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The occurrence, spatial distribution and source of petroleum-related hydrocarbons, and the degree of weathering of Arrow oil residues persisting on the shoreline of Chedabucto Bay, Nova Scotia, were assessed. The hydrocarbons assessed included total petroleum hydrocarbons (TPH), n-alkanes from n-C9 to n-C40, petroleum biomarkers like terpanes, hopanes and steranes, non-alkylated polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues (APAHs). Trapped Arrow oil in the sunken tanker has not experienced any marked weathering. The collected environmental samples could be classified into three groups. Group 1 samples were oil free identified by low TPH, highly resolved fractions, a predominantly biogenic source of n-alkanes, and trace amounts of petroleum biomarkers probably from the historical (1970) oil spill. Group 2 samples had higher TPH and the other targets than Group 1 samples. The mixed petrogenic and terrestrial plant inputs were the source of n-alkanes, while the pattern of APAHs indicated that their source varied from site to site, being either recently released petroleum or Arrow oil residues. Group 3 samples mainly contained oil residues from Arrow oil spill, having very high levels of TPH, APAHs and biomarkers; however, most samples were free of n-alkanes. Group 3 samples were mostly found on the southern shoreline of Chedabucto Bay, especially in the upper to middle intertidal zone of the shorelines characterized by mixed pebble/cobble/boulders. The extent of weathering of n-alkanes and APAHs showed no relation to each other, although n-alkanes were depleted more fully than APAHs for most of the oil residues. Thus, various natural attenuation processes, especially for microbial degradation, have contributed to the aging of these oil residues. The degree of weathering varied with different environmental conditions.

The Fraser River Delta is a unique and dynamic region supporting the diverse ecosystems and habitats in the Canadian West Coast. Total petroleum hydrocarbons (TPH), n-alkanes, petroleum biomarkers, and polycyclic aromatic hydrocarbons (PAHs) were analyzed for the intertidal sediments taken from the shorelines of the Delta area, British Columbia, Canada, to establish the baseline background data. Most of the sampling sites had low TPH (< 40 μg/g); only two samples had TPH from 100 to 150 μg/g. Mainly biogenic n-alkanes were present in all sites. Non-detectable to trace amounts of petroleum biomarkers were found at most sites. Mixed pyrogenic and petrogenic inputs contributed to the presence of PAHs at most sites. PAHs are not present in amounts anticipated negative effects to benthic organisms in all sampling sites, except that benzo (a) pyrene (BaP) from the upper intertidal zone (UIZ) of Burnaby Fraser Foreshore Park may have possible adverse biological effects.

2017-182 The dispersal and weathering processes of crude and fuel oils have been studied for decades and significant scientific information has been published. However, the fate and behaviour of spilled nonconventional crude oil such as diluted bitumen products are less well understood. There is concern that a spill of the oil sands diluted bitumen may come into contact with marine shorelines as it is transported throughout Canada. There is uncertainty related to the fate of spilled diluted bitumen and potential interactions with shorelines. A Shoreline Oil Spill Research and Development Program was undertaken by Environment and Climate Change Canada (ECCC). In 2013, a 3-year study was initiated and focused on the marine shorelines of northern British Columbia (BC). Four field campaigns were conducted along the entire length of coast throughout the Douglas and Granville channels as well as Banks and Haida Gwaii islands. The field campaigns were used as an opportunity to develop and employ a new approach to collect and compile an extensive pre-spill baseline dataset. Data included an aerial survey with high definition video and a ground survey of representative shorelines where samples were collected and analyzed for petroleum hydrocarbons, carboxylic acid, pesticides, heavy metals, calcium carbonate and sediment grain size. Baseline levels of hydrocarbons in the sediment of the study areas were estimated based on the analysis of total petroleum hydrocarbons (TPH), n-alkanes ranging from n-C9 to n-C40, petroleum related biomarkers such as terpanes and steranes, polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues (APAHs).

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.

Total petroleum hydrocarbons (TPH), n-alkanes, petroleum biomarkers, and polycyclic aromatic hydrocarbons (PAHs) were analyzed in the intertidal sediments of Burrard Inlet, Vancouver, British Columbia, Canada. Most of the sampling sites had low TPH (40 μg/g). Only 10% of sampling sites, located nearby a harbour and densely populated areas, had relatively high TPH (260 μg/g). Main biogenic n-alkanes were present in all the sites, except for the main petrogenic input in the sample from the upper intertidal zone (UIZ) of the Maplewood Mudflats. Most sites had trace amounts of petroleum biomarkers. Mixed pyrogenic and petrogenic inputs contributed to PAHs at most sites. PAHs did not show potential toxicity to benthic organisms at most sites; however, possible negative effects from some of the detected PAHs were found for the samples from the UIZs of the Maplewood Mudflats and Labour View Park, and from the lower intertidal zone (LIZ) of Gates Park.

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.

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.