Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:6:p4
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 6 (pt 4/4)
Character Range: 3027643–3028849

fruit would actually be cultivated in soils with an organic carbon content as low as 0.3% and a value of Foc= 2% was selected to apply to the vegetable pathway. In areas where lower levels of organic carbon are present in soil in the root zone, this needs to be considered in a more site-specific assessment for organic contaminants of concern. The Foc does not affect the assessment of plant uptake of inorganic compounds; however it is important for organic compounds.

    6.5.2         Vapour intrusion rate
The assessment of vapour intrusion for volatile organic chlorinated compounds (VOCC) has not been conducted using a model; rather, it is based on measured soil vapour and indoor air concentrations and associated attenuation factors. The measured attenuation factors range over several orders of magnitude reflecting the wide range of sites and conditions included in the database. Indoor and outdoor air exposure concentrations are linearly related to the attenuation factor used. Hence, the adoption of an attenuation factor that is ten times lower will result in an indoor or outdoor air exposure concentration that is ten times lower, and an interim soil vapour HIL that is ten times higher.