Research into Potential Impact of Shale Gas Exploration

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1 Research into Potential Impact of Shale Gas Exploration STUART M E Potential groundwater impact from exploitation of shale gas in the UK. British Geological Survey Open Report, OR/12/ Summary This report is a desk study to evaluate the potential risks to groundwater in the UK from exploitation of shale gas. As yet there is little information for UK so we need to look to the USA experience for transferable information. The UK may possess considerable reserves of shale gas. Significant areas include the Widmerpool Gulf, near Nottingham, and the Elsewick field near Blackpool. Work has begun near Blackpool. Hydraulic fracturing ( fracking ) in combination with horizontal drilling is an essential part of the shale gas production process and has been in use in the USA since about Extraction involved drilling of deep horizontal wells and enhancing the natural permeability of the shale by hydraulic fracturing. Fluid is introduced at a rate sufficient to raise the downhole pressure above the fracture pressure of the formation rock. The stress induced by the pressure creates fissures and interconnected cracks that increase the permeability of the formation and enable greater flow rates of gas into the well. Groundwater may be potentially contaminated by extraction of shale gas both from the constituents of shale gas itself, from the formulation and deep injection of water containing a cocktail of additives used for hydraulic fracturing and from flowback water released during gas extraction which may have a high content of saline formation water. Shale gas is predominantly methane of thermogenic origin with low percentages of C2 (ethane) and C3 (propane) hydrocarbons. Its 13C isotopic signature allows it to be distinguished from shallow biogenic methane in the subsurface. Documented instances of groundwater contamination from the USA are all related to the leakage of methane into groundwater. Fracking chemicals include hydrochloric acid, polyacrylamide, mineral oil, isopropanol, potassium chloride and ethylene glycol and low concentrations of ph buffers, corrosion inhibitors, biocides and gelling agents. The large volumes of water required may also put pressure on groundwater resources with impacts on other uses and groundwater dependent ecosystems. Reuse of flowback water involves treatment to remove high TDS. For UK we need to determine whether fields likely to be exploited for shale gas are overlain by significant aquifers. For aquifers at outcrop the vulnerability of groundwater to surface pollution from operations and flowback water can be informed by existing vulnerability mapping and other information. The vulnerability of groundwater to pollution from fracking operations and shale gas requires the determination of the relative depths of groundwater and shale gas reservoirs and the nature of the intervening strata.

2 The Royal Society and The Royal Academy of Engineering Shale gas extraction in the UK: a review of hydraulic fracturing Summary The health, safety and environmental risks associated with hydraulic fracturing (often termed fracking ) as a means to extract shale gas can be managed effectively in the UK as long as operational best practices are implemented and enforced through regulation. Hydraulic fracturing is an established technology that has been used in the oil and gas industries for many decades. The UK has 60 years experience of regulating onshore and offshore oil and gas industries. Concerns have been raised about the risk of fractures propagating from shale formations to reach overlying aquifers. The available evidence indicates that this risk is very low provided that shale gas extraction takes place at depths of many hundreds of metres or several kilometres. Geological mechanisms constrain the distances that fractures may propagate vertically. Even if communication with overlying aquifers were possible, suitable pressure conditions would still be necessary for contaminants to flow through fracture. More likely causes of possible environmental contamination include faulty wells, and leaks and spills associated with surface operations. Neither cause is unique to shale gas. Both are common to all oil and gas wells and extractive activities. Ensuring well integrity must remain the highest priority to prevent contamination. The probability of well failure is low for a single well if it is designed, constructed and abandoned according to best practice. The UK s well examination scheme was set up so that the design of offshore wells could be reviewed by independent, specialist experts. This scheme must be made fit for purpose for onshore activities. Effects of unforeseen leaks or spills can be mitigated by proper site construction and impermeable lining. Disclosure of the constituents of fracturing fluid is already mandatory in the UK. Ensuring, where possible, that chemical additives are non-hazardous would help to mitigate the impact of any leak or spill. Concerns have also been raised about seismicity induced by hydraulic fracturing. Natural seismicity in the UK is low by world standards. On average, the UK