Identification of Spilled Oil from the MV Marathassa (Vancouver, Canada 2015) Using Alkyl PAH Isomer Ratios

The content and composition of organic compounds in the bottom sediments of the Norilsk-Pyasina water system one year after the accidental spill of diesel fuel

One year after the emergency diesel fuel spill in Norilsk, hydrocarbon concentrations in bottom sediments of the Norilsk-Pyasina water system decreased. However the average concentrations of hydrocarbons in surface sediments decreased in the same sequence (μg/g) as in 2020: the mouth of the Ambarnaya R. (835, σ = 1788) > Bezymyanny Cr.-the Daldykan R.-the Ambarnaya R. (306, σ = 273) > the Pyasina R. (23, σ = 20) > the Pyasino Lake (12, σ = 8). Concentrations decreased due to degradation of low molecular weight hydrocarbons. The content of polycyclic aromatic hydrocarbons in 2021 also changed in a smaller range (0-1027 ng/g) than in 2020 (0-3865 ng/g). Petroleum origin of polycyclic aromatic hydrocarbons in the sediments of the Ambarnaya R. (including the mouth), Bezymyanny Cr. and the Daldykan R. is confirmed by the dominance of alkylated naphthalene homologues in their composition. Hydrocarbons accumulation in some layers of the sedimentary column is caused not only by the spill of diesel fuel, but also by the organic matter from the surrounding swamps, from wetlands and floodplain lakes, as well as by the burial of the surface layer by the 2021 flood.

Development and testing of a 2D offshore oil spill modeling tool (OSMT) supported by an effective calibration method

An Oil Spill Modeling Tool (OSMT) has been developed in this study to predict the transport and fate of oil spills resulting from surface releases. Particularly, the Kullback-Leibler (KL) divergence method is adopted as a performance metric for the first time to formulate a calibration framework for spill trajectory prediction (STP) from the Lagrangian transport model (LTM). By finding the candidate with minimal KL divergences from modeling scenarios using designed parameter combinations, the prediction discrepancy between simulated trajectories of the LTM and oil slicks detected from satellite images is reduced. The developed approach has been evaluated through a comparison analysis between OSMT and Operational Oil Modeling Environment (GNOME) model. Subsequently, a real case study is conducted to examine the applicability and effectiveness of the OSMT. The study results indicate that OSMT can provide reliable spill trajectory simulations, and the KL divergence-based calibration method is effective in calibrating the oil spill LTM.

Hydrocarbon pollution in the waters and sediments of the Kerch Strait

The results of studying the content and composition of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons in the suspended particulate matter of surface waters and in the surface layer of bottom sediments in 2019-2021 in the Kerch Strait in comparison with earlier studies in other areas of the Black Sea (Theodosia Gulf, Tuapse area, Coastal waters of the Crimean Peninsula, Big Sochi, Central part of the Sea) are presented. Despite the high concentrations of aliphatic hydrocarbons (especially in the waters of the strait itself: 28-254 on average 87 μg/L. The highest content of aliphatic hydrocarbons was confined to the cross-section through the Kerch Strait. Accumulation of aliphatic hydrocarbons, as well as the suspended particulate matter, occurs in the western part of the Strait, which is associated with the predominant wind direction and coastal orography. The composition of alkanes did not correspond to the smooth distribution of homologues characteristic of oil. Their distribution was bimodal in most samples, which may indicate a mixed genesis of alkanes. Among the low-molecular-weight alkanes either even numbered autochthonous alkanes n-C₁₆, C₁₈, C₂₂, arising during the microbial transformation of aliphatic hydrocarbons, or n-C₁₇, indicating the inclusion of phyto- and zooplankton alkanes, prevailed. Despite the different sources of hydrocarbons input, the distribution of the total concentrations of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons basically coincided. Polycyclic aromatic hydrocarbons composition was dominated by fluoranthene and pyrene, which are formed in high-temperature combustion processes Low values of the Σnaphthalenes/Phen ratio (0.05-0.11) may indicate an insignificant inclusion of petroleum polyarenes. In contrast to suspension of surface waters, the highest content of hydrocarbons in the surface sediments was found not in the strait, but at stations in areas with aleurite-pelitic sediments, which is due to the pattern of currents in these areas and the higher sorption capacity of finely dispersed sediments. The average C_org content in July 2020, was 1.8 times lower (0.34%) than in September 2019 (0.63%), and aliphatic hydrocarbons, on the contrary, was 2.2 times higher (47 μg/g) than in April 2019 (21 μg/g). In surface sediments the maximum concentration of aliphatic hydrocarbons was established in July 2020 (233 μg/g), and the highest average content in July 2021 (58 μg/g). This area is also associated with higher concentrations of aliphatic hydrocarbons in the composition of C_org -≥1%. The composition of alkanes in surface sediments differed from their composition in suspension. The ratio of low-to-high molecular weight homologues (L/H = 0.08-0.54) was lower and the odd-to-even ratio (CPI = 1.19-4.58) was higher than in particulate matter. Due to the coarse composition of sediments, the content of polycyclic aromatic hydrocarbons in their surface layer was lower (0-631 ng/g) compared to other areas of the Black Sea. In their composition, along with fluoranthene and pyrene, methylated naphthalene homologues also belonged to the dominant compounds. Correlation analysis of individual polyarenes, as well as factor analysis, indicates their mixed genesis oil + pyrogenic, with the preference of the latter in most samples. The entry of pollutants into the marine environment increases the hydrocarbons content in water and bottom sediments, creating a modern hydrocarbon background.

