Measuring ignitability for in situ burning of oil spills weathered under Arctic conditions: from laboratory studies to large-scale field experiments

PAHs in high Arctic copepods Calanus hyperboreus following exposure of residues from in situ burning of oil spill

In situ burning of marine oil spills reduces the total amount of oil in the environment, but a negative side effect may be the generation of environmentally hazardous polycyclic aromatic hydrocarbons (PAHs) that may pose a risk for bioaccumulation, particularly in organisms having a high lipid content. In this study uptake of PAHs from oil and burn residue were examined in the high arctic copepod Calanus hyperboreus. A major part of the low ring number petrogenic PAHs in the oil was removed during burning and relative higher concentrations of pyrogenic high ring number PAHs was found in the burn residue. This suggests that burning markedly reduces the general PAH exposure load. Furthermore, the pyrogenic PAHs generated during the burn were not bioconcentrated to quantifiable levels in the copepods. We conclude that in situ burning can mitigate the potential risk of PAH uptake for copepods and other pelagic organisms in the marine environment as the pyrogenic PAHs only pose low risk for uptake from the water by the copepods and other pelagic organisms.

Heat release rate of enhanced large-scale open oil slick fires with Outdoor Gas Emission Sampling (OGES) system

The Outdoor Gas Emission Sampling (OGES) system was developed to serve as an economical alternative to expensive industrial gas monitoring equipment. By establishing a sampling plane with four discrete sampling points along the radial direction of the smoke plume, the heat release rate (HRR) was measured for large-scale open oil slick fires. This newfound technique was particularly noteworthy during enhanced burns involving Flame Refluxer™ technology, where it is believed that partial premixing of the fuel and air by the apparatus resulted in a higher HRR than existing flame height correlations would suggest, evident by the HRR calculated using mass burning rate and gas analysis methods, which were in good agreement. Results from OGES show the potential of using point sampling within the plume regime to measure the HRR of fires that exceed the capabilities of conventional hood-based calorimeters, especially when it pertains to large-scale open burns.

Chemical herding of weathered crude oils for in-situ burning

Mid-scale ISB experiments were conducted in a large water-basin (20 m² × 1 m) in order to assess the applicability of chemical herding of weathered crude oil spills on water in association with in-situ burning (ISB). A silicone-based chemical herding agent, OP-40, was used to confine, or herd, three different crude oils (Siri, Grane and Oseberg blend) at various weathering degrees. The herding agent was capable of obtaining the minimum required oil slick thickness for ignition and subsequent flame spread in most of the experiments, but not for the strongly weathered oils. Also, the herding agent was capable of re-thickening the oil slick after flame extinction. The burning efficiency results indicate that the method can be viable for ISB with herders at a larger scale, and suggest that the burning efficiency scales with the amount of crude oil. Sinking behaviour of residues was also observed and quantified, as such a behaviour can pose a serious environmental threat in real scenarios.

In-situ burning with chemical herders for Arctic oil spill response: Meta-analysis and review

With increased oil exploration and marine activity in the warming Arctic, there is an increased risk of future oil spills in the Arctic region. In-situ burning (ISB), along with the use of chemical herders (to thicken the slick of spilled oil) has emerged as a potentially viable oil-spill response technique for various Arctic scenarios. The purpose of this research review is to document the field use, research, and analysis regarding the use of ISB to address an offshore oil spill response in the Arctic, with a specific focus on the use of chemical herders to aid ISB in Arctic waters. The compilation of this work involved a systematic review of available experimental data, studies on actual spill-response events, and resulting recommendations on this topic. Both peer-reviewed and available gray literature from the early 1970s through 2018 were evaluated. Selection criteria centered on herders for use with ISBs, Arctic conditions as they relate to ISB, and operational windows of opportunity and environmental risk for this type of oil spill response. From the available literature, more than a hundred articles are referenced herein, and annotated summaries provided. There is general agreement that ISB should be classified as a viable response option for the Arctic offshore to be implemented as part of a multi-layered approach (ASTM 2014; Fritt-Rasmussen et al. 2017; NRC 2014; Rolandsen 2018). In addition, there continue to be gaps noted concerning the availability of monitoring/surveillance personnel and equipment, and logistical/safety considerations for working in the Arctic, as well as specific information on the fate and potential impact of herders and burn residue on Arctic receptors (NRC 2014; Nuka 2016; US-DOI and USGS 2011). This review provides background information for researchers, responders, decision-makers, communities, and is a resource when developing and approving an oil spill response plan or planning future research which includes the use of ISB and herders.