experiences seismicity of magnitude 5 ML (felt by everyone nearby) every twenty years, and of magnitude 4 ML (felt by many people) every three to four years. The UK has lived with seismicity induced by coal mining activities or the settlement of abandoned mines for a long time. British Geological Survey records indicate that coal mining-related seismicity is generally of smaller magnitude than natural seismicity and no larger than 4 ML. Seismicity induced by hydraulic fracturing is likely to be of even smaller magnitude. There is an emerging consensus that the magnitude of seismicity induced by hydraulic fracturing would be no greater than 3 ML (felt by few people and resulting in negligible, if any, surface impacts). Recent seismicity induced by hydraulic fracturing in the UK was of magnitude 2.3 ML and 1.5 ML (unlikely to be felt by anyone). The risk of seismicity induced by hydraulic fracturing can be real-time seismic monitoring so that operators can respond promptly. Monitoring should be carried out before, during and after shale gas operations to inform risk assessments. Methane and other contaminants in groundwater should be monitored, as well as potential leakages of methane and other gases into the atmosphere. The geology of sites should be

3 characterised and faults the UK s regulators to manage potential hazards, inform local planning processes and address wider concerns. Monitoring of any potential leaks of methane would provide data to assess the carbon footprint of shale gas extraction. Moore, V., Beresford, A., & Gove, B. (2014) Hydraulic fracturing for shale gas in the UK: Examining the evidence for potential environmental impacts. Sandy, Bedfordshire, UK: RSPB. Summary High-volume hydraulic fracturing in combination with horizontal drilling are key techniques that have enabled the economic production of unconventional, onshore natural gas resources from shale gas plays. While the rapid expansion of shale gas production has dramatically changed the energy landscape in the United States, recent scientific findings show evidence for contamination of water resources and point to a range of environmental challenges arising from the process. It is, therefore, vital that the emerging shale gas industry in the UK benefits from the lessons learned from the US experience. Fit-for-purpose and strongly enforced government regulations are needed to ensure all reasonable protection is afforded to the environment during the exploratory and production stages of shale gas development. Given the potential to cause significant, and in some cases irreversible, environmental damage, eg accidental spills, it is vital that the Government s planning authorities and regulators adopt a precautionary approach to high-volume hydraulic fracturing for shale gas in the UK. It is also appropriate that operators bear the full costs associated with remediation should they, for instance, go out of business. The objectives of this evidence report are to examine and review available evidence on: The potential environmental impacts of hydraulic fracturing and shale gas extraction, in general The adequacy of practices and policies currently being developed and implemented in the UK to mitigate these impacts. In addition, the report involves a high-level vulnerability assessment of the water-related and ecological threats by considering how the industry is likely to evolve and how it will interact with the natural environment given what we know about both the nature of the industry, and the ecological and water body receptors likely to be affected. The range of this analysis has been restricted to the current (13th) and proposed (14th) onshore oil and gas licensing rounds (mainland Britain) or countries within the UK where data is readily available. However the findings have relevance throughout the UK and beyond. The key environmental impacts, addressed in this report, are grouped into the following categories: (i) Risk to the water environment (ii) Risk of ecological impacts

4 (iii) Risk of climate change impacts (i) Risk to the water environment As with all drilling operations, blowouts and equipment failures can lead to leaks to surface- and ground-water bodies. The high pressures and volumes of fracturing fluids or wastewaters involved in high-volume hydraulic fracturing exacerbate such risks. There is evidence in the literature that spatially links groundwater contamination by methane with areas of shale gas exploitation in the US. Surface spillage of flowback wastewaters has also been documented, exposing ground- and surfacewater and the wider environment to the often toxic components of fracturing fluid and flowback wastewater, eg naturally occurring radioactive materials, diesel, metals and high salinity. Despite rigorous enforcement of regulations, accidents do happen: hence we conclude that shale gas development poses a relatively low probability but very high impact risk to surface and groundwater. High-volume hydraulic fracturing has been shown to induce earthquakes in the northwest of England. Although literature suggests the risks from these events are low, evidence from the Cuadrilla test site in Lancashire showed damage had occurred to, and