important variables; as additional data is collected, the uncertainty in the ‘true’ value is reduced, and it may be possible to define a smaller range for a given parameter. The uncertainty in the results of the risk assessment may therefore be reduced. Clear documentation of uncertainty is critical to communication of the reliability and confidence in the risk assessment. For further details on uncertainty management see Section 4.7.3. Risk assessment and reporting benefits those undertaking the assessment, external stakeholders and regulatory agencies. This practice provides publicly accessible evidence of a systematic approach to risk management by: demonstrating that the assessment was conducted properly providing a record of about which an organisation has knowledge reducing duplication of assessment effort improving accountability facilitating monitoring and review providing a platform for the sharing and communication of information. The above points contribute to accountability and transparency of coal seam gas operations and the management of associated risks. Publishing risk assessment reports and their associated risk sheets (Appendix E) can also help guide future research and monitoring efforts as knowledge gaps are identified. Implementing mitigating measures and managing risk Risk assessments are designed to estimate the extent of risk and inform the management of risk. Where risks are estimated to be above acceptable levels, mitigation measures must be considered. Mitigation measures are usually based on changing the potential for exposure, the intensity of the exposure, or its frequency and duration. In most situations, it is not possible to change the effects of a chemical at a particular concentration (occasionally changing the pH or other environmental conditions may change toxicity). The process of risk assessment allows an understanding of what exposure pathways are most relevant in order to better target mitigation measures (and to avoid any unnecessary mitigation). Where there are no acceptable mitigation measures to achieve an acceptable level of chemical risk, the need to use the relevant chemical, or suite of chemicals, must be reassessed. The framework for implementing risk management should include (from AS/NZS, 2009): defining the appropriate timing and strategy for implementation applying the framework for environmental and / or human health risk assessment to the chemicals being assessed complying with legal and regulatory requirements ensuring decision-making, including the development and setting of objectives, is aligned with outcomes from the risk assessment holding information and training sessions
Tetrakis (hydroxymethyl) phosphonium sulfate (THPS) mg/L Formaldehyde mg/L Total residual chlorine ppm Table 13: Environmental Isotopes Parameter Analysis Tritium (3H) Tritium analyses Provides information about younger groundwater ages and mixing; can be used to confirm the presence or absence of younger groundwater Chlorine-36 and Chlorine-37 (36Cl and 37Cl) Chlorine analyses Provides information about older groundwater ages and mixing Helium-4 (4He) Helium-4 analyses Provides information about vertical groundwater flow through aquifers and aquitards (Kv) over time, formation-scale porosity, groundwater flow rates, and paleoclimatic conditions Oxygen-18 (18O) Oxygen-18 and Deuterium analyses Provides information about the origin of natural waters and processes that have affected groundwater since it entered the groundwater system Deuterium (2H) Strontium-87 (87Sr) Strontium-87 and Strontium-86 analyses Provides information on interactions and the provenance of aquifer rock formations; Strontium-86 (86Sr) Carbon-13 (13CDIC) Carbon-13 and methane isotope analyses Provides information groundwater age Radiocarbon (14C) Radiocarbon aging analysis Provides information about groundwater age Methane (13C-CH4) Carbon-13 and methane isotope analyses Provides information about thermogenic or biogenic origins of dissolved methane in groundwater Methane (2H-CH4) (11B) Sulfur-32 and Sulfur-34 (32S, 34S) Lithium-7 (7Li) (222Rn), CFCs CFC-12), Sulfur hexachloride (SF-6) gasses: 4He, 20Ne, 36Ar 85KR Other geochemical, isotopic, CFC tracer, and noble gas analytes Distinguishes the presence, source, and tracks the crustal movement of gas and fluids through time; identifies and quantifies surface water- groundwater interaction and hyporheic exchange rates; ages younger groundwater
