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Burn residues collected after large scale experimental in situ burns performed in the North Sea were characterised with emphasis on chemistry and acute toxicity. Low-energy water accommodated fractions (WAFs) of three marine fuels (Ultra Low Sulphur Fuel Oil (ULSFO), bunker oil (IFO180), and marine gas oil (MGO) and their field-generated residues from in situ burning (ISB). were prepared to evaluate the potential impact of ISB residue to the environment. The toxicity effects on primary consumers were assessed by testing on early life stage (nauplii) of the marine copepod Calanus finmarchicus. Toxicity studies showed that ISB decreased the acute toxicity of the WAFs compared to the initial oils. WAF of MGO had highest toxicity, and ISB residue of MGO seems to be more toxic than WAFs of fresh ULSFO and IFO180. Additive toxicity expressed as toxic unit (TU) based on the chemical composition also indicated that the toxicity of WAFs from ISB residues were lower than for the initial oils. The 2−3 ring PAHs seem to contribute most to the TU. Overall, the three offshore burns reduced the total mass of PAHs in the water accommodated fractions by >90 % compared to the released unburned oils and caused a reduction of the acute toxicity to copepod nauplii.

There is an urgent call for contingency planning with effective and eco-friendly oil spill cleanup responses. In situ burning, if properly applied, could greatly mitigate oil in water and minimize the adverse environmental impacts of the spilled oil. Chemical herders have been commonly used along with in situ burning to increase the thickness of spilled oil at sea and facilitate combustion. These chemical surfactant-based agents can be applied to the edges of the oil slick and increase its thickness by reducing the water–oil interfacial tension. Biosurfactants have recently been developed as the next generation of herds with a smaller environmental footprint. In this study, the biosurfactant produced by Rhodococcus erythropolis M25 was evaluated and demonstrated as an effective herding agent. The impact of environmental and operational factors (e.g., temperature, herder dose, spilled oil amount, water salinity, and operation location) on its performance was investigated. A five-factor fractional design was applied to examine the importance of these factors and their impact on herding effectiveness and efficiency. The results of this study showed that higher temperature and a higher dose of herder could result in an increased oil slick thickness changing rate. Differences in water salinity at the same temperature led to the same trend, that is, the herding process effectively goes up with increasing herder–oil ratio (HOR). Further large-scale testing needs to be conducted for evaluating the applicability of the developed bioherder in the field. [ABSTRACT FROM AUTHOR]

Oil spills into the oceans cause irreparable damage to marine life and harms the coastal population of the affected areas. The main measures to be taken in response to an oil spill are to reduce the impact on marine life, prevent oil from reaching the shore through its recovery, and accelerate the degradation of unrecovered oil. Any environmental damage can be reduced if the spilled oil is removed from the water quickly and efficiently. Therefore, it is essential to know the treatment strategies for spilled oils. Several technologies are currently available, including booms, skimmers, in situ burning, use of adsorbents, dispersants/surfactants, and bioremediation. The selection of the type of treatment will depend not only on the effectiveness of the technique, but mainly on the type of oil, amount spilled, location, weather, and sea conditions. In this review, the characteristics of oil spills, their origin, destination, and impacts caused, including major accidents around the world, are initially addressed. Then, the main physical, chemical, and biological treatment technologies are presented, describing their advances, advantages, and drawbacks, with a focus on the use of green surfactants. These agents will be described in detail, showing the evolution of research, recent studies, patents, and commercialized products. Finally, the challenges that remain due to spills, the necessary actions, and the prospects for the development of existing treatment technologies are discussed, which must be linked to the use of combined techniques. [ABSTRACT FROM AUTHOR]

