Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 1/3)
Character Range: 2016893–2020037

2                   Site assessment process and terminology

2.1              Site assessment process
The site assessment process is shown in Schedule A. Once the need for an assessment is triggered, a preliminary site investigation (PSI) should be conducted using the guidance outlined in Schedule B2. The scope of the PSI should be sufficient to identify the potential contaminants of concern and the environmental media that are potentially affected by these contaminants.
A detailed site investigation (DSI) is required when the results of the PSI indicate that contamination is present or is likely to be present and there is insufficient information to delineate the extent of contamination and to enable site management strategies to be devised. Monitoring of groundwater conditions is an important part of the site assessment process to determine seasonal, and where appropriate, longer-term trends. The detailed investigation stage should identify the nature of the contamination and delineate its lateral and vertical extent to a sufficient degree that an appropriate level of risk assessment may be undertaken and, if necessary, to provide the basis for the development of an appropriate remediation or management strategy.
This more detailed investigation should result in an estimation of the current and projected contaminant concentrations in the receiving environment at the points of existing and realistic future use. Contaminant fate and transport modelling may be required to estimate the contaminant concentrations at these points. The investigation process should consider:
    * all potential exposure pathways
    * the properties of the contaminants such as persistence and bioavailability
    * the likely temporal variability in contaminant concentrations
    * the physicochemical and biochemical transformations that occur between the contamination source and the point of current or future realistic use.
Further guidance on related matters such as groundwater monitoring, the characterisation of groundwater contamination and the application of contaminant fate and transport modelling can be found in Schedule B2.

2.2              Groundwater investigation levels
Groundwater investigation levels (GILs) are defined as 'the concentration of a contaminant in groundwater above which further investigation (point of extraction) or a response (point of use) is required'. Selected GILs are tabulated in Table 1C of Schedule B1 and are sourced from the:
    * Australian water quality guidelines for fresh and marine water (AWQG) (ANZECC & ARMCANZ 2000)
    * Australian drinking water guidelines (ADWG) (NHMRC & NRMMC 2011)
    * Guidelines for managing risk in recreational water (GMRRW) (NHMRC 2008).
 The GILs are designed to avoid unacceptable impact to exposed populations or ecosystems under a range of circumstances. For example, the GILs for protection of freshwater and marine water ecosystems were derived using a statistical distribution method and were calculated at four different protection levels, where the data permitted, and are applied according to the ecosystem condition. The aquatic ecosystem