Summary of Report: Spill Response in the Arctic Offshore

Transcription

1 Summary of Report: Spill Response in the Arctic Offshore Prepared for the American Petroleum Institute and the Joint Industry Programme on Oil Spill Recovery in Ice

2 Introduction Oil Spill Response in the Arctic Spill Response in the Arctic Offshore As attention turns to the Arctic as an important source of oil and natural gas, the industry is taking proactive steps to develop modern tools and technology to ensure effective solutions are available to handle a potential spill. The region presents unique challenges and it is important to continue to establish best practices for exploration and production. Responding to an oil spill is challenging under any circumstance, but arctic conditions require additional environmental considerations. This series of fact sheets discusses the challenges posed by handling a spill in arctic conditions and the technologies being developed to respond to such an event. In some cases, techniques have been modified from standard response techniques for marine conditions based on years of research. Others have been recently developed. CHALLENGES OF ARCTIC SPILL RESPONSE Perhaps the most significant challenge posed by an arctic spill is dealing with spilled oil in the presence of ice. Ice can make it more difficult to find a spill, reach it and deploy equipment and personnel to respond. Despite this, there are some conditions where Arctic conditions may assist spill response. For example, ice can act as a natural barrier and prevent oil from spreading. Cooler temperatures and waves dampened by the ice can also slow the breakdown or weathering process of oil. This can increase the window of opportumity for recovery, dispersants and in-situ burning. Fate and Behaviour of Oil in Ice: Generally spills under sea ice move with the ice. In winter, currents under the ice in most arctic areas are insufficient to move spilled oil any significant distance from where it contacts the ice undersurface. Spilled oil can be encapsulated in ice through the winter. Typically, the oil is re-exposed in a fresh state ARCTIC SPILL RESPONSE AT A GLANCE Detection and tracking of oil is essential for determining the location, transport, and behavior of a spill. Arctic spill response capability should be flexible and benefit from the use of as many tools and technologies as possible. The oil and gas industry recognizes the need for ongoing improvements and is committed to advancing arctic spill response technologies. during the spring thaw and then behaves similarly to oil spilled in the open ocean. Key weathering processes in the Arctic include evaporation dispersion dissolution, and biodegradation. Detection and Tracking: Detection and tracking of oil is essential for determining the location, transport, and behavior of a spill. Detecting and confirming where a spill is located, either through remote sensing or direct observation, play a critical role in guiding response efforts. Containment and Recovery: Effective mechanical recovery of spills in open drift ice is possible, using conventional boom and skimmer systems modified for cold weather operations. In more closely packed ice, over-the-side and recently developed selfpropelled skimmers can access isolated trapped pools of oil. Dispersants: Dispersants are an effective tool in responding to Arctic spills in ice. Research confirms that dispersants can minimize the impact of a spill by rapidly lowering hydrocarbon concentrations in the marine environment, minimizing the persistence of surface slicks, reducing or eliminating shoreline oiling, and protecting wildlife. In-Situ Burning: In-situ Burning (ISB) is a safe, efficient, and proven response technique in the Arctic. This method can rapidly eliminate more than 90 percent of spilled oil that is encountered. Compared to other response options, fewer equipment and personnel requirements make ISB a more practical response method in Arctic environments. Protecting and Cleaning the Shore: Established methods for shoreline protection and cleaning are generally applicable in the Arctic with modifications to cope with unique conditions such as ice rich tundra cliffs. Challenges include supporting personnel in remote locations, establishing approved disposal sites for oily debris and the short summer season. CONTINUING RESEARCH The oil and gas industry recognizes the ongoing need to build on existing research and improve the technologies and methodologies for Arctic spill response. There are currently seven key areas of research managed by the International Oil and Gas Producers Association, Joint Industry Programme: Dispersants, Environmental Effects, Trajectory Modeling, Remote Sensing, Mechanical Recovery, In- Situ Burning and Field Research. ABOUT In January 2012, members of the international oil and gas industry launched a collaborative effort to enhance arctic oil spill capabilities. This collaboration, called the Arctic Oil Spill Response Technology Joint Industry Programme (JIP), will expand industry knowledge of, and proficiencies in Arctic oil spill response. This series of fact sheets is derived from the OGP/IPIECA report Spill Response in the Arctic Offshore published in February To read the full report, visit: Files/EHS/Clean_Water/ Oil_Spill_Prevention/Spill- Response-in-the-Arctic- Offshore.ashx Vessel supporting research in the Arctic. Photo: JIP Oil in Ice, Scientists measure acoustic properties of ice in an effort to detect trapped oil at Svalbard, Norway. Photo: D. Dickins,