In situ burning (ISB) is discussed to be one of the most suitable response strategies to combat oil spills in extreme conditions. After burning, a highly viscous and sticky residue is left and may over time pose a risk of exposing aquatic biota to toxic oil compounds. Scientific information about the impact of burn residues on the environment is scarce. In this context, a comprehensive ISB field experiment with approx. 1000L IFO 180 was conducted in a fjord in Greenland. The present study investigated the toxicity of collected ISB residues to early life stages of zebrafish (Danio rerio) as a model for potentially exposed pelagic organisms. The toxicity of ISB residues on zebrafish embryos was compared with the toxicity of the initial (unweathered) IFO 180 and chemically dispersed IFO 180. Morphological malformations, hatching success, swimming behavior, and biomarkers for exposure (CYP1A activity, AChE inhibition) were evaluated in order to cover the toxic response on different biological organization levels. Across all endpoints, ISB residues did not induce greater toxicity in zebrafish embryos compared with the initial oil. The application of a chemical dispersant increased the acute toxicity most likely due to a higher bioavailability of dissolved and particulate oil components. The results provide insight into the adverse effects of ISB residues on sensitive life stages of fish in comparison with chemical dispersant application. [ABSTRACT FROM AUTHOR]

Chemical herders contract oil slicks floating on the water surface and will likely be a useful tool at high latitudes for condensing oil spills in ice laden waters for in situ burning. However, floating ice and other obstacles on the sea surface fracture the contracting oil slick and trap patches of oil, thus degrading herder performance and burning efficiency. Using Alaska North Slope crude oil and the herding agent OP-40, we performed laboratory scale experiments to investigate how a contracting oil slick interacts with multiple obstacles arranged at different packing densities and with a bottleneck-type gap between obstacles, with a focus on the fluid mechanics of this interaction. The surface and spatial distribution of the herded oil slick is optically measured over time, and particle image velocimetry is used to measure the oil slick flow around the obstacles. Obstacle groups containing large numbers of tightly packed obstacles acted collectively to trap large amounts of oil while widely spaced obstacles that are fewer in number retained smaller individual tails of oil that then break up via capillary instability. Small bottlenecks delayed the contraction of the herded oil slick and resulted in a jet of herder penetrating downstream of the gap whereas wider bottlenecks allowed faster contraction and thus more fragmentation of the herded slick. These results provided a greater understanding of how a contracting fluid film on the water surface interacts with and is fragmented by different types of obstacles and provide a foundation for future modeling efforts to better understand ice-herder-oil interactions. • The effect of multiple obstacles on herded oil slick contraction and fragmentation is investigated. • Particle image velocimetry is used to measure the oil slick flow around different obstacles. • Tight spacing between large numbers of obstacles trapped the herded slick more than wide spacing of fewer obstacles. [ABSTRACT FROM AUTHOR]

In situ burning (ISB) on open water can remove more than 85–90% of spilled oil making it a promising technology for an efficient oil spill response. The current study examines the burning behavior of an oil spill in the presence of ice, comparable to the Arctic environment. Alaska North Slope (ANS) crude oil with initial thickness varied from 0.5 to 1.5 cm in ice cavities with effective diameters of 28 and 110 cm and depths of 10–25 cm are studied. The experiments show that, overall, the average burning rate in an ice cavity is greater than that of a similar sized vessel or a pan. However, overall efficiency is much lower compared with ISB on open water. This is because of oil layer penetration horizontally into the ice, forming a pocket or a lateral cavity. Depending on initial conditions such as ullage, geometry of cavity and thickness of oil layer, 7–23% of the oil is trapped within the lateral cavity and thereby un-recoverable. The broader implications of the experimental results towards ISB in the Arctic are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • First application of nano Fe 2 O 3 to in-situ burning of spilled oil. • Fe 2 O 3 modifies temperature profile and enhances the burning efficiency of crude oil. • Iron oxide catalytically assists crude oil oxidation via a redox mechanism. • Crude oil properties impact the effectiveness of additives during in-situ burning. Oil spills in open waters are ongoing threats to the ecosystem, especially marine life. In situ burning (ISB) has been identified as one of the practical responses to these accidents. One of the challenges in applying ISB is the lower efficiency in the burning of heavy oil fractions. This systematic study investigated the feasibility of applying commercially available, inexpensive, and non-toxic iron oxide (Fe 2 O 3) as an additive for ISB of crude oils. Our results showed that Fe 2 O 3 nanoparticles with redox properties generate ionic oxygen species (found in the vicinity of surface defects), which catalyze the combustion reaction. Furthermore, Fe 2 O 3 addition could shorten the gap between the burning of light fractions and the heavy fractions of crude oils (the difference between low-temperature oxidation (LTO) and high-temperature oxidation (HTO) decreased from 88 to 36 degrees upon addition of Fe 2 O 3) and eliminate the endothermic distillation step (involved in the burning process), which in return improved the burning of heavy fractions. This supports the use of Fe 2 O 3 nanoparticles as an effective additive to enhance ISB, especially of light crude oils. This additive resulted in an increase in the burning efficiency of light crude oil by two folds. This study shares the first application of nanoparticles in ISB, revealing its unleashed potential for further developments by the scientific community. [ABSTRACT FROM AUTHOR]

