Excavation of soil for hazardous materials

Soil

With changing community standards and the redevelopment of former industrial sites and agricultural land, there is increasing recognition of the problems associated with contaminated sites. The environmental implications of chemically contaminated land have now become a worldwide issue and in response many countries, including Australia, have developed a range of approaches to deal with the associated problems.

Historically in Australia the common practice has been for waste soil material from industrial and mining industries to be used as fill material, however there is a potential for this soil to be contaminated. Though relevant for all sites, kindergartens, primary and secondary schools have an increased requirement to ensure that contamination within the soil is not present.

Site Risk Management Program

A detailed site risk management program requires several stages such as:

Historical Review

Determine if historical use of the site and surrounding areas has the potential for contamination to be present. In conjunction with this review a site investigation is carried out to identify any obvious pollution problems.

Preliminary Soil Sampling

Based upon the site history and condition an initial sampling program can be established. Samples are taken where contamination is or may be present, as well as in areas that contamination is not suspected. The number of samples taken depends on the site history, condition and size of site. Samples are typically taken from at least two depths.

Detailed Soil Sampling Program

If the preliminary sampling program identifies the presence of contamination it may be necessary to undertake further sampling and analysis to establish the extent of the contamination.

Health Risk Assessment

The key issues for historical health risk assessments include:

  • Exposure mode and dose
  • Time of exposure
  • Toxicity of contaminated material
  • Ages and health status of children and other occupants

Risk control options are dependent upon the type, concentration and extent of contamination, but generally involve the choice of:

  • Removal of contaminated soil from the site
  • Covering of soil with a barrier material
  • Isolation of access and enforcing a no access policy
  • Interim site requirements discussed with occupants to ensure they are not exposed

A site specific risk management plan must be developed based upon the risk control or remediation options adopted. Please contact CETEC to discuss your soil management needs.