3 Fate and Behaviour of Oil in Arctic Conditions When responding to a spill in the Arctic, it is critical to understand how the oil will behave in these unique conditions. Spill response in this region requires extensive environmental knowledge and poses challenges and opportunities that must be taken into consideration. MOVEMENT OF OIL The spreading of oil on ice is similar to the spreading of oil on land. The rate of spread is controlled mainly by oil viscosity, so cold temperatures tend to slow spreading. Oil spilled on rough ice surfaces may be contained in a thick pool bounded by natural ridges and blocks on the ice surface. As a result, slicks on ice tend to be much thicker and smaller than equivalent slicks on water. Additionally, snow will absorb spilled oil, further reducing its spread of oil. Even large spills of crude oil beneath solid or continuous ice cover will usually be confined within relatively short distances from the spill source. Generally, spills on sea ice will move with the ice. If the ice drifts, oil drifts with it. In winter, currents under the ice in most arctic areas are insufficient to move spilled oil any significant distance from where it contacts the ice undersurface. BEHAVIOUR OF OIL IN ARCTIC CONDITIONS AT A GLANCE Ice, snow and cold temperatures can greatly reduce spread of spilled oil. Oil biodegrades in all marine environments, including icefilled waters. Oil trapped within ice in the winter typically emerges at the surface during spring thaw. Encapsulated oil released due to spring thaws acts similarly to oil spilled in open water. SEASONAL CHANGES Seasonal changes and ice formation can significantly impact the behaviour of oil in arctic waters. First-year, growing sea ice will completely encapsulate oil released beneath it. This process takes a few hours to a few days, depending on time of year. However, after oil is encapsulated, it remains trapped until the spring thaw, when oil migrates through melt channels to the ice surface. Once oil reaches the ice surface, it floats on melt pools or remains in patches on the melting ice surface. Oil spilled under older ice will remain in place as it would under first-year ice. Oil spilled under multi-year ice may appear on melt pools at the surface, but likely much later in the melt season than for first-year ice. When ice sheets thaw and break up, oil remaining in melt pools on the surface will flow into water in a thin sheen trailing from the drifting ice. Once exposed to significant wave action, fluid oil mixed with water and may naturally disperse. Viscous oils that have gelled in the cold may be discharged as thicker, nonspreading mats or droplets. Gelled oil forms are more resistant to mixing and dispersion and require a different response tactic. TEMPERATURE S ROLE Temperatures can significantly impact the natural weathering processes of oil. Evaporation typically plays a significant role in the natural weathering of spilled oil and oil products. Following discharge, most crude oils and light products such as diesel and gasoline experience significant evaporation relative to heavier, more viscous oils, including bunker fuel and emulsified oils. In spite of slower rates, given sufficient time, evaporation is still an important process in significantly reducing the spill volume for oil on the water or ice surface under arctic conditions. Dissolution is a relatively minor weathering process (few per cent by volume) where the light ends of fresh oil can dissolve into sea water. Oil is naturally dispersed into the water column where wind and waves are strong enough to break an oil slick into micron-sized droplets that disperse and dilute in the water column. The extent to which dispersion occurs depends on the oil type and the amount of mixing energy provided by the wind and waves. This process is less prevalent in the Arctic due to the presence of ice which can reduce or block waves. Dispersed oil readily degrades in marine environments. Studies have shown that naturally occurring oil-degrading microbes begin to grow on dispersed oil droplets in a few days. Microbial communities in the Arctic waters have adapted to the low temperatures of their environment and rapidly adapt to and consume dispersed oil. Researching the behaviour of oil in ice. Photo: JIP Oil in Ice, Figure 1 Scenarios demonstrating the behaviour of oil spilled in arctic fast ice. Figure: A.A. Allen ABSORB Oil Spill Contingency Plan,

