The phase distribution of polychlorobiphenyl congeners in surfactant-amended sediment slurries

The surfactant-aided recoveries of polychlorobiphenyls (PCBs) from a sample of Ashtabula River (Ohio) sediment were compared to calculated recoveries based on an equilibrium phase distribution model. The equilibrium model contains as parameters: (i) the surfactant concentration in the micelles, [S]mic, (ii) the mass of organic carbon in the sediment (or soil) per aqueous volume, oc, (iii) a constant characterizing solute affinity for the micelle (β = Km/Kow), and (iv) a constant characterizing solute affinity for the sediment carbon (α = Koc/Kow). The recovery of specific PCB congeners from the sediment by surfactant micelles at equilibrium were invariant with congener number as predicted by the model. This invariant behavior results from the fact that the PCBs are partitioned between two lipophilic phases (soil organic carbon and micelles) through hydrophobic interactions. Surfactants chosen as solubilizing agent were Brij 30, polyoxyethylene-10-lauryl ether, Brij 35, Triton X-705, Tween 20, Tween 80, Tween 85, Exxal F5715, Pluronic P-65, and sodium dodecylsulfate.