Sciency Thoughts: Keystone XL Pipeline

Saturday, 2 November 2019

Leak from Keystone Pipeline causes major pollution incident in North Dakota.

A leak from the Keystone Pipeline has led to about 1.4 million litres of crude oil being released into wetlands in Walsh County, North Dakota. The leak was discovered on Tuesday 29 October 2019, causing pipeline owners TC Energy to shut down that portion of the pipeline while maintenance work is carried out. The leak presents no immediate threat to Human health, according to the North Dakota Department of Environmental Quality, as the wetlands where the spill occurred are not used as a source of water for Human consumption, but the impact of the spill on local wildlife is likely to be severe and potentially long lasting.

Oil spill in Walsh County, North Dakota, from a leak on the Keystone Pipeline in October 2019. Taylor DeVries/North Dakota Department of Environmental Quality/AP.

Oil spills are potentially harmful to aquatic life in a variety of ways. Most obviously it can coat the outside of organisms, causing damage to external structures such as the feathers of Birds and fur of Mammals, as well as smothering many aquatic invertebrates and plants. It also contains a variety of chemicals which can be directly toxic upset the hormonal balance of many animals. Oil also impedes the feeding of aquatic organisms, coating both food and feeding organs, but provides an excellent food source for Bacteria, which can lead to Eutrophication events - dramatic increases in Bacteria numbers, which then use all the oxygen in the water, leading other organisms to asphyxiate.

The Keystone Pipeline began operation in 2010 and carries crude oil extracted from oil sands in the Western Canadian Sedimentary Basin to refineries in Illinois and Texas. The pipeline has suffered a number of similar leaks which have caused alarm among environmental groups, many of whom opposed the construction of the pipeline in the first place. The spills have also served to deepen opposition to the larger Keystone XL Pipeline, which is planned by TC Energy to run through Alberta, Montana, South Dakota and Nebraska. The Keystone XL Pipeline project was blocked by the Obama-administration in 2015 due to concerns about the environmental impact and economic viability of the project, but this block was overturned by the incoming Trump-administration in 2017, though the legality of this is still being challenged in several courts in the US.

Significant spill from Keystone XL Pipeline in South Dakota.

Part of the Keystone XL Pipeline has been closed down after a leak was discovered about 35 km to the south of the Ludden Pump Station in Marshall County, South Dakota, on Thursday 13 November 2017. The spill was detected by pipeline operators TransCanada, who noticed a drop in pressure in the pipeline and shut down flow while the situation was investigated. The leak was originally thought to have been quite small, with about 210 000 barrels (333 900 000 litres) of oil having been lost, however inspection of the site has suggested a much larger loss, with current estimates running at 600 000 barrels (953 900 000 litres) and environmental groups concerned that the real figure will eventually be found to be much higher. This discrepancy is thought to have been caused by the dense nature of the bituminous oil running through the pipeline, which will have resulted in a slower drop in pressure that would happen with a lighter oil fraction.

The November 2017 South Dakota spill. TransCanada.

The Keystone XL Pipeline is intended to carry crude oil from tar sands deposits in Alberta, Canada, to refineries in Illinois and Texas in the US. It been opposed at almost every stage by environmental groups concerned about the possibility of leaks such as this week's one in South Dakota, the environmentally destructive nature of extracting oil from tar sands, and the contribution of a major expansion in hydrocarbons production to atmospheric carbon dioxide and global warming. These concerns led former American President Barrack Obama to halt the construction of the pipeline in 2015, however this order was rescinded by incoming President Donald Trump in March 2017. The pipeline currently pumps oil from Alberta to a refinery in Patola, Illinois, with construction of the final leg to Texas underway.