4 Detection, Monitoring and Tracking of Spilled Oil in Artic Conditions Airborne Remote Sensing: Multispectral airborne remote sensing supplemented by visual observations by trained observers remains the most effective method for identifying and mapping the presence of oil on water. Modern pollution surveillance aircraft operated by nations such as Canada and Sweden employ a mix of sensors such as Side Looking Airborne Radar, and Forward Looking Infrared together with conventional digital cameras. Visible sensors are constrained by darkness, fog and cloud cover. EMERGING TECHNOLOGIES New technologies being developed through laboratory and tank testing could improve our ability to detect and map oil trapped under ice in the near future. Examples include Frequency Modulated Continuous Wave (FMCW) airborne radar, Nuclear Magnetic Resonance (NMR) and upward looking sonar mounted on autonomous underwater vehicles. Unmanned Air Systems (Drones) could provide long-endurance aerial surveillance over a spill site. High-resolution satellite imagery; The national ice services of a coalition of countries including Canada, Russia, United States, Denmark and Norway; Oceanographic and meteorological services; Surveillance aircraft; Commercially available satellite tracking beacons; and Environmental monitoring and tracking buoy data. Satellite Radar Systems: The advent of Synthetic Aperture Radar (SAR) satellites in the 1990 s represented a quantum leap in our ability to monitor arctic sea ice under all weather conditions and through periods of winter darkness. SAR has proven effective in mapping large oil slicks on the open ocean and could be effective in open ice conditions. Ground-Penetrating Radar (GPR): TRACKING AND MODELLING SPILLED OIL IN ICE Predicting the future position of spilled oil provides information that can be used to direct both airborne and marine resources, a crucial tactic in containing potential spills. Sources of tracking information include: Test and Evaluation of Ground Penetrating Radar at Svalbard Norway. Photo: D. Dickins, Environmental data monitoring and tracking buoy. Photo: JIP Oil in Ice, In the case of a spill, the detection, monitoring, and tracking of oil in arctic conditions is critical in determining what resources are required to quickly mitigate impact. Spill response must include flexibility and access to all available tools and strategies to stop the discharge, contain the spill and remove or recover the oil from the environment. Detection, monitoring and tracking are activities that depend on an integrated feedback loop using realtime data provided from many different sources, for example satellite imagery, airborne sensors, underwater vehicles and forecast modelers. DETECTING OIL Years of research on detection, monitoring and tracking technologies clearly indicate that no single sensor system, on its own, meets the needs of predicting the movement of oil in the Arctic environment. A flexible response strategy combining airborne, satellite, surface and sub-surface-based technologies provides the best data for accurately directing the activities of an oil spill response. The following technologies are in use today: DETECTION, MONITORING AND TRACKING AT A GLANCE Detection and tracking of oil is essential for determining the location, transport, and behavior of a spill. Arctic spill response capability should be flexible and benefit from the use of as many tools and technologies as possible. The oil and gas industry recognizes the need for ongoing improvements in this field and is committed to advancing arctic spill response technologies GPR has been successfully used to detect oil under ice and within ice. Readily available, commercial GPR systems can also be deployed and used to detect crude oil spills under snow cover. GPR is currently being developed for aerial deployment, but this is not yet an operational tool. Integrated Systems: Integrated shipboard systems can utilize a combination of high speed marine radar, long range thermal imaging cameras (FLIR), low light video and GPS tracking buoys. Integrated airborne systems fuse data from a mix of sensors into a series of products that display different aspects of the spill to responders, for example differentiating between thick and thin areas. Trained Dogs: Dogs can be used to detect oil spills covered with snow and ice. Tests in Norway with trained dogs carrying GPS transmitters have found they can determine the bearing of an oil spill at a distance of 5km. 6 7