Abstract: Troll B crude oil was weathered under Arctic conditions with different ice coverage: open water, 50% ice and 90% ice. Samples (100mL) were taken during the experiment and tested for ignitability in a burning cell. From each burning a residue sample was taken for analysis. The burning process removed the light compounds eluting before C13. No effect from the prior weathering time or the different ice coverage was seen in the burn residue composition. The content of selected Poly Aromatic Hydrocarbons (PAHs) was determined and it was noted that the concentration of PAHs with more than 4 rings were increased. The source origin of the PAHs was investigated by use of relative ratios of PAH isomers and indicated that some formation of PAHs was additionally taking place during burning. [Copyright &y& Elsevier]

Abstract: In situ burning of oil spills in the Arctic is a promising countermeasure. In spite of the research already conducted more knowledge is needed especially regarding burning of weathered oils. This paper uses a new laboratory burning cell (100mL sample) to test three Norwegian crude oils, Grane (asphalthenic), Kobbe (light oil) and Norne (waxy), for ignitability as a function of ice conditions and weathering degree. The crude oils (9L) were weathered in a laboratory basin (4.8m3) under simulated arctic conditions (0, 50 and 90% ice cover). The laboratory burning tests show that the ignitability is dependent on oil composition, ice conditions and weathering degree. In open water, oil spills rapidly become “not ignitable” due to the weathering e.g. high water content and low content of residual volatile components. The slower weathering of oil spills in ice (50 and 90% ice cover) results in longer time-windows for the oil to be ignitable. The composition of the oils is important for the window of opportunity. The asphalthenic Grane crude oil had a limited time-window for in situ burning (9h or less), while the light Kobbe crude oil and the waxy Norne crude oil had the longest time-windows for in situ burning (from 18h to more than 72h). Such information regarding time windows for using in situ burning is very important for both contingency planning and operational use of in situ burning. [Copyright &y& Elsevier]

Abstract: This paper compares the ignitability of Troll B crude oil weathered under simulated Arctic conditions (0%, 50% and 90% ice cover). The experiments were performed in different scales at SINTEF’s laboratories in Trondheim, field research station on Svalbard and in broken ice (70–90% ice cover) in the Barents Sea. Samples from the weathering experiments were tested for ignitability using the same laboratory burning cell. The measured ignitability from the experiments in these different scales showed a good agreement for samples with similar weathering. The ice conditions clearly affected the weathering process, and 70% ice or more reduces the weathering and allows a longer time window for in situ burning. The results from the Barents Sea revealed that weathering and ignitability can vary within an oil slick. This field use of the burning cell demonstrated that it can be used as an operational tool to monitor the ignitability of oil spills. [Copyright &y& Elsevier]