compromised the integrity of, the well casing, designed to protect groundwater from contamination. Increased demand on water resources is another issue that needs consideration. A recent government report, produced by AMEC (2013), estimated that the UK shale gas industry could require up to 9 million m 3 of water per year, amounting to a total of 144 million m 3 over a 20-year period. The location and timing of demand will be critical. A large concentration of extraction activities in areas already under water stress could place unsustainable stress on the environment. This view is supported by the water industry trade association Water UK (2013), which highlights that where water is in short supply there may not be enough available from public water supplies or the environment to meet the requirements for hydraulic fracturing. (ii) Risk of ecological impacts Among the risks to ecology, habitat loss and fragmentation (of habitats), and disturbance to wildlife are likely to be the most serious. Shale gas exploitation could involve significant land take with up to 120 well pads planned to be operational in the UK over the next two decades under the high activity scenario1, each occupying up to three hectares of land and comprising between 6 24 wells (AMEC, 2013). The development of well pads will result in the clearing of the areas for industry infrastructure, with potential impacts on sensitive species being felt well beyond the assumed well pad footprint (eg noise, light, atmospheric pollution). The drilling and hydraulic fracturing process will, at times, be a 24-hour/7-day per week operation with associated visual and noise impacts. Disturbance from drilling can be compounded by hundreds of truck movements required to shift equipment, materials and wastes, including flowback and produced wastewaters contaminated with highly-saline mineral compounds and naturally occurring radioactive materials. As a result, careful consideration will need to be given to location and timing of construction of well pads in order to avoid negatively impacting protected and sensitive species.

5 (iii) Risk of climate change impacts The exploitation of shale gas must be seen within the context of the UK s legally binding commitments to reduce greenhouse gas emissions by 80% by Proponents of natural gas suggest it is a cleaner transition fuel to replace coal in the process of decarbonisation. However, critics raise concerns that a dash for gas risks diverting effort from the expansion of renewable energy, placing us on a trajectory that would inevitably lead to us missing the national greenhouse gas commitments. There is evidence to suggest greenhouse gas emissions associated with the development and production of gas, along with unregulated fugitive methane emissions to air, could make shale gas as dirty as the coal it is expected to replace in our bid for cleaner energy. Given that the evidence does not yet justify supporting the use of shale gas as a transition fuel, and that this will also divert resources aimed at decarbonisation and renewable energy development, we propose that other justifications are needed to rationalise the growth of the onshore unconventional gas industry in the UK. Broderick. J., et al: 2011, Shale gas: an updated assessment of environmental and climate change impacts. A report commissioned by The Co-operative and undertaken by researchers at the Tyndall Centre, University of Manchester ewsandevents/news/research/pdfs2011/shale-gas-threat-report.pdf Summary The analysis within this new report addresses two specific issues associated with the extraction and combustion of shale gas. Firstly, it explores the environmental risks and climate change implications arising from shale gas extraction. Secondly, it outlines potential UK and global greenhouse gas (GHG) emissions arising from an updated range of scenarios built using the latest predictions of shale gas resources. Since our earlier analysis, a range of reports and journal articles on shale gas have been published, giving the impression of a substantial increase in meaningful data alongside a more developed understanding of the issues. However, whilst the knowledge base has certainly improved, closer scrutiny of the new information reveals that much of it builds on similar and very provisional data sources, and accordingly represents only a small improvement in the robustness of earlier analyses. Consequently, and despite there now being a much wider literature on shale gas, the earlier report s cautionary note, that a key issue in assessing shale gas... has been a paucity of reliable data, still holds. To date the only significant development and exploitation of shale gas has been in the United States (US). However, even there significant environmental issues remain unresolved, and reserve estimates show little sign of stabilising (increasing seven times in the last four years). Inevitably therefore, assessments of the environmental impacts, reserve potential and subsequently the