5 Containment and Recovery of Oil Mechanical containment and recovery is considered the primary or preferred response strategy in many regions of the world. Containment booms are normally used in combination with a skimmer to remove oil from the water s surface where it is temporarily stored before being processed and disposed of. Environmental and oceanographic conditions and spilled oil s physical properties are used to determine the type of mechanical equipment best suited for oil recovery. Oil spreads less and remains concentrated in greater thicknesses in broken ice compared to open water. Most mechanical recovery systems are technologies developed for open water; however, several types of skimmers have been developed specifically for recovering oil in ice. Depending on the time of year, responders can be facing a spill in open water and with varying amounts of ice cover. Mechanical Recovery of Oil In Open Water Oil spilled on open water will quickly spread to form a thin slick. As a result, some form of containment is generally required for effective recovery and removal. This is typically done with an oil containment boom towed at low speed by vessels, a technique that becomes less effective as time passes and the slick continues to spread. Once oil is contained and concentrated to a thicker slick, various oil recovery devices can be used to remove it from the water surface. There are currently four main types of skimmers used for this purpose: Containment and Recovery At a Glance Several types of skimmers have been developed specifically for recovering oil in ice-covered regions. These skimmers are often brush belts or drums rotating through the slick and capable of recovering oil while processing small ice pieces. Some skimming units are equipped with heating systems, ice deflection frames, and advanced systems for pumping viscous oil/water/ice mixtures. Containment booms, ice, and snow provide barriers against the spread of oil and result in a thicker layer of oil available for recovery. Environmental and oceanographic conditions and the oil s physical properties should be taken into account when determining what type of mechanical recovery instrument is best suited for oil recovery in the Arctic. Oleophilic Systems: In oleophilic skimming systems, oil adheres to a drum, belt, brush, disc or mop that is rotated at the water s surface. The oil is then scraped off into a storage chamber or reservoir. These devices are efficient and it is common for them to result in a high recovered oil-to-water ratio. Light to medium-viscosity oils are most suited to these systems though very high viscosity oils can be handled using certain fittings. Weir Skimmers: A weir skimmer collects liquid at the surface of the water. Round floats hold a collection bucket at a level that allows oil to slip over the edge and into a collector. These units are less efficient than oleophilic skimmers and collect a significant amount of water with the oil, requiring additional storage capacity. A benefit of weir skimmers, however, is their ability to handle both light and heavier oil products. Vacuum Skimmers: These skimmers use vacuum to lift oil from the surface of the water or the shore. Vacuum systems are versatile and can be used on a variety of oil types, with the exception of heavy oil and volatile products. A disadvantage is that they can be inefficient, recovering more water than oil. Mechanical Skimmers: These systems physically lift oil from the surface and include various mechanisms from conveyor belts to grab buckets to contain it. These types of skimmers are more suited to very viscous oils. Storing and separating An important factor for an effective containment and recovery operation is the availability of storage on a skimming vessel. The storage volume relative to the recovery capability of the skimming system being used is critical. For example, weir skimmers are prone to collecting large volumes of water relative to oil and can rapidly fill storage containers, barges, and tanks. The nature of the recovered product plays an important role in determining transfer and storage requirements. Heavy oils can be difficult to handle, particularly in cold temperatures. Specialized pumps may be required and storage tanks may require heating coils to allow the recovered product to be removed. The separation of water from recovered oil, also known as decanting, into a temporary storage system for retreatment is important to extending the operating capability of individual skimming systems. Mechanical recovery of oil in ice In open water booms are usually required to contain and thicken spills for mechanical recovery. A conventional booming strategy is most effective in open water with ice concentrations below 30 percent. Any mechanical recovery system working in ice-covered waters needs to