, and coal tar) and liquid fuels. The toxicity estimation for PAHs indicates that they did not have potential toxicity to benthic organisms at most sampling sites. However, possible to probable negative effects from the measured PAH concentrations were found for the two samples from Courtenay Bay and Saint Andrews.
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•Trace amounts of petroleum hydrocarbons were present in most sample sites within the Bay of Fundy.•Terrestrial plant inputs were the major source of n-alkanes.•Incomplete combustion of fossil liquid and solid fuels was the main source of PAHs.•Only PAHs in a few sites of Courtenay Bay and Saint Andrews had negative impact on benthic organisms.
The ability to characterize the composition of emerging unconventional Bakken tight oil is essential to better prepare for potential spills and to assess associated environmental concerns. The ...present work measured and compared the physical and chemical properties of Bakken crudes with conventional crude oils from various regions and different types of refined petroleum products. The physicochemical properties of Bakken crude are overall similar to those of conventional light crudes. The Bakken crude consists of high concentrations of monoaromatic hydrocarbons and alkylated PAHs with a clear dominance of the alkylated naphthalene homologues followed by the phenanthrene series. Its pyrogenic index (PI) values are considerably lower than typical conventional crude oils. The Bakken crude oils in this study exhibit a low abundance of petroleum biomarker such as terpanes, steranes and diamondoids and bicyclic sesquiterpanes. Since tight oil from the Bakken region is produced from low-permeability formations, variations in abundance and diagnostic ratios of common target petroleum hydrocarbons were found among these oils.
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•Integrated fingerprinting analysis and data interpretation to Bakken tight oil.•Similar physicochemical properties as conventional light crude oil.•High concentration of alkylated PAHs while a very low pyrogenic index.•Low petroleum biomarker terpanes and steranes as well as bicyclic sesquiterpanes.•Variations in abundance and diagnostic ratios of hydrocarbons among tight oils.
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•Diluted bitumen experienced similar photolytic trends but decreased removal efficiencies compared to light crude oil.•Aromatics were most photosensitive, followed by n-alkanes, then ...biomarkers.•Summer exposure led to higher photolysis than winter.•The differences of PAHs structure did not significantly affect their photolytic rates.
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.
Two types of diluted bitumen (dilbit) and a light crude oil spiked onto the surface of saltwater were irradiated with natural solar light in Ottawa to assess the impact of sunlight to the fate of ...oxygenated intermediates. Oxygenated components, including carbonyl polycyclic aromatic hydrocarbons (PAHs) and acidic polar fractions (naphthenic acid fraction compounds, NAFCs), were identified after periods of solar exposure under both winter and summer conditions. Carbonyl PAHs and NAFCs were formed in both seasons; however, light crude and summer irradiation produced higher abundance of them than dilbits and winter exposure. The formed NAFCs were abundant with the congeners containing a heteroatom of oxygen only (Oo species), accompanied by the minor amounts of sulfur- and nitrogen-containing acids. The produced Oo species were predominant with the congeners with light molecular weight, high degree of saturation and heavy oxygen numbers. For both carbonyl PAHs and NAFCs, their abundance continually increased throughout the period of winter exposure. In the summer, some carbonyl PAHs and all Oo species increased during the early exposure period; then they decreased with continued exposure for most oils, illustrating their transitional nature. Oxygenated intermediates thus appear to have been created through the photo-oxidation of non-to medium-polar petroleum hydrocarbons or the intermediates of aldehydes or ketones (O1). Oil properties, the duration of exposure, exposure season and the chemical structure of these intermediates are critical factors controlling their fate through photo-oxidation. The observed chemical changes highlight the effects of sunlight on the potential behavior, fate and impact of spilled oil, with the creation of new resin group compounds and the reduction of aromatics and saturates. These results also imply that the ecological effects of spilled oil, after ageing in sunlight, depend on the specific oil involved and the environmental conditions.
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•Photo-oxidation formed oxygenated intermediates, especially in summer exposed light oil.•Oo species were dominant in the formed NAFCs, accompanied by minor S-, N-containing congeners.•Oo species after solar irradiation shifted to less carbon number, higher degree of saturation and oxygen numbers.•The fate of these oxygenated components depends on oil property, exposed time and seasons, and their own chemical structure.
Oil properties, exposure time, the time of year for solar exposure and the chemical structure of oxygenated intermediates all play critical roles in controlling the fate and behavior of oxygenated intermediates derived through photo-oxidation.
•Acid values increased but induction time decreased for samples without copper.•Copper affected the measurement of acid value and induction time.•Water did not significantly alter acid values and ...induction time for all samples.•Presence of any impurities did not affect the degradation rates of FAMEs.•FAMEs in blended samples degraded faster than that in pure biodiesels.
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.
The occurrence, source and ecological assessment of baseline hydrocarbons in the intertidal zone along the northern British shoreline were evaluated based on analyzing total petroleum hydrocarbons ...(TPH), n-alkanes, petroleum related biomarkers such as terpanes and steranes, and polycyclic aromatic hydrocarbons (PAHs) including non-alkylated and alkylated homologues (APAHs). The TPH levels, n-alkanes, petroleum biomarkers and PAHs in all the sampling sites, except for Masset Harbor/York Point at Gil Island were low, without obvious unresolved complex mixture (UCM) and petroleum contamination input. Specifically, n-alkanes showed a major terrestrial plants input; PAHs with abundant non-alkylated PAHs but minor APAHs showed a major pyrogenic input. However, obvious petroleum-derived hydrocarbons have impacted Masset Harbor. A historical petroleum input was found in York Point at Gil Island, due to the presence of the low level of petroleum biomarkers. Ecological assessment of 13 non-alkylated PAHs in Masset Harbor indicated no potential toxicity to the benthic organisms.
•Except for Masset harbor, n-alkanes in all sampling sites were mainly terrestrial plants input.•Petroleum biomarkers were only present in Masset harbor and York Point in Gil Island.•PAHs were predominantly pyrogenic input in all the sampling sites.•Masset harbor had recent petroleum input; York Point in Gil Island had historical petroleum input.•PAHs in Masset harbor had no potential toxicity to the benthic organisms.