Seasonal ecology in ice-covered Arctic seas - Considerations for spill response decision making

Due to retreating sea ice and predictions of undiscovered oil and gas resources, increased activity in Arctic shelf sea areas associated with shipping and oil and gas exploration is expected. Such activities may accidentally lead to oil spills in partly ice-covered ocean areas, which raises issues related to oil spill response. Net Environmental Benefit Analysis (NEBA) is the process that the response community uses to identify which combination of response strategies minimises the impact to environment and people. The vulnerability of Valued Ecosystem Components (VEC's) to oil pollution depends on their sensitivity to oil and the likelihood that they will be exposed to oil. As such, NEBA requires a good ecological knowledge base on biodiversity, species' distributions in time and space, and timing of ecological events. Biological resources found at interfaces (e.g., air/water, ice/water or water/coastline) are in general vulnerable because that is where oil can accumulate. Here, we summarize recent information about the seasonal, physical and ecological processes in Arctic waters and evaluate the importance these processes when considering in oil spill response decision making through NEBA. In spring-time, many boreal species conduct a lateral migration northwards in response to sea ice retraction and increased production associated with the spring bloom. However, many Arctic species, including fish, seabirds and marine mammals, are present in upper water layers in the Arctic throughout the year, and recent research has demonstrated that bioactivity during the Arctic winter is higher than previously assumed. Information on the seasonal presence/absence of less resilient VEC's such as marine mammals and sea birds in combination with the presence/absence of sea ice seems to be especially crucial to consider in a NEBA. In addition, quantification of the potential impact of different, realistic spill sizes on the energy cascade following the spring bloom at the ice-edge would provide important information for assessing ecosystem effects.

Scale-up considerations for surface collecting agent assisted in-situ burn crude oil spill response experiments in the Arctic: Laboratory to field-scale investigations

In the event of a marine oil spill in the Arctic, government agencies, industry, and the public have a stake in the successful implementation of oil spill response. Because large spills are rare events, oil spill response techniques are often evaluated with laboratory and meso-scale experiments. The experiments must yield scalable information sufficient to understand the operability and effectiveness of a response technique under actual field conditions. Since in-situ burning augmented with surface collecting agents ("herders") is one of the few viable response options in ice infested waters, a series of oil spill response experiments were conducted in Fairbanks, Alaska, in 2014 and 2015 to evaluate the use of herders to assist in-situ burning and the role of experimental scale. This study compares burn efficiency and herder application for three experimental designs for in-situ burning of Alaska North Slope crude oil in cold, fresh waters with ∼10% ice cover. The experiments were conducted in three project-specific constructed venues with varying scales (surface areas of approximately 0.09 square meters, 9 square meters and 8100 square meters). The results from the herder assisted in-situ burn experiments performed at these three different scales showed good experimental scale correlation and no negative impact due to the presence of ice cover on burn efficiency. Experimental conclusions are predominantly associated with application of the herder material and usability for a given experiment scale to make response decisions.

The value of offshore field experiments in oil spill technology development for Norwegian waters

The blowout on the Ekofisk field in the North Sea in 1977 initiated R&D efforts in Norway focusing on improving oil spill contingency in general and more specifically on weathering processes and modeling drift and spreading of oil spills. Since 1978, approximately 40 experimental oil spills have been performed under controlled conditions in open and ice covered waters in Norway. The importance of these experimental oil spills for understanding oil spill behavior, development of oil spill and response models, and response technologies are discussed here. The large progress within oil spill R&D in Norway since the Ekofisk blowout has been possible through a combination of laboratory testing, basin studies, and experimental oil spills. However, it is the authors' recommendation that experimental oil spills still play an important role as a final validation for the extensive R&D presently going on in Norway, e.g. deep-water releases of oil and gas.

Effects of oil and oil burn residues on seabird feathers

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.

Composition of in situ burn residue as a function of weathering conditions

Troll B crude oil was weathered under Arctic conditions with different ice coverage: open water, 50% ice and 90% ice. Samples (100 mL) 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.

A sustainable approach to controlling oil spills

As a result of the huge economic and environmental destruction from oil spills, studies have been directed at improving and deploying natural sorbents which are not only the least expensive but also the safest means of spill control. This research reviews the limitations and environmental impact of existing cleanup methods. It also justifies the need for concerted research effort on oil spill control using natural and sustainable technology concepts. The article proposes future guidelines for the development of a sustainable cleanup technology. Finally, guidelines for the development of a new technology for the Middle East are proposed, which is the use of an abundant resource--date palm fibers--for such techniques.