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Cold Region Bioremediation of Hydrocarbon Contaminated Soils: Do We Know Enough? Roseanne McDonald† and Oliver G. G. Knox*,‡,§ †
School of Geosciences, Edinburgh University, Edinburgh EH9 3JN, United Kingdom School of Environmental and Rural Sciences, University of New England, Armidale, New South Wales, Australia 2351 sources and causing environmental impacts. Hydrocarbon contamination in these ecosystems is perceived as damaging as they are more sensitive, being profoundly adapted to extreme conditions.1 Ecosystem recovery is slower than in temperate climates and hydrocarbon concentrations can persist for years as natural attenuation rates are slow.2 Increasing this rate of attenuation therefore becomes a serious consideration, but strategies developed for temperate climates are often unsuitable for remote Polar regions as they frequently require equipment and materials that are limited or prohibited.1,3 In the Arctic, remediation is therefore driven by cost and time limitations, regulated through domestic legislation and guidelines, while in Antarctica drivers are cost, environmental policy, and remediation constraints.4 Natural attenuation is not always suitable due to slow rates,1,2 while thermal incineration, common in temperate remediation, is banned from Antarctica and unfavorable in the Arctic due to risk of heat degradation of permafrost and downward contaminant migration.2,4 Excavation and removal of contaminated soils is often impractical, due to costs and risks of further damage from excavation, but might be considered with bioremediation when cost and time are balanced with risk and regulatory pressures.2 umankind is currently reliant on oil and fossil fuels for Bioremediation facilitates remediation activities being underthe majority of its energy requirements. Currently, crude taken either near or on site, which can be appealing in a remote oil extraction from the Polar Regions of the globe is in decline, location, but effectiveness depends on overcoming limitations as the required technology and the associated costs make the in temperature, bioavailability, oxygen, electron acceptors, economics unfavorable. However, political instability and toxicity, and freeze−thaw processes.1,3 Temperature is the security issues, associated with some of the current major oil significant limiting factor, playing a major role in rate and and gas production areas, as well as technological improvedegree of microbial hydrocarbon biodegradation and affecting ments may make oil extraction from the Polar Regions the volatilisation and viscosity of hydrocarbons.3 Strategies to increase temperatures are therefore clearly advantageous for soil favorable. Against this background there is the constant threat bioremediation in polar sites. This can be achieved by that wherever there is oil extraction there is associated landfarming, which also offers control of water, nutrients, contamination and at present humankind’s ability to deal soil−microbe contact, and aeration with minimal equipment with oil contamination in cold environments is restricted. In requirement.4 However, landfarming is often ineffective at order to preserve what remains of these environments we remediating crude oil and moisture management can remain a therefore need to reconsider, adapt and improve our challenge in areas of either high precipitation or Polar desert. approaches to remediation in these cold environments. Biopile systems can also increase temperature, use less area The need for remediation preparedness comes from the fact than landfarming and are becoming increasingly implemented that globally extraction of oil has resulted in the environment in the Arctic, but additional engineering adds to build and being exposed to approximately 25 000 tonnes of crude oil operation costs. Additional or alternative considerations might every year as a result of damaged crude oil pipelines and vessel include bioaugmentation or phytoremediation. Bioaugmentaspills. This figure does not include the 2010 Deepwater tion is uncommon in the Arctic due to a lack of adaptation of incident, which exposed the environment to over half a million the introduced organisms and not permitted in the Antarctic tonnes of crude oil in a single event. Most of these spills and with nonindigenous species. Phytoremediation offers potenpollution events have occurred in temperate environments tially inexpensive remediation for cold sites, but finding plant where remediation technology can be effectively applied, but cold regions pose unique challenges. In Arctic and Antarctic environments, contaminants typically become mobile over only Received: July 28, 2014 Published: August 13, 2014 a couple of summer months, dispersing from their immediate ‡
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© 2014 American Chemical Society
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dx.doi.org/10.1021/es5036738 | Environ. Sci. Technol. 2014, 48, 9980−9981
Environmental Science & Technology
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(4) Filler, D. M.; Reynolds, C. M.; Snape, I.; Daugulis, A. J.; Barnes, D. L.; Williams, P. J. Advances in engineered remediation for use in the Arctic and Antarctica. Polar Rec. 2006, 42 (02), 111−120.
species that accomplish sufficient soil decontamination in cold environments with little management poses a challenge. Native species are expected to be more reliable, but success is dependent on soil temperature, root exploration, water, nutrients, growing season, and soil chemistry. Despite recent growth in bioremediation application in cold regions, agreement is still limited as to which strategy is most effective under Polar conditions. Although ex-situ bioremediation has limitations, it is often the strategy of choice for remediation in cold regions, offering some control over the limiting environmental conditions on microbial activity. Increased human presence, associated with military activities, shipping, “last chance” tourism, scientific research and natural resource exploration has already led to contamination of the Arctic and Antarctic landscapes.2−4 Alaska, Canada, and Russia have all seen an increase in hydrocarbon pollution since the turn of the century.1,3 At present OPEC does not envisage a significant contribution from Artic oil over the next 20 years, but exploration of the regions is growing. In 2008, the U.S. acquired $2.7 billion in bids for the Chukchi offshore lease, while in April of 2014 Russia shipped 70 000 tonnes from the Prirazlomnoye platform. The exploration and exploitation of the Polar Regions as a source of crude oil and gas thus seems likely despite the associated environmental controversy that it presents. Greenpeace recently launched a petition to break the relationship between Shell and toy manufacturer Lego over Shell’s exploration of the Arctic, suggesting the motivation should be to ‘protect this magical place for future generations’. Throughout humankind’s relationship with oil there is an association between extraction and contamination, so if protection of what remains of these cold fragile ecosystems is to be achievable then the quest for more appropriate and applicable remediation technologies is needed now more than ever.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Present Address §
School of Environmental and Rural Sciences, University of New England, New South Wales, Australia 2351. Author Contributions
The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Both authors contributed equally. Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Yang, S.-Z.; Jin, H.-J.; Wei, Z.; He, R.-X.; Ji, Y.-J.; Li, X.-M.; Yu, S.-P. Bioremediation of oil spills in cold environments: A review. Pedosphere 2009, 19 (3), 371−381. (2) Snape, I., Acomb, L., Barnes, D. L., Bainbridge, S., Eno, R., Filler, D. L., Plato, N., Poland, J. S., Raymond, T. C., Rayner, J. L., Riddle, M. J., Rike, A. G., Rutter, A., Schafer, A. N., Siciliano, S. D., Walworth, J. L.,, Contamination, regulation and remediation: An introduction to bioremediation of petroleum hydrocarbons in cold region. In Bioremediation of Petroleum Hydrocarbons in Cold Regions, Filler, D. M., Snape, I., Barnes, D. L., Ed.; Cambridge University Press: New York, 2008; pp 1−37. (3) Delille, D.; Coulon, F. Comparative mesocosm study of biostimulation efficiency in two different oil-amended sub-antarctic soils. Microb. Ecol. 2008, 56 (2), 243−52. 9981
dx.doi.org/10.1021/es5036738 | Environ. Sci. Technol. 2014, 48, 9980−9981
