The project will identify, characterise and parameterise the multiple direct and indirect pathways within the shallow subsurface and the atmosphere (and across interfaces), which link sources of contamination and hazards associated with shale gas (SG) operations to human and sensitive environmental receptors, and surface infrastructure.
For each component of the domain (Water, Air, Solid Earth), Source-Pathway-Receptor combinations will be examined and then integrated in a probabilistic risk assessment (PRA) framework for quantification of the risks to humans, infrastructure and the environment. A key aspect of the study will be to understand how the risk profile evolves over the life cycle of shale gas operations - from single site to multiple operations across an area.
The focus will be on investigating the processes that affect and influence the near-surface (i.e. <400 m bgl) Source-Pathway-Receptor combinations (and their interactions). Processes that will be investigated include; hydro-geochemical controls on contaminant behaviour and transport, climatological and chemical controls on air quality, and attenuation of ground motion e.g. from seismic events. The on-going environmental monitoring at the shale gas sites in North Yorkshire and Lancashire, along with their detailed conceptual and geological models will provide rich and continuous quality-assured high precision datasets and information. The sites represent different types of shale gas operation in different geo-environmental settings. Information from these sites, along with other non-UK sites where project partners have worked, will be a starting point, with additional data from UKGEO supplementing the evidence base. Analysis of these data will then support the design of experiments at UKGEO and other sites to improve confidence in process understanding and test different aspects of the risk model under controlled conditions, quantifying properties and better characterising/quantifying uncertainty through evaluation of the sensitivity of environmental and human receptors.
The experiments will also consider non-shale gas-related activities such as analogues and crowd-sourcing of information on ground movement. Attention will be given to identifying the key indicator parameters and techniques required to detect environmental changes arising from shale gas activity in both the short-term, providing early warning, and the long-term. This will include new technology tested as part of the experiments and case studies that will allow differentiation of stimulated reservoir source fluids and other contaminants from extraneous natural and anthropogenic sources in measured groundwater, soil gas or atmospheric samples. Improved measurement, monitoring and quantification will be critical to effectively evaluating and managing the risks arising from shale gas development and supporting the integrated risk model developed as an outcome of this project.