6 greenhouse gas emissions for the European Union (EU) and the UK s fledging shale gas sector, remain subject to significant levels of uncertainty. In view of continued ambiguity as to the robustness of quantitative data, considerable effort has been made to ensure the veracity of the information in this report. Ultimately however, the analyses can only be as accurate as the information and the assumptions upon which it draws. Despite these uncertainties, several clear conclusions arise and can be used to inform decisions on the appropriateness or otherwise of developing a shale gas industry within the UK. It is evident that shale gas extraction does not require the high energy and water inputs at the scale of other unconventional fuels, such as oil derived from tar sands. Nevertheless, there are several routes by which shale gas extraction may pose potentially significant risks to the environment. Concerns remain about the adequacy of current UK regulation of groundwater and surface water contamination and the assessment of environmental impact. Although amenable to stringent regulatory control, risks of contamination cannot be fully eliminated. Consequently, if shale gas is to make a significant contribution to the UK s energy mix, a rigorous monitoring regime is essential to contain the risks of contamination, from thousands of wells, within acceptable levels. Similarly, fugitive emissions arising from the hydraulic fracturing process and emitted around the wellhead could be significant and increase the footprint of shale gas substantially, although with effective capture and process technologies, emissions levels not dissimilar from those associated with natural gas extraction appear possible in principle. If fugitive emissions are to be kept to acceptable levels and not significantly skew the balance between upstream and point of use emissions, it is again paramount that appropriate regulatory, monitoring and enforcement regimes are developed and in place prior to full scale extraction. Turning to the climate change implications of shale gas extraction and combustion, the report demonstrates that in an energy-hungry world (e.g. EIA energy demand projections 2011) and in the absence of a stringent global emissions cap, largescale extraction of shale gas cannot be reconciled with the climate change commitments enshrined in the Copenhagen Accord (2009). This is principally an issue of the very short time frames remaining in which to reduce emissions to levels, consistent with the science, and which would hold the increase in global temperature below 2 degrees Celsius. Given the Accord also stipulates mitigation efforts need to be on the basis of equity, the constraints of the Accord are germane particularly to the industrialised (Annex 1) nations. Shale gas subject to best practice extraction and subsequently combusted in high efficiency combined cycle gas turbine (CCGT) powerstations will deliver power at lower emissions per unit of electricity generated than is possible from coal fired generation. However, even if there were to be a rapid transition from coal to shale gas electricity, this could still not be reconciled with the UK s 2 C commitments under either the international Copenhagen Accord or its own national Low Carbon Transition Plan. If instead, conservative rates of recovering shale gas from the latest estimate of global reserves were achieved and only half subsequently combusted by 2050, shale gas could occupy over a quarter of the remaining CO2 emissions budget associated with a reasonable chance of avoiding 2 C of warming. Atmospheric carbon dioxide levels would be expected to rise by between 5 and 16 parts per million by volume (ppmv), with a mid-range of 11ppmv. Whether shale gas substitutes for higher carbon energy supply or meets new energy demand in the UK, it risks doing so at the expense of investment in much lower carbon supply. Energy companies,

7 investment markets and broader UK institutions are all familiar with fossil fuels, and any short-term financial benefit that may accrue to shale gas heating and electricity risks reinforcing lock-in to established supply routes. This has two further implications. Firstly, it reduces the drive for innovation and the scope for learning by doing, with the UK subsequently less well equipped to compete in renewable and low-carbon markets elsewhere. Secondly, any investments in shale gas infrastructure over the coming decade would rapidly become a stranded economic asset if the UK were to respect its 2 C commitments. Alternatively, government may be persuaded to withdraw from national and international obligations, and instead sanction continued use of existing high capital value, and high carbon, shale gas infrastructure. This report illustrates how a 32bn capital investment in shale gas could potentially displace up to 12GW of offshore or 21GW of onshore wind capacity and raise the prospect of the UK not meeting its renewable energy obligations. To summarise: Irrespective of whether UK shale gas substitutes for coal, renewables or imported gas, the industry s latest reserve estimates for just one licence area could account for up to 15% of the UK s emissions budget through to Therefore, emissions from a fully developed UK shale gas industry would likely be very substantial in their own right. If the UK Government is to respect its obligations under both the Copenhagen