Abstract
Humic substances (HSs) are naturally occurring surface-active materials that have an amphiphilic nature for both hydrophilic and hydrophobic properties. Such functions of HSs do not serve as only sorption of hydrophobic organic pollutants (HOPs), such as polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and pesticides to soil particles, but also as solubilization that leads to the movement and diffusion of HOPs. These antithetic properties of HSs have been attempted to apply to remediation techniques for contaminated soils and groundwater. Such unique characters of HSs for HOPs can be attributed to the fact that HSs are known to be heterogeneous materials in which the structural features are varied by the conditions of their genesis. However, the heterogeneity of HSs can yield difficulties in estimating how HSs are effective when these are applied to contaminated sites. In this paper, we review previous studies concerning the functions of HSs with respect to the interaction with HOPs ; also prospects for applying the HS functions to soil remediation are discussed.
