Aarhus University Seal / Aarhus Universitets segl

No. 221: Oil spill response in Greenland: Net Environmental Benefit Analysis, NEBA, and environmental monitoring

Wegeberg, S., Frit-Rasmussen, J. & Boertmann, D. 2017. Oil spill response in Greenland: Net Environmental Benefit Analysis, NEBA, and environmental monitoring. Aarhus University, DCE – Danish Centre for Environment and Energy, 92 pp. Scientific Report from DCE – Danish Centre for Environment and Energy No. 221 http://dce2.au.dk/pub/SR221.pdf 

Summary 

This review describes the state-of-the-art techniques for combating marine oil spills:

  • mechanical recovery,
  • chemical dispersants and
  • in situ burning,

and their applicability in the Arctic (Part I). The derived environmental effects from the techniques are described in Part II.

Mechanical containment and recovery are the primary method and first choice in all the Arctic countries and use of pre-approved chemical dispersants is the secondary method. For the US, Iceland and Greenland, however, the use of chemical dispersant requires specific approval and authorization prior to use. In situ burning is only considered used in the US, Canada, Russia and Greenland upon approval.

The fate of an oil spill at sea depends on e.g. the physical/chemical properties of the oil, the ambient conditions and the release conditions. At sea, a number of weathering processes will change the properties and thereby the fate of the oil that will also change the window of‐opportunity for the different oil spill response techniques. Of these weathering processes particular evaporation and emulsification are in focus.

Oil spill response in the Arctic differs from oil spill response in other regions, particularly due to the ice-affected conditions. Other challenges that should be dealt with are limited infrastructure due to remote locations and hence the need for a wider action time-window, harsh weather conditions, winter darkness, and low temperatures. Thus, the oil spill response methods should be adapted to these conditions to achieve the most efficient and robust response to an oil spill with an overall environmental benefit.

The selection of chemical dispersion and/or in situ burning as part of an acute oil spill response strategy must hence add to the overall benefit for the environment, where potential adverse environmental effects of the response techniques are less than the environmental benefit from the operation. This includes a balance between presence and sensitivity of organisms in the oil slick trajectory, in the water column and on the sea surface as well as the expected richness and sensitivity of the shoreline to beaching oil.

To support this choice of the optimal response technique, a Net Environmental Benefit Analysis, NEBA, shall be performed. The NEBA includes the environmental benefits and drawbacks/consequences of burning the oil on the sea surface and/or chemically dispersing the oil slick into the water column as supplements/substitutes to mechanical recovery if the operational or logistical conditions are suboptimal or inhibiting for this response technology.

When the response strategy has been decided and approved by the authorities, the fate and effect of the oil spill/response methods should be followed (Part III). This includes monitoring at spill location, monitoring in the trajectory and the spreading/dispersion of the oil slick and analysis of the oil itself to identify changes in the physical and chemical properties due to weathering (e.g. evaporation, degradation) of the oil.

Oil spill and countermeasures may have effect in air, water, ice, sediments and on coastlines. A sampling programme therefore has to include all these environmental compartments as well as associated biota. The monitoring should also include analyses for toxic effects as well as accumulation of oil components in biota and an integrated approach is recommended. Integrated monitoring hence involves a combination of chemical and biological measurements in water, sediment and biota and includes: the spread and fate of the oil; the efficiency of the oil spill countermeasures; the environmental impacts of the oil spill; potential side effects of countermeasures; and long-term environmental impacts.

Marine oil spills will often result in the stranding of dead and alive seabirds and marine mammals. Under severe conditions very high numbers ‒ tens of thousands of individuals, mainly seabirds ‒ may be affected if close to an oil spill. The term ‘wildlife response’ is used to describe the actions taken to prevent animals from exposure to oil, and when wildlife has been exposed also to collect, kill and/or rehabilitate oiled wildlife (Part IV). The target groups are usually seabirds, marine mammals and in tropical and subtropical areas also turtles, crocodiles and other reptilia, however, in a Greenland context, only seabirds and marine mammals are relevant.

In a Greenland context, the most realistic wildlife response will be euthanasia supplemented with collecting, registration and biological examination of killed wildlife for the purpose of getting information on mortality and affected populations.