Accord and Low Carbon Transition Plan, shale gas offers no meaningful potential as even a transition fuel. Moreover, any significant and early development of the industry is likely to prove either economically unwise or risk jeopardising the UK s international reputation on climate change. Against such a quantifiable and stark evaluation, it is difficult to conclude other than the UK needs to invest in very low carbon energy supply if it is to both abide by its international obligations and support economically sustainable technologies. Healy, D Hydraulic Fracturing or Fracking : A Short Summary of Current Knowledge and Potential Environmental Impacts. A Small Scale Study for the Environmental Protection Agency (Ireland) under the Science, Technology, Research & Innovation for the Environment (STRIVE) Programme Summary Published peer-reviewed data suggest that there is a low and probably manageable risk to ground water from fracking, whereas the potential impacts on the atmosphere from associated methane emissions and the risks of increased seismicity are less well known. However, the total number of published, peer-reviewed scientific studies remains low, and it is therefore prudent to consider and research in detail the full range of possible risks from fracking operations, including their magnitudes and uncertainties, and the potential environmental impacts of these risks in the exploitation of shale gas. The published reports (MIT, 2011; University of Texas, 2012) and those due to be published by the US EPA, a new EU Working Group on Shale Gas Regulation, and the International Energy Agency, will together provide a richer and more robust foundation for informed decision making in Europe. Much of the coverage to date in the traditional media and on the World Wide Web is not peerreviewed and is often misinformed. Critical evaluations of shale gas fracking and the potential impacts on the environment must be based on peer-reviewed, scientific analyses of quantitative data. Agencies responsible for regulating or monitoring the environmental impacts of shale gas

8 development need to be at the forefront of this effort (SEAB, 2011a). The design of any national regulatory framework to protect the environment from hydraulic fracturing operations should start with the supranational European Union directives and recommendations from working groups in progress. Marshall, J Impacts of the exploration for and extraction of unconventional oil and gas on water and wastewater service providers. Briefing Paper. Water UK pdf?dl=0 Excerpt 1) Water quality The process poses possible risks to the quality of the water environment, particularly groundwater. Sources of contamination include: the surface spillages of chemicals, diesel and other materials at a drilling site; poor well design and construction with subsequent failure; and the hydraulic fracturing process, including the use of biocides and chemical friction reducers in fracturing fluid. A 2012 report by the Royal Society and Royal Academy of Engineering concludes that risks can be managed given a properly implemented and enforced regulatory framework. In particular it concludes that the probability of well failure is low if it is designed, constructed and abandoned according to best practice and that the risk of fractures propagating from shale formations to reach overlying aquifers is very low. In addition, chemicals added to the water to enable fracturing to take place (for example biocides and friction reducers) are subject t to approval by environmental regulators and should be classified as non-hazardous. A greater risk would appear to be from surface spillages of chemicals and other materials. It is therefore important that on-site storage of chemicals is managed by proper site practices. The report published by Public Health England considers these specific risks and concludes that good on-site management and appropriate regulation of all aspects...are essential to minimise the risk to the environment and public health 2) Water quantity The extraction process uses pressurised water to hydraulically fracture the gas-bearing shale strata. The quantities of water needed to do so vary by site but can reasonably be expected to be in the region of 10 to 20Ml per fracture. Such a demand, whilst not being nationally significant, could have an impact on local water resources. This demand may be met from a number of sources including from the public water supply, from direct abstraction, from water transported by tanker from other areas or from recycling and reuse of treated flowback or produced water. The pressure on local water resources will depend in part on the pace and extent of the extraction process, although the potential to reclaim and reuse large proportions of water from each site promises to reduce the risks to local water resources. Where water is in short supply there may not be enough available from public water supplies or the environment to meet the requirements for hydraulic fracturing. Oil and gas operators are therefore encouraged to engage with water companies as early as possible to ensure their needs can be met without reducing the security of supply to existing customers.