Occurrence, characterization, and ecological assessment of petroleum-related hydrocarbons in intertidal marine sediments of Burrard Inlet, Vancouver, British Columbia, Canada

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.

Evaluation of New Diagnostic Ratios of Naphthalenes and Fluorenes by Identifying Severely Weathered Oils Collected in Laboratory Simulations and Coastal Weathering Experiments

The composition and physical properties of spilled oil have great changes during the seriously weathering process. It brings great difficulties to the source identification of oil spill. So, the stable and trustworthy diagnostic ratios (DRs) for accurate identification of severely weathered spilled oils are very important. The explosion of Sinopec pipeline happened on November 22, 2013 at Qingdao, China. Local beaches at Jiaozhou Bay were polluted by spilled oils. We have collected original spilled oil samples from an area free from human interference near the oil leakage point after the accident. Synchronized with actual beach weathering, laboratory experiments were conducted to simulate oil weathering for 360 days by using the collected original spilled oil samples. Based on the t test and the repeatability limit method, 65 DRs of naphthalenes and fluorenes were screened. Fifteen DRs, namely, C2Nap/(C2Nap + C3Nap), C2Nap/(C2Nap + C4Nap), C2Nap/total Nap, C3Nap/(C3Nap + C4Nap), C3Nap/total Nap, C4Nap/total Nap, C2Flu/(C2Flu + C3Flu), C2Flu/total Flu, C2Nap/(C2Nap + Flu), C2Nap/(C2Nap + C1Flu), C2Nap/(C2Nap + C2Flu), C2Nap/(C2Nap + C3Flu), C3Nap/(C3Nap + Flu),C3Nap/(C3Nap + C1Flu), total Nap/(total Nap + total Flu), have maintained remarkable stability during the simulated weathering experiments and field weathering process. These stable ratios can retain the characteristics of oil source during weathering. They are very beneficial to improve the accuracy of identifying the source of severely weathered oil and can be used as an effective supplement to existing index system for source identification.

Evaluation of diagnostic ratios of phenanthrenes and chrysenes for the identification of severely weathered spilled oils from the simulation weathering and the Sinopec pipeline explosion at Huangdao, 2013

The composition and physical properties of spilled oil undergo great changes during a serious weathering process. This causes great difficulties for identifying the source of an oil spill. So stable and trustworthy diagnostic ratios (DRs) for the accurate identification of severely weathered spilled oils are very important. An explosion in the Sinopec pipeline happened on November 22, 2013 at Qingdao, China. Local beaches at Jiaozhou Bay were polluted by spilled oils. After the accident we collected original spilled oil samples from an area free from human interference near the oil leakage point. Synchronized with actual beach weathering, laboratory experiments were conducted to simulate oil weathering for 360 days by using the collected original spilled oil samples. Based on the t-test and the repeatability limit method, 46 diagnostic ratios (DRs) of phenanthrenes and chrysenes were screened. 18 DRs maintained remarkable stability during the simulated weathering experiments and field weathering process. These stable ratios can retain the characteristics of the oil source during weathering. They are very beneficial for improving the accuracy of identifying the source of severely weathered oil and can be used as an effective supplement to the existing index system for source identification.

The composition and physical properties of spilled oil undergo great changes during a serious weathering process.

Marine Environmental Emergencies in the North Pacific Ocean: Lessons Learned from Recent Oil Spills

Increasing marine vessel traffic, and oil and gas exploration and development throughout the North Pacific basin brings increasing risks of oil spills. Recognizing the serious challenges presented to response authorities, this Special Issue was organized by the North Pacific Marine Science Organization to provide an introduction to the current state of scientific understanding regarding the environmental effects of oil spills. Because interactions of spilled oils with biota and their habitats are complex, the most serious environmental damages from these spills are not necessarily those of greatest immediate concern by the public. Our overarching goal for this Special Issue is to provide an efficient introduction to the most important ways that oil spills can harm biota, habitats, and ecosystems through invited, targeted mini-reviews augmented by original research articles. We provide a brief background on the challenges posed by large oil spills to response authorities, summarize findings from the articles published in this Special Issue, and highlight some key research needs.