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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]

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.

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]

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 NSCHigh and ISBRHigh compared to control. Mild inflammatory response reactions and tissue ultrastructural alterations in gill tissue were observed in both treatments. Signs of necrosis occurred in ISBRHigh. 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 NSCHigh. 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.

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]

Shipments of Bakken crude oil by rail have increased in concert with the production of unconventional crude oil in the Williston Basin over the past 10 years, during which time multiple fiery train derailments resulted in tragic loss of life and/or environmental impacts. In this study the compositions of Bakken oil burn residues from a derailment fire(s) are compared to fresh and laboratory-evaporated Bakken crude oil. The absolute and hopane-normalized concentrations of n-alkanes, unsubstituted and substituted PAHs, and petroleum biomarkers and their percent depletions and enrichments (relative to hopane) are reported. Bakken oil burn residues lost 67–78% of their total chromatographable mass (C5 to C44) and exhibit chemical trends distinct from naturally-evaporated oil, including (1) the shape of their UCM profiles, (2) depletion of n-alkanes up to (at least) n-C30, (3) enrichment of priority pollutant (pyrogenic) PAHs, specifically favoring PAH isomers containing three or more linear aromatic rings (anthracene or benz[a]anthracene) or 5-member rings (fluoranthene or indeno[1,2,3-c,d]pyrene), and (4) depletion of some lower boiling petroleum biomarkers (C23-C25 tricyclic terpanes). Despite relative enrichment of most priority pollutant PAHs the absolute concentrations of both total PAH (TPAH50) and priority pollutant PAH (PPAH16) in the burn residues were depleted 69–78% and 41–48%, respectively, compared to fresh Bakken oil. These results demonstrate the changes and range of compositions among fresh, evaporated, and variably-combusted residues of Bakken crude oil, the latter of which are important in assessing the potential effect(s) of burn residues on the environment proximal to train derailment fires. [ABSTRACT FROM AUTHOR]

A parametric experimental study on melting of ice adjacent to liquids exposed to various heat fluxes from above was conducted in order to understand the role of liquid properties in formation of cavities in ice. In previous experiments related to in situ burning (ISB) of crude oil contained in ice, the convective motion in the fuel layer was identified as a key parameter determining the amount of the ice melting. An experimental setup was designed to measure the melting rate of the ice and penetration speed of the liquid similar to the lateral cavity formation problem observed in ISB experiments. Lateral cavity formation is identified as a key factor reducing the removal efficiency of ISB. The experiments were conducted in a transparent glass tray (70 mm × 70 mm × 45 mm) with a 20 mm thick ice wall (70 mm × 50 mm × 20 mm) placed on one side of the tray. Liquids in the tray (water, n-pentane, dodecane, n-octane, m-xylene, and 1-butanol) that were adjacent to the ice wall were exposed to varying heat fluxes mimicking flame heat feedback from a pool fire. The results of ice melting rate among different liquids were found to vary significantly. The exposure of the liquids to the radiative heat flux led to temperature difference between the liquid and the ice, thereby creating a heat transfer pathway towards the ice that provided the required energy for the melting. It is suggested that Marangoni-driven convection caused by the temperature gradient near the ice and below the free surface of the liquid is influential in the ice melting. A scaling analysis of the surface flow was undertaken to elucidate the influence of surface tension effect (Marangoni convection). It was found that the surface flow velocity obtained from the surface tension effect at the liquid free surface correlates well to the melting front velocity. [ABSTRACT FROM AUTHOR]

The influence of the initial fuel temperature on the burning behavior of crude oil pool fire in ice cavities was experimentally studied in this paper. The Bohai crude oil with initial fuel temperatures of 283, 293, and 303 K was burned in an initial ice cavity diameter of 6-8 cm. The mass loss rate exhibits three stages: the initial decrease stage, growth stage, and decay stage. The initial fuel temperature plays a significant role in the initial decrease stage. A heat transfer model is established to predict the mass loss rate, which agrees well with the experimental value. [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]

It is well known, that in case of oil spill, seabirds are among the groups of animals most vulnerable. Even small amounts of oil can have lethal effects by destroying the waterproofing of their plumage, leading to loss of insulation and buoyancy. In the Arctic these impacts are intensified. To protect seabirds, a rapid removal of oil is crucial and in situ burning could be an efficient method. In the present work exposure effects of oil and burn residue in different doses was studied on seabird feathers from legally hunted Common eider ( Somateria mollissima ) by examining changes in total weight of the feather and damages on the microstructure (Amalgamation Index) of the feathers before and after exposure. The results of the experiments indicate that burn residues from in situ burning of an oil spill have similar or larger fouling and damaging effects on seabird feathers, as compared to fresh oil. [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]

