Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p5
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 5/6)
Character Range: 2909447–2912367

new scientific data is not adequately robust, the existing HIL has been retained (with no change). Where this decision has been made, this is documented in Appendix A of this Schedule. The calculated values, before and after rounding, can be found in Appendix C.
    * HIL setting needs to be done with sufficient transparency to be replicated by other knowledgeable persons. All equations and underlying assumptions adopted in the derivation of each HIL are presented in Appendices A to C of this Schedule.
    * the HIL setting process has identified areas of uncertainty and the effect of these on the final HIL. In addition the setting of the HILs has recognised the level of uncertainty inherent in the derivation of these values and hence the HILs have been rounded to no more than 1 or 2 significant figures.
This Schedule is structured according to the five-step risk assessment process (also refer to Appendices A to D for more specific detail), which is summarised below.
    * Issues identification establishes the scope and purpose for the derivation of the HILs.
    * Data collection and evaluation entails the analysis of information about contaminants of concern and exposure pathways. Data collection for the derivation of the HILs has been carried out by literature review of Australian and international sources, and is considered according to the type of data, as part of discussion of the generic land use scenarios, the toxicity assessment and the exposure assessment.
    * Toxicity assessment identifies the effect of the contaminants of concern on sensitive populations and the most appropriate reference value for the quantitative assessment of doseresponse. The approach adopted has been to review and use relevant published peer-reviewed toxicity reference values (i.e. not to undertake a comprehensive toxicity study to derive separate toxicity reference values).
    * Exposure assessment involves the relevance and estimation of the magnitude, frequency, extent and duration of exposures to contaminants under each of the generic land use scenarios. The general exposure assessment process applied in the derivation of the HILs is described in this Schedule, as is the process applied in estimating exposure point concentrations for volatile contaminants.
    * Risk characterisation combines the outcomes of all of the previous stages of the risk assessment into quantitative and qualitative expressions of risk and uses this information to derive risk-based HIL values.
    * Uncertainty and sensitivity analysis is a key part of the risk assessment process and was undertaken during the derivation of the HILs. It identifies the key assumptions and data gaps associated with the derivation of HILs and establishes the exposure parameters that have the greatest implications for the resultant HILs. The uncertainty and sensitivity analyses provide a 'reality check' for the HILs and are