Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p54
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 54/117)
Character Range: 497458–500358

depths in one or more lateral locations and
    * vertical profiles of samples at two or more depths at one or more lateral locations ('transects').
Additional factors for consideration when designing and implementing an active soil vapour sampling program are discussed in Section 9.4.2.4.

9.4.2.1         Temporary spear probing
Spear probing (driven soil vapour probes) of soil involves driving a spear/rod into the ground to a shallow depth (for example, 1.5 m–2.0 m below ground surface), extracting a soil vapour sample for analysis of the vapours of concern and/or major gases (for example, oxygen), and withdrawal of the spear probe. The reliability of the results may be improved by using bentonite slurry to seal the area around the drive point and conducting a leak test prior to sampling. Samples should be recovered below the zone influenced by transient effects, which is likely to extend to 1 m or greater below the surface. The probe should be decontaminated before using at the next location.

Spear probing is generally used as a screening tool (as it permits a large number of locations to be sampled in a cost-effective manner) to inform a more detailed investigation of identified areas of interest.

The method can be used to collect samples from a vertical profile (from as shallow as 0.3 m) to assist in the identification of various vapour zones and to define the potential aerobic reaction zone. As a quantitative technique, spear probes can be installed and sampled in the same manner as permanent probes/samplers, however, it has the disadvantage that the results are 'snapshots' which cannot be later repeated.

Additional considerations associated with the sampling of soil vapour are noted in Section 9.4.4 in this Schedule.

9.4.2.2         Permanent multi-level probes/samplers
The installation of permanent multi-level probes/samplers for soil vapour measurement permits:
    * depth profiling of vapour concentrations through the soil profile from near source to near the ground surface
    * repeat sampling and monitoring over time at fixed locations.
Single depth permanent probes can either be installed at depth (close to the source) or in the shallow sub-surface (particularly where the source is shallow). Multiple depth (or multi-level) gas sampling installations may be undertaken by installing multiple sample ports at different depths (separated by a bentonite seal) within the one sampling well (API 2005; Hartman 2002), or installing separate soil vapour probes at different depths (separated by at least 0.6 m) (API 2005; NYSDOH 2006).

There is a range of methods available for installing permanent probes. The probe installation method used should be determined based on site-specific factors such as access and environmental conditions (for example, soil texture or moisture conditions that may limit the use of very narrow tubing).

A log of soil