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

Natural organic matter (NOM) at environmentally feasible concentration s significantly facilitates transport and enhances desorption of polyc yclic aromatic hydrocarbons (PAH) in low organic carbon (f(oc)) aguife r sediments. Soil-derived humic materials do so with greater effect th an do aquatic-derived humic materials. As well, the effects are greate r for more hydrophobic PAH than for PAH of lower hydrophobicity. PAH-N OM 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 observa tion is the ability of PAH to move from NOM to sediment, which must be considered in any prospective remediation scheme. Facilitation and en hanced desorption of PAH by NOM was successful because of the absence of kinetic limitations in the system herein examined.