9 3) Wastewater management Wastewater companies may also be asked to accept discharge of effluents recovered from the process for treatment at wastewater treatment works. This water will contain a proportion of the fluids used initially to aid fracturing, high concentrations of salinity (TDS) and potentially low amounts of naturally occurring radioactive material (NORM). The feasibility o f treating this water at a municipal wastewater treatment works will depend on the volume and concentration of the wastewater in relation to the size of the treatment works and the concentrations of NORM present. It is unlikely that the standard wastewater treatment works will be able to manage wastewater from unconventional oil and gas. Engagement and dialogue The water industry believes that timely and constructive consultation and engagement by operators and regulators is essential to aid planning. These discussions will be key to understanding water and wastewater services requirements in the short and longer term, as well as helping to identify and resolve potential issues. Key areas of interest for these discussions will include: The extent of baseline monitoring being proposed to assess impacts on the quality and quantity of local water resources; Plans relating to site water management, especially in relation to water reuse to improve understanding of local impacts; Shale gas company development plans including scenarios for expansion within a local area and what this means for short and longer term demand for water at specific locations; The expected volumes and chemical and biological composition of wastewater as well as preferred disposal routes. This dialogue will allow water and wastewater service providers to make informed decisions about potential solutions, as well as risks and any mitigation required, to ensure that the provision of services to shale gas companies does not adversely impact water resources or the natural environment more generally. Harrison G., Parkinson S. and McFarlane G., Shale gas and fracking: examining the evidence. Scientists for Global Responsibility (SGR) and the Chartered Institute of Environmental Health (CIEH). Summary The UK is at an energy cross-roads. Many large power stations are closing, and major policy decisions are being made about replacing energy infrastructure. This is against a background of concern about energy prices, energy security and climate change. Fracking the hydraulic fracturing technique used to extract natural gas and oil from rocks such as shale has emerged as a means of opening up a potentially large new UK energy source that some proponents claim will bring down energy bills. Others suggest that, on the contrary, the development or persistence of gas-fired energy infrastructure in the UK locks us into the unpredictable and increasingly expensive international gas market, and threatens the environment. They argue that we should pursue a rapid transition to a low-carbon economy as a much more effective way of improving energy security, reducing bills and tackling climate change.

10 With fracking for shale gas being relatively new, there are many gaps in the scientific literature regarding its impacts. As a result, the public debate often relies on information from either anecdotal sources or the industry itself, which stands accused of misleading the public. In spring 2013, the Advertising Standards Authority upheld six complaints, and partially upheld another, against oil and gas company Cuadrilla for misleading advertising, exaggeration and/or unsubstantiated claims in its marketing. However, an increasing volume of impartial, evidence-based information now exists. This briefing draws on peer-reviewed literature and independent expert opinion to present an accessible yet robust and fully-referenced overview of the main issues, which readers may then explore in more detail. It challenges some of the commonly-repeated claims that, in many cases, fail to stand up to proper scrutiny. Focusing specifically on the UK situation, this briefing examines: the areas under consideration for fracking for shale gas in the UK; the potential local environmental and health impacts, including earthquake risk, water and ground contamination, water-use and waste-water, local air quality, and public health risks; the regulatory regime intended to deal with local environmental and health risks; the implications of widespread shale gas extraction for efforts to tackle climate change; socio-economic issues, including energy prices, energy security, jobs and community benefits, and house prices; levels of public opposition to fracking; and whether we can manage without shale gas. In this briefing, we have summarised key evidence concerning the environmental, health and wellbeing, and socio-economic aspects of fracking for shale gas in the UK. In particular, we have critically examined some of the most common industry and government claims, drawing extensively on independent academic and expert literature. We have found several areas of concern. Regulation of the industry in the UK is currently inadequate, although it is stricter than in the US, thus somewhat reducing the potential for local environmental impact by comparison. With technological advances and an improved regulatory environment, groundwater contamination risks could conceivably be reduced to an acceptable level, although there is much to do to reach that point. Furthermore, the requirement for vast quantities of freshwater (expected to become scarcer under climate change), which require road transportation, is unlikely to be resolved. Confidence in the practice is undermined by a series of disingenuous claims made by both the Government and industry. Prpich G., Coulon F. and Anthony A.J., Review of the scientific evidence to support environmental risk assessment of shale gas development in the UK. Science of The Total Environment Volumes , 1 September 2016, Pages Available via Highlights Shale gas operations involve environmental risks.

