Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p20
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 20/117)
Character Range: 401811–404765

to locate and delineate dissolved-phase groundwater and soilvapour plumes, while laser induced fluorescence (LIF) (see below) is used to delineate the LNAPL source zone.
The MIP tool is usually equipped with an electrical conductivity sensor to interpret soil lithologies. The combination of sensors enables an increased understanding of contaminant distribution, particularly in heterogeneous lithologies.

One or more background MIP borings upgradient of each assessment area should be advanced in order to determine the background response. The MIP response can be used to determine concentrations of specific contaminants if it is calibrated with soil and groundwater samples from across the investigation area.

The MIP tool is typically used in the context of an adaptive sampling approach using a dynamic sampling plan and DQOs, that is, the investigation proceeds in a step-wise approach with the location and depth of each subsequent boring being determined in the field based on the results and interpretation of the preceding boreholes using a predetermined decision framework. QA/QC procedures should be developed for MIP surveys as part of the DQO process.

With multiple MIP locations and appropriate data interpolation and visualisation software, MIP data can enable a 3-D depiction of NAPL source zones in both the unsaturated (vadose) and saturated zones.

    7.2.5          Laser-induced fluorescence
The laser-induced fluorescence (LIF) tool consists of an ultraviolet (UV) or visible wavelength laser connected to a sapphire window, mounted on the side of a direct push/CPT probe tip.

The LIF laser transmits light through the sapphire window, which is then absorbed by any PAHs in contact with the window causing the material to fluoresce at a characteristic wavelength. The fluorescence emission is recorded continuously by a detection system as the probe is advanced.

LIF tools are available which, depending on the wavelengths monitored, are capable of differentiating different types of product. UV LIF systems are appropriate for light fuels up to mid-range oils, but often fail to adequately respond to heavy fuel oil, heavy crudes, coal tars and creosotes. Visible wavelength systems detect heavy fuel oil, heavy crudes, coal tars, and creosotes but do not respond to light fuels such as petrol and kerosene. If possible, an appropriate NAPL sample should be tested to ensure the appropriate wavelength LIF is used.

One or more background LIF borings upgradient of each assessment area are recommended in order to determine the background LIF response. If NAPL is present at the site, a LIF borehole should be advanced adjacent to a well where NAPL has been measured to calibrate the LIF response to the specific NAPL contamination present at the site. The LIF data should also be validated with soil and groundwater sampling to determine concentrations of specific contaminants throughout the investigation area.

As for