deflect the ice in order to gain access to the oil and effectively remove it. Single vessels with built-in skimming or over-the-side-skimming systems using short sections of boom can maneuver between large ice floes and operate in higher ice concentrations than vessels towing independent booms. As ice concentrations increase beyond 60 percent, ice can provide a natural barrier against the spread of oil. This natural containment can provide an advantage for recovery operations in responding to small spills, using skimmers deployed directly from the side of a vessel. Several types of skimmers have been developed specifically to recover oil in ice-filled water. Desmi Polar Bear Ice Skimmer. Photo: SINTEF, M/V Nanuq, a 301-foot arctic A-1 Class Oil Recovery Platform Service Vessel. Photo: U.S. Coast Guard,

6 Chemical and Mineral Dispersion of Spilled Oil low toxicity to marine life and they are rapidly diluted; Dispersants do not increase the toxicity of oil; Arctic organisms are no more sensitive to dispersed oil than temperate organisms; Dispersed oil can cause temporary impacts to sensitive marine species but these are limited to the immediate spill vicinity and for a short period of time; and, Rapid dilution and biodegradation limit impact to the ecosystem from both dispersants and dispersed oil. Dispersion of oil using either chemical or mineral additives can be an effective way to enhance the natural biodegradation process for removing oil from the environment in the case of a spill. Research has shown that dispersants are an effective solution in arctic environments. Oil is naturally dispersed in water when waves and wind are strong enough to break an oil slick into tiny droplets that mix into the water below. The extent to which this dispersion occurs depends on the type of oil and the amount of mixing energy provided by wind and waves. Chemical and mineral products, called dispersants, can enhance this natural process to help reduce the effects of spills. The decision to use dispersants for oil spill response is determined through a Net Environmental Benefit Analysis (NEBA). A NEBA helps decision-makers determine which response strategy for example mechanical recovery, dispersants, or in-situ burning [ISB] will minimize environmental harm. The NEBA process is important in an arctic environment, and it is a critical aspect of any contingency plan. The basics of Dispersants Dispersants are a mixture of chemicals, similar to common dish soap, that quickly dilute and biodegrade in water. Dispersants are most effective when applied to fresh oil but can work well on weathered oil depending on the oil type and ambient conditions. They are typically applied using boat, plane or helicopter spray systems or by subsea injection. Dispersants are used to remove oil from the environment by enhancing natural biodegradation. This is achieved by Dispersants At a Glance Oil biodegrades in temperatures found in arctic waters. Arctic organisms are no more sensitive to dispersants or dispersed oil than temperate organisms. In open drift ice conditions, waves may be strong enough to initiate the dispersion of treated oil. In more dense ice conditions, the energy provided by a storm or from the propeller wash of a ship will be adequate. Dispersants can minimize the impacts of an oil spill by: Enhancing removal of oil from the environment through biodegradation; Minimizing the impact of surface slicks on marine mammals and birds; and, Preventing oil from reaching sensitive shorelines. converting an oil slick to micronsized droplets that disperse and dilute in the water. Although dispersants may increase the amount of oil in an area of water in the short term, the rapid dilution of dispersed oil in the water column quickly reduces potential impacts on sealife in the immediate spill area while removal of oil from the surface minimizes the potential harm to marine mammals and birds and prevents oil from reaching the shore. Dispersants have an advantage over other response options not only because they can treat large areas very rapidly, but also because they can be applied over a greater range of wind and wave conditions than other response options. Another advantage of dispersants is they can be remotely applied using aircraft. This increases responder safety by minimizing the need to put personnel on the water surface and also increases the speed of the response compared to boat-based options. Dispersants in Cold Water and Ice: Dispersants have been proven to be effective when applied at freezing and near-freezing temperatures where spilled oil has not gelled. Water partially covered with ice can increase the time a dispersant is effective by up to one week, as ice can prevent oil from becoming weathered and emulsified. Research has also shown that ice can enhance dispersion, since ice motion