Recent attention regarding the impacts of oil and gas development and exploitation has focused on the unintentional release of hydrocarbons into the environment, whilst the potential negative effects of other possible avenues of environmental contamination are less well documented. In the hydrocarbon-rich and ecologically sensitive Mackenzie Delta region (NT, Canada), saline wastes associated with hydrocarbon exploration have typically been disposed of in drilling sumps (i.e., large pits excavated into the permafrost) that were believed to be a permanent containment solution. However, failure of permafrost as a waste containment medium may cause impacts to lakes in this sensitive environment. Here, we examine the effects of degrading drilling sumps on water quality by combining paleolimnological approaches with the analysis of an extensive present-day water chemistry dataset. This dataset includes lakes believed to have been impacted by saline drilling fluids leaching from drilling sumps, lakes with no visible disturbances, and lakes impacted by significant, naturally occurring permafrost thaw in the form of retrogressive thaw slumps. We show that lakes impacted by compromised drilling sumps have significantly elevated lakewater conductivity levels compared to control sites. Chloride levels are particularly elevated in sump-impacted lakes relative to all other lakes included in the survey. Paleolimnological analyses showed that invertebrate assemblages appear to have responded to the leaching of drilling wastes by a discernible increase in a taxon known to be tolerant of elevated conductivity coincident with the timing of sump construction. This suggests construction and abandonment techniques at, or soon after, sump establishment may result in impacts to downstream aquatic ecosystems. With hydrocarbon development in the north predicted to expand in the coming decades, the use of sumps must be examined in light of the threat of accelerated permafrost thaw, and the potential for these industrial wastes to impact sensitive Arctic ecosystems.
最近关于石油和天然气开发和勘探的影响的关注力都集中在了意外泄漏到环境中的碳氢化合物，同时其他的环境污染可能途径的潜在负面影响也没有得到很好的记录。 在碳氢化合物丰富并且生态敏感的Mackenzie三角地带（NT, 加拿大）， 与油气勘探产生的含盐废水经常被倾倒在钻井污水坑（比如挖掘到冻土层的大坑）并被当作是永久的的密封控制解决方案。 然而，将冻土层作为垃圾控制解决方案一旦失败将影响这一敏感环境中的湖泊。在本研究中，我们结合了古湖泊方法和广泛的现有水化学数据库来测试了这些钻井污水坑的水质的影响。 这些数据库包括已经被钻井污水坑中泄漏的污水污染的湖泊，没有被明显干扰的湖泊，被严重影响的湖泊，自然发生的大面积冻土融解。 我们指出了和被控制的区域的湖泊相比，那些受钻井污水坑影响的湖泊的湖水导电性水平已经严重上升了。和本研究中所有的其他湖泊相比，那些被污水坑影响的湖泊中氯化物含量也都特别升高了。 古湖泊学分析显示：无脊椎动物的聚集似乎归因于钻井污水的泄漏，得出这一结论是因为我们发现一种已知的会随着导电性上升更欢乐生长的物种在污水坑建设期间数量大大增加了。 这表明北极污水坑建设的建造和遗弃技术已经，或者在不久将来将， 对下游的水生态系统产生影响。 污水坑的使用必须进行相应的冻土解冻威胁检测以及废水对敏感极地生态环境的潜在影响的检测。