Appendix B: Checklists Table C.1 Planning and problem formulation (for both human health and environmental risk assessment) Planning and problem formulation  1 Define the management goals of the risk assessment and applicability of regulatory requirements 2 Define the and objectives of the risk assessment to clearly identify the problem 3 Generate conceptual models representing predicted key relationships between stressors, exposure and assessment endpoints 4 Identify the methodology and complexity (tier level) for analysing the risk (exposure and hazard), keeping in mind this may evolve as the assessment progresses 5 Consider multiple hazards and cumulative impacts 6 Are the data available and accessible? What are the data quality criteria? What are the data gaps and uncertainties? 7 Have the interests and concerns of affected parties been considered in formulating the problem? Table C.2 Data requirements (for both human health and environmental risk assessment) Data requirements  1 Identify the chemical, mixtures or chemical identities in mixtures / flowback / produced water / wastewater (Section 4.1) 2 Obtain chemical information, along with information of fate and behaviour of the chemical(s) in the environment (Section 4.2) 3 Gather data for the exposure assessment (i.e. chemical quantities and concentrations, exposure routes and compartments) (Section 4.3) 4 Gather data for the hazard assessment (Section 4.4) 5 Evaluate data quality (Section 4.6) and determine if further data are required 6 Determine, analyse and report on the uncertainty within the acquired data (Section 4.7.3) 7 Analyse weight of evidence to determine the adequacy of the available data as a whole (Section 4.7.4) Table C.3 Human Health Exposure Assessment Human health exposure assessment  1 Identify the chemical sources and define points of release of chemical(s). 2 Identify and define transfer pathways for the chemical(s) 3 Identify and define the receptors and exposure routes (occupational exposure and public exposure) applicable to the situation being assessed. 4 Describe, measure and / or calculate exposure concentrations for occupational exposure and public exposure. 5 Describe approach, models used and uncertainties around the data used.
Where: MoE = Margin of Exposure PoD = of Departure (e.g. NOAEL) in mg/kg/d Intake = Intake in mg/kg/day from all exposure routes the margin of exposure during human health risk characterisation. 6 Where: RQ = Risk Quotient Intake = Intake in mg/kg/day T-TRV = Threshold Toxicity Reference Value (TRV) in mg/kg/day Formula used to derive the risk quotient during human health risk characterisation. 7 Overall RI = ∑RQ for each exposure pathway RQ = Risk Quotient Formula used to derive the risk index during human health risk characterisation. 8 Where: ILCR = Increased lifetime cancer risks Intake = Intake in mg/kg/day Exposure concentration = Exposure concentration in mg/m3 TRV Reference Value mg/kg/day Formula used to derive the increased lifetime cancer risk during human health risk characterisation. 9 PNEC = Predicted No Effect Concentration Assessment factor = safety or uncertainty factor General formula for calculating a Predicted No Effect Concentration. - MATC = Maximum Acceptable Toxicant Concentration NOEC = No Observable Effects Concentration LOEC = Lowest Observable Effects Concentration General formula for calculating the Maximum Acceptable Toxicant Concentration (MATC) Included here, for information only. Its use is not recommended (previously used in effects assessment – reported as the geometric mean between NOEC and LOEC)
Reporting: [insert text] Risk communication and management Recommendations for risk mitigation: Classification and labelling Classification: [insert GHS classifications] Labelling: [insert GHS labelling text] Pictograms: [insert GHS pictograms] Classification: [insert Proposed CoAG National Standard for Environmental Risk Management of Industrial Chemicals Schedules] Recommendations for risk mitigation: Safety and handling First Aid: [insert text] Fire Fighting: [insert text] Accidental Release: [insert text] Storage and Handling: [insert text] Exposure Controls – Engineering: [insert text] Exposure Controls – Personal Protection: [insert text] Exposure Controls – Administrative: [insert text] Transportation: [insert text] Recommendations for risk mitigation: Disposal Disposal – chemical residues: [ insert text] Disposal – packaging and containers: [ insert text] Disposal – plant and equipment: [ insert text] Recommendations for risk mitigation: Monitoring and reporting Monitoring: [insert text] Reporting: [insert text]