In situ burning is a method by which oil is burned at a spill site under controlled conditions, and this method is subject to increased interest due to its applicability in the Arctic. This paper reviews the literature regarding the characterization and environmental effects of burn residues in Arctic waters. The results of a systematic literature search indicate that only a very limited number of studies have arctic pertinence. From the review, it is also indicated that the properties and composition of the residues depend on the efficiency of the burning and the oil type. Furthermore, the studies within the frame of the literature search reach consensus that in situ burning may increase the concentrations of large poly-aromatic hydrocarbons (PAHs; high ring number) while reducing small PAHs (low ring number). There are very few toxicity studies of burn residues on aquatic and arctic organisms, and to enhance the knowledge base, more organisms as well as oil types must be studied. Furthermore, there is a lack of studies investigating the potential effect of sinking burn residues on benthic organism and the smothering effects of the more viscous burn residues on birds and other organisms related to the sea surface. More knowledge regarding environmental fate and effect of residues is crucial to complete a robust net environmental benefit analysis prior to an oil spill response operation in arctic waters. [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: The chemical composition and toxicity of a water soluble fraction (WSF) of oil versus the underlying water after in situ burning (ISB), has been studied in a laboratory experiment. A system for allowing water sampling after ISB was developed. Seawater samples and oil were collected prior to and immediately after ISB, and chemical analysis was conducted. The chemical characterization of the water showed that the disappearance of water soluble oil components during ISB was insignificant. Acute toxicity tests with the marine copepod Calanus finmarchicus and Microtox® bioassay was performed to establish LC50/EC50 values of the water. The results were compared with regular WAF systems with unburned weathered oil, and indicated no increase in toxicity in the underlying water after ISB. [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]

This research note summarizes Spartina alterniflora and Sagittaria lancifolia sensitivity to oiling and in situ burning of applied oil. Experimental plots (2.4 m × 2.4 m × 0.6 m) were constructed in salt and freshwater marsh habitats and South Louisiana Crude (SLC) applied (2 l m−2) to stems and leaves of marsh plants of oil and oil/burn treatment plots. Burning was initiated mid-August when winds were calm and a 15–25 cm floodwater layer covered the marsh substrate. Vegetative responses (stem density, height, carbon assimilation and biomass production) were measured for approximately one year following the in situ burns. Application of oil and burning of SLC only had short-term detrimental effects on salt and freshwater marsh vegetation. About one year after burns, vegetative responses measured in oiled and oiled/burned plots approached or exceeded control (no oil or burn) values. Field results suggest, under our experimental conditions, in situ burning of spilled oil in S. alterniflora and S. lancifolia marshes may be a remediation operation to consider. [Copyright &y& Elsevier]

In situ burning of inland and upland habitats is an alternative oil spill cleanup technique that, when used appropriately, may be more environmentally acceptable than intrusive manual, mechanical, and chemical treatments. There have been few published reports documenting the environmental effects of in situ burning in inland and upland habitats. Thus, this study, sponsored by the American Petroleum Institute, used two approaches to increase the knowledge base and improve the appropriate use of in situ burning: (1) detailed review of published and unpublished in situ burn case histories for inland and upland spills; and (2) summaries of fire effects and other information from the literature on fire ecology and prescribed burning. Thirty-one case histories were summarized to identify the state of the practice concerning the reasons for burning, favorable conditions for burning, and evaluations of burn effects. The fire ecology and effects summaries included information from the extensive knowledge base surrounding wildfire and prescribed burning (without oil) as a natural resource management tool, as well as fire tolerance and burning considerations for dominant vegetation types of the United States. Results from these two approaches should improve the application of in situ burning for inland and upland spills. [Copyright &y& Elsevier]

A combination of numerical modeling and large-scale experimentation has yielded a tremendous amount of information about the structure, trajectory and composition of smoke plumes from large crude oil fires. A numerical model, a large outdoor fire plume trajectory (ALOFT), has been developed at NIST to predict the downwind concentration of smoke and other combustion products. The model is based on the fundamental conservation equations that govern the introduction of hot gases and particulate matter from a large fire into the atmosphere. The model has been used to estimate distances from fires under of variety of meteorological and topographic conditions where ground level concentrations of smoke and combustion products fall below regulatory threshold levels. [Copyright &y& Elsevier]

This paper is a summary of the fundamentals that influence the window-of-opportunity for in situ burning of oil at sea. It is a discussion of the variables and factors that influence the capabilities and limitations of in situ burning of oil. This includes the requirements for ignition and sustained burning and the factors that influence the quantity of residue and burn efficiency and the use of emulsion breakers. [Copyright &y& Elsevier]

In situ burning is being utilized in the United States to remove oil from inland oil spills, usually when physical recovery is not feasible. Studies have found that habitats may recover from the effects of burning in less than a year under optimal conditions but recovery may take much longer. Policies authorizing the use of in situ burning across the US are very inconsistent. Some states use it routinely, but others do not allow it. Inland in situ burning can be a useful response tool and the federal government needs to issue more guidance to the states. Responders also need to collect more data on the environmental impacts of burning. [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]

