Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p68
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 68/117)
Character Range: 537179–540193

Many Australian soils are weakly acidic, however, some sites may contain acid sulfate soils or other acidic soil conditions that can lead to faster rates of degradation. The clay and moisture content of soils is also a consideration, as these factors tend to inhibit the release of fibres by binding and damping mechanisms.

11.3          Detailed site assessment
A DSI may not be necessary although this will depend on the site-specific circumstances and the proposed remediation approach. Conservative management of presumed asbestos contamination may avoid the need for a DSI. The circumstances where a DSI would be necessary include when:
    * the remediation or management approach requires asbestos contamination to be fully delineated and assessed (e.g. asbestos contamination is to be relocated and contained on-site)
    * land uses are to be determined and delineated according to the extent and nature of the asbestos contamination.
A DSI may also resolve uncertain findings from the PSI, or assist in assessing the likely effectiveness of alternative remediation and management strategies.

A DSI is not necessary where there is a high degree of confidence that the asbestos contamination is confined to bonded ACM in superficial soil, i.e. the site history can be established with confidence and this clearly indicates that there is no reason to suspect buried asbestos materials and the site inspection confirms that any bonded ACM is in sound condition and only present on the surface/near surface of the site. In these circumstances the assessment can proceed directly to remediation (removal of bonded ACM fragments and ensuring that the soil surface is free of visible asbestos) and validation. However, investigation will be required if the soils at the site have been disturbed and potential asbestos-contaminated-material moved around the site or incorporated into sub-surface soils.

Unnecessary investigations should be avoided, for example, investigation for bonded ACM is not recommended below the proposed deepest excavation level during construction or likely maximum depth of disturbance for the proposed/current land use.

    11.3.1      Sampling and analysis
If a DSI is undertaken, a sampling and analysis quality plan (SAQP) is required to support and inform the investigations. A site management plan, including dust management and airborne fibre monitoring, may also be required to protect the public and workers during investigation works and earthmoving/development works. Asbestos fibre and dust (as a surrogate for asbestos fibre) are of particular interest. Dust management measures should be adopted to ensure that airborne fibres remain below 0.01f/ml, which is the practical lower detection limit of the membrane filter method (enHealth 2005). Any dust-related asbestos fibre analysis should be undertaken by a NATA-accredited laboratory. For further information and guidance on dust and airborne fibre monitoring refer to WA DoH (2009a) and enHealth (2005) and relevant