Also in this series:
Shale and water: Water requirements could pose challenges to fracking
Shale and water: is there a risk of water stress?
In a wide ranging article debunking what he regarded as many of the myths around fracking the government’s former chief scientific advisor David King said there remained what he called ‘rational’ fears around the technique.
Chief amongst these, he said, was the risk of water becoming contaminated during the process of extracting the gas or because of a spill.
“Another issue [which] has been raised which is the contamination of surface water and I think this is one of the issues that has to be dealt with with very careful legislation.”
He is not alone. Water UK, which represents all major water suppliers, is calling for “greater clarity from the shale gas industry on what its water needs are really going to be and a true assessment of the impacts.”
Dr Jim Marshall, Policy and Business Adviser at Water UK said in his July 17 speech at UK Shale 2013: “If we get it wrong then water has the potential to stop the industry in its tracks.”
What are the main concerns?
Throughout the entire fracking lifecycle there are risks associated both with the quantity of water needed and the potential contamination of drinking water supply with methane gas and chemicals.
According to a study by the United Nations Environment Programme (UNEP), “spills or leaks can … occur during the transport, mixing and storage of the water and flowback”.
According to Water UK and an AMEC report for the Department of Energy and Climate change, these risks include:
- Contamination of surface water by runoff from construction activities, spills and leaks of drilling muds, and/or from poorly managed waste water or handling of chemicals
- Contamination of groundwater by pollutants (including gas) released from the well due to well integrity failure, spillage of stored wastewaters and/or chemicals, from fracturing running through geology
In it’s own risk assessment the Environment Agency classified the loss of fracking fluid, leaks during chemical mixing and problems with borehole installation and integrity as key areas for regulation.
(Picture from EA report)
What chemicals are used in the frack fluid?
A limited number of chemicals have been approved for use by Cuadrilla so far (none of which are hazardous in the form in which they are used).
Listed online, they are: polyacrylamide friction reducer (0.075%), hydrochloric acid (0.125%), and biocide (0.005%).
For all future fracking activities, the companies must disclose the chemicals used either on their own websites or on third party websites. However, this is “subject to appropriate protection for commercial sensitivity.”
In the U.S. companies add a variety of disclosed – and non-disclosed – chemicals to the fracking fluid.
According to a report from Texas University these include: potassium chloride, guar gum, ethylene glycol, sodium carbonate, potassium carbonate, sodium chloride, borate salts, citric acid, glutaraldehyde, acid, petroleum distillate, and isopropanol.
Different chemicals are needed for different parts of the fracking process.
For example, acid helps to dissolve minerals and creating fissures in the rock. Other chemicals are added in order to prevent pipe corrosion or minimise friction between the pipe and the fluid.
Other studies have suggested that chemicals including diesel fuel, kerosene, benzene, toluene, xylene, and formaldehyde, are used in the fracking process.
The US EPA found that diesel fuel, which contains benzene and is classed as hazardous to health, was sometimes used in fluids for hydraulic fracturing within USDWs. FracFocus.org provides a list of all the disclosed chemicals used in fracking fluid in the US.
What about naturally occurring contaminants?
In addition to the chemicals added to fracking fluid, the fluid itself picks up toxins and minerals through it’s use. Much of this remains underground, but between 20-80% returns to the surface as flow-back fluid.
According to the EA, flow-back fluid from the Lancashire shale contained “Notably high levels of sodium, chloride, bromide and iron, as well as higher values of lead, magnesium and zinc compared with the local mains water that is used for injecting into the shale.”
In addition to the inorganic chemicals added to the fracking fluid, a report by the US Geological Survey found organic compounds such as naturally occurring radioactive material, BTEX, phenols, and polycyclic aromatic hydrocarbons in flowback water.
The UNEP report states: “There is a risk that fracturing the rocks might ease the migration of naturally occurring toxic substances present in the subsurface, such as mercury, lead, or arsenic.”
In the UK, fracking companies must obtain permits for the safe disposal of radioactive material. Radioactive waste is not dangerous if properly handled, however, the EA shale risk assessment does list exposure to NORM as a possible risk in shale gas exploration.
Can these chemicals contaminate drinking water?
Many fear that yes, they could.
The Environment Agency states that there is a high magnitude of risk associated with the use of chemicals, listing the consequences of spills as “contamination and loss of resources, injury, ill health or death, loss of or damage to a habitat”.
It also states that the loss of fracking fluid due to leaks or spills has a high magnitude of risk on both surface water and groundwater.