can increase the surface turbulence, or mixing energy, needed for the process. Further, in marine situations where there are inadequate waves, the propeller wash from a ship can be used to enhance the necessary mixing energy. Dispersants in Brackish Water: Marine dispersants are most effective in salt water. However, fresh and brackish water dispersants have also been developed. The most effective dispersant will have to be determined during oil spill contingency planning, considering the conditions for specific spill scenarios. Dispersed Oil in Arctic Habitats: Dispersed oil readily biodegrades in marine environments, all of which contain petroleum degrading bacteria. Laboratory studies have shown that naturally occurring oil-degrading microbes begin to grow on dispersed oil droplets within a few days. The microbial communities in arctic waters have adapted to the low temperatures of their environment and rapidly adapt to and consume dispersed oil, removing the spilled oil from the environment. Modern dispersants are made of low toxicity, biodegradable components and ingredients found in many household products. Research indicates that: Dispersants themselves are of Ongoing research A recent study has shown that natural mineral fines combine with oil slicks or oil on shorelines to disperse oil in water by forming Oil-Mineral Aggregates (OMA). OMAs increase the rate of natural biodegradation, similar to chemically dispersed oil droplets. Studies indicate that the use of minerals combined with the wash of a ship s propeller speeds up the rate of biodegradation even further. Crew of Basler BT-67 fixed wing aircraft releases dispersant over an oil slick from the Deepwater Horizon, off the shore of Louisiana on May 5, Photo: U.S. Coast Guard by Petty Officer 3rd Class Stephen Lehmann, Chemical Dispersion Process. Photo: ExxonMobil

7 Controlled Burning of Spilled Oil Controlled, in-situ burning is a response option that has proven safe and effective for removing oil in the case of an oil spill. As attention turns to oil and gas exploration in the Arctic, research continues to advance the use of this technique in the region. In-situ burning (ISB) is a process that transforms oil into its primary combustion products of water and carbon dioxide. The method has been used as an effective tool in the removal of oil since ISB is less labour intensive than other recovery techniques and requires minimal equipment. It has the advantage of being more versatile in its application, as it can be applied in regions where there is a lack of infrastructure or where habitats are particularly sensitive. Since ISB removes oil from land or water surfaces, the need for physical collection, storage, and transport of recovered oil is also greatly reduced. The Arctic environment helps with the efficiency of ISB as the presence of ice reduces the spread of spilled oil and reduces the size of waves. These conditions yield thicker oil slicks, which increases the effectiveness of ISB as a solution, while the cooler temperatures slow evaporation and extend the window of opportunity to conduct ISB activity. THE BASICS OF IN-SITU BURNING In order for ISB to be effective, three elements must be present: fuel, oxygen, and a source of ignition. The following conditions need to be considered for ISB to be a practical option: Slick Thickness: Depending on the fuel type and its evaporation rate, the minimum oil thickness for ISB ranges from one millimeter to 10mm. Wind Speed: ISB is most effective in low to moderate wind conditions so air above a slick retains an ignitable concentration of vapour. The maximum wind speed for successful ignition is about metres per second (20-25 knots). In greater wind speeds, vapour concentrations decline and cannot sustain a burn. Wave Height: When used on a water surface, ISB is most effective in low to moderate wave conditions. The maximum wave height for effective ISB is about 1.2 metres (4 feet). Fire resistant booms can withstand some wave activity, but at higher wave heights its effectiveness declines. Sea ice can be effective in containing oil by acting as a natural barrier while also reducing wave activity. Emulsions: Water may mix with spilled oil and form a foamy, pudding-like emulsion, often called mousse. For most oils, 25 percent water IN-SITU BURNING AT A GLANCE ISB is a safe, efficient, and proven response technique that can rapidly eliminate more than 90 percent of encountered oil. The presence of colder temperatures and calmer conditions may increase the window of opportunity for the effective use of ISB. Different oil-in-ice concentrations will influence the efficiency of ISB. ISB emissions are short lived and not likely to cause significant environmental effects or human health issues. Safety regulations and air quality monitoring requirements are in