Bioavailability of benzo[a]pyrene in soils using a swine model

Sorption of hydrophobic organic contaminants (HOCs) to soil is suggested to be dominated by the soil organic matter. However limited data is available for that to be used to adjust risk assessment for human exposure, and the potential risk is mainly estimated by the total extractable concentration using an exhaustive solvent extraction method. This study is especially designed to study the possible influence of soil properties on HOC bioavailability. Benzo[a]pyrene, with K_ow of 6 is used as a model compound to represent HOCs. In total 19 soils collected from across Australia with varied soil properties were spiked at a same concentration of ~10 times of its soil guideline value and dosed to swine with food after aged for 90 days. The contaminant bioavailability was measured by the area under the plasma Banzo[a]pyrene concentration over 24 h. As a swine model is accepted as appropriate to represent human for exposure, bioavailability from this study would give a strong evidence of the associated risk to human. (author)