surface water bodies 5b Seepage Seepage relationships between groundwater and surface water bodies are poorly quantified. Integrated relationships modelling and measurements of seepage in priority areas will improve understanding of potential between surface impacts of coal seam gas extraction and coal mining. and groundwater 5c Linking surface Surface water and groundwater models are usually at different spatial and temporal scales. This research water and priority would investigate ways to improve modelling of surface water impacts at finer scales. Linked to groundwater Hydrology priority 1b. models CHEMICALS 1 The fate, There is limited information about liquid and gas migration from production wells or target coal seams to aquifers (particularly at depth), and long-term liquid and gas migration from the fracture zone via transformation and degradation pathways in subsurface rock formations. Developing and applying stable isotope methods to detect of hydraulic contamination in aquifers is one possible research strategy. fracturing fluids 2 The effects of Hydraulic fracturing fluids have the potential to mobilise geogenic contaminants. Potential mobilisation is fracturing fluids affected by elevated temperature, pressure, coal type and fracturing composition. Improved on the release understanding is needed of the transformation and fate of geogenics, including volatile geogenics and new behaviour of products formed during fracturing, under different physico-chemical conditions. geogenic contaminants 3 Composition and Knowledge on the composition and effects of flowback and produced water is required. In particular: effects of flowback development of analytical laboratory methods for detecting and quantifying their composition; and produced characterisation of their physico-chemical, chemical and ecotoxicological properties; identification of factors that influence their composition (e.g. formation type, fracturing fluids used, sub-surface processes, interaction with mobilised geogenics and residence time); and determination of their bioaccumulation and effects on aquatic ecosystems. The toxicity of mixtures and the interactive effects of chemical additives also need investigation. 4 Waste water A review of treatment options (e.g. reverse osmosis) for waste water from coal seam gas and coal mining management operations, considering: their effectiveness especially for total dissolved solids and endocrine-disrupting chemicals; effects of conductivity and total dissolved solids on freshwater aquatic biota (e.g. stygofauna, turtles, frogs); the persistence and mobilisation in soil/sediments of naturally occurring radioactive
surface water bodies 5b Seepage relationships between surface and groundwater Seepage relationships between groundwater and surface water bodies are poorly quantified. Integrated modelling and measurements of seepage in priority areas will improve understanding of potential impacts of coal seam gas extraction and coal mining. 5c Linking surface water and groundwater models Surface water and groundwater models are usually at different spatial and temporal scales. This research priority would investigate ways to improve modelling of surface water impacts at finer scales. Linked to Hydrology priority 1b. CHEMICALS 1 The fate, transformation and degradation of hydraulic fracturing fluids There is limited information about liquid and gas migration from production wells or target coal seams to aquifers (particularly at depth), and long-term liquid and gas migration from the fracture zone via pathways in subsurface rock formations. Developing and applying stable isotope methods to detect contamination in aquifers is one possible research strategy. 2 The effects of fracturing fluids on the release behaviour of geogenic contaminants Hydraulic fracturing fluids have the potential to mobilise geogenic contaminants. Potential mobilisation is affected by elevated temperature, pressure, coal type and fracturing composition. Improved understanding is needed of the transformation and fate of geogenics, including volatile geogenics and new products formed during fracturing, under different physico-chemical conditions. 3 Composition and effects of flowback and produced Knowledge on the composition and effects of flowback and produced water is required. In particular: development of analytical laboratory methods for detecting and quantifying their composition; characterisation of their physico-chemical, chemical and ecotoxicological properties; identification of factors that influence their composition (e.g. formation type, fracturing fluids used, sub-surface processes, interaction with mobilised geogenics and residence time); and determination of their bioaccumulation and effects on aquatic ecosystems. The toxicity of mixtures and the interactive effects of chemical additives also need investigation. 4 Waste water management A review of treatment options (e.g. reverse osmosis) for waste water from coal seam gas and coal mining operations, considering: their effectiveness especially for total dissolved solids and endocrine-disrupting chemicals; effects of conductivity and total dissolved solids on freshwater aquatic biota (e.g. stygofauna, turtles, frogs); the persistence and mobilisation in soil/sediments of naturally occurring radioactive