Abstract

A methodology based on a tiered (three-step) approach was developed to enable site-specific assessment of risks of soil contamination with asbestos. Along with the presentation of this methodology, we have endeavoured to underpin the Intervention Value for soil remediation for asbestos, which was recently released by the Dutch Ministry of Housing, Spatial Planning and the Environment in its interim policy on asbestos in soil. Because risks to humans after inhalation of asbestos are the most critical, the risk assessment was based on the probability of asbestos fibre emission from soil to air, making a distinction between chrysotile and amphibole asbestos, bound and friable asbestos, and the respirable and non-respirable fraction in soil. Because the behaviour of asbestos in soil is different from the behaviour of any other soil contaminant, the CSOIL exposure model was not used. Instead, use was made of measuring results, i.e. the concentrations of asbestos in soil and air, for deriving the Intervention Value. Guidance on measurement procedures has been incorporated into tiers 2 and 3 of the methodology for determining site-specific human risks.