The AEA assessment for the EU notes “During the drilling stage, contamination can arise as a result of a failure to maintain stormwater controls, ineffective site management, inadequate surface and subsurface containment, poor casing construction, well blowout or component failure. If engineering controls are insufficient, the risk of accidental release increases with multiple shale gas wells.”
In the case of conventional oil and gas extraction, groundwater contamination has mainly been the result of improper disposal of wastewater, leaks during production, improperly sealed wells, and malfunctioning equipment.
With unconventional shale gas extraction there is also the added risk of fracking fluid migrating through natural and/or man-made fissures in the rock (which can be exacerbated when accompanied by seismic events) into groundwater supplies. More importantly, there is simply a great deal more channels created by fracking through which the fluid can escape.
Dr Anthony Ingraffea, professor of engineering at Cornell and co-author of the study which established fracking’s greenhouse-gas footprint said: “Because the wells are going to be fracked, and they’re going to be fracked the same way they’re being fracked all over the world, you have the potential for spills of the chemicals that go into the frack fluid, you have potential for spills of flow-back that has to be captured, transported, recycled, processed, and disposed of, so you have potential for spills either before the stuff goes down the hole or as it comes back up.”
Can water be contaminated by poor infrastructure?
Yes, there is the risk that faults in the fracking infrastructure - particularly the boreholes - could lead to contamination of groundwater.
Leaks from the boreholes can happen both during the fracking process and during the flowback stage.
Listed at a medium magnitude of risk, not only can leaked fracking fluid contaminate groundwater aquifers and surface waters but gases such as methane can also be released into the water supply.
“A concern, even if you’re only going to have a few hundred to a few thousand wells, is that some of those wells are going to leak and there’s a potential for contamination of underground sources of drinking water,” Ingraffea said.
According to a study by the University of Calgary, “cased wells are more prone to leakage than drilled and abandoned wells, and injection wells are more prone to leakage than producing wells.”
If the cement columns around the well casings are imperfectly sealed, it risks fracking fluid leaking into the water table causing water contamination or explosions according to the UNEP report.
The UK’s environment agency, in their risk assessment, identified well integrity as an area in need of research. They identify a medium magnitude of risk associated with the well closure and abandonment; meaning “pollution caused by a substance released during the exploration process continues to have an environmental impact beyond the operational phase”.
Finally, according to the EA, onsite infrastructure could be damaged due to seismic activity caused by the fracking process. This would then put aquifers, groundwater, and surface water at risk of contamination due to pollution from the escaped fracking fluid. This is classified at a medium magnitude of risk.
Are these chemicals harmful?
So far there has been no peer reviewed study officially establishing a clear human health impact from fracking.
In an assessment of 353 chemicals known to be used in fracking in the US, it was found that 25 per cent could cause cancer, 40 - 50 per cent could affect the nervous system, immune and cardiovascular systems, and more than 75 per cent could affect the skin, eyes and respiratory system.
But it’s important to note that this would depend on human exposure at significant levels.
In most of the well known cases of alleged water contamination (such as in Colorado) residents have claimed ill health, including headaches, nervous problems, skin complaints and stomach issues. However those claims have never been conclusive.
A 2012 Cornell peer-reviewed study (Bamberger et al) warned that livestock near fracking sites were falling ill and experienced neurological, reproductive and acute gastrointestinal problems after being exposed — either accidentally or incidentally — to fracking chemicals in the water or air.
The authors concede the study could not prove a direct link to fracking - but argued this was largely due to non-disclosure by the industry arguing:
“The findings illustrate which aspects of the drilling process may lead to health problems and suggest modifications that would lessen but not eliminate impacts. Complete evidence regarding health impacts of gas drilling cannot be obtained due to incomplete testing and disclosure of chemicals, and nondisclosure agreements”
Are there any risks to the land or lakes from water contamination?
If fractures extended beyond the target zone this could create unintended new vertical and/or horizontal pathways through which the fracking fluid and naturally occurring contaminants could travel.
According to the EA, this could potentially lead to the contamination not only of groundwater aquifers but also adjacent boreholes and surface water.
One study cited in the UNEP report details the impacts of nonylphenol - a chemical commonly found in fracking fluid - on fish. It finds that nonylphenol, which mimics estrogen, “can cause feminization of fish, even at concentrations not detected by normal monitoring of the fluid.” Ultimately this could lead to a male-female population imbalance and a potential rapid decline of the fish population.