The influence of different air entrainment conditions on the emissions of particulate matter from fire whirls was investigated by igniting a diesel fuel pool, 0.7 m in diameter, within a four-walled enclosure. Four different natural entrainment conditions resulted when gap sizes in the walls were varied between 0.35 and 0.65 m. In addition, three forced-entrainment conditions were created by holding the gap width constant and varying the air-entrainment velocity using fans positioned at each of the four gaps. The concentration of particulates was measured for these seven conditions, and one pool fire condition for comparison. For fire whirls under natural entrainment, the emission factor of total particulate matter, EF PM , was lower than that for pool fires, and decreased with increasing gap size. Fire whirls under mild levels of forced entrainment showed the lowest values of EF PM , but as the level of forced entrainment was increased, EF PM increased steadily to a value higher than that of pool fires. The reduction in EF PM is attributed to a combination of leaner stoichiometry and the interaction between the entrainment and the instantaneous burning rate. Thus, for a given pool diameter, an optimum value of entrainment velocity exists where the EF PM is lowest. Considerations for utilizing whirling flames to reduce airborne particulate emissions from in situ burning are discussed.

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]

The use of in-situ burning (ISB) as a clean-up response in the event of an oil spill has generated controversy because of unburned hydrocarbons and products of incomplete combustion left behind on an ISB site. These substances threaten marine life, both in the ocean and on the ocean floor. Treating crude oil as a multicomponent liquid fuel, this manuscript investigates the effect of carbon-based nanomaterials, acetylene black (AB) and multi-walled carbon nanotube (MWNT), on the combustion and flame characteristics of crude sourced from the Bakken formation (ND, USA). Sub-millimeter droplets of colloidal suspensions of Bakken crude and nanomaterials at various particle loadings were burned, and the process was captured with CMOS and CCD cameras. The resulting images were post-processed to generate burning rate, ignition delay, total combustion time, and flame stand-off (FSR) ratio data for the various crude suspensions. A maximum combustion rate enhancement of 39.5% and 31.1% was observed at a particle loading of 0.5% w/w acetylene black nanoparticles and 0.5% w/w multi-walled carbon nanotubes, respectively. Generally, FSR for pure Bakken was noted as larger than for Bakken with nanoparticle additives. These results are expected to spur further investigations into the use of nanomaterials for ISB crude oil clean-ups. • Carbon-based nanomaterials mixed into Bakken crude oil at various particle loadings. • Spherical sub-millimeter droplets burned using well-validated experimental setup. • Burning rate, ignition delay, total combustion time, flame standoff ratio compared. • Large increase in burning rate observed at small nanomaterial particle loadings. • Results expected to increase in-situ burning effectiveness as oil spill response. [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]

This study evaluated the feasibility of conducting in situ burning (ISB) using current technology on post-1967 major oil spills over 10000 barrels in North America and over 50000 barrels in South America and Europe. A diverse set of 141 spills representing various combinations of parameters affecting spill responses (e.g., spill size, oil type, weather conditions, sea temperature, and geographic location) wereevaluated using four "Phase I" criteria: Distance to populated area,oil weathering, logistics, and weather conditions. In Phase I, a spill that failed to meet one of the four criteria was considered an "unsuccessful" candidate for ISB. In total, 47 of the 141 spills passed the Phase I analysis. The potential effect of the plume on populated areas was the most significant of the four Phase I criteria; 59 of the 141 spills did not pass Phase I because the incident occurred near a sizable city. Spills that met all four criteria were further evaluated using a 'Phase II' analysis that applied additional criteria and considered individual spill circumstances to determine if the spill should be rated as a 'successful', 'marginal call', or 'unsuccessful' ISB candidate. Fourteen spills were ultimately determined successful in the Phase II analysis, and 12 were designated marginal calls. [ABSTRACT FROM AUTHOR]

During the period of 22 August/12 October 1998, seven commercial fire booms were involved in burn testing at the US Coast Guard Fire and Safety Test Detachment Facility in Mobile, Alabama in accordance withthe proposed protocol, American Society for Testing and Materials-F20. Four of the seven booms survived the test sequence and were shipped from Mobile, Alabama to the Minerals Management Service's OHMSETT facility for additional tests including first loss, gross loss, tow speed, oil loss rate, and critical tow speed. The four booms showed thesame trend in response to various wave conditions; the long sinusoidal waves improved containment performance and the short choppy waves degraded performance. One of the four booms achieved slightly higher first and gross oil loss rate tests. One boom demonstrated superior stability at high tow speeds. The results of this test report are consistent with the evaluation of fire booms that had been previously tested at OHMSETT, but also show a slight increase in performance. The tests indicate that the existing fire booms can contain oil in currents up to 1 knot and in various wave conditions after being exposed to multiple burns. This information will be used by the Coast Guard to develop policies and procedures for the in situ burning (ISB) of oil during a spill. [ABSTRACT FROM AUTHOR]

An experimental technique has been developed to study systematicallythe ignition, flame spread and mass loading characteristics of liquid fuels spilled on a water bed. The final objective of this work is to provide a tool that will serve to assess a fuel's ease of ignition,spread and sustaining a flame, thus, helping to better define the combustion parameters that affect in situ burning of oil spills. [ABSTRACT FROM AUTHOR]