Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:4:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 4 (pt 2/12)
Character Range: 742323–745312

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 to determine moisture content (see Analytical Methods, Section 5 in this Schedule). Report moisture content with the analytical result so that analyte concentrations may be estimated on a 'dry-weight' basis.

As stated previously, the analytes of concern should be the 'available' contaminants, which generally reside on the surface of the soil particles. It is likely that larger particles and rocks will contain, on a weight basis, considerably less contaminant than the smaller particles. In certain circumstances, however, it will be prudent to also analyse the larger particles, preferably separately. The reverse will be likely if contamination of a site has arisen by importation of contaminated screenings or other large particles.

Any material removed for analysis should be weighed and its proportion relative to the entire sample, and its description, recorded. If required, this mass and the description may be included in the analytical report. The significance of the analyte concentration in the soil or fraction of removed material can then be assessed relative to the entire sample composition.

The removed material (including the materials retained on the sieve) should be labelled and retained for possible future analysis.

    4.2.2         Homogenising (for non-volatile constituents)

Note: This section only applies to non-volatile samples; samples of volatile contaminants should not be homogenised by stirring, grinding or sieving. Procedures for volatile analytes are described in Section 4.3 below.

Most analytical methods require analysis of only a portion of the sample, sufficient to provide a quantifiable response. The amount of sample received by the laboratory is usually larger than required for a single determination and any additional analyses for QA purposes.

Depending on the analyses required (excluding volatile analysis), a homogeneous test sample is prepared from either the field-moist (i.e. 'as received') or dried sample. The analysis portions are then taken from this test sample.

The sub-sample taken should comprise at least 25% by weight or 200 g of the sample received by the laboratory (laboratory sample), whichever is the smaller, or some other sub-sample that can provide a well-mixed portion representative of the whole sample. It should be thoroughly disaggregated and mixed using a mortar and pestle, or other appropriate method. If no test requiring the original untreated sample will be needed in future, the entire sample may be homogenised; however, it is advisable to keep a portion in the 'as received' state to check, if necessary, that no contamination has occurred during the homogenising process. Described below are the pre-treatment procedures to obtain homogenised