SGER: Study of the Natural Attenuation of Contaminants Derived from a January 2003 Helicopter Fluids Spill at Lake Fryxell (McMurdo Dry Valleys), a LTER Research Site

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Taylor Valley in the McMurdo Dry Valleys of East Antarctica is the site of a long-term ecological research (LTER) project. The pristine Taylor Valley has three major closed basin perennially ice-covered lakes (Hoare, Fryxell and Bonney). On January 17th 2003, a Bell 212 helicopter crashed on the 5 m thick ice cover of Lake Fryxell, resulting in the spill of ~730 liters of diesel fuel as well as small amounts of synthetic lubricants and hydraulic fluids. An immediate response from personnel based at McMurdo Station allowed initiation of clean up efforts within four days of the crash. However, at least half of the spilled fluids could not be recovered owing to the condition of the ice and the unavoidable close of the field season in early February, precluding further access to the lake site. These fluids will remain trapped in the ice until the next spring (Dec 2003) melt season starts. The site will become accessible in November 2003 when ice cores and water samples can be collected for detailed analyses. Members of the McMurdo Dry Valleys LTER research team have submitted three SGER proposals (0346316, 0346272 and 0347219) to better document the fate and transport of hydrocarbons within the lake ice and water. The goals of the coordinated research effort are to understand the physical, chemical and biological changes that have occurred since the spill and what, if any, the longer-term impact of the spill will be. Results will also provide important information for the improvement of accident response policies in the Dry Valleys.This component of the project will document the natural attenuation of helicopter fluids in the lake ice and has two major objectives: 1) Assess the level of disturbance of the lake ecosystem by evaluating changes in lipid constituents of Lake Fryxell ice caused by this crash. Lipids analyzed in pre-accident lake water and surface sediments will be compared to the contaminant source (jet fuel, lubrication oil and transmission fluids) as well as post-accident ice-cover samples, lake water samples and surface sediments over a two-year period. 2) Determine the level of natural attenuation (evaporation and biodegradation) of the spilled fluids in the frozen lake ice cover will be quantified and evaluate the effect of biodegradation on spilled fluid composition in the ice cover. Graduate students will participate in this research.