Abstract: In situ burning is an oil spill response option particularly suited to remote, ice-covered waters. The key to effective in situ burning is thick oil slicks. If ice concentrations are high, the ice can limit oil spreading and keep slicks thick enough to burn. In drift ice conditions and open water, oil spills can rapidly spread to become too thin to ignite. Fire-resistant booms can collect and keep slicks thick in open water; however, even light ice conditions make using booms challenging. A multi-year research project was initiated to study oil-herding surfactants as an alternative to booms for thickening slicks in light ice conditions for in situ burning. Small-scale laboratory experiments were completed in 2003 and 2005 to examine the idea of using herding agents to thicken oil slicks among loose pack ice for the purpose of in situ burning. Encouraging results prompted further mid-scale testing in 2006 and 2007 at the US Army Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, NH; at Ohmsett, the National Oil Spill Response Research & Renewable Energy Test Facility in Leonardo, NJ; and, at the Fire Training Grounds in Prudhoe Bay, AK. The non-proprietary hydrocarbon-based herder formulation used in these experiments proved effective in considerably contracting oil slicks in brash and slush ice concentrations of up to 70% coverage. Slicks in excess of 3mm thick, the minimum required for ignition of weathered crude oil on water, were routinely achieved. Herded slicks were ignited, and burned equally well in both brash and slush ice conditions at air temperatures as low as −17°C. The burn efficiencies measured for the herded slicks were only slightly less than the theoretical maximums achievable for equivalent-sized, physically contained slicks on open water. Successful meso-scale field trials of the technique were carried out in the Barents Sea off Svalbard in the spring of 2008 as one facet of a large joint industry project on oil spill response in ice co-ordinated by SINTEF. The larger field experiment involved the release of 630L of fresh Heidrun crude onto water in a large lead. The free-drifting oil was allowed to spread for 15min until it was far too thin to ignite (0.4mm), and then the hydrocarbon-based herder was applied around the slick periphery. The slick contracted and thickened for approximately 10min at which time the upwind end was ignited. A 9-minute long burn ensued that consumed an estimated 90% of the oil. From 2007 to 2009 experiments were carried out in the laboratory and at CRREL comparing the efficacy of herding agents formulated with silicone-based surfactants, herding agents formulated with second-generation fluorosurfactants, and the hydrocarbon-based herder. The results showed that the fluorosurfactant-based herders did not function better than the hydrocarbon-based herder; however, the new silicone surfactant formulations considerably outperformed the hydrocarbon-based herder. Most recently, experiments were conducted to determine if herding agents could: 1) improve skimming of spilled oil in drift ice; 2) clear oil from salt marshes; and, 3) improve the efficiency of dispersant application operations. [Copyright &y& Elsevier]

Oil spill clean-up measures using in situ burning can potentially result in seafloor contamination affecting benthic organisms. To mimic realistic exposure and measure effects, ovigerous Northern shrimp were continuously exposed for two weeks to the water-soluble fraction of oil coated on gravel followed by two weeks in clean seawater. North Sea crude oil (NSC) and field generated in situ burn residue (ISBR) of NSC were used (Low: 3 g/kg gravel, Medium: 6 g/kg gravel and High: 12 g/kg gravel). The concentrations of polyaromatic hydrocarbons (PAHs) in the water resulting from NSC were higher compared to ISBR. No mortality was observed in any treatment and overall moderate sublethal effects were found, mostly after exposure to NSC. Feeding was temporarily reduced at higher concentrations of NSC. PAH levels in hepatopancreas tissue were significantly elevated following exposure and still significantly higher at the end of the experiment in NSC High and ISBR High compared to control. Mild inflammatory response reactions and tissue ultrastructural alterations in gill tissue were observed in both treatments. Signs of necrosis occurred in ISBR High. No change in shrimp locomotory activity was noted from NSC exposure. However, ISBR exposure increased activity temporarily. Larvae exposed as pleopod-attached embryos showed significant delay in development from stage I to stage II after exposure to NSC High. Based on this study, oil-contaminated seafloor resulting from in situ burning clean-up actions does not appear to cause serious effects on bottom-living shrimp. [Display omitted] • Comparative toxicity of crude oil and field generated in situ burn residue (ISBR). • Oil and ISBR: No mortality, but minor gill damage also 2 weeks post-exposure. • Oil and ISBR: Elevated tissue levels of PAHs, also 2 weeks post-exposure. • Oil only: Transient reduction of adult feeding rate and delayed larval development. • ISBR less adverse effects than crude oil. [ABSTRACT FROM AUTHOR]

