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

位于东南极麦克默多干旱河谷的泰勒谷是一项长期生态研究(LTER)项目的所在地。原始的泰勒山谷有三个主要的封闭盆地，常年被冰覆盖的湖泊(霍尔、弗莱克塞尔和邦尼)。2003年1月17日，一架贝尔212型直升机在弗莱克塞尔湖5米厚的冰盖上坠毁，导致约730升柴油以及少量合成润滑油和液压油泄漏。麦克默多车站的工作人员立即做出反应，允许在坠机后四天内启动清理工作。然而，由于冰层状况和2月初不可避免的田野季节结束，至少有一半泄漏的液体无法找回，无法进一步进入湖址。这些流体将被困在冰中，直到下一个春季(2003年12月)融化季节开始。该地点将于2003年11月开放，届时可采集冰芯和水样进行详细分析。麦克默多干谷LTER研究小组的成员提交了三份SGER提案(0346316、0346272和0347219)，以更好地记录碳氢化合物在湖冰和湖水中的命运和运输。协调研究工作的目标是了解自漏油事件以来发生的物理、化学和生物变化，以及漏油事件的长期影响(如果有的话)。该项目的这一部分将记录直升机流体在湖冰中的自然衰减，并有两个主要目标：1)通过评估这次坠机造成的弗莱克塞尔湖冰脂成分的变化来评估湖泊生态系统的干扰程度。事故前湖水和表层沉积物中分析的脂肪将与污染源(喷气燃料、润滑油和传动液)以及事故后冰盖样本、湖水样本和表层沉积物进行为期两年的比较。2)确定冰盖中溢出流体的自然衰减水平(蒸发和生物降解)将被量化，并评估生物降解对冰盖中溢出流体成分的影响。研究生将参与这项研究。

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.