Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p19
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 19/117)
Character Range: 399131–402088

In general undisturbed samples obtained from near-continuous soil cores are preferred to grab samples for inspection and analysis. Intact soil coring is typically conducted by advancing a hollow rod or thin-walled metal tube into the sub-surface by direct push or other method such as sonic drilling. Direct push methods eliminate the need for a drilling fluid and avoid potential interferences from introduced fluids.

Auger and split-spoon samplers fitted with clear acetate sleeve liners may also be used to collect soil samples; however, sample quality is generally not as good as that obtained using direct push or sonic drilling methods.

Once soil cores have been obtained, samples from specific depth intervals can be taken and suitably preserved for laboratory analysis. Where an entire core is to be taken, the soil core tube should be quickly capped, labelled, wrapped and packed (and kept cool using ice bricks or refrigerated to keep the sample in a relatively undisturbed state) and dispatched to the laboratory for analysis.

    7.2.3          Cone Penetrometer Testing
Cone penetrometer testing (CPT) is an in situ form of direct push drilling where sensors are mounted in a cone at the tip of the drill rods. As the cone is advanced, the sensors measure the resistance of the soil to the force of the advancing cone and the data is relayed to an on-board computer which interprets the soil stratigraphy and other parameters. A range of additional sensors may be used with CPT for simultaneous measurement of multiple parameters. The range of available sensors includes pressure head transducers (allowing permeability and hydraulic conductivity assessment), conductivity probes (allowing soil types and saturation to be estimated) and nuclear and pH probes.

CPT is a useful tool for providing rapid, continuous profiles of sub-surface stratigraphy and can save considerable time and money, particularly at large sites with complex geology.

    7.2.4          Membrane interface probe
The membrane interface probe (MIP) tool consists of a heated probe equipped with a semi-permeable membrane mounted on a direct push or CPT drilling rig. VOCs diffuse across the membrane and enter a carrier gas within the probe. The carrier gas transports the contaminants to a gas chromatograph at the surface which can be equipped with various detectors for measurement of a wide range of VOCs: an electron capture detector (ECD) for chlorinated organics, a photo-ionisation detector (PID) for aromatic hydrocarbons, and a flame ionisation detector (FID) for straight-chained hydrocarbons.

For sites containing light non-aqueous phase liquids (LNAPL), MIP is typically used 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