place for ISB to ensure the ongoing safety of its use. Compared to other response methods, fewer equipment and personnel requirements make ISB a more practical response method in arctic environments. is viewed as an upper limit for emulsions that can be burned. However, there are some crude oils that can be easily ignited with a higher percentage of water. Igniters: A variety of igniters are available to deploy from surface (land and vessel) and aerial platforms to ignite an oil slick. They include simple devices such as flares, propane torches, and plastic bags of gelled fuel. Other devices have been designed or modified for ISB, such as the helitorch and ejectable igniters. Fire-Resistant Containment Booms: Several types of fire-resistant booms have been developed. Some are constructed of steel and some are water-cooled, while others are constructed of heat resistant fabric. IN-SITU BURNING UNDER VARIOUS CONDITIONS On Open Water: The practice of intentional burning of oils slicks on open water has been in place since the early 1980s, when fire-resistant booms were first developed. The use of fire-resistant booms to conduct ISB is often more efficient than other response methods and requires fewer resources than traditional booming and skimming. In Broken Ice: ISB has proven effective in drifting offshore pack ice conditions, but effectiveness varies based on ice conditions. In open water, fireresistant booms can be towed by vessels to thicken slicks for burning. In a case where oil is spread across an area where there is 40 to 60 percent ice cover, sea ice will reduce slick spreading, but cannot completely constrain it. The deployment of booms and towing vessels is risky and there is an increased likelihood of boom failure due to interference by ice. Greater ice concentrations can serve as a natural boom to effectively contain a slick. The primary concern in these conditions is how to reach the slick to ignite it. On Solid Ice: ISB is the method of choice when removing oil pools on ice, whether on land or at sea. Based on field studies, ISB can remove on average between 60 to 70 percent of spilled oil on a solid surface. In Snow: Oil that is mixed with snow can be successfully burned when pushed Image: In-Situ Burning of Oil Process. Photo: SL Ross. into cone-shaped piles. When a limited amount of oil is found in snow, a fire starter, such as diesel fuel or gelled gasoline, may be necessary to start a burn. Snow mixed with as little as three to four percent oil can be burned, removing up to 90 percent of the oil even two weeks after a spill. EMISSIONS FROM IN-SITU BURNING Burning oil produces a smoke plume of particulates and gases. Combustion of crude oil is estimated to produce 75 percent carbon dioxide and 12 percent water. The remaining smoke constituents are from oil, which is converted to carbon monoxide and soot. Real-time monitoring of the burn plume is important to ensuring smoke concentrations do not exceed air quality standards so as to avoid any impact to human (or animal) health. Residue from incomplete combustion will remain. When on land such residues can be collected. Should they sink in a water column before recovery, they may affect bottom dwelling plants and animals by localized smothering. Sunken residue concentrations are likely to be sparse and/or small in extent. Knowing the oil properties, it is possible to predict whether residue sinking is a concern

8 Shoreline Protection and Recovery In the event of an oil spill, it is vital to protect the Arctic shoreline from contamination whenever possible. The industry continues to develop best practices and technologies that enhance the ability to protect sensitive shorelines. To a large extent, the shorelines of the Arctic are similar to those of ice- and snow-free environments. Some specific shore types are unique to the Arctic though, including: Tundra and tundra cliffs; Boulder barricades and sediment ridges created by rafting or ice pressure; and, Ridges and scarred shores on coasts with fine-grained sediments (sands, silts and clays) located in sheltered bays. Shoreline protection protocols Many arctic regions have welldefined human and animal habitats that can be easily identified and mapped. Setting response priorities involves communication with regional and local communities to identify important sites as well as areas of economic and recreational value. The primary response strategy in all oil spills is to contain, recover or eliminate oil on water as close to the source as possible. If oil cannot be prevented from reaching the shore, the key priority is to minimize impacts to the shoreline environment. In Arctic or other cold climate habitats, the timing of response operations will vary based on the season and the presence of ice and snow. Effects of Ice on Oil: When ice is present in the