In the Scottish Farmer Gordon Davidson reports that Professor Robert Jackson, described by Scottish Water as one of country’s leading independent experts in waste water management, has cast doubt on the gas extraction industry’s safety claims, citing years of evidence from the US that many hydrocarbon wells, sooner or later, will threaten groundwater with noxious leaks.
Professor Jackson has prepared a discussion document, ‘A Fractured Food Chain’, examining the risks of subterranean hydraulic fracturing in relation to food production on the surface.
The Herald adds that Professor Jackson, a former academic at the University of Salford hired as an independent expert to examine environmental issues by Scottish Water, said that if fracking went ahead, it risked compromising water supplies while fluid injected underground could poison groundwater, soil, crops, grazing land and livestock if it reached the surface.
Yesterday the FT reported that Scotland has announced a moratorium on underground coal gasification and has extended the review on the effects of fracking, moves that have delighted environmentalists but which will also raise fears over economic growth.
Opponents of fracking cite the negative experiences of farmers and residents around US shale gas drilling sites, but the industry in the UK has set out its stall on the basis of ‘lessons learnt’ from American mistakes, and insisted that the version of fracking planned for this side of the Atlantic would be far more benign.
It is this position that Prof Jackson has challenged, saying in his latest report that it was simply impossible to give long-term assurances that deep-drilled wells would never leak.
“Whatever the vertical distance between near-surface freshwater aquifers and river waters, and deeper shale gas deposits, boreholes drilled for shale gas will always have the potential to provide a pathway between these two regions,” he said. “Boreholes are supposed to be sealed along most of their length with cement grout between the steel piping and the rock, but many of the gas leaks associated with fracking are associated with failures in the sealing process. An article published in the New York Times in 1992 confirmed that thousands of gas wells in the United States, abandoned at the end of their productive life, became conduits for noxious liquids that bubble up from deep below the earth’s surface to kill crops and taint drinking water.
“Moreover, Schlumberger Limited, the world’s largest oilfield services company, estimates that up to 60% of gas wells leak within 30 years and, since January 2009, there have been 137 environmental regulation violations involving water contamination in Pennsylvania at 111 active wells drilled for natural gas.”
Prof Jackson stressed that released hydrocarbons were not the only issue – the mix of emollients, sealants and other chemicals pumped into the ground, with high pressure water, to drive out the gas, was also a threat. However good the post-fracking clean-up process, the sheer volume of liquid involved did not lend itself to 100% retrieval. “If any remaining injected fluid retained in the ground returns to the surface via other pathways, it may ultimately poison groundwater, soil, crops, grazing land and livestock, thereby compromising the food chain,” he warned.
And ended: “So, even if the risks of contamination are currently perceived to be low, the very serious consequences of any leak from a bored well could have a profound effect upon the food chain for current and future generations. If Schlumberger’s estimate of up to 60% of gas wells leaking within 30 years of their completion is correct, it is highly unlikely that even robust regulation will detect all well ‘failures’, in which case the ground may not be the only thing that is fractured.”