Another risk mentioned by the report was to farmland due to the highly saline underground water pumped up during the process. If this produced water (which can contain high concentrations of sodium, calcium, and magnesium) is spilled onto nearby fields and not properly treated, it can “inhibit germination and plant growth while excessive sodium can change the physical properties of soil and result in poor drainage, crusting and reduced crop yields”.
The recent DECC report on fracking states: “There is no reason to expect any impacts on agriculture, and no plausible mechanism for such an impact has been proposed. Until some such possible threat has been identified, no monitoring activity would be meaningful or justified.”
In addition, the EA states that land and water can be contaminated during the transport and storage of wastes produced during fracking. This could occur off-site anytime during transport if there is an accident, at treatment plants and storage and transfer stations, as well as at water and land disposal sites.
Has water been contaminated in the US?
While many say yes, the number of official studies confirming the link between water contamination and fracking are limited.
Most recently, the EPA came under attack after a leaked slideshow suggested one of it’s scientists believed another study into water pollution in Pennsylvania should not have been stopped - after findings which may indicate leaks from fracking contaminating water.
In June the only finding by U.S. regulators of water contamination from fracking was halted by the federal government and handed over to the State of Wyoming. The final report is set to be issued in September 2014.
However, high levels of pollution were recently found in and around the Barnett Shale in Texas. Toxic substances, including arsenic, selenium and strontium, were all found at levels higher than the recommended levels in wells. The highest concentration of arsenic was 16 times the Environment Protection Agency (EPA) safety standard for drinking water.
Also, scientists at Duke University found elevated levels of methane, ethane, and propane in groundwater samples near active fracking sites in Pennsylvania. They concluded that the gases came from the fracking wells, not natural sources, and that the problem could be solved with better well casings.
Of course, there’s always the chance that people make mistakes, as was highlighted this December by Alberta's Energy Resources Conservation Board (ERCB) spokesman Darin Barter who said: "There is no amount of regulation that can overcome human error”.
This was in response to workers from Crew Energy and GasFrac who accidentally fracked directly into an underground water table in Grande Prairie, Alberta in September 2011. This resulted in 42 cubic metres of unrecoverable propane gel as well as toxic fracking fluid chemicals being injected into an aquifer about 136 metres below ground.
How is the water regulated?
In the US, water usage, treatment, and disposal is largely regulated by the individual states.
More generally however, fracking is exempt from the Safe Drinking Water Act. Also, under the US Clean Water Act, the definition of a pollutant was outlined so as not to include “water, gas, or other material which is injected into a well to facilitate production of oil or gas.”
Known as the ‘Halliburton loophole’, these exemptions were put into place under the George W. Bush administration in 2005.
In the UK, the Environment Agency assesses the risk on a site-by-site basis to determine the specific permits required.
Also, as a recent DECC report states, regulators take a “risk-based approach to the regulation of the use of chemicals in shale gas fracking activities.”
Factors such as a geological assessment, the casing design, and fracking fluid composition must be provided to the Environment Agency (or, in the case of Wales and Scotland, the Natural Resources Wales or the Scottish Environment Protection Agency) in order to determine the risks and whether a permit is required.
More specifically, companies must apply for an abstraction permit if more than 20 cubic metres per day of water is to be abstracted from surface or groundwater bodies. As DECC points out, “the water requirements for hydraulic fracturing are likely to be much greater than this limit”.
However, if the water is to be sourced from a mains supply then the company must ensure that it can meet the conditions of the abstraction permit under which the mains is operating.
According to the IoD, it is unlikely that Cuadrilla will need a permit for groundwater activity so long as only substances classified as ‘non-hazardous pollutants’ are used in the fracking fluid.
Regarding the fracking fluid, a permit is required from the Environment Agency “where fluids containing pollutants are injected into ground, where they may enter groundwater. This may also be needed if the activity poses a risk of mobilising natural substances that could then cause pollution,” the DECC report explains.
Companies will also be required to get a permit for safe disposal of the waste water produced during the fracking process.
It’s interesting to note, that Cuadrilla fought to be exempt from several regulations. Documents and emails obtained by Energydesk through a Freedom of Information (FOI) request show the extent of lobbying by Cuadrilla to be exempt from the 2011 regulations on how it monitored and disposed of waste products from drilling.
Unlike in the United States however, Cuadrilla failed to create their own loophole.
A full list of permits required for the various activities and risks associated with fracking can be found in the Environment Agency’s most recent report.
Water UK is currently lobbying to have water companies incorporated into the planning process as consultees, with Marshall stressing that “direct communication links between operator and water company is essential”.
