Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p29
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 29/117)
Character Range: 427226–430445

nearby surface water resources and water protection zones
    * known and/or perceived risks to the environment and/or human health including the presence of potential pathways between contaminant source(s) and potential receptors.

    8.1.3          Site-specific conditions
Site-specific conditions that may limit or govern the choice of groundwater investigation techniques include:
    * hydrogeological conditions including the depth to groundwater, soil/rock types and the presence of multiple aquifers
    * potential risks to uncontaminated aquifers and/or surface water resources
    * restrictions with regard to accessibility due to topography, ground bearing capability, site infrastructure or interference with site operations
    * risks to the environment and/or public safety
    * geotechnical limitations such as soft or saturated ground, cavernous or karstic terrains and stability
    * natural events such as flooding and shifting sand dunes.
Any of these conditions may limit the applicability of certain methods of drilling, bore installation and groundwater sampling and make other methods more practical and cost-effective.
Appropriate measures should be taken to minimise the spread of contamination by not creating migration pathways from the surface to groundwater or between different aquifers. For example, where a monitoring well is targeting a deeper aquifer unit and contamination is present in a shallow aquifer unit or overlying fill horizon, this should be cased off so as not to permit cross-contamination between the two units.

    8.1.4          Analyte-specific characteristics
The physical and chemical characteristics of contaminants have a profound effect on their sub-surface distribution and/or occurrence in groundwater at a given site. Physical and chemical characteristics that may have an effect on the distribution of contaminants include:
    * contaminant solubility
    * presence of NAPLs
    * relative density (e.g. in the case of NAPLs, LNAPLs such as oils are less dense than water, whereas dense NAPLs (DNAPLs), such as some solvents, are denser than water; for aqueous liquids, relative salinities are important)
    * stability (chemically and microbiologically)
    * partitioning characteristics (e.g. sorption and volatility)
    * aquifer redox conditions.
These characteristics will determine if contaminants are:
    * capable of leaching through a soil profile and/or are soluble in the groundwater
    * more or less dense than the groundwater, such that there is a likelihood for them to be present  close to the water table (e.g. LNAPLs or where low salinity water infiltrates into more saline groundwater) or more extensively throughout the aquifer (e.g. with DNAPLs or where saline water infiltrates through fresh groundwater)
    * relatively susceptible to effects of volatilisation, reaction with other chemicals/substances in the sub-surface, biodegradation, or attenuation.
Where there is a potential for contaminants to be present in an aquifer it is important to understand and predict where they are most likely to be concentrated prior to selecting the appropriate groundwater investigation method. Without this consideration, there is