FACILITATED TRANSPORT AND ENHANCED DESORPTION OF POLYCYCLIC AROMATIC-HYDROCARBONS BY NATURAL ORGANIC-MATTER IN AQUIFER SEDIMENTS

Natural organic matter (NOM) at environmentally feasible concentrations significantly facilitates transport and enhances desorption of polycyclic aromatic hydrocarbons (PAH) in low organic carbon (f(oc)) aguifer sediments. Soil-derived humic materials do so with greater effect than do aquatic-derived humic materials. As well, the effects are greater for more hydrophobic PAH than for PAH of lower hydrophobicity. PAH-NOM association is dynamic and reversible. Movement of PAH to and from NOM and to and from low f(oc) sediment occurs rapidly, making possible the use of NOM in enhancing PAH desorption. Corollary to this observation is the ability of PAH to move from NOM to sediment, which must be considered in any prospective remediation scheme. Facilitation and enhanced desorption of PAH by NOM was successful because of the absence of kinetic limitations in the system herein examined.