Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:4:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 4 (pt 1/12)
Character Range: 739416–742569

4                   Sample control, preparation and storage
The laboratory should maintain rigorous procedures and documentation for sample control, from the time the sample is received. This includes the entire process from registration of the sample through to pre-treatment and sample analysis, sample storage and disposal. Unique identification of each and all portions of every sample is mandatory. Sample integrity should be maintained as far as possible, even after completion of analysis; samples should be stored in controlled refrigeration for at least two weeks after issue of analytical data, to enable repeat analysis in case any anomalous results are observed by the laboratory or the site assessor, subsequent to reporting analytical data.

4.1              Sample preparation – general principles
To obtain reproducible results it is essential that laboratories use standardised procedures when preparing samples. These procedures will not necessarily be the same for each sample but will comprise various combinations of the following treatments:
    * separation and removal of extraneous components
    * homogenising
    * drying
    * hand grinding
    * sieving
    * partitioning (to obtain representative portions).
The combination of treatments applied to any sample will depend primarily on the nature of the analytes of interest. These can be split into three broad categories:
    1. non-volatile compounds (including most metals, inorganics and some heavy organics)
    2. semi-volatile compounds (many organics, some metals and other inorganics subject to evaporative losses)
    3. volatile compounds (such as organic solvents and inorganic gases).
The following sections discuss the individual steps in sample preparation for these three categories.

Throughout the sample preparation step, the analyst should be aware of the potential for any bias to be introduced, and report any bias noted in the results.

WARNING: Handling potentially contaminated soil and fine dust may present a health hazard. All preparations described in this section should be performed in accordance with work health and safety requirements.

Asbestos or acid sulfate soils: This Section does not apply to the sampling and handling of soil containing asbestos or acid sulfate materials. For guidance consult Analysis of acid sulfate soil—dried samples—methods of test (AS 4969.0-14-2008/2009) and the Method for the qualitative identification of asbestos in bulk samples (AS 4964-2004).

4.2              Sample preparation: non-volatiles and semi-volatiles

    4.2.1         Separation and removal of extraneous (non-soil) components
Prior to processing the sample (e.g. drying, grinding or mixing), remove any vegetation and other non-soil material (including rocks, gravel, concrete, particles naturally greater than 5 mm) by hand or by sieving, except for samples to be analysed for volatile components, since this process may lead to significant analyte losses. The analyst should confirm with the site assessor or client whether any fraction of the removed material is to be analysed.

Also take a separate weighed portion of the sample