In situ burning (ISB) is an oil spill clean-up option used by oil spill responders to mitigate impacts on the marine environment. Despite advantages such as high efficiency and potential applicability for challenging areas such as the Arctic, the actual environmental side effects are still uncertain. Acute and sublethal effects of the water accommodated fractions (WAFs from 25 g oil/L seawater) of a pre-weathered North Sea crude (Oseberg Blend 200 °C+) and field generated ISB residue were evaluated on Northern shrimp (Pandalus borealis) larvae. The larvae were first exposed for 96 h to a serial dilution of seven concentrations, and then maintained for two weeks in clean seawater post-exposure. No acute (mortality) or sublethal effects (feeding, development, or growth) were detected in any of the ISB residue concentrations. Significant larvae mortality was found in the three highest concentrations of crude oil (96-h LC50:469 μg/L total petroleum hydrocarbon) but no sublethal effects were found in the surviving larvae post-exposure. This study indicates that applying ISB could mitigate acute impacts of spilled oil on shrimp larvae. [Display omitted] • Comparative toxicity of crude oil and in situ burn residue in shrimp larvae. • Crude oil exposure caused mortality but no sublethal effects. • No acute nor long-term effects found after exposure to the in situ burn residue. • Important contribution to Spill Impact Mitigation Assessment. [ABSTRACT FROM AUTHOR]

• Water-soluble petrogenic and pyrogenic organics were characterized using FTICR-MS. • Burning oil introduces oxidized and highly unsaturated organics into the water. • ISB greatly increases concentration of organics partitioning into the water phase. In situ burning is often used as a response method for oil slicks in the marine environment. This process however forms viscous tar-like residues that either float on the surface or sink through the water column, introducing organic species into the water phase. The interaction of this burn residue with the water phase also introduces dissolved organics into the water column. In this study, we conducted laboratory-scale experiments to characterize and compare the organic species entering the water phase from the petrogenic (fresh oil) and pyrogenic (burnt oil) input during oil spills. The oil and water-soluble organics were characterized using ultra-high-resolution mass spectrometry (FTICR-MS). The results show that burning strongly increases concentrations of oil-related constituents entering the water phase, due to transformation reactions producing oxidized organic species with higher water solubility. The pyrogenic water-soluble organics also showed a higher percentage of unsaturated compounds relative to the petrogenic fraction. The effect of these highly unsaturated and oxygenated organic species on oil spill fate and their ecosystem impacts is currently unknown. [ABSTRACT FROM AUTHOR]

We studied how exposure to oil spill response technologies affect marine microorganisms during Arctic winter and spring. Microorganisms were exposed to chemically dispersed oil (DISP), in situ burnt oil (ISB), and natural attenuated oil (NATT) in mesocosms from February to May. We subsampled the mesocosms and studied the effects of oil in laboratory incubations as changes in biomass of the major functional groups: bacteria, heterotrophic-nanoflagellates, dinoflagellates, ciliates, pico- and nanophytoplankton, and diatoms over two 14-day periods. In winter, the majority of polycyclic aromatic hydrocarbons (PAHs) remained encapsulated in the ice, and the low concentrations of PAHs in water led to minute changes in biomass of the investigated groups. In spring, however, when the PAHs were partially released from the melting ice, the biomass of many functional groups in DISP and NATT decreased significantly, while the changes in ISB were less pronounced. The overall biomass reduction, as observed in this study, could lead to a disrupted transfer of energy from the primary producers to the higher trophic levels in oil affected areas. • Oil remediation tools enhance growth of bacteria and heterotrophic nanoflagellates. • In situ burning has the least harmful effects on microbial community structure. • Chemical dispersant and oil weathering reduce microbial community biomass by 50%. [ABSTRACT FROM AUTHOR]