Desorption kinetics of chlorobenzenes, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls: Sediment extraction with Tenax(R) and effects of contact time and solute hydrophobicity

A technique using Tenax TA (R) beads as ''sink'' for desorbed solute was employed to measure the kinetics of desorption of chlorobenzenes, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons from laboratory-contaminated sediment. First-order rate constants of rapid and slow desorption were in the order of 10(-1)/h and 10(-3)/h, respectively. The rate constants of slow desorption correlate well with the molecular volumes of the compounds used and decrease between 2 and 34 d of equilibration. Slowly desorbing fractions increase with both increasing solute hydrophobicity and increasing equilibration time.