Sorption of chlorobiphenyls in sediment-water systems containing nonionic surfactants

Nonionic surfactants may aid remediation of contaminated soils and sediments by increasing aqueous concentrations of poorly water-soluble organic contaminants. In order to explore the effects of nonionic surfactants on the sediment-water distribution of PCBs, a series of batch experiments was performed using four commercial nonionic surfactants (Triton X-100, Triton X-405, Triton X-705, and Tween 80) and Red Cedar River sediment. Sediment-water distributions of 4,4'-dichlorobiphenyl (Di-CB), 2,2',4,4'-tetrachlorobiphenyl (Tetra-CB), and 2,2',4,4',5,5'-hexachlorobiphenyl (Hexa-CB) were studied at aqueous surfactant concentrations ranging from zero to >1.5 times the critical micelle concentration (CMC) of each surfactant, The results show decreases in apparent soil-water distribution coefficients (K*) of PCB congeners at all surfactant concentrations as compared to the intrinsic sorption coefficient (K) in the absence of surfactant, unlike that previously reported. A new model incorporating a surface micellization concept for the sorbed surfactant phase was successfully applied to experimental data presented here and in a precious study.