Open-access content Tuesday 4th June 2013
The process of 'fracking' produces valuable natural gas. But as Martin Freeman explains, there are some serious drawbacks, not least, involving radon gas.
17 January 2013
With the practice of hydraulic fracturing ('fracking') given the go-ahead by the UK government, the processes is coming under close scrutiny, and several serious environmental and health concerns have been raised.
Fracking is used to extract shale gas, a potentially valuable fuel source. The method is seen by some as being key to bringing down energy costs, while reducing the UK's dependence on foreign energy supplies.
Over in the US, there's great enthusiasm for the practice; more than 40,000 fracking wells have been sunk in the last year alone. It's not difficult to understand this 'gold rush'; there's a healthy profit to be turned, and the new supplies entering the market may have the effect of reducing energy bills. Some commentators have actually attributed the slight economic recovery in the US to this new energy source, at least in part.
So it seems fairly certain that fracking will become a regular activity in various parts of the UK.
Costing the earth?
But apart from being a front-runner in the race to solve a potential energy crisis in the developed world, the process has several significant drawbacks.
One of the most serious issues concerns the release of radon, a colourless, odourless gas (see info box). It is an important consideration, because radon is the second highest cause of lung cancer after smoking and currently kills around 2,000 people in the UK each year.
Fracking could be causing higher levels of radon in buildings, and be increasing the number of buildings that contain dangerous levels of radon.
The process involves the hydraulic fracturing of rock by creating pressure deep underground. Last year, two earth tremors near Blackpool were attributed to nearby fracking operations.
For and against
Proponents of the process point out that these tremors were minor, measured at a magnitude of 2.3 on the Richter scale, and were only picked up by specialist instruments. Supporters of fracking also point out that smaller tremors have occurred from the collapse of historic mine workings, suggesting that a 'traffic light' system of seismic monitoring in micro-wells will avoid risks from tremors. Also, fracking typically occurs three to four kilometres underground, so the surface impact is minimised.
Those who oppose the process focus on the method, and purpose of the fracking operation: to fracture geological structures deep underground, to release shale gas that is then substantially captured at a single point deep in the ground.
Their concern is that a deliberately created geological disturbance may create fresh pathways for hazardous gases, including radon. Such gases would not necessarily be collected with the shale gas, but could find a way to the surface. It is suggested that the very depth of the wells and the fracturing may have the effect of producing a 'cone effect' of emissions, causing a wider area to be at risk on the surface with certain types of geology.
The effects of radon are already widely documented, and the link between radon exposure and death from lung cancer is proven.
Radon is a killer, and its incidence in buildings needs to be metered and reduced, something that government departments, regulators and the industry are working towards achieving. The radioactive gas comes from the soil, and when it enters a building it causes a serious health risk if it accumulates to excessive levels. The amount of radon in a building is influenced by a combination of the local geology beneath it and the extent of the pathways through which it can escape.
A reasonable person would accept that a deliberate disturbance in underground geology by a fracking process, could result in changes to the local geology beneath buildings. This, in turn, could cause the buildings to become aversely affected by increased radon emissions.
Since the only way to know if a building is affected by radon is to test the building (radon cannot be seen or smelt), it seems reasonable to suggest that those concerned about the possibility of fracking causing radon intrusion into their home or workplace, should test their building for radon before the fracking commences. This will determine whether there is an existing radon problem, which pre-dates any fracking and needs to be mitigated.
Regardless of whether or not there was an initial problem (and whether any mitigation work to the property was carried out), repeat testing should be conducted at the property after the fracturing has been done and the wells have been sunk in the area.
If this becomes standard practice, local resident groups may wish to pool their findings to establish a probability as to whether the gas extraction activity has created a new problem or exacerbated an existing one. Because radon testing is inexpensive and simple, this would seem to be the best course of action, but a precautionary approach needs to be adopted for the present, until sufficient data has been accumulated to define exactly what side effects, if any, occur.
The facts: radon
Radon is a naturally occurring element that emanates from the ground across the world. It is formed from the radioactive decay of uranium in soil and is considered to be carcinogenic to humans.
Martin Freeman is managing director of environmental consultancy PropertECO and technical affairs spokesman for The Radon Council