Land sites historically overlain by e.g. tailings storage facilities and mine dumps are potentially contaminated by radioactive residues. Regulations require the issue of a radiological site clearance certificate before such a site may be used for public habitation. This entails surveying of the radioactivity content of the soil, and comparison to regulatory levels. However, radon gas intruding from underlying soil into buildings is the major component of radiation exposure to future inhabitants on a previously contaminated site. Radioactivity surveys do not provide information on radon intrusion and the intrusion rate and radon levels have to be determined to assess the safety of future habitation. This data should form part of the site clearance certificate, hence the colloquial expression of “radon certificate”.
PARC Scientific offers analysis of radon intrusion using internationally accepted, and validated in-house developed models. The method has been used extensively to assess radiological dose on contaminated sites. Removal of contaminated soil is often required to reduce site average radioactive content levels. This can be an expensive exercise. PARC Scientific offers iterative modelling methodologies to optimise this process by limiting soil removal to selected locations.