shore zone prior to offshore winter freeze, it can protect the shoreline from approaching oil by forming a natural, impermeable barrier. The presence of shore ice can also modify the behaviour of oil spilled close to the shoreline in the following ways: Oil spilled into ice cracks may be carried or trapped under the floating ice through tidal action; Oil stranded after break-up may become mixed among remaining grounded floes, coating the floes and shoreline; Oil moving onshore after freezeup along the coast can become incorporated within the expanding ice zone or covered by newly formed ice at the advancing ice edge; and, The penetration of oil deposited on a beach that is free of ice in the summer may be limited by the presence of subsurface ice (ice lenses) throughout the year. Effects of Snow on Oil: Typically, fresh snow acts as a sponge for spilled oil, reducing surface spreading. While oil covered by snow will continue to undergo evaporation, it does so at a much lower rate than oil directly exposed to the air. With the arrival of summer, the remaining oil will eventually evaporate at approximately the same rate as it would if spilled on water in summer. Shoreline Protection at a glance Since ice is impermeable, oil remains on the surface of shoreline ice unless new ice is forming. Ice in water can prevent oil from reaching the shore. Pre-planning protection priorities requires communication and collaboration at regional and local levels. Cleaning an oiled arctic shore must account for sensitive environments. Washing or manual removal techniques are labour intensive. Mechanical removal is faster but generates more waste, whereas in-situ treatment minimizes waste. Image: US Coast Guard Pollution Investigator at Cosco Busan oil spill. Photo: U.S. Coast Guard, Detection of Oil in Ice and Snow on the Shore: Shoreline Cleanup Assessment Technique (SCAT) is commonly used as a method to detect and outline the location of oil on shore. SCAT has been adapted for use in cold climates and on shorelines covered in ice or snow. This technique is based on a systematic survey of surface and subsurface oil to create an information base for the response team to use in decisionmaking. Shoreline cleanup Any cleanup decision process must balance environmental concerns, needs of local communities, operational practicality, and safety. The Net Environmental Benefit Analysis (NEBA) process is particularly important in arctic environments where recovery would be expected to be slower and where tundra or wetland shorelines are susceptible to disturbance by human or vehicle traffic. To a large extent, the same strategies and tactics typically used in warmer environments apply to Arctic and cold-climate shorelines. However, the selection of cleanup options depends on the character of the shore zone and the presence of ice and snow. The tactics that can be used to treat or clean shorelines can be grouped into three basic response strategies. Natural Recovery: Allowing shorelines to recover naturally is often the least damaging alternative for light and moderate spills, particularly where access is limited or difficult. This strategy may be appropriate when: Treating or cleaning spilled oil may cause unacceptable levels of environmental damage; Response techniques would not be able to accelerate natural recovery; or, Response personnel would be put in danger. Physical Removal: One tactic for removing oil from shore is flooding and washing stranded oil into adjacent water where it can be contained and collected. Manual removal may also include collecting oil using shovels and rakes, cutting oiled vegetation and using passive sorbents; these strategies are slow and labor intensive and recover moderate amounts of oil. Mechanical removal techniques use equipment designed for earth-moving or construction projects. Although the cleanup rates are less labor intensive and often quicker than manual removal, there is a possibility of significant waste generation that must be addressed by the response team. In-Situ Treatment: These options involve treatments that are conducted on-site and minimize the amount of spilled oil. In-situ treatment is particularly suited for remote areas where logistics are a major factor in operational practicality and safety. Tactics include: Mechanical mixing of oiled sediments through agitation either in the absence of water ( dry mixing) or in water ( wet mixing) to create a sediment-oil mixture that increases weathering and reduces the potential for wildlife impacts; Sediment transfer involving relocating oiled sediments to another location with higher wave energy levels; and, Chemical or biological tactics that involve the addition of agents to facilitate removal of oil or accelerate natural, in-situ oil degradation

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