Sunken Tanker Research Articles

Occurrence and characterisation of naphthenic acid fraction components in oil residues and sediments stranded on the shoreline of Chedabucto Bay, Nova Scotia, Canada

In June 2016, oil residues and sediment samples were collected from the shoreline of Chedabucto Bay, Nova Scotia, Canada, at sites affected by the 1970 Arrow oil spill. This study aimed to investigate the occurrence, fate, and behaviour of oil components 45 years post-spill by analysing polar naphthenic acid fraction components (NAFCs) through high-performance liquid chromatography–high-resolution mass spectrometry (HPLC–HRMS). In all samples, the most abundant NAFC species were those having only oxygen as the heteroatom (Oo species, o indicating the number of oxygen atoms, from 1 to 8) and a high degree of saturation. NAFC species only containing two oxygen atoms (O2) accounted for 50–70% of all Oo species. The abundance of all remaining species was negligible compared with Oo species. NAFCs in most Arrow oil residues had higher levels of oxygen species than the oil remaining stored in the sunken tanker. Environmental sediment samples collected from near a marina away from the spill site contained a dominant biological, whereas all Arrow oil residues were mainly composed of NAFCs that are characteristic of petroleum. The abundance of NAFCs in the Arrow oil residues varied between sites, confirming that site-specific environmental conditions play a major role in controlling the fate and behaviour of oil components, including NAFCs.

Characterization of polycyclic aromatic hydrocarbons in the surface sediments around the sunken Sanchi oil tanker

The Sanchi oil tanker collision has attracted worldwide attention for its uniqueness in history. This study investigates the contamination level, spatial distribution, sources, and ecological risk level of polycyclic aromatic hydrocarbons (PAHs) present in the surface sediments collected from around the sunken tanker. The results indicated that the total PAH contents in the study area were in the range of 26.42–226.94 ngˑg−1, with an average of 106.86 ngˑg−1. The highest PAH concentration was observed at the station closest to the Sanchi wreckage, indicating potential PAH contamination due to the accident. The PAH ratios and statistical analysis revealed that the PAHs were mainly generated by coal and fuel oil combustion, with certain petrogenic inputs. The ecological risk assessment results suggested that adverse ecological effects to the benthic ecosystem due to PAH contamination was rare. However, long-term monitoring of the local sedimentary environment is highly recommended because of the prominent presence of high molecular weight PAHs.

Source identification and evolution of oils recovered from the MV Manolis L shipwreck

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.

A study of the 46-year-old Arrow oil spill: Persistence of oil residues and variability in oil contamination along Chedabucto Bay, Nova Scotia, Canada

Abstract 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.

Sanchi oil spill continues; impacts still unclear

Rough seas have begun to disperse oil spilled from a sunken tanker in the East China Sea. The spill’s total surface area has fluctuated in the past week from a high of 332 km2 on Jan. 21 to a report of 93 km2 on Jan. 25, according to China’s State Oceanic Administration. The Iranian tanker Sanchisank on Jan. 14 after colliding with a Chinese cargo ship and burning for over a week. It may be leaking heavy bunker fuel that was powering the vessel in addition to some of the 136,000 metric tons of ultralight crude oil, called condensate, that it was carrying. Undersea robots have detected a 35-m-wide triangular hole in the vessel, according to China’s Ministry of Transport. However, attempts to plug the hole or recover oil from the ship may be challenging because the condensate is highly flammable and explosive, and a weather system is expected to

A system of containment to prevent oil spills from sunken tankers

Worldwide tank spills represent 10% of the average annual input of oil in the sea. When such spills arise from wrecks at depth, neutralisation of environmental impacts is difficult to achieve. Extracting oil from sunken tankers is expensive, and, unfortunately, all of the oil cannot be extracted, as the Prestige case demonstrates. We propose an environmentally appropriate, cost-effective and proactive method to stop the long-term problem of leaks from sunken tankers similar to the Prestige. This method confines the wreck with a “sediment” capping of sepiolite mineral that emulates a natural sediment. A set of experiments and simulations shows that sepiolite has the characteristics necessary to accomplish the confinement of any current or future sunken tanker with minimal environmental perturbation.

Genome sequence of obligate marine polycyclic aromatic hydrocarbons-degrading bacterium Cycloclasticus sp. 78-ME, isolated from petroleum deposits of the sunken tanker Amoco Milford Haven, Mediterranean Sea

Cycloclasticus sp. 78-ME isolated from petroleum deposits of the sunken tanker “Amoco Milford Haven” (Gulf of Genoa, Ligurian Sea, Italy) could effectively degrade polycyclic aromatic hydrocarbons of up to five condensed rings. The genome of 78-ME was sequenced and analysed to gain insights into its remarkable degrading capacities. It comprises two circular replicons, the 2,613,078bp chromosome and the plasmid of 42,347bp, with 41.84% and 53.28% of the G+C content respectively. A total of 2585 protein-coding genes were obtained, and three large operons with more than fifteen enzymes belonging to four different classes of ring-cleavage dioxygenases were found.

Toxicity and phototoxicity of water-accommodated fraction obtained from Prestige fuel oil and Marine fuel oil evaluated by marine bioassays

Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Prestige in comparison to a standard Marine fuel oil were evaluated by obtaining the water-accommodated fraction (WAF) and using mussel Mytilus galloprovincialis and sea urchin Paracentrotus lividus embryogenesis bioassays, and copepod Acartia tonsa and fish Cyprinodon variegatus survival bioassays . Aromatic hydrocarbon (AH) levels in WAF were measured by gas chromatography. Prestige WAF was not phototoxic, its median effective concentrations (EC 50) were 13% and 10% WAF for mussel and sea urchin respectively, and maximum lethal threshold concentrations (MLTC) were 12% and 50% for copepod and fish respectively. Marine WAF resulted phototoxic for mussel bioassay. EC 50s of Marine WAF were 50% for sea urchin in both treatments and 20% for mussel under illumination. Undiluted Marine WAF only caused a 20% decrease in mussel normal larvae. Similar sensitivities were found among sea urchins, mussels and copepods, whilst fish were less sensitive. Unlike Marine WAF, Prestige WAF showed EC 50 values at dilutions below 20%, and its toxicity was independent of lighting conditions. The differences in toxicity between both kinds of fuel could not be explained on the basis of total AH content.

Satellite-derived sea surface height and sea surface wind data fusion for spilled oil tracking

An attempt is made to estimate the trajectory of the spilled oil from the sunken tanker Nakhodka occurred on January 2, 1997 in the Japan Sea by fusing two microwave sensor data, namely ERS-2 altimeter and ADEOS/NSCAT scatterometer data. In this study ‘fusion’ is defined as the method of more reliable prediction for the trajectory of spilled oil than before. Geostrophic current vectors are derived from ERS-2 altimeter and wind-induced drift vectors are derived from ADEOS/NSCAT scatterometer data These two different satellite-derived vectors are ‘fused’ together in the surface current model to estimate and evaluate the trajectory of spilled oil from the sunken tanker Nakhodka. The distribution of component of spill vector is mostly accounted for by the distribution of geostrophic velocity component during the study period with some discrepancies during March, 1997.

Submarine seals cracks in sunken tanker

Submarine seals cracks in sunken tanker