11 Scientific evidence to support risk assessments about shale gas is amassing. We describe how environmental risk assessment is used to gather and organise evidence. Evidence generated in the US might not be transferable to other regions. Abstract Interest in the development of shale gas resources using hydraulic fracturing techniques is increasing worldwide despite concerns about the environmental risks associated with this activity. In the United Kingdom (UK), early attempts to hydraulically fracture a shale gas well resulted in a seismic event that led to the suspension of all hydraulic fracturing operations. In response to this occurrence, UK regulators have requested that future shale gas operations that use hydraulic fracturing should be accompanied by a high-level environmental risk assessment (ERA). Completion of an ERA can demonstrate competency, communicate understanding, and ultimately build trust that environmental risks are being managed properly, however, this assessment requires a scientific evidence base. In this paper we discuss how the ERA became a preferred assessment technique to understand the risks related to shale gas development in the UK, and how it can be used to communicate information between stakeholders. We also provide a review of the evidence base that describes the environmental risks related to shale gas operations, which could be used to support an ERA. Finally, we conclude with an update of the current environmental risks associated with shale gas development in the UK and present recommendations for further research. Greenpeace UK, Fracking: What s the Evidence? Not peer reviewed and potentially biased, but interesting and quite balanced approach. Stuart, M. Shale Gas Exploitation [online article, undated]. British Geological Survey. Summary of webpage Shale gas is predominantly methane of thermogenic origin and the UK may possess considerable reserves at depth. Significant areas include the Lancashire and Cheshire Basins where exploration has begun. Hydraulic fracturing ( fracking ) in combination with horizontal drilling is an essential part of the shale gas production process. Groundwater may be potentially contaminated by extraction of shale gas both from the constituents of shale gas itself, from the formulation and deep injection of water containing a cocktail of additives used for hydraulic fracturing and from flowback water released during gas extraction which may have a high content of saline formation water. Documented instances of groundwater contamination from the USA are almost all related to the leakage of methane into groundwater. The large volumes of water required may also put pressure on groundwater resources with impacts on other uses and groundwater dependent ecosystems. The

12 vulnerability of groundwater to pollution from fracking operations and shale gas requires the determination of the relative depths of groundwater and shale gas reservoirs and the nature of the intervening strata. The pathways for pollution from surface activities and loss of casing integrity also need to be considered. As yet there is little information for UK so we need to look to the USA experience for transferable knowledge. Frantz, M W, Wood, P B, Sheehan, J, and George, G Demographic response of Louisiana Waterthrush, a stream obligate songbird of conservation concern, to shale gas development. The Condor 120: The results show that as shale gas development has expanded in the area, nest survival and productivity and riparian habitat quality have all declined. At the same time, the size of individual waterthrush territories has increased, suggesting birds need to range farther to find sufficient resources. This study is one of the first to demonstrate that shale gas development can affect songbird reproductive success and productivity, both directly through the presence of fracking infrastructure